Oil-in-water emulsion cosmetic

Abstract

Provided is an oil-in-water emulsion cosmetic which contains pigment-grade hydrophobized particles and is excellent in terms of emulsion stability and tone-up property.　This oil-in-water emulsion cosmetic comprises a dispersion medium including water and oil droplets dispersed in the dispersion medium, wherein the dispersion medium contains pigment-grade hydrophobized particles and the oil droplets have an average droplet diameter of 1 μm or smaller.

Description

Oil-in-water emulsion cosmetics

[0001] The present disclosure relates to an oil-in-water emulsion cosmetic.

[0002] In the field of cosmetics, various oil-in-water emulsion cosmetics have been developed.

[0003] Patent Document 1 discloses an O / W emulsion composition containing the following components (a) to (c), wherein the average particle size of the oil phase containing component (a) is 700 nm or less: (a) an organic UV absorber that is oily at 20°C and contains the following (a1): (a1) octocrylene (b) an organic UV absorber that is solid at 20°C and is selected from the following (b1) and (b2): (b1) bisethylhexyloxyphenol methoxyphenyl triazine (b2) methylene bisbenzotriazolyl tetramethylbutylphenol (c) a polyoxyethylene-polyoxyalkylene alkyl ether block polymer represented by the following general formula (1) or (2): R １ O-(PO)m-(EO)n-H...(1) [wherein, R １ is a hydrocarbon group having 16 to 18 carbon atoms, PO is an oxypropylene group, and EO is an oxyethylene group. PO and EO are added in blocks. m and n respectively represent the average number of moles of PO and EO added, with 70>m>4, 70>n>10, and n>m.] R ２ O-(AO)p-(EO)q-R ３ ...(2) [wherein, R ２ , R ３ may be the same or different, and each represents a hydrocarbon group having 1 to 4 carbon atoms, AO represents an oxyalkylene group having 3 to 4 carbon atoms, and EO represents an oxyethylene group. AO and EO are added in a block form. p and q represent the average number of moles of AO and EO added, respectively, and are 1≦p≦70, 1≦q≦70, and 0.2<(q / (p+q))<0.8.

[0004] Patent Document 2 discloses an oil-in-water emulsion type composition containing, in a physiologically acceptable aqueous medium, i) at least one polymer containing a sulfonic acid group, ii) a polysaccharide modified with a hydrophobic chain, and iii) at least one (meth)acrylic acid polymer and / or one silicone surfactant selected from oxyethylenated polydimethylsiloxanes, and a pigment and / or a filler.

[0005] JP 2010-132647 A JP 2016-529275 A

[0006] When hydrophobically treated particles are blended into an oil-in-water emulsion cosmetic, for example, the particles are generally blended into the oil phase (oil droplets). As described in Patent Document 2 (

[0010] ), it is known in the art that the use of powders (e.g., pigments, fillers) destabilizes the emulsification performance of oil-in-water emulsion cosmetics.

[0007] Furthermore, for example, in order to achieve a tone-up effect that brightens the skin color, relatively large pigment-grade hydrophobic treated particles may be used as hydrophobic treated particles to be blended into oil-in-water emulsion cosmetics.

[0008] When an oil-in-water emulsion cosmetic containing such hydrophobically treated particles in the oil phase (oil droplets) is applied to the skin, the oil droplets containing the hydrophobically treated particles tend to adsorb and remain near the skin's ridges or sulci, which have high surface activity, with the oil attracted by the particles. As a result, oil containing hydrophobically treated particles (e.g., pigment-grade hydrophobically treated particles) is difficult to apply evenly to the skin, which can result in uneven toning.

[0009] Therefore, a subject of the present disclosure is to provide an oil-in-water emulsion cosmetic that contains pigment-grade hydrophobized particles and has excellent emulsion stability and tone-up properties.

[0010] Aspect 1: An oil-in-water emulsion cosmetic comprising a dispersion medium containing water, and oil droplets dispersed in the dispersion medium, wherein the dispersion medium contains pigment-grade hydrophobized particles, and the oil droplets have an average particle size of 1 μm or less. Aspect 2: The cosmetic according to Aspect 1, wherein the oil droplets contain a polyoxyethylene-polyoxyalkylene alkyl ether block polymer as a nonionic surfactant. Aspect 3: The cosmetic according to Aspect 2, wherein the block polymer is at least one selected from the group consisting of the following formulas 1 and 2: R １ O-(PO) ｍ - (EO) ｎ -H...Formula 1 In Formula 1, R １ is a hydrocarbon group having 16 to 18 carbon atoms, PO is an oxypropylene group, EO is an oxyethylene group, PO and EO are added in block form, m and n mean the average number of moles of PO and EO added, respectively, and satisfy the relationships 70>m>4, 70>n>10, and n>m. R ２ O-(AO) p - (EO) ｑ -R ３ …Formula 2 In Formula 2, R ２ and R ３may be the same or different and each is a hydrocarbon group having 1 to 4 carbon atoms, AO is an oxyalkylene group having 3 to 4 carbon atoms, EO is an oxyethylene group, AO and EO are added in a block form, and p and q respectively represent the average number of moles of AO and EO added, and satisfy the relationships 1≦p≦70, 1≦q≦70, and 0.2<(q / (p+q))<0.8. Aspect 4 The cosmetic according to any one of Aspects 1 to 3, wherein the dispersion medium contains a polyether-modified silicone having an HLB of 10.0 or more and 18.0 or less. Aspect 5 The cosmetic according to Aspect 4, wherein the mass ratio of the pigment-grade hydrophobized particles to the polyether-modified silicone is 5.0 or more. Aspect 6 The cosmetic according to any one of Aspects 1 to 5, further comprising an ultraviolet absorber. Aspect 7: The cosmetic according to any one of Aspects 1 to 6, wherein the pigment-grade hydrophobized particles have an average particle size of 250 nm or more. Aspect 8: The cosmetic according to any one of Aspects 1 to 7, wherein the viscosity is 10,000 mPa·s or less.

[0011] According to the present disclosure, it is possible to provide an oil-in-water emulsion cosmetic that contains pigment-grade hydrophobized particles and has excellent emulsion stability and tone-up properties.

[0012] (a) is a schematic diagram showing oil droplets (emulsion particles) colliding with each other and coalescing during a rolling stability test, and (b) is a schematic diagram showing the state of pigment-grade hydrophobized particles adhering to the surface of coarse oil droplets after the rolling stability test. (a) is a schematic diagram showing the state of oil droplets (emulsion particles) and pigment-grade hydrophobized particles during the rolling stability test, and (b) is a schematic diagram showing the state of oil droplets and pigment-grade hydrophobized particles after the rolling stability test. (a) is a schematic diagram of an oil-in-water emulsion cosmetic according to one embodiment of the present disclosure, (b) is a schematic diagram of the cosmetic applied to the skin and the moisture has dried, and (c) is a schematic diagram of the cosmetic blended into the skin. (a) is a schematic diagram of an oil-in-water emulsion cosmetic containing oil droplets containing pigment-grade hydrophobized particles, and (b) is a schematic diagram of the cosmetic blended into the skin.

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present invention.

[0014] The oil-in-water emulsion cosmetic of the present disclosure comprises a dispersion medium containing water and oil droplets dispersed in the dispersion medium, the dispersion medium containing pigment-grade hydrophobized particles, and the average particle size of the oil droplets is 1 μm or less.

[0015] Without being limited by the theory, the mechanism by which the cosmetic composition of the present disclosure exhibits excellent emulsion stability and tone-up properties despite containing pigment-grade hydrophobized particles is believed to be as follows.

[0016] As mentioned above, it is well known that the use of powders (e.g., pigments, fillers) generally destabilizes the emulsification performance of oil-in-water emulsion cosmetics. However, the present inventors have discovered that when the average particle size of the oil droplets (emulsion particles) in the cosmetic is 1 μm or less, the emulsion stability of the oil-in-water emulsion cosmetic is improved, even if pigment-grade hydrophobized particles are contained in the dispersion medium.

[0017] If the size of the oil droplets (emulsion particles) in an oil-in-water emulsion cosmetic is large, it is thought that when a rolling stability test is conducted, for example, the oil droplets 12 are likely to collide with each other and coalesce, as shown in Figure 1. As a result, pigment-grade hydrophobic treated particles 10 adhere to the surfaces of the enlarged oil droplets 12, disrupting the emulsion balance and reducing the emulsion stability of the oil droplets. The adhesion of pigment-grade hydrophobic treated particles to the surfaces of the enlarged oil droplets has been observed using an optical microscope.

[0018] On the other hand, when the size of the oil droplets in an oil-in-water emulsion cosmetic is small, it is thought that, for example, even when a rolling stability test is carried out, coalescence due to collisions between oil droplets 22 is less likely to occur than in the case of large oil droplets, as shown in Figure 2. As a result, it is thought that the pigment-grade hydrophobic treated particles 20 are less likely to adhere to the surfaces of the oil droplets 22 than in the case of large oil droplets, and therefore the emulsion stability of the oil droplets is improved.

[0019] Furthermore, as described above, when obtaining an oil-in-water emulsion cosmetic containing hydrophobically treated particles, the hydrophobically treated particles are generally blended into the oil phase because they are hydrophobic. However, the present inventors have discovered that blending pigment-grade hydrophobically treated particles into the aqueous phase of an oil-in-water emulsion cosmetic improves the tone-up effect when the cosmetic is applied to the skin.

[0020] In conventional oil-in-water emulsion cosmetics containing pigment-grade hydrophobized particles in the oil phase, it is believed that the pigment-grade hydrophobized particles 40 are present in a densely packed state in the oil phase, as shown in Figure 4(a).

[0021] When an oil-in-water emulsion cosmetic containing such pigment-grade hydrophobized particles in the oil phase is applied to the skin, it is believed that the pigment-grade hydrophobized particles 40 and oil 42 are densely packed together and tend to be adsorbed relatively unevenly near the skin's ridges or sulci, which are lipophilic and have high surface activity, as shown in Figure 4(b).

[0022] On the other hand, in the oil-in-water emulsion cosmetic of the present disclosure, which contains pigment-grade hydrophobized particles in the aqueous phase, when such a cosmetic is applied to the skin, it is believed that the pigment-grade hydrophobized particles 30 are more likely to be uniformly adsorbed and remain on the skin than in an oil-in-water emulsion cosmetic which contains pigment-grade hydrophobized particles in the oil phase, as shown in Figure 3(b). As a result, the pigment-grade hydrophobized particles that contribute to the tone-up effect are uniformly distributed on the skin, which is believed to result in an improved tone-up effect compared to an oil-in-water emulsion cosmetic which contains pigment-grade hydrophobized particles in the oil phase.

[0023] Furthermore, when the average particle size of the oil droplets (emulsified particles) in the cosmetic is 1 μm or less, it is believed that the pigment-grade hydrophobic treated particles adhere to the skin with closer spacing between particles as shown in Figure 3(b) compared to when using a cosmetic containing oil droplets with an average particle size of 10 μm. As a result, it is believed that the tone-up effect is improved. Note that an improved tone-up effect means that the pigment-grade hydrophobic treated particles are uniformly adhered to the skin, and therefore it is believed that the UV protection effect (SPF) is also improved.

[0024] <Oil-in-Water Emulsion Cosmetic> <Dispersion Medium> The dispersion medium (aqueous phase) in the oil-in-water emulsion cosmetic of the present disclosure contains water and pigment-grade hydrophobized particles.

[0025] (Water) The amount of water to be blended is not particularly limited, and, for example, from the viewpoint of emulsion stability and the like, the amount of water may be 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more, relative to the total amount of the cosmetic, and may be 90% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass or less.

[0026] There are no particular limitations on the water that can be used in the oil-in-water emulsion cosmetic of the present disclosure, and for example, water used in cosmetics and quasi-drugs can be used, such as ion-exchanged water, distilled water, ultrapure water, and tap water.

[0027] (Pigment-grade hydrophobized particles) The amount of pigment-grade hydrophobized particles to be blended is not particularly limited and can be appropriately selected based on the desired effect (e.g., tone-up effect, SPF) depending on the application. The amount of pigment-grade hydrophobized particles to be blended can be, for example, 0.5% by mass or more, 1.0% by mass or more, or 1.5% by mass or more relative to the total amount of the cosmetic, and can be 15% by mass or less, 12% by mass or less, 10% by mass or less, 8.0% by mass or less, 6.0% by mass or less, or 5.0% by mass or less.

[0028] The average particle size of the pigment-grade hydrophobic treated particles can be appropriately selected so as to obtain the desired effect (e.g., tone-up effect, SPF) depending on the application. The average particle size of the pigment-grade hydrophobic treated particles can be, for example, 250 nm or more, 300 nm or more, 350 nm or more, or 400 nm or more. Pigment-grade hydrophobic treated particles with an average particle size of 300 nm or more can preferably exhibit a tone-up effect that brightens skin color. The upper limit of the average particle size is not particularly limited, and can be, for example, 100 μm or less, 70 μm or less, 50 μm or less, 30 μm or less, 10 μm or less, 5 μm or less, 1 μm (1,000 nm) or less, 800 nm or less, 700 nm or less, or 600 nm or less. Here, the average particle size of the pigment-grade hydrophobic treated particles in the present disclosure may be the size of primary particles or aggregated secondary particles, and can be calculated by static light scattering.

[0029] The hydrophobic treatment for pigment-grade hydrophobized particles is not particularly limited, and may be any treatment that modifies the surface of such particles with an organic compound to hydrophobize them, such as silicone-based or silane-based treatments using methylhydrogenpolysiloxane, dimethylpolysiloxane (dimethicone), alkylsilane, etc.; fluorine-based treatments using perfluoroalkyl phosphate esters, perfluoroalcohols, etc.; titanate-based treatments using alkyl titanates, etc.; amino acid treatments using N-acylglutamic acid, etc.; and other treatments such as lecithin treatment, metal soap treatment, fatty acid treatment, and alkyl phosphate ester treatment. The hydrophobization treatments may be used alone or in combination. The hydrophobization treatment may also be carried out using a hydrophobization treatment agent.

[0030] Examples of silicones that can be used as hydrophobic treatment agents include known silicones having a hydrogen-silicon bond, such as methylhydrogenpolysiloxane (dimethicone / methicone) copolymer. Other examples include triethoxysilylethylpolydimethylsiloxyethyldimethicone and triethoxysilylethylpolydimethylsiloxyethylhexyldimethicone, which have an alkoxy group-silicon bond as a reactive group. Other examples include dimethylpolysiloxane and tetrahydrotetramethylcyclotetrasiloxane.

[0031] Examples of the silane-based treatment agent include a silylating agent having an organic group introduced therein and a silane coupling agent, such as triethoxycaprylylsilane.

[0032] Examples of titanate-based treatment agents include titanium coupling agents such as alkyl titanates, pyrophosphate-type titanates, phosphorous-type titanates, and amino acid-type titanates.

[0033] The type of particles constituting the pigment-grade hydrophobic treated particles is not particularly limited and can be appropriately selected to obtain the desired effect (e.g., tone-up effect, SPF) depending on the application. Examples of pigment-grade hydrophobic treated particles include inorganic particles, specifically inorganic oxide particles, such as titanium oxide particles, zinc oxide particles, and cerium oxide particles (sometimes referred to as "inorganic white pigments"). In addition, inorganic particles generally classified as pearlescent agents (luminescent pigments), colorants, or phosphors can also be used as the pigment-grade hydrophobic treated particles of the present disclosure. Organic particles can also be used as the pigment-grade hydrophobic treated particles of the present disclosure. The pigment-grade hydrophobic treated particles can be used alone or in combination of two or more types.

[0034] In the present disclosure, the term "pearl-forming agent" does not include coloring materials or phosphors, and refers to particles that exhibit brilliance. Pearling agents typically have a flat, flaky or scale-like form. In addition, in the present disclosure, the term "coloring agent" refers to a material that exhibits a color other than white, does not include pearling agents or phosphors, and does not exhibit brilliance, which can cause cosmetics to develop color. For example, from the perspective of achieving a tone-up effect, when a pearling agent is used, it is preferable to use it in combination with inorganic oxide particles such as the titanium oxide particles described above and / or a phosphor. When a coloring agent is used, it is preferable to use it in combination with at least one selected from inorganic oxide particles such as the titanium oxide particles described above, a pearling agent, and a phosphor.

[0035] Examples of pearlescent agents include titanium mica (titanium mica), iron oxide-coated titanium mica, carmine-coated titanium mica, carmine- and ferric iron oxide-coated titanium mica, iron oxide- and carmine-treated titanium mica, ferric iron oxide-treated titanium mica, iron oxide- and ferric iron oxide-treated titanium mica, chromium oxide-treated titanium mica, black titanium oxide-treated titanium mica, acrylic resin-coated aluminum powder, silica-coated aluminum powder, silica-coated mica, titanium oxide-coated mica, titanium oxide-coated bismuth oxychloride, titanium oxide-coated talc, colored titanium oxide-coated mica, titanium oxide-coated synthetic mica, titanium oxide-coated silica, titanium oxide-coated alumina, titanium oxide-coated glass powder, polyethylene terephthalate-polymethyl methacrylate laminated film powder, bismuth oxychloride, fish scale foil, iron oxide-coated titanium oxide-coated mica such as red iron oxide-coated titanium oxide-coated mica, and hollow titanium oxide powder having silica sandwiched between the mica and titanium oxide coating layer. These are typically white or another color.

[0036] Colorless pearlescent agents can also be used. Examples of such pearlescent agents include those known as transparent pearlescent agents (transparent luster pigments). For example, pearlescent agents can be used that use glass particles as a base material and have a coating formed on the surface of the particles, the coating being made of a high refractive index material such as titanium oxide.

[0037] As the coloring material, for example, an inorganic pigment can be used.

[0038] Examples of inorganic pigments include inorganic red pigments (e.g., iron oxide (red iron oxide), iron titanate, etc.); inorganic brown pigments (e.g., γ-iron oxide, etc.); inorganic yellow pigments (e.g., yellow iron oxide, ochre, etc.); inorganic black pigments (e.g., black iron oxide, low-order titanium oxide, etc.); inorganic purple pigments (e.g., manganese violet, cobalt violet, etc.); inorganic green pigments (e.g., chromium oxide, chromium hydroxide, cobalt titanate, etc.); inorganic blue pigments (e.g., ultramarine, Prussian blue, etc.); and metal powders (e.g., aluminum, gold, silver, copper, etc.).

[0039] The phosphor may be, for example, MnCl ２ (red), Sm ２ (SO ４ ) ３ ・8H ２ O (orange), CaWO ４ (blue), MgWO ４ (blue-white), CaMoO ４ (yellow-green), KCl:Tl (blue-green), NaCl:Mn (red), ZnO:Zn (white-green), CaS:Bi (purple), ZnS:Cu (yellow-green), ZnS:Ag (purple), Zn ２ SiO ４ : Mn (green), Ca ３ (P.O. ４ ) ２ :Ce:Mn (red), Y ２ O ３ : Eu, YVO ４ : Eu, Y ２ O ２ S: Eu, (Y, Cd)BO ３ :Eu, 0.5MgF ２ GeO ２ : Mn, Zn ２ GeO ４ :Mn, ZnS:Cu, ZnS:Cu,Al, (Zn,Cd)S:Cu,Zn ２ SiO ４ :Mn, BaMgAl １４ O ２３ :Eu ２＋ , Mn ２＋ , SrGa ２ S ４ :Eu２＋ , ZnS:Cu, Co, ZnS:Ag, Cu, Y ２ SiO ５ :Ca, ZnS:Ag, Ga, Cl, Ga ２ B ５ O ９ Cl:Eu ２＋ BaMgAl １４ O ２３ :Eu ２＋ , (Zn, Cd)S:Ag, (Zn,Cd)S:Ag,Al, (Zn,Cd)S:Au,Al, ZnS:Cu,Au,Al,Zn( S, Se): Ag, Zn (S, Se): Ag, Al, Zn (S, Se): Cu, Zn (S, Se): Cu, Al, ZnO: Zn, Zn ２ SiO ４ :Mn, ZnS:Ag, Cu, ZnS:Pb, Cu, Gd ２ O ２ S: Tb, La ２ O ２ S: Tb, Y ３ Al ５ O １２ :Ce, (Y,Gd)3Al ５ O １２ : Ce, SrGa ２ S ４ : Eu, Y ２ O ２ S: Tb, Y ２ SiO ５ :Tb, 3.5MgGeO ２ :Mn, 3BaMgO・8Al ２ O ３ :Eu ２＋ , Mn ２＋ , 3BaMgO・8Al ２ O ３ :Eu ２＋ In addition, for example, In ２ O ３ Examples of suitable phosphors include a luminescent composition containing a predetermined amount of ZnO and ZnS:Ag, and a luminescent composition containing a predetermined amount of ZnO and ZnS:Ag phosphor. Among these, zinc oxide phosphor (ZnO:Zn) is preferred from the viewpoint of safety. Zinc oxide phosphors can be obtained by firing zinc oxide in a reducing atmosphere such as H2 or CO2. In addition, magnesium titanate phosphors can also be suitably used.

[0040] <Oil Droplets> The oil-in-water emulsion cosmetic of the present disclosure contains oil droplets having an average particle size of 1 μm or less in a dispersion medium.

[0041] From the viewpoint of emulsion stability of the cosmetic, the average particle size of the oil droplets is preferably 900 nm or less, 850 nm or less, 800 nm or less, 750 nm or less, 700 nm or less, or 650 nm or less. There is no particular restriction on the lower limit of the average particle size of the oil droplets, and it can be, for example, 100 nm or more, 200 nm or more, 300 nm or more, 400 nm or more, or 450 nm or more. The average particle size of the oil droplets can be defined as the average value of the diameters of the oil droplets optically measured by dynamic light scattering, assuming that the particle shape of the oil droplets is spherical.

[0042] The oil phase or oil droplets serving as the dispersed phase in an oil-in-water emulsion cosmetic typically contain an oil component.

[0043] (Oil Content) The oil content in the oil-in-water emulsion cosmetic of the present disclosure is not particularly limited, and can be, for example, 1.0% by mass or more, 2.0% by mass or more, 3.0% by mass or more, 5.0% by mass or more, 7.0% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, or 30% by mass or more, relative to the total amount of the cosmetic, and can also be 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less.

[0044] A cosmetic composition containing a high amount of oil, for example, 20% by mass or more, can increase the content of, for example, an ultraviolet absorber that can be blended into the oil phase, thereby further improving the ultraviolet protection effect (SPF).

[0045] The type of oil is not particularly limited, and for example, volatile oils and non-volatile oils can be used. The oils can be used alone or in combination of two or more. Here, "volatile" refers to a material that exhibits a volatile content of more than 5% when left at 105°C under atmospheric pressure for 3 hours. From the viewpoint of film uniformity, the volatile content, which serves as an indicator of volatility, is preferably 10% or more, 20% or more, 40% or more, 50% or more, 60% or more, 80% or more, or 100%. Alternatively, the boiling point at 1 atmosphere (101.325 kPa) can be used as an indicator of volatility. From the viewpoint of film uniformity, the boiling point is preferably 250°C or less, 240°C or less, or 230°C or less, and is preferably 80°C or more, 100°C or more, 120°C or more, 150°C or more, or 160°C or more. In addition, in the present disclosure, "non-volatile" refers to a material that exhibits a volatile content of 5% or less when left at 105°C for 3 hours.

[0046] The volatile oil is not particularly limited, and examples thereof include volatile silicone oils and volatile hydrocarbon oils. The volatile oils may be used alone or in combination.

[0047] Examples of volatile silicone oils include volatile acyclic silicone oils and volatile cyclic silicone oils, with volatile acyclic silicone oils being preferred.

[0048] As the volatile acyclic silicone oil, for example, a volatile linear silicone oil and a volatile branched silicone oil can be used.

[0049] Examples of volatile linear silicone oils include low-molecular-weight linear dimethylpolysiloxanes such as dimethylpolysiloxane with a viscosity of 0.65 cSt (sometimes referred to as "dimethicone"), dimethylpolysiloxane with a viscosity of 1 cSt, dimethylpolysiloxane with a viscosity of 1.5 cSt, and dimethylpolysiloxane with a viscosity of 2 cSt. Here, these viscosities refer to kinematic viscosities in an atmosphere at 25°C.

[0050] Examples of volatile branched silicone oils include branched siloxanes such as methyl trimethicone, tris(trimethylsilyl)methylsilane, tetrakis(trimethylsilyl)silane, and caprylyl trimethicone.

[0051] Volatile cyclic silicone oils include, for example, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane.

[0052] Volatile hydrocarbon oils can include, for example, heptane, isododecane, isohexadecane, and isodecane.

[0053] The amount of volatile oil in the oil content can be, for example, 0% by mass or more, 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more, or 45% by mass or more, or 90% by mass or less, 85% by mass or less, 80% by mass or less, 75% by mass or less, 70% by mass or less, 65% by mass or less, 60% by mass or less, 55% by mass or less, or 50% by mass or less, relative to the total oil content. In this case, the remaining oil content can be non-volatile oil.

[0054] In addition to the volatile oils described above, examples of oils include oils commonly used in cosmetics, such as liquid oils, solid oils, waxes, hydrocarbon oils other than those described above, silicone oils other than those described above, polar oils, and higher fatty acids. When other oils (e.g., non-volatile oils) are used in combination with volatile oils, after the volatile oil evaporates, the other oils can function as binders between the particles and the skin, thereby favorably fixing the particles to the skin. The other oils can be used alone or in combination of two or more. Among these oils, polar oils can be favorably used in the cosmetic composition of the present disclosure. Furthermore, some UV absorbers act as oils, particularly polar oils. Such UV absorbers can also be considered oils. UV absorbers that act as polar oils can also be favorably used in the cosmetic composition of the present disclosure.

[0055] Examples of liquid oils and fats include avocado oil, camellia oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, persic oil, wheat germ oil, camellia oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, Chinese tung oil, Japanese tung oil, jojoba oil, germ oil, and triglycerin.

[0056] Examples of solid fats and oils include cocoa butter, coconut oil, horse fat, hardened coconut oil, palm oil, beef tallow, mutton tallow, hardened beef tallow, palm kernel oil, lard, beef bone fat, Japan wax kernel oil, hardened oil, beef foot fat, Japan wax, and hardened castor oil.

[0057] Examples of waxes include beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, privet wax, spermaceti, montan wax, rice bran wax, lanolin, kapok wax, acetated lanolin, liquid lanolin, sugarcane wax, lanolin fatty acid isopropyl, hexyl laurate, reduced lanolin, jojoba wax, hard lanolin, shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, lanolin fatty acid polyethylene glycol, and POE hydrogenated lanolin alcohol ether.

[0058] Examples of hydrocarbon oils include liquid paraffin, ozokerite, squalane, pristane, paraffin, ceresin, squalene, petrolatum, microcrystalline wax, and olefin oligomers.

[0059] Examples of silicone oils include chain silicones such as dimethylpolysiloxane (dimethicone), methylphenylpolysiloxane (diphenylsiloxyphenyltrimethicone), and methylhydrogenpolysiloxane, all of which have a viscosity of 6 cSt or more.

[0060] As the polar oil, for example, a polar oil having an IOB of 0.10 or more can be used. Examples of such polar oils include isopropyl myristate (IOB value = 0.18), octyl palmitate (IOB value = 0.13), isopropyl palmitate (IOB value = 0.16), butyl stearate (IOB value = 0.14), hexyl laurate (IOB value = 0.17), myristyl myristate (IOB value = 0.11), decyl oleate (IOB value = 0.11), isononyl isononanoate (IOB value = 0.20), and isotridecyl isononanoate (IOB value = 0.11). OB value = 0.15), cetyl ethylhexanoate (IOB value = 0.13), pentaerythrityl tetraethylhexanoate (IOB value = 0.35), diethylhexyl succinate (IOB value = 0.32), dioctyl succinate (IOB value = 0.36), glycol distearate (IOB value = 0.16), glyceryl diisostearate (IOB value = 0.29), neopentyl glycol dicaprate (IOB value = 0.25), diisostearyl malate (IOB value = 0.28 ), trimethylolpropane triisostearate (IOB value = 0.16), glyceryl tri-2-ethylhexanoate (triethylhexanoin) (IOB value = 0.35), trimethylolpropane trioctanoate (IOB value = 0.33), trimethylolpropane triisostearate (IOB value = 0.16), diisobutyl adipate (IOB value = 0.46), N-lauroyl-L-glutamic acid-2-octyldodecyl ester (IOB value = 0.29), adipic acid 2-Hexyldecyl (IOB value=0.16), diisopropyl sebacate (IOB value=0.40), ethylhexyl methoxycinnamate (IOB value=0.28), 2-ethylhexyl palmitate (IOB value=0.13), 2-ethylhexyl ethylhexanoate (IOB value=0.2), triisostearin (IOB value=0.16), PPG-3 dipivalate (IOB value=0.52), and caprylic / capric triglyceride (IOB value=0.33).

[0061] Examples of UV absorbers that can be considered to be oils include UV absorbers with an IOB of 0.10 or more, specifically organic UV absorbers such as ethylhexyl methoxycinnamate, octocrylene, polysilicone-15, t-butyl methoxydibenzoylmethane, ethylhexyl triazone, bisethylhexyloxyphenol methoxyphenyl triazine, diethylaminohydroxybenzoylhexyl benzoate, oxybenzone-3, methylenebisbenzotriazolyltetramethylbutylphenol, homosalate, and ethylhexyl salicylate. These UV absorbers can be used alone or in combination of two or more.

[0062] The IOB value of the polar oil and the UV absorber can be, for example, 0.11 or more, 0.12 or more, or 0.13 or more, and can be 0.50 or less, 0.45 or less, or 0.40 or less. Here, the IOB value is an abbreviation for Inorganic / Organic Balance (inorganic / organic ratio), and is a value representing the ratio of the inorganic value to the organic value, and is an index showing the degree of polarity of the 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).

[0063] Examples of higher fatty acids include stearic acid, lauric acid, myristic acid, behenic acid, isostearic acid, and oleic acid.

[0064] (Polyoxyethylene-Polyoxyalkylene Alkyl Ether Block Polymer) In some embodiments, the oil droplets of the present disclosure contain a polyoxyethylene-polyoxyalkylene alkyl ether block polymer (sometimes simply referred to as a "block polymer"). Such a block polymer functions as a nonionic surfactant and can suitably prepare fine oil droplets with an average particle size of 1 μm or less.

[0065] From the viewpoint of obtaining oil droplets with an average particle size of 1 μm or less, i.e., from the viewpoint of emulsion stability of the cosmetic, the content of the block polymer is preferably 0.05% by mass or more, 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more, relative to the total amount of the cosmetic, and is preferably 3.0% by mass or less, 2.5% by mass or less, 2.0% by mass or less, 1.5% by mass or less, or 1.0% by mass or less.

[0066] As such a block polymer, for example, at least one selected from the group consisting of the following formulas 1 and 2 can be used.

[0067] R １ O-(PO) ｍ - (EO) ｎ -H...Formula 1

[0068] In Formula 1, R １ is a hydrocarbon group having 16 to 18 carbon atoms. Such a hydrocarbon group is preferably a saturated or unsaturated aliphatic hydrocarbon group. Specific examples include palmityl, stearyl, isostearyl, oleyl, and linolyl groups.

[0069] In Formula 1, PO is an oxypropylene group, EO is an oxyethylene group, and PO and EO are added in the form of blocks. There are no particular restrictions on the order in which PO and EO are added. Furthermore, the PO and EO block portion may be composed of not only two-stage blocks but also three or more stages of blocks. Note that PO and EO may also be expressed as "POP" and "POE" in the technical field.

[0070] In Formula 1, m and n represent the average number of moles of PO and EO added, respectively, and satisfy the relationships 70 > m > 4, 70 > n > 10, and n > m. m can be 5 or more, 6 or more, or 8 or more, and can be 60 or less, 50 or less, 40 or less, 30 or less, 20 or less, or 10 or less. n can be 12 or more, 15 or more, 17 or more, or 20 or more, and can be 60 or less, 50 or less, 40 or less, 30 or less, 25 or less, or 20 or less.

[0071] From the viewpoint of emulsion stability of the cosmetic, the weight-average molecular weight of the block polymer of Formula 1 is preferably 800 or more, 900 or more, 1,000 or more, 1,300 or more, or 1,500 or more. There is no particular upper limit to the molecular weight, and from the viewpoint of stickiness resistance, it can be, for example, 5,000 or less, 4,000 or less, or 3,000 or less. Here, the weight-average molecular weight in the present disclosure refers to the weight-average molecular weight in terms of polystyrene as measured by gel permeation chromatography.

[0072] Specific examples of the block polymer represented by Formula 1 include POE(20)POP(8) cetyl ether, POE(20)POP(6) decyltetradecyl ether, and POE(30)POP(6) decyltetradecyl ether. Commercially available block polymers may be used. The block polymer represented by Formula 1 may be used alone or in combination.

[0073] R ２ O-(AO) p - (EO) ｑ -R ３ ...Formula 2

[0074] In Formula 2, R ２ and R ３ may be the same or different and are each a hydrocarbon group having 1 to 4 carbon atoms. Such hydrocarbon groups are preferably saturated aliphatic hydrocarbon groups. Specific examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl groups, with methyl and ethyl being preferred.

[0075] In Formula 2, AO is an oxyalkylene group having 3 to 4 carbon atoms (e.g., an oxypropyl group or an oxybutyl group), EO is an oxyethylene group, and AO and EO are added in the form of blocks. There are no particular restrictions on the order in which AO and EO are added. Furthermore, the AO and EO block portion may be composed of not only two-stage blocks but also three or more stages of blocks. Note that an oxybutyl group corresponding to AO is sometimes expressed as "POB" in the technical field.

[0076] In Formula 1, p and q represent the average number of moles of AO and EO added, respectively, and satisfy the relationships 1≦p≦70, 1≦q≦70, and 0.2<(q / (p+q))<0.8. p can be 2 or more, 4 or more, 8 or more, 10 or more, 13 or more, or 15 or more, and can be 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, or 30 or less. q can be 3 or more, 5 or more, 7 or more, 9 or more, 11 or more, or 13 or more, and can be 65 or less, 55 or less, 50 or less, 45 or less, or 40 or less.

[0077] From the viewpoint of emulsion stability of the cosmetic, the weight-average molecular weight of the block polymer of Formula 2 is preferably 1,000 or more, 1,500 or more, 2,000 or more, 2,500 or more, or 3,000 or more. There is no particular upper limit to the molecular weight, and from the viewpoint of stickiness resistance, it can be, for example, 10,000 or less, 8,000 or less, 6,500 or less, or 5,000 or less.

[0078] The block polymer of Formula 2 may be commercially available or may be produced by a known method. For example, such a block polymer can be obtained by addition polymerization of ethylene oxide and an alkylene oxide having 3 to 4 carbon atoms to a compound having a hydroxyl group, followed by an etherification reaction with an alkyl halide in the presence of an alkali catalyst.

[0079] Specific examples of the block polymer represented by formula 2 include POE (14) POP (7) dimethyl ether, POE (10) POP (10) dimethyl ether, POE (7) POP (12) dimethyl ether, POE (15) POP (5) dimethyl ether, POE (25) POP (25) dimethyl ether, POE (27) POP (14) dimethyl ether, POE (55) POP (28) dimethyl ether, POE (22) POP (40) dimethyl ether, and POE (35) POP (40). dimethyl ether, POE(50)POP(40) dimethyl ether, POE(36)POP(41) dimethyl ether, POE(55)POP(30) dimethyl ether, POE(30)POP(34) dimethyl ether, POE(25)POP(30) dimethyl ether, POE(14)POB(7) dimethyl ether, POE(10)POP(10) diethyl ether, POE(10)POP(10) dipropyl ether, POE(10)POP(10) dibutyl ether. The block polymers represented by formula 2 can be used alone or in combination of two or more.

[0080] <Optional Components> The oil-in-water emulsion cosmetic of the present disclosure may contain various components as appropriate, as long as they do not adversely affect the effects of the present disclosure. Examples of the various components include additives that can be typically incorporated into cosmetics, such as anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants other than the above-mentioned block polymers, moisturizers, thickeners (e.g., water-soluble thickeners, oil-soluble thickeners), water-soluble polymers, oil-soluble polymers, film-forming agents such as siliconized polysaccharides, sequestering agents, lower alcohols such as ethanol, higher alcohols, polyhydric alcohols, various extracts, sugars, amino acids, organic amines, polymer emulsions, chelating agents, UV absorbers other than the above-mentioned UV absorbers (e.g., phenylbenzimidazole sulfonic acid), pH adjusters, neutralizing agents, skin nutrients, vitamins, water-soluble agents applicable to pharmaceuticals, quasi-drugs, cosmetics, etc., buffers, anti-fading agents, preservatives, whitening agents, anti-inflammatory agents, dispersants, transdermal absorption inhibitors, propellants, fillers (e.g., usable powders such as silica), pigments other than the above-mentioned pearlescent agents and pigments that can be used as colorants (e.g., organic pigments), stabilizers, dyes, colorants, fragrances, etc. Optional ingredients can be incorporated into the oil phase and / or the aqueous phase and can be used alone or in combination. Some of these ingredients are described below.

[0081] (Dispersant) In some embodiments, the oil-in-water emulsion cosmetic of the present disclosure contains a polyether-modified silicone (sometimes simply referred to as "polyether-modified silicone") having an HLB of 10.0 or more and 18.0 or less in the dispersion medium. The polyether-modified silicone can function as a dispersant for pigment-grade hydrophobically treated particles. The polyether-modified silicone can be used alone or in combination of two or more types.

[0082] From the viewpoints of dispersibility of pigment-grade hydrophobized particles, emulsion stability of cosmetics, etc., the HLB of the polyether-modified silicone is preferably greater than 10.0, 10.5 or greater, 11.0 or greater, 11.5 or greater, 12.0 or greater, 12.5 or greater, or 13.0 or greater, and is preferably 17.5 or less, 17.0 or less, 16.5 or less, 16.0 or less, 15.5 or less, or 15.0 or less. Here, "HLB" generally refers to a value indicating affinity to water and oil, and is a parameter known as the hydrophilic-lipophilic balance. The HLB of the polyether-modified silicone can be easily determined by the Griffin method. Here, the HLB value according to the Griffin method can be determined by the following formula 3: HLB value = 20 × sum of formula weights of hydrophilic moieties / molecular weight ... formula 3

[0083] The amount of polyether-modified silicone may be set to 0.01% by mass or more, 0.03% by mass or more, or 0.05% by mass or more, relative to the total amount of the cosmetic, from the viewpoints of the dispersibility of pigment-grade hydrophobized particles in the aqueous phase, the emulsion stability and tone-up properties of the cosmetic, etc., and may be set to 1.0% by mass or less, 0.8% by mass or less, 0.5% by mass or less, 0.3% by mass or less, or 0.2% by mass or less.

[0084] From the viewpoints of dispersibility of the pigment-grade hydrophobized particles in the aqueous phase, emulsion stability and tone-up properties of the cosmetic, etc., the mass ratio of the pigment-grade hydrophobized particles to the polyether-modified silicone is, for example, preferably 5 or more, 7 or more, 10 or more, 12 or more, 14 or more, 15 or more, or 17 or more, and is also preferably 70 or less, 65 or less, 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, or 30 or less.

[0085] The type of polyether-modified silicone is not particularly limited as long as it has a specific HLB, and examples thereof include PEG-9 dimethicone, PEG-10 dimethicone, PEG-12 dimethicone, PEG-10 methyl ether dimethicone, PEG-11 methyl ether dimethicone, PEG / PPG-20 / 20 dimethicone, PEG / PPG-20 / 23 dimethicone, and PEG-17 dimethicone. Of these, PEG-11 methyl ether dimethicone is preferred.

[0086] (Thickener) Generally, it is difficult to improve the emulsion stability of an oil-in-water emulsion cosmetic containing a powder, so a thickener, particularly a water-soluble thickener, is usually used to ensure the emulsion stability of such a cosmetic. However, although the incorporation of a thickener may improve the emulsion stability, it is likely to cause a sticky feeling.

[0087] On the other hand, since the emulsion stability of the oil-in-water emulsion cosmetic of the present disclosure can be improved by reducing the average particle size of the oil droplets dispersed in the dispersion medium to 1 μm or less, the cosmetic of the present disclosure does not need to substantially contain a thickener. That is, the thickener may be blended in at a ratio of 1% by mass or less, 0.7% by mass or less, 0.5% by mass or less, 0.1% by mass or less, 0.01% by mass or less, or 0.001% by mass or less relative to the total amount of the cosmetic, but it is advantageous to not use a thickener from the standpoint of stickiness, etc.

[0088] <Viscosity of Cosmetic> In some embodiments, the viscosity of the oil-in-water emulsion cosmetic of the present disclosure, measured at 25°C one day after preparation using the conditions and apparatus described in the Examples below, can be 10,000 mPa·s or less, 9,000 mPa·s or less, 8,000 mPa·s or less, 7,000 mPa·s or less, 6,000 mPa·s or less, 5,000 mPa·s or less, 4,500 mPa·s or less, or 4,000 mPa·s or less, or can be 500 mPa·s or more, 1,000 mPa·s or more, 1,500 mPa·s or more, 2,000 mPa·s or more, 2,500 mPa·s or more, or 3,000 mPa·s or more. The oil-in-water emulsion cosmetic of the present disclosure contains oil droplets with an average particle size of 1 μm or less and has excellent emulsion stability, so it can exhibit good emulsification performance even at such a viscosity. Furthermore, a cosmetic of the present disclosure that exhibits such a viscosity can exhibit a refreshing and light feel in use, similar to a beauty serum.

[0089] <<Method for Preparing Oil-in-Water Emulsion Cosmetic>> There are no particular limitations on the method for preparing the oil-in-water emulsion cosmetic of the present disclosure, and it can be prepared by known methods such as dispersion methods and aggregation methods.

[0090] The dispersion method is a method of mechanically breaking down clumps of the dispersed phase into smaller particles. Specifically, it is a method of emulsifying by utilizing the crushing force of an emulsifier, and an example of such a method is a high-pressure emulsification method in which high shear force is applied using a high-pressure homogenizer.

[0091] The aggregation method is a colloid preparation method that utilizes surface chemical properties, in which a uniformly dissolved state is converted into a supersaturated state by some means, resulting in the emergence of a dispersed phase. Specific techniques include the HLB temperature emulsification method, phase inversion emulsification method, non-aqueous emulsification method, D-phase emulsification method, and liquid crystal emulsification method. Among these, the non-aqueous emulsification method (sometimes referred to as the "fine emulsification method"), which uses a hydrophilic solvent such as a polyhydric alcohol in the presence (or absence) of a small amount of water, is preferred.

[0092] Formulation of Oil-in-Water Emulsion Cosmetic There are no particular limitations on the formulation of the oil-in-water emulsion cosmetic of the present disclosure, and examples thereof include liquid, emulsion, cream, gel, spray, and mousse. Here, in the present disclosure, "spray" can include mist-type sprays, aerosol-type sprays, etc.

[0093] <<Uses of Oil-in-Water Emulsion Cosmetics>> The oil-in-water emulsion cosmetic of the present disclosure can be used, for example, as a cosmetic to be applied by spreading it on the skin, etc. Here, cosmetics to be applied to the skin can also include those known as topical skin preparations.

[0094] The product form of the cosmetics of the present disclosure is not particularly limited, but examples thereof include facial cosmetics such as lotion, serum, emulsion, and pack; makeup cosmetics such as foundation, lipstick, and eye shadow; sunscreen cosmetics (sunscreen agents); body cosmetics; hair cosmetics such as hair liquid, hair tonic, hair conditioner, shampoo, rinse, and hair growth agent; ointments, etc.

[0095] The oil-in-water emulsion cosmetic of the present disclosure will be described in more detail below using examples, but the cosmetic of the present disclosure is not limited to these. Note that, hereinafter, unless otherwise specified, the blending amounts are expressed in mass %.

[0096] Examples 1 to 9 and Comparative Examples 1 to 4 The oil-in-water emulsion cosmetics obtained by the formulations shown in Tables 1 to 3 and the production methods shown below were subjected to the following tests, and the results are shown in Tables 1 to 3.

[0097] <Evaluation Method> (Average Particle Size Evaluation Test) Using a Zetasizer (Zetasizer Nano ZS (Sysmex Corporation)), the average particle size of emulsion particles (oil droplets) in the oil-in-water emulsion cosmetic before adding the powder parts was measured by dynamic light scattering. Here, "≧10 μm" in Table 3 indicates that the average particle size of the emulsion particles is approximately 10 μm, which is near the measurement limit. Visual observation with an optical microscope also confirmed that the particle size of the emulsion particles in Comparative Examples 3 and 4 was approximately 10 μm.

[0098] (Rolling Stability Test: Emulsion Stability) The prepared cosmetic was placed in a 50 mL transparent sample tube (diameter 3 cm), and the sample tube was rotated at a speed of 45 rpm in an atmosphere of 25°C for 4 hours, and the state of particle aggregation was visually observed and evaluated according to the following criteria. Here, ratings A to B can be considered as passing, and ratings C to D as failing.

[0099] A: No color stripes associated with particle agglomerates were observed. B: Color stripes associated with particle agglomerates were only slightly observed. C: Color stripes associated with particle agglomerates were only slightly observed. D: Color stripes associated with particle agglomerates were clearly observed.

[0100] (Tone-up Evaluation Test) The prepared cosmetic was applied to the arm, the moisture was dried, the applied surface of the cosmetic was visually observed, and the state of tone-up was evaluated according to the following criteria. Here, ratings A to B can be considered as passing, and ratings C to D as failing. In addition to the tone-up effect, this tone-up test can also indirectly evaluate whether particles such as pigment-grade hydrophobic treated particles have been applied evenly to the skin surface. That is, it can be said that particles such as pigment-grade hydrophobic treated particles have been applied evenly to the skin surface in the order of D, C, B, and A.

[0101] A: There was no unevenness in brightness, and an excellent tone-up effect was achieved. B: There was very slight unevenness in brightness, but a good tone-up effect was achieved. C: There was slight unevenness in brightness, and a good tone-up effect was not achieved. D: There was obvious unevenness in brightness, and a good tone-up effect was not achieved.

[0102] (Evaluation test of particle dispersibility) The prepared cosmetic was placed in a 50 mL transparent sample tube (diameter 3 cm), and after storage at 25°C for 7 days, the state of particle dispersion was visually observed and evaluated according to the following criteria.

[0103] A: No sediment of pigment-grade hydrophobic treated particles was observed. B: A very slight sediment of pigment-grade hydrophobic treated particles was observed. C: A slight sediment of pigment-grade hydrophobic treated particles was observed. D: A clear sediment of pigment-grade hydrophobic treated particles was observed.

[0104] (Evaluation Test for Usability) Three expert panelists comprehensively evaluated the usability (stickiness) of each cosmetic when it was directly applied to the face, using the following evaluation criteria.

[0105] A: No stickiness felt. B: Almost no stickiness felt. C: Slight stickiness felt. D: Stickiness felt.

[0106] (Viscosity Evaluation Test) The viscosity of the cosmetic preparations one day after preparation was evaluated using a B-type viscometer (TVB-type viscometer TVB-10, manufactured by Toki Sangyo Co., Ltd.) under conditions of rotor number 3, 25°C, and 12 rpm. Note that the viscosity of the cosmetic preparation of Comparative Example 2 was not measured because it had separated.

[0107] <Method for producing cosmetics> Oil-in-water emulsion cosmetics were produced by the following method using the formulations shown in Tables 1 to 3. Here, the numbers shown below correspond to the numbers on the left side indicating the names of the ingredients in the formulations in Tables 1 to 3.

[0108] Example 1 Materials Nos. 2 to 13 were added to a portion of the ion-exchanged water No. 1 and mixed uniformly to obtain an aqueous phase part.

[0109] Materials No. 24 to No. 27 were mixed uniformly to obtain an oil phase part.

[0110] The remaining ion-exchanged water from No. 1 was uniformly mixed with the materials from No. 14, No. 15, No. 17, and No. 18 to obtain powder parts.

[0111] The oil phase part was gradually added to the aqueous phase part, and then the powder part was gradually added, and the mixture was uniformly dispersed using a homomixer to obtain the oil-in-water emulsion cosmetic of Example 1.

[0112] Examples 2 to 9 and Comparative Examples 1 to 2 Oil-in-water emulsion cosmetics of Examples 2 to 9 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that the formulations were changed as shown in Tables 1 to 3.

[0113] (Comparative Example 3) An oil-in-water emulsion cosmetic of Comparative Example 3 was obtained in the same manner as in Example 1, except that a nonionic surfactant was not used. Note that in the cosmetic of Comparative Example 3, an (acrylates / C10-30 alkyl acrylate) crosspolymer, which also has emulsifying ability, acts as an active agent.

[0114] (Comparative Example 4) An oil-in-water emulsion cosmetic of Comparative Example 4 was obtained in the same manner as in Comparative Example 3, except that the blending amounts of the water-soluble thickeners (dimethylacrylamide / sodium acryloyldimethyltaurate) crosspolymer and succinoglycan were changed.

[0115]

[0116]

[0117]

[0118] <Results> The results in Tables 1 and 2 confirm that the oil-in-water emulsion cosmetics of Examples 1 to 9, which contain oil droplets with an average particle size of 1 μm or less and pigment-grade hydrophobized particles in a dispersion medium, have excellent emulsion stability and tone-up properties. Furthermore, the cosmetics of Examples 1 to 4 and Examples 7 to 9 did not feel sticky and exhibited a refreshing, light feel in use similar to a beauty serum. Here, the cosmetics of Examples 5 and 6 felt slightly sticky, but this is thought to be due to the increased amount of polyether-modified silicone or glycerin blended compared to the other Examples.

[0119] The cosmetic of Comparative Example 1, which used untreated particles, was rated B in the rolling stability test, even though the size was equivalent to that of pigment-grade hydrophobic treated particles. This is thought to be due to the fact that the hydrophilic portion of the surfactant covers the oil droplets, and therefore untreated hydrophilic particles are more likely to adhere to the oil droplets than pigment-grade hydrophobic treated particles. Furthermore, it is thought that hydrophilic particles are less likely to remain on the lipophilic skin surface than pigment-grade hydrophobic treated particles, and are more likely to fall off from the skin surface, so a good tone-up effect was not achieved.

[0120] From the results of Comparative Examples 3 and 4, when the particle size of the oil droplets is large, increasing the viscosity of the cosmetic improves the emulsion stability somewhat, but still to an unacceptable level, and no improvement in tone-up properties was observed.

[0121] Formulation Examples of Oil-in-Water Emulsion Cosmetics Formulation examples of oil-in-water emulsion cosmetics of the present disclosure are shown in Table 4 below, but the present invention is not limited to these examples. Each cosmetic was prepared in the same manner as in Example 1 above, except for the formulations shown in Table 4. The lotions described in the following formulation examples were excellent in emulsion stability and tone-up effect.

[0122]

[0123] 10, 20 Pigment-grade hydrophobic treated particles 12, 22 Oil droplets 14, 24 Water 30, 40 Pigment-grade hydrophobic treated particles 32, 42 Oil 34, 44 Water

Claims

1. A dispersion medium containing water, and Oil droplets dispersed in the dispersion medium An oil-in-water emulsion cosmetic comprising: The dispersion medium contains pigment-grade hydrophobically treated particles, The average particle size of the oil droplets is 1 μm or less. Oil-in-water emulsion cosmetic.

2. The cosmetic preparation according to claim 1 , wherein the oil droplets contain a polyoxyethylene-polyoxyalkylene alkyl ether block polymer as a nonionic surfactant.

3. The cosmetic preparation according to claim 2, wherein the block polymer is at least one selected from the group consisting of the following formula 1 and formula 2: R １ O-(PO) ｍ -(EO) ｎ -H... Formula 1 In formula 1, R １ is a hydrocarbon group having 16 to 18 carbon atoms, PO is an oxypropylene group; EO is an oxyethylene group; PO and EO are added in blocks. m and n respectively mean the average number of moles of PO and EO added, and satisfy the relationships 70>m>4, 70>n>10, and n>m. R ２ O-(AO) p -(EO) ｑ -R ３ ... Formula 2 In formula 2, R ２ and R ３ may be the same or different and are each a hydrocarbon group having 1 to 4 carbon atoms, AO is an oxyalkylene group having 3 to 4 carbon atoms; EO is an oxyethylene group; AO and EO are added in blocks, p and q respectively mean the average number of moles of AO and EO added, and satisfy the relationships 1≦p≦70, 1≦q≦70, and 0.2<(q / (p+q))<0.

8.

4. The cosmetic preparation according to any one of claims 1 to 3, wherein the dispersion medium contains a polyether-modified silicone having an HLB of 10.0 or more and 18.0 or less.

5. 5. The cosmetic preparation according to claim 4, wherein a mass ratio of said pigment-grade hydrophobized particles to said polyether-modified silicone is 5.0 or more.

6. The cosmetic preparation according to any one of claims 1 to 3, further comprising an ultraviolet absorbing agent.

7. The cosmetic preparation according to any one of claims 1 to 3, wherein the pigment-grade hydrophobized particles have an average particle size of 250 nm or more.

8. The cosmetic preparation according to any one of claims 1 to 3, having a viscosity of 10,000 mPa·s or less.