JPH08245370A - O/w-type emulsion composition - Google Patents

Abstract

PURPOSE: To obtain an O/W-type emulsion composition having little stimulation against the skin owing to weak acidity and further excellent in storage stability without using a common surfactant. CONSTITUTION: This composition is obtained by compounding (A) a higher fatty acid, (B) a higher alcohol and (C) at least one kind selected from monoalkyl glycerin ethers and monoalkenyl glycerin ethers followed by adjusting the mixture to pH5.0-7.0. Preferably, the higher fatty acid of the component A is a fatty acid having a carbon number of 12-22, and the higher alcohol of the component B is an alcohol having an aliphatic hydrocarbon chain of 12-22 in a carbon number. Further, the ratios of (A)/(B) and [(A)+(B)]/(C) are preferably 0.1-1.0 and 1-10, respectively. The objective emulsion composition obtained by this process is fine and homogeneous, and has extremely little stimulation against the skin and excellent storage stability.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is an oil-in-water emulsion which does not use a general surfactant, is weakly acidic, is safe for the skin, has a good feeling of use, and has high storage stability. It relates to a composition. More specifically, (A) higher fatty acid, (B) higher alcohol and (C) one or more selected from monoalkyl glyceryl ether and monoalkenyl glyceryl ether are blended in a specific weight ratio, The present invention provides an oil-in-water emulsion composition which does not contain a general surfactant. The oil-in-water emulsion composition according to the present invention is particularly useful in the fields of cosmetics and pharmaceuticals.

[0002]

2. Description of the Related Art Conventionally, emulsions and creams for cosmetics,
Emulsified compositions are often used as cream bases or emulsions for pharmaceuticals. In particular, the oil-in-water emulsion composition,
The moist and non-greasy feeling of use is preferred, and it is often used as a hydrophilic base. Such an oil-in-water emulsion composition is usually stably prepared with a fatty acid soap and various surfactants. Further, in recent years, in order to obtain an emulsified composition that is mild to the skin, there is a tendency that a weakly acidic one having a pH close to the skin surface is preferred.

However, when a fatty acid soap is used, a weakly acidic emulsion composition cannot be obtained, and on the other hand, the irritation of the skin to the skin and the irritation of the eye mucosa pose a problem. Therefore, attempts have been made to reduce the blending amount of them as much as possible, and surfactants having different HLB values are combined little by little, an emulsification aid such as a higher alcohol is blended, and it is not a general surfactant. A method of supplementarily adding a substance having an amphipathic property has been studied. In JP-A-5-262619, two higher alcohols having 18 or more carbon atoms are combined and blended, and in JP-A-53-113787, JP-A-55-59106, JP-A-56-154408 and JP-A-4-15289. Is α-monoalkyl glyceryl ether and other α, β
An amphipathic substance such as a diol compound having a hydroxyl group at the position, a long-chain acyl acidic amino acid or a salt thereof,
It is blended in combination with higher fatty acid salts and hydrophilic surfactants.

Higher alcohols form a lamellar liquid crystal or gel structure together with a surfactant in the continuous phase of an oil-in-water emulsion composition, and stabilize dispersed oil droplets. The presence of an activator is essential. Further, the monoalkyl glyceryl ether used in the above-mentioned invention is an amphipathic substance but has a strong lipophilicity, and this alone does not have sufficient surface activity. It was currently used as a drug. Further, even when a higher alcohol was used in combination, the oil droplets could not be sufficiently dispersed and stabilized. Only an attempt to prepare an emulsion composition by using a special branched glyceryl ether such as α-mono (methyl branched alkyl) glyceryl ether as the monoalkyl glyceryl ether has been made (JP-A-56-39033).

[0005]

Therefore, the present invention solves the problems in the conventional emulsified composition as described above,
It has excellent storage stability even if it does not contain commonly used surfactants such as nonionic surfactants, anionic, cationic and amphoteric surfactants, and it is mildly acidic and irritates the skin. It is intended to provide an oil-in-water type emulsion composition having low properties and having a good appearance and a feeling of use.

[0006]

As a result of various studies to solve the above problems, the present inventors have found that conventionally used monoalkyl (or alkenyl) glyceryl ethers and higher fatty acids and higher alcohols are used. It was found that a stable, weakly acidic oil-in-water emulsion composition can be obtained without using a general surfactant by combining and blending them in a weight ratio within a certain range, and completed the present invention. .

That is, in the present invention, one of (A) higher fatty acid, (B) higher alcohol, and (C) monoalkyl glyceryl ether and monoalkenyl glyceryl ether is used.
One kind or two or more kinds are used as essential components, and water and oil are added thereto to prepare an oil-in-water type emulsion composition.

Examples of higher fatty acids (A) include straight chain saturated fatty acids such as undecyl acid, lauric acid, tridecyl acid, myristic acid, pentadecyl acid, palmitic acid, heptadecyl acid, stearic acid, nonadecanoic acid, arachidic acid and behenic acid, Straight chain unsaturated fatty acids such as undecylenic acid, oleic acid, elaidic acid, cetrainic acid, erucic acid, linoleic acid and linolenic acid, branched chain fatty acids such as isomyristic acid, isopalmitic acid and isostearic acid, 12-hydroxy fatty acid, etc. And a mixture of higher fatty acids such as lanolin fatty acid, and the like, and those having 11 to 22 carbon atoms are particularly preferable.

Examples of the higher alcohol (B) include lauryl alcohol, tridecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, straight-chain aliphatic saturated alcohols, oleyl alcohol, linoleyl alcohol, Examples include linear unsaturated fatty alcohols such as linolenyl alcohol, branched chain fatty alcohols such as hexyldecanol, isostearyl alcohol, and octyldodecanol, and mixtures of higher aliphatic alcohols such as cetostearyl alcohol and lanolin alcohol. Especially, those having an aliphatic hydrocarbon chain having 12 to 22 carbon atoms are preferable.

Examples of the monoalkyl glyceryl ether (C) include monopalmityl glyceryl ether (chimyl alcohol) and monostearyl glyceryl ether (batyl alcohol). Monoalkenyl glyceryl ethers include monooleyl glyceryl ether (ceracyl). Alcohol) and the like.

The composition of each of the above components suitable for obtaining a stable emulsified composition is within the shaded region in FIG. The compounding ratios of (A), (B) and (C) are approximately 5.3 to 45.1% by weight and 24.7 to 8% by weight of the total amount of these, respectively.
0.7 wt% and 10.0-50.0 wt% are suitable. Further, the weight ratio of (A) / (B) is 0.1 to 1.0, and the weight ratio of the total amount of (A) and (B) to (C) [(A) + (B)]. /
It is particularly preferable that (C) is 1-10.

In the oil-in-water emulsion composition according to the present invention, in addition to the higher fatty acid (A) and the higher alcohol (B),
Hydrocarbon oils such as squalane, liquid paraffin, isopropyl myristate, octyldodecyl myristate, ester oils such as isopropyl palmitate, avocado oil,
Vegetable oil such as olive oil, soybean oil, castor oil, mink oil,
Animal oils such as turtle oil, beeswax, animal waxes such as lanolin, jojoba oil, carnauba wax, vegetable waxes such as candelilla wax, and other general oily raw materials used as a base for cosmetics and pharmaceuticals, It can be used without particular limitation.

Further, p of the oil-in-water emulsion composition according to the present invention is
Preparation of H is adjusted using a buffer such as citrate buffer, a basic substance such as potassium hydroxide, sodium hydroxide or arginine, or a salt of a weak acid such as sodium lactate or sodium pyrrolidonecarboxylate with a strong base. can do. To reduce skin irritation, pH should be 5.0
It is preferably ˜7.0.

Further, the oil-in-water emulsion composition according to the present invention includes a moisturizer such as polyhydric alcohol, sugar and amino acid, physiologically active ingredients such as vitamins, nucleic acids and animal and plant extracts, preservative and ultraviolet absorber. , Dyes and the like can be blended as necessary.

The emulsion composition according to the present invention has the above-mentioned composition.
The components (A), (B) and (C) and the other oily component are mixed and heated to homogenize, and the water-soluble component is dissolved and added to the heated aqueous phase with stirring, and a homomixer is used. It can be obtained by emulsifying with an emulsifying machine such as. The stability can be further improved by using a more powerful high pressure homogenizer or ultrasonic emulsifier.

[0016]

In the oil-in-water emulsion composition according to the present invention,
The oily component can be stably emulsified without using a general surfactant, and a good appearance and usability can be obtained. Further, it is weakly acidic, has no skin irritation or sensitization property derived from pH or a surfactant, and can be stably stored for a long period of time.

[0017]

EXAMPLES The features of the present invention will be described in detail with reference to Examples. First, the formulation of the emulsion composition according to Example 1 of the present invention is shown in Table 1 together with Comparative Examples. In Table 1,
Mix (1) to (4) and heat to 80 ° C to homogenize
(5) to (7) are mixed and added to a mixture heated to 70 ° C. with stirring, and then emulsified by stirring with a homomixer at 70 ° C. to prepare.

[Table 1]

Table 2 shows the results of observing the pH, emulsified state and stability of Example 1 and Comparative Examples 1 to 3 shown in Table 1. As is clear from Table 2, the emulsified composition of Example 1 has uniform and fine emulsion particles having a particle size of 1 to 10 μm, a pH of 5.9 weak acidity, and 40 ° C. for 1 month. It was stable when stored. On the other hand, in Comparative Example 1 containing no stearic acid corresponding to the constituent component (A) of the present invention and Comparative Example 2 containing no monostearyl glyceryl ether corresponding to the constituent component (C) of the present invention, emulsification The composition could not be obtained. Further, in Comparative Example 3 in which the weight ratio (A) / (B) of the constituent component (A) and the constituent component (B) of the present invention is 3.0, the emulsion composition is obtained, but the particles of the emulsion are obtained. Diameter is 10μ
It was large when m or more, and was non-uniform. The emulsion stability was poor, and creaming and separation of the oil phase were observed the day after preparation.

[Table 2]

Next, the formulations of the cosmetic creams according to Examples 2 and 3 of the present invention are shown in Tables 3 and 4 together with Comparative Examples. In Example 2 and Comparative Example 4, (5) to (7) in Table 3 are
Dissolve in (9) and heat to 70 ° C, mix and dissolve it in advance and heat to 80 ° C (1) to (4) gradually add the oil phase components, then homogenize with a homomixer. Prepare by emulsifying, cooling and adding (8) at 40 ° C. In addition, in Example 3 and Comparative Example 5, (7) and (8) in Table 4 were dissolved in (10) and heated to 70 ° C.
It is prepared by adding the oil phase components (1) to (6) heated to 0 ° C., uniformly emulsifying with a homomixer, cooling and adding (9) at 40 ° C.

[Table 3]

[Table 4]

The skin irritation of Examples 2 and 3 and Comparative Examples 4 and 5 was examined. For skin irritation, a closed patch test was conducted for 48 hours using 30 panelists for each sample, and the results were evaluated according to the criteria shown in Table 5, and the average value of the skin irritation index of 30 people is shown in Table 6. It is shown together with the pH value of each sample.

[Table 5]

[0021]

[Table 6] As is clear from Table 6, the cosmetic creams of Examples 2 and 3 of the present invention have pHs of 5.8 and 6.
0 was weakly acidic and the skin irritation index was a very low value of 0.02 and 0.04, respectively. On the other hand, Comparative Example 4, which was emulsified by using a fatty acid soap and a nonionic surfactant in combination, was slightly alkaline with 8.3, and had a skin irritation index of 1.33, which was slightly irritating. For Comparative Example 5 emulsified with a nonionic surfactant,
Although the pH was weakly acidic at 5.5, it showed a considerably high skin irritation index of 2.59, and some skin irritation was recognized.

Next, the formulation of the emulsified composition according to the example of the present invention will be shown.

[Example 4] Weakly acidic cosmetic emulsion (1) Palmitic acid 0.4 (wt%) (2) Cetyl alcohol 1.5 (3) Lanolin alcohol 2.0 (4) Vaseline 3.0 (5) Avocado oil 10.0 (6) Monopalmityl glyceryl ether 2.0 (7) Glycerin 3.0 (8) Sodium lactate 2.0 (9) Methyl paraoxybenzoate 0.1 (10) Perfume 0.1 (11 ) Purified water 75.9 [Production method] (7) to (9) are dissolved in (11) and heated to 70 ° C,
This was mixed and dissolved in advance and heated to 80 ° C (1)
After adding (6), emulsify with a homomixer, cool and add (10) at 40 ° C.

Example 5 Weakly Acidic Cosmetic Milk Liquid (1) Myristic Acid 0.7 (wt%) (2) 12-Hydroxystearic Acid 0.5 (3) Oleyl Alcohol 5.0 (4) Behenyl Alcohol 1.2 (5) Jojoba oil 15.0 (6) Monooleyl glyceryl ether 0.8 (7) Tocopherol acetate 0.5 (8) 1,3-Butanediol 5.0 (9) Arginine 2.0 (10) Paraoxybenzoic acid Methyl acid 0.1 (11) Perfume 0.1 (12) Purified water 69.1 [Production Method] (8) to (10) are dissolved in (12) and heated to 70 ° C., and mixed and dissolved in advance. And heated to 80 ° C
After adding (1) to (7), emulsify with a homomixer, cool and add (11) at 40 ° C.

Example 6 Weakly acidic emulsion type ointment base (1) Linoleic acid 0.5 (wt%) (2) Cetostearyl alcohol 5.0 (3) Squalane 10.0 (4) Vaseline 6.0 (5) Monostearyl glyceryl ether 1.0 (6) Tocopherol acetate 0.2 (7) Propylene glycol 10.0 (8) Sodium citrate 3.0 (9) Methyl paraoxybenzoate 0.1 (10) Purified water 64.2 [Production method] (7) to (9) are dissolved in (10) and heated to 70 ° C,
This was mixed and dissolved in advance and heated to 80 ° C (1)
After adding (6), emulsify with a homomixer and cool.

[Example 7] Weakly acidic emulsion type ointment base (1) Lanolin fatty acid 1.0 (wt%) (2) Cetyl alcohol 2.0 (3) Isostearyl alcohol 3.0 (4) Isopropyl myristate 5.0 (5) Liquid paraffin 5.0 (6) Monopalmityl glyceryl ether 0.8 (7) Monooleyl glyceryl ether 0.2 (8) Tocopherol acetate 0.2 (9) Propylene glycol 5.0 (10 ) Sodium lactate 4.0 (11) Methyl paraoxybenzoate 0.1 (12) Purified water 73.7 [Production Method] (9) to (11) are dissolved in (12) and heated to 70 ° C. Mix and dissolve in advance and heat to 80 ° C
After adding (1) to (8), emulsify with a homomixer and cool.

The weakly acidic cosmetic emulsions of Examples 4 and 5 and the weakly acidic emulsion type ointment bases of Examples 6 and 7 are all uniform and fine emulsion particles having a particle size of 1 to 10 μm. And was stable at 5 ° C. and 40 ° C. for 1 month or longer.

[0028]

As described above in detail, according to the present invention, a stable and good oil-in-water emulsion composition can be obtained without using a general surfactant. Furthermore, the oil-in-water emulsion composition according to the present invention is weakly acidic, has extremely low irritation to the skin, and is useful as an emulsion composition for cosmetics such as emulsions and creams, or for pharmaceuticals such as emulsions and ointment bases. .

[Brief description of drawings]

FIG. 1 is a diagram showing an appropriate composition of constituent components (A), (B) and (C) in the present invention.

Claims (4)

[Claims] 1. (A) higher fatty acid, (B) higher alcohol, and
(C) An oil-in-water emulsion composition containing one or more selected from monoalkyl glyceryl ethers and monoalkenyl glyceryl ethers, and having a pH of 5.0 to 7.0. 2. The higher fatty acid (A) has 11 to 22 carbon atoms.
The oil-in-water emulsion composition according to claim 1, which is a fatty acid of 3. The higher alcohol (B) has 12 to 12 carbon atoms.
The oil-in-water emulsion composition according to claim 1 or 2, wherein the oil-in-water emulsion composition has 22 aliphatic hydrocarbon chains. 4. A higher fatty acid: higher alcohol weight ratio.
(A) / (B) is 0.1 to 1.0, and the weight of the total amount of higher fatty acid and higher alcohol and one or more selected from monoalkyl glyceryl ether and monoalkenyl glyceryl ether. Ratio [(A) + (B)] / (C) is 1
The oil-in-water emulsion composition according to claim 1, which is 10 to 10.