W / O type Pickering emulsion and cosmetics containing the same

Abstract

To provide a W / O Pickering emulsion that is excellent in formulation stability and uniformity.SOLUTION: A W / O Pickering emulsion contains aqueous phase, oil phase, and hydrophobic powder, the W / O Pickering emulsion containing isostearic acid in combination with a nonvolatile oil solution with an IOB of 0.2 or more.SELECTED DRAWING: None

Description

Technical Field

[0006] , ,

[0001] The present invention relates to a W / O type Pickering emulsion and a cosmetic containing the same.

Background Art

[0002] In recent years, in the field of cosmetics, the utilization of Pickering emulsions has attracted attention. For example, Patent Document 1 proposes the addition of an acrylic acid polymer as a technique for improving the emulsion stability of a Pickering emulsion (Patent Document 1).

[0003] Here, when using a polar oil with a high IOB value such as an ultraviolet absorber, it is known that emulsification is difficult (Non-Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In view of the above prior art, an object of the present invention is to provide a W / O type Pickering emulsion having excellent formulation stability and formulation uniformity even in a form containing a non-volatile oil agent with an IOB of 0.2 or more. [Means for solving the problem]

[0007] In other words, the present invention, which solves the above problem, A W / O type Pickering emulsion comprising an aqueous phase, an oil phase, and a hydrophobic powder, The aforementioned W / O type Pickering emulsion is Isostearic acid and, In addition to isostearic acid, a non-volatile oil agent with an IOB of 0.2 or higher is also included. It is a W / O type Pickering emulsion containing [the specified ingredient]. The Pickering emulsion of the present invention exhibits excellent formulation stability and uniformity, even when it contains a non-volatile oil with an IOB of 0.2 or higher.

[0008] In a preferred embodiment of the present invention, the non-volatile oil agent with an IOB of 0.2 or higher is one or more oil agents selected from liquid oils and fats, solid oils and fats, waxes, hydrocarbon oils, higher fatty acids, higher alcohols, and ester oils. According to the above configuration, even in a form containing one or more non-volatile oils selected from liquid oils and fats, solid oils and fats, waxes, hydrocarbon oils, higher fatty acids, higher alcohols, and ester oils, it is possible to provide a Pickering emulsion that exhibits extremely excellent formulation stability and uniformity.

[0009] In a preferred embodiment of the present invention, the mass ratio of isostearic acid to the non-volatile oil agent with an IOB of 0.2 or higher is within the range of 1:0.5 to 1:25.

[0010] In a preferred embodiment of the present invention, the non-volatile oil agent with an IOB of 0.2 or higher is ethylhexyl methoxycinnamate.

[0011] In a preferred embodiment of the present invention, the hydrophobic powder is silylated silica.

[0012] A preferred embodiment of the present invention is characterized by containing 40% by mass or more of a volatile oil agent relative to the total amount of oil agent contained in the oil phase.

[0013] Further, the present invention for solving the above problems is a cosmetic containing the above-described W / O type pickering emulsion.

[0014] In a preferred form of the present invention, the cosmetic is a foundation or a sunscreen agent.

[0015] Further, the present invention is a method for producing a W / O type pickering emulsion containing an aqueous phase, an oil phase, and a hydrophobized powder, comprising a step of preparing an aqueous phase and a step of preparing an oil phase, wherein the oil phase contains isostearic acid and in addition to isostearic acid, a non-volatile oil agent having an IOB of 0.2 or more, and is also a method for producing a W / O type pickering emulsion.

Effect of the Invention

[0016] According to the present invention, even in a form containing a non-volatile oil agent having an IOB of 0.2 or more, a W / O type pickering emulsion excellent in formulation stability and formulation uniformity can be provided.

Mode for Carrying Out the Invention

[0017] <1> W / O type pickering emulsion The present invention is a W / O type pickering emulsion in which an aqueous phase and an oil phase are emulsified by a hydrophobized powder. And the present invention is characterized by containing isostearic acid and, in addition to isostearic acid, a non-volatile oil agent having an IOB of 0.2 or more.

[0018] ​​​​As shown in the examples described below, the W / O type pickering emulsion of the present invention may use a surfactant, but its content is preferably minimized as much as possible. The content of the surfactant is preferably 5% by mass or less, more preferably 1% by mass or less, still more preferably 0.1% by mass or less, and particularly preferably 0% by mass.

[0020] According to the present invention, even when the content of the surfactant is below the upper limit, it is possible to provide a W / O type pickering emulsion excellent in formulation stability and formulation uniformity.

[0021] The W / O type pickering emulsion of the present invention is suitable for external skin preparations. Among them, the W / O type pickering emulsion of the present invention is preferably used in cosmetics. Examples of cosmetics preferably include sunscreen agents, sunscreens, makeup bases, and foundations. Here, as the foundation, a liquid foundation is particularly preferably mentioned.

[0022] Hereinafter, the components contained in the W / O type pickering emulsion of the present invention will be described in detail.

[0023] (1) Hydrophobized powder In this specification, the hydrophobized powder refers to fine particles that act as an emulsifier by adsorbing at the interface between the oil phase and the water phase.

[0024] The fine particles in this specification can use any of inorganic powders such as silica, titanium dioxide, tin oxide, clay minerals, aluminum oxide, nano-fine particle precipitated calcium carbonate, coal, magnesium oxide, and magnesium trisilicate, and organic powders such as resin particles of ethyl cellulose, crystalline fatty alcohols and fatty acids, polystyrene, polymethyl methacrylate (PMMA), etc.

[0025] Moreover, it is preferable that the surface of the above-mentioned fine particles is hydrophobized. In this invention, a partially hydrophobic powder is also used, in which the surface of the fine particles is partially hydrophobicized.

[0026] Examples of hydrophobic treatments include treating powders with hydrophobic agents such as organosilicon compounds, silicones, hydrocarbon oils, fatty acids, fatty acid amides, fatty acid esters, higher alcohols, and polyoxyalkylene compounds. In particular, the hydrophobic treatment of fine particles is preferably carried out in a form in which an organosilicon compound or silicone is used as a hydrophobic agent to treat the powder.

[0027] Examples of organosilicon compounds include hexamethyldisilazane, monomethylsilane, dimethylsilane, trimethylsilane, trimethylethoxysilane, isobutyltrimethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, palmitylsilane, and the like.

[0028] Examples of silicones include dimethyl silicone, methylphenyl silicone, α-methylstyrene-modified silicone, chlorophenyl silicone, and fluorine-modified silicone.

[0029] Furthermore, one or a mixture of two or more hydrophobic agents can be used.

[0030] In the present invention, it is preferable to use silylated silica and / or hydrogen dimethicone-treated titanium dioxide as the hydrophobic powder. In particular, the hydrophobic powder is preferably silylated silica.

[0031] The particle size of the hydrophobic powder is preferably such that the average primary particle diameter is 200 nm or less, more preferably 100 nm or less, even more preferably 50 nm or less, more preferably 30 nm or less, and particularly preferably 15 nm or less. By setting the particle size of the hydrophobic powder within the above range, W / O type Pickering emulsion can be manufactured more reliably. By setting the particle size of the hydrophobic powder within the above range, the size of the emulsified particles can be adjusted to be smaller, thereby improving the stability of the formulation.

[0032] In this invention, the average primary particle diameter refers to the diameter of a primary particle measured by a method commonly used for particles, without any particular limitations. Specifically, the average primary particle diameter can be the arithmetic mean of the long and short axes of the particle, obtained from transmission electron microscope images.

[0033] The hydrophobic powder content is preferably 0.3% by mass or more, more preferably 0.4% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.7% by mass or more, and particularly preferably 0.9% by mass or more, based on the total amount of the W / O type Pickering emulsion.

[0034] Furthermore, the hydrophobic powder content is preferably 5% by mass or less, more preferably 4% by mass or less, more preferably 3% by mass or less, even more preferably 2.5% by mass or less, and particularly preferably 2% by mass or less, based on the total amount of the W / O type Pickering emulsion.

[0035] Furthermore, the hydrophobic powder content is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, per 10 parts by mass of water. Furthermore, the hydrophobic powder content is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, even more preferably 1 part by mass or less, and particularly preferably 0.5 parts by mass or less, per 10 parts by mass of water.

[0036] Furthermore, the hydrophobic powder content is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, even more preferably 0.1 parts by mass or more, and particularly preferably 0.2 parts by mass or more, per 10 parts by mass of oil.

[0037] Furthermore, the hydrophobic powder content is preferably 1 part by mass or less, and more preferably 0.8 parts by mass or less, per 10 parts by mass of the oil.

[0038] By keeping the hydrophobic powder content within the above range, a W / O type Pickering emulsion with excellent formulation stability and uniformity can be provided.

[0039] (2) Isostearic acid The present invention is characterized by the use of isostearic acid.

[0040] The isostearic acid content is preferably 0.8% by mass or more, more preferably 1% by mass or more, more preferably 1.2% by mass or more, even more preferably 1.5% by mass or more, and particularly preferably 1.8% by mass or more, based on the total amount of the W / O type Pickering emulsion.

[0041] Furthermore, the isostearic acid content is preferably 15% by mass or less, more preferably 12% by mass or less, more preferably 11% by mass or less, even more preferably 8% by mass or less, and particularly preferably 6% by mass or less, based on the total amount of the W / O type Pickering emulsion.

[0042] Furthermore, the mass ratio of isostearic acid to hydrophobic powder is preferably within the range of 1:0.1 to 1:10, more preferably 1:0.2 to 1:5, more preferably 1:0.3 to 1:2, and even more preferably 1:0.5 to 1:1.

[0043] By keeping the isostearic acid content within the above range, a W / O type Pickering emulsion with excellent formulation stability and uniformity can be provided.

[0044] Here, isostearic acid is preferably in a form contained in the oil phase.

[0045] (3) Oil phase components The W / O type Pickering emulsion of the present invention contains an oil as an oil phase component. The oil content is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, based on the total amount of the W / O type Pickering emulsion.

[0046] Furthermore, the oil content is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 50% by mass or less, relative to the total amount of the W / O type Pickering emulsion.

[0047] By keeping the oil content within the above range, a W / O type Pickering emulsion with excellent formulation stability and uniformity can be provided.

[0048] The W / O type Pickering emulsion of the present invention preferably contains both a volatile oil and a non-volatile oil.

[0049] (3-1) Non-volatile oils A more preferred form of the non-volatile oil agent used in the W / O type Pickering emulsion of the present invention will be described below.

[0050] Examples of non-volatile oil agents used in the present invention include liquid oils and fats, solid oils and fats, waxes, hydrocarbon oils, higher fatty acids, higher alcohols, ester oils, silicone oils, and the like.

[0051] Furthermore, the W / O type Pickering emulsion of the present invention contains a non-volatile oil agent with an IOB value of preferably 0.2 or higher, more preferably 0.25 or higher. When using such highly polar oils, it was difficult to prepare a stable W / O type Pickering emulsion using conventional methods. According to the present invention, even when using a non-volatile oil agent having the above IOB value, a W / O type Pickering emulsion with excellent emulsification stability can be prepared.

[0052] Here, the non-volatile oil agent having the above IOB value is preferably one or more oil agents selected from liquid oils and fats, solid oils and fats, waxes, hydrocarbon oils, higher fatty acids, higher alcohols, and ester oils.

[0053] The content of the non-volatile oil agent having the above IOB value is preferably 0.8% by mass or more, more preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and particularly preferably 8% by mass or more, based on the total amount of the W / O type Pickering emulsion.

[0054] Furthermore, the content of the non-volatile oil agent having the above IOB value is preferably 50% by mass or less, more preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, and particularly preferably 10% by mass or less, relative to the total amount of the W / O type Pickering emulsion.

[0055] Furthermore, the mass ratio of the hydrophobic powder to the non-volatile oil agent having IOB within the above range is preferably in the range of 1:0.5 to 1:40, more preferably 1:1 to 1:30, more preferably 1:1.5 to 1:20, and even more preferably 1:2 to 1:10.

[0056] The mass ratio of isostearic acid to the non-volatile oil having IOB within the above range is preferably in the range of 1:0.5 to 1:25, more preferably 1:1 to 1:20, more preferably 1:2 to 1:15, and even more preferably 1:3 to 1:10.

[0057] By keeping the content of the non-volatile oil agent within the above range, it is possible to provide a W / O type Pickering emulsion with excellent formulation stability and uniformity.

[0058] Here, the non-volatile oil agent having the above IOB value is preferably an ultraviolet absorber.

[0059] Non-volatile oils include propylene glycol meisostearate (IOB value: 0.4), diethylhexyl sebacate (IOB value: 0.24), 2-ethylhexyl paramethoxycinnamate (IOB value: 0.28), trimethylpropane tri-2-ethylhexanoate (IOB value: 0.31), di-2-ethylhexyl succinate (IOB value: 0.32), di(caprylic / capric acid) propylene glycol (IOB value: 0.32), 2-ethylhexyl 2-cyano-3,3-diphenylacrylate (IOB value: 0.33), and tri(caprylic / capric acid) glyceryl (IOB value: 0.33), Trimethylolpropane trioctanoate (IOB value: 0.33), Glyceryl tricaprylate (IOB value: 0.33), Ethylene glycol dioctanoate (IOB value: 0.35), Glyceryl dimyristate (IOB value: 0.35), Diethylene glycol dilaurate (IOB value: 0.35), Pentaerythritol tetra-2-ethylhexanoate (IOB value: 0.35), Glyceryl monostearate diacetate (IOB value: 0.36), Propylene glycol monostearate (IOB value: 0.38), Propylene glycol oleate Recall (IOB value: 0.39), Oleyl lactate (IOB value: 0.39), Propylene glycol dicaproate (IOB value: 0.4), Ethylene glycol monostearate (IOB value: 0.4), Diethylene glycol dicaprate (IOB value: 0.41), Glyceryl coconut oil fatty acid (IOB value: 0.41), Glyceryl dilaurate (IOB value: 0.41), Glyceryl sesquioleate (IOB value: 0.41), Ethylene glycol monooleate (IOB value: 0.41), Coconut oil alcohol (IOB value: 0.42), Lauryl alcohol (I IOB value: 0.42), cetyl lactate (IOB value: 0.42), diethyl sebacate (IOB value: 0.43), methyl castor oil fatty acid (IOB value: 0.43), ethylene glycol palmitate (IOB value: 0.44), polyethylene glycol dilaurate (IOB value: 0.45), and tripylene glycol dipivalate (IOB value: 0.52), ethylhexyl methoxycinnamate (IOB value: 0.28), isononyl isononanoate (IOB value: 0.2), octyldodecanol (IOB value: 0.26), diisostearyl malate (IOB value: 0.28) It may also be one or more selected from the group consisting of: 28) Phytosteryl / octyldodecyl laurolyl glutamate (IOB value: 0.30), caprylic / capric triglyceride (IOB value: 0.33), 2-ethylhexyl hydroxystearate (IOB value: 0.31), propylene glycol dicaprylate (IOB value: 0.32), glyceryl tri-2-ethylhexanoate (IOB value: 0.35), octyldodecyl lactate (IOB value: 0.35), diisopropyl sebacate (IOB value: 0.40), and castor oil (IOB value: 0.43).

[0060] (3-2) Volatile oils A more preferred form of the volatile oil agent used in the W / O type Pickering emulsion of the present invention will be described below.

[0061] The W / O type Pickering emulsion of the present invention contains a volatile oil agent in an amount of preferably 10% by mass or more, more preferably 20% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, based on the total amount of oil agent.

[0062] Furthermore, the W / O type Pickering emulsion of the present invention contains a volatile oil agent in an amount of preferably 95% by mass or less, more preferably 92.5% by mass or less, more preferably 90% by mass or less, even more preferably 87.5% by mass or less, and particularly preferably 85% by mass or less, based on the total amount of oil agent.

[0063] By keeping the content of volatile oils within the above range, a W / O type Pickering emulsion with excellent formulation stability and uniformity can be provided.

[0064] The following describes in detail more preferred forms of the oil component contained in the W / O type Pickering emulsion of the present invention.

[0065] Preferred volatile oils include volatile silicone oils, volatile hydrocarbon oils, volatile ester oils, volatile natural animal and vegetable oils, and volatile fluorine oils, with volatile silicone oils and volatile hydrocarbon oils being particularly preferred.

[0066] Preferred examples of the aforementioned volatile silicone oils include dimethylpolysiloxane, methyl trimethicone, tris(trimethylsilyl)methylsilane, tetrakis(trimethylsilyl)silane, hexacyclotrisiloxane, octamethyltetracyclosiloxane, cyclopentasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and tetradecamethylcycloheptasiloxane.

[0067] Examples of the aforementioned volatile hydrocarbon oils include decane, undecane, dodecane, tridecane, isooctane, isodecane, isododecane, isohexadecane, cyclodecane, and cyclododecane.

[0068] (4) Water phase components The water content in the aqueous phase of the W / O type Pickering emulsion of the present invention is preferably 5% by mass or more, more preferably 25% by mass or more, even more preferably 35% by mass or more, particularly preferably 40% by mass or more, and most preferably 45% by mass or more.

[0069] Furthermore, the water content in the aqueous phase is preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, and particularly preferably 80% by mass or less.

[0070] The water content is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.2 parts by mass or more, even more preferably 0.4 parts by mass or more, and particularly preferably 0.5 parts by mass or more, based on 1 part by mass of the total amount of oil described above. The water content is preferably 2 parts by mass or less per 1 part by mass of the total amount of the oil described above.

[0071] Furthermore, the water content is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.2 parts by mass or more, and even more preferably 0.5 parts by mass or more, per 1 part by mass of the volatile oil.

[0072] The water content is preferably 5 parts by mass or less, more preferably 4 parts by mass or less, even more preferably 3 parts by mass or less, and particularly preferably 2.5 parts by mass or less, per 1 part by mass of the volatile oil.

[0073] The content of the total aqueous phase relative to the total amount of W / O type Pickering emulsion is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, particularly preferably 20% by mass or more, and most preferably 30% by mass or more.

[0074] Furthermore, the content of the total aqueous phase relative to the total amount of W / O type Pickering emulsion is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, particularly preferably 60% by mass or less, and most preferably 55% by mass or less.

[0075] The aqueous phase in the W / O type Pickering emulsion of the present invention may contain any ingredients commonly used in cosmetics without particular limitations, but it is preferable to contain, for example, the following ingredients.

[0076] Examples of polyols include polyethylene glycol, glycerin, 1,3-butylene glycol, erythritol, sorbitol, xylitol, maltitol, propylene glycol, dipropylene glycol, diglycerin, isoprene glycol, 1,2-pentanediol, 2,4-hexylene glycol, 1,2-hexanediol, and 1,2-octanediol, among which glycerin, 1,3-butylene glycol, and sorbitol are preferred. The content of these components is preferably 0.5% by mass or more, more preferably 3% by mass or more, of the total W / O type Pickering emulsion. Furthermore, the polyol content is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0077] Furthermore, the W / O type Pickering emulsion of the present invention may contain a thickening agent. Preferred thickening agents include xanthan gum, gellan gum, guar gum, quince seed, carrageenan, galactan, gum arabic, pectin, mannan, starch, curdlan, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, methylhydroxypropylcellulose, chondroitin sulfate, dermatan sulfate, glycogen, heparan sulfate, hyaluronic acid, sodium hyaluronate, tragacanth gum, keratan sulfate, chondroitin, mucoitin sulfate, hydroxyethyl guar gum, carboxymethyl guar gum, dextran, kerato sulfate, locust bean gum, succinoglucan, caronic acid, chitin, chitosan, carboxymethyl chitin, agar, polyvinyl alcohol, polyvinylpyrrolidone, carboxyvinyl polymer, sodium polyacrylate, polyethylene glycol, sodium acrylate grafted starch, stearoxyhydroxypropyl methylcellulose, bentonite, and the like.

[0078] The thickening agent content is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, of the total W / O type Pickering emulsion. The thickening agent content is preferably 5% by mass or less, more preferably 1% by mass or less, of the total W / O type Pickering emulsion.

[0079] (5) Other ingredients In the W / O type Pickering emulsion of the present invention, in addition to the above-mentioned components, optional components commonly used in cosmetics may be included, to the extent that they do not impair the effects of the invention.

[0080] <2> Method for producing W / O type Pickering emulsion The W / O type Pickering emulsion of the present invention can be produced by the following manufacturing method. First, the process includes the steps of preparing an aqueous phase containing the aforementioned optional components in appropriate amounts, and preparing the aforementioned oil phase.

[0081] In this invention, the oil phase is characterized by containing isostearic acid and a non-volatile oil agent with an IOB of 0.2 or higher. Furthermore, in a preferred embodiment of the present invention, the oil phase comprises an oil agent and a hydrophobic powder, wherein the oil agent comprises 40% by mass or more of a volatile oil agent relative to the total amount of the oil agent.

[0082] Next, by mixing the aqueous phase and the oil phase, emulsification of the aqueous phase and the oil phase occurs due to the hydrophobic powder, and the W / O type Pickering emulsion of the present invention is produced.

[0083] The W / O type Pickering emulsion of the present invention, and cosmetics containing it, maintain an emulsified state when stored in a container, with the powder present at the interface between the aqueous and oil phases.

[0084] Preferred embodiments of the method for producing a W / O type Pickering emulsion of the present invention can be described by reference to the above description. [Examples]

[0085] <Test Example 1> In Test Example 1, the effect of isostearic acid was confirmed in a W / O type Pickering emulsion containing a non-volatile oil agent with an IOB of 0.2 or higher.

[0086] (1) Manufacturing of emulsified composition The aqueous and oil phases listed in Table 1 below were prepared, and by mixing and emulsifying them, a W / O type Pickering emulsion was obtained.

[0087] Here, Examples 1-3 and 5-7 are W / O type Pickering emulsions containing silylated silica (corresponding to the hydrophobic powder in the present invention), isostearic acid, and ethylhexyl methoxycinnamate (ultraviolet absorber; corresponding to the non-volatile oil agent with an IOB of 0.2 or higher in the present invention). In Example 4, the other hydrophobic powder used is a W / O type Pickering emulsion using hydrogen dimethicone-treated titanium dioxide.

[0088] Here, as Comparative Example 1, a W / O type emulsion composition (not a W / O type Pickering emulsion) was prepared using a surfactant (silicone-based surfactant) instead of a hydrophobic powder. In addition, a W / O type Pickering emulsion containing silylated silica (corresponding to the hydrophobic powder in the present invention) but without isostearic acid was used as Comparative Example 2.

[0089] (2) Evaluation items and evaluation methods The manufactured emulsified composition was subjected to the tests shown in Table 1. The results are shown in Table 1.

[0090] (2-1) Formulation stability Five evaluators specializing in cosmetic research and development evaluated the degree of syneresis (water separation) of the manufactured emulsified composition after it was left standing at room temperature for one week, using the following criteria on a three-point scale. ○...No water separation occurs at all. △...A small amount of water separation occurs. ×...A large amount of water separation occurs.

[0091] (2-2) Homogeneity of the formulation Regarding the appearance of the manufactured emulsified composition, five evaluators specializing in cosmetic research and development evaluated the uniformity of the formulation on a three-point scale based on the following criteria, considering factors such as the presence or absence of clumps and syneresis. ○...The appearance of the formulation is extremely uniform. △...The appearance of the formulation is almost uniform. ×...The formulation is extremely non-uniform.

[0092] [Table 1]

[0093] (2-3) Free evaluation by evaluators The comparative examples were subject to free evaluation by the evaluators. Based on the free evaluation, Comparative Example 1 was evaluated as having visible water separation on the surface. Furthermore, Comparative Example 2 was evaluated as having poor emulsification, with approximately 10% of the mixture undergoing syneresis. Furthermore, Comparative Example 3 was evaluated as having poor emulsification, with approximately 5% of the mixture undergoing syneresis.

[0094] (3) Results and Discussion The results of this study showed that even when the formulation contains a non-volatile oil with an IOB of 0.2 or higher, using a W / O type Pickering emulsion containing isostearic acid resulted in superior formulation stability and uniformity. [Industrial applicability]

[0095] This invention can be applied to W / O type Pickering emulsions that exhibit excellent formulation stability and uniformity.

Claims

1. A W / O type Pickering emulsion comprising an aqueous phase, an oil phase, and a hydrophobic powder, The aforementioned W / O type Pickering emulsion is Isostearic acid and, In addition to isostearic acid, a non-volatile oil agent with an IOB of 0.2 or higher is also included. Includes, The isostearic acid content is 1.2% by mass or more relative to the total amount of the W / O type Pickering emulsion. The mass ratio of isostearic acid to the non-volatile oil with an IOB of 0.2 or higher is within the range of 1:3 to 1:

10. The aforementioned non-volatile oils with an IOB of 0.2 or higher include propylene glycol meisostearate, diethylhexyl sebacate, 2-ethylhexyl paramethoxycinnamate, trimethylpropane tri-2-ethylhexanoate, di-2-ethylhexyl succinate, di(caprylic / capric acid)propylene glycol, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, tri(caprylic / capric acid)glyceryl, trimethylolpropane trioctanoate, glyceryl tricaprylate, ethylene glycol dioctanoate, glyceryl dimyristate, diethylene glycol dilaurate, pentaerythritol tetra-2-ethylhexanoate, glyceryl monostearate diacetate, propylene glycol monostearate, propylene glycol oleate, oleyl lactate, propylene glycol dicaproate, ethylene glycol monostearate, and dicap One or more selected from the group consisting of diethylene glycol phosphate, coconut oil fatty acid glyceryl, glyceryl dilaurate, glyceryl sesquioleate, ethylene glycol monooleate, coconut oil alcohol, lauryl alcohol, cetyl lactate, diethyl sebacate, methyl castor oil fatty acid, ethylene glycol palmitate, polyethylene glycol dilaurate, and tripropylene glycol dipivalate, ethylhexyl methoxycinnamate, isononyl isononanoate, octyldodecanol, diisostearyl malate, phytosteryl / octyldodecyl laurolyl glutamate, caprylic / capric triglyceride, 2-ethylhexyl hydroxystearate, propylene glycol dicaprylate, glyceryl tri-2-ethylhexanoate, octyldodecyl lactate, diisopropyl sebacate, and castor oil. W / O type Pickering emulsion.

2. The W / O type Pickering emulsion according to claim 1, wherein the mass ratio of isostearic acid to the hydrophobic powder is in the range of 1:0.3 to 1:

2.

3. The W / O type Pickering emulsion according to claim 1 or 2, wherein the non-volatile oil agent with an IOB of 0.2 or more is ethylhexyl methoxycinnamate.

4. The W / O type Pickering emulsion according to any one of claims 1 to 3, wherein the hydrophobic powder is silylated silica.

5. A W / O type Pickering emulsion according to any one of claims 1 to 4, characterized in that it contains 60% by mass or more of a volatile oil agent with respect to the total amount of oil agent contained in the oil phase.

6. The W / O type Pickering emulsion according to claim 5, wherein the volatile oil agent is selected from volatile silicone oil, volatile hydrocarbon oil, volatile ester oil, volatile natural animal and vegetable oil, and volatile fluorine oil.

7. A cosmetic composition comprising a W / O type Pickering emulsion as described in any one of claims 1 to 6.

8. The cosmetic composition according to claim 7, characterized in that it is a foundation or sunscreen.

9. A method for producing a W / O type Pickering emulsion comprising an aqueous phase, an oil phase, and a hydrophobic powder, The process comprises the steps of preparing an aqueous phase, preparing an oil phase, and mixing the aqueous phase and the oil phase to emulsify them. The oil phase comprises isostearic acid and In addition to isostearic acid, a non-volatile oil agent with an IOB of 0.2 or higher is also included. Contains hydrophobic powder, The isostearic acid content is 1.2% by mass or more relative to the total amount of the W / O type Pickering emulsion. The mass ratio of isostearic acid to the non-volatile oil with an IOB of 0.2 or higher is 1:3 to 1:

10. The aforementioned non-volatile oils with an IOB of 0.2 or higher include propylene glycol isostearate, diethylhexyl sebacate, 2-ethylhexyl paramethoxycinnamate, trimethylpropane tri-2-ethylhexanoate, di-2-ethylhexyl succinate, di(caprylic / capric acid)propylene glycol, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, tri(caprylic / capric acid)glyceryl, trimethylolpropane trioctanoate, glyceryl tricaprylate, ethylene glycol dioctanoate, glyceryl dimyristate, diethylene glycol dilaurate, pentaerythritol tetra-2-ethylhexanoate, glyceryl monostearate diacetate, propylene glycol monostearate, propylene glycol oleate, oleyl lactate, propylene glycol dicaproate, ethylene glycol monostearate, diethylene glycol dicaprate, di A method for producing a W / O type Pickering emulsion, characterized by using one or more selected from the group consisting of coconut oil fatty acid glyceryl, dilaurate glyceryl, sesquioleate glyceryl, monooleate ethylene glycol, coconut oil alcohol, lauryl alcohol, cetyl lactate, diethyl sebacate, castor oil fatty acid methyl, ethylene glycol palmitate, polyethylene glycol dilaurate, and tripropylene glycol dipivalate, ethylhexyl methoxycinnamate, isononyl isononanoate, octyldodecanol, diisostearyl malate, phytosteryl / octyldodecyl laurolyl glutamate, tri(caprylic / capric acid) glycerin, 2-ethylhexyl hydroxystearate, propylene glycol dicaprylate, glyceryl tri-2-ethylhexanoate, octyldodecyl lactate, diisopropyl sebacate, and castor oil.

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