Oil-based emulsions in water

Abstract

Provided is an oil-in-water emulsion composition having excellent storage stability.　The present invention provides an oil-in-water emulsion composition containing: an oily component that contains (a1) cholesterol, (a2) a higher alcohol, and (a3) a hydrocarbon; a surfactant that contains (b1) polyoxyethylene alkyl ether; and an aqueous component, wherein the content of the component (a1) is 0.7-14 mass% of the total mass of the oily component, and the content of the component (b1) is 0.6-2.8 mass% of the total mass of the emulsion composition.

Description

【Technical Field】 【0001】 The present invention relates to an oil-in-water type emulsion composition. 【Background Art】 【0002】 Cholesterol is one of the components that form a lamellar structure in the stratum corneum of the epidermis and plays an important role in maintaining the barrier function. It is considered that when the cholesterol synthesis ability in the epidermis decreases, the barrier function decreases and the recovery ability from rough skin decreases. Therefore, cholesterol is widely formulated in cosmetics, quasi-drugs, pharmaceuticals, etc. in expectation of maintaining the barrier function and improving rough skin and the like. However, cholesterol is a solid oil-soluble substance at room temperature, has problems such as low solubility in cosmetic bases (especially aqueous cosmetic bases) and being likely to precipitate during storage, and there is a problem that only a small amount can be formulated. 【0003】 Various methods for stably formulating cholesterol in cosmetics have been studied. For example, Patent Document 1 discloses that a cholesterol-containing preparation excellent in storage stability can be obtained by using a liquid oil having an IOB value of a certain value or more. Further, Patent Document 2 discloses a hair cosmetic in which cholesterol is formulated together with a specific nonionic surfactant and an oil agent. However, even with these techniques, there are problems such as insufficient long-term storage stability and limited usable oily bases. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2012-82150 【Patent Document 2】 Japanese Patent Application Laid-Open No. 2016-188183 【Summary of the Invention】 【0005】 Under these circumstances, there is a need for novel oil-in-water emulsion compositions containing cholesterol. 【0006】 The present invention includes the following embodiments. [1] comprising an oily component containing (a1) cholesterol, (a2) higher alcohols, and (a3) ​​hydrocarbons, a surfactant containing (b1) polyoxyethylene alkyl ether, and an aqueous component, The content of component (a1) is 0.7 to 14% by mass of the total mass of the oily components. An oil-in-water emulsion composition wherein the content of component (b1) is 0.6 to 2.8% by mass of the total mass of the emulsion composition. [2] The (b1) component comprises a polyoxyethylene alkyl ether having an HLB value of 10 to 20. The emulsified composition according to [1], wherein the content of component (b1) is 0.7 to 2.5% by mass of the total mass of the emulsified composition. [3] The emulsified composition according to [1] or [2], wherein the content of component (a1) is in the range of 3 to 12% by mass of the total mass of the oily components. [4] The emulsifying composition according to any one of [1] to [3], wherein the (b1) component has an alkyl group having 12 to 24 carbon atoms. [5] The emulsifying composition according to any one of [1] to [4], wherein the (b1) component is one or more compounds selected from the group consisting of polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene stearyl ether, and polyoxyethylene behenyl ether. 【0007】 [6] The emulsifying composition according to any one of [1] to [5], wherein the component (a2) has an alkyl group having 12 to 24 carbon atoms. [7] The emulsified composition according to any one of [1] to [6], wherein the (a3) ​​component is an α-olefin oligomer. [8] The emulsified composition according to any one of [1] to [7], wherein the content of component (a1) is in the range of 0.3 to 1.5% by mass of the total mass of the emulsified composition. [9] The content of component (a2) is 0.2 to 6.5% by mass of the total mass of the oily components, The emulsified composition according to any one of [1] to [8], wherein the content of component (a3) ​​is 10% by mass or more of the total mass of the oily components.

[10] The emulsified composition according to any one of [1] to [9], wherein the component (a3) ​​is a hydrocarbon that is liquid at 25°C and accounts for 10% by mass or more of the total mass of the oily components that are liquid at 25°C contained in the emulsified composition. 【0008】

[11] The emulsified composition according to

[10] , wherein the component (a3) ​​is in the range of 10 to 60% by mass of the total mass of the oily components that are liquid at 25°C contained in the emulsified composition.

[12] The emulsified composition according to

[10] or

[11] , wherein the oily component that is liquid at 25°C is a hydrocarbon and an ester oil that are liquid at 25°C.

[13] The emulsified composition according to any one of [1] to

[12] , wherein the content of the oily component is in the range of 7 to 45% by mass of the total mass of the emulsified composition.

[14] The emulsified composition according to

[10] , wherein the content of the liquid oily component at 25°C is in the range of 5 to 40% by mass of the total mass of the emulsified composition.

[15] The emulsifying composition according to any one of [1] to

[14] , wherein the (b1) component is a polyoxyethylene alkyl ether having a number average number of added moles of oxyethylene groups of 10 to 30.

[16] comprising an oily component containing (a1) cholesterol, (a2) higher alcohols, and (a3) ​​hydrocarbons, a polyoxyethylene alkyl ether having a number average number of added moles of oxyethylene groups of 10 to 30, and an aqueous component, The content of component (a1) is 0.7 to 14% by mass of the total mass of the oily components. An oil-in-water emulsion composition in which the content of component (b1-1) is 0.6 to 2.8% by mass of the total mass of the emulsion composition.

[17] An emulsified composition according to any of [1] to

[15] , which is a cosmetic.

[18] An emulsified composition according to any one of [1] to

[15] , which is a topical skin preparation. [Effects of the Invention] 【0009】 The present invention has one or more of the following effects. (1) The present invention provides a novel oil-in-water emulsion composition containing cholesterol. The oil-in-water emulsion composition can be suitably used as a cosmetic, quasi-drug, pharmaceutical, etc. (for example, a cosmetic or topical skin preparation). (2) An oil-in-water emulsion composition with excellent storage stability is provided. In a preferred embodiment, the oil-in-water emulsion composition has long-term storage stability. (3) An oil-in-water composition with good storage stability is obtained, such as suppression of solute precipitation at low temperatures, suppression of viscosity changes at low temperatures, suppression of viscosity changes at room temperature, and suppression of phase separation at high temperatures. [Modes for carrying out the invention] 【0010】 <<Oil-in-water emulsion composition>> One embodiment of the present invention, an oil-in-water (O / W) emulsion composition (hereinafter also simply referred to as "emulsification composition"), comprises an oily component containing (a1) cholesterol, (a2) a higher alcohol, and (a3) ​​a hydrocarbon, a surfactant containing (b1) a polyoxyethylene alkyl ether, and an aqueous component. In one embodiment of the oil-in-water emulsion composition, the content of component (a1) is 0.7 to 14% by mass of the total mass of the oily component, and the content of component (b1) (polyoxyethylene alkyl ether) is 0.6 to 2.8% by mass of the total mass of the emulsion composition. The following describes each component of the oil-in-water emulsion composition of the present invention. 【0011】 <<Oil phase addition ingredients>> The oil-in-water emulsion composition of one embodiment of the present invention includes an oily component (component A) and a surfactant (oil-phase additive surfactant) (component B). In this specification, "oil-based component" means a component that is generally used as an oil-based component in the field of cosmetics. For example, it refers to a component whose solubility in water at 25°C is less than 0.1% by mass (less than 1 g / L). Examples of oil-based components (component A) in the present invention include (a1) cholesterol, (a2) higher alcohols, and (a3) ​​hydrocarbons, as well as additional oil-based components such as (a4) ester oils, which may be added as needed. 【0012】 Examples of surfactants in the present invention include (b1) polyoxyethylene alkyl ether and (b2) any other surfactants that may be added as needed. 【0013】 <a 油性成分> [(a1) Cholesterol] The cholesterol contained in the oil-in-water type emulsion composition in the present invention is preferably 0.1 to 2% by mass, more preferably 0.2 to 2% by mass, still more preferably 0.3 to 1.7% by mass, even more preferably 0.4 to 1.3% by mass, and particularly preferably 0.4 to 1.0% by mass, based on the total mass of the emulsion composition. Further, the cholesterol is 0.7 to 14% by mass, preferably in the range of 1.4 to 14% by mass, more preferably in the range of 2 to 12% by mass, still more preferably in the range of 3 to 12% by mass, even more preferably in the range of 3 to 9% by mass, and particularly preferably in the range of 3 to 8% by mass, based on the total mass of the oily component. When the content of cholesterol contained in the oil-in-water type emulsion composition in the present invention is 0.1 to 2% by mass in the whole emulsion composition or 0.7 to 14% by mass based on the total mass of the oily component, it can have skin care effects such as enhancing the skin barrier function, suppressing water evaporation from the inside of the skin, and enhancing the moisturizing power. 【0014】 [(a2) Higher alcohol] As the higher alcohol, it preferably contains a higher alcohol having 12 to 22 carbon atoms, more preferably 14 to 22 carbon atoms, and still more preferably 16 to 22 carbon atoms. The higher alcohol is preferably a linear one, more preferably a linear higher alcohol having 12 to 22 carbon atoms (more preferably 14 to 22 carbon atoms, still more preferably 16 to 22 carbon atoms). Specifically, cetyl alcohol, stearyl alcohol, cetostearyl alcohol, behenyl alcohol, etc. can be mentioned. Among these, from the viewpoints of stability or safety, it is more preferable to contain behenyl alcohol. The higher alcohol may be used alone or in combination of two or more. If the oil-in-water type emulsion composition contains a higher alcohol, it can maintain the viscosity at high temperatures and has good high-temperature stability. 【0015】 The higher alcohol contained in the oil-in-water emulsion composition of the present invention is preferably 0.2 to 6.5% by mass of the total mass of the oily components, more preferably 0.5 to 5% by mass, even more preferably in the range of 0.7 to 4.3% by mass, particularly preferably in the range of 1.4 to 4.3% by mass, and may also be 1.4 to 2.9% by mass. If the higher alcohols contained in the oil-in-water emulsion composition of the present invention fall within the above range, a good balance is achieved in terms of high-temperature stability and low-temperature stability, improving the stability of the emulsion composition. 【0016】 [(a3) Hydrocarbons] The hydrocarbons included in the oil-in-water emulsion composition of the present invention are not particularly limited, and examples include liquid paraffin, squalane, α-olefin oligomer, petrolatum, and microcrystalline wax. The hydrocarbons may be used individually or in combination of two or more. 【0017】 Among these hydrocarbons, it is preferable that the oily component is liquid at 25°C. For example, at least one selected from liquid paraffin, squalane, and α-olefin oligomer is preferred, and α-olefin oligomer is even more preferred in terms of stability. In this specification, "liquid at 25°C" refers to a substance whose viscosity value, measured with a Type B viscometer (rotor No. 2) at 25°C and 1 atmosphere, is 7000 mPa·s or less. 【0018】 If the oil-in-water emulsion composition of the present invention contains hydrocarbons, the decrease in viscosity at room temperature (25°C) can be suppressed. 【0019】 The hydrocarbons contained in the oil-in-water emulsion composition of the present invention are preferably 10% by mass or more of the total mass of the oily components, preferably 10 to 90% by mass, more preferably 10 to 50% by mass, even more preferably 15 to 40% by mass, particularly preferably in the range of 20 to 35% by mass, and may also be in the range of 20 to 25% by mass. 【0020】 In one embodiment, the hydrocarbon is an oily component that is liquid at 25°C, preferably at least 10% by mass of the total mass of the oily component that is liquid at 25°C, more preferably at 10 to 90% by mass of the total mass of the oily component that is liquid at 25°C, even more preferably at 10 to 70% by mass of the total mass of the oily component that is liquid at 25°C, even more preferably at 10 to 60% by mass of the total mass of the oily component that is liquid at 25°C, particularly preferably at 15 to 40% by mass of the total mass of the oily component that is liquid at 25°C, and may also be at 20 to 30% by mass of the total mass of the oily component that is liquid at 25°C, or 22 to 27% by mass of the total mass of the oily component that is liquid at 25°C. If the hydrocarbon content in the oily component that is liquid at 25°C is within the above range, viscosity reduction at room temperature can be suppressed, and storage stability can be improved at low, room, and high temperatures. 【0021】 [Additional oily ingredients] [(a4) Ester oil] The oil-in-water emulsion composition of the present invention may contain an ester oil. Examples of ester oils used in the present invention include cetyl 2-ethylhexanoate, ethylhexyl palmitate, 2-hexyldecyl 2-ethylhexanoate, octyldodecyl myristate, 2-hexyldecyl myristate, isononyl isononanoate, ethylhexyl isononanoate, isodecyl pivalate, isostearyl pivalate, 2-hexyldecyl stearate, isostearyl isostearate, isopropyl isostearate, pentaerythritol tetraisostearate, glyceryl tri-2-ethylhexanoate, caprylic / capric triglyceride, myristyl myristate, cetyl palmitate, and the like. Ester oils may be used individually or in combination of two or more types. 【0022】 Furthermore, the ester oil used in the present invention is preferably an oily component that is liquid at 25°C. Specifically, among the ester oils listed above, examples include cetyl 2-ethylhexanoate, ethylhexyl palmitate, 2-hexyldecyl 2-ethylhexanoate, octyldodecyl myristate, 2-hexyldecyl myristate, isononyl isononanoate, ethylhexyl isononanoate, isodecyl pivalate, isostearyl pivalate, 2-hexyldecyl stearate, isostearyl isostearate, isopropyl isostearate, pentaerythritol tetraisostearate, glyceryl tri-2-ethylhexanoate, and caprylic / capric triglyceride. 【0023】 From the viewpoint of stability, the content of the liquid oily component at 25°C is preferably in the range of 50 to 100% by mass of the total mass of the oily component, more preferably in the range of 60 to 95% by mass, and even more preferably in the range of 65 to 90% by mass. 【0024】 Furthermore, from the viewpoint of stability, the content of the liquid oily component at 25°C is preferably in the range of 5 to 40% by mass of the total mass of the emulsified composition, more preferably in the range of 7 to 35% by mass, and even more preferably in the range of 10 to 30% by mass. The oily component content is preferably in the range of 7 to 45% by mass of the total mass of the emulsified composition, more preferably in the range of 9 to 40% by mass, and even more preferably in the range of 12 to 35% by mass. 【0025】 For example, in the present invention, the oily component that is liquid at 25°C may be composed of hydrocarbons and ester oils. For example, when the oily component that is liquid at 25°C is composed of hydrocarbons and ester oils, the amount of the oily component that is liquid at 25°C is the sum of the amount of hydrocarbons and the amount of ester oils. 【0026】 The oil-in-water emulsion composition may contain, in addition to the ester oils mentioned above, other oily components such as olive oil, shea butter, grape seed oil, waxes such as jojoba oil, beeswax, and candelilla wax, fatty acids such as myristic acid, palmitic acid, and stearic acid, and silicone oil, to the extent that it does not impair the effects of the present invention. The other additional oily components may be liquid at 25°C or solid at 25°C. 【0027】 <b 界面活性剤(油相添加界面活性剤)> [(b1) Polyoxyethylene alkyl ether] The oil-in-water emulsion composition of the present invention contains a polyoxyethylene alkyl ether as a surfactant. The polyoxyethylene alkyl ether is usually added to the oil phase. 【0028】 The polyoxyethylene alkyl ether is preferably a polyoxyethylene alkyl ether having an alkyl group with 12 to 24 carbon atoms, and more preferably one having an alkyl group with 14 to 22 carbon atoms. The alkyl group may be a linear alkyl group or a branched alkyl group, but a linear alkyl group is preferred. Specific examples include polyoxyethylene lauryl ether (C12), polyoxyethylene myristyl ether (C14), polyoxyethylene stearyl ether (C18), and polyoxyethylene behenyl ether (C22). Furthermore, these polyoxyethylene alkyl ethers are preferably those with a number-average number of added moles of oxyethylene groups (hereinafter also referred to as "EO") of 2 to 30, more preferably 5 to 30, even more preferably 10 to 30, and particularly preferably 15 to 30. Polyoxyethylene alkyl ethers may be used individually or in combination of two or more types. Among these, the polyoxyethylene alkyl ether contained in the oil-in-water emulsion composition of the present invention is more preferably polyoxyethylene behenyl ether in terms of stability, and polyoxyethylene behenyl ether having a number-average number of added moles of EO of 10 to 30 (more preferably 12 to 30, and even more preferably 15 to 30) is particularly preferred. Furthermore, the polyoxyethylene alkyl ether preferably includes a polyoxyethylene alkyl ether having an HLB (Hydrophile-Lipophile Balance) value of 10 to 20 (preferably 11 to 20, more preferably 12 to 18). In one embodiment, 50% by mass or more (for example, 60% by mass or more, or 70% by mass or more, or 80% by mass or more) of the total mass of polyoxyethylene alkyl ether contained in the oil-in-water emulsion composition is polyoxyethylene alkyl ether having an HLB value within the above range. In one embodiment, the polyoxyethylene alkyl ether contained in the oil-in-water emulsion composition consists solely of polyoxyethylene alkyl ether having an HLB value within the above range. In this specification, unless otherwise specified, the HLB value is determined experimentally by comparing the emulsifying power with that of a standard sample. 【0029】 If an oil-in-water emulsion composition contains polyoxyethylene alkyl ether as a surfactant, it is possible to suppress solute precipitation at low temperatures and phase separation at high temperatures, thereby obtaining a stable oil-in-water emulsion composition at both low and high temperatures. 【0030】 The polyoxyethylene alkyl ether content is 0.6 to 2.8% by mass of the total mass of the emulsified composition, may be 0.7 to 2.5% by mass, and preferably 1.0 to 2.0% by mass. If the polyoxyethylene alkyl ether content in the oil-in-water emulsion composition of the present invention is within the above range, the effect of suppressing solute precipitation and viscosity changes at low temperatures, and suppressing phase separation at high temperatures, can be more preferably obtained. Furthermore, if the polyoxyethylene alkyl ether content in the oil-in-water emulsion composition of the present invention is 0.7 to 2.5% by mass, and even more specifically 1.0 to 2.0% by mass, a composition that is more stable for a longer period of time can be obtained at low temperatures, room temperature, and high temperatures. 【0031】 (b1) The ratio (mass ratio) of polyoxyethylene alkyl ether to oily component [(b1) / oily component] is preferably in the range of 0.035 / 1 to 0.20 / 1, more preferably in the range of 0.05 / 1 to 0.18 / 1, and even more preferably in the range of 0.07 / 1 to 0.14 / 1. An oil-in-water emulsion composition according to one embodiment of the present invention may be an oil-in-water emulsion composition comprising, for example, an oily component containing (a1) cholesterol, (a2) a higher alcohol, and (a3) ​​a hydrocarbon, a polyoxyethylene alkyl ether having a number average number of added moles of oxyethylene groups of (b1-1) 10 to 30, and an aqueous component, wherein the content of component (a1) is 0.7 to 14% by mass of the total mass of the oily component, and the content of component (b1-1) is 0.6 to 2.8% by mass of the total mass of the emulsion composition. 【0032】 [(b) Any other surfactant] The oil-in-water emulsion composition of the present invention may contain any other surfactant (surfactants other than polyoxyethylene alkyl ether) in addition to the polyoxyethylene alkyl ether described above. Any other surfactants used in the present invention are not particularly limited, but may include, for example, alkyl ether surfactants other than polyoxyethylene alkyl ethers such as polyoxyethylene polyoxypropylene alkyl ether; polyoxyethylene fatty acid esters; sorbitan fatty acid esters such as polyoxyethylene sorbitan fatty acid esters and sorbitan monopalmitate; glycerin fatty acid esters such as polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene hydrogenated castor oil isostearate, polyoxyethylene sorbitol tetra fatty acid ester, polyoxyethylene phytosterol, lipophilic glyceryl monostearate and tetraglyceryl monostearate, polyglycerin fatty acid esters, sucrose fatty acid esters, polyethylene glycol distearate, etc., which may be used individually or in combination of two or more. Among these, it is preferable to use at least one of sorbitan monopalmitate, lipophilic glyceryl monostearate, and tetraglyceryl monostearate. 【0033】 These other surfactants may be used together with polyoxyethylene alkyl ethers for emulsifying oil-in-water emulsion compositions. 【0034】 In one embodiment, the oil-in-water emulsion composition contains sorbitan fatty acid esters in addition to the polyoxyethylene alkyl ether. The content of sorbitan fatty acid esters is not particularly limited, but for example, from the viewpoint of stability or safety, 0 to 1.5% by mass of the total mass of the emulsion composition is preferred. 【0035】 In one embodiment, the oil-in-water emulsion composition contains glycerin fatty acid esters in addition to the polyoxyethylene alkyl ether. The content of glycerin fatty acid esters is not particularly limited, but for example, from the viewpoint of stability or safety, 0 to 1% by mass of the total mass of the emulsion composition is preferred. 【0036】 The content of other surfactants is not particularly limited, but from the viewpoints of stability and safety, it is preferably 0 to 7% by mass, more preferably 0.1 to 5% by mass, based on the total mass of the emulsion composition. 【0037】 <C Aqueous component (aqueous phase additive component)> In the oil-in-water emulsion composition of the present invention, as the aqueous component (aqueous phase additive component, component B) used in the aqueous phase, it may contain water. Water is contained for the purpose of forming an oil-in-water emulsion composition, and it is not particularly limited as long as it is generally used in cosmetics. For example, tap water, ion-exchanged water, distilled water, purified water, etc. can be used. 【0038】 The content of water is not particularly limited, but from the viewpoint of stability, it is preferably 50 to 95% by mass, more preferably 60 to 90% by mass, still more preferably 65 to 90% by mass, based on the total mass of the emulsion composition. 【0039】 In the oil-in-water emulsion composition, as the aqueous component, in addition to water, for example, the following components can be used. A humectant may be used as the aqueous component of the present invention. The humectant used in the present invention is not particularly limited, but for example, polyhydric alcohols such as propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butylene glycol, isopentyldiol, pentylene glycol, hexanediol, caprylyl glycol, glycerin, diglycerin, polyglycerin, polyethylene glycol, polyoxyethylene methyl glucoside, saccharides such as sorbitol, mannitol, glucose, xylitol, maltitol, trehalose, amino acids such as arginine, proline, serine, lysine HCl, threonine, valine, leucine, histidine, alanine, glycine, carnosine, sodium pyrrolidone carboxylate, betaine, urea, sodium lactate, plant extracts, seaweed extracts, etc. can be used. 【0040】 In addition, the aqueous component of the present invention may be, but is not particularly limited, a natural polymer such as guar gum, carrageenan, xanthan gum, sodium hyaluronate, pullulan, agar, or alginate, or a synthetic polymer such as hydroxyethylcellulose, hydroxymethylcellulose, carboxyvinyl polymer, polyacrylate, polyvinyl alcohol, or acrylic acid / alkyl methacrylate copolymer, or a preservative. 【0041】 In addition, raw materials may be selected as needed to create an oil-in-water emulsion composition. The oil-in-water emulsion composition of the present invention may contain, in addition to the above components, any components commonly found in cosmetics, quasi-drugs, or pharmaceuticals. For example, humectants, antioxidants, UV absorbers, thickeners, pH adjusters, powder components, chelating agents, colorants, various skin nutrients and pharmaceuticals may be included as needed. 【0042】 The oil-in-water emulsion composition of the present invention can be manufactured according to a standard method. For example, an emulsion can be produced by stirring and mixing an oily component containing (a1) cholesterol, (a2) higher alcohols, and (a3) ​​hydrocarbons, a surfactant containing (b1) polyoxyethylene alkyl ether, and an aqueous component such as water in an appropriate order. For example, as will be explained in the following example, the oil phase containing components A and B (the oil phase additive component) and the aqueous phase containing component C (the aqueous component) are heated and uniformly dissolved. Then, the oil phase containing components A and B is added to the aqueous phase of component C and emulsified using an emulsifier. After emulsification, a pH adjusting agent such as an aqueous sodium hydroxide solution is added and uniformly mixed, and then cooled to produce an emulsion. 【0043】 The oil-in-water emulsion composition of the present invention can be in various dosage forms. Specifically, it can be implemented in various dosage forms such as liquid, gel, paste, cream, and solid. 【0044】 The oil-in-water emulsion composition of the present invention can be used as a cosmetic for various purposes. Examples include skincare cosmetics such as lotions, emulsions, creams, serums, massage creams, packs, hand creams, body lotions, body creams, and sunscreens; finishing cosmetics such as foundations, eyeshadows, eyeliners, mascaras, eyebrow products, concealers, lipsticks, and lip balms; and hair cosmetics such as hair mists, treatments, and hair creams. Methods of use include application by hand, fingers, or cotton, or by impregnation into nonwoven fabrics, etc. 【0045】 The oil-in-water emulsion composition of the present invention is also suitably used in quasi-drugs, pharmaceuticals, and the like. For example, the oil-in-water emulsion composition of the present invention can also be used as a topical skin preparation. Examples include topical liquids, topical gels, creams, ointments, liniments, lotions, poultices, plasters, sprays, aerosols, etc. The method of use can be the same as that of the cosmetics described above. 【0046】 The oil-in-water emulsion composition of the present invention exhibits excellent storage stability. Preferably, the oil-in-water emulsion composition has long-term storage stability. In one embodiment, the oil-in-water emulsion composition exhibits excellent low-temperature stability, room-temperature stability, and high-temperature stability. In one embodiment, the oil-in-water emulsion composition exhibits suppressed solute precipitation and surface precipitation after storage at low temperatures (e.g., 10°C or below, particularly 5°C) for a period of, for example, one week or more, one month or more, or two months or more. Precipitation refers to a state in which solids (solutes) precipitate from the entire emulsion composition, which can be confirmed by observation using a microscope. Surface precipitation refers to a state in which solids (solutes) precipitate on the surface of the emulsion, which can be confirmed by visual inspection. In one embodiment, the oil-in-water emulsion composition exhibits a viscosity change of 10% or less after storage at low temperatures (e.g., 10°C or below, particularly 5°C) for a period of, for example, one week or more, one month or more, or two months or more. In one embodiment, the oil-in-water emulsion composition exhibits a viscosity change of 10% or less after being stored at room temperature (e.g., 20-30°C, particularly 25°C) for a period of, for example, one week or more. In another embodiment, the oil-in-water emulsion composition exhibits suppressed or prevented phase separation after being stored at high temperatures (e.g., 40°C or higher, particularly 50°C) for a period of, for example, one week or more, or one month or more, or two months or more. [Examples] 【0047】 The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. It is not limited to that. Note that the amounts and content of each component in the table are converted to pure content and are expressed in "mass %" unless otherwise specified. 【0048】 <Preparation of Oil-in-Water Emulsifier Composition> [Examples 1-18, Comparative Examples 1-14] The following components were mixed as oil phase additives (oil component A and surfactant B) to obtain the compositions shown in Tables 1 to 8, and the oil component solutions were prepared by heating and dissolving them at 80-90°C. 【0049】 (Surfactant B) (b1-1) Polyoxyethylene (EO20) behenyl ether (component (b1)) (HLB value 16.5, measured experimentally) (b1-2) Polyoxyethylene (EO2) stearyl ether ((b1) component) (HLB value 4, calculated by Oda method) (b2-1) Glycerin fatty acid ester ((b2) component) (b2-2) Polyoxyethylene (EO20) Sorbitan Coconut Oil Fatty Acid (b2) component) (b2-3) Polyoxyethylene (EO20) polyoxypropylene (PO4) cetyl ether (component (b2)) (b2-4) Polyethylene glycol monostearate (E.0.40) ((b2) component) (b2-5) Polyoxyethylene (EO100) hydrogenated castor oil ((b2) component) (b2-6) Sorbitan monopalmitate ((b2) ingredient) (b2-7) Lipophilic glyceryl monostearate ((b2) component) (b2-8) Polyethylene glycol distearate (EO4) ((b2) component) (b2-9) Polyoxyethylene (EO5) hydrogenated castor oil isostearate ((b2) component) (b2-10) Polyoxyethylene (EO5) hydrogenated castor oil ((b2) component) (b2-11) Tetraglyceryl monostearate ((b2) component) (Oily component A) (a1) Cholesterol (component (a1), solid at 25°C) (a2-1) Behenyl alcohol (component (a2), solid at 25°C) (a3-1) α-olefin oligomer (component (a3), liquid at 25°C) (a4-1)2-Cetyl ethylhexanoate (component (a4), liquid at 25°C) 【0050】 Furthermore, the following components were mixed as aqueous phase additives (aqueous component C) to achieve the composition shown in Table 1, and the aqueous component solution C was prepared by heating and dissolving them at 80-90°C. 【0051】 (Aqueous component C) (c1) Acrylic acid / alkyl methacrylate copolymer (synthetic polymer) (c2) Glycerin (humectant) (c3) 1,3-Butylene glycol (wetting agent) (c4) Preservatives (c5) Purified water 【0052】 Then, the oil-based component solution was gradually added to the aqueous component solution C while stirring, and the mixture was stirred using an emulsifier. After emulsification, an aqueous solution of (c6) sodium hydroxide (1% by mass) was added as a pH adjuster, and the mixture was homogenized. The mixture was then cooled to produce an emulsion, thereby obtaining an oil-in-water emulsion composition. 【0053】 The oil-in-water emulsion compositions prepared in the above examples and comparative examples were subjected to storage tests as follows, and the results are summarized in Tables 1 to 8. <Evaluation of storage stability of oil-in-water emulsion compositions: Storage test> (i) Low temperature stability The oil-in-water emulsion compositions prepared in the above examples and comparative examples were allowed to stand for 2 months at 5°C. The following items were evaluated for the oil-in-water emulsion compositions after standing. 【0054】 (Viscosity change) The viscosity of the oil-in-water emulsion composition was measured before (initial) and after standing, and the viscosity increase rate from the initial state was calculated and evaluated based on the following index. A viscometer TVB25L (manufactured by Toki Sangyo Co., Ltd.) was used for viscosity measurement, and the viscosity value was measured after 1 minute at 12 rpm with rotor No. 3. ○: Viscosity increase rate is less than 10% △: Viscosity increase rate is 10% or more but less than 30% ×: Viscosity increase rate is 30% or more 【0055】 (Surface precipitation) The appearance of the oil-in-water emulsion composition was visually observed before (initial) and after standing, and evaluated based on the following indicators. ◎: No surface precipitation ○: Very slight surface precipitation present △: Slight surface precipitation present ×: Clear surface precipitation present 【0056】 (precipitation) The oil-in-water emulsion compositions before (initial) and after standing were observed using a digital microscope (VHX-1000, Keyence) under polarized light and evaluated based on the following indicators. ○: No precipitation △: Slight precipitation present ×: Clear precipitation present 【0057】 The smaller the viscosity change, and the less surface precipitation or precipitation is observed, or the smaller the amount of precipitation, the more suppressed crystallization is, and the better the low-temperature stability. 【0058】 (ii) Room temperature stability The oil-in-water emulsion compositions prepared in the above examples and comparative examples were left to stand for one week at 25°C and 60% humidity. (Viscosity change) The viscosity of the oil-in-water emulsion composition was measured before (initial) and after standing, and the viscosity decrease rate from the initial state was calculated and evaluated based on the following index. A viscometer TVB25L (manufactured by Toki Sangyo Co., Ltd.) was used for viscosity measurement, and the viscosity value was measured after 1 minute at 12 rpm with rotor No. 3. ○: Viscosity reduction rate is less than 10% △: Viscosity reduction rate is 10% or more but less than 30% ×: Viscosity reduction rate of 30% or more 【0059】 (iii) High temperature stability The oil-in-water emulsion compositions prepared in the above examples and comparative examples were left to stand for 2 months at 50°C. (phase separation) The appearance of the oil-in-water emulsion composition was visually observed before (initial) and after standing, and evaluated based on the following indicators. ○: No phase separation ×: Phase separation occurs 【0060】 [Table 1] 【0061】 [Table 2] 【0062】 [Table 3] 【0063】 [Table 4] 【0064】 [Table 5] 【0065】 [Table 6] 【0066】 [Table 7] 【0067】 [Table 8] 【0068】 Tables 1-8 show that the emulsified compositions of Examples 1-18, which are formulated with a specific amount of cholesterol (a1) together with a higher alcohol (a2), a hydrocarbon (a3), and a specific amount of polyoxyethylene alkyl ether (b1), exhibit good storage stability, including suppression of precipitation and surface precipitation at low temperatures (suppression of crystallization), suppression of viscosity changes at low temperatures, suppression of viscosity changes at room temperature, and suppression of phase separation at high temperatures. 【0069】 Tables 1-2 show that when polyoxyethylene alkyl ether (component (b1)) was not present (Comparative Examples 1-5), when the content of component (b1) was low (Comparative Examples 6-7), and when the content of component (b1) was high (Comparative Example 8), precipitation (crystallization) at low temperatures, viscosity changes at low temperatures, and / or phase separation at high temperatures were observed, indicating poor low-temperature and high-temperature stability. 【0070】 As shown in Table 5, when cholesterol was included but component (b1) was not included (Comparative Examples 12-14), viscosity changes at low temperatures and phase separation at high temperatures occurred even when the cholesterol content was reduced. As shown in Table 3, when the higher alcohol (component (a2)) was not included (Comparative Example 9), phase separation at high temperatures was observed, confirming poor high-temperature stability. As shown in Table 4, the case without hydrocarbons (component (a3)) (Comparative Example 10) exhibited poor stability at room temperature. 【0071】 As shown in Table 4, Examples 1 (X1=27% by mass) and 8 (X1=22% by mass), in which the ratio (X1) of hydrocarbons (component (a3)) to the total mass of liquid oily components at 25°C contained in the emulsion composition was in the range of 15 to 40% by mass, showed superior room temperature stability (viscosity change due to storage at room temperature) compared with Example 7 (X1=11% by mass), in which the ratio was less than 20% by mass. They also showed superior low-temperature stability (surface precipitation due to storage at low temperatures) compared with Examples 9 (X1=55% by mass), 10 (X1=76% by mass), and 11 (X1=100% by mass), in which the ratio exceeded 50% by mass. As shown in Tables 6 and 7, emulsion compositions with excellent stability were obtained even when two types of polyoxyethylene alkyl ethers were used (Example 12) or when the type of surfactant combined with the polyoxyethylene alkyl ether was changed (Examples 13-16). As shown in Table 8, even when the cholesterol content was changed to various values ​​(Examples 17 and 18), an emulsified composition with excellent stability was obtained. 【0072】 Although preferred embodiments and examples of the present invention have been described above, the present invention is not limited thereto. Additions, omissions, substitutions, and other modifications to the configuration are possible without departing from the spirit of the present invention. All documents and publications mentioned herein, regardless of their purpose, are incorporated herein by reference in their entirety. This specification also includes the claims and disclosures of Japanese Patent Application No. 2020-078175 (filed April 27, 2020), which forms the basis of this application's priority claim. [Industrial applicability] 【0073】 The oil-in-water emulsion composition of the present invention has excellent storage stability despite containing cholesterol, and can be suitably used, for example, as a cosmetic or topical skin preparation.

Claims

[Claim 1] (a1) an oily component containing cholesterol, (a2) a higher alcohol having an alkyl group with 12 to 24 carbon atoms, and (a3) ​​a hydrocarbon, (b1) a surfactant containing a polyoxyethylene alkyl ether, and an aqueous component. The aforementioned component (b1) includes a polyoxyethylene alkyl ether having an HLB value of 10 to 20. The content of component (a1) is 3 to 9% by mass of the total mass of the oily components. The content of component (a2) is 0.2 to 6.5% by mass of the total mass of the oily components. The aforementioned component (a3) ​​is a hydrocarbon that is liquid at 25°C and is 10% by mass or more of the total mass of the oily components that are liquid at 25°C contained in the emulsion composition. An oil-in-water emulsion composition wherein the content of component (b1) is 0.6 to 2.8% by mass of the total mass of the emulsion composition. [Claim 2] The emulsified composition according to claim 1, wherein the content of component (b1) is 0.7 to 2.5% by mass of the total mass of the emulsified composition. [Claim 3] The emulsifying composition according to claim 1 or 2, wherein the (b1) component has an alkyl group having 12 to 24 carbon atoms. [Claim 4] The emulsifying composition according to any one of claims 1 to 3, wherein the (b1) component is one or more compounds selected from the group consisting of polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene stearyl ether, and polyoxyethylene behenyl ether. [Claim 5] The emulsifying composition according to any one of claims 1 to 4, wherein the component (a3) ​​is an α-olefin oligomer. [Claim 6] The emulsified composition according to any one of claims 1 to 5, wherein the content of component (a1) is in the range of 0.3 to 1.5% by mass of the total mass of the emulsified composition. [Claim 7] The emulsified composition according to any one of claims 1 to 6, wherein the content of component (a3) ​​is 10% by mass or more of the total mass of the oily components. [Claim 8] The emulsified composition according to any one of claims 1 to 7, wherein the component (a3) ​​is in the range of 10 to 60% by mass of the total mass of the oily component that is liquid at 25°C contained in the emulsified composition. [Claim 9] The emulsified composition according to any one of claims 1 to 8, wherein the oily component that is liquid at 25°C is a hydrocarbon and an ester oil that are liquid at 25°C. [Claim 10] The emulsified composition according to any one of claims 1 to 9, wherein the content of the oily component is in the range of 7 to 45% by mass of the total mass of the emulsified composition. [Claim 11] The emulsified composition according to any one of claims 1 to 10, wherein the content of the oily component that is liquid at 25°C is in the range of 5 to 40% by mass of the total mass of the emulsified composition. [Claim 12] The emulsifying composition according to any one of claims 1 to 11, wherein component (b1) is a polyoxyethylene alkyl ether having a number average number of added moles of oxyethylene groups of 10 to 30. [Claim 13] (a1) an oily component comprising cholesterol, (a2) a higher alcohol having an alkyl group with 12 to 24 carbon atoms, and (a3) ​​a hydrocarbon, (b1-1) a polyoxyethylene alkyl ether having a number average number of added moles of oxyethylene groups of 10 to 30, and an aqueous component. The content of component (a1) is 3 to 9% by mass of the total mass of the oily components. The content of component (a2) is 0.2 to 6.5% by mass of the total mass of the oily components. The aforementioned component (a3) ​​is a hydrocarbon that is liquid at 25°C and is 10% by mass or more of the total mass of the oily components that are liquid at 25°C contained in the emulsion composition. An oil-in-water emulsion composition in which the content of component (b1-1) is 0.6 to 2.8% by mass of the total mass of the emulsion composition. [Claim 14] An emulsified composition according to any one of claims 1 to 13, which is a cosmetic. [Claim 15] An emulsified composition according to any one of claims 1 to 13, which is a topical skin preparation.

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