JP2024095537A - Oil-in-water type emulsion composition - Google Patents

Abstract

To provide an oil-in-water type emulsion composition having excellent stability over time and fresh and smooth spreading at the time of application while having a high ultraviolet protection effect and water resistance and comprising a cellulose nanofiber, a liquid oil containing an oil-soluble ultraviolet absorbent, a hydrophobically treated particulate metal oxide, a nonionic surfactant and a specific salt-resistant water-soluble polymer in which the content of the nonionic surfactant is set within a specific range.SOLUTION: There is provided an oil-in-water type emulsion composition which comprises the following components (A) to (E): (A) a cellulose nanofiber, (B) a liquid oil containing an oil-soluble ultraviolet absorbent, (C) a hydrophobically treated particulate metal oxide, (D) 0.2 to 2.5 mass% of a nonionic surfactant and (E) one or two or more salt-resistant water-soluble polymers selected from a polyacrylamide-based compound and an ester copolymer of a (meth)acrylic acid-(meth)acrylic acid alkyl ester and a (meth)acrylic acid (polyoxyethylene monoalkyl ether).SELECTED DRAWING: None

Description

The present invention relates to an oil-in-water emulsion composition.

In recent years, compositions with various functions and usability (usage sensation) have been developed, among which oil-in-water emulsion compositions are widely used in creams and milky lotions because of their excellent usability, such as a high moisturizing feeling and a fresh feeling to the touch. In addition, oil-in-water emulsion compositions with various functions have been developed so far, and for example, oil-in-water emulsion compositions having a high ultraviolet protection effect that protects the skin from UVA (long-wavelength ultraviolet rays with wavelengths of 320 to 400 nm) and UVB (medium-wavelength ultraviolet rays with wavelengths of 290 to 320 nm), and oil-in-water emulsion compositions having an ultraviolet protection effect and also excellent water resistance so that the cosmetic film is not washed off by water, sweat, etc., assuming various usage scenes, have been reported.
However, in order to achieve satisfactory UV protection effect and water resistance, appropriate selection of UV protection agent, polymer and oil is required, but depending on the type and content, there is concern that the emulsion state becomes unstable over time, and the feeling of use such as poor spreadability and stickiness may decrease. Up to now, as a technology that has UV protection effect and is excellent in feeling of use, for example, an oil-in-water emulsion composition containing (meth) alkyl acid / (meth) acrylate alkyl / (meth) acrylate POE monoalkyl ester copolymer, UV protection agent, nonionic surfactant, higher alcohol (see, for example, Patent Document 1) has been proposed. In addition, as a technology that has UV protection effect and is excellent in water resistance, for example, an oil-in-water emulsion composition containing a liquid oil agent containing an oil-soluble organic UV absorber, a salt-resistant water-soluble polymer, and a hydrophobized fine metal oxide powder, and in which the content and ratio of a specific component are controlled (see, for example, Patent Document 2) has been proposed. Furthermore, as a technology for suppressing dryness and stickiness while having an ultraviolet protection effect, for example, a sunscreen cosmetic composition that contains cellulose nanofibers that satisfy specific conditions, an ultraviolet scattering agent, and a water-miscible organic solvent (see, for example, Patent Document 3) has been proposed.

International Publication No. 2018/221606 JP 2019-94280 A JP 2017-109986 A

However, the technology disclosed in Patent Document 1 may not have sufficient long-term high-temperature stability, and water resistance has not been considered.
In the technique disclosed in Patent Document 2, there are cases where the fresh and smooth spreading of the cosmetic upon application is insufficient.
In the technology disclosed in Patent Document 3, the fresh and smooth spreadability upon application and stability over time were sometimes insufficient. In addition, water resistance was not considered.

Oil-in-water emulsion compositions having UV protection effects are used in cosmetics for sunscreen applications, such as sunscreens and foundations, and since these cosmetics are used not only on the body but also on the face, many customers are looking for a light finish. In this context, customers prefer a pleasant feel on the skin that does not burden the skin and makes them want to use it repeatedly, and there is a strong demand for a fresh, smooth spread when applied.
Therefore, an object of the present invention is to provide an oil-in-water emulsion composition which has high UV protection effect and water resistance, while also exhibiting excellent stability over time, and which further has excellent fresh, smooth spreadability upon application.

In order to achieve a high UV protection effect, it is necessary to incorporate a large amount of UV protection factors. In oil-in-water emulsion compositions containing these UV protection factors, salt-resistant water-soluble polymers are used to ensure stability. However, conventional techniques using salt-resistant water-soluble polymers have not been able to realize a satisfactory fresh and smooth spread when applied. Thus, through extensive research, the inventors have found that good usability can be realized by including cellulose nanofibers. However, with oil-in-water emulsion compositions containing cellulose nanofibers, the stability over time deteriorates, making it difficult to ensure stability.

The inventors further conducted extensive research and found that by containing a specific amount of a nonionic surfactant and a polyacrylamide compound, as well as one or more salt-resistant water-soluble polymers selected from (meth)acrylic acid, (meth)acrylic acid alkyl esters, and (meth)acrylic acid (polyoxyethylene monoalkyl ether) ester copolymers, the composition is stable at high temperatures while providing excellent fresh, smooth spreadability upon application and a good feel upon use. Furthermore, the oil-in-water emulsion composition of the present invention exhibited high water resistance, even though it contained a surfactant that reduces water resistance. This is believed to be because the high film-forming properties of the cellulose nanofibers cause phase separation upon application, resulting in the formation of a highly uniform coating film.

In addition, in oil-in-water emulsion compositions, linear saturated alcohols are often used for the purpose of improving stability. However, surprisingly, in the present invention, when a certain amount or more of linear saturated alcohol is blended, the emulsion state becomes unstable and stability over time cannot be guaranteed. This was a new problem that was not known before. In view of this situation, the present inventors conducted further intensive research and found that an oil-in-water emulsion composition containing cellulose nanofibers, a liquid oil containing an oil-soluble UV absorber, a hydrophobized metal oxide fine particle, a specific amount of a nonionic surfactant, a polyacrylamide compound, and one or more salt-resistant water-soluble polymers selected from (meth)acrylic acid, (meth)acrylic acid alkyl esters, and (meth)acrylic acid (polyoxyethylene monoalkyl ether) ester copolymers has excellent UV protection effect and stability over time, while also spreading smoothly and moistly when applied and having excellent water resistance, and has completed the present invention.

That is, the present invention provides the following:
[1]
The following components (A) to (E):
(A) Cellulose nanofibers (B) Liquid oil containing an oil-soluble UV absorber (C) Hydrophobically treated metal oxide particles (D) Nonionic surfactant 0.2 to 2.5% by mass
(E) An oil-in-water emulsion composition containing a polyacrylamide compound and one or more salt-tolerant water-soluble polymers selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid alkyl esters, and (meth)acrylic acid (polyoxyethylene monoalkyl ether) ester copolymers.
[2]
The oil-in-water emulsion composition according to [1], wherein the content of the component (A) is 0.05 to 1 mass %.
[3]
The oil-in-water emulsion composition according to [1] or [2], wherein the component (D) contains at least a polyglycerol fatty acid ester, and the content of the polyglycerol fatty acid ester in the component (D) is 50 mass% or more.
[4]
The oil-in-water emulsion composition according to [1] or [2], wherein a content mass ratio (E)/(A) of the component (E) to the component (A) is 0.1 to 8.
[5]
The oil-in-water emulsion composition according to [1] or [2], characterized in that it is substantially free of linear saturated alcohols.
[6]
The oil-in-water emulsion composition according to [1] or [2], wherein the component (D) contains at least two kinds of nonionic surfactants having different HLBs, and the weighted average HLB value of the nonionic surfactants is 10 to 15.
[7]
The oil-in-water emulsion composition according to [1] or [2] further contains a component (F) an inulin fatty acid ester.
[8]
The oil-in-water emulsion composition according to [1] or [2] further contains component (G) silica.
[9]
The oil-in-water emulsion composition according to [1] or [2], wherein the oil-in-water emulsion composition is a cosmetic used for sunscreen purposes.

The oil-in-water emulsion composition of the present invention has a high UV protection effect and excellent water resistance. Furthermore, the oil-in-water emulsion composition of the present invention has excellent stability over time, and also has excellent fresh and smooth spreadability upon application. Note that the effects described here are not necessarily limited, and may be any of the effects described in this specification.

The following describes a preferred embodiment for carrying out the present invention. Note that the embodiment described below is an example of a typical embodiment of the present invention, and the scope of the present invention is not to be interpreted narrowly by this. Furthermore, in this specification, percentages are expressed by mass unless otherwise specified. Furthermore, the upper limit (or less) and the lower limit (or more) of each numerical range (-) can be combined as desired. In this specification, "X-Y" indicating a range includes X and Y and means "X or more and Y or less."

<Component (A) Cellulose Nanofiber>
The cellulose nanofibers (component (A)) used in the present invention are produced by pulverizing fibrous cellulose or its derivatives to a size of 3 to 1000 nm. In the present invention, component (A) is not particularly limited as long as the average fiber diameter is 3 to 1000 nm, and the average fiber diameter is preferably 3 to 500 nm, more preferably 3 to 250 nm, and even more preferably 3 to 150 nm. The average fiber diameter is determined by measuring the diameter and fiber length of 20 fibers of cellulose or its derivatives dispersed in water using an electron microscope image, and calculating the arithmetic average value of the measured values.

The method for refining component (A) is not particularly limited, but examples include mechanical disintegration using a high-pressure homogenizer or ball mill, chemical disintegration using an N-oxyl compound such as 2,2,6,6-tetramethylpiperidine (TEMPO) to oxidize and refining cellulose, and biological disintegration using enzymes such as cellulase. Among these, the chemical disintegration method is preferred because the carboxyl groups generated by the oxidation of hydroxyl groups in cellulose during the oxidation reaction contribute to improving impact resistance. The origin of natural cellulose is not particularly limited, and examples include those biosynthesized by plants, animals, and microorganisms.

Examples of cellulose derivatives include TEMPO oxidized cellulose, carboxymethylated cellulose, cellulose phosphate, cellulose phosphite, sulfonated cellulose, and cellulose sulfate.

In the present invention, TEMPO oxidized cellulose and carboxymethylated cellulose are preferred from the viewpoints of stability over time and fresh, smooth spreadability upon application.

In component (A), commercially available products of TEMPO oxidized cellulose include Leolista C-2SP (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Leolista C-2EP (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and Cellenpia TC-01A (manufactured by Oji Paper Co., Ltd.), a commercially available product of carboxymethylated cellulose includes Cellenpia CS-01C (manufactured by Oji Paper Co., Ltd.), a commercially available product of phosphated cellulose includes AUROVISCO (manufactured by Oji Holdings Co., Ltd.), a commercially available product of phosphite esterified cellulose includes ELLEX-☆ (Daioh Paper Co., Ltd.), and an example of unmodified cellulose includes ELLEX-S (Daioh Paper Co., Ltd.).

In the present invention, the content of component (A) is preferably 0.05% by mass (hereinafter abbreviated as "%)" or more as a lower limit, and more preferably 0.1% or more, from the viewpoint of stability over time, etc. Also, from the viewpoint of fresh and smooth spreading when applied, etc., it is preferably 1% or less, more preferably 0.8% or less, and even more preferably 0.5% or less. Also, 0.05 to 1% is preferable, 0.1 to 0.8% is more preferable, and 0.1 to 0.5% is even more preferable. By setting it in this range, it is more preferable because it has excellent UV protection effect, water resistance, stability over time, and fresh and smooth spreading when applied.

<Component (B): Liquid oil containing an oil-soluble ultraviolet absorber>
The liquid oil containing the oil-soluble UV absorber (B) used in the present invention is a liquid oil containing an oil-soluble UV absorber, and the oil-soluble UV absorber is not particularly limited as long as it is a water-insoluble UV absorber. Here, the term "liquid" refers to a liquid having a viscosity of 7000 mPa·s or less when measured at 25°C and 1 atmospheric pressure using a B-type viscometer (rotor No. 2).

The liquid oil of component (B) is not particularly limited as long as it is one that is generally used in cosmetics and the like, but examples thereof include hydrocarbons such as isododecane, isohexadecane, light isoparaffin, liquid paraffin (mineral oil), squalane, squalene, α-olefin oligomer, polybutene, liquid isoparaffin, heavy liquid isoparaffin, polyisobutylene, and hydrogenated polyisobutene; rapeseed oil, avocado oil, almond oil, apricot kernel oil, perilla oil, orange oil, olive oil, kiwi seed oil, sesame oil, wheat germ oil, rice germ oil, rice bran oil, safflower oil, sage oil, soybean oil, tea seed oil, corn oil, rapeseed oil, evening primrose oil, camellia oil, persic oil, pearl barley oil, peanut oil, sunflower oil, grape seed oil, and the like. oil, meadowfoam oil, rosemary oil, jojoba oil, macadamia nut oil, lavender oil, rosehip oil, mink oil and other animal and vegetable oils; glyceryl tri-2-ethylhexanoate, isotridecyl isononanoate, isononyl isononanoate, cetyl 2-ethylhexanoate, diethylhexyl succinate, isopropyl myristate, isopropyl palmitate, 2-ethylhexyl palmitate, octyldodecyl myristate, glyceryl trioctanoate, tri(capryl/capric acid)glyceryl, glyceryl diisostearate, glyceryl triisostearate, propylene glycol dicaprate, neopentyl glycol dicaprate, diisostearyl malate, neopentyl glycol diethylhexanoate , pentaerythritol tetraisostearate, pentaerythritol tetra-2-ethylhexanoate, dipentaerythritol pentaisostearate, dialkyl carbonate, bisethoxydiglycol cyclohexane-1,4-dicarboxylate, dimer dilinoleyl hydrogenated rosin condensate, alkyl benzoate (C12-15) and other esters; fatty acids such as oleic acid and isostearic acid; polymers of fatty acids such as polyhydroxystearic acid; higher alcohols such as oleyl alcohol, 2-octyldodecanol, 2-decyltetradecanol, isostearyl alcohol, and 2-hexyldecanol; dimethylpolysiloxane (dimethicone), methyltrimethicone, methylphenylpolysiloxane, octamethylcyclotetramethicone ... Examples of the silicone oils include lasiloxane, decamethylcyclopentasiloxane, tetramethyltetrahydrogencyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, tetramethyltetratrifluoropropylcyclotetrasiloxane, pentamethylpentatrifluoropropylcyclopentasiloxane, polyether-modified methylpolysiloxane, oleyl-modified methylpolysiloxane, and polyvinylpyrrolidone-modified methylpolysiloxane; fluorine-based oils such as perfluoropolyether, perfluorodecane, and perfluorooctane; lanolin derivatives such as lanolin acetate, lanolin fatty acid isopropyl, and lanolin alcohol; and the like. One or more of these can be used.

In the present invention, the liquid oil of component (B) is preferably a hydrocarbon oil and/or an ester oil, and more preferably a hydrocarbon oil and an ester oil, from the viewpoint of excellent solubility of the oil-soluble UV absorber and optimally exhibiting the UV protection effect and stability over time. Among them, the hydrocarbon oil is preferably one or more selected from the group consisting of isododecane, isohexadecane, light isoparaffin, liquid paraffin (mineral oil), squalane, squalene, α-olefin oligomer, polybutene, liquid isoparaffin, heavy liquid isoparaffin, polyisobutylene, and hydrogenated polyisobutene, and isododecane is more preferred. The ester oil is preferably one or more selected from the group consisting of isononyl isononanoate, isotridecyl isononanoate, cetyl 2-ethylhexanoate, propylene glycol dicaprate, alkyl benzoate (C12-15), isopropyl adipate, PG di(caprylate/caprate), dibutyl adipate, and diethylhexyl succinate, and more preferably one or more selected from the group consisting of isononyl isononanoate, cetyl 2-ethylhexanoate, and alkyl benzoate (C12-15).

The oil-soluble UV absorber contained in component (B) is not particularly limited as long as it is one that is generally used in cosmetics, etc., and may be in any form of solid, paste, or liquid. Specifically, for example, ethylhexyl methoxycinnamate, ethoxyethyl methoxycinnamate, isopropyl methoxycinnamate/diisopropyl cinnamate mixture, methyl bis(trimethylsiloxy)silylisopentyl trimethoxycinnamate, amyl paradimethylamino acid benzoate, 2-ethylhexyl paradimethylamino acid benzoate, ethylene glycol salicylate, ethylhexyl salicylate, benzyl salicylate, homomenthyl salicylate, octocrylene, dimethyldiethylbenzalmalonate, dimethoxybenzylidene. Examples of suitable hydroxybenzoyl compounds include 2-ethylhexyl dioxoimidazolidinepropionate, diethylaminohydroxybenzoylhexyl benzoate, 2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]-1,3,5-triazine, drometrizole trisiloxane, 4-tert-butyl-4'-methoxydibenzoylmethane, and 2-hydroxy-4-methoxybenzophenone. Among these, it is preferable to use one or more selected from ethylhexyl methoxycinnamate, ethylhexyl salicylate, dimethyl diethyl benzal malonate, diethylamino hydroxybenzoyl hexyl benzoate, 2,4-bis {[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4,6-tris [4-(2-ethylhexyloxycarbonyl) anilino]-1,3,5-triazine, and drometrizole trisiloxane, and it is more preferable to use one or more selected from ethylhexyl methoxycinnamate, ethylhexyl salicylate, dimethyl diethyl benzal malonate, diethylamino hydroxybenzoyl hexyl benzoate, and 2,4-bis {[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine.

Furthermore, from the viewpoint of UV protection effect, etc., it is more preferable that the oil-soluble UV absorber of component (B) is three or more types selected from ethylhexyl methoxycinnamate, ethylhexyl salicylate, dimethyl diethyl benzalmalonate, diethylamino hydroxybenzoyl hexyl benzoate, and 2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine, and even more preferable that it is four or more types. Here, the combination of three or four types is not particularly limited. For example, in the case of three types, the combination may be: [1] a combination of ethylhexyl methoxycinnamate, ethylhexyl salicylate, and dimethyl diethyl benzal malonate; [2] a combination of ethylhexyl methoxycinnamate, ethylhexyl salicylate, and diethylamino hydroxybenzoyl hexyl benzoate; [3] a combination of ethylhexyl methoxycinnamate, ethylhexyl salicylate, and 2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine; [4] a combination of ethylhexyl salicylate, diethylamino hydroxybenzoyl hexyl benzoate, and dimethyl diethyl benzal malonate; [5] a combination of ethylhexyl salicylate, diethylamino hydroxybenzoyl hexyl benzoate, 2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy] -phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine; [6] dimethyldiethylbenzalmalonate, diethylaminohydroxybenzoylhexyl benzoate, 2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine; [7] ethylhexyl methoxycinnamate, diethylaminohydroxybenzoylhexyl benzoate, 2,4 -bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine, and the like. Preferred is the combination of [7] ethylhexyl methoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate, and 2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine. In the case of four types, the combination of [1]' ethylhexyl methoxycinnamate, dimethyl diethyl benzal malonate, diethylamino hydroxybenzoyl hexyl benzoate, and 2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine, [2]' ethylhexyl salicylate, dimethyl diethyl benzal malonate, diethylamino hydroxybenzoyl hexyl benzoate, and 2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine, Examples of suitable combinations include a combination of [3]' ethylhexyl methoxycinnamate, ethylhexyl salicylate, diethylamino hydroxybenzoyl hexyl benzoate, and 2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine, and a combination of [3]' ethylhexyl methoxycinnamate, ethylhexyl salicylate, diethylamino hydroxybenzoyl hexyl benzoate, and 2,4-bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine. The preferred combinations are [1]' or [2]'.

In terms of UV protection effect, the content of component (B) in the present invention is preferably 5% or more as a lower limit, more preferably 10% or more, and even more preferably 12% or more. From the viewpoint of stability over time, the upper limit is preferably 30% or less, more preferably 25% or less, and even more preferably 23% or less. The content of component (B) is preferably 5 to 30%, more preferably 10 to 25%, and even more preferably 12 to 23%. This range is more preferable because it provides excellent UV protection effect, water resistance, stability over time, and fresh, smooth spread when applied.

In the present invention, the content of the oil-soluble UV absorber in component (B) is preferably 20% or more as a lower limit from the viewpoint of UV protection effect, more preferably 30% or more, even more preferably 40% or more, and even more preferably 50% or more. In addition, from the viewpoint of stability over time, the upper limit is preferably 100% or less, more preferably 80% or less, and even more preferably 60% or less. The content of the oil-soluble UV absorber in component (B) is preferably 20 to 100%, more preferably 30 to 80%, even more preferably 40 to 60%, and even more preferably 50 to 60%. This range is more preferable because it provides excellent UV protection effect, water resistance, stability over time, and fresh and smooth spread when applied.

<Component (C): Hydrophobically Treated Metal Oxide Fine Particles>
The hydrophobized fine particle metal oxide of component (C) used in the present invention has its surface coated with a hydrophobizing agent to improve its dispersibility in an oil phase.

The fine particle metal oxide of the present invention is a metal oxide that blocks ultraviolet rays over a wide range from UVB to UVA (290 to 400 nm) by absorbing, scattering, reflecting, extinguishing, etc. In particular, from the viewpoint of a high ultraviolet blocking effect, the metal oxide is preferably one or more selected from zinc oxide, titanium oxide, and cerium oxide, more preferably zinc oxide and/or titanium oxide, and even more preferably zinc oxide.

The shape of the metal oxide is not particularly limited, but examples include granular, spherical, spindle-shaped, plate-shaped, dendritic, balloon-shaped, etc., and from the viewpoints of reducing white cast due to improved dispersibility in the formulation, ultraviolet protection effect, and water resistance, granular, spherical, spindle-shaped, and plate-shaped shapes are preferred.

The metal oxide is not particularly limited, but from the viewpoint of ultraviolet protection effect and water resistance, the average particle size is preferably 500 nm or less, more preferably 3 nm to 100 nm, and even more preferably 5 nm to 50 nm. In the present invention, the average particle size can be measured as the average particle size by image analysis of a transmission electron microscope image.
Approximately 10 mg of the sample is thoroughly dispersed in 1-propanol on a glass slide to obtain a dispersion. The dispersion is stretched to obtain a thin-film sample. The thin film of the sample is placed on a mesh for transmission electron microscope (TEM) measurement with a support film attached. The mesh (dried coating film) is set in a transmission electron microscope (S-4800, Hitachi High-Technologies Corporation) and observed to obtain an image of the dried coating film showing individual particles. The image of the dried coating film surface is processed using an image analysis type particle size distribution analyzer (Mac-View, Mountec Co., Ltd.) with 1,000 particles measured, and the particle size is measured.
This makes it possible to obtain the average particle diameter D50 of the sample (powder) by image analysis of a transmission electron microscope (TEM) image.

The hydrophobic treatment agent of component (C) is not particularly limited as long as it is one that is normally used in cosmetics, quasi-drugs, pharmaceuticals, etc., but examples include silicone treatment agents, fluorine treatment agents, organic titanate treatment agents, fatty acid treatment agents, lecithin treatment agents, amino acid treatment agents, and acylamino acid treatment agents. Among these, from the viewpoint of water resistance and stability over time, it is preferable to use one or more types selected from silicone treatment agents and organic titanate treatment agents, more preferably one or two or more types selected from trialkoxyalkylsilane, alkyl titanate, dimethylpolysiloxane, and methylhydrogenpolysiloxane, and more preferably one or two or more types selected from triethoxycaprylylsilane, isopropyl titanium triisostearate, dimethylpolysiloxane, and methylhydrogenpolysiloxane.

Examples of silicone treatment agents include hydrogen-modified silicones such as methylhydrogenpolysiloxane, chain silicones such as dimethylpolysiloxane, methylpolysiloxane, and methylphenylpolysiloxane, modified silicones such as amino-modified silicone, alkyl-modified silicone, and alkoxy-modified silicone, silicone resins such as trimethylsiloxysilicic acid and acrylic-silicone graft copolymer, silicone rubbers, partially or fully crosslinked organopolysiloxanes, silylating agents, and silane coupling agents, and one or more selected from the group consisting of these can be used. Among these, from the viewpoint of ultraviolet protection effect and stability over time, it is more preferable to use one or more selected from the group consisting of hydrogen-modified silicones, chain silicones, and silane coupling agents, and it is more preferable that the hydrogen-modified silicones are methylhydrogenpolysiloxane, and the chain silicones are dimethylpolysiloxane. The silane coupling agent is not particularly limited, but trialkoxyalkylsilane is preferable. A trialkoxyalkylsilane is a compound in which three alkoxy groups and one alkyl group are bonded to a silicon atom, and the alkoxy groups react with hydroxyl groups and the like on the powder surface to chemically modify the powder surface. In the trialkoxyalkylsilane, the alkoxy group is preferably an alkoxy group having 1 to 3 carbon atoms, such as methoxy, ethoxy, propoxy, etc. In addition, in the trialkoxyalkylsilane, the alkyl group is preferably an alkyl group having 6 to 18 carbon atoms, such as hexyl, octyl, decyl, octadecyl, etc. Examples of such trialkoxyalkylsilanes include trimethoxyhexylsilane, trimethoxyoctylsilane, trimethoxydecylsilane, trimethoxyoctadecylsilane, triethoxyhexylsilane, triethoxyoctylsilane, triethoxydecylsilane, and triethoxyoctadecylsilane. Among these, from the viewpoints of ultraviolet protection effect, stability over time, and water resistance, it is more preferable to use one or more selected from the group consisting of trimethoxyoctylsilane and triethoxyoctylsilane.

Organic titanate treatment agents include alkyl titanates of long-chain carboxylic acid type, pyrophosphate type, phosphorous acid type, amino acid type, etc., and alkyl titanates having an alkyl group with 8 to 24 carbon atoms are preferred. Specific examples of the alkyl titanate include long-chain carboxylic acid type alkyl titanates such as isopropyl triisostearoyl titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl isostearoyl diacryl titanate, and diisostearoyl ethylene titanate, and examples of pyrophosphate type alkyl titanates include tetraisopropyl bis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphat) titanate, and Examples of the phosphorous-type alkyl titanates include isopropyl tri(dioctylpyrophosphate) titanate, bis(dioctylpyrophosphate)oxyacetate titanate, and bis(dioctylpyrophosphate)ethylene titanate. Examples of the amino acid-type alkyl titanates include isopropyl tri(N-amidoethyl aminoethyl) titanate. In the present invention, among these alkyl titanates, from the viewpoints of ultraviolet protection effect, stability over time, and water resistance, long-chain carboxylic acid-type alkyl titanates are preferred, and isopropyl triisostearoyl titanate is more preferred.

The method of hydrophobization treatment for component (C) is not particularly limited, and can be produced by a commonly known method. For example, the hydrophobization agent and powder particles to be treated are added to a solvent, stirred in a ball mill or the like, dried as necessary, washed with water, and filtered repeatedly to remove impurities, and then dried and pulverized to obtain the desired hydrophobized powder. In addition, several types of compounds that are surface treatment agents can be surface-treated simultaneously, or one compound can be used for surface treatment beforehand, and then another compound can be used for surface treatment.

The mass of the hydrophobic treatment agent in component (C) is not particularly limited, but from the viewpoints of UV protection effect, water resistance, and stability over time, the upper limit is preferably 60% or less, more preferably 50% or less, and even more preferably 30% or less, relative to the powder mass before treatment, and the lower limit is preferably 10% or more, more preferably 12% or more, and even more preferably 15% or more.

In the present invention, the content of component (C) is preferably 5% or more as a lower limit, and more preferably 8% or more, from the viewpoint of ultraviolet protection effect, etc. Also, from the viewpoint of fresh and smooth spreading when applied, the content is preferably 20% or less as an upper limit, more preferably 15% or less, and even more preferably 12% or less. Also, the content of component (C) is preferably 5 to 20%, more preferably 5 to 15%, and even more preferably 8 to 12%. This range is more preferable because it provides excellent ultraviolet protection effect, water resistance, stability over time, and fresh and smooth spreading when applied.

<Component (D) Nonionic Surfactant>
The component (D) nonionic surfactant used in the present invention is not particularly limited as long as it is one that is normally used in cosmetics.Specific examples include polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, polyoxyethylene glycol fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene hydrogenated castor oil, fatty acid ester, polyoxyethylene fatty acid ethanolamide, polyoxyalkylene modified silicone, polyoxyalkylene alkyl co-modified silicone, etc.In the present invention, from the viewpoint of ensuring sufficient water resistance, it is preferable to use one or more selected from polyoxyethylene hydrogenated castor oil, polyglycerin fatty acid ester, and sorbitan fatty acid ester.

Examples of polyoxyethylene hydrogenated castor oil include polyoxyethylene hydrogenated castor oil (10 E.O.) (HLB: 6.5), polyoxyethylene hydrogenated castor oil (40 E.O.) (HLB: 12.5), polyoxyethylene hydrogenated castor oil (60 E.O.) (HLB: 14.0), polyoxyethylene hydrogenated castor oil (80 E.O.) (HLB: 15.0), and polyoxyethylene hydrogenated castor oil isostearate (50 E.O.) (HLB: 12.0). Of these, polyoxyethylene hydrogenated castor oil (10 E.O.) (HLB: 6.5) and polyoxyethylene hydrogenated castor oil (80 E.O.) (HLB: 15.0) are preferred.
Polyglycerol fatty acid esters are compounds in which at least a portion of the hydroxyl groups of polyglycerol, such as diglycerol, triglycerol, tetraglycerol, hexaglycerol, and decaglycerol, is esterified with a fatty acid. Examples of fatty acids to be esterified in the polyglycerol fatty acid ester of component (D) include lauric acid, myristic acid, palmitic acid, isopalmitic acid, stearic acid, isostearic acid, oleic acid, behenic acid, linoleic acid, linolenic acid, and polyricinoleic acid, and examples thereof include polyglyceryl-2 stearate (HLB: 5.0), polyglyceryl-2 oleate (HLB: 5.5), and polyglyceryl-2 isostearate. (HLB: 5.5), Polyglyceryl-2 triisostearate (HLB: 3), Polyglyceryl-4 stearate (HLB: 6), Polyglyceryl-4 oleate (HLB: 6.0), Polyglyceryl-6 tristearate (HLB: 2.5), Polyglyceryl-10 pentastearate (HLB: 3.5), Polyglyceryl-10 pentahydroxystearate (HLB: 3.5), Polyglyceryl-1 pentaisostearate 0 (HLB: 3.5), Polyglyceryl-10 Oleate (HLB: 14.0), Polyglyceryl-10 Laurate (HLB: 16.0), Polyglyceryl-10 Pentaoleate (HLB: 3.5), Decaglyceryl Decastearate (HLB: 3.0), Polyglyceryl-10 Monostearate (HLB: 12.0), Hexaglyceryl Tristearate (HLB: 7), Tetraglyceryl Monostearate (HLB: 6), Monostearate (HLB: 7), Monostearate (HLB: 8), Monostearate (HLB: 9), Monostearate (HLB: 10), Monostearate (HLB: 11), Monostearate (HLB: 12), Monostearate (HLB: 13), Monostearate (HLB: 14), Monostearate (HLB: 15), Monostearate (HLB: 16), Monostearate (HLB: 17), Monostearate (HLB: 18), Monostearate (HLB: 19), Monostearate (HLB: 20), Monostearate (HLB: 21), Monostearate (HLB: 22), Monostearate (HLB: 23), Monostearate (HLB: 24), Monostearate (HLB: 25), Monostearate (HLB: 26), Monostearate (HLB: 27), Monostearate (HLB: 28), Monostearate (HLB: 29), Monostearate (HLB: 30), Monostearate (HLB: 31), Monostearate (HLB: 32), Monostearate (HLB: 33), Monostearate (HLB: 34), Monostearate (HLB: 35), Monostearate (HLB: 36), Monostearate (HLB: 37 Examples of the polyglyceryl monostearate include hexaglyceryl distearate (HLB: 10.5), decaglyceryl distearate (HLB: 11.0), triglyceryl monomyristate (HLB: 12.0), and polyglyceryl monolaurate (HLB: 16.0). Of these, polyglyceryl-10 monostearate (HLB: 12.0), polyglyceryl-10 oleate (HLB: 14.0), and polyglyceryl-10 laurate (HLB: 16.0) are preferred.
Examples of sorbitan fatty acid esters include sorbitan monolaurate (HLB: 8.6), sorbitan monopalmitate (HLB: 6.7), sorbitan monostearate (HLB: 4.7), sorbitan sesquistearate (HLB: 4.2), sorbitan tristearate (HLB: 2.1), sorbitan monoisostearate (HLB: 5.0), sorbitan sesquiisostearate (HLB: 4.5), sorbitan monooleate (HLB: 4.3), sorbitan sesquioleate (HLB: 3.7), and sorbitan trioleate (HLB: 1.7). Of these, sorbitan sesquioleate (HLB: 3.7) is preferred.

In the present invention, it is preferable that component (D) contains at least a polyglycerol fatty acid ester from the viewpoint of fresh and smooth spreading when applied. Furthermore, in the present invention, the content of polyglycerol fatty acid ester in component (D) is preferably 50% or more, more preferably 60% or more, even more preferably 70% or more, and even more preferably 80% or more. This range is more preferable because it provides excellent UV protection effect, water resistance, stability over time, and fresh and smooth spreading when applied.

In the present invention, from the viewpoint of stability over time and water resistance, it is preferable that component (D) contains at least two types of nonionic surfactants with different HLBs, and that the weighted average HLB value of the nonionic surfactants is 10 to 15.

The weighted average HLB value of component (D) in the present invention is preferably 10 or more as a lower limit, more preferably 10.5 or more, and even more preferably 11 or more. The upper limit is preferably 15 or less, more preferably 14.5 or less, even more preferably 14 or less, and even more preferably 13 or less. The weighted average HLB value of component (D) is preferably 10 to 15, more preferably 10.5 to 14.5, even more preferably 10.5 to 14, and even more preferably 11 to 13. This range is more preferable because it provides excellent UV protection effect, water resistance, stability over time, and fresh, smooth spread when applied.

Here, the HLB (hydrophile-lipophile balance) in the present invention is an index showing the balance of hydrophilicity and lipophilicity, and is calculated by the following formula (1) proposed by Oda and Teramura et al.
HLB = "Inorganic value (IV) / Organic value (OV)" x 10 (Equation 1)
(See Yoshio Koda, "Organic Conceptual Diagram - Fundamentals and Applications", pages 11-17, Sankyo Publishing, 1984.)

As mentioned above, it is preferable that component (D) contains at least two types of nonionic surfactants with different HLB. Here, the combination of the two types is not particularly limited, but at least two types selected from polyoxyethylene hydrogenated castor oil, polyglycerin fatty acid ester, and sorbitan fatty acid ester are more preferable, and examples include two types of polyoxyethylene hydrogenated castor oil, two types of polyglycerin fatty acid ester, two types of sorbitan fatty acid ester, a combination of polyoxyethylene hydrogenated castor oil and polyglycerin fatty acid ester, a combination of polyoxyethylene hydrogenated castor oil and sorbitan fatty acid ester, a combination of polyglycerin fatty acid ester and sorbitan fatty acid ester, etc. In the present invention, from the viewpoints of stability over time and water resistance, a combination of two types of polyoxyethylene hydrogenated castor oil, a combination of polyoxyethylene hydrogenated castor oil and polyglycerin fatty acid ester, and a combination of polyglycerin fatty acid ester and sorbitan fatty acid ester are preferred, and from the viewpoints of fresh and smooth spread when applied, a combination of polyoxyethylene hydrogenated castor oil and polyglycerin fatty acid ester, and a combination of polyglycerin fatty acid ester and sorbitan fatty acid ester are more preferred.

In the present invention, the content of component (D) is 0.2% or more as a lower limit, preferably 0.3% or more, and more preferably 0.4% or more, from the viewpoint of stability over time. In addition, from the viewpoint of water resistance and fresh and smooth spreading when applied, the upper limit is 2.5% or less, preferably 2% or less, more preferably 1.5% or less, even more preferably 1% or less, and even more preferably 0.8% or less. In addition, the content of component (D) is 0.2 to 2.5%, preferably 0.2 to 2%, more preferably 0.2 to 1.5%, even more preferably 0.3 to 1%, even more preferably 0.3 to 0.8%, and particularly preferably 0.4 to 0.8%. By setting it in this range, it is more preferable because it is more excellent in UV protection effect, water resistance, stability over time, and fresh and smooth spreading when applied.

<Component (E) One or more salt-resistant water-soluble polymers selected from polyacrylamide compounds, (meth)acrylic acid, (meth)acrylic acid alkyl esters, and (meth)acrylic acid (polyoxyethylene monoalkyl ether) ester copolymers>
Component (E) used in the present invention is one or more salt-resistant water-soluble polymers selected from polyacrylamide compounds and ester copolymers of (meth)acrylic acid, (meth)acrylic acid alkyl esters, and (meth)acrylic acid (polyoxyethylene monoalkyl ether).

The polyacrylamide compounds of component (E) include polyacrylamide and acrylamide copolymers, and examples of the acrylamide copolymers include copolymers containing acrylamide and/or acryloyldimethyltaurine as constituent units. Examples of the acrylamide copolymers include copolymers of acrylamide and acrylic acid (salt), copolymers of acrylic acid (salt) and acryloyldimethyltaurine (salt), and copolymers of hydroxyalkyl acrylate and acryloyldimethyltaurine (salt).

As the polyacrylamide compound of component (E), from the viewpoint of stability over time, a copolymer of acrylic acid (salt) and acryloyldimethyltaurine (salt) and a copolymer of hydroxyalkyl acrylate and acryloyldimethyltaurine (salt) are preferred, and a copolymer of acrylic acid (salt) and acryloyldimethyltaurine (salt) is more preferred.

Among the polyacrylamide compounds of component (E), commercially available polyacrylamides include, for example, SEPIGEL 305 (manufactured by SEPPIC), copolymers of acrylic acid (salt) and acryloyldimethyltaurine (salt) include (Na acrylate/Na acryloyldimethyltaurine) copolymers, commercially available products of which include, for example, SIMULGEL EG (manufactured by SEPPIC), copolymers of hydroxyalkyl acrylate and acryloyldimethyltaurine (salt) include (hydroxyethyl acrylate/Na acryloyldimethyltaurine) copolymers, commercially available products of which include, for example, SIMULGEL FL (manufactured by SEPPIC). These can be used alone or in combination as necessary.

Component (E), an ester copolymer of (meth)acrylic acid, (meth)acrylic acid alkyl ester, and (meth)acrylic acid (polyoxyethylene monoalkyl ether) (hereinafter abbreviated as "ester copolymer"), is a copolymer consisting of one or more monomers selected from an ester of (meth)acrylic acid and polyoxyethylene alkyl ether, and (meth)acrylic acid or a simple ester thereof.

The ester copolymer of component (E) is obtained by copolymerizing a monomer (a) selected from the group consisting of (meth)acrylic acid and (meth)acrylic acid alkyl esters, and a monomer (b) consisting of (meth)acrylic acid polyoxyalkylene alkyl ether. The bonding mode is not particularly limited and may be any of block bonding, random bonding, etc. In addition, it may contain other monomers and may have a crosslinked structure. When other monomers are contained, the other monomers are preferably less than 10 mol% (lower limit 0 mol%), more preferably 5 mol% or less (lower limit 0 mol%), and even more preferably 1 mol% or less (lower limit 0 mol%) with respect to the total monomers. Here, the contents of the structural units (a) and (b) correspond to the amounts of the monomers (a) and (b) added in the production stage.

The content ratio of the structural unit (a) and the structural unit (b) is not particularly limited, and for example, the molar ratio of the structural unit (a):structural unit (b) is 1:100 to 100:1.

In this specification, (meth)acrylic acid means acrylic acid and/or methacrylic acid.

In the alkyl (meth)acrylate ester, the alkyl group of the alkyl ester preferably has 1 to 22 carbon atoms, more preferably 1 to 18 carbon atoms, and even more preferably 1 to 8 carbon atoms. Examples of alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate.

The number of moles of polyoxyethylene added in the polyoxyethylene monoalkyl ether (meth)acrylate is preferably 10 to 30, more preferably 12 to 25, and even more preferably 20 to 25.

In the polyoxyethylene monoalkyl ether (meth)acrylate, the alkyl group of the alkyl ether preferably has 12 to 24 carbon atoms, and more preferably has 16 to 22 carbon atoms. Specific examples of polyoxyethylene monoalkyl ether (meth)acrylate include esters of acrylic acid and polyoxyethylene (20) stearyl ether, esters of methacrylic acid and polyoxyethylene (20) stearyl ether, esters of acrylic acid and polyoxyethylene (25) behenyl ether, and esters of methacrylic acid and polyoxyethylene (25) behenyl ether, with esters of methacrylic acid and polyoxyethylene (25) behenyl ether being even more preferred, and esters of methacrylic acid and polyoxyethylene (25) behenyl ether being even more preferred. The numbers in parentheses indicate the number of moles of ethylene oxide added.

Specific examples of the ester copolymer of component (E) include (meth)acrylic acid/(meth)acrylic acid alkyl ester/(meth)acrylic acid polyoxyethylene alkyl ether copolymers such as acrylates/polyoxyethylene methacrylate (20) cetyl ether copolymer, acrylates/polyoxyethylene methacrylate (20) stearyl ether copolymer, and acrylates/polyoxyethylene methacrylate (25) behenyl ether copolymer. The numbers in parentheses indicate the number of moles of ethylene oxide added.

Among these, from the viewpoints of stability over time and fresh, smooth spreadability upon application, the ester copolymer of component (E) is preferably an (acrylates/stearyl methacrylate) copolymer or an (acrylates/beheneth methacrylate) copolymer, more preferably an (acrylates/beheneth methacrylate) copolymer, and even more preferably an (acrylates/beheneth-25 methacrylate) copolymer. Examples of commercially available products include acrylates/polyoxyethylene (20) methacrylate stearyl ether copolymer (acrylates/steareth-20 methacrylate copolymer), trade name: Accurin (registered trademark) 22 (manufactured by Rohm and Haas Co.), and acrylates/polyoxyethylene (25) methacrylate behenyl ether copolymer (acrylates/beheneth-25 methacrylate copolymer), trade name: Accurin 28 (manufactured by Rohm and Haas Co.), trade name: NOVETHIX (registered trademark) L-10 (manufactured by Lubrizol Corporation).

The ester copolymer of component (E) can usually be neutralized with a basic substance before use. In this case, examples of the basic substance used include alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, and triisopropanolamine; inorganic bases such as sodium hydroxide, potassium hydroxide, and magnesium hydroxide; and basic amino acids such as L-arginine. These basic substances may be added in an amount sufficient to neutralize the ester copolymer of component (E), but the amount of the basic substance added is preferably, for example, 20 to 150% by mass relative to the ester copolymer of component (E).

In the present invention, the content of component (E) is preferably 0.01% or more as a lower limit, more preferably 0.05% or more, and even more preferably 0.1% or more, from the viewpoint of stability over time and fresh, smooth spread when applied. Also, from the viewpoint of fresh, smooth spread when applied, the content is preferably 1% or less as an upper limit, more preferably 0.8% or less, and even more preferably 0.5% or less. Also, the content of component (E) is preferably 0.01 to 1%, more preferably 0.05 to 0.8%, and even more preferably 0.1 to 0.5%. This range is more preferable because it provides excellent UV protection effect, water resistance, stability over time, and fresh, smooth spread when applied.

In the present invention, the content of the polyacrylamide compound of component (E) is preferably 0.05% or more as a lower limit, more preferably 0.1% or more, and even more preferably 0.2% or more, from the viewpoint of stability over time and fresh and smooth spread when applied. The content of the polyacrylamide compound of component (E) is preferably 0.05 to 1%, more preferably 0.1 to 0.8%, and even more preferably 0.2 to 0.5%, from the viewpoint of fresh and smooth spread when applied.

In the present invention, the content of the ester copolymer of component (E) is preferably 0.01% or more as a lower limit, more preferably 0.05% or more, and even more preferably 0.1% or more, from the viewpoint of stability over time and fresh and smooth spread when applied. Also, from the viewpoint of water resistance and fresh and smooth spread when applied, the upper limit is preferably 0.5% or less, more preferably 0.4% or less, and even more preferably 0.3% or less. Also, the content of the ester copolymer of component (E) is preferably 0.01 to 0.5%, more preferably 0.05 to 0.4%, and even more preferably 0.1 to 0.3%. By setting it in this range, it is more preferable because it is superior in UV protection effect, water resistance, stability over time, and fresh and smooth spread when applied.

In the present invention, although the effect can be obtained by appropriately containing the component (A) and the component (E), it is more preferable to specify the mass ratio of the component (A) and the component (E) since it is more excellent in stability over time and fresh and smooth spread when applied. The mass ratio (E)/(A) of the component (E) to the component (A) is preferably 0.1 or more as a lower limit, more preferably 0.3 or more, even more preferably 0.5 or more, and even more preferably 0.7 or more. The upper limit is preferably 8 or less, more preferably 5 or less, and even more preferably 4 or less. The mass ratio (E)/(A) is preferably 0.1 to 8, more preferably 0.3 to 5, even more preferably 0.5 to 4, and even more preferably 0.7 to 4. By setting it in this range, it is more preferable since it is more excellent in UV protection effect, water resistance, stability over time, and fresh and smooth spread when applied.

<Ingredient (F): Inulin fatty acid ester>

In the present invention, it is more preferable to further contain component (F) inulin fatty acid ester, since this makes it possible to improve water resistance and stability over time. The inulin fatty acid ester is an ester of inulin and a linear or branched saturated or unsaturated fatty acid having 8 to 32 carbon atoms, and the average molecular weight of the inulin is preferably in the range of 300 to 10,000, and inulin stearate is more preferable. Commercially available products include Leopearl ISK2 (manufactured by Chiba Flour Mills Co., Ltd.).

In terms of water resistance, the content of component (F) in the present invention is preferably 0.1% or more as a lower limit, more preferably 0.3% or more, and even more preferably 0.5% or more. In terms of fresh and smooth spreading when applied, the content is preferably 5% or less as an upper limit, more preferably 3% or less, and even more preferably 2% or less. In addition, the content of component (F) is preferably 0.1 to 5%, more preferably 0.3 to 3%, and even more preferably 0.5 to 2%. By setting it in this range, the effect of the present application, such as ultraviolet protection effect and fresh and smooth spreading when applied, is exhibited while providing superior stability over time and water resistance, which is more preferable.

<Component (G): Silica>
In the present invention, it is more preferable to further include component (G) silica, since this makes it possible to improve the fresh and smooth spreading and other properties when applied. As the silica, any silica that is used in ordinary cosmetics can be used regardless of its shape, such as spherical or amorphous, and regardless of the presence or absence of pores and the presence or absence of surface treatment. Examples include anhydrous silica, hydrated silica, silylated silica, and dimethylsilylated silica, and one or more of these can be used. Commercially available products include Silica 770 (average particle size 6.9 μm, amorphous, porous), 550 (average particle size 3.9 μm, amorphous, porous), 320 (average particle size 3.2 μm, amorphous, porous) (all manufactured by Fuji Silysia Chemical Ltd.), AEROSIL 200 (average particle size 12 nm, amorphous aerosol, non-porous), 300 (average particle size 7 nm, amorphous aerosol, non-porous), 380S (average particle size 6 nm, amorphous aerosol, non-porous), R972 (average particle size 16 nm, amorphous aerosol, non-porous), R974 (average particle size 12 nm, amorphous aerosol, non-porous), R976S (average particle size 7 nm, amorphous aerosol, non-porous) mist, nonporous), RX300 (average particle size 7 nm, amorphous mist, nonporous) (all manufactured by Nippon Aerosil Co., Ltd.), Sunsphere NP-30 (average particle size 4 μm, spherical, nonporous), NP-100 (average particle size 10 μm, spherical, nonporous), NP-200 (average particle size 20 μm, spherical, nonporous) (all manufactured by AGC Si-Tech Co., Ltd.), Godball D11-796C (average particle size 3.5 μm, spherical, porous), E2-824C (average particle size 1 μm, spherical, porous) (all manufactured by Suzuki Oil Industries Co., Ltd.), and the like.

The shape of component (G) in the present invention is not particularly limited, but from the viewpoint of fresh and smooth spreading during application, a spherical shape is preferable. The average particle size of component (G) is also not particularly limited, but the lower limit is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. The upper limit is preferably 50 μm or less, more preferably 25 μm or less, and even more preferably 15 μm or less.

In the present invention, the content of component (G) is preferably 0.3% or more as a lower limit, more preferably 0.5% or more, and even more preferably 0.8% or more, from the viewpoint of fresh and smooth spreading when applied. Also, from the viewpoint of stability over time, the upper limit is preferably 5% or less, more preferably 3% or less, and even more preferably 2% or less. Also, the content of component (G) is preferably 0.3 to 5%, more preferably 0.5 to 3%, and even more preferably 0.8 to 2%. By setting it in this range, it is more preferable because it is superior in fresh and smooth spreading when applied while exhibiting the effects of the present application, such as ultraviolet protection effect, stability over time, and water resistance.

Furthermore, in the present invention, from the viewpoint of stability over time and smoothness of spread during application, it is preferable that the composition is substantially free of linear saturated alcohols. The linear saturated alcohol may be any linear saturated higher alcohol that is generally used in cosmetics, such as cetyl alcohol, cetostearyl alcohol, stearyl alcohol, and behenyl alcohol. Here, in the present invention, substantially free of linear saturated alcohol means that the oil-in-water emulsion composition contains less than 0.5%, preferably 0.3% or less, more preferably 0.2% or less, even more preferably 0.1% or less, and even more preferably 0% (no alcohol).

In addition to the above-mentioned components, the oil-in-water emulsion composition of the present invention may contain, within the scope that does not impair the effects of the present invention, components normally used in cosmetics, quasi-drugs, pharmaceuticals, etc., water, surfactants other than component (D), oils other than component (B), gelling agents other than component (F), powders other than components (A), (C) and (G), alcohols, water-soluble polymers other than component (E), film-forming agents, resins, moisturizers, antibacterial agents, fragrances, deodorants, salts, chelating agents, UV absorbers other than component (B), pH adjusters, cooling agents, plant extracts, vitamins, amino acids and other cosmetic ingredients.

The oil-in-water emulsion composition of the present invention may contain water, but is not particularly limited as long as it can be contained in cosmetics, quasi-drugs, pharmaceuticals, etc. The water may be purified water, hot spring water, deep sea water, or steam-distilled water from plants, and one or more types may be appropriately selected and used as necessary. The content is not particularly limited and may be appropriately contained depending on the amount of other ingredients, but may be approximately 40 to 85% in the oil-in-water emulsion composition.

The oil-in-water emulsion composition of the present invention can be in various forms, such as liquid, gel, milk, cream, semi-solid, solid, and mousse, among which a cream form is preferred for achieving the effects of the present invention. Here, a cream form is one having a viscosity of 50,000 mPa·s or less, preferably 40,000 mPa·s or less, more preferably 35,000 mPa·s or less, and even more preferably 30,000 mPa·s or less, as measured at 25°C using a Brookfield rotational viscometer. The lower limit is 5,000 mPa·s or more, preferably 10,000 mPa·s or more, more preferably 15,000 mPa·s or more, and even more preferably 20,000 mPa·s or more.

The oil-in-water emulsion composition of the present invention may be used as a final formulation as it is, or may be mixed with other ingredients to form a final formulation. Examples of the final formulation include cosmetics, specifically skin care cosmetics such as lotions, creams, beauty essences, lip balms, and sunscreens, makeup cosmetics such as foundations, makeup bases, blushers, eye shadows, lipsticks, and lip glosses, and cosmetics for the scalp or hair such as hair rinses, hair creams, and hair styling products. In the present invention, from the viewpoint of being able to realize the effects of the present invention more effectively, it is preferable that the cosmetic is used for sunscreen purposes. Here, as sunscreen purposes, sunscreens (lotions, creams, lotions, beauty essences, etc.), bases, foundations, and the like that exhibit ultraviolet protection effects can be applied. In addition, the method of use includes a method of using it on hands, fingers, or cotton, a method of using it by impregnating nonwoven fabrics, and a method of using it as a spray or aerosol.

The content of the oil-in-water emulsion composition of the present invention contained in the cosmetic is not particularly limited, but is preferably 20 to 100%, and more preferably 30 to 90%.

(Production method)
The oil-in-water emulsion composition of the present invention can be produced by a method generally known in the art, and any production equipment may be used as long as it is a dispersion/emulsification equipment such as a general dispersion equipment. For example, the composition can be obtained by uniformly mixing components (A), (D), and (E) in a dispersion, adding and mixing components (B), (C), and (F) that have been dissolved and dispersed by heating thereto, cooling the mixture, and adding and mixing component (G).

The present invention can also employ the following configuration.
<1>
The following components (A) to (E):
(A) Cellulose nanofibers (B) Liquid oil containing an oil-soluble UV absorber (C) Hydrophobically treated metal oxide particles (D) Nonionic surfactant 0.2 to 2.5% by mass
(E) An oil-in-water emulsion composition containing a polyacrylamide compound and one or more salt-tolerant water-soluble polymers selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid alkyl esters, and (meth)acrylic acid (polyoxyethylene monoalkyl ether) ester copolymers.
<2>
The oil-in-water emulsion composition according to item 1, wherein the content of the component (A) is 0.05 to 1 mass %.
<3>
The oil-in-water emulsion composition according to item <1> or <2>, wherein the component (D) contains at least a polyglycerol fatty acid ester, and the content of the polyglycerol fatty acid ester in the component (D) is 50 mass% or more.
<4>
The oil-in-water emulsion composition according to any one of <1> to <3>, wherein a content mass ratio (E)/(A) of the component (E) to the component (A) is 0.1 to 8.
<5>
The oil-in-water emulsion composition according to any one of <1> to <4>, which is substantially free of a linear saturated alcohol.
<6>
The oil-in-water emulsion composition according to any one of <1> to <5>, wherein the component (D) contains at least two kinds of nonionic surfactants having different HLBs, and the weighted average HLB value of the nonionic surfactants is 10 to 15.
<7>
The oil-in-water emulsion composition according to any one of <1> to <6>, further comprising a component (F) an inulin fatty acid ester.
<8>
The oil-in-water emulsion composition according to any one of <1> to <7>, further comprising a component (G) silica.
<9>
The oil-in-water emulsion composition according to any one of <1> to <8>, wherein the oil-in-water emulsion composition is a cosmetic used for sunscreen purposes.

The effects of the present invention will be explained using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Furthermore, unless otherwise specified, each operation is performed at room temperature (25°C). In the examples, the indications "parts" or "%" may be used, but unless otherwise specified, they represent "parts by mass" or "% by mass".

Examples 1 to 22 and Comparative Examples 1 to 7: Sunscreen (oil-in-water type)
Sunscreens (oil-in-water type) having the compositions shown in Tables 1 and 2 below were prepared by the manufacturing method described below, and (a) UV protection effect, (b) water resistance, (c) stability over time (50°C/1M), and (d) fresh and smooth spreadability upon application were evaluated using the evaluation methods and criteria described below, and the results are shown in Tables 1 and 2.

(Note 1) LeoCrysta C-2EP (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
(Note 2) Cellenpia CS-01C (manufactured by Nippon Paper Industries Co., Ltd.)
(Note 3) CMC Daicel 1390 (manufactured by Daicel Miraize Co., Ltd.)
(Note 4) UVINUL MC80 (manufactured by BASF)
(Note 5) Ubinal A PLUS GRANULAR (manufactured by BASF)
(Note 6) TINOSORB S (manufactured by BASF)
(Note 7) PARSOL SLX (manufactured by DSM)
(Note 8) Zinc oxide used was MZ-500 (manufactured by Teika Co., Ltd.), and the amount of OTS/dimethicone treated was 15% based on the mass of zinc oxide.
(Note 9) MZX-304OTS (manufactured by Teika Co., Ltd.) (average particle size: 35 nm)
(Note 10) MZ-500 (average particle size: 25 nm) (manufactured by Teika Co., Ltd.)
(Note 11) Nikkor HCO-80 (manufactured by Nikko Chemicals)
(Note 12) Nikkor HCO-10 (manufactured by Nikko Chemicals Co., Ltd.)
(Note 13) NIKKOL Decaglyn 1-SV (manufactured by Nikko Chemicals Co., Ltd.)
(Note 14) Leodor AO-15V (Kao Corporation)
(Note 15) SIMULGEL EG (manufactured by SEPPIC)
(Note 16) NOVETHIX (registered trademark) L-10 (manufactured by Lubrizol Corporation)
(Note 17) Avalure (registered trademark) Flex-6 CC Polymer (manufactured by Lubrizol Corporation)
(Note 18) Leopard ISK2 (manufactured by Chiba Flour Mills)
(Note 19) God Ball D11-796C (manufactured by Suzuki Oil Industries Co., Ltd.)

(Production method)
A: Mix 20% of ingredients 9 to 12 and ingredients 13 to 15 and disperse using a three-roll mill.
B: Mix ingredients 4 to 8, 24, and 26 with the remaining ingredients 9 to 12 and dissolve uniformly at 70°C.
C: Components 1 to 3, components 17 to 23, and a portion of component 27 are uniformly dispersed at 70°C.
D: Add A to B and disperse evenly.
E: Add D to C and disperse evenly.
F: E was cooled to room temperature, and the remaining component 27, component 16 and component 25 were added to obtain a sunscreen (oil-in-water type).

(Evaluation Method 1: (a) UV Protection Effect)
Each sample was applied to a PMMA plate (HELIOPLATE HD6, manufactured by Labsphere) by spreading it with a finger so as to give a coating of 2 mg/ ^cm2 , and the sample was left to stand for 20 minutes. The SPF of the sample was then measured using an SPF analyzer (UV-2000S, manufactured by Labsphere). Ten points on the PMMA plate were measured, and the UV protection effect was judged from the average value obtained according to the following three-level judgment criteria.
<Three-level evaluation criteria>
[Average score]: [Judgment]
25 or more: ◎ (Excellent)
10 or more but less than 25: 〇 (good)
Less than 10: × (not acceptable)

(Evaluation Method 2: (b) Water Resistance)
Each sample was applied to a PMMA plate (HELIOPLATE HD6, manufactured by Labsphere) by spreading it with fingers to 2 mg/cm ² , and then the sample was left to stand for 20 minutes. SPF measurement was performed using an SPF analyzer (UV-2000S, manufactured by Labsphere) to measure the SPF value before water bath. Thereafter, the sample was immersed in a water bath at 25°C with the coated surface facing up together with the substrate on which the sample was applied, and the water was stirred lightly for 15 minutes while maintaining the water temperature. The substrate was then slowly removed and left to dry for 30 minutes or more. This operation was repeated twice, and the SPF value after water bath was measured again using the SPF analyzer. Based on the ratio of the SPF values obtained before and after water bath (SPF measurement value after water bath)/(SPF measurement value before water bath), the water resistance was judged according to the following three-stage judgment criteria.
<Three-level evaluation criteria>
[Ratio (SPF measurement value after bathing)/(SPF measurement value before bathing)]: [Evaluation]
0.8 or above: ◎ (Excellent)
0.6 or more and less than 0.8: Good
Less than 0.6: × (not acceptable)

(Evaluation method 3: (c) Stability over time (50°C/1M))
30 g of each sample was placed in a No. 6 standard glass bottle (Kawaguchi Pharmaceutical Co., Ltd.) and stored in a thermostatic chamber at 50° C. for one month (1M), and the state after one month was observed. Based on the results, the stability over time was evaluated according to the following three-stage evaluation criteria.
<Three-level evaluation criteria>
[Evaluation]: [Judgment]
Almost no change in appearance: ◎ (Excellent)
No separation observed, but: 〇 (Acceptable)
Either deterioration of texture or the appearance of lumps is observed. Separation is observed, texture is very poor, and lumps are visible: × (Not acceptable)

(Evaluation method 4: (d) Fresh and smooth spread upon application)
100 mg of each sample was spread over an area of 3 x 4 cm of artificial leather with a finger for 60 seconds, and the average coefficient of friction was measured using a friction tester (KES-SE). The measurement conditions were a moving speed of 0.5 mm/sec, a measuring distance of 20 mm, and a load of 25 g. Samples with a lower average coefficient of friction can be spread without feeling resistance, and therefore can be spread smoothly. The average coefficient of friction (MIU) of each sample was judged according to the following criteria, and the fresh and smooth spreadability at the time of application was judged according to the following three-level judgment criteria.
<Three-level evaluation criteria>
[Average friction coefficient]: [Judgment]
Less than 4.0: ◎ (Excellent)
4.0 or more, less than 4.5: 〇 (good)
4.5 or above: × (not acceptable)

As is clear from the results in Tables 1 and 2, the sunscreens (oil-in-water type) of Examples 1 to 22 had higher UV protection effect and water resistance than Comparative Examples 1 to 7, and also had excellent stability over time, and also had excellent fresh and smooth spreadability upon application. In addition, the results of Example 22, which contained behenyl alcohol, suggested that it is preferable to be substantially free of linear saturated alcohol.

On the other hand, in Comparative Example 1 which did not contain the component (A), the stability over time could not be guaranteed, and a satisfactory product was not obtained.
In Comparative Example 2, in which a water-soluble polymeric cellulose gum that is not nanofiber was used instead of component (A), the stability over time could not be guaranteed, and a satisfactory product was not obtained.
In Comparative Example 3, in which untreated fine particle zinc oxide was used instead of component (C), satisfactory results were not obtained in terms of water resistance and fresh, smooth spreadability upon application.
In Comparative Example 4, in which the content of component (D) was less than 0.2%, the stability over time could not be ensured, and a satisfactory product was not obtained.
In Comparative Example 5, in which the content of component (D) exceeded 2.5%, satisfactory results were not obtained in terms of water resistance and fresh, smooth spreadability upon application.
In Comparative Example 6, which did not contain the component (E), the stability over time could not be ensured, and a satisfactory product was not obtained.
In Comparative Example 7, in which a salt-resistant water-soluble polymer (PEG-240/decyltetradeceth-20/HDI) copolymer was used instead of component (E), satisfactory results were not obtained in terms of stability over time and fresh, smooth spreadability upon application.

Example 23: Sunscreen gel (oil-in-water type)
(Components) (% by mass)
1. Crystalline cellulose Component (A) Note 1 0.2
2. Ethylhexyl methoxycinnamate Component (B) Note 4 7
3. Diethylamino hydroxybenzoyl benzoic acid hexyl ester
Component (B) Note 5 2
4. 2,4-Bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine
Component (B) Note 6 2
5. Polysilicone-15 Component (B) Note 7 1
6. Isotridecyl isononanoate Component (B) 2
7. Isododecane Component (B) 3
8. Cetyl 2-ethylhexanoate Component (B) 5
9. Polyhydroxystearic acid Component (B) 0.25
10. Triethoxyoctylsilane-treated zinc oxide Component (C) Note 9 10
11. PEG-10 hydrogenated castor oil (HLB: 6.5) Component (D) Note 12
0.05
12. Polyglyceryl-10 stearate (HLB: 12.0)
Component (D) Note 13 0.5
13. (Sodium acrylate/sodium acryloyldimethyltaurate) copolymer
Component (E) Note 15 0.4
14. Inulin stearate Component (F) Note 18 1
15. Polymethylsilsesquioxane 2
16. Silica Component (G) Note 19 1
17. Olive oil Component (B) 0.1
18. Diethylhexyl succinate Component (B) Note 20 1
19. Purified water remaining 20. Ethanol 10
21. Hyaluronic acid 0.15
22. Trehalose 0.05
23. Artemisia capillaris extract 0.01
(Note 20) CRODAMOL OSU (manufactured by Croda Corporation)

(Production method)
A: Mix 20% of ingredients 6 to 8 with ingredients 9 and 10 and disperse using a three-roll mill.
B: Mix ingredients 2 to 5, 11, 12, 14, 17, and 18 with the remainder of ingredients 6 to 8 and dissolve uniformly at 70°C.
C: Components 1, 13, 20 to 23 and a portion of component 19 are uniformly dispersed at 70°C.
D: Add A to B and disperse evenly.
E: Add D to C and disperse evenly.
F: E was cooled to room temperature, and the remaining component 19 and components 15 and 16 were added to obtain a sunscreen gel (oil-in-water type).

The sunscreen gel (oil-in-water type) of Example 23 had high UV protection effect and water resistance, excellent stability over time, and also had excellent moisturizing and smooth spreadability upon application.

Example 24: Foundation (oil-in-water type)
(Components) (% by mass)
1. Crystalline cellulose Component (A) Note 1 0.2
2. Ethylhexyl methoxycinnamate Component (B) Note 4 7
3. Diethylamino hydroxybenzoyl benzoic acid hexyl ester
Component (B) Note 5 2
4. 2,4-Bis{[4-(2-ethylhexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine
Component (B) Note 6 2
5. Polysilicone-15 Component (B) Note 7 1
6. Isotridecyl isononanoate Component (B) 2
7. Isododecane Component (B) 3
8. Cetyl 2-ethylhexanoate Component (B) 5
9. Polyhydroxystearic acid Component (B) 0.25
10. Triethoxyoctylsilane-treated zinc oxide Component (C) Note 9 10
11. PEG-10 hydrogenated castor oil (HLB: 6.5)
Component (D) Note 12 0.15
12. Polyglyceryl-10 stearate (HLB: 12.0)
Component (D) Note 13 0.5
13. (Sodium acrylate/sodium acryloyldimethyltaurate) copolymer
Component (E) Note 15 0.5
14. Sorbitan sesquioleate (HLB: 3.7)
Component (D) Note 12 0.05
15. Silica-treated red iron oxide Note 21 2
16. Silica-treated yellow iron oxide Note 22 2
17. Silica-treated black iron oxide Note 23 1
18. Silica-treated sericite 2
19. Silica-treated titanium dioxide Note 24 3
20. Inulin stearate Component (F) Note 18 1
21. Talc 2
22. Silica Component (G) Note 19 1
23. Olive oil Component (B) 0.1
24. Diethylhexyl succinate Component (B) Note 20 1
25. Purified water Remaining amount 26. 1,3-butylene glycol 2
27. Ethanol 10
28. Hyaluronic acid 0.15
29. Trehalose 0.05
30. Artemisia capillaris extract 0.01
(Note 21) Sympholite RW-TE (manufactured by Nikki Catalysts and Chemicals, 10% silica)
(Note 22) Sympholite YW-TE (manufactured by Nikki Catalysts and Chemicals, 10% silica)
(Note 23) Sympholite BW-TE (manufactured by Nikki Catalysts and Chemicals, 10% silica)
(Note 24) Silica treatment of TiO ₂ MP-1133 (manufactured by Teika Co., Ltd.) (surface treatment 3.0%)

(Production method)
A: Mix 20% of ingredients 6 to 8 with ingredients 9 and 10 and disperse using a three-roll mill.
B: Mix ingredients 2 to 5, a portion of 11, 12, 20, 23, and 24 with the remainder of ingredients 6 to 8 and dissolve homogeneously at 70°C.
C: Mix the remaining component 11, components 14 to 19, and 26, and disperse using a three-roll mill.
D: Components 1, 13, 27 to 30 and a portion of component 25 are uniformly dispersed at 70°C.
E: Add A to B and disperse evenly.
F: Add C to D, then add E and emulsify.
G: F was cooled to room temperature, and the remaining ingredient 25 and ingredients 21 and 22 were added to obtain a foundation (oil-in-water type).

The foundation of Example 24 (oil-in-water type) had high UV protection and water resistance, excellent stability over time, and also had excellent moisturizing and smooth spreadability upon application.

Claims (9)

The following components (A) to (E):
(A) Cellulose nanofibers (B) Liquid oil containing an oil-soluble UV absorber (C) Hydrophobically treated metal oxide particles (D) Nonionic surfactant 0.2 to 2.5% by mass
(E) An oil-in-water emulsion composition containing a polyacrylamide compound and one or more salt-tolerant water-soluble polymers selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid alkyl esters, and (meth)acrylic acid (polyoxyethylene monoalkyl ether) ester copolymers. The oil-in-water emulsion composition according to claim 1, wherein the content of component (A) is 0.05 to 1% by mass. The oil-in-water emulsion composition according to claim 1 or 2, wherein the component (D) contains at least a polyglycerol fatty acid ester, and the content of the polyglycerol fatty acid ester in the component (D) is 50% by mass or more. The oil-in-water emulsion composition according to claim 1 or 2, wherein the mass ratio (E)/(A) of the component (E) to the component (A) is 0.1 to 8. The oil-in-water emulsion composition according to claim 1 or 2, which is substantially free of linear saturated alcohols. The oil-in-water emulsion composition according to claim 1 or 2, wherein component (D) contains at least two types of nonionic surfactants with different HLBs, and the weighted average HLB value of the nonionic surfactants is 10 to 15. The oil-in-water emulsion composition according to claim 1 or 2, further comprising component (F) an inulin fatty acid ester. The oil-in-water emulsion composition according to claim 1 or 2, further comprising component (G) silica. The oil-in-water emulsion composition according to claim 1 or 2, wherein the oil-in-water emulsion composition is a cosmetic used for sunscreen purposes.