HK1242587B - Oil-based cleansing cosmetics - Google Patents

Description

Oil-based makeup remover

Technical Field

The present invention relates to an oily makeup-removing cosmetic.

Background Art

Oil-based makeup removers, which utilize the dissolving action of oily ingredients to remove makeup impurities, are gaining widespread acceptance due to their reduced burden on the skin. Oil-based makeup removers primarily consist of oils and surfactants. Thickeners may also be added as needed. The mechanism of action of oil-based makeup removers is that the oily ingredients dissolve makeup impurities, which are then rinsed away with water through the action of surfactants. However, if the balance between the two ingredients and the amount of ingredients is poor, even if makeup impurities are dissolved, a strong greasy feeling may remain after rinsing. Furthermore, if this residual greasy feeling persists, further rinsing with a detergent is necessary to remove it. This excessive degreasing of the skin can lead to roughness and irritation.

Furthermore, the use of oil-based cleansing cosmetics in the shower is increasing. Therefore, it is desired to achieve a product that does not lose its cleansing power even when used with wet hands.

The applicant of the present application has invented an oil-based cleansing cosmetic material whose cleansing power does not decrease even when used with wet hands, and has obtained a patent (Patent Document 1, Non-Patent Document 1).

However, in response to recent cosmetics, there is a demand for oil-based cleansing products that offer enhanced cleansing power and minimize skin stress. Furthermore, it is noted that rinsing out oil-based cleansing products in hard water often becomes difficult, and a strong residual greasiness remains. Therefore, there is a demand for oil-based cleansing products that are effective even in hard water areas.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent No. 4145238

Non-patent literature

Non-Patent Document 1: "Development of Makeup Remover Oil Using Polyglycerol Fatty Acid Ester," Journal of the Japan Cosmetic Engineers Association (Journal of the Cosmetic Industry Association), Vol. 39, No. 3, 2005, pp. 186-194

Summary of the Invention

The present invention aims to provide an oily makeup-removing cosmetic material that has a strong makeup-removing effect on makeup dirt, leaves no residual greasy feeling, and is easy to rinse even in areas with hard water.

The present inventors have discovered that by combining two polyglycerol difatty acid esters and adding an oil, they have found that even when used with wet hands, the makeup removal ability is not reduced, and the product can be rinsed off with water. Furthermore, they have discovered that when polyoxyethylene sorbitan fatty acid esters and/or polyoxyethylene glycerol monoisostearate and dipolyglycerol monoisostearate are added as surfactants, the product can produce an oily makeup remover with no reduction in makeup removal ability, even in hard water environments (where hard water is used), which has traditionally been unsuitable for oily makeup removers.

That is, the main configuration of the present invention is as follows.

(1) An oily makeup-removing cosmetic comprising (A), (B), and (C),

(A): a polyglycerol difatty acid ester composed of a fatty acid having 8 to 10 carbon atoms and polyglycerol having an average degree of polymerization of 4 to 10,

(B): an esterified polyglycerol difatty acid ester consisting of a fatty acid having 18 to 22 carbon atoms and a polyglycerol having an average degree of polymerization of 8 to 15,

(C): Oil,

(A):(B) is 12:5 to 1:1.

(2) The oily makeup remover according to (1), wherein the polyglycerol difatty acid ester composed of a fatty acid having 8 to 10 carbon atoms and a polyglycerol having an average degree of polymerization of 4 to 10 is hexaglycerol dicaprate and/or hexaglycerol dicaprylate.

(3) The oily makeup remover according to (1) or (2), characterized in that the esterified polyglycerol difatty acid ester composed of a fatty acid having 18 to 22 carbon atoms and a polyglycerol having an average degree of polymerization of 8 to 15 is decapolyglycerol diisostearate and/or decapolyglycerol dioleate.

(4) The oily makeup remover according to any one of (1) to (3), wherein the oil is selected from one or more of 2-ethylhexanoate cetyl ester, methylphenyl polysiloxane, meadowfoam seed oil, and 2-hexyldecanol isostearate.

(5) The oily makeup remover according to any one of (1) to (4), further comprising (D): polyoxyethylene sorbitan fatty acid ester and/or polyoxyethylene glyceryl monoisostearate (30EO), and (E): diglyceryl monoisostearate.

(6) The oily makeup remover according to (5), characterized in that the polyoxyethylene sorbitan fatty acid ester is polyoxyethylene sorbitan monostearate (20EO) and/or polyoxyethylene sorbitan monooleate (20EO).

(7) The oily makeup remover according to (5) or (6), characterized in that when the particle size distribution of the emulsified particles produced by dilution with hard water having a hardness of 400 mg/L or more is measured, a maximum peak appears at 0.1 to 1 μm.

The oily cleansing cosmetic composition of the present invention maintains its cleansing power even when used with wet hands, and rinses clean without leaving residue on the skin. Furthermore, the oily cleansing cosmetic composition of the present invention maintains its cleansing performance even when used with water of high hardness. Therefore, even in hard water environments such as limestone regions, cleansing is possible without leaving any residual greasiness.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 shows the particle size distribution of emulsified particles when the oily makeup-removing cosmetic of Example 10 is diluted 60 times with water.

FIG2 shows the particle size distribution of the emulsified particles when the oily makeup remover of Example 10 is diluted 60 times with hard water having a hardness of 489 mg/L.

FIG3 is a graph showing the particle size distribution of emulsified particles when the oily makeup-removing cosmetic of Formulation Example 1 is diluted 60 times with ion-exchanged water.

FIG. 4 is a graph showing the particle size distribution of emulsified particles when the oily makeup remover of Formulation Example 1 is diluted 60 times with hard water.

FIG5 is an image showing the contact angle between the skin and a water droplet after washing with the oil-based cleansing cosmetic of Formulation Example 1. ...

FIG6 is an image showing the contact angle between the skin and a water droplet after washing with the oil-based makeup remover of Comparative Example 21. ...

FIG. 7 shows the particle size distribution of the emulsified particles when the oily makeup remover of Comparative Example 21 is diluted 60 times with ion-exchanged water.

FIG8 is an image showing the contact angle between skin and water droplets observed after washing with a commercially available oil-based makeup remover.

FIG. 9 is a graph showing the particle size distribution of the emulsified particle size of a 60-fold dilution of a commercially available oil-based makeup remover cosmetic material in a reference test example with hard water.

DETAILED DESCRIPTION

The present invention relates to an oily makeup-removing cosmetic, characterized in that, in the oily makeup-removing cosmetic containing (A), (B), and (C), (A) is a polyglycerol difatty acid ester composed of a fatty acid having 8 to 10 carbon atoms and a polyglycerol having an average degree of polymerization of 4 to 10, (B) is an esterified polyglycerol difatty acid ester composed of a fatty acid having 18 to 22 carbon atoms and a polyglycerol having an average degree of polymerization of 8 to 15, and (C) is an oil, and the ratio of (A): (B) is 12:5 to 1:1.

Hereinafter, the components of the present invention will be described.

<(A): Polyglycerol difatty acid ester composed of a fatty acid having 8 to 10 carbon atoms and polyglycerol having an average degree of polymerization of 4 to 10>

Component (A) used in the present invention is a surfactant, which is a polyglycerol difatty acid ester esterified with a fatty acid having 8 to 10 carbon atoms and a polyglycerol having an average degree of polymerization of 4 to 10. Specifically, hexapolyglycerol dicaprate and hexapolyglycerol dicaprylate are examples, and these can be used alone or in combination. The polyglycerol difatty acid ester of component (A) of the present invention is preferably blended in an amount of 9 to 12% by mass relative to the oil-based cleansing cosmetic.

<(B): Polyglycerol difatty acid ester composed of a fatty acid having 18 to 22 carbon atoms and polyglycerol having an average degree of polymerization of 8 to 15>

Component (B) used in the present invention is a surfactant, which is a polyglycerol difatty acid ester esterified with a fatty acid having 18 to 22 carbon atoms and a polyglycerol having an average degree of polymerization of 8 to 15. Specifically, decaglycerol diisostearate and decaglycerol dioleate are examples, and these can be used alone or in combination. The polyglycerol difatty acid ester of component (B) of the present invention is preferably blended in an amount of 5 to 8% by mass relative to the oil-based cleansing cosmetic.

In the present invention, component (A) is contained in a larger amount than component (B). In the oil-based cleansing cosmetic of the present invention, the ratio of (A):(B) is preferably 12:5 to 1:1. Within this composition range, the cleansing power is not reduced even when used with wet hands, and the product can be rinsed clean with water, leaving no greasy residue on the skin after rinsing.

<(C): Oil>

Examples of the (C) oil agent to be blended in the present invention include the following.

Examples include natural animal and plant oils and semi-synthetic oils, hydrocarbon oils, ester oils, glyceride oils, silicone oils, fat-soluble vitamins, higher fatty acids, and essential oil components of animals, plants, or synthesis. Examples of natural animal and plant oils and semi-synthetic oils include avocado oil, linseed oil, almond oil, olive oil, wheat germ oil, sesame oil, rice germ oil, rice bran oil, safflower oil, soybean oil, evening primrose oil, corn oil, rapeseed oil, horse fat, palm oil, palm kernel oil, castor oil, sunflower oil, jojoba oil, macadamia nut oil, coconut oil, hydrogenated coconut oil, peanut oil, and lanolin. Examples of hydrocarbon oils include squalane, squalene, liquid paraffin, and petrolatum. Examples of the ester oil include diisobutyl adipate, 2-hexyldecyl adipate, di-2-heptylundecanedioate, isostearyl isostearate, trimethylolpropyl triisostearate, cetyl 2-ethylhexanoate, neopentyl glycol di-2-ethylhexanoate, trimethylolpropyl tri-2-ethylhexanoate, pentaerythritol tetra-2-ethylhexanoate, cetyl octanoate, oleyl oleate, octyldodecyl oleate, decyl oleate, dicaprylic acid. Neopentyl glycol ester, 2-ethylhexyl succinate, isocetyl stearate, butyl stearate, diisopropyl sebacate, cetyl lactate, myristyl lactate, isopropyl myristate, octyl palmitate, 2-ethylhexyl palmitate, 2-hexyldecyl palmitate, 2-heptylundecanyl palmitate, 12-hydroxystearate cholesterol ester, phytosteryl oleate, diisostearate malate, p-methoxycinnamate, pentaerythritol rosin ester, etc. Examples of glyceryl esters include triisostearate, triisopalmitin, tri-2-ethylhexanoin, tri-tetradecanoin, and di-p-methoxycinnamic acid monoisooctanoin. Examples of the silicone oil include dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, octamethylcyclopentasiloxane, decamethylcyclohexasiloxane, diphenylsiloxyphenyl trimethicone, and stearoxypolysiloxane; higher alkoxy-modified polysiloxanes; alkyl-modified polysiloxanes; and higher fatty acid ester-modified polysiloxanes.

Among these exemplified ones, combination with cetyl 2-ethylhexanoate, methylphenyl polysiloxane, 2-hexyldecyl isostearate, octyl (octyl/decyl) octyl, and the like is preferred because the makeup removal effect is enhanced.

Furthermore, when blended in a small amount, meadowfoam seed oil exhibits a skin softening effect, which is therefore preferred.

From the viewpoint of cleansing power and flushability, the amount of the oily agent blended is preferably 10 to 90% by mass relative to the total amount of the oily cleansing cosmetic.

When components (A), (B), and (C) are further combined with one or more hydrophilic surfactants selected from polyoxyethylene sorbitan fatty acid esters and polyoxyethylene glyceryl monoisostearate (30EO) as component (D), and diglyceryl monoisostearate as component (E), the makeup removal function can be used even in hard water without being reduced (i.e., the function of maintaining the makeup removal effect even when used with wet hands and the function of being able to be washed off with water) and is therefore preferred.

<(D): Polyoxyethylene sorbitan fatty acid ester·Polyoxyethylene glyceryl monoisostearate (30EO)>

Component (D) is a hydrophilic surfactant, which is polyoxyethylene sorbitan fatty acid ester and/or polyoxyethylene glycerol monoisostearate (30EO). Polyoxyethylene sorbitan fatty acid esters are esters of sorbitol and fatty acids having 12 to 18 carbon atoms, to which ethylene oxide is added. Specific examples include polyoxyethylene sorbitan monostearate (20EO) and polyoxyethylene sorbitan monooleate (20EO).

The component (D) is preferably blended in an amount of 0.1 to 3% by mass, more preferably 1.2 to 3% by mass, based on the oil-based cleansing cosmetic.

<(E): Diglyceryl monoisostearate>

Diglyceryl monoisostearate is an ester of isostearic acid and diglycerol, and is typically used as a lipophilic solvent. In the present invention, the addition of diglyceryl monoisostearate can increase the amount of water solubilized in oily makeup removers. The amount of diglyceryl monoisostearate added to the oily makeup remover is preferably 0.1-3% by mass, more preferably 0.2-1% by mass.

In the present invention, when (D): polyoxyethylene sorbitan fatty acid ester and/or polyoxyethylene glyceryl monoisostearate (30EO) as a hydrophilic surfactant and (E): diglyceryl monoisostearate as a lipophilic solvent are blended at a ratio of (D): (E) of 1.7:1 to 3:0.4, the makeup removal function (i.e., the function of maintaining the makeup removal effect even when used with wet hands and the function of being able to be washed away with water) is not reduced even in hard water, and oily makeup dirt can be washed away smoothly.

<Optional Ingredients>

The oil-based cleansing cosmetic of the present invention may contain various raw materials commonly used in cosmetics as optional ingredients, as long as the effects of the present invention are not impaired. For example, polyols, thickeners, antioxidants, fragrances, etc. may be added.

Since polyols sometimes function as solvents, their inclusion may enhance cleansing power. In particular, inclusion of 1,2-pentanediol and dipropylene glycol is preferred because they enhance cleansing power.

Preferred examples of thickeners include stearoyl inulin and (behenic acid/eicosanedioic acid) glyceryl. The first purpose of including a thickener is to increase the viscosity to the desired level. The second purpose is to improve the evenness of the application, thereby making it smoother on the skin and making makeup removal easier. The unique viscosity can also improve the stickiness of surfactants and oils. The third purpose is to form a thin film when applied to the skin, preventing excessive friction on the skin, showing an irritation-suppressing effect, and thus improving safety. The thickener is preferably added in an amount of 0.01 to 3% by mass in the composition. When the amount is less than 0.01% by mass, it may sometimes be difficult to obtain the effect of improving evenness of application and the effect of alleviating irritation. When the amount is more than 3% by mass, precipitation may occur.

As the antioxidant, tocopherol can be mentioned.

The oil-based cleansing cosmetic of the present invention is designed in various dosage forms in consideration of usability and feel. Preferably, it can be in a liquid or gel form.

Example

The following examples, comparative examples, and test examples are given to further illustrate the features and effects of the present invention.

1. Preparation, Cleaning, and Flushing Effect Tests of Examples 1 to 4 and Comparative Examples 1 to 17 Combining Component (A): Hexaglycerol Dicaprate, Component (B): Decaglycerol Diisostearate or Decaglycerol Dioleate, and Component (C): Cetyl 2-Ethylhexanoate

The oil-based makeup remover cosmetics of Examples 1 to 4 were prepared using the compositions shown in Table 1, and the oil-based makeup remover cosmetics of Comparative Examples 1 to 17 were prepared using the compositions shown in Table 2. Examples 1 to 4 contain components (A) and (B) in a ratio of 12:5 to 1:1. Comparative Examples 1 and 2 contain components (A) and (B) in a ratio of 5:11.5. Comparative Examples 3 to 17 contain no component (A).

Table 1

Table 2

<Preparation method>

Each component was stirred and mixed while heating according to a conventional method to prepare a liquid oil-based makeup remover cosmetic.

<Evaluation Method>

The following test method was used to evaluate the makeup removal ability when used with wet hands and the feeling of no residual greasiness after rinsing with water.

[Evaluation of makeup removal function]

The following simple test method is widely used to evaluate makeup removal performance when used with wet hands and the absence of residual greasiness after rinsing. The present invention evaluated these two makeup removal functions using this test method. Sensory evaluation tests were also conducted.

(1) Simple test method

<Measurement of Water-Solubilizing Ability (Test for Evaluating "Makeup Removal Ability When Used with Wet Hands")>

The appearance of the oil-based makeup remover after adding water was observed, and the amount of water that could be solubilized in a transparent state was measured.

While stirring each oil-based makeup remover, water was added dropwise, and the amount of water until white turbidity appeared was measured.

Maintaining transparency even after adding water means that the composition does not become an O/W type emulsion (any of reverse micelle phase, lamellar liquid crystal phase, and bicontinuous microemulsion) even after mixing with water.

Since the oily components of oily cleansing cosmetics dissolve oily makeup dirt, it is important that the oil phase is continuous. In this evaluation method, the amount of water that can be solubilized in a transparent state is measured relative to 100% by mass of the oily cleansing cosmetic.

If transparency is maintained even with the addition of 20% by mass of water, the oil phase is continuous and the intended cleansing power is maintained. If the water addition amount is 15% by mass or less, the cleansing power is considered insufficient.

<Measurement of Emulsified Particle Size When Water is Added to Make an O/W Emulsified Composition (Test for Evaluating "No Residual Greasy Feeling After Rinsing with Water")>

The mechanism of action of oily makeup removers is that the oily components dissolve makeup impurities, which are then rinsed off with water through the action of surfactants. However, if this balance is poor, a residual greasiness may result, not from unremoved makeup impurities, but from the oily makeup remover itself remaining on the skin. This test is designed to predict the residual greasiness caused by the oily makeup remover remaining on the skin. Furthermore, if the test results are favorable, it can be predicted that the oily makeup remover can be used as a regular makeup remover without a residual greasiness.

An O/W emulsion composition was prepared by adding 60 times the amount of water as the oil-based makeup remover. The particle size distribution of the emulsified particles in this composition was measured using a Laser Particle Sizer 2000 (Malvern Instruments Ltd.) using laser diffraction. The volume-based average diameter was measured, and the peak shape of the particle size distribution was observed.

When the emulsified particle size is large, an oily feeling (residual greasiness) remains on the skin. However, when the emulsified particle size formed when water is added has a maximum peak at 1 μm or less, there is no residual greasiness after washing, and a refreshing cleansing feeling is achieved.

(2) Sensory evaluation test

<Makeup removal efficiency when using wet hands>

One skilled technician actually applied various oil-based makeup removers to skin coated with an oil-based makeup (lipstick) using hands wetted with water, and evaluated the makeup remover's effectiveness based on the following criteria.

○: Very good

△: Good

×: Defective

<No residual greasy feeling after washing with water>

This test was conducted to evaluate the residual greasiness of oil-based cleansing cosmetics after rinsing with water. Therefore, unlike the previous test, lipstick was not applied to the skin beforehand.

A skilled technician applied each oily cleansing cosmetic to the skin with hands wetted with water, and evaluated the residual greasiness (residual feeling) of the cleansing cosmetic on the skin after rinsing with water according to the following criteria.

○: No residual greasy feeling

△: There is a residual greasy feeling

(3) Results

The compositions of Examples 1 to 4 all demonstrated excellent makeup removal effectiveness. Furthermore, no residual greasiness remained after rinsing. The upper limit of water required to maintain the cosmetic's transparency was 20% by mass for Examples 1, 3, and 4, and 30% by mass for Example 2, allowing for extremely high addition capacities. Furthermore, when diluted 60-fold with water, the emulsified particles were extremely small, ranging from 0.2 to 0.8 μm. The results of these two tests confirmed excellent makeup removal effectiveness and the absence of residual greasiness when used with wet hands.

On the other hand, all the compositions in Comparative Examples 1 to 17 were rated poor for makeup removal when used with wet hands. Furthermore, only Comparative Example 2 received a rating of "○," indicating no residual greasiness after rinsing with water. The compositions in the other Comparative Examples all received a rating of "×," indicating a residual greasiness. This was confirmed to be due to the fact that even a small amount of water added resulted in an O/W emulsion, resulting in a cloudy appearance. Furthermore, upon 60-fold dilution with water, most of the composition separated without emulsification. Even when emulsified, the emulsified particles were as large as 7.566 μm, as shown in the results of Comparative Example 1.

Comparative Example 1 contains the essential ingredients (A), (B), and (C) of the present invention, but the makeup removal effect was poor when used with wet hands, and the result was a "poor" rating. A greasy feeling remained after rinsing with water. This is believed to be due to the fact that the ratio of components (A) to (B) was 5:11.5, with the proportion of component (B) exceeding that of component (A). Comparative Example 2 received a "positive rating" and no greasy feeling remained after rinsing with water, but the makeup removal effect was poor when used with wet hands, and the result was a "poor" rating. This is also believed to be due to the fact that the ratio of components (A) to (B) was 5:11.5, with the proportion of component (B) exceeding that of component (A).

Furthermore, Comparative Examples 10, 11, 15, 16, and 17 separated immediately after preparation and did not become homogeneous oily makeup remover cosmetics.

Based on the above test results, it is believed that in order to meet the essential requirements of an oily makeup remover cosmetic, namely, "makeup removal power when used with wet hands" and "no residual greasy feeling after rinsing with water," it is necessary to contain (A): a polyglycerol difatty acid ester composed of a fatty acid having 8 to 10 carbon atoms and a polyglycerol having an average degree of polymerization of 4 to 10, (B): an esterified polyglycerol difatty acid ester composed of a fatty acid having 18 to 22 carbon atoms and a polyglycerol having an average degree of polymerization of 8 to 15, and (C): an oil, and the ratio of (A): (B) should be between 12:5 and 1:1.

2. Further study of the ratio of (A) component: hexaglyceryl dicaprate and (B) component: decaglyceryl diisostearate

The above 1 clearly states that the ratio of component (A) to component (B) is crucial. To reconfirm this, oil-based cleansing cosmetics having the compositions of Examples 5 to 8 and Comparative Examples 18 to 21 shown in Table 3 below were prepared and evaluated under the same conditions as 1.

(1) Test composition

Table 3

The mixing ratios of component (A) to component (B) in Examples 5 to 8 were 12:5 for Example 5, 11:6 for Example 6, 10:7 for Example 7, and 9:8 for Example 8. Similarly, the mixing ratios for Comparative Example 18 were 13:4, 8:9 for Comparative Example 19, 6:11 for Comparative Example 20, and 4:13 for Comparative Example 21.

(2) Results

The lower part of Table 3 shows the evaluation results.

The compositions of Examples 5 to 8 all showed good makeup removal power and no residual greasy feeling after rinsing with water. The upper limit of the amount of water mixed in to maintain the cosmetic in a transparent state is 30% by mass for Examples 5 and 8, 40% by mass for Example 6, and 35% by mass for Example 7, allowing for extremely high addition capacities. In addition, when Examples 5 to 8 were diluted 60 times with water, the size of the emulsified particles was extremely small, at 0.3 to 0.7 μm. The results of these two sets of tests confirmed the sensory evaluation results of good makeup removal power when used with wet hands and no residual greasy feeling after rinsing with water.

On the other hand, the compositions of Comparative Examples 19-21 all received poor ratings for makeup removal and residual greasiness after rinsing with water. Furthermore, the upper limit of the amount of water required to maintain the cosmetic material in a transparent state was 15% by mass for Comparative Example 18, 5% by mass for Comparative Examples 19 and 20, and 0% by mass for Comparative Example 21, indicating a low solubilization amount of water. Furthermore, the emulsified particle size, when diluted 60-fold with water, was only 0.3 μm for Comparative Example 18; all other compositions exceeded 1 μm, with Comparative Example 21 exceeding 22 μm. The results of these two sets of tests directly confirmed the poor sensory evaluation results ("poor rating") for Comparative Examples 19-21 (makeup removal and residual greasiness). For Comparative Example 18, the upper limit of the amount of water required to maintain the cosmetic material in a transparent state was 15% by mass, resulting in a good makeup removal rating ("△"). This result suggests that the makeup removal performance of Comparative Example 18 may be reduced in actual use if excessive water is incorporated.

Combining the test results of 1. and 2., it can be seen that the mixing ratio of component (A) to component (B) in the oily makeup remover cosmetic of the present invention is crucial. From the perspective of obtaining an oily makeup remover cosmetic that has good makeup removal power when used with wet hands and does not leave a greasy feeling after rinsing with water, it is crucial to make the ratio between 12:5 and 1:1.

3. Preparation and testing of oil-based makeup removers with no loss of cleaning power in hard water environments (Part 1)

It is known that when oily makeup removers are used in hard water environments, their cleansing effect is reduced and rinsing becomes inadequate. This is believed to be because hard water causes the emulsified particles to aggregate. As a result, a residual greasy feeling remains even after rinsing with water. For example, in some areas of China, tap water has a hardness of over 400, resulting in the aforementioned reduced cleansing power and a residual greasy feeling after rinsing. As a composition for an oily makeup remover suitable for use in such extremely hard water areas, the present invention investigated compositions that, in addition to components (A), (B), and (C), further include polyoxyethylene sorbitan fatty acid esters and/or polyoxyethylene glyceryl monoisostearate (30EO) as component (D), and diglyceryl monoisostearate as component (E).

(1) Composition of Examples 9 to 11

The compositions shown in Table 4 below were prepared and tested assuming use in a hard water environment.

Table 4

(2) Test method

In addition to the test performed in 1. above, a dilution test using hard water having a hardness of 489 mg/L was similarly performed.

Furthermore, to confirm the presence of coarse particles caused by hard water, in addition to measuring the average particle size when diluted with hard water, the particle size distribution was also confirmed, and the presence of a maximum peak exceeding 1 μm in the particle size distribution was observed.

(3) Results

The compositions of Examples 9 to 11 all have very good makeup removal power, and there is no residual greasy feeling after rinsing with hard water. The upper limit of the amount of water that can be mixed in to maintain the cosmetic in a transparent state is 25% by mass in Examples 9 to 11, and a high volume of water can be mixed in. In addition, the size of the emulsified particles is 0.2 to 0.3 μm when diluted 60 times with water, and is extremely small even with hard water, at 0.3 to 0.6 μm. The results of these two groups of tests confirmed the good makeup removal power when used with wet hands and the absence of residual greasy feeling after rinsing with hard water. In addition, no maximum peak exceeding 1 μm was observed, which would cause discomfort such as residual greasy feeling during use. The maximum peaks of Examples 9 to 11 are all below 1 μm.

Figure 1 shows the particle size distribution of the oily makeup remover of Example 10 when diluted 60-fold with water, and Figure 2 shows the particle size distribution of the oily makeup remover of Example 10 when diluted 60-fold with hard water having a hardness of 489 mg/L. A comparison of the two distribution graphs reveals that the maximum peak of the emulsion particle distribution for the oily makeup remover of Example 10 occurs at 0.1-1 μm in both the water and hard water conditions.

That is, the oily cleansing cosmetics of Examples 9 to 11 do not cause aggregation of emulsified particles due to hard water and do not leave a residual greasy feeling, and therefore can be used in hard water areas without any problem.

4. Preparation and testing of oil-based makeup removers with no loss of cleaning power in hard water environments (Part 2)

(1) Composition of Examples 12 to 16

The compositions shown in Table 5 below were prepared and tested assuming use in a hard water environment.

Table 5

(2) Test method

A test using hard water having a hardness of 489 mg/L was carried out in the same manner as in the test (1).

Furthermore, to confirm the presence of coarse particles due to the incorporation of hard water, in addition to measuring the average particle size when diluted with hard water, the particle size distribution was also confirmed, and the presence of a maximum peak exceeding 1 μm in the particle size distribution graph was observed.

(3) Results

The compositions of Examples 12 to 16 all have excellent makeup removal properties and leave no residual greasiness after rinsing with hard water. The upper limit of the amount of water required to maintain the cosmetic's transparency is 30% by mass for Example 12, 20% by mass for Examples 13 and 14, 35% by mass for Example 15, and 20% by mass for Example 16, allowing for the inclusion of high volumes of water. Furthermore, when diluted 60-fold with water, the size of the emulsified particles is as small as 0.2 to 0.8 μm, with virtually no difference between water and hard water. Furthermore, no maximum peak exceeding 1 μm, which can cause an uncomfortable feeling of residual greasiness after rinsing with water, was observed.

The following shows a formulation example of an oil-based makeup-removing cosmetic further containing an optional component.

<Prescription Example>

Prescription Example 1 (Makeup Remover Oil)

Prescription Example 2 (Makeup Remover Oil)

Prescription Example 3 (Makeup Remover Gel)

The oil-based makeup removers of Formulation Examples 1 to 3 all had high makeup removal power, rinsed off quickly with water, and left no residual greasiness. Furthermore, their performance (makeup removal power, residual greasiness after rinsing) remained unchanged even with hard water.

<Dilution Test of Oily Makeup Remover of Prescription Example 1>

The oil-based makeup remover of Prescription Example 1 was diluted 60-fold with ion-exchanged water and hard water with a hardness of 489 mg/L to prepare an O/W emulsion composition. The particle size distribution of this composition was measured by laser diffraction using a Laser Particle Sizer 2000 (manufactured by Malvern Instruments Ltd.). The volume-based average diameter was measured, and the peak shape of the particle size distribution was observed.

The volume-based mean diameter when diluted with ion-exchanged water was 5.114 μm, while the volume-based mean diameter when diluted with hard water was 4.740 μm, with no discernible difference between the two. Furthermore, the particle size distribution of the emulsified particles when diluted with ion-exchanged water is shown in Figure 3, and the particle size distribution when diluted with hard water is shown in Figure 4.

Two maximum peaks appear in the particle size distribution diagram of Figure 3. The first peak that appears is the peak from the emulsion (oil droplet particles), which appears at 0.1 to 1 μm. The peak that appears at 1 to 10 μm after the maximum value is the peak from the oil-soluble thickener formulated as an optional component (the peak from (behenic acid/eicosandioic acid) glyceryl ester and stearoyl inulin). The positions of the two peaks do not change when diluted with ion exchange water or when diluted with hard water. Therefore, it can be confirmed from this test that even if an optional component is added as in Prescription Examples 1 to 3 of the present invention, the performance of the oil-based makeup remover will not change, and there will be no residual greasy feeling.

<Observation of the contact angle between skin and water droplets after washing with the oil-based makeup remover of Formulation Example 1>

The left upper arm was cleansed using the oily makeup remover of Prescription Example 1 over a 5 cm x 5 cm area and rinsed thoroughly with hard water. A single drop of ion-exchanged water was then added to the cleansed area. The resulting droplet, upon contact with the skin, was photographed and the contact angle observed. As a control, the oily makeup remover of Comparative Example 21 was used and similar observations were made.

Figure 5 shows the contact angle images of skin formed with water droplets when cleansed using Prescription Example 1, while Figure 6 shows the contact angle images of skin formed with water droplets when cleansed using Comparative Example 21. Comparison of the images in Figures 5 and 6 clearly shows that the skin after cleansing with Prescription Example 1 is in a so-called "hydrophobic" state, whereas the skin after cleansing with Comparative Example 21 is in a "water-infused" state. This means that in the case of Prescription Example 1, the oily makeup cleansing cosmetic material does not remain on the skin. On the other hand, it is believed that the oily makeup cleansing cosmetic material in Comparative Example 21 remains on the skin, and due to its surface activity, the water is absorbed into the skin.

The oily cleansing cosmetic of Comparative Example 21 was diluted 60-fold with ion-exchanged water, and the particle size distribution was measured, as shown in Figure 7. Since the maximum value of emulsified particles appeared in the range of 10 to 100 μm, it is believed that the oily cleansing cosmetic remained on the skin. On the other hand, since Formulation Example 1 did not show such a distribution maximum of emulsified particles, it is believed that the oily cleansing cosmetic was quickly rinsed off the skin.

<Reference Test Example>

Using a commercially available oil-based makeup remover, which was evaluated as leaving a residual greasy feeling in sensory testing, the left upper arm was cleansed over a 5cm x 5cm area, followed by thorough rinsing with hard water. A single drop of ion-exchanged water was added to the cleansed area, and the resulting droplet was photographed upon contact with the skin, with the contact angle observed.

The oil-based cleansing cosmetic was then diluted 60-fold with hard water to prepare an O/W emulsion composition. The particle size distribution of this composition was measured by laser diffraction using a Laser Particle Sizer 2000 (manufactured by Malvern Instruments Ltd.). The volume-based average diameter was measured and the peak shape of the particle size distribution was observed.

The photographed image of the contact angle is shown in Fig. 8 . The particle size distribution diagram is also shown in Fig. 9 .

The average particle size of this commercially available oily makeup remover when emulsified in water is as large as 17.277 μm, and a maximum peak appears at 1 to 10 μm in the distribution diagram of the emulsified particles.

The measured values of the contact angle and the particle size distribution revealed that the commercially available oil-based cleansing cosmetic had an unsatisfactory characteristic of being difficult to rinse with water.

Claims (7)

1. An oil-based makeup remover, characterized in that, in an oil-based makeup remover containing A, B, and C, A: Polyglycerol dicarboxylic acid esters are composed of fatty acids with 8 to 10 carbon atoms and polyglycerol with an average degree of polymerization of 4 to 10. B: Esterified polyglycerol difatty acid esters composed of fatty acids with 18-22 carbon atoms and polyglycerol with an average degree of polymerization of 8-15. C: Oil-based agent The ratio of A to B is 12:5 to 1:1. 2. The oil-based makeup remover according to claim 1, characterized in that the polyglycerol difatty acid ester composed of fatty acids with 8 to 10 carbon atoms and polyglycerol with an average degree of polymerization of 4 to 10 is hexaglycerol didecanoate and/or hexaglycerol dioctanoate. 3. The oil-based makeup remover according to claim 1 or 2, characterized in that the esterified polyglycerol difatty acid ester composed of fatty acids with 18 to 22 carbon atoms and polyglycerol with an average degree of polymerization of 8 to 15 is decaglycerol diisostearate and/or decaglycerol dioleate. 4. The oil-based makeup remover according to claim 1 or 2, characterized in that the oil is selected from one or more of 2-ethylhexanoate cetyl ester, methylphenyl polysiloxane, meadowfoam seed oil, and 2-hexyldecyl isostearate. 5. The oil-based makeup remover according to claim 1, characterized in that it further contains D: polyoxyethylene sorbitan fatty acid ester and/or polyoxyethylene glycerol monoisostearate (30EO), and E: dipolyglycerol monoisostearate. 6. The oil-based makeup remover according to claim 5, characterized in that the polyoxyethylene sorbitan fatty acid ester is polyoxyethylene sorbitan monostearate (20EO) and/or polyoxyethylene sorbitan monooleate (20EO). 7. The oil-based makeup remover according to claim 5 or 6, characterized in that, when measuring the particle size distribution of the emulsified particles produced by dilution with hard water with a hardness of 400 mg/L or higher, a maximum peak appears at 0.1 to 1 μm.