Oil-in-water emulsion cosmetics for skin care using electrophoresis

Abstract

Provided is an oil-in-water type emulsion cosmetic for skin care that can uniformly apply an oil to the keratinous layer using electrophoresis.　The oil-in-water type emulsion cosmetic of the present disclosure comprises a dispersion medium including water and oil drops dispersed in the dispersion medium, said oil drops containing an ionic surfactant and an oil, and is to be used for skin care using electrophoresis.

Description

[Technical Field]

[0001] The present disclosure relates to an oil-in-water emulsion cosmetic for skin care using electrophoresis. [Background technology]

[0002] In recent years, a cosmetic method has been developed that involves placing electrodes on the skin and passing a weak electric current (waveform) to improve the skin.

[0003] Patent Document 1 discloses a cosmetic method for whitening or preventing or improving rough skin, which involves contacting the skin with a composition having a pH of 3.5 to 6.5, which contains 1 to 3% by mass of tranexamic acid and citric acid and / or hydrochloric acid, and in which the salt content in the composition is 0.5% by mass or less, and then subjecting the skin to iontophoresis from the positive electrode side.

[0004] Patent Document 2 discloses a beauty treatment device that includes an electrode unit having a first electrode with a circular outer periphery and a second electrode with a ring shape that is concentric with the first electrode and positioned outside the outer periphery of the first electrode, a first power supply unit that applies a first voltage that exhibits high frequency between the first and second electrodes, a measurement unit that measures the resistance value between the first and second electrodes, and a control unit that controls the first voltage in accordance with the measured resistance value.

[0005] Patent Document 3 discloses a beauty device that includes a skin stimulator including a stimulating surface that contacts the skin surface to impart stimulation, a skin stimulation source that imparts physical beauty stimulation to the skin stimulator, and a skin abnormality detection unit that optically detects abnormalities on the skin surface, where the skin abnormality detection unit includes a measurement unit that faces the measured portion on the skin surface, and where the measurement unit is positioned inside the outline of the stimulation surface when viewed from the front facing the stimulation surface.

[0006] Patent Document 4 discloses a beauty system including a beauty device having at least a gripping portion to be gripped by a user and a head portion that is integrally arranged with the gripping portion and is in a predetermined beauty operating state, and that can impart a predetermined beauty effect to the user's skin from the head portion; and a display terminal that displays guidance information related to how to use the beauty device so that the user can see it. The display terminal acquires environmental information and changes the display content of the guidance information according to the situation after a predetermined time, taking into consideration the current environmental conditions and / or weather forecasts. The guidance information displayed on the display terminal includes information indicating the specific position of the skin to which the head portion of the beauty device is to be brought into proximity or contact and / or the direction in which the head portion is to be pointed. The display terminal acquires position information of the location to which the user actually moved the head portion immediately before and / or information on the direction in which the head portion is actually pointed, and reflects this information to display guidance information that newly indicates the specific position of the skin to which the head portion of the beauty device is to be brought into proximity or contact and / or the direction in which the head portion is to be pointed.

[0007] Patent Document 5 discloses a beauty roller that rotates a rotating body by contacting it with the skin surface and applies high-frequency current to perform beauty treatment, and that includes a roughly rod-shaped main body portion that has a support portion near the end that supports the rotation shafts of at least two rotating bodies and is formed so that the outer periphery in the longitudinal direction can be grasped, two rotation shafts of the rotating body that protrude in different directions at a predetermined opening angle from the longitudinal direction of the main body portion, at least two rotating bodies that are rotatable by each rotation shaft and have electrode portions that apply high-frequency current to at least one portion that contacts the skin surface, and high-frequency generating means that is electrically connected to the electrode portions and generates high-frequency current.

[0008] Patent Document 6 discloses a sheet electrode for performing treatment via a mask covering a predetermined area of ​​the face, the sheet electrode having an adhesive member that allows the sheet electrode to be attached and detached to the mask, and an electrode that supplies a treatment signal to the area of ​​the predetermined area of ​​the face to be treated, the electrode being configured in a shape that corresponds to the height difference of the uneven shape of the area of ​​the face to be treated and the curved surface of the area, the adhesive member being provided on a part or end of the edge of the electrode configured in the shape, the electrode having a shape that includes a plurality of circles and a connecting portion that connects the plurality of circles, the plurality of circles being provided at positions that become the ends of the area to be treated, and the connecting portion having a shape that connects each of the plurality of circles provided at the ends. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 4860940 [Patent Document 2] Japanese Patent Application Publication No. 2019-055052 [Patent Document 3] International Publication No. 2017 / 150381 [Patent Document 4] Patent No. 6445105 [Patent Document 5] Japanese Patent Application Laid-Open No. 2017-124124 [Patent Document 6] Patent No. 5755623 Summary of the Invention [Problem to be solved by the invention]

[0010] The cosmetic methods and devices described in Patent Documents 1 and 2, which apply electrodes to the skin and pass a weak current (waveform) to achieve skin improvement effects, generally aim to promote transdermal delivery of water-soluble ionic ingredients that do not easily penetrate the skin to the depths of the stratum corneum using the current (waveform), but are not technologies for uniformly applying ionic ingredients to the stratum corneum. Furthermore, they cannot be used with oil, as oil is a dielectric and inhibits the current (waveform).

[0011] In addition, when moisture evaporates from the skin and the skin loses moisture, skin troubles such as rough skin and wrinkles tend to occur. In order to improve such skin troubles, various oils or the like are generally applied to the skin to suppress moisture evaporation from the skin and maintain moisture. In addition, in order to suppress moisture evaporation from the skin, it is important to form a uniform oil film with little unevenness on the stratum corneum. However, since oils or the like are generally transparent, it is difficult to check the state of the formed oil film, and the application performance of oils varies depending on the condition of the skin, so it has been difficult to apply oils uniformly and without unevenness to the stratum corneum.

[0012] Therefore, a subject of the present disclosure is to provide an oil-in-water emulsion cosmetic for skin care that is capable of applying oil uniformly to the stratum corneum using electrophoresis. [Means for solving the problem]

[0013] <Aspect 1> a dispersion medium comprising water, and Oil droplets dispersed in the dispersion medium Including, The oil droplets contain an ionic surfactant and an oil. An oil-in-water emulsion cosmetic for skin care using electrophoresis. <Aspect 2> A cosmetic preparation according to aspect 1, wherein the oil droplets further contain a nonionic surfactant. <Aspect 3> Aspect 3. The cosmetic preparation according to aspect 2, wherein the molar ratio of the ionic surfactant to the nonionic surfactant is 90:10 to 10:90. <Aspect 4> A cosmetic preparation according to any one of Aspects 1 to 3, wherein the ionic surfactant is an anionic surfactant. <Aspect 5> A cosmetic preparation according to any one of Aspects 1 to 4, wherein the oil component comprises a water-containing oil. <Aspect 6> A cosmetic preparation according to any one of Aspects 1 to 5, wherein the oil droplets have an average particle size of 200 nm or less. <Aspect 7> A cosmetic preparation according to any one of Aspects 1 to 6, which is used by being impregnated into a porous substrate. <Aspect 8> A porous substrate impregnated with the cosmetic preparation according to any one of aspects 1 to 7, and It takes the form of a face mask, A cosmetic-impregnated sheet for skin care using electrophoresis. <Aspect 9> A device capable of generating an electric field between the cosmetic composition according to any one of aspects 1 to 7 or the sheet according to aspect 8 is applied to the skin, and the device is then applied to the area where the cosmetic composition or the sheet is applied, thereby moving oil droplets contained in the cosmetic composition or the sheet to the stratum corneum side of the skin. Beauty method. <Aspect 10> A cosmetic method according to aspect 9, wherein the skin is facial skin and the application of the device is performed based on at least one piece of information selected from medical history information, environmental information, and skin information. <Aspect 11> The cosmetic method according to aspect 9 or 10, wherein the method of application of the device is determined based on the application time. <Aspect 12> 12. The cosmetic method according to aspect 10 or 11, wherein the skin information is at least one selected from shape, color, moisture content, sebum content, temperature, feel on use, pH, resident bacteria, reflected light, nutrients, blood flow, and elasticity. <Aspect 13> A means for presenting an application method of the device in the cosmetic method according to any one of aspects 9 to 12 to a user as an image; and a means for allowing the user to freely change the application method of the device according to the user's preferences; Equipped with Information output system. <Aspect 14> 14. The information output system according to claim 13, further comprising means for recording information on the application method of the device and transferring the information to a recording medium. <Aspect 15> a step of presenting an application method of the device in the cosmetic method according to any one of aspects 9 to 12 to a user as an image; and A procedure for optionally changing the application method of the device according to the user's preferences; Execute Information output program. <Aspect 16> 16. The information output program according to claim 15, further comprising a procedure for recording information on the application method of the device and transferring the information to a recording medium. [Effects of the Invention]

[0014] According to the present disclosure, it is possible to provide an oil-in-water emulsion cosmetic for skin care that can apply oil uniformly to the stratum corneum using electrophoresis. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram illustrating the movement of oil droplets in the oil-in-water emulsion cosmetic of the present disclosure to the stratum corneum by electrophoresis. [Figure 2] 1 is a photograph showing the state of oil droplets in an oil-in-water emulsion cosmetic of the present disclosure before and after electric current irradiation. [Figure 3] 1 is a graph showing the amount of oil penetration into the skin based on differences in the application conditions or average particle size of the oil droplets of the oil-in-water emulsion cosmetic of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present invention.

[0017] The oil-in-water emulsion cosmetic of the present disclosure (sometimes simply referred to as "cosmetic") comprises a dispersion medium containing water and oil droplets dispersed in this dispersion medium, and the oil droplets comprise an ionic surfactant and an oil component.

[0018] Without being limited by the theory, the principle of action by which the oil-in-water emulsion cosmetic of the present disclosure can care for the skin by uniformly applying oil to the stratum corneum using electrophoresis is believed to be as follows.

[0019] Unlike ionic components, oils do not exhibit ionic properties themselves, and therefore do not undergo electrophoresis in cosmetics even when an electric field is applied. In the oil-in-water emulsion cosmetic of the present disclosure, oil droplets are prepared using an ionic surfactant together with the oil, and therefore, as shown in FIG. 1, a negative charge due to the ionic surfactant is formed around oil droplets 3 containing oil dispersed in water 2. As a result, oil droplets 2 containing oil exhibit ionic properties, and the oil droplets 2 can be moved toward the stratum corneum 1 of the skin by applying an electric field using an electric field generator 4. Note that the charge due to the ionic surfactant may be a positive charge. In this case, the voltage applied to the electric field generator 4 may be set to a positive value, opposite to that shown in FIG. 1, so that the stratum corneum side is negatively charged.

[0020] Oil-in-water emulsion cosmetics generally have a higher proportion of water phase than oil phase. Therefore, even if such cosmetics are simply applied to the area of ​​the skin that requires care, the oil will not be highly coated on the skin until the water completely evaporates, and the cosmetic will move around on the skin to which it has been applied until the water evaporates, making it difficult to apply a high concentration of oil to the skin uniformly using oil-in-water emulsion cosmetics.

[0021] Furthermore, because oil droplets in oil-in-water emulsion cosmetics tend to collect on rough skin protrusions due to differences in surface tension, even if the moisture in the applied cosmetics can be successfully evaporated, it is thought that it will be difficult to form a uniform oil film on the stratum corneum because the oil adhesion ratio differs between the skin's ridges and sulci.

[0022] On the other hand, the cosmetic preparation of the present disclosure, when subjected to an electric field, can force oil droplets containing oil to reach the skin surface relatively quickly and form a substantially flat, high-concentration oil layer, as shown in Figure 2. Furthermore, because oil generally has good compatibility with skin, it is believed that the high-concentration oil that has migrated to the skin side will uniformly coat the stratum corneum even before water evaporation.

[0023] Furthermore, for example, when oil is simply applied to dry, rough skin to form an oil film, the oil film merely prevents moisture from evaporating from the inside. On the other hand, the cosmetic preparation of the present disclosure also contains a large amount of water, and this water first replenishes moisture in the dry skin. Then, the oil that has migrated to the stratum corneum by electrophoresis can coat the moistened stratum corneum with a uniform oil film, thereby exerting a favorable emollient effect. Therefore, it is believed that skin care can be carried out more effectively than when oil is simply applied.

[0024] The iontophoresis (ion introduction) technology described in Patent Documents 1 and 2 is a technology for promoting transdermal delivery of water-soluble ionic components that are difficult to penetrate the skin by applying electrodes to the skin and passing a weak current through the electrodes, but is not a technology for forming an effective coating of ionic components on the stratum corneum.

[0025] <Oil-in-water emulsion cosmetics> The oil-in-water emulsion cosmetic of the present disclosure can be used for skin care using electrophoresis, and comprises a dispersion medium containing water and oil droplets dispersed in the dispersion medium, and these oil droplets contain an ionic surfactant and an oil component.

[0026] <Dispersion medium> (water) The water that can be used in the oil-in-water emulsion cosmetic of the present disclosure is not particularly limited, but can be water used in cosmetics, quasi-drugs, etc. For example, ion-exchanged water, distilled water, ultrapure water, tap water, etc. can be used.

[0027] The amount of water to be added is not particularly limited, but from the viewpoint of emulsion stability, mobility of emulsified particles, etc., it can be, for example, 50% by mass or more, 60% by mass or more, 65% by mass or more, or 70% by mass or more of the total amount of the cosmetic, and can be 95% by mass or less, 90% by mass or less, 85% by mass or less, or 80% by mass or less.

[0028] <Oil drop> The oil droplets (emulsified particles) serving as the oil phase or dispersed phase in the oil-in-water emulsion cosmetic of the present disclosure contain at least an ionic surfactant and an oil component, and can optionally further contain at least one selected from a nonionic surfactant and a higher alcohol.

[0029] When the oil droplets further contain at least one selected from a nonionic surfactant and a higher alcohol in addition to the ionic surfactant and oil, the ionic surfactant and the nonionic surfactant and / or the higher alcohol can form a solid or gel-like interfacial membrane around the oil droplets. Such an interfacial membrane can be confirmed, for example, by dialysis, ultracentrifugation, or the like.

[0030] The average particle size of the oil droplets is not particularly limited, and can be, for example, 10 μm or less, 1 μm or less, 500 nm or less, 300 nm or less, 200 nm or less, 150 nm or less, 100 nm or less, 90 nm or less, or 80 nm or less. The lower limit of the average particle size is not particularly limited, and can be, for example, 5 nm or more, 10 nm or more, 20 nm or more, 30 nm or more, or 50 nm or more. The average particle size of the oil droplets can be defined as the average value of the diameters of the oil droplets optically measured by dynamic light scattering or the like, assuming that the particle shape of the oil droplets is spherical.

[0031] When the average particle size of the oil droplets is 200 nm or less, at least a portion of the oil droplets present in the cosmetic can penetrate into the skin through the stratum corneum or pores of the skin, thereby further improving the skin-improving effects such as moisturizing. In particular, oil droplets having the above-mentioned interfacial film are less likely to break than general emulsified particles that do not have such an interfacial film, even when subjected to actions such as increased density of oil droplets that have migrated to the skin side or pressure from the electrodes of an electric field generator, and are therefore advantageous in terms of skin-improving effects.

[0032] The melting initiation temperature of the oil droplets is not particularly limited, and from the viewpoint of reducing or suppressing stickiness, it can be, for example, 25° C. or higher, 27° C. or higher, or 30° C. or higher, and can be 50° C. or lower, 45° C. or lower, or 40° C. or lower. Here, the melting initiation temperature refers to the temperature at the intersection of a straight line extending the low-temperature baseline to a high-temperature side and a tangent drawn at the point where the gradient of the curve on the low-temperature side of the melting peak is maximum, as measured by differential scanning calorimetry (DSC) (manufactured by TA Instruments) in accordance with JIS K7121.

[0033] (ionic surfactants) The content of the ionic surfactant in the oil-in-water emulsion cosmetic of the present disclosure is not particularly limited, and can be, for example, 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, or 0.4% by mass or more relative to the total amount of the cosmetic, and can be 5.0% by mass or less, 4.0% by mass or less, 3.0% by mass or less, 2.0% by mass or less, or 1.0% by mass or less.

[0034] The ionic surfactant is not particularly limited, and anionic surfactants, cationic surfactants (e.g., alkyltrimethylammonium salts), or amphoteric surfactants (e.g., imidazoline-based amphoteric surfactants) can be used. These can be used alone or in combination. Among these, it is preferable to use anionic surfactants from the viewpoints of emulsion stability, electrophoresis, low irritation to the skin, etc.

[0035] The anionic surfactant is not particularly limited, and for example, at least one selected from carboxylate, sulfonate, sulfate, and phosphate salt types can be used. Among these, sulfonate salt types are preferred from the viewpoint of electrophoresis, etc. The salt form is not particularly limited, and examples include alkali metal salts such as sodium salt, potassium salt, and lithium salt, alkaline earth metal salts such as magnesium salt and calcium salt, ammonium salt, and amino acid salt.

[0036] As the sulfonate-type anionic surfactant, for example, N-acylmethyl taurine salts can be used, and for example, stearoyl methyl taurine salts, lauroyl methyl taurine salts, myristoyl methyl taurine salts, coconut oil fatty acid methyl taurine salts, etc. can be suitably used.

[0037] (oil content) There are no particular limitations on the content of oil in the oil-in-water emulsion cosmetic of the present disclosure, and it can be, for example, 0.5% by mass or more, 1% by mass or more, 3% by mass or more, 5% by mass or more, 7% by mass or more, 10% by mass or more, 13% by mass or more, or 15% by mass or more relative to the total amount of the cosmetic, and can also be 50% by mass or less, 40% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less.

[0038] The oil is not particularly limited, and examples thereof include liquid oils, solid oils, waxes, hydrocarbon oils, synthetic ester oils, silicone oils, and water-holding oils. These can be used alone or in combination. Among these, water-holding oils are preferred because they replenish moisture in the skin, prevent moisture loss from the skin, keep the skin moist, and easily exert an emollient effect that softens the skin. Here, water-holding oil refers to oils with a water holding rate of 50% or more, calculated by carrying out the following water holding test using Equation 1: Water holding test The initial amount of sample (oil component) to be measured for water holding rate is weighed and heated to 70°C, after which water heated to 70°C is gradually added to the sample while stirring. The end point is when water begins to float to the surface of the sample, and the amount of water added up to that point is measured. Water holding rate (%) = [(amount of water added (g) + initial amount of sample (g)) / initial amount of sample (g)] × 100 ... Equation 1

[0039] Examples of liquid oils and fats include avocado oil, camellia oil, evening primrose oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, persic oil, wheat germ oil, camellia oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, tea seed oil, Japanese kaya oil, rice bran oil, Chinese tung oil, Japanese tung oil, jojoba oil, germ oil, triglycerin, glycerin trioctanoate, and glycerin triisopalmitate.

[0040] Examples of solid fats and oils include cacao butter, coconut oil, horse fat, hardened coconut oil, palm oil, beef tallow, mutton tallow, hardened beef tallow, palm kernel oil, lard, beef bone fat, Japan wax kernel oil, hardened oil, beef trotter fat, Japan wax, and hardened castor oil.

[0041] Examples of waxes include beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, Ibota wax, whale wax, montan wax, rice bran wax, lanolin, kapok wax, lanolin acetate, liquid lanolin, sugarcane wax, lanolin fatty acid isopropyl, hexyl laurate, reduced lanolin, jojoba wax, hard lanolin, shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, lanolin fatty acid polyethylene glycol, and POE hydrogenated lanolin alcohol ether.

[0042] Examples of hydrocarbon oils include liquid paraffin, ozokerite, squalane, pristane, paraffin, ceresin, squalene, petrolatum, microcrystalline wax, olefin oligomer, isododecane, and isohexadecane.

[0043] Examples of synthetic ester oils include isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, cholesteryl 12-hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid esters, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentaerythritol tetra-2-ethylhexanoate, tri-2-ethylhexanoate, Glyceryl hexanoate, glyceryl trioctanoate, glyceryl triisopalmitate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glyceryl trimyristate, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, acetoglyceride, 2-heptylundecyl palmitate, diisostearate, diisostearate, methyl acrylate / methyl acrylate copolymer ... Isobutyl, N-lauroyl-L-glutamic acid-2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, triethyl citrate, ethyl acetate, butyl acetate, amyl acetate, crotamiton (C 13 H 17 NO) etc.

[0044] Examples of silicone oils include methylphenyl silicones such as dimethylpolysiloxane (dimethicone), methylhydrogenpolysiloxane, methylphenylpolysiloxane, trimethylpentaphenyltrisiloxane, diphenyldimethicone, diphenylsiloxyphenyltrimethicone, phenyltrimethicone, and phenyldimethicone; perfluorooctylethyl / diphenyldimethicone, decamethylpolysiloxane, dodecamethylpolysiloxane, tetramethyltetrahydrogenpolysiloxane, silicone resins that form a three-dimensional network structure, and silicone rubber.

[0045] Examples of water-containing oils include the Eldew (trademark) series manufactured by Ajinomoto Co., Inc., such as N-lauroyl-L-glutamic acid di(phytosteryl 2-octyldodecyl) (Eldew (trademark) PS-203, water holding rate 170%), N-lauroyl-L-glutamic acid di(cholesteryl behenyl octyldodecyl) (Eldew (trademark) CL-301, water holding rate 120%), N-lauroyl-L-glutamic acid di(cholesteryl octyldodecyl) (Eldew (trademark) CL-202, water holding rate 130%), N-lauroyl-L-glutamic acid di(phytosteryl 2-octyldodecyl) (Eldew (trademark) CL-203, water holding rate 170%), N-lauroyl-L-glutamic acid di(cholesteryl octyldodecyl) (Eldew (trademark) CL-202, water holding rate 130%), N-lauroyl-L-glutamic acid di(phytosteryl 2-octyldodecyl) (Eldew (trademark) CL-202, water holding rate 130%), and N-lauroyl-L-glutamic acid di(phytosteryl 2-octyldodecyl) (Eldew (trademark) PS-203, water holding rate 170%). Examples of water-containing oils include N-lauroyl-L-glutamic acid diesters such as N-lauroyl-L-glutamic acid di(phytosteryl behenyl 2-octyldodecyl) (Eldew™ PS-304, water-holding rate 125%) and N-lauroyl-L-glutamic acid di(phytosteryl behenyl 2-octyldodecyl) (Eldew™ PS-306, water-holding rate 135%), N-lauroyl sarcosine isopropyl (Eldew™ SL-205, water-holding rate 115%), and N-myristoyl-N-methyl-β-alanine (phytosteryl decyltetradecyl) (Eldew™ APS-307, water-holding rate 165%). These water-containing oils have properties similar to the intercellular lipid components that make up the stratum corneum, so they blend well with the moisture in the stratum corneum and can maintain high moisturizing properties for a long period of time. Among these, N-lauroyl-L-glutamic acid diester is preferred, and N-lauroyl-L-glutamic acid di(phytosteryl 2-octyldodecyl) is more preferred.

[0046] Other examples of water-holding oils include bis-diglyceryl polyacyladipate-2 (Softisun™ 649, manufactured by Sasol, water holding rate: 170%), tetrapentaerythritol tetra(behenate / benzoate / ethylhexanoate) (water holding rate: 50%), phytosteryl macadamiate (YOFCO-MAS, manufactured by Nippon Fine Chemicals Mfg. Co., Ltd., water holding rate: 250%), and bis(phytosteryl / behenyl / isostearyl) dimer dilinoleyl dimer dilinoleate (PLANDOOL-G, manufactured by Nippon Fine Chemicals Mfg. Co., Ltd., water holding rate: 200%). Among these, from the viewpoint of emollient properties, diesters of diglycerin and fatty acids and / or dicarboxylic acids (diglycerin diesters) are preferred, and bis-diglyceryl polyacyladipate-2 is more preferred.

[0047] <Optional ingredients> The oil-in-water emulsion cosmetic of the present disclosure may be appropriately blended with various other components depending on the intended use, etc., as long as the effects of the present disclosure are not affected. Examples of the various components include additives that are typically blended into cosmetics, such as nonionic surfactants; water-soluble alcohols; higher alcohols; hydrophilic or hydrophobic powders such as talc; moisturizers; water-soluble polymers (natural, semi-synthetic, synthetic, inorganic); coating agents such as anionic coating agents, cationic coating agents, and nonionic coating agents; ultraviolet absorbers such as benzoic acid-based ultraviolet absorbers; sequestering agents such as 1-hydroxyethane-1,1-diphosphonic acid; amino acids such as neutral amino acids and basic amino acids, and salts or derivatives thereof; monoethanolamine, etc. Examples of optional ingredients include organic amines, polymer emulsions such as acrylic resin emulsions, silicone elastomers such as dimethicone crosspolymers, chelating agents, pH adjusters such as lactic acid-sodium lactate, skin nutrients, vitamins such as vitamin A, vitamin C, and their derivatives, antioxidants such as tocopherols, antioxidant aids such as phosphoric acid, preservatives such as ethylparaben, organic acids such as alkoxysalicylic acids that have a carboxyl group and ionize to generate hydrogen ions, or their salts or derivatives, thickeners, dyes, pigments, fragrances, extracts, and pharmaceuticals. These may be used alone or in combination. Depending on their properties, various ingredients may be incorporated into the aqueous phase as a continuous phase and / or the oil phase as a dispersed phase, i.e., within the oil droplets. Some of these optional ingredients are described in detail below.

[0048] Examples of water-soluble alcohols include lower alcohols such as ethanol, propanol, butanol, pentanol, and hexanol, polyhydric alcohols such as ethylene glycol, polyhydric alcohol polymers such as diethylene glycol, dihydric alcohol alkyl ethers such as ethylene glycol monomethyl ether, dihydric alcohol alkyl ethers such as diethylene glycol monomethyl ether, dihydric alcohol ether esters such as ethylene glycol monomethyl ether acetate, glycerin monoalkyl ethers such as xyl alcohol, sugar alcohols such as sorbitol, monosaccharides such as D-glyceryl aldehyde, oligosaccharides such as sucrose, polysaccharides such as cellulose, and derivatives thereof. These may be used alone or in combination.

[0049] Examples of moisturizing agents include glycerin, diethylene glycol, butylene glycol, polyethylene glycol, hexylene glycol, xylitol, sorbitol, maltitol, chondroitin sulfate, hyaluronic acid, mucoitin sulfate, caronic acid, atelocollagen, elastin, amino acids, nucleic acids, cholesteryl-12-hydroxystearate, sodium lactate, bile salts, dl-pyrrolidone carboxylate, short-chain soluble collagen, diglycerin (EO)PO adduct, Rosa serrata extract, Botrytis extract, Melilot extract, etc. These may be used alone or in combination.

[0050] Examples of natural water-soluble polymers include plant-derived water-soluble polymers such as gum arabic, tragacanth gum, galactan, guar gum, locust bean gum, tamarind gum, carob gum, karaya gum, carrageenan, pectin, agar, quince seed (quince), algae colloid (cassow extract), starch (rice, corn, potato, wheat), and glycyrrhizic acid; microbial-derived water-soluble polymers such as xanthan gum, dextran, succinoglycan, and pullulan; and animal-derived water-soluble polymers such as collagen, casein, albumin, and gelatin. These may be used alone or in combination.

[0051] Examples of semi-synthetic water-soluble polymers include starch-based water-soluble polymers such as carboxymethyl starch and methylhydroxypropyl starch; cellulose-based water-soluble polymers such as methyl cellulose, nitrocellulose, ethyl cellulose, methylhydroxypropyl cellulose, hydroxyethyl cellulose, sodium cellulose sulfate, hydroxypropyl cellulose, carboxymethyl cellulose (CMC), crystalline cellulose, and cellulose powder; and alginic acid-based water-soluble polymers such as sodium alginate and propylene glycol alginate. These may be used alone or in combination.

[0052] Examples of synthetic water-soluble polymers include vinyl-based water-soluble polymers such as polyvinyl alcohol, polyvinyl methyl ether, polyvinylpyrrolidone, and carboxyvinyl polymer (Carbopol); polyoxyethylene-based water-soluble polymers such as polyethylene glycol 20,000, 4,000,000, and 600,000; copolymer-based water-soluble polymers such as polyoxyethylene-polyoxypropylene copolymers; acrylic-based water-soluble polymers such as sodium polyacrylate, polyethyl acrylate, and polyacrylamide, as well as polyethyleneimine and cationic polymers. These may be used alone or in combination.

[0053] Examples of extracts include tea extract, Rosa rugosa extract, Scutellaria root extract, Houttuynia cordata extract, Phellodendron bark extract, Coptis japonica extract, Cnidium rhizome extract, Ginger extract, Citrus peel extract, Angelica acutiloba extract, Melilot extract, Nettle leaf extract, Hypericum perforatum extract, Licorice extract, Peony extract, Soapwort extract, Choujuso extract, Enmeisou extract, Luffa extract, Birch extract, Cinchona extract, Sanguisorba officinalis extract, Saxifraga extract, Chamomile extract, Sophora flavescens extract, Splashback extract, Fennel extract, primrose extract, rose extract, rehmannia root extract, lemon extract, loquat extract, lithospermum root extract, aloe extract, calamus root extract, rhubarb extract, eucalyptus extract, ononis extract, horsetail extract, sage extract, thyme extract, safflower extract, camellia seed extract, camellia flower extract, cherry leaf extract, pine extract, okra extract, tangerine extract, ginseng extract, red clover flower extract, mallow extract, yarrow extract, seaweed extract, garlic extract , Cucumber extract, Clove extract, Raspberry extract, Melissa extract, Iris extract, Grape extract, Carrot extract, Ginseng extract, Horse chestnut extract, Peach extract, Peach leaf extract, Coix seed extract, Mulberry extract, Cornflower extract, Musk extract, Hamamelis extract, Ginkgo extract, Cinnamon bark extract, Cinnamon extract, Lily extract, Saffron extract, Pomegranate extract, Swertia japonica extract, Capsicum tincture extract, Cantharis extract, Placenta extract, Collagen extract Examples of extracts include ginseng, yeast extract, Bulgarian rose water, star fruit leaf extract, herb extract, neem leaf extract, comfrey extract, winter strawberry extract, yomena extract, Mube extract, Ryukyu strawberry extract, Indian yomena extract, Muteba extract, castanopsis extract, rosemary extract, apricot extract, gentian extract, peppermint extract, tallow extract, hop extract, kiwi extract, apple extract, hawthorn extract, turmeric extract, bayberry extract, and oak extract. These can be used alone or in combination.

[0054] Examples of the drug include whitening agents, activators, blood circulation promoters, anti-inflammatory agents, antioxidants, enzymes, vitamins, hormones, antibacterial agents, antiseborrheic agents, amino acids and derivatives thereof, sugar alcohols and derivatives thereof, fat-soluble drugs, drugs that have been made fat-soluble, and hair growth drugs. These can be used alone or in combination.

[0055] Examples of whitening agents include hydroquinone derivatives such as hydroquinone α-D-glucose, hydroquinone β-D-glucose (arbutin), hydroquinone α-L-glucose, hydroquinone β-L-glucose, hydroquinone α-D-galactose, hydroquinone β-D-galactose, hydroquinone α-L-galactose, and hydroquinone β-L-galactose; kojic acid and its salts or derivatives; L-ascorbic acid monophosphate, L-ascorbic acid 2-sulfate, and the like; L-ascorbic acid and its salts or derivatives thereof, such as ascorbic acid monoesters, L-ascorbic acid glucosides such as L-ascorbic acid 2-glucoside, or salts thereof; for example, tranexamic acid, tranexamic acid dimers (e.g., trans-4-(trans-aminomethylcyclohexanecarbonyl)aminomethylcyclohexanecarboxylic acid hydrochloride), esters of tranexamic acid and hydroquinone (e.g., trans-4-aminomethylcyclohexanecarboxylic acid 4'-hydroxyphenyl ester), thiazolinone, ... Examples of such an ester include tranexamic acid and gentisic acid (e.g., 2-(trans-4-aminomethylcyclohexylcarbonyloxy)-5-hydroxybenzoic acid and its salts), and tranexamic acid amides (e.g., trans-4-aminomethylcyclohexanecarboxylic acid methylamide and its salts, trans-4-(p-methoxybenzoyl)aminomethylcyclohexanecarboxylic acid and its salts, trans-4-guanidinomethylcyclohexanecarboxylic acid and its salts), as well as salts or derivatives thereof; ellagic acid and its salts or derivatives thereof; salicylic acid and its salts or derivatives thereof, such as salicylic acid, 3-methoxysalicylic acid and its salts, 4-methoxysalicylic acid and its salts, and 5-methoxysalicylic acid and its salts; resorcinol derivatives such as alkylresorcinols, such as phenylethylresorcinol, resorcinol, and 4-n-butylresorcinol, and salts thereof; niacin and its derivatives, such as nicotinamide; and nucleotides, such as adenosine and guanosine, or derivatives thereof.

[0056] Examples of the activator include royal jelly, photosensitizers, cholesterol derivatives, and the like.

[0057] Examples of blood circulation promoters include nonylic acid valenylamide; nicotinic acid benzyl ester; nicotinic acid β-butoxyethyl ester; capsaicin; zingerone; cantharides tincture; ichthammol; tannic acid; α-borneol; tocopherol nicotinate; inositol hexanicotinate; cyclandelate; cinnarizine; tolazoline; acetylcholine derivatives; verapamil; cepharanthine; γ-oryzanol; carbronium chloride, etc.

[0058] Examples of anti-inflammatory agents include tranexamic acid, thiotaurine, hypotaurine, glycyrrhizinic acid derivatives, glycyrrhetinic acid derivatives, salicylic acid derivatives, hinokitiol, zinc oxide, and allantoin.

[0059] Examples of antioxidants include thiotaurine, glutathione, catechin, albumin, ferritin, and metallothionein.

[0060] Examples of enzymes include trypsin, lysozyme chloride, chymotrypsin, semi-alkaline proteinase, serrapeptase, lipase, hyaluronidase, and the like.

[0061] Examples of vitamins include vitamin B6; vitamin B6 derivatives such as vitamin B6 hydrochloride; vitamin B2; vitamin B12; nicotinic acid; nicotinic acid derivatives such as nicotinamide; pantothenyl ethyl ether, and the like.

[0062] Examples of hormone agents include oxytocin, corticotropin, vasopressin, secretin, gastrin, calcitonin, and the like.

[0063] Examples of antibacterial agents include resorcinol, sulfur, salicylic acid, zinc pyrithione, photosensitizer No. 101, photosensitizer No. 102, orthovirox, and hinokitiol.

[0064] Examples of antiseborrheic agents include sulfur; thianthol, and the like.

[0065] Examples of amino acids and derivatives thereof include serine, methionine, tryptophan, glycine, trimethylglycine, glycylglycine, 1-piperidinepropionic acid, and the like.

[0066] Examples of sugar alcohols and derivatives thereof include erythritol, xylitol, mannitol, sorbitol, inositol, and the like.

[0067] Examples of fat-soluble drugs include retinol derivatives (vitamin A); tocopherol (vitamin E); and the like.

[0068] An example of a lipophilic drug is acetylated hyaluronic acid.

[0069] Examples of hair growth drugs include Swertia japonica extract; acetylcholine derivatives; cepharanthine; carpronium chloride; capsicum tincture; cantharis extract; nonylic acid vanillamide; pyridoxine or its derivatives; benzalkonium chloride; isopropylmethylphenol; zinc pyrithione; photosensitizers such as photosensitizer No. 101, photosensitizer No. 102, and photosensitizer No. 301; orthopirox; hinokitiol; placenta extract; biotin; serine; methionine; tryptophan; vitamin B2; vitamin B12; pantothenic acid or its derivatives; nucleotides such as adenosine and guanosine or their derivatives, etc.

[0070] Examples of inorganic water-soluble polymers include bentonite, AlMg silicate (veegum), laponite, hectorite, and silicic anhydride.

[0071] Among the optional components mentioned above, the use of higher alcohols is advantageous from the viewpoint of improving usability (for example, reducing stickiness).

[0072] In addition to improving usability, it is advantageous to use a nonionic surfactant in combination with a higher alcohol from the viewpoints of ease of formation of an interfacial film of oil droplets, emulsion stability, etc. These can contribute to the formation of a solid or gel-like interfacial film around the oil droplets, and the nonionic surfactant can exhibit an entropy repulsion effect near the interface of the oil droplets, thereby suppressing aggregation and coalescence of the oil droplets and further improving the emulsion stability of the oil-in-water emulsion cosmetic.

[0073] The amount of nonionic surfactant blended is not limited to the following, but from the perspective of, for example, emulsion stability associated with entropy repulsion and the migration speed of oil droplets associated with electrophoresis, it can be 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 0.7% by mass or more, 1.0% by mass or more, 1.5% by mass or more, 2.0% by mass or more, 2.5% by mass or more, 3.0% by mass or more, 3.5% by mass or more, or 4.0% by mass or more relative to the total amount of the cosmetic, and can be 10% by mass or less, 7.0% by mass or less, 5.0% by mass or less, 4.0% by mass or less, 3.0% by mass or less, 2.0% by mass or less, or 1.0% by mass or less.

[0074] The molar ratio of the ionic surfactant to the nonionic surfactant can be, for example, any of 90:10, 85:15, 80:20, 75:25, 70:30, 65:35, and 60:40, to any of 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, and 40:60. While the use of a nonionic surfactant can improve emulsion stability, it tends to reduce the migration speed of oil droplets associated with electrophoresis. Considering these balances, the range of 90:10 to 25:75 is preferred, the range of 85:15 to 30:70 is more preferred, the range of 80:20 to 35:65 is even more preferred, and the range of 75:25 to 40:60 is particularly preferred.

[0075] The nonionic surfactant is not particularly limited, but from the viewpoint of, for example, emulsion stability and ease of formation of an interfacial film of oil droplets, hydrophilic nonionic surfactants having an HLB of 12.0 or more, 12.5 or more, 13.0 or more, 13.5 or more, 14.0 or more, 14.5 or more, 15.0 or more, 15.5 or more, or 16.0 or more can be used. There is no particular restriction on the upper limit of the HLB of such nonionic surfactants, and it can be, for example, 20.0 or less, 19.5 or less, 19.0 or less, 18.5 or less, or 18.0 or less. Here, HLB generally indicates the affinity of a surfactant for water and oil, and is a parameter known as the hydrophilic-lipophilic balance, which can be easily determined by known calculation methods such as the Griffin method.

[0076] The nonionic surfactants can be used alone or in combination of two or more. For example, a first nonionic surfactant having the above-mentioned HLB can be used in combination with a second nonionic surfactant having a lower HLB. For example, when preparing an oil-in-water emulsion cosmetic by the microemulsion method described below, it is preferable to use a lipophilic nonionic surfactant with an HLB of 2.0 or more, 2.5 or more, or 3.0 or more, and 10.0 or less, 8.0 or less, or 6.0 or less as the second nonionic surfactant.

[0077] Specific examples of nonionic surfactants include polyoxyethylene alkyl ethers, glycerin alkyl ethers, polyglycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbit fatty acid esters, polyoxyethylene lanolin / lanolin alcohol / beeswax derivatives, polyoxyethylene castor oil / hydrogenated castor oil, hydrogenated castor oil derivatives, polyoxyethylene sterol / hydrogenated sterols, polyethylene glycol fatty acid esters, polyoxyethylene glyceryl isostearate, propylene glycol fatty acid esters, polyoxyethylene propylene glycol fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene polyoxypropylene alkyl ethers, tetrapolyoxyethylene tetrapolyoxypropylene ethylenediamine, alkanolamides, sucrose fatty acid esters, alkylethoxydimethylamine oxide, trioleyl phosphate, and polyether-modified silicones. Among these, polyoxyethylene alkyl ethers, polyglycerin fatty acid esters, and polyoxyethylene hydrogenated castor oil are preferred. These can be used alone or in combination. For example, when preparing an oil-in-water emulsion cosmetic by the microemulsion method described below, it is preferable to use a polyglycerol fatty acid ester and polyoxyethylene hydrogenated castor oil in combination.

[0078] Examples of polyoxyethylene alkyl ethers include polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene behenyl ether, and polyoxyethylene stearyl ether, and among these, polyoxyethylene behenyl ether and polyoxyethylene stearyl ether are preferred. Specifically, for example, POE (9) lauryl ether (HLB 14.5), POE (10) cetyl ether (HLB 13.5), POE (15) cetyl ether (HLB 15.5), POE (20) cetyl ether (HLB 17.0), POE (23) cetyl ether (HLB 18.0), POE (4) stearyl ether (HLB 9.0), POE (20) stearyl ether (HLB 18.0), POE (21) stearyl ether (HLB value 18.0), and POE (10) oleyl ether (HLB 18.0). Examples of polyoxyethylene alkyl ethers include POE(10) (HLB 14.5), POE(15) oleyl ether (HLB 16.0), POE(20) oleyl ether (HLB 17.0), POE(50) oleyl ether (HLB 18.0), POE(10) behenyl ether (HLB 10), POE(20) behenyl ether (HLB 16.5), POE(30) behenyl ether (HLB 18.0), and POE(10) (C12-15) alkyl ether (HLB 15.5), among which POE(30) behenyl ether is preferred. Examples of commercially available polyoxyethylene alkyl ethers include NIKKOL™ BB-30 (manufactured by Nikko Chemicals Co., Ltd.). Here, POE refers to a polyoxyethylene group, and the number in parentheses following POE refers to the average number of moles of polyoxyethylene groups added in the compound.

[0079] Examples of polyglycerin fatty acid esters include diglyceryl diisostearate (HLB 4.0), diglyceryl triisostearate (HLB 3), hexaglyceryl monolaurate (HLB 14.5), decaglyceryl monolaurate (HLB 15.5), decaglyceryl monomyristate (HLB 12.0), decaglyceryl monoisostearate (HLB 12.0), decaglyceryl monooleate (HLB 12.0), decaglyceryl distearate (HLB 9.5), and decaglyceryl diisostearate (HLB 10).

[0080] Examples of polyoxyethylene hydrogenated castor oils include PEG-40 hydrogenated castor oil (HLB 12.5), PEG-50 hydrogenated castor oil (HLB 13.5), PEG-60 hydrogenated castor oil (HLB 14.0), and PEG-100 hydrogenated castor oil (HLB 15.0).

[0081] The average number of moles of polyoxyethylene groups added in the polyoxyethylene alkyl ether is preferably 20 or more, 21 or more, 25 or more, or 30 or more from the viewpoint of emulsion stability and the like.

[0082] The amount of higher alcohol to be blended is not limited to the following, but for example, from the viewpoint of improving usability (e.g., reducing stickiness), it can be 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, or 0.4% by mass or more relative to the total amount of the cosmetic, and can be 2.0% by mass or less, 1.5% by mass or less, 1.0% by mass or less, or 0.8% by mass or less.

[0083] The A / S ratio, defined as the ratio of the molar amount (A) of the higher alcohol to the total molar amount (S) of the ionic surfactant and, if present, the nonionic surfactant, can be, for example, from the viewpoint of improving usability (e.g., reducing stickiness), more than 0, 0.3 or more, 0.5 or more, 0.7 or more, or 1.0 or more, and can be 4.0 or less, 3.5 or less, 3.0 or less, 2.5 or less, or 2.0 or less.

[0084] The higher alcohol is not particularly limited, but from the viewpoint of, for example, improving the formability of the interfacial film and ease of use (for example, reducing stickiness), it is preferable to use one that can form a solid or α-gel interfacial film at room temperature or higher together with an ionic surfactant and, if present, a nonionic surfactant, such as a higher alcohol that is solid at room temperature. Here, room temperature refers to a temperature in the range of 5°C to 35°C.

[0085] Examples of such higher alcohols that can be used include those with a carbon chain length of 16 or more, and specific examples include straight-chain or branched higher alcohols such as lauryl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, myristyl alcohol, oleyl alcohol, cetostearyl alcohol, monostearyl glycerin ether (batyl alcohol), 2-decyltetradecinol, lanolin alcohol, cholesterol, phytosterol, hexyldodecanol, isostearyl alcohol, and octyldodecanol. Among these, higher alcohols having a straight-chain saturated alkyl group having 18 or more or 19 or more carbon atoms are preferred, and behenyl alcohol is particularly preferred. These may be used alone or in combination.

[0086] <<Method for producing oil-in-water emulsion cosmetics>> The oil-in-water emulsion cosmetic of the present disclosure can be prepared by known methods such as aggregation methods or dispersion methods.

[0087] The aggregation method is a colloid preparation method that utilizes surface chemistry. It involves some means of supersaturating a homogeneously dissolved state to produce a dispersed phase. Specific techniques include microemulsion, HLB temperature emulsification, phase inversion emulsification, non-aqueous emulsification, D-phase emulsification, and liquid crystal emulsification. Here, the term "microemulsion" refers to a method for preparing an oil-in-water emulsion via microemulsion. Furthermore, "microemulsion" refers to a thermodynamically stable, water-continuous (O / W), bicontinuous, or oil-continuous (W / O) transparent phase in a system containing a surfactant, water, oil, and, optionally, an auxiliary agent such as a higher alcohol.

[0088] When the oil-in-water emulsion cosmetic of the present disclosure is obtained by the microemulsion method, a microemulsion is prepared by mixing water and a portion of the dispersion medium containing an optional water-soluble component, an oil, a surfactant, and an optional oil-soluble component such as a higher alcohol, and then the remainder of the dispersion medium is added to the microemulsion to dilute it, or the microemulsion is added to the remainder of the dispersion medium to dilute it, thereby producing an emulsion.

[0089] The temperature for forming the microemulsion phase can be 10° C. or higher, 15° C. or higher, or 20° C. or higher, and can be 85° C. or lower, 80° C. or lower, or 75° C. or lower. From the viewpoint of productivity, the temperature for forming the microemulsion phase is preferably in the range of 45° C. to 75° C., more preferably in the range of 50° C. to 70° C.

[0090] The dispersion method is a method of micronizing lumps of dispersed phase by mechanical force. Specifically, it is a method of emulsifying by utilizing the crushing force of an emulsifier. A dispersion method preferably used in the present disclosure can be, for example, a dispersion method by high-pressure emulsification, from the viewpoint of micronizing emulsion particles, reducing viscosity, etc. Here, high-pressure emulsification is a method in which an aqueous phase component and an oil phase component are pre-emulsified using a homomixer or the like, as necessary, and then an emulsion having fine emulsion particles is obtained under high pressure by high shear force using a high-pressure homogenizer such as a Manton-Gaulin, French press, or microfluidizer.

[0091] When the oil-in-water emulsion cosmetic of the present disclosure is obtained by high-pressure emulsification, a mixed liquid containing the above-mentioned water, ionic surfactant, oil, and optional components such as a nonionic surfactant and higher alcohol is prepared, and this mixed liquid is high-pressure emulsified under a pressure of 50 MPa or more, 80 MPa or more, or 100 MPa or more to prepare an emulsion.

[0092] Here, the mixed solution may be prepared by mixing water, an ionic surfactant, an oil, and optional ingredients such as a nonionic surfactant and a higher alcohol all at once, or by separately preparing an oily solution (oil phase part) containing oil, and optional oily ingredients such as a nonionic surfactant and a higher alcohol, and an aqueous solution (aqueous phase part) containing water, an ionic surfactant, and optional aqueous ingredients, and then adding the oily solution to this aqueous solution to prepare the mixed solution. Furthermore, in preparing the mixed solution, a heating treatment can be appropriately applied as necessary.

[0093] <<Usage forms of oil-in-water emulsion cosmetics>> The oil-in-water emulsion cosmetic of the present disclosure is not particularly limited in its form of use, as long as it can move oil droplets to the stratum corneum by electrophoresis, and examples thereof include low-viscosity liquids such as lotions or serums, and higher-viscosity liquids such as emulsions or ointments. Considering the feel during use and the speed at which oil droplets move due to electrophoresis, low-viscosity liquids such as lotions or serums are advantageous.

[0094] The cosmetic preparation of the present disclosure may be applied to the skin as is, or may be applied to the skin after being impregnated into a porous substrate. Here, "skin" in this disclosure refers to the skin of any part of the body, i.e., the surface of the body, and examples include the skin of the face (lips, eyes, nose, cheeks, forehead, etc.), neck, ears, hands, fingers, arms, legs, feet, chest, abdomen, back, buttocks, etc. Here, skin also includes nails, which have hardened due to changes in the keratin of the epidermis of the skin.

[0095] <Cosmetic-impregnated sheet> The cosmetic of the present disclosure can be provided as a cosmetic-impregnated sheet prepared by impregnating a porous substrate with the cosmetic. The porous substrate to be impregnated with the cosmetic is not particularly limited, and examples thereof include nonwoven fabrics, woven fabrics, knitted fabrics, and porous films or foams having interconnecting pores. These can be used alone or in combination of two or more.

[0096] The material of the porous substrate is not particularly limited, and examples thereof include natural fibers such as cotton, cellulose, wool, etc., polyester resins such as polyethylene terephthalate, polyolefin resins such as polyethylene, polyurethane resins, etc. These may be used alone or in combination of two or more, and may be processed.

[0097] The shape of the porous substrate is not particularly limited, and examples thereof include a sheet shape and a face mask shape.

[0098] The thickness of the porous substrate is not particularly limited as long as it is a thickness that allows oil droplets in the cosmetic to migrate electrophoretically to the stratum corneum, and can be, for example, 10 mm or less, 5 mm or less, or 1 mm or less, or 0.1 mm or more, 0.5 mm or more, or 0.7 mm or more.

[0099] The thickness of the porous substrate can be defined as the average value calculated by measuring the thickness of any part of the substrate at least five times using a high-precision Digimatic Micrometer (MDH-25MB, manufactured by Mitutoyo Corporation).

[0100] The porous substrate can also be specified by basis weight instead of thickness. The basis weight of the porous substrate is, for example, 300 g / m 2 Below 200g / m 2 or less than 100g / m 2 and 0.5 g / m 2 More than 5g / m 2 More than 10g / m 2 More than 30g / m 2 or more, or 50 g / m 2 It can be more than that.

[0101] <<Beauty method using a cosmetic or a cosmetic-impregnated sheet>> The cosmetic method of the present disclosure can be carried out by directly applying the oil-in-water emulsion cosmetic of the present disclosure to the skin, or by applying a cosmetic-impregnated sheet impregnated with such a cosmetic to the skin, and then applying to the application site a device (sometimes referred to as an "electric field generator") capable of generating an electric field between the skin and the cosmetic, thereby moving oil droplets contained in the cosmetic or sheet to the stratum corneum side of the skin. Here, "cosmetic" or "cosmetic method" in the present disclosure refers to a method for beautifying and adjusting the condition of the skin, and is different from methods of surgery, treatment, or diagnosis for humans.

[0102] The cosmetic method of the present disclosure allows oil droplets in the cosmetic to be transferred to the stratum corneum more uniformly and quickly by electrophoresis, compared to conventional methods in which cosmetics are simply applied to the skin. The cosmetic method of the present disclosure is particularly effective when using a cosmetic-impregnated sheet. When a sheet impregnated with an emulsion-based cosmetic is simply applied to the skin, the emulsified particles contained in the impregnated sheet are prevented from transferring to the skin by, for example, the mesh structure of the impregnated sheet. Therefore, in conventional cosmetic methods that simply apply an impregnated sheet to the skin, the emulsified particles containing the active ingredients are discarded without being consumed. In contrast, the cosmetic method of the present disclosure allows the emulsified particles in the impregnated sheet to be forced to transfer to the stratum corneum, allowing the active ingredients in the emulsified particles contained in the impregnated sheet to be utilized without waste.

[0103] The application method of the electric field generator can be determined, for example, based on the application time. For example, it is known that facial skin generally has a high sebum content in the T-zone (e.g., around the bridge of the nose or between the eyebrows) and is dry in the U-zone (e.g., around the cheeks or chin). For example, conventional beauty methods that simply apply cosmetics or cosmetic-impregnated sheets to the skin make it impossible to control the amount of oil, and therefore require the preparation of multiple types of cosmetics or cosmetic-impregnated sheets with different oil contents. In contrast, the beauty method disclosed herein allows the amount of oil transferred to the stratum corneum to be easily controlled depending on the application time of the electric field generator, eliminating the need to prepare multiple types of cosmetics or cosmetic-impregnated sheets and eliminating the need for a complicated beauty method. For example, a single type of cosmetic or cosmetic-impregnated sheet can be applied to facial skin, and the electric field generator can be applied to this application site only in the U-zone, which is prone to dryness, or the application time in the U-zone can be longer than that in the T-zone.

[0104] The application of the electric field generator to the skin can be performed based on at least one piece of information selected from, but not limited to, medical interview information, environmental information, and skin information. Here, "medical interview information" refers to information about the user's own life, such as personal information (e.g., age, sex, nationality, family composition), sleep information, bowel movement information, psychological information, skin concerns, dietary information, preference information, physiological information, schedule, beauty history, beauty goals, and other information other than the user's skin; "environmental information" refers to information about the user's living environment, such as outdoor or indoor work environment information (e.g., people, time, space, dust amount, air conditioner, electricity, blue light, air pressure), and climate environment information (e.g., location, season, weather, temperature, humidity, UV, pollen, PM2.5, air pressure, time, wind volume, snow accumulation, cloud cover, rainfall, yellow sand), and "skin information" refers to information obtained by a device or person that can determine the skin condition, such as at least one piece of skin-related information selected from shape, color, moisture content, sebum content, temperature, feel, pH, resident bacteria, reflected light, nutrients, blood flow, and elasticity. It should be noted that the "medical interview information" is not used to directly improve the user's illness, but is used to obtain information from the above information that will lead to cosmetic effects on the skin.

[0105] For example, the amount of sebum, which is one type of skin information, may differ between areas of the skin, such as the T zone and the U zone. Furthermore, because sebum, i.e., oil, typically does not conduct electricity well, the electrical conduction state differs between areas with a high sebum amount and areas with a low sebum amount (e.g., dry areas). Therefore, even when a constant voltage is applied to areas with a low sebum amount (e.g., dry areas) and areas with a high sebum amount, more oil in the cosmetic product can be applied to areas with a low sebum amount (e.g., dry areas) than to areas with a high sebum amount. Furthermore, for example, by having the electric field generator detect changes in current value based on differences in sebum amount, the electric field generator can be selectively applied to areas with a high electrical conduction rate, i.e., areas with a low sebum amount. In this case, the voltage used by the electric field generator to detect changes in current value and the voltage used to apply oil to the skin may be the same or different. When applying different voltages, for example, the voltage for checking skin information and the voltage for applying oil to the skin can be set separately in stages.

[0106] There are no particular limitations on the manner in which the cosmetic or cosmetic-impregnated sheet and the electric field generator are used. For example, the cosmetic or cosmetic-impregnated sheet can be applied directly to the skin, and then the electric field generator can be applied thereon. In this case, the electric field generator may be a movable, manual device or a detachable, fixed device.

[0107] There are no particular limitations on the movable manual device, and generally, devices consisting of a handle and an electrode unit, such as those disclosed in Patent Documents 2 to 4, can be used. The shape, size, material, and quantity of the handle and electrode unit can be selected appropriately depending on usability, design, etc. The electrode unit may be fixed to the device, or may be a rotating body such as that disclosed in Patent Document 5.

[0108] A removable fixed device may be fixed to the fingertips, face, neck, etc., on top of the applied cosmetic or cosmetic-impregnated sheet using, for example, tape such as Cellotape (trademark), hook-and-loop fasteners, adhesives, pressure-sensitive adhesives, double-sided tape, bands, etc., or may be used in a form that fits the skin, such as a face mask. Such fixed devices generally consist of an electrode unit and a support unit that supports the electrode unit, and the shape, size, material, quantity, etc. of these can be selected appropriately depending on usability, design, etc. Among these, a sheet-type electrode such as that described in Patent Document 6 is preferred as a fixed device from the standpoints of lightness, skin conformity, etc.

[0109] When a cosmetic-impregnated sheet is used, any of the following methods (1) to (4) can be used: (1) A sheet of a porous substrate pre-impregnated with a cosmetic is applied to the skin. (2) The porous substrate is applied to the skin, and then the substrate is impregnated with a cosmetic. (3) A porous substrate pre-impregnated with a cosmetic is applied to the electrode portion of the manual or fixed device described above. (4) A porous substrate is applied to the electrode portion of the manual or fixed device, and then the substrate is impregnated with a cosmetic.

[0110] The electric field generator can electrophoretically migrate charged oil droplets in the cosmetic to the stratum corneum of the skin when the cosmetic is present between the electrode and the skin, generating a weak current (waveform). The electric field generator generates a current (waveform) by repeatedly applying a pulse group (cluster wave) having multiple pulses (fundamental waves) of positive or negative polarity for a predetermined period of time, followed by a pulse group having pulses of a different polarity from the pulse group for a predetermined period of time. The maximum peak value (also referred to as peak amplitude) of the multiple pulses included in the electric field generated by these pulse groups is not particularly limited and can be, for example, 10 μA or more, 50 μA or more, or 100 μA or more, or 5 mA or less, 4 mA or less, 3 mA or less, 2 mA or less, or 1 mA or less. The combination of the peak values ​​of the multiple pulses can produce a pulse group having a waveform such as a rectangular wave, a triangular wave, or a sine wave, or a combination thereof. However, the combination must be one in which the total peak value of the pulses is biased towards the positive or negative polarity.

[0111] The electrodes of the electric field generator can be prepared using a material containing at least one selected from the group consisting of metals (e.g., aluminum, titanium, stainless steel, gold, silver, platinum, or metal alloys containing at least one of these), conductive polymers, conductive hydrated gels, conductive rubber, conductive particles, conductive fibers, and conductor-dispersed cosmetics. These materials may be compounds that are themselves conductive, or they may be polymers, gels, rubbers, particles, fibers, or liquids filled, dispersed, and / or coated with a conductive filler (e.g., conductive powders, conductive fibers, thin metal flakes, carbon particles, or metal, carbon, or conductive polymer coatings). Electrodes prepared using such materials may be processed as needed, provided that the skin-contacting surface is conductive.

[0112] The electric field generator may further include a device that generates at least one selected from, for example, heating, cooling, vibration, ultrasound, electromagnetic waves, plasma, magnetic force, mist, and light, and these may be applied to the skin simultaneously, sequentially, or alternately in combination with the electric field. In this case, it is preferable that the temperature range is 32°C to 70°C or 5°C to 15°C when a heating or cooling device is included, the vibration frequency is 1 Hz to 200 MHz when a vibration device is included, the wavelength is 450 nm to 750 nm when a light irradiation device is included, the magnetic flux density is 0.000001 T (Tesla) to 10 T (Tesla) when a magnetic generator is included, and the average particle size of the mist is 0.01 μm to 100 μm when a mist generator is included.

[0113] The electric field generator may have a function of detecting, for example, the above-mentioned skin condition, etc. In this case, the detected information can be provided to the user visually, vibratory, or auditorily by at least one selected from numerical values, light, color, vibration, sound, etc.

[0114] Information Output System The cosmetic method of the present disclosure can employ an information output system that includes a means for presenting the application method of the above-described electric field generator to the user as an image and a means for allowing the user to freely change the application method of the device to suit the user's preferences. Such an information output system can provide the user with, for example, an image of how to handle or use the electric field generator, information detected by the electric field generator (e.g., skin information), etc., and can optionally record, for example, the user's desired application conditions for the electric field generator, or provide the electric field generator with a desired current (waveform) based on the recorded application conditions. Here, in the present disclosure, "image" is not limited to still images and can also include moving images.

[0115] There are no particular limitations on the means for providing images in the information output system, and for example, monitor images, touch panel images, projected images, etc. can be used.

[0116] The information output system can record various information, such as the application method of the electric field generator, for example, the handling method and usage method of the electric field generator, the user's desired application conditions, and information detected by the electric field generator (e.g., skin information), and can transfer the recorded information to a recording medium other than the information output system. Transfer to the recording medium can be performed by wired or wireless means. The other recording medium may be, for example, a recording medium such as a memory card or hard disk built into the electric field generator, or a recording medium such as a memory card or hard disk located on a server owned by the user or an external server known as a cloud.

[0117] The information output system may be configured to receive the latest information, such as the application method of the electric field generator, via wired or wireless means, thereby providing the latest beauty treatment methods to the user.

[0118] Specific examples of such information output systems include electric field generators, beauty devices, medical devices, skin diagnostic devices, smartphones, mobile phones, tablet devices, PDAs (Personal Data Assistants), PDs (Portable Devices) such as iPod (registered trademark), PCs (Personal Computers), game consoles, and IoT devices such as smart speakers.

[0119] <<Information output program>> Such an information output system can be operated by an information output program that executes a procedure for presenting the application method of the electric field generator in the above-mentioned beauty treatment method to the user as an image and a procedure for optionally changing the application method of the electric field generator to suit the user's preferences. Such a program may further include a procedure for recording information on the application method of the electric field generator and transferring the information to a recording medium.

[0120] The images and recording media that can be operated by this information output program can be the same as those listed in the information output system described above. Similarly, the information output program may also include a procedure for transferring the information to a recording medium or a procedure for receiving the latest information, such as application methods of the electric field generator, by wired or wireless means.

[0121] The information output program disclosed herein can be installed as part of the software of IoT devices such as electric field generators, beauty devices, medical devices, skin diagnostic devices, smartphones, mobile phones, tablet devices, PDAs (Personal Data Assistants), PDs (Portable Devices) such as iPods (registered trademarks), PCs (Personal Computers), game consoles, and smart speakers, as described above. [Example]

[0122] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these. Note that, hereinafter, unless otherwise specified, the blending amounts are expressed in mass %.

[0123] Examples 1 to 4 and Comparative Example 1 The oil-in-water emulsion cosmetics obtained by the formulation and production method shown in Table 1 below were evaluated as follows, and the results are shown in Table 1.

[0124] The "A / S ratio" in the table can be calculated by dividing the molar amount of higher alcohol by the molar amount of nonionic surfactant and the molar amount of ionic surfactant. The "molar ratio of ionic surfactant to nonionic surfactant" can be calculated by dividing the molar amount of ionic surfactant by the molar amount of nonionic surfactant and the molar amount of ionic surfactant by the molar amount of nonionic surfactant. The "total amount of surface components" can be calculated by dividing the molar amount of ionic surfactant by the molar amount of nonionic surfactant and the molar amount of higher alcohol. The molecular weight of the ionic surfactant (anionic surfactant) used was 427.69, the molecular weight of the nonionic surfactant, POE(30) behenyl ether, was 1,646, and the molecular weight of the higher alcohol, behenyl alcohol, was 326.6.

[0125] Evaluation Method 1 (Evaluation of Zeta Potential) The zeta potential of the oil droplets (emulsion particles) in the cosmetic was measured using a Zeta sizer (manufactured by Malvern Instruments).

[0126] (Electrophoretic evaluation) Stainless steel electrodes were placed on both ends of the opening of a transparent resin pipe measuring 10 mm in diameter and 20 mm in height, covering the opening. A cosmetic was filled between the electrodes, and a constant voltage of 10 V was applied between the electrodes. The interface position of the opaque layer containing oil droplets (oil content) formed at this time was visually observed. The electrophoresis (electromigration) was evaluated based on the uniformity of the opaque layer interface and the distance between the interface position of the opaque layer and the surface of the positive electrode, using the following evaluation criteria. Here, grades A to C can be considered acceptable, and grade D can be considered unacceptable. Among the grades A to C, grade A is the most preferable, followed by grade B, and finally grade C.

[0127] A: The interface of the opaque layer was uniformly formed 10 minutes after voltage application, and the distance between the interface position of the opaque layer and the positive electrode was within 5 mm. B: The interface of the opaque layer was uniformly formed 10 minutes after application of voltage, and the distance between the interface position of the opaque layer and the positive electrode was more than 5 mm and within 10 mm. C: The interface of the opaque layer was uniformly formed 10 minutes after application of voltage, and the distance between the interface position of the opaque layer and the positive electrode was more than 10 mm and within 15 mm. D: The position of the interface of the cloudy layer could not be confirmed 10 minutes after voltage application.

[0128] (Property evaluation) After storage at 25°C for 4 weeks, the emulsion cosmetic in the sample tube was visually observed, and its properties were evaluated according to the following criteria.

[0129] A: No aggregates or gelation were found in the cosmetic. B: A small amount of aggregates or gelation was observed on the wall of the sample tube, but disappeared after shaking. C: Aggregates or gels were clearly observed in the cosmetic.

[0130] (Usability evaluation) Ten female expert panelists evaluated the usability (stickiness) of each emulsion cosmetic when it was applied directly to the face, according to the following evaluation criteria.

[0131] A: 0 to 3 people answered that they felt sticky. B: 4 to 6 people answered that they felt sticky. C: 7 to 10 people answered that they felt sticky.

[0132] (Evaluation of average particle size) The average particle size of the oil droplets in the cosmetic was measured using a Zeta sizer (manufactured by Malvern Instruments).

[0133] <Manufacturing method 1 for emulsion cosmetics> (Comparative Example 1) An oil-soluble solution was prepared by mixing and heating POE (30) behenyl ether as a nonionic surfactant, and liquid paraffin, dimethylpolysiloxane, and di(phytosteryl / octyldodecyl) lauroyl glutamate as oil components. This oil-soluble solution was then added to ion-exchanged water and stirred, followed by high-pressure emulsification at a pressure of 100 MPa using a high-pressure homogenizer, to prepare an oil-in-water emulsion cosmetic.

[0134] Example 1 An oil-soluble solution was prepared by mixing and heating POE (30) behenyl ether as a nonionic surfactant, and liquid paraffin, dimethylpolysiloxane, and di(phytosteryl / octyldodecyl) lauroyl glutamate as oil components. A water-soluble solution was prepared by mixing and heating sodium stearoyl methyl taurate as an ionic surfactant, and ion-exchanged water. The oil-soluble solution was then added to this water-soluble solution and stirred. After stirring, high-pressure emulsification was carried out at 100 MPa using a high-pressure homogenizer to prepare an oil-in-water emulsion cosmetic.

[0135] Examples 2 to 4 Oil-in-water emulsion cosmetics of Examples 2 to 4 were prepared in the same manner as Example 1, except for changing the formulation to that shown in Table 1. Note that behenyl alcohol as a higher alcohol was added when the oil-soluble solution was prepared, and the moisturizer and preservative were added when the water-soluble solution was prepared.

[0136] [Table 1]

[0137] <result> As is clear from the results in Table 1, the cosmetic of Comparative Example 1, which did not contain an ionic surfactant, did not exhibit electrophoretic properties. On the other hand, the cosmetic of Examples 1 to 4, which contained an ionic surfactant, exhibited electrophoretic properties and formed the interface of a uniform, opaque layer containing oil. This suggests that if such a cosmetic is applied to the stratum corneum using electrophoresis, the oil will be uniformly applied to the stratum corneum.

[0138] When Example 2 was compared with Examples 3 and 4, Example 2 had superior electrophoretic mobility, confirming that the electrophoretic mobility can be adjusted by the ratio of the ionic surfactant used.

[0139] Furthermore, the cosmetics of Examples 2 and 4, which used higher alcohols, were less sticky and easier to use than the cosmetics of Examples 1 and 3, which did not contain higher alcohols. This confirms that the use of higher alcohols can contribute to improving the usability of oil-in-water emulsion cosmetics.

[0140] Examples 5 and 6 In addition to the above evaluations, the oil-in-water emulsion cosmetics obtained using the formulations and manufacturing methods shown in Table 3 below were also evaluated for the effects of the application time of the electric field generator and the size of the oil droplets in the cosmetics on the amount of oil penetration, and the results are shown in Table 3.

[0141] Evaluation Method 2 (Evaluation of infiltration amount) The skin on the inside of the arms of four subjects was washed with soap, and 15 minutes later, a nonwoven fabric (cotton and polyester blended in a ratio of 70:30, basis weight 70 g / m) measuring 30 mm x 30 mm was soaked in 0.5 ml of the cosmetic composition of Example 5 or 6. 2 The nonwoven fabric (of which the nonwoven fabric is a nonwoven fabric of the present invention) was applied to cleansed skin under the conditions shown in Table 2 below. The electric field generator used was an Elixir (trademark) Superieur Beauty Device manufactured by Shiseido Co., Ltd., in HIGH mode.

[0142] Here, "electric field generator application time" in Table 2 refers to the time during which voltage is applied after the electric field generator is applied to the cosmetic-impregnated nonwoven fabric, except for condition 5, and "resting time" refers to the time during which the subject is made to wait in the test room (temperature 23°C ± 1°C, relative humidity 50% ± 2%) after treatment with the electric field generator without applying the electric field generator to the cosmetic-impregnated nonwoven fabric.

[0143] Furthermore, condition 1 in Table 2 is a reference condition in which no cosmetic is applied, conditions 2, 3, and 6 are conditions for evaluating a state in which a cosmetic-impregnated nonwoven fabric is applied to the skin and a voltage is applied using an electric field generator, condition 4 is a condition for evaluating a state in which a cosmetic-impregnated nonwoven fabric is applied to the skin but an electric field generator is not applied, and condition 5 is a condition for evaluating a state in which a cosmetic-impregnated nonwoven fabric is applied to the skin but no voltage is applied to the electric field generator, i.e., a state in which only the pressure of the electric field generator is applied to the nonwoven fabric.

[0144] [Table 2]

[0145] After the conditions in Table 2, if a nonwoven fabric was applied, it was removed, and the skin on the inside of the arm was washed again with soap. After 4 hours, the stratum corneum of the skin on the inside of the arm (or, if a nonwoven fabric was applied, the stratum corneum of the skin on the inside of the arm in the area where the nonwoven fabric was applied) was peeled off using a soft tissue adhesive (Aron Alpha (trademark) A "Sankyo", manufactured by Daiichi Sankyo Co., Ltd.), and this was used as a stratum corneum test specimen.

[0146] This stratum corneum specimen was placed in a container, 500 μL of chloroform was added, and ultrasonic waves were applied for 15 minutes to extract the oil from the cosmetic that had penetrated into the stratum corneum specimen.The chloroform phase was then collected and used as an analytical sample for the amount of oil penetration.A solution of dimethylpolysiloxane added to chloroform was used as the standard solution.

[0147] The quantitative value of the oil penetration amount was calculated as follows. First, the standard solution was analyzed using GC / MS analysis in scan (m / z 100-800) mode, and a characteristic silicone spectrum with 74 mass periods of m / z 147, 221, 295, and 369 was detected. From this result, the SIM mode was set to m / z 369, and the integrated value of the peak detected in the retention time range of 8.5 to 11 minutes in the obtained chromatogram was quantified. Here, the GC / MS analysis was performed using the following equipment and analytical conditions: GC / MS equipment: 7890B system (MS: 5977A MSD) (Agilent Technologies) Carrier gas: Helium Flow rate: 1.4mL / min Column: DB 35MS UI (30 m (L), 0.25 mm (ID), 0.25 μm (F)), (Agilent Technologies) Column temperature: 80°C (hold time 2 minutes) to 320°C (hold time 5 minutes), heated at 20°C / min

[0148] Based on the obtained quantitative values ​​of the amount of oil penetration, the amount of oil penetration (%) was calculated using the following formula 2, and the average values ​​for four subjects are shown in Table 3 and Figure 3. Note that, with regard to the amount of penetration in Table 3, Example 5 shows the amount of penetration based on condition 6, and Example 6 shows the amount of penetration based on condition 3: Penetration amount (%) = (quantitative value of oil penetration amount under any of conditions 1 to 6) × 100 / (quantitative value of oil penetration amount under condition 1) ... Equation 2

[0149] <Manufacturing method 2 for emulsion cosmetics> Example 5 An oil-soluble solution was prepared by mixing and heating the nonionic surfactant POE (30) behenyl ether, the higher alcohol behenyl alcohol, and the oils liquid paraffin, dimethylpolysiloxane, and di(phytosteryl / octyldodecyl) lauroyl glutamate. An aqueous solution was prepared by mixing and heating the ionic surfactant sodium stearoyl methyl taurate, the humectants 1,3-butylene glycol, dipropylene glycol, and glycerin, the preservatives phenoxyethanol and ethanol, the thickeners xanthan gum and crystalline cellulose, the pH buffers sodium citrate and citric acid, the pharmaceuticals dipotassium glycyrrhizinate and tocopherol acetate, and ion-exchanged water. The oil-soluble solution was then added to the aqueous solution and stirred with a homogenizer for 2 minutes to prepare an oil-in-water emulsion cosmetic.

[0150] Example 6 The oil-in-water emulsion cosmetic of Example 6 was prepared in the same manner as in Example 5, except that the oil-soluble solution was added to the water-soluble solution and stirred, and then high-pressure emulsification was carried out at a pressure of 100 MPa using a high-pressure homogenizer.

[0151] [Table 3]

[0152] <result> From the results in Table 3, it can be inferred that the cosmetics of Examples 5 and 6 also performed well in the electrophoresis test, and that if such cosmetics are applied to the stratum corneum using electrophoresis, the oil will be applied evenly to the stratum corneum.

[0153] In the examples of the present disclosure, di(phytosteryl / octyldodecyl) lauroyl glutamate, a water-containing oil with properties similar to those of the intercellular lipid components that make up the stratum corneum, was used as the oil. Therefore, the results under conditions 1 and 4 in Figure 3 confirmed that simply applying a cosmetic containing this water-containing oil to the skin allowed the oil to penetrate into the skin to a certain extent. However, the results under condition 6 in Figure 3, in which the cosmetic of Example 5 was used, confirmed that when the average particle diameter of the oil droplets was large, on the order of 10 μm, the oil hardly penetrated any further, even when a voltage was applied using an electric field generator.

[0154] On the other hand, the results of conditions 2 and 3 in Figure 3 using the cosmetic of Example 6 confirmed that when the average particle size of the oil droplets is small, on the order of nanometers, the oil penetrates into the skin to a greater extent. In addition, as can be seen by comparing conditions 2 and 3, it was also confirmed that the amount of oil that penetrates into the skin can be adjusted by changing the application time of the electric field generator.

[0155] <Formulation example of an oil-in-water emulsion cosmetic for skin care using electrophoresis> Below are examples of formulations of cosmetics according to the present disclosure, but the present disclosure is not limited to these examples. Note that all of these exhibited electrophoretic properties.

[0156] <Formulation example 1: Lotion> [Table 4]

[0157] (Manufacturing method of lotion) The nonionic surfactant, higher alcohol, and oil listed in Table 4 were mixed and heated to dissolve to prepare an oil-soluble solution, and then the ionic surfactant, moisturizer, and a portion of the ion-exchanged water were mixed and heated to dissolve to prepare a water-soluble solution. The oil-soluble solution was added to the obtained water-soluble solution, and an emulsion was prepared by stirring, followed by cooling. Next, a solution prepared by adding a drug, thickener, stabilizer, pH buffer, and preservative to the remaining ion-exchanged water and dissolving it was added to the emulsion to prepare a lotion.

[0158] <Formulation example 2: Sunscreen cosmetics> [Table 5]

[0159] (Method of manufacturing sunscreen cosmetics) An oil-soluble solution was prepared by mixing and heating the nonionic surfactant, higher alcohol, oil, and UV absorber listed in Table 5 to dissolve them. Next, an ionic surfactant, moisturizer, and a portion of the ion-exchanged water were mixed and heated to dissolve them to prepare a water-soluble solution. The oil-soluble solution was added to the resulting water-soluble solution and stirred, followed by high-pressure emulsification at 100 MPa using a high-pressure homogenizer to prepare an emulsion, which was then cooled. Next, a solution prepared by dissolving a pH buffer, thickener, and preservative in the remaining ion-exchanged water was added to the emulsion to prepare a sunscreen cosmetic.

[0160] <Formulation example 3: Gel> [Table 6]

[0161] (Gel manufacturing method) The nonionic surfactant, higher alcohol, and oil listed in Table 6 were mixed and heated to dissolve, to prepare an oil-soluble solution. Next, the ionic surfactant, humectant, and a portion of the ion-exchanged water were mixed and heated to dissolve, to prepare a water-soluble solution. The oil-soluble solution was added to the resulting water-soluble solution and stirred to prepare an emulsion, which was then cooled. Next, a solution prepared by dissolving a drug, thickener, preservative, and pH buffer in the remaining ion-exchanged water was added to the emulsion to prepare a gel.

[0162] <Formulation example 4: Makeup remover> [Table 7]

[0163] (Method for manufacturing makeup remover cosmetics) An oil-soluble solution was prepared by mixing and dissolving the nonionic surfactant and oil listed in Table 7, and then an ionic surfactant, preservative, moisturizer, pH buffer solution, stabilizer, and ion-exchanged water were mixed and dissolved to prepare a water-soluble solution. The oil-soluble solution was added to the obtained water-soluble solution and stirred to prepare an emulsion, and the makeup remover cosmetic was then added to the emulsion.

[0164] Formulation example 5: Hair care cosmetics [Table 8]

[0165] (Method of manufacturing hair care cosmetics) The nonionic surfactants and oils listed in Table 8 were mixed and heated to dissolve, preparing an oil-soluble solution. The ionic surfactants, moisturizers, and a portion of the ion-exchanged water were then mixed and heated to dissolve, preparing a water-soluble solution. Next, high-pressure emulsification was performed at 100 MPa using a high-pressure homogenizer to prepare an emulsion, which was then cooled. A solution of a pH buffer and a preservative dissolved in the remaining ion-exchanged water was then added to the emulsion to prepare a hair care cosmetic.

[0166] Formulation Example 6: Sheet mask cosmetics [Table 9]

[0167] (Method of manufacturing sheet mask cosmetics) The nonionic surfactant, oil, higher alcohol, and fragrance listed in Table 9 were mixed and heated to dissolve, preparing an oil-soluble solution. The ionic surfactant, moisturizer, and a portion of the ion-exchanged water were then mixed and heated to dissolve, preparing a water-soluble solution. The heated oil-soluble solution was then added to the heated water-soluble solution and stirred to prepare an emulsion (microemulsion). The remaining ion-exchanged water was then dissolved in a pH buffer and a preservative, and the emulsion was then added to prepare a composition. The resulting composition was impregnated into a nonwoven fabric to prepare a sheet mask cosmetic. [Explanation of symbols]

[0168] 1. Stratum corneum 2 water 3 oil droplets 4. Electric field generator

Claims

1. a dispersion medium comprising water, and Oil droplets dispersed in the dispersion medium An oil-in-water emulsion cosmetic comprising: the oil droplets contain an ionic surfactant and an oil; the ionic surfactant is a sulfonate-type anionic surfactant, The content of the ionic surfactant is 0.1% by mass or more relative to the total amount of the cosmetic, and the content of the oil component is 0.5% by mass or more relative to the total amount of the cosmetic. The oil-in-water emulsion cosmetic is used to care for the skin by moving the oil droplets using electrophoresis and applying them to the stratum corneum.

2. The cosmetic preparation according to claim 1 , wherein the oil droplets further contain a nonionic surfactant.

3. 3. The cosmetic preparation according to claim 2, wherein the molar ratio of the ionic surfactant to the nonionic surfactant is 90:10 to 10:

90.

4. A cosmetic described in any one of claims 1 to 3, wherein the oil droplets further contain a higher alcohol having a carbon chain length of 16 or more.

5. The cosmetic preparation according to any one of claims 1 to 4, wherein the anionic surfactant is an N-acylmethyl taurine salt.

6. The cosmetic preparation according to any one of claims 1 to 5, wherein the oil component comprises a water-containing oil.

7. The cosmetic preparation according to any one of claims 1 to 6, wherein the oil droplets have an average particle size of 200 nm or less.

8. The cosmetic preparation according to any one of claims 1 to 7, which is used by impregnating a porous substrate.

9. A porous substrate impregnated with the cosmetic according to any one of claims 1 to 8, The cosmetic-impregnated sheet is used to care for the skin by moving the oil droplets using electrophoresis and applying them to the stratum corneum.

10. A device capable of generating an electric field between the cosmetic composition according to any one of claims 1 to 8 or the sheet according to claim 9 is applied to the skin, and the device is then applied to the skin to move oil droplets contained in the cosmetic composition or the sheet to the stratum corneum side of the skin. Beauty method.

11. The cosmetic method according to claim 10, wherein the skin is facial skin, and the application of the device is performed based on at least one information selected from medical interview information, environmental information, and skin information.

12. The cosmetic method according to claim 10 or 11, wherein the method of applying the device is determined based on the application time.

13. The cosmetic method according to claim 11, wherein the skin information is at least one selected from shape, color, moisture content, sebum content, temperature, feel on use, pH, resident bacteria, reflected light, nutrients, blood flow, and elasticity.

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