Oil-in-water emulsion

Abstract

An oil-in-water emulsion comprising (a) a polyglycerol straight-chain fatty acid ester having an HLB value of 12 or greater; (b) a sucrose fatty acid ester having an HLB value of 7 or lower; (c) a fatty acid monoamide -based anionic surfactant; (d) a polysaccharide; (e) an oil agent; and (f) water.

Description

DESCRIPTIONTitle of InventionOIL-IN-WATER EMULSIONTechnical Field

[0001] The present invention relates to an oil-in-water emulsion.Background Art

[0002] Cosmetic compositions are required to have excellent feel during use and high stability. JP-A-2002-87933 discloses a transparent or translucent cosmetic containing one or more kinds of nonionic surfactants selected from polyglycerol fatty acid esters, sucrose fatty acid esters having a HLB value of 8 to 20, and one or more kinds selected from N-long-chain acyl amino acids and their salts. The objective of this combination is to provide a cosmetic with good storage stability and good solubilizing power for poorly water-soluble ingredients.Technical Problem

[0003] The quality of feel during use required for a cosmetic composition includes freshness, roundness and softness on skin. Softness can generally be imparted by increasing the content of polar oils and polyols, but polar oils and polyols also tend to reinforce the richness, resulting in lower freshness. Roundness can be imparted by addition of polysaccharides. However, polysaccharides also tend to produce a filmy residue and reduce softness. It is therefore difficult to simultaneously achieve the qualities of freshness, roundness and softness in a cosmetic composition, especially in an oil-in-water emulsion. Freshness is the perception of a light sensation duringapplication, whereas roundness is a sensation of cushioning thickness during application. The term "softness on skin" refers to the softness on the skin after application.Summary of Invention

[0004] So, there is still a need to provide a cosmetic composition under the form of an oil-in-water emulsion which exhibits excellent freshness, roundness and softness on skin after application, while also having high stability.Solution to Problem

[0005] The oil-in-water emulsion of the invention exhibits excellent freshness, roundness and softness on skin after application, as well as high stability.

[0006] The oil-in-water emulsion of the invention has excellent roundness because it contains (d) a polysaccharide. As mentioned above, when an oil-in-water emulsion contains a polysaccharide it tends to lack softness on skin, but the present inventors have found that by using both (a) a polyglycerol straight-chain fatty acid ester having an HLB value of 12 or greater and (b) a sucrose fatty acid ester having an HLB value of 7 or lower, as nonionic surfactants, and (c) a fatty acid monoamide -based anionic surfactant as an anionic surfactant, it is possible to form a stable emulsified system that imparts softness on skin while also providing a feeling of freshness.

[0007] So the present invention provides the following.An oil-in-water emulsion comprising:(a) a polyglycerol straight-chain fatty acid ester having an HLB value of 12 or greater;(b) a sucrose fatty acid ester having an HLB value of 7 or lower;(c) a fatty acid monoamide -based anionic surfactant;(d) a polysaccharide;(e) an oil agent; and(f) water.The component listed as (a) above will hereunder be referred to as "component (a)", and likewise for the other components.

[0008] The present invention also provides the following specific embodiments.In a particular embodiment, the oil-in-water emulsion is further characterized by the content of component (e) that is 1 mass% or greater, preferably in the range of 1 mass% to 25 mass%, especially 3 to 20 mass%, based on the total mass of the oil-in-water emulsion.

[0009] In a particular embodiment, the oil-in-water emulsion further comprises a polyhydric alcohol.

[0010] In a particular embodiment, the oil-in-water emulsion comprises a component (e) that has an IOB value of 0.1 to 0.15.

[0011] In a particular embodiment, the oil-in-water emulsion comprises a component (e) that comprises an oil having an IOB value of lower than 0.1 and an oil having an IOB value of 0.1 or greater.

[0012] In a particular embodiment, the oil-in-water emulsion comprises a component (d) that is at least one selected from the group consisting of cellulose derivatives and polysaccharides comprising glucuronic acid and a cyclic aldohexose as constituent monosaccharides.

[0013] In a particular embodiment, the oil-in-water emulsion is characterized as follows: component (a) comprises polyglyceryl- 10oleate, component (b) comprises sucrose distearate, component (c) comprises a stearic acid monoamide-based anionic surfactant and component (d) comprises at least one selected from the group consisting of cellulose ethers, hydrophobized cellulose ethers and polysaccharides comprising glucuronic acid and a cyclic aldohexose as constituent monosaccharides.In a particular embodiment, the oil-in-water emulsion comprises 0.1 to 10.0% of component (a), 0.1 to 10.0% of component (b), 0.01 to 1.0% of component (c) and 0.01 to 1.0% of component (d), based on the total mass of the oil-in-water emulsion.

[0014] In a particular embodiment, the oil-in-water emulsion comprises an oil globule with a cumulant diameter of 300 nm or smaller based on dynamic light scattering.

[0015] The present invention also concerns a cosmetic process for caring for and / or making-up keratinic materials, wherein the cosmetic process comprises the application onto keratinic materials, in particular onto skin, of the oil-in-water emulsion as defined above.

[0016] In a particular embodiment, the cosmetic process is characterized by the fact that the oil-in-water emulsion provides the keratinic materials on which it is applied with freshness, roundness and softness.Advantageous Effects of Invention

[0017] According to the invention there is provided a cosmetic composition under the form of an oil-in-water emulsion which exhibits excellent freshness, roundness and softness on skin after application, while also having high stability.Detailed Description of the Invention

[0018] Preferred embodiments of the invention will now be described in detail. However, the present invention is not limited to the described embodiments.

[0019] The oil-in-water emulsion according to the invention contains (a) a polyglycerol straight-chain fatty acid ester having an HLB value of 12 or greater; (b) a sucrose fatty acid ester having an HLB value of 7 or lower; (c) a fatty acid monoamide-based anionic surfactant; (d) a polysaccharide; (e) an oil agent; and (f) water.

[0020] It is a feature of this embodiment that component (a), which functions as a nonionic surfactant, is combined with component (b) which likewise functions as a nonionic surfactant, and component (c) which is an anionic surfactant.

[0021] In an embodiment, the poly glycerol straight-chain fatty acid ester having an HLB value of 12 or greater (component a) is an ester composed of polyglycerol and a straight-chain fatty acid of 12 to 24, 14 to 22 or 16 to 20 carbon atoms, for example. Such a straight-chain fatty acid is either saturated or unsaturated. The straight-chain fatty acid may either have or lack hydroxyl groups. When the straight-chain fatty acid is a straight-chain unsaturated fatty acid, the straight-chain unsaturated fatty acid has for example 1 to 3, 1 to 2 or 1 unsaturated bond.Examples for straight-chain fatty acids to compose a polyglycerol straight-chain fatty acid ester include lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, a-linolenic acid, y-linolenic acid, arachidic acid, arachidonic acid, behenic acid and ricinolic acid. These fatty acids having one or more hydrogens of ahydrocarbon group in the fatty acid replaced by a hydroxyl group (hydroxy fatty acids) may also be used, and a straight-chain fatty acid may also be a condensation product of a hydroxy fatty acid. The straight-chain fatty acid is preferably a straight-chain unsaturated fatty acid.

[0022] In particular, the number of glycerol units in the polyglycerol straight-chain fatty acid ester (or "glycerol polymerization degree") is of 2 to 20, 4 to 18, 5 to 16, 6 to 14 or 8 to 12, for example.

[0023] In an embodiment, the polyglycerol straight-chain fatty acid ester is a polyglycerol straight-chain fatty acid monoester having one ester bond, or it has 2, 3 or more ester bonds. In particular, the polyglycerol straight-chain fatty acid ester has 1 to 3 ester bonds, for example.

[0024] Examples of polyglycerol straight-chain fatty acid esters include polyglyceryl-5 laurate, polyglyceryl-6 laurate, polyglyceryl- 10 laurate, polyglyceryl-5 myristate, polyglyceryl-6 myristate, polyglyceryl- 10 myristate, polyglyceryl- 10 palmitate, polyglyceryl-5 stearate, polyglyceryl-6 stearate, polyglyceryl- 10 stearate, polyglyceryl-5 oleate, polyglyceryl- 10 oleate and mixtures thereof.

[0025] As mentioned above, the polyglycerol straight-chain fatty acid ester is of many different types depending on the type of fatty acid, and since the structure will differ depending on the glycerol polymerization degree even if the same fatty acid is used, it has different HLB values, though the HLB value of component (a) is 12 or greater. In a particular embodiment, the HLB value of the polyglycerol straight-chain fatty acid ester is comprised between 12 to 18, 12 to 15 or 12 to 14. Inparticular, component (a) is a single type of polyglycerol straight-chain fatty acid ester, or a combination of several different types. When several different polyglycerol straight-chain fatty acid esters are used, it is sufficient for the weighted average of their HLB values to be 12 or greater, and therefore polyglycerol straight-chain fatty acid esters with HLB values of lower than 12 may also be included.

[0026] The HLB value is an index representing the ratio of the relative affinity of a surfactant with respect to both liquids in an oil-aqueous system, and the HLB value used for the purpose of the invention is based on the definition of Griffin, at 25°C. The Griffin HLB value is described in J. Soc. Cosm. Chem., 1954, 5:249-256.

[0027] In an embodiment, the content of component (a) ranges from 0.1 to 10.0 mass% or 0.5 to 5.0 mass%, based on the total mass of the oil-in-water emulsion.

[0028] In an embodiment, the sucrose fatty acid ester having an HLB value of 7 or lower (component b) is a sucrose ester of a fatty acid with 12 to 24, 16 to 22 or 16 to 20 carbon atoms, for example. The fatty acid is saturated or unsaturated, and straight-chain or branched. The fatty acid may either have or lack hydroxyl groups. Examples for fatty acids to compose a sucrose fatty acid ester include lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, isostearic acid, oleic acid, linoleic acid, a-linolenic acid, y-linolenic acid, arachidic acid, arachidonic acid, behenic acid and ricinolic acid. These fatty acids having one or more hydrogens of a hydrocarbon group in the fatty acid replaced by a hydroxyl group (hydroxy fatty acids) may also be used, and a fatty acid may also be a condensation product of a hydroxy fattyacid. The fatty acid is preferably a straight-chain fatty acid, and more preferably a straight-chain saturated fatty acid.

[0029] In an embodiment, the sucrose fatty acid ester has one ester bond, or it has 2, 3 or more ester bonds. For example, the sucrose fatty acid ester has 1 to 4 or 1 to 3 ester bonds. The sucrose fatty acid ester is preferably a sucrose fatty acid diester.

[0030] Examples of sucrose fatty acid esters include sucrose monolaurate, sucrose dilaurate, sucrose trilaurate, sucrose tetralaurate, sucrose monopalmitate, sucrose dipalmitate, sucrose tripalmitate, sucrose tetrapalmitate, sucrose monomyristate, sucrose dimyristate, sucrose trimyristate, sucrose tetramyristate, sucrose monopalmitate, sucrose dipalmitate, sucrose tripalmitate, sucrose tetrapalmitate, sucrose monostearate, sucrose distearate, sucrose tristearate, sucrose tetrastearate and mixtures thereof.

[0031] The HLB value of a sucrose fatty acid ester may have various different values, but the HLB value of component (b) is 7 or lower. In a particular embodiment, the HLB value of the sucrose fatty acid ester is comprised between 1 to 7, 3 to 7 or 4 to 7. In an embodiment, component (b) is a single type of sucrose fatty acid ester, or a combination of several different types. When several different sucrose fatty acid esters are used, it is sufficient for the weighted average of their HLB values to be 7 or lower, and therefore sucrose fatty acid esters with HLB values of greater than 7 may also be included.

[0032] In a specific embodiment, the content of component (b) ranges from 0.1 to 10.0 mass% or 0.2 to 2.0 mass%, based on the total mass of the oil-in-water emulsion.

[0033] As used herein, a "fatty acid monoamide-based anionic surfactant" (component c) is an anionic surfactant which is a condensate of a fatty acid and an amino group-containing compound, having a "fatty acid monoamide" structure with one amide bond. A fatty acid monoamide-based anionic surfactant has an acyl group derived from a fatty acid.

[0034] Since a fatty acid monoamide -based anionic surfactant is an anionic surfactant, it has an ionic dissociable group (anionic dissociable group) that dissociates in water to form an anion. An ionic dissociable group, for the present purpose, is a group that can dissociate into an ion in water. Anionic dissociable groups include carboxyl (-COOH), sulfo (-SO3H), sulfate (-O-SO3H), phosphate (-OPO(OH)2) and their salts (for example, alkali metal salts such as sodium salts, and potassium salts, alkaline earth metal salts such as magnesium salts and calcium salts, ammonium salts, and salts with organic bases such as tromethamine and arginine). In a particular embodiment, the number of anionic dissociable groups in the fatty acid monoamide -based anionic surfactant is one or more, and up to 5, 4, 3 or 2, for example. The number of anionic dissociable groups in the anionic surfactant is 1 to 5, 2 to 5, 1 to 4 or 2 to 4, for example.

[0035] The fatty acid composing the fatty acid monoamide-based anionic surfactant is saturated or unsaturated, and straight-chain or branched. In particular, the number of carbon atoms of the fatty acid is of 12 to 24, 14 to 22 or 16 to 20, for example. Examples of fatty acids include lauric acid, myristic acid and stearic acid. The fatty acid is preferably a straight-chain saturated fatty acid. The fatty acidmonoamide -based anionic surfactant is, for example, a stearic acid monoamide -based anionic surfactant.

[0036] A compound with an amino group to compose the fatty acid monoamide -based anionic surfactant is a compound having an amino group and the aforementioned anionic dissociable group. That is, the fatty acid monoamide-based anionic surfactant is an anionic surfactant consisting of a monoamide of (i) a compound having an amino group and an anionic dissociative group and (ii) a fatty acid. Examples of such compounds include compounds wherein the anionic dissociable group is carboxyl or its salt (e.g. an amino acid such as glutamic acid or lysine), and compounds wherein the anionic dissociable group is an anionic dissociable group other than carboxyl, or its salt (such as a sulfo, sulfate or phosphate group, or a salt thereof) (an example of which is taurine, as a compound with an amino and sulfo group).

[0037] From the viewpoint of easy synthesis of the monoamide, when the compound with an amino group is an amino acid or its salt, the amino acid is preferably a neutral amino acid (an amino acid with equal numbers of carboxyl groups and amino groups, and preferably an amino acid with one of each functional group), or an acidic amino acid (an amino acid with more carboxyl groups than amino groups, and preferably an amino acid with one amino group). Specifically, the anionic surfactant is preferably one comprising a monoamide, as the reaction product of a neutral or acidic amino acid and a fatty acid, or its salt. Neutral amino acids include alanine, glycine, leucine, phenylalanine, serine and threonine, and acidic amino acids include aspartic acid and glutamic acid.

[0038] From the viewpoint of easy synthesis of the monoamide, when the compound with an amino group is a compound having an anionic dissociable group other than a carboxyl group, or its salt, the compound is preferably one having one amino group, and having 1, 2 or more anionic dissociable groups other than a carboxyl group, or their salts.

[0039] Examples of fatty acid monoamide -based anionic surfactants include N-acyl glutamates such as N-cocoyl glutamate (such as sodium N-coco fatty acid acyl-L-glutamate), N-lauroyl glutamate, N-myristoyl glutamate (N-myristoyl— L-glutamate) and N-stearoyl glutamate (such as sodium N-stearoyl glutamate); N-acylglycine salts such as N- lauroylglycine salts, N-myristoylglycine salts and N-stearoylglycine salts; N-acylalanine salts such as N-lauroylalanine salts, N- myristoylalanine salts and N-stearoylalanine salts; N-acyl aspartates such as N-lauroyl aspartate, N-myristoyl aspartate and N-stearoyl aspartate; and long-chain acyl lower alkyl-type taurine salts such as N- cocoyl-N-methyltaurine salts, N-lauroyl-N-methyltaurine salts, N- myristoyl-N-methyltaurine salts, N-stearoyl-N-methyltaurine salts (such as sodium N-stearoyl-N-methyltaurate), N-cocoyltaurine salts and mixtures thereof. Component (c) is a single type of the aforementioned fatty acid monoamide -based anionic surfactants, or a combination of several different types. The salts of N-acyl glutamates, N-acylglycine salts, N-acylalanine salts, N-acyl aspartates, and long- chain acyl lower alkyl-type taurine salts include alkali metal salts such as sodium salts and potassium salts, alkaline earth metal salts such as magnesium salts and calcium salts, ammonium salts, and salts with organic bases such as tromethamine and arginine, as mentioned above.

[0040] In an embodiment, the content of component (c) ranges from 0.01 to 1.00 mass% or 0.05 to 0.50 mass%, based on the total mass of the oil-in-water emulsion.

[0041] The oil-in-water emulsion has excellent roundness because it includes a polysaccharide (component (d)). Based on investigation by the present inventors, sufficient roundness is not exhibited when the oil-in-water emulsion does not contain component (d). The polysaccharide acts as a thickener, but based on investigation by the present inventors, the roundness is inadequate if the oil-in-water emulsion contains a different component that can act as a thickener instead of component (d) (such as a carbomer). In an embodiment, the polysaccharide (d) is one or more types selected from the group consisting of cellulose derivatives and polysaccharides comprising a uronic acid as a constituent monosaccharide. In another embodiment, the polysaccharide (d) also contains quince seed extract (pyrus cydonia seed extract) or Hibiscus abelmoschus extract.

[0042] In a specific embodiment, the cellulose derivative is a water- soluble cellulose derivative (cellulose with reduced crystallinity for water solubility). In another embodiment, the cellulose derivative is an etherified cellulose (a cellulose ether). A cellulose ether can be obtained, for example, by reacting sodium hydroxide-treated cellulose with an etherifying agent such as methyl chloride, propylene oxide or ethylene oxide. Examples of cellulose ethers include alkyl celluloses having the hydrogens of at least some of the hydroxyl groups of the cellulose replaced with alkyl groups (such as methyl cellulose, substituted with methyl groups), hydroxyalkylcelluloses having thehydrogens of at least some of the hydroxyl groups of the cellulose replaced with hydroxyalkyl groups (such as hydroxyethylcellulose, substituted with hydroxyethyl groups, or hydroxypropyl cellulose, substituted with hydroxypropyl groups), hydroxyalkyl alkylcelluloses having the hydrogens of at least some of the hydroxyl groups of the cellulose replaced with alkyl groups and the hydrogens of at least some of the hydroxyl groups of the cellulose replaced with hydroxyalkyl groups (such as hydroxypropyl methylcellulose, substituted with methyl and hydroxypropyl groups), and mixtures thereof.

[0043] In an embodiment, the hydroxyalkyl groups of hydroxyalkylcellulose is hydroxyalkyl groups of 1 to 6 carbon atoms or 2 to 4 carbon atoms. For example, hydroxyethylcellulose has hydroxyalkyl groups of 2 carbon atoms.

[0044] In an embodiment, the alkyl and hydroxyalkyl groups of hydroxyalkyl alkylcelluloses are alkyl groups of 1 to 6 or 1 to 3 carbon atoms and hydroxyalkyl groups of 1 to 6 or 2 to 4 carbon atoms, respectively. Hydroxypropyl methylcellulose, for example, has alkyl groups of 1 carbon atom and hydroxyalkyl groups of 3 carbon atoms.

[0045] In another embodiment, the cellulose derivative is a hydrophobized cellulose ether. A hydrophobized cellulose ether is a cellulose ether modified with a hydrophobic group (such as a long chain alkyl group). Modification with hydrophobic groups includes etherification with hydrophobic groups. In a specific embodiment, the hydrophobized cellulose ether is a cellulose ether modified with an alkyl group of 10 to 30, 12 to 28 or 14 to 22 carbon atoms. Examples of hydrophobized cellulose ethers include hydrophobizedhydroxyalkylcelluloses such as hydrophobized hydroxyalkyl alkylcelluloses.

[0046] Examples of hydrophobized hydroxyalkylcelluloses include cetyl hydroxyethylcellulose having alkyl groups of 16 carbon atoms (- C16H35) bonded to portions of hydroxyethylcellulose. Examples of hydrophobized hydroxyalkyl alkylcelluloses include hydroxypropyl methylcellulose stearoxy ether having alkyl groups of 18 carbon atoms (-C18H37) bonded to portions of hydroxypropyl methylcellulose.

[0047] For a polysaccharide comprising a uronic acid as a constituent monosaccharide (hereunder also referred to as "uronic acid-comprising polysaccharide"), the uronic acid included as a constituent monosaccharide is a saccharide derivative with a carboxy group, being a sugar oxidation product. Examples of uronic acids include glucuronic acid, galacturonic acid, mannuronic acid, arabinonic acid, fructuronic acid, tagaturonic acid, iduronic acid and guluronic acid. A uronic acidcomprising polysaccharide may include a single type of uronic acid as the constituent monosaccharide, or it may include two or more different types. The uronic acid is preferably glucuronic acid. In other words, the uronic acid-comprising polysaccharide is preferably a polysaccharide containing glucuronic acid as the constituent monosaccharide.

[0048] The uronic acid-comprising polysaccharide also preferably further includes a cyclic aldohexose compound as constituent monosaccharide. In this case the uronic acid-comprising polysaccharide is a polysaccharide comprising a uronic acid and a cyclic aldohexose compound as the constituent monosaccharides, and itis preferably a polysaccharide comprising glucuronic acid and a cyclic aldohexose compound as the constituent monosaccharides.

[0049] The cyclic aldohexose compound is preferably pyranose, i.e. a six-membered ring composed of 5 carbon atoms and one oxygen atom. Examples of cyclic aldohexose compounds include allose, altrose, glucose, mannose, gulose, idose, galactose and talose. The uronic acidcomprising polysaccharide may include a single type of the aforementioned cyclic aldohexose compounds as the constituent monosaccharide, or two or more types. The cyclic aldohexose compound is preferably either or both glucose and mannose. The uronic acid-comprising polysaccharide is preferably a polysaccharide comprising at least one of glucuronic acid, glucose and mannose as constituent monosaccharides.

[0050] In a particular embodiment, the uronic acid-comprising polysaccharide also includes other constituent monosaccharides other than the aforementioned uronic acid and cyclic aldohexose compounds. Examples of other constituent monosaccharides include cyclic deoxyaldohexose compounds, cyclic aldopentose compounds and cyclic aminoaldohexose compounds.

[0051] A cyclic deoxyaldohexose compound is preferably a cyclic structure derived from a deoxyaldohexose (or "deoxy sugar"), i.e. pyranose with a six-membered ring composed of 5 carbon atoms and one oxygen atom. Cyclic deoxyaldohexose compounds include fucose, fiiculose and rhamnose. In an embodiment, the uronic acid-comprising polysaccharide includes a single type of the aforementioned cyclic deoxyaldohexose compounds as the constituent monosaccharide, ortwo or more types. The cyclic deoxyaldohexose compound is preferably either or both fucose and rhamnose.

[0052] A cyclic aldopentose compound is a cyclic pentose having a six-membered ring composed of 5 carbon atoms and one oxygen atom or a five-membered ring composed of 4 carbon atoms and one oxygen atom, derived from aldopentose. Cyclic deoxyaldohexose compounds include ribose, arabinose, xylose and lyxose. In an embodiment, the uronic acid-comprising polysaccharide includes a single type of the aforementioned cyclic aldopentose compounds as the constituent monosaccharide, or two or more types. The cyclic aldopentose compound is preferably xylose.

[0053] A cyclic aminoaldohexose compound is preferably a cyclic structure derived from an aminoaldohexose (a compound wherein one or more hydroxyl groups of an aldohexose are replaced with amino groups, also referred to as "amino sugar"), i.e. pyranose with a sixmembered ring composed of 5 carbon atoms and one oxygen atom. Examples of cyclic aminoaldohexose compounds include glucosamine and galactosamine. In an embodiment, the uronic acid-comprising polysaccharide includes a single type of the aforementioned cyclic aminoaldohexose compounds as the constituent monosaccharide, or two or more types. The cyclic aminoaldohexose compound is preferably glucosamine.

[0054] In another embodiment, the uronic acid-comprising polysaccharide is a biologically-derived polysaccharide. Here, "biologically-derived" means extracted from a plant (plant-derived) or fungi (fungi-derived, such as from Basidiomycota or Ascomycota), byan extraction process. As used herein, "microbial" substances, i.e. substances obtained by purification and processing of substances (such as a polymer substances) produced by microbes, are also considered to be "biologically-derived".

[0055] When the uronic acid-comprising polysaccharide contains glucuronic acid as a uronic acid, the molar percentage of glucuronic acid is preferably 10 mol% or greater, 15 mol% or greater or 20 mol% or greater, with respect to the total moles of the constituent monosaccharide.

[0056] According to a preferred mode of the invention, the uronic acid-comprising polysaccharide comprises glucuronic acid, a cyclic aldohexose compound, a cyclic deoxyaldohexose compound (such as rhamnose) and / or a cyclic aldopentose compound (such as xylose) as constituent monosaccharides. Most preferred uronic acid-comprising polysaccharides are polysaccharides comprising glucuronic acid, mannose and xylose as constituent monosaccharides.

[0057] Tremella fuciformis polysaccharides are examples of polysaccharides comprising glucuronic acid, mannose and xylose as constituent monosaccharides. Tremella fuciformis polysaccharides are polysaccharides extracted from Tremella fuciformis. Tremella fuciformis polysaccharides have a main chain with mannose as the constituent monosaccharide and side chains with xylose and glucuronic acid as structural units. Among Tremella fuciformis polysaccharides, the molar percentage of glucuronic acid with respect to the number of moles of constituent monosaccharides is approximately 20 mol%. Examples of Tremella fuciformis polysaccharides include the tradename TremoistRTP (INCI name: Tremella fuciformis polysaccharide) (product of Nippon Seika Co., Ltd.). The average molecular weight of TremoistRTP is 1,000,000 or greater.

[0058] Other examples of uronic acid-comprising polysaccharides include polysaccharides comprising glucuronic acid, glucose and mannose as constituent monosaccharides (such as xanthan gum), polysaccharides comprising glucuronic acid, glucose and rhamnose as constituent monosaccharides (such as gellan gum), polysaccharides comprising galacturonic acid, galactose and fucose as constituent monosaccharides (such as biosaccharide gum-1), and polysaccharides comprising glucuronic acid and glucosamine as constituent monosaccharides (such as hyaluronic acid and its salts).

[0059] The polysaccharide is preferably one or more types selected from the group consisting of cellulose ethers, hydrophobized cellulose ethers, and polysaccharides comprising glucuronic acid and a cyclic aldohexose compound as constituent monosaccharides.

[0060] In an embodiment, the total content of component(s) (d) ranges from 0.01 to 1.00 mass% or 0.05 to 0.50 mass%, based on the total mass of the oil-in-water emulsion.

[0061] In an embodiment, the oil agent (component (e)) is a liquid oil agent or a paste oil agent, but it is preferably a liquid oil agent. As used herein, a "liquid oil agent" is an oil agent which is liquid at ordinary temperature (in the range of 15 to 25°C) and ordinary pressure (1 atmosphere).

[0062] Oil agents include non-volatile hydrocarbon oils, higher alcohols, ester oils, ether oils and vegetable oils, for example.

[0063] Examples of non-volatile hydrocarbon oils include squalane, liquid paraffin, vaseline, polybutene, polyisobutene, hydrogenated polyisobutene, hydrogenated polydecene, olefin oligomers, and mixtures of the same.

[0064] Higher alcohols are aliphatic monoalcohols of 6 or more carbon atoms, and for example are aliphatic monoalcohols of 12 to 28 carbon atoms. Examples of higher alcohols include octyl alcohol, dodecyl alcohol, oleyl alcohol, octyldodecanol, hexyldecanol, isostearyl alcohol and decyltetradecanol, as well as mixtures thereof.

[0065] An ester oil is an ester of a fatty acid and an alcohol. The number of carbon atoms of a fatty acid composing an ester oil isfor example 6 to 18 or 7 to 15. In an embodiment, the alcohol composing an ester oil is a monohydric to trihydric alcohol, for example.

[0066] Examples of ester oils include fatty acid alkyl esters such as isoamyl laurate, hexyl laurate, ethylhexyl palmitate, ethylhexyl stearate, isopropyl myristate, 2-octyldodecyl myristate, cetyl 2- ethylhexanoate, isononyl isononanoate, isotridecyl isononanoate, alkyl coco(caprylatesZcaprates) and alkyl coco-caprylates; glycerol tri-fatty acid esters (also known as triglyceride oils) such as glyceryl tri-2- ethylhexanoate, glyceryl tribehenate, glyceryl tri(caprylateZcaprate) and triheptanoin; polyglycerol tri- or greater fatty acid esters such as polyglyceryl-2 triisostearate, polyglyceryl-2 tetraisostearate and polyglyceryl- 10 decaisostearate; propylene glycol fatty acid esters such as propyleneglycol dicaprylate and propyleneglycol dicaprate; carbonic acid esters such as dicaprylyl carbonate; benzoic acid derivatives such as diisostearyl malate and alkyl (Cl 2- 15) benzoate; salicylic acidderivatives such as homosalate acid and ethylhexyl salicylate; cinnamic acid derivatives such as octyl methoxycinnamate, isopropyl methoxycinnamate, isoamyl methoxycinnamate, cinnoxate, DEA methoxycinnamate, diisopropyl methylcinnamate, glyceryl-ethyl hexanoate-dimethoxycinnamate and di-(2-ethylhexyl)-4'- methoxybenzalmalonate; P,P-diphenyl acrylate derivatives such as octocrylene; and mixtures thereof.

[0067] Dicaprylyl ether is an example of an ether oil.

[0068] Examples of vegetable oils include meadowfoam seed oil, olive fruit oil, jojoba seed oil, camellia oil, coconut oil, macadamia nut oil, rosehip oil, avocado oil, sunflower seed oil, rice bran oil, castor oil and almond oil, as well as mixtures thereof.

[0069] Component (e) is used as a single type among the components (oils) mentioned above, or multiple types are used in combination. Component (e) preferably contains one or more selected from the group consisting of squalane, glyceryl tri(caprylate / caprate) and cocoalkyl (caprylate / caprate), ethylhexyl stearate and ethylhexyl palmitate.

[0070] The IOB value of component (e) is preferably 0.1 to 0.15 or 0.12 to 0.14. The IOB value is the Inorganic-Organic Balance (IOB) obtained based on the organic conception diagram described in Kouda, Y, "Yuki Gainenzu - Kiso to Ouyo", pp.11-17, Sankyo Publishing, 1984, for example. When component (e) is a mixture of multiple components (multiple oils), the IOB value of component (e) is the average IOB (arithmetic mean) of the IOB values of all of the components.

[0071] According to an embodiment, the method for limiting the IOB value of component (e) to within the aforementioned numerical range is a method using only oils with IOB values in the aforementioned numerical range, or a method of combining multiple oils with different IOB values. According to one embodiment, component (e) preferably includes multiple oils with different IOB values. More specifically, component (e) preferably includes (i) an oil having an IOB value of lower than 0.1 and (ii) an oil having an IOB value of 0.1 or greater. According to an embodiment, the IOB value of (i) is 0.08 or lower or 0.05 or lower. According to another embodiment, the IOB value of (ii) is greater than 0.1, 0.12 or greater, 0.15 or greater, 0.20 or greater or 0.25 or greater.

[0072] Examples are squalane (SQUALANE VEGETAL (EX PERHYDROSQUALENE)) with an IOB value of 0, caprylic / capric triglyceride (GLYCEROL TRICAPRATE / CAPRYLATE MB) with an IOB value of 0.30, coco-caprylate / caprate (CETIOL LC MB) with an IOB value of 0.14, ethylhexyl stearate (STEARATE ETHYL 2 HEXYL (DUBSO) MB) with an IOB value of 0.12, and ethylhexyl palmitate (PALMITATE D ETHYLE 2 -HEXYLE MB) with an IOB value of 0.13.

[0073] According to an embodiment, the total content of component(s) (e) is 0.5 mass% or greater, 1 mass% or greater, 2 mass% or greater or 3 mass% or greater, and 25 mass% or lower, 24 mass% or lower, 23 mass% or lower, 22 mass% or lower, 21 mass% or lower or 20 mass% or lower, based on the total mass of the oil-in-water emulsion. For example, the total content of component(s) (e) rangesfrom 1 to 25 mass%, 2 to 23 mass%, or 3 to 20 mass%, based on the total mass of the oil-in-water emulsion.

[0074] In an embodiment, the content of water (component (f)) ranges from 50 to 90 mass%, 60 to 85 mass%, or 70 to 80 mass% based on the total mass of the oil-in-water emulsion.

[0075] In an embodiment, the oil-in-water emulsion includes components other than components (a) to (f). Examples of such other components include polyhydric alcohols, neutralizers, preservatives, perfumes, surfactants other than those mentioned above, water-soluble polymers, powders, ultraviolet absorbers, saccharides, humectants, lower alcohols, antioxidants, enzymes such as lipases and proteases, refreshing agents, pigments and mixtures thereof.

[0076] In an embodiment, the polyhydric alcohol is a polyhydric alcohol of 1 to 8 or 2 to 5 carbon atoms. For example, the number of hydroxy groups of the polyhydric alcohol is 2 to 4 or 2 to 3. For example, the polyhydric alcohol is a diol or triol. Examples of diols include ethylene glycol, 1 ,2-propylene glycol, 1,3-propylene glycol (propanediol), 1,3-butylene glycol (butylene glycol) and 1,2- pentanediol (pentylene glycol), and mixtures thereof. Glycerin is an example of a triol. Any of these polyhydric alcohols are used alone, or two or more are used in combination.

[0077] In an embodiment, the total content of the polyhydric alcohol(s) is of 1 mass% or greater, 5 mass% or greater or 7 mass% or greater, based on the total mass of the oil-in-water emulsion. In another embodiment, the total content of the polyhydric alcohol(s) ranges from 1 to 30 mass%, 5 to 20 mass% or 7 to 15 mass%, for example.

[0078] In a particular embodiment, the oil-in-water emulsion includes oil globules with diameters (cumulant diameters) of 300 nm or smaller. In particular, the oil globule diameters are preferably 200 nm or smaller or 100 nm or smaller, and 10 nm or larger or 20 nm or larger or in particular 50nm or larger. Oil globule diameters are preferably 10 to 300 nm and more preferably 20 to 200 nm, or even more preferably 50 to 200 nm. The oil globule diameters are determined by dynamic light scattering measurement. The specific method to determine the oil globule diameter by dynamic light scattering measurement is as described in the Examples.

[0079] The pH of the oil-in-water emulsion, according to one embodiment, is 4.0 to 7.0 or 4.5 to 6.5, for example. The pH is also determined by the method described in the Examples.

[0080] The light transmittance of the oil-in-water emulsion at a wavelength of 650 nm, according to one embodiment, is 50% or greater, 60% or greater, 70% or greater or 75% or greater. The light transmittance at a wavelength of 650 nm is also determined by the method described in the Examples.

[0081] The oil-in-water emulsion according to one embodiment can be prepared by the following method, as an example. First, phase Al containing component (a), component (b), component (e) and if necessary other components is prepared at 70 to 80°C. Separately, phase A2containing component (f) and if necessary a polyhydric alcohol is prepared at 65 to 75 °C. Phase A2 is then added to and mixed with phase Al at 65 to 75 °C to obtain phase A.

[0082] Next, phase Bl containing component (f) is prepared at 55 to 65°C, and then added to and mixed with phase A at 55 to 65°C to obtain phase AB 1.

[0083] Next, phase B2 containing component (c), component (d), component (f) and if necessary other components is prepared at 55 to 65°C. Phase B2 is then added to and mixed with phase AB1 at 55 to 65°C to obtain phase AB2. Phase AB2 is then cooled to 40°C or less to obtain an oil-in-water emulsion.

[0084] The oil-in-water emulsion described above has excellent stability and can impart freshness, roundness and softness on skin when applied onto a keratinic material (especially skin). The oil-in-water emulsion is therefore particularly suitable as an oil-in-water emulsion for skin care or a leave-on oil-in-water emulsion.

[0085] Another embodiment of the invention is a cosmetic method for caring for and / or making-up keratinic materials, comprising the application onto keratinic materials, in particular onto skin, of the oil- in-water emulsion described above.Examples

[0086] The present invention will now be explained in greater detail by Examples. This is with the understanding, however, that the invention is not limited to the Examples.

[0087] [Preparation of oil-in-water emulsion]The components listed in Tables 1 to 4 were mixed in the compositional ratios listed in Tables 1 to 4 to prepare oil-in-water emulsions (hereunder also referred to simply as "compositions") for Examples 1 to 10 and Comparative Examples 1 to 9. All of the listedvalues are mass%, unless otherwise specified, “q.s.” refers to the amount which is enough.

[0088] The compositions were prepared in the following manner.1. The components of "Al " were mixed to prepare phase Al at 75 °C. Separately, the components of "A2" were mixed to prepare phase A2 at 70°C. Phase Al and phase A2 were combined at 70°C to obtain phase A.2. The components of "Bl" were heated to 60°C to prepare phase Bl. Phase B 1 was added to and mixed with phase A to obtain phase AB 1.3. The components of "B2" were mixed to prepare phase B2 at 60°C. Phase B2 was added to and mixed with phase AB 1 to obtain phase AB2.4. Phase AB2 was cooled to 40°C or below to obtain oil-in-water emulsion.

[0089] The details for each of the components in the tables are as follows.(a+b): Nonionic surfactantsPolyglyceryl- 10 oleate, sucrose distearate: MIZOAN CLEANEMUL- 7300 (polyglyceryl- 10 oleate HLB: 12.0-13.5, content: 70 mass%, sucrose distearate HLB: 4.5-6.9, content: 30 mass%) Steareth-20: BRU S20-PA MBPolysorbate 20: SP TWEEN 20-LQ (CQ) MBPolyglyceryl- 10 myristate: S-FACE M-1001 MB(c): Anionic surfactantsSodium stearoyl glutamate: AMISOFT HS-11 PF MBSodium methyl stearoyl taurate: NIKKOL SMTGlycerin, hydroxylated lecithin: NIKKOL LECINOL WS 50 PCRNEGATIF MBSodium dilauramidoglutamide lysine and water: PELLICER L-30 SGGlyceryl citrate / lactate / linoleate / oleate: IMWITOR 375(d): PolysaccharidesHydroxyethylcellulose: NATROSOL 250 M PCHydroxypropyl methylcellulose: METOLOSE 90 SH 4000Hydroxypropyl methylcellulose stearoxy ether: SANGELOSE 90 L MBCetyl hydroxyethylcellulose: POLYSURF 67 CSTremella fuciformis polysaccharide: TREMOIST TPXanthan gum: RHODICARE XCGellan gum: KELCOGEL CG LASodium hyaluronate: BASHYAL POUDREPyrus cydonia seed extract, propanediol, pentylene glycol, water:QUINCESEED 2NA(Non-poly saccharide thickeners)Carbomer: CARBOPOL ULTREZ 30Acrylates / C 10-30 alkyl acrylate crosspolymer: CARBOPOL ULTREZ 21

[0090] (e): Oil agentsSqualane (IOB: 0): SQUALANE VEGETAL (exPERHYDROSQUALENE)Caprylic / capric triglyceride (IOB: 0.30): TRI CAPRAT / CAPRYLATGLYCEROL MBCoco-caprylate / caprate (IOB: 0.14): CETIOL LC MB(f): WaterWater: EAU PURIFIEE COSM

[0091] Polyhydric alcoholsGlycerin: GLYCEROL VEGETAL MBButylene glycol: 1,3-BUTYLENE GLYCOL VEGETAL(Other components)NeutralizerPreservative

[0092] [Evaluation]The compositions obtained in the Examples and Comparative Examples were evaluated for pH, transmittance, oil globule diameter, aspect, stability and feel during use (freshness, roundness and softness on skin). The results are shown in Tables 1 to 4. The specific evaluation methods were the following.

[0093] (pH)The pH was determined using an F-51 pH meter by Horiba Co.

[0094] (Transmittance)The transmittance for light at a wavelength of 650 nm was determined using a UV-1900 visible / ultraviolet spectrophotometer (Shimadzu Corp.) and a quartz cell with an optical path length of 5 mm.

[0095] (Oil globule diameter)The diameter of the oil globules was measured using a particle size measuring device (DelsaMaxRCORE: manufactured by Beckman Coulter, Inc.) based on dynamic light scattering. The diameter of the oil globules means the cumulant diameter based on dynamic light scattering. The cumulant diameter is determined based on theassumption that only one particle population is present (monomodal). In the tables, "N / A" means that measurement was not possible due to polydispersity of the oil globule sizes.

[0096] (Aspect)The oil-in-water emulsion was placed in a transparent glass container and the aspect was visually observed on the day after the preparation of the oil-in-water emulsion. In the tables, "Bluish" means that the aspect was blue-white, "Opaque" means cloudy white with virtually no transmission of light, and "Hazy" means a cloudy aspect with low transparency.

[0097] (Stability)The oil-in-water emulsion was placed in a transparent glass container and stored for 2 weeks in an incubator at 50°C or 4°C. After storage it was visually observed and evaluated as having inferior stability if the aspect had changed to non-transparent or deep white (Whitish) or if a transparent liquid was observed at the bottom of the glass container (Separation). The composition was evaluated to have excellent stability (Stable) if there was no change in aspect.

[0098] (Feel during use)The feel during use of each of the oil-in-water emulsions of the Examples and Comparative Examples after application was evaluated by an organoleptic evaluation. The prepared oil-in-water emulsion was applied onto facial skin of persons among an evaluation panel of cosmetic experts, and the degree of freshness, roundness and softness on skin imparted by each composition was evaluated on the following evaluation scale. The "freshness" is the perception of a light sensationduring application. The "roundness" is the sensation of cushioning thickness during application. The term "softness on skin" refers to the softness on the skin after application.A: Very Good B: AdequateC: InadequateD: Lacking

[0099] [Table 1]

[0100] In absence of the combination of components a and b (POLYGLYCERYL- 10 OLEATE, SUCROSE DISTEARATE), the comparative formulations 1, 2 and 3 present features that are not acceptable: lack of freshness, lack of softness, and poor roundness.

[0101] [Table 2]

[0102] In the absence of component c (SODIUM STEAROYL GLUTAMATE or SODIUM METHYL STEAROYL LAURATE), the comparative formulations 4 to 7 present features that are not acceptable in terms of stability at 50°C.

[0103] [Table 3]

[0104] [Table ]

[0105] In the absence of component d (polysaccharide), the comparative formulations 8 and 9 present a poor result in roundness. Further, when the polysaccharide is replaced with a carbomer (formulation 8), thesoftness on the skin decreases and the percentage of transmittance becomes dramatically low.

[0106] [Another formulation example] Another formulation example (cream) of oil-in-water emulsion which exhibits excellent freshness, roundness and softness on skin after application, while also having high stability is a mixture of the components listed in Table 5 below. More specifically, the components of "A", "Bl", "B2", "Cl", and "C2" below were each independently mixed to prepare phase A, phase B 1 , phase B2, phase C 1 , and phase C2, and these phases were sequentially mixed in order to prepare the cream. All of the listed values are mass%, unless otherwise specified. The above-described evaluation results and the viscosity of the cream are also shown in Table 5.

[0107] [Table 5]

Claims

CLAIMS1. An oil-in-water emulsion comprising:(a) a polyglycerol straight-chain fatty acid ester having an HLB value of 12 or greater;(b) a sucrose fatty acid ester having an HLB value of 7 or lower;(c) a fatty acid monoamide -based anionic surfactant;(d) a polysaccharide;(e) an oil agent; and(f) water.

2. The oil-in-water emulsion according to claim 1, wherein the content of component (e) is 1 mass% or greater, preferably in the range of 1 mass% to 25 mass%, especially 3 to 20 mass%, based on the total mass of the oil-in-water emulsion.

3. The oil-in-water emulsion according to claim 1 or 2, which further comprises a polyhydric alcohol.

4. The oil-in-water emulsion according to any one of claims 1 to 3, wherein the Inorganic-Organic Balance (IOB) value of component (e) is 0.1 to 0.15.

5. The oil-in-water emulsion according to claim 4, wherein component (e) comprises an oil having an IOB value of lower than 0.1 and an oil having an IOB value of 0.1 or greater.

6. The oil-in-water emulsion according to any one of claims 1 to 5, wherein component (d) is at least one selected from the group consisting of cellulose derivatives and polysaccharides comprising glucuronic acid and a cyclic aldohexose compound as constituent mono saccharide s .

7. The oil-in-water emulsion according to any one of claims 1 to 6, wherein component (a) comprises polyglyceryl- 10 oleate, component (b) comprises sucrose distearate, component (c) comprises a stearic acid monoamide -based anionic surfactant and component (d) comprises at least one selected from the group consisting of cellulose ethers, hydrophobized cellulose ethers and polysaccharides comprising glucuronic acid and a cyclic aldohexose as constituent mono saccharide s .

8. The oil-in-water emulsion according to any one of claims 1 to 7, wherein the oil-in-water emulsion comprises 0.1 to 10.0% of component (a), 0.1 to 10.0% of component (b), 0.01 to 1.0% of component (c) and 0.01 to 1.0% of component (d), based on the total mass of the oil-in-water emulsion.

9. The oil-in-water emulsion according to any one of claims 1 to 8, wherein the oil-in-water emulsion comprises an oil globule with a cumulant diameter of 300 nm or smaller based on dynamic light scattering.

10. A cosmetic process for caring for and / or making-up keratinic materials, wherein the cosmetic process comprises the application onto keratinic materials, in particular onto skin, of the oil-in-water emulsion according to any one of claims 1 to 9.

11. The cosmetic process according to claim 10, wherein the oil-in- water emulsion provides the keratinic materials on which it is applied with freshness, roundness and softness.

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