Oil-in-water emulsion composition

Abstract

The present invention provides an oil-in-water emulsion composition which has both fresh feeling of use and high ultraviolet light shielding effects, while ameliorating the problem of conspicuous whiteness after the application to the skin due to an ultraviolet scattering agent.　An oil-in-water emulsion composition, in particular, a cosmetic composition which contains the following components (a) to (c): (a) an ultraviolet scattering agent; (b) a polyhydroxystearic acid; and (c) an oil component. With respect to this composition, the ultraviolet scattering agent is dispersed in the oil component; the amount of the ultraviolet scattering agent is 50 parts by mass or more relative to 100 parts by mass of the oil component; and 55% by mass or more of the oil component is composed of a polar oil.

Description

Oil-in-water emulsion composition

[0001] The present invention relates to an oil-in-water emulsion composition, particularly a cosmetic composition.

[0002] BACKGROUND ART Various sunscreen cosmetic compositions have been developed from the viewpoint of protecting the skin from sunlight.

[0003] For example, Patent Document 1 discloses an oil-in-water emulsion cosmetic that contains an ultraviolet absorber and an ultraviolet scattering agent, has a high ultraviolet protection factor (SPF), and has a uniquely refreshing feel when used, and is characterized by containing: (A) 0.05 to 1 mass % of a hydrophobically modified alkyl cellulose; (B) 5 to 40 mass % of an oil content; (C) 2.5 to 30 mass % of an ultraviolet scattering agent having a hydrophobic surface; and (D) an aqueous phase thickener with low salt tolerance, wherein the ultraviolet scattering agent (C) is dispersed in the oil phase.

[0004] JP 2015-120682 A

[0005] In order to obtain a fresh feeling when used in an oil-in-water sunscreen cosmetic composition, it is necessary to use a formulation that reduces the amount of oil. On the other hand, UV scattering agents such as titanium oxide are generally formulated by dispersing them in an oil such as silicone oil. Furthermore, in order to obtain a sufficient sunscreen effect (i.e., UV protection effect), it is desirable to increase the amount of UV scattering agent and the amount of UV absorber, which is a polar oil.

[0006] Therefore, even if the amount of oil (e.g., the amount of oil such as silicone oil or hydrocarbon oil) is reduced, it is necessary to maintain the amount of active ingredients (i.e., UV scattering agent and UV absorber) that contribute to the sunscreen effect. In other words, it is necessary to relatively increase the proportion of UV absorber, which is a polar oil, in the small amount of oil, and to increase the proportion of UV scattering agent relative to such oil.

[0007] However, it was not easy to disperse a higher proportion of ultraviolet scattering agent than usual in such oil, i.e., in oil containing a higher proportion of polar oil such as an ultraviolet absorber than usual.

[0008] In order to improve the dispersibility of the ultraviolet scattering agent in such oil, it is conceivable to use, for example, a dispersant.

[0009] However, through intensive research by the present inventors, it has been found that when a general dispersing agent is incorporated into a cosmetic composition, there is a problem in that the whiteness resulting from the ultraviolet scattering agent becomes noticeable after application to the skin.

[0010] The present invention aims to improve the above-mentioned circumstances, and its object is to provide an oil-in-water emulsion composition that combines a fresh feeling in use with a high ultraviolet protection effect, and that overcomes the problem of noticeable whiteness caused by an ultraviolet scattering agent after application to the skin.

[0011] The present invention that achieves the above object is as follows.

[0012] Aspect 1: An oil-in-water emulsion composition, particularly a cosmetic composition, comprising the following components (a) to (c): (a) an ultraviolet scattering agent, (b) polyhydroxystearic acid, and (c) an oil component, wherein the ultraviolet scattering agent is dispersed in the oil component, the ultraviolet scattering agent is present in an amount of 50 parts by mass or more relative to 100 parts by mass of the oil component, and 55% by mass or more of the oil component is a polar oil. Aspect 2: The composition according to Aspect 1, wherein the content of the ultraviolet scattering agent is 5.0% by mass or more. Aspect 3: The composition according to Aspect 1 or 2, wherein the content of the oil component is 20% by mass or less. Aspect 4: The composition according to any one of Aspects 1 to 3, wherein the polyhydroxystearic acid is present in an amount of 3.0 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the ultraviolet scattering agent. Aspect 5: The composition according to any one of Aspects 1 to 4, wherein the polar oil is present in an amount of 80% by mass or more of the oil component. Aspect 6: The composition according to any one of Aspects 1 to 5, wherein the polar oil comprises an ultraviolet absorber. Aspect 7: The composition according to any one of Aspects 1 to 6, further comprising (d) an emulsifier. Aspect 8: The composition according to any one of Aspects 1 to 7, further comprising (e) an aqueous phase thickener. Aspect 9: The composition according to any one of Aspects 1 to 8, which is a sunscreen cosmetic composition.

[0013] According to the present invention, it is possible to provide an oil-in-water emulsion composition that combines a fresh feeling in use with a high ultraviolet protection effect, and that overcomes the problem of noticeable whiteness caused by an ultraviolet scattering agent after application to the skin.

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the preferred embodiments. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the present invention.

[0015] <<Composition>> The composition of the present invention is an oil-in-water emulsion composition, particularly a cosmetic composition, comprising the following components (a) to (c): (a) an ultraviolet scattering agent, (b) polyhydroxystearic acid, and (c) an oil component, wherein the ultraviolet scattering agent is dispersed in the oil component, the amount of the ultraviolet scattering agent is 50 parts by mass or more per 100 parts by mass of the oil component, and 55% by mass or more of the oil component is a polar oil.

[0016] The composition of the present invention can exhibit the effects of the present invention by containing this specific component.

[0017] As described above, in order to combine a fresh feeling in use with a high UV protection effect, the present inventors attempted to increase the proportion of UV scattering agent in an oil component containing a high proportion of polar oil. However, they discovered that the use of such a composition caused a problem in that the whiteness caused by the UV scattering agent became noticeable after application to the skin.

[0018] To solve this problem, the present inventors have conducted extensive research into various dispersants for UV scattering agents, and have found that the use of polyhydroxystearic acid can alleviate the problem of noticeable whiteness on the skin due to the UV scattering agent after application of the composition.

[0019] The specific components of the compositions of the present invention are described in detail below.

[0020] (a) Ultraviolet Scattering Agent The composition of the present invention contains an ultraviolet scattering agent, which can provide ultraviolet protection effect.

[0021] In the present invention, the ultraviolet scattering agent is not particularly limited as long as it has an ultraviolet protection effect, and may be, for example, at least one selected from the group consisting of titanium oxide, zinc oxide, iron oxide, and cerium oxide.

[0022] The ultraviolet scattering agent may be hydrophobized. Here, the hydrophobization treatment may be carried out using a known surface treatment agent capable of hydrophobizing the surface, and examples thereof include fluorine compound treatment, silicone treatment, silicone resin treatment, pendant treatment, silane coupling agent treatment, titanium coupling agent treatment, oil treatment, N-acylated lysine treatment, polyacrylic acid treatment, metal soap treatment, amino acid treatment, inorganic compound treatment, plasma treatment, mechanochemical treatment, silane compound treatment, and silazane compound treatment. Among these treatments, treatment with silicone or silicone resin, treatment with a silane compound or silazane compound, and metal soap treatment such as aluminum isostearate are preferred from the viewpoint of dispersion stability, etc.

[0023] The ultraviolet scattering agent may be in the form of particles, and in this case, the average primary particle diameter is not particularly limited and may be, for example, 5 nm or more, 10 nm or more, or 15 nm or more, or 200 nm or less, 100 nm or less, or 50 nm or less. The "average primary particle diameter" may be determined, for example, as the diameter of a circle equivalent to the projected area of ​​the primary particles in an SEM image.

[0024] The shape of the ultraviolet scattering agent is not particularly limited, and examples thereof include spherical, plate-like, rod-like, spindle-like, needle-like, and irregular shapes.

[0025] In the present invention, the ultraviolet scattering agent is dispersed in the oil of the composition of the present invention, and is 50 parts by mass or more relative to 100 parts by mass of the oil.Here, from the viewpoint of improving the ultraviolet protection effect, in the composition of the present invention, the ultraviolet scattering agent may be, for example, 50 parts by mass or more, 55 parts by mass or more, 60 parts by mass or more, 65 parts by mass or more, 70 parts by mass or more, 75 parts by mass or more, 80 parts by mass or more, 85 parts by mass or more, 90 parts by mass or more, 95 parts by mass or more, or 100 parts by mass or more relative to 100 parts by mass of the oil.In addition, the upper limit of the amount of the ultraviolet scattering agent dispersed in the oil is not particularly limited, and for example, the ultraviolet scattering agent may be 200 parts by mass or less, or 150 parts by mass or less relative to 100 parts by mass of the oil.

[0026] Furthermore, in the composition of the present invention, the content of the ultraviolet scattering agent is not particularly limited and may be, for example, 5.0 mass% or more, 7.0 mass% or more, 10 mass% or more, 12 mass% or more, or 15 mass% or more, and may be 30 mass% or less, or 20 mass% or less.

[0027] (b) Polyhydroxystearic Acid The composition of the present invention contains polyhydroxystearic acid, which mainly serves to uniformly disperse the ultraviolet ray scattering agent in the oil.

[0028] In the present invention, the polyhydroxystearic acid may be a compound in which hydroxystearic acid is oligomerized by forming an ester bond, or a commercially available product may be used. The degree of polymerization of the polyhydroxystearic acid is not particularly limited and may be, for example, 4 to 8.

[0029] In the composition of the present invention, the content of polyhydroxystearic acid is not particularly limited and may be appropriately adjusted according to the content of the ultraviolet ray scattering agent. More specifically, the content of polyhydroxystearic acid may be, for example, 0.1 mass% or more, 0.5 mass% or more, or 1.0 mass% or more, and may be 3.0 mass% or less, 2.5 mass% or less, 2.0 mass% or less, or 1.5 mass% or less.

[0030] Furthermore, in the composition of the present invention, the amount of polyhydroxystearic acid may be, for example, 3.0 parts by mass or more, 3.5 parts by mass or more, 4.0 parts by mass or more, 4.5 parts by mass or more, 5.0 parts by mass or more, 5.5 parts by mass or more, 6.0 parts by mass or more, or 6.5 parts by mass or more, relative to 100 parts by mass of the UV scattering agent, from the viewpoint of improving the dispersibility of the UV scattering agent in oil, and may be 10 parts by mass or less, 9.0 parts by mass or less, or 8.0 parts by mass or less, from the viewpoint of stability against emulsification.

[0031] (c) Oil Component The composition of the present invention contains an oil component.

[0032] In the composition of the present invention, the oil content is not particularly limited, and may be, for example, 25% by mass or less, 23% by mass or less, 20% by mass or less, 19% by mass or less, or 18% by mass or less from the viewpoint of improving the fresh feeling when used, and may be, for example, 10% by mass or more, or 15% by mass or more from the viewpoint of dispersing the ultraviolet scattering agent or increasing the content of the polar oil having an ultraviolet protection effect.

[0033] In the present invention, the oil component comprises a polar oil. For example, in the composition of the present invention, the polar oil accounts for 55% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 85% by mass or more of the oil component. In addition, the upper limit of the proportion of the polar oil in the oil component is not particularly limited, and for example, the polar oil may account for 100% by mass of the oil component.

[0034] Typical examples of polar oils include ester oils and ultraviolet absorbers.Among these, from the viewpoint of improving ultraviolet protection effect while obtaining a fresh feeling of use, it is preferable that the polar oil contains an ultraviolet absorber.Therefore, the proportion of the ultraviolet absorber contained in the polar oil is, for example, 40% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more of the polar oil.In addition, since the polar oil contains a larger amount than conventional cosmetic compositions, for example, highly polar fragrances and the like can also be stably blended.

[0035] (ester oil) Specific examples of ester oils that can be used as polar oils in the present invention include tripropylene glycol dineopentanoate, isononyl 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, cholesteryl 12-hydroxystearate, cetyl ethylhexanoate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid esters, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, tetra-2-ethyl Pentaerythrityl hexanoate, triethylhexanoin (glycerin tri-2-ethylhexanoate), glycerin trioctanoate, glycerin triisopalmitate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glycerin trimyristate, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, acetoglyceride, 2-heptyl palmitate Examples of suitable oleic acid surfactants include, but are not limited to, 2-hexylundecyl lauroyl undecyl adipate, diisobutyl adipate, N-lauroyl-L-glutamic acid 2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, isodecyl pivalate, 2-ethylhexyl succinate, and triethyl citrate.

[0036] (Ultraviolet Absorber) In the present invention, specific examples of ultraviolet absorbers that can be used as polar oils include, but are not limited to, benzoic acid derivatives, salicylic acid derivatives, cinnamic acid derivatives, dibenzoylmethane derivatives, β,β-diphenylacrylate derivatives, benzophenone derivatives, benzylidene camphor derivatives, phenylbenzimidazole derivatives, triazine derivatives, phenylbenzotriazole derivatives, anthranil derivatives, imidazoline derivatives, benzalmalonate derivatives, 4,4-diarylbutadiene derivatives, etc. Some specific examples and trade names of these will be described below.

[0037] Examples of benzoic acid derivatives include, but are not limited to, ethyl para-aminobenzoate (PABA), ethyl-dihydroxypropyl PABA, ethylhexyl-dimethyl PABA (e.g., "Escarol 507"; manufactured by ISP), glyceryl PABA, PEG-25-PABA (e.g., "Uvinal P25"; manufactured by BASF), and diethylaminohydroxybenzoylhexyl hexyl benzoate (e.g., "Uvinal A Plus").

[0038] Examples of salicylic acid derivatives include, but are not limited to, homosalate (Eusolex HMS; manufactured by Rona / EM Industries), ethylhexyl salicylate (e.g., NeoHeliopan OS; manufactured by Herman & Reimer), dipropylene glycol salicylate (e.g., Dipsal; manufactured by Skell), and TEA salicylate (e.g., NeoHeliopan TS; manufactured by Herman & Reimer).

[0039] Examples of cinnamic acid derivatives include ethylhexyl methoxycinnamate (octyl methoxycinnamate; for example, "Uvinal MC80"; manufactured by BASF Japan Ltd.), isopropyl methoxycinnamate, isoamyl methoxycinnamate (for example, "Neo Heliopan E1000"; manufactured by Herman & Reimer), cinnoxate, DEA methoxycinnamate, diisopropyl methylcinnamate, glyceryl-ethylhexanoate-dimethoxycinnamate, and di-(2-ethylhexyl)-4'-methoxybenzalmalonate, but are not limited to these.

[0040] Dibenzoylmethane derivatives include, but are not limited to, 4-tert-butyl-4'-methoxydibenzoylmethane (for example, Parsol 1789).

[0041] Examples of β,β-diphenylacrylate derivatives include, but are not limited to, octocrylene (for example, "Uvinal N539" manufactured by BASF).

[0042] Examples of the benzophenone derivatives include, but are not limited to, benzophenone-1 (e.g., "Uvinal 400"; manufactured by BASF), benzophenone-2 (e.g., "Uvinal D50"; manufactured by BASF), benzophenone-3 or oxybenzone (e.g., "Uvinal M40"; manufactured by BASF), benzophenone-4 (e.g., "Uvinal MS40"; manufactured by BASF), benzophenone-5, benzophenone-6 (e.g., "Helisorb 11"; manufactured by Norquay), benzophenone-8 (e.g., "Spectra-Sorb UV-24"; manufactured by American Cyanamid), benzophenone-9 (e.g., "Uvinal DS-49"; manufactured by BASF), and benzophenone-12.

[0043] Examples of benzylidene camphor derivatives include, but are not limited to, 3-benzylidene camphor (e.g., "Mexoryl SD"; manufactured by Cimex), 4-methylbenzylidene camphor, benzylidene camphorsulfonic acid (e.g., "Mexoryl SL"; manufactured by Cimex), camphor benzalkonium methosulfate (e.g., "Mexoryl SO"; manufactured by Cimex), terephthalidene discamphorsulfonic acid (e.g., "Mexoryl SX"; manufactured by Cimex), and polyacrylamidomethyl benzylidene camphor (e.g., "Mexoryl SW"; manufactured by Cimex).

[0044] Examples of phenylbenzimidazole derivatives include, but are not limited to, phenylbenzimidazole sulfonic acid (e.g., "Eusolex 232"; manufactured by Merck) and disodium phenyldibenzimidazole tetrasulfonate (e.g., "Neo Heliopan AP"; manufactured by Herman & Reimer).

[0045] Examples of triazine derivatives include, but are not limited to, bisethylhexyloxyphenol methoxyphenyl triazine, ethylhexyl triazone (e.g., "Uvinal T150" manufactured by BASF), diethylhexylbutamido triazone (e.g., "Uvasorb HEB" manufactured by Sigma 3V), and 2,4,6-tris(diisobutyl-4'-aminobenzalmalonate)-s-triazine.

[0046] Examples of phenylbenzotriazole derivatives include, but are not limited to, drometrizole trisiloxane (e.g., Silatrizole, manufactured by Rhodia Chemie) and methylenebis(benzotriazolyltetramethylbutylphenol) (e.g., Tinosorb M, manufactured by Ciba Specialty Chemicals).

[0047] Examples of anthranil derivatives include, but are not limited to, menthyl anthranilate (for example, "Neo Heliopan MA" manufactured by Herman & Reimer).

[0048] Imidazoline derivatives include, but are not limited to, ethylhexyldimethoxybenzylidene dioxoimidazoline propionate and the like.

[0049] Examples of benzalmalonate derivatives include, but are not limited to, polyorganosiloxanes having benzalmalonate functional groups (for example, Polysilicone-15; "Parsol SLX"; manufactured by DSM Nutrition Japan).

[0050] Examples of 4,4-diarylbutadiene derivatives include, but are not limited to, 1,1-dicarboxy(2,2'-dimethylpropyl)-4,4-diphenylbutadiene and the like.

[0051] In the present invention, the polar oil preferably has an IOB value of 0.17 to 0.63. Here, the IOB value is an abbreviation for Inorganic / Organic Balance (Inorganic / Organic Ratio), which is a value representing the ratio of inorganic value to organic value and serves as an index showing the degree of polarity of an organic compound. Specifically, the IOB value is expressed as IOB value = inorganic value / organic value. The "inorganic value" and "organic value" are set according to the type of atom or functional group, such as 20 for one carbon atom in a molecule and 100 for one hydroxyl group. The IOB value of an organic compound can be calculated by integrating the "inorganic values" and "organic values" of all atoms and functional groups in the organic compound (see, for example, "Organic Conceptual Diagram - Fundamentals and Applications" by Yoshio Koda, pp. 11-17, Sankyo Publishing, 1984).

[0052] Examples of such polar oils (IOB value of 0.17 to 0.63) include hexyl laurate (IOB value = 0.17), isononyl isononanoate (IOB value = 0.20), pentaerythrityl tetraethylhexanoate (IOB value = 0.35), diethylhexyl succinate (IOB value = 0.32), dioctyl succinate (IOB value = 0.36), glyceryl diisostearate (IOB value = 0.29), neopentyl glycol dicaprate (IOB value = 0.25), diisostearyl malate (IOB value = 0.28), glyceryl tri-2-ethylhexanoate (triethylhexanoin), and glyceryl tri-2-ethylhexanoate (triethylhexanoin). ) (IOB value=0.35), trimethylolpropane trioctanoate (IOB value=0.33), diisobutyl adipate (IOB value=0.46), N-lauroyl-L-glutamic acid-2-octyldodecyl ester (IOB value=0.29), diisopropyl sebacate (IOB value=0.40), ethylhexyl methoxycinnamate (IOB value=0.28), 2-ethylhexyl ethylhexanoate (IOB value=0.20), PPG-3 dipivalate (IOB value=0.52), and caprylic / capric triglyceride (IOB value=0.33).

[0053] (Other Oils) The composition of the present invention may further contain oils other than the polar oils described above, as long as the effects of the present invention are not impaired. The other oils are not particularly limited, and examples thereof include hydrocarbon oils and silicone oils.

[0054] Specific examples of other oils include, but are not limited to, chain silicone oils such as polydimethylsiloxane, methylphenylpolysiloxane, and methylhydrogenpolysiloxane; cyclic silicone oils such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane; and hydrocarbon oils such as decane, dodecane, isododecane, isohexadecane, liquid paraffin, squalane, squalene, and paraffin.

[0055] The other oil may be a volatile oil or a non-volatile oil.

[0056] In the present invention, when other oils are contained, the content of the other oils in the oil may be, for example, 45% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, or 15% by mass or less.

[0057] <Other Components> In addition to the above-mentioned essential components (a) to (c) and water as a dispersant for the oil, the composition of the present invention may further contain other components to the extent that the effects of the present invention are not impaired. The other components will be described below by way of example.

[0058] (d) Emulsifier The composition of the present invention may further comprise an emulsifier.

[0059] As the emulsifier, for example, hydrophobically modified alkyl cellulose is preferably used, which is generally classified as a "polymer surfactant."

[0060] Here, the hydrophobically modified alkyl cellulose refers to an alkyl cellulose that has been hydrophobically modified with an alkyl group having 14 to 22 carbon atoms. This hydrophobically modified alkyl cellulose is a compound in which a long-chain alkyl group, which is a hydrophobic group, has been introduced into a water-soluble cellulose ether derivative, and is represented by the following general formula (I):

[0061] [wherein R may be the same or different and is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a -[CH ２ CH (CH ３ ) O] ｍ -H (wherein m is an integer of 1 to 5, preferably 1 to 3), a group -CH ２ CH ２ OH and the group —CH ２ CH(OH)CH ２ OR' (wherein R' is an alkyl group having 14 to 22 carbon atoms), but the group -CH ２ CH(OH)CH ２ OR' is always included. A is a group -(CH ２ ) ｑ - (q is an integer of 1 to 3, preferably 1), and n is an integer of 100 to 10,000, preferably 500 to 5,000.

[0062] The method for producing the hydrophobically modified alkyl cellulose of formula (I) generally involves the use of a water-soluble cellulose ether derivative as a base, specifically, methyl cellulose (wherein R is a hydrogen atom or a methyl group), ethyl cellulose (wherein R is a hydrogen atom or an ethyl group), propyl cellulose (wherein R is a hydrogen atom or a propyl group), butyl cellulose (wherein R is a hydrogen atom or a butyl group), hydroxypropyl cellulose (wherein R is a hydrogen atom or a hydroxypropyl group (group -[CH ２ CH (CH ３ ) O] ｍ -H (wherein m is an integer of 1 to 5, preferably 1 to 3)], hydroxypropyl methylcellulose (wherein R is a hydrogen atom, a methyl group, or a hydroxypropyl group (same as above)), or the like, can be contacted with a compound for introducing a long-chain alkyl group having 14 to 22 carbon atoms, specifically, a long-chain alkyl glycidyl ether of the following formula (II), in the presence of an alkali catalyst.

[0063] [wherein R' is an alkyl group having 14 to 22 carbon atoms.]

[0064] The group —CH introduced into the hydrophobically modified alkyl cellulose of the present invention ２ CH(OH)CH ２ The OR' content is preferably about 0.1 to 5.0% by mass based on the total hydrophobically modified alkyl cellulose. To achieve this content, the molar ratio of the water-soluble cellulose ester derivative and the long-chain alkyl glycidyl ether in the reaction, the reaction time, the type of alkali catalyst, and other factors may be appropriately selected. After the reaction, the reaction product may be subjected to purification steps such as neutralization, filtration, washing, drying, and sieving.

[0065] Among the above water-soluble cellulose ether derivatives, it is particularly preferable to select hydroxypropylmethylcellulose (wherein R in formula (I) is a hydrogen atom, a methyl group, a -[CH ２ CH (CH ３ ) O] ｍ H and the group —CH ２ CH(OH)CH ２ OR', and q of the group A is 1, and A is a methylene group).

[0066] Furthermore, R' in the long-chain alkyl glycidyl ether of formula (II) is an alkyl group having 14 to 22 carbon atoms, preferably an alkyl group having 14 to 20 carbon atoms, and more preferably a stearyl group having 18 carbon atoms (-C １８ H ３７ If the alkyl group R′ has less than 14 carbon atoms or 23 or more carbon atoms, the emulsion stability of the resulting hydrophobically modified alkyl cellulose will be insufficient.

[0067] The weight average molecular weight of the hydrophobically modified alkyl cellulose is preferably 100,000 to 1,000,000, more preferably 300,000 to 800,000, and even more preferably 550,000 to 750,000.

[0068] In the present invention, the hydrophobically modified alkyl cellulose is preferably hydrophobically modified hydroxypropyl methyl cellulose (hydrophobized hydroxypropyl methyl cellulose), more specifically, stearoxy hydroxypropyl cellulose. Alternatively, commercially available products may be used as the hydrophobically modified alkyl cellulose.

[0069] When the composition of the present invention contains an emulsifier, the content thereof is not particularly limited and may be, for example, 0.05% by mass or more, 0.10% by mass or more, 0.15% by mass or more, or 0.20% by mass or more, and may be 1.0% by mass or less, 0.50% by mass or less, or 0.30% by mass or less.

[0070] (e) Aqueous Phase Thickener The composition of the present invention may further contain an aqueous phase thickener. Blending an aqueous phase thickener into the aqueous phase, particularly using it in combination with the above-mentioned emulsifier, is preferred from the viewpoint of increasing the blending ratio of the ultraviolet scattering agent and the ultraviolet absorber while suppressing the blending amount of oil.

[0071] Here, the aqueous phase thickener is a thickener that has the function of thickening the aqueous phase, and may be one that, in particular, causes a decrease in viscosity in the presence of electrolytes at concentrations within the range generally incorporated into cosmetics. Furthermore, in the present invention, such aqueous phase thickeners that cause a decrease in viscosity due to an increase in electrolyte concentration are also referred to as "aqueous phase thickeners with low salt tolerance." Such thickeners with low salt tolerance may be selected from water-soluble thickeners that have traditionally been incorporated into cosmetics and the like for the purpose of adjusting the viscosity of the aqueous phase.

[0072] Specific examples of aqueous phase thickeners include, but are not limited to, vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl methyl ether, polyvinylpyrrolidone, vinylpyrrolidone and vinyl acetate copolymers, and carboxyvinyl polymers; and acrylic polymers such as sodium polyacrylate, polyethyl acrylate, polyacrylic acid alkanolamine, alkyl methacrylate and dimethylaminoethyl methacrylate copolymers, poly2-acrylamido-2-methylpropanesulfonic acid, polymethacryloyloxytrimethylammonium, (acryloyldimethyltaurate ammonium / VP) copolymer, and dimethylacrylamide / acryloyldimethyltaurate Na crosspolymer.

[0073] However, among thickeners with low salt tolerance, the use of a thickener that forms a water-swellable microgel in the aqueous phase and thickens through friction between the swollen microgel particles is preferable compared to a thickener that thickens through polymer chain entanglement, as this can further suppress stickiness when the cosmetic is applied to the skin. This is because, for example, the hydrophobically modified alkyl cellulose blended as the emulsifier described above also has a thickening effect through polymer chain entanglement, and further blending a thickener that thickens through the same mechanism can promote this thickening effect and cause stickiness.

[0074] In the composition of the present invention, when an aqueous phase thickener is contained, the content thereof is not particularly limited and may be, for example, 0.05% by mass or more, 0.10% by mass or more, 0.15% by mass or more, 0.20% by mass or more, 0.25% by mass or more, or 0.30% by mass or more, and may be 3.0% by mass or less, 2.0% by mass or less, or 1.0% by mass or less.

[0075] In addition to the above-mentioned "other ingredients," the composition of the present invention may contain, for example, glycols such as propylene glycol, dipropylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol; glycerins such as glycerin, diglycerin, and polyglycerin; sugar alcohols such as sorbitol, mannitol, maltitol, xylitol, and erythritol; sugars such as fructose, glucose, galactose, maltose, lactose, and trehalose; natural pigments such as chlorophyll and β-carotene; plant-based polymers such as gum arabic, tragacanth gum, galactan, guar gum, carob gum, karaya gum, gellan gum, and carrageenan; microbial polymers such as xanthan gum, dextran, succinoglucan, and pullulan; and animal-based polymers such as collagen, casein, albumin, and gelatin. starch-based polymers such as carboxymethyl starch and methylhydroxypropyl starch; cellulose-based polymers such as methylcellulose, ethylcellulose, methylhydroxypropyl cellulose, hydroxyethyl cellulose, sodium cellulose sulfate, hydroxypropyl cellulose, sodium carboxymethylcellulose, and crystalline cellulose; alginic acid-based polymers such as sodium alginate and propylene glycol alginate; other thickeners; vitamins such as magnesium ascorbyl phosphate, ascorbyl glucoside, vitamin B6 hydrochloride, and pantothenyl ethyl ether; pharmaceutical agents such as bactericides, anti-inflammatory agents, preservatives, plant extracts, and amino acids; lower alcohols such as ethanol and isopropyl alcohol; aromatic alcohols such as phenoxyethanol and benzyl alcohol; or silica, and other various ingredients that are commonly incorporated into cosmetics.

[0076] Preparation of the Composition of the Present Invention The composition of the present invention can be prepared according to a method commonly used for oil-in-water emulsion cosmetics, i.e., by separately mixing the aqueous phase component and the oil phase component, and emulsifying the aqueous phase component by adding the oil phase component while stirring.

[0077] Cosmetics The composition of the present invention can be suitably used as a cosmetic or a raw material thereof. That is, the present invention particularly provides a cosmetic composition, more particularly a sunscreen cosmetic composition.

[0078] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these. In the following, unless otherwise specified, the contents are expressed in mass %.

[0079] Compositions of Examples and Comparative Examples were prepared according to the formulations shown in the following Tables 1 and 2. The resulting compositions were evaluated as follows.

[0080] 1. Fresh Feeling in Use When the compositions shown in Table 1 (i.e., the compositions of Examples 1 and 2, and Comparative Examples 1 to 5) and the compositions shown in Table 2 (i.e., the compositions of Comparative Examples 6 to 10) were evaluated for fresh feel in use, it was found that the compositions in Table 1 had a more fresh feel in use than the compositions in Table 2. In Tables 1 and 2, compositions with a relatively high fresh feel in use were evaluated as "A," and compositions with a relatively low fresh feel in use were evaluated as "B." It was found that the obtained evaluation results were consistent with the oil ratios of the compositions in Table 1 and Table 2.

[0081] The oil content of each composition shown in Table 1 is 18% by mass, while the oil content of each composition shown in Table 2 is 28% by mass.

[0082] 2. Evaluation of Whiteness Each composition of the Examples and Comparative Examples was applied to an S-plate (a 5 x 5 cm V-grooved PMMA plate, SPFMASTER-PA01, manufactured by Shiseido Medical Technology Co., Ltd.) and dried, after which the absorbance of transmitted light in the visible light region (401 to 500 nm) was measured, and the results are shown in Tables 1 and 2. Note that all of the obtained absorbance values ​​were values ​​obtained by subtracting the absorbance of a blank, and in these tables, the absorbance of each Example and Comparative Example using a different type of dispersant was evaluated based on the absorbance of Comparative Examples 1, 2, and 6, which did not use a dispersant.

[0083] More specifically, if the absorbance in the visible light region of the composition to be evaluated is smaller than the absorbance in the visible light region of the reference composition, this suggests that the problem of noticeable whiteness due to the UV scattering agent after application to the skin has been alleviated, and this is indicated as "A" in Tables 1 and 2. If the absorbance in the visible light region of the composition to be evaluated is larger than the absorbance in the visible light region of the reference composition, this suggests that the problem of noticeable whiteness due to the UV scattering agent after application to the skin has not been alleviated, and this is indicated as "B" in Tables 1 and 2.

[0084] In Tables 1 and 2, the composition of Comparative Example 1 was used as the "reference composition" to evaluate the composition of Example 1, the composition of Comparative Example 2 was used as the "reference composition" to evaluate the compositions of Example 2 and Comparative Examples 3 to 5, and the composition of Comparative Example 6 was used as the "reference composition" to evaluate Comparative Examples 6 to 10. The same applies to "3. Evaluation of UV protection effect" described below.

[0085] 3. Evaluation of UV Protection Effect The compositions of the Examples and Comparative Examples were applied to an S-plate (a 5 x 5 cm V-grooved PMMA plate, SPFMASTER-PA01, manufactured by Shiseido Medical Technology Co., Ltd.) and dried, after which the absorbance in the ultraviolet region (280 to 400 nm) was measured, and the results are shown in Tables 1 and 2. Note that the absorbance values ​​obtained were all values ​​obtained by subtracting the absorbance of a blank, and in these tables, the absorbance of each Example and Comparative Example using a different type of dispersant was evaluated based on the absorbance of Comparative Examples 1, 2, and 6, which did not use a dispersant.

[0086] More specifically, if the absorbance in the ultraviolet region of the composition to be evaluated is greater than that of the reference composition, this suggests an improved UV protection effect, and is marked as "A" in Tables 1 and 2. If the absorbance in the ultraviolet region of the composition to be evaluated is less than that of the reference composition, this suggests a decreased UV protection effect, and is marked as "B" in Tables 1 and 2.

[0087]

[0088]

[0089] As is clear from Tables 1 and 2, the compositions of Examples 1 and 2 have both a fresh feel when used and a high UV protection effect, and have improved the problem of noticeable whiteness caused by the UV scattering agent after application to the skin.

[0090] In contrast, the compositions of Comparative Examples 6 to 10 were found to have a relatively weaker fresh feeling when used compared to the compositions of Examples 1 and 2.

[0091] Furthermore, the results of Comparative Examples 6 to 10 shown in Table 2 indicate that when the ratio of the UV scattering agent to the oil content is not relatively high (54 parts by mass per 100 parts by mass of oil content) and the ratio of the polar oil to the oil content is not relatively high (46% by mass of the oil content is polar oil), the improvement in the whiteness problem by polyhydroxystearic acid is comparable to that of other dispersants. In other words, in the configurations of Comparative Examples 6 to 10, no specificity was observed in the improvement in the whiteness problem by polyhydroxystearic acid.

[0092] <Formulation Examples> Formulation examples of cosmetics using the composition of the present invention are given below, but the present invention is not limited to these exemplary formulation examples.

[0093]

[0094]

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[0098]

Claims

1. An oil-in-water emulsion composition, particularly a cosmetic composition, comprising the following components (a) to (c): (a) an ultraviolet scattering agent, (b) polyhydroxystearic acid, and (c) oil, The ultraviolet scattering agent is dispersed in the oil, The ultraviolet scattering agent is 50 parts by mass or more relative to 100 parts by mass of the oil content, and 55% by mass or more of the oil content is polar oil, composition.

2. The composition according to claim 1 , wherein the content of the ultraviolet scattering agent is 5.0 mass % or more.

3. The composition according to claim 1 , wherein the oil content is 20% by mass or less.

4. The composition according to claim 1 , wherein the polyhydroxystearic acid is present in an amount of 3.0 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the ultraviolet scattering agent.

5. The composition of claim 1 , wherein the polar oil is 80% by mass or more of the oil content.

6. The composition of claim 1 , wherein the polar oil comprises an ultraviolet light absorber.

7. The composition of claim 1 further comprising (d) an emulsifier.

8. The composition of claim 1 further comprising: (e) an aqueous phase thickener.

9. The composition according to any one of claims 1 to 8, which is a sunscreen cosmetic composition.