JPH11262653A - Oil-in-water type microemulsion and cosmetic containing tide same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil-in-water type microemulsion excellent in heating stability, aging stability and restoring property from a low temp. preservation and applicable to various oily materials and a cosmetic containing the same. SOLUTION: The microemulsion contains 0.1-30 wt.% poly-glycerine fatty acid ester type nonionic surfactant of a reaction product of a polyglycerine having an average polymerization degree of 5-15 with a fatty acid having >=75 wt.% oleic acid purity, 40-80 wt.% polyhydric alcohol, 0.1-20 wt.% oily material and 5-59.8 wt.% water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a stable oil-in-water microemulsion and a cosmetic containing the same.
More specifically, the present invention relates to an oil-in-water microemulsion which is excellent in heat stability, stability over time, and recoverability from low-temperature storage, and is applicable to various oily substances, and a cosmetic containing the same.

[0002]

2. Description of the Related Art In general, when oily substances such as fragrances, oil-soluble vitamins, ester oils, oils and fats, and hydrocarbon oils are blended with products which are liquid at room temperature among skin cosmetics and bath cosmetics, ethanol is used. And solubilization, dispersion or emulsification using a surfactant. However, in recent years, there are cases where it is not preferable to use ethanol in consideration of allergy and the like. In addition, surfactants include ionic surfactants and nonionic surfactants. Usually, from the viewpoint of safety, non-surfactants such as lecithin, polyoxyethylene sorbitan ester, polyoxyethylene hardened castor oil, and sucrose fatty acid ester are used. Ionic surfactants have been used.

However, when solubilizing, dispersing or emulsifying with the above-mentioned ethanol and a nonionic surfactant, the oily substance to be used is often restricted, and not only is it necessary to mix many surfactants, Separation and the like were likely to occur due to changes over time and changes in temperature. In particular, it has been difficult to stably blend a polar oil such as triglyceride. on the other hand,
A microemulsion is a micelle aqueous solution or micellar oil solution in which oil or water is solubilized by solubilization, and is known to be thermodynamically stable. When an oily substance is added to a cosmetic after forming a microemulsion, a stable system can be obtained by adding a small amount of a surfactant, which is particularly suitable for solubilizing the oily substance in a transparent lotion, bath agent and the like.

[0004] In microemulsions, generally unstable oily substances such as vitamin A, vitamin D, vitamin E, linoleic acid, docosahexaenoic acid and eicosapentaenoic acid are stored in a relatively stable state. Examples of the microemulsions that have been used in cosmetics include emulsions in which an ester oil and a nonionic surfactant are combined (Japanese Patent Application Laid-Open No. 63-126544) and specific oils and hydrophilic surfactants and alcohols. (JP-A-1-288330, JP-A-1-293131 and JP-A-6-4)
No. 0877) and an emulsion in which a polyglycerin polyoxyethylene butyl ether compound and an unsaturated aliphatic alcohol are combined (Japanese Patent Application Laid-Open No. 2-157035). However, the oily substance to be used is limited and the versatility is low. Separation and turbidity were easily caused by long-time heating and the like.

[0005]

An object of the present invention is to provide an oil-in-water microemulsion which is excellent in heat stability, aging stability and restorability from low-temperature storage, and is applicable to various oily substances. An object of the present invention is to provide a cosmetic containing the same.

[0006]

In order to solve the above-mentioned problems, researches have been repeated. As a result, by combining polyglycerol fatty acid ester having a specific composition, a polyhydric alcohol, an oily substance and water in a specific ratio, the objective is obtained. An oil-in-water microemulsion was obtained.

That is, the present invention provides: Average degree of polymerization is 5
Polyglycerin of 15 and oleic acid purity of 75% by weight
Polyglycerol fatty acid ester type nonionic surfactant which is a reaction product with a fatty acid having the above composition
0% by weight, b. 40-80% by weight of polyhydric alcohol, c.
0.1 to 20% by weight of an oily substance and d. Water 5-59.8
An oil-in-water microemulsion characterized by containing by weight, and a cosmetic containing the same.

[0008]

DETAILED DESCRIPTION OF THE INVENTION a. The average degree of polymerization of glycerin of the polyglycerin fatty acid ester type nonionic surfactant is 5 to 15, preferably 7 to 1.
3, more preferably 8 to 12. Average degree of polymerization is 5
If it is smaller, the hydrophilicity becomes stronger, so that it becomes difficult to form an oil-in-water emulsion, and if it is larger than 15, handling becomes extremely poor. Here, the average degree of polymerization of glycerin is determined by the hydroxyl value. For example, the hydroxyl value of decaglycerin having an average degree of polymerization of 10 is 890.

The fatty acid is oleic acid having a purity of 75% by weight.
It is preferably at least 80% by weight, more preferably at least 85% by weight. If the oleic acid purity is less than 75%, the stability over time and the heating stability of the microemulsion deteriorate. The reaction molar ratio of polyglycerin and fatty acid is polyglycerin / fatty acid = 0.8 / 1 to 1.5 /
1 is preferred, and more preferably 0.9 / 1 to 1./1.
3/1. If the molar ratio is less than 0.8 / 1, the lipophilicity becomes strong and an oil-in-water emulsion tends to be hardly formed. If the molar ratio is more than 1.5 / 1, polyglycerin is contained as an impurity in a large amount and the activator purity is increased. Is not preferred because of low

B. Used in the present invention. Polyhydric alcohols are compounds having two or more hydroxyl groups generally used in cosmetics, and include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol,
Dipropylene glycol, polypropylene glycol,
Examples thereof include 1,3-butylene glycol, glycerin, diglycerin, polyglycerin, sorbitol, and maltitol, and preferred are propylene glycol, dipropylene glycol, 1,3-butylene glycol, and glycerin.

C. Used in the present invention. The oleaginous substances are all oleaginous substances generally used in cosmetics from polar oils to non-polar oils, and there are natural and synthetic substances. Specifically, β-carotene, Atner dye, turmeric dye, shrimp dye, krill dye, marigold dye, oil-soluble dyes such as sicon dye, oil-soluble extracts such as oil-soluble licorice extract, menthol, eugenol, geraniol, essential oil, etc. Fragrances, oil-soluble vitamins such as vitamin A, vitamin D, vitamin E, antioxidants, ultraviolet absorbers, preservatives, bactericides,
Examples include natural oils and fats such as animal oils and vegetable oils, ester oils, hydrocarbon oils, silicone oils, fluorinated oils and the like, and preferred are fragrances, oil-soluble vitamins, ultraviolet absorbers and natural oils and fats.

D. Used in the present invention. Water is generally used for cosmetics, and includes, for example, purified water such as ion-exchanged water and distilled water, tap water, natural water, and alkaline ionized water.

According to the present invention, a. Component polyglycerin fatty acid ester type nonionic surfactant is 0.1 to 30% by weight, preferably 0.5 to 20% by weight in the total amount of the composition.
More preferably, the content is 1 to 15% by weight. If the amount is less than 0.1% by weight, both the heating stability and the stability over time are deteriorated. If the amount exceeds 30% by weight, not only gelation occurs but also
It is disadvantageous in terms of cost.

B. The polyhydric alcohol as a component is contained in the composition in an amount of 40 to 80% by weight, preferably 45 to 75% by weight, more preferably 50 to 70% by weight. 4
If it is less than 0% by weight, heat stability and restorability from low-temperature storage will be poor, and if it exceeds 80% by weight, stability over time will be poor.

C. The oily substance as a component accounts for 0.1 to 20% by weight, preferably 0.5 to 15% by weight, based on the total amount of the composition.
More preferably, the content is 1 to 10% by weight. If the amount is less than 0.1% by weight, the amount of the oily substance is too small, so that not only the effect of the present invention is not sufficiently exhibited, but also it becomes difficult to form an emulsion. Preparation becomes difficult.

D. The water component is 5 to 5 in the total amount of the composition.
9.8% by weight, preferably 5 to 54% by weight, more preferably 7 to 48% by weight. If it is less than 5% by weight, there is a problem in stability with time, and the upper limit is 59.8% by weight from the blending range of other components of the present invention.

[0017] The microemulsion of the present invention and the cosmetic containing it can be mixed with various additives within a range that does not impair the performance of the present invention. For example, polyoxyethylene alkyl ethers, nonionic surfactants such as polyoxyethylene sorbitan ester, alkyldimethylaminoacetate betaine, amphoteric surfactants such as alkylaminoacetate, acylmethyltaurine salt, alkyl ether sulfate, Anionic surfactants such as amide ether sulfates, water-soluble polymers such as xanthan gum, carboxyvinyl polymer, carboxymethylcellulose, hydroxypropylmethylcellulose and hydroxyethylcellulose, and pH adjusters such as acids and alkalis, inorganic salts and organic salts. Can be blended.

In the preparation of the microemulsion of the present invention, it is preferable to carry out a homogenization treatment with a homogenizer such as an ultra-high pressure homogenizer, a microfluidizer, a nanomizer, and an optimizer. 1000 kg /
It is preferable to perform the homogenization treatment at cm ² or more. Further, the amount of the microemulsion of the present invention to be added to cosmetics is not particularly limited, but is preferably 0.01% by weight or more, more preferably 0.1% by weight or more in consideration of the effect of the oily substance.

The cosmetics used in the present invention are all cosmetics and bath cosmetics directly used for skin and hair, and transparent ones are preferred. For example, lotion, body lotion, hair liquid, hair tonic, hair restorer, bath agent and the like.

[0020]

Next, the present invention will be described in more detail by way of examples. Examples 1 to 7 and Comparative Examples 1 to 10 Microemulsions shown in Tables 2 and 3 were prepared using polyglycerin fatty acid ester type nonionic surfactants shown in Table 1, and evaluated by the following methods. Was. The results are shown in Tables 2 and 3. The microemulsions shown in Tables 2 and 3 were prepared as follows. That is, a. A polyglycerin fatty acid ester type nonionic surfactant as a component, b. A polyhydric alcohol as a component and d. The mixture was mixed while adding water as a component, and completely dissolved. Add c. Mix while adding the oily substance as a component, and apply a uniform pressurization of 1500 kg / c with a microfluidizer (model: M-110E / H, manufactured by Mizuho Industry Co., Ltd.).
A homogenization treatment was performed at m ² and one pass to obtain a transparent microemulsion.

(1) Transparency The appearance of the emulsion at 25 ° C. was observed and evaluated according to the following three grades. In addition, the judgment was evaluated as で あ れ ば if ○ in both test conditions, △ if at least one of the conditions, and × if at least one was ×. ：: good transparency (a uniform transparent liquid) Δ: slightly poor transparency (uniform but slightly turbid) ×: poor transparency (cloudy or separated)

(2) Heating stability The sample was heated at about 80 ° C. for 30 minutes and at about 130 ° C. for 5 minutes. After cooling, the appearance was observed and evaluated by the following three grades. ：: good heating stability (uniform transparent liquid, no change in appearance) △: slightly poor heating stability (slightly separated or slightly turbid) ×: poor heating stability (white turbid or separated) )

(3) Stability over time The sample was sealed in a transparent glass container and kept at 0 ° C., 25 ° C. and 4 ° C.
The sample was stored in a constant temperature bath at 5 ° C. for one month, observed for its appearance, and evaluated according to the following three grades. ：: Good stability (transparent liquid under any temperature conditions, no change in appearance) △: Slightly poor stability (slightly separated or slightly turbid under any temperature conditions) ×: Stability Poor (coagulates or separates or becomes cloudy under any temperature conditions)

(4) Restorability from low-temperature storage After the sample is solidified at -20 ° C, the sample is left standing at room temperature for 6 hours to restore to a liquid state. After repeating this operation three times, the external appearance was observed and evaluated in the following three grades. ：: Good restorability (uniform transparent liquid, no change in appearance) △: Slightly poor restorability (thickening or slight separation or slight turbidity) ×: Poor restorability (solidification or Separates or becomes cloudy.)

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

From Examples 1 to 7, the microemulsions using the components of the present invention were excellent in heat stability, stability over time, and resilience from low-temperature storage. On the other hand, Comparative Examples 1 to
In No. 7, sufficient performance was not obtained. That is, Comparative Example 1
In Comparative Example 2, a. Since the components were replaced with nonionic surfactants other than those of the present invention and blended, heat stability and stability over time became poor. Since the components are blended beyond the scope of the present invention, they have solidified. In Comparative Example 4, a. Since the composition of the component polyglycerin fatty acid ester type nonionic surfactant is out of the range of the present invention, stability over time and resilience from low-temperature storage are deteriorated. In Comparative Example 5, b. Since the components are blended in less than the range of the present invention, not only do they gel slightly after preparation, but also the stability with time and the resilience from low-temperature storage are deteriorated. Since the components are blended beyond the range of the present invention, the stability over time is poor. Further, in Comparative Example 7, c. Since the components were blended beyond the scope of the present invention, they were completely clouded immediately after preparation.

Examples 8 to 14 Using the microemulsions of Examples 1, 2, 6, and 7, transparent lotions shown in Table 4 were prepared and evaluated by the following methods. Table 4 shows the results.

(1) Transparency The appearance of the lotion at 25 ° C. was observed and evaluated according to the following three grades. ：: good transparency (a uniform transparent liquid) Δ: slightly poor transparency (uniform but slightly turbid) ×: poor transparency (cloudy or separated)

(2) Stability over time Samples were stored at 5 ° C., 25 ° C. and 40 ° C. for one month, and their appearance was observed and evaluated according to the following three grades. ：: Good stability (transparent liquid under any temperature conditions, no change in appearance) △: Slightly poor stability (slightly separated or slightly turbid under any temperature conditions) ×: Stability Poor (separates or becomes cloudy under any temperature conditions)

(3) Restorability from low-temperature storage After the sample is solidified at -20 ° C, it is allowed to stand at room temperature for 6 hours to restore to a liquid state. After repeating this operation three times, the external appearance was observed and evaluated in the following three grades. ：: Good restorability (uniform transparent liquid, no change in appearance) △: Slightly poor restorability (slightly separates or slightly turbid) ×: Poor restorability (separates or becomes cloudy) From Table 4, all the lotions of Examples 8 to 14 were excellent in transparency, stability over time, and restorability.

[0033]

[Table 4]

Examples 15 to 21 Using the microemulsions of Examples 1, 3, 4 and 5, the transparent bath preparations shown in Table 5 were prepared and evaluated by the following methods. Table 5 shows the results.

(1) Transparency The appearance of the bath agent at 25 ° C. was observed and evaluated according to the following three grades. ：: good transparency (a uniform transparent liquid) Δ: slightly poor transparency (uniform but slightly turbid) ×: poor transparency (cloudy or separated)

(2) Stability over time The sample was stored at 5 ° C., 25 ° C. and 40 ° C. for one month, and its appearance was observed and evaluated according to the following three grades. ：: Good stability (transparent liquid under any temperature conditions, no change in appearance) △: Slightly poor stability (slightly separated or slightly turbid under any temperature conditions) ×: Stability Poor (separates or becomes cloudy under any temperature conditions)

(3) Restorability from low-temperature storage After the sample is solidified at -20 ° C, the sample is allowed to stand at room temperature for 6 hours to restore to a liquid state. After repeating this operation three times, the external appearance was observed and evaluated in the following three grades. ：: Good restorability (uniform transparent liquid, no change in appearance) △: Slightly poor restorability (slightly separates or slightly turbid) ×: Poor restorability (separates or becomes cloudy) From Table 5, all of the transparent bath agents of Examples 15 to 21 were excellent in transparency, stability with time, and restorability.

[0038]

[Table 5]

[0039]

The microemulsion of the present invention is excellent in heat stability, stability over time and resilience from low-temperature storage,
Applicable to many types of oily substances. Further, a clear lotion or clear bath agent containing the microemulsion is excellent in stability over time and restorability.

Claims (2)

[Claims] 1. A method according to claim 1, 0.1-30% by weight of a polyglycerol fatty acid ester type nonionic surfactant which is a reaction product of polyglycerin having an average degree of polymerization of 5 to 15 and a fatty acid having a composition of oleic acid purity of 75% by weight or more, b . 40-80% by weight of polyhydric alcohol, c. Oily substance 0.1-2
0% by weight and d. An oil-in-water microemulsion comprising 5 to 59.8% by weight of water. 2. a. 0.1-30% by weight of a polyglycerol fatty acid ester type nonionic surfactant which is a reaction product of polyglycerin having an average degree of polymerization of 5 to 15 and a fatty acid having a composition of oleic acid purity of 75% by weight or more, b . 40-80% by weight of polyhydric alcohol, c. Oily substance 0.1-2
0% by weight and d. A cosmetic comprising an oil-in-water microemulsion composed of 5 to 59.8% by weight of water.