Skin emulsion composition

Abstract

To provide an emulsion composition for skin that exhibits excellent emulsion stability, has a light touch during its application, spreads well on the skin, and gives a smooth use feeling without stickiness.SOLUTION: An emulsion composition for skin contains a component A: Centella asiatica leaf extract powder, a component B: dipotassium glycyrrhizinate, a component C: glycerol, and a component D: an oil solution that is liquid at 25°C. Preferably the emulsion composition further contains a component E: a water-soluble thickener.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an emulsified composition for skin.

Background Art

[0002] Conventionally, various surfactants have been widely used as emulsifiers in emulsified compositions for skin. An emulsified composition for skin emulsified using such a surfactant has a state in which moisture and oil are well mixed, and exhibits excellent effects not only in storage stability but also in usability such as skin affinity, extensibility, and moisturizing property. However, there is a problem that stickiness is easily felt depending on the type of surfactant used. In order to improve the usability, it is desirable to reduce the blending amount of the emulsifier or not to blend it. However, in an emulsified composition for skin emulsified without using a surfactant, there are various formulation design problems such as deterioration of storage stability over time and deterioration of usability.

[0003] Attempts have been made to produce an emulsified composition without using a surfactant. Specifically, for example, an emulsified cosmetic that does not contain a synthetic surfactant and uses only a small amount of a natural surfactant substance, which is stable, safe, and has good usability, has been proposed (see, for example, Patent Document 1). However, a cosmetic emulsified using only such a natural surfactant substance has a drawback that it is likely to feel heavy in touch when applied and has poor extensibility on the skin, resulting in a greater tendency to feel sticky.

[0004] On the other hand, a gel-type oil-in-water emulsified composition emulsified using an acrylic acid / alkyl methacrylate copolymer, which is widely used as a water-soluble thickener and does not contain a surfactant, has also been proposed (see, for example, Patent Document 2). However, an emulsified cosmetic composed of these components has a drawback that although it has good extensibility on the skin, it is difficult to obtain excellent moistness compared to an emulsified composition for skin emulsified using a surfactant.

[0005] Furthermore, skin emulsifying compositions that do not contain surfactants and utilize triterpenes have also been proposed (see, for example, Patent Document 3). However, in order to stabilize the emulsification, a high concentration of triterpenes is required, which results in very high production costs and presents a challenge in terms of practicality. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 5-004912 [Patent Document 2] Japanese Patent Publication No. 2012-111723 [Patent Document 3] Special Publication No. 2004-519411 [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, the present invention has been made in view of the prior art described above, and aims to provide a skin emulsifying composition that not only exhibits excellent emulsification stability, but also has a light feel when applied, good spreadability on the skin, and a smooth, non-sticky feel. [Means for solving the problem]

[0008] In other words, the present invention provides a skin emulsifying composition characterized by containing the following components A, B, C, and D. Ingredient A: Centella Asiatica Leaf Extract Powder Ingredient B: Dipotassium glycyrrhizinate Ingredient C: Glycerin Component D: Liquid oil at 25°C

[0009] The content of component A is preferably 0.1 to 3.0% by mass.

[0010] It is preferable that the ratio of the content of component B to component A (component B / component A) is in the range of 0.1 to 1.5.

[0011] It is preferable that component D is a hydrocarbon oil.

[0012] Furthermore, it is preferable that the following component E is included. Ingredient E: Water-soluble thickener

[0013] It is preferable that the above component E is two or three selected from hydroxyethylcellulose, carboxyvinyl polymer, and xanthan gum.

[0014] The skin emulsifying composition of the present invention preferably contains substantially no surfactants. [Effects of the Invention]

[0015] The skin emulsifying composition of the present invention, by satisfying essential constituent requirements, exhibits superior emulsification stability compared to conventional skin emulsifying compositions using surfactants and conventional skin emulsifying compositions without surfactants. Furthermore, it provides exceptionally remarkable effects such as a light feel upon application, excellent spreadability on the skin, and a non-sticky, smooth feel. [Modes for carrying out the invention]

[0016] Embodiments of the present invention will be described below.

[0017] The skin emulsifying composition of the present invention contains Centella asiatica leaf extract powder, dipotassium glycyrrhizate, glycerin, and an oil that is liquid at 25°C. In this specification, the above Centella asiatica leaf extract powder is referred to as "component A," the above dipotassium glycyrrhizate as "component B," the above glycerin as "component C," and the above oil that is liquid at 25°C as "component D."

[0018] The details of each component used in the skin emulsifying composition of the present invention are described below.

[0019] [Component A] The above-mentioned Component A is centella asiatica leaf extract powder. The centella asiatica leaf extract powder refers to a white solid powder (powder form) obtained by purifying an extract from the leaves of a plant of the Umbelliferae family called centella asiatica (scientific name: Centella asiatica).

[0020] The extraction method for obtaining the above-mentioned extract is not particularly limited, and various known extraction methods can be used. Also, the purification method for making the extract into powder is not particularly limited, and known methods for making powder can be used.

[0021] In the present invention, by using the above-mentioned centella asiatica leaf extract powder and combining it with the essential components of the present invention, not only can it be emulsified, but it can also exhibit extremely excellent emulsion stability. Also, compared with conventional skin-emulsified compositions using surfactants, a skin-emulsified composition with a light feel during application can be prepared. These excellent emulsion stability and usability can be sufficiently exhibited without using a large amount of the above-mentioned Component A. In the present invention, "a light feel during application" means a fresh and smooth feel, rather than a thick feel like a thick cream during application.

[0022] In the present invention, commercially available products can also be used as the above-mentioned Component A. Specific commercially available products of the above-mentioned Component A include, for example, the product name "Heteroside" (manufactured by Serdex), the product name "TECA" (manufactured by Bayer HealthCare SAS), etc.

[0023] The content of the above-mentioned Component A in the skin-emulsified composition of the present invention is not particularly limited as long as the desired effects can be exhibited. However, usually, from the perspective of exhibiting emulsion stability, it is preferably 0.1% by mass to 3.0% by mass, and more preferably 0.1% by mass to 1.5% by mass in 100% by mass of the composition.

[0024] [Component B] The above component B is dipotassium glycyrrhizinate. In the present invention, by using the above component B, it is possible to further enhance the excellent emulsification stability without impairing the feel during application.

[0025] In the present invention, component B may be a commercially available product. The commercially available component B is not particularly limited, whether it is a single raw material or a mixed raw material with other components, as long as the desired effect is achieved. Specific examples of commercially available products include the trade name "Glycinon K2" (manufactured by Tokiwa Botanical Chemical Research Institute Co., Ltd.) and the trade name "External Genuine Dipotassium Glycyrrhizinate" (manufactured by Maruzen Pharmaceutical Co., Ltd.).

[0026] The content of component B in the skin emulsifying composition of the present invention is not particularly limited as long as the desired effect can be achieved. However, from the viewpoint of further enhancing emulsification stability, it is generally preferable to have a content of 0.02% to 0.8% by mass, and more preferably 0.05% to 0.5% by mass, per 100% by mass of the composition. Note that the content of component B is the amount converted to pure content.

[0027] The ratio of the content of component B to component A in the skin emulsifying composition of the present invention (component B / component A) is not particularly limited as long as the desired effect can be achieved. However, from the viewpoint of further improving emulsification stability, it is preferable that the ratio be in the range of 0.1 to 1.5, and more preferably in the range of 0.2 to 1.0.

[0028] As described above, by using components A and B together, it is possible to further enhance emulsification without compromising the feel during application, compared to when component A is used alone. Furthermore, by using component C, which will be described later, in combination, it is possible to further improve the emulsification stability.

[0029] [Component C] The above component C is glycerin. In this invention, by using the above component C, the excellent emulsification stability can be further enhanced. In this invention, "glycerin" also includes "concentrated glycerin".

[0030] In the present invention, component C may be a commercially available product. The commercially available component C may be a single ingredient or a mixed ingredient with other ingredients, as long as the desired effect is achieved. Specific examples of commercially available products include the product name "Japanese Pharmacopoeia Concentrated Glycerin" (manufactured by Kao Corporation), the product name "Cosmetic Concentrated Glycerin" (manufactured by Sakamoto Pharmaceutical Co., Ltd.), and the product name "Concentrated Glycerin S" (manufactured by Shin Nippon Rika Co., Ltd.).

[0031] The content of component C in the skin emulsifying composition of the present invention is not particularly limited as long as the desired effect can be achieved. However, from the viewpoint of further enhancing emulsification stability, it is generally preferable that the content be 1.0% to 20.0% by mass, and more preferably 3.0% to 10.0% by mass, of 100% by mass of the composition. Note that the content of component C is the amount converted to pure content.

[0032] The skin emulsifying composition of the present invention, when using components A, B, and C in combination, can further enhance emulsification stability without impairing the feel during application, compared to when components A and B are used together.

[0033] As described above, by using components A, B, and C in combination, the present invention enables the preparation of a skin emulsification composition with high emulsification stability. Furthermore, compared to conventional skin emulsification compositions using surfactants, it is possible to prepare a skin emulsification composition with a lighter feel when applied.

[0034] [Component D] The above-mentioned component D is an oil that is liquid at 25°C. By using the above-mentioned component D, it is possible to improve the spreadability on the skin and provide a non-sticky, smooth feel. In this invention, "liquid at 25°C" refers to a state in which the product is fluid at 25°C.

[0035] Examples of component D include oils and fats, hydrocarbon oils, and fatty acid ester oils, which are liquid at 25°C. These components D may be used individually or in appropriate combinations of two or more types.

[0036] Specific examples of the above oils and fats include, for example, olive oil, sesame oil, rice bran oil, soybean oil, rapeseed oil, castor oil, sunflower oil, grape seed oil, cottonseed oil, kukui nut oil, wheat germ oil, evening primrose oil, macadamia nut oil, meadowfoam oil, and jojoba oil.

[0037] Specific examples of the hydrocarbon oils mentioned above include, for example, α-olefin oligomers, light isoparaffins, light liquid isoparaffins, synthetic squalane, vegetable squalane, squalane, liquid isoparaffins, and liquid paraffins.

[0038] Specific examples of the above fatty acid ester oils include, for example, isopropyl myristate, isopropyl palmitate, octyldodecyl myristate, octyl palmitate, isocetyl palmitate, octyl stearate, cetyl octanoate, stearyl octanoate, propylene glycol dicaprylate, di(caprylic / capric acid)propylene glycol, propylene glycol dicaprate, glyceryl trioctanoate, tri(caprylic / capric acid)glyceryl, and triethylhexanoin.

[0039] In the present invention, among the above-mentioned component D, it is preferable to use a hydrocarbon oil from the viewpoint of improving spreadability on the skin and providing a non-sticky, smooth, and better usability. Among hydrocarbon oils, it is more preferable to use squalane or liquid paraffin, and it is most preferable to use squalane.

[0040] In the present invention, component D may be a commercially available product. The commercially available component D is not particularly limited, whether it is a single raw material or a mixed raw material with other components, as long as the desired effect is achieved. Examples of commercially available squalane include the trade names "NIKKOL Sugar Squalane" (manufactured by Nikko Chemicals Co., Ltd.) and "Oryza Squalane" (manufactured by Oryza Oil & Fat Chemical Co., Ltd.).

[0041] The content of component D in the skin emulsifying composition of the present invention is not particularly limited as long as the desired effect can be achieved. However, from the viewpoint of improving spreadability on the skin and providing an excellent non-sticky, smooth feel, it is preferably 1.0% to 15.0% by mass, and more preferably 5.0% to 10.0% by mass, of 100% by mass of the composition. Note that the content of component D is the amount converted to pure content.

[0042] The skin emulsifying composition of the present invention preferably further contains a water-soluble thickener. In this specification, the water-soluble thickener is referred to as "component E".

[0043] [Component E] The above-mentioned component E is a water-soluble thickener. By using the above-mentioned component E, the emulsion stability can be further enhanced, and the feel when applied becomes lighter, the spreadability on the skin is excellent, and the non-sticky, smooth feel can be further improved.

[0044] Examples of component E include semi-synthetic polymers, synthetic polymers, and water-soluble natural polymers. These components E may be used individually or in appropriate combinations of two or more types.

[0045] Specific examples of the above-mentioned semi-synthetic polymers include, for example, sodium carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, ethylcellulose, sodium alginate, ester gum, nitrocellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, and crystalline cellulose.

[0046] Specific examples of the above-mentioned synthetic polymers include, for example, polyvinyl alcohol, sodium polyacrylate, carboxyvinyl polymer, (acrylates / alkyl acrylate (C10-30)) crosspolymer (acrylate / alkyl methacrylate copolymer), polyvinyl methylcellulose, and polyamide resin.

[0047] Specific examples of the above-mentioned natural polymers include, for example, xanthan gum, gum arabic, tragacanth gum, guar gum, locust bean gum, karaya gum, iris moss, quince seed, gelatin, shellac, rosin, and casein.

[0048] In the present invention, among the above-mentioned component E, it is preferable to use at least one selected from hydroxyethylcellulose, carboxyvinyl polymer, and xanthan gum, from the viewpoint of further enhancing emulsification stability, feel during application, spreadability on the skin, and a non-sticky, smooth feel. While the desired effects can be sufficiently achieved even with just one of these preferred components, it is most preferable to use two or three selected from hydroxyethylcellulose, carboxyvinyl polymer, and xanthan gum, from the viewpoint of maximizing the effects of the present invention.

[0049] In the present invention, component E may be a commercially available product. The commercially available component E may be a single raw material or a mixed raw material with other components, as long as the desired effect is achieved. Examples of commercially available hydroxyethylcellulose include the trade name "SANHEC M" (manufactured by Sansho Co., Ltd.). Examples of commercially available carboxyvinyl polymer include the trade name "CARBOPOL 980 POLYMER" (manufactured by Nippon Lubrizol Co., Ltd.). Examples of commercially available xanthan gum include the trade name "KELTROL CG-T" (manufactured by Sansho Co., Ltd.).

[0050] The content of component E in the skin emulsifying composition of the present invention is not particularly limited as long as the desired effect can be achieved. However, from the viewpoint of having excellent emulsification stability, a light feel when applied, excellent spreadability on the skin, and a smooth, non-sticky feel, it is generally preferable that the content be 0.1% to 2.0% by mass, and more preferably 0.2% to 1.0% by mass, of 100% by mass of the composition. Note that the content of component E is the amount converted to pure content.

[0051] The skin emulsifying composition of the present invention is preferably substantially free of surfactants, from the viewpoint of reducing stickiness and from the viewpoint of being able to prepare a good emulsifying composition without surfactants. In the present invention, a surfactant refers to a synthetic surfactant that does not exist in nature, which is a substance that has both a hydrophilic group and a lipophilic group in a single molecule and has excellent emulsifying power, solubilizing power and dispersing power.

[0052] In this invention, "substantially free of surfactants" means that surfactants are not added separately, and does not exclude even small amounts of surfactants contained in each ingredient.

[0053] [Other ingredients] In addition to the above-mentioned components, the emulsifying composition for skin of the present invention may appropriately contain, for example, plant extracts other than component A; anti-inflammatory agents other than component B; polyhydric alcohols other than component C; oils other than component D; thickeners other than component E; moisturizers, fragrances, pH adjusters, film-forming agents, chelating agents, lower alcohols, alkaline agents, vitamins, astringents, antioxidants, preservatives, UV absorbers, colorants, plant fermentation extracts, purified water, etc., depending on the purpose.

[0054] The properties of the skin emulsifying composition of the present invention are not particularly limited as long as it can exert the desired effect, but it is preferable, for example, to have a lotion-like or cream-like consistency.

[0055] The skin emulsifying composition of the present invention is not particularly limited to any form of emulsion, such as O / W emulsion (oil-in-water), W / O emulsion (water-in-oil), W / O / W emulsion (water-in-oil-in-water), or O / W / O emulsion (oil-in-oil-in-oil), as long as it can take the form of an emulsifier. However, from the viewpoint of excellent emulsification stability, a light feel when applied, and a significantly superior user experience, an O / W emulsion (oil-in-water) is preferred, and among these, an O / W emulsion (oil-in-water) prepared by the D-phase emulsification method is more preferred from the viewpoint of improving the user experience when spread. The method for preparing the O / W emulsion (oil-in-water) by the D-phase emulsification method is not particularly limited and can be prepared using known methods.

[0056] The skin emulsifying composition of the present invention is preferably used as a skin cosmetic because it exerts its effects when applied to the skin. Specifically, it is preferably used as a moisturizing cosmetic, a whitening cosmetic, an acne care cosmetic, or an anti-aging cosmetic aimed at suppressing wrinkles and sagging. Furthermore, the skin emulsifying composition of the present invention may take the form of cosmetics, quasi-drugs, designated quasi-drugs, or general merchandise.

[0057] The areas to which the skin emulsifying composition of the present invention is applied are not particularly limited, but as an example, it can be used on the face (forehead, around the eyes, corners of the eyes, cheeks, around the mouth, etc.), arms, elbows, back of the hands, fingertips, feet, knees, heels, neck, décolleté, armpits, back, etc. [Examples]

[0058] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. Unless otherwise specified, the amounts of each ingredient are expressed in "mass%".

[0059] (Sample preparation 1) According to the compositions listed in Tables 1 and 2, the skin emulsification compositions of Examples 1-5 and Comparative Examples 1-5 were prepared by conventional methods and subjected to the following evaluation. The results are shown in Tables 1 and 2. Note that all amounts in the tables are calculated on a pure content basis.

[0060] (Test Example 1: Evaluation of Emulsification Stability) Each sample from the examples and comparative examples was sealed in a 50 mL transparent glass container and stored in a 50°C constant temperature bath for 3 weeks. The state of the emulsion system after storage was visually observed and evaluated according to the following evaluation criteria.

[0061] <Evaluation Criteria for Emulsification Stability> ◎(Excellent): No change observed at all compared to immediately after preparation. ○ (Good): Although a slight decrease in viscosity is observed, there is almost no change. △ (Insufficient): Clear reduction in viscosity is observed. × (Defective): Has changed into a liquid state or has separated.

[0062] In the evaluation of emulsification stability in Test Example 1 above, each sample that received a result of "◎ (very good)", "○ (good)", or "△ (insufficient)" was subjected to the following tests.

[0063] (Test example 2: Evaluation of user experience) A 1g sample of the skin emulsified composition obtained in each example and comparative example was applied to the back of the hand for use testing. Sensory evaluations were conducted regarding "feel upon application," "spreadability," and "stickiness after application," and scores were assigned according to the following 1-5 point scale. The evaluations were conducted by five expert evaluators, and the final score was determined by a comprehensive assessment of each evaluator's evaluation.

[0064] The evaluation of "feel during application" was based on the lightness of the feel when applied, with higher scores given. The evaluation of "spreadability" was based on how well the product spread when applied, with higher scores given. The evaluation of "stickiness after spreading" was based on the absence of stickiness after spreading, with higher scores given for a smooth, non-sticky feel.

[0065] The evaluation was conducted according to the following five-level evaluation criteria. The results were calculated based on the average score of the expert evaluation panel, and a judgment was made according to the following criteria.

[0066] <Evaluation Criteria> 5 points: Very good 4 points: Good 3 points: Average 2 points: Defective 1 point: Very poor

[0067] <Judgment criteria> ◎: Average 4.0 points or more ○: Average score of 3.0 or higher but less than 4.0 △: Average score between 2.0 and 3.0 ×: Average score below 2.0

[0068] [Table 1]

[0069] [Table 2]

[0070] As is clear from the results in Table 1, Examples 1 to 5, which satisfy the essential components of the present invention, exhibit excellent emulsification stability, feel during application, spreadability during application, and stickiness after application. In other words, the skin emulsifying composition of the present invention not only provides excellent emulsification stability, a light feel during application, and a remarkably superior user experience, but also exhibits exceptionally remarkable effects that have not been achieved before, such as excellent spreadability on the skin and a smooth, non-sticky feel.

[0071] In contrast, Comparative Examples 1 to 4, which do not satisfy the essential components of the present invention, show that they do not exhibit sufficient emulsification stability. Furthermore, in Comparative Example 5, in which the essential component Centella asiatica leaf extract powder was replaced with birch bark extract, it was found that the excellent emulsification stability effect, which is a unique effect of the present invention, could not be exhibited.

Claims

1. A skin emulsifying composition that does not contain a surfactant, characterized in that it contains the following component A, component B, component C, and component D. Ingredient A: Centella asiatica leaf extract powder Ingredient B: Dipotassium glycyrrhizinate Ingredient C: Glycerin Component D: Liquid oil at 25°C

2. The skin emulsifying composition according to claim 1, characterized in that the content of component A is 0.1 to 3.0% by mass.

3. The skin emulsifying composition according to claim 1 or 2, characterized in that the ratio of the content of component B to component A (component B / component A) is in the range of 0.1 to 1.

5.

4. The skin emulsifying composition according to any one of claims 1 to 3, characterized in that the component D is a hydrocarbon oil.

5. Furthermore, the skin emulsifying composition according to any one of claims 1 to 4, characterized in that it contains the following component E. Ingredient E: Water-soluble thickener

6. The skin emulsifying composition according to claim 5, characterized in that the component E is two or three selected from hydroxyethylcellulose, carboxyvinyl polymer, and xanthan gum.

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