Oil-in-water emulsion cosmetics

Abstract

This invention provides an oil-in-water emulsion cosmetic that contains polyglycerin fatty acid esters as an essential ingredient, while also offering high-temperature stability, easy application with minimal effort, a non-sticky, moisturizing feel, and a matte finish. [Solution] The above problem is solved by using polyglycerol fatty acid esters composed of linear fatty acids with 8 to 22 carbon atoms and polyglycerol with an average degree of polymerization of 6 to 20.

Description

Technical Field

[0001] The present invention relates to an oil-in-water emulsified cosmetic.

Background Art

[0002] An oil-in-water emulsified cosmetic has an oil internal phase and a water external phase, and is characterized by a non-greasy after-feel and a moist feeling in use. However, conventional skin care cosmetics have various problems in the feeling of use when applied to the skin, so much research has been conducted focusing on the feeling of use (Patent Document 1). On the other hand, when focusing on the feeling of use, separation and deterioration may occur in a high-temperature environment, and there has been a problem in achieving both high-temperature stability and the feeling of use.

[0003] In recent years, due to the demand for sustainable raw materials, the examination of polyglyceryl fatty acid ester, which is a plant-derived raw material, as a surfactant has been increasing. However, the compatibility between high-temperature stability and the feeling of use of an oil-in-water emulsified cosmetic containing polyglyceryl fatty acid ester has not been sufficiently examined, and there is concern that the high-temperature stability of the oil-in-water emulsified cosmetic may decrease or a sticky feeling of use may be imparted.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide an oil-in-water emulsified cosmetic that contains polyglyceryl fatty acid ester, which is a plant-derived raw material, as an essential component, and achieves both high-temperature stability and a feeling of use that can be stretched with a light force, is non-greasy, moist, and has a matte after-feel.

Means for Solving the Problems

[0006] As a result of diligent research, the inventors have found that an oil-in-water emulsion cosmetic composition using a polyglycerin fatty acid ester composed of a linear fatty acid having 8 to 22 carbon atoms and polyglycerin with a degree of polymerization of 6 to 20 solves the above problem. [Effects of the Invention]

[0007] The oil-in-water emulsion cosmetic of the present invention is stable even in high-temperature environments without separation or viscosity reduction, spreads well when applied, is non-sticky, provides a moist and pleasant feel, and also has a matte finish. [Modes for carrying out the invention]

[0008] The present invention will be described in detail below. The scope of the present invention is not limited to these embodiments, and any modified forms that do not impair the spirit of the invention also belong to the present invention. The "~" in the range notation includes both an upper and lower limit. Unless otherwise specified, all units indicating content are in weight percent.

[0009] The polyglycerol fatty acid ester used in the present invention is an ester composed of a straight-chain fatty acid having 8 to 22 carbon atoms and polyglycerol.

[0010] Examples of linear fatty acids having 8 to 22 carbon atoms according to the present invention include caprylic acid, capric acid, lauric acid, myristic acid, stearic acid, and behenic acid, with stearic acid being preferred. When stearic acid is included as a constituent fatty acid, it is preferable that it is contained in an amount of 50 mol% or more.

[0011] The average degree of polymerization of the polyglycerin constituting the polyglycerin fatty acid ester according to the present invention is 6 to 20, more preferably 8 to 16, and most preferably 10. Here, the average degree of polymerization is the average degree of polymerization (n) of polyglycerin calculated from the hydroxyl value by the end group analysis method. Specifically, it is calculated from the following formulas (1) and (2).

[0012] Molecular weight=74n+18 (1) Hydroxyl value = 56110(n+2) / Molecular weight ... (2)

[0013] In formula (2) above, the hydroxyl value is a numerical value that serves as an indicator of the magnitude of the number of hydroxyl groups contained in polyglycerin, and refers to the number of milligrams of potassium hydroxide required to neutralize the acetic acid necessary to acetylate the free hydroxyl groups contained in 1 g of polyglycerin. The number of milligrams of potassium hydroxide is calculated in accordance with the "Standard Test Methods for Analysis of Fats and Oils, 2003 Edition," compiled by the Japan Oil Chemists' Society.

[0014] Polyglycerol fatty acid esters can be produced by conventionally known esterification reactions. For example, they can be produced by esterifying a fatty acid and polyglycerol in the presence of an alkaline catalyst such as sodium hydroxide. The esterification is carried out until the esterification rate of the polyglycerol fatty acid ester reaches a desired value.

[0015] The esterification rate of the polyglycerin fatty acid ester according to the present invention is preferably 20% or less, and more preferably 10% or less. Here, the esterification rate is the value calculated by the following formula (3), where n is the average degree of polymerization of the polyglycerin calculated from the hydroxyl value, n is the number of hydroxyl groups in the polyglycerin (n+2), and M is the number of moles of fatty acid added to the polyglycerin. The hydroxyl value is the value calculated by the above formula (2).

[0016] Esterification rate (%) = (M / (n+2)) × 100 ... (3)

[0017] The HLB of the polyglycerin fatty acid ester according to the present invention is 15 or less, preferably 11 to 15. The HLB is calculated using the ATLAS method from the saponification value of the ester and the neutralization value of the fatty acid, and is calculated using the following formula (4). The saponification value and neutralization value in formula (4) are measured in accordance with the "Standard Test Methods for Analysis of Oils and Fats, 2003 Edition," compiled by the Japan Oil Chemists' Society.

[0018] HLB = 20 × (1 - saponification value / neutralization value) ... (4)

[0019] Specific examples of the polyglycerin fatty acid ester of the present invention include polyglyceryl-6 stearate, polyglyceryl-10 stearate, and polyglyceryl-10 distearate, with polyglyceryl-10 stearate being particularly preferred. Trade names include MS-5S, S-1001P, and S-1002P (all manufactured by Sakamoto Pharmaceutical Co., Ltd.).

[0020] The solid fat according to the present invention is not particularly limited as long as it is a solid oil or fat at 25°C, and for example, fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, behenic acid, undecylenic acid, 12-hydroxystearic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, erucic acid, docosahexaenoic acid, eicosapentaenoic acid, isohexadecanoic acid, anteisohenicosanic acid, long-chain branched fatty acids, dimer acids, hydrogenated dimer acids, etc. Examples of waxes include lyra wax, carnauba wax, rice wax, wood wax, beeswax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, petrolatum, Fischer-Tropsch wax, polyethylene wax, and ethylene-propylene copolymer; vegetable oils such as cocoa butter, shea butter, and coconut oil; animal oils such as beef tallow, milk fat, horse fat, and egg yolk oil; and animal waxes such as whale wax, lanolin, and orange roughy oil. The content is not particularly limited, but 3 to 15% by weight relative to the total amount of the oil-in-water emulsion cosmetic is preferred.

[0021] The polyglycerol according to the present invention is not particularly limited, but an average degree of polymerization of 2 to 10 is preferable. Specifically, diglycerol (average degree of polymerization 2), polyglycerol-3 (average degree of polymerization 3), polyglycerol-4 (average degree of polymerization 4), polyglycerol-6 (average degree of polymerization 6), polyglycerol-10 (average degree of polymerization 10), etc. can be mentioned. Examples of commercially available products include DIG-S, PGL-S, #310, #500, #750 (all manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.), etc. Also, the content is not particularly limited, but 0.5 to 10% by weight is preferable based on the total amount of the oil-in-water type emulsified cosmetic.

[0022] The water content in the present invention is not particularly limited, but 50 to 75% by weight is preferable.

[0023] Also, the present invention preferably contains a higher alcohol. Examples of the higher alcohol include cetyl alcohol, oleyl alcohol, cetostearyl alcohol, stearyl alcohol, arachyl alcohol, behenyl alcohol, chimyl alcohol, batyl alcohol, etc.

[0024] Also, components used in ordinary cosmetics can be contained as long as the effects of the present invention are not impaired. For example, as the aqueous components, alcohols such as erythritol, glycerin, xylitol, ethanol, dipropylene glycol, sorbitol, trehalose, 1,3-butylene glycol, propylene glycol, 1,2-pentanediol, polyethylene glycol, polyoxyethylene glycerin, polypropylene, polyoxypropylene glyceryl ether, polyoxypropylene diglyceryl ether, polyoxypropylene butyl ether, polyoxyethylene·polyoxypropylene butyl ether, polyoxyethylene methyl glucoside, maltitol, mannitol, etc. can be blended.

[0025] It is also possible to use an oily component other than solid fat in combination. For example, as hydrocarbons, there are liquid paraffin, paraffin, squalane, squalene, ozokerite, pristane, ceresin, petrolatum, microcrystalline wax, etc. As ester oils, there are isotridecyl isononanoate, 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, oleyl oleate, acetoglyceride, 2-heptylundecyl palmitate, glyceryl tri(2-ethylhexanoate), glyceryl triisostearate, cetyl 2-ethylhexenoate, glyceryl tri(caprylic / capric acid), ethylene glycol distearate, N-lauroyl sarcosine, glyceryl triisostearate, diisostearyl malate, ethylene glycol monostearate, etc. As vegetable oils, there are safflower oil, olive oil, castor oil, avocado oil, sesame oil, rose hip oil, meadowfoam oil, persic oil, tea tree oil, mint oil, corn oil, rapeseed oil, sunflower oil, wheat germ oil, linseed oil, cottonseed oil, soybean oil, peanut oil, rice bran oil, etc. As silicone oils, there are cyclopentasiloxane, dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, methylhydrogenpolysiloxane, etc.

[0026] Other components include, for example, inorganic powders such as alumina, silica, fuzzy silica (ultrafine anhydrous silicic acid), titanium mica, fish scale foil, boron nitride, synthetic fluorinated mica, fine particle composite powder, gold, aluminum, and other inorganic powders, as well as powders of these materials that have been hydrophobized by surface treatment, para-aminobenzoic acid-based UV absorbers, anthranilic acid-based UV absorbers, salicylic acid-based UV absorbers, cinnamic acid-based UV absorbers, benzophenone-based UV absorbers, sugar-based UV absorbers, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, and 4-methoxy-4'-t-butyldibene UV absorbers such as zoylmethane, inorganic salts such as hydrochlorides and sulfates of sodium, potassium, calcium, aluminum, zinc, magnesium, etc., hydroxy acids such as acetic acid, lactic acid, malic acid, citric acid, succinic acid, etc., organic salts of polyhydric acids and alkali metals, alkyl sulfates, polyoxyethylene alkyl ether sulfates, N-acyl amino acid salts, alkyl ether carboxylates, fatty acid soaps, alkyl phosphates, polyoxyethylene alkyl ether phosphates, N-acyl taurine salts and other anionic surfactants, betaine acetate type amphoteric surfactants, imidazoly Amphoteric surfactants such as 1-type amphoteric surfactants, alkylamidopropyl betaine-type amphoteric surfactants, alkyl hydroxysulfobetaine-type amphoteric surfactants, alkyl carboxymethyl hydroxyethyl imidazolinium betaine-type amphoteric surfactants, alkyldimethylamine oxide, and other amphoteric surfactants; propylene glycol fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, polyoxyethylene rubitan fatty acid esters, polyoxyethylene rubitan fatty acid esters, polyoxyethylene lanolin, polyoxyethylene lanolin alcohol, polyoxyethylene sorbitan beeswax, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene sterols, polyoxyethylene hydrogenated sterols, polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyethylene glycol fatty acid esters, alkyl glyceryl ethers, alkyl polyglycosides, alkyl alkanolamides and other nonionic surfactants; alkylammonium salts, amidoamines and other cationic surfactants.Lecithin derivatives such as hydrogenated soybean phospholipids and hydroxylated soybean phospholipids, organic low molecular weight powders such as N-acyllysine, natural organic powders such as starch, silk powder, and cellulose powder, synthetic high molecular weight powders such as nylon powder and polyethylene powder, glyceride monolaurate, glyceryl monoundecylenate, glyceryl monomyristate, glyceryl monostearate, glyceryl monoisostearate, glyceryl monooleate, glyceryl distearate, polyglyceryl (diisostearate / polyhydroxystearate / sebacate), decaglyceryl (isostearate / succinate), sorbitan monolaurate, sorbitan monooleate This product can contain sorbitan fatty acid esters such as tannin, sorbitan sesquioleate, and sorbitan trioleate; powder dispersants such as polyhydroxystearic acid, castor oil fatty acid condensate, and 1,2-hydroxystearic acid condensate; chelating agents such as edetate, hydroxyethanediphosphate, polyphosphate, and gluconic acid; preservatives such as benzoate, photosensitizer, parabens, phenoxyethanol, salicylic acid, sorbic acid, and isopropylmethylphenol; whitening agents such as arbutin, ellagic acid, kojic acid, and ascorbate derivatives; vitamins, amino acids, glycyrrhizic acid derivatives, plant extracts, fragrances, essential oils, and pH adjusters.

[0027] Examples of cosmetics of the present invention include skincare cosmetics such as cleansing cream, cleansing milk, cleansing lotion, cleansing liquid, facial cleansing cream, facial cleansing foam, massage cream, cold cream, skin cream, skin gel, emulsion, lotion, mask, beauty serum, and aftershave lotion; body care cosmetics such as sunscreen, body shampoo, soap, body lotion, body cream, bath additive, and hand cream; makeup cosmetics such as foundation, makeup base, eyeshadow, eyeliner, mascara, blush, face powder, and eyebrow pencil; and hair cosmetics such as hair shampoo, hair rinse, conditioner, treatment, hair liquid, hair tonic, hair lotion, hair cream, hair dye, and hair styling products. [Examples]

[0028] The invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0029] <Examples 1-4, Comparative Examples 1-3> Oil-in-water emulsions were prepared to a total volume of 200 g using the formulations shown in Table 1. Phases A and B were weighed into beakers and heated to 80°C in a water bath until homogenized. Using a homomixer (PRIMIX 2.5 type), phase A was added to phase B over 3 minutes at a rotation speed of 5000 rpm while maintaining a temperature of 75°C. The resulting mixture was homogenized over 4 minutes at a rotation speed of 5000 rpm. The emulsion was cooled to 30°C on a water bath while being stirred by hand.

[0030] [High temperature stability] The oil-in-water emulsion cosmetic compositions of Examples 1-4 and Comparative Examples 1-3 were visually inspected after being stored at 50°C for one month and evaluated according to the following criteria. The results are shown in Table 1. (Evaluation Criteria) ○: No separation of external appearance △: No separation in appearance, but creaming is present. ×: Separation was observed in the upper or lower layers.

[0031] [Sensory evaluation] The oil-in-water emulsion cosmetics of Examples 1-4 and Comparative Examples 1-3 were applied to the inner arms of five healthy male and female panelists, and sensory evaluations were conducted regarding spreadability, non-stickiness, moisturizing effect, and matte finish. Samples with good spreadability, non-stickiness, moisturizing effect, and matte finish were assigned a score of 5 for each category, and the average score of the five panelists was calculated and evaluated according to the following criteria. The results are shown in Table 1. (Evaluation Criteria) ◎: 4.0 points or higher ○: 3.0 points or higher, less than 4.0 points △: 2.0 points or more, less than 3.0 points ×: Less than 2.0 points

[0032] [Table 1]

[0033] The oil-in-water emulsion cosmetic composition in the example was stable with no separation at high temperatures, and exhibited good spreadability, non-stickiness, moisturizing, and matte texture, fully meeting the evaluation criteria. On the other hand, the comparative example composition showed unsatisfactory results in terms of high-temperature stability and texture.

Claims

1. An oil-in-water emulsion cosmetic characterized by containing a polyglycerin fatty acid ester composed of a linear fatty acid having 8 to 22 carbon atoms and polyglycerin with an average degree of polymerization of 6 to 20.

2. Furthermore, the oil-in-water emulsion cosmetic composition according to claim 1 is characterized by containing solid fat and polyglycerin.

3. The oil-in-water emulsion cosmetic according to claim 1, characterized in that the constituent fatty acids of the polyglycerin fatty acid ester include stearic acid.

4. The oil-in-water emulsion cosmetic according to claim 1, characterized in that the polyglycerin fatty acid ester is polyglyceryl-10 stearate.

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