CN117320681A

CN117320681A - Oil-in-water type emulsified cosmetic

Info

Publication number: CN117320681A
Application number: CN202280035948.3A
Authority: CN
Inventors: 直井香代子; 松井礼奈; 西春佳
Original assignee: Shiseido Co Ltd
Current assignee: Shiseido Co Ltd
Priority date: 2021-06-17
Filing date: 2022-06-03
Publication date: 2023-12-29
Also published as: JPWO2022264840A1; WO2022264840A1

Abstract

An oil-in-water emulsion cosmetic excellent in emulsion stability and lightening properties, which comprises pigment-grade hydrophobicized particles. The oil-in-water emulsion cosmetic of the present disclosure comprises: a dispersion medium containing water, and oil droplets dispersed in the dispersion medium, wherein the dispersion medium contains pigment-grade hydrophobicized particles, and the average particle diameter of the oil droplets is 1 μm or less.

Description

Oil-in-water type emulsified cosmetic

Technical Field

The present disclosure relates to oil-in-water emulsion cosmetics.

Background

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

Patent document 1 discloses an O/W emulsion composition comprising the following components (a) to (c), wherein the oil phase containing the component (a) has an average particle diameter of 700nm or less:

(a) An organic ultraviolet absorber which is oily at 20 ℃ and comprises the following (a 1):

(a1) Oracle

(b) An organic ultraviolet absorber which is solid at 20 ℃ selected from the following (b 1) and (b 2):

(b1) Diethylhexyl oxyphenol methoxyphenyl triazine

(b2) Methylene bis-benzotriazole-based tetramethyl butyl phenol

(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)

[ formula, R ₁ Is a hydrocarbon group having 16 to 18 carbon atoms, PO is an oxypropylene group, and EO is an oxyethylene group. PO is added in blocks with EO. m and n are average addition mole numbers of PO and EO, respectively, 70 > m > 4, 70 > n > 10 and n > m.]

R ₂ O-(AO)p-(EO)q-R ₃ …(2)

[ formula, R ₂ 、R ₃ And may 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, and EO is an oxyethylene group. AO is added in blocks with EO. p and q are average addition mole numbers of AO and EO, p is not less than 1 and not more than 70, q is not less than 1 and not more than 70, and 0.2 < (q/(p+q)) < 0.8.]

Patent document 2 discloses an oil-in-water emulsion type composition comprising i) at least 1 polymer containing sulfonic acid groups, ii) a polysaccharide modified with a hydrophobic chain, iii) at least 1 (meth) acrylic polymer, and/or 1 silicone surfactant selected from oxyethylenated polydimethylsiloxanes, and a pigment and/or a filler in a physiologically acceptable aqueous medium.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2010-132647

Patent document 2: japanese patent application laid-open No. 2016-52975

Disclosure of Invention

Problems to be solved by the invention

In the case of mixing particles subjected to hydrophobization, for example, in an oil-in-water emulsion cosmetic, generally, such particles are mixed in an oil phase (oil droplets). Furthermore, as described in patent document 2 ([ 0010 ]), it is known in the art that the use of powder (e.g., pigment or filler) destabilizes the emulsifying performance of an oil-in-water type emulsified cosmetic.

For example, pigment-grade hydrophobized particles having a relatively large size may be used as hydrophobized particles blended in an oil-in-water emulsion cosmetic for the purpose of exhibiting a lightening effect for lightening the skin.

When the oil-in-water emulsion cosmetic containing such particles subjected to hydrophobization in an oil phase (oil droplets) is applied to skin, the oil droplets containing the particles subjected to hydrophobization are adsorbed in the skin's skin hills or skin furrows having high surface activity in a state where the oil is pulled by the particles, and are likely to stay. As a result, the oil containing the particles subjected to the hydrophobization (for example, pigment-grade hydrophobization particles) is not easily and uniformly applied to the skin, and thus uneven lightening may occur.

Accordingly, the subject matter of the present disclosure is to provide an oil-in-water type emulsified cosmetic material comprising pigment-grade hydrophobicized particles, which is excellent in emulsion stability and lightening.

Means for solving the problems

Scheme 1

An oil-in-water emulsified cosmetic comprising:

dispersion medium comprising water, and method for producing a dispersion medium

Oil droplets dispersed in the dispersion medium,

the dispersion medium comprises pigment-grade hydrophobicized particles,

The average particle diameter of the oil droplets is 1 μm or less.

Scheme 2

The cosmetic according to scheme 1, the oil droplets comprising a polyoxyethylene/polyoxyalkylene alkyl ether block polymer as a nonionic surfactant.

Scheme 3

The cosmetic according to scheme 2, wherein the block polymer is at least one selected from the following formulas 1 and 2,

R ¹ O-(PO) _m -(EO) _n -H … type 1

In the formula (1) of the present invention,

R ¹ is a hydrocarbon group having 16 to 18 carbon atoms,

PO is an oxypropylene group and the oxygen is propylene,

EO is an oxyethylene group and the oxygen content of the EO,

the PO and EO are added in a block-like manner,

m and n refer to average addition mole numbers of PO and EO, respectively, and satisfy the relationships of 70 > m > 4, 70 > n > 10, and n > m.

R ² O-(AO) _p -(EO) _q -R ³ … type 2

In the formula (2) of the present invention,

R ² and R is ³ Can be the same or different and are respectively hydrocarbon groups with 1 to 4 carbon atoms,

AO is an oxyalkylene group having 3 to 4 carbon atoms,

EO is an oxyethylene group and the oxygen content of the EO,

the AO and EO are added in a block-like manner,

p and q refer to average addition mole numbers of AO and EO, respectively, and satisfy the relationships of 1.ltoreq.p.ltoreq.70, 1.ltoreq.q.ltoreq.70, and 0.2 < (q/(p+q)) < 0.8.

Scheme 4

The cosmetic according to any one of aspects 1 to 3, wherein the dispersion medium comprises a polyether-modified silicone having an HLB of 10.0 to 18.0.

Scheme 5

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

Scheme 6

The cosmetic according to any one of aspects 1 to 5, which comprises an ultraviolet absorber.

Scheme 7

The cosmetic according to any one of aspects 1 to 6, wherein the pigment-grade hydrophobized particles have an average particle diameter of 250nm or more.

Scheme 8

The cosmetic according to any one of the aspects 1 to 7, which has a viscosity of 10,000 mPas or less.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present disclosure, an oil-in-water type emulsified cosmetic composition containing pigment-grade hydrophobicized particles, which is excellent in emulsion stability and lightening properties, can be provided.

Drawings

Fig. 1 (a) is a schematic view showing the state in which oil droplets (emulsified particles) collide with each other and are integrated in the rolling stability test, and (b) is a schematic view showing the state in which pigment-grade hydrophobized particles are attached to the surface of coarsened oil droplets after the rolling stability test.

Fig. 2 (a) is a schematic diagram showing the states of oil droplets (emulsified particles) and pigment-grade hydrophobized particles in the rolling stability test, and (b) is a schematic diagram showing the states of oil droplets and pigment-grade hydrophobized particles after the rolling stability test.

Fig. 3 (a) is a schematic diagram of an oil-in-water emulsion cosmetic according to an embodiment of the present disclosure, (b) is a schematic diagram of a state in which the cosmetic is applied to skin and moisture is dried, and (c) is a schematic diagram of a state in which the cosmetic is applied to skin.

Fig. 4 (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 a skin-friendly state of the cosmetic.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described in detail. The present disclosure is not limited to the following embodiments, and can be implemented by various modifications within the scope of the invention.

The oil-in-water emulsion cosmetic of the present disclosure comprises: a dispersion medium containing water, and oil droplets dispersed in the dispersion medium, wherein the dispersion medium contains pigment-grade hydrophobicized particles, and the average particle diameter of the oil droplets is 1 μm or less.

Although not limited by the principle, the cosmetic of the present disclosure is considered to have the following principle of action that is excellent in emulsion stability and lightening property even when it contains pigment-grade hydrophobicized particles.

As described above, it is known that the use of powders (e.g., pigments and fillers) generally destabilizes the emulsifying performance of oil-in-water type emulsified cosmetics. However, the present inventors have found that if the average particle diameter of oil droplets (emulsified particles) in a cosmetic is 1 μm or less, the emulsion stability of an oil-in-water emulsion cosmetic is improved even if pigment-grade hydrophobicized particles are contained in a dispersion medium.

It is considered that if the size of oil droplets (emulsified particles) in the oil-in-water type emulsified cosmetic material is large, as shown in fig. 1, for example, when a rolling stability test is performed, the oil droplets 12 collide with each other and are likely to be integrated. As a result, it is considered that the pigment-level hydrophobicized particles 10 adhere to the surface of the coarsened oil droplets 12, and the emulsion balance is broken down, so that the emulsion stability of the oil droplets is lowered. Further, it was observed by an optical microscope that pigment-grade hydrophobicized particles were attached to the surface of coarsened oil droplets.

On the other hand, if the size of the oil droplets in the oil-in-water emulsion cosmetic is small, as shown in fig. 2, for example, even if the rolling stability test is performed, the oil droplets 22 are unlikely to collide with each other and to be integrated with each other, as compared with the case of large-sized oil droplets. As a result, it is considered that the pigment-level hydrophobizing particles 20 are less likely to adhere to the surfaces of the oil droplets 22 than in the case of large-sized oil droplets, and therefore the emulsion stability of the oil droplets is improved.

In addition, as described above, in the case of obtaining an oil-in-water type emulsified cosmetic material containing hydrophobicized particles, the hydrophobicized particles are generally blended in an oil phase because they are hydrophobic. However, the present inventors have found that, in an oil-in-water emulsion cosmetic, if pigment-grade hydrophobicized particles are blended in an aqueous phase, the lightening effect is improved when such a cosmetic is applied to the skin.

In the conventional oil-in-water emulsion cosmetic containing pigment-based hydrophobicized particles in the oil phase, it is considered that the pigment-based hydrophobicized particles 40 are densely deposited in the oil phase as shown in fig. 4 (a).

It is considered that when such an oil-in-water emulsion cosmetic containing pigment-level hydrophobizing particles in an oil phase is applied to skin, as shown in fig. 4 (b), pigment-level hydrophobizing particles 40 and oil 42 are unevenly adsorbed in the skin hills or skin furrows, which are lipophilic and have high surface activity, in a densely packed state.

On the other hand, in the oil-in-water emulsion cosmetic of the present disclosure containing pigment-grade hydrophobized particles in the aqueous phase, it is considered that if such a cosmetic is applied to the skin, the pigment-grade hydrophobized particles 30 are likely to be uniformly adsorbed on the skin and stay as shown in fig. 3 (b) as compared with the oil-in-water emulsion cosmetic containing pigment-grade hydrophobized particles in the oil phase. As a result, it is considered that since pigment-grade hydrophobized particles contributing to the lightening effect are uniformly arranged on the skin, the lightening effect is improved as compared with an oil-in-water emulsion cosmetic containing pigment-grade hydrophobized particles in the oil phase.

Further, it is considered that if the average particle diameter of oil droplets (emulsified particles) in the cosmetic is 1 μm or less, for example, pigment-level hydrophobized particles adhere to the skin in a state where the intervals between the particles shown in fig. 3 (b) become denser, as compared with the case where a cosmetic containing oil droplets having an average particle diameter of 10 μm is used. As a result, the effect of lightening is also considered to be improved. The improvement in the lightening effect can be said to mean that pigment-grade hydrophobized particles uniformly adhere to the skin, and thus the ultraviolet protection effect (SPF) is similarly improved.

Oil-in-water type emulsified cosmetic

Dispersion medium

The dispersion medium (aqueous phase) in the oil-in-water emulsion cosmetic of the present disclosure contains water, pigment-grade hydrophobicized particles.

(Water)

The mixing amount of water is not particularly limited, and may be 30 mass% or more, 40 mass% or more, 50 mass% or more, 60 mass% or more, 70 mass% or more, or 80 mass% or more, or 90 mass% or less, 80 mass% or less, 70 mass% or less, or 60 mass% or less, for example, with respect to the total amount of the cosmetic from the viewpoint of emulsion stability or the like.

The water that can be used in the oil-in-water emulsion cosmetic of the present disclosure is not particularly limited, and for example, water that is used in cosmetics and quasi drugs can be used. For example, ion-exchanged water, distilled water, ultrapure water, and tap water may be used.

(pigment-grade hydrophobized particles)

The blending amount of the pigment-grade hydrophobizing particles is not particularly limited, and may be appropriately selected based on a desired effect (for example, a lightening effect or SPF) according to the application. The mixing amount of the pigment-grade hydrophobizing particles may be, for example, 0.5 mass% or more, 1.0 mass% or more, or 1.5 mass% or more, or 15 mass% or less, 12 mass% or less, 10 mass% or less, 8.0 mass% or less, 6.0 mass% or less, or 5.0 mass% or less, based on the total amount of the cosmetic.

The average particle diameter of the pigment-grade hydrophobized particles can be appropriately selected so as to obtain a desired effect (for example, a lightening effect, SPF) according to the application. The average particle diameter of the pigment-grade hydrophobized particles may be, for example, 250nm or more, 300nm or more, 350nm or more, or 400nm or more. Pigment-grade hydrophobized particles having an average particle diameter of 300nm or more can suitably exhibit a lightening effect or the like that lightens the color of skin. The upper limit of the average particle diameter is not particularly limited, and may 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, 800nm or less, 700nm or 600nm or less. The average particle diameter of the pigment-grade hydrophobized particles in the present disclosure may be the size of the primary particles or the aggregated secondary particles, and may be calculated by a static light scattering method.

The hydrophobizing treatment of the pigment-grade hydrophobizing treated particles is not particularly limited, and examples thereof include any treatment in which the surfaces of such particles are modified with an organic compound to be hydrophobized, for example, an organosilicon-based treatment or a silane-based treatment using methyl hydrogen-containing polysiloxane, dimethylpolysiloxane (polydimethylsiloxane), alkylsilane, or the like; fluorine-based treatments such as perfluoroalkyl phosphate and perfluoroalkyl alcohol are used; titanate treatment such as alkyl titanate treatment; amino acid treatment with N-acyl glutamic acid or the like, and lecithin treatment can be mentioned; metal soap treatment; fatty acid treatment; alkyl phosphate treatment. The hydrophobizing treatment may be used singly or in combination of plural. The hydrophobizing treatment may be performed using a hydrophobizing agent.

Examples of the silicone of the hydrophobizing agent include known silicones having a hydrogen-silicon bond such as methyl hydrogen-containing polysiloxane (polydimethylsiloxane/polymethylsiloxane) copolymer. Further, triethoxysilylethyl polydimethylsiloxane alkoxyethyl polydimethylsiloxane, triethoxysilylethyl polydimethylsiloxane alkoxyethyl hexyl polydimethylsiloxane and the like having an alkoxy-silicon bond as a reactive group can be mentioned. In addition, dimethylpolysiloxane, tetrahydrotetramethylcyclotetrasiloxane, and the like can also be used.

Examples of the silane-based treating agent include a silylating agent having an organic group introduced therein, and a silane coupling agent such as triethoxyoctylsilane.

Examples of the titanate-based treating agent include titanium coupling agents such as alkyl titanate, pyrophosphoric acid type titanate, phosphorous acid type titanate, and amino acid type titanate.

The type of particles constituting the pigment-grade hydrophobized particles is not particularly limited, and may be appropriately selected so as to obtain a desired effect (for example, a lightening effect or SPF) according to the application. Examples of the pigment-grade hydrophobizing particles include inorganic particles, specifically, inorganic oxide particles, for example, white-based inorganic oxide particles (sometimes referred to as "inorganic white-based pigments") such as titanium oxide particles, zinc oxide particles, and cerium oxide particles. In general, inorganic particles classified as pearling agents (luster pigments), coloring materials, or fluorescent materials, or the like, may also be used as pigment-grade hydrophobicized particles of the present disclosure. As pigment-grade hydrophobicized particles of the present disclosure, organic particles may also be used. Pigment-grade hydrophobizing particles may be used singly or in combination of two or more.

In the present disclosure, the term "pearlizing agent" refers to particles that do not contain coloring materials or fluorescent materials, but exhibit brightness. Pearlizing agents typically take the form of flat plates such as flakes or scales. In the present disclosure, the term "coloring material" refers to a material that exhibits a color other than white, does not contain a pearlizing agent or a fluorescent material, and does not exhibit brightness, which can color a cosmetic. For example, from the viewpoint of the effect of lightening, it is preferable to use a pearling agent in combination with the inorganic oxide particles such as titanium oxide particles and/or a fluorescent material, and it is preferable to use a coloring material in combination with at least one selected from the inorganic oxide particles such as titanium oxide particles, pearling agents, and fluorescent materials.

Examples of the pearlizing agent include titanium mica, iron oxide-coated titanium mica, carmine-coated titanium mica, iron oxide-treated titanium mica, carmine-treated titanium mica, iron oxide-treated titanium mica, chromium oxide-treated titanium mica, black titanium oxide-treated titanium mica, acrylic resin-coated aluminum powder, silica-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 aluminum oxide, titanium oxide-coated glass frit, polyethylene terephthalate-polymethyl methacrylate-laminated film powder, bismuth oxychloride, fish scale foil, iron oxide-red titanium oxide-coated mica in which mica is coated with iron oxide and titanium oxide, and titanium oxide-coated iron oxide-red titanium oxide-coated mica, and titanium oxide-coated hollow titanium oxide-coated mica in which silica is sandwiched between mica and titanium oxide-coated layers. They typically appear white, or a color other than white.

As the pearling agent, a colorless pearling agent may be used. As such a pearlescent agent, a known one known as a transparent pearlescent agent (transparent luster pigment) can be used. For example, a pearling agent in which a film made of a high refractive index material such as titanium oxide is formed on the surface of glass particles as a base material.

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

Examples of the inorganic pigment include inorganic red pigments (for example, iron oxide (red iron oxide), iron titanate, and the like); inorganic brown pigments (e.g., gamma-iron oxide); inorganic yellow pigments (e.g., iron oxide yellow, loess, etc.); inorganic black pigments (for example, iron oxide black, titanium suboxide, etc.); inorganic violet pigments (e.g., manganese violet, cobalt violet, etc.); inorganic green pigments (for example, chromium oxide, chromium hydroxide, cobalt titanate, etc.); inorganic blue pigments (e.g., ultramarine blue, dark blue, etc.); metal powders (e.g., aluminum, gold, silver, copper, etc.).

Examples of the phosphor include MnCl ₂ (Red), sm ₂ (SO ₄ ) ₃ ·8H ₂ O (orange), caWO ₄ (blue), mgWO ₄ (bluish white), caMoO ₄ (yellow green), KCl: tl (blue green), naCl: mn (red), znO: zn (white green), caS: bi (violet), znS: cu (yellow green), znS: ag (violet), zn ₂ SiO ₄ Mn (green), ca ₃ (PO 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 :Eu ²⁺ 、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⁺ . Further, for example, a predetermined amount of In is contained ₂ O ₃ A luminescent composition containing a specified amount of ZnO and ZnS: ag phosphor. Among them, zinc oxide phosphor (ZnO: zn) is preferable from the viewpoint of safety. The zinc oxide phosphor can be produced by dispersing zinc oxide in H ₂ And firing under a reducing atmosphere such as CO. In addition, a magnesium titanate phosphor may also be suitably used.

Oil drop

The oil-in-water emulsion cosmetic of the present disclosure contains oil droplets having an average particle diameter of 1 μm or less in a dispersion medium.

From the viewpoint of emulsion stability of the cosmetic, the average particle diameter of the oil droplets is preferably 900nm or less, 850nm or less, 800nm or less, 750nm or less, 700nm or less, or 650nm or less. The lower limit of the average particle diameter of the oil droplets is not particularly limited, and may be, for example, 100nm or more, 200nm or more, 300nm or more, 400nm or more, or 450nm or more. The average particle diameter of the oil droplets can be defined as an average value of the diameters of the oil droplets optically measured by a dynamic light scattering method when the particle shape of the oil droplets is assumed to be spherical.

Oil droplets, which are the oil phase or the dispersed phase in an oil-in-water emulsified cosmetic, typically contain an oil component.

(oil content)

The content of the oil in the oil-in-water emulsion cosmetic of the present disclosure is not particularly limited, and may 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, and further may 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 10% by mass or less, relative to the total amount of the cosmetic.

For example, a cosmetic composition containing an oil component at a high level of 20 mass% or more can have an increased content of, for example, an ultraviolet absorber that can be mixed in an oil phase, and thus can have a further improved ultraviolet protection effect (SPF).

The type of the oil component is not particularly limited, and for example, volatile oil and nonvolatile oil can be used. The oil component may be used singly or in combination of two or more. Here, "volatility" means that the volatile component is more than 5% when left at 105 ℃ for 3 hours under atmospheric pressure. From the viewpoint of film uniformity, the volatile component that becomes a volatile index is preferably 10% or more, 20% or more, 40% or more, 50% or more, 60% or more, 80% or more, or 100% or more. Alternatively, as a volatile index, a boiling point at 1 air pressure (101.325 kPa) may be used. From the viewpoint of film uniformity, the boiling point is preferably 250 ℃ or less, 240 ℃ or less, or 230 ℃ or less, and further preferably 80 ℃ or more, 100 ℃ or more, 120 ℃ or more, 150 ℃ or more, or 160 ℃ or more. In the present disclosure, "nonvolatile" means that the volatile component is 5% or less when left at 105 ℃ for 3 hours.

The volatile oil is not particularly limited, and examples thereof include volatile silicone oils and volatile hydrocarbon oils. The volatile oil may be used singly or in combination of two or more.

Examples of the volatile silicone oil include volatile acyclic silicone oil and volatile cyclic silicone oil. Among them, volatile acyclic silicone oils are preferable.

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

Examples of the volatile linear silicone oil include low molecular weight linear dimethylpolysiloxanes such as dimethylpolysiloxane having a viscosity of 0.65cSt (sometimes referred to as "polydimethylsiloxane"), dimethylpolysiloxane having a viscosity of 1cSt, dimethylpolysiloxane having a viscosity of 1.5cSt, and dimethylpolysiloxane having a viscosity of 2 cSt. Here, their viscosity means the kinematic viscosity under an atmosphere at 25 ℃.

Examples of the volatile branched silicone oil include branched silicones such as methyl trimethicone, tris (trimethylsilyl) methylsilane, tetrakis (trimethylsilyl) silane, and octyl trimethicone.

Examples of the volatile cyclic silicone oil include octamethyl cyclotetrasiloxane, decamethyl cyclopentasiloxane, and dodecamethyl cyclohexasiloxane.

Examples of the volatile hydrocarbon oil include heptane, isododecane, isohexadecane, and isodecane.

The amount of the volatile oil to be mixed in the oil may 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, and may be 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 50% by mass or less, based on the whole oil. The remaining portion of the oil in this case may be a fixed oil.

Examples of the oil component include, in addition to the volatile oil, oil components commonly used in cosmetics, such as liquid oils and fats, solid oils and waxes, hydrocarbon oils other than the above, silicone oils other than the above, polar oils, and higher fatty acids. If other oil components (e.g., non-volatile oil) are used together with the volatile oil, such other oil components can act as an adhesive between the particles and the skin after the volatile oil is volatilized, and thus the particles can be suitably immobilized to the skin. The other oil components may be used singly or in combination of two or more. Among such oil components, the cosmetic of the present disclosure may suitably use polar oil. In addition, there are also substances that function as oil components, particularly polar oils, in the ultraviolet absorber. Such an ultraviolet absorber can also be regarded as an oil component. The cosmetic of the present disclosure may also suitably use an ultraviolet absorber that functions as a polar oil.

Examples of the liquid oils include avocado oil, camellia oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg oil, sesame oil, peach seed oil, wheat germ oil, camellia oil, castor oil, linseed oil, safflower oil, cotton seed oil, perilla oil, soybean oil, peanut oil, tea seed oil, torreya oil, rice bran oil, white tung oil, japan tung oil, jojoba oil, germ oil, and triglycerin.

Examples of the solid fat include cocoa butter, coconut oil, horse fat, hardened coconut oil, palm oil, tallow, mutton fat, hardened tallow, palm kernel oil, lard, beef tallow, wood kernel oil, hardened oil, beef foot fat, wood wax, and hardened castor oil.

Examples of waxes include beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, insect wax, spermaceti wax, montan wax, rice bran wax, lanolin, kapok wax, acetylated lanolin, liquid lanolin, sugarcane wax, isopropyl lanolin fatty acid, 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 ester, and POE hydrogenated lanolin alcohol ether.

Examples of the hydrocarbon oil include liquid paraffin, ceresin, squalane, pristane, paraffin, ceresin, squalene, petrolatum, microcrystalline wax, and olefin oligomer.

Examples of the silicone oil include chain silicones such as dimethylpolysiloxane (polydimethylsiloxane) having a viscosity of 6cSt or more, methylphenylpolysiloxane (diphenylsiloxyphenyl trimethicone), and methyl hydrogen-containing polysiloxane.

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), isotridecyl isononanoate (IOB value=0.15), cetyl ethylhexanoate (IOB value=0.13), pentaerythritol tetraethylhexanoate (IOB value=0.35), diethyl hexyl succinate (IOB value=0.32), dioctyl succinate (IOB value=0.36), diglycol stearate (IOB value=0.16), glyceryl diisostearate (IOB value=0.29), neopentyl glycol stearate (IOB value=0.25), stearyl diisodecyl stearate (IOB value=0.28), trimethylolpropane (IOB value=0.16), trimethylolpropane (IOB value=0.35), and trimethylolpropane (IOB value=0.46 2-hexyldecyl adipate (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), glyceryl triisostearate (IOB value=0.16), PPG-3 dipivalate (IOB value=0.52), and glyceryl tris (caprylic/capric) ate (IOB value=0.33).

Examples of the ultraviolet absorber that can be regarded as an oil component include ultraviolet absorbers having an IOB of 0.10 or more, specifically, organic ultraviolet absorbers such as ethylhexyl methoxycinnamate, octocrylene, polysilicone-15, t-butylmethoxydibenzoylmethane, ethylhexyl triazone, diethylhexyloxyphenol methoxyphenyl triazine, diethylamino hydroxybenzohexyl benzoate, oxybenzone-3, methylenebisbenzotriazole tetramethylbutylphenol, homosalate, and ethylhexyl salicylate. These ultraviolet absorbers may be used singly or in combination of two or more.

The IOB value of the polar oil and the ultraviolet absorber may be, for example, 0.11 or more, 0.12 or more, or 0.13 or more, and may be 0.50 or less, 0.45 or less, or 0.40 or less. Here, the IOB value is a shorthand of an Inorganic/Organic Balance (Inorganic/Organic ratio), and is a value indicating a ratio of an Inorganic value to an Organic value, and is an index indicating a degree of polarity of an Organic compound. The IOB value is specifically expressed as IOB value=inorganic value/organic value. The "inorganic value" and the "organic value" are each set, for example, such that the "organic value" is set to 20 for 1 carbon atom in the molecule and the "inorganic value" is set to 100 for 1 hydroxyl group, and the "inorganic value" and the "organic value" corresponding to each atom or functional group are set, and the "inorganic value" and the "organic value" of all atoms and functional groups in the organic compound are integrated, whereby the IOB value of the organic compound can be calculated (for example, japanese patent publication No. a Tian Shansheng, "available with concept of the invention" group by the use of the term "organic concept graph-basis and application-)", p.11 to 17, three co-publication, 1984).

Examples of the higher fatty acid include stearic acid, lauric acid, myristic acid, behenic acid, isostearic acid, and oleic acid.

(polyoxyethylene/polyoxyalkylene alkyl ether block polymer)

In several embodiments, the oil droplets of the present disclosure comprise a polyoxyethylene/polyoxyalkylene alkyl ether block polymer (sometimes referred to simply as a "block polymer"). Such a block polymer functions as a nonionic surfactant, and can suitably prepare fine oil droplets having an average particle diameter of 1 μm or less.

The content of the block polymer is preferably 0.05 mass% or more, 0.1 mass% or more, 0.2 mass% or more, or 0.3 mass% or more, and further preferably 3.0 mass% or less, 2.5 mass% or less, 2.0 mass% or less, 1.5 mass% or less, or 1.0 mass% or less, with respect to the total amount of the cosmetic, from the viewpoint of obtaining oil droplets having an average particle diameter of 1 μm or less, that is, from the viewpoint of emulsion stability of the cosmetic.

As such a block polymer, for example, at least one selected from the following formulas 1 and 2 can be used.

R ¹ O-(PO) _m -(EO) _n -H … type 1

In formula 1, R ¹ Is a hydrocarbon group having 16 to 18 carbon atoms. As such a hydrocarbon group, a saturated or unsaturated aliphatic hydrocarbon group is preferable. Specifically, for example, palm-based, stearyl, isostearyl, oleyl, and linoleyl are exemplified.

In formula 1, PO is oxypropylene, EO is oxyethylene, and PO and EO are added in block form. The order of addition of PO and EO is not particularly limited. The block portion of PO and EO may be constituted not only by 2 blocks but also by 3 or more blocks. In this technical field, PO and EO are sometimes also referred to as "POP" and "POE".

In formula 1, m and n refer to average addition mole numbers of PO and EO, respectively, satisfying the relationships of 70 > m > 4, 70 > n > 10, and n > m. m may be 5 or more, 6 or more, or 8 or more, and may be 60 or less, 50 or less, 40 or less, 30 or less, 20 or less, or 10 or less. n may be 12 or more, 15 or more, 17 or more, or 20 or more, and may be 60 or less, 50 or less, 40 or less, 30 or less, 25 or less, or 20 or less.

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. The upper limit of the molecular weight is not particularly limited, and may be, for example, 5,000 or less, 4,000 or less, or 3,000 or less from the viewpoint of the hair-sticking resistance. Here, the weight average molecular weight in the present disclosure refers to a polystyrene-equivalent weight average molecular weight in a gel permeation chromatography measurement.

Specific examples of the block polymer represented by formula 1 include POE (20) POP (8) cetyl ether, POE (20) POP (6) decyl tetradecyl ether, and POE (30) POP (6) decyl tetradecyl ether. As such block polymers, commercially available ones can be used. The block polymer represented by formula 1 may be used singly or in combination of two or more.

R ² O-(AO) _p -(EO) _q -R ³ … type 2

In formula 2, R ² And R is ³ May be the same or different and each is a hydrocarbon group having 1 to 4 carbon atoms. As such a hydrocarbon group, a saturated aliphatic hydrocarbon group is preferable. Specifically, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl are cited, and among them, methyl and ethyl are preferable.

In formula 2, AO is an oxyalkylene group having 3 to 4 carbon atoms (for example, an oxypropyl group or an oxybutyl group), EO is an oxyethylene group, and AO and EO are added in a block form. The order of addition of AO and EO is not particularly limited. The blocks of AO and EO may be constituted not only by 2 blocks but also by 3 or more blocks. The oxybutyl group corresponding to AO is also sometimes referred to as "POB" in this technical field.

In formula 1, p and q refer to average addition mole numbers of AO and EO, respectively, satisfying the relationships of 1.ltoreq.p.ltoreq.70, 1.ltoreq.q.ltoreq.70, and 0.2 < (q/(p+q)) < 0.8. p may be 2 or more, 4 or more, 8 or more, 10 or more, 13 or more, or 15 or more, and may be 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, or 30 or less. q may be 3 or more, 5 or more, 7 or more, 9 or more, 11 or more, or 13 or more, and may be 65 or less, 55 or less, 50 or less, 45 or less, or 40 or less.

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. The upper limit of the molecular weight is not particularly limited, and may be, for example, 10,000 or less, 8,000 or less, 6,500 or less, or 5,000 or less from the viewpoint of the hair tack resistance.

The block polymer of formula 2 may be commercially available, or may be produced by a known method. Such a block polymer can be obtained, for example, by adding an alkylene oxide and an alkylene oxide having 3 to 4 carbon atoms to a compound having a hydroxyl group, and then subjecting an alkyl halide to an ether reaction in the presence of a base catalyst.

Specifically, the block polymer represented by formula 2 includes, for example, POP (14) POP (7) dimethyl ether, POP (10) dimethyl ether, POP (7) POP (12) dimethyl ether, POP (15) POP (5) dimethyl ether, POP (25) dimethyl ether, POP (27) POP (14) dimethyl ether, POP (55) POP (28) dimethyl ether, POP (22) POP (40) dimethyl ether, POP (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, POP (25) POP (30) POB (14) dimethyl ether, POP (10) diethyl ether, POE (10) POP (10) diethyl ether, POP (10) propyl POP (10) dimethyl ether. The block polymer represented by formula 2 may be used singly or in combination of two or more.

Arbitrary composition

The oil-in-water emulsion cosmetic of the present disclosure can be appropriately mixed with various components within a range that does not adversely affect the effects of the present disclosure. Examples of the various components include additives which can be usually blended in cosmetics, such as anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants other than the above block polymers, moisturizers, thickeners (e.g., water-soluble thickeners, oil-soluble thickeners), water-soluble polymers, oil-soluble polymers, film formers such as organic siliconized polysaccharides, metal ion blocking agents, lower alcohols such as ethanol, higher alcohols, polyols, various extracts, sugars, amino acids, organic amines, polymer emulsions, chelating agents, other ultraviolet absorbers (e.g., phenylbenzimidazole sulfonic acid) other than the above ultraviolet absorbers, pH adjusters, neutralizing agents, skin nutrients, vitamins, drugs, quasi drugs, water-soluble drugs, buffers, discoloration inhibitors, preservatives, whitening agents, anti-inflammatory agents, colorants, percutaneous absorption inhibitors, propellants, fillers (e.g., silica-like usable powders), pigments other than the above-mentioned agents and usable pigments, such as pigments, and stable pigments, and other pigments. Any component can be mixed in the oil phase and/or the water phase, and can be used singly or in combination of more than two. Several of these components are described below.

(dispersant)

In several embodiments, the oil-in-water emulsion cosmetic of the present disclosure comprises 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 a dispersion medium. The polyether modified silicone can function as a dispersant for pigment-grade hydrophobicized particles. The polyether-modified silicone may be used singly or in combination of two or more.

The HLB of the polyether-modified silicone is preferably more than 10.0, 10.5 or more, 11.0 or more, 11.5 or more, 12.0 or more, 12.5 or more, or 13.0 or more, 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, from the viewpoints of dispersibility of pigment-level hydrophobicized particles, emulsion stability of cosmetics, and the like. The term "HLB" is used herein to mean a value showing affinity for water and oil, and is a parameter known as the hydrophilicity-lipophilicity balance. The HLB of polyether modified silicones can be readily determined by the Griffonia method. Here, the HLB value obtained by the griffonia method can be obtained by the following formula 3:

HLB value = 20 x sum of formula weights of hydrophilic portion/molecular weight … formula 3

The amount of the polyether-modified silicone to be blended may be 0.01 mass% or more, 0.03 mass% or more, or 0.05 mass% or more, or 1.0 mass% or less, 0.8 mass% or less, 0.5 mass% or less, 0.3 mass% or less, or 0.2 mass% or less, based on the total amount of the cosmetic, from the viewpoints of dispersibility of pigment-level hydrophobicized particles in the aqueous phase, emulsion stability of the cosmetic, and brightness.

From the viewpoints of dispersibility of the pigment-based hydrophobicized particles in the aqueous phase, emulsion stability of the cosmetic, and brightness, the mass ratio of the pigment-based hydrophobicized particles to the polyether-modified silicone is preferably, for example, 5 or more, 7 or more, 10 or more, 12 or more, 14 or more, 15 or more, or 17 or more, and further preferably 70 or less, 65 or less, 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or 30 or less.

The polyether-modified silicone is not particularly limited as long as it has a specific HLB, and examples thereof include PEG-9 polydimethylsiloxane, PEG-10 polydimethylsiloxane, PEG-12 polydimethylsiloxane, PEG-10 methyl ether polydimethylsiloxane, PEG-11 methyl ether polydimethylsiloxane, PEG/PPG-20/20 polydimethylsiloxane, PEG/PPG-20/23 polydimethylsiloxane, and PEG-17 polydimethylsiloxane. Among them, PEG-11 methyl ether polydimethylsiloxane is preferable.

(thickener)

In general, since it is difficult to improve the emulsion stability of an oil-in-water emulsion cosmetic containing a powder, it is common to use a thickener, particularly a water-soluble thickener, to ensure the emulsion stability of such a cosmetic. However, the blending of the thickener may improve the emulsion stability, but tends to give a sticky feel.

On the other hand, the oil-in-water emulsion cosmetic of the present disclosure can improve the emulsion stability by making the average particle diameter of the oil droplets dispersed in the dispersion medium 1 μm or less, and thus the cosmetic of the present disclosure may contain substantially no thickener. That is, the thickener may be blended in a proportion of 1 mass% or less, 0.7 mass% or less, 0.5 mass% or less, 0.1 mass% or less, 0.01 mass% or less, or 0.001 mass% or less with respect to the total amount of the cosmetic, but it is advantageous not to use the thickener from the viewpoint of sticky feeling or the like.

Viscosity of cosmetics

In several embodiments, the viscosity of the oil-in-water emulsion cosmetic of the present disclosure after 1 day of production at 25 ℃ as measured using the conditions and apparatus described in the examples below may be 10,000mpa·s or less, 9,000mpa·s or less, 8,000mpa·s or less, 7,000mpa·s or less, 6,000mpa·s or less, 5,000mpa·s or less, 4,500mpa·s or less, or 4,000mpa·s or less, and may be 500mpa·s or more, 1,000mpa·s or more, 1,500mpa·s or more, 2,000mpa·s or more, 2,500mpa·s or more, or 3,000mpa·s or more. The oil-in-water emulsion cosmetic of the present disclosure contains oil droplets having an average particle diameter of 1 μm or less, and is excellent in emulsion stability, and therefore can exhibit good emulsifying performance even at such a viscosity. Further, the cosmetic of the present disclosure exhibiting such viscosity can exhibit water-wet and light usability as a cosmetic liquid.

Method for preparing oil-in-water type emulsified cosmetic

The method for preparing the oil-in-water emulsion cosmetic of the present disclosure is not particularly limited, and the cosmetic may be prepared by a known method such as a dispersion method or an aggregation method.

The dispersion method is a method of refining a block of a dispersed phase by mechanical force. Specifically, the method of emulsifying by using the crushing force of an emulsifying machine includes, for example, a high-pressure emulsifying method in which a high-pressure homogenizer is used and a high shear force is added.

The coagulation method is a method of changing a uniformly mixed state into a supersaturated state by some means by a colloid modulation method using surface chemical properties, and causing a substance to be a dispersed phase to appear. As specific methods, an HLB temperature emulsification method, a phase inversion emulsification method, a nonaqueous emulsification method, a D-phase emulsification method, a liquid crystal emulsification method, and the like are known. Among them, a nonaqueous emulsification method (also sometimes referred to as "fine emulsification method") using a hydrophilic solvent such as a polyol in the presence of a small amount of water (or in the absence of water) is preferable.

Formulation of oil-in-water emulsion cosmetic

The formulation of the oil-in-water emulsion cosmetic of the present disclosure is not particularly limited, and examples thereof include liquid, emulsion, cream, gel, spray, and filament. Here, the term "spray" in the present disclosure may include aerosol-type sprays, and the like.

Use of oil-in-water type emulsified cosmetic

The oil-in-water emulsion cosmetic composition of the present disclosure can be used, for example, as a cosmetic composition to be applied by spreading to the skin or the like. Here, the cosmetic to be applied to the skin may contain a substance called a skin external agent.

The product form of the cosmetic of the present disclosure is not particularly limited, and examples thereof include facial cosmetics such as lotions, cosmetic liquids, emulsions, and masks; make-up cosmetics such as foundations, lipsticks, eye shadows, etc.; sunscreen cosmetics (sunscreens); body cosmetics; hair cosmetics such as shampoo, hair tonic, hair conditioner, shampoo, hair rinse, hair growth promoting material, etc.; ointments, and the like.

Examples

The oil-in-water emulsion cosmetic of the present disclosure will be described in further detail with reference to examples, but the cosmetic of the present disclosure is not limited to these. In the following, unless otherwise specified, the blending amount is expressed as mass%.

Examples 1 to 9 and comparative examples 1 to 4

The following tests were carried out on oil-in-water type emulsified cosmetics obtained by the formulations shown in tables 1 to 3 and the production methods shown below, and the results are shown in tables 1 to 3.

Evaluation method

(evaluation test of average particle diameter)

The average particle diameter of emulsified particles (oil droplets) in the oil-in-water emulsified cosmetic material before the powder portion was added was measured by a dynamic light scattering method using zeon. Here, the term "10 μm or more" in Table 3 means that the average particle diameter of the emulsified particles is about 10 μm around the measurement limit. It was also confirmed by visual observation using an optical microscope that the emulsified particles of comparative examples 3 and 4 had a particle diameter of about 10 μm.

(Rolling stability test: emulsion stability)

The prepared cosmetic was put into a 50mL transparent sample tube (diameter: 3 cm), and the sample tube was rotated at 45rpm under an atmosphere at 25℃for 4 hours, and the aggregation state of the particles was visually observed, and evaluated on the basis of the following. Here, the A-B evaluation may be regarded as acceptable, and the C-D evaluation may be regarded as unacceptable.

A: no color fringe pattern was observed with the aggregates of particles.

B: the color fringe pattern accompanying the aggregates of particles was observed very slightly.

C: the color fringe pattern accompanying the aggregates of particles was slightly observed.

D: the color fringe pattern accompanying the aggregates of particles was clearly observed.

(evaluation test for lightening)

The prepared cosmetic was applied to the wrist to dry the water, and the applied surface of the cosmetic was visually observed, and the state of lightening was evaluated on the basis of the following criteria. Here, the A-B evaluation may be regarded as acceptable, and the C-D evaluation may be regarded as unacceptable. In addition to the lightening effect, the lightening test can indirectly evaluate whether or not particles such as pigment-grade hydrophobized particles are uniformly applied to the skin surface. That is, it can be said that the pigment-grade hydrophobizing particles and the like are uniformly applied to the skin surface in the order of D, C, B, A.

A: the brightness was not uneven, and an excellent lightening effect was exhibited.

B: although brightness is extremely slightly uneven, a good lightening effect is obtained.

C: the brightness was slightly uneven, and a good lightening effect was not obtained.

D: the brightness is obviously uneven, and a good brightness improving effect is not obtained.

(evaluation test of particle dispersibility)

The prepared cosmetic was placed in a 50mL transparent sample tube (diameter: 3 cm), and the dispersion state of the particles after storage at 25℃for 7 days was visually observed, and evaluated on the basis of the following criteria.

A: no precipitate of pigment-grade hydrophobicized particles was confirmed.

B: the precipitate of the pigment-grade hydrophobicized particles was confirmed very slightly.

C: the precipitate of the pigment-grade hydrophobized particles was slightly confirmed.

D: the precipitate of the pigment-grade hydrophobized particles was clearly confirmed.

(evaluation test of usability)

The usability (tackiness) of each cosmetic when directly applied to the face was comprehensively evaluated by 3 professionals on the following evaluation criteria.

A: it is not sticky.

B: hardly felt sticky.

C: slightly tacky.

D: and feel tacky.

(evaluation test of viscosity)

The viscosity after 1 day of cosmetic preparation was evaluated by using a type B viscometer (TVB type viscometer TVB-10, manufactured by DONGMAINTERIALS Co., ltd.) under the conditions of rotor No. 3, 25℃and 12 rpm. The cosmetic of comparative example 2 was separated, and thus the viscosity was not measured.

Cosmetic preparation method

An oil-in-water emulsion cosmetic was produced by the following method using the formulations shown in tables 1 to 3. Here, the numbers shown below are identical to the numbers on the left side of the prescription of tables 1 to 3 indicating the component names.

Example 1

The materials of nos. 2 to 13 were added to a part of the ion-exchanged water of No.1 and uniformly mixed to obtain an aqueous phase portion.

The materials of nos. 24 to 27 were uniformly mixed to obtain an oil phase portion.

The materials of nos. 14, 15, 17, and 18 were uniformly mixed in the remaining ion-exchanged water of No.1 to obtain powder fractions.

After slowly adding the oil phase portion to the water phase portion, the powder portion was slowly added and uniformly dispersed by a homomixer, to obtain an oil-in-water emulsion cosmetic of example 1.

Examples 2 to 9 and comparative examples 1 to 2

Oil-in-water emulsion cosmetics of examples 2 to 9 and comparative examples 1 to 2 were obtained in the same manner as in example 1 except that the formulations shown in tables 1 to 3 were changed.

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. In addition, the cosmetic of comparative example 3 was allowed to function as an active agent by using a (acrylate/alkyl (C10-30) acrylate) crosslinked polymer having emulsifying ability as well.

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 amount of the (dimethylacrylamide/Na acryloyldimethyltaurate) crosslinked polymer of the water-soluble thickener and succinoglycan was changed.

TABLE 1

TABLE 2

TABLE 3 Table 3

Results

From the results of tables 1 and 2, it was confirmed that the oil-in-water emulsion cosmetics of examples 1 to 9, which contain oil droplets having an average particle diameter of 1 μm or less and pigment-grade hydrophobicized particles in a dispersion medium, were excellent in emulsion stability and lightening property. Furthermore, the cosmetic compositions of examples 1 to 4 and examples 7 to 9 were free from stickiness, and exhibited water-wet and light usability as a cosmetic liquid. The cosmetics of examples 5 and 6 were slightly tacky, but it is considered that the cause was that the blending amount of polyether-modified silicone or glycerin was increased as compared with other examples.

The rolling stability test of the cosmetic of comparative example 1 using untreated particles although the size corresponds to the pigment-grade hydrophobicized particles was evaluated as B. This is considered to be because the hydrophilic portion of the surfactant covers the periphery of the oil droplets, and thus untreated and hydrophilic particles tend to adhere to the oil droplets as compared with pigment-level hydrophobicized particles. Further, it is considered that hydrophilic particles are less likely to remain on the surface of the lipophilic skin and easily fall off from the surface of the skin than pigment-grade hydrophobized particles, and thus a good lightening effect cannot be obtained.

From the results of comparative examples 3 and 4, it is found that, when the particle size of oil droplets is large, the emulsion stability is improved to some extent but at a defective level by increasing the viscosity of the cosmetic, and further, improvement in the lightening property is not observed.

Prescription examples of oil-in-water emulsion cosmetics

Table 4 below shows a formulation example of the oil-in-water emulsion cosmetic of the present disclosure, but is not limited to this example. The preparation was performed in the same manner as in example 1 above, except that the respective cosmetics were changed to the formulations shown in table 4. The lotion described in the following formulation examples was excellent in emulsion stability and lightening property.

Wheat 4

Description of symbols

10. 20 pigment grade hydrophobicized particles

12. 22 oil drops

14. 24 water

30. 40 pigment grade hydrophobicized particles

32. 42 oil content

34. 44 water

Claims

1. An oil-in-water emulsified cosmetic comprising:

Oil droplets dispersed in the dispersion medium,

the dispersion medium comprises pigment-grade hydrophobicized particles,

the average particle diameter of the oil droplets is 1 μm or less.

2. The cosmetic according to claim 1, the oil droplets comprising a polyoxyethylene/polyoxyalkylene alkyl ether block polymer as a nonionic surfactant.

3. The cosmetic according to claim 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 … type 1

In the formula (1) of the present invention,

R ¹ is a hydrocarbon group having 16 to 18 carbon atoms,

PO is an oxypropylene group and the oxygen is propylene,

EO is an oxyethylene group and the oxygen content of the EO,

the PO and EO are added in a block-like manner,

m and n refer to average addition mole numbers of PO and EO, respectively, and satisfy the relationships of 70 > m > 4, 70 > n > 10, and n > m,

R ² O-(AO) _p -(EO) _q -R ³ … type 2

In the formula (2) of the present invention,

AO is an oxyalkylene group having 3 to 4 carbon atoms,

EO is an oxyethylene group and the oxygen content of the EO,

the AO and EO are added in a block-like manner,

4. The cosmetic according to any one of claims 1 to 3, wherein the dispersion medium comprises a polyether-modified silicone having an HLB of 10.0 to 18.0.

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

6. The cosmetic according to any one of claims 1 to 5, which comprises an ultraviolet absorber.

7. The cosmetic according to any one of claims 1 to 6, wherein the pigment-grade hydrophobized particles have an average particle diameter of 250nm or more.

8. The cosmetic according to any one of claims 1 to 7, which has a viscosity of 10,000 mpa-s or less.