Oil-in-water emulsified sunscreen cosmetics

Abstract

The object of the present invention is to provide an oil-in-water emulsified sunscreen cosmetic that can achieve high ultraviolet protection by improving the ultraviolet protection of an ultraviolet scattering agent and has excellent emulsification stability. The sunscreen cosmetic of the present invention is characterized in that it contains: (A) an acrylic copolymer having a phosphate group, (B) a hydrophobized ultraviolet scattering agent, and (C) 0.3% by mass or more of an aqueous phase thickener, wherein the ultraviolet scattering agent is dispersed in an oil layer.

Description

Technical Field

[0001] The present invention relates to an oil-in-water emulsified sunscreen cosmetic, and more specifically to an oil-in-water emulsified sunscreen cosmetic that can achieve high ultraviolet protection by combining a specific polymer compound with an ultraviolet scattering agent. Background Art

[0002] Oil-in-water cosmetics are widely used as bases for skin external preparations such as skin cosmetics that are directly applied to the skin because they provide a refreshing and delicate touch when applied to the skin. Among them, skin care and body care are performed daily to protect the skin from ultraviolet rays. Among such sunscreen cosmetics, the importance of sunscreen cosmetics based on oil-in-water cosmetics is increasing.

[0003] As the UV protection agent for sunscreen cosmetics, there are usually UV absorbers and UV scatterers. UV absorbers are also solid at room temperature, and a corresponding amount of oil is required in order to stably dissolve in cosmetics without precipitation. Therefore, if you want to increase the amount of UV absorbers to obtain a high UV protection effect, you have to increase the amount of oil, which will cause a sticky feeling due to the oil, which may damage the feeling of use. In addition, if you want to increase the amount of UV scatterers to obtain a high UV protection effect, there is a situation where the fluidity in the coating film is reduced and the roughness (the touch of lack of smoothness) is felt over time.

[0004] Therefore, a technology for obtaining a high UV protection effect with a smaller amount of UV protection agent has been proposed. For example, the applicant described in Patent Document 1 that the UV protection effect can be improved by adding porous spherical powders such as silica to water-based or oil-in-water sunscreen cosmetics containing UV absorbers.

[0005] A system that can achieve high UV protection effects with a smaller amount of UV scattering agents is also sought. In addition, it is difficult to stably mix UV protection agents in the oil layer that serves as the inner layer of oil-in-water type sunscreen cosmetics.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-090468 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] An object of the present invention is to provide an oil-in-water emulsified sunscreen cosmetic which can achieve high ultraviolet protection by improving the ultraviolet protection of an ultraviolet scattering agent and has excellent emulsion stability.

[0011] Solutions for solving problems

[0012] The inventors have conducted intensive studies to solve the above problems and have found that the UV protection of the UV scattering agent is improved when a combination of an acrylic copolymer having a phosphate group, a hydrophobized UV scattering agent and an aqueous thickener is added. This has led to the completion of the present invention.

[0013] That is, the present invention provides:

[0014] An oil-in-water emulsified sunscreen cosmetic comprising:

[0015] (A) an acrylic copolymer having a phosphoric acid group,

[0016] (B) a hydrophobic treatment ultraviolet scattering agent, and

[0017] (C) 0.3% by mass or more of a water-phase thickener,

[0018] The aforementioned ultraviolet scattering agent is dispersed in the oil layer.

[0019] Effects of the Invention

[0020] The cosmetics of the present invention, by having the above-mentioned technical features, can realize an oil-in-water emulsified sunscreen cosmetic that can improve the UV protection of the UV scattering agent added to the sunscreen cosmetic and has excellent emulsification stability. In addition, since the emulsification stability of the emulsified cosmetics of the present invention is sufficiently maintained, a UV absorber as a highly polar oil can be further added. DETAILED DESCRIPTION

[0021] The sunscreen cosmetic of the present invention is characterized by comprising (A) an acrylic copolymer having a phosphoric acid group, (B) a hydrophobized ultraviolet scattering agent, and (C) an aqueous phase thickener. The components constituting the cosmetic of the present invention are described in detail below.

[0022] <(A) Acrylic Copolymer Having Phosphoric Acid Group>

[0023] (A) The acrylic copolymer having a phosphoric acid group (hereinafter sometimes simply referred to as "component (A)") contained in the sunscreen cosmetic of the present invention refers to a copolymer containing an acrylic monomer and an acrylic monomer having a phosphoric acid group.

[0024] Acrylic monomers refer to monomers containing acrylic acid, methacrylic acid or their alkyl esters. The alkyl group bonded by the ester bond may be any of a linear or branched type, and the number of carbon atoms thereof is 1 to 30, preferably 1 to 20. Examples, without limitation, include monomers such as (meth)acrylic acid, methyl (meth)acrylate, (meth)acryloyloxyethyl, and 2-ethylhexyl (meth)acrylate.

[0025] The acrylic monomer having a phosphoric acid group is an acrylic monomer in which the carboxyl group of acrylic acid or methacrylic acid is esterified by an alkyl group and has a phosphoric acid group in the alkyl group. Specific examples thereof include, but are not limited to, phosphoryloxyethyl acrylate, phosphoryloxyethyl methacrylate, and phosphoryloxymethyl acrylate.

[0026] Although not limited as a specific example of the acrylic copolymer having a phosphoric acid group, an acrylic acid (ester) type / methacryloyloxyethyl phosphate copolymer can be mentioned.

[0027] The acrylic copolymer of the present invention can be provided in the form of an aqueous dispersion in which acrylic polymer particles are dispersed in an aqueous solvent. As a commercially available product, SOLTEX TM INO polymer (aqueous dispersion with a solid content of 31%, manufactured by Dow Chemical Japan Limited) and the like.

[0028] The amount of the acrylic copolymer having a phosphoric acid group (A) is preferably 0.1 to 10% by mass, more preferably 0.2 to 8% by mass, and even more preferably 0.5 to 5% by mass, relative to the total amount of the sunscreen cosmetic. If the amount of component (A) is less than 0.1% by mass, the effect of improving the ultraviolet protection is insufficient, while if it exceeds 10% by mass, the emulsion stability tends to deteriorate.

[0029] <(B) Hydrophobic treatment UV scattering agent>

[0030] The (B) hydrophobized ultraviolet scattering agent (hereinafter sometimes simply referred to as "component (B)") formulated in the sunscreen cosmetic of the present invention is a powder that physically blocks ultraviolet rays by reflection or scattering, and is a powder having a hydrophobized surface.

[0031] The ultraviolet scattering agent of the present invention is not particularly limited, and examples thereof include fine particle metal oxides such as zinc oxide, titanium oxide, iron oxide, cerium oxide, tungsten oxide, etc. In the present invention, zinc oxide or titanium oxide is preferably used.

[0032] The average primary particle size of the ultraviolet scattering agent of the present invention is not particularly limited, and is 10 nm to 100 nm, preferably 10 nm to 50 nm. Here, the average primary particle size in this specification refers to the diameter of the primary particles of the powder measured by a commonly used method, specifically, the value obtained by the arithmetic average of the length of the major axis and the length of the minor axis of the particles from a transmission electron microscope photograph.

[0033] The shape of the ultraviolet scattering agent of the present invention is not particularly limited, and may be spherical, elliptical, or crushed.

[0034] As the hydrophobic treatment agent of the ultraviolet scattering agent of the present invention, various compounds that can be used in the hydrophobic surface treatment of the ultraviolet scattering agent used in cosmetics, etc., such as fatty acids, siloxane compounds, fluorine compounds, silane coupling agents, oils, quaternary ammonium salt compounds, etc. can be listed. However, if fatty acid esters are used for hydrophobic treatment, the desired ultraviolet defense improvement effect may not be obtained. Therefore, the (B) hydrophobic treatment ultraviolet scattering agent in the present invention refers to "ultraviolet scattering agent that has been hydrophobicized using something other than fatty acid esters".

[0035] The fatty acid to be treated is not limited, and examples thereof include palmitic acid, isostearic acid, stearic acid, lauric acid, myristic acid, behenic acid, oleic acid, abietic acid, and 12-hydroxystearic acid.

[0036] The siloxane compound is not limited, and examples thereof include silicone oils such as methyl hydrogen polysiloxane (hydrogen polydimethylsiloxane), dimethyl polysiloxane (polydimethylsiloxane), and methylphenyl polysiloxane.

[0037] The fluorine compound is not limited, and examples thereof include esters containing a perfluoroalkyl group, perfluoropolyethers, and polymers having a perfluoroalkyl group.

[0038] The silane coupling agent is not limited, and examples thereof include fluoroalkylsilane compounds such as perfluoroalkylsilane, trifluoromethylethyltrimethoxysilane, and heptadecafluorodecyltrimethoxysilane; and alkylsilane compounds such as methyltriethoxysilane, ethyltriethoxysilane, hexyltriethoxysilane, and octyltriethoxysilane.

[0039] The oil agent is not limited, and examples thereof include liquid paraffin, squalane, vaseline, lanolin, microcrystalline wax, polyethylene wax, and the like.

[0040] The quaternary ammonium salt compound is not limited, and examples thereof include stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, cetyltrimethylammonium chloride, distearyldimethylammonium chloride, dibehenyldimethylammonium chloride, dicetyldimethylammonium chloride, stearyldimethylbenzylammonium chloride, and dilauryldimethylammonium chloride.

[0041] These hydrophobic treatments can be performed according to conventional methods, and the hydrophobic surface treatment agents may be used alone or in combination of two or more.

[0042] As the hydrophobic treatment of the ultraviolet scattering agent in the present invention, a hydrophobic treatment using a silicone compound or a quaternary ammonium salt compound is preferred.

[0043] The ultraviolet scattering agent of the present invention may be an ultraviolet scattering agent covered with silica or alumina, and the ultraviolet scattering agent covered with silica or alumina may be surface-treated with the hydrophobicizing agent before use.

[0044] Commercially available products used as the hydrophobized ultraviolet scattering agent of the present invention are not limited, and examples thereof include OTQ-MT-100Si (distearyldimethylammonium chloride-treated silica fine particle titanium oxide, manufactured by TAYCA CORPORATION), STR-100C-LP (hydrogenated polydimethylsiloxane / aluminum hydroxide-treated titanium oxide, manufactured by Sakai Chemical Industry Co., Ltd.), and FINEX-50W-LP2 (hydrogenated polydimethylsiloxane / silica-treated zinc oxide, manufactured by Sakai Chemical Industry Co., Ltd.).

[0045] The amount of the (B) hydrophobized ultraviolet scattering agent to be added is not particularly limited, but is usually 1% by mass or more, for example, 1 to 40% by mass, preferably 1 to 30% by mass, relative to the total amount of the cosmetic. If the (B) hydrophobized ultraviolet scattering agent is added in an amount of less than 1% by mass, it is difficult to obtain a sufficient ultraviolet protection effect, and even if it is added in an amount exceeding 40% by mass, an increase in ultraviolet protection effect corresponding to the amount added cannot be expected, which is not preferred from the viewpoint of poor stability, etc.

[0046] <(C) Water phase thickener>

[0047] The (C) aqueous phase thickener (hereinafter sometimes simply referred to as "component (C)") formulated in the sunscreen cosmetic of the present invention may be an aqueous phase thickener generally formulated in cosmetics to improve the thickening property of the aqueous phase. Specifically, there are no limitations, and various hydrophilic thickeners such as natural water-soluble polymers, semi-synthetic water-soluble polymers, synthetic water-soluble polymers, and inorganic thickeners may be cited.

[0048] As natural water-soluble polymers, there can be listed, for example, plant polymers such as gum arabic, tragacanth gum, galactan, guar gum, carrageenan, pectin, quince seed (marmelo) extract, agar, brown algae powder, etc.; microbial polymers such as xanthan gum, dextran, pullulan, succinoglycan, etc.; animal polymers such as collagen, casein, albumin, gelatin, etc., etc.

[0049] As the semi-synthetic water-soluble polymer, there can be listed, for example, starch-based polymers such as carboxymethyl starch and methyl hydroxy starch; cellulose-based polymers such as methyl cellulose, nitrocellulose, ethyl cellulose, methyl hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose stearyl ether, cellulose sulfate, hydroxypropyl cellulose, carboxymethyl cellulose, and crystalline cellulose; and alginic acid-based polymers such as sodium alginate and propylene glycol alginate.

[0050] Examples of synthetic water-soluble polymers include vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl methyl ether, polyvinyl pyrrolidone, copolymers of vinyl pyrrolidone and vinyl acetate, and carboxyvinyl polymers; acrylic polymers such as sodium polyacrylate, polyethyl acrylate, polyacrylamide, acrylic acid / alkyl methacrylate copolymers (e.g., acrylic acid (ester) / C10-30 alkyl acrylate crosslinked polymers), polyacrylic acid alkanolamine, alkyl methacrylate and dimethylaminoethyl methacrylate copolymers, poly-2-acrylamide-2-methylpropanesulfonic acid, polymethacryloyloxytrimethylammonium, ammonium acryloyldimethyltaurate / VP copolymers, and dimethylacrylamide / sodium acryloyldimethyltaurate copolymers.

[0051] Examples of the inorganic thickener include bentonite, Laponite, hectorite, magnesium aluminum silicate, and silicic anhydride.

[0052] (C) As the aqueous phase thickener, one kind or a combination of two or more kinds can be used.

[0053] In the sunscreen cosmetic of the present invention, there is a tendency for a sticky feeling to occur when a thickener derived from sugar is used. Therefore, it is preferred to use an aqueous phase thickener other than a thickener derived from sugar.

[0054] Among them, in the cosmetic of the present invention, it is preferred to use at least one selected from acrylic acid / alkyl methacrylate copolymers, carboxyvinyl polymers, agar, hydroxypropyl methylcellulose stearyl ether, dimethylacrylamide / sodium acryloyldimethyltaurate copolymers, and succinoglycan.

[0055] (C) The amount of the aqueous phase thickener is 0.3% by mass or more relative to the total amount of the cosmetic. The upper limit of the amount may be the usual upper limit of the amount of the cosmetic, for example, preferably 2% by mass or less. If the amount is less than 0.3% by mass, the emulsion stability deteriorates.

[0056] In the sunscreen cosmetic of the present invention, if two or more selected from the above-mentioned aqueous phase thickeners are used in combination as the component (C), a cosmetic having a further improved feel during use can be obtained. For example, the component (C) of the present invention is preferably a mixture of two or more selected from acrylic acid / alkyl methacrylate copolymers, carboxyvinyl polymers, agar, xanthan gum, hydroxypropyl methylcellulose stearyl ether, dimethylacrylamide / sodium acryloyldimethyltaurate copolymers, and succinoglycans.

[0057] In addition, in the sunscreen cosmetics of the present invention, a thickener derived from sugar can also be used. In order to improve the feel during use, when a thickener derived from sugar (e.g., xanthan gum, agar, succinoglycan, hydroxypropylmethylcellulose stearyloxy ether) is used, it is preferably combined with a low salt-tolerant aqueous phase thickener. A low salt-tolerant aqueous phase thickener refers to a thickener that produces a decrease in viscosity due to the presence of electrolytes in a concentration range that is usually formulated in cosmetics, and is also referred to as a thickener that produces a decrease in viscosity due to an increase in electrolyte concentration.

[0058] The thickener that decreases the viscosity due to an increase in the electrolyte concentration is not particularly limited, and examples thereof include vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl methyl ether, polyvinyl pyrrolidone, vinyl pyrrolidone and vinyl acetate copolymers, and carboxyvinyl polymers; acrylic polymers such as sodium polyacrylate, polyethyl acrylate, polyacrylic acid alkanolamine, alkyl methacrylate and dimethylaminoethyl methacrylate copolymers, poly 2-acrylamide-2-methylpropanesulfonic acid, polymethacryloyloxytrimethylammonium, ammonium acryloyldimethyltaurate / VP copolymers, and dimethylacrylamide / sodium acryloyldimethyltaurate copolymers; and the like.

[0059] The sunscreen cosmetic of the present invention is manufactured as an oil-in-water emulsion in which an ultraviolet scattering agent is dispersed in an oil phase as an inner layer, and thus the ultraviolet protection capability of the ultraviolet scattering agent can be improved.

[0060] In the sunscreen cosmetic of the present invention, the blending mass ratio of (A) the acrylic copolymer having a phosphate group to (C) the aqueous phase thickener is preferably 1:7 to 8:1 from the viewpoint of obtaining a cosmetic having excellent emulsion stability.

[0061] Since the sunscreen cosmetic of the present invention is excellent in emulsification stability, it may further contain (D) an ultraviolet absorber (hereinafter sometimes simply referred to as "component (D)") which is a highly polar oil.

[0062] The ultraviolet absorber used in the present invention is not particularly limited, and specific examples thereof include organic ultraviolet absorbers such as ethylhexyl methoxycinnamate, octocrylene, dimethicone diethylbenzylidene malonate, polysilicone-15, tert-butyl methoxydibenzoylmethane, ethylhexyl triazone, diethylaminohydroxybenzoyl hexyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, benzophenone-3, methylene bisbenzotriazolyl tetramethylbutylphenol, phenylbenzimidazole sulfonic acid, homosalate, and ethylhexyl salicylate. The ultraviolet absorber used in the present invention may be blended alone or in combination of two or more.

[0063] When the (D) ultraviolet absorber is blended, the amount is preferably 1 to 40% by mass, more preferably 1 to 30% by mass, based on the total amount of the cosmetic.

[0064] The sunscreen cosmetic of the present invention further improves the rate of improvement in ultraviolet protection when (E) a porous spherical powder having an average particle size of 1 to 4 μm and an oil absorption of 160 ml / 100 g or less (hereinafter sometimes simply referred to as "component (E)") is added.

[0065] The average particle size of the porous spherical powder as the component (E) of the present invention is 1 to 4 μm, more preferably 1.5 to 4 μm. When the average particle size is less than 1 μm, there is a tendency for the handling to deteriorate. If it exceeds 4 μm, in addition to not being able to obtain a high UV protection improvement effect, there is also a tendency for a granular feel to deteriorate the usability. It should be noted that the average particle size in the present invention is the value obtained by adding 0.05 g of the powder to 20 g of an ethanol solvent, using an ultrasonic homogenizer (US-150T; manufactured by Nippon Seiki Seisaku-sho) for 1 minute of ultrasonic dispersion, and using a laser diffraction / scattering particle size distribution measuring device (MT3300EXII; manufactured by MicrotracBEL Corp) as the volume average particle size (D50).

[0066] The oil absorption of the porous spherical powder (E) is 160 ml / 100 g or less, more preferably 50 to 160 ml / 100 g, and even more preferably 60 to 160 ml / 100 g, as measured according to JIS K5101-13-2 (boiled linseed oil method). If the oil absorption is within the above range, the UV protection effect can be sufficiently improved.

[0067] The shape of the porous spherical powder (E) is spherical, particularly preferably true spherical. The closer the shape of the component (E) is to a true spherical shape, the more uniform the thickness of the cosmetic film can be formed on the skin, thereby achieving a high UV protection improvement effect. In the present invention, a true spherical shape means that the particle size is generally true circular when projected from any direction, and the minimum particle size is 80% or more of the maximum value, more preferably 90% or more.

[0068] The material constituting the (E) porous spherical powder is not particularly limited, and examples thereof include silicon dioxide (silicic anhydride) and cellulose, and among these, silicon dioxide is preferred.

[0069] Commercially available products of silica powder that can be used as the (E) porous spherical powder include, for example, GoddBall E-6C and GoddBall B-6C (both manufactured by Suzuki Oil & Fats Industries, Ltd.), SILICA MICRO BEAD P-500 (manufactured by JGC Catalysts & Chemicals, Ltd.), and SUNSPHERE L-31 (manufactured by AGC Si-Tech Co., Ltd.).

[0070] The porous spherical powder (E) can be used alone or in combination of two or more. The amount of the component (E) is preferably 1 to 5% by mass, more preferably 2 to 4% by mass, relative to the total amount of the sunscreen cosmetic. When the amount of the component (E) is less than 1% by mass, there is a tendency that the effect of improving the ultraviolet protection achieved by the component (E) cannot be fully exerted, and when it exceeds 5% by mass, the usability may be deteriorated.

[0071] <Optional ingredients>

[0072] In addition to the above ingredients, the sunscreen cosmetics of the present invention may contain ingredients commonly used in cosmetics within the range that does not hinder the effects of the present invention. For example, oil, water, alcohols, moisturizers, oil phase thickeners, surfactants, film coating agents, powder ingredients, drug ingredients, stabilizers, chelating agents, preservatives, fragrances, etc. may be appropriately contained as needed.

[0073] The sunscreen cosmetics of the present invention can be produced by conventional methods. For example, a mixed solution of oil phase components that are heated and mixed separately is added to a mixed solution obtained by heating and mixing water phase components, and an aqueous dispersion of an acrylic copolymer having a phosphoric acid group is added to the obtained mixed solution, followed by sufficient stirring, thereby producing an oil-in-water emulsion cosmetic.

[0074] The sunscreen cosmetics of the present invention can be manufactured as a lotion imparting a sunscreen effect, in addition to sunscreen creams, sunscreen lotions, and sunscreen skin lotions.

[0075] The present invention is based on the following discovery: by combining an acrylic copolymer having the function of preventing the aggregation of ultraviolet scattering agents in a cosmetic coating on the skin with a specific amount of an aqueous thickener to form an oil-in-water type emulsion, the ultraviolet protection of the ultraviolet scattering agent can be particularly significantly improved. The mechanism of the ultraviolet protection improvement of the present invention is different from the conventional mechanism of improving ultraviolet protection based on making the cosmetic coating uniform, and even if combined with porous spherical powders having the conventional mechanism, the mechanisms do not antagonize each other, and an additive or synergistic ultraviolet protection improvement effect can be obtained.

[0076] The sunscreen cosmetic of the present invention can sufficiently improve the UV protection even without adding a hollow polymer (e.g., a hollow polymer of a styrene / acrylic acid (ester) copolymer) that has been reported to have an effect of improving UV protection. Therefore, the present invention includes an embodiment that does not contain a hollow polymer.

[0077] Example

[0078] The present invention is described in more detail by way of examples below, but the present invention is not limited thereto. The amount of the compounding is expressed as mass % relative to the system of the compounding component unless otherwise specified. Before describing each example in detail, the evaluation method used is described.

[0079] <Improvement rate of UV protection>

[0080] The measurement plate (S plate) (5×5 cm V-groove PMMA plate, SPFMASTER-PA01) was quenched at 2 mg / cm 2 The cosmetics (samples) of each example were added dropwise, applied with a finger for 60 seconds, and dried for 15 minutes. The absorbance of the formed coating was measured using a U-3500 self-recording spectrophotometer manufactured by Hitachi, Ltd. The uncoated plate was used as a control, and the absorbance (Abs) was calculated using the following formula. The measured values ​​at 280nm to 400nm were integrated to obtain the integrated absorbance value.

[0081] Abs=-log(T / To)

[0082] T: transmittance of the sample, To: transmittance without coating

[0083] The improvement rate of ultraviolet protection based on the control sample was calculated from the obtained sample absorbance cumulative value using the following formula. It should be noted that for Test Examples 1 to 7, for each Test Example, the sample without the (A) component was used as the control sample. For Test Examples 10 to 12, the sample without the (A) component of the present invention and silica was used as the control sample.

[0084] [Improvement rate of ultraviolet protection (%)] = [Cumulative absorbance value of sample] / [Cumulative absorbance value of control sample] × 100

[0085] <Emulsion stability: Dispersibility of hydrophobized UV scattering agents>

[0086] Evaluation was performed by visually observing the state of the sample after production and by observing the state of the sample after filling the threaded tube with the sample for 2 weeks.

[0087] <Evaluation Criteria>

[0088] A: Stable emulsification is possible, and no separation or aggregation over time is observed.

[0089] B: Stable emulsification is possible, with some separation and aggregation observed over time, but no problem in use.

[0090] C: Stable emulsification is possible, but separation and aggregation are observed over time.

[0091] D: Cannot be emulsified.

[0092] 1. Effect of dosage form on the improvement of UV protection

[0093] Oil-in-water emulsified cosmetics (Test Examples 1 and 2) and water-in-oil emulsified cosmetics (Test Example 3) having the compositions shown in Table 1 below were prepared by conventional methods. The improvement effect of ultraviolet protection was evaluated by the above-mentioned evaluation method.

[0094] [Table 1]

[0095]

[0096] As shown in Table 1, in Test Examples 1 and 2 prepared as oil-in-water emulsions, the ultraviolet protection ability was significantly improved compared to the control sample without the (A) component.

[0097] On the other hand, in Test Example 3 prepared as a water-in-oil emulsion, no improvement in ultraviolet protection was observed.

[0098] 2. Effect of hydrophobic treatment of UV scattering agent on UV protection

[0099] Oil-in-water emulsified cosmetics having the compositions shown in the following Table 2 were prepared by a conventional method. The improvement effect of the ultraviolet protection was evaluated by the above-mentioned evaluation method.

[0100] [Table 2]

[0101]

[0102] Spherical silica in the table: SUNSPHEREL-51S (average particle size 5 μm, manufactured by AGC Si-Tech Co., Ltd.)

[0103] As shown in Table 2, the UV protection ability of Test Example 4 containing a UV scattering agent treated with distearyldimethylammonium chloride, Test Example 5 containing a UV scattering agent treated with polydimethylsiloxane, and Test Example 6 containing a UV scattering agent treated with hydrogenated polydimethylsiloxane was significantly improved compared with the control sample without the (A) component.

[0104] On the other hand, in Test Example 7 in which a UV scattering agent treated with dextrin palmitate was blended, no improvement in UV protection was observed.

[0105] 3. Influence of the amount of water phase thickener

[0106] Oil-in-water emulsified cosmetics having the compositions shown in the following Table 3 were prepared by a conventional method. The emulsion stability was evaluated according to the above-mentioned evaluation method.

[0107] [Table 3]

[0108]

[0109] Spherical silica in the table: SUNSPHEREL-51S (average particle size 5 μm, manufactured by AGC Si-Tech Co., Ltd.)

[0110] As shown in Table 3, Test Example 8 in which the amount of the aqueous phase thickener (dimethylacrylamide / sodium acryloyldimethyltaurate copolymer, succinoglycan) blended was 0.3 mass % or more was excellent in emulsification stability.

[0111] On the other hand, Test Example 9 in which the amount of the aqueous phase thickener blended was less than 0.3% by mass had poor emulsification stability.

[0112] 4. Effect of using in combination with porous spherical powder on the improvement of UV protection

[0113] Oil-in-water emulsified cosmetics having the compositions shown in Table 4 below were prepared by a conventional method. The improvement effect of ultraviolet protection was evaluated according to the above-mentioned evaluation method.

[0114] [Table 4]

[0115]

[0116] Silica in the table: Godd Ball E-6C (manufactured by Suzuki Oil & Fats Industries, Ltd.)

[0117] Test Example 12 in Table 4 is blended with silica listed as a component that exerts an effect of improving ultraviolet protection in Patent Document 1. Test Example 12 blended with silica has improved ultraviolet protection compared to the control sample without silica. In addition, Test Example 10 blended with the acrylic acid (ester) / methacryloyloxyethyl phosphate copolymer as the (A) component of the present invention and silica, additive or synergistic improvement in ultraviolet protection was found compared to Test Example 11 and Test Example 12 blended with either one alone.

Claims

1. An oil-in-water emulsified sunscreen cosmetic comprising: (A) 0.1 to 10% by mass of an acrylic copolymer having a phosphoric acid group, (B) 1 to 40% by mass of a hydrophobized ultraviolet scattering agent, and (C) 0.3% by mass or more of a water phase thickener, The ultraviolet scattering agent is dispersed in the oil layer, The oil-in-water emulsified sunscreen cosmetic does not contain a hollow polymer formed by a styrene / acrylic acid (ester) copolymer, The component (A) is a copolymer comprising an acrylic monomer and an acrylic monomer having a phosphoric acid group, wherein the acrylic monomer is selected from (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acryloyloxy, and 2-ethylhexyl (meth)acrylate, and the acrylic monomer having a phosphoric acid group is an acrylic monomer in which a carboxyl group of acrylic acid or methacrylic acid is esterified by an alkyl group and has a phosphoric acid group in the alkyl group. The component (B) is an ultraviolet scattering agent whose surface has been hydrophobized by one or more selected from silicone compounds and quaternary ammonium salt compounds. The component (C) comprises at least one selected from the group consisting of acrylic acid (esters) / C10-30 alkyl acrylate crosspolymer, carboxyvinyl polymer, agar, xanthan gum, hydroxypropyl methylcellulose stearyl ether, dimethylacrylamide / sodium acryloyldimethyl taurate copolymer and succinoglycan.

2. The cosmetic according to claim 1, wherein The blending mass ratio of the component (A) to the component (C) is 1:7 to 8:

1.

3. The cosmetic according to claim 1, further comprising (D) an ultraviolet absorber.

4. The cosmetic according to claim 1, wherein: The component (C) is a mixture of two or more selected from acrylic acid (esters) / C10-30 alkyl acrylate crosspolymer, carboxyvinyl polymer, agar, xanthan gum, hydroxypropyl methylcellulose stearyl ether, dimethylacrylamide / sodium acryloyldimethyltaurate copolymer and succinoglycan.

5. The cosmetic according to claim 1, further comprising (E) a porous spherical powder having an average particle size of 1 to 4 μm and an oil absorption of 160 ml / 100 g or less.

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