Multi-layered cosmetics

Abstract

This invention provides a multi-layer cosmetic that can provide a cooling sensation and shine to the skin after application, has excellent cooling retention, and allows for easy mixing of the oil layer and water layer during use. [Solution] The following components (A), (B), (C), and (D): (A) Fatty acid ester having a pentaerythritol group (B) Volatile oils (C) Nonionic surfactants with an HLB value of 1 to 9 (D)Water A multi-layer cosmetic containing [specific ingredient].

Description

Technical Field

[0001] The present invention relates to a multi-layer cosmetic.

Background Art

[0002] Cosmetics that impart a cooling sensation during use and can sustain its effect have been proposed (for example, Patent Documents 1 and 2). Patent Document 1 describes a skin external preparation or cosmetic composition containing (A) a monoglyceride of a fatty acid having 6 to 12 carbon atoms and (B) a cooling agent. In Patent Document 1, the sustained cooling effect is achieved by defining the content mass ratio (A) / (B) of components (A) and (B) to be 0.4 to 3.

[0003] Patent Document 2 describes a cosmetic composition containing (A) sorbitan fatty acid and / or glyceryl isostearate, (B) polyoxyethylene hydrogenated castor oil having an average degree of polymerization of 60 to 100 of the polyoxyethylene chain, (C) one or more selected from dipropylene glycol, pentylene glycol, 1,3-butylene glycol, and propylene glycol, (D) menthol and / or a menthol derivative, and (E) water, which is described as having a sustained cooling sensation, no skin irritation, and excellent stability.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Typically, it is desirable for skin to exhibit sufficient luster after applying cosmetics. While it is ideal for cosmetics that provide a cooling sensation to also provide luster to the skin after application, a cosmetic that offers both excellent cooling duration and the desired luster to the skin after application has yet to be achieved. [Means for solving the problem]

[0006] The inventors of the present invention have diligently studied the components and effects of cosmetics that can impart a cooling sensation, and have found that by incorporating a specific oil having an erythritol group, the cooling sensation after application is significantly improved, and gloss is also imparted. Furthermore, they have found that a specific surfactant is effective in suppressing the precipitation of such oils at the interface between the oil layer and the water layer, thereby facilitating the mixing of the oil layer and the water layer.

[0007] The present invention comprises the following components (A), (B), (C), and (D): (A) Fatty acid ester having a pentaerythritol group (B) Volatile oils (C) Nonionic surfactants with an HLB value of 1 to 9 (D)Water This relates to a multi-layer cosmetic product containing [a specific ingredient / component]. [Effects of the Invention]

[0008] The multilayer cosmetic composition of this embodiment provides a cooling sensation and gloss to the skin after application, offers excellent cooling sensation retention, and allows for easy mixing of the two layers, the oil layer and the water layer, during use. [Modes for carrying out the invention]

[0009] The multilayer cosmetic composition of this embodiment contains a fatty acid ester having a pentaerythritol group as component (A). The fatty acid ester of component (A) can be selected from pentaerythritol fatty acid ester and dipentaerythritol fatty acid ester.

[0010] The fatty acids constituting component (A) may be either saturated or unsaturated fatty acids, but saturated fatty acids are preferred from the viewpoint of improving the duration of the cooling sensation and improving the stability of the two layers over time. Furthermore, either straight-chain or branched-chain fatty acids may be used, but straight-chain fatty acids are preferred from the viewpoint of improving the duration of the cooling sensation and improving the stability of the two layers over time. These fatty acids may also have hydroxyl groups.

[0011] Examples of such fatty acids include caproic acid, caprylic acid, 2-ethylhexanoic acid, isononanoic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, hydroxystearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, and melissic acid. Among the saturated fatty acids mentioned above, saturated fatty acids with 16 to 28 carbon atoms are preferred. Examples of such fatty acids include palmitic acid, stearic acid, isostearic acid, hydroxystearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, and montanic acid. Saturated fatty acids with 16 to 22 carbon atoms are more preferred, for example, palmitic acid, stearic acid, isostearic acid, hydroxystearic acid, arachidic acid, and behenic acid.

[0012] The alcohols constituting component (A) are pentaerythritol and dipentaerythritol, and among these, dipentaerythritol is preferred from the viewpoint of improving the duration of the cooling sensation and improving the long-term stability of the two layers. Component (A) includes, for example, pentaerythritol fatty acid esters such as (behenic acid / polyhydroxystearic acid) pentaerythrityl, and for example, dipentaerythritol fatty acid esters such as dipentaerythrityl hexaoxystearate, dipentaerythrityl tripolyhydroxystearate, dipentaerythrityl pentaisostearate, and dipentaerythrityl tetraisostearate.

[0013] As for component (A), from the viewpoint of improving the duration of the cooling sensation and improving the long-term stability of the two layers, it is preferable to include dipentaerythritol fatty acid ester, more preferably one or more selected from dipentaerythrityl hexaoxystearate, dipentaerythrityl tripolyhydroxystearate, dipentaerythrityl pentaisostearate, and dipentaerythrityl tetraisostearate, even more preferably one or more selected from dipentaerythrityl hexaoxystearate, dipentaerythrityl tripolyhydroxystearate, and dipentaerythrityl pentaisostearate, even more preferably one or more selected from dipentaerythrityl hexaoxystearate and dipentaerythrityl tripolyhydroxystearate, and especially preferably dipentaerythrityl hexaoxystearate.

[0014] Commercially available products such as Cosmol 168M (manufactured by Nisshin Oillio Group Co., Ltd.) can be used as dipentaerythrityl hexaoxystearate, Saracos WO-6 (manufactured by Nisshin Oillio Group Co., Ltd.) as dipentaerythrityl tripolyhydroxystearate, Saracos DP-518N (manufactured by Nisshin Oillio Group Co., Ltd.) as dipentaerythrityl pentaisostearate, and Saracos 5418V (manufactured by Nisshin Oillio Group Co., Ltd.) as dipentaerythrityl tetraisostearate can be used.

[0015] Component (A) may be used alone or in combination of two or more. From the viewpoint of improving the duration of the cooling sensation and improving the luster of the skin after application, the content of component (A) in the multilayer cosmetic composition is preferably 0.1% by mass or more, more preferably 0.15% by mass or more, and even more preferably 0.25% by mass or more. Furthermore, from the viewpoint of improving the long-term stability of the two layers, the content of component (A) is preferably 1% by mass or less, more preferably 0.6% by mass or less, and even more preferably 0.35% by mass or less. The content of component (A) in the multilayer cosmetic composition is preferably 0.1 to 1% by mass, more preferably 0.15 to 0.6% by mass, and even more preferably 0.25 to 0.35% by mass.

[0016] The volatile oil of component (B) is an oil having a flash point of 35 to 160°C. The volatile oil can be selected from volatile silicone oils and volatile hydrocarbon oils. Examples of volatile silicone oils include linear dimethylpolysiloxanes such as dimethylpolysiloxane (1 cs), dimethylpolysiloxane (1.5 cs), and dimethylpolysiloxane (2 cs); branched dimethylpolysiloxanes such as tris(trimethylsiloxy)methylsilane; and cyclic dimethylsiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane.

[0017] Of these, it is preferable to include one or more selected from linear dimethylpolysiloxane and branched dimethylpolysiloxane, more preferably one or more selected from branched dimethylpolysiloxane, and even more preferably tris(trimethylsiloxy)methylsilane.

[0018] Examples of the volatile hydrocarbon oil include paraffinic hydrocarbon oils such as n-decane, n-undecane, and n-dodecane; isoparaffinic hydrocarbon oils such as isodecane, isododecane, and hydrogenated polyisobutene; and cyclic paraffin hydrocarbon oils such as cyclodecane and cyclododecane. Among these, hydrocarbon oils having 8 to 16 carbon atoms are preferable, hydrocarbon oils having 10 to 16 carbon atoms are more preferable, and hydrocarbon oils having 12 carbon atoms are even more preferable.

[0019] Component (B) may be used alone or in combination of two or more. From the viewpoint of improving the cold sensation persistence, the content of component (B) in the multi-layer cosmetic is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.8% by mass or more, and still more preferably 1.5% by mass or more. Further, from the viewpoint of improving the stability over time of the two layers, the content of component (B) is preferably 12% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less, and still more preferably 2.5% by mass or less. The content of component (B) in the multi-layer cosmetic is preferably 0.1 to 12% by mass, more preferably 0.5 to 7% by mass, even more preferably 0.8 to 5% by mass, and still more preferably 1.5 to 2.5% by mass.

[0020] From the viewpoints of improving the cold sensation persistence, improving the gloss of the skin after application, improving the moist feeling of the skin after application, improving the ease of mixing of the two layers, and improving the stability over time of the two layers, the mass ratio (A) / (B) of component (A) and component (B) is preferably 0.01 or more, more preferably 0.03 or more, even more preferably 0.06 or more, still more preferably 0.08 or more, and even further preferably 0.12 or more.

[0021] Also, from the viewpoints of improving the cold feeling persistence, improving the gloss of the skin after application, improving the moist feeling of the skin after application, improving the ease of mixing of the two layers, and improving the stability over time of the two layers, the mass ratio (A) / (B) is preferably 10 or less, more preferably 3 or less, still more preferably 1 or less, even more preferably 0.25 or less, and particularly more preferably 0.18 or less. The mass ratio (A) / (B) is preferably 0.01 to 10, more preferably 0.03 to 3, still more preferably 0.06 to 1, even more preferably 0.08 to 0.25, and particularly more preferably 0.12 to 0.18.

[0022] Component (C) is a nonionic surfactant having an HLB value of 1 to 9. Specifically, lipophilic nonionic surfactants can be mentioned. As the lipophilic nonionic surfactant, from the viewpoints of improving the cold feeling persistence and improving the stability over time of the two layers, the HLB value is preferably 1 to 8, more preferably 2 to 7, and still more preferably 3 to 6.

[0023] Here, the HLB value (Hydrophilic-Lipophilic Balance) indicates the molecular weight of the hydrophilic group portion in the total molecular weight of the surfactant, and is obtained by the Griffin's formula. Also, when composed of two or more nonionic surfactants, the HLB value of the mixed surfactant is determined as follows. The HLB value of the mixed surfactant is the weighted average obtained by adding the HLB values of each nonionic surfactant based on their blending ratios. Mixed HLB value = Σ(HLBx × Wx) / ΣWx HLBx indicates the HLB value of nonionic surfactant X. Wx indicates the mass (g) of nonionic surfactant X having the value of HLBx.

[0024] Examples of lipophilic nonionic surfactants include glycerin fatty acid esters such as glyceryl stearate, propylene glycol fatty acid esters, sorbitan fatty acid esters such as sorbitan monoisostearate, sorbitan monooleate, sorbitan sesquistearate, and sorbitan sesquioleate, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene hydrogenated castor oil fatty acid esters, polyethylene glycol fatty acid esters, alkyl glyceryl ethers, alkyl polyglyceryl ethers, polyoxyethylene alkyl ether fatty acid esters, polyoxyethylene alkylamines, and silicone-based surfactants such as polyether-modified silicones such as polyoxyethylene methylpolysiloxane copolymers and poly(oxyethylene oxypropylene) methylpolysiloxane copolymers, alkyl-modified polyether-modified silicones, and alkyl chain-comodified polyether-modified silicones.

[0025] Of these, from the viewpoint of improving the duration of the cooling sensation and improving the long-term stability of the two layers, it is preferable to include one or more selected from sorbitan fatty acid esters, silicone-based surfactants, and glycerin fatty acid esters; more preferably to include one or more selected from sorbitan fatty acid esters and polyether-modified silicones; even more preferably to include one or more selected from sorbitan monoisostearate, sorbitan monooleate, sorbitan sesquistearate, and polyether-modified silicones; even more preferably to include one or more selected from sorbitan monoisostearate and polyoxyethylene-methylpolysiloxane copolymers; and especially preferably to include sorbitan monoisostearate.

[0026] Lipophilic nonionic surfactants can be commercially available. For example, sorbitan monoisostearate can be Span 120 (HLB value 4.7) (manufactured by Croda Japan Co., Ltd.), polyoxyethylene methylpolysiloxane copolymers can be KF-6015 (HLB value 4.5), KF-6017 (HLB value 4.5), KF-6028 (HLB value 4) (all manufactured by Shin-Etsu Chemical Co., Ltd.), DOWSIL SH3775M (HLB value 5) (manufactured by Dow-Toray Co., Ltd.), and poly(oxyethylene oxypropylene) methylpolysiloxane copolymers can be KF-6012 (HLB value 7) (manufactured by Shin-Etsu Chemical Co., Ltd.), DOWSIL BY 22-008M (HLB value 2), DOWSIL ES-5226 DM Formulation. Examples of alkyl-modified polyether-modified silicones include Aid (HLB value 2) (manufactured by Dow-Toray), KF-6038 (HLB value 3) (manufactured by Shin-Etsu Chemical Co., Ltd.), ABILEM 90 (HLB value 5) (manufactured by Evonik Japan), and glycerin fatty acid esters include NIKKOL MGS BSEV (HLB value 8) (Nikko Chemicals Co., Ltd.).

[0027] Component (C) may be used alone or in combination of two or more. From the viewpoint of improving the duration of the cooling sensation, improving the luster of the skin after application, and improving the ease of mixing the two layers, the content of component (C) in the multilayer cosmetic composition is preferably 0.001% by mass or more, more preferably 0.003% by mass or more, and even more preferably 0.005% by mass or more. Furthermore, from the viewpoint of improving the moisturizing effect on the skin after application and improving the long-term stability of the two layers, the content of component (C) is preferably 0.02% by mass or less, more preferably 0.015% by mass or less, and even more preferably 0.007% by mass or less. The content of component (C) in the multilayer cosmetic composition is preferably 0.001 to 0.02% by mass, more preferably 0.003 to 0.015% by mass, and even more preferably 0.005 to 0.007% by mass.

[0028] From the viewpoint of improving the duration of the cooling sensation, improving the luster of the skin after application, improving the moisturizing effect of the skin after application, improving the ease of mixing the two layers, and improving the long-term stability of the two layers, the mass ratio (A) / (C) of component (A) to component (C) is preferably 1 or more, more preferably 10 or more, even more preferably 25 or more, and even more preferably 40 or more. Furthermore, from the viewpoint of improving the duration of the cooling sensation, improving the luster of the skin after application, improving the moisturizing effect of the skin after application, improving the ease of mixing the two layers, and improving the long-term stability of the two layers, the mass ratio (A) / (C) is preferably 300 or less, more preferably 100 or less, even more preferably 71 or less, and even more preferably 59 or less. The mass ratio (A) / (C) is preferably 1 to 300, more preferably 10 to 100, even more preferably 25 to 71, and even more preferably 40 to 59.

[0029] The components (A), (B), and (C) described above constitute the oil layer. Preferably, the oil layer further contains an oil agent other than component (B) that is liquid at 25°C, and a cooling agent. Examples of oils that are liquid at 25°C other than component (B) include hydrocarbon oils, ester oils, ether oils, silicone oils, higher alcohols, and higher fatty acids. Examples of ester oils include monoester oils, diester oils, and triester oils. Specifically, examples of monoester oils include cetyl 2-ethylhexanoate, cetyl octanoate, isononyl isononanoate, isotridecyl isononanoate, isopropyl myristate, octyldodecyl myristate, isopropyl palmitate, octyl methoxycinnamate, and alkyl benzoates (C12-C15).

[0030] As for the monoester oil, from the viewpoint of improving the duration of the cooling sensation and improving the luster of the skin after application, it is preferable to include one or more selected from isononyl isononanoate, isotridecyl isononanoate, and octyldodecyl myristate, and more preferably to include one or more selected from octyldodecyl myristate and isotridecyl isononanoate. Examples of diester oils include propylene glycol dicaprylate and neopentyl glycol dicaprate. From the viewpoint of improving the duration of the cooling sensation and improving the luster of the skin after application, it is preferable that the diester oil contains one or more selected from propylene glycol dicaprylate and neopentyl glycol dicaprate, and it is more preferable that it contains neopentyl glycol dicaprate.

[0031] Examples of triester oils include, specifically, tri(caprylic / capric acid) glyceryl, glyceryl tri-2-ethylhexanoate, and vegetable oils such as olive oil, macadamia nut oil, meadowfoam oil, castor oil, safflower oil, sunflower oil, avocado oil, canola oil, apricot kernel oil, rice germ oil, and rice bran oil. As for the triester oil, from the viewpoint of improving the duration of the cooling sensation and improving the luster of the skin after application, it is preferable to include one or more selected from tri(caprylic / capric acid) glyceryl tri-2-ethylhexanoate and vegetable oil, more preferably to include one or more selected from tri(caprylic / capric acid) glyceryl tri-2-ethylhexanoate, and even more preferably to include tri(caprylic / capric acid) glyceryl.

[0032] As for the ester oil, it is preferable to include one or more selected from diester oils and triester oils, and more preferably triester oil, from the viewpoint of improving the duration of the cooling sensation and improving the luster of the skin after application. Examples of silicone oils include non-volatile linear dimethylpolysiloxanes such as dimethylpolysiloxane (6cs) and dimethylpolysiloxane (10cs), and methylphenylpolysiloxanes such as diphenylsiloxyphenyl trimethicone. As for the silicone oil, from the viewpoint of improving the duration of the cooling sensation and improving the luster of the skin after application, it is preferable to include one or more selected from non-volatile linear dimethylpolysiloxane and methylphenylpolysiloxane, more preferably to include one or more selected from dimethylpolysiloxane (6cs) and methylphenylpolysiloxane, and even more preferably to include methylphenylpolysiloxane.

[0033] Examples of higher alcohols include isocetyl alcohol, isostearyl alcohol, 2-octyldodecanol, and oleyl alcohol. From the viewpoint of improving the luster of the skin after application, it is preferable to include 2-octyldodecanol. As for the liquid oil at 25°C other than component (B), from the viewpoint of improving the duration of the cooling sensation and improving the luster of the skin after application, it is preferable to include one or more selected from ester oils, silicone oils, and higher alcohols, more preferably one or more selected from ester oils, even more preferably one or more selected from diester oils and triester oils, even more preferably one or more selected from triester oils, and especially preferably tri(caprylic / capric acid)glyceride.

[0034] As cooling agents, L-menthol and L-menthyl lactate are preferably used. Cooling agents may be used individually or in combination of two or more. From the viewpoint of improving the duration of the cooling sensation, the content of cooling agents in the multilayer cosmetic composition is preferably 0.01% by mass or more, more preferably 0.015% by mass or more, and even more preferably 0.02% by mass or more. Also, from the viewpoint of avoiding irritation, the content of cooling agents is preferably 0.8% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.4% by mass or less. The content of cooling agent C) in the multilayer cosmetic composition is preferably 0.01 to 0.8% by mass, more preferably 0.015 to 0.5% by mass, and even more preferably 0.02 to 0.4% by mass.

[0035] From the viewpoint of improving the luster of the skin after application, the oil layer content in a multilayer cosmetic composition is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 25% by mass or more. Furthermore, from the viewpoint of improving the duration of the cooling sensation, the oil layer content in a multilayer cosmetic composition is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 35% by mass or less. The oil layer content in a multilayer cosmetic composition is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and even more preferably 25 to 35% by mass.

[0036] Component (D), water, contributes to the cooling sensation, and ion-exchanged water or the like can be used. From the viewpoint of improving the duration of the cooling sensation, the water content in the multilayer cosmetic composition is preferably 35% by mass or more, more preferably 40% by mass or more, and even more preferably 45% by mass or more. Furthermore, from the viewpoint of improving the luster of the skin after application, the water content in the multilayer cosmetic composition is preferably 65% ​​by mass or less, more preferably 60% by mass or less, and even more preferably 55% by mass or less. The water content in the multilayer cosmetic composition is preferably 35 to 65% by mass, more preferably 40 to 60% by mass, and even more preferably 45 to 55% by mass.

[0037] Preferably, the aqueous layer containing component (D) further contains a sugar alcohol and a pH adjuster. Sugar alcohols can improve the duration of the cooling sensation, and pH adjusters can improve skin compatibility.

[0038] Sugar alcohols are obtained by reducing the reducing groups (aldehyde groups and ketone groups) of sugars that have reducing groups to form alcohol groups. Examples of sugar alcohols include xylitol, lactitol, paranititol, sorbitol, maltitol, mannitol, erythritol, trehalose, glucosyltrehalose, and polyoxyalkylene alkyl glucosides such as polyoxyethylene methyl glucoside and polyoxypropylene methyl glucoside. Of these, from the viewpoint of improving the luster of the skin after application and improving the feeling of moisture in the skin, it is preferable to include one or more selected from xylitol, sorbitol, maltitol, and trehalose, and more preferably to include one or more selected from xylitol and sorbitol.

[0039] Sugar alcohols may be used alone or in combination of two or more types. From the viewpoint of improving the duration of the cooling sensation, the sugar alcohol content in the multilayer cosmetic composition is preferably 1% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2% by mass or more. Also from the viewpoint of improving the duration of the cooling sensation, the sugar alcohol content is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less. The sugar alcohol content in the multilayer cosmetic composition is preferably 1 to 10% by mass, more preferably 1.5 to 7% by mass, and even more preferably 2 to 5% by mass.

[0040] Any pH adjuster commonly used in cosmetics may be used, with inorganic acids and their salts, organic acids having 6 or fewer carbon atoms and their salts being preferred, and organic acids having 6 or fewer carbon atoms and their salts being more preferred. The inorganic acid preferably includes one or more selected from, for example, hydrochloric acid, nitric acid, nitrite, sulfuric acid, sulfurous acid, phosphoric acid, phosphonic acid, phosphinic acid, and salts thereof; more preferably includes one or more selected from hydrochloric acid, phosphoric acid, and salts thereof; and even more preferably includes hydrochloric acid and salts thereof.

[0041] Furthermore, as organic acids having 6 or fewer carbon atoms and their salts, water-soluble organic acids and their salts are preferred, such as fatty acids, hydroxy acids, dicarboxylic acids, acidic amino acids, and their salts, each having 1 to 6 carbon atoms. Of these, it is preferable to include one or more selected from malic acid, lactic acid, citric acid, succinic acid, acetic acid, tartaric acid, glutamic acid, aspartic acid, adipic acid, and their salts; more preferably to include one or more selected from malic acid, lactic acid, citric acid, succinic acid, and their salts; and even more preferably to include one or more selected from citric acid and its salts.

[0042] The pH adjusting agent preferably contains both an acid and its salts. When both an acid and its salts are present, the mass ratio of the acid content to the salt content (acid) / (salt) is preferably 1 to 5, more preferably 1 to 3, even more preferably 1 to 2, and even more preferably 1 to 1.5.

[0043] pH adjusters may be used alone or in combination of two or more types. From the viewpoint of skin compatibility, the content of pH adjusters in multilayer cosmetics is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more. Also, from the viewpoint of suppressing stickiness, the content of pH adjusters is preferably 0.5% by mass or less, more preferably 0.4% by mass or less, and even more preferably 0.3% by mass or less. The content of pH adjusters in multilayer cosmetics is preferably 0.01 to 0.5% by mass, more preferably 0.05 to 0.4% by mass, and even more preferably 0.1 to 0.3% by mass.

[0044] From the viewpoint of improving the duration of the cooling sensation, the water layer content in the multilayer cosmetic composition is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 65% ​​by mass or more. Furthermore, from the viewpoint of improving the luster of the skin after application, the water layer content in the multilayer cosmetic composition is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 75% by mass or less. The water layer content in the multilayer cosmetic composition is preferably 50 to 90% by mass, more preferably 55 to 85% by mass, and even more preferably 65 to 75% by mass.

[0045] From the viewpoint of improving the luster of the skin after application, the ratio of the water layer to the oil layer (water layer / oil layer) in a multilayer cosmetic composition is preferably 1 or more, more preferably 1.2 or more, and even more preferably 1.5 or more. Also, from the viewpoint of avoiding insufficient cooling sensation, the ratio of the water layer to the oil layer (water layer / oil layer) is preferably 5 or less, more preferably 4.5 or less, and even more preferably 3 or less. The ratio of the water layer to the oil layer (water layer / oil layer) in a multilayer cosmetic composition is preferably 1 to 5, more preferably 1.2 to 4.5, and even more preferably 1.5 to 3.

[0046] The multilayer cosmetic composition of this embodiment may contain, in addition to the above-mentioned components, other components commonly used in multilayer cosmetic compositions, to the extent that they do not impair the effects of this embodiment. For example, it may contain polyols such as dipropylene glycol, 1,3-butylene glycol, and glycerin, ethanol, surfactants other than component (C), oils that are solid at 25°C, water-soluble thickeners, preservatives, and the like.

[0047] The multilayer cosmetic composition of this embodiment can be manufactured, for example, by preparing an oil layer mixture and an aqueous layer mixture separately and mixing them. The oil layer mixture can be prepared by heating and stirring components (A), (B), (C) and other oily components at 70-80°C and confirming that they dissolve. The aqueous layer mixture can be prepared by heating and stirring component (D) and other aqueous components at 40-50°C and confirming that they dissolve. The multilayer cosmetic composition of this embodiment is obtained by filling a container with an oil layer mixture and an aqueous layer mixture at 20-30°C.

[0048] From the viewpoint of improving stability, the multilayer cosmetic composition of this embodiment preferably has a pH in the range of 3 to 7, more preferably 3.5 to 6, and even more preferably 4 to 5. The pH of the topical composition is measured at 25°C using a pH meter (HORIBA F-72 benchtop pH meter).

[0049] The multilayer cosmetic of this embodiment can be mixed by shaking the container to combine the oil layer and the water layer, then an appropriate amount can be taken and applied directly to the skin of the face, body, hands, feet, etc. Alternatively, it may be applied to the skin by soaking it in a fabric or non-woven material. The multilayer cosmetic of this embodiment allows for easy mixing of the oil layer and the water layer, and when applied to the skin, it provides a cooling sensation and shine, and maintains that cooling sensation. Moreover, the multilayer cosmetic of this embodiment has excellent long-term stability of the two layers, and can also provide a moisturizing sensation to the skin after application.

[0050] Although preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the embodiments described above. Various modifications or improvements can be made to each of the above embodiments. [Examples]

[0051] Next, embodiments of the present invention will be described, but this will not limit the present invention.

[0052] Multilayer cosmetic compositions of the examples and comparative examples were prepared with the compositions (mass%) shown in Table 1 below. In preparation, an oily component containing components (A), (B), and (C) was first mixed at 80°C using a propeller stirrer to prepare an oil layer mixture. Meanwhile, an aqueous component containing component (D) was mixed at 40°C using a propeller stirrer to prepare an aqueous layer mixture. Each multilayer cosmetic composition was obtained by filling containers with the oil and aqueous layer mixtures at 25°C.

[0053] The obtained multilayer cosmetic composition was examined for its cooling effect duration (temperature change value), gloss, skin moisture level after application, ease of mixing of the two layers, and long-term stability of the two layers. The measurement methods for each are as follows.

[0054] (1) Cooling effect duration (temperature change value) A multi-layer cosmetic was applied to artificial leather, and the duration of the cooling sensation was evaluated based on the temperature change of the artificial leather after application. The temperature change was measured using the following procedure (a) to (d). (a) 10 g of multilayer cosmetic was placed in a container (Mighty Vial No. 4, manufactured by Maruel Co., Ltd.) and left to stand in a constant temperature room at 25°C for 3 hours together with artificial leather (model number Supplere, manufactured by Ideatex Japan Co., Ltd.). (b) After 3 hours, the surface temperature of the artificial leather "before application" of the multi-layer cosmetic was measured three times using an infrared thermometer (model IR-805, manufactured by Shenzhen Flus Technology Co., Ltd.), and the average value was calculated. This was defined as the "temperature of the artificial leather before application (T0)". (c) Next, the container holding the multilayer cosmetic is shaken up and down (shaking width of 15 cm, shaking speed of 5 times / 5 seconds) to mix uniformly, and then 1.25 μL / cm of the multilayer cosmetic is dispensed from the container. 2 Take it out and place it on the artificial leather, 3 x 3 cm 2 The material was applied to the area. Two minutes after application, the surface temperature of the area where the multi-layer cosmetic was applied was measured in the same manner as in procedure (b). This was defined as "temperature of the artificial leather after application (T1)". (d) The "temperature change value" was calculated from the following formula. "Temperature change value" = T1 - T0 The temperature change value is a negative number, preferably with an absolute value of 1.5°C or more, more preferably 2°C or more, and even more preferably 2.5°C or more.

[0055] (2) Shine In a 25°C constant temperature room, the container holding the multilayer cosmetic was shaken up and down (shaking amplitude of 15 cm, shaking rate of 5 times / 5 seconds). After homogeneous mixing, the concentration was 1.25 μL / cm³. 2 The multi-layered cosmetic was taken from the container and placed on artificial leather (model number Sapure: manufactured by Ideatex Japan) in a 2 x 8 cm size.2 The coating was applied to the area over a period of 1 minute. After drying for 10 minutes, the luminance value (maximum reflected light intensity) was measured using a gloss meter (SAMBA HAIR SYSTEM (THALES)). Three measurements were taken, and the average value was calculated. The luminance value is preferably 15.2 or higher, more preferably 15.5 or higher, and even more preferably 16 or higher.

[0056] (3) Moisture feeling of the skin after application The container holding the multilayer cosmetic was shaken up and down (shaking amplitude of 15 cm, shaking speed of 5 times / 5 seconds) to ensure uniform mixing. After that, 0.2 g of the multilayer cosmetic was taken from the container and applied to the faces of three professional evaluators. After 30 minutes, the evaluators touched their skin with their fingers and evaluated the moisturizing effect according to the following criteria. The results are shown as the total score of the three evaluators. 5: I can clearly feel the moisturizing effect. 4: I feel a sense of moisture. 3: I feel a slight moisturizing effect. 2: I don't feel much moisture. 1: I clearly don't feel any moisturizing effect.

[0057] (4) Ease of mixing the two layers In a constant temperature room at 25°C, the multilayer cosmetic product immediately after manufacturing was shaken up and down (shaking amplitude of 15 cm, shaking speed of 1 time / 1 second), and the dispersion state immediately after each shake was visually observed. If a uniform dispersion state was not confirmed, shaking was immediately performed and the evaluation was continued. The ease of mixing the two layers was evaluated based on the number of shakes required to confirm a uniform dispersion state. The number of shakes required to confirm a uniform dispersion state is acceptable if it is 10 times or less, and preferably 5 times or less.

[0058] (5) Stability over time of the two layers Immediately after manufacturing, multilayer cosmetic materials were left to stand in a constant temperature bath at 25°C. After 24 hours, the precipitation of foreign matter at the layer interface (oil layer-water layer) was visually observed and evaluated according to the following criteria. Foreign matter was defined as a gel-like substance clearly different from the liquid, or a semi-cloudy substance. If foreign matter was found, the material was shaken up and down (shaking amplitude of 15 cm, shaking rate of 5 times / 5 seconds) and then visually observed. 3: No foreign matter was found at the layer interface. 2: Although foreign matter is present at the layer interface, it is uniformly dispersed by shaking. 1: Foreign matter is present at the layer interface and does not disperse uniformly even when shaken.

[0059] The results obtained, along with the composition, are summarized in Table 1 below.

[0060] [Table 1]

[0061] *1: Cosmoll 168M: Manufactured by Nisshin Oillio Group Co., Ltd. *2: Saracos WO-6: Manufactured by Nisshin Oillio Group Co., Ltd. *3: TMF-1.5: Manufactured by Shin-Etsu Chemical Co., Ltd. *4: Span 120: Manufactured by Croda Japan Co., Ltd. *5: Coconard MT: Manufactured by Kao Corporation

[0062] The multilayer cosmetic composition of the example contains all of components (A) to (D), providing a cooling sensation and gloss, excellent cooling retention, and easy mixing. Moreover, it provides sufficient moisture after application, and the two layers exhibit good stability over time. As shown in Comparative Examples 1 and 2, the absence of component (A) or component (B) results in inferior cooling effect. Furthermore, Comparative Example 3 shows that the absence of component (C) significantly degrades the ease of mixing.

[0063] Tables 2-4 below show examples of two-layer oil serum formulations. The ingredient amounts in each table are in mass percent.

[0064] [Table 2]

[0065] [Table 3]

[0066] [Table 4]

[0067] *6: Saracos DP-518N: Manufactured by Nisshin Oillio Group Co., Ltd. *7: Oitano G-JP: Manufactured by BASF Japan *8: DOWSIL FZ-209: Manufactured by Dow Toray Corporation *9: KF-96A-6CS: Manufactured by Shin-Etsu Chemical Co., Ltd. *10: NEOSOLUE-AQUA: Manufactured by Nippon Seika Co., Ltd. *11: NEOSOLUE-AQULIO: Manufactured by Nippon Seika Co., Ltd. *12: KF-96L-2CS: Manufactured by Shin-Etsu Chemical Co., Ltd.

[0068] The multilayer cosmetic composition of the present invention, if it contains all of components (A) to (D), provides a cooling sensation and shine even when an optional component is added to form a two-layer oil serum, exhibits excellent cooling retention, and is easy to mix. Moreover, it provides sufficient moisture after application, and the two layers exhibit good stability over time.

Claims

1. The following components (A), (B), (C), and (D): (A) Fatty acid ester having a pentaerythritol group (B) Volatile oils (C) Nonionic surfactants with an HLB value of 1 to 9 (D) Water A multi-layer cosmetic containing [specific ingredient].

2. The multilayer cosmetic composition according to claim 1, wherein component (A) comprises one or more selected from dipentaerythrityl hexaoxystearate, dipentaerythrityl pentaisostearate, and dipentaerythrityl tripolyhydroxystearate.

3. The multilayer cosmetic composition according to claim 1 or 2, wherein the component (B) comprises a volatile silicone oil.

4. The multilayer cosmetic composition according to claim 1 or 2, wherein the mass ratio (water layer) / (oil layer) of the oil layer containing the components (A), (B), and (C) to the water layer containing the component (D) is 1 to 5.

5. The multilayer cosmetic composition according to claim 1 or 2, wherein the mass ratio ((A) / (B)) of component (A) to component (B) is 0.01 to 10.

6. The multilayer cosmetic composition according to claim 1 or 2, wherein the mass ratio ((A) / (C)) of component (A) to component (C) is 1 to 300.

7. The multilayer cosmetic composition according to claim 1 or 2, wherein the content of component (C) is 0.001 to 0.02% by mass.

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