Water-in-oil sunscreen cosmetic composition

Abstract

[Problem] The purpose of the present invention is to provide a water-in-oil sunscreen cosmetic composition which has a low viscosity and a high ultraviolet light shielding effect, while being suppressed in smoothness decrease in a coating film and a powdery look in the finish. [Solution] A water-in-oil sunscreen cosmetic composition according to the present invention contains (A) an ultraviolet absorbent that contains octocrylene and (B) a dihydric alcohol having an IOB of 2.0 or less, and is characterized in that: the addition ratio of ethylhexyl methoxycinnamate relative to the total addition amount of the component (A) is 15% or less; the addition amount of an ultraviolet scattering agent to the total amount of the cosmetic composition is 5% by mass or less; and the viscosity is 1,000 Pa∙s or less.

Description

Water-in-oil sunscreen cosmetics

[0001] The present invention relates to a water-in-oil sunscreen cosmetic composition that has a strong UV protection effect and suppresses powdery texture and white cast in the finished coating.

[0002] To protect the skin from the harmful effects of ultraviolet rays, cosmetics contain UV protection agents such as UV absorbers and UV scattering agents. UV absorbers have advantages such as high transparency, good spreadability on the skin, and resistance to sweating, but can cause undesirable textures such as oiliness and stickiness. On the other hand, UV scattering agents, which are inorganic powder components such as zinc oxide and titanium oxide, reduce the harmful effects of UV rays on the skin by physically scattering and reflecting UV rays. Therefore, they do not have the problems of oiliness and stickiness that UV absorbers do. However, when applied to the skin, cosmetics containing UV scattering agents can cause a whitish cast or a powdery feeling (a feeling of stickiness caused by the powder rubbing against the skin during application). Therefore, in order to achieve a high UV protection effect (high SPF) in sunscreen cosmetics, it is common to combine UV absorbers and UV scattering agents in a balanced manner while taking advantage of their respective advantages.

[0003] On the other hand, when cosmetics applied to the skin are exposed to light or heat, the UV absorbers and other ingredients contained in the cosmetics deteriorate, resulting in a decrease in UV protection efficacy. Therefore, in order to obtain a high UV protection effect in sunscreen cosmetics, a technology is needed to prevent the UV protection effect from being reduced by light or heat.

[0004] Patent Document 1 describes that by blending 5% by mass or more of an amphiphilic substance and an ester oil with an IOB of 0.05 to 0.60 in a cosmetic containing 4-tert-butyl-4'-methoxydibenzoylmethane and ethylhexyl methoxycinnamate, photodegradation of the UV protection ability of 4-tert-butyl-4'-methoxydibenzoylmethane and ethylhexyl methoxycinnamate is suppressed, and a sunscreen cosmetic with high UV protection effect can be obtained.

[0005] Furthermore, Patent Document 2 reports that an amphiphilic substance or moisturizing agent with an IOB value of 5.0 or less has the effect of enhancing the UV protection ability of a UV protection agent after heat is applied to the applied film, rather than immediately after the cosmetic is applied to the skin.

[0006] Therefore, in sunscreen cosmetics, a technique may be required to obtain a high UV protection effect depending on the UV protection agent selected to achieve the desired formulation and feel when used.

[0007] International Publication No. WO 2017 / 057676 International Publication No. WO 2020 / 032246

[0008] In the course of research by the inventors, it was found that a low-viscosity sunscreen cosmetic is needed to realize a formulation that is easy to apply, such as a spray type. However, a problem with low viscosity is that powdery feeling is easily felt, mainly due to the UV scattering agent. Furthermore, if the amount of UV scattering agent is reduced to prevent the powdery feeling and white cast, it becomes difficult to achieve a high UV protection effect. Therefore, an object of the present invention is to provide a low-viscosity water-in-oil sunscreen cosmetic that suppresses powdery feeling in the applied film and white cast in the finished product, while also having a strong UV protection effect.

[0009] As a result of extensive research to solve the above-mentioned problems, the inventors discovered that in cosmetics containing octocrylene, a dihydric alcohol having an IOB of 2.0 or less amplifies the UV protection ability of the UV protection agent when heat is applied to the applied film, and thus completed the present invention.

[0010] That is, the present invention provides a water-in-oil sunscreen cosmetic comprising: (A) an ultraviolet absorber containing octocrylene; and (B) a dihydric alcohol having an IOB of 2.0 or less; wherein the blending ratio of ethylhexyl methoxycinnamate to the total blending amount of (A) is 15% or less; the blending amount of the ultraviolet scattering agent is 5% by mass or less relative to the total amount of the cosmetic; and the viscosity is 1000 mPa s or less.

[0011] By adopting the above-described configuration, the cosmetic composition of the present invention can provide a sunscreen cosmetic that has a strong UV protection effect despite the small amounts of ethylhexyl methoxycinnamate and UV scattering agent blended in. Furthermore, because the amount of UV scattering agent blended in can be reduced, the sunscreen cosmetic composition of the present invention has the advantages of not having a powdery feeling even with a low viscosity, and not causing a white cast after application.

[0012] The cosmetic preparation of the present invention is characterized by containing (A) an ultraviolet absorber containing octocrylene, and (B) a dihydric alcohol having an IOB of 2.0 or less. Each component constituting the cosmetic preparation of the present invention will be described in detail below.

[0013] <(A) Ultraviolet Absorber> The (A) ultraviolet absorber (hereinafter, sometimes simply referred to as "ingredient (A)") incorporated into the cosmetic preparation according to the present invention is an ultraviolet absorber that is typically incorporated into cosmetics for the purpose of absorbing energy through a chemical mechanism and converting it into energy such as heat, thereby preventing ultraviolet rays from affecting skin cells, and essentially contains octocrylene, which is a β,β-diphenylacrylate derivative.

[0014] Examples of ultraviolet absorbers other than octocrylene include benzoic acid derivatives, salicylic acid derivatives, cinnamic acid derivatives, dibenzoylmethane derivatives, benzophenone derivatives, benzylidene camphor derivatives, phenylbenzimidazole derivatives, triazine derivatives, phenylbenzotriazole derivatives, anthranil derivatives, imidazoline derivatives, benzalmalonate derivatives, 4,4-diarylbutadiene derivatives, etc. Specific examples and trade names are listed below, but the present invention is not limited to these.

[0015] Examples of benzoic acid derivatives include ethyl para-aminobenzoate (PABA), ethyl-dihydroxypropyl PABA, ethylhexyl-dimethyl PABA (e.g., "Escarol 507"; ISP), glyceryl PABA, PEG-25-PABA (e.g., "Uvinal P25"; BASF), and diethylaminohydroxybenzoylhexyl hexyl benzoate (e.g., "Uvinal A Plus"; BASF).

[0016] Examples of salicylic acid derivatives include homosalate (Eusolex HMS; Rona / EM Industries), ethylhexyl salicylate or ethylhexyl salicylate (e.g., NeoHeliopan OS; Herman & Reimer), dipropylene glycol salicylate (e.g., Dipsal; Skell), and TEA salicylate (e.g., NeoHeliopan TS; Herman & Reimer).

[0017] Examples of cinnamic acid derivatives include octyl methoxycinnamate or ethylhexyl methoxycinnamate (e.g., "Parsol MCX"; Hoffmann-La Roche), isopropyl methoxycinnamate, isoamyl methoxycinnamate (e.g., "Neo Heliopan E1000"; Herman & Reimer), cinnoxate, DEA methoxycinnamate, diisopropyl methylcinnamate, glyceryl-ethylhexanoate-dimethoxycinnamate, and di-(2-ethylhexyl)-4'-methoxybenzalmalonate.

[0018] An example of a dibenzoylmethane derivative is 4-tert-butyl-4'-methoxydibenzoylmethane (for example, "Parsol 1789"; DSM Nutrition Japan).

[0019] Examples of benzophenone derivatives include benzophenone-1 (e.g., "Uvinal 400"; BASF), benzophenone-2 (e.g., "Uvinal D50"; BASF), benzophenone-3 or oxybenzone (e.g., "Uvinal M40"; BASF), benzophenone-4 (e.g., "Uvinal MS40"; BASF), benzophenone-5, benzophenone-6 (e.g., "Helisorb 11"; Norquay), benzophenone-8 (e.g., "Spectra-Sorb UV-24"; American Cyanamid), benzophenone-9 (e.g., "Uvinal DS-49"; BASF), and benzophenone-12.

[0020] Examples of benzylidene camphor derivatives include 3-benzylidene camphor (e.g., "Mexoryl SD"; Cimex), 4-methylbenzylidene camphor, benzylidene camphorsulfonic acid (e.g., "Mexoryl SL"; Cimex), camphor benzalkonium methosulfate (e.g., "Mexoryl SO"; Cimex), terephthalidenedichamphorsulfonic acid (e.g., "Mexoryl SX"; Cimex), and polyacrylamidomethyl benzylidene camphor (e.g., "Mexoryl SW"; Cimex).

[0021] Examples of phenylbenzimidazole derivatives include phenylbenzimidazole sulfonic acid (for example, "Orthorex 232"; Merck), and disodium phenyldibenzimidazole tetrasulfonate (for example, "Neo Heliopan AP"; Herman & Reimer).

[0022] Examples of triazine derivatives include bisethylhexyloxyphenol methoxyphenyl triazine (e.g., "Tinosorb S"; Ciba Specialty Chemicals), ethylhexyl triazone (e.g., "Uvinal T150"; BASF), diethylhexylbutamido triazone (e.g., "Uvasorb HEB"; Sigma 3 V), 2,4,6-tris(diisobutyl-4'-aminobenzalmalonate)-s-triazine, and 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine.

[0023] Examples of phenylbenzotriazole derivatives include drometrizole trisiloxane (e.g., Silatrizole; Rhodia Chemie), methylenebis(benzotriazolyltetramethylbutylphenol) (e.g., Tinosorb M; Ciba Specialty Chemicals).

[0024] Examples of anthranil derivatives include menthyl anthranilate (for example, "Neo Heliopan MA"; Herman & Reimer).

[0025] Examples of imidazoline derivatives include ethylhexyldimethoxybenzylidene dioxoimidazolidine propionate.

[0026] Examples of benzalmalonate derivatives include polyorganosiloxanes having benzalmalonate functional groups (for example, Polysilicone-15; "Parsol SLX"; DSM Nutrition Japan).

[0027] Examples of 4,4-diarylbutadiene derivatives include 1,1-dicarboxy(2,2'-dimethylpropyl)-4,4-diphenylbutadiene.

[0028] The component (A) used in the present invention may be octocrylene alone, or octocrylene may be used in combination with one or more of the other ultraviolet absorbers described above.

[0029] The blending amount of component (A) is 3 to 40% by mass, and preferably 5 to 30% by mass, of the total amount of the cosmetic. If the blending amount of component (A) is less than 3% by mass, it is difficult to obtain a sufficient UV protection effect, and even if it is blended in more than 40% by mass, an increase in UV protection effect commensurate with the blending amount cannot be expected, and instead stability and usability may be deteriorated, which is not preferable.

[0030] Generally, sunscreen cosmetics often contain ethylhexyl methoxycinnamate to achieve a high SPF. However, in the sunscreen cosmetics of the present invention, ethylhexyl methoxycinnamate tends to hinder the improvement of UV protection ability due to heating when the components (A) and (B) of the present invention are combined. Therefore, in order to maximize the UV protection ability improvement effect of the component (B) described below, the blending ratio of ethylhexyl methoxycinnamate to the total blending amount of the UV absorber (A) is 15% or less by mass, preferably 10% or less. Furthermore, the cosmetics of the present invention do not necessarily need to contain ethylhexyl methoxycinnamate, and therefore embodiments of the cosmetics of the present invention also include embodiments that do not contain ethylhexyl methoxycinnamate.

[0031] Since the sunscreen cosmetic of the present invention can achieve a high UV protection effect by incorporating only component (A), the amount of UV scattering agent such as zinc oxide or titanium oxide may be reduced, or may not be incorporated at all. Here, the UV scattering agent refers to a powder such as zinc oxide or titanium oxide having a refractive index of 1.5 or more, and having an average particle size of 0.1 μm or less. Embodiments of the cosmetic of the present invention include those in which the amount of UV scattering agent is 5% by mass or less, 3% by mass or less, or 1% by mass or less of the total amount of the cosmetic, or those in which no UV scattering agent is contained.

[0032] It has been found that while the incorporation of an ultraviolet scattering agent in the cosmetic composition according to the present invention can enhance the ultraviolet protection ability of the cosmetic composition itself, it is difficult to obtain an enhancement of the ultraviolet protection effect due to heat. Therefore, by reducing the amount of ultraviolet scattering agent in the cosmetic composition according to the present invention, or by not incorporating any ultraviolet scattering agent, the effect of improving the ultraviolet protection ability due to heat can be fully exerted. Furthermore, by reducing the amount of ultraviolet scattering agent in the cosmetic composition according to the present invention, or by not incorporating any ultraviolet scattering agent, it is possible to obtain a sunscreen cosmetic composition that does not cast a white cast or feel powdery when applied to the skin.

[0033] <(B) Dihydric Alcohol> The dihydric alcohol (B) (hereinafter sometimes simply referred to as "component (B)") blended in the cosmetic preparation according to the present invention is one that is commonly used in cosmetics and has an IOB of 2.0 or less. Specific examples include pentylene glycol (IOB = 2.0), dipropylene glycol (IOB = 1.84), hexylene glycol (IOB = 1.8), and ethyl diglycol (IOB = 1.2), with dipropylene glycol being particularly preferred.

[0034] The blending amount of component (B) is 3 to 10% by mass, and preferably 4 to 7% by mass, based on the total amount of the cosmetic. If the blending amount of component (B) is less than 3% by mass, it is difficult to obtain a sufficient improvement in UV protection ability, and if it exceeds 10% by mass, stability may decrease or the feel in use may become sticky or poor.

[0035] The sunscreen cosmetic according to the present invention has a viscosity of 1,000 mPa·s or less. The lower limit of the viscosity is preferably 200 mPa·s or more. Therefore, the preferred viscosity range is 200 to 1,000 mPa·s. Note that the viscosity in this specification is a value measured at 30°C using a B-type viscometer.

[0036] In the sunscreen cosmetic according to the present invention, in order to further enhance the UV protection ability of the cosmetic itself, hydrophobized silica (C) may be further blended in addition to the components (A) and (B). In the present invention, by blending the component (A) in combination with the components (B) and (C), it is possible to enhance the UV protection ability of the cosmetic before the application of heat.

[0037] The hydrophobic silica (C) (hereinafter sometimes referred to simply as "component (C)") blended in the cosmetic composition of the present invention is silica (silicic anhydride) commonly used in the field of cosmetics, and has a hydrophobic particle surface, an average particle diameter of 2 to 8 μm, and a specific surface area of ​​200 to 350 m. ２ / g, refers to a material having an oil absorption of 100 ml / 100 g or more, preferably 100 to 200 ml / 100 g. Among these, porous spherical silica is preferred.

[0038] The method for hydrophobizing the particle surface of (C) hydrophobized silica is not particularly limited, but from the viewpoint of obtaining high UV protection performance, it is preferable to use silicones such as methylhydrogenpolysiloxane and dimethylpolysiloxane as the hydrophobizing agent. Examples of such hydrophobized silica include SA-SB-150 and SA-SB-300 (manufactured by Miyoshi Chemicals Co., Ltd.).

[0039] The amount of component (C) blended is not essential since it is an optional component in the cosmetic of the present invention, but if it is blended, it is preferably blended to an extent that the effect of blending is recognized and to an extent that an excessive blending amount does not cause adverse effects such as impairing the feel of use. The preferred blending amount of component (C) in the cosmetic of the present invention is approximately 1 to 10% by mass or 2 to 8% by mass of the total amount of the cosmetic.

[0040] In the cosmetic composition according to the present invention, by blending the dihydric alcohol (B) and the hydrophobized silica (C) in combination, a higher ultraviolet protection effect can be obtained than by blending the hydrophobized silica (C) alone.

[0041] In addition to the components (A) to (C), the cosmetic of the present invention may contain other components commonly used in cosmetics, provided that the effects of the present invention are not impaired. For example, surfactants, oils, powder components, pH adjusters, chelating agents, preservatives, antioxidants, medicines, alcohols, coloring agents, pigments, etc. may be appropriately blended as needed.

[0042] The cosmetic composition according to the present invention can be provided not only as a sunscreen cosmetic composition, but also as a skin care cosmetic composition such as a lotion having a sunscreen effect, a makeup base, a hair cosmetic composition (including various hair products such as hair sprays and hair treatments for protecting hair and scalp from ultraviolet rays), and the like.

[0043] Furthermore, although the container form of the present invention is not limited, it is suitable for storing aerosol cosmetic concentrates. Aerosol cosmetics refer to a pressure-resistant valve canister filled with a concentrate that is a water-in-oil emulsion and a propellant such as liquefied petroleum gas, dimethyl ether, nitrogen, oxygen, carbon dioxide, or chlorofluorocarbon. Depending on the intended use, the form can be adjusted to a spray (mist), foam (foam), or other form, but a spray form is preferred from the viewpoint of ease of application to skin and hair.

[0044] The sunscreen cosmetic composition according to the present invention has the property that the ultraviolet protection effect (also referred to as "ultraviolet protection capability") of the coating film is improved by heat. Here, "ultraviolet protection effect is improved by heat" can be roughly defined as follows.

[0045] A predetermined amount of a cosmetic sample is dropped onto a measurement plate, applied to a predetermined area, and dried to form a coating film. The absorbance of the coating film is measured over a range of 280 to 400 nm using a spectrophotometer or the like, and the integrated absorbance value of the coating film is determined based on the absorbance of an uncoated measurement plate. Next, the measurement plate on which the coating film has been formed is heated under predetermined conditions, and the absorbance of the coating film is measured after it has returned to room temperature, and the integrated absorbance value is determined in the same manner. The rate of change in the integrated absorbance value before and after heat treatment (rate of absorbance change) is calculated according to the following formula: Rate of absorbance change (%) = (integrated absorbance value after heat treatment) / (integrated absorbance value before heat treatment) × 100. A rate of change exceeding 100% is defined as an improvement (enhancement) in UV protection effect.

[0046] Instead of the integrated absorbance value, the absorbance at a single wavelength (ultraviolet region), the critical wavelength, or the SPF or UVAPF (or "PFA") calculated based on the measured absorbance may be used as an index. The temperature to which the coating film is heated is preferably in the range of 30°C to 70°C, and can be, for example, 32°C or higher, 35°C or higher, 37°C or higher, or 40°C or higher, and can be 65°C or lower, 60°C or lower, 55°C or lower, or 50°C or lower. Heating temperatures exceeding 70°C can cause problems such as dissolution of the resin measurement plate. In order to accurately evaluate the effects of heat, the heating time is preferably 1 minute or longer, more preferably 10 minutes or longer. The upper limit of the heating time is not particularly limited, but is usually 60 minutes or shorter, preferably 30 minutes or shorter.

[0047] In the cosmetic preparation of the present invention, the UV protection ability is improved by combining the components (A) and (B), and therefore the incorporation of an amphiphilic substance or moisturizer other than component (B) with an IOB value of 5.0 or less, such as that reported in Patent Document 2, is not essential. In the cosmetic preparation of the present invention, the amphiphilic substance or moisturizer with an IOB value of 5.0 or less may be incorporated in an amount of less than 5% by mass, less than 3% by mass, less than 1% by mass, or less than 0.1% by mass relative to the total amount of the cosmetic preparation, or may not be incorporated at all. Specifically, the amphiphilic substance or moisturizer other than component (B) of the present invention with an IOB value of 5.0 or less refers to those shown in (1) and (2) below.

[0048] (1) A polyoxyalkylene-polyoxyethylene copolymer dialkyl ether represented by the following formula (I): R １ O-[(AO) ｍ (EO) ｎ ]-R ２ (I) (In formula (I), AO represents an oxyalkylene group having 3 to 4 carbon atoms, EO represents an oxyethylene group, and R １ and R ２ each independently represents a hydrocarbon group having 1 to 4 carbon atoms or a hydrogen atom, and 1≦m≦70, and 1≦n≦70. Specific examples include PEG / PPG-9 / 2 dimethyl ether, PEG / PPG-17 / 4 dimethyl ether, PEG / PPG-14 / 7 dimethyl ether, PEG / PPG-11 / 9 dimethyl ether, PEG / PPG-55 / 28 dimethyl ether, PEG / PPG-36 / 41 dimethyl ether, PEG / PPG-6 / 3 dimethyl ether, PEG / PPG-8 / 4 dimethyl ether, PEG / PPG-6 / 11 dimethyl ether, and PEG / PPG-14 / 27 dimethyl ether.

[0049] (2) Polyalkylene glycol represented by the following formula (II): HO(RO) ｐ H (II) (in formula (II), RO represents an oxyalkylene group having 2 to 4 carbon atoms, and p is 3 to 500), and a polyhydric alcohol selected from butylene glycol, diglycerin, propanediol, erythritol, xylitol, methyl gluceth-10, and sorbitol. Specific examples of the polyalkylene glycol represented by formula (II) include polyethylene glycols 150 to 23,000, such as polyethylene glycol 300, polyethylene glycol 400, polyethylene glycol 1500, and polyethylene glycol 20,000.

[0050] The dihydric alcohol (B) of the present invention partially overlaps with, but does not completely match, the amphiphilic substance described in Patent Document 1 and the amphiphilic substance and moisturizer described in Patent Document 2. For example, it has been confirmed that dibutylene glycol (IOB=2.4), which exhibits a photodegradation suppression effect in Patent Document 1, and PEG / PPG-9 / 2 dimethyl ether and polyethylene glycol 300, which exhibit an ultraviolet protection ability improvement effect due to heat in Patent Document 2, are unlikely to exhibit an ultraviolet protection ability improvement effect due to heat in the present invention.

[0051] Aspects of the cosmetic preparation according to the present invention include those that do not contain the polyoxyalkylene-polyoxyethylene copolymer dialkyl ether represented by formula (I), the polyalkylene glycol represented by formula (II), butylene glycol, diglycerin, propanediol, erythritol, xylitol, methyl gluceth-10, or sorbitol.

[0052] In order to obtain an improved UV protection effect, the cosmetic preparation according to the present invention may not contain an ester oil having an IOB value of 0.3 or greater. Accordingly, embodiments of the cosmetic preparation according to the present invention include those in which the amount of ester oil having an IOB value of 0.3 or greater is less than 5% by mass, less than 3% by mass, or less than 1% by mass of the total amount of the cosmetic preparation, and those in which no ester oil having an IOB value of 0.3 or greater is contained. Specific examples of ester oils having an IOB value of 0.3 or more include propylene glycol dicaprylate (IOB=0.32), di-2-ethylhexyl succinate (IOB=0.32), pentaerythrite tetra-2-ethylhexanoate (IOB=0.35), glyceryl tri-2-ethylhexanoate (IOB=0.36), pentaerythrite tetraoctanoate (IOB=0.35), diisopropyl sebacate (IOB=0.40), and tripropylene glycol dineopentanoate (IOB=0.52).

[0053] In order to obtain an improved UV protection effect, the cosmetic preparation according to the present invention may not contain an oil phase thickener selected from dextrin fatty acid esters, sucrose fatty acid esters, solid or semi-solid hydrocarbon oils, organically modified clay minerals, and fatty acids or their salts. Accordingly, embodiments of the cosmetic preparation according to the present invention include those in which the amount of the oil phase thickener selected from dextrin fatty acid esters, sucrose fatty acid esters, solid or semi-solid hydrocarbon oils, organically modified clay minerals, and fatty acids or their salts is less than 3% by mass, less than 1% by mass, less than 0.5% by mass, or less than 0.1% by mass of the total amount of the cosmetic preparation, as well as those in which the oil phase thickener is not contained. Furthermore, in order to obtain an improved UV protection effect, the cosmetic preparation according to the present invention may not contain a dextrin fatty acid ester and / or an organically modified clay mineral. Therefore, embodiments of the cosmetic according to the present invention include those in which the blending amount of the dextrin fatty acid ester and / or the organically modified clay mineral is less than 3 mass%, less than 1 mass%, less than 0.5 mass%, or less than 0.1 mass% of the total amount of the cosmetic, and those in which the dextrin fatty acid ester and the organically modified clay mineral are not contained. Specific examples of dextrin fatty acid esters include dextrin palmitate, and specific examples of organically modified clay minerals include dimethyl distearyl ammonium hectorite (disteardimonium hectorite).

[0054] The present invention will be described in further detail below with reference to examples, but the present invention is not limited thereto. Unless otherwise specified, the blending amount is expressed as mass % relative to the system in which the component is blended. Before describing each example in detail, the evaluation methods used will be described.

[0055] 1. Measurement of UV protection ability of cosmetics Each cosmetic (sample) was applied at 2 mg / cm to a measurement plate (S plate) (5 x 5 cm V-groove PMMA plate, SPFMASTER-PA01). ２ The absorbance of the resulting coating film was measured at 310 nm using a U-3500 model recording spectrophotometer (manufactured by Hitachi, Ltd.). A higher measured value indicates a higher UV protection ability.

[0056] 2. Measurement of the rate of change in UV protection ability due to heat A cosmetic material (sample) of each example was applied at 2 mg / cm to a measurement plate (S plate) (5 x 5 cm V-groove PMMA plate, SPFMASTER-PA01). ２ The coating was applied in an amount of 100 ml, applied with a finger for 60 seconds, and allowed to dry for 15 minutes. The absorbance of the resulting coating was measured using a U-3500 model self-recording spectrophotometer (Hitachi, Ltd.). Using an uncoated plate as a control, the absorbance (Abs) was calculated using the following formula. The measured values ​​from 280 nm to 400 nm were integrated to determine the absorbance at 310 nm. Abs = -log(T / To), where T is the transmittance of the sample and To is the transmittance of the uncoated plate. The plate with the coating was then placed in a thermostatic chamber and heated at 37°C for 30 minutes. The absorbance at 310 nm was determined in the same manner as above. The rate of change in absorbance (thermal change rate) before and after thermal irradiation for each sample was calculated according to the following formula: Thermal change rate (%) = [(absorbance at 310 nm after heat treatment) / (absorbance at 310 nm before heat treatment)] x 100 When the thermal change rate exceeds 100%, it is evaluated that an improved UV protection effect has been achieved.

[0057] Water-in-oil sunscreen cosmetics having the compositions shown in Tables 1 and 2 below were prepared by conventional methods. Specifically, powder was dispersed in an oily component mixed using a homomixer, and then a well-mixed aqueous component was added to obtain the cosmetics. The UV protection ability of the prepared cosmetics was measured according to the evaluation method described above. The results are also shown in the tables.

[0058]

[0059]

[0060] As shown in Table 2, neither the cosmetic composition of Comparative Example 1, which did not contain octocrylene, nor the cosmetic composition of Comparative Example 2, which did not contain component (B) of the present invention, exhibited any improvement in UV protection ability due to heat. Furthermore, when a dihydric alcohol with an IOB of 2.4 (Comparative Example 3), PEG / PPG-9 / 2 dimethyl ether (Comparative Example 4), or polyethylene glycol 300 (Comparative Example 5) was used instead of component (B) of the present invention, no improvement in UV protection ability due to heat was observed.

[0061] On the other hand, as shown in Table 1, the cosmetics of Examples 1, 2, and 4, which contained components (A) and (B) of the present invention, exhibited a high UV protection effect due to heat. Furthermore, the cosmetic of Example 3, which contained hydrophobized silica (methylpolysiloxane-treated silica) (C) in addition to components (A) and (B) of the present invention, exhibited high UV protection, even though the total amount of UV absorber was the same as that of the cosmetics of Examples 1, 2, and 4. This indicates that the UV protection of the cosmetic was enhanced by the combination of components (B) and (C) of the present invention. Furthermore, a comparison of Example 2, which contained silica, with Example 3, which contained hydrophobized silica (C), showed that a significant improvement in UV protection was achieved when hydrophobized silica (C) was added.

[0062] Next, by varying the amounts of the UV scattering agent and ethylhexyl methoxycinnamate, water-in-oil sunscreen cosmetics having the compositions shown in Table 3 were prepared by conventional methods. Similarly, the UV protection ability of the prepared cosmetics was measured according to the evaluation method described above. The results are also shown in the table.

[0063]

[0064] As shown in Table 3, when the blending amount of the UV scattering agent was 10% by mass relative to the total amount of the cosmetic (Comparative Example 6), the UV protection ability of the cosmetic itself was high, but the UV protection ability improvement effect due to heat was not obtained. Furthermore, the cosmetic of Comparative Example 6 caused a whitish cast after application, and a powdery feeling was felt, resulting in a poor usability. Furthermore, when the blending ratio of ethylhexyl methoxycinnamate relative to the total blending amount of component (A) of the present invention was increased, the UV protection ability improvement effect due to heat became difficult to obtain (Comparative Example 7). On the other hand, as shown in Examples 3, 5, and 6, in the cosmetic of the present invention, when the blending amount of the UV scattering agent was low and the blending ratio of ethylhexyl methoxycinnamate relative to the total blending amount of the UV absorbers was low, higher UV protection ability was obtained and the UV protection ability improvement effect due to heat was also obtained.

Claims

1. A water-in-oil sunscreen cosmetic comprising: (A) an ultraviolet absorber containing octocrylene; and (B) a dihydric alcohol having an IOB of 2.0 or less; wherein the blending ratio of ethylhexyl methoxycinnamate to the total blending amount of (A) is 15% or less; the blending amount of ultraviolet scattering agent is 5% by mass or less relative to the total amount of the cosmetic; and the viscosity is 1000 mPa·s or less.

2. The water-in-oil sunscreen cosmetic composition according to claim 1, which does not contain ethylhexyl methoxycinnamate.

3. The water-in-oil sunscreen cosmetic composition according to claim 1 or 2, which does not contain an ultraviolet scattering agent.

4. The water-in-oil sunscreen cosmetic according to claim 1, wherein component (B) is dipropylene glycol.

5. The water-in-oil sunscreen cosmetic according to claim 1, further comprising (C) hydrophobized silica.

6. The water-in-oil sunscreen cosmetic composition according to claim 1, which is an aerosol cosmetic composition.

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