Water-in-oil sunscreen cosmetics

Abstract

To provide water-in-oil sunscreen cosmetics that acquire improved UV protection effect, are not sticky, can be spread all over the body regardless of skin dryness, and form a cosmetic film with rubbing resistance.SOLUTION: Water-in-oil sunscreen cosmetics contain the following component (A) of 0.5-10 mass%, component (B) of 5-35 mass%, component (C) of 1-30 mass%, and component (D) of 5-35 mass%. (A): an alkylene oxide derivative represented by the formula (1), (B): a UV scattering agent, (C) an ester oil that is liquid at 25°C, and (D) a linear silicone oil with a kinematic viscosity of 1-20 mm2 / s at 25°C (in the formula (1), AO denotes a C3-4 oxyalkylene group, EO denotes an oxyethylene group, a denotes a number from 0 to 50, b denotes a number from 1 to 50, a+b≥10, and 0≤a / b≤2).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a water-in-oil sunscreen cosmetic. [Background technology]

[0002] Sunscreen cosmetics protect the skin from UV damage and are applied to a wide range of areas of the body, including the face, neck, hands, arms, and legs. Therefore, they are required to have a pleasant texture and feel, such as a lack of stickiness and ease of application, as well as good UV protection and water resistance and abrasion resistance to maintain that effect. Water-in-oil sunscreen cosmetics have the advantage of being less sticky and water-resistant due to the oily external phase. However, water-in-oil sunscreen cosmetics tend to be sticky, and the more UV protection agents are added to achieve high UV protection, the more sticky the product becomes and the more difficult it is to spread. Furthermore, sunscreens composed of low-viscosity oils to reduce stickiness have the drawback of stickiness when applied to dry skin caused by winter air or air conditioning, making them particularly difficult to spread.

[0003] For example, Patent Document 1 proposes a water-in-oil emulsion cosmetic that has excellent UV protection effects and is not sticky or oily, by containing an organic UV protection agent, zinc oxide, a polymer whose constituent units are a hydrophilic segment having N-acylalkyleneimine repeating units and an organopolysiloxane segment, an acrylate ester resin powder, a silicone resin, silicone oil, and water.

[0004] Patent Document 2 proposes a water-in-oil emulsion sunscreen cosmetic that contains a specific benzotriazole-type ultraviolet absorber, a surfactant, an electrolyte, and a specific silicone compound, and thus has high ultraviolet protection power, spreads easily upon application, and is not sticky.

[0005] One way to maintain UV protection is to improve the abrasion resistance of sunscreen cosmetics. In recent years, the number of occasions when wearing masks to prevent infectious diseases has increased. To prevent differences in the degree of sunburn on the face depending on whether or not a mask is worn, it is necessary to apply sunscreen under the mask as well. However, when adjusting the mask or putting it on or taking it off, pressing the mask with your fingers or wearing a tight-fitting mask can easily cause the mask to rub against the face, resulting in the sunscreen cosmetics coming off. Therefore, there is a demand for a cosmetic film that is resistant to abrasion.

[0006] Patent Document 3 proposes a water-in-oil emulsion cosmetic for sunscreen that is less sticky and has excellent abrasion resistance, by combining an alkyl-modified silicone wax with a melting point of 60°C or higher, a hydrophobic UV scattering agent, and water. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-69282 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-247897 [Patent Document 3] Japanese Patent Publication No. 2020-97576 Summary of the Invention [Problem to be solved by the invention]

[0008] Patent Documents 1 and 2 propose water-in-oil sunscreen cosmetics with reduced stickiness. However, according to studies by the present inventors, the water-in-oil emulsion cosmetic proposed in Patent Document 1 was insufficient in terms of ease of spreadability. Furthermore, the water-in-oil emulsion sunscreen cosmetic proposed in Patent Document 2 was insufficient in terms of ease of spreadability on dry skin and the durability of high UV protection effect.

[0009] Furthermore, Patent Document 3 proposes a water-in-oil emulsion sunscreen cosmetic that is expected to have reduced stickiness and improved wear resistance, thereby improving durability. However, according to studies by the present inventors, the water-in-oil emulsion sunscreen cosmetic proposed in Patent Document 3 was insufficient in terms of ease of application.

[0010] In view of the above problems, the present invention aims to provide a water-in-oil sunscreen cosmetic composition that has an enhanced ultraviolet protection effect due to an SPF-enhancing component, is non-sticky, can be spread over the entire body even on dry skin, and forms a cosmetic film that is resistant to rubbing. [Means for solving the problem]

[0011] As a result of intensive research conducted in light of the above-mentioned problems, the present inventors have discovered that a water-in-oil sunscreen cosmetic that can solve the above-mentioned problems can be obtained by combining an ultraviolet scattering agent, a specific oil agent, and an alkylene oxide derivative having a specific structure in specified blending amounts, and have thus completed the present invention.

[0012] That is, the present invention relates to a water-in-oil sunscreen cosmetic composition containing 0.5 to 10 mass% of the following component (A), 5 to 35 mass% of component (B), 1 to 30 mass% of component (C), and 5 to 35 mass% of component (D): (A) An alkylene oxide derivative represented by the following formula (1):

[0013] [ka]

[0014] In formula (1), AO represents an oxyalkylene group having 3 to 4 carbon atoms, EO represents an oxyethylene group, a represents the number of moles of the oxyalkylene group having 3 to 4 carbon atoms added, b represents the number of moles of the oxyethylene group added, a represents a number from 0 to 50, b represents a number from 1 to 50, a+b≧10, and 0≦a / b≦2. When the alkylene oxide derivative represented by formula (1) has both the oxyalkylene group having 3 to 4 carbon atoms and the oxyethylene group, the oxyalkylene group having 3 to 4 carbon atoms and the oxyethylene group are added in a random or block manner, and in the case of block addition, the order of arrangement is not important. (B) UV scattering agent (C) Ester oil that is liquid at 25°C (D) Kinematic viscosity at 25°C is 1 to 20 mm 2 / s linear silicone oil [Effects of the Invention]

[0015] The water-in-oil sunscreen cosmetic of the present invention has an enhanced ultraviolet protection effect due to the SPF-enhancing component, is non-sticky, can be spread all over the body even on dry skin, and forms a cosmetic film that is resistant to rubbing. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described.

[0017] In this specification, numerical ranges defined using the symbol "to" are inclusive of the numerical values ​​at both ends (upper and lower limits) of the symbol "to." For example, "2 to 5" means 2 or more and 5 or less.

[0018] The sunscreen cosmetic of the present invention contains at least component (A), component (B), component (C) and component (D). Each component will be explained below.

[0019] [Component (A)] Component (A) is an alkylene oxide derivative represented by formula (1).

[0020] [ka]

[0021] In formula (1), AO represents an oxyalkylene group having 3 to 4 carbon atoms, EO represents an oxyethylene group, a represents the number of moles of the oxyalkylene group having 3 to 4 carbon atoms added, b represents the number of moles of the oxyethylene group EO added, a represents a number from 0 to 50, b represents a number from 1 to 50, a+b≧10, and 0≦a / b≦2. The oxyalkylene group having 3 to 4 carbon atoms and the oxyethylene group are added in a random or block manner, and in the case of block addition, the order of arrangement is not important.

[0022] By setting a to 50 or less, the SPF improvement effect and ease of spreading can be improved, stickiness can be reduced, and the resistance of the cosmetic film to rubbing can be improved. Therefore, a is set to 0 to 50, preferably 0 to 40, and most preferably 0 to 30.

[0023] By making b 1 or greater, the SPF can be improved, the ease of application to dry skin can be improved, the resistance to rubbing of the cosmetic film can be improved, and stickiness can be reduced. Furthermore, by making b 50 or less, stickiness can be reduced and the resistance to rubbing of the cosmetic film can be improved. Therefore, b is set to 1 to 50, with 10 to 40 being preferred, and 10 to 30 being most preferred.

[0024] By making a+b 10 or more, it is possible to improve the ease of spreading on dry skin and the resistance to rubbing of the cosmetic film. It also improves the SPF improvement effect. Therefore, a+b is set to 10 or more, and 20 or more is most preferable. There is no particular upper limit for a+b, but from the viewpoint of improving the SPF improvement effect, reducing stickiness, and improving the resistance to rubbing of the cosmetic film, it is preferable to make it 50 or less.

[0025] When a is greater than 0, the oxyalkylene groups and oxyethylene groups having 3 to 4 carbon atoms are added randomly or in a block form. When added in a block form, the order of arrangement is not important. When a is greater than 0, the oxyalkylene groups and oxyethylene groups having 3 to 4 carbon atoms are preferably added randomly.

[0026] By setting the a / b ratio to 2 or less, stickiness can be reduced and the SPF improvement effect, resistance to rubbing of the cosmetic film, and ease of spreading can be improved. Therefore, the a / b ratio is set to 2 or less, and 1.2 or less is most preferable. The lower limit of the a / b ratio is 0, but it may be set to 0.3 or more.

[0027] Examples of the oxyalkylene group having 3 to 4 carbon atoms include an oxypropylene group and an oxybutylene group, with an oxypropylene group being the most preferred. The alkylene oxide derivative represented by formula (1) may have either an oxypropylene group or an oxybutylene group, or both. When both are present, the oxypropylene group and the oxybutylene group may be in either a random or block form. When added in a block form, the order of arrangement is not important.

[0028] Component (A) has a monoether structure in which an alkylene oxide is added to the first hydroxyl group of the three hydroxyl groups of glycerin. The monoether purity is 80% or more, preferably 90% or more, and more preferably 95% or more. There is no particular upper limit to the monoether purity, but it can be 100% or less.

[0029] Monoether purity is 1 It can be calculated from the following formula using the peak integral value obtained by H-NMR measurement.

[0030]

number

[0031] x represents the peak integral at approximately 2.4 ppm, which is derived from the methylene groups at positions 1 and 3 of glycerin to which ethylene oxide has been added, when the peak integral at approximately 3.3 ppm, which is derived from the methine group at position 2 of glycerin and which is detected only in the monoether form, is set to 1. However, if the peak integral at approximately 3.3 ppm, which is derived from the methine group at position 2 of glycerin in the monoether form, cannot be detected, the purity of the monoether form is set to 0.

[0032] The alkylene oxide derivative represented by formula (1) can be produced by a known method. An alkylene oxide is addition-polymerized with an alkyl alcohol, such as isopropylidene glycol in which all but the primary hydroxyl group of glycerin have been protected, in the presence of an alkali catalyst at 50 to 160°C and 0.5 MPa (gauge pressure) or less. When using two or more alkylene oxides, in the case of a random alkylene oxide, the two or more alkylene oxides are mixed together before addition polymerization. In the case of a block alkylene oxide, EO may be polymerized after AO, or EO may be polymerized after AO. Subsequently, an acid such as hydrochloric acid, phosphoric acid, or acetic acid is added to deacetalize the mixture. The excess acid is neutralized with a base such as potassium hydroxide or sodium hydroxide, and the water and neutralization salt are then removed to obtain the alkylene oxide derivative.

[0033] The concentration of component (A) added is 0.5 to 10% by mass, preferably 1 to 8% by mass, and more preferably 1.5 to 5% by mass, based on the total mass of the water-in-oil sunscreen cosmetic. Increasing the content of component (A) can provide a sufficient SPF improvement and improve the ease of spreading on the skin. Not including an excessive content of component (A) reduces the likelihood of uneven application, stickiness, and vulnerability to rubbing.

[0034] [Component (B)] Component (B) is an ultraviolet scattering agent. An ultraviolet scattering agent refers to a substance that can reflect and scatter ultraviolet rays to protect the skin and the like from ultraviolet rays. Examples of ultraviolet scattering agent materials that can be used in the present invention include titanium oxide, zinc oxide, iron oxide, zirconium oxide, and aluminum oxide. Examples of ultraviolet scattering agents include those obtained by microparticulating these materials or by compounding them. The ultraviolet scattering agent preferably contains one or two types selected from titanium oxide and zinc oxide.

[0035] The titanium oxide and zinc oxide used as the UV scattering agent may be titanium oxide and zinc oxide that are commonly used in cosmetics. Preferably, titanium oxide and zinc oxide with better dispersibility, for example, titanium oxide and zinc oxide that have been surface-treated, specifically hydrophobized, by a known method as needed, can be contained in the skin composition.

[0036] Examples of surface treatment methods include silicone treatment with methylhydrogenpolysiloxane, methylpolysiloxane, or the like; fluorine treatment with perfluoroalkyl phosphate ester, perfluoroalcohol, or the like; amino acid treatment with N-acylglutamic acid, or the like; alkylalkoxysilane treatment with octyltriethoxysilane, octyltrimethoxysilane, or the like; lecithin treatment; metal soap treatment; fatty acid treatment; and alkyl phosphate ester treatment.

[0037] Component (B) is preferably microparticulated to an average primary particle size of 8 to 80 nm, more preferably 10 to 20 nm.

[0038] The concentration of the UV scattering agent added is 5 to 35% by mass, preferably 10 to 30% by mass, and more preferably 15 to 25% by mass, based on the total mass of the water-in-oil sunscreen cosmetic. By increasing the content of component (B), sufficient UV protection effect as a sunscreen can be obtained, and by not including an excessive content of component (B), the cosmetic can be easily spread, is less likely to become uneven, and adverse effects on the feel when used, such as a rough feeling or a white cast, are less likely to occur.

[0039] [Component (C)] Component (C) is an ester oil that is liquid at 25° C. The ester oil that is liquid at 25° C. used in the present invention is preferably an ester oil of a linear or branched, saturated or unsaturated fatty acid or hydroxy fatty acid having 8 to 28 carbon atoms with a linear or branched, saturated or unsaturated alcohol having 2 to 28 carbon atoms, and examples thereof include isononyl isononanoate, isotridecyl isononanoate, isopropyl myristate, myristyl myristate, octyldodecyl myristate, isopropyl palmitate, isopropyl isostearate, 2-ethylhexyl hydroxystearate, butyl stearate, neopentyl glycol dicaprate, cetyl 2-ethylhexanoate, and 2-ethylhexanoic acid. Examples of suitable oleic acid esters include pentaerythrityl, isostearyl isostearate, trimethylolpropane triisostearate, neopentyl glycol di-2-ethylhexanoate, trimethylolpropane tri-2-ethylhexanoate, pentaerythritol tetra-2-ethylhexanoate, cetyl octanoate, oleyl oleate, octyldodecyl oleate, decyl oleate, ethyl oleate, octyldodecyl erucate, isocetyl stearate, butyl stearate, diisopropyl sebacate, 2-ethylhexyl palmitate, 2-hexyldecyl palmitate, and 2-heptylundecyl palmitate.

[0040] Preferred are isopropyl myristate, 2-ethylhexyl hydroxystearate, diisopropyl sebacate, neopentyl glycol dicaprate, and isononyl isononanoate, which are obtained by reacting a saturated or unsaturated fatty acid or hydroxy fatty acid having 8 to 10 carbon atoms with a saturated or unsaturated alcohol having 3 to 10 carbon atoms, and from the viewpoint of increasing the resistance to rubbing of the cosmetic film, isopropyl myristate and 2-ethylhexyl hydroxystearate are even more preferred.

[0041] The concentration of the ester oil that is liquid at 25° C. is 1 to 30% by mass, preferably 3 to 25% by mass, and more preferably 5 to 20% by mass, based on the total mass of the water-in-oil sunscreen cosmetic. Increasing the content of component (C) makes it easier to spread over a wide area and ensures that the cosmetic film is sufficiently resistant to rubbing, while not including an excessive amount of component (C) makes it less sticky and easier to spread.

[0042] [Component (D)] Component (D) has a kinematic viscosity of 1 to 20 mm at 25°C. 2 It is a linear silicone oil with a kinematic viscosity of 1 to 20 mm / s at 25°C. 2 Examples of the linear silicone oil of / s include dimethylpolysiloxane (dimethicone), methylphenylpolysiloxane, etc. Dimethylpolysiloxane is preferably used.

[0043] Kinematic viscosity at 25°C is 1 to 20 mm 2 The concentration of the linear silicone oil in the formula (I) is 5 to 35% by mass, preferably 10 to 30% by mass, and more preferably 15 to 25% by mass, based on the total mass of the water-in-oil sunscreen cosmetic. By increasing the content of component (D), it is possible to ensure sufficient ease of spreading over a wide area, and by not including an excessive amount of component (D), it is possible to increase resistance to rubbing and improve the stability of the cosmetic.

[0044] The combined concentration of components (C) and (D) in the present invention is preferably 10 to 45% by mass, more preferably 20 to 35% by mass, based on the total mass of the water-in-oil sunscreen cosmetic. The value calculated by component (C) / [component (C) + component (D)] is preferably 0.10 to 0.70, more preferably 0.15 to 0.60. A value of component (C) / [component (C) + component (D)] of 0.10 or higher provides sufficient resistance to rubbing and ease of spread on dry skin, while a value of 0.60 or lower reduces stickiness and makes the cosmetic easier to spread.

[0045] [Other ingredients] The water-in-oil sunscreen cosmetic of the present invention typically contains water in addition to the above components (A) to (D). Examples of water include purified water, tap water, industrial water, and deionized water. The concentration of water added in the present invention is typically 5 to 60% by mass, preferably 10 to 55% by mass, and more preferably 15 to 50% by mass, based on the total mass of the water-in-oil sunscreen cosmetic.

[0046] In addition to the above components (A) to (D) and water, the sunscreen cosmetic of the present invention may contain additives used in cosmetics, quasi-drugs, pharmaceuticals, etc., as needed, within the scope of not impairing the object of the present invention.

[0047] Such additives include, for example, ultraviolet absorbers, surfactants, etc. Examples of ultraviolet absorbers include amyl paradimethylbenzoate, 2-ethylhexyl paradimethylaminobenzoate, ethyl 4-[N,N-di(2-hydroxypropyl)amino]benzoate, hexyl diethylaminohydroxybenzoylbenzoate, 2-ethylhexyl salicylate, 2-ethoxyethyl paramethoxycinnamate, 2-ethylhexyl paramethoxycinnamate, glyceryl di-paramethoxycinnamate mono-2-ethylhexanoate, 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)alininino]-1,3,5-triazine, octocriptine, methylparaben ... Examples of the ultraviolet absorber include hexyl diethylaminohydroxybenzoylbenzoate, 4-t-butyl-4'-methoxydibenzoylmethane, dimethicone diethyl benzalmalonate, and bisethylhexyloxyphenol methoxyphenyl triazine. Preferred are diethylaminohydroxybenzoyl hexyl benzoate, 2-ethylhexyl paramethoxycinnamate, 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine, octocrylene, 4-t-butyl-4'-methoxydibenzoylmethane, and bisethylhexyloxyphenol methoxyphenyl triazine. More preferred are diethylaminohydroxybenzoyl hexyl benzoate, 2-ethylhexyl paramethoxycinnamate, 4-t-butyl-4'-methoxydibenzoylmethane, and bisethylhexyloxyphenol methoxyphenyl triazine. One or more of these ultraviolet absorbers can be appropriately selected and used as needed.

[0048] The surfactant is preferably one with an HLB of 3 to 7, such as PEG-9 polydimethylsiloxyethyl dimethicone, PEG-10 dimethicone, polyglyceryl-2 stearate, etc. PEG-9 polydimethylsiloxyethyl dimethicone is preferred.

[0049] When the water-in-oil sunscreen cosmetic of the present invention contains other ingredients, the content of the other ingredients relative to the total mass of the water-in-oil sunscreen cosmetic is preferably 30% by mass or less, and more preferably 0.01% by mass to 20% by mass.

[0050] The water-in-oil sunscreen cosmetic of the present invention is formed by emulsifying an oily component and an aqueous phase component, and can be produced by a commonly used method, for example, by mixing and dissolving oily components such as components (C) and (D), adding component (B) while stirring, and then adding and emulsifying an aqueous phase component prepared by mixing and dissolving component (A) and the like in water.

[0051] The water-in-oil sunscreen cosmetic of the present invention can be provided in various forms according to the intended use, for example, as a milky lotion, cream, gel, etc. [Example]

[0052] The present invention will be described in detail below with reference to examples and comparative examples.

[0053] [Examples 1 to 11, Comparative Examples 1 to 8] <Synthesis Example 1: Example Compound A-1> 100 g of isopropylidene glycol and 0.5 g of potassium tert-butoxide as a catalyst were charged into an autoclave, and the air in the autoclave was replaced with dry nitrogen. The catalyst was then dissolved at 130°C with stirring. Subsequently, 866 g of ethylene oxide was added dropwise using a dropping device at 130°C and 0.2 to 0.5 MPa (gauge pressure), and the mixture was stirred for 1 hour. The reaction mixture was then removed from the autoclave, adjusted to pH 3 with hydrochloric acid, and deacetalized. The mixture was then neutralized with potassium hydroxide and treated at 100°C under reduced pressure of -0.095 MPa (gauge pressure) for 3 hours to remove the water content, followed by filtration to obtain Example Compound A-1.

[0054] <Synthesis Examples 2 to 4: Example Compound A-2, Comparative Example Compounds A'-1 and A'-2> Example compound A-2 and comparative compounds A'-1 to A'-2 were obtained in the same manner as in Synthesis Example 1, except that the amounts of ethylene oxide, propylene oxide, and butylene oxide added were changed. However, in the case of a random adduct such as comparative compound A'-1, ethylene oxide and propylene oxide or butylene oxide were mixed in advance and the mixture was added dropwise using a dropping device to carry out the reaction. In addition, in the case of a block adduct such as example compound A-2, propylene oxide was added dropwise using a dropping device to achieve a predetermined number of moles of addition, and then ethylene oxide was added dropwise using a dropping device to achieve a predetermined number of moles of addition, to carry out the reaction.

[0055] The number-average molecular weights of the ethylene oxide and propylene oxide adducts were determined from the hydroxyl value obtained by hydroxyl value measurement in accordance with JIS K1557-1, and the values ​​of a and b in formula (1) were determined from the number-average molecular weights. Table 1 shows the total average number of moles of ethylene oxide and propylene oxide added for example compounds A-1 to A-2 and comparative example compounds A'-1 to A'-2. In Table 1, "AO" indicates the type of oxyalkylene group (AO) possessed by the alkylene oxide derivative shown in formula (1), and "PO" indicates an oxypropylene group. Table 1 also shows the monoether purity calculated by the above-mentioned method.

[0056] [Table 1]

[0057] [Evaluation method] Components (A) to (D), (A'), (D') and other components were prepared as water-in-oil sunscreen cosmetics in the compositions shown in Tables 2 and 3 (Examples), and Tables 4 and 5 (Comparative Examples). These cosmetics were evaluated according to the following criteria for (1) SPF improvement, (2) non-stickiness, (3) ease of spreading on dry skin, and (4) strength of the cosmetic film against rubbing.

[0058] (1) SPF improvement effect For each formulation, a blank without component (A) was prepared, and each sample was applied to a PMMA plate (HELIOPLATE HD6, manufactured by Labsphere) at 2 mg / cm 2 After application, the sample was left to stand in a dark place for 20 minutes, and the SPF was measured using an SPF analyzer (UV-2000S manufactured by Labsphere). Nine points on the plate were measured, and the average value was used to calculate the SPF. ブランク Similarly, each composition of the Examples and Comparative Examples was also obtained with [SPF 試料 The rate of change in SPF relative to the blank was calculated using the following formula:

[0059] SPF change rate relative to blank = [SPF 試料 ] / [SPF ブランク ] x 100

[0060] The rate of change in SPF relative to the blank was evaluated according to the following criteria, and a sunscreen cosmetic composition with an SPF-improving effect was determined to be 125% or higher.

[0061] <Evaluation criteria> ◎: Change rate is 150% or more ○: Change rate is 125% or more, but less than 150% △: Change rate is 110% or more but less than 125% ×: Rate of change is less than 110%

[0062] (2) Non-stickiness Twenty women (aged 23-55) were used as panelists, and after applying sunscreen cosmetics to the entire face, hands, arms, and legs, they were asked to rate the stickiness of the cosmetics according to the following evaluation criteria. The scores of the 20 panelists were calculated as a total, and sunscreen cosmetics with a total score of 20 or more were judged to be less sticky.

[0063] <Evaluation criteria> 2 points: No stickiness was felt. 1 point: Slight stickiness was felt. 0 points: It felt sticky.

[0064] ◎: Total score is 30 points or more ○: Total score is 20 or more but less than 30 points △: Total score is 10 or more but less than 20 points ×: Total points are less than 10 points

[0065] (3) Ease of application to dry skin Twenty women (aged 23-55) were used as panelists, who applied ethanol to their entire hands, arms, and legs, then waited for 20 minutes in a room with a constant humidity level. After that, the ease of spreading the sunscreen cosmetics when applying them was scored according to the following evaluation criteria. The scores of the 20 panelists were calculated, and sunscreen cosmetics with a total score of 20 or more were judged to be easy to spread even on dry skin.

[0066] <Evaluation criteria> 2 points: I was able to spread it on my dry skin without feeling any sticking. 1 point: When spreading on dry skin, I felt a slight stickiness, but was able to spread it. 0 points: When spreading on dry skin, it felt like it was catching and was difficult to spread.

[0067] ◎: Total score is 30 points or more ○: Total score is 20 or more but less than 30 points △: Total score is 10 or more but less than 20 points ×: Total points are less than 10 points

[0068] (4) Strength of the makeup film against rubbing Each sunscreen cosmetic was applied to a PMMA plate (HELIOPLATE HD6 manufactured by Labsphere) at 2 mg / cm 2 After application, the product was left to stand in the dark for 20 minutes, and the SPF was measured using an SPF analyzer (UV-2000S, manufactured by Labsphere). An 85g weight was then placed on the same plate so that it sandwiched a paper wiper (Kimwipe S-200, manufactured by Nippon Paper Crecia Co., Ltd.), and the weight and paper wiper were rubbed across the plate, and the SPF was measured in the same way. The rate of change in SPF before and after rubbing with the paper wiper was calculated using the following formula. A rate of change of less than 20% was determined to be a sunscreen cosmetic that could form a cosmetic film that was resistant to rubbing.

[0069] SPF change rate due to rubbing (%) = {([SPF before rubbing] - [SPF after rubbing]) / [SPF before rubbing]} x 100

[0070] ◎: Change rate is 0% or more but less than 10% ○: Change rate is 10% or more but less than 20% △: Change rate is 20% or more but less than 30% ×: Change rate is 30% or more and 100% or less

[0071] The compositions and evaluation results of Examples 1 to 11 and Comparative Examples 1 to 8 are shown in Tables 2 to 5. The compositions listed in Tables 2 to 5 indicate the ratio (parts by mass) of each component when the total mass is taken as 100 parts by mass. "C+D" indicates the total amount of component (C), component (D), and component (D'), and "C / (C+D)" indicates the ratio of component (C) to the total amount. Table 6 shows the compositions of components common to sunscreen cosmetics. The compositions listed in Table 6 indicate the ratio (parts by mass) of each component when the total mass of the compositions listed in Tables 2 to 5 is taken as 100 parts by mass.

[0072] The ingredients used in the sunscreen cosmetics are as follows: Titanium dioxide: Fatty acid-treated titanium dioxide fine particles ("MT-10EX" manufactured by Teika Corporation, average primary particle diameter 10 nm) Zinc oxide: Silicone-treated zinc oxide fine particles (Teikai Co., Ltd. "MZY-505M", average primary particle diameter 25 nm) PEG-9 polydimethylsiloxyethyl dimethicone: Shin-Etsu Chemical Co., Ltd. "KF-6028", HLB 4.0)

[0073] Furthermore, isopropyl myristylates, diisopropyl sebacate, ethylhexyl hydroxystearate, and isononyl isononanoate used as component (C) are all ester oils that are liquid at 25°C.

[0074] [Table 2]

[0075] [Table 3]

[0076] [Table 4]

[0077] [Table 5]

[0078] [Table 6]

[0079] All of the samples in Examples 1 to 11 had sufficient SPF-enhancing effects, were non-sticky, could be spread over the entire body even on dry skin, and formed a cosmetic film that was resistant to rubbing.

[0080] On the other hand, in Comparative Examples 1 to 8, sufficient effects were not obtained.

[0081] That is, in Comparative Example 1, because component (A) was not included, there was no SPF improvement effect, the resistance to rubbing was not significantly improved, and the ease of spread on dry skin was insufficient. In Comparative Examples 2 and 3, because an alkylene oxide derivative different from component (A) was blended, the SPF improvement effect, the ease of spread on dry skin, and the non-stickiness were insufficient, and the resistance to rubbing was not significantly improved. In Comparative Example 4, because component (C) was not included, the ease of spread on dry skin and the resistance to rubbing were insufficient. In Comparative Example 5, because component (D) was not included, the ease of spread on dry skin was particularly insufficient, and the resistance to rubbing was not significantly improved. In Comparative Example 6, the amount of component (A) was excessive, and the non-stickiness and ease of spread on dry skin were insufficient. In Comparative Example 7, the amount of component (B) was excessive, and the non-stickiness and ease of spread on dry skin were insufficient, and the resistance to rubbing was not significantly improved. In Comparative Example 8, a silicone oil different from component (D) was blended, and therefore the lack of stickiness, ease of spreading on dry skin, and resistance to rubbing were insufficient. [Industrial Applicability]

[0082] The medium-oil sunscreen cosmetic of the present invention can be applied to the skin, such as the face or skin, and exhibits unique effects not available with conventional sunscreen cosmetics, specifically, ease of spread on dry skin, non-stickiness, and resistance to rubbing of the cosmetic film, and is therefore expected to be widely applicable to sunscreen cosmetics.

Claims

[Claim 1] A water-in-oil sunscreen cosmetic comprising 0.5 to 10 mass% of the following component (A), 5 to 35 mass% of component (B), 1 to 30 mass% of component (C), and 5 to 35 mass% of component (D): (A) An alkylene oxide derivative represented by the following formula (1): 【Chemistry 1】 (In formula (1), AO represents an oxyalkylene group having 3 to 4 carbon atoms, EO represents an oxyethylene group, a represents the number of moles of the oxyalkylene group having 3 to 4 carbon atoms added, b represents the number of moles of the oxyethylene group added, a represents a number from 0 to 50, b represents a number from 1 to 50, a+b≧10, and 0≦a / b≦2. When the alkylene oxide derivative represented by formula (1) has both the oxyalkylene group having 3 to 4 carbon atoms and the oxyethylene group, the oxyalkylene group having 3 to 4 carbon atoms and the oxyethylene group are added in a random or block manner, and in the case of block addition, the order of arrangement does not matter.) (B) UV scattering agent (C) Ester oil that is liquid at 25°C (D) A kinematic viscosity at 25°C of 1 to 20 mm ２ / s linear silicone oil

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