JPS5980326A - Preparation of w/o/w type emulsion - Google Patents

Abstract

PURPOSE:To prepare the titled emulsion excellent in stability, by a method wherein an S/O type emulsion obtained by dispersing a gel consisting of oleophilic surfactant and water in an oil phase is prepared and subsequently emulsified with a water phase. CONSTITUTION:A gel is formed from an oleophilic surfactant with an HLB value of 9 or less (e.g., sorbitan fatty acid ester) and water and dispersed in an oil phase such as a castor oil to obtain a W/O type emulsion which is, in turn, mixed and emulsified with a water phase to be brought to an external water phase. In preparing the gel in this process, when a proper amount of an acid (e.g., citric acid) and/or salts thereof are added, the formed gel becomes firm and, as the result, water droplets are stably held in dispersing said gel in the oil phase. In emulsifying the W/O emulsion and the external water phase in the above mentioned, when an emulsifier aid (e.g., cetanol) is added, it is stably oriented at the interface with the external water phase and the titled emulsion becomes more stable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a novel w/O/W emulsion, which has properties useful as a base in the fields of cosmetics, pharmaceuticals, foods, etc. Furthermore, the object of the present invention is to establish a method for producing a W/O/W type emulsion with excellent stability. In this specification, (7) W/O/W fi emulsion is also called multiple emulsion or composite emulsion, and its particle structure is similar to that of a normal O/W emulsion. While Nippon has a structure in which an oil phase is simply dispersed in an aqueous phase, it has a structure in which an aqueous phase is further dispersed in a separated oil phase. The external aqueous phase will be referred to as the external aqueous phase, and the internal aqueous phase further dispersed in this oil phase will be referred to as the internal aqueous phase.

Conventionally, W/O/ and W-type emulsions have been considered for application in fields such as cosmetics, pharmaceuticals, and foods due to their unique particle structure, and patents related to this have also been filed (Japanese Patent Publication No. 55 -25087, JP-A-52
-154029, JP-A-53-11578, JP-A-57
-15829, U.S. Pat. No. 2.399.263, British Pat.

However, the w10/
wBJ emulsions generally have poor stability, and this point has hindered their practical application. By the way, the reasons why W10/Wffl 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 phase containing the inner water phase Water movement due to osmotic pressure gradient occurs through the first phase, and finally the emulsified droplets are broken.
Ru.

■ 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 inventors of the present invention have conducted intensive research in order to eliminate the drawback of lack of stability and obtain a W/O/W type emulsion that is extremely excellent in practical use, and as a result, they have arrived at the present invention.

That is, 19 The method for producing a W/O/W emulsion according to the present invention first involves adding a lipophilic surfactant (II L
A gel is formed from water and a Tl value of 9 or less is preferred, and the gel is dispersed into an oil phase.
A W/O type emulsion is obtained by mixing (so-called gel emulsification method), and then the W/O type emulsion is mixed and emulsified with an aqueous phase to become an external aqueous phase. In the above process, when an appropriate amount of acid and/or its salts is added during gel preparation, the gel formed becomes strong, and even when this gel is soaked in an oil phase, water droplets do not form. In addition, in the second step, W/Offi
When an emulsifying agent is added during emulsification of the emulsion and the external aqueous phase, it is stably oriented at the interface with the external aqueous phase, making the W10/W type emulsion even more stable. Also,
When a water-soluble polymer is blended into the external aqueous phase, the water-soluble polymer acts as a retaining colloid for the emulsion and increases Wlo/
The stability of the Wg emulsion is further increased. Water-soluble polymers are also effective as feel improvers. Furthermore, the stability of the W10/W emulsion is increased by incorporating N-long chain acylamino acids or salts thereof into the external aqueous phase. Furthermore, by balancing the N-long chain acylamino acids and their salts, p11 control of the system becomes possible.

By the way, when producing the final W/0/W% emulsion from the W10 type emulsion and the external aqueous phase, the W10 type emulsion may be dispersed in the aqueous phase (so-called dispersion emulsification), or the W10 type emulsion may be dispersed in the aqueous phase (so-called dispersion emulsification). It is also possible to perform phase inversion by adding an external aqueous phase to the emulsion (so-called phase inversion emulsification).The possibility of two emulsification methods is a major feature of the present invention, and its utilization is The value is truly great.In the present invention, the reason why the fB production process can be freely selected is that the water droplets in the w/oq emulsion initially produced by the gel emulsification method are extremely fine. It is also uniform, and can maintain its morphology as a w10/w emulsion no matter how much of the emulsion with a grain size of l:4 is dried during subsequent emulsification into a W/O/W emulsion. This means that in the conventional method,
Compared to the fact that the water droplets in the initial W/O emulsion were coarse and non-uniform, so the yield was influenced by the 11°l diameter of the emulsion produced during subsequent emulsification into the W/O emulsion. That would be a great progress.

Various lipophilic surfactants (those with HL B of 9 or less) can be used in the present invention, including sorbitan fatty acid ester, glycerin fatty acid Nisdel, polyoxyethylene castor oil fat M ester, and hardened polymexyethylene. One type or a combination of two or more of castor oil fatty acid ester, diglyhyline fatty acid ester, pentaerythritol fatty acid ester, and sucrose fatty acid ester can be used, and the amount used can be 01 to 5 m%. That is, if the amount is less than 0.01% by weight, water cannot be retained in the oil and a W10/W type emulsion cannot be formed. Moreover, if it exceeds 5% by weight, the W/O/W type emulsion becomes oriented toward the "ll10f!1" emulsion, resulting in poor stability.

The water used for gel formation is 0.5 of the amount of lipophilic surfactant used.
~15 times the amount can be used. That is, if the amount is less than 0.5 times, the water content in the internal phase will decrease, and the advantages of the w10/wl emulsion will be lost. Moreover, if the amount is 15 times or more, the gel of the lipophilic surfactant and water becomes weak, resulting in poor stability.

Next, as the oil phase component, those that are usually used in the fields of cosmetics, pharmaceuticals, foods, etc. and are safe to the human body can be used. For example, vegetable oils such as olive oil and castor oil, waxes such as beeswax, lanolin, candelilla wax, and wood wax, hydrocarbons such as liquid paraffin, squalane, petrolatum, and paraffin wax, Nisdel oil, silicone oil, etc. can.

Examples of acids and their salts include citric acid, lactic acid, tartaric acid, malic acid, and pyrrolidone carvone rv! organic acids such as, and sodium salts, potassium salts, and triethanolamine salts of these organic acids, and can be used in amounts of 5% by weight or less. This will destroy the emulsion. In addition, by appropriately combining this acid and its salts, l:jl
, p II of the internal aqueous phase of the w10/wi emulsion can be freely selected. In other words, p of healthy bare skin
It has the advantage that it can be made weakly acidic.

In addition, as emulsifying aids, higher alcohols such as cetanol, sudearyl alcohol, behenyl alcohol, and cetostearyl alcohol, monoglycerides such as glyceryl monostearate and dawasserine monojleate, and higher fats such as stearic acid, palmitic acid, and myristic acid are used. Sharp,
Examples include α-monoglycerin ethers such as badyl alcohol-chimyl alcohol.

Examples of water-soluble polymers include carboxyvinyl polymer, polyvinyl alcohol, polyvinylpyrrolidone, guar gum, methyl cellulose, hydroxyethyl cellulose,
Examples of ON-long chain acylamino acids include gum arabic, sodium polyacrylate, sodium alginate, carrageenan, carboxymethyl cellulose, xanthan gum, etc. N-stearoylglutamic acid, N-valmitoylglutamic acid, N-myristoylglutamic acid, N- -Stearyl aspartic acid/N-
Examples include palmitoyl-spartic acid and N-myristoyl aspartic acid. Also, as the salts,
It may be a salt with any of the following bases.

Examples of basic substances include triethanolamine, sodium hydroxide, potassium hydroxide, arginine, lysine, hisdecine-ornithine, and oxylysine. N-
Incorporation of long-chain acylamino acids or salts thereof further contributes to stability. Furthermore, by appropriate blending or combination, W/O/
The pH of the external aqueous phase of the W-type emulsion can be freely selected. In other words, it has the advantage that it can be made slightly acidic, which is the pH of a healthy, bare-skinned egg.

To produce a W/4)/W type emulsion according to the present invention: (1) Add a predetermined amount of water to the lipophilic surfactant under stirring to form a gel. In this case, the acid and/or salt may be added to the water in advance.

■ Disperse the obtained gel in the oil phase using a stirrer, and
Obtain a mold emulsion. In this case, an emulsifying agent may be added to the oil phase.

■ The obtained W/O emulsion is added to the aqueous phase under stirring and dispersed, or if the external aqueous phase is added to the W/O emulsion and phase inversion emulsification is performed, W/O emulsion is dispersed.
/O/W type emulsion is obtained. In this case, W
In order to facilitate the formation of the 10/WW emulsion, an appropriate surfactant may be added in advance to the oil phase or external aqueous phase. The surfactant may be any nonionic, anionic, or cationic surfactant, regardless of its type. Additionally, adding a water-soluble polymer to the external aqueous phase further increases stability. Furthermore, when N-long chain acylamino acids or salts thereof are added to the external aqueous phase, stability is further increased and the pH of the external aqueous phase can be controlled.

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

These do not limit the present invention in any way.

[Actual 1 scale; Example 1] W/0/W type
■(Prescription)
(weight%) +I+ diglycerin diisoste
15T rate (2) Lactic acid 024 Sodium lactate 0.5 (4) Purified water 10 [1 (5) Squalane 100 (6) Setanol
40 (Casdearic acid monogly7-15lide (8) Monooleic acid polyoxy 10-thielene sorbitan (20E, 01) (9) Propylene glycol 10.0 (1)
1 spirit Vsu water 613 (11)
Anti-Pl agent Appropriate amount 0 thirst Fragrance
Add appropriate amounts (2) to (4) to A11) under stirring to form a gel.

B(5) to (8) are heated and dissolved at 70°C, and A is gradually added and dispersed.

Mix C(9) to 0υ and add B at 70°C to disperse and emulsify.

D (Add J71 and cool to make a product.

W/ 0 / Wi! obtained as above. J Cream E has a fresh feel similar to O/W type cream when applied on the desk, and after application it shows moisture retention comparable to W/O type cream, keeping the skin moist and stable. The performance was also good for a long period of time.

[Example 2] W / O / W type Riream ■ (Formulation) (Weight %) 0+ Didariserine diisoste 1.0 Arate (2) Citric acid 01 (3
: Sodium citrate 04(4)
Purified water 70 (5) Liquid paraffin 10.0 (6) A-leave oil 5.0 (7) Stearic acid 2.0 (8) Stearyl alcohol 2° (9) Stearic acid monoglycium +
o5ride al phosphoric acid sorbitol 1゜tanfll)' N -y, tyn yl-L -1
,0 Glutamic acid Oa*Sodium oxide. . 403
Propylene glycol 10.004+ Purified water 5996a! 9 Preservatives
Appropriate amount (If'9 fragrance
Appropriate amount (manufacturing method) Add (2) to (4) to A (1) with stirring to form a gel.

B (5) ~A1 is heated and dissolved at 7o''C, and A is gradually added and dispersed O a Ql) ~ (11 is mixed and Blc
Addition emulsification.

Add D 01 and cool to form a mass.

The weakly acidic W/O/W type cream ■ obtained in the above manner has a fresh feel similar to that of the 0/W type cream when applied on a desk, and has a fresh feel similar to that of the monthly W10 W1 cream. It had a rich texture, and after application, it showed moisture retention comparable to that of W10 type cream, kept the skin moist, and had good stability for a long period of time.

〔Example ! l] w/o/w type emulsion I (formulation) (wt%) (1) Diglycerin diisosde 0.57 rate + 21 Polyoxyethylene castor 02 oil (
3J O,) (3) Pyrrolidonecarboxylic acid 0.05(
4) Thorium pyrrolidone carboxylate (5) Purified water 6° (6
) Squalane 5゜(7)
Behenyl alcohol 1.0 (8) Palmibic acid 05 (9) Glycerol monostearate 0.5 phosphorus On Sorby schioleate 1.0 Tan 0 Li Vaseline 15 (1 ml)
Cured jli 7.0 (shima
1.3-butitone glyco-10,0L (1 season N-sudearoyl L-0,2 glutamic acid sodium hydroxide 0.o301;
) Carboxyvinyl polymer 010η Koto 1
'! ILisu water 7122 (
1υ Preservative: Appropriate amount 01 Flavor: Appropriate amount (11! Method) A III, Add (3) to “5” to (2) with stirring to form a gel.

B (61~02 70 C Nite addition 3S W solution L,
Gradually add and disperse A.

ao:'n- Cod is mixed, B is added at 70°C, and the mixture is dispersed and emulsified.

D　On is added and cooled to form a product.

The weakly acidic W/O/W type emulsion ■ obtained in the above manner spreads well and has a rich body when applied on a desk surface, which is unprecedented, and after application it retains moisture comparable to cream. It exhibited good properties, kept the skin moist, and had good long-term stability.

[Example 4] W/O/W type emulsion (formulation)
(% by weight) (1) Pentaerythritol fat o, 7 fatty acid ester (2) Lactic acid 0.1 (3
) Sodium lactate o4(4)
Purified water 70 (5) Glycerin fatty acid ester 1.0 l (6) Liquid paraffin 5° (7)
Hardened oil 1° (+1)
Vaseline 2゜(0) Allyl alcohol 1゜(ll '1-/
, t Re-(n7Qyli!J:411.0 siedilene sorbicun ('2flK, O,) (11) Propylene dalicol 10.00
Hot water N-Valmitoyl-L -0,5 Glutamic acid Qi T+ -7 Luginine o, 06I Methylcellulose 0.10!9 Sodium alginate 0.05 (10 Purified water
70.290η preservative
Appropriate amount (1) Fragrance Appropriate amount (
Manufacturing method) (2) to (4) are added to Δ111 under stirring to form a gel.

E (51~(IQ heated to 70'C), A
Add to t=M and disperse.

C01) - 0 marks are combined, and B is added at 70'C to disperse and emulsify.

D O! 1 and cooled to obtain a product.

The weakly acidic W/0/W type pore liquid ■ obtained as described above was as excellent as the W/O/W type pore liquid I.

Table 1 shows test results regarding stability and g', 'i production rate of W/O/W emulsion 1 for Examples. The preparation ratio is the ratio of the internal aqueous phase of the actual W/O/W emulsion to the prescribed internal aqueous phase, and the larger the value, the more preferable it is.

As is clear from Table 1 1!1, w/
The o/wil emulsion was determined to be generally excellent in stability and preparation rate.

Next, regarding the feeling of use, Examples 1 to 4 of Example 1a and Comparative Example 1
．． 2 was evaluated by a sensory test. The sensory test was conducted by a panel of 9 people on 6 items.
This was done using a 7-level needle price. The results are shown in Tables 2 and 3,
First, a comparative example will be described.

[Comparative example 13oz'w type cream (prescription) (% by weight) (1) Stearic acid 30 (2) Stearyl alcohol 3,5 (3) Stearic acid monoglyceride 5.0 Ride (4) Vaseline 25 (5)
) Hardened oil 10(6)
Liquid paraffin 100 (7) Monooleic acid polyoxylate 0.5 Sieglen sorbicun (7QE, O,) ())) Propylene glycol 10.0 (
9) Glycerin 3.0 (1 liter) Purified water 61.5 (11)
Preservatives Appropriate amount (13 fragrances
Appropriate amount (Raccoon 1 method) A Heat and dissolve (1) to (7) at 70°C.

B (8) to (11) are heated and dissolved at 70°C, and gradually added to A to emulsify.

a　Add Quri and cool it to make a product.

The O/W type mulberry cream of Comparative Example 1 was prepared as follows.

[Comparative Example 2) W10 type cream (formulation) (weight%) (1)
Lanolin 60 (21) Lanolin Alcohol 2.0 (3)
5.0 (4) Beeswax
10.0 (5) Ceresin wax
50(6) Stearic acid monoglyceride
30 rides (7) Liquid paraffin 12,0 (8
) Squalane 60(9)
Propylene glycol 5001 Borax
10αυ purified water
47.0 (preservatives)
Appropriate amount (1 East Flavor Appropriate amount (111!! method) Heat and dissolve A fil~(8) at 70°C.

B(9) to 0 are heated and dissolved at 70°C, and gradually added to A to disperse and emulsify.

a Add a3 and cool to obtain a product.

In the manner described above, Jb Comparative Example 2 W/O type cream was obtained.

Table 6 (as is clear from Tables 2 and 3) shows that the ly/
n / W Klj emulsion 1 obtained by the manufacturing method of
1WATAI1-Yaj↑'l i:t, [showed a feeling of use.

I"2 Deto] Person Kozai Co., Ltd. ±− 172-

Claims (1)

[Claims] +11 A W10 type emulsion obtained by dispersing a gel consisting of a lipophilic surfactant and water in an oil phase is
I! i! 1. A method for producing a W10/W type emulsion, which comprises emulsifying the W/O type emulsion and water one after another. (2) A method for producing a W10/W type emulsion according to claim 1, which comprises adding an acid and/or a salt thereof to a gel consisting of a lipophilic surfactant and water. (3) Acids include citric acid, lactic acid, tartaric acid, malic acid,
A method for producing a W/O/W type emulsion according to claim 2, which is pyrrolidone carboxylic acid. (4) The salts are of the acid shown in claim 3.
(5) According to claim In 2, which is a sodium salt, potassium salt, or triethanolamine salt, an emulsification aid is added to the oil phase when emulsifying the W10 type emulsion and the aqueous phase. A method for producing a W/O/W type emulsion according to claim 1. (6) The emulsifying aid is a higher alcohol such as cetanol, stearyl alcohol, behenyl alcohol, cetostearyl alcohol, monoglypeptide such as glyceryl monostearate or glycerin monooleate, or higher fatty acid such as stearic acid, valmitic acid, myristic acid, etc. W/O/W type Emma A according to claim 5, which is one or a combination of two or more of α-monoglycerin ethers such as 1-patyl alcohol and chimyl alcohol.
John's manufacturing method. (7) W/[]/W according to claim 1, characterized in that a water-soluble polymer is blended into the aqueous phase.
Method of manufacturing mold emulsion. (8) In the aqueous phase, the general formula is +1000-COH2)n-OH-0001t1 ROO-11H (wherein ROO does not represent a fatty acid residue of 12 to 26 carbons; n is 1 or 2). 2. A method for producing a W/O/W type emulsion according to claim 1, which comprises blending an N-long chain acylamino acid represented by the formula or a salt thereof.