Oil-in-water emulsion cosmetics

Abstract

To provide an oil-in-water emulsion cosmetic with high moisturizing effect and viscosity stability. [Solution] An oil-in-water emulsion cosmetic comprising (A) a hydrophilic nonionic surfactant, (B) a higher aliphatic alcohol having 12 or more carbon atoms, (C) a polyethylene glycol difatty acid ester with a polymerization number of 20 or less of polyoxyethylene glycol, (D) an oil, and (E) water.

Description

Technical Field

[0001] The present invention provides an oil-in-water emulsion cosmetic having a high moisturizing effect and good viscosity stability.

Background Art

[0002] Conventionally, for the purpose of maintaining the emulsion stability of skin external preparations such as cosmetics, quasi-drugs, and pharmaceuticals, α-gel-containing skin external preparations using α-gel formed by higher aliphatic alcohols, higher fatty acids, and hydrophilic surfactants have been used (Patent Document 1). Such α-gel has a high viscosity and has an effect of improving the stability of skin external preparations, but higher alcohols and higher fatty acids may precipitate as crystals over time, and further improvement has been demanded. In addition, the viscosity may increase over time, and improvement by using a two-chain cationic surfactant or the like as a viscosity increasing inhibitor has also been studied. However, in the study by the present inventors, there was room for further improvement.

[0003] In addition, in order to achieve a high moisturizing effect in an oil-in-water emulsion cosmetic, the blending of water-soluble moisturizing agents such as glycerin and amino acids and oil components has been studied. Such moisturizing agents and oil components play the role of sebum lost by washing or the like, and impart to the skin external preparation a function as an emollient for keeping the skin soft and a moisturizing function substituting for NMF (Natural Moisture Rising Factor). However, when a large amount of such oil components and moisturizing agents are blended, there is a tendency to cause greasiness and stickiness, and improvement has also been demanded in this regard.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] According to the present invention, an oil-in-water emulsion cosmetic having a high moisturizing effect and viscosity stability is provided.

[0006] The present invention provides the following: [1] (A) Hydrophilic nonionic surfactant, (B) Higher aliphatic alcohols with 12 or more carbon atoms, (C) Polyethylene glycol difatty acid ester with a polymerization number of 20 or less, (D) Oils and (E)Water An oil-in-water emulsion cosmetic containing [the specified ingredient]. [2] The cosmetic composition according to [1], wherein component (A) is selected from the group consisting of polyoxyethylene alkyl ether, polyglycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene lanolin / lanolin alcohol / beeswax derivative, polyoxyethylene castor oil / hydrogenated castor oil, polyoxyethylene sterol / hydrogenated sterol, polyethylene glycol fatty acid ester, and polyoxyethylene glyceryl isostearate. [3] (A) A cosmetic composition according to [1] or [2], wherein component (A) is selected from the group consisting of alkyl ether surfactants having a linear alkyl group with 16 or more carbon atoms, and alkyl ester surfactants. [4] (B) A cosmetic composition according to any one of [1] to [3], wherein the hydrocarbon chain of component (B) has a linear structure. [5] (B) A cosmetic composition according to any one of [1] to [4], wherein the component is a mixture of two or more higher aliphatic alcohols. [6] (C) A cosmetic composition according to any one of [1] to [5], wherein the hydrocarbon chain derived from fatty acids constituting component (C) has a linear structure. [7] A cosmetic composition according to any one of [1] to [6], wherein the content of component (A), based on the total mass of the cosmetic composition, is 0.2 to 1.4% by weight. [8] The cosmetic composition described in any of [1] to [7], wherein the content of component (B), based on the total mass of the cosmetic composition, is three times or more the content of component (A). [9] When the number of moles of component (A) and component (B) contained in the cosmetic composition are calculated based on their number-average molecular weights, let Ma and Mc be respectively, the ratio of Mc to Ma, Mc / Ma, is given by the following relationship: 0.1 <Mc / Ma<0.5 A cosmetic product that satisfies any of the following conditions, as described in [1] to [8].

[0007] According to the present invention, a cosmetic composition is provided that exhibits minimal viscosity fluctuations even during long-term storage, high moisturizing properties during use, and sustains its moisturizing effect over a long period of time. Specific description of the invention

[0008] The oil-in-water emulsion cosmetic composition according to the present invention (hereinafter sometimes simply referred to as "cosmetic composition") is (A) Hydrophilic nonionic surfactant, (B) Higher aliphatic alcohols, (C) Polyethylene glycol difatty acid ester, (D) Oils and (E)Water It consists of the following. Each of these components, as well as any additional components that may be added, are described below.

[0009] (A) Hydrophilic nonionic surfactant The cosmetic composition according to the present invention comprises a hydrophilic nonionic surfactant (hereinafter sometimes referred to as component (A)). Component (A) forms an interfacial film of oil droplets in the emulsified cosmetic composition and is hydrophilic. Since component (A) is hydrophilic, its HLB value is preferably 12 to 20, and more preferably 15 to 20. Here, HLB is a value that generally indicates the affinity of a surfactant for water and oil, and is a parameter known as the hydrophilic-lipophilic balance, which can be easily determined by known calculation methods such as the Griffin method.

[0010] The preferred component (A) is selected from the group consisting of polyoxyethylene alkyl ethers, polyglycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene lanolin / lanolin alcohol / beeswax derivatives, polyoxyethylene castor oil / hydrogenated castor oil, polyoxyethylene sterols / hydrogenated sterols, polyethylene glycol fatty acid esters, and polyoxyethylene glyceryl isostearate.

[0011] Furthermore, component (A) is preferably selected from the group consisting of alkyl ether surfactants having a linear alkyl group with 16 or more carbon atoms, and alkyl ester surfactants.

[0012] In the present invention, polyoxyethylene alkyl ether is more preferably used as component (A). Examples of polyoxyethylene alkyl ethers include polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene behenyl ether, and polyoxyethylene stearyl ether, with polyoxyethylene behenyl ether and polyoxyethylene stearyl ether being the most preferred. Specifically, examples include POE(15) cetyl ether (HLB 15.5), POE(20) cetyl ether (HLB 17.0), POE(23) cetyl ether (HLB 18.0), POE(20) stearyl ether (HLB 18.0), POE(21) ​​stearyl ether (HLB value 18.0), POE(15) oleyl ether (HLB 16.0), POE(20) oleyl ether (HLB 17.0), POE(50) oleyl ether (HLB 18.0), POE(20) behenyl ether (HLB 16.5), POE(30) behenyl ether (HLB 18.0), and POE(10)(C12-15) alkyl ether (HLB 15.5), among which POE(30) behenyl ether is preferred. Examples of commercially available polyoxyethylene alkyl ethers include NIKKOL® BB-30 (manufactured by Nikko Chemicals Co., Ltd.). Here, POE refers to a polyoxyethylene group, and the number in parentheses following POE represents the average number of moles of polyoxyethylene groups added to the compound.

[0013] From the viewpoint of emulsification stability, transparency, etc., the average number of moles of polyoxyethylene groups added to polyoxyethylene alkyl ether is preferably 20 or more, 21 or more, 25 or more, or 30 or more.

[0014] Furthermore, although (C) polyethylene glycol difatty acid ester, described later, is a hydrophilic nonionic surfactant, in this invention, component (A) does not include (C) polyethylene glycol difatty acid ester.

[0015] (A) component can be blended with one or more than one kind. The content rate of (A) component is preferably 0.2 to 1.4% by mass, more preferably 0.3 to 1.0% by mass, still more preferably 0.4 to 0.8% by mass based on the total mass of the cosmetic.

[0016] (B) Higher aliphatic alcohol having 12 or more carbon atoms The cosmetic according to the present invention contains a higher aliphatic alcohol (hereinafter sometimes referred to as (B) component). The (B) component used in the present invention is a higher aliphatic alcohol having 12 or more carbon atoms. (B) component can form an interfacial film of oil droplets together with (A) component. From the viewpoint of emulsion stability and the like, it is preferable that (B) component can form a solid or α-gel interfacial film at normal temperature or higher together with (A) component, for example, higher alcohols that are solid at normal temperature. Here, normal temperature means the range of 5°C to 35°C.

[0017] As such (B) component, higher aliphatic alcohols having 12 or more carbon atoms, preferably 16 or more carbon atoms can be used. Specific examples include lauryl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, myristyl alcohol, oleyl alcohol, cetostearyl alcohol, monostearyl glycerol ether (batyl alcohol), 2-decyltetradecynol, lanolin alcohol, cholesterol, hexyl dodecanol, isostearyl alcohol, and octyldodecanol.

[0018] Such (B) component has a straight-chain structure, a branched-chain structure, a cyclic structure, etc. for the hydrocarbon chain, but a straight-chain structure is preferable. Among them, from the viewpoint of usability and the like, higher alcohols having a straight-chain saturated alkyl group with 18 or more carbon atoms are preferable, and stearyl alcohol and behenyl alcohol are particularly preferable.

[0019] Furthermore, component (B) may be used alone or in combination of two or more types, but it is more preferable to use a combination of two or more types. Specifically, a combination of stearyl alcohol and behenyl alcohol is preferably used.

[0020] The content of component (B) is generally 0.5 to 20% by mass, preferably 1.0 to 10% by mass, based on the total mass of the cosmetic. In the present invention, it is preferable to adjust the blending ratio of component (A) and component (B) in order to form stable oil droplets, and it is preferable that the content of component (B) based on the total mass of the cosmetic is 3 times or more, and more preferably 5 times or more, than the content of component (A).

[0021] (C) Polyethylene glycol difatty acid ester The cosmetic composition according to the present invention comprises a polyethylene glycol difatty acid ester (hereinafter sometimes referred to as component (C)). This component (C) has a structure in which two polyethylene glycols are bonded to two acid groups of a difatty acid. In the present invention, the polyethylene glycol difatty acid ester has a polymerization number of 20 or less of polyoxyethylene glycol, and more preferably 15 or less. A higher polymerization number of polyoxyethylene glycol tends to result in poorer long-term stability.

[0022] The hydrocarbon chain derived from the fatty acid constituting component (C) preferably has 12 to 24 carbon atoms, and more preferably 16 to 20 carbon atoms. Furthermore, its structure is preferably linear. Specifically, examples of difatty acids constituting component (C) include distearic acid, dilauric acid, dipalmitic acid, and dimyristateic acid, with distearic acid and dilauric acid being preferred.

[0023] Examples of such (C) components include PEG-12 distearate, PEG-6 distearate, PEG-3 distearate, PEG-8 dilaurate, PEG-12 dimyristate, and PEG-3 dipalmitate, with PEG-12 distearate being preferred.

[0024] The content of component (C) is generally 0.03 to 1.0% by mass, preferably 0.05 to 0.5% by mass, based on the total mass of the cosmetic. In this invention, component (C) forms stable oil droplets together with component (A), and the stability is higher when the mixing ratio of component (A) and component (C) is within a specific range. Specifically, when the number of moles of component (A) and component (C), calculated based on their number-average molecular weights, are Ma and Mc, 0.1 <Mc / Ma<0.5 It is preferable that the following conditions be met.

[0025] (D) Oil The cosmetic composition according to the present invention contains (D) an oil component (hereinafter sometimes referred to as (D) component). The oil component mainly constitutes the oil phase of the cosmetic composition according to the present invention. The oil component can be arbitrarily selected from those commonly used in emulsified cosmetics. For example, liquid oils and fats, solid oils and fats, waxes, hydrocarbon oils, synthetic ester oils, etc. can be used.

[0026] Examples of liquid oils include avocado oil, camellia oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, peach kernel oil, wheat germ oil, sasanqua oil, castor oil, linseed oil, safflower oil, cottonseed oil, elm oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, cinnamon oil, Japanese tuni oil, jojoba oil, wheat germ oil, and triglycerin.

[0027] Examples of solid fats and oils include cocoa butter, coconut oil, horse fat, hydrogenated coconut oil, palm oil, beef tallow, sheep fat, hydrogenated beef tallow, palm kernel oil, lard, beef bone fat, Japanese wax kernel oil, hydrogenated oil, beef tallow, Japanese wax, and hydrogenated castor oil.

[0028] Examples of waxes include beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, privet wax, whale wax, montan wax, rice bran wax, lanolin, kapok wax, lanolin acetate, liquid lanolin, sugarcane wax, isopropyl lanolin fatty acid, hexyl laurate, reduced lanolin, jojoba wax, hard lanolin, shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, lanolin fatty acid polyethylene glycol, and POE hydrogenated lanolin alcohol ether.

[0029] Examples of hydrocarbon oils include liquid paraffin, ozokerite, squalane, pristane, paraffin, ceresin, squalene, petrolatum, microcrystalline wax, olefin oligomer, isododecane, isohexadecane, and the like.

[0030] Synthetic ester oils include isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, cholesteryl 12-hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glyceryl di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentaerythritol tetra-2-ethylhexanoate Glycerin tri-2-ethylhexanoate, glycerin trioctanoate, glycerin triisopalmitate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glycerin trimyristate, glyceride tri-2-heptylundecanoate, methyl castor oil fatty acid ester, oleyl oleate, acetoglyceride, 2-heptyl palmitate Examples include undecyl adipate, diisobutyl adipate, N-lauroyl-L-glutamic acid-2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, and triethyl citrate.

[0031] (E)Water The cosmetic composition according to the present invention comprises (E) water (hereinafter sometimes referred to as component (E)). The water that can be used in the present invention is not particularly limited, but water used in cosmetics, quasi-drugs, etc., can be used, for example, purified water, ion-exchanged water, tap water, etc.

[0032] (F) Other ingredients The cosmetic composition according to the present invention may contain various other ingredients as appropriate, depending on the intended use, as long as they do not affect the effects of the present invention. Examples of such ingredients include additives that are commonly found in cosmetics. Specifically, Amphoteric surfactants such as imidazoline-based amphoteric surfactants; Cationic surfactants such as alkyltrimethylammonium salts; Anionic surfactants; Powders such as talc; Moisturizing agents such as polyethylene glycol; Water-soluble polymers such as plant-derived polymers, starch-derived polymers, and vinyl-derived polymers; Film-forming agents such as anionic film-forming agents, cationic film-forming agents, and nonionic film-forming agents; UV absorbers such as benzoic acid-based UV absorbers; Metal ion chelating agents such as 1-hydroxyethane-1,1-diphosphonic acid; Amino acids, such as neutral amino acids and basic amino acids, and their salts or derivatives; Organic amines such as monoethanolamine; Polymer emulsions such as acrylic resin emulsions; Silicone elastomers such as dimethicone crosspolymer; Chelating agents; pH adjusters such as sodium lactate; Skin nutrients; Vitamins such as vitamin A, vitamin C, and their derivatives; Antioxidants such as tocopherols; Antioxidant agents such as phosphoric acid; Caffeine, Phellodendron bark extracts, and other various extracts; Preservatives such as ethylparaben; Anti-inflammatory agents such as glycyrrhizic acid derivatives; Whitening agents such as placental extract and magnesium ascorbate phosphate; Activators such as royal jelly; Blood circulation promoters such as nonylic acid vanenylamide; Anti-seborrheic agents such as sulfur; pigment; Pigments; and fragrance These are some examples.

[0033] Depending on their properties, various components can be incorporated, for example, into the aqueous phase as a continuous phase of an oil-in-water emulsion, and / or into the oil phase as a dispersed phase, i.e., within oil droplets.

[0034] Uses of oil-in-water emulsion compositions The cosmetic composition according to the present invention can be made transparent or translucent depending on its use, and can also exhibit an excellent feel when applied to the skin. Therefore, the cosmetic composition according to the present invention exhibiting such properties can be used, for example, as a base for a cosmetic composition, in particular as a base for a cosmetic composition applied to the skin. Here, the cosmetic composition applied to the skin can also include what is called a topical skin preparation.

[0035] The cosmetic product forms according to the present invention are not particularly limited, but examples include: facial cosmetics such as lotions, serums, emulsions, and masks; makeup cosmetics such as foundations, lipsticks, and eyeshadows; sunscreens; body cosmetics; fragrance cosmetics; skin cleansing products such as makeup removers and body shampoos; hair cosmetics such as hair liquids, hair tonics, hair conditioners, shampoos, rinses, and hair growth products; and ointments.

[0036] The cosmetic composition according to the present invention can be manufactured by any method, but can be prepared by known methods such as the agglomeration method or the dispersion method. By these methods, an oil-in-water emulsion composition containing ultrafine oil droplets with an average particle size of 100 nm or less can be prepared.

[0037] The agglomeration method is a colloid preparation method that utilizes interfacial chemical properties. It involves creating a supersaturated state from a uniformly dissolved state by some means, thereby introducing a dispersed phase. Specific methods include HLB temperature emulsification, phase inversion emulsification, non-aqueous emulsification, D-phase emulsification, and liquid crystal emulsification.

[0038] Dispersion is a method of micronizing clumps of dispersed phases by force. Specifically, it is a method of emulsifying using the crushing force of an emulsifier. The dispersion method preferably used in the present invention is a high-pressure emulsification dispersion method as described in Japanese Patent No. 3398171, from the viewpoint of transparency and low viscosity. Here, high-pressure emulsification is a method in which the aqueous phase component and the oil phase component are pre-emulsified as needed using a homomixer or the like, and an emulsion having fine emulsion particles is obtained by applying high shear force under high pressure using a high-pressure homogenizer such as a Manton Gorin, French press, or microfluidizer.

[0039] When obtaining the oil-in-water emulsion composition according to the present invention by high-pressure emulsification, it is preferable to prepare a mixture containing water, an ionic surfactant, a nonionic surfactant, a higher alcohol, and an oil component, to emulsify the mixture under high pressure at a pressure of 50 MPa or higher, 80 MPa or higher, or 100 MPa or higher to prepare an emulsion, and then to prepare the composition by blending an organic acid or its salt or a derivative thereof into the emulsion. By preparing a mixture containing water, a surfactant, a higher alcohol, and an oil component before emulsification, the surfactant and higher alcohol are more easily incorporated into the interfacial film of the oil droplets after emulsification.

[0040] Here, the mixture may be prepared by mixing water, surfactant, higher alcohol, and oil at the same time, or by preparing an oil-soluble solution containing a nonionic surfactant, higher alcohol, and oil, and a water-soluble solution containing water and other surfactants separately, and then adding the oil-soluble solution to the water-soluble solution to prepare the mixture. Furthermore, heating treatment may be applied as needed during the preparation of the mixture. [Examples]

[0041] The present invention will be specifically described based on the following examples, but the present invention is not limited to these examples. Unless otherwise specified, the content is expressed as mass % relative to the total mass.

[0042] [Examples 1-7, Comparative Examples 1-2] Cosmetic compositions for each example and each comparative example were prepared using the formulations shown in Table 1.

[0043] Furthermore, the performance of these cosmetics was evaluated as follows.

[0044] [Viscosity stability] Each sample was left to stand at 25°C. At 1 week, 2 weeks, and 4 weeks of standing time, each sample was held at 30°C for 30 minutes, and then its viscosity was measured using a B-type viscometer (rotor No. 3, 12 rpm, 1 minute). The standard deviation and mean value were calculated from the viscosity measurements at each of the 1-week, 2-week, and 4-week time points, and the coefficient of variation (cv value) was calculated.

[0045] [Moisturizing] For each sample, 18 μL of the sample was uniformly spread over a 3 cm x 3 cm area on the inner forearm using a pipette, and the moisture content was measured after 2 hours using a corneometer (AU). Each sample was measured twice, and the average values ​​are shown in the table. A blank sample (without any application of the sample) was also measured as a blank for evaluating moisturizing properties.

[0046] [Table 1] *1: POE(20) behenyl ether: Number average molecular weight 1207 *2: PEG-12 distearate: Number average molecular weight 1078 *3: PEG-150 distearate: Number average molecular weight 7157 *4: PEG-8 dilaurate: Number average molecular weight 734

[0047] [Example 8, Comparative Example 3] Cosmetics for Example 8 and Comparative Example 3 were prepared using the formulations shown in Table 2.

[0048] Furthermore, the moisturizing properties of these cosmetics were evaluated. For each sample, 18 μL of the sample was uniformly spread over a 3 cm x 3 cm area on the inner forearm using a pipette. The moisture content was measured using a corneometer 4 hours after application. Additionally, the sample was rinsed with water, and the moisture content was measured again 10 minutes later. Each sample was measured five times, and the average values ​​are shown in the table. A blank sample (without application) was also measured as a blank for evaluating moisturizing properties.

[0049] [Table 2]

Claims

1. (A) Hydrophilic nonionic surfactant, (B) Higher aliphatic alcohols with 12 or more carbon atoms, (C) Polyethylene glycol difatty acid ester with a polymerization number of 20 or less of polyoxyethylene glycol, (D) Oils, and (E) Water An oil-in-water emulsion cosmetic containing [the specified ingredient].

2. The cosmetic composition according to claim 1, wherein component (A) is selected from the group consisting of polyoxyethylene alkyl ether, polyglycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene lanolin / lanolin alcohol / beeswax derivative, polyoxyethylene castor oil / hydrogenated castor oil, polyoxyethylene sterol / hydrogenated sterol, polyethylene glycol fatty acid ester, and polyoxyethylene glyceryl isostearate.

3. The cosmetic composition according to claim 1 or 2, wherein component (A) is selected from the group consisting of alkyl ether surfactants having a linear alkyl group with 16 or more carbon atoms, and alkyl ester surfactants.

4. The cosmetic composition according to claim 1 or 2, wherein the hydrocarbon chain of component (B) has a linear structure.

5. (B) The cosmetic composition according to claim 1 or 2, wherein component (B) is a mixture of two or more higher aliphatic alcohols.

6. The cosmetic composition according to claim 1 or 2, wherein the hydrocarbon chain derived from fatty acids constituting component (C) has a linear structure.

7. The cosmetic composition according to claim 1 or 2, wherein the content of component (A) is 0.2 to 1.4% by weight, based on the total mass of the cosmetic composition.

8. The cosmetic composition according to claim 1 or 2, wherein the content of component (B), based on the total mass of the cosmetic composition, is three times or more the content of component (A).

9. When the number of moles of component (A) and component (B) contained in the cosmetic composition are calculated based on their number-average molecular weights, let Ma and Mc be respectively, the ratio of Mc to Ma, Mc / Ma, has the following relationship: 0.1<Mc / Ma<0.5 A cosmetic composition according to claim 1 or 2, satisfying the requirements.

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