Transparent gel-like oil-in-water emulsion

Abstract

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

Description

[Technical field]

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

[0002] In the fields of cosmetics, food, medicines, etc., gelling agents are widely used to impart viscosity or elasticity to products. For example, in the field of cosmetics, gelling agents are used to impart viscosity or elasticity to cosmetics for the purpose of improving the feeling of use when the cosmetics are applied to the skin, preventing dripping, etc.

[0003] From the viewpoint of cosmetic transparency, polymer thickeners such as carboxyvinyl polymers are used as gelling agents. However, cosmetics containing polymer thickeners tend to be very sticky, which may reduce the feel of the cosmetics when used.

[0004] In recent years, it has been reported that a gel-like oil-in-water emulsion composition having excellent transparency can be prepared by forming an oil phase component into fine emulsion particles using a high-pressure emulsifier. According to the above method, since there is no need to use a polymer thickener, it is possible to obtain a cosmetic preparation that has an excellent feeling of use with reduced stickiness.

[0005] Patent Document 1 proposes a cosmetic preparation containing at least one selected from the group consisting of nicotinamide, monosaccharides, and oligosaccharides, and a water-soluble film-forming polymer, as a gel-like oil-in-water emulsion composition. Furthermore, Patent Document 2 proposes an external skin preparation and a cosmetic composition containing nicotinamide, liquid oil, a nonionic emulsifier, an anionic emulsifier, and water. Furthermore, Patent Document 3 proposes an oil-in-water emulsion composition containing nicotinamide, liquid oil, a nonionic emulsifier, and water. Furthermore, Patent Document 4 proposes a gel-like oil-in-water emulsion composition containing liquid oil, a nonionic emulsifier, an anionic emulsifier, and water. Furthermore, Patent Document 5 proposes a cosmetic preparation containing an oil-in-water emulsion composition that contains liquid oil, an anionic emulsifier, and water. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2006-22051 A [Patent Document 2] JP 2019-131492 A [Patent Document 3] JP 2018-168105 A [Patent Document 4] JP 2017-105766 A [Patent Document 5] JP 2008-137956 A Summary of the Invention [Problem to be solved by the invention]

[0007] Appearance is also important for cosmetics, and excellent transparency is often required. However, if a polymer thickener is not used, coalescence of emulsion particles contained in a gel-like oil-in-water emulsion composition occurs over time, and the transparency of the gel-like oil-in-water emulsion composition may decrease. Furthermore, the cosmetics proposed in Patent Documents 1 and 2, and the oil-in-water emulsion composition proposed in Patent Document 3, are susceptible to coalescence of emulsion particles over time, and there is room for improvement in terms of stability over time.

[0008] Furthermore, if the hardness of a gel-like oil-in-water emulsion composition is insufficient, it may become difficult to maintain the gel structure, and therefore, the gel-like oil-in-water emulsion composition is required to have high hardness. Furthermore, the oil-in-water emulsion compositions proposed in Patent Documents 4 and 5 do not have sufficient hardness, and there is room for improvement.

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

[0010] <1> A transparent gel-like oil-in-water emulsion composition comprising: nicotinamide; an oil that is liquid at 25°C in an amount of 15% by mass or more based on the total mass of the transparent 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 transparent gel-like oil-in-water emulsion composition; an anionic emulsifier; and water. <2> The absorbance at a wavelength of 625 nm measured with an optical path length of 1 cm is less than 0.08. <1> 2. A transparent gel-like oil-in-water emulsion composition according to claim 1. <3> The content of the nicotinamide relative to the total mass of the transparent gel-like oil-in-water emulsion composition is 2% by mass to 5% by mass. <1> or <2> 2. A transparent gel-like oil-in-water emulsion composition according to claim 1. <4> The content of the oil that is liquid at 25°C relative to the total mass of the transparent gel-like oil-in-water emulsion composition is 20 mass% or more. <1> ~ <3> 1. A transparent gel-like oil-in-water emulsion composition according to any one of claims 1 to 9. <5> The above composition further contains at least one of cholesterol and phytosterol. <1> ~ <4> 1. A transparent gel-like oil-in-water emulsion composition according to any one of claims 1 to 9. <6> The composition further comprises a phytosterol, the phytosterol being a phytosterol polyglyceryl ether. <1> ~ <5> 1. A transparent gel-like oil-in-water emulsion composition according to any one of claims 1 to 9. <7> The composition further comprises a water-soluble moisturizing agent, the water-soluble moisturizing agent being a sugar. <1> ~ <6> 1. A transparent gel-like oil-in-water emulsion composition according to any one of claims 1 to 9. <8> The sugar is trehalose. <7> 2. A transparent gel-like oil-in-water emulsion composition according to claim 1. <9> The cosmetic product <1> ~ <8> 1. A transparent gel-like oil-in-water emulsion composition according to any one of claims 1 to 9. Effect of the Invention

[0011] According to the present disclosure, it is possible to provide a transparent gel-like oil-in-water emulsion composition that is excellent in hardness and stability over time. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing one embodiment of a cosmetic product containing a transparent gel-like oil-in-water emulsion composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 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.

[0014] 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.

[0015] 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.

[0016] In the present disclosure, the term "transparent" for a transparent gel-like oil-in-water emulsion composition means that the absorbance at a wavelength of 625 nm is 0.1 or less, as measured using a spectrophotometer and a cell with an optical path length of 1 cm. The absorbance 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, and stored with the cap on at room temperature (for example, 25° C.) for 24 hours. Next, the measurement object is stored at room temperature for 24 hours and then subjected to a degassing treatment. The degassing treatment is not particularly limited, and examples thereof include centrifugal degassing treatment, vacuum degassing treatment, and vacuum centrifugal degassing treatment. As an example, the mixture is placed in a polystyrene disposable cell with an optical path length of 1 cm, and the whole cell is centrifuged at 4000 rpm (revolutions per minute) for 2 minutes in a small refrigerated centrifuge to degas the mixture. After the degassing treatment, the absorbance of the measurement object with respect to light having a wavelength of 625 nm is measured using a spectrophotometer. The small refrigerated centrifuge is not particularly limited, but for example, the CF5RX manufactured by Hitachi Koki Co., Ltd. can be suitably used. The spectrophotometer is not particularly limited, but for example, U-3310 manufactured by Hitachi, Ltd. can be suitably used.

[0017] In the present disclosure, the "gel-like oil-in-water emulsion composition" of the transparent gel-like oil-in-water emulsion composition refers to a composition in which an oil phase, which is a dispersed phase (emulsion particles), 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] (Transparent gel-like oil-in-water emulsion composition) The transparent gel-like oil-in-water emulsion composition of the present disclosure comprises nicotinamide, an oil that is liquid at 25°C in an amount of 15% by mass or more, based on the total mass of the transparent 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 transparent gel-like oil-in-water emulsion composition, an anionic emulsifier, and water.

[0022] According to the transparent gel-like oil-in-water emulsion composition of the present disclosure, it is possible to provide a transparent gel-like oil-in-water emulsion composition that is excellent in hardness and stability over time.

[0023] The reason why the above effect is achieved is presumed to be as follows, but is not limited to this. The transparent 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 transparent gel-like oil-in-water emulsion composition, which increases the total volume of the emulsion particles (also called oil particles) and increases the interaction between the emulsion particles. It is presumed that the increased interaction between the emulsion particles improves the hardness of the transparent gel-like oil-in-water emulsion composition and enables the gel structure to be maintained for a long period of time. In addition, the transparent gel-like oil-in-water emulsion composition of the present disclosure contains 5% by mass or more of a nonionic emulsifier based on the total mass of the transparent gel-like oil-in-water emulsion composition, which increases the total surface area of ​​the emulsion particles and increases the interaction between the emulsion particles. It is presumed that the increased interaction between the emulsion particles improves the hardness of the transparent gel-like oil-in-water emulsion composition and enables the gel structure to be maintained for a long period of time. The transparent gel-like oil-in-water emulsion composition of the present disclosure also contains nicotinamide. It is presumed that the inclusion of nicotinamide in the transparent gel-like oil-in-water emulsion composition inhibits the coalescence of emulsion particles over time, thereby maintaining excellent transparency for a long period of time.

[0024] From the viewpoint of the stability of the gel structure, the hardness of the transparent gel-like oil-in-water emulsion composition of the present disclosure is preferably 10 g or more, more preferably 40 g or more, even more preferably 50 g or more, particularly preferably 55 g or more, and most preferably 65 g or more. The upper limit of the hardness is not particularly limited, but can be, for example, 150 g or less. In the present disclosure, the 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, and stored with the cap on at room temperature (for example, 25° C.) for 24 hours. Next, the hardness of the measurement object stored at room temperature for 24 hours is measured in the above-mentioned glass container using a viscoelasticity measuring device (so-called rheometer). Specifically, the tip of an adapter with a diameter of 20 mm is inserted 20 mm into a test object stored at room temperature for 24 hours at an ambient temperature of 25°C, with a load of 200 g, and at a speed of 60 mm / min. 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.

[0025] From the viewpoint of transparency, the transparent gel-like oil-in-water emulsion composition of the present disclosure preferably has an absorbance at a wavelength of 625 nm measured over a path length of 1 cm of less than 0.08, more preferably less than 0.07, even more preferably less than 0.05, and particularly preferably less than 0.04. The method for measuring absorbance is as described above.

[0026] From the viewpoint of transparency, the average particle size of the emulsified particles contained in the transparent 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 by diluting the transparent gel-like oil-in-water emulsion composition 100 times by mass with pure water, and then measuring the average particle size at room temperature (eg, 25° C.). The "pure water" used herein is pure water obtained using an ultrapure water production apparatus manufactured by Merck Ltd.

[0027] (nicotinamide) Nicotinamide is a water-soluble vitamin, and a transparent gel-like oil-in-water emulsion composition containing nicotinamide has wrinkle improving effects, rough skin improving effects, whitening effects, and the like. Furthermore, as described above, by containing nicotinamide in the transparent gel-like oil-in-water emulsion composition of the present disclosure, the temporal stability of the transparent gel-like oil-in-water emulsion composition is improved.

[0028] From the viewpoint of hardness and stability over time, the content of nicotinamide relative to the total mass of the transparent gel-like 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 5% by mass. Furthermore, by setting the content of nicotinamide within the above numerical range, stickiness of the transparent gel-like oil-in-water emulsion composition can be suppressed.

[0029] (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 transparent gel-like oil-in-water emulsion composition of the present disclosure. From the viewpoint of suppressing stickiness, it is preferable to use a hydrocarbon oil and a silicone oil in combination.

[0030] 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.

[0031] The silicone oil is not particularly limited as long as it contains a siloxane structure and is liquid at 25°C. Silicone oils include dimethicone, trisiloxane, cyclomethicone, cyclopentasiloxane, methyl trimethicone, caprylyl methicone, phenyl trimethicone, diphenyl dimethicone, diphenylsiloxyphenyl trimethicone, and the like. 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.

[0032] 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.).

[0033] From the viewpoint of hardness and stability over time, the content of oil that is liquid at 25° C. relative to the total mass of the transparent gel-like 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 transparent gel-like oil-in-water emulsion composition is preferably 30 mass % or less, and more preferably 25 mass % or less.

[0034] When a hydrocarbon oil and a silicone oil are used in combination, from the viewpoints of hardness and stability 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.

[0035] (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 over time, among the above, the nonionic emulsifier is preferably a fatty acid ester. 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.

[0036] From the viewpoints of hardness, stability over time, and suppression of stickiness, the content of the nonionic emulsifier relative to the total mass of the transparent gel-like oil-in-water emulsion composition is preferably 5.3% by mass to 8% by mass, and more preferably 5.5% by mass to 7% by mass.

[0037] (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 hardness and stability over time.

[0038] Examples of glutamic acid salts include acyl glutamic acid salts, sodium surfactin, and the like, and from the viewpoints of hardness and stability over time, acyl glutamic acid salts are preferred.

[0039] 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, sodium dilauroyl glutamate lysine, etc. 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, disodium N-stearoyl-L-glutamate, etc.

[0040] From the viewpoint of stability over time, the content of the anionic emulsifier relative to the total mass of the transparent gel-like oil-in-water emulsion composition is preferably 0.1 to 5% by mass, and more preferably 0.3 to 3% by mass.

[0041] (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.

[0042] The content of water relative to the total mass of the transparent gel-like oil-in-water emulsion composition is not particularly limited, and can be 30% by mass to 70% by mass.

[0043] (Cholesterol and Phytosterols) From the viewpoint of stability over time, it is preferable that the transparent gel-like oil-in-water emulsion composition of the present disclosure further contains at least one of cholesterol and phytosterol.

[0044] Examples of cholesterol include cholesterol, dihydrocholesterol, dehydrocholesterol, cholesteryl oleate, cholesteryl isostearate, cholesteryl hydroxystearate, polyoxyethylene cholesteryl ether, and the like.

[0045] The phytosterol is preferably a phytosterol polyglyceryl ether, and more preferably a phytosterol polyglyceryl ether having a polyoxyethylene group (hereinafter also referred to as polyoxyethylene phytosterol). Examples of phytosterols include sitosterol, stigmasterol, fucosterol, spinasterol, and brassicasterol.

[0046] From the viewpoint of stability over time, the average number of moles of oxyethylene groups added to the polyoxyethylene phytosterol is preferably not less than 5. Note that the average number of moles of oxyethylene groups added to the polyoxyethylene phytosterol can be found in the catalogue.

[0047] 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 transparent gel-like 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 transparent gel-like oil-in-water emulsion composition" means the cholesterol content when the transparent gel-like oil-in-water emulsion composition contains only cholesterol, means the phytosterol content when the transparent gel-like oil-in-water emulsion composition contains only phytosterol, and means the sum of these contents when the transparent gel-like oil-in-water emulsion composition contains both cholesterol and phytosterol.

[0048] (Water-soluble moisturizer) The transparent gel-like oil-in-water emulsion composition of the present disclosure may contain a water-soluble moisturizing agent. From the viewpoint of suppressing stickiness, the water-soluble moisturizing agent is preferably at least one of a sugar and an amino acid, and more preferably a sugar. In the present disclosure, the sugar includes derivatives. Examples of the sugar derivatives include sugars modified with an oxyethylene group.

[0049] Examples of sugars include glucose, sucrose, sorbitol, trehalose, maltose, mannitol, maltotriose, etc. Examples of amino acids include arginine, alanine, glycine, methionine, aspartic acid, lysine, serine, sarcosine, trimethylglycine, etc. Among the above, from the viewpoints of transparency and stability over time, at least one of sucrose, sorbitol, and trehalose is preferred, and trehalose is more preferred.

[0050] From the viewpoint of suppressing stickiness, the content of the water-soluble moisturizing agent relative to the total mass of the transparent 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.

[0051] From the viewpoint of stability over time and suppression of stickiness, the sum of the contents of nicotinamide and water-soluble moisturizer relative to the total mass of the transparent gel-like oil-in-water emulsion composition is preferably 10 mass% or more, more preferably 11 mass% or more, and even more preferably 12 mass% or more. Furthermore, the sum of the contents of nicotinamide and water-soluble moisturizer relative to the total mass of the transparent gel-like oil-in-water emulsion composition is preferably 25 mass% or less, more preferably 20 mass% or less, and even more preferably 17 mass% or less.

[0052] (others) The transparent 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.). The gel-like oil-in-water emulsion composition of the present disclosure may also contain liposomes encapsulating cosmetic ingredients such as caffeine, pyridoxine hydrochloride, nicotinamide, etc. The liposomes may have a single lamellar structure with a single lipid bilayer, or may have a multilamellar structure with multiple lipid bilayers, but from the viewpoint of the amount of encapsulated ingredients, those having a single lamellar structure are preferred.

[0053] (Polymer thickener) From the viewpoint of suppressing stickiness, when the transparent gel-like 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 transparent gel-like 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 transparent gel-like oil-in-water emulsion composition of the present disclosure does not contain a polymer thickener.

[0054] (Application) The transparent 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] (Method of producing transparent gel-like oil-in-water emulsion composition) A method for producing the transparent gel-like oil-in-water emulsion composition of the present disclosure will be described below, but is not limited thereto.

[0056] The transparent 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 nicotinamide and water, and then subjecting the mixture to an emulsification treatment.

[0057] 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.

[0058] The aqueous phase composition can be obtained by adding nicotinamide to water and dissolving it by heating. Ethanol, water-soluble moisturizers, preservatives, fragrances, etc. may be added to the water.

[0059] The emulsification treatment is preferably carried out under high pressure conditions, since this allows obtaining fine emulsion particles and improves the transparency of the transparent gel-like 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.

[0060] 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.

[0061] Examples of ultrasonic homogenizers include ultrasonic homogenizers US-600, US-1200T, RUS-1200T, and MUS-1200T manufactured by Nippon Seiki Seisakusho Co., Ltd., and ultrasonic processors UIP2000, UIP-4000, UIP-8000, and UIP-16000 manufactured by Hielscher AG. These high-output ultrasonic irradiation devices are preferably used at a frequency of 25 kHz or less, more preferably 15 kHz to 20 kHz.

[0062] 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 such a filter include the Nanomizer (manufactured by Dix Co., Ltd.), the Nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.), and the 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.).

[0063] The produced transparent 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.

[0064] (Cosmetic products) The cosmetic product 10 of the present disclosure comprises a pump 12 with a discharge port 11, a head portion 14 with a suction tube 13 connected to the pump 12, and a container 16 with a main body portion 15, and the above-mentioned gel-like oil-in-water emulsion composition 17 contained in the main body portion 15 (see FIG. 1). The suction tube 13 is connected to the pump 12 (dotted line portion in FIG. 1). In the present disclosure, the length of the suction tube refers to the length from the tip of the suction tube on the main body side to the connection part with the pump (indicated by the symbol α in FIG. 1). In addition, reference numeral 18 in FIG. 1 denotes a connecting portion for attaching the head portion 14 to the main body portion 15.

[0065] At the start of use, it is preferable that the length of the suction tube is short, since this reduces the number of times the pump needs to be pressed before discharging. Specifically, the ratio of the length of the liquid suction tube to the length of the head portion is preferably 10% to 100%, more preferably 15% to 80%, and even more preferably 30% to 60%. In this disclosure, the length of the head portion refers to the length from the tip of the suction tube on the main body side to the upper end of the pump (indicated by the symbol β in FIG. 1). Note that the upper end of the pump refers to the part of the pump where the length from the tip of the suction tube on the main body side is at its maximum.

[0066] The container is preferably an airless pump container from the viewpoints of the hardness and stability over time of the contained transparent gel-like oil-in-water emulsion composition, and the dischargeability of the container. An airless pump container has a mechanism in which, when the pump is pressed, the air inside the main body is released and the cosmetic is sucked up by a suction tube. By providing the container with this mechanism, the airtightness of the main body is improved and the intrusion of germs from the outside air can be suppressed, thereby improving the stability of the cosmetic over time. From the viewpoint of stability over time, the airless pump container preferably has a valve at the pump outlet (hereinafter, an airless pump container having a valve at the pump outlet is also referred to as a shut-off airless pump container). From the viewpoint of reducing the amount of the transparent gel-like oil-in-water emulsion composition remaining after use, the container preferably has a delamination multilayer structure. A container having a delamination multilayer structure refers to a container having an inner layer and an outer layer that are not bonded or welded to each other. The container may also include a cap that is attached to the head portion. An example of an airless container having a multi-layer delamination structure is SP-200-HVD manufactured by Yoshino Kogyosho Co., Ltd., and an example of a shut-off airless container having a multi-layer delamination structure is NP-200-HVD manufactured by Yoshino Kogyosho Co., Ltd.

[0067] The transparent gel-like oil-in-water emulsion composition is preferably filled into a container by aseptic filling.

[0068] 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

[0069] 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 value of each component in Table 1 indicates the content (mass%) of each component relative to the total mass of the gel-like oil-in-water emulsion composition.

[0070] <Examples 1 to 14> (Preparation of Oil Phase Composition A) The nonionic emulsifier, anionic emulsifier, lecithin, and astaxanthin shown in Table 1 below were added to a liquid oil at 25°C, and dissolved by heating at 70°C for 30 minutes to obtain an oil phase composition A. In Examples 4 to 6, 11 to 12, and 14, phytosterol or cholesterol was also added.

[0071] (Preparation of Aqueous Phase Composition A) The 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 A.

[0072] (Production of gel-like oil-in-water emulsion composition) While stirring the aqueous phase composition, the oil phase composition A was added to the aqueous phase composition A, and a preliminary emulsion was obtained by ultrasonic treatment for 1 minute per 100 g using an ultrasonic homogenizer (Nippon Seiki Seisakusho Co., Ltd., US-600). 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.

[0073] The details of each component in Table 1 are as follows: Nicotinamide: Niacinamide PC, manufactured by DSM Nonionic emulsifier A: Sucrose stearate Nonionic emulsifier B: Glyceryl stearate Nonionic emulsifier C: Polyglyceryl-5 oleate Nonionic emulsifier D: Polyglyceryl-10 laurate Nonionic emulsifier E: Polyglyceryl-10 oleate Nonionic emulsifier F: Polyglyceryl-10 palmitate Anionic emulsifier: Sodium N-stearoyl-L-glutamate Phytosterol A: Polyoxyethylene phytosterol, Nikkol (registered trademark) BPS-5, manufactured by Nikko Chemicals Co., Ltd. Cholesterol A: EMALEX (registered trademark) CS-5, manufactured by Nippon Emulsion Industry Co., Ltd. Lecithin A: H. Holstein, LIPOID P-75 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℃ Water-soluble moisturizer: Trehalose · Preservative: Methylparaben Ethanol: Made by Japan Alcohol Industry Co., Ltd., Traceable 99 (Grade 1)

[0074] <Example 15> A gel-like oil-in-water emulsion composition was obtained in the same manner as in Example 11, except that 2% by mass of water was replaced with the caffeine-containing liposome composition prepared as follows.

[0075] (Preparation of caffeine-containing liposome composition) (Preparation of Oil Phase Composition) The following ingredients were mixed and dissolved by heating at 60° C. for 10 minutes to obtain an oil phase composition B. -Oil phase composition B- Lecithin B 55.0g Phytosterol B 11.5g Cholesterol B 15.0g Absolute ethanol 1005.0g Ascorbic acid 5.0g

[0076] The following components were mixed and dissolved by heating at 60° C. for 10 minutes to obtain an aqueous phase composition B. -Aqueous phase composition B- 50.0g anhydrous caffeine Nicotinamide 5.0g 6.5g anhydrous sodium monohydrogen phosphate Sodium dihydrogen phosphate 0.3g ·Purified water 3847.0g

[0077] The following components were mixed and dissolved by heating at 60° C. for 10 minutes to obtain an aqueous phase composition C. -Aqueous phase composition C- Methyl parahydroxybenzoate 20.0g ·Purified water 4980.0g

[0078] The aqueous phase composition B was stirred (4000 rpm) with a homomixer (Automixer 40 model, manufactured by Primix Corporation) while being kept at 60° C. Next, the oil phase composition B was added to the aqueous phase composition B, and stirring was continued at 4000 rpm for 60 minutes. After stirring, the aqueous phase composition C was further added, the mixture was stirred uniformly for 5 minutes, and then cooled to 35°C or lower. After cooling, the mixture was filtered through a 230 mesh filter cloth to obtain a caffeine-containing liposome composition containing liposomes encapsulating caffeine. A TEM (Transmission Electron Microscope) image of the obtained caffeine-containing liposome composition was obtained at a magnification of 50,000 times using a transmission electron microscope, and liposomes having a single lamellar structure were observed.

[0079] The details of each of the above components are as follows. Lecithin B: Hydrogenated soybean phospholipid, NOF Corporation, COATSOME NC-21 Phytosterol B: Polyoxyethylene phytosterol, Nikkol (registered trademark) BPS-20, manufactured by Nikko Chemicals Co., Ltd. Cholesterol B: Cholesterol JSQI, manufactured by Nippon Fine Chemicals Co., Ltd. Absolute ethanol: Kanto Chemical Co., Ltd., Traceable 99 (Grade 1) Ascorbic acid: Ascorbyl tetra 2-hexyldecanoate, Nikkol (registered trademark) VC-IP, manufactured by Nikko Chemicals Co., Ltd. Anhydrous caffeine: Manufactured by Mitsubishi Chemical Foods Corporation Nicotinamide: Niacinamide PC, manufactured by DSM - Sodium monohydrogen phosphate anhydrous: Taihei Chemical Industry Co., Ltd. (quasi-drug raw material standard) Sodium dihydrogen phosphate: Manufactured by Taihei Chemical Industry Co., Ltd. Methyl paraoxybenzoate: Ueno Pharmaceutical Co., Ltd., Mekkinsu M

[0080] <Comparative Example 1> A gel-like oil-in-water emulsion composition was obtained in the same manner as in Example 1, except that nicotinamide was not used.

[0081] <Comparative Example 2> A gel-like oil-in-water emulsion composition was obtained in the same manner as in Example 1, except that nicotinamide was not used and the content of oil that was liquid at 25° C. was less than 15 mass %.

[0082] <Comparative Example 3> A gel-like oil-in-water emulsion composition was obtained in the same manner as in Example 1, except that the content of the nonionic emulsifier was less than 5 mass %.

[0083] <<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 stored with the cap on for 24 hours at 25° C. Note that 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 composition 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 measured as hardness. The measured hardness was evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1. The hardness of the gel-like oil-in-water emulsion compositions obtained in Comparative Examples 2 and 3 was less than 10 g, and the following evaluations were not carried out. (Evaluation Criteria) A: The hardness was 65 g or more, and the composition was recognized as a gel-like oil-in-water emulsion composition having extremely excellent stability of the gel structure. B: The hardness was 40 g or more and less than 65 g, and the composition was recognized as a gel-like oil-in-water emulsion composition having excellent stability of the gel structure. C: The hardness was 10 g or more and less than 40 g, and the composition was recognized as a gel-like oil-in-water emulsion composition having a gel structure stability that is practically acceptable. D: The hardness was less than 10 g, and the gel structure was an oil-in-water emulsion composition in a gel state, and the stability of the gel structure was insufficient.

[0084] <<Transparency rating-1>> 100 g of the gel-like oil-in-water emulsion composition obtained in the above Examples and Comparative Examples was placed in a glass container with a diameter of 47 mm and a height of 90 mm, and stored at 25° C. for 24 hours with the cap on. The gel-like oil-in-water emulsion composition after 24 hours of storage at 25° C. was placed in a polystyrene disposable cell with an optical path length of 1 cm, and the cell was centrifuged at 4000 rpm for 2 minutes using a small refrigerated centrifuge (manufactured by Hitachi Koki Co., Ltd., CF5RX, swing rotor: T4SS31) to perform defoaming treatment. The gel-like oil-in-water emulsion composition used was a gel-like oil-in-water emulsion composition immediately after production (within 24 hours after production). After the defoaming treatment, the absorbance of the gel-like oil-in-water emulsion composition at a wavelength of 625 nm was measured using a spectrophotometer (U-3310, manufactured by Hitachi, Ltd.). The transparency of the gel-like oil-in-water emulsion compositions obtained in the above Examples and Comparative Examples was evaluated based on the following evaluation criteria, and the evaluation results are summarized in Table 1. (Evaluation Criteria) A: The absorbance was less than 0.04, and extremely excellent transparency was confirmed. B: The absorbance was 0.04 or more and less than 0.08, and excellent transparency was confirmed. C: The absorbance was 0.08 or more and 0.1 or less, and transparency was confirmed. D: The absorbance was more than 0.1 and the transparency was insufficient.

[0085] <<Transparency Rating-2>> The gel-like oil-in-water emulsion compositions obtained in the above Examples and Comparative Examples were stored for 14 days in an environment at 50° C. After storage, the absorbance of the gel-like oil-in-water emulsion compositions was measured in the same manner as in the above transparency evaluation. The transparency of the gel-like oil-in-water emulsion compositions obtained in the above Examples and Comparative Examples was evaluated based on the following evaluation criteria, and the evaluation results are summarized in Table 1. (Evaluation Criteria) A: The absorbance was less than 0.04, and extremely excellent transparency was confirmed. B: The absorbance was 0.04 or more and less than 0.08, and excellent transparency was confirmed. C: The absorbance was 0.08 or more and 0.1 or less, and transparency was confirmed. D: The absorbance was more than 0.1 and the transparency was insufficient.

[0086] <<Evaluation of stability over time>> The difference between the absorbance of the gel-like oil-in-water emulsion composition immediately after production obtained in the above Transparency Evaluation-1 and the absorbance of the gel-like oil-in-water emulsion composition after storage obtained in the above Transparency Evaluation-2 (absorbance of the gel-like oil-in-water emulsion composition immediately after production - absorbance of the gel-like oil-in-water emulsion composition after storage) was determined, and the stability over time was evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1. (Evaluation Criteria) A: The absorbance difference was 0.01 or less. B: The absorbance difference was more than 0.01 and less than 0.03. C: The absorbance difference was more than 0.03.

[0087] [Table 1]

[0088] The results in Table 1 show that the gel-like oil-in-water emulsion compositions obtained in the Examples have superior hardness and gel structure stability compared to Comparative Example 2, in which the content of liquid oil at 25°C was less than 15 mass%, and Comparative Example 3, in which the content of nonionic emulsifier was less than 5 mass%. Furthermore, the results in Table 1 show that the gel-like oil-in-water emulsion compositions obtained in the Examples have superior stability over time and can maintain excellent transparency for a long period of time, compared to Comparative Example 1, which does not use nicotinamide.

[0089] <<Measurement of the average particle size of emulsion particles>> The gel-like oil-in-water emulsion composition obtained in Example 15 was diluted 100 times by mass with pure water, and the average particle size of the emulsified particles contained in the gel-like oil-in-water emulsion composition was measured using a dynamic light scattering particle size analyzer (Otsuka Electronics Co., Ltd., Concentrated System Particle Size Analyzer FPAR-1000) to find that it was 59 nm.

[0090] <<Evaluation of ejection properties>> A shut-off airless container A (manufactured by Yoshino Kogyosho Co., Ltd., NP-200-HVD) having a delamination multi-layer structure was prepared. The length of the head portion of the shut-off airless container A was 30 mm, the length of the suction tube was 43.5 mm, and the internal volume (overflow volume) of the main body was 52.0 mL. In addition, shut-off airless container B having a delamination multi-layer structure with the suction tube length changed to 32.0 mm and shut-off airless container C having a delamination multi-layer structure with the suction tube length changed to 18.5 mm were prepared.

[0091] The gel-like oil-in-water emulsion composition obtained in Example 15 was filled in an amount of 47.25 g into the shut-off airless containers A to C (referred to as containers A to C, respectively, in the table). The number of pump strokes required until the gel-like oil-in-water emulsion composition was expelled from the shut-off airless container was determined and is shown in Table 2.

[0092] [Table 2]

[0093] From all of the shut-off airless containers A to C, the gel-like oil-in-water emulsion composition could be discharged within 10 pump presses, confirming good discharge performance. [Explanation of symbols]

[0094] 10: cosmetic product, 11: discharge port, 12: pump, 13: suction tube, 14: head portion, 15: main body portion, 16: storage container, 17: gel-like oil-in-water emulsion composition, 18: connecting portion, α: length of suction tube, β: length of head portion

Claims

1. Nicotinamide, an oil that is liquid at 25°C in an amount of 15% by mass or more based on the total mass of the transparent 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 transparent gel-like oil-in-water emulsion composition; an anionic emulsifier; Water, A transparent gel-like oil-in-water emulsion composition comprising:

2. 2. The transparent gel-like oil-in-water emulsion composition according to claim 1, having an absorbance at a wavelength of 625 nm measured with an optical path length of 1 cm of less than 0.

08.

3. 3. The transparent gel-like oil-in-water emulsion composition according to claim 1, wherein the content of said nicotinamide is 2% by mass to 5% by mass based on the total mass of the transparent gel-like oil-in-water emulsion composition.

4. 4. The transparent gel-like oil-in-water emulsion composition according to claim 1, wherein a content of the oil that is liquid at 25° C. relative to a total mass of the transparent gel-like oil-in-water emulsion composition is 20 mass % or more.

5. The transparent gel-like oil-in-water emulsion composition according to any one of claims 1 to 4, further comprising at least one of cholesterol and phytosterol.

6. Contains phytosterols, 6. The transparent gel-like oil-in-water emulsion composition according to any one of claims 1 to 5, wherein the phytosterol is a phytosterol polyglyceryl ether.

7. Contains water-soluble moisturizers, 7. The transparent gel-like oil-in-water emulsion composition according to claim 1, wherein the water-soluble moisturizing agent is a sugar.

8. 8. The transparent gel-like oil-in-water emulsion composition according to claim 7, wherein the sugar is trehalose.

9. The transparent gel-like oil-in-water emulsion composition according to any one of claims 1 to 8, which is a cosmetic product.

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