JP5134197B2 - Oil-in-water microemulsion and process for producing the same - Google Patents

Description

  The present invention relates to an oil-in-water microemulsion and a method for producing the same.

  Emulsion preparations are frequently used in the fields of pharmaceuticals, cosmetics, foods and the like. Two-phase emulsions used in emulsion formulations include water-in-oil emulsions in which the aqueous phase is dispersed in the oil phase and oil-in-water emulsions in which the oil phase is dispersed in the aqueous phase. Is mentioned.

  As an oil-in-water emulsion for cosmetic use, for example, the one described in Patent Document 1 is known. According to this Patent Document 1, with the intention of providing an oil-in-water emulsified cosmetic that gives a moist feel without sticking to the skin, is highly effective in improving the firmness of the skin, and has excellent storage stability. (A) Oleic acid type nonionic surfactant 0.01-5 mass%, (B) Anionic surfactant 0.001-1 mass%, and (C) Water-containing oil agent 0.01-5 mass% are contained. In addition, an oil-in-water emulsified cosmetic characterized in that the mass ratio of the component (A) and the component (C) is (A) / (C) = 1 to 500 has been proposed.

By the way, as emulsion formulations, those in the form of microemulsions are strongly demanded particularly from the viewpoint of transparency or translucency of appearance and fineness of granular phases (particles).
JP 2003-286126 A

  Anionic surfactants are generally known to be irritating to human skin. Therefore, in the emulsion described in Patent Document 1 using an anionic surfactant, irritation to human skin is not sufficiently suppressed.

  In addition, since oleic acid-based nonionic surfactant has an oleic acid-based nonionic surfactant having a carbon-carbon double bond as an essential component, its odor is generally not preferred, and a patent containing the surfactant The emulsion described in Document 1 emits an unpleasant odor. Furthermore, the emulsion described in Patent Document 1 is inferior in stability over time.

  Therefore, the present invention has been made in view of the above circumstances, an oil-in-water microemulsion in which skin irritation is sufficiently suppressed, generation of unpleasant odor is sufficiently prevented, and storage stability is sufficiently excellent. The purpose is to provide.

  As a result of intensive studies to achieve the above object, the present inventors have solved the above problem by blending a specific component into the oil phase in an oil-in-water emulsion system using a specific surfactant. The present inventors have found that this can be done and have completed the present invention.

In the present invention, a surfactant mainly composed of a polyglycerin fatty acid ester having no carbon-carbon unsaturated bond in the molecule is blended, and the oil phase is a glycerin fatty acid ester dicarboxylic acid condensate and / or an acyl glutamic acid ester. A nonionic interface having an anionic surfactant and an oleic acid residue, wherein both the oil phase and the aqueous phase contain glycerin and / or 1,3-butylene glycol. It contains no activator, and the polyglycerin fatty acid ester has an HLB value of 10 to 17, and the surfactant contains more than 30% by mass of polyglycerin fatty acid ester with respect to the total amount of surfactant. An oil-in-water microemulsion is provided. Here, the “microemulsion” in the present invention refers to an emulsion in which the average particle size of the phase dispersed in a granular form is less than 200 μm in average particle size derived using a dynamic light scattering method at 25 ° C. means.

  In this oil-in-water microemulsion, since the main component of the surfactant is a polyglycerin fatty acid ester that is less irritating to human skin, skin irritation is sufficiently suppressed. In addition to using polyglycerin fatty acid ester as a surfactant, the oil phase contains a glycerin fatty acid ester dicarboxylic acid condensate and / or an acyl glutamate, and glycerin and / or both in the oil phase and the aqueous phase. By adding 1,3-butylene glycol, a microemulsion having the above average particle diameter can be obtained without using an animal-derived oil phase component. Such oil-in-water microemulsions can achieve a moist feeling when used for cosmetics.

  In addition, the oil-in-water microemulsion of the present invention has polyglycerin fatty acid ester as a main component of a surfactant and does not have an oleic acid-based nonionic surfactant as an essential component, and thus generally generates an unpleasant odor. hard. Moreover, even if it preserve | saves for a long time, coalescence of an emulsion is suppressed and it is fully excellent in storage stability. As a result, when used in cosmetics, a moist feeling of use is maintained over a long period of time.

  In the oil-in-water microemulsion of the present invention, it is preferable that the surfactant does not contain an anionic surfactant and an oleic acid nonionic surfactant because the above-described effects of the present invention can be more effectively exhibited. . Further, in the oil-in-water microemulsion of the present invention, when the acyl glutamate is N-lauroyl-L-glutamate di (phytosteryl · 2-octyl), the above-mentioned effects of the present invention can be more reliably exhibited. preferable.

  The oil-in-water microemulsion of the present invention preferably contains 0.5 to 10% by mass of an oil phase. By adjusting the blending ratio of the oil phase within this numerical range, the average particle diameter of the oil phase can be further reduced. Moreover, it is preferable to contain 1.0-10 mass% of specific oil content with respect to the total amount of an oil phase from the same viewpoint.

The present invention relates to a method for producing an oil-in-water microemulsion comprising a polyglycerin fatty acid ester as a main component of a surfactant, a specific oil comprising a glycerin fatty acid ester dicarboxylic acid condensate and / or an acyl glutamic acid ester, and the oil phase containing glycerin and / or 1,3-butylene glycol, have a step of adding the aqueous phase containing glycerin and / or 1,3-butylene glycol, surfactant anionic surfactant and It does not contain a nonionic surfactant having an oleic acid residue, the polyglycerin fatty acid ester has an HLB value of 10 to 17, and the surfactant is a polybasic surfactant with respect to the total amount of surfactant. Made in the oil-in-water microemulsion glycerol fatty acid esters are those containing more than 30 wt% To provide a method. According to this production method, the above-described oil-in-water microemulsion of the present invention can be obtained sufficiently reliably.

  According to the present invention, it is possible to provide an oil-in-water microemulsion in which skin irritation is sufficiently suppressed, unpleasant odor is sufficiently prevented, and storage stability is sufficiently excellent.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  In the oil-in-water microemulsion of this embodiment, a surfactant mainly composed of polyglycerin fatty acid ester having no carbon-carbon unsaturated bond in the molecule is blended, and the oil phase is glycerin fatty acid ester dicarboxylic acid. It contains a specific oil composed of a condensate and / or an acyl glutamate, and both the oil phase and the aqueous phase contain glycerin and / or 1,3-butylene glycol. Hereinafter, each component which comprises the oil-in-water microemulsion of this embodiment is demonstrated.

  The surfactant in the present embodiment is preferably blended in the oil phase, and contains a polyglycerol fatty acid ester as a main component. The polyglycerol fatty acid ester is not particularly limited as long as it does not have a carbon-carbon unsaturated bond in the molecule. Examples of such polyglycerol fatty acid esters include tetraglycerol monolaurate, pentaglycerol monolaurate, hexaglycerol monolaurate, decaglycerol monolaurate, hexaglycerol monomyristate, decaglycerol monomyristate, hexaglycerol. Monopalmitate, Hexaglycerol monostearate, Hexaglycerol sesquistearate, Decaglycerol monostearate, Decaglycerol distearate, Decaglycerol tristearate, Hexaglycerol monoisostearate, Decaglycerol monoisostearate Acid ester, decaglycerin diisostearate ester , It includes decaglycerol mono capric acid ester.

  Among these polyglycerin fatty acid esters, one or more polyglycerin fatty acid esters selected from the group consisting of pentaglycerin monolaurate and hexaglycerin monostearate are used from the viewpoint of more reliably exerting the effects of the present invention. Preferably, pentaglycerin monolaurate is more preferable. The polyglycerin fatty acid ester may be synthesized by a conventional method, or a commercially available product may be obtained.

  The polyglycerin fatty acid ester preferably has an HLB value of 10 to 17 in order to obtain a more stable microemulsion.

  The polyglycerol fatty acid ester which does not have a carbon-carbon unsaturated bond in a molecule | numerator is used individually by 1 type or in combination of 2 or more types.

  As the surfactant according to the present embodiment, an anionic surfactant may be blended to such an extent that the object of the present invention is not impaired, but in order to achieve the object of the present invention more reliably, an anionic surfactant is used. Most preferably, no agent is blended.

  Further, from the viewpoint of further improving the temporal stability of the microemulsion of the present embodiment and suppressing the generation of an unpleasant odor, it is most preferable not to add an oleic acid nonionic surfactant as a surfactant.

  In the oil-in-water microemulsion of the present embodiment, the blending ratio of the polyglycerol fatty acid ester having no carbon-carbon unsaturated bond in the molecule with respect to the total amount of the surfactant is preferably more than 30% by mass, and 50% by mass. % Or more is more preferable. When the blending ratio of the polyglycerin fatty acid ester is within such a numerical range, the object of the present invention can be achieved more efficiently and reliably, and the effects of the present invention can be achieved more effectively.

  The specific oil contained in the oil phase in the present embodiment is a glycerin fatty acid ester dicarboxylic acid condensate and / or an acyl glutamate.

  The glycerin fatty acid ester dicarboxylic acid condensate in the oil phase may be a monoglycerin fatty acid ester dicarboxylic acid condensate or a diglycerin fatty acid ester dicarboxylic acid condensate. This glycerin fatty acid ester dicarboxylic acid condensate is obtained by esterifying a mixed fatty acid composed of an aliphatic dicarboxylic acid, a higher linear aliphatic monocarboxylic acid and a higher branched aliphatic monocarboxylic acid with monoglycerin or diglycerin by a known method. Obtained. As a method for esterification, an esterification reaction may be used in the absence of a catalyst or in the presence of a catalyst under normal pressure or reduced pressure. In this case, after completion of the esterification reaction, the reaction mixture may be subjected to alkali deoxidation, decolorization with a decoloring agent, and then deodorized and purified by steam distillation according to a conventional method.

  Alternatively, a commercially available glycerin fatty acid ester dicarboxylic acid condensate may be obtained and used.

  Examples of the aliphatic dicarboxylic acid include saturated aliphatic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonamethylene dicarboxylic acid, and decamethylene dicarboxylic acid. Examples thereof include unsaturated aliphatic dicarboxylic acids such as dicarboxylic acid, itaconic acid, maleic acid, fumaric acid and muconic acid. Among these, at least one dicarboxylic acid selected from the group consisting of adipic acid, azelaic acid and sebacic acid is particularly preferable, and adipic acid is more preferable. These aliphatic dicarboxylic acids are used singly or in combination of two or more.

  As the higher linear aliphatic monocarboxylic acid, a linear saturated fatty acid is preferable, and a fatty acid having 8 or more carbon atoms is more preferable. Specifically, for example, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, nonadecanoic acid, arachic acid, heneicosanoic acid, behenic acid Examples include acids, tricosanoic acid, and lignoceric acid. Among these, one or more fatty acids selected from the group consisting of caprylic acid, capric acid and stearic acid are preferable from the viewpoint of more reliably achieving the object of the present invention. These higher linear aliphatic monocarboxylic acids are used alone or in combination of two or more.

  The higher branched aliphatic monocarboxylic acid preferably has 6 or more carbon atoms and one or more branched chains. Specific examples include 2-ethylpentanoic acid, 2-ethylhexanoic acid, neotridecanoic acid, and isostearic acid. Among these, 2-ethylhexanoic acid and / or isostearic acid are preferable from the viewpoint of more reliably achieving the object of the present invention. These higher branched aliphatic monocarboxylic acids are used alone or in combination of two or more.

  The aliphatic dicarboxylic acid, higher linear aliphatic monocarboxylic acid and higher branched aliphatic monocarboxylic acid may be used in combination with any of those described above.

  Moreover, the fatty acid which is a raw material of the glycerin fatty acid ester dicarboxylic acid condensate, for example, a part of the higher linear aliphatic monocarboxylic acid, may be obtained by substituting a part of hydrogen atoms with a hydroxyl group.

  The glycerin fatty acid ester dicarboxylic acid condensate is used singly or in combination of two or more.

  Examples of the acyl glutamate in the oil phase include dioctyldodecyl lauroyl glutamate, di (N-lauroyl-L-glutamate) (cholesteryl behenyl octyldodecyl), di-N-lauroyl-L-glutamate (phytosteryl behenyl octyldodecyl) And lauroyl glutamate such as N-lauroyl-L-glutamate di (phytosteryl · 2-octyl). Among these, from the viewpoint of achieving the object of the present invention more reliably, lauroyl glutamate is preferable, and N-lauroyl-L-glutamate di (phytosteryl · 2-octyl) is more preferable.

  The acyl glutamate ester may be synthesized by a conventional method, or a commercially available product may be obtained. Moreover, acyl glutamate ester is used individually by 1 type or in combination of 2 or more types.

  The above-mentioned specific oil is preferably contained in an amount of 1.0 to 10% by mass with respect to the total amount of the oil phase. Even if the content ratio of the specific oil is less than 1.0% by mass or more than 10% by mass, the average particle size of the oil phase tends to be too large to form a microemulsion. .

  From the viewpoint of making the emulsion stability of the microemulsion sufficiently high, glycerin and / or 1,3-butylene glycol is blended in the oil phase and the aqueous phase.

  In this embodiment, the components used in the oil phase other than those described above include, for example, avocado oil, almond oil, olive oil, macadamia nut oil, castor oil, camellia oil, jojoba oil, sesame oil, safflower oil, large Vegetable oil such as bean oil, persic oil, cottonseed oil, sunflower oil, linseed oil, cacao butter, coconut butter, molasses, carnauba wax, candelilla wax, hardened oils, liquid paraffin, petrolatum, isoparaffin, ceresin, squalane, squalene, etc. Hydrocarbon oils, lauryl alcohol, cetanol, stearyl alcohol, lanolin alcohol, hydrogenated lanolin alcohol, hexyl decanol, octyldodecanol and other higher alcohols, dimethylpolysiloxane, methylphenylpolysiloxane and other silicone oils, paraffin, micro Hydrocarbon waxes such as Lister phosphorus wax. Among these, it is preferable to contain one or more nonpolar oils selected from the group consisting of hydrocarbon oils and silicone oils in order to obtain a light and light feeling. The above-mentioned oils are used alone or in combination of two or more.

  When the oil phase contains one or more nonpolar oils selected from the group consisting of hydrocarbon oils and silicone oils in addition to the specific oils described above, the specific oils described above are the total amount of the specific oils and the nonpolar oils. It is preferable that 1 to 10% by mass is contained. When the content ratio of the specific oil is less than 1.0% by mass, the characteristics of the present invention in the feeling of use tend to be hardly exhibited, and when it exceeds 10% by mass, the average particle size of the oil phase becomes too large. , It tends to be difficult to form microemulsions.

  The oil-in-water microemulsion according to the present embodiment is an ester oil, a silicone derivative, a surfactant, a powder, a water-soluble solution as an “other component” other than the above-described components, as long as the purpose and effect of the present invention are not impaired. Polymers, UV absorbers, polyhydric alcohols, saccharides, moisturizers, lower alcohols, antioxidants, preservatives, enzymes such as lipases and proteases, various drugs such as resorcinol and sulfur, refreshing agents, pigments, fragrances, etc. May be blended.

  Examples of the polyhydric alcohol include propylene glycol, dipropylene glycol, ethylene glycol, diethylene glycol, polyethylene glycol, isoprene glycol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, and 2-butene. -1,4-diol, 1,5-pentanediol, diglycerin, triglycerin, polyglycerin, trimethylolpropane, erythritol, pentaerythritol, sorbitol, mabit, maltitol, lactose, fructose, maltose, sorbitan, glucose, arabitol , Xylitol and mannitol.

  The oil-in-water microemulsion of this embodiment preferably contains 0.5 to 10% by mass of the oil phase with respect to the total amount. By adjusting the blending ratio of the oil phase within this numerical range, the average particle diameter of the oil phase can be further reduced.

  The oil-in-water microemulsion of the present embodiment described above can contain any of the above components in any combination without departing from the purpose and effect of the present invention. An oil-in-water microemulsion in which preferred components are used in combination is preferable because the object of the present invention can be achieved at a higher level and the effects of the present invention can be more effectively exhibited.

  In the oil-in-water microemulsion of the present invention, the average particle size of the oil phase is made less than 200 nm by adjusting the types and blending ratios of the above-mentioned components, but can be made less than 100 nm. According to this embodiment, it is possible to keep the average particle size of the oil phase within the above range without using animal-derived components. Therefore, in this embodiment, the odor change due to the change of the content component is suppressed, the quality of the product can be maintained almost constant, the skin irritation can be lowered to ensure a higher level of safety, and the cosmetics Thus, a microemulsion capable of realizing a moist feeling when used in the process is obtained.

  Moreover, since the oil-in-water microemulsion of the present invention does not contain an anionic surfactant as an essential component, irritation to human skin can be suppressed. Furthermore, since a substance having a carbon-carbon double bond such as an oleic acid-based nonionic surfactant is not an essential component, the microemulsion has high temporal stability and maintains a fine average particle diameter of less than 200 nm for a long time. can do. Therefore, it is possible to realize a moist feeling when used in cosmetics and the like over a long period of time. In addition, since a substance having an unpleasant odor is not an essential component, the tendency to worry about the odor during storage and use of cosmetics using an oil-in-water microemulsion is reduced.

  By the way, polyglycerin fatty acid ester is inferior in solubilizing power and emulsifying power as compared with nonionic surfactants having a polyoxyalkylene chain, so that oily components such as fragrances and oil-soluble vitamins are precipitated in the product. There is a problem in the stability of the preparation that the fatty acid liberated by the hydrolysis that occurs over time or the hydrolysis that occurs with time causes white turbidity or insoluble products. However, the oil-in-water microemulsion of the present invention is extremely excellent from the viewpoint of formulation stability even when a polyglycerin fatty acid ester is used. This is accomplished by adding glycerin fatty acid ester dicarboxylic acid condensate and / or acyl glutamate to the oil phase and simultaneously adding glycerin and / or 1,3-butylene glycol to the oil and water phases. This is considered to be because the solubility and emulsifiability of glycerin fatty acid ester are improved. However, the factor is not limited to this.

  The oil-in-water microemulsion of the present invention is preferably used for a base, a cosmetic, a food emulsion in a pharmaceutical preparation such as an emulsion and an emulsion ointment. For cosmetics, lotion, multi-layer lotion, sunscreen, milk, cream, beauty essence, non-woven cloth-impregnated mask, pack, hairdressing, hair nourishing face, limbs, body basic cosmetics, foundation, eye It can be used as a makeup cosmetic such as shadow, eyeliner, mascara and the like.

  Next, the manufacturing method of the oil-in-water microemulsion of this embodiment is demonstrated. The method for producing an oil-in-water microemulsion according to this embodiment is a method for producing an oil-in-water microemulsion comprising a polyglycerin fatty acid ester as a main component of a surfactant, comprising a glycerin fatty acid ester dicarboxylic acid condensate and And / or a step of adding a specific oil component comprising an acyl glutamate ester and an oil phase containing glycerin and / or 1,3-butylene glycol to an aqueous phase containing glycerin and / or 1,3-butylene glycol. is there. More specifically, an aqueous phase preparation step for preparing an aqueous phase containing glycerin and / or 1,3-butylene glycol, and an oil phase containing the specific oil and glycerin and / or 1,3-butylene glycol are prepared. An oil phase preparation step, an oil phase addition step of adding an oil phase to the aqueous phase to obtain a mixture, and an agitation step of stirring the mixture to obtain an oil-in-water microemulsion.

  In the aqueous phase preparation step, an aqueous phase component is obtained by stirring and mixing a predetermined amount of water and the above polyol and, if necessary, other components. The stirring and mixing may be performed by dissolving the aqueous phase uniformly. For example, it is preferably performed at room temperature to 90 ° C. for about 1 to 30 minutes. In addition, in the oil phase preparation step, a predetermined amount of the specific oil and glycerin and / or 1,3-butylene glycol, preferably the nonpolar oil, and further mixed with other components as necessary to obtain an oil. A phase component is obtained. The stirring and mixing may be performed so long as the oil phase is uniformly dissolved. For example, it is preferably performed at room temperature to 90 ° C. for about 1 to 30 minutes. In the oil phase addition step, the oil phase component is added to the water phase component, and preferably preliminarily emulsified by mixing at 70 ° C. or higher, followed by a homomixer, a high-pressure homogenizer, an ultrasonic emulsifier or a colloid mill. Etc. is used to obtain the oil-in-water microemulsion according to the present embodiment.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

(Examples 1-12, Comparative Examples 1-3)
Prepare an aqueous phase component and an oil phase component each of the components shown in Tables 1 and 2 blended in the proportions (parts by mass) shown in Tables 1 and 2, and add the oil phase component to the aqueous phase component by the method described above. An oil-in-water microemulsion was prepared by stirring well. In Tables 1 and 2, glycerin fatty acid ester dicarboxylic acid condensate A is a diglycerin mixed fatty acid (caprylic acid, capric acid, isostearic acid, stearic acid, 12-hydroxystearic acid) ester adipic acid condensate, glycerin fatty acid ester dicarboxylic acid condensation Product B is monoglycerin mixed fatty acid (2-ethylhexanoic acid / stearic acid) ester adipic acid condensate, glycerin fatty acid ester dicarboxylic acid condensate C is diglycerin mixed fatty acid (isostearic acid / stearic acid) ester sebacic acid condensate, glycerin The fatty acid ester dicarboxylic acid condensate D represents a monoglycerin mixed fatty acid (caprylic acid / capric acid) ester sebacic acid condensate. Acyl glutamate E is N-lauroyl-L-glutamate di (phytosteryl 2-octyl), acyl glutamate F is N-lauroyl-L-glutamate dioctyldecyl, and acyl glutamate G is N-lauroyl-L-. Glutamate di (cholesteryl / behenyl / octyldodecyl), acyl glutamate ester H represents N-lauroyl-L-glutamate di (phytosteryl / behenyl / octyldodecyl).

  The obtained oil-in-water microemulsion was allowed to stand in an environment of 40 ° C. for one day and / or after standing for one week, and then its transmittance, pH and / or average particle size was measured. The average particle size was derived by the above method. In addition, the transmittance is obtained by putting an oil-in-water microemulsion in a quartz cell having a cell thickness of 1 cm and measuring the transmittance of visible light using a spectrophotometer (manufactured by Shimadzu Corporation, UV-160A, trade name). Derived by. The results are shown in Table 3.

  About the said Example and comparative example, the sensory evaluation of the feeling of use (moist feeling), skin irritation, and the change of an odor were investigated. Sensory evaluation of feeling of use (moist feeling) is evaluated by calculating the average value (0 to 5 points) of 10 female panelists as a group, evaluating the moist feeling when using the emulsion based on the scores shown in Table 4. did. A higher average value means a higher moist feeling. For skin irritation, a 48-hour occlusion patch test was conducted by 20 male panelists, and the skin condition after that was determined according to the two criteria (erythema and edema) shown in Table 5. The average value (0 to 4 points) was evaluated. A lower average value means lower skin irritation. As for the change in odor, three panelists specializing in fragrances evaluated whether or not fatty acid odor was observed in the emulsion after standing for one month, and the case where almost no fatty acid odor was observed was indicated as “A”, The case where the fatty acid odor was clearly recognized was designated as “B”. The above results are shown in Table 3.

In addition, in the mixing | blending of the comparative example 1, the water phase and the oil phase were completely isolate | separated and the emulsion could not be obtained. In the formulation of Comparative Example 2, coalescence of the emulsion was visually observed after standing at 40 ° C. for one week. For the above reasons, Comparative Examples 1 and 2 were not evaluated except for moist feeling.

Claims (5)

A surfactant containing a polyglycerin fatty acid ester having no carbon-carbon unsaturated bond in the molecule is blended,
The oil phase contains a specific oil consisting of a glycerin fatty acid ester dicarboxylic acid condensate and / or an acyl glutamate,
Both the oil phase and the aqueous phase contain glycerin and / or 1,3-butylene glycol ;
The surfactant does not contain an anionic surfactant and a nonionic surfactant having an oleic acid residue,
The polyglycerol fatty acid ester has an HLB value of 10 to 17,
The surfactant is an oil-in-water microemulsion containing more than 30% by mass of the polyglycerol fatty acid ester with respect to the total amount of the surfactant . The oil-in-water microemulsion according to claim 1, wherein the acyl glutamate ester is N-lauroyl-L-glutamate di (phytosteryl 2-octyl). The oil-in-water microemulsion according to claim 1 or 2 , comprising 0.5 to 10% by mass of the oil phase. The oil-in-water microemulsion according to any one of claims 1 to 3 , comprising 1.0 to 10% by mass of the specific oil with respect to the total amount of the oil phase. A manufacturing method of an oil-in-water microemulsion by blending a surfactant comprising a polyglycerol fatty acid ester,
A specific oil component comprising a glycerin fatty acid ester dicarboxylic acid condensate and / or an acyl glutamate ester and an oil phase containing glycerin and / or 1,3-butylene glycol, an aqueous phase containing glycerin and / or 1,3-butylene glycol adding, the possess to,
The surfactant does not contain an anionic surfactant and a nonionic surfactant having an oleic acid residue,
The polyglycerol fatty acid ester has an HLB value of 10 to 17,
The said surfactant is a manufacturing method of the oil-in-water microemulsion which contains more than 30 mass% of said polyglycerol fatty acid ester with respect to the total amount of the said surfactant .