JPH09188611A - Surface-coated flaky powder, its production and cosmetic formulated therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject powder having high skin-protective effect against ultraviolet radiation of UVA region as well as that of UVB region, and to obtain a cosmetic good in spreadability, high in safety, and capable of giving natural makeup finish with no lurid luster by formulation of the powder. SOLUTION: The objective surface-coated flaky powder is obtained by coating the surface of cloven swellable stratified clay mineral 0.001-0.2μm in thickness and 30-100 in aspect ratio with a zinc oxide. Specifically, it is preferable to obtain the powder by coating the above clay mineral with a zinc salt hydrolyzate followed by baking at 300-700 deg.C to convert the hydrolyzate into the zinc oxide. The other objective cosmetic is obtained by formulation of the above powder. The cloven swellable stratified clay mineral is e.g. smectite, vermiculite, etc., being used either singly or in the combination of at least two of them. The coating proportion of the zinc oxide is >=80wt.% based on the whole flaky powder. Also, the coat may contain an ultraviolet absorber.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-coated flaky powder obtained by coating the surface of a cleaved swellable layered clay mineral having a specific particle shape with zinc oxide. For the body, medium wavelength (UV
The present invention provides a powder having an effect of protecting not only ultraviolet rays in the B) region but also ultraviolet rays in the long wavelength (UVA) region. Furthermore, the present invention relates to the production of a uniformly coated powder having a high UV protection effect in both the UVB and UVA regions, which is characterized in that zinc oxide is produced and coated on the surface of the cleaved swelling layered clay mineral. Further, by blending the surface-coated flaky powder, cosmetics having good dispersibility, smooth elongation on the skin, and a natural finish without blushing,
In particular, it relates to powder cosmetics. Further, the present invention relates to a cosmetic material which is excellent in ultraviolet absorbing effect and highly safe by using the surface-coated flaky powder and the ultraviolet absorbent together. Ultraviolet rays include UVB having a wavelength of 290 to 320 nm and UVA having a wavelength of 320 to 400 nm. It is said that UVA causes sagging of the skin, and UVB is involved in the formation of skin cancer and skin wrinkles (sunscreen agent and dermatology, Fragrance Journal, 1993). Recently, UVA is said to be involved in dermal damage and wrinkle formation. Therefore, various ultraviolet absorbers and ultraviolet protective powders have been studied for the purpose of protecting daily ultraviolet rays. For example, Japanese Patent Application Laid-Open No. 49-450 proposes that fine particle titanium dioxide is blended to provide a UV-preventing cosmetic composition. In addition, JP-A-62-228006
Proposes particulate zinc oxide as a substance capable of effectively blocking UVA around 360 nm. further,
Japanese Patent Application Laid-Open No. 61-257909 proposes an inorganic powder coated with a zinc-based material as a UV-screening pigment, and Japanese Patent Application Laid-Open No. 5-17329 discloses coating the surface of a scaly pigment with titanium oxide. A pigment composition in which zinc oxide is coated on the titanium oxide has been reported. Furthermore, attempts have been made to obtain a high UV protection ability by blending UV absorbers such as paradimethylaminobenzoate and oxybenzone. [0007] However, the ultraviolet shielding pigments and ultraviolet absorbers that have been proposed so far have the following problems and are not satisfactory. Absent. First, although fine particle titanium dioxide has an ultraviolet ray shielding effect, it has a small ultraviolet ray shielding effect in the UVA region of 350 nm or more. Furthermore, fine particle titanium dioxide, when blended in an amount that exerts an ultraviolet protection effect,
When applied to the skin, the elongation becomes heavy, and the bluish phenomenon that the finish becomes pale occurs. Fine zinc oxide capable of effectively blocking UVA around 360 nm, when incorporated into a cosmetic composition,
Poor dispersibility. Furthermore, when coating zinc oxide on another powder, it is difficult to coat it uniformly only by dry treatment.
There is a problem with the UV blocking effect. UVA and UVB can be obtained by coating zinc oxide and titanium oxide in combination.
Although they can both protect, there are drawbacks such that the covering power of titanium oxide increases, the finish becomes pale, and the elongation becomes heavy. Therefore, it was an object of the present invention to obtain a cosmetic which has a high UV protection effect and good elongation, is excellent in safety, and has a natural makeup finish without bluish light. Means, sericite, talc, kaolin and other conventionally used plate-like powders have been obtained by coating a cleaved swelling layered clay mineral as a core particle with zinc oxide. It is finer than the body, can coat a large amount of zinc oxide, and has good dispersibility when blended into cosmetics, has a high UV protection effect for both UVB and UVA, has good elongation, and has a blue glow. Therefore, they have found that a natural finish can be obtained, and have completed the present invention. That is, the present invention has a thickness of 0.001 to 0.
A surface-coated flaky powder obtained by coating the surface of a cleaved and swelling layered clay mineral having a size of 2 μm and an aspect ratio of 30 to 100 with zinc oxide, a method for producing the powder, and blending the powder. It relates to the characteristic cosmetics. The cleaved swelling layered clay mineral used in the present invention has a particle size of 0.001 to 0.001 in thickness.
It is a specific powder having a range of 0.2 μm and an aspect ratio of 30 to 100. Swelling layered clay minerals satisfying this condition include smectites and vermiculites, and these swelling layered clay minerals are used after being cleaved. Specific examples of the smectites used here include dioctahedral smectites such as nontronite, beidellite and montmorillonite, trioctahedral smectites such as saponite, and vermiculites such as trioctahedral vermiculite. To be Further, the origin of the cleaved swelling layered clay mineral may be synthetic or natural. In the present invention, the zinc oxide coating the surface of the cleaved swellable layered clay mineral means zinc oxide or hydrous zinc oxide. The zinc oxide with which the cleaved and swellable layered clay mineral is coated preferably has a particle size of 40 to 100 nm. The amount of zinc oxide coated on the cleaved swellable layered clay mineral is preferably 80% by weight or more in terms of ZnO, based on the entire surface-coated flaky powder. If it is less than 80% by weight, the required UV protection effect cannot be obtained. As a method for coating the cleaved swelling layered clay mineral with zinc oxide, various known methods such as a physicochemical mixed grinding method (dry method, wet method) and a chemical deposition method are selected. Although it is carried out, it is preferably produced by the following method from the viewpoint of coating uniformity and stability. By cleaving the cleaved swelling layered clay mineral with a hydrolysis product of a zinc salt and calcining at 300 to 700 ° C. to convert the hydrolysis product of the zinc salt into a zinc oxide, a surface-coated flaky material is obtained. Produce a powder. In the above description, the hydrolysis product of zinc salt means zinc hydroxide or hydrous zinc oxide, and the hydrolysis product of this zinc salt is calcined to obtain the surface of the cleaved swellable layered clay mineral. Zinc oxide is produced. The coating method of the hydrolysis product of the zinc salt on the cleaved swellable layered clay mineral is, for example, 60 to 90 by suspending the cleaved swellable layered clay mineral in a water-containing solvent.
An aqueous solution of a zinc salt is dropped into the solution while maintaining the pH at 7.5 to 10 with an alkaline aqueous solution by heating to 0 ° C., and the surface of the cleaved swelling layered clay mineral is coated with a hydrolysis product of the zinc salt. The surface-coated flaky powder of the present invention can be obtained by filtering, washing and drying the product, and calcining the product at 300 to 700 ° C. to convert the hydrolysis product of the zinc salt into zinc oxide. Further, as a method for coating the cleavage product of the hydrolysis product of the zinc salt on the cleaved swellable layered clay mineral, the cleaved swellable layered clay mineral is suspended in an aqueous solution of the zinc salt, and the mixture is added to 60-90.
The mixture is heated to ℃, and an aqueous alkali solution is added dropwise with stirring to coat the surface of the cleaved swellable layered clay mineral with a hydrolysis product of a zinc salt. After filtering, washing and drying this, 300-70
The surface-coated flaky powder of the present invention can also be obtained by calcining at 0 ° C. to convert the zinc salt hydrolysis product to zinc oxide. A water-containing solvent for suspending the cleaved and swelling layered clay mineral and an aqueous solution of a zinc salt may contain a pH adjusting agent, if necessary.
A dispersant, a dispersion aid, a viscosity modifier, etc. can be added. The ratio of the cleaved swellable layered clay mineral to the aqueous solution of the hydrous solvent and the zinc salt is preferably 10 to 300 g per 1 liter of the aqueous solution of the hydrous solvent and the zinc salt. Examples of the zinc salt used for coating the above zinc oxide include zinc sulfate, zinc chloride, zinc acetate and the like. As the alkali source of the alkaline aqueous solution, hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide, ammonia water, amines, urea and the like are used. Further, when the obtained surface-coated flaky powder is further coated with a hydrophobic compound such as a silicone compound, an organic fluorine compound, a higher fatty acid, a metal soap, a wax or a paste, it is blended in a cosmetic composition, Dispersibility and makeup retention are improved. When the surface-coated flaky powder is treated with the hydrophobic compound, the treatment may be carried out at the time of producing the powder or after mixing with other powder. When the surface-coated flaky powder is treated with the hydrophobic compound, the weight ratio of the surface-coated flaky powder to the hydrophobic compound is large because the surface-coated flaky powder has a large surface area. In order to perform the above treatment, it is necessary to treat at a ratio of 100/2 or more, preferably 100/4 or more. Further, the ultraviolet absorber used in combination with the surface-coated flaky powder is not particularly limited as long as it is an ultraviolet absorber which is usually blended in cosmetics. Specific examples include para-aminobenzoic acid esters such as ethyl paraaminobenzoate and ethylhexyl paradimethylaminobenzoate, and paramethoxybenzoic acid esters such as 2-ethoxyethyl para-methoxycinnamate and ethylhexyl paramethoxycinnamate. Ultraviolet (UVB) absorber, 4-t-butyl
Long wavelength ultraviolet (UVA) absorbers such as dibenzoylmethanes such as -4'-methoxybenzoylmethane and oxybenzones such as 2-hydroxy-4-methoxybenzophenone can be used. Further, the surface-coated flaky powder can be used in combination with other ultraviolet-protective powders such as fine particles of titanium oxide, zinc oxide, titanium oxide-coated powder, fine particles of iron oxide and the like. BEST MODE FOR CARRYING OUT THE INVENTION The surface-coated flaky powder thus obtained is incorporated into a cosmetic composition. The content in the cosmetic is preferably 0.1 to 50% by weight, more preferably 1 to 30% by weight. The cosmetics thus obtained are mainly makeup cosmetics such as liquid foundations, powder foundations, cake foundations, stick foundations, face powders, lipsticks, blushers, eye shadows and eyebrow pencils, and other body powders and cosmetics. Examples include a wide range of products such as sweat agents, sunscreen creams, sunscreen emulsions, whitening powders, emulsions and lotions. Among the above-mentioned cosmetics, among powdery cosmetics such as powder type or two-way type cake foundation, eye color, cheek color, highlight color, shadow color, powder white powder, solid white powder, etc. The effect of finishing the makeup is most remarkable, and it is most suitable as the cosmetic of the present invention. Further, when the makeup cosmetic is a powder solid cosmetic or an oily cosmetic, dispersibility is further improved by blending a surface-coated flaky powder treated with a hydrophobic compound. In addition, the makeup lasts longer. The combined use of the surface-coated flaky powder and the UV absorber synergistically improves the UV protection effect and is excellent in safety. EXAMPLES The present invention will be described in more detail with reference to examples. Example 1 Smectite treated with zinc oxide 20 g of smectite having an aspect ratio of 70 and a thickness of 0.07 μm was suspended and stirred in 1 liter of an aqueous solution of 1N zinc sulfate heptahydrate, heated to 80 ° C., and then 2N hydroxylated. A sodium aqueous solution (983 ml) was added dropwise over 90 minutes. Then filter this,
After washing with water, drying, crushing, and baking at 500 ° C. for 2 hours, 100 g of smectite whose surface was coated with zinc oxide was obtained. Example 2: Zinc oxide-treated montmorillonite 30 g of montmorillonite having an aspect ratio of 60 and a thickness of 0.1 μm is suspended in 500 ml of water and heated to 75 ° C.
With stirring, 1 liter of a 4N zinc chloride aqueous solution was added dropwise over 120 minutes. During this period, 1N potassium hydroxide was added dropwise to maintain the pH at 9. This was filtered, washed with water, dried, pulverized, and calcined at 450 ° C. for 3 hours to obtain 350 g of montmorillonite whose surface was coated with zinc oxide. Example 3: Silicone-coated zinc oxide-treated smectite 96 parts of the zinc oxide-treated smectite prepared in Example 1 and 4 parts of methyl hydrogen polysiloxane were mixed,
It was heated at 120 ° C. for 4 hours to obtain a silicone-coated zinc oxide-treated smectite. Comparative Example 1 A smectite 2 having an aspect ratio of 70 and a thickness of 0.07 μm
0 g and fine particle zinc oxide having a specific surface area of 70 m ² / g were treated with a vibrating ball mill for 120 minutes to obtain 100 g of zinc oxide-coated smectite. Comparative Example 2 Smectite having an average particle size of 5 μm and an aspect ratio of 6 was treated in the same manner as in Example 1 and then calcined to obtain 100 g of smectite whose surface was coated with zinc oxide. The ultraviolet protection effect of the surface-coated flaky powder of the present invention is evaluated by the SPF analyzer (SPF290ANALYZ.
ER: Optometrics USA, manufactured by Inc.). The measurement was performed using a transpore tape (Sumitomo 3M Limited) having a thin silicone film formed thereon, which was adhered onto a quartz plate, and a sample of 0.5 mg / cm ² was applied thereto using a brush. Example 1
The surface-coated flaky powders of Comparative Example 3 and Comparative Examples 1 and 2 were used as samples for measurement by the above-described apparatus and method, and the obtained SPF and average UVA protection index (UVAPF, Average UVA Protec
Table 1 shows the action factor). [Table 1] As shown in Table 1, Examples 1 to 3 of the present invention are shown.
It can be seen that the surface-coated flaky powder of No. 2 has a high value for both SPF and UVAPF and is excellent in the effect of protecting ultraviolet rays of both wavelengths in the UVB and UVA regions. On the other hand, in Comparative Example 1 in which zinc oxide and smectite were dry-processed and Comparative Example 2 in which smectite having a large particle size was coated with zinc oxide, both the SPF and UVAPF were half or less than those of the Examples. FIG. 1 shows the results of measuring the amount of transmission of ultraviolet rays of each wavelength using the SPF analyzer using the powder of Example 1 as a sample, and the reciprocal of the amount of transmission is expressed as MPF. Example 1 has a UVA region around 360 nm,
It has a maximum absorption near 320 nm in the UVB region and protects the skin from UV rays of both UVA and UVB wavelengths, and it is a highly transparent powder with almost no absorption in the visible region of 400 nm or more. Was done. Next, the powders of Examples 1 to 3 and Comparative Examples 1 and 2 were observed with a scanning electron microscope. As a result, in Examples 1 to 3, the surface of the cleaved swellable layered clay mineral was uniformly coated with zinc oxide. However, the powders of Comparative Examples 1 and 2 are those in which the surface of the cleaved swellable layered clay mineral is not uniformly coated with zinc oxide and zinc oxide, and the smectite surface is coated in multiple layers, In addition, zinc oxide and zinc oxide were released and partial aggregation was observed. Next, an example in which the powder according to the present invention and Examples 1 to 3 are blended in a cosmetic will be shown. Example 4: Powder foundation (1) Talc 10.0 (wt%) (2) Sericite 53.0 (3) Zinc oxide treated smectite (Example 1) 20.0 (4) Bengal 0.1. 7 (5) Yellow iron oxide 3.0 (6) Black iron oxide 0.3 (7) Squalane 13.0 Manufacturing method: After mixing the components (1) to (6) in a mixer and homogenizing
The component (7) is sprayed and further mixed. Then, after crushing through a crusher, it is filled in a gold plate and compression molded. Example 5 Two-Way Foundation (1) 2% Silicone Treated Talc 10.0 (wt%) (2) 2% Silicone Treated Sericite 52.8 (3) Silicone Coated Zinc Oxide Treated Smectite 20.0 ( Example 3) (4) 2% Silicone-treated red iron oxide 0.7 (5) 2% Silicone-treated yellow iron oxide 3.0 (6) 2% Silicone-treated black iron oxide 0.3 (7) Liquid paraffin 10.0 ( 8) 2-Ethylhexyl paramethoxycinnamate 3.0 (9) Methyl paraoxybenzoate 0.2 Manufacturing method: After (1) to (6) were mixed and homogenized with a mixer, (7) to (9)
The oil phase obtained by heating and dissolving the components of (1) is added, and the mixture is homogenized with a mixer. Then, after crushing through a crusher, it is filled in a gold plate and compression molded. Example 6: Solid white powder (1) Talc 50.0 (% by weight) (2) Sericite 36.6 (3) Zinc oxide treated montmorillonite (Example 2) 5.0 (4) Bengal 0.1. 2 (5) Yellow iron oxide 1.0 (6) Black iron oxide 0.1 (7) Magnesium stearate 2.0 (8) Squalane 3.5 (9) Isopropyl myristate 1.5 (10) Perfume 0. 1. Manufacturing method: After the components (1) to (7) are mixed and homogenized in a mixer, the homogenized components (8) to (10) are sprayed and further mixed. Then, after crushing through a crusher, it is filled in a gold plate and compression molded. Example 7: Stick-shaped foundation (1) Talc 20.0 (wt%) (2) Kaolin 10.0 (3) Zinc oxide treated montmorillonite (Example 2) 20.0 (4) Bengal 0.1. 7 (5) Yellow iron oxide 3.0 (6) Black iron oxide 0.3 (7) Liquid paraffin 16.9 (8) Isopropyl myristate 10.0 (9) Liquid lanolin 5.0 (10) Microcrystalline wax 5.0 (11) Beeswax 5.0 (12) Ethylhexyl paramethoxycinnamate 1.0 (13) 2-Hydroxy-4-methoxybenzophenone 1.0 (14) Sorbitan sesquioleate 2.0 (15) Paraoxybenzoic acid Propyl 0.1 Manufacturing method: The components (1) to (6) are mixed and homogenized with a mixer to obtain a powder phase. Separately, the components (7) to (15) are mixed and heated at 80 ° C. to obtain a melted oil phase. The above powder phase is added to the heated oil phase and kneaded with a roll mill. Heat the kneaded ones,
It is poured into a mold or container and cooled to be molded. Example 8: Sunscreen Emulsion (1) Beeswax 0.5 (wt%) (2) Vaseline 2.0 (3) Squalane 2.0 (4) Sorbitan Sesquioleate 0.8 (5) Sucrose Fatty acid ester 1.2 (6) Ethyl paraaminobenzoate 3.0 (7) Methyl paraoxybenzoate 0.1 (8) 1,3-Butylene glycol 5.0 (9) Sodium carboxymethylcellulose 1% aqueous solution 10.0 ( 10) Zinc oxide-treated smectite (Example 1) 10.0 (11) Purified water 62.2 (12) Ethanol 3.0 (13) Perfume 0.2 Production method: homogenize components (8) to (11). Pre-emulsify with a mixer,
Obtain an aqueous phase. The components (1) to (7) are heated and homogenized at 75 ° C., then added to the aqueous phase component heated at 75 ° C. and emulsified using a homomixer. After stirring and cooling to 40 ° C., the components (12) and (13) are added. Example 9: White powder (1) Talc 57.1 (wt%) (2) Sericite 35.0 (3) Zinc oxide treated montmorillonite (Example 2) 5.0 (4) Bengal 0.1. 2 (5) Yellow iron oxide 1.0 (6) Black iron oxide 0.1 (7) Squalane 1.5 (8) Perfume 0.1 Manufacturing method: Mix the components (1) to (6) in a mixer. After homogenizing, the homogenized components (7) and (8) are sprayed and further mixed. Then, after crushing through a crusher, it is passed through a sieve to obtain a product. Example 10: Water-in-oil type sunscreen cream (1) Beeswax 2.0 (% by weight) (2) Microcrystalline wax 1.0 (3) Lanolin 2.0 (4) Liquid paraffin 27.0 ( 5) Sorbitan sesquioleate 4.0 (6) Polyglyceryl monolaurate 1.0 (7) 2-Ethylhexyl paramethoxycinnamate 1.5 (8) 4-t-butyl-4'-methoxybenzoylmethane 1.5 (9) ) Methyl paraoxybenzoate 0.2 (10) Glycerin 8.0 (11) Smectite treated with zinc oxide (Example 1) 10.0 (12) Purified water 41.8 Process: Components of (10) to (12) With a homomixer,
Obtain an aqueous phase. The components (1) to (7) are heated to 75 [deg.] C. and homogenized, then the aqueous phase component heated to 75 [deg.] C. is added, and the mixture is emulsified using a homomixer. Cool to room temperature with stirring to obtain a water-in-oil type emulsion sunscreen cream. Furthermore, in order to show the ultraviolet protection effect in Examples 4 to 8 of the present invention, SunProtectio
n Factor (SPF) was measured. The SPF uses a xenon arc solar simulator as a light source, and uses 10 adult males as subjects to obtain the minimum erythema dose (MED) of the sample-uncoated area in advance, and then calculate the expected S of the sample.
Irradiation above the PF value is performed in 5 steps with a common ratio of 1.3, the MED of the sample application part is obtained, the value of the sample application part is divided by the value of the sample non-application part to calculate the SPF, and the average value of each subject Represented by At the same time, Comparative Examples 4 to 8 were prepared by mixing fine particle zinc oxide in place of the surface-coated flaky powder.
Table 2 shows the results. [Table 2] From Table 2, each of the examples is 1.5 to 5 of the comparative example.
It has a SPF of 2.2 times higher, and by coating finely divided zinc oxide on a cleaved swellable layered clay mineral and blending it, the dispersibility of zinc oxide is improved and a high UV protection effect is obtained. It was shown to be obtained. In particular Examples 5 and 7
Has a SPF value more than twice that of the comparative example,
The synergistic effect of the combined use of the surface-coated flaky powder according to the present invention and the ultraviolet absorber was shown. Further, Examples 4 to 8 of the present invention and Comparative Example 4
The feeling of use was evaluated using ~ 8. The evaluation items are three items of growth, blue glow, and white float, evaluated by 5 specialized panels, and Table 3 shows the number distribution of scores. [Table 3] From Table 3, it is clear that the example has better elongation than the comparative example and does not cause blue light or whitening. In addition, none of the users of each Example caused an allergic reaction or complained of irritation. As described above, according to the present invention, U
It was possible to obtain a highly functional powder capable of simultaneously protecting not only VB but also UVA region ultraviolet light. In addition, the cosmetic containing this powder has a high UV protection effect and good elongation, is excellent in safety, and has a natural cosmetic finish without bluish glow. Further, it was found that the combined use with an ultraviolet absorber synergistically improves the ultraviolet protection effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an ultraviolet shielding effect of the powder of Example 1.

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Claims (1)

Claims: 1. A surface-coated flaky powder obtained by coating the surface of a cleaved swelling layered clay mineral having a thickness of 0.001 to 0.2 μm and an aspect ratio of 30 to 100 with zinc oxide. body. 2. The surface-coated flaky powder according to claim 1, wherein the cleaved swellable layered clay mineral is one or more selected from smectites and vermiculites. 3. The surface coating according to claim 1, wherein the cleaved swelling layered clay mineral has a coverage with zinc oxide of 80% by weight or more based on the entire surface coated flaky powder. Flaky powder. 4. A surface-coated flaky powder obtained by further coating the surface of the surface-coated flaky powder according to claim 1 with a hydrophobic compound. 6. A method of coating a cleaved swelling clay mineral with a hydrolysis product of a zinc salt, and calcining at 300 to 700 ° C. to convert the hydrolysis product of the zinc salt to a zinc oxide.
The method for producing the surface-coated flaky powder according to claim 1. 7. A cosmetic comprising the surface-coated flaky powder according to any one of claims 1 to 4. 8. A sunscreen cosmetic comprising the surface-coated flaky powder according to any one of claims 1 to 4. 9. A powder cosmetic comprising the surface-coated flaky powder according to any one of claims 1 to 4. 10. The cosmetic according to claim 7, wherein the surface-coated flaky powder according to any one of claims 1 to 4 is used in combination with an ultraviolet absorber.