Gel-like oil-in-water emulsion

Abstract

To provide a gelatinous oil-in-water emulsion composition that is excellent in initial hardness and temporal stability of hardness.SOLUTION: A gelatinous oil-in-water emulsion composition contains: a neutral amino acid; an oil that is liquid at 25°C, of 15 mass% or more relative to the total mass of the gelatinous oil-in-water emulsion composition; a nonionic emulsifier of 5 mass% or more relative to the total mass of the gelatinous oil-in-water emulsion composition; an anionic emulsifier; and water.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a gelled oil-in-water emulsion composition. [Background technology]

[0002] 2. Description of the Related Art In the field of cosmetics, gel-like oil-in-water emulsion compositions are used for the purposes of improving the feel when cosmetics are applied to the skin and preventing dripping.

[0003] In recent years, cosmetics are required to have various sensations when used. For example, when a gel-type oil-in-water emulsion composition containing an anionic emulsifier is applied to the skin, the electrostatic repulsion between the emulsified particles in the gel-type oil-in-water emulsion composition is reduced by the salt present on the skin, and the gel structure is destroyed, so that the gel-type oil-in-water emulsion composition can have a melting sensation when used.

[0004] As a gel-like oil-in-water emulsion composition, Patent Document 1 proposes a gel-like oil-in-water emulsion composition containing liquid oil, a nonionic emulsifier, an anionic emulsifier, and water. Moreover, Patent Document 2 proposes an oil-in-water emulsion containing liquid oil, an anionic emulsifier, and water. Furthermore, Patent Documents 3 and 4 propose oil-in-water emulsion compositions containing a neutral amino acid, liquid oil, a nonionic emulsifier, an anionic emulsifier, and water. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-105766 A [Patent Document 2] JP 2008-137956 A [Patent Document 3] JP 2006-290762 A [Patent Document 4] JP 2019-142825 A Summary of the Invention [Problem to be solved by the invention]

[0006] When an anionic emulsifier is used, the emulsion particles contained in the gel-like oil-in-water emulsion composition have low stability and may coalesce over time. In addition, the coalescence of the emulsion particles over time may reduce the hardness of the gel-like oil-in-water emulsion composition, making it impossible to maintain the gel structure.

[0007] In addition, nicotinamide is sometimes used for the purpose of whitening effects, etc., but the use of nicotinamide reduces the hardness of the gelled oil-in-water emulsion composition immediately after production (hereinafter referred to as initial hardness), and the hardness tends to decrease over time, making it more difficult to maintain the gel structure.

[0008] The gel-like oil-in-water emulsion composition proposed in Patent Document 1 and the oil-in-water emulsion proposed in Patent Document 2 have the risk of decreasing in hardness over time, making it difficult to maintain the gel structure. The oil-in-water emulsion compositions proposed in Patent Documents 3 and 4 do not have sufficient initial hardness, and the hardness decreases over time, and there is a risk that the gel structure cannot be maintained.

[0009] The present disclosure has been made in consideration of the above circumstances, and an object of the present disclosure is to provide a gel-like oil-in-water emulsion composition that is excellent in initial hardness and can suppress a decrease in hardness over time. [Means for solving the problem]

[0010] <1> The gel-like oil-in-water emulsion composition comprises a neutral amino acid, an oil that is liquid at 25°C in an amount of 15% by mass or more based on the total mass of the gel-like oil-in-water emulsion composition, a nonionic emulsifier in an amount of 5% by mass or more based on the total mass of the gel-like oil-in-water emulsion composition, an anionic emulsifier, and water. <2> The content of the oil relative to the total mass of the gel-like oil-in-water emulsion composition is 20% by mass or more. <1> 2. A gel-like oil-in-water emulsion composition according to claim 1 . <3> The content of the oil relative to the total mass of the gel-like oil-in-water emulsion composition is 29% by mass or less. <1> or <2> 2. A gel-like oil-in-water emulsion composition according to claim 1 . <4> The neutral amino acid is at least one selected from the group consisting of glycine, alanine, leucine, isoleucine, and tranexamic acid. <1> ~ <3> 10. The gel-like oil-in-water emulsion composition according to claim 9 . <5> Cosmetics <1> ~ <4> 10. The gel-like oil-in-water emulsion composition according to claim 9 . Effect of the Invention

[0011] According to the present disclosure, it is possible to provide a gel-like oil-in-water emulsion composition that is excellent in initial hardness and can suppress a decrease in hardness over time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments for carrying out the present disclosure will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the components are not essential unless specifically stated otherwise. The same applies to the numerical values ​​and their ranges, and they do not limit the present disclosure.

[0013] In the present disclosure, a numerical range indicated using "~" includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.

[0014] In the present disclosure, each component may contain multiple types of corresponding substances. When multiple substances corresponding to each component are present in the composition, the content of each component means the total content of the multiple substances present in the composition, unless otherwise specified.

[0015] In the present disclosure, the "gel-like oil-in-water emulsion composition" refers to a composition in which an oil phase (emulsion particles), which is a dispersed phase, is present in an aqueous phase that constitutes a continuous phase, and which does not exhibit fluidity and retains its shape at 25°C in the absence of applied stress.

[0016] In the present disclosure, "neutral amino acid" refers to an amino acid that contains the same number of acidic carboxyl groups and basic amino groups in the molecule. The neutral amino acids may be D- or L-isomers, or a mixture of these. In addition, neutral amino acids include not only proteinogenic amino acids but also non-proteinogenic amino acids.

[0017] In this disclosure, the "oil" in the oil that is liquid at 25°C means an oily component that has the property of dissolving in an amount of less than 0.1 g in 100 g of water at a liquid temperature of 20°C.

[0018] (Gel-like oil-in-water emulsion composition) The gel-like oil-in-water emulsion composition of the present disclosure comprises a neutral amino acid, an oil that is liquid at 25°C in an amount of 15% by mass or more, based on the total mass of the gel-like oil-in-water emulsion composition, a nonionic emulsifier in an amount of 5% by mass or more, based on the total mass of the gel-like oil-in-water emulsion composition, an anionic emulsifier, and water.

[0019] According to the oil-in-water gel emulsion composition of the present disclosure, it is possible to provide a gel oil-in-water emulsion composition that is excellent in initial hardness and is capable of suppressing a decrease in hardness over time. Hereinafter, the ability to inhibit the decrease in hardness over time is also referred to as temporal stability of hardness.

[0020] The reason why the above effect is achieved is presumed to be as follows, but is not limited to this. The gel-like oil-in-water emulsion composition of the present disclosure contains a neutral amino acid, which is presumably responsible for stabilizing the interface between the emulsion particles (also referred to as oil particles) and the aqueous phase, thereby improving the initial hardness of the gel-like oil-in-water emulsion composition and inhibiting a decrease in hardness over time. In addition, the gel-like oil-in-water emulsion composition of the present disclosure contains 15% by mass or more of oil that is liquid at 25°C, based on the total mass of the gel-like oil-in-water emulsion composition. This increases the total volume of the emulsion particles and enhances the interaction between the emulsion particles, which is presumably why the initial hardness of the gel-like oil-in-water emulsion composition is improved and the decrease in hardness over time can be inhibited. Furthermore, the gel-like oil-in-water emulsion composition of the present disclosure contains 5 mass % or more of a nonionic emulsifier, based on the total mass of the gel-like oil-in-water emulsion composition. As a result, it is presumed that the more emulsifier there is, the larger the total surface area of ​​the emulsion particles becomes, and the greater the interaction between the emulsion particles becomes, thereby improving the initial hardness of the gel-like oil-in-water emulsion composition and suppressing a decrease in hardness over time.

[0021] From the viewpoint of the stability of the gel structure, the hardness of the gelled oil-in-water emulsion composition of the present disclosure more than 24 hours after production is preferably 15 g or more and 150 g or less, more preferably 20 g or more and 120 g or less, and even more preferably 40 g or more and 100 g or less. In addition, taking into consideration that hardness decreases over time, the hardness of the gelled oil-in-water emulsion composition of the present disclosure immediately after production (within 24 hours after production) is preferably 50 g or more and 150 g or less, more preferably 55 g or more and 120 g or less, and even more preferably 60 g or more and 100 g or less. It should be noted that the time elapsed from the production of the gelled oil-in-water emulsion composition does not include the storage time in a container described below. In the present disclosure, hardness is measured as follows. First, 100 g of the measurement object is placed in a glass container having a diameter of 47 mm and a height of 90 mm, capped, and stored at room temperature (for example, 25° C.) for 24 hours. Next, the hardness of the measurement object is measured using a viscoelasticity measuring device (a so-called rheometer) while it is placed in the glass container. Specifically, the tip of a 20 mm diameter adapter is inserted 20 mm into the measurement object with a load of 200 g at a speed of 60 mm / min in an environment with an ambient temperature of 25°C, and the peak stress value measured at the time of insertion is taken as the measured hardness value (unit: g). The rheometer is not particularly limited, but for example, FUDOH REHOMETER manufactured by Rheotec Co., Ltd. can be suitably used.

[0022] From the viewpoint of transparency, the average particle size of the emulsified particles contained in the gel-like oil-in-water emulsion composition of the present disclosure is preferably 20 nm to 200 nm, more preferably 30 nm to 150 nm, even more preferably 40 nm to 100 nm, and particularly preferably 50 nm to 80 nm. In the present disclosure, the term "average particle size" refers to the volume average particle size determined by dynamic light scattering. Examples of dynamic light scattering particle size measuring instruments include the Concentrated System Particle Size Analyzer FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.), Nanotrack UPA (manufactured by Nikkiso Co., Ltd.), and Dynamic Light Scattering Particle Size Distribution Measuring Instrument LB-550 (manufactured by Horiba, Ltd.). The average particle size is measured at 25°C after diluting the gelled oil-in-water emulsion composition 100 times by mass with pure water. The "pure water" used herein is pure water obtained using an ultrapure water production apparatus manufactured by Merck Ltd.

[0023] (Neutral Amino Acids) Examples of neutral amino acids include α-amino acids, β-amino acids, γ-amino acids, δ-amino acids, and ε-amino acids. Examples of α-amino acids include glycine, alanine, leucine, isoleucine, phenylalanine, cysteine, methionine, tyrosine, valine, threonine, serine, proline, tryptophan, asparagine, and glutamine. Examples of β-amino acids include β-alanine. Examples of γ-amino acids include γ-aminobutyric acid. Examples of δ-amino acids include δ-aminovaleric acid. Examples of ε-amino acids include tranexamic acid.

[0024] From the viewpoint of initial hardness and stability of hardness over time, among the neutral amino acids described above, at least one of α-amino acids and ε-amino acids is preferred, at least one selected from the group consisting of glycine, alanine, leucine, isoleucine, and tranexamic acid is more preferred, and at least one selected from the group consisting of glycine, alanine, and tranexamic acid is even more preferred.

[0025] From the viewpoint of the initial hardness and the stability of hardness over time, the content of the neutral amino acid relative to the total mass of the gelled oil-in-water emulsion composition is preferably 0.5% by mass to 10% by mass, more preferably 0.7% by mass to 7.5% by mass, even more preferably 0.8% by mass to 5% by mass, and particularly preferably 1% by mass to 3% by mass. Furthermore, by adjusting the content of the neutral amino acid relative to the total mass of the gelled oil-in-water emulsion composition to fall within the above range, stickiness can be suppressed.

[0026] (liquid oil at 25℃) From the viewpoint of suppressing stickiness, it is preferable to use one or more oils selected from the group consisting of hydrocarbon oils and silicone oils as the oil that is liquid at 25° C. and is contained in the gel-like oil-in-water emulsion composition of the present disclosure. Also, from the viewpoint of suppressing stickiness, it is preferable to use a combination of a hydrocarbon oil and a silicone oil.

[0027] Examples of the hydrocarbon oil include squalane, liquid paraffin, hydrogenated polyisobutene, cyclohexane, etc. Among the above, squalane is preferred from the viewpoint of moisturizing properties.

[0028] The silicone oil is not particularly limited as long as it contains a siloxane structure and is liquid at 25°C. Examples of silicone oils include dimethicone, trisiloxane, cyclomethicone, cyclopentasiloxane, methyl trimethicone, caprylyl methicone, phenyl trimethicone, diphenyl dimethicone, diphenylsiloxyphenyl trimethicone, etc. Among the above, at least one selected from the group consisting of dimethicone, methyl trimethicone, caprylyl methicone, and cyclopentasiloxane is preferred because it is less sticky and has a good feel when used.

[0029] The viscosity of the oil that is liquid at 25° C. is not particularly limited, but may be 0.1 mPa·s to 10,000 mPa·s, or may be 1 mPa·s to 1,000 mPa·s. In this disclosure, the viscosity of oil that is liquid at 25° C. is measured at 25° C. and 1 atmospheric pressure using a rotational viscometer (for example, product name "VISCOMETER TV-22" manufactured by Toki Sangyo Co., Ltd.).

[0030] From the viewpoint of initial hardness and stability of hardness over time, the content of oil that is liquid at 25°C relative to the total mass of the gelled oil-in-water emulsion composition is preferably 18 mass% or more, and more preferably 20 mass% or more. From the viewpoint of suppressing stickiness, the content of oil that is liquid at 25°C relative to the total mass of the gelled oil-in-water emulsion composition is preferably 30% by mass or less, more preferably 29% by mass or less, even more preferably 27% by mass or less, and particularly preferably 25% by mass or less. Furthermore, by making the content of oil that is liquid at 25°C relative to the total mass of the gelled oil-in-water emulsion composition 30% by mass or less, emulsification treatment under high pressure conditions can be carried out well.

[0031] When a hydrocarbon oil and a silicone oil are used in combination, from the viewpoint of hardness and stability of hardness over time, the ratio of the hydrocarbon oil content to the silicone oil content (hydrocarbon oil content / silicone oil content) is preferably 0.1 to 10, and more preferably 0.3 to 3.

[0032] (Nonionic emulsifier) Examples of the nonionic emulsifier include fatty acid esters, polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenol ethers, polyoxyethylene sorbitan alkyl esters, etc. From the viewpoint of hardness and stability of hardness over time, fatty acid esters are preferred among the above nonionic emulsifiers. Examples of fatty acid esters include fatty acid sucrose, fatty acid glyceryl, fatty acid polyglyceryl, and the like. Examples of fatty acid sucrose include sucrose stearate, sucrose distearate, sucrose tristearate, sucrose tetrastearate, sucrose laurate, sucrose dilaurate, sucrose trilaurate, sucrose tetralaurate, sucrose palmitate, sucrose dipalmitate, sucrose tripalmitate, sucrose tetrapalmitate, sucrose myristate, sucrose dimyristate, sucrose trimyristate, and sucrose tetramyristate. Examples of fatty acid glyceryl include glyceryl stearate, glyceryl myristate, glyceryl oleate, and glyceryl isostearate. Examples of fatty acid polyglyceryl include polyglyceryl-5 oleate, polyglyceryl-10 laurate, polyglyceryl-10 oleate, and polyglyceryl-10 palmitate.

[0033] From the viewpoints of initial hardness, stability of hardness over time, and suppression of stickiness, the content of the nonionic emulsifier relative to the total mass of the gelled oil-in-water emulsion composition is preferably 5.2% by mass to 10% by mass, more preferably 5.4% by mass to 8% by mass, and even more preferably 5.6% by mass to 7% by mass.

[0034] (anionic emulsifier) Examples of the anionic emulsifier include glutamic acid salts, fatty acid salts having 12 to 24 carbon atoms, alkyl sulfates, alkyl ether sulfates, alkyl phosphates, etc. Among the above, glutamic acid salts are preferred from the viewpoints of initial hardness and stability of hardness over time.

[0035] Examples of glutamic acid salts include acyl glutamic acid salts and sodium surfactin. From the viewpoint of initial hardness and stability of hardness over time, acyl glutamic acid salts are preferred.

[0036] Examples of acyl glutamate include sodium cocoyl glutamate, disodium cocoyl glutamate, potassium cocoyl glutamate, triethanolamine cocoyl glutamate, sodium N-lauroyl-L-glutamate, disodium N-lauroyl-L-glutamate, potassium N-lauroyl-L-glutamate, triethanolamine N-lauroyl-L-glutamate, sodium N-myristoyl-L-glutamate, potassium N-myristoyl-L-glutamate, sodium stearoyl glutamate, potassium N-stearoyl-L-glutamate, sodium palm fatty acid glutamate, and sodium dilauroyl glutamate lysine. Among the above, sodium stearoyl glutamate is preferred from the viewpoint of stability over time. Examples of sodium stearoyl glutamate include sodium N-stearoyl-L-glutamate and disodium N-stearoyl-L-glutamate.

[0037] From the viewpoint of initial hardness and stability of hardness over time, the content of the anionic emulsifier relative to the total mass of the gelled oil-in-water emulsion composition is preferably 0.1 to 5% by mass, and more preferably 0.3 to 3% by mass.

[0038] (water) Examples of water include ion-exchanged water, pure water, purified water, tap water, etc., and among these, purified water is preferred in terms of its applicability to cosmetics.

[0039] The content of water relative to the total mass of the gelled oil-in-water emulsion composition is not particularly limited, and can be 30% by mass to 70% by mass.

[0040] (Cholesterol and Phytosterols) From the viewpoint of initial hardness and stability of hardness over time, it is preferable that the gel-like oil-in-water emulsion composition of the present disclosure further contains at least one of cholesterol and phytosterol. In the present disclosure, "cholesterol" is a general term for sterol compounds contained in animals, and "phytosterol" is a general term for sterol compounds contained in plants. In addition, in the present disclosure, "cholesterol" and "phytosterol" include their derivatives.

[0041] Examples of cholesterol include cholesterol, dihydrocholesterol, dehydrocholesterol, cholesteryl oleate, cholesteryl isostearate, cholesteryl hydroxystearate, polyoxyethylene cholesteryl ether, and the like.

[0042] The phytosterol is preferably a phytosterol polyglyceryl ether, more preferably a polyoxyethylene phytosterol. Examples of phytosterols include sitosterol, stigmasterol, fucosterol, spinasterol, and brassicasterol.

[0043] Among the above, from the viewpoints of initial hardness and stability of hardness over time, it is preferable that the gelled oil-in-water emulsion composition of the present disclosure contains polyoxyethylene phytosterol.

[0044] From the viewpoint of initial hardness and stability of hardness over time, the average number of moles of oxyethylene groups added in the polyoxyethylene phytosterol is preferably not less than 5. The average number of moles of oxyethylene groups added can be found in the catalogue.

[0045] From the viewpoint of stability over time and suppression of stickiness, the content of at least one of cholesterol and phytosterol relative to the total mass of the gelled oil-in-water emulsion composition is preferably 0.1% by mass to 10% by mass, more preferably 0.2% by mass to 5% by mass, and even more preferably 0.5% by mass to 2% by mass. In the present disclosure, the "content of at least one of cholesterol and phytosterol relative to the total mass of the gel-like oil-in-water emulsion composition" means the cholesterol content when the gel-like oil-in-water emulsion composition contains only cholesterol, means the phytosterol content when the gel-like oil-in-water emulsion composition contains only phytosterol, and means the sum of these contents when the gel-like oil-in-water emulsion composition contains cholesterol and phytosterol.

[0046] (nicotinamide) The gel-like oil-in-water emulsion composition of the present disclosure can contain nicotinamide. Nicotinamide is a water-soluble vitamin, and a gel-like oil-in-water emulsion composition containing nicotinamide has effects such as improving rough skin and whitening effects. When the gelled oil-in-water emulsion composition contains nicotinic acid amide, the initial hardness and the stability of the hardness over time of the gelled oil-in-water emulsion composition may decrease. In the present disclosure, a neutral amino acid is used, and the decrease in the initial hardness and the stability of the hardness over time of the gelled oil-in-water emulsion composition caused by the use of nicotinic acid amide can be suppressed.

[0047] From the viewpoint of initial hardness and stability of hardness over time, the content of nicotinamide relative to the total mass of the gelled oil-in-water emulsion composition is preferably 0.5% by mass to 10% by mass, more preferably 1% by mass to 7% by mass, and even more preferably 2% by mass to 6% by mass. Furthermore, by setting the content of nicotinamide within the above numerical range, stickiness of the gelled oil-in-water emulsion composition can be suppressed.

[0048] (Water-soluble moisturizer) The gel-like oil-in-water emulsion composition of the present disclosure may contain a water-soluble moisturizer. In the present disclosure, "water-soluble" means that the solubility in 100 g of water at a liquid temperature of 22°C and a pH of 7.0 is 0.1 g or more.

[0049] From the viewpoint of suppressing stickiness, the water-soluble moisturizing agent is preferably a sugar. In the present disclosure, the sugar includes derivatives. Examples of the sugar derivatives include sugars modified with an oxyethylene group.

[0050] Examples of sugars include glucose, sucrose, sorbitol, trehalose, maltose, mannitol, and maltotriose. Among the above, from the viewpoint of suppressing stickiness, at least one selected from the group consisting of sucrose, sorbitol and trehalose is preferred, and trehalose is more preferred.

[0051] From the viewpoint of suppressing stickiness, the content of the water-soluble moisturizing agent relative to the total mass of the gel-like oil-in-water emulsion composition is preferably 2% by mass to 20% by mass, more preferably 4% by mass to 15% by mass, and even more preferably 6% by mass to 13% by mass.

[0052] (others) The gel-like oil-in-water emulsion composition of the present disclosure may contain other components such as other solvents such as ethanol, fragrances, pH adjusters, pH buffers, anti-inflammatory agents, keratin softeners, blood circulation promoters, antioxidants, preservatives, chelating agents, UV absorbers, colorants, lipids other than cholesterol and phytosterols (e.g., lecithin, etc.), and carotenoids (astaxanthin, β-carotene, zeaxanthin, lycopene, lutein, etc.).

[0053] (Polymer thickener) From the viewpoint of suppressing stickiness, when the gelled oil-in-water emulsion composition of the present disclosure contains a polymeric thickener, the content of the polymeric thickener relative to the total mass of the gelled oil-in-water emulsion composition is preferably less than 1 mass %, more preferably less than 0.1 mass %, and even more preferably less than 0.01 mass %. Furthermore, it is particularly preferred that the gel-like oil-in-water emulsion composition of the present disclosure does not contain a polymer thickener.

[0054] (Application) The gel-like oil-in-water emulsion composition of the present disclosure can be used as a cosmetic. Examples of the cosmetics include skin care cosmetics (skin lotions, beauty essences, etc.), body cosmetics (body lotions, etc.), and scalp cosmetics.

[0055] The container into which the cosmetic is filled is not particularly limited, but an airless container or a shut-off airless container is preferred because it prevents the intrusion of germs from the outside air and allows the cosmetic to be used for a long period of time in a sterile state. In addition, it is preferred that the cosmetic is filled into the container by aseptic filling.

[0056] (Method of producing a gel-like oil-in-water emulsion composition) A method for producing the gel-like oil-in-water emulsion composition of the present disclosure will be described below, but is not limited thereto.

[0057] The gel-like oil-in-water emulsion composition can be produced by mixing an oil phase composition containing at least an oil that is liquid at 25°C, a nonionic emulsifier, and an anionic emulsifier with an aqueous phase composition containing at least a neutral amino acid and water, and then subjecting the mixture to an emulsification treatment.

[0058] The oil phase composition can be obtained by adding a nonionic emulsifier and an anionic emulsifier to an oil that is liquid at 25° C., and dissolving them by heating. Cholesterol, phytosterol, lipids other than cholesterol and phytosterol, carotenoids, etc. may be added to the above oil.

[0059] The aqueous phase composition can be obtained by adding a neutral amino acid to water and dissolving it by heating. Ethanol, water-soluble moisturizers, nicotinamide, preservatives, fragrances, etc. may be added to the water.

[0060] The emulsification treatment is preferably carried out under high pressure conditions, since this allows obtaining fine emulsion particles and improves the transparency of the gelled oil-in-water emulsion composition. In the emulsification treatment, the shear force applied to the mixture is preferably 100 MPa or more, more preferably 150 MPa or more, and even more preferably 200 MPa or more.

[0061] The stirring device used in the emulsification treatment under the above-mentioned high pressure conditions is not particularly limited, and examples thereof include a high-speed stirring method using a homomixer, a disper mixer, an ultra mixer, etc., an ultrasonic method using an ultrasonic homogenizer, and a high-pressure homogenizer method in which high shear force is applied by a high-pressure homogenizer.

[0062] Examples of ultrasonic homogenizers include ultrasonic homogenizers manufactured by Nippon Seiki Seisakusho Co., Ltd. (US-600, US-1200T, RUS-1200T, MUS-1200T, etc.) and ultrasonic processors manufactured by Hielscher AG (UIP2000, UIP-4000, UIP-8000, UIP-16000, etc.). These high-output ultrasonic irradiation devices are preferably used at a frequency of 25 kHz or less, more preferably 15 kHz to 20 kHz.

[0063] Examples of the high-pressure homogenizer include a chamber type high-pressure homogenizer and a homogenizing valve type high-pressure homogenizer. As a chamber type high pressure homogenizer, there is a microfluidizer (Microfluidizer) Examples of suitable ion exchangers include the Nanomizer (manufactured by Dix Co., Ltd.), Nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.), and Ultimizer (manufactured by Sugino Machine Ltd.). As a homogenous valve type high pressure homogenizer, the Gaulin type homogenizer (APV) (manufactured by Ranier Co.), high pressure homogenizer (manufactured by Niro Soabi Co., Ltd.), Examples of suitable homogenizers include a homogenizer (manufactured by Sanwa Kikai Co., Ltd.), a high pressure homogenizer (manufactured by Izumi Food Machinery Co., Ltd.), and an ultra-high pressure homogenizer (manufactured by Ika Co., Ltd.).

[0064] The produced gel-like oil-in-water emulsion composition may be subjected to a sterilization treatment. The oil phase composition and the aqueous phase composition may be subjected to a sterilization treatment. Examples of sterilization treatments include autoclave sterilization, filtration sterilization, plasma sterilization, sterilization using chemicals such as sterilizing agents, sterilization using sterilizing gases such as ethylene oxide gas, and sterilization by irradiation with radiation such as gamma rays.

[0065] All publications, patent applications, and standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, and standard was specifically and individually indicated to be incorporated by reference. EXAMPLES

[0066] The above embodiment will be specifically described below with reference to examples, but the above embodiment is not limited to these examples. Unless otherwise specified, the numerical values ​​of each component in Tables 1 and 2 indicate the content (mass%) of each component relative to the total mass of the gel-like oil-in-water emulsion composition.

[0067] <Examples 1-1 to 1-3> (Preparation of Oil Phase Composition) The nonionic emulsifier, anionic emulsifier, lecithin and astaxanthin shown in Table 1 below were added to oil that was liquid at 25°C, and then heated at 70°C for 30 minutes to dissolve, thereby obtaining an oil phase composition.

[0068] (Preparation of Aqueous Phase Composition) The neutral amino acid, water-soluble moisturizer, preservative and fragrance shown in Table 1 below were added to a mixed solvent of water and ethanol, heated at 70° C. for 45 minutes and dissolved to obtain an aqueous phase composition.

[0069] (Production of gel-like oil-in-water emulsion composition) The oily phase composition was added to the aqueous phase composition while stirring the aqueous phase composition, and a preliminary emulsion was obtained by ultrasonic treatment for 1 minute per 100 g using an ultrasonic homogenizer (US-600, manufactured by Nippon Seiki Seisakusho Co., Ltd.). The preliminary emulsion was then emulsified at a shear force of 245 MPa using an ultra-high pressure emulsifier (Ultimizer HJP-25001, manufactured by Sugino Machine Corp.) to obtain a gel-like oil-in-water emulsion composition.

[0070] <Comparative Examples 1-1 to 1-4> A gel-like oil-in-water emulsion composition was obtained in the same manner as in Example 1-1, except that no neutral amino acid was used or a basic amino acid, an acidic amino acid, or urea shown in Table 1 below was used instead of the neutral amino acid.

[0071] <Comparative Examples 1-5 to 1-6> A gel-like oil-in-water emulsion composition was obtained in the same manner as in Comparative Example 1-1, except that the content of oil that was liquid at 25°C relative to the total mass of the gel-like oil-in-water emulsion composition was less than 15 mass%, or the content of nonionic emulsifier relative to the total mass of the gel-like oil-in-water emulsion composition was less than 5 mass%.

[0072] <Examples 2-1 to 2-6> (Preparation of Oil Phase Composition) The nonionic emulsifier, anionic emulsifier, lecithin and astaxanthin shown in Table 2 below were added to oil that was liquid at 25°C, heated at 70°C for 30 minutes and dissolved to obtain an oil phase composition.

[0073] (Preparation of Aqueous Phase Composition) The neutral amino acid, nicotinamide, water-soluble moisturizer, preservative and fragrance shown in Table 1 below were added to a mixed solvent of water and ethanol, heated at 70° C. for 45 minutes and dissolved to obtain an aqueous phase composition.

[0074] (Production of gel-like oil-in-water emulsion composition) The oily phase composition was added to the aqueous phase composition while stirring the aqueous phase composition, and a preliminary emulsion was obtained by ultrasonic treatment for 1 minute per 100 g using an ultrasonic homogenizer (US-600, manufactured by Nippon Seiki Seisakusho Co., Ltd.). The preliminary emulsion was then emulsified at a shear force of 245 MPa using an ultra-high pressure emulsifier (Ultimizer HJP-25001, manufactured by Sugino Machine Corp.) to obtain a gel-like oil-in-water emulsion composition.

[0075] The details of each component in Tables 1 and 2 are as follows. Nonionic emulsifier A: Sucrose stearate Nonionic emulsifier B: Glyceryl stearate Nonionic emulsifier C: Polyglyceryl-5 oleate Anionic emulsifier: Sodium stearoyl glutamate Lecithin: H. Hosultaine, LIPOID P-75 Polyoxyethylene phytosterol: Nikkol (registered trademark) BPS-5, manufactured by Nikko Chemicals Co., Ltd. Astaxanthin: Astax-ST, manufactured by Marine Daio Co., Ltd. Oil A, which is liquid at 25℃: Dimethicone Oil B, liquid at 25℃: Cyclopentasiloxane Oil C: Squalane, which is liquid at 25℃ Neutral Amino Acid A: Glycine Neutral Amino Acid B: Alanine Neutral Amino Acid C: Tranexamic Acid Basic amino acid: Lysine · Acidic amino acid: glutamic acid Urea: Fujifilm Wako Pure Chemical Industries, Ltd. Water-soluble moisturizer: Trehalose · Preservative: Methylparaben Fragrance: Takasago International Corporation Nicotinamide: Niacinamide PC, manufactured by DSM

[0076] <<Initial hardness evaluation>> 100 g of the gel-like oil-in-water emulsion compositions obtained in the above Examples and Comparative Examples were placed in a glass container with a diameter of 47 mm and a height of 90 mm, and the container was capped. The gel-like oil-in-water emulsion compositions used were those immediately after production (within 24 hours after production). Next, the hardness of the gel-like oil-in-water emulsion composition stored at 25° C. for 24 hours was measured in the above-mentioned glass container using a viscoelasticity measuring device (FUDOH REHOMETER, manufactured by Rheotec Co., Ltd.). Specifically, for a gel-like oil-in-water emulsion composition stored at 25°C for 24 hours, the tip of an adapter having a diameter of 20 mm was inserted 20 mm into the gel at a speed of 60 mm / min under a load of 200 g in an environment with an ambient temperature of 25°C, and the peak stress value measured at the time of insertion was recorded as the initial hardness. The measured initial hardness was evaluated based on the following evaluation criteria. The evaluation results are summarized in Tables 1 and 2. The initial hardness of the gel-like oil-in-water emulsion compositions obtained in Comparative Examples 1-2 to 1-6 was less than 50 g, and no further evaluation was carried out. (Evaluation Criteria) A: The initial hardness was 70g or more. B: The initial hardness was 60 g or more and less than 70 g. C: The initial hardness was 50 g or more and less than 60 g. D: The initial hardness was less than 50 g.

[0077] <<Evaluation of hardness stability over time>> The oil-in-water emulsion compositions obtained in the above Examples and Comparative Examples were stored in an environment of 40° C. for 30 days. After storage, the hardness of the gel-like oil-in-water emulsion composition was measured in the same manner as in the above-mentioned evaluation of initial hardness. The difference between the initial hardness of the gel-like oil-in-water emulsion composition obtained in the above initial hardness evaluation and the hardness of the gel-like oil-in-water emulsion composition after storage (initial hardness of the gel-like oil-in-water emulsion composition - hardness of the gel-like oil-in-water emulsion composition after storage) was determined, and the stability of hardness over time was evaluated based on the following evaluation criteria. The evaluation results are summarized in Tables 1 and 2. (Evaluation Criteria) A: The difference in hardness was less than 6g. B: The hardness difference was 6 g or more and less than 16 g. C: The hardness difference was 16 g or more.

[0078] [Table 1]

[0079] [Table 2]

[0080] The results in Table 1 show that the gel-like oil-in-water emulsion compositions obtained in Examples 1-1 to 1-3 have superior initial hardness compared to the gel-like oil-in-water emulsion compositions obtained in Comparative Examples 1-1 to 1-4, which do not use a neutral amino acid. Furthermore, the results in Table 1 show that the gel-like oil-in-water emulsion compositions obtained in Examples 1-1 to 1-3 have superior stability of hardness over time compared to the gel-like oil-in-water emulsion composition obtained in Comparative Example 1-1, which does not use a neutral amino acid.

[0081] The results in Table 1 show that the gel-like oil-in-water emulsion compositions obtained in Examples 1-1 to 1-3 have superior initial hardness compared to the gel-like oil-in-water emulsion compositions obtained in Comparative Examples 1-5 to 1-6, in which the content of oil that is liquid at 25°C relative to the total mass of the gel-like oil-in-water emulsion composition is less than 15 mass% or the content of nonionic emulsifier relative to the total mass of the gel-like oil-in-water emulsion composition is less than 5 mass%.

[0082] Furthermore, when comparing the gel-like oil-in-water emulsion composition obtained in Comparative Example 1-1, in which no neutral amino acid was used, with the gel-like oil-in-water emulsion compositions obtained in Comparative Examples 1-5 to 1-6, in which no neutral amino acid was used and in which the content of oil that is liquid at 25°C relative to the total mass of the gel-like oil-in-water emulsion composition was less than 15 mass% or the content of nonionic emulsifier relative to the total mass of the gel-like oil-in-water emulsion composition was less than 5 mass%, it was found that the gel-like oil-in-water emulsion compositions obtained in Comparative Examples 1-5 to 1-6 were inferior in initial hardness. Furthermore, when comparing the gel-like oil-in-water emulsion composition obtained in Comparative Example 1-1, which did not use a neutral amino acid, with the gel-like oil-in-water emulsion compositions obtained in Comparative Examples 1-2 to 1-4, which used a basic amino acid, an acidic amino acid, or urea instead of a neutral amino acid, it is found that the gel-like oil-in-water emulsion compositions obtained in Comparative Examples 1-2 to 1-4 are inferior in initial hardness.

[0083] Furthermore, the results in Table 2 show that the gelled oil-in-water emulsion compositions obtained in Examples 2-1 to 2-6 have excellent initial hardness and stability of hardness over time, despite the use of nicotinamide.

Claims

1. A composition comprising at least one neutral amino acid selected from the group consisting of glycine, alanine, leucine, isoleucine, and tranexamic acid, an oil that is liquid at 25°C in an amount of 15% by mass or more based on the total mass of the gelled oil-in-water emulsion composition; a nonionic emulsifier in an amount of 5% by mass or more based on the total mass of the gelled oil-in-water emulsion composition; an anionic emulsifier; Water, A gel-like oil-in-water emulsion composition comprising:

2. 2. The gel-like oil-in-water emulsion composition according to claim 1, wherein the content of the oil relative to the total mass of the gel-like oil-in-water emulsion composition is 20 mass % or more.

3. 3. The gel-like oil-in-water emulsion composition according to claim 1, wherein a content of the oil relative to a total mass of the gel-like oil-in-water emulsion composition is 29 mass % or less.

4. The gel-like oil-in-water emulsion composition according to any one of claims 1 to 3, which is a cosmetic product.

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