Water-in-oil emulsion cosmetic

Abstract

[Problem] The purpose of the present invention is to provide a water-in-oil type emulsion cosmetic which can be efficiently produced and has improved stability in high-temperature and low-temperature regions. [Solution] A water-in-oil emulsion cosmetic according to the present invention is characterized by comprising: (A) an ester of a C10-22 fatty acid and a polyol having at least three hydroxyl groups in the molecule; (B) one or more substances selected from the group consisting of (B-1) amino acids or salts thereof and (B-2) bivalent or higher inorganic salts; (C) glyceryl behenate / eicosane diacid ester; and (D) water.

Description

Technical Field

[0001] The present invention relates to a water-in-oil emulsified cosmetic that can be manufactured with high efficiency and has improved stability in high-temperature and low-temperature regions. Background Art

[0002] In the field of cosmetics, as techniques for emulsifying water-soluble components such as water and moisturizers with oil-soluble components such as emollients, there are various techniques as follows: for example, an emulsification method using a hydrophilic or lipophilic surfactant, an emulsification method using an α-gel in which a liquid crystal state is formed by a higher alcohol and a hydrophilic surfactant, a non-aqueous emulsification method, a mechanical emulsification method, an amino acid gel emulsification method, and the like.

[0003] Among them, in a water-in-oil emulsification system containing a large amount of water, the amino acid gel emulsification method can stably maintain the emulsified state by promoting the orientation of a specific surfactant at the interface through the salting-out effect of an amino acid (for example, Patent Document 1).

[0004] In emulsified cosmetics using amino acid gel emulsification, a wax has been conventionally added. By adding such a wax, there is an advantage of improving the stability of amino acid gel emulsification. On the other hand, if a wax is added, agglomeration is likely to occur during the manufacturing process (a state in which the wax precipitates in a solid form). Therefore, in order to suppress such agglomeration, a cooling process is required, and this cooling process has a problem of complicating the manufacturing. In addition, if a wax is added, the stability in high-temperature and low-temperature regions may decrease, or the product may have a particularly strong feeling in terms of the touch during use.

[0005] Therefore, in water-in-oil emulsified cosmetics using amino acid gel emulsification, there is a demand for efficient manufacturing and enhanced stability in high-temperature and low-temperature regions.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Laid-Open No. 8-126832 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] An object of the present invention is to provide a water-in-oil emulsified cosmetic that can be manufactured with high efficiency and has improved stability in high-temperature and low-temperature regions.

[0011] The inventors conducted in-depth research on the above-mentioned problems and found that by using an ester of a fatty acid having 10 to 22 carbon atoms and a polyol having at least 3 or more hydroxyl groups in the molecule, and one or more selected from amino acids or their salts and inorganic salts of divalent or higher valency, the orientation of the above-mentioned surfactant at the interface can be promoted. Furthermore, by using glyceryl behenate / eicosanedioate as an oil-phase thickener, a cosmetic having high emulsion stability even at high and low temperatures can be obtained, and thus the present invention was completed.

[0012] That is, the present invention provides a water-in-oil emulsion cosmetic, which is characterized by comprising:

[0013] (A) an ester of a fatty acid having 10 to 22 carbon atoms and a polyol having at least 3 or more hydroxyl groups in the molecule;

[0014] (B) one or more selected from the following (B-1) and (B-2);

[0015] (B-1) an amino acid or its salt,

[0016] (B-2) an inorganic salt of divalent or higher valency,

[0017] (C) glyceryl behenate / eicosanedioate; and

[0018] (D) water.

[0019] Effects of the Invention

[0020] With the above constitution, the present invention can obtain a cosmetic having high emulsion stability in a wide temperature range in a water-in-oil emulsion cosmetic containing a large amount of water. Moreover, compared with conventional emulsion cosmetics emulsified with an amino acid gel, the cosmetic of the present invention can be manufactured more efficiently. In addition, in addition to the components (A) to (D) above, by using (E) dimethylsilylated silica, a water-in-oil emulsion cosmetic having a heavy and rich feeling and good extensibility during application can be obtained.

[0021] In the present invention, the "heavy feeling" means a feeling of having an appropriate sense of weight and elasticity during the application process; the "rich feeling" means a residual feeling as if the cosmetic is covering the skin after the cosmetic is applied to the skin. Detailed Embodiments

[0022] The water-in-oil emulsion cosmetic of the present invention is characterized by comprising: (A) an ester of a fatty acid having 10 to 22 carbon atoms and a polyol having at least 3 or more hydroxyl groups in the molecule; (B) at least one selected from (B-1) an amino acid or its salt and (B-2) an inorganic salt having a valence of 2 or more; (C) glyceryl behenate / eicosandioate; and (D) water. Hereinafter, each component constituting the cosmetic of the present invention will be described in detail.

[0023] <(A) Ester of a fatty acid having 10 to 22 carbon atoms and a polyol having at least 3 or more hydroxyl groups in the molecule>

[0024] The ester of a fatty acid having 10 to 22 carbon atoms and a polyol having at least 3 or more hydroxyl groups in the molecule (hereinafter sometimes simply referred to as “component (A)”) blended in the cosmetic of the present invention is an ester of a saturated fatty acid or an unsaturated fatty acid having 10 to 22 carbon atoms and a polyol having at least 3 or more hydroxyl groups in the molecule, and is liquid at normal temperature (about 25°C).

[0025] As the polyol constituting component (A), it is a substance having 3 or more hydroxyl groups, and specific examples include: glycerol, diglycerol, triglycerol, tetraglycerol, pentaglycerol, hexaglycerol, octaglycerol, nonaglycerol, decaglycerol, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitan, sorbitol, etc. As the fatty acid constituting component (A), examples include: lauric acid, palmitic acid, myristic acid, stearic acid, caprylic acid, capric acid, oleic acid, linoleic acid, ricinoleic acid, isooctanoic acid, isomyristic acid, isopalmitic acid, isostearic acid, etc.

[0026] Esters generally mainly refer to single components such as monoesters, diesters, triesters, and a part of tetraesters and pentaesters, or mixtures thereof. When it is a mixture, the ideal mixing ratio varies depending on the type of carboxylic acid and the number of hydroxyl groups in the polyol. For example, for glycerol esters having 3 hydroxyl groups, when using a fatty acid having 18 carbon atoms, it is preferably mainly formed of a mixture of monoesters and diesters. In addition, among fatty acids having 18 carbon atoms, for esters having different numbers of hydroxyl groups, for example: glycerol or trimethylolpropane having 3 hydroxyl groups is preferably mainly formed of a mixture of monoesters and diesters; diglycerol having 4 hydroxyl groups is preferably mainly formed of a mixture of monoesters, diesters, and a part of triesters; in addition, sorbitol having 6 hydroxyl groups is preferably mainly formed of a mixture of diesters, triesters, and a part of tetraesters.

[0027] Examples of the component (A) include: glyceryl mono(2-heptylundecanoate), trimethylolpropane mono(2-heptylundecanoate), diglyceryl di(2-heptylundecanoate), glyceryl mono(9-methyloctadecanoate), trimethylolpropane mono(9-methyloctadecanoate), diglyceryl di(9-methyloctadecanoate), pentaerythritol di(9-methyloctadecanoate), glyceryl monooleate, trimethylolpropane monooleate, diglyceryl dioleate, glyceryl diricinoleate, sorbitan mono(di)oleate, sorbitan di(tri)oleate.

[0028] Among them, as the component (A), glycerol fatty acid ester is preferred, and glycerol fatty acid ester having a saturated or unsaturated fatty acid with 18 carbon atoms is more preferred. As the component (A), glyceryl oleate and polyglyceryl diisostearate are preferably used.

[0029] As the component (A) of the present invention, one of the above substances can be used alone, or two or more thereof can be used in combination.

[0030] The lower limit value of the blending amount of the component (A) is preferably 0.5% by mass or more, more preferably 1% by mass or more, and further preferably 1.5% by mass or more, based on the total amount of the cosmetic. As the upper limit value, it is preferably 15% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less, based on the total amount of the cosmetic. Therefore, examples of the blending amount range include 0.5 to 15% by mass, 1 to 10% by mass, etc. If the blending amount of the component (A) is less than 0.5% by mass, sufficient stability may sometimes not be obtained, and if it exceeds 15% by mass, there is a tendency for usability to decrease.

[0031] <(B) is selected from one or more of amino acids or their salts and inorganic salts of divalent or higher valence>

[0032] The component (B) incorporated in the cosmetic of the present invention is one or more selected from (B-1) amino acids or their salts and (B-2) inorganic salts of divalent or higher valence (hereinafter sometimes simply referred to as the “component (B)”).

[0033] In the conventional amino acid gel emulsification method, by using an amino acid or its salt, the salting-out effect of the amino acid can promote the orientation of a specific surfactant at the interface, and the emulsified state can be stably maintained. The insight obtained in the present invention is that even if an inorganic salt of divalent or higher valence is used instead of an amino acid or its salt, the orientation of a specific surfactant at the interface can also be promoted.

[0034] The (B-1) amino acid or its salt (hereinafter sometimes simply referred to as the "(B-1) component") of the present invention is not particularly limited as long as it is an amino acid or its salt that can generally be incorporated into cosmetics. Examples of amino acids include L-alanine, β-alanine, L-arginine hydrochloride, L-asparagine monohydrate, L-aspartic acid, L-citrulline, L-glutamic acid, L-glutamic acid hydrochloride, L-glutamine, glycine, L-histidine, L-histidine hydrochloride monohydrate, L-hydroxyproline, L-isoleucine, L-leucine, L-lysine, L-lysine hydrochloride, L-ornithine hydrochloride, L-proline, L-phenylalanine, L-serine, L-threonine, L-tryptophan, L-tyrosine, L-valine, L-dopa, and L-α-aminobutyric acid and other L-amino acids. In addition, the D-form and DL-form of isomers are the same. Among these, those preferably selected from L-glutamic acid, glycine, L-hydroxyproline, L-alanine, β-alanine, L-proline, and L-serine. Examples of salts include monovalent metal salts such as sodium, potassium, and lithium, and divalent metal salts such as calcium and magnesium.

[0035] As the (B-1) component of the present invention, those preferably selected from sodium L-asparaginate, potassium L-asparaginate, sodium L-glutamate, and potassium L-glutamate.

[0036] The (B-2) inorganic salt with a valence of two or more (hereinafter sometimes simply referred to as the "(B-2) component") of the present invention is not particularly limited as long as it is an inorganic salt with a valence of two or more that can generally be incorporated into cosmetics. Examples of inorganic acids that can form inorganic salts include hydrochloric acid, phosphoric acid, nitric acid, sulfuric acid, boric acid, and hydrofluoric acid. Examples of divalent salts include magnesium, calcium, and barium.

[0037] As the (B-2) component of the present invention, those preferably selected from calcium chloride, magnesium chloride, and magnesium sulfate.

[0038] The lower limit value of the blending amount of the (B) component is preferably 0.5% by mass or more, more preferably 1% by mass or more, and further preferably 1.5% by mass or more, relative to the total amount of the cosmetics. The upper limit value is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less, relative to the total amount of the cosmetics. Therefore, examples of the blending amount range include 0.5 to 10% by mass, 1 to 5% by mass, etc. If the blending amount of the (B) component is less than 0.5% by mass, sufficient stability may sometimes not be obtained; if it exceeds 10% by mass, there is a tendency for usability to decline.

[0039] <(C) Glyceryl behenate / eicosanedioate>

[0040] The glyceryl behenate / eicosadioate (hereinafter sometimes simply referred to as "(C) component") of the present invention refers to an oligomer obtained by condensing a mixed fatty acid composed of behenic acid and eicosadioic acid with glycerol.

[0041] Examples of commercially available products of the (C) component include NOMCORT HK-G (manufactured by Nisshin OilliO Group, Ltd.).

[0042] The lower limit value of the blending amount of the (C) component is preferably 0.2% by mass or more, more preferably 0.5% by mass or more, and further preferably 0.8% by mass or more, relative to the total amount of the cosmetic. The upper limit value is preferably 10% by mass or less, more preferably 7% by mass or less, further preferably 5% by mass or less, and even more preferably 3% by mass or less, relative to the total amount of the cosmetic. Therefore, examples of the blending amount range include 0.2 to 10% by mass, 0.5 to 7% by mass, 0.8 to 5% by mass, etc. If the blending amount of the (C) component is less than 0.2% by mass, sufficient stability may sometimes not be obtained, and if it exceeds 10% by mass, there is a tendency for stability to deteriorate.

[0043] In addition, the blending ratio of the (C) component in the oil phase (all oily components) of the cosmetic is preferably 2 to 20% by mass ratio, more preferably 2.5 to 12%. The "oil phase" or "all oily components" refers to the total of the components that are mixed with the oil component to form the oil phase among the components constituting the water-in-oil emulsion cosmetic of the present invention. For example, in Table 2 described later, the components classified as (A) component, oil component, (C) component, and (E) component in total form the oil phase.

[0044] The (D) water blended in the cosmetic of the present invention can be ion-exchanged water, purified water, tap water, natural water, etc. as needed. The blending amount is the balance (mass% relative to the total amount of the cosmetic) with respect to the sum of the essential components and other optional blending components of the present invention. Generally, it is appropriate to be 30 to 70% by mass, preferably about 40 to 60% by mass, relative to the total amount of the cosmetic.

[0045] In the water-in-oil emulsion cosmetic of the present invention, by blending the above-mentioned (A) to (C) components, a large amount of aqueous components can be stably blended. For example, in the cosmetic of the present invention, 20 to 80% by mass, 30 to 75% by mass, or about 50 to 70% by mass of aqueous components are preferably blended as the internal phase relative to the total amount of the cosmetic.

[0046] In the water-in-oil emulsion cosmetic of the present invention, by further using (E) dimethylsilylated silica in addition to the above-mentioned (A) to (C) components, a cosmetic having a thick and rich feel during use and good spreadability during application can be obtained.

[0047] The (E) dimethylsilylated silica that can be incorporated in the cosmetic of the present invention (hereinafter sometimes simply referred to as the "(E) component") refers to silica obtained by hydrophobically treating the surface of silica having a primary particle size of 5 to 50 nm and a specific surface area of 90 to 300 m 2 / g with dimethyldichlorosilane.

[0048] Examples of commercially available products of the (E) component include Aerosil (registered trademark) R972, R974, R9200, R976, R976S (manufactured by NIPPON AEROSIL CO., LTD.).

[0049] The blending amount of the (E) component is preferably such that the effects of blending this component can be exhibited, and within the limit that there are no drawbacks such as deterioration of the usage feeling due to excessive blending amount. The preferred blending amount of the (E) component in the cosmetic of the present invention is preferably about 0.5 to 5% by mass or 1 to 3% by mass based on the total amount of the cosmetic.

[0050] In the cosmetic of the present invention, in addition to the above components, within the range that does not impair the object and effects of the present invention, other arbitrary components used in ordinary cosmetics and skin external preparations such as drugs can be appropriately blended as needed. Examples of other arbitrary components include oil components, powder components, ultraviolet absorbers, nonionic, cationic, and silicone surfactants, lower alcohols, polyhydric alcohols, chelating agents, pH adjusters, antioxidants, food flavorings, preservatives, bactericides, various medicaments, etc., other than the above (A) components. However, it is not limited to these exemplified examples.

[0051] Examples of the oil component other than the component (A) described above include hydrocarbon oils such as mineral oil, hydrogenated polydecene, isocetane, isododecane, ozokerite, squalane, squalene, pristane, paraffin wax, isoparaffin, ceresin, petrolatum, hydrogenated polyisobutene, and olefin oligomer; ester oils such as pentaerythritol tetra(ethylhexanoate), cetyl ethylhexanoate, jojoba (SIMMONDSIA CHINENSIS) seed oil, phytosterol / octyldodecyl lauroylglutamate, triisostearin, glycerin diisostearate, glycerin tri(ethylhexanoate), phytosterol / isostearyl / cetyl / stearyl / behenyl dimer dilinoleate, isopropyl palmitate, ethylhexyl palmitate, myristyl myristate, isopropyl myristate, tripropylene glycol dineopentanoate, diisopropyl sebacate, isodecyl neopentanoate; chain silicone oils such as dimethylpolysiloxane, methylphenylpolysiloxane, and methylhydrogenpolysiloxane; cyclic silicone oils such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane; liquid oils such as linseed (LINUM USITATISSIMUM) oil, camellia (CAMELLIA JAPONICA) seed oil, macadamia integrifolia seed oil, corn oil, mink oil, olive (OLEA EUROPAEA) fruit oil, avocado (PERSEA GRATISSIMA) oil, camellia kissi seed oil, castor (RICINUS COMMUNIS) seed oil, safflower (CARTHAMUS TINCTORIUS) seed oil, rapeseed oil, soybean oil, peanut oil, triglycerol, glycerin tri(ethylhexanoate), and glycerin triisopalmitate, etc.

[0052] In the cosmetic of the present invention, wax can be blended within the range that does not affect the effects of the present invention. When wax is blended, it is preferably 5% by mass or less, more preferably 3% by mass or less, and further preferably 1% by mass or less. In addition, the form of the cosmetic of the present invention also includes a form in which wax is not blended. Here, wax refers to waxes having a melting point of 60°C or higher under one atmospheric pressure, such as beeswax, sumac wax, candelilla (EUPHORBIA CERIFERA) wax, carnauba (COPERNICIA CERIFERA) wax; polyolefin wax, microcrystalline wax, solid paraffin wax, synthetic wax, etc.

[0053] The cosmetics of the present invention can be manufactured according to the conventional manufacturing method using amino acid gel emulsification. That is, the powder component and the oil phase component are mixed while heating as needed to obtain an oil phase component mixture in which the powder component is uniformly dispersed. Separately, the mixed solution (gel phase) obtained by dissolving the components (A) and (B) of the present invention and a part of water is mixed into the above oil phase component mixture and emulsified. Furthermore, the water phase component mixture obtained by mixing and dissolving the remaining water and the aqueous components separately is added to the above emulsion, and further mixed and emulsified to obtain a water-in-oil type emulsified cosmetic.

[0054] The cosmetics of the present invention can be made into dosage forms such as paste, ointment, and balm. Among them, it is particularly suitable to be made into an ointment cosmetic filled in a wide-mouth container or a hose for use.

[0055] Examples

[0056] Examples are given below to explain the present invention in more detail, but the present invention is not limited by any of these contents. Unless otherwise specified, the blending amount is expressed as the mass % of the component in the system where it is located. Before specifically describing each example, the evaluation method adopted will be described first.

[0057] 1. Stability evaluation

[0058] Prepare the paste water-in-oil type emulsified cosmetics in each example, and after standing at room temperature for 4 weeks, observe its appearance visually and evaluate it according to the following evaluation criteria. In addition, the appearance after standing at low temperature (0°C) and high temperature (50°C) for 4 weeks respectively is also evaluated in the same way.

[0059] (Evaluation criteria)

[0060] A: The appearance has not changed.

[0061] B: Slight changes can be observed on the surface of the cosmetics, but there is no problem in use.

[0062] C: Slight water separation (low temperature) or solidification (high temperature) is observed.

[0063] D: Significant water separation (low temperature) or solidification (high temperature) is observed.

[0064] 2. Evaluation of the feel in use

[0065] For each of the prepared cosmetics, 10 professional evaluators conducted actual use tests. For the use feel (heaviness, richness) when applying each sample to the skin, evaluation was carried out according to the following criteria. Herein, "heaviness" refers to the feeling of having an appropriate sense of weight and elasticity during the application process, and "richness" refers to the residual feeling as if the cosmetic covers the skin after applying the cosmetic to the skin and making it adhere.

[0066] <Evaluation Criteria>

[0067] A: More than 8 people evaluated as having heaviness and richness.

[0068] B: 5 - 7 people evaluated as having heaviness and richness.

[0069] ST: 2 - 4 people evaluated as having heaviness and richness.

[0070] (Examples, Comparative Examples)

[0071] For the water-in-oil emulsion cosmetics (creams) having the compositions listed in Tables 1 and 2 below, after dispersing the powder component in the oily component obtained by mixing using a homogenizer, the gel phase and the aqueous component obtained by separate mixing were added in sequence and emulsified to obtain the cosmetics. For the prepared cosmetics, their stability and use feel were evaluated according to the above evaluation method. The results are listed in the table together.

[0072] [Table 1]

[0073]

[0074] The oil-phase thickeners used in Comparative Examples 1 - 4 of Table 1 are oil-phase thickeners commonly used in water-in-oil emulsion cosmetics. In addition, the cosmetic of Comparative Example 5 is a conventional water-in-oil emulsion cosmetic based on amino acid gel emulsification, in which wax is incorporated into the emulsion obtained by amino acid gel emulsification.

[0075] The cosmetic of Comparative Example 2 has poor stability and cannot be evaluated at high and low temperatures. The cosmetics of Comparative Examples 1, 3 - 4 have poor stability over time, especially at high temperatures. The cosmetic of Comparative Example 5 contains a large amount of wax, so a rapid cooling process is required during the manufacturing process, and not only is its stability poor at high temperatures, but its stability is also poor in the low-temperature region.

[0076] On the other hand, the cosmetic of Example 1 using (C) glyceryl behenate / eicosanedioate as the oil-phase thickener has excellent stability in any temperature region.

[0077] [Table 2]

[0078]

[0079] Cosmetics in which various changes have been made to the component (A) of the present invention are prepared. Examples 2 and 3 are examples in which the blending amounts of the component (C) are different. These cosmetics are excellent in stability in both low-temperature and high-temperature regions.

[0080] Compared with the cosmetics of Example 1, more evaluators evaluated the cosmetics of Examples 2 to 7 containing the component (E) as having a heavy and rich feeling.

[0081] In addition, compared with the cosmetics of Example 2 in which the blending ratio of the component (C) in the oil phase is less than 2% by mass, the emulsion stability of the cosmetics of Examples 3 to 7 with 2% by mass or more is further improved.

[0082] Therefore, by using the component (E) in addition to the components (A) to (D) of the present invention, cosmetics excellent in emulsion stability in a wide temperature range and having a heavy and rich feeling can be obtained.

[0083] Although the results are not shown in the table, the spreadability (the spreading state when the cosmetics are applied to the skin) of the cosmetics of Examples 1 to 7 during application was evaluated. The results showed that compared with the cosmetics of Example 1, the cosmetics of Examples 2 to 7 had an appropriate sense of weight during application and were excellent in terms of spreadability. Thus, by blending the component (E) in the cosmetics of the present invention, the spreadability during application can be improved.

Claims

1. An oil-in-water emulsified cosmetic, comprising: (A) An ester of a fatty acid having 10 to 22 carbon atoms and a polyol having at least 3 or more hydroxyl groups in the molecule; (B) One or more selected from the following (B-1) and (B-2); (B-1) An amino acid or a salt thereof, (B-2) An inorganic salt having a valence of 2 or more, (C) Glyceryl behenate / eicosanedioate; and (D) Water.

2. The water-in-oil emulsion cosmetic according to claim 1, wherein, The component (A) is a glyceryl fatty acid ester.

3. The water-in-oil emulsion cosmetic according to claim 1, wherein, The component (A) is a glyceryl fatty acid ester having a saturated or unsaturated fatty acid with 18 carbon atoms.

4. The water-in-oil emulsion cosmetic according to claim 1, wherein, The component (A) is one or more selected from glyceryl oleate and polyglyceryl diisostearate.

5. The water-in-oil emulsion cosmetic according to claim 1, wherein, The component (B) is (B-1) an amino acid or a salt thereof.

6. The water-in-oil emulsion cosmetic according to claim 1, wherein, The component (B) is glutamic acid or a salt thereof.

7. The oil-in-water emulsified cosmetic according to claim 1, further comprising (E) dimethylsilylated silica.

8. The water-in-oil emulsion cosmetic according to claim 1, wherein, The mixing ratio of the component (C) in the oil phase of the cosmetic is 2 to 20% by mass.

Images