JPS60166604A - Preparation of weakly acidic w/o/w-type emulsion cosmetic - Google Patents

Abstract

PURPOSE:To obtain the titled cosmetic having extremely excellent stability, by preparing a W/O-type emulsion by adding water to an oily phase mixed with an oleophilic surfactant, and emulsifying the emulsion with water using a hydrophilic surfactant and an N-(long-chain acyl)amino acid soap. CONSTITUTION:An oleophilic surfactant having an HLB value of <=9 (e.g. sorbitan fatty acid ester, sucrose fatty acid ester, etc.) is mixed in an oily phase such as vegetable oil, wax, etc. and then water is added to the mixture to obtain a W/O-type emulsion. The W/O-type emulsion is emulsified with water using a hydrophilic surfactant having an HLB value of >=10 (e.g. polyglycerol monofatty acid ester, polyoxyethylene alkyl ether, etc.) in combination with an N-(long- chain acyl)amino acid soap to obtain a weakly acidic W/O/W-type emulsion cosmetic. When a water-soluble polymer is added to the outer aqueous phase of said emulsion, it acts as a protective colloid of the emulsion and the stability is further improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a novel weakly acidic W10/W type emulsified cosmetic. The purpose is to establish a weakly acidic Who/- type emulsified cosmetic material method with excellent stability.
A 10/- type emulsion is also called a multiple emulsion or a composite emulsion, and its particles and structure are 1.A normal 07-type emulsion simply disperses an oil phase in an aqueous phase. On the other hand, it has a structure in which an aqueous phase is further dispersed in a dispersed oil phase. Hereinafter, the external aqueous phase in which the oil phase is dispersed is referred to as the external aqueous phase,
The internal aqueous phase further dispersed in this oil phase will be referred to as the internal aqueous phase.

Conventionally, regarding W10/W type emulsion, 4 yen
Due to its thin particle structure, applications in the fields of cosmetics, pharmaceuticals, food, etc. are being considered, and a 41F patent has also been applied for (Japanese Patent Publication No. 55-23087.4 ￥ Open/close 5
2-134029, JP 58-6530, JP 11/
+ 57-15829, JP 57-68123, JP 57-201526, JP 58-183611, JP 58-183612, U.S. Patent 2,399,263
British Patent No. t, 235, 667).

However, W10/
W-type emulsions generally have poor stability, and this point has hindered their practical use. By the way, the reasons why W10/W type emulsions are generally unstable are: (1) There is often a difference in osmotic pressure between the inner water phase and the outer water phase, and the oil containing the inner water phase Water movement occurs through the phase due to the osmotic pressure gradient, eventually breaking the emulsified droplets.

■ In the conventional technology, the particle size of the obtained emulsion was non-uniform and the system was likely to become unstable.

There are many things that can be considered.

Therefore, the present inventors solved the drawback of lack of stability and developed W10/W, a weakly acidic product that is extremely excellent as a cosmetic.
The present invention was achieved as a result of intensive research to obtain a type of emulsified cosmetic.

That is, in the method for producing a weakly acidic W10/W type emulsified cosmetic according to the present invention, first, a lipophilic surfactant (HL B 4
ti of 9 or less) is mixed into the oil phase,
Next, water is added to prepare a W10 type emulsion, and then the W10 type emulsion and an aqueous phase are emulsified by a combination of a hydrophilic surfactant and an N-long chain acylamino acid soap. The N-long chain acylamino acid soap not only makes the pH of the W10/ill emulsion slightly acidic, but also gives structure to the outer aqueous phase.
It is also useful for stabilizing 0/- type emulsions.

Lipophilic surfactant used in the present invention (HLB value of 9 or more)
Various types of fatty acid esters can be used, including sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene castor oil fatty acid esters, polyoxyethylene hydrogenated castor oil fatty acid esters, diglycerin fatty acid esters, pentaerythritol fatty acid esters, and sorbitan fatty acid esters. Sugar fatty acid esters can be used alone or in combination of two or more, and the amount used is 0.1 to IO weight % [1f capacity]. That is, if it is less than 0.1% by weight, water cannot be retained in the oil phase and a W10/W type emuldigon cannot be formed. Also, the use of 1O weight percent or more is problematic from the safety point of view.

Next, as the oil phase component, those that are normally used in the fields of cosmetics, medicine, food, etc. and are considered safe for the human body can be used. For example, vegetable oils such as olive oil and castor oil, waxes such as beeswax, lanolin φ candelilla wax, and wood wax, hydrocarbons such as liquid paraffin, squalane-based petrolatum φ paraffin wax, cetanol, stearyl alcohol, behenyl alcohol, etc. higher alcohols, monoglycerides such as glyceryl monostearate and glyceryl monooleate, higher fatty acids such as stearic acid, palmitic acid, myristic acid, α-monoglycerin ethers such as batyl alcohol and chimyl alcohol, other ester oils, and silicone oils. etc. can be mentioned.

The amount of water used to prepare the W10 type emulsion is 0.5 to I5 times the amount of the lipophilic surfactant used. The advantage of the -10/- type emulsion is lost.In addition, the -10 type emulsion orientation is too strong in the 15 times product and the -10 type emulsion has a negative effect on the stability of the W10/W type emulsion. .

Various kinds of wood-philic surfactants (those with an HLB value of IO or higher) can be used in the present invention, including polyglycerin 1,000 fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and polyoxyethylene sorbitan fatty acid ester. Ester, polyoxyethylene glycerin fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene phytosterol, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene castor oil, polyoxy Can be used in combination of one or more of ethylene hardened mustard oil, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, and sucrose fatty acid ester, and can be used in an amount of 0.1 to 5% by weight. It is. In other words, at 0.1 tonne % or less, W10J%
The Ij emulsion cannot be stably emulsified with the external aqueous phase. Moreover, if it is more than 5% by weight, the W10/W type emulsion becomes oriented toward the 01111 type emulsion, resulting in poor stability.

The N-long chain acylamino acid soap used in the present invention is N-
It is a reaction product obtained by reacting a long-chain acylamino acid with a base. The N-long chain acylamino acid used to synthesize this N-long chain acylamino acid soap has a fatty acid tl/j acid having 12 to 2 B carbon atoms. Particularly preferably, N-stearoylglutamine@-N-valmitoylglutamic acid-N-myristoylglutamic acid/N-stearoyl aspartic acid/
Examples include N-balmitoylaspartic acid and N-myristoylaspartic acid. Also, these N
-Long-chain acylamino acids can be used regardless of whether they are D, L, or DL. Moreover, these may be used in a single combination or in a plurality of combinations.

On the other hand, bases used to synthesize N-long chain acylamino acid soaps include triethanolamine, triisopanolamine, 2-amino-2-methyl-1-
Among these, basic amino acids include propatool, 2-amino-2-methyl-1,3-propanediol, sodium hydroxide, potassium hydroxide, arginine, lysine, histidine, ornithine, and oxylysine. Any of these bases can be used regardless of whether they are D, L, or DL, and these bases may be used alone or in combination. In addition, the amount of base used is 0.02 to 1 when basic amino acids are used per N-long chain acyl amino acid weight 1.
．． The ratio is preferably 0.0, more preferably 0.2 to 0.6, and when amines are used, the ratio is 0.01 to 1.0, more preferably 0.05 to 0.5. When using, the ratio is preferably 0.001 to 0.3, more preferably 0.01 to 0.1.

Now, the use of the N-long chain acylamino acid soap of the present invention is 0.01 to 5% by weight. No action or effect is produced.Moreover, if it exceeds 5% by weight, the osmotic pressure of the external aqueous phase becomes too high, resulting in a 0/W type emulsion, resulting in poor stability.

Furthermore, the external aqueous phase may contain ingredients that are commonly used as aqueous phase components of cosmetics. For example, wetting agents such as propylene glycol and glycerin, alkalis, acids,
Examples include salts, pigments, fragrances, preservatives, ultraviolet absorbers, beauty agents, water-soluble polymers, and amino acids.

To produce a weakly acidic -10/- type emulsified cosmetic according to the present invention, (1) A lipophilic surfactant is heated and mixed and dissolved in an oil phase. In this case, an oily gelling agent may be added to the oil phase. As an oil-based gelling agent, starch Il! -1 There is a mechanical bentonite containing costic acid ester and silicic anhydride. The effect is that in the W10 emulsion to be prepared next, the presence of the lipophilic surfactant allows the internal aqueous phase to be uniformly dispersed in the oil phase, and the network structure of the oil-based gelling agent allows it to exist stably. This contributes to the stabilization of the W10/W type emulsion.

(2) The heated internal aqueous phase component is added to the obtained product while stirring and emulsified to obtain a W/θ emulsion. In this case, an acid and/or a salt thereof may be added to the internal aqueous phase in advance. Examples of acids and their salts include citric acid and
Organic acids such as lactic acid, tartaric acid, malic acid, pyrrolidone carboxylic acid, and sodium salts, potassium salts,
There are triethanolamine salts, as well as zinc sulfate and
Magnesium sulfate, potassium aluminum sulfate, aluminum sulfate, zinc chloride, magnesilla chloride 11Φ11! Examples include metal 11X such as aluminum oxide. The effect is that the gel structure within the W10 emulsion to be formed becomes stronger, which in turn contributes to the stability of the W10/W emulsion. Furthermore, by appropriately combining this acid and its salts, W
The pH of the internal aqueous phase of the 10/- type emulsion can be freely selected. That is, it has the advantage that it can be made weakly acidic, which is the pH level of healthy bare skin.

1. The obtained 10-type emulsion is stirred and dispersed in an external aqueous phase in which a woodphilic surfactant and an N-long chain acylamino acid soap are heated and dissolved, or a hydrophilic surfactant and If an external aqueous phase component obtained by heating and dissolving an N-long chain acylamino acid soap is added to a 1l JW10 type emulsion and phase inversion emulsification is carried out, a weakly acidic W10/W type emulsified cosmetic can be obtained. In this way, the pH of the external aqueous phase can be freely selected by selecting an N-long chain acylamino acid soap, which has the advantage of making it slightly acidic, which is the pH of healthy bare skin.

Furthermore, the ionic strength of the N-long chain acylamino acid soap allows the osmotic pressure difference between the inner and outer aqueous phases to be controlled. That is, by reducing the difference in osmotic pressure between the internal and external aqueous phases, stability can be significantly improved.

In addition, when a water-soluble polymer is blended into the outer aqueous phase, the water-soluble polymer acts as a protective colloid for the emulsion, and W1
The stability of the 0/W emulsion is further increased. Water-soluble polymers are also effective as feel improvers.

Examples of water-soluble polymers include carboxyvinyl polymer, polyvinyl alcohol, polyvinylpyrrolidone, guar gum, methyl cellulose, hydroxyethyl cellulose, gum arabic, sodium polyacrylate, sodium alginate, karakeenan, and carboxymethyl cellulose.

Next, the present invention will be further explained by giving Examples.

These do not limit the present invention in any way.

[Example 1] Cream (formulation) (wt%) (1) Purified water 7.85 (2) Citric acid 0.1 (3) Sourium/Lium citrate 0.3 (4) Stearic acid 2.5 ( 5) Squalane 7.0 (6) Vaseline 5.0 (7) Hydrogenated oil 3.0 (8) Cetanol 2.0 (8) Stearyl alcohol 1.0 (10) Sorbitan sesquioleate 0.5 (11)
Diglycene isostearate 1.0 (12) Lipophilic glyceryl monostearate 1.0 (13) Polyoxyethylene (20) Hardened castor 1.0
Seed oil (14) Fragrance 0.3 (15) Polyoxyethylene monooleate 0.3 N (
20) Sorbitan (1B) N-stearoyl-L-glutamic acid 1.0 Sodium phosphate (17) Methylcellulose 0-1 (18) 1.3-Butylene glycol 10.0 (18)
) Glycerin 2.0 (20) Preservative 0.1 (21) Purified water Residue (manufacturing method) A Dissolve (1) to (3) by heating (75°C).

B(4) to (14) are heated and dissolved (75°C).

C(15) to (21) are heated and dissolved (75°C).

Add DA to B and emulsify.

Add ED to C to emulsify and cool to obtain a product.

[Example 2] Emulsion (formulation) (wt%) (+) Purified water 4.0 (2) 1.3-butylene gellicol 1.0 (3) Zinc sulfate 0.05 (4) Liquid paraffin 4.0 (5) Hydrogenated oil 2.0 (6) Cetano 0.5 (7) Stearic acid 0.3 (8) Starch fatty acid ester 0.8 (9) Polyoxyethylene (3) Castor oil 0.2 (10) Penta Erythritol fatty acid varnish 0.8 chill 5 (11) Glyceryl monostearate 0.5 (12)
-4 = Schiolein sorbitan 0.5 (13) Fragrance 0.1 (14) Carboxyvinyl polymer 0.1 (15) Storum alginate 0.05 (1B) N-balmitoylaspartic acid 0.2 sodium (17 ) Polyoxyethylene monolaurate 0.3 N (
20) Sorbitan (18) Sodium hydroxide 0.03 (18) Propylene glycol 5.0 (20) Preservative 0.1 (21) Purified water Residue (manufacturing method) A Dissolve (1) to (3) by heating ( 75℃).

B. Heat and melt (4) to (13) (75°C).

C(14) to (21) are heated and dissolved (75°C).

Add DA to B and emulsify.

Add ED to C to emulsify and cool to obtain a product.

6. Regarding the Examples obtained as described in 1-- below, the pH was measured and tests were conducted on stability and preparation rate of W10/W type emulsion. The pH was measured directly on the sample using a glass electrode pH meter.

In addition, the test was conducted immediately after li! under each temperature condition of 5°C, 30°C, and 40°C. ! The test was carried out after 1 month, 1 month later, and 3 months later. Note that the preparation rate is the actual W10/
This is the ratio of the internal aqueous phase of the W-type emulsion to the internal aqueous phase of the formulation, and the larger the value, the more preferable it is. The measurement results and test results are shown in Table 1.

(The following is a blank space) Table 1 As is clear from Table 1, the weakly acidic Wh of the examples of the present invention
The o/- type emulsified cosmetic has a slightly acidic pH, which is the pH of healthy bare skin, and was judged to have extremely excellent stability and preparation rate.

that's all Applicant: Kobayashi Corner Co., Ltd. 9 42-

Claims (3)

[Claims] (1) After mixing a lipophilic surfactant into the oil phase and then adding water to prepare a W10 type emulsion, the 111
Type 0 emulsion and aqueous phase are mixed with a woody surfactant and N-
A method for producing a weakly acidic W10/W type emulsified cosmetic, which is characterized by emulsifying in combination with a long-chain azilamic acid soap. (2) The lipophilic surfactant contains sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyethylene castor oil fatty acid ester, polyoxyethylene hydrogenated castor oil fatty acid ester, diglycerin fatty acid ester, pentaerythritol fatty acid ester, sucrose fatty acid ester. The method for producing a weakly acidic W10/W type emulsified cosmetic according to claim 1, which comprises one type or a combination of two or more types. (3) The wood-philic surfactant is polyglycerol hetanoyl fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene alkyl Ether, polyoxyethylene phytosterol, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, sucrose A method for producing a weakly acidic W10/W type emulsified cosmetic according to claim 1, which comprises one or a combination of two or more fatty acid esters.