CN105705129B

CN105705129B - Emulsion and method for producing same

Info

Publication number: CN105705129B
Application number: CN201480060707.XA
Authority: CN
Inventors: 龙口巌; 松冈龙雄
Original assignee: Suntory Holdings Ltd
Current assignee: Suntory Holdings Ltd
Priority date: 2013-09-06
Filing date: 2014-09-05
Publication date: 2019-12-27
Anticipated expiration: 2034-09-05
Also published as: TW201521777A; WO2015034046A1; TWI638665B; HK1222540A1; JPWO2015034046A1; CN105705129A; JP6571001B2

Abstract

The invention provides an emulsion which contains an oily component having a fine dispersed particle diameter and has good stability over time. Specifically, an O/a type emulsion in which an oily component is dispersed in a polyol phase can be obtained by mixing a fatty acid ester selected from the group consisting of a polyglycerin fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene sorbitan fatty acid ester and a mixture thereof with an acylamino acid and/or a salt thereof in a specific ratio in a polyol having 3 or more atoms, and adding the oily component thereto under stirring. The O/A emulsion is added to an aqueous medium under stirring to obtain an oil-in-water emulsion.

Description

Emulsion and method for producing same

Technical Field

The present invention relates to an emulsion in which an oily component is dispersed in a phase containing a polyhydric alcohol, an oil-in-water (O/W type) emulsion in which the emulsion is dispersed in an aqueous medium, and a method for producing the same. In particular, the present invention relates to an emulsion having a fine dispersed particle size of an oily component and having excellent stability over time even in a low viscosity system.

Background

In aqueous skin external compositions such as lotions, beauty lotions, hair tonics and the like, oil-in-water emulsions are widely used in order to incorporate oil-based active ingredients into the system. Such an aqueous composition for external use for skin may be designed to have a low viscosity in consideration of the feeling of use and ease of use. The following problems are generally encountered in oil-in-water emulsions in low viscosity formulations: the separation phenomenon due to the difference in specific gravity between the oily component and the aqueous component is likely to occur, and the stability with time is likely to deteriorate. As a technique for maintaining the stability of an emulsion in a low-viscosity preparation, an emulsion composition containing a hydrogenated lecithin and a hydrogenated lecithin at a specific mixing ratio has been reported (patent document 1).

On the other hand, it is preferable to reduce the particle diameter of the dispersed particles of the active ingredient in the composition for external application to the skin to improve the skin permeability of the active ingredient. As a method for obtaining an oil-in-water emulsion having a fine particle size, it has been reported that an oil phase is dispersed under high pressure and a water-soluble polymer is used (patent document 2).

Documents of the prior art

Patent document

Patent document 1 japanese patent application laid-open No. 2010-6739

Patent document 2, specification of japanese patent No. 4444149

Disclosure of Invention

Such an oil-in-water emulsion that can be formed into a fine dispersion particle size and is excellent in stability over time even in a low viscosity system is advantageous in a composition for external application to the skin. The technical problem to be solved by the present invention is to provide an emulsion that contains an oily component having a fine dispersed particle size and excellent skin permeability and that has good stability over time.

The present inventors have conducted intensive studies and as a result, have found that an emulsion in which an oily component is dispersed in a polyol phase can be obtained without using a special apparatus such as a high-pressure homogenizer by combining a specific fatty acid ester and an acylamino acid and/or a salt thereof in a specific ratio in a 3-membered or higher polyol and adding the oily component thereto under stirring. The dispersed particle size of the oily component in the emulsion is fine (average particle size is 1 μm or less), and the fine particle size can be maintained even after long-term storage. Further, it has been found that an oil-in-water emulsion having a fine dispersion particle size and excellent stability with time can be obtained by dispersing the emulsion in an aqueous medium. The present invention is not limited to this, and includes the following.

1. An emulsion, comprising: 50 to 97% by weight of a 3-or more-membered polyhydric alcohol,

1 to 10% by weight of a fatty acid ester selected from the group consisting of polyglycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters and mixtures thereof,

0.01 to 3 wt% of acylamino acid and/or salt thereof,

And 1 to 30 wt% of an oily component,

the oily component is dispersed in a phase comprising the polyol.

2. The emulsion according to claim 1, wherein the amount of the 3-or more-membered polyol is 80 to 97% by weight and the amount of the oily component is 1 to 18% by weight.

3. The emulsion according to 1 or 2, wherein the 3-or more-membered polyol is glycerin.

4. The emulsion according to any one of the above 1 to 3, wherein the fatty acid ester is a polyglycerin fatty acid ester.

5. The emulsion according to any one of the above 1 to 4, wherein the acylamino acid and/or salt thereof is 0.01 to 1% by weight.

6. The emulsion according to any one of the above 1 to 5, wherein the average particle diameter of the dispersed oil component is 1 μm or less.

7. An oil-in-water emulsion, which is characterized by being obtained by dispersing the emulsion according to any one of 1 to 6 in an aqueous medium.

8. The oil-in-water emulsion according to the above 7, characterized by comprising 90 to 99.5% by weight of an aqueous medium.

9. The oil-in-water emulsion according to the above 7 or 8, characterized in that the viscosity (25 ℃, 12rpm with spindle No. 1) measured by a B-type viscometer is 1000 mPas or less.

10. The oil-in-water emulsion according to any one of the above 7 to 9, wherein the average particle diameter of the dispersed oil component is 1 μm or less.

11. A cosmetic characterized by comprising the oil-in-water emulsion according to any one of 8 to 10.

12. A composition for external application to the skin, comprising the oil-in-water emulsion according to any one of the above 8 to 10.

13. A method for producing an emulsion, comprising the steps of: mixing a fatty acid ester selected from the group consisting of a polyglycerin fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene sorbitan fatty acid ester and a mixture thereof with an acylamino acid and/or a salt thereof in a liquid containing a 3-or more-membered polyhydric alcohol,

then, adding the oily component to the liquid containing the polyhydric alcohol with stirring to form an emulsion in which the oily component is dispersed in the liquid containing the polyhydric alcohol,

the acylamino acid and/or salt thereof is in an amount of 0.01 to 3 wt% based on the amount of the emulsion.

14. A method for producing an oil-in-water emulsion, comprising the steps of: mixing a fatty acid ester selected from the group consisting of a polyglycerin fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene sorbitan fatty acid ester and a mixture thereof with an acylamino acid and/or a salt thereof in a liquid containing a 3-or more-membered polyhydric alcohol,

then, the oily component is added to the liquid containing the polyhydric alcohol under stirring to form an emulsion in which the oily component is dispersed in the liquid containing the polyhydric alcohol,

subsequently, the resulting emulsion is mixed with an aqueous medium to form an oil-in-water emulsion in which an oily component is dispersed in the aqueous medium,

the acylamino acid and/or salt thereof is in an amount of 0.01 to 3 wt% based on the amount of an emulsion in which an oily component is dispersed in a liquid containing the polyhydric alcohol.

According to the present invention, an emulsion having an oil component with a fine dispersed particle size can be obtained. The emulsion of the present invention can be produced by a general stirrer having a rotor without using a device for pulverizing particles under pressure such as a high-pressure homogenizer. Even when the emulsion is produced by such a general mixer, the emulsion of the present invention can have a fine dispersed particle size having an average particle size of 1 μm or less. In the present invention, first, an emulsion in which an oily component is dispersed in a phase containing a 3-or more-membered polyol is prepared. Subsequently, the emulsion is dispersed in an aqueous medium to obtain an oil-in-water emulsion. The resulting oil-in-water emulsion retains a fine dispersion particle size and has excellent dispersion stability over time even if the viscosity is low. Further, since it is mild to the skin and gives a good feeling of use, it is suitably used for an aromatic cosmetic or a skin external composition such as a cosmetic lotion and a hair care product. Further, since the oily component has high permeability to the skin, it is particularly suitable for use in applications in which the active ingredient penetrates into the skin, for example, skin external compositions such as a cosmetic liquid and a hair-growing agent.

Drawings

Fig. 1 shows the measurement results of the average particle diameter in the stability test with time in example 3.

Fig. 2 shows the results of measurement of skin permeability in example 4.

FIG. 3 shows the results of measurement of pH and absorbance in example 5.

Detailed Description

In the present invention, first, a fatty acid ester selected from the group consisting of a polyglycerin fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene sorbitan fatty acid ester, and a mixture thereof is mixed with an acylamino acid and/or a salt thereof in a specific ratio in a polyol having 3 or more members, and an oily component is added thereto under stirring to form an emulsion in which the oily component is dispersed in a phase containing the polyol (in the present specification, the emulsion obtained at this stage is also referred to as an "O/a type emulsion"). The oily component of the resulting O/A emulsion has a fine dispersion particle size, and the average particle size can be as small as 1 μm or less. Subsequently, the O/a type emulsion is added to an aqueous medium under stirring to obtain an oil-in-water type emulsion. The obtained oil-in-water emulsion retains the fine dispersion particle size in the O/A emulsion, and can maintain stable dispersion for a long period of time even if the viscosity is low (for example, 1000 mPas or less as measured by a B-type viscometer at 25 ℃, spindle 1, and 12 rpm). The oil-in-water emulsion of the present invention can be suitably used for a cosmetic such as a cosmetic water or a hair tonic or a composition for external application to the skin.

(O/A type emulsion)

In the preparation of an O/A emulsion (an emulsion in which an oily component is dispersed in a phase containing a polyhydric alcohol), 1 to 10 wt% of a fatty acid ester selected from the group consisting of a polyglycerin fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene sorbitan fatty acid ester and a mixture thereof is mixed with 0.01 to 3 wt% of an acylamino acid and/or a salt thereof in an amount of 50 to 97 wt% of a polyhydric alcohol having 3 or more atoms based on the amount of the final O/A emulsion, and 1 to 30 wt% of the oily component is added thereto under stirring.

In the O/a type emulsion of the present invention, a phase containing a 3-or more-membered polyol is used as a continuous phase. For example, the use of a 2-membered alcohol such as 1, 3-butanediol is not preferable because the oily component is separated. Examples of the 3-or more-membered polyhydric alcohol include polyglycerols such as glycerin, diglycerin, triglycerin, and tetraglycerin, and sugar alcohols such as pentaerythritol, erythritol, xylitol, and mannitol. Among them, glycerin is preferred. There are various grades of glycerol, but any can be used. For example, a cosmetic concentrated glycerin having a glycerin content of 95.0% or more can be used.

The amount of the 3-or more-membered polyol to be used is 50 to 97% by weight, preferably 80 to 97% by weight, based on the amount of the finally obtained O/A emulsion. When the amount is less than 50% by weight, the dispersed particle size of the oily component in the obtained emulsion becomes large, and the dispersion stability is deteriorated.

Next, in the 3-or more-membered polyol, a fatty acid ester selected from the group consisting of a polyglycerin fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene sorbitan fatty acid ester, and a mixture thereof is mixed with an acylamino acid and/or a salt thereof.

The polyglycerin fatty acid ester is preferably composed of a polyglycerin having a polymerization degree of 4 to 10 and 1 or more kinds of fatty acids having 12 to 22 carbon atoms. Examples thereof include hexaglycerol monooleate, hexaglycerol monopalmitate, hexaglycerol monomyristate, hexaglycerol monolaurate, decaglycerol monooleate, decaglycerol monostearate, decaglycerol monopalmitate, decaglycerol monomyristate, and decaglycerol monolaurate. Among them, decaglycerol monofatty acid ester is preferable, and decaglycerol monomyristate is more preferable. The HLB of the polyglycerin fatty acid ester is preferably about 10 to 16.

Examples of the sorbitan fatty acid ester include sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan sesquioleate, and the like. Among them, sorbitan monostearate, sorbitan monooleate, and sorbitan sesquioleate are preferable, and sorbitan sesquioleate is more preferable.

Examples of the polyoxyethylene sorbitan fatty acid ester include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monomyristate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan tristearate, and polyoxyethylene sorbitan triisostearate. The average molar number of addition of ethylene oxide is preferably about 20, and among these, polyoxyethylene sorbitan monooleate having an average molar number of addition of ethylene oxide of 20 is preferably used.

Among the above fatty acid esters, polyglycerin fatty acid esters are most preferable. When a polyglycerol fatty acid ester is used, an emulsion having a fine dispersion particle diameter can be formed as compared with the case of using a sorbitan fatty acid ester or a polyoxyethylene sorbitan fatty acid ester.

The fatty acid ester is used in an amount of 1 to 10 wt%, preferably 1.5 to 8 wt%, more preferably 2 to 7.5 wt%, based on the amount of the finally obtained O/a emulsion. When the amount is less than 1% by weight, sufficient dispersion stability cannot be obtained, and when the amount exceeds 10% by weight, stickiness occurs and the feeling of use is deteriorated, which is not preferable.

In addition to the above-mentioned fatty acid ester, an acylamino acid and/or a salt thereof is mixed with a 3-or more-membered polyhydric alcohol. The present inventors have found that the use of an acylamino acid and/or a salt thereof can reduce the particle size of the oily component dispersed in the emulsion. As the acylamino acid and/or a salt thereof, long-chain acylglutamic acid and a salt thereof, and acylglycine and a salt thereof are excellent in safety. The fatty acid preferably has about 12 to 20 carbon atoms. Examples of the acylamino acid and/or its salt include, but are not limited to, potassium cocoyl glutamate, sodium cocoyl glutamate, triethanolamine cocoyl glutamate, potassium lauroyl glutamate, sodium lauroyl glutamate, triethanolamine lauroyl glutamate, potassium myristoyl glutamate, sodium myristoyl glutamate, potassium stearoyl glutamate, sodium stearoyl glutamate, disodium stearoyl glutamate, sodium hydrogenated tallow fatty acid acyl glutamate, sodium cocoyl-hydrogenated tallow fatty acid acyl glutamate, potassium cocoyl glycinate, sodium cocoyl glycinate, triethanolamine cocoyl glycinate, potassium lauroyl glycinate, sodium lauroyl glycinate, triethanolamine lauroyl glycinate, potassium myristoyl glycinate, sodium myristoyl glycinate, potassium stearoyl glycinate, sodium stearoyl glycinate, disodium stearoyl glycinate, sodium hydrogenated tallow glycinate, sodium lauroyl glycinate, sodium stearoyl glycin, Sodium cocoyl-hydrogenated tallow acyl glycinate, and the like.

The amount of the acylamino acid and/or salt thereof used is 0.01 to 3% by weight, preferably 0.01 to 1% by weight, more preferably 0.1 to 1% by weight based on the amount of the finally obtained O/A emulsion. By using the acylamino acid and/or salt thereof in the above range, the particle size of the dispersed particles of the oily component can be reduced significantly (for example, the average particle size is reduced to about 7 or 2) as compared with the case where the particles are not used. When the amount is less than 0.01 wt%, the above-mentioned refining effect cannot be sufficiently obtained, and when it exceeds 3 wt%, irritation to the skin is increased, which is not preferable.

When the fatty acid ester is mixed with the acylamino acid and/or the salt thereof in a 3-or more-membered polyhydric alcohol, the reaction is preferably carried out while stirring at elevated temperature. The temperature at this time is not particularly limited as long as the above components are sufficiently dissolved in the polyol. Usually about 75 to 85 ℃. The stirring may be performed by a conventional stirrer.

Thus, a phase containing a 3-or more-membered polyol containing a specific fatty acid ester and an acylamino acid and/or a salt thereof is prepared. The remainder of this phase is preferably water. However, the additive component may be contained in a trace amount as long as the effect of the present invention is not impaired. Examples of such a component include ethanol. The concentration of these additional components is preferably less than about 5% by weight.

The oily component was added to the phase containing the 3-or more-membered polyol obtained above under stirring to prepare an O/a type emulsion. The type of the oily component is not particularly limited, but is preferably an oily component which is liquid at room temperature. Examples of the oily component include animal and vegetable fats and oils such as squalane, olive oil, macadamia nut oil, jojoba oil, coconut oil, and soybean oil, mineral oils such as hydrocarbons and liquid paraffin, ester oils such as cetyl isooctanoate, isopropyl myristate, and glyceryl trioctanoate, silicone oils such as dimethyl silicone, methylphenyl silicone, and cyclic silicone, higher alcohols such as 2-octyldodecanol, 2-decyltetradecanol, isostearyl alcohol, and oleyl alcohol, oil-soluble compounds such as vitamin a, vitamin D, vitamin E, vitamin K, coenzyme Q10, α -lipoic acid, rutin, lutein, and derivatives thereof, and oil-soluble pigments such as annatto pigment, pimento pigment, β -carotene, chlorophyll, monascus pigment, and curcumin. A mixture of a plurality of them may be used. For example, tocopherol derivatives (vitamin E derivatives) have a blood flow promoting effect, an antioxidant effect, and a skin softening effect, and are expected to have an effect of promoting hair growth.

The amount of the oily component used is 1 to 30% by weight, preferably 1 to 18% by weight, and more preferably 1 to 5% by weight based on the amount of the O/A emulsion. When the amount of the oily component used exceeds 30% by weight, an emulsion having a fine dispersed particle size cannot be obtained.

When the oily component is added, it is preferable to add the oily component by stirring a small amount at a time over a certain period of time. The temperature at which the oily component is added under stirring is not particularly limited, and is about 75 to 85 ℃. For the stirring, for example, a general stirrer having a rotor may be used, and for example, an emulsifying machine, a dispersive mixer, a paddle mixer, or the like may be used. In the present invention, when fine particles are formed, it is not necessary to use a microfluidizer or a Nanomizer as a high-pressure homogenizer for pulverizing dispersed particles under high pressure. For the stirring, a vacuum emulsion stirrer capable of stirring under vacuum is preferably used. By stirring under vacuum, the influence of bubbles can be removed, and an emulsion having stable quality can be formed.

In addition, when the O/a emulsion of the present invention is obtained, it is important to add an oily component to the polyol-containing phase. When a phase containing a polyol is added to an oily component, the oily component and the polyol phase separate from each other, and the emulsion desired in the present invention cannot be obtained.

In the O/A emulsion of the present invention (emulsion in which an oily component is dispersed in a phase containing a 3-membered or more polyhydric alcohol) obtained in this way, the average particle diameter of the dispersed particles of the oily component is 1 μm or less, preferably 800nm or less, more preferably 600nm or less, more preferably 300nm or less, and still more preferably 200nm or less. The lower limit of the average particle size in the present invention is not limited, but is estimated to be about 50 nm. The average particle diameter of the dispersed particles is measured using a laser diffraction particle size distribution measuring apparatus, a dynamic light scattering measuring apparatus, a particle diameter measuring apparatus using the coulter principle, or the like. In the present invention, the measurement is performed using a laser diffraction particle size distribution measuring apparatus.

In general, when an apparatus for micronizing particles by impact under pressure, such as a high-pressure homogenizer or a microfluidizer, is used, there are cases where the particle size distribution of dispersed particles becomes broad or a plurality of peaks are present, and there is an advantage that an O/a type emulsion obtained under relatively stable stirring in the present invention can obtain a particle size distribution having a single peak.

The O/a emulsion obtained according to the present invention can maintain dispersibility for a long period of time, and is also suitable for storage as a raw material for preparing, for example, a cosmetic or a composition for external application to the skin. The O/A emulsion obtained according to the present invention can be stored by cooling to room temperature or about 5 to 30 ℃.

(oil-in-water type emulsion)

An oil-in-water emulsion can be prepared by mixing the O/a emulsion obtained as described above with an aqueous medium. The aqueous medium is not particularly limited as long as water is used as a main component. For example, the cosmetic composition may further contain ingredients generally used in lotions and the like, for example, water-soluble polymers, moisturizers, ultraviolet absorbers, preservatives, pH adjusters, antioxidants, pigments, perfumes, aqueous pharmaceutical ingredients, and the like.

When the weight of the obtained oil-in-water emulsion is taken as 100, the mixing ratio of the O/a emulsion to the aqueous medium is preferably 90 to 99.5 in terms of the weight of the aqueous medium (the weight of water and the weight of other components when other components are contained) and 0.5 to 10 in terms of the weight of the O/a emulsion, because the stability and the feeling of use when used as an external preparation for skin are excellent. More preferably, the weight of the O/A emulsion is 1 to 5.

When the aqueous medium and the O/A type emulsion are mixed, the O/A type emulsion is added to the aqueous medium. The stirrer used in this case is not particularly limited, and any ordinary stirrer using a rotor may be used. The temperature at the time of mixing is not particularly limited, and may be determined depending on the stability of the oil component to be used, and the like. Usually, it is suitable to be about 30 to 40 ℃.

The oily component of the resulting oil-in-water emulsion has a fine dispersion particle size. The present inventors confirmed that the particle size distribution of the original O/A emulsion can be substantially maintained in the oil-in-water emulsion. Therefore, the average particle diameter of the dispersed particles of the oily component in the oil-in-water type emulsion is 1 μm or less, preferably 800nm or less, more preferably 600nm or less, more preferably 300nm or less, more preferably 200nm or less, as in the O/A type emulsion. Since the size of pores is generally about 200nm, when the particle size of the oil component is 200nm or less, the oil component (for example, including a hair growth promoting component) is likely to enter deep parts of the pores, and an improvement in hair growth effect is expected. The lower limit of the average particle size in the present invention is not limited, but is estimated to be about 50 nm. As described above, the average particle diameter of the O/a emulsion can be measured using a laser diffraction particle size distribution measuring apparatus, a dynamic light scattering measuring apparatus, a particle diameter measuring apparatus using the coulter principle, or the like. In the present invention, the measurement is performed using a laser diffraction particle size distribution measuring apparatus.

The oil-in-water emulsion obtained according to the present invention has a low viscosity, and preferably has a viscosity (25 ℃, 12rpm, spindle No. 1) of 1000 mPas or less, more preferably 300 mPas or less, as measured with a B-type viscometer. In the present invention, even with such a low viscosity, an oil-in-water emulsion having excellent dispersibility with time can be formed.

The oil-in-water emulsion of the present invention has a fine dispersion particle size and high skin permeability of oily components. In addition, the composition can be designed to have low viscosity, good feeling in use, and easy application to the skin. In particular, the viscosity is low and the permeability is high, so that it is very convenient to apply the hair-growing scalp. Further, the oil-in-water emulsion of the present invention can maintain dispersibility for a long period of time even at a low viscosity. Therefore, the oil-in-water emulsion of the present invention is not limited to this, and can be said to be applied to products such as cosmetics and skin external compositions. Examples of the composition for external application to the skin include cosmetics, health care products, and pharmaceuticals which are directly applied to the skin. Examples thereof include a cosmetic water, a cosmetic liquid, and a hair tonic. The cosmetics are products which are applied to the body by applying, spreading or other similar methods for the purpose of cleaning the body, beautifying, adding charm, changing the appearance or maintaining the health of the skin or hair, and which have a mild action on the human body, and include cosmetics such as skin care products (lotions, beauty liquids, face creams, shower gels, etc.), hair care products (shampoos, conditioners, hair tonics, etc.), color cosmetics, etc., perfumes containing perfume, etc.

Examples of the present invention will be described below, but the present invention is not limited thereto. The units of the numerical values relating to the amounts of the components blended in the tables below are all% by weight.

Examples

Reference example 1 Effect of the type of polyol on emulsification

The "polyol phase" components in each formulation of table 1 below were mixed using a dispersive mixer at an elevated temperature of 80 ℃. As POE sorbitan monooleate in Table 1, RHEODOL TW-O120V (addition mole number of ethylene oxide: 20) manufactured by Kao corporation was used, and as glycerin, cosmetic concentrated glycerin (glycerin content: 98.5% or more) was used. An oil component (glycerol tris (ethylhexanoate)) was slowly added thereto over a period of 5 minutes while stirring with a dispersion mixer (k. robomics (registered trademark) manufactured by PRIMIX corporation, rotation speed 3500rpm) at a temperature of 80 ℃. After the addition of the oily component was completed, stirring was continued at 80 ℃ for 30 minutes to prepare an O/A type emulsion. 10 parts by weight of an O/A type emulsion cooled to room temperature was mixed with an aqueous medium composed of 0.01 parts by weight of citric acid, 0.09 parts by weight of sodium citrate, 5 parts by weight of butylene glycol, 3 parts by weight of glycerin, 0.1 parts by weight of methyl paraben, and 81.8 parts by weight of purified water, to prepare an oil-in-water type emulsion. The average particle diameter of the oil-in-water emulsion thus obtained was measured using a laser diffraction particle size distribution analyzer (SALD-2200, Shimadzu Science). In addition, the measurement is carried out by diluting with water as appropriate according to a conventional method. The results are shown in Table 1. When only 2-membered 1, 3-butanediol is used as the polyol (formula A, B), separation occurs immediately after cooling after preparation from the O/A emulsion, and an oil-in-water emulsion cannot be prepared. The same applies to prescription F.

TABLE 1

Reference example 2 influence of kind of fatty acid ester on emulsification

The components of the "polyol phase" in each formulation of table 2 below were mixed using a dispersive mixer at an elevated temperature of 80 ℃. POE sorbitan monooleate in Table 2 was prepared using RHEODOL TW-O120V (addition mole number of ethylene oxide: 20) manufactured by Kao corporation; sorbitan sesquioleate is RHEODOL A-O15V, manufactured by Huawang corporation; as decaglycerol monomyristate, NIKKOL Decaglyn 1-M manufactured by sunlight Chemicals was used; POE hydrogenated castor oil NIKKOL HCO-40(POE40) manufactured by sunlight Chemicals was used; the glycerol is concentrated glycerol (glycerol content of 98.5% or more) for cosmetic. An oil component (isopropyl myristate; nikkolip-100, manufactured by solar Chemicals) was gradually added thereto over a period of 5 minutes while stirring with a dispersion mixer (k. romovics (registered trademark), manufactured by PRIMIX corporation, 3000rpm) at a temperature of 80 ℃ to prepare an O/a type emulsion. Thereafter, the mixture was cooled to room temperature, and the average particle diameter was measured using a laser diffraction particle size distribution analyzer (SALD-2200, Shimadzu Science). In addition, the measurement is carried out by diluting with water as appropriate according to a conventional method. The results are shown in Table 2. When POE hydrogenated castor oil was used as the fatty acid ester (formula J), the dispersion was poor and an emulsion having a desired particle size could not be obtained.

TABLE 2

(example 1)

The "polyol phase" components in each formulation of table 3 below were mixed using a dispersive mixer at an elevated temperature of 80 ℃. The myristyl monomyristate shown in Table 3 was NIKKOL Decaglyn 1-M manufactured by sunlight Chemicals; sorbitan sesquioleate is RHEODOL A-O15V, manufactured by Huawang corporation; POE sorbitan monooleate was prepared using RHEODOL TW-O120V (ethylene oxide addition molar number 20) manufactured by Kao corporation; sodium N-stearoyl-L-glutamate AMISOFT (registered trademark) HS-11P, manufactured by Aomoto corporation; the glycerol is concentrated glycerol (glycerol content of 98.5% or more) for cosmetic. An O/A type emulsion was prepared by gradually adding an oil component (mixed tocopherol; tocopherol 100 from Nissin OilliO Group Co., Ltd.) to a dispersion mixer (K. ROBOMICS (registered trademark) from PRIMIX Co., Ltd., rotation speed 8000rpm) at a temperature of 80 ℃ over a period of 5 minutes. And then cooled to room temperature. The average particle diameter was measured using a laser diffraction particle size distribution analyzer (SALD-2200, Shimadzu Science Co.). In addition, the measurement is carried out by diluting with water as appropriate according to a conventional method. The results are shown in Table 3. By adding the acylamino acid salt to the polyol phase, the average particle size of the oily component can be significantly reduced.

TABLE 3

(example 2)

The components of the "polyol phase" in each formulation of table 4 below were mixed using a dispersive mixer at an elevated temperature of 80 ℃. The myristyl monomyristate shown in Table 4 was NIKKOL Decaglyn 1-M manufactured by sunlight Chemicals; as decaglycerol monooleate, NIKKOL Decaglyn 1-OV manufactured by sunlight Chemicals was used; sodium N-stearoyl-L-glutamate AMISOFT (registered trademark) HS-11P, manufactured by Aomoto corporation; the glycerol is concentrated glycerol (glycerol content of 98.5% or more) for cosmetic. An oil component was gradually added thereto over a period of 5 minutes while stirring with a dispersion mixer (k. robomics (registered trademark) manufactured by PRIMIX corporation, 8000rpm) at a temperature of 80 ℃ to prepare an O/a type emulsion. Thereafter, the mixture was cooled to room temperature, and the average particle diameter was measured using a laser diffraction particle size distribution analyzer (SALD-2200, Shimadzu Science). For the measurement, the reaction mixture was diluted with water as appropriate according to a conventional method. As shown in Table 4, an O/A type emulsion having a fine particle size can be produced according to the present invention.

TABLE 4

(example 3)

The components of the "polyol phase" in each formulation of table 5 below were mixed using a dispersive mixer at an elevated temperature of 80 ℃. The myristyl monomyristate shown in Table 5 was NIKKOL Decaglyn 1-M manufactured by sunlight Chemicals; sodium N-stearoyl-L-glutamate AMISOFT (registered trademark) HS-11P, manufactured by Aomoto corporation; the glycerol is concentrated glycerol (glycerol content of 98.5% or more) for cosmetic. An O/a emulsion was prepared by gradually adding an oily component to a dispersion mixer (k. rolling (registered trademark) manufactured by PRIMIX corporation) at a temperature of 75 to 85 ℃ for 5 minutes while stirring the mixture with the mixer at 8000 rpm. Thereafter, the mixture was cooled to room temperature, and the average particle diameter was measured using a laser diffraction particle size distribution analyzer (SALD-2200, Shimadzu Science). In addition, the measurement is carried out by diluting with water as appropriate according to a conventional method. The resulting emulsion was stored at 40 ℃ and 75% RH for 6 months, and the average particle size was measured every 1 month during storage. The change in average particle diameter with time is shown in FIG. 1. The "6 months of storage at 40 ℃ and 75% RH" condition corresponds to 3 years of storage at room temperature. As shown in fig. 1, the O/a emulsion of the invention product 13 showed high dispersion stability over time without significant change in the dispersion particle size even when stored for a long period of time.

TABLE 5

(example 4)

As for the skin permeability of the product 13 of the present invention of example 3, a permeability test using a cultured skin model was performed as follows. 2ml of Phosphate Buffered Saline (PBS) was added to a 12-well plate, and a 3-dimensional cultured epidermis Model EpiSkin (registered trademark) Large Model was set. The product 12 of the invention was applied to the stratum corneum side of the skin model and incubation was started at 37 ℃. Skin models were collected 24 hours after application. The resulting skin model was added to a microcentrifuge tube containing 1ml of ethanol and pulverized using Tissue Lyser. 0.1ml of the supernatant was collected as a sample for measuring tocopherol acetate, and the amount of tocopherol acetate permeated into the skin was determined by High Performance Liquid Chromatography (HPLC). The results are shown in FIG. 2. As shown in fig. 2, it was confirmed that the product 13 of the present invention contained tocopheryl acetate with transdermal permeability.

(example 5)

Oil-in-water emulsions were prepared using the products 1 and 2 of the present invention of example 1. Specifically, the O/A type emulsions of the present invention products 1 and 2 were mixed with the aqueous medium phase at a temperature of 35 ℃ using a dispersive mixer according to the recipe of Table 6 below. The pH and absorbance (630nm) of the resulting oil-in-water emulsions (invention 14 and 15) were measured. Next, each of the oil-in-water emulsions (the present invention 14 and 15) was stored at 5 ℃ or 40 ℃ for 3 months, and changes in pH and absorbance during storage were measured. Further, it is considered that the absorbance of the emulsion generally relates to the size of the dispersion particle size of the emulsion, and the dispersion particle size becomes smaller as the absorbance becomes smaller. The results are shown in FIG. 3. As shown in fig. 3, all of the oil-in-water emulsions had long-term dispersion stability, and in particular, product 14 of the present invention using a polyglycerol fatty acid ester as a fatty acid ester had superior stability over time to product 15 of the present invention using a sorbitan fatty acid ester.

TABLE 6

(example 6)

An oil-in-water emulsion (hair growth agent) was prepared using the product 1 of the present invention of example 1. Specifically, the O/A type emulsion of invention product 1 was mixed with an aqueous medium phase at a temperature of 30 ℃ using a paddle mixer according to the recipe shown in Table 7 below. The viscosity of the obtained hair tonic was measured by a B-type VISCOMETER (VISCOMETER (MODEL: BM) manufactured by Toyobo Co., Ltd., 25 ℃, 12rpm, spindle No. 1) and found to be 130 mPas. The obtained hair tonic has no stickiness and good feeling in use.

TABLE 7

(example 7)

An oil-in-water emulsion (cosmetic water) was prepared using the inventive product 1 of example 1. Specifically, the O/A type emulsion of invention product 1 was mixed with an aqueous medium phase at a temperature of 30 ℃ using a paddle mixer according to the recipe shown in Table 8 below.

TABLE 8

Claims

1. An emulsion, comprising: 80 to 97% by weight of glycerin,

0.01 to 3 wt% of acylamino acid and/or salt thereof,

And 1 to 18% by weight of an oily component,

the oily component is dispersed in a phase comprising the glycerol.

2. The emulsion according to claim 1, wherein the fatty acid ester is a polyglycerin fatty acid ester.

3. The emulsion according to claim 1 or 2, wherein the acylamino acid and/or salt thereof is 0.01 to 1% by weight.

4. The emulsion according to claim 1 or 2, wherein the average particle size of the dispersed oily component is 1 μm or less.

5. An oil-in-water emulsion obtained by dispersing the emulsion according to any one of claims 1 to 4 in an aqueous medium.

6. The oil-in-water emulsion according to claim 5, comprising 90 to 99.5 wt.% of the aqueous medium.

7. The oil-in-water emulsion according to claim 5 or 6, characterized in that the viscosity measured by a B-type viscometer at 25 ℃, spindle No. 1, 12rpm is 1000 mPas or less.

8. The oil-in-water emulsion according to claim 5 or 6, wherein the average particle size of the dispersed oily component is 1 μm or less.

9. A cosmetic comprising the oil-in-water emulsion according to any one of claims 5 to 8.

10. A composition for external application to the skin, comprising the oil-in-water emulsion according to any one of claims 5 to 8.

11. A method for producing an emulsion, comprising the steps of: mixing a fatty acid ester selected from the group consisting of polyglycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters and mixtures thereof with an acylamino acid and/or a salt thereof in a liquid containing glycerin,

then, adding the oily component to the liquid containing glycerin under stirring to form an emulsion in which the oily component is dispersed in the liquid containing glycerin,

the fatty acid ester is in an amount of 1 to 10 wt% based on the amount of the emulsion; the acylamino acid and/or salt thereof is in an amount of 0.01 to 3 wt% based on the amount of the emulsion; the glycerin is in an amount of 80 to 97 wt% based on the amount of the emulsion; the oily component is in an amount of 1 to 18 wt% based on the amount of the emulsion.

12. A method for producing an oil-in-water emulsion, comprising the steps of: mixing a fatty acid ester selected from the group consisting of polyglycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters and mixtures thereof with an acylamino acid and/or a salt thereof in a liquid containing glycerin,

then, the oily component is added to the glycerin-containing liquid under stirring to form an emulsion in which the oily component is dispersed in the glycerin-containing liquid,

the fatty acid ester is in an amount of 1 to 10 wt% based on the amount of an emulsion in which an oily component is dispersed in a liquid containing glycerin; the amount of the acylamino acid and/or salt thereof is 0.01-3 wt% based on the amount of an emulsion in which an oily component is dispersed in a liquid containing glycerin; the glycerin is in an amount of 80 to 97 wt% based on the amount of an emulsion in which an oily component is dispersed in a liquid containing the glycerin; the oily component is in an amount of 1 to 18 wt% based on the amount of an emulsion in which the oily component is dispersed in a liquid containing glycerin.