JP3455066B2 - UV reflective powder and cosmetic containing it - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a monodisperse powder having high transparency and an excellent UV protection effect, and a cosmetic containing the same.

[0002]

2. Description of the Related Art Conventionally, sunscreen cosmetics have used inorganic powders or organic ultraviolet absorbers as UV screening agents. Among these, as the inorganic powder, for example, zinc oxide, titanium oxide, cerium oxide, etc. are used,
Ultraviolet rays are shielded by utilizing absorption or light scattering peculiar to powder. Further, an organic compound having an absorption characteristic in the UV wavelength range is used as an organic ultraviolet absorber.

Further, the fine particle powder used as a UV cosmetic base material is not uniform in particle size or is an agglomerate of secondary particles, so that the hiding rate on the skin is low, which is expected. You cannot get the desired UV protection effect. As a result, at the level of powder required to obtain a high UV shielding effect (SPF level), there is a heavy and unpleasant feeling of use,
It also results in a white / blue residue on the skin. In particular, metal oxide powders, which are widely used as sunscreens for cosmetics, have extremely large cohesive force and are prone to cause such problems.

Further, in the conventional sunscreen cosmetics, emphasis is placed on the protection of UVB light (280 nm to 320 nm), which causes large damage to the skin (sunburn, skin cancer, photoaging), and the SPF value (Sun protect) is higher.
Products with high ion factors have been developed. In recent years, photoaging of UVA light (320 nm to 400 nm),
The effect on skin cancer is also regarded as a problem, and the PFA value (pr
Cosmetics with a high insulation factor of UVA) are being developed and commercialized. However, the wavelength of the reflected / absorbed light of the powder is peculiar, and few of them have the reflection / absorption characteristics of UVA light, so organic UV absorbers have been developed as UVA light absorbers. However, it is not possible to add a high concentration because of problems such as stability, irritation to the skin, etc.

On the other hand, it has long been known that light is diffracted when light is incident on the ordered structure layer formed of the monodisperse particle powder. For example, the diameter is 0.15 μm to 0.40 μ
When spherical monodisperse particles of m 3 form a regular structure, the surface of the particle layer emits monochromatic light having a vivid metallic luster due to the diffraction of visible light. In this coloring phenomenon, it is important that the monodisperse particles are regularly arranged, and the material thereof is not particularly limited. Therefore, it is important to select a material having excellent stability as the material of the monodisperse particles.

When monodispersed particle powder forms a regular structure layer in the form of a crystal lattice with a surface spacing of d, and light is vertically incident on this particle layer, the light is diffracted similarly to the X-ray diffraction of crystals. Happened,

[0007]

[Formula 1] λ = 2n · d (1)

Light having a wavelength λ satisfying the above condition is reflected most strongly. Here, n is the refractive index of the particles in the particle layer of light. d changes depending on the arrangement of the monodisperse particles,
If the arrangement is the same, it is proportional to the size (particle size) of the particles. For example, when spherical monodisperse particles having a diameter D are arranged in a face-centered cubic lattice pattern and the (1, 1, 1) plane appears on the surface of the particle layer, d is

[0009]

[Equation 2]

Among the powders used as a raw material for cosmetics, there are few monodisperse particles having a uniform particle size, and there is no example in which the above diffraction phenomenon is applied to UV cosmetics.

[0011]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a monodisperse powder having high transparency and excellent UV protection effect.

[0012]

Under these circumstances, the inventors of the present invention have conducted diligent research, and as a result, found that a monodisperse powder that forms a regular structure and has UV selective reflectivity when applied. By having high transparency and excellent UV protection effect, and changing the particle size of the monodisperse powder,
The inventors have found that the wavelength of the diffracted and reflected light observed when a regular structure is formed can be changed, and that light from UVB to UVA can be selectively and strongly reflected, thus completing the present invention.

That is, in the present invention, the average particle size measured by the dynamic light scattering method is 0.147 to 0.25 μm, and the particle size distribution (weight average particle size / number average particle size) is 1. ．
50 or less, having formed vital UV selective reflectivity regular structure when coated, UV reflecting powders of polymer particles child or Ranaru monodisperse powder, and containing the same makeup The fee is provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The monodisperse powder of the present invention, when applied, first forms a regular structure. Here, coating means applying a dispersion liquid of monodisperse powder to a solid surface, particularly to the skin surface to evaporate a volatile dispersion medium. At this time, the regular structure formed by the powder means a crystal lattice-like structure formed when the uniform powder is filled, and it is preferable that the regular structure layer emits reflected diffracted light. . Such a regular structure can be confirmed by, for example, measuring a reflection spectrum.

Further, in the monodisperse powder of the present invention, the regular structure formed by coating has UV selective reflectivity. Here, the UV selective reflectivity has a wavelength of 25
Those capable of reflecting light in the UVA range from 0 to 400 nm are preferable. The reflected light due to the ordered structure of the monodisperse particle powder can be measured by applying the powder dispersion liquid onto a glass plate and using the apparatus shown in FIG. Further, the wavelength of the reflected light can be changed by adjusting the particle size of the powder and controlling the surface spacing of the regular structure layer. That is, as the particle size is smaller, the intensity peak of the reflected light shifts to the shorter wavelength side.

The transmitted light of the monodisperse powder can be measured by using a spectrophotometer after forming the powder dispersion liquid on a quartz plate to a thickness of 0.1 mm. The transmittance in the visible region reflects the transparency of the powder, and it is preferable that the transmittance is as high as possible, and the transmittance at a wavelength of 500 nm is preferably 70% or more. On the other hand, the transmittance of UV light having a wavelength of 250 to 400 nm is preferably low, and is preferably 50% or less.

In the monodisperse powder of the present invention, monodisperse means that the shape and size of individual particles are well aligned. The powder preferably has an average particle size measured by a dynamic light scattering method of 0.1 to 0.3 μm, particularly 0.15 to 0.25 μm, and a particle size distribution (weight average particle size / The number average particle size) is preferably 1.50 or less, and particularly preferably 1.10 or less. Within this range, a regular structure layer can be easily formed, and the UV reflection effect due to the structure becomes large, which is preferable. Furthermore, the particle shape is preferably spherical.

The material of the monodisperse powder of the present invention is not particularly limited, and may be any of inorganic powder, organic powder, and composite powder of these, such as titanium oxide, zinc oxide, cerium oxide, silica, sulfuric acid. Inorganic powder such as barium, alumina, aluminum hydroxide, calcium carbonate, magnesium silicate; polymer particles that can be prepared by emulsion polymerization, soap-free emulsion polymerization, suspension polymerization, dispersion polymerization, etc.
Examples thereof include composite particle powder in which the periphery of the inorganic powder is covered with a polymer (organic resin). Of these, composite particle powder obtained by coating inorganic powder with a polymer is particularly preferable.

As preferred monomers for use in preparing polymer particles, for example, styrene, vinyltoluene, divinylbenzene, ethylene, propylene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, (meth) acrylamide; (Meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, lauryl (meth) acrylate, oleyl (meth) acrylate, palmityl (meth) acrylate, stearyl ( (C1 to C20) of (meth) acrylic acid such as (meth) acrylate
Examples thereof include alkyl or (C3-C20) alkenyl esters.

Since the monodisperse powder of the present invention has high transparency and excellent UV protection effect, it can be suitably used as various cosmetic powders and the like. In this case, when the cosmetic is applied to the skin, the monodisperse powder forms a regular structure on the skin and can selectively reflect UV.

The cosmetic of the present invention preferably contains the monodisperse powder in an amount of 0.1 to 50% by weight, more preferably 0.1 to 25% by weight, and further preferably 1 to 20% by weight. This is preferable because it has high transparency and high UV reflection efficiency.

The cosmetic material of the present invention can be produced by a usual method except that the monodisperse powder is blended.
In order to further enhance the V reflectivity, other UV absorbers used in ordinary cosmetics may be appropriately blended within a range that does not impair the diffracted light by the ordered structure layer of the monodisperse particle powder.

The other UV absorber used here is not particularly limited, and any of the commonly used UV scattering agents, oil-soluble UV absorbers, and water-soluble UV absorbers can be preferably used. Among these, examples of the ultraviolet scattering agent include titanium oxide, fine particle titanium oxide (JP-A-57-67681), zinc oxide, fine zinc oxide (JP-A-62-228006), and flaky zinc oxide ( JP-A-1-175921), iron oxide, fine iron oxide, cerium oxide, zirconium oxide, and the like.
These may be surface-treated with silicone, metal soap, N-acyl glutamic acid, perfluoroalkyl phosphate ester, or the like. The shape, size and form of these are not particularly limited, and they may be used in the form of a sol or the like.

The oil-soluble UV absorbers include benzoic acid-based ones, such as para-aminobenzoic acid (hereinafter referred to as PA).
(Abbreviated as BA), glyceryl PABA, ethyldihydroxypropyl PABA, N-ethoxylate PABA ethyl ester, N-dimethyl PABA ethyl ester, N
-Dimethyl PABA butyl ester, N-dimethyl PA
BA amyl ester, octyl dimethyl PABA, etc .;
As anthranilic acid type, homomenthyl-N
-Acetylanthranilate and the like; as salicylic acid-based ones, amyl salicylate, menthyl salicylate,
Homomenthyl salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate, p-isopropanol phenyl salicylate and the like; cinnamic acid-based octyl cinnamate, ethyl-4-isopropyl cinnamate, Ethyl-2,4-diisopropylcinnamate, methyl-2,4-diisopropylcinnamate, propyl-p-methoxycinnamate, isopropyl-p-methoxycinnamate, isoamyl-p-
Methoxycinnamate, 2-ethylhexyl-p-methoxycinnamate, 2-ethoxyethyl-p-methoxycinnamate, cyclohexyl-p-methoxycinnamate, ethyl-α-cyano-β-phenylcinnamate, 2-ethylhexyl-α -Cyano-β-phenyl cinnamate, glyceryl mono-2-ethylhexanoyl diparamethoxy cinnamate and the like; benzophenone-based compounds such as 2,4-dihydroxybenzophenone,
2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2-hydroxy-4-methoxybenzophenone, 4-phenylbenzophenone, 2-ethylhexyl-4'-phenylbenzophenone-2-carboxylate, 2-hydroxy-4-n-octoxybenzophenone, 4-hydroxy-3-carboxybenzophenone, etc. Others: 3- (4'-methylbenzylidene) -dl-camphor, 3-benzylidene-dl-camphor, urocanic acid ethyl ester, 2
-Phenyl-5-methylbenzoxazole, 2,2'-
Hydroxy-5-methylphenylbenzotriazole,
2- (2'-hydroxy-5-t-octylphenyl)
Benzotriazole, dibenzalazine, dianisoylmethane, 4-methoxy-4'-t-butyldibenzoylmethane, 5- (3,3-dimethyl-2-norbornylidene)
-3-pentan-2-one, a benzene bis-1,3-diketone derivative described in JP-A-2-212579,
Examples thereof include benzoylpinacolone derivatives described in JP-A-3-220153.

As the water-soluble ultraviolet absorber, diethanolamine p-methoxycinnamate, sodium 2-hydroxy-4-methoxybenzophenone-5-sulfonate, tetrahydroxybenzophenone, methylherperidine, 3-hydroxy-4-methoxycinnamate. Examples thereof include sodium acidate, sodium ferulate, urocanic acid and the like, and extracts of animals and plants such as yarrow, aloe, biloba, burdock and salvia which have an ultraviolet absorbing effect.

Of these UV absorbers, cinnamic acid-based oil-soluble UV absorbers are particularly preferable.

When blending these UV absorbers,
It is preferable to add 0.1 to 50% by weight to the total composition,
In particular, it is preferable to add 0.5 to 20% by weight, and further 0.5 to 10% by weight, because a higher UV protection effect can be obtained.

In the cosmetic of the present invention, in addition to the above-mentioned components, various optional components used in ordinary cosmetics, quasi-drugs, pharmaceuticals, etc., as long as the effects of the present invention are not impaired.
For example, surfactants, oils, sterols, silicones, polysaccharides, amino acids, plant extracts, moisturizers, powders,
An oil gelling agent, a film-forming agent, an anti-inflammatory agent, an antioxidant, a pH adjusting agent, other components and the like can be appropriately added.

The cosmetic of the present invention is a W / O emulsion type, O / W
It can be in any dosage form such as emulsion type, gel type, solid state, liquid state, etc., for example, lotion, emulsion, cream, serum, etc., makeup cosmetics such as foundation, face powder, lipstick, etc. Can be

[0030]

The monodisperse powder of the present invention has high transparency,
Moreover, it has an excellent UV protection effect, and is particularly suitable as a compounding ingredient of cosmetics.

[0031]

EXAMPLES Next, the present invention will be further described with reference to examples, but the present invention is not limited to these examples.

The abbreviations used in the examples are as follows. St; styrene monomer NaSS; sodium styrenesulfonate APS; ammonium peroxodisulfate H ₂ O; distilled water

Example 1 (Production of Monodisperse Powder) The monodisperse polystyrene particles of the present invention were produced by soap-free emulsion polymerization. The composition of the monomer, the initiator, and the dispersion medium is: 40 parts St / 0.24 parts APS / 80 parts H ₂ O, and 0.08 parts, 0.12 parts, or 0.16 parts of NaSS should be added. The particle size was controlled by. Particle size and particle size distribution of the obtained polystyrene particles (weight average particle size /
Dynamic light scattering photometer (DLS-700;
It was determined by a dynamic light scattering method using Otsuka Electronics Co., Ltd.). The results are shown in Table 1.

[0034]

[Table 1]

Example 2 (Measurement of Reflected Light Spectrum) The monodisperse polystyrene particle dispersion obtained in Example 1 was
It was applied onto a glass plate and the reflected light spectrum was measured using the apparatus shown in FIG. The measurement result of the reflected light spectrum is shown in FIG. In FIG. 2, the horizontal axis represents the wavelength of light, and the vertical axis represents the intensity ratio of the reflected light from the sample when the intensity of the reflected light from the glass plate is 0 and the intensity of the reflected light from the barium sulfate plate is 100. Particle size is 206nm, 165nm, and 14
The 7 nm monodisperse polystyrene particles showed different reflected light spectrum charts, and the intensity peak of the reflected light was shifted to the shorter wavelength side as the particle size was smaller. On the other hand, in the case where the monodisperse polystyrene particles were dissolved in chloroform and the polystyrene film having no ordered structure layer was similarly coated on the glass plate, no specific reflected light peak was confirmed.

Example 3 (Measurement of transmitted light spectrum) The monodisperse polystyrene particle dispersion liquid obtained in Example 1 was
A film having a thickness of 0.1 mm was formed on a quartz plate, and the transmitted light spectrum was measured. The measurement result of the transmitted light spectrum is shown in FIG. In FIG. 3, the horizontal axis represents the wavelength of light and the vertical axis represents the transmittance. The transmitted light spectrum of the monodisperse polystyrene particles having a particle size of 165 nm has a low transmittance of about 40% at a wavelength of 400 nm and a high transmittance of about 80% at a wavelength of 500 nm.
It shows that it has UV reflectivity and high transparency. On the other hand, in the case where the monodisperse polystyrene particles were dissolved in chloroform and the polystyrene film having no ordered structure layer was similarly coated on the quartz plate, absorption of light having a wavelength of 300 nm or more was not confirmed.

Example 4 (Measurement of UV Protective Ability) Cosmetics having the compositions shown in Table 2 were produced by a conventional method, and the UV shielding effect of each cosmetic was measured by an SPF analyzer (SPF-290).
ANALYZER; The Optometrics
(Manufactured by Corporation). The results are also shown in Table 2.

[0038]

[Table 2]

As is clear from the results shown in Table 2, the cosmetic of the present invention had a high SPF value and an excellent UV protection effect. Also, the transparency was high.

[Brief description of drawings]

FIG. 1 is a diagram showing an apparatus used for measuring a reflected light spectrum in the present invention.

FIG. 2 is a diagram showing a reflected light spectrum of the monodisperse powder of the present invention measured in Example 2.

3 is a diagram showing a transmitted light spectrum of the monodisperse powder of the present invention measured in Example 3. FIG.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yama ▲ Saki ▼ Seiji Fumihana Sumida-ku, Tokyo 2-1-3 Kao Co., Ltd. Research Institute (56) Reference JP-A-5-58841 (JP, A) Kaihei 5-306314 (JP, A) JP 7-133232 (JP, A) JP 11-12148 (JP, A) JP 57-57260 (JP, A) JP 56-81319 ( JP, A) JP 59-179609 (JP, A) JP 7-315859 (JP, A) JP 9-77503 (JP, A) JP 5-221841 (JP, A) JP Hei 9-143030 (JP, A) JP 7-258058 (JP, A) JP 9-104822 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09K 3 / 00 104 A61K 7/42

Claims (5)

(57) [Claims] 1. An average particle size measured by a dynamic light scattering method is 0.147 to 0.25 μm, and a particle size distribution (weight average particle size / number average particle size) is 1.50 or less. there have formed vital UV selective reflectivity regular structure when applied, a polymer particle child or Ranaru monodisperse powder U
Powder for V reflection. 2. The UV reflecting powder according to claim 1, wherein the regular structure is a regular structure layer that emits reflected diffracted light. 3. The UV reflecting powder according to claim 1 or 2, which has a UV selective reflecting ability at a wavelength of 250 to 400 nm. 4. A regular structure is formed on the skin.
The powder for UV reflection according to any one of 1 to 3. 5. The UV according to any one of claims 1 to 4.
Cosmetics containing powder for reflection.