Solubilizer composition and cosmetic

Abstract

The present invention provides a solubilizer composition that has excellent solubilizing properties for oil-soluble components, can easily solubilize oil-soluble components into a transparent or microemulsion-like state with a small amount of incorporation, has an excellent feel when used, and has good temperature stability over time; and provides a cosmetic preparation containing the solubilizer composition. [Solution] The solubilizer composition contains a polyglycerol fatty acid ester, which is an ester of (a) a polyglycerol having an average degree of polymerization in the range of 15 to 50; (b) at least one selected from monocarboxylic acids having a carbon number in the range of 8 to 18; and (c) at least one selected from dicarboxylic acids having a carbon number in the range of 6 to 20, wherein the esterification rate of all constituent fatty acids {(b) + (c)} relative to (a) is 30% or less, and the molar ratio of {(a) + (b)}:(c) is in the range of 1:0.01 to 1:0.1.

Description

[Technical Field]

[0001] The present invention relates to a solubilizer composition that solubilizes oil-soluble components used in cosmetics and the like, and to a cosmetic containing the solubilizer composition. [Background technology]

[0002] In cosmetics, quasi-drugs, topical skin preparations, and the like that have a transparent to translucent appearance, oil-soluble ingredients, which are active ingredients that are poorly soluble in water, such as oils such as fragrances, essential oils, vegetable oils, hydrocarbon oils, and ester oils, and fat-soluble vitamins, are usually solubilized using a solubilizer. Examples of such solubilizers include nonionic surfactants with high hydrophilicity, and polyoxyethylene derivatives have been particularly used. However, polyoxyethylene surfactants have problems such as residual ethylene glycol and skin irritation caused by the residual ethylene glycol, and therefore the cosmetics market has been looking for solubilizers that are safe and cause little skin irritation.

[0003] On the other hand, polyglycerol fatty acid ester-type nonionic surfactants are useful as safe solubilizing agents for cosmetics, but their solubilizing performance is not necessarily sufficient.

[0004] Therefore, methods for solubilizing oil-soluble components using polyglycerol fatty acid esters have been investigated. For example, a method using a condensed polyglycerol ricinoleate in combination with a polyglycerol laurate (see Patent Document 1) and a method using a medium-chain fatty acid polyglycerol in combination with a long-chain fatty acid polyglycerol (see Patent Document 2) have been proposed, but these methods alone have not yielded compositions with a transparent appearance.

[0005] Other methods that have been proposed include a solubilization method using a polyglycerol fatty acid ester obtained by removing glycerol and diglycerol from the raw material polyglycerol (see Patent Document 3), and a solubilization method using a polyglycerol fatty acid ester obtained by removing the content of triglycerol or lower polyglycerols to less than 10% (see Patent Document 4). However, these methods require the incorporation of a large amount of polyglycerol fatty acid ester, and the resulting cosmetics have issues with usability when applied to the skin, such as stickiness after application. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-268950 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-044780 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-100574 [Patent Document 4] Japanese Patent Application Publication No. 2018-070529 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a solubilizer composition that has excellent performance in solubilizing oil-soluble ingredients, can easily solubilize oil-soluble ingredients into a transparent to microemulsion-like state with the incorporation of a small amount, has an excellent feel when used, and has good temperature stability over time, and to provide a cosmetic preparation containing the solubilizer composition. [Means for solving the problem]

[0008] The present invention provides a solubilizer composition comprising a polyglycerol fatty acid ester, which is an ester of (a) a polyglycerol having an average degree of polymerization in the range of 15 to 50; (b) at least one selected from monocarboxylic acids having a carbon number in the range of 8 to 18; and (c) at least one selected from dicarboxylic acids having a carbon number in the range of 6 to 20, wherein the esterification rate of all constituent fatty acids {(b) + (c)} relative to (a) is 30% or less, and the molar ratio of {(a) + (b)}:(c) is in the range of 1:0.01 to 1:0.1.

[0009] In the solubilizer composition, the (b) monocarboxylic acid having 8 to 18 carbon atoms is preferably at least one selected from caprylic acid, capric acid, lauric acid, coconut oil fatty acid, oleic acid, and isostearic acid.

[0010] In the solubilizer composition, the (c) dicarboxylic acid having 6 to 20 carbon atoms is preferably at least one selected from adipic acid, sebacic acid, dodecanedioic acid, and isoeicosanedioic acid.

[0011] The viscosity of the solubilizer composition at 80°C is preferably 10,000 mPa·s or less.

[0012] The present invention is a cosmetic preparation containing the solubilizer composition. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a solubilizer composition that has excellent performance in solubilizing oil-soluble components, can easily solubilize oil-soluble components into a transparent or microemulsion-like state with the incorporation of a small amount, has an excellent feel when used, and has good temperature stability over time, and a cosmetic preparation containing the solubilizer composition. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes an embodiment of the present invention. The embodiment is an example of implementing the present invention, and the present invention is not limited to the embodiment.

[0015] <Solubilizer composition> The solubilizer composition according to this embodiment contains a polyglycerol fatty acid ester, which is an ester of (a) a polyglycerol having an average degree of polymerization in the range of 15 to 50; (b) at least one selected from monocarboxylic acids having a carbon number in the range of 8 to 18; and (c) at least one selected from dicarboxylic acids having a carbon number in the range of 6 to 20, wherein the esterification rate of all constituent fatty acids {(b) + (c)} relative to (a) is 30% or less, and the molar ratio of {(a) + (b)}:(c) is in the range of 1:0.01 to 1:0.1.

[0016] As a result of extensive research, the present inventors have found that polyglycerol fatty acid esters, whose constituent fatty acids are monocarboxylic acids and dicarboxylic acids having chain lengths within a specific range, have excellent solubilizing properties for oil-soluble ingredients, can easily solubilize oil-soluble ingredients into a transparent to microemulsion-like state with a small amount of incorporation, have an excellent feel when used, and have good temperature stability over time. The solubilizer composition according to this embodiment has liquid properties, yet is easy to design its structure, is highly productive, and cosmetics containing this composition have a transparent to microemulsion-like appearance, have an excellent feel when used, and are stable over time.

[0017] The polyglycerin having an average degree of polymerization in the range of 15 to 50 that constitutes the polyglycerin fatty acid ester in the solubilizer composition according to this embodiment functions as a hydrophilic group in the solubilizer composition, which is a nonionic surfactant, and is a component that plays a major role in forming micelles that utilize hydrogen bonding by hydroxyl groups to dissolve solubilized substances, such as oil-soluble components used in cosmetics, in water.

[0018] The average degree of polymerization of polyglycerol is in the range of 15 to 50, and preferably in the range of 20 to 40. If the average degree of polymerization of polyglycerol is less than 15, the hydrophilicity is insufficient, and if it exceeds 50, the viscosity becomes high, making it difficult to charge into a reactor.

[0019] The fatty acids constituting the polyglycerol fatty acid ester in the solubilizer composition according to this embodiment include at least one selected from monocarboxylic acids having 8 to 18 carbon atoms and at least one selected from dicarboxylic acids having 6 to 20 carbon atoms.

[0020] The monocarboxylic acid having 8 to 18 carbon atoms functions as a lipophilic group of the solubilizer composition, which is a nonionic surfactant, and is a component that is compatible with the substance to be solubilized to form micelles.

[0021] Examples of monocarboxylic acids having 8 to 18 carbon atoms include linear saturated fatty acids such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid; linear unsaturated fatty acids such as oleic acid; and branched fatty acids such as ethylhexanoic acid, isopalmitic acid, and isostearic acid. Monocarboxylic acids having 8 to 18 carbon atoms may also be mixed fatty acids such as palm kernel oil fatty acids and coconut oil fatty acids. Mixed fatty acids preferably have a relatively short chain length. The term "8 to 18 carbon atoms" includes the number of carbon atoms in the carboxyl group. Monocarboxylic acids having less than 8 carbon atoms have a short carbon chain length when considered as a lipophilic group, resulting in poor compatibility with oil-soluble components. Monocarboxylic acids having more than 18 carbon atoms are not preferred as solubilizers due to their long carbon chain length, which reduces water solubility. The monocarboxylic acid having 8 to 18 carbon atoms is preferably at least one selected from caprylic acid, capric acid, lauric acid, coconut oil fatty acid, oleic acid, and isostearic acid, as the solubilized composition is preferably in a liquid to paste form at 20° C. The monocarboxylic acid having 8 to 18 carbon atoms may be used alone or in combination of two or more of these.

[0022] Dicarboxylic acids having 6 to 20 carbon atoms are components that increase the molecular weight of polyglycerin, which is the hydrophilic group of the solubilizer composition, a nonionic surfactant, and act as lipophilic groups that are responsible for the formation of oligomers and compatibility with the solubilized substance.

[0023] Examples of dicarboxylic acids having 6 to 20 carbon atoms include adipic acid, sebacic acid, decanedioic acid, dodecanedioic acid, eicosane diacid, isodecanedioic acid, isododecanedioic acid, and isoeicosane diacid. Because the dicarboxylic acid having 6 to 20 carbon atoms is preferably a liquid or paste-like composition at 20°C, it is preferable to use at least one selected from adipic acid, sebacic acid, dodecanedioic acid, and isoeicosane diacid. Note that "6 to 20 carbon atoms" includes the number of carbon atoms in the carboxyl group. Dicarboxylic acids having fewer than 6 carbon atoms tend to increase in molecular weight due to their high reactivity, making them difficult to remove from the reactor and insoluble in the extraction solvent. Dicarboxylic acids having more than 20 carbon atoms may produce solid reaction products, causing cosmetics using them as solubilizers to solidify at low temperatures. Dicarboxylic acids having 6 to 20 carbon atoms can be used alone or in combination.

[0024] The esterification rate of all constituent fatty acids (monocarboxylic acids having 8 to 18 carbon atoms + dicarboxylic acids having 6 to 20 carbon atoms) relative to polyglycerin in the polyglycerol fatty acid ester is 30% or less, preferably in the range of 10% to 30%. If the esterification rate of all constituent fatty acids relative to polyglycerin exceeds 30%, the polyglycerol fatty acid ester may become too high in molecular weight to be discharged from the reactor, or the polarity may decrease, making it impossible to obtain satisfactory solubilization ability.

[0025] In the polyglycerol fatty acid ester, the molar ratio of (polyglycerol having an average degree of polymerization of 15 to 50 + monocarboxylic acid having 8 to 18 carbon atoms): dicarboxylic acid having 6 to 20 carbon atoms is in the range of 1:0.01 to 1:0.1, preferably 1:0.03 to 0.09. If the molar ratio of (polyglycerol having an average degree of polymerization of 15 to 50 + monocarboxylic acid having 8 to 18 carbon atoms): dicarboxylic acid having 6 to 20 carbon atoms in the polyglycerol fatty acid ester is less than 1:0.01, the polyglycerol fatty acid ester cannot be made high molecular weight and has low polarity, resulting in failure to obtain solubilizing ability. Furthermore, if the molar ratio of (polyglycerol having an average degree of polymerization in the range of 15 to 50 + monocarboxylic acid having 8 to 18 carbon atoms): dicarboxylic acid having 6 to 20 carbon atoms in the polyglycerol fatty acid ester is greater than 1:0.1, the polyglycerol fatty acid ester will have a higher molecular weight and become a high polymer, which may make it difficult to discharge from the reactor.

[0026] The method for producing polyglycerin, which is a raw material for the polyglycerin fatty acid ester constituting the solubilizer composition according to this embodiment, is not particularly limited. Examples of methods for preparing polyglycerin include dehydration polymerization of glycerin and ring-opening polymerization using a glycerin analogue such as glycidol or epichlorohydrin. The obtained polyglycerin may also be purified by distillation or column chromatography.

[0027] The polyglycerol fatty acid ester in the solubilizer composition according to this embodiment is obtained by an esterification reaction between a monocarboxylic acid having 8 to 18 carbon atoms, a dicarboxylic acid having 6 to 20 carbon atoms, and polyglycerol, regardless of the synthesis method, and may be further purified according to a known method. For example, it can be produced by adding an acid catalyst to the starting fatty acid and polyglycerol, and carrying out an esterification reaction at normal pressure or reduced pressure at a temperature in the range of 50 to 250°C, for example, 200°C. The origin of the starting fatty acid is not particularly limited.

[0028] The viscosity of the solubilizer composition according to this embodiment at 80°C as measured by a Brookfield viscometer is preferably 10,000 mPa·s or less, and more preferably 9,000 mPa·s or less. If the viscosity of the solubilizer composition at 80°C as measured by a Brookfield viscometer exceeds 10,000 mPa·s, it becomes difficult to discharge the composition from the reactor or to filter it, and productivity may not be ensured. The lower limit of the viscosity of the solubilizer at 80°C as measured by a Brookfield viscometer is preferably as low as possible, and is not particularly limited, but is, for example, 5,000 mPa·s.

[0029] The polyglycerol fatty acid ester in the solubilizer composition according to the present embodiment can be various types of ester compounds depending on the purpose of its development. That is, an ester having the desired surfactant properties can be obtained by selecting a monocarboxylic acid type, combining two or more different monocarboxylic acids, selecting a dicarboxylic acid type, or combining two or more different dicarboxylic acids.

[0030] The viscosity and polarity of the solubilizer composition according to this embodiment can be adjusted as desired by appropriately selecting the raw materials, and it is possible to provide a cosmetic preparation that is excellent in stability and usability in accordance with the substance to be solubilized.

[0031] The solubilizer composition according to this embodiment may contain other components such as an antioxidant and a preservative in addition to the polyglycerol fatty acid ester.

[0032] When the solubilizer composition according to this embodiment contains components other than the polyglycerol fatty acid ester, the content of the other components is, for example, in the range of 0.1 to 10.0% by mass relative to the amount of the solubilizer composition.

[0033] The solubilizer composition according to this embodiment can be suitably used in the field of cosmetics, and in particular can be suitably used in transparent to microemulsion-like liquid cosmetics in which oil-soluble components are solubilized and dispersed in an aqueous solution.

[0034] The applications of cosmetics in which the solubilizer composition according to the present embodiment is used are not particularly limited, and the solubilizer composition can be used as a nonionic surfactant in skin care cosmetics such as lotions, serums, creams, and emulsions; UV protection cosmetics such as UV mists, UV gels, and UV creams; cleansing cosmetics such as cleansing oils, cleansing liquids, cleansing waters, cleansing gels, and cleansing creams; bath cosmetics such as bath oils and bath milks; hair care cosmetics such as hair mists, hair waxes, hair balms, and hair conditioners; cleansing agents such as hair shampoos, body shampoos, and facial washes; and fragrance cosmetics such as perfumes.

[0035] <Cosmetics> The solubilizer composition according to this embodiment is a solubilizer for solubilizing an oil-soluble component in water, and a cosmetic containing this solubilizer composition will be described below. The cosmetic according to this embodiment is a cosmetic containing the solubilizer composition. The cosmetic according to this embodiment is, for example, a cosmetic containing the solubilizer composition, an oil-soluble component, and water.

[0036] Examples of cosmetics according to this embodiment include skin care cosmetics such as lotions, serums, creams, and emulsions; UV protective cosmetics such as UV mists, UV gels, and UV creams; cleansing cosmetics such as cleansing oils, cleansing liquids, cleansing waters, cleansing gels, and cleansing creams; bath cosmetics such as bath oils and bath milks; hair care cosmetics such as hair mists, hair waxes, hair balms, and hair conditioners; and cleansing products such as hair shampoos, body shampoos, and facial cleansers. Among these, the cosmetics are particularly suitable for skin care cosmetics such as lotions and serums; UV protective cosmetics such as UV mists; hair care cosmetics such as hair mists used to straighten hair; and fragrance cosmetics such as perfumes. These cosmetics and cleansing products are in the form of solubilized and dispersed in water with a transparent or microemulsion-like appearance, using oil-soluble components that are insoluble or difficult to dissolve in aqueous components, such as hydrocarbon oils, ester oils, animal and vegetable oils, fragrances, essential oils, and UV absorbers, as solubilized substances.

[0037] The amount of the solubilizer composition in cosmetics such as lotions and hair mists according to this embodiment is not particularly limited, but is, for example, about 0.01 to 20% by mass, preferably in the range of 0.05 to 10% by mass, relative to the mass of the cosmetic. If the amount of the solubilizer composition in the solubilizer composition is less than 0.01% by mass relative to the mass of the cosmetic, oil-soluble ingredients such as oils and fragrances may not be solubilized in water, and an oil film or oil droplets may form on the surface of the cosmetic. If the amount exceeds 20% by mass, a transparent and stable formulation may be easily obtained, but the cosmetic may feel sticky when used.

[0038] The oil-soluble component to be solubilized in the cosmetics such as lotion and hair mist according to this embodiment is not particularly limited as long as it is used as an oil-soluble component for cosmetics, and examples thereof include orange oil, rosemary oil, lemon oil, rose oil, lavender oil, jasmine oil, peppermint oil, bergamot oil, animal and plant fragrances such as limonene, musk, and agave, synthetic fragrances such as limonene, linalool, geraniol, menthol, and citral, compound fragrances obtained by compounding animal and plant fragrances and synthetic fragrances according to the purpose, fat-soluble vitamins such as vitamin A and vitamin B, isopropyl myristate, isopropyl palmitate, cetyl ethylhexanoate, isocetyl ethylhexanoate, isononyl isononanoate, isotope isononanoate, and the like. Ester oils such as propylene glycol tridecyl, caprylic / capric triglyceride, and propylene glycol laurate; hydrocarbon oils such as liquid paraffin, liquid isoparaffin, and squalane; animal and vegetable oils such as orange roughy oil, liquid lanolin, jojoba oil, soybean oil, olive oil, almond oil, meadowfoam oil, corn oil, and castor oil; acyl amino acid ester oils such as hexyldecyl myristoylmethylaminopropionate, isopropyl lauroyl sarcosine, dihexyldecyl lauroyl glutamate, and di(phytosteryl / octyldodecyl) lauroyl glutamate; phytosterols, and the like, can be used in combination as long as the effect of the solubilizer composition according to this embodiment as a nonionic surfactant is not impaired.

[0039] The content of oil-soluble components in cosmetics such as lotions and hair mists according to this embodiment is not particularly limited, but is, for example, in the range of 0 to 10% by mass, and preferably in the range of 0 to 5% by mass.

[0040] The quantitative relationship between the solubilizer composition according to this embodiment and the oil-soluble component is not particularly limited, but from the viewpoint of cost, it is preferable to use a solubilizer composition in an amount by mass that is 5 times or less the amount of the oil-soluble component.

[0041] Cosmetics such as lotions and hair mists according to this embodiment contain, in addition to the solubilizer composition and oil-soluble component, nonionic surfactants other than the solubilizer composition, such as polyglycerin fatty acid esters such as polyglyceryl-10 laurate, polyglyceryl-10 isostearate, and polyglyceryl-20 decacaprate, polyoxyalkylene alkyl ethers such as ceteth-20, isoceteth-25, octyldodeceth-20, and PPG-2-deceth-12, polyoxyethylene sorbitan fatty acid esters such as polysorbate 80, and PEG-40 water. Any nonionic surfactant that is commonly used can be used in combination as long as it does not impair the effects of the solubilizer composition according to this embodiment, such as polyoxyethylene hydrogenated castor oils and derivatives thereof, such as hydrogenated castor oil, PEG-60 hydrogenated castor oil, and PEG-50 hydrogenated castor oil isostearate, polyoxyethylene glycerin fatty acid esters, such as PEG-50 glyceryl isostearate, and pyroglutamic acid derivatives, such as PEG-30 hydrogenated castor oil PCA isostearate and glycereth-25 PCA isostearate.

[0042] Cosmetics such as lotions and hair mists according to this embodiment may contain an ionic surfactant within a range that does not impair the effects of the solubilizer composition according to this embodiment. The type of ionic surfactant is not particularly limited, and can be appropriately selected from anionic surfactants, cationic surfactants, and amphoteric surfactants. Examples of ionic surfactants include N-long-chain acyl amino acid salts such as N-long-chain acyl acidic amino acid salts and N-long-chain acyl neutral amino acid salts, N-long-chain fatty acid acyl-N-methyl taurine salts, alkyl sulfates and alkylene oxide adducts, fatty acid amide ether sulfates, metal salts and weak bases of fatty acids, sulfosuccinic acid surfactants, alkyl phosphates and alkylene oxide adducts thereof, anionic surfactants such as alkyl ether carboxylic acids, aliphatic amine salts such as alkylammonium chlorides and dialkylammonium chlorides, quaternary ammonium salts thereof, aromatic quaternary ammonium salts such as benzalkonium, cationic surfactants such as fatty acid acyl arginine esters, and various surfactants such as betaine surfactants such as carboxybetaine, aminocarboxylic acid surfactants, and amphoteric surfactants such as imidazoline amphoteric surfactants.

[0043] Cosmetics such as lotions and hair mists according to this embodiment may contain a moisturizer as an aqueous phase component to the extent that the effect of the solubilizer composition according to this embodiment is not impaired. Examples of moisturizers include polyhydric alcohols such as dipropylene glycol, propylene glycol, 1,3-butylene glycol, propanediol, and glycerin, sugars such as sorbitol and maltitol, amino acids such as glycine, alanine, serine, threonine, arginine, glutamic acid, aspartic acid, leucine, and valine, polyamino acids including polyglutamic acid and polyaspartic acid and salts thereof, polyethylene glycol, polyglycerin, gum arabic, alginates, xanthan gum, hyaluronic acid, hyaluronates, chitin, water-soluble chitin, carboxyvinyl polymers, carboxymethylcellulose, and hydroxyethylcellulose, and lower alcohols such as ethanol and propanol.

[0044] In addition to surfactants and moisturizers, cosmetics such as lotions and hair mists according to this embodiment can further contain ingredients commonly used in cosmetics and pharmaceuticals, provided that the effects of the solubilizer composition according to this embodiment are not impaired. For example, additives such as ultraviolet absorbers, antioxidants, fragrances, colorants, chelating agents, cooling agents, plant extracts, vitamins, pH adjusters, and preservatives can be appropriately added depending on the intended use.

[0045] The method for preparing the cosmetic preparations such as lotion and hair mist according to this embodiment is not particularly limited, and they can be prepared using a conventional method. For example, the cosmetic preparations can be easily prepared by dissolving the solubilizer composition according to this embodiment and a solubilized substance such as an essential oil, a fragrance, or an ester oil in ethanol or the like, and then diluting the solution with purified water or the like.

[0046] The present specification includes the following embodiments. (1) A polyglycerol fatty acid ester is an ester of (a) a polyglycerol having an average degree of polymerization in the range of 15 to 50; (b) at least one selected from monocarboxylic acids having a carbon number in the range of 8 to 18; and (c) at least one selected from dicarboxylic acids having a carbon number in the range of 6 to 20; A solubilizer composition in which the esterification rate of all constituent fatty acids {(b) + (c)} relative to (a) is 30% or less, and the molar ratio of {(a) + (b)}:(c) is in the range of 1:0.01 to 1:0.1.

[0047] (2) The solubilizer composition according to (1), A solubilizer composition, wherein the (b) monocarboxylic acid having 8 to 18 carbon atoms is at least one selected from caprylic acid, capric acid, lauric acid, coconut oil fatty acid, oleic acid, and isostearic acid.

[0048] (3) The solubilizer composition according to (1) or (2), A solubilizer composition, wherein the (c) dicarboxylic acid having 6 to 20 carbon atoms is at least one selected from adipic acid, sebacic acid, dodecanedioic acid, and isoeicosanedioic acid.

[0049] (4) The solubilizer composition according to any one of (1) to (3), The solubilizer composition has a viscosity of 10,000 mPa·s or less at 80°C.

[0050] (5) A cosmetic comprising the solubilizer composition according to any one of (1) to (4). [Example]

[0051] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the examples, "parts" means "parts by mass" and "%" means "% by mass" unless otherwise specified.

[0052] The average degree of polymerization of polyglycerol can be calculated from the hydroxyl value by the following formula (i): The hydroxyl value in formula (i) can be measured in accordance with the "Standard Testing Methods for the Analysis of Fats, Oils and Related Compounds" (established by the Japan Oil Chemists' Association). Average degree of polymerization=(112.2×10 3 -18 × hydroxyl value) / (74 × hydroxyl value - 56.1 × 10 3 )···(i)

[0053] The average molecular weight (Mn) of polyglycerol with an average degree of polymerization of 20 was confirmed by a matrix-assisted laser desorption / ionization time-of-flight mass spectrometer (Shimadzu Corporation, MALDI-8030).

[0054] The esterification rate of the obtained polyglycerol fatty acid ester was determined by calculation based on the hydroxyl value of the polyglycerol used in the preparation of the polyglycerol fatty acid ester and the number of moles of the monocarboxylic acid having 8 to 18 carbon atoms and the dicarboxylic acid having 6 to 20 carbon atoms. The molar ratio of the monocarboxylic acid having 8 to 18 carbon atoms to all fatty acids in the obtained polyglycerol fatty acid ester was determined by calculation based on the number of moles of the monocarboxylic acid having 8 to 18 carbon atoms and the dicarboxylic acid having 6 to 20 carbon atoms used in the preparation of the polyglycerol fatty acid ester.

[0055] The esterification rate of polyglycerol fatty acid ester can be calculated by the following formula (ii), where n is the average degree of polymerization of polyglycerol, n+2 is the number of hydroxyl groups in this polyglycerol, and M is the number of moles of fatty acid added to 1 mole of polyglycerol. Esterification rate (%) = (M / (n+2)) × 100 (ii)

[0056] [Preparation of polyglycerol fatty acid esters] <Synthesis Example 1> 272.8 g of polyglycerol (average molecular weight: 1516) with an average degree of polymerization of 20, 113.6 g (0.66 mol) of capric acid with 10 carbon atoms, and 13.6 g (0.067 mol) of sebacic acid with 10 carbon atoms were placed in a reaction vessel, and 0.12 g of sodium hydroxide was added. After that, the reaction was carried out at 250°C for 4 hours in a nitrogen stream, yielding 330 g of "penta(capric acid / sebacic acid)polyglyceryl-20" with an esterification rate (ES) of 21% and an {(a) + (b)}:(c) ratio of 1:0.08.

[0057] <Synthesis Example 2> 243.2 g of polyglycerol with an average degree of polymerization of 20, 148 g (0.71 mol) of coconut oil fatty acid, and 8.8 g (0.060 mol) of adipic acid with a carbon number of 6 were placed in a reaction vessel, and 0.2 g of sodium hydroxide was added. After that, the reaction was carried out at 250°C for 3 hours in a nitrogen atmosphere, yielding 332 g of "penta(coconut oil fatty acid / adipic acid)polyglyceryl-20" with an esterification rate of 24% and an {(a) + (b)}:(c) ratio of 1:0.07.

[0058] <Synthesis Example 3> 257.2 g of polyglycerol with an average degree of polymerization of 20, 130.4 g (0.62 mol) of coconut oil fatty acid, and 12.4 g (0.061 mol) of sebacic acid with a carbon number of 10 were placed in a reaction vessel, and 0.20 g of sodium hydroxide was added. After that, the reaction was carried out at 250°C for 3 hours in a nitrogen atmosphere, yielding 320 g of "penta(coconut oil fatty acid / sebacic acid)polyglyceryl-20" with an esterification rate of 21% and a {(a) + (b)}:(c) ratio of 1:0.08.

[0059] <Synthesis Example 4> 241.2 g of polyglycerol with an average degree of polymerization of 20, 146.8 g (0.70 mol) of coconut oil fatty acid, and 12 g (0.059 mol) of sebacic acid with a carbon number of 10 were placed in a reaction vessel, and 0.2 g of sodium hydroxide was added. After that, the reaction was carried out in a nitrogen atmosphere at 250°C for 3 hours, yielding 330 g of "hexa(coconut oil fatty acid / sebacic acid)polyglyceryl-20" with an esterification rate of 25% and a {(a) + (b)}:(c) ratio of 1:0.07.

[0060] <Synthesis Example 5> 257.2 g of polyglycerol with an average degree of polymerization of 20, 130.4 g (0.62 mol) of coconut oil fatty acid, and 12.4 g (0.061 mol) of isosebacic acid with 10 carbon atoms were placed in a reaction vessel, and 0.2 g of sodium hydroxide was added. After that, the reaction was carried out at 250°C for 5 hours in a nitrogen stream, yielding 320 g of "penta(coconut oil fatty acid / isosebacic acid)polyglyceryl-20" with an esterification rate of 20% and a {(a) + (b)}:(c) ratio of 1:0.08.

[0061] <Synthesis Example 6> 256 g of polyglycerol with an average degree of polymerization of 20, 129.6 g (0.62 mol) of coconut oil fatty acids, and 14.4 g (0.063 mol) of isododecanedioic acid with 12 carbon atoms were placed in a reaction vessel, and 0.20 g of sodium hydroxide was added. After that, the reaction was carried out at 250°C for 5 hours in a nitrogen atmosphere, yielding 330 g of "penta(coconut oil fatty acids / isododecanedioic acid) polyglyceryl-20" with an esterification rate of 20% and a {(a) + (b)}:(c) ratio of 1:0.08.

[0062] <Synthesis Example 7> 251.6 g of polyglycerol with an average degree of polymerization of 20, 127.6 g (0.61 mol) of coconut oil fatty acid, and 20.8 g (0.061 mol) of isoeicosanedioic acid with 20 carbon atoms were placed in a reaction vessel, and 0.2 g of sodium hydroxide was added. After that, the reaction was carried out at 250°C for 4.5 hours under a nitrogen atmosphere, yielding 328 g of "penta(coconut oil fatty acid / isoeicosanedioic acid) polyglyceryl-20" with an esterification rate of 21% and a {(a) + (b)}:(c) ratio of 1:0.08.

[0063] <Synthesis Example 8> 291.2 g of polyglycerol having an average degree of polymerization of 40, 101.6 g (0.70 mol) of caprylic acid having 8 carbon atoms, and 7.2 g (0.036 mol) of sebacic acid having 10 carbon atoms were placed in a reaction vessel, and 0.20 g of sodium hydroxide was added. After that, the reaction was carried out in a nitrogen atmosphere at 250°C for 4 hours, yielding 320 g of "nonat(caprylic acid / sebacic acid) polyglyceryl-40" with an esterification rate of 20% and an {(a) + (b)}:(c) ratio of 1:0.04.

[0064] <Synthesis Example 9> 244.4 g of polyglycerol with an average degree of polymerization of 20, 68.4 g (0.47 mol) of caprylic acid with 8 carbon atoms, 66.8 g (0.24 mol) of oleic acid, an unsaturated fatty acid with 18 carbon atoms, and 20.4 g (0.060 mol) of isoeicosanedioic acid with 20 carbon atoms were placed in a reaction vessel, and 0.2 g of sodium hydroxide was added. After that, the reaction was carried out at 250°C for 3 hours in a nitrogen stream, yielding 330 g of "penta(caprylic acid / oleic acid / isoeicosanedioic acid) polyglyceryl-20" with an esterification rate of 24% and an {(a) + (b)}:(c) ratio of 1:0.07.

[0065] <Synthesis Example 10> 265.6 g of polyglycerol with an average degree of polymerization of 20 and 134.4 g (0.64 mol) of coconut oil fatty acids were placed in a reaction vessel, and 0.16 g of sodium hydroxide was added. The reaction was then carried out in a nitrogen atmosphere at 250°C for 4 hours, yielding 330 g of "tetracoconut oil fatty acid polyglyceryl-20" with an esterification rate of 18% and a {(a) + (b)}:(c) ratio of 1:0.

[0066] <Synthesis Example 11> 186.0 g of polyglycerol having an average degree of polymerization of 20, 204.8 g (0.72 mol) of stearic acid having 18 carbon atoms, and 9.2 g (0.045 mol) of sebacic acid having 10 carbon atoms were placed in a reaction vessel, and 0.4 g of sodium hydroxide was added. After that, the reaction was carried out at 250°C for 3 hours in a nitrogen atmosphere, and a highly viscous compound with an esterification rate of 32% and a {(a) + (b)}:(c) ratio of 1:0.05 was obtained.

[0067] <Synthesis Example 12> 188.4 g of polyglycerol having an average degree of polymerization of 20, 47.2 g (0.27 mol) of capric acid having 10 carbon atoms, 155.2 g (0.46 mol) of behenic acid having 22 carbon atoms, and 9.2 g (0.045 mol) of sebacic acid having 10 carbon atoms were placed in a reaction vessel, and 0.3 g of sodium hydroxide was added. After that, the reaction was carried out at 250°C for 2 hours in a nitrogen stream, and a highly viscous compound was obtained with an esterification rate of 32% and a {(a) + (b)}:(c) ratio of 1:0.05.

[0068] <Synthesis Example 13> 307.6 g of polyglycerol having an average degree of polymerization of 20, 77.2 g (0.45 mol) of capric acid having 10 carbon atoms, and 15.2 g (0.075 mol) of sebacic acid having 10 carbon atoms were placed in a reaction vessel, and 0.04 g of sodium hydroxide was added. After that, the reaction was carried out at 240°C for 3 hours in a nitrogen stream, yielding 280 g of "polyglyceryl-20 tri(capric acid / sebacic acid)" with an esterification rate of 13% and an {(a) + (b)}:(c) ratio of 1:0.12.

[0069] In the following examples and comparative examples, the following items were evaluated.

[0070] "viscosity" The viscosity of the polyglycerol fatty acid esters of Synthesis Examples 1 to 13 at 80°C was measured using a B-type viscometer, a BM-type viscometer TVB-10M (12 rpm, rotor No. 3) manufactured by Toki Sangyo Co., Ltd., and the productivity was evaluated according to the following evaluation criteria. The results are shown in Table 1.

[0071] (Evaluation criteria) Good: Transparent or suspension-like with a viscosity of 10,000 mPa·s or less. △: Transparent or suspension-like with a viscosity of 10,000 mPa·s or more, which presents issues with operability. ×: The viscosity is 10,000 mPa·s or more, and the product is transparent or in a suspension state, which makes productivity difficult.

[0072] [Table 1]

[0073] As shown in Table 1 above, the polyglycerol fatty acid esters of Synthesis Examples 11 and 12, in which the amounts of monocarboxylic acid and dicarboxylic acid charged were large and the esterification rate exceeded 30%, exhibited very high viscosity at 80°C due to high polymerization, resulting in productivity problems. Furthermore, the compound of Synthesis Example 13, in which the esterification rate was 30% or less but the {(a) + (b)}:(c) ratio exceeded 1:0.1, also exhibited a relatively high viscosity, exceeding 10,000 mPa·s, posing a problem in terms of operability. Conversely, the compounds of Synthesis Examples 1 to 10 had low viscosity and could be easily discharged from the reactor and filtered, demonstrating superior productivity.

[0074] "Average molecular weight of polyglycerol fatty acid ester" The average molecular weights of the polyglycerol fatty acid esters of Synthesis Examples 3, 4, and 11, and 13, which differ in esterification rate, were measured by gel permeation chromatography using a Tosoh HLC-8420 GPC (column: Showa Denko Shodex GPC KF-806L x 3 + KF-801). The results were compared with the theoretical average molecular weight calculated from the hydroxyl value of polyoxyalkylene-type nonionic surfactants commonly used as solubilizers. The polyoxyalkylene-type nonionic surfactants used were PEG-40 hydrogenated castor oil (EMALEX HC-40, manufactured by Nippon Emulsion Co., Ltd.; Mn: 2715) and PEG-40 hydrogenated castor oil PCA isostearate (PYROTER CPI-40, manufactured by Nippon Emulsion Co., Ltd.; Mn: 3117). The results are shown in Table 2.

[0075] (Evaluation criteria) ◯: Has an average molecular weight similar to that of the target polyoxyalkylene nonionic surfactant. ×: The average molecular weight is different from that of the target polyoxyalkylene nonionic surfactant.

[0076] [Table 2]

[0077] As shown in Table 2 above, the polyglycerol fatty acid esters of Synthesis Examples 3 and 4 have average molecular weights comparable to those of the target polyoxyalkylene-type nonionic surfactants, making them promising solubilizers for cosmetics. The compound of Synthesis Example 11, with an esterification rate exceeding 30%, became highly viscous and insoluble in organic solvents, making it impossible to remove from the reactor. This not only reduces productivity but also makes it unsuitable as a cosmetic solubilizer. The compound of Synthesis Example 13, with a {(a) + (b)}:(c) ratio exceeding 1:0.1, became highly viscous, making removal from the reactor somewhat problematic, and also had a low esterification rate. Therefore, unlike the target polyoxyalkylene-type nonionic surfactants, its average molecular weight is not suitable as a cosmetic solubilizer. Compounds that became too viscous in the reaction vessel during the reaction and could not be removed from the reactor were not subjected to average molecular weight measurement and are therefore marked with "-."

[0078] "Critical micelle concentration of polyglycerol fatty acid esters" The critical micelle concentrations (CMC) of the polyglycerol fatty acid esters of Synthesis Examples 3 and 4 and Synthesis Examples 10 and 13 were measured using a multifunctional automatic surface tensiometer, Tensiio, manufactured by KURSS GmbH, Germany, and compared with polyoxyalkylene-type nonionic surfactants commonly used as solubilizers. The polyoxyalkylene-type nonionic surfactants used were PEG-40 hydrogenated castor oil (EMALEX HC-40, manufactured by Nippon Emulsion Co., Ltd.; CMC: 60.38 mg / L) and PEG-40 hydrogenated castor oil PCA isostearate (PYROTER CPI-40, manufactured by Nippon Emulsion Co., Ltd.; CMC: 68.91 mg / L). The results are shown in Table 3.

[0079] (Evaluation criteria) ◯: Has a CMC value similar to that of the target polyoxyalkylene nonionic surfactant. ×: The CMC value is different from that of the target polyoxyalkylene nonionic surfactant.

[0080] [Table 3]

[0081] As shown in Table 3 above, it was confirmed that the polyglycerol fatty acid esters of Synthesis Examples 3, 4, and 10 had CMCs comparable to those of the polyoxyalkylene nonionic surfactants under consideration, and that the compound of Synthesis Example 13 had a CMC value greater than that of the polyoxyalkylene nonionic surfactant under consideration. Evaluation of the solubilizing performance of these polyglycerol fatty acid esters continued.

[0082] [Solubilization ability] The polyglycerol fatty acid esters of Synthesis Examples 3, 10, and 13 were evaluated for their ability to solubilize oils used in cosmetics. The oils used were acyl amino acid-based oils: di(phytosteryl / octyldodecyl) lauroyl glutamate (ELDEW PS-203, manufactured by Ajinomoto Co., Inc.), dihexyldecyl lauroyl glutamate (AMITER LG-1600, manufactured by Nippon Emulsion Co., Ltd.), and hexyldecyl myristoylmethylaminopropionate (AMITER MA-HD, manufactured by Nippon Emulsion Co., Ltd.). The results are shown in Tables 4 and 5.

[0083] (Evaluation criteria) Good: The solubilized liquid is permeable, no floating of oil droplets or creaming is observed, and the stability is excellent. ×: The solubilized solution is not permeable, or floating of oil droplets, creaming, or phase separation is observed.

[0084] The solubilized solution was prepared by heating the oil and the polyglycerol fatty acid ester of Synthesis Example 3 or Synthesis Examples 10 and 13 to 75°C and mixing them together. An equal amount of purified water heated to 70°C was added to the mixture and mixed thoroughly, and this process was repeated twice. The remaining purified water was then added and mixed with stirring, after which the mixture was cooled to 30°C and left at 25°C for approximately 12 hours, after which the state was visually evaluated.

[0085] [Table 4]

[0086] [Table 5]

[0087] As shown in Tables 4 and 5 above, the polyglycerol fatty acid ester of Synthesis Example 3 exhibits excellent solubilizing ability when acylamino acid-based oils are used as the solubilized substance, and a stable solubilized solution can be obtained. This is thought to be because the compound of Synthesis Example 3, which contains a dicarboxylic acid in its structure, has a larger molecular weight than the compound of Synthesis Example 10 (average molecular weight: 2,140) or Synthesis Example 13, which has a low esterification rate, and is therefore more compatible with acylamino acid-based oils, which are among the oils used in cosmetics and have a higher molecular weight.

[0088] The solubilization ability when oils other than acylamino acid-based oils were used as the solubilized substance is shown in Table 6. Benzyl acetate, the solubilized substance, is the main component of jasmine and ylang-ylang, essential oils used as botanical fragrances in cosmetics.

[0089] [Table 6]

[0090] As shown in Table 6 above, the polyglycerol fatty acid esters of Synthesis Examples 2, 3, and 4, like the acylamino acid-based oils, can produce stable solubilized solutions even when the main components of essential oils, hydrocarbon oils, and ester oils are used as solubilized substances.

[0091] [Ability to solubilize poorly soluble substances] In addition to liquid oil, solubilized cosmetics are sometimes required to contain poorly soluble substances, which are components of functional cosmetics. The polyglycerin fatty acid esters of Synthesis Examples 3 and 10 and PEG-40 hydrogenated castor oil were evaluated for their solubilizing ability when phytosterol was used as the poorly soluble substance. The results are shown in Table 7.

[0092] (Evaluation criteria) ◯: The solubilized solution is permeable and no phytosterol precipitation is observed. ×: No permeability to the solubilized solution or precipitation of phytosterols is observed.

[0093] [Table 7]

[0094] As shown in Table 7 above, the polyglycerol fatty acid ester of Synthesis Example 3 can stably solubilize hexyldecyl myristoylaminopropionate containing phytosterol, a poorly soluble substance, without causing precipitation or destabilization of the phytosterol. The compound of Synthesis Example 10 and PEG-40 hydrogenated castor oil, a polyoxyalkylene-type nonionic surfactant, cause creaming, making it impossible to obtain a stable solubilized solution.

[0095] [Dispersion stability in liquid] For the solubilized solutions prepared using the polyglycerol fatty acid esters of Synthesis Examples 3, 4, and 10 and PEG-40 hydrogenated castor oil as solubilizers and acylamino acid-based oils or ester oils as solubilized substances, the turbidity was measured using a portable turbidity meter Turb430 manufactured by WTW, Germany, and the in-liquid dispersion stability was evaluated using a TURBISCAN Tower in-liquid dispersion stability evaluation device manufactured by Formulaction, France. The results are shown in Tables 8 and 9.

[0096] The liquid dispersion stability evaluation device detects transmitted and backscattered light from the sample by scanning a light source vertically across the sample tube at regular intervals. The TSI (TURBISCAN Index), an index of instability, indicates the degree of change in the sample over time and is automatically calculated by the TURBISCAN Tower using the following formula (iii). The higher the TSI value, the more the lotion becomes unstable, and the faster the value increases, the faster the instability occurs.

[0097]

number

[0098] (Evaluation criteria) Good: The turbidity is 30 or less, and the increase in TSI value after 72 hours at 40°C is within 50%. △: The turbidity exceeds 30, but the increase in TSI value after 72 hours at 40°C is within 50%. ×: The turbidity exceeds 30, or the rate of increase in TSI value after 72 hours at 40°C exceeds 50%.

[0099] [Table 8]

[0100] [Table 9]

[0101] As shown in Tables 8 and 9, the polyglycerol fatty acid esters of Synthesis Examples 3 and 4 solubilize acylamino acid-based oils and ester oils with high transmittance and exhibit excellent stability over time. The compound of Synthesis Example 10 caused creaming and the turbidity exceeded the measurement limit of the turbidimeter, so the in-liquid dispersion stability was not evaluated and is indicated as "-."

[0102] (Prescription example) Table 10 shows formulation examples of a γ-oryzanol-solubilized lotion using the solubilizing composition of the Examples, Table 11 shows formulation examples of an olive oil-solubilized lotion, Table 12 shows formulation examples of an acylamino acid ester oil-solubilized lotion, Table 13 shows formulation examples of an essential oil-solubilized lotion, Table 14 shows formulation examples of a hair mist, Table 15 shows formulation examples of a UV hair mist, Table 16 shows formulation examples of a cleansing oil, and Table 17 shows formulation examples of a transparent hair shampoo. The present invention is not limited in any way by these formulation examples.

[0103] [Table 10]

[0104] [Table 11]

[0105] [Table 12]

[0106] [Table 13]

[0107] [Table 14]

[0108] [Table 15]

[0109] [Table 16]

[0110] [Table 17]

[0111] As described above, the solubilizer compositions of the Examples were highly productive and had the same versatility as conventional polyoxyalkylene solubilizers, and cosmetics containing these solubilizer compositions were stable over time.

[0112] As described above, the solubilizer compositions of the Examples were able to provide solubilizer compositions that have excellent performance in solubilizing oil-soluble ingredients, can easily solubilize oil-soluble ingredients into a transparent to microemulsion-like state with the incorporation of a small amount, have an excellent feel when used, and have good temperature stability over time, as well as cosmetics containing such solubilizer compositions.

Claims

1. The composition contains a polyglycerol fatty acid ester which is an ester of: (a) a polyglycerol having an average degree of polymerization in the range of 15 to 50; (b) at least one selected from monocarboxylic acids having a carbon number in the range of 8 to 18; and (c) at least one selected from dicarboxylic acids having a carbon number in the range of 6 to 20; A solubilizer composition characterized in that the esterification rate of all constituent fatty acids {(b) + (c)} relative to (a) is 30% or less, and the molar ratio of {(a) + (b)}:(c) is in the range of 1:0.01 to 1:0.

1.

2. 10. The solubilizer composition of claim 1, The solubilizer composition, wherein the (b) monocarboxylic acid having 8 to 18 carbon atoms is at least one selected from caprylic acid, capric acid, lauric acid, coconut oil fatty acid, oleic acid, and isostearic acid.

3. 10. The solubilizer composition of claim 1, A solubilizer composition characterized in that the (c) dicarboxylic acid having 6 to 20 carbon atoms is at least one selected from adipic acid, sebacic acid, dodecanedioic acid, and isoeicosanedioic acid.

4. 10. The solubilizer composition of claim 1, A solubilizer composition characterized in that the viscosity of the solubilizer composition at 80°C is 10,000 mPa·s or less.

5. A cosmetic comprising the solubilizer composition according to any one of claims 1 to 4.

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