JPH11276881A - Emulsion and cosmetics made of emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the arranging of a large amount of a polyhydric alcohol without impairing a feeling of use and make the ambience compatible with the emulsifiability by dispersing the particles of a polyhydric alcohol or a highly concentrated aqueous polyhydric alcohol solution, the particles being covered with oil on the surface, in the water of a continuous phase. SOLUTION: This emulsion is manufactured by preparing an emulsion of a polyhydric alcohol or an aqueous polyhydric alcohol solution and oil, in the oil of a continuous phase, based on the polyhydric alcohol or the highly concentrated aqueous polyhydric alcohol solution, the oil and a first emulsifier, and then emulsifying the emulsion and an aqueous composition in the presence of a second emulsifier. The first emulsifier is an ester of polyglycerin and a fatty acid with 2 or more polymerization degree and is preferably a hepta 12-hydroxydecaglycerin stearate. The second emulsifier is not particularly defined but is preferably an emulsion composition of a decaglycerylpentastearate, a stearoyl lactic acid and a behenylalcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emulsion having a specific structure, a method for producing the same, and a cosmetic containing the emulsion.

[0002]

2. Description of the Related Art Conventionally, W / O type and O / W type emulsions have been used for cosmetics and pharmaceutical preparations.
By using these water-oil emulsions,
Since both the oil component and the aqueous component can be supplied at the same time, and the combination can be easily changed depending on the application, the utility value thereof is high. For example, cosmetics such as various creams such as vanishing cream, cold cream, cleansing cream and emollient cream, various lotions such as emollient lotion and hair lotion, and pharmaceuticals such as ointments, emulsions and liquid dosage forms.
/ O and O / W emulsions are used.

[0003] Polyhydric alcohols such as glycerin have been blended in order to enhance the moisturizing properties of cosmetics utilizing O / W type emulsions, but on the other hand, the cosmetics become sticky and the feeling of use is impaired. There was a disappointment. on the other hand,
A W / O emulsion has been awarded as a cosmetic having excellent emollient properties, but this type of emulsion has a poor feeling of use because the external phase is an oil phase.

[0004] In addition, emulsion-type cosmetics often contain vitamins and other chemicals in addition to components that impart emolliency.

[0005]

However, in the conventional emulsion type cosmetics, a large amount of polyhydric alcohol is required to enhance the moisturizing property of both W / O type and O / W type emulsions. However, it is difficult to mix them without deteriorating the feeling of use. Therefore, it has been difficult to prepare an emulsion having both good moisture retention and good usability and good emollient properties.

[0006] Further, since some vitamins become unstable upon contact with water, when blending them into emulsion type cosmetics, a method of encapsulating them in a hard shell and blending them has been adopted. However, in this method, the feeling of use is significantly reduced. In addition, a method has been proposed in which vitamins are separately packaged and added when cosmetics are used, but this is disadvantageous in terms of cost and workability.

[0007] Under these circumstances, an object of the present invention is to provide an emulsion in which a large amount of a polyhydric alcohol can be blended without impairing the feeling of use, and which has both emollient properties and stability of the emulsion. Still another object of the present invention is to provide a method of stably blending an emulsion-type cosmetic with a component which becomes unstable when it comes into contact with water.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies from the above viewpoints, and as a result, have found that an emulsion having a specific structure can achieve the above object, and have completed the present invention.

That is, the present invention provides an emulsion characterized in that particles of a polyhydric alcohol whose surface is covered with oil or a high-concentration polyhydric alcohol aqueous solution are dispersed in water as a continuous phase, and an emulsion comprising the emulsion. The present invention provides a cosmetic comprising an active ingredient in at least one phase of the emulsion and a method for producing the emulsion.

In the emulsion of the present invention, the surface of polyhydric alcohol particles dispersed in water as a continuous phase is covered with oil, so that the polyhydric alcohol does not come into contact with water. Therefore, stability can be ensured by blending in the polyhydric alcohol a component that becomes unstable when it comes into contact with water, such as vitamins. Further, since the surface of the polyhydric alcohol is covered with the oil, the effect of replenishing the aqueous component and the oil component, which are the characteristics of the conventional W / O and O / W emulsions, is not impaired.

The "polyhydric alcohol" used in the present invention refers to an alcohol having two or more hydroxyl groups in the same molecule. Depending on the number of hydroxyl groups, there are dihydric alcohols and trihydric alcohols, and pentahydric alcohols and the like. Hexahydric alcohol,
Also included are sugar alcohols formed by the reduction of monosaccharides. In the present invention, it is necessary to select a polyhydric alcohol that is soluble in water and incompatible with oil. Polyhydric alcohols include, for example, propylene glycol, 1,3
-Butylene glycol, ethylene glycol, glycerin, glucose, maltose, maltitol, sucrose, fructose, xylitol, inositol, pentaerythritol, trehalose, etc .; Aqueous solution. Here, the high-concentration aqueous solution can vary relatively depending on the substance, but usually contains 30% by weight or more, preferably 50% by weight or more of a polyhydric alcohol. One or more of these can be used depending on the use of the emulsion. The emulsion of the present invention preferably contains 5 to 60% by weight, particularly 10 to 50% by weight of a polyhydric alcohol.

The oil used in the present invention is an ester of a fatty acid, particularly a medium chain fatty acid and glycerin, and any of a natural product and a synthetic product can be used, but a natural product is preferably used. Examples of oils and fats include hydrocarbons such as liquid paraffin, esters of fatty acids such as isopropyl myristate and monoalcohols, esters of fatty acids such as fatty acid triglycerides derived from natural products and polyhydric alcohols, and silicones. In addition, the oil referred to in the present invention includes, besides the above, those which are substantially insoluble in both the continuous phase water and the polyhydric alcohol contained therein.

The emulsion of the present invention having such a structure is a polyhydric alcohol or a high-concentration polyhydric alcohol aqueous solution and a high-concentration polyhydric alcohol or high-concentration polyhydric alcohol aqueous solution / oil emulsion in which the oil and the first emulsifier contain oil as a continuous phase. (I) is prepared, and then the emulsion (I) is prepared.
And the aqueous composition by emulsifying in the presence of a second emulsifier. Here, as the first emulsifier, an ester of a polyglycerol having a polymerization degree of 2 or more and a fatty acid, and an ester having a degree of esterification of 40 to 70% with respect to the hydroxyl group of the polyglycerin is particularly preferable. Specifically, hepta 12-hydroxystearate decaglyceryl is preferred. Although there is no limitation on the second emulsifier, as those that do not affect the human body and the environment, acrylic acid-alkyl methacrylate copolymer, sucrose fatty acid ester, decaglyceryl pentastearate, sodium stearoyl lactate and behenyl alcohol Emulsifier composition or the like is more preferable, and more preferable is an emulsifier composition comprising decaglyceryl pentastearate, sodium stearoyl lactate and behenyl alcohol. This emulsifier composition comprises decaglyceryl pentastearate 20
-60% by weight, sodium stearoyl lactate 1-20% by weight, and behenyl alcohol 30-70% by weight. Polyglycerin fatty acid ester is a very safe surfactant, and by appropriately selecting a polyhydric alcohol, it is possible to provide a highly functional multi-phase emulsion in the cosmetic and pharmaceutical fields. In addition,
Examples of the “aqueous composition” include water, an aqueous solution, an O / W emulsion, and a W / O emulsion.

The method for producing the emulsion of the present invention will be described more specifically as follows. (1) First, polyhydric alcohol / oil emulsion (I)
A polyhydric alcohol or a high-concentration polyhydric alcohol aqueous solution or a polyhydric alcohol or a high-concentration polyhydric alcohol aqueous solution containing a salt or an active ingredient, in the presence of the first emulsifier, is used as an oil that can be used as a cosmetic or pharmaceutical. , Is prepared by adding The first emulsifier is preferably capable of forming a liquid crystal. (2) The above-mentioned emulsion (I) is added to an aqueous composition such as an O / W emulsion comprising water or an oil and water in the presence of a second emulsifier or an aqueous solution thereof, and the polyhydric alcohol of the present invention or A high concentration polyhydric alcohol aqueous solution / oil / water type multiple emulsion is prepared. If necessary, a thickener or the like can be added to this polyhydric alcohol or high-concentration polyhydric alcohol aqueous solution / oil / water type multi-phase emulsion. In the above (1) and (2), the mixing ratio of each component,
Various conditions such as mixing conditions (temperature, stirring speed, etc.) are not limited.

The emulsion (I) is an emulsion characterized in that particles of a polyhydric alcohol or a high-concentration polyhydric alcohol aqueous solution are dispersed in an oil which is a continuous phase. The precursor emulsion itself can be used for cosmetics and the like, but is useful as a precursor of the multi-phase emulsion of the present invention.

As described above, in the present invention, a polyhydric alcohol or a high-concentration polyhydric alcohol aqueous solution / oil / water type polyphasic emulsion can be obtained, and the polyphasic conversion rate is preferably 60% or more. It is more preferably at least 70%. The higher the polyphasic conversion rate, the more the stability and feeling of use of the emulsion improve. This polyphase conversion rate is calculated by the following method.

<Method of Measuring Polyphasic Conversion Ratio> A polyhydric alcohol aqueous solution in which sodium chloride is dissolved together with as little water as possible is prepared in advance, and a polyphasic emulsion is prepared using this polyhydric alcohol aqueous solution. The electrical conductivity of this multi-phase emulsion was measured and separately prepared from the electrical conductivity of the multi-phase emulsion containing a known amount of salt in the outermost aqueous phase of the multi-phase emulsion having the same composition as this multi-phase emulsion. Quantify the salt amount of the outermost phase from the calibration curve. From this salt amount, the amount of the polyhydric alcohol aqueous solution which is not involved in the formation of the polyphasic emulsion is obtained, and the polyphasic conversion rate for forming the target polyphasic emulsion is calculated. That is,

[0018]

(Equation 1)

## EQU1 ##

The emulsion of the present invention is particularly useful as a cosmetic. The cosmetics using the emulsion of the present invention are not limited, but include, for example, creams such as emollient creams, emulsions and the like, and vitamins and other drugs may be added to these to have a medicinal effect. No.

Such a cosmetic contains an active ingredient in at least one phase constituting an emulsion, and contains water,
Oils and polyhydric alcohols themselves may be the active ingredients.

[0022]

The polyphasic emulsion of the present invention contains a polyhydric alcohol or a high-concentration polyhydric alcohol aqueous solution, but can maintain long-term storage stability, so that an emulsion-type cosmetic excellent in emollient properties can be obtained. Can be.
Further, the polyhydric alcohol or high concentration polyhydric alcohol aqueous solution / oil / water type multi-phase emulsion of the present invention has a polyhydric alcohol or high concentration polyhydric solution in which the outermost phase is water and the innermost phase is cut off from the aqueous phase. Because it is a phase of an aqueous alcohol solution,
By blending components, such as vitamins, which become unstable when in contact with water, into the phase of a polyhydric alcohol or a high-concentration polyhydric alcohol aqueous solution, these components can be blended stably.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited to these examples.

Example 1 <Preparation of polyhydric alcohol / oil emulsion (I)> 5% by weight of decaglyceryl hepta-12-hydroxystearate (first emulsifier), 1% by weight of aluminum magnesium hydroxide stearate, 19% by weight of medium-chain triglyceride (oil and fat) and glycerin (polyhydric alcohol)
Emulsion (I) was prepared using 74% by weight and 1% by weight of sodium chloride. First, of the above components,
Hepta 12-hydroxystearate decaglyceryl,
While stirring the aluminum magnesium stearate and the medium-chain triglyceride, glycerin in which sodium chloride was uniformly dissolved was added, and then stirring was continued for a while to obtain an emulsion (I) (phase A).

<Preparation of Multi-Phase Emulsion> Of the components in Table 1, the components of phase B are mixed while heating to 85 ° C., and homogeneously dissolved or dispersed to obtain phase B. Further, while stirring the phase C, the phase B is added to obtain an O / W emulsion or an aqueous surfactant solution. The “polyglycerin stearate” of phase B in Table 1 is decaglyceryl pentastearate. Phase C "Carbopol 980" is an acrylic acid / alkyl methacrylate copolymer manufactured by BF Goodrich. In Table 1, POE stands for polyoxyethylene. The emulsion (I) obtained above was added to the O / W emulsion or the aqueous surfactant solution, and the mixture was stirred for a while, and then cooled while stirring to obtain a multi-phase emulsion.

<Evaluation of Multiphase Emulsion> With respect to the emulsions shown in Table 1, the emulsified state immediately after preparation and the emulsion stability were evaluated. In addition, the usability was evaluated. In addition, the multiphase conversion ratio (immediately after preparation / 25 ° C.) measured by the above method is also shown. The methods for evaluating the emulsion stability and the feeling upon use are as follows.
In addition, the structure of the emulsion shown in Table 1 was confirmed from the micrograph and the multi-phase conversion. As a result, it was confirmed that the compositions 1-1 to 1-4 were the multi-phase emulsions of the present invention. Composition 1-5 partially and temporarily forms a multiphasic emulsion but is unstable, and compositions 1-6 and 1-7
The emulsion structure could not be taken, and the polyphase conversion could not be calculated.

* Evaluation of emulsion stability 3 months at 5 ° C, 1 year at room temperature (25 ° C), 3 months at 45 ° C, 6 hours at -5 ° C, heating from -5 ° C to 50 ° C in 6 hours, 50 ° C at 50 ° C The emulsified state was observed under four conditions of storage for 3 months in a cycle of cooling from 6 hours to 50 ° C. to −5 ° C. for 6 hours. The evaluation criteria for the emulsion stability are as follows. A: No phase separation was observed. ：: phase separation is less than 5%. Δ: phase separation is 5% or more. ×: Separated or O / W or W / O emulsion. Alternatively, an emulsion cannot be formed.

* Feeling of use Twelve test subjects were allowed to use the composition after storage at 45 ° C. for 3 months, and the average was evaluated. The evaluation criteria are as follows. ：: Refreshing without stickiness. ：: Slightly sticky, but refreshing. Δ: Sticky feeling. X: The stickiness is remarkable.

[0029]

[Table 1]

Example 2 Emulsion (II) was prepared in the same manner as in Example 1, except that 19% by weight of dimethylpolysiloxane (300 st: 25 ° C.) was used in place of the medium-chain triglyceride used for preparing emulsion (I). Except for the above, a multi-phase emulsion was prepared in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. Table 2 shows the results. The structure of the emulsion was confirmed in the same manner as in Example 1. As a result, the composition 2-1 was obtained.
2-4 were confirmed to be the multiple emulsions of the present invention. Composition 2-5 partially and temporarily formed a multiphasic emulsion, but was unstable.
6, 2-7 cannot take an emulsion structure,
Polyphase conversion could not be calculated.

[0031]

[Table 2]

Claims (6)

[Claims] 1. An emulsion characterized in that particles of a polyhydric alcohol or a high-concentration polyhydric alcohol aqueous solution whose surface is covered with oil are dispersed in water as a continuous phase. 2. The emulsion according to claim 1, wherein the emulsion is obtained by an emulsifier containing an ester of a polyglycerin having a degree of polymerization of 2 or more and a fatty acid. 3. A cosmetic comprising the emulsion according to claim 1 or 2, wherein an active ingredient is contained in at least one phase of the emulsion. 4. An emulsion characterized in that particles of a polyhydric alcohol or a high-concentration polyhydric alcohol aqueous solution are dispersed in an oil that is a continuous phase. 5. A polyhydric alcohol or high-concentration polyhydric alcohol aqueous solution / oil emulsion (I) having an oil as a continuous phase is prepared from a polyhydric alcohol or high-concentration polyhydric alcohol aqueous solution and an oil and a first emulsifier, By emulsifying the emulsion (I) and the aqueous composition in the presence of a second emulsifier, an emulsion in which particles of a polyhydric alcohol whose surface is covered with oil is dispersed in water as a continuous phase. A method for producing an emulsion, which comprises producing the emulsion. 6. The first emulsifier is an ester of a polyglycerin and a fatty acid having a degree of polymerization of 2 or more, and an ester having a degree of esterification of 40 to 70% with respect to a hydroxyl group of the polyglycerin. The method for producing an emulsion according to claim 5, wherein the emulsifier is an emulsifier composition comprising decaglyceryl pentastearate, sodium stearoyl lactate, and behenyl alcohol.