Oil-in-water sunscreen composition

Abstract

The present invention provides an oil-in-water type sunscreen composition that exhibits excellent soft-focus effect and emulsification stability, and contains an ultraviolet scattering agent. [Solution] An oil-in-water sunscreen composition containing components (A) to (D). Ingredient (A): 1.0-5.0% by weight of nonionic surfactant with an HLB of 11-15 Ingredient (B): Polyacrylamide compound 0.3-1.3% by weight Ingredients (C): Non-emulsified elastomer 0.6-1.3% by weight Ingredient (D): 5% or more by weight of particulate ultraviolet scattering agent

Description

Technical Field

[0001] The present invention relates to an oil-in-water type sunscreen composition that has an excellent soft focus effect and emulsion stability and contains an ultraviolet scattering agent.

Background Art

[0002] Protecting the skin from the harm of ultraviolet rays is one of the important issues of cosmetics. Various studies have been conducted to minimize the adverse effects of ultraviolet rays on the skin. For example, a method of protecting the skin from the harm of ultraviolet rays by covering the skin with a coating film containing an ultraviolet absorber or an ultraviolet scattering agent has been reported (Non-Patent Document 1).

[0003] In order to ensure the SPF (Sun Protection Factor) value in an oil-in-water type emulsion composition, it is necessary to blend a certain amount of an oil-soluble ultraviolet absorber or a powdery ultraviolet scattering agent. There is a problem with safety because skin irritation occurs when a high amount of the ultraviolet absorber is blended (Patent Document 1). On the other hand, the ultraviolet scattering agent is said to be safer than the ultraviolet absorber (Patent Document 2). Therefore, blending the ultraviolet scattering agent is effective for obtaining a highly safe composition. However, the ultraviolet scattering agent has often been a problem due to the deterioration of stability over time caused by the interaction between metal ions eluted from the metal oxide powder and surfactants, water-soluble polymers, etc.

[0004] As a method of giving the composition a skin correcting effect, it is common to use the hiding power of a coloring pigment. However, when the correcting power is increased, the finish becomes unnatural and the usability tends to deteriorate. In addition, it may not sufficiently exhibit an effect on correcting skin problems accompanied by unevenness on the skin surface. As a method of solving this, there is a method of blending a powder having optical properties and causing irregular reflection of light on the skin surface to make the unevenness less noticeable. This effect is generally called a soft focus effect.

[0005] Among powders having optical properties, non-emulsified elastomers have a high soft focus property. This is because they have a matrix with a three-dimensional crosslinked structure and the surface is covered with a spherical resin, so the light diffusion effect is high. However, non-emulsified elastomers are hydrophobic and have the property of being stable in the oil phase of an emulsion. Because the continuous phase of oil-in-water sunscreen compositions is water, the amount of oil that can be added tends to be small, making it difficult for non-emulsified elastomers to exist stably. Although there have been examples of small amounts being added to oil-in-water cosmetics (Patent Document 3), it has been difficult to stably incorporate an amount of non-emulsified elastomer that provides a sufficient soft-focus effect.

[0006] For these reasons, there has been a need for an oil-in-water sunscreen composition containing an ultraviolet scattering agent that exhibits excellent soft-focus effect and emulsification stability. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] "New Cosmetic Science," 2nd edition, edited by Takeo Mitsui, 2001, published by Nanzando, pp. 497-504. [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2003-206214 [Patent Document 2] Japanese Patent Publication No. 2015-124172 [Patent Document 3] Japanese Patent Publication No. 2020-94028 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] The present invention has been made in view of the above-mentioned prior art, and aims to provide an oil-in-water sunscreen composition containing an ultraviolet scattering agent that exhibits excellent soft-focus effect and emulsification stability. [Means for solving the problem]

[0010] As a result of diligent research by the inventors, it was discovered that the above problems could be solved by combining specific components, leading to the completion of the present invention.

[0011] In other words, the present invention is This is an oil-in-water type sunscreen composition containing the following components A to D. Ingredient (A): Nonionic surfactant with HLB of 11-15, 1.0-5.0% by weight Ingredient (B): Polyacrylamide compound 0.3-1.3% by weight Ingredients (C): Non-emulsified elastomer 0.6-1.3% by weight Ingredient (D): 5% or more by weight of particulate ultraviolet scattering agent [Effects of the Invention]

[0012] According to the present invention, it is possible to provide an oil-in-water type sunscreen composition containing an ultraviolet scattering agent that exhibits excellent soft-focus effect and emulsification stability. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 shows the evaluation criteria for soft focus. [Best Mode for Carrying Out the Invention]

[0014] The present invention will be described in more detail below. Unless otherwise noted, when the amount of ingredients is expressed in "%" below, it means by weight.

[0015] The nonionic surfactant (Component (A)) used in the present invention, having an HLB of 11 to 15, is not particularly limited as long as it is commonly used in cosmetics. Specifically, polyglycerol fatty acid esters, sucrose fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbit fatty acid esters, polyoxyethylene glycol fatty acid esters, polyoxyethylene glycerol fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene hydrogenated castor oil, fatty acid esters, polyoxyethylene fatty acid ethanolamides, polyoxyalkylene-modified silicones, polyoxyalkylene alkyl co-modified silicones, etc. can be mentioned.

[0016] Among them, it is preferable to use polyoxyethylene hydrogenated castor oil, polyglycerol fatty acid esters, and sorbitan fatty acid esters. Examples of commercially available products include Braunon RCW-50 and Braunon RGL-20MISE (manufactured by Aoki Yushi Kogyo).

[0017] The blending amount of the nonionic surfactant (Component (A)) having an HLB of 11 to 15 is not particularly limited as long as the effects of the present invention can be obtained, but it is used in the range of 1.0 to 5.0%, preferably 1. 0 to 3.0% based on the total amount of the composition. In this range, the emulsion stability is very excellent. Any one of these may be used alone, or two or more of them may be mixed and used.

[0018] As the component (B) polyacrylamide compound used in the present invention, there is no particular limitation, and those usually used in cosmetics can be used. Specifically, (sodium acrylate / sodium acryloyldimethyltaurine) copolymer, polyacrylamide, (dimethylacrylamide / sodium acryloyldimethyltaurine) cross-polymer, vinylpyrrolidone / 2-acrylamido-2-methylpropanesulfonic acid (salt) copolymer, sodium acrylate / 2-acrylamido-2-methylpropanesulfonic acid (salt) copolymer, acrylamide / sodium 2-acrylamido-2-methylpropanesulfonate copolymer, acrylamide / 2-acrylamido-2-methylpropanesulfonic acid (salt), homopolymer of sodium 2-acrylamido-2-methylpropanesulfonate, dimethylacrylamide / 2-acrylamido-2-methylpropanesulfonic acid, etc. can be mentioned.

[0019] Among them, from the viewpoints of good stability of the state over time and having a smooth and light feeling in use, the (sodium acrylate / sodium acryloyldimethyltaurine) copolymer can be preferably used. A commercially available product may be used as the (sodium acrylate / sodium acryloyldimethyltaurine) copolymer, for example, SIMULGEL EG (manufactured by SEPPIC) can be mentioned. Since the exemplified raw materials are composite raw materials, the range of the blending amount indicates the pure content of the polyacrylamide compound.

[0020] The blending amount of the component (B) polyacrylamide compound is not particularly limited as long as the effects of the present invention can be obtained, but preferably it is in the range of 0.3 to 1.3%, more preferably 0.4 to 0.8% in terms of pure content based on the total amount of the composition. In this range, the emulsion stability is very excellent. These may be used alone or in appropriate combination of two or more kinds.

[0021] The component (C) non-emulsified elastomer used in the present invention is not particularly limited, and any elastomer commonly used in cosmetics can be used. Preferred components include partially crosslinked organopolysiloxane polymers. Preferred partially crosslinked organopolysiloxane polymers include crosspolymers obtained by the reaction of methylhydrogenpolysiloxane and phenylvinyl dimethicone (hereinafter referred to as "dimethicone / phenylvinyl dimethicone) crosspolymer", crosspolymers obtained by the reaction of methylhydrogenpolysiloxane and methylvinylpolysiloxane (hereinafter referred to as "dimethicone / vinyl dimethicone crosspolymer"), crosspolymers obtained by the reaction of partially long-chain alkylated methylhydrogenpolysiloxane and methylvinylpolysiloxane (hereinafter referred to as "vinyl dimethicone / alkyl dimethicone crosspolymer"), and crosspolymers obtained by the reaction of methylhydrogenpolysiloxane and alkenes (hereinafter referred to as "dimethicone crosspolymer").

[0022] In particular, dimethicone / vinyl dimethicone crosspolymer can be preferably used from the viewpoint of having good stability over time and a smooth feel. A commercially available mixed dimethicone / vinyl dimethicone crosspolymer may also be used, for example, KSG-16 (manufactured by Shin-Etsu Chemical Co., Ltd.). Since the exemplified raw materials are composite raw materials, the range of blending amounts indicates the purity of the non-emulsified elastomer. In vinyl dimethicone / alkyl dimethicone crosspolymers, the partially long-chain alkylated methylhydrogenpolysiloxane preferably has 10 to 18 carbon atoms in the long-chain alkyl group.

[0023] The amount of component (C) non-emulsified elastomer is not particularly limited as long as the effects of the present invention are obtained, but it is preferably used in an amount of 0.6 to 1.3, more preferably 0.8 to 1.0, relative to the total amount of the composition in terms of pure content. In this range, the coatability and soft-focus properties are excellent. These may be used individually or in appropriate combinations of two or more types.

[0024] The component (D) fine particle ultraviolet scattering agent used in the present invention is a fine powder of a metal oxide, such as titanium dioxide or zinc oxide. Fine powder refers to powder with an average particle size of about 10 to 200 nm. The fine powder of the metal oxide may be a fine powder that has been surface-treated with a stabilizer such as isostearic acid, dimethicone, or hydrogen dimethicone. Such surface treatment can suppress the activity of the metal oxide and provide effects such as suppressing the deterioration of cosmetics.

[0025] The particle size or average particle size of the powder particles shall be the value provided by the raw material manufacturer. If no value is provided, it may be calculated by measuring with a laser diffraction / scattering particle size distribution analyzer (e.g., LA-920, manufactured by Horiba, Ltd.) using ethanol as the dispersion medium. In this case, the average particle size refers to the 50% diameter obtained from the volume distribution of the particle size distribution.

[0026] The amount of component (D) fine particle ultraviolet scattering agent is not particularly limited as long as the effects of the present invention can be obtained, but it is preferably used in the range of 5 to 28%, more preferably 5 to 20%, of the total amount of the composition. In this range, the emulsification stability is excellent. These fine particle ultraviolet scattering agents may be used individually or in appropriate combinations of two or more types.

[0027] In this application, the aqueous component refers to water and components that are compatible with water. Specifically, it refers to water and components whose solubility in water at 25°C is 1% by mass or more, in other words, components with a solubility of 10 g / L or more. For example, it refers to surfactants and polyhydric alcohols, and does not include powders.

[0028] In addition to the essential components mentioned above, the composition of the present invention may also contain other components commonly used in cosmetics, as needed. For example, pearlescent agents, moisturizers, thickeners, water-soluble polymers other than component (B) polyacrylamide compounds, fragrances, bactericides, preservatives, antioxidants, pH adjusters, chelating agents, anti-inflammatory agents, antioxidants, cooling agents, herbal extracts, and vitamins may be added as appropriate. The proportion of these components can be appropriately selected depending on their type and purpose, and they may be used individually or in combination of two or more as appropriate. [Examples]

[0029] The present invention will be further explained below with reference to examples. These examples are not intended to limit the present invention in any way.

[0030] <Manufacturing method> According to the formulations shown in Tables 1 and 2 below, component (D) fine-particle ultraviolet scattering agent, polyhydroxystearic acid, and isotridecyl isononanoate were kneaded using a three-roller system. Component (C): non-emulsified elastomer and other oily components were added and further mixed and uniformly dispersed. This was the oil phase. Subsequently, component (A) a nonionic surfactant with an HLB of 11 to 15, (B) a polyacrylamide compound, and other aqueous components were mixed and uniformly dispersed. This was the aqueous phase. The oil phase was added to the aqueous phase by stirring and emulsified. The oil-in-water sunscreen compositions of the examples and comparative examples were obtained by the above method.

[0031] <Stability over time> The prepared formulation is left to stand at 60°C for two weeks, and its condition (change in appearance, separation) is visually checked after two weeks. ◎: No state changes such as separation have occurred. ○: Slight changes in state, such as separation, have occurred, but these do not affect the product quality during use. △: Some changes in state, such as separation, have occurred, which is undesirable from a product quality standpoint. ×: This indicates a significant change in state, such as separation, which is undesirable from a product quality standpoint.

[0032] <Sensory Characteristics Evaluation Test: Soft Focus Effect> In the sensory characteristics evaluation test, 10 expert evaluators assessed the soft-focus effect when the evaluation samples were applied to the face. They assigned higher scores to each sample (example and comparative example) according to the following evaluation criteria, with higher scores indicating a greater perceived soft-focus effect. A score of 4.0 or higher was marked with ◎, 3.0 to less than 4.0 with ○, 2.0 to less than 3.0 with △, and less than 2.0 with ×. Furthermore, Figure 1 shows how samples with values ​​of 4.0 or higher, 3.0 or higher but less than 4.0, 2.0 or higher but less than 3.0, and less than 2.0 appear when coated onto a quartz plate and placed on top of letters.

[0033] The formulations and evaluation results are shown in Tables 1 and 2. The following commercially available products were used for the raw materials listed in the tables. Sodium acrylate / sodium acryloyldimethyl taurate copolymer (37.5% purity): SIMULGEL EG (manufactured by SEPPIC) • Polyacrylamide (37.5% purity): SEPIGEL 305 (manufactured by SEPPIC) • Cross-linked methylpolysiloxane (25% purity): Silicon KSG-16 (manufactured by Shin-Etsu Chemical Co., Ltd.) • Dimethicone crosspolymer (12.6% purity): 9045 SILICONEELASTOMERBLEN (manufactured by Toray Dow Corning Silicone Co., Ltd.) • (Dimethicone / Phenylenin Dimethicone) Crosspolymer (25% purity): Silicone KSG-18A (manufactured by Shin-Etsu Chemical Co., Ltd.) • Acrylic acid / alkyl methacrylate copolymer: PEMULEN TR-2 (manufactured by LUBRIZOL) • Low-temperature calcined zinc oxide (97% purity): MZX-300M (manufactured by Teika Co., Ltd.) • Fine particle titanium dioxide (84% purity): STR-100A-LP (manufactured by Sakai Chemical Industry Co., Ltd.)

[0034] [Table 1]

[0035] [Table 2]

[0036] As can be seen from Table 1, Examples 1 to 13 of the present invention showed good results in terms of both storage stability and soft-focus effect. An oil-in-water sunscreen composition was obtained that exhibits excellent soft-focus effect and emulsification stability, and contains an ultraviolet scattering agent.

[0037] Referring to Examples 1 to 13 in Table 1 and Comparative Examples 1 to 12 in Table 2, In Examples 1, 2, and 3, different types of nonionic surfactants with HLB values ​​of 11 to 15 were used, and all showed good temporal stability and soft-focus effect. In particular, a tendency for good temporal stability was observed with surfactants with high HLB values ​​of 14 and 15. In Example 6, good temporal stability and soft-focus effect were observed even when different types of (B) polyacrylamide compounds were used. However, in Example 7, reducing the amount tended to decrease emulsification stability, and approximately 0.8% was considered the lower limit. Comparative Example 1, which used an anionic surfactant, had good usability, but its temporal stability deteriorated. Comparative Examples 3 and 4 incorporated polymers other than (B) polyacrylamide compound, but heterogeneity was observed immediately after emulsification, and stability tended to deteriorate significantly. In Comparative Example 4, when (B) polyacrylamide compound was omitted, heterogeneity was observed immediately after emulsification. Furthermore, in Comparative Example 5, even with 0.5% (0.185% purity) of (B) polyacrylamide composite raw material, temporal stability was poor. Aggregation of the UV scattering agent was also observed due to the heterogeneity, and usability deteriorated. The type and amount of polymer strongly influenced the stability of the system. (C) When the non-emulsified elastomer was omitted, there were no problems with stability over time, but the soft-focus effect could not be sufficiently obtained. Comparative Examples 9 and 11 are formulations of Example 1 to which an effective amount of the ultraviolet absorber described in prior patent application JP 2020-94028 has been added. Non-uniformity was observed immediately after emulsification. It is possible that reducing the amount of water to incorporate the ultraviolet absorber negatively affected the stability of the oil-in-water emulsion. However, Example 12, a formulation with a large amount of ultraviolet scattering agent and consequently less water, showed good stability over time. Even in Comparative Example 10, where the amount of ultraviolet scattering agent was reduced to about 5%, the stability over time was better than that of Comparative Example 9, but worse than that of Example 12. In the present invention, the combined use of an ultraviolet absorber is undesirable in terms of stability.

[0038] The compositions for each formulation were prepared using conventional methods. It was confirmed that all formulations exhibited the effects of the present invention.

[0039] (1) Oil-in-water sunscreen composition Ingredients Amount (%) 1. Low-temperature calcined zinc oxide 7.8 2. Fine particle titanium dioxide 5.0 3. Light liquid isoparaffin 5.0 4. Isotridecyl isononanoate 5.0 5.1,3-Butylene glycol 5.0 6. Methylpolysiloxane 2.5 7. Sodium acrylate / sodium acryloyldimethyl taurate copolymer / isohexadecane / polysorbate 80 1.0 8. Polyoxyethylene hydrogenated castor oil 1.0 9. Cross-linked methylpolysiloxane 0.75 10. Polyhydroxystearic acid 1.0 11. Hydrated silica 0.5 12. Aluminum hydroxide 0.25 13. Low viscosity methylhydrogenpolysiloxane 0.25 14. pH adjuster (appropriate amount) 15.Preservatives Appropriate amount 16.Water Residual Total 100 Total of 72 water-based components only

[0040] (2) Oil-in-water makeup base Ingredients Amount (%) 1. Low-temperature calcined zinc oxide 9.8 2,1,3-Butylene glycol 6.0 3. Concentrated glycerin 4.8 4. Isotridecyl isononanoate 4.2 5. Light liquid isoparaffin 4.0 6. Methylpolysiloxane 2.8 7. Titanium dioxide 2.8 8. Fine particle titanium dioxide 2.3 9. Glycosyltrehalose / hydrogenated starch hydrolysate mixed solution 2.0 10. Dipropylene glycol 2.0 11. Polyoxyethylene hydrogenated castor oil 1.2 12. Sodium acrylate / sodium acryloyldimethyl taurate copolymer / isohexadecane / polysorbate 80 1.0 13. N-Lauroyl-L-Glutamate Di(Phytosteryl·2-Octyldodecyl) 1.0 14. Potassium cetyl phosphate 0.9 15. Sorbitan sesquiisostearate 0.8 16. Polyhydroxystearic acid 0.8 17. Cross-linked methylpolysiloxane 0.75 18. Dimer dilinoleyl dimer dilinoleate 0.5 19. Pentaerythritol tetra-2-ethylhexanoate 0.28 20. Perfluoroalkyldimethyltrimethylsiloxysilicate 0.25 21. Hydrated silica 0.22 22. Polyoxyethylene glyceryl isostearate 0.2 23. Aluminum hydroxide 0.2 24. Yellow iron oxide 0.17 25. Glycerin mono-2-ethylhexyl ether 0.15 26. Phenoxyethanol 0.15 27. Low viscosity methylhydrogenpolysiloxane 0.1 28. Polyoxyethylene cetyl ether 0.1 29. Xanthan gum 0.1 30. Methylhydrogenpolysiloxane 0.06 31. Stearyl glycyrrhetinate 0.05 32. d-δ-tocopherol 0.05 33. Polyethylene glycol, decyltetradeceth-20, hexamethylene diisocyanate copolymer 0.05 34. Hydrophobized hydroxypropyl methylcellulose 0.05 35. Bengara (red iron oxide pigment) 0.04 36. pH adjuster (appropriate amount) 37.Preservatives Appropriate amount 38.Water Residual Total 100 Total of water-based components: 68.8

Claims

1. An oil-in-water sunscreen composition containing components (A) to (D). Ingredient (A): 1.0 to 5.0% by weight of a nonionic surfactant with an HLB of 11 to 15 Component (B): Polyacrylamide compound 0.3 to 1.3% by weight Ingredient (C): Non-emulsified elastomer 0.6 to 1.3% by weight Ingredient (D): 5% or more by weight of particulate ultraviolet scattering agent

2. The oil-in-water sunscreen composition according to claim 1, wherein the component (B): polyacrylamide compound is one or two selected from (sodium acrylate / sodium acryloyldimethyl taurate) copolymer or polyacrylamide.

3. The oil-in-water sunscreen composition according to claim 1 or claim 2, wherein the aforementioned component (D): particulate ultraviolet scattering agent is present in an amount of 5 to 28% by weight.

4. The oil-in-water sunscreen composition according to claim 1 or claim 2, wherein the ratio of aqueous components is 45% by weight or more.

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