JP2018083759A - Cosmetic - Google Patents

Abstract

The present invention provides a cosmetic material that has high shielding properties and makes wrinkles inconspicuous due to diffused reflection of light. A cosmetic comprising hollow silica particles having an average particle diameter of 0.1 μm to 30 μm and an outer shell thickness of 5 nm to 500 nm. The carbon content of the empty silica particles is preferably 3% by mass or more. Further, when a coating film having a thickness of 30 μm was prepared using a composition containing 20% by mass of hollow silica particles in trimethylsiloxysilicic acid, the haze of the coating film was compared with the coating film not containing hollow silica particles. The value is preferably 50% or more, and the total light transmittance is preferably 90% or less. [Selection figure] None

Description

  The present invention relates to a cosmetic, and more particularly to a cosmetic containing hollow silica particles.

As an additive to be added to cosmetics, silica is one of the commonly used substances, and various types of silica having different properties such as shape and pore properties are blended according to the purpose of use.
Various examples such as amorphous silica, spherical silica, solid silica, porous silica, and hollow silica are known as silica powders to be blended in cosmetics.

  The hollow silica particles have an outer layer made of silica, an inner core hollow and an air layer. By applying the hollow silica particles to the skin as a cosmetic, wrinkles and pores on the skin can be made inconspicuous due to the diffuse reflection effect of light. In addition, since the apparent density of the particles is small, it is possible to give the skin a light touch when applied.

Patent Document 1 proposes the provision of a nano hollow particle composed of a silica shell that is less agglomerated into secondary particles and highly dispersible, and a method for producing the nano hollow particle.
Patent Document 1 discloses nano hollow particles having an outer diameter of 30 to 300 nm, a silica shell thickness of 1 to 5 nm, and at most 5 to 30 nm (paragraph 0063).

Patent Document 2 proposes a coating composition containing hollow SiO ₂ having an average aggregate particle diameter of 60 to 400 nm and an average primary particle diameter of 5 to 50 nm. Patent Document 3 proposes manufacturing hollow SiO ₂ by removing the core from core-shell type fine particles whose outer shell is SiO ₂ .

  In Patent Document 3, in cosmetic formulations, hollow particles having a specific narrow particle size distribution and an average particle size of 200 to 700 nm exhibit low permeability and a more natural appearance in addition to high coverage. Some hollow particles are proposed.

No. 2012-121130 Japanese Patent No. 4883383 Special table 2009-504632 gazette

  The surface of human skin has a color, and its structure is not a simple plane, but has a unique structure and properties with grooves having an average depth of about 10 μm. The roughness of the skin is an obstacle to producing a beautiful makeup effect. In particular, with age, the grooves on the surface deepen, creating shadows on the light and making wrinkles and pores more noticeable. Therefore, development of cosmetics that can improve the surface of such human skin is required.

Patent Documents 1 and 2 disclose a method for producing hollow silica particles, but as cosmetics, how the physical properties such as the shape of the hollow silica particles affect the shielding properties and the light irregular reflection effect. Not considered.
Moreover, in patent documents 1-3, since the particle diameter of a silica is small, there exists a problem that the handling as a powder is difficult and it is hard to mix | blend with cosmetics.
For hollow silica particles having a large particle size, the thickness of the outer shell silica, the resistance to water and sebum, and the affinity for cosmetic solvents are important in order to obtain the effect of diffuse reflection of light.
An object of the present invention is to provide a cosmetic that has high shielding properties and makes wrinkles inconspicuous due to diffused reflection of light.

  One aspect of the present invention is a cosmetic including hollow silica particles having an average particle diameter of 0.1 μm to 30 μm and an outer shell thickness of 5 nm to 500 nm.

  ADVANTAGE OF THE INVENTION According to this invention, the cosmetics which have high shielding property and make wrinkles inconspicuous by the light irregular reflection effect can be provided.

Hereinafter, although one embodiment concerning the present invention is described, the present invention is not limited by the illustration in the following explanation.
The cosmetic according to an embodiment of the present invention is characterized in that it contains hollow silica particles having an average particle diameter of 0.1 μm or more and 30 μm or less and an outer shell thickness of 5 nm or more and 500 nm or less.
According to the present embodiment, it is possible to provide a cosmetic that has high shielding properties and makes wrinkles inconspicuous due to diffused reflection of light.

According to this embodiment, when the average particle diameter of the hollow silica particles is in the above range, the hollow silica particles are applied so as to cover the wrinkle portion of the skin, and the uneven shape such as wrinkles can be made inconspicuous. .
According to this embodiment, when the thickness of the outer shell of the hollow silica particles is in the above range, light is irregularly reflected between the air layer of the hollow portion of the hollow silica and the silica layer of the outer shell, and wrinkles. Can be made less noticeable.
If the silica particles are solid or liquid enters the hollow silica particles, the silica particles are less likely to reflect light.
In addition, when using hollow silica particles having a large particle size, the thickness of the outer shell of the hollow silica particles is in the above range, so that the strength of the hollow silica particles is increased and the air layer of the inner core is appropriately maintained and light. A touch can be imparted.

<Hollow silica particles>
The shape of the hollow silica particles is not particularly limited as long as they are hollow particles, and may be spherical, cubic, rugby ball, rod, spindle, column, tube, sheet, or a combination thereof. it can. It is preferable that the hollow silica particles have a spherical shape including a true sphere and an ellipsoid as a whole from the viewpoint of touch as a cosmetic. Moreover, a light touch can be provided by being a hollow particle.

The hollow silica particles have an average particle size of 0.1 μm or more and 30 μm or less.
When the average particle diameter of the hollow silica particles is in the above range, the hollow silica particles can be applied so as to cover the wrinkles of the skin when the cosmetic is applied to the skin. Moreover, it becomes easy to handle the hollow silica particles as a powder.
When the average particle diameter of the hollow silica particles is less than 0.1 μm, it is very difficult to handle as a powder. In addition, the hollow silica particles may penetrate deep into the wrinkles of the skin, and the effect of irregular reflection of light from the hollow silica particles may not be sufficiently obtained. Moreover, it can prevent that a particle | grain fits into uneven | corrugated | grooved parts, such as a wrinkle of skin, and peels off after application because the average particle diameter of a hollow silica particle is 30 micrometers or less.

The average particle diameter of the hollow silica particles is more preferably 1 μm or more, and further preferably 3 μm or more.
The average particle diameter of the hollow silica particles is more preferably 20 μm or less, and further preferably 15 μm or less.
Here, the average particle diameter of the hollow silica particles is an average particle diameter in terms of volume in a measurement method by a laser light scattering method.

The hollow silica particles have an outer shell thickness of 5 nm to 500 nm.
When the thickness of the outer shell of the hollow silica particles is within the above range, the hollow portion of the hollow silica particles holds an air layer on the skin surface, and the silica layer of the outer shell is irregularly reflected by external light. The uneven shape such as wrinkles can be made inconspicuous.
In addition, the hollow silica particles have a shell thickness of 5 nm or more, so that sufficient hollow silica particle strength can be obtained, and the hollow silica particles can be used during the use of cosmetics and in the production process of cosmetics. It can prevent that a particle | grain breaks and can prevent that the touch of cosmetics falls.
On the other hand, when the thickness of the outer shell of the hollow silica particles is 500 nm or less, the size of the hollow portion can be made appropriate, and the effect of irregular reflection by the air layer can be sufficiently obtained.
Moreover, when the thickness of the outer shell of the hollow silica particles is 500 nm or less, the apparent density of the particles can be reduced, and a good feel when applying cosmetics can be imparted.

The thickness of the outer shell of the hollow silica particles is more preferably 10 nm or more, more preferably 50 nm or more, and further preferably 70 nm or more.
The thickness of the outer shell of the hollow silica particles is more preferably 400 nm or less, and even more preferably 300 nm or less.
As a method for measuring the thickness of the outer shell of the hollow silica particles, there is a method in which a cross section of a sample particle is obtained and measured using a scanning electron microscope. As a method for obtaining the cross section of the sample particle, for example, a method using a cross section polisher, a method of crushing the particle, or the like can be used. The thickness of the outer shell of the hollow silica particles is an average value obtained by arbitrarily measuring five particles having a size corresponding to 50 to 150% of the average particle diameter measured by a laser light scattering method.

The thickness of the outer shell of the hollow silica particles is preferably 0.5 to 20%, more preferably 1 to 15%, still more preferably 2 to 10% with respect to the above average particle diameter. is there.
Within this range, sufficient strength can be obtained with the optical properties, storage stability, and good feel of the hollow silica particles.

The hollow silica particles preferably have a carbon content of 3% by mass or more based on the total amount of the hollow silica particles.
By including an organic component in the hollow silica particles, the hollow silica particles easily repel moisture. And it can prevent that a water | moisture content permeates into a hollow part from the fine hole of the outer shell of a hollow silica particle. As a result, it is possible to prevent the light scattering performance from deteriorating due to moisture entering the hollow portions of the hollow silica particles on the surface of the skin.
Similarly, by containing organic components in the hollow silica particles, liquid components contained in cosmetics, sebum and the like are prevented from entering the hollow portions of the hollow silica particles, and higher light scattering performance is obtained. be able to.
The amount of the organic component of the hollow silica particles can be measured as the carbon content. The carbon content is more preferably 5% by mass or more, and more preferably 8% by mass or more, with respect to the total amount of the hollow silica particles.

On the other hand, when the amount of the carbon component in the hollow silica particles is excessive, the strength of the outer shell of the hollow silica particles is lowered, and the hollow silica particles may be cracked when the cosmetic is used. In addition, in the cosmetic preparation process, when the hollow silica particles are mixed, the hollow silica particles may break.
The carbon content of the hollow silica particles is preferably 25% by mass or less, more preferably 20% by mass or less, and further preferably 15% by mass or less with respect to the total amount of the hollow silica particles.

  As a method for measuring the carbon content of the hollow silica particles, there is a method in which a small amount of sample is burned in a furnace heated to 1000 ° C., and the amount of carbon dioxide produced is subjected to mass spectrometry to measure the amount of carbon. A Perkin Elmer “2400II, CHN meter” can be used as the mass spectrometer.

The hollow silica particles were applied to a coating film containing no hollow silica particles when a coating film having a thickness of 30 μm was prepared using a composition containing 20 mass% hollow silica particles in trimethylsiloxysilicic acid. The haze value of the film is preferably 50% or more, and the total light transmittance is preferably 90% or less.
Specifically, using a composition containing 20% by mass of hollow silica particles in trimethylsiloxysilicic acid, the composition was applied to a transparent substrate so that the coating thickness was 30 μm, and dried. A film having a thickness of 30 μm is formed. A PET film etc. can be used as a transparent base material.
A reference coating film is formed in the same manner using a composition containing only trimethylsiloxysilicic acid and not containing hollow silica particles.
About this coating film, a haze value and a total light transmittance can be measured by the method based on JISK7105. The haze value and total light transmittance of the coating film are expressed as relative values with respect to 100% of the reference coating film.

This haze value is 50% or more and the total light transmittance is 90% or less, so that sebum and oil in cosmetics are prevented from entering the hollow part of the hollow silica particles, After applying the cosmetic to the skin, it is possible to maintain a high light diffuse reflection effect for a long time.
In the hollow silica particles according to the present embodiment, the haze value and the total light transmittance can be adjusted to the above ranges by appropriately adjusting the average particle diameter, the thickness of the outer shell, the carbon content, the particle shape, and the like.

This haze value is preferably 50% or more, and more preferably 60% or more, from the viewpoint of light diffusibility. A haze value close to 100%, which is the upper limit in principle, is preferable for the purpose of blurring wrinkles and stains because of its high ability to block linearly transmitted light.
This total light transmittance is preferably 90% or less, and more preferably 85% or less, from the viewpoint of shielding properties.
The lower limit of the total light transmittance is preferably 30% or more, and more preferably 40% or more, from the viewpoint of the appearance when applying cosmetics.

The strength of the hollow silica particles is preferably 3 MPa or more.
If the strength of the hollow silica particles is not sufficient, the hollow silica particles may break during use of the cosmetic or in the production process of the cosmetic, and optical characteristics may not be obtained. Moreover, since the broken particles are not in the form of particles, the touch may be deteriorated.
The strength of the hollow silica particles is more preferably 5 MPa or more, and further preferably 10 MPa or more. The strength of the hollow silica particles is preferably as high as possible, and the upper limit value is not limited.
Regarding the mechanical strength of fine particulate silica gel or the like, for example, the following formula of Hiramatsu et al. Is known as a general formula of mechanical strength in the case of spherical particles (Hiramatsu et al .: Journal of the Japan Mining Association, 81, 10, 24 (1965)).
Sp = 2.8 × Sc / (π × d × d)
In the above formula, Sp (MPa): powder strength, Sc (N): compressive strength, d (mm): particle diameter.
The mechanical strength of the hollow silica particles according to the present embodiment can be measured by a micro compression tester “MCTM-500 type” manufactured by Shimadzu Corporation according to the above formula. Specifically, when a particle having a particle diameter d is loaded at a constant speed, it is shown that the sample particle is crushed at a point where the change in load rapidly increases, and the load at this point is defined as compressive strength Sc. The particle strength Sp can be determined. In this way, the particle diameters d1, d2,..., Dn are measured, and the average value is obtained. In the present embodiment, the particle strength is obtained from the average value of 30 particles. In the measurement of particle strength, the value measured with an optical microscope is used as the particle diameter d.

The hollow silica particles are preferably precipitated in ethanol at 25 ° C.
Thus, it can confirm that the silica of the outer shell of a hollow silica particle permeate | transmits ethanol because a hollow silica particle settles in ethanol.
When the hollow silica particles do not settle in ethanol, it can be said that the hollow portion of the hollow silica particles remains in the air layer even in ethanol, and the outer shell silica of the hollow silica particles is dense. In such a state, in the dispersion-type cosmetic, the specific gravity of the hollow silica particles is small and it is difficult to disperse or settle in the solvent, and it is difficult to uniformly disperse the hollow silica particles in each component.
Since ethanol permeates through the hollow silica particles, the apparent density of the particles can be made close to the density of the solvent, so that the hollow silica particles are easily dispersed in a low molecular weight organic solvent such as ethanol.
In addition, since low molecular weight organic solvents such as ethanol evaporate into the air after cosmetics are applied to the skin, the hollow silica particles can have excellent optical properties because the hollow portion is hollow on the skin surface. it can.

  Here, the hollow silica particles are precipitated in ethanol under the above-mentioned conditions. At 25 ° C., the hollow silica particles are added from the top of ethanol having a depth of 3 cm from the liquid surface to the bottom surface under atmospheric pressure without stirring. When left standing for 1 hour, it is in a state where it can be visually confirmed that hollow silica particles of 70% by mass or more of the charged amount have settled on the bottom surface of the container.

The hollow silica particles preferably do not settle to decamethylcyclopentasiloxane at 25 ° C.
Thus, it can confirm that the silica of the outer shell of a hollow silica particle does not permeate | transmit decamethylcyclopentasiloxane, when a hollow silica particle does not settle in decamethylcyclopentasiloxane.
Decamethylcyclopentasiloxane simulates sebum. Since decamethylcyclopentasiloxane does not permeate silica, it can be confirmed that sebum does not penetrate into the hollow portion of the hollow silica particles when the hollow silica particles are applied to the skin.
When sebum permeates into the hollow part of the hollow silica particles, the irregular reflection effect of light as the hollow particles may be reduced. Therefore, it is preferable that the hollow silica particles prevent permeation of sebum without passing through decamethylcyclopentasiloxane.

  Here, the fact that the hollow silica particles do not settle to decamethylcyclopentasiloxane under the above conditions is that at 25 ° C., the hollow silica particles are added from the top of decamethylcyclopentasiloxane having a depth of 3 cm from the liquid surface to the bottom surface, It is in a state where it can be visually confirmed that the amount of hollow silica particles precipitated on the bottom surface of the container is 30% by mass or less of the charged amount when allowed to stand for 24 hours without stirring. At this time, particles that are not precipitated may be dispersed in the liquid or may be suspended.

The hollow silica particles are preferably not precipitated in water at 25 ° C.
Thus, it can confirm that the silica of the outer shell of a hollow silica particle does not permeate | transmit water because a hollow silica particle does not settle in water.
When moisture permeates into the hollow part of the hollow silica particle as sweat or the like, the irregular reflection effect of light as the hollow particle may be lowered. Therefore, it is preferable that the hollow silica particles prevent moisture penetration.

Here, the fact that the hollow silica particles do not settle in water under the above conditions is that at 25 ° C., the hollow silica particles are added from the top of the water having a depth of 3 cm from the liquid surface to the bottom surface, and left for 24 hours without stirring. In this case, it can be visually confirmed that the amount of the hollow silica particles precipitated on the bottom surface of the container is 30% by mass or less of the charged amount.
The state where precipitation does not occur is a state where the dispersion is cloudy or a state where particles are suspended in the dispersion.

The hollow silica particles are preferably precipitated in ethanol and not precipitated in decamethylcyclopentasiloxane under the above-described conditions.
As a result, when the cosmetic is stored, the hollow silica particles are settled in a volatile solvent such as ethanol, so that the cosmetic with a uniform composition can be taken out by gently shaking the container. It becomes. After the cosmetic is applied to the skin, ethanol or the like evaporates in the hollow silica particles, but thereafter, sebum can be prevented from entering the hollow portions of the hollow silica particles, thereby preventing deterioration of optical properties. .
Furthermore, since the hollow silica particles settle in ethanol and do not settle in decamethylcyclopentasiloxane and water, it is possible to further prevent optical properties from being deteriorated by moisture such as sweat.

<Method for producing hollow silica particles>
Next, an example of a method for producing hollow silica particles will be described.
The hollow silica particles according to the present embodiment are manufactured by, for example, producing core-shell type particles whose inner core is a core particle and outer shell is SiO ₂ and removing the core particle from the core-shell type particle. Can do. In addition, the hollow silica particle by this embodiment is not limited to what was manufactured by this manufacturing method.

(Core particles)
As the core particles, those that are dissolved, decomposed or sublimated by heat, acid, or light and removed while leaving the outer shell silica can be preferably used.
Examples of the core particles include thermally decomposable organic polymer particles such as surfactant micelles, water-soluble organic polymers, styrene resins, and acrylic resins; acids such as sodium aluminate, calcium carbonate, basic zinc carbonate, and zinc oxide. Soluble inorganic particles: one or a mixture of two or more selected from metal chalcogenide semiconductors such as zinc sulfide and cadmium sulfide, and light-soluble inorganic particles such as zinc oxide can be used.

  Since the particle shape of the core particles affects the final shape of the hollow silica particles, it is preferably determined according to the particle shape of the target hollow silica particles. Examples of the particle shape of the core particle include a spherical shape, a cubic shape, a rugby ball shape, a spindle shape, a rod shape, an amorphous shape, a columnar shape, a needle shape, a flat shape, a scale shape, a leaf shape, a tube shape, a sheet shape, and the like. Can be mentioned.

  The average particle diameter and particle size distribution of the core particles are preferably substantially the same as the target hollow silica particles.

The core particles are preferably used as a dispersion.
Various methods can be employed to disperse the core particles in the dispersion medium. For example, a method of synthesizing in a solvent, a ball mill, a sand mill by adding a dispersion medium and a dispersant as described later to the core particle powder. And a method of peptizing with a dispersing machine such as a homomixer or a paint shaker.
The solid content concentration of the core particle dispersion is preferably in the range of 50% by mass or less. If the solid content concentration exceeds 50% by mass, the stability of the dispersion is lowered, which is not preferable.

(Silica precursor)
In order to obtain hollow silica particles, first, core-shell type particles whose outer shell is silica are produced.

  Specifically, the surface of the core particle is made to react by reacting the core particle or the raw material of the core particle with the silica precursor, or by causing the silica precursor to decompose in the presence of the core particle. By depositing and forming the outer shell, core-shell type particles can be obtained. Thus, the liquid phase method can be used as a method for producing the core-shell type particles.

  In the liquid phase method, the silica precursor is hydrolyzed by adding a hydrolysis catalyst such as acid or alkali in the presence of the core particles, and silica is deposited around the core particles (outer surface). Can do. The silica precursor is easily polymerized three-dimensionally under alkaline conditions to form a shell. That is, the higher the pH, the faster the hydrolysis / polycondensation reaction rate of the silicon compound such as the silica precursor, so that the silica shell can be formed in a short time. Therefore, the pH of the solution is 7 or more, more preferably pH 8 or more, most preferably pH = 9 to 11. A pH exceeding 11 is not preferable because the hydrolysis rate is too high and the silica itself produced is agglomerated, making it difficult to form a homogeneous outer shell on the outer surface of the core particles. Further, the core-shell type particles having the formed silica outer shell can be further aged by applying heat to make the outer shell denser.

Examples of the silica precursor include one or a mixture of two or more selected from silicic acid, silicate, and silicate ester, and may be a hydrolyzate or polycondensate thereof.
Specifically, as silicic acid, alkali metal silicate is decomposed with acid and then dialyzed, alkali metal silicate is peptized, and alkali metal silicate is converted into an acid-type cation exchange resin. Examples thereof include silicic acid obtained by a contact method.
Examples of the silicate include alkali silicates such as sodium silicate and potassium silicate, quaternary ammonium salts such as ammonium silicate and tetraethylammonium salt, and silicates such as amines such as ethanolamine.
Examples of the silicate ester include tetramethoxysilane, tetraethoxysilane (TEOS), methyltrimethoxysilane, tetrapropoxysilane, dimethoxydimethylsilane, and diethoxydimethylsilane. Moreover, the hydrolyzate and polycondensate of these silicate esters can be used.

  In the case where acid-soluble inorganic particles such as calcium carbonate are used as the core particles, the pH is preferably 8 or more from the viewpoint of preventing dissolution of the core particles during the silica coating reaction.

(Dispersion medium)
When the core-shell type particle dispersion is produced by the liquid phase method, the dispersion medium in which the core particles are dispersed and the decomposition reaction of the silica precursor is performed is not particularly limited. For example, water; methanol , Ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, ethylene glycol, polyethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, cyclopentanol, cyclopentane Alcohols such as diol and cyclohexanol;
Ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl propyl ketone, isopropyl methyl ketone, isobutyl methyl ketone, cyclopentanone, cyclohexanone, acetophenone;
Ethers such as glyme, diglyme, isopropyl ether, isobutyl ether, methyl isopropyl ether, anisole, tetrahydrofuran, and dioxane;
Esters such as methyl acetate, ethyl acetate, ethyl acetoacetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate;
Glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether;
Including N, N-dimethylacetamide, N-methylacetamide, N, N-dimethylformamide, N-methylformamide, 2-pyrrolidinone, N-methyl-2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, etc. Nitrogen compounds;
Sulfur-containing compounds such as dimethyl sulfoxide and sulfolane can be used.
These may be used alone or in combination of two or more.

  However, in the process of hydrolyzing and polycondensing the silica precursor to form the outer shell, the presence of water is essential, and therefore it is preferable to contain 5 to 100% by mass of water in all the solvents. If the water content is less than 5% by mass, the reaction does not proceed sufficiently. In addition, it is preferable that at least the stoichiometric amount of water is present in the system with respect to the amount of Si in the silica precursor in the dispersion medium.

  Further, the solid content concentration in producing the core-shell type particle dispersion is preferably in the range of 30% by mass or less and 0.1% by mass or more, and in the range of 20% by mass or less, 1% by mass or more. More preferably. If it exceeds 30% by mass, the stability of the particle dispersion decreases, so this is not preferred, and if it is less than 0.1% by mass, the productivity of the resulting hollow silica particles becomes very low, which is not preferred.

  In addition, when producing the core-shell type particle dispersion, in order to increase the ionic strength and facilitate the formation of a shell from the silica precursor, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, sodium nitrate, potassium nitrate, Electrolytes such as lithium nitrate, calcium nitrate, magnesium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, ammonia, ammonium hydroxide, sodium hydroxide, potassium hydroxide, and magnesium hydroxide may be added, and these electrolytes Can be used to adjust the pH.

(Removal of core particles)
Next, hollow silica particles can be obtained by removing the core particles from the core-shell type particles.

  As a method for removing the core particle from the core particle of the core-shell type particle, one or more methods selected from thermal decomposition, acid decomposition, and light decomposition are used according to the type of the core particle. be able to.

When the core particle is a thermally decomposable organic resin, the core particle can be removed by heating in a gas phase or a liquid phase. The heating temperature is preferably in the range of 200 to 1000 ° C. If it is less than 200 ° C., the core particles may remain, and if it exceeds 1000 ° C., SiO ₂ may be melted, which is not preferable.

When the core particles are acid-soluble inorganic compounds, the core particles can be removed by adding an acid or acidic cation exchange resin in the liquid phase.
The acid is not particularly limited, and may be an inorganic acid or an organic acid. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, carbonic acid, phosphoric acid, phosphorous acid, hypophosphorous acid, nitrous acid, and the like. Examples of organic acids include formic acid, acetic acid, propionic acid, butyric acid, Examples include herbic acid, caproic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, malic acid, tartaric acid, citric acid, lactic acid, gluconic acid, maleic acid, fumaric acid, and succinic acid.

The acidic cation exchange resin may be a polyacrylic resin-based or polymethacrylic resin-based one having a carboxylic acid group, but a polystyrene-based one having a more strongly acidic sulfonic acid group is more preferable.
In addition, when using an acid-soluble inorganic compound as a core particle, it is preferable to set it as pH 5 or less at a removal process.

  When the core particle is a photosoluble inorganic compound, the core particle can be removed by irradiating light in a liquid phase. The wavelength of light is preferably 380 nm or less, which has higher energy.

  After removing the core particles from the core-shell type particles, it is preferable to wash the hollow silica particles. The washing can be performed using a solvent such as methanol, ethanol, acetone or the like. After washing, the solvent can be removed by drying to obtain hollow particles.

The hollow silica particles may be fired as necessary after washing and drying.
The firing temperature is preferably 100 to 800 ° C, and more preferably 100 to 500 ° C.
By firing, the outer shell of silica is densified, and the organic components in the silica outer shell can be removed. It is also possible to subject the silica outer shell only to a hydrophobic treatment with a surface treatment agent such as a silane coupling agent or silicone oil after firing.

On the other hand, the hollow silica particles can be provided in a washed and dried state without firing.
When the hollow silica particles are fired at a high temperature of 200 ° C. or higher, high energy is required, and the hollow silica particles may aggregate. Moreover, the organic component introduced into the outer shell in the silica coating step may disappear, leading to a decrease in the carbon ratio.
By not firing, the feel of the hollow silica particles can be made smoother. Moreover, by not baking, water repellency can be obtained leaving the organic component of the raw material.

  In the above method, whether or not the core particles have been removed from the core-shell type particles should be confirmed by observing the particles with a scanning electron microscope after crushing or by performing elemental analysis of the obtained particles. Can do.

<Cosmetics>
The cosmetic material according to this embodiment is characterized by containing the above-described hollow silica particles.
Cosmetics containing the hollow silica particles described above,
Make-up cosmetics such as powder foundation, cream foundation, oily foundation, amphibious foundation, powdered white powder, blusher, eye shadow, eyebrow;
Body cosmetics such as body powder / cream and baby powder / cream;
It can be used as skin cosmetics such as skin lotion, milky lotion and sunscreen agent.

If necessary, the cosmetic can be appropriately blended with other components blended in a normal cosmetic within a range not impairing the effects of the present invention.
As other ingredients, for example,
Solid or semi-solid oils such as petrolatum, lanolin, ceresin, microcrystalline wax, carnauba wax, candelilla wax, higher fatty acids, higher alcohols;
Fluid oils such as squalane, liquid paraffin, ester oil, diglyceride, triglyceride, silicone oil;
Fluorinated oils such as perfluoropolyether, perfluorodecalin, perfluorooctane;
Water-soluble or oil-soluble polymers; surfactants;
Coloring agents such as inorganic or organic pigments, tar pigments, natural pigments;
Ethanol, preservatives, antioxidants, pigments, thickeners, pH regulators, fragrances, UV absorbers, moisturizers, blood circulation promoters, cold agents, antiperspirants, bactericides, skin activators, water, etc. One kind or a combination of two or more kinds can be used.
What is necessary is just to adjust the compounding quantity of the hollow silica particle in cosmetics suitably according to the dosage form of cosmetics.

Hereinafter, the present invention will be described using examples. In addition, this invention is not limited to the following illustrations.
Table 1 shows the evaluation results of Examples and Comparative Examples.

Example 1
(1) 480 g of ethanol, 320 g of water, 200 g of spherical calcium carbonate (“Karumaru SCS” manufactured by Sakai Chemical Industry Co., Ltd.), 178 g of tetraethoxysilane (TEOS), and 29.1 g of methyltrimethoxysilane are mixed. Thereafter, an aqueous ammonia solution was added to adjust the pH to 10, followed by stirring at 30 ° C. for 6 hours to obtain a silica-coated calcium carbonate dispersion. This dispersion is in the form of a core-shell type particle dispersion.

(2) To the obtained silica-coated calcium carbonate dispersion, 4000 ml of a strongly acidic cation exchange resin (“Diaion” manufactured by Mitsubishi Chemical Corporation, total exchange capacity of 2.0 (meq / ml) or more) is added and stirred for 5 hours. Then, after reaching pH = 4, the strong acidic cation exchange resin was removed by filtration to remove the spherical calcium carbonate, and a hollow silica particle dispersion containing hollow SiO ₂ was obtained.

  (3) The hollow silica particle dispersion was filtered, washed with ethanol, and dried at 100 ° C. to obtain hollow silica particles.

(Evaluation)
When the average particle diameter of the obtained hollow silica particles was determined by a laser scattering method, it was 2.1 μm. The thickness of the outer shell was 120 nm. Moreover, the shape of all the particles was spherical. The carbon ratio was 4% by mass.
The hollow silica particles settled when added to ethanol, and floated when added to decamethylcyclopentasiloxane. It also floated in the water.
The evaluation of optical properties of the coating film of Example 1 was a haze value of 80.0% and a total light transmittance of 83.1%. The particle strength was 29.3 MPa.

The obtained hollow silica particles were evaluated according to the following.
(1) The average particle diameter of the hollow silica particles was measured with a laser scattering particle size analyzer (“MICROTRAC HRA DHSX100” manufactured by Nikkiso Co., Ltd.) after dispersing the particles in ethanol.
(2) The thickness of the outer shell of the hollow silica particles was observed with a scanning electron microscope. After obtaining a cross-section using a cross-section sample measuring apparatus (“Cross Section Polisher” manufactured by JEOL Ltd.), the particle size was adjusted to 1.1-3. The thickness of the outer shell was measured for any 5 grains of 2 μm, and the average value was determined. The particle shape was also confirmed by a scanning electron microscope.
(3) The carbon content of the hollow silica particles was determined by burning a small amount of sample in a furnace heated to 1000 ° C., mass analyzing the amount of carbon dioxide produced, and measuring the amount of carbon. As the mass spectrometer, “2400II, CHN meter” manufactured by PerkinElmer was used.

(4) Sedimentation in solvent The hollow silica particles settled in ethanol. At 25 ° C, the hollow silica particles were added from the top of ethanol with a depth of 3 cm from the liquid surface to the bottom, and stirred under atmospheric pressure. After standing still for 1 hour, it was confirmed by visual observation that all the hollow silica particles were precipitated on the bottom of the container.
The fact that the hollow silica particles do not settle on the decamethylcyclopentasiloxane is that, at 25 ° C., the hollow silica particles are added from the top of the decamethylcyclopentasiloxane having a depth of 3 cm from the liquid surface to the bottom surface, and are not stirred for 24 hours. After standing, it was confirmed by visual observation that the hollow silica particles were precipitated only about 10% by mass of the total amount on the bottom of the container.
The fact that the hollow silica particles do not settle in water is that the hollow silica particles are added from the top of the water having a depth of 3 cm from the liquid surface to the bottom surface at 25 ° C., and left to stand for 24 hours without stirring. It was confirmed by visual observation that silica particles were not precipitated on the bottom of the container.

(5) Optical property measurement method 0.45 g of silicone (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-7312J) which is a mixture of 50% trimethylsiloxysilicic acid and 50% decamethylcyclopentasiloxane, and hollow silica particles 0 .05 g, and then using a spin coater (trade name: ACT-300A, manufactured by Active Co., Ltd.), a coating film thickness is formed on a PET film (trade name: IT-125PF, made by PLUS) having a thickness of 0.1 mm. A film was formed to a thickness of 30 μm and dried at 50 ° C. for 30 minutes to obtain a coating film for measuring optical properties. The haze value and total light transmittance were measured with a haze meter. The value of a coating film produced only with silicone (KF-7312J) without silica particles was used as a reference.
(6) The particle strength was measured by a micro compression tester (MCTM-500 type) manufactured by Shimadzu Corporation.

(Example 2)
(1) 480 g of ethanol, 320 g of water, 200 g of spherical calcium carbonate having an average particle size of 5 μm (“Karumaru SCS” manufactured by Sakai Chemical Industry Co., Ltd.), 68 g of tetraethoxysilane, and 14 g of dimethoxydimethylsilane are added, and then an aqueous ammonia solution is added. The mixture was adjusted to pH = 10 and stirred at 30 ° C. for 6 hours. Thereafter, 10 g of hexamethyldisilazane was added and stirred at 30 ° C. for 1 hour.

  (2) Hydrochloric acid was slowly added to the obtained silica-coated calcium carbonate dispersion to dissolve calcium carbonate. Subsequently, the filter was washed with an ethanol solution containing 30% by mass of water and 0.1% by mass of hexamethyldisilazane. The obtained cake was dried under reduced pressure at 100 ° C. to obtain hollow silica particles.

It was 5 micrometers when the average particle diameter of the obtained hollow silica particle was calculated | required with the laser scattering method. The thickness of the outer shell was 150 nm. Moreover, the shape of all the particles was spherical. The carbon ratio was 11.1% by mass.
The hollow silica particles settled when added to ethanol, and floated when added to decamethylcyclopentasiloxane.
The optical properties of the coating film of Example 2 were evaluated as having a haze value of 79.5% and a total light transmittance of 82.8%. The particle strength was 26.1 MPa.

(Example 3)
Calcium carbonate fine particles were dispersed in a liquid of water / ethanol = 50%, and a dispersion having an average particle size of 0.19 μm and a solid content concentration of 20% by mass was obtained using a bead mill. While thoroughly stirring 336 g of this dispersion, 491 g of water and 506 g of ethanol were added to the dispersion, and the dispersion was heated to 30 ° C. Next, the pH of this dispersion was adjusted to 9.5 using 28% by mass ammonia water (manufactured by Kanto Chemical Co., Ltd.), and then the tetraethoxysilane (manufactured by Kanto Chemical Co., Ltd.) was added to the dispersion while stirring the dispersion. Of 29.0 g was added. Next, the dispersion is stirred for 8 hours while adding 28% by mass of ammonia water (manufactured by Kanto Chemical Co., Inc.) so that the pH of the dispersion becomes 9.4 to 9.6, thereby hydrolyzing TEOS Then, silica was deposited on the surface of the calcium carbonate particles. Next, after 90 g of this dispersion was heated to 60 ° C., 22.6 g of tetraethoxysilane (manufactured by Kanto Chemical Co., Inc.) and isobutyltrimethoxysilane (manufactured by Toray Dow Corning Silicone, AY 43-048) were added to the dispersion. 2.8 g) was added almost simultaneously. The dispersion is stirred for 20 minutes while adding 1N ammonia water (manufactured by Kanto Chemical Co., Inc.) to the dispersion so that the pH of the dispersion is 9.5 to 9.6, and tetraethoxysilane and isobutyltrimethoxysilane. Was hydrolyzed.

To the resulting silica-coated calcium carbonate dispersion, 4000 ml of a strongly acidic cation exchange resin (“Diaion” manufactured by Mitsubishi Chemical Corporation, total exchange capacity of 2.0 (meq / ml) or more) is added, and a 50 wt% ethanol water mixture is added. After adding 4000 ml of the mixture and stirring for 5 hours to reach pH = 4, the strong acidic cation exchange resin is removed by filtration to remove the spherical calcium carbonate, and the hollow silica particle dispersion containing hollow SiO ₂ Got.
To this dispersion, 20 g of hexamethyldisilazane (GE Toshiba Silicone, TSL8802) was added, and the dispersion was stirred for 1 hour.
This dispersion was dried by spray drying to obtain hollow silica particle powder.
The particle size of the hollow particles was measured by a laser scattering method (manufactured by Nikkiso Co., Ltd., Microtrac 9340UPA) after being dispersed in methanol and subjected to ultrasonic treatment. The average particle size was 0.19 μm. Moreover, the average value of the thickness of the outer shell measured with arbitrary five particles was 11 nm. The carbon ratio was 5%.
The hollow silica particles settled when added to ethanol, and floated when added to decamethylcyclopentasiloxane.
The optical properties of the coating film of Example 3 were evaluated as having a haze value of 76.5% and a total light transmittance of 83.1%.

(Comparative Example 1)
A non-hollow spherical porous silica particle having an average particle size of 2.9 μm (“Sunsphere H32” manufactured by AGC S-Tech Co., Ltd.) was subjected to a sedimentation test in ethanol, decamethylcyclopentasiloxane, and water. As a result, it settled in any case. Moreover, the optical characteristic evaluation of the coating film was haze value 18.5% and total light transmittance 98.4%.

(Comparative Example 2)
Non-hollow spherical solid silica particles having an average particle diameter of 4.5 μm (“Sunsphere NP30” manufactured by AGC S-Tech) were evaluated in the same manner as in Comparative Example 1 described above. As a result, it precipitated in all of ethanol, decamethylcyclopentasiloxane, and water. Moreover, the optical characteristic evaluation of the coating film was haze value 41.4% and total light transmittance 99.9%.

As shown in Table 1, in Examples 1 and 2, hollow silica particles were used, and from the results of haze value and total light transmittance, a coating film having high shielding rate and excellent light scattering performance was obtained.
Moreover, in Examples 1 and 2, it settled in ethanol, but floated without precipitating in decamethylcyclopentasiloxane and water. Thus, the hollow silica particles of Examples 1 and 2 are easy to store in ethanol as a cosmetic composition, and after being applied to the skin, the ethanol in the hollow silica particles evaporates and remains hollow, sebum. It can be seen that moisture such as water and sweat is prevented from entering.

In Comparative Example 1, spherical porous silica particles were used, and sufficient optical characteristics were not obtained. Further, in Comparative Example 1, since the porous silica particles settle in decamethylcyclopentasiloxane and water, the porous silica particles are eroded by moisture such as sebum and sweat after being applied to the skin, and sufficient light It is thought that scattering characteristics cannot be obtained.
In Comparative Example 2, spherical solid silica particles were used, and sufficient optical characteristics were not obtained. In Comparative Example 2, since solid silica particles settle in decamethylcyclopentasiloxane and water, the porous silica particles are eroded by moisture such as sebum and sweat after being applied to the skin, and sufficient light is applied. It is thought that scattering characteristics cannot be obtained.

Moreover, the lightness at the time of apply | coating the dried powder to a fingertip and the back of a hand was evaluated. There were 10 subjects, and the most common criterion was the evaluation result. The evaluation results are also shown in Table 1.
The evaluation criteria are as follows.
Based on the evaluation result of the solid silica particles of Comparative Example 2, the evaluation was made according to four criteria of very light, light, heavy and very heavy.

The hollow silica particles of Examples 1 and 2 were very light in comparison with the porous silica particles of Comparative Example 1 and the solid silica particles of Comparative Example 2.

Claims (6)

  A cosmetic comprising hollow silica particles having an average particle diameter of 0.1 μm or more and 30 μm or less and an outer shell thickness of 5 nm or more and 500 nm or less.   The cosmetic according to claim 1, wherein the carbon content of the hollow silica particles is 3% by mass or more.   When a coating film having a thickness of 30 μm was prepared using a composition containing 20% by mass of the hollow silica particles in trimethylsiloxysilicic acid, the coating film containing no hollow silica particles The cosmetic according to claim 1 or 2, having a haze value of 50% or more and a total light transmittance of 90% or less.   The cosmetic according to any one of claims 1 to 3, wherein the strength of the hollow silica particles is 3 MPa or more.   The cosmetic according to any one of claims 1 to 4, wherein the hollow silica particles are spherical. When the hollow silica particles are added to ethanol at 25 ° C., the precipitation amount of the hollow silica is 70% by mass or more of the input amount, and when the hollow silica particles are added to decamethylcyclopentasiloxane, the hollow silica particles The cosmetic according to any one of claims 1 to 5, wherein a precipitation amount of is 30% by mass or less of an input amount.