Emulsion-type cosmetic

Abstract

The present invention provides an emulsion-type cosmetic that is stable at high and low temperatures, has superior antiseptic properties and an excellent appearance, contains (A) an acyl amino acid ester, (B) lecithin, (C) a polyhydric alcohol with 5 or less carbon atoms, and (D) a buffer solution containing a carboxylic acid with 3 or more carbon atoms, includes 0.1-20 wt% of (A), 0.05-10 wt% of (B), and 0.5-20 wt% of (C) relative to the total weight of the emulsion-type cosmetic, and has a carboxylic acid ion content of 0.5-10 mmol and a pH of 3-8.

Description

Emulsion-type cosmetics

[0001] The present invention relates to an emulsion-type cosmetic that is stable when stored at low to high temperatures and has excellent antiseptic properties, and a method for producing the same.

[0002] Emulsion-type cosmetics that can impart moisturizing and barrier functions to the skin are widely used, and recent advances in nanoemulsion technology have led to the development of various emulsion-type cosmetics containing fine emulsion particles that offer excellent penetration and a pleasant feel when used. For example, emulsion-type cosmetics that use amino acid-based oils to provide a sustained moisturizing effect similar to that inherent to skin (Patent Documents 1 and 2) are known. However, because emulsion-type cosmetics are prepared by emulsifying water and oil, their structure poses problems with stability over time. To address this issue, methods have been reported that improve stability over time by blending and emulsifying 1,2-hexanediol in a specific ratio with oily ingredients, lecithin, and polyglyceryl laurate. However, it is known that the stability over time and the pleasant feel when 1,2-hexanediol is used in amounts exceeding 2.5% by weight (Patent Document 3).

[0003] On the other hand, preservative-free cosmetics have become popular recently, and there is a demand for emulsion-type cosmetics that can be imparted with antiseptic properties by means other than the addition of preservatives.

[0004] JP 2006-089420 A WO2023 / 085272 JP 2013-56858 A

[0005] Therefore, an object of the present invention is to provide an emulsion-type cosmetic that is stable at both high and low temperatures, has excellent antiseptic properties, and provides a good feeling when used.

[0006] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that in emulsion-type cosmetics containing an N-acyl-L-glutamic acid diester or the like, increasing the amount of a polyol having antiseptic properties to a concentration at which the antiseptic properties can be exerted actually results in a decrease in stability. However, they have also found that using pentylene glycol in combination with a citrate buffer makes it possible to achieve both antiseptic properties and stability, and further research has led to the completion of the present invention.

[0007] That is, the present invention relates to the following: [1] An emulsion-type cosmetic comprising (A) an acyl amino acid ester, (B) lecithin, (C) a polyhydric alcohol having 5 or less carbon atoms, and (D) a buffer solution containing a carboxylic acid having 3 or more carbon atoms, wherein the emulsion-type cosmetic contains 0.1 to 20 wt% of (A), 0.05 to 10 wt% of (B), and 0.5 to 20 wt% of (C) relative to the total weight of the emulsion-type cosmetic, and the emulsion-type cosmetic has a carboxylate ion content of 0.5 to 10 mmol and a pH of 3 to 8. [2-1] The emulsion-type cosmetic according to [1], wherein the (A) acyl amino acid ester is an acyl acidic amino acid ester. [2-2] The emulsion-type cosmetic according to [1], wherein the (A) acyl amino acid ester is an acyl glutamic acid ester. [2-3] The emulsion-type cosmetic according to [1], wherein the (A) acyl amino acid ester is an acyl glutamic acid diester. [2-4] The emulsion cosmetic according to [1], wherein (A) the acyl amino acid ester is N-lauroyl-L-glutamic acid di(phytosteryl / octyldodecyl). [3] The emulsion cosmetic according to any one of [1] to [2-4], wherein (C) the polyhydric alcohol having 5 or less carbon atoms is pentylene glycol. [4] The emulsion cosmetic according to any one of [1] to [3], wherein (D) the carboxylic acid having 3 or more carbon atoms is citric acid. [5] The emulsion cosmetic according to any one of [1] to [4], wherein (B) the lecithin is hydrogenated lecithin. [6] The emulsion cosmetic according to any one of [1] to [5], further comprising (E) a polyglycerin fatty acid ester. [7] The emulsion cosmetic according to any one of [1] to [6], wherein (A) further comprises N-lauroyl-L-glutamic acid di(phytosteryl / octyldodecyl / behenyl). [8] The emulsion cosmetic according to any one of [1] to [7], wherein the average particle size of the emulsion particles of the emulsion cosmetic is 90 to 200 nm.[9] A method for producing an emulsion-type cosmetic, comprising the steps of: homogenizing an oil phase component containing (A) an acylamino acid ester and (B) lecithin; adding and mixing an aqueous phase component containing (C) a polyhydric alcohol having 5 or less carbon atoms and (D) a buffer solution containing a carboxylic acid having 3 or more carbon atoms to the oil phase component; and emulsifying the mixture obtained in the above step under high pressure, wherein the amounts of (A) added relative to the total weight of the emulsion-type cosmetic are 0.1 to 20 wt %, (B) 0.05 to 10 wt %, and (C) 0.5 to 20 wt %, and the emulsion-type cosmetic has a carboxylate ion content of 0.5 to 10 mmol and a pH of 3 to 8. [10-1] The method according to [9], wherein the (A) acylamino acid ester is an acyl acidic amino acid ester. [10-2] The method according to [9], wherein the (A) acylamino acid ester is an acyl glutamic acid ester. [10-3] The method according to [9], wherein the (A) acylamino acid ester is an acyl glutamic acid diester. [10-4] The production method according to [9], wherein (A) the acyl amino acid ester is N-lauroyl-L-glutamic acid di(phytosteryl / octyldodecyl).

[11] The production method according to any one of [9] to [10-4], wherein (C) the polyhydric alcohol having 5 or less carbon atoms is pentylene glycol.

[12] The production method according to any one of [9] to

[11] , wherein (D) the carboxylic acid having 3 or more carbon atoms is citric acid.

[13] The production method according to any one of [9] to

[12] , wherein (B) the lecithin is hydrogenated lecithin.

[14] The production method according to any one of [9] to

[13] , further comprising a step of adding (E) a polyglycerol fatty acid ester to the aqueous phase component.

[15] The production method according to any one of [9] to

[14] , wherein (A) further comprises N-lauroyl-L-glutamic acid di(phytosteryl / octyldodecyl / behenyl).

[16] A manufacturing method according to any one of [9] to

[15] , wherein the emulsion particles of the emulsion cosmetic have an average particle size of 90 to 200 nm.

[17] A cosmetic comprising the emulsion cosmetic according to any one of [1] to [8].

[18] A manufacturing method for a cosmetic comprising a step of adding the emulsion cosmetic according to any one of [1] to [8].

[19] An emulsion cosmetic obtained by the manufacturing method according to any one of [9] to

[16] .

[20] A cosmetic obtained by the manufacturing method described in

[18] .

[0008] The present invention can provide an emulsion-type cosmetic preparation that contains an acylamino acid ester and is excellent in both stability and preservative properties. The present invention can also provide an emulsion-type cosmetic preparation that does not require the addition of preservatives.

[0009] The present invention relates to an emulsion-type cosmetic comprising a buffer solution containing (A) an acylamino acid ester, (B) lecithin, (C) a polyhydric alcohol having 5 or less carbon atoms, and (D) a carboxylic acid having 3 or more carbon atoms, wherein the emulsion-type cosmetic contains 0.1 to 20 wt % of (A), 0.05 to 10 wt % of (B), and 0.5 to 20 wt % of (C) relative to the total weight of the emulsion-type cosmetic, and the emulsion-type cosmetic has a carboxylate ion content (number of moles) of 0.5 to 10 mmol and a pH of 3 to 8 (also referred to as the emulsion-type cosmetic of the present invention).

[0010] The number of carbon atoms in the acyl group in the acylamino acid ester contained as component (A) in the emulsion-type cosmetic of the present invention is preferably 10 to 30, and more preferably 12 to 18. The acyl group may be saturated or unsaturated. For example, 2-ethylhexanoyl, lauroyl, myristoyl, palmitoyl, stearoyl, behenoyl, oleoyl, isostearoyl, linolenoyl, and the like are preferred, with myristoyl and lauroyl being more preferred, and lauroyl being even more preferred. The acyl group may also be derived from a mixed fatty acid, with cocoyl fatty acid esters, palm oil fatty acid esters, palm kernel oil fatty acid esters, sunflower seed oil fatty acid esters, and macadamia nut oil fatty acid esters being preferred.

[0011] Examples of the alcohol residue constituting the ester in the N-acyl amino acid ester include octyl, lauryl, cetyl, stearyl, isostearyl, behenyl, octyldodecyl, phytosteryl groups such as campesteryl and sitosteryl, cholesteryl, and decyltetradecyl. The amino acid moiety in the N-acyl amino acid ester includes acidic amino acids, neutral amino acids, and basic amino acids, preferably acidic amino acids and neutral amino acids, and more preferably acidic amino acids. More specifically, glutamic acid, aspartic acid, alanine, arginine, glycine, N-methylalanine, histidine, serine, threonine, and sarcosine are preferred, with glutamic acid, aspartic acid, alanine, N-methylalanine, and sarcosine being more preferred, and glutamic acid being even more preferred. Examples of the N-acyl amino acid ester include monoesters and diesters. Examples of monoesters include N-lauroyl sarcosine ester. Examples of diesters include N-lauroyl glutamic acid diester and N-acylaspartic acid diester, with N-lauroyl glutamic acid diester being preferred. The alcohol residues present in one diester molecule may be the same or different, but two or more types are preferred.

[0012] In the present invention, examples of the N-acylamino acid diester include N-lauroyl-L-glutamic acid di(phytosteryl / octyldodecyl), N-lauroyl-L-glutamic acid di(phytosteryl / octyldodecyl / behenyl), N-lauroyl-L-glutamic acid di(cholesteryl / octyldodecyl), and N-lauroyl-L-glutamic acid di(cholesteryl / octyldodecyl / behenyl).

[0013] In the present invention, (A) can be synthesized by a known chemical synthesis method and used. For example, N-lauroyl-L-glutamic acid di(phytosteryl / 2-octyldodecyl) can be a commercially available product (ELDEW (registered trademark) PS-203) provided by Ajinomoto Co., Inc., and N-lauroyl-L-glutamic acid di(phytosteryl / behenyl / 2-octyldodecyl) can be a commercially available product (ELDEW (registered trademark) PS-306) provided by Ajinomoto Co., Inc.

[0014] In the present invention, (A) may be used alone or in combination of two or more. Examples of (A) include N-lauroyl-L-glutamic acid di(phytosteryl / octyldodecyl), N-lauroyl-L-glutamic acid di(phytosteryl / octyldodecyl / behenyl), N-lauroyl-L-glutamic acid di(cholesteryl / octyldodecyl), N-lauroyl-L-glutamic acid di(cholesteryl / octyldodecyl / behenyl), and N-lauroylsarcosine isopropyl.

[0039] Preferred are di(phytosteryl / 2-octyldodecyl) N-lauroyl-L-glutamate, di(phytosteryl / behenyl / 2-octyldodecyl) N-lauroyl-L-glutamate, di(cholesteryl / octyldodecyl) N-lauroyl-L-glutamate, and di(cholesteryl / octyldodecyl / behenyl) N-lauroyl-L-glutamate, and more preferred is di(phytosteryl / 2-octyldodecyl) N-lauroyl-L-glutamate. Furthermore, (A) may be a combination of di(phytosteryl / 2-octyldodecyl) N-lauroyl-L-glutamate and di(phytosteryl / behenyl / 2-octyldodecyl) N-lauroyl-L-glutamate. For example, when component (A) contains di(phytosteryl / 2-octyldodecyl) N-lauroyl-L-glutamate (A-1) and di(phytosteryl / behenyl / 2-octyldodecyl) N-lauroyl-L-glutamate (A-2), the weight ratio of (A-1):(A-2) is not particularly limited as long as the effects of the present invention are not impaired, but is usually 1:0.1-10, preferably 1:0.2-5.

[0015] The content of component (A) in the emulsion cosmetic of the present invention is usually 0.1 to 20% by weight, preferably 0.5 to 10% by weight, and more preferably 1 to 10% by weight, relative to the total weight of the emulsion cosmetic.

[0016] The lecithin contained as component (B) in the emulsion cosmetic of the present invention is a lipid mixture containing phospholipids such as phosphatidylcholine, and examples thereof include soybean lecithin obtained from soybeans and egg yolk lecithin obtained from egg yolk. From the viewpoint of the oxidative stability of the emulsion cosmetic, it is preferable to use hydrogenated lecithin such as hydrogenated soybean phospholipid or hydrogenated egg yolk lecithin. In the emulsion cosmetic of the present invention, one type of lecithin can be used alone, or two or more types can be used in combination.

[0017] In the present invention, the above-mentioned lecithin can be extracted from soybeans, egg yolk, etc. and purified before use, but commercially available products provided by various companies can also be used. The content of component (B) in the emulsion cosmetic of the present invention is usually 0.05% by weight to 10% by weight, preferably 0.1% by weight to 5% by weight, and more preferably 0.5% by weight to 3% by weight, based on the total weight of the emulsion cosmetic.

[0018] The polyhydric alcohol having 5 or less carbon atoms contained as component (C) in the emulsion cosmetic of the present invention is a compound having 5 or less carbon atoms and two or more hydroxy groups (—OH). Specific examples of polyhydric alcohols having 5 or less carbon atoms include glycerin, propylene glycol, 1,3-butylene glycol, pentylene glycol (1,2-pentanediol), ethylene glycol, and diethylene glycol. Of these, pentylene glycol, a dihydric alcohol having two hydroxy groups bonded to it, is preferred.

[0019] Pentylene glycol can be produced by a known method, but commercially available products available from various companies can also be used.

[0020] From the viewpoint of preservative properties, the content of component (C) in the emulsion cosmetic of the present invention is typically 0.5 wt% or more, preferably 1 wt% or more, more preferably 2 wt% or more, even more preferably 2.5 wt% or more, particularly preferably 3 wt% or more, and most preferably 4 wt% or more, relative to the total weight of the emulsion cosmetic. The upper limit of the content is 20 wt% or less, 10 wt% or less, more preferably 8 wt% or less, and even more preferably 7.5 wt% or less. More specifically, the content is typically 0.5 wt% to 20 wt%, preferably 1 wt% to 10 wt%, more preferably 2 wt% to 8 wt%, even more preferably 2.5 wt% to 7.5 wt%, particularly preferably 3 wt% to 7.5 wt%, and most preferably 4 wt% to 7.5 wt%.

[0021] Examples of the carboxylic acid in the buffer solution containing a carboxylic acid having 3 or more carbon atoms contained as component (D) in the emulsion-type cosmetic of the present invention include oxalic acid, citric acid, tartaric acid, malic acid, etc. Among these, a citrate buffer solution is more preferred from the viewpoint of high-temperature stability. The citrate buffer solution may contain citric acid and a citrate salt. Examples of salts contained in the buffer solution include lithium salts, sodium salts, potassium salts, etc., of which sodium salts are preferred, such as trisodium citrate dihydrate.

[0022] The buffer containing a carboxylic acid having 3 or more carbon atoms may be prepared so that the concentration is usually 0.1 to 10 mol / L, preferably 0.1 to 5 mol / L, and the target pH is usually 3 to 8, preferably 4.5 to 6.5. More specifically, in the case of a citrate buffer, the concentration is usually 0.1 to 10 mol / L, preferably 0.1 to 5 mol / L, and the target pH is usually 3 to 8, preferably 4.5 to 6.5.

[0023] The citrate buffer solution can be prepared by a known method. For example, a 0.1 mol / L citrate buffer solution having a pH of 5 can be prepared by mixing 35 mL of 0.1 mol / L citric acid and 65 mL of 0.1 mol / L sodium citrate, but is not limited thereto.

[0024] The content (number of moles) of carboxylate ions in the emulsion cosmetic of the present invention is usually 0.5 to 10 mmol, preferably 1 to 10 mmol, and more preferably 1 to 8 mmol. More specifically, the content (number of moles) of citrate ions in the emulsion cosmetic of the present invention is usually 0.5 to 10 mmol, preferably 1 to 10 mmol, and more preferably 1 to 8 mmol. For example, with regard to a citrate buffer solution, the components may be mixed as a citrate buffer solution, or the components constituting the citrate buffer solution, such as citric acid and sodium citrate, may be mixed separately.

[0025] The pH of the emulsion cosmetic of the present invention is usually 3 to 8, preferably 4.5 to 7.5, and more preferably 4.5 to 6.5. The pH of the emulsion cosmetic of the present invention can be measured by the glass electrode method in accordance with the provisions of Japanese Industrial Standards (JIS) Z 8802:2011, the Japanese Pharmacopoeia, Seventeenth Edition, General Test Methods, 2.54 pH Test Method, and the like.

[0026] The emulsion-type cosmetic of the present invention may further contain (E) a polyglycerol fatty acid ester. The polyglycerol fatty acid ester contained as component (E) is an ester of a glycerol polymer and a fatty acid. For the purposes of the present invention, hydrophilic polyglycerol fatty acid esters such as monoesters of polyglycerol having an average degree of polymerization of glycerol of about 6 to 10 and fatty acids having about 12 to 18 carbon atoms are preferred, and polyglycerol fatty acid esters with an HLB (Hydrophilic-Lipophilic Balance) value of 14 to 17 are more preferred. Examples of such polyglycerol fatty acid esters include decaglyceryl monolaurate, decaglyceryl monomyristate, and decaglyceryl monostearate, with decaglyceryl monolaurate being preferred. In the emulsion-type cosmetic of the present invention, one type of polyglycerol fatty acid ester can be used alone, or two or more types can be used in combination.

[0027] In the present invention, the polyglycerol fatty acid esters described above can be chemically synthesized according to known production methods, or commercially available products provided by various companies can also be used. The content of component (E) in the emulsion cosmetic of the present invention is usually 0.01 to 10% by weight, preferably 0.05 to 5% by weight, and more preferably 0.1 to 3% by weight, based on the total weight of the emulsion cosmetic.

[0028] In the emulsion cosmetic of the present invention, the ratio of the content of component (B) to component (A), i.e., (A):(B), is typically 1:0.0025 to 100 by weight, preferably 1:0.01 to 10, and more preferably 1:0.05 to 3. In the emulsion cosmetic of the present invention, the ratio of the content of component (C) to component (A), i.e., (A):(C), is typically 1:0.025 to 200 by weight, preferably 1:0.1 to 20, and more preferably 1:0.2 to 8. In the emulsion cosmetic of the present invention, the ratio of the content of component (E) to component (A), i.e., (A):(E), is typically 1:0.0005 to 100 by weight, preferably 1:0.005 to 10, and more preferably 1:0.01 to 3.

[0029] The emulsion cosmetic of the present invention may contain, in addition to the above-mentioned components (A) to (E), general additives that are added to external skin preparations and cosmetics, as long as the characteristics of the present invention are not impaired.Such additives include hydrophilic solvents such as water, polyhydric alcohols other than (C), and lower alcohols (ethanol, isopropanol, etc.); hydrophilic bases such as gelatin and polyethylene glycol; animal and vegetable oils and fats (olive oil, soybean oil, camellia oil, sesame oil, peanut oil, cacao butter, beef tallow, lard, etc.), waxes (carnauba wax, beeswax, jojoba oil, etc.), aliphatic alcohols (octyldodecanol, cetanol, stearyl alcohol, etc.), fatty acids (oleic acid, palmitic acid, stearic acid, etc.), hydrocarbon oils (squalane, white wax, oily bases such as serine, liquid paraffin, ceresin, microcrystalline wax, etc.; suspending agents such as propylene glycol alginate, sodium dioctyl sulfosuccinate, povidone, etc.; polyoxyethylene hydrogenated castor oil, polyoxyethylene alkyl ethers (polyoxyethylene oleyl ether, etc.), polyoxyethylene sorbitan fatty acid esters (polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, etc.) surfactants or emulsifiers other than lecithin and polyglycerin fatty acid esters, such as glyceryl monostearate (glyceryl monostearate), sucrose fatty acid esters; thickeners such as carboxyvinyl polymers, sodium polyacrylate, xanthan gum, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol (partially saponified), etc.; stabilizers such as sodium edetate, sorbitol, thymol, polyoxyethylene polyoxypropylene glycol, etc.; antioxidants such as ascorbic acid, sodium erythorbate, tocopherol acetate, dibutylhydroxytoluene, etc.; preservatives (preservatives) such as sorbic acid, sodium dehydroacetate, methyl parahydroxybenzoate, propyl parahydroxybenzoate, butyl parahydroxybenzoate, phenoxyethanol, etc.; pH adjusters such as hydrochloric acid, acetic acid, sodium acetate, potassium hydroxide, sodium hydroxide, sodium hydrogen phosphate, etc.; skin conditioning agents (trimethylglycine, lactic acid, pyrrolidonecarboxylic acid, amino acids, salts thereof, etc.); colorants; pigments; fragrances, etc. The above additives may be used alone or in combination of two or more, as required.

[0030] The particle size (average particle size) of the emulsion particles in the emulsion cosmetic of the present invention is an indicator of emulsion stability and appearance, and represents the state of emulsification. Typically, the smaller the particle size, the more stable and transparent the emulsion cosmetic, and the more beautiful the cosmetic appearance can be provided. On the other hand, if the particle size is too small, there may be a tendency for instability. The particle size of the emulsion particles in the emulsion cosmetic of the present invention is typically 90 to 200 nm, preferably 90 to 180 nm, and more preferably 90 to 170 nm. The particle size of the emulsion particles in the emulsion cosmetic of the present invention can be measured by diluting the emulsion cosmetic with purified water as needed and measuring it at 25°C using a particle size measuring device or the like using the dynamic light scattering method.

[0031] As described above, a decrease in particle size stabilizes the emulsion, increases transparency, and improves transmittance, so the transmittance of the emulsion cosmetic of the present invention is also used as an indicator of stability and is typically 30 to 90%, preferably 35 to 90%, and more preferably 45 to 90%. The transmittance of the emulsion cosmetic of the present invention refers to the transmittance (%) of light with a wavelength of 660 nm measured at 25°C with an optical path length of 1 cm after the emulsion cosmetic is appropriately diluted with purified water as needed. The transmittance can be measured using a spectrophotometer.

[0032] The emulsion cosmetic of the present invention can be produced by a common emulsification method, for example, by warming or heating an oil phase component comprising a mixture of the above-mentioned components (A) and (B) and, if necessary, a lipophilic additive, and an aqueous phase component comprising the above-mentioned components (C) and (D), if necessary, component (E), and, if necessary, a hydrophilic additive, dissolved in water, and then stirring and mixing the oil phase component and aqueous phase component to emulsify. To obtain a fine emulsion cosmetic having the above-mentioned average particle size, it is preferable to emulsify using a high-pressure emulsifier such as a high-pressure homogenizer, microfluidizer, or ultra-high-pressure wet atomizer. The emulsion cosmetic of the present invention may be an oil-in-water emulsion cosmetic or a water-in-oil emulsion cosmetic, with oil-in-water emulsion cosmetic being preferred. The emulsion cosmetic of the present invention is in the form of a fine emulsion and can be in the form of a liquid, emulsion, paste, cream, gel, or other formulation.

[0033] Specifically, the emulsion-type cosmetic of the present invention can be suitably provided as it is as: external skin preparations in the form of emulsions, creams, etc.; skin cosmetics such as emulsions, creams, etc.; base cosmetics such as base lotions, base creams, etc.; makeup cosmetics such as emulsion foundations, cream foundations, etc.; body cosmetics such as body lotions, body creams, etc.; sunscreen cosmetics such as sunscreen emulsions, sunscreen creams, etc.; hair care cosmetics such as rinses, hair conditioners, treatments, and after-bath treatments, etc.

[0034] The emulsion cosmetic preparation of the present invention is not only excellent in emulsion stability and preservative properties, but also has a beautiful appearance, making it ideal for use as a cosmetic preparation. Therefore, the emulsion cosmetic preparation of the present invention can be used as it is as a moisturizing cosmetic preparation and even as a raw material for cosmetics.

[0035] Cosmetics containing the emulsion cosmetic of the present invention are also included in the present invention (also referred to as "cosmetics of the present invention"). That is, by adding common additives added to the above-mentioned topical skin preparations and cosmetics to the emulsion cosmetic of the present invention, the cosmetics can be suitably provided as cosmetics such as topical skin preparations in the form of emulsions, creams, etc.; skin cosmetics such as emulsions, creams, etc.; base cosmetics such as base lotions, base creams, etc.; makeup cosmetics such as emulsion foundations, cream foundations, etc.; body cosmetics such as body lotions, body creams, etc.; sunscreen cosmetics such as sunscreen emulsions, sunscreen creams, etc.; hair care cosmetics such as rinses, hair conditioners, treatments, and after-bath treatments, etc. In another embodiment, the emulsion cosmetic of the present invention can be suitably provided as a quasi-drug or pharmaceutical product by adding active ingredients and common additives to the emulsion cosmetic of the present invention.

[0036] Furthermore, the cosmetics of the present invention can be produced using known methods by simply adding the emulsion cosmetic of the present invention according to the intended use. For example, the content of the emulsion cosmetic of the present invention in the cosmetics is typically 0.1 wt% or more, preferably 0.5 wt% or more, more preferably 1 wt% or more, even more preferably 2 wt% or more, and particularly preferably 3 wt% or more, based on the total weight of the cosmetic. The upper limit is 100 wt% or less, preferably 80 wt% or less, more preferably 50 wt% or less, even more preferably 40 wt% or less, particularly preferably 30 wt% or less, even particularly preferably 20 wt% or less, and most preferably 15 wt% or less. Therefore, the contents of the components (A) to (D) and (E) of the emulsion cosmetic of the present invention in the resulting cosmetics of the present invention can be calculated taking into account the above proportions.

[0037] The cosmetic product of the present invention not only has excellent emulsion stability and antiseptic properties, but also has a beautiful appearance, making it ideal for cosmetics. In particular, the emulsion stability provides excellent moisturizing properties, allowing it to condition skin and hair due to moisture deficiency, etc. Therefore, the cosmetic product of the present invention can be used as moisturizing cosmetics such as moisturizing lotions, moisturizing emulsions, moisturizing creams, moisturizing gels, moisturizing face masks, and moisturizing packs; skin conditioning cosmetics such as skin conditioning lotions, skin conditioning emulsions, skin conditioning creams, skin conditioning gels, skin conditioning face masks, and skin conditioning packs; moisturizing hair care cosmetics such as moisturizing hair treatments and moisturizing hair conditioners; and the like.

[0038] The term "preservative effectiveness" used in this text can also be defined with reference to the 18th Edition of the Japanese Pharmacopoeia, Reference Information G4. Microorganism-related Preservative Effectiveness Test Methods <G4-3-170>. For example, when a preservative effectiveness test is conducted against bacteria selected from three types of bacteria, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, and two types of fungi, Candida albicans and Aspergillus niger, it means that the product exhibits preservative effectiveness that meets the criteria for Category IA preparations (parenteral preparations including injections and eye drops, ear drops, and nasal drops) set forth in the same method. That is, it means that the following is met: [Bacteria] After 7 days: A reduction of 1.0 log or more compared to the inoculated bacterial count After 14 days: A reduction of 3.0 log or more compared to the inoculated bacterial count After 28 days: No increase in bacterial count from 14 days [Fungi] After 7, 14, and 28 days: No increase in bacterial count from the inoculated bacterial count Note that the composition of this application corresponds to a preparation made with a water-soluble base, and since it is fully foreseeable that it may accidentally come into contact with the eyes during handling as a cosmetic ingredient, Category IA preparations (parenteral preparations including injections and ear drops / eye drops) according to the Japanese Pharmacopoeia have been selected.

[0039] The present invention provides a method for producing an emulsion cosmetic, comprising the steps of: homogenizing an oil phase component containing (A) and (B); adding and mixing an aqueous phase component containing (C) and (D) to the oil phase component; and emulsifying the mixture obtained in the above step under high pressure, wherein the amounts of (A) added, relative to the total weight of the emulsion cosmetic, are 0.1 to 20 wt %; (B) 0.05 to 10 wt %; and (C) 0.5 to 20 wt %, and the emulsion cosmetic has a carboxylate ion content of 0.5 to 10 mmol and a pH of 3 to 8 (hereinafter also referred to in this specification as the "production method of the present invention").

[0040] In the manufacturing method of the present invention, the amount of component (A) added relative to the total weight of the emulsion cosmetic is usually 0.1 to 20% by weight, preferably 0.5 to 10% by weight, and more preferably 1 to 10% by weight.

[0041] In the manufacturing method of the present invention, the amount of component (B) added relative to the total weight of the emulsion cosmetic is usually 0.05 to 10% by weight, preferably 0.1 to 5% by weight, and more preferably 0.5 to 3% by weight.

[0042] In the manufacturing method of the present invention, the amount of component (C) added relative to the total weight of the emulsion cosmetic is usually 0.5% by weight to 20% by weight, preferably 1% by weight to 10% by weight, more preferably 2% by weight to 8% by weight, even more preferably 2.5% by weight to 7.5% by weight, particularly preferably 3% by weight to 7.5% by weight, and most preferably 4% by weight to 7.5% by weight.

[0043] In the production method of the present invention, the content of carboxylate ions in the emulsion cosmetic of the present invention is usually 0.5 to 10 mmol, preferably 1 to 10 mmol, and more preferably 1 to 8 mmol. More specifically, the content (number of moles) of citrate ions in the emulsion cosmetic of the present invention is usually 0.5 to 10 mmol, preferably 1 to 10 mmol, and more preferably 1 to 8 mmol. For example, when a citrate buffer is added as (D), it may be added as a citrate buffer, or the components constituting the citrate buffer, such as citric acid and sodium citrate, may be added separately.

[0044] The pH of the emulsion cosmetic of the present invention is usually 3 to 8, preferably 4.5 to 7.5, and more preferably 4.5 to 6.5. In the production method of the present invention, the pH of the emulsion cosmetic is adjusted according to standard methods using component (D) and, if necessary, a pH adjuster. The pH of the emulsion cosmetic of the present invention can be measured by the glass electrode method in accordance with provisions such as Japanese Industrial Standards (JIS) Z 8802:2011 and the Japanese Pharmacopoeia, Seventeenth Edition, General Test Methods 2.54 pH Test Method.

[0045] The production method of the present invention may include a step of adding component (E) to the aqueous phase components. In the production method of the present invention, the amount of component (E) added relative to the total weight of the emulsion-type cosmetic is usually 0.01% by weight to 10% by weight, preferably 0.05% by weight to 5% by weight, and more preferably 0.1% by weight to 3% by weight.

[0046] The definitions and preferred ranges of components (A) to (E) are as described above. To obtain a uniform oil phase by mixing the oil phase components, i.e., components (A) and (B) and optional lipophilic additives, it is preferable to heat the oil phase components to about 70°C to 85°C while mixing. The aqueous phase component containing components (C), (D), and (E) and optional hydrophilic additives is also preferably heated to about 70°C to 85°C before mixing with the oil phase. The oil phase and aqueous phase are emulsified by mixing with a stirrer or the like for about 5 to 15 minutes, and then the mixture is cooled to 30°C to 50°C, preferably about 40°C. The oil phase and aqueous phase can be mixed using a conventional mixer, such as a mixer with stirring blades or a homomixer. Emulsification under high pressure is carried out using a high-pressure emulsifier, such as a high-pressure homogenizer, microfluidizer, or ultra-high-pressure wet atomizer. Emulsification under high pressure is carried out at 20°C to 90°C, preferably 20°C to 70°C, under a pressure of usually 100 MPa to 250 MPa, preferably 150 MPa to 230 MPa, and for a number of passes of usually 1 to 30, preferably 3 to 20.

[0047] The average particle size of the emulsion particles in the emulsion cosmetic obtained by the production method of the present invention is usually 90 nm to 200 nm, preferably 90 nm to 180 nm, and more preferably 90 nm to 170 nm. The transmittance of the emulsion cosmetic obtained by the production method of the present invention is usually 25 to 90%, preferably 30 to 90%, and more preferably 45 to 90%. The emulsion cosmetic obtained by the production method of the present invention has excellent emulsion stability at low and high temperatures, appearance, and preservative properties, and is able to satisfactorily exhibit the moisturizing and barrier functions of the acylamino acid ester.

[0048] The present invention also includes emulsion-type cosmetics obtained by the production method of the present invention. Such cosmetics have excellent moisturizing properties and can condition skin and hair, so they can also be used as moisturizing and skin-conditioning cosmetics.

[0049] The present invention also includes a method for producing a cosmetic product comprising a step of adding the emulsion cosmetic product of the present invention (also referred to as the method for producing the cosmetic product of the present invention). In the method for producing a cosmetic product of the present invention, the amount of the emulsion cosmetic product of the present invention added varies depending on the type and purpose of the cosmetic product, but is typically 0.1 wt% or more, preferably 0.5 wt% or more, more preferably 1 wt% or more, even more preferably 2 wt% or more, and particularly preferably 3 wt% or more, based on the total weight of the cosmetic product. The upper limit is 100 wt% or less, preferably 80 wt% or less, more preferably 50 wt% or less, even more preferably 40 wt% or less, particularly preferably 30 wt% or less, even particularly preferably 20 wt% or less, and most preferably 15 wt% or less. Other definitions and preferred ranges are as described above.

[0050] The present invention also includes cosmetics obtained by the cosmetic manufacturing method of the present invention. Such cosmetics have excellent moisturizing properties and can condition skin and hair, so they can also be used as moisturizing and skin-conditioning cosmetics.

[0051] The present invention will be described in more detail below with reference to examples.

[0052] (Test Example 1) 1. Preparation of emulsion-type cosmetic preparations (1) The oil phase and aqueous phase components listed in Table 1 were each weighed and dissolved at 80°C for 10 minutes. In Table 1, blank cells corresponding to contained components indicate that the component was not contained. (2) At 70°C, the aqueous phase was added to the oil phase, while emulsifying at approximately 1,500 rpm using a disper mixer. (3) Once all components were added, the mixture was further mixed using the disper mixer for approximately 5 minutes. (4) The mixture was removed and cooled to approximately 40°C or below. (5) Using a high-pressure emulsifier (Microfluidizer M-110EH, Powrex Corporation), the mixture was emulsified under conditions of a pressure of 200 MPa (approximately 30,000 psi) and 5 passes (the inlet temperature of the emulsifier was fixed at 35-40°C). (6) The emulsion was suction-filtered at room temperature using a cellulose ester filter to obtain an emulsion-type cosmetic preparation.

[0053] 2. Particle size (average particle size) (1) Sample preparation: A sample was prepared by diluting an emulsion-type cosmetic that had been returned to room temperature with MilliQ water to 1% by weight. (2) Measurement method: A measurement sample was filled into a PMMA cell, and measurements were taken at 25°C and 70 cumulative times using a measuring device (ELS-Z2: Otsuka Electronics). The obtained measured values ​​were judged according to the following criteria. (3) Judgment criteria: △: 180 nm or more 〇: 170 nm or more and less than 180 nm ◎: Less than 170 nm

[0054] 3. Transmittance (1) Sample preparation: A sample was prepared by diluting an emulsion-type cosmetic that had been returned to room temperature with MilliQ water to 1% by weight. (2) Measurement method: A PMMA cell was filled with the measurement sample, and the transmittance of light with a wavelength of 660 nm was measured at 25°C and an optical path length of 1 cm using a spectrophotometer (SHIMADZU UV-1900). The obtained measured values ​​were judged according to the following criteria. (3) Judgment criteria: △: Less than 30% ○: 30% or more and less than 45% ◎: 45% or more

[0055] 4. High-Temperature Stability (1) Sample Preparation: A 20 mL PET container was filled approximately 60-70% with emulsion-type cosmetics, and the samples were stored in a thermostatic chamber at 70°C for 14 days before being used for testing. (2) Evaluation and Measurement Method: The appearance (solution state) of the emulsion-type cosmetics was visually observed by one expert panelist, and the high-temperature stability was evaluated according to the following evaluation criteria. The pH of the sample at 70°C was measured with a pH meter (F-52, Horiba, Ltd.). (3) Evaluation Criteria: ◯: The pH decrease before and after the test was less than 0.5, and no change in appearance or properties was observed. ×: The pH decrease before and after the test was 0.5 or more, separation, or other changes in properties were observed.

[0056] 5. Low-Temperature Stability (1) Sample Preparation: A 20 mL PET container was filled with the sample to approximately 60-70%, and the sample was stored in a thermostatic chamber at -5°C for 14 days before being used for testing. (2) Evaluation and Measurement Method: The appearance (solution state) was visually observed by one expert panelist, and the low-temperature stability was evaluated according to the following evaluation criteria. The sample was diluted to 1% by weight with MilliQ water, and the transmittance at 25°C of the diluted solution was measured using a spectrophotometer (SHIMADZU UV-1900) with an optical path length of 1 cm and a wavelength of 660 nm. (3) Evaluation Criteria: ◯: The change in transmittance before and after the test is less than 10%, and no change in appearance or properties is observed. ×: The change in transmittance before and after the test is 10% or more, or solidification or separation occurs.

[0057]

[0058] 6. Results As shown in Table 1, the compositions containing citrate buffer and pentylene glycol (2A, 7A, 10A) were excellent in physical properties such as particle size and transmittance, as well as stability. Compositions that did not contain citrate buffer either experienced pH changes at high temperatures or had inferior physical properties compared to the other compositions. On the other hand, compositions that contained citrate buffer but contained 1,2-hexanediol instead of pentylene glycol solidified at low temperatures. Furthermore, when acetate buffer, citric acid aqueous solution, sodium dihydrogen phosphate aqueous solution, or acetic acid aqueous solution was used instead of citrate buffer, it was not possible to achieve both the required physical properties and stability.

[0059] The above results demonstrate that emulsion stability is improved in emulsion-type cosmetics containing components (A) to (D) and in emulsion-type cosmetics further containing component (E).

[0060] (Test Example 2) 1. Sample Preparation Test samples were prepared by mixing the components listed in Table 2 according to the methods (1) to (3) of Test Example 1. In Table 1, blank spaces corresponding to contained components indicate that the component was not contained.

[0061] 2. Antiseptic properties (based on the 18th edition of the Japanese Pharmacopoeia) (1) Test bacteria: Escherichia coli NBRC 3972 (E. coli) (Ec in the table) Staphylococcus aureus NBRC 13276 (S. aureus) (Sa in the table) (2) Preparation of test bacteria solution: Each test bacteria was pre-cultured on SCD agar medium at 32.5°C for 20 hours. The cultured bacteria were scraped with a platinum loop and suspended in sterilized physiological saline. ８ (3) Inoculation and storage of bacteria: 20 g of a specimen for each test bacteria was placed in a sterile vial, and 0.15 mL of the test bacteria solution (10 per 1 g of specimen) was added. ５ ~10 ６ Each was stored at 22.5°C, and the viable cell count was measured on the 7th, 14th, 21st, and 28th days. (4) Measurement of viable cell count: SCDLP agar medium pour plate method. (5) Evaluation criteria ◎: 10 1 Less than 10 1 10 pieces or more 3 Less than 10 3 pcs or more

[0062]

[0063] 3. Results As shown in Table 2, the composition containing both pentylene glycol and a citrate buffer solution exhibited the best preservative efficacy compared to the composition containing a polyol other than pentylene glycol, the composition containing pentylene glycol but not a citrate buffer solution, and the composition containing no polyol.

[0064] (Test Example 3) 1. Preparation of emulsion-type cosmetic preparations Compositions 2A and 1C were prepared using the same preparation method as in Test Example 1, with the formulations shown in Table 3. A "-" in the column corresponding to each component indicates that the component is not included. The same applies below. Composition 2C was prepared using the formulations shown in Table 3, according to preparation methods (1) to (4) shown in Test 1 (high-pressure emulsification was not performed).

[0065] 2. Sensory evaluation of hair 1% by weight diluted solutions of Compositions 2A, 1C, and 2C were prepared, and a hair bundle washed with an aqueous SLES solution (10% by weight) was immersed in the diluted solutions for 1 minute. After straightening the hair flow with a comb and drying overnight, five expert panelists evaluated the smoothness, silkiness, moisturizing feel, and manageability of the hair on a 7-point scale according to the following criteria, and the average score was calculated and judged.

[0066] 3. Evaluation criteria 7 points: Very good 6 points: Good 5 points: Fair 4 points: Average 3 points: Fair 2 points: Poor 1 point: Very poor

[0067] 4. Judgment criteria A: Average score of 5 or more B: Average score of 4 or more but less than 5 C: Average score of 3 or more but less than 4 D: Average score less than 3

[0068] 5. Particle size (average particle size) (1) Sample preparation: A sample was prepared by diluting the emulsion cosmetic, which had been returned to room temperature, with MilliQ water to 1% by weight. (2) Measurement method: A PMMA cell was filled with the measurement sample, and measurements were taken at 25°C and 70 cumulative times using a measuring device (ELS-Z2: Otsuka Electronics). Note that 1C was not measured because no emulsified droplets were present. Furthermore, 2C could not be measured because the particle size was too large.

[0069] 6. Results As shown in Table 3, composition 2A of the present invention was superior in the effect of improving hair smoothness and moisturizing feeling while suppressing stickiness compared to composition 1C which did not contain di(phytosteryl / octyldodecyl) lauroyl glutamate and composition 2C which was not subjected to high-pressure emulsification.

[0070]

[0071] (Formulation Example 1) Lotion 1. Preparation of Lotion A was mixed uniformly at 40°C according to the formulation shown in Table 4, and then B and C were added in that order to obtain a lotion. Composition 2A in the table refers to composition 2A used in Test Examples 1 to 3 above. Composition 2C in the table refers to composition 2C used in Test Example 3 above. PEG refers to polyethylene glycol. The same applies below.

[0072] 2. Sensory evaluation of lotion A use test was conducted by a panel of 10 expert evaluation members, who rated the smoothness upon application, ease of blending, viscosity, moist feeling after application, and non-stickiness on a 5-point scale according to the following criteria, and then calculated the average score to make a judgment.

[0073] 3. Evaluation criteria 5 points: Very good 4 points: Good 3 points: Average 2 points: Slightly poor 1 point: Poor

[0074] 4. Judgment criteria A: Average score of 4 or more B: Average score of 3.5 or more to less than 4 points C: Average score of 3 or more to less than 3.5 points D: Average score less than 3 points

[0075] 5. Results As shown in Table 4, the obtained Lotion 1 was superior to Lotion 2 in terms of moisturizing effect and non-sticky, smooth, moist feel. Furthermore, in the evaluation by one expert evaluation panelist, Lotion 1 was also superior to Lotion 3 in terms of moisturizing effect and non-sticky, smooth, moist feel ("-" in the evaluation items in the table indicates that no evaluation on a 5-point scale by the 10 expert evaluation panelists was performed).

[0076]

[0077] (Formulation Example 2) Lotion A was mixed uniformly at 40°C according to the formulation shown in Table 5, and then B and C were added in that order to obtain a lotion. The obtained lotion 4 was superior to lotions 5 and 6 in terms of moisturizing effect and a smooth, moist feel without stickiness.

[0078]

[0079] (Formulation Example 3) Cream cosmetic In accordance with the formulation shown in Table 6, A and B were each heated to 80°C and dissolved, and then B was added to A while stirring. The mixture was emulsified using a homomixer (3000 rpm, 80°C, 10 minutes) and cooled to room temperature to obtain a cream cosmetic. In the table, BG represents 1,3-butylene glycol. Compared to cream cosmetics 2 and 3, the obtained cream cosmetic 1 had a moist feel and was superior in improving skin condition.

[0080]

[0081] (Formulation Example 4) Skin Cream According to the formulation shown in Table 7, A and B were uniformly mixed and dissolved at 80°C, and then B was added to A while emulsifying using a homomixer (3000 rpm, 80°C, 6 minutes). After cooling to room temperature, C was added to obtain a skin cream. PG stearate represents an ester of stearic acid and propylene glycol. The obtained skin cream 1 was superior to skin creams 2 and 3 in terms of rich feel and skin condition improving effect.

[0082]

[0083] (Formulation Example 5) Gel Cosmetic A, B, and C were mixed uniformly at room temperature according to the formulation shown in Table 8, and then B and C were added to A while emulsifying using a homomixer (6000 rpm, 75°C). D, E, and F were added to this composition in that order to obtain a gel cosmetic. PCA stands for pyrrolidone carboxylic acid. The resulting gel cosmetic 1 was superior to gel cosmetics 2 and 3 in terms of moisturizing feel and fresh sensation upon use.

[0084]

[0085] (Formulation Example 6) Face Mask Impregnating Liquid In the formulation shown in Table 9, A and B were uniformly dispersed at room temperature, then C was heated and stirred at 85°C, and B and C were added in order to A while stirring, obtaining a uniform solution (85°C). While cooling this solution, components D, E, F, and G were added in order (45°C), obtaining a face mask impregnating liquid. The obtained face mask impregnating liquid 1 had a higher moisturizing effect and was superior in skin condition improving effect compared to face mask impregnating liquids 2 and 3.

[0086]

[0087] (Formulation Example 7) Cream cosmetic 1. Preparation of cream cosmetic A and B were mixed uniformly at 80°C according to the formulation shown in Table 10, and B was added to A while emulsifying using a homomixer (5000 rpm, 80°C, 5 minutes). The mixture was allowed to cool while stirring to obtain a cream cosmetic.

[0088] 2. Long-term Use Test Subjects applied cream cosmetics A and B to their right and left cheeks twice a day, morning and night, for two weeks, and the moisture content of the stratum corneum was measured before and two weeks after application (cream cosmetic C was not measured). The moisture content of the stratum corneum was measured as follows: Subjects entered a constant temperature and humidity room (temperature 21°C, humidity 40%), washed both cheeks (test sites) with cleansing oil, and allowed to acclimate for 30 minutes. After acclimatization, the capacitance value (initial value) of the test site (2 cm x 2 cm) was measured using a Corneometer CM825 (manufactured by Courage+Khazaka). The capacitance value measured by the Corneometer was calculated as the average of 10 measurements for each site.

[0089] 3. Judgment criteria A: The rate of change in capacitance value is +10% or more B: The rate of change in capacitance value is in the range of +3% or more to less than +10% C: The rate of change in capacitance value is in the range of -3% or more to less than +3% D: The rate of change in capacitance value is less than -3%

[0090] 4. Results Compared to Cream Cosmetic Preparation B, the obtained Cream Cosmetic Preparation A had a smooth and moist feel and was superior in improving the skin condition.

[0091]

[0092] (Formulation Example 8) Hair Treatment According to the formulation shown in Table 11, A and B were mixed and dissolved, and B was added to A while emulsifying using a homomixer (4000 rpm, 80°C, 3 minutes). The mixture was allowed to cool while stirring, and C was added to obtain a hair treatment. PG stands for propylene glycol. Compared to hair treatments 2 and 3, the resulting hair treatment 1 was superior in terms of hair conditioning effect, feel during use, and hair condition improvement effect.

[0093]

[0094] According to the present invention, it is possible to provide an emulsion-type cosmetic containing an acylamino acid ester, which is excellent in both emulsion stability and preservative properties. According to the present invention, it is possible to provide an emulsion-type cosmetic containing no or only a small amount of preservatives.

[0095] This application is based on patent applications Nos. 2024-044252 and 2024-124987 filed in Japan, the contents of which are incorporated in their entirety herein.

Claims

1. An emulsion-type cosmetic comprising (A) an acyl amino acid ester, (B) lecithin, (C) a polyhydric alcohol having 5 or less carbon atoms, and (D) a buffer solution containing a carboxylic acid having 3 or more carbon atoms, wherein the emulsion-type cosmetic contains 0.1-20 wt% of (A), 0.05-10 wt% of (B), and 0.5-20 wt% of (C) based on the total weight of the emulsion-type cosmetic, and the emulsion-type cosmetic has a carboxylate ion content of 0.5-10 mmol and a pH of 3-8.

2. The emulsion-type cosmetic preparation according to claim 1, wherein (A) the acyl amino acid ester is N-lauroyl-L-glutamic acid di(phytosteryl / 2-octyldodecyl)ester.

3. An emulsion-type cosmetic according to claim 1 or 2, wherein (C) the polyhydric alcohol having 5 or less carbon atoms is pentylene glycol.

4. An emulsion-type cosmetic according to claim 1 or 2, wherein (D) the carboxylic acid having 3 or more carbon atoms is citric acid.

5. An emulsion-type cosmetic preparation according to claim 1 or 2, wherein (B) lecithin is hydrogenated lecithin.

6. The emulsion-type cosmetic preparation according to claim 1 or 2, further comprising (E) a polyglycerin fatty acid ester.

7. The emulsion-type cosmetic preparation according to claim 2, wherein (A) further contains N-lauroyl-L-glutamic acid di(phytosteryl / octyldodecyl / behenyl).

8. The emulsion cosmetic according to claim 1 or 2, wherein the emulsion particles have an average particle size of 90 to 200 nm.

9. A cosmetic comprising the emulsion cosmetic composition according to claim 1 or 2.

10. A method for producing an emulsion-type cosmetic, comprising the steps of: homogenizing an oil phase component containing (A) an acylamino acid ester and (B) lecithin; adding and mixing an aqueous phase component containing (C) a polyhydric alcohol having 5 or fewer carbon atoms and (D) a buffer solution containing a carboxylic acid having 3 or more carbon atoms to the oil phase component; and emulsifying the mixture obtained in the above step under high pressure, wherein the amounts added relative to the total weight of the emulsion-type cosmetic are 0.1-20 wt% for (A), 0.05-10 wt% for (B), and 0.5-20 wt% for (C), and the emulsion-type cosmetic has a carboxylate ion content of 0.5-10 mmol and a pH of 3-8.

11. The method according to claim 10, wherein (A) the acyl amino acid ester is di(phytosteryl / 2-octyldodecyl) N-lauroyl-L-glutamate.

12. The method of claim 10 or 11, wherein (C) the polyhydric alcohol having 5 or less carbon atoms is pentylene glycol.

13. The method of claim 10 or 11, wherein (D) the carboxylic acid having 3 or more carbon atoms is citric acid.

14. The method of claim 10 or 11, wherein the lecithin (B) is hydrogenated lecithin.

15. The method of claim 10 or 11, further comprising the step of adding (E) a polyglycerol fatty acid ester to the aqueous phase component.

16. The method of claim 11, wherein (A) further comprises di(phytosteryl / octyldodecyl / behenyl) N-lauroyl-L-glutamate.

17. The manufacturing method according to claim 10 or 11, wherein the emulsion particles of the emulsion cosmetic have an average particle size of 90 to 200 nm.

18. A method for producing cosmetics, comprising the step of adding the emulsion cosmetic preparation according to claim 1 or 2.

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