JP4536433B2 - Polymer emulsion for cosmetics - Google Patents

Description

  The present invention relates to a polymer emulsion for cosmetics that can provide excellent blending stability to cosmetics, excellent cosmetic applicability, and high cosmetic sustainability, and cosmetics containing the same.

  Polymer emulsions are used in the fields of paint, papermaking, printing, cosmetics, etc., and physical properties (film forming temperature, film hardness, drying time, coating properties, etc.) are controlled according to the application.

  Polymer emulsions can be broadly classified into emulsions obtained using a surfactant and emulsions obtained without using a surfactant (soap-free polymer emulsion). There are various definitions of soap-free polymer emulsions. In this specification, “soap-free polymer emulsions” are surfactants, polymer type emulsifiers (nonionic, anionic, cationic), reactive surfactants. It refers to a polymer emulsion that does not contain an emulsifier.

  When a polymer emulsion using a large amount of a surfactant is added to cosmetics, twisting (eraser-like agglomerates generated during application) is generated and the cosmetic applicability is deteriorated. In addition, polymer type emulsifiers such as polyvinyl alcohol, polyvinyl pyrrolidone, and sugar derivatives have restrictions on blending such as deterioration in cosmetic applicability. Reactive surfactants are limited in cost.

  Patent Document 1 discloses a makeup cosmetic with improved water resistance by blending a non-emulsifier polymerized resin emulsion that does not use an emulsifier during polymerization. However, the blending stability, applicability, makeup sustainability, etc. were not fully satisfactory.

  Furthermore, alkyl acrylate copolymer emulsions (such as Yodosol manufactured by Nippon SC Co., Ltd.), which have been used as conventional emulsions for cosmetics, were good in terms of film properties, but in the presence of ethanol when blended with cosmetics. Then, aggregation and sedimentation of the emulsion occur, and when the “alkyl acrylate copolymer emulsion (2)” described in the blending ingredient standard for each cosmetic type is synthesized using a surfactant (Emal 20C manufactured by Kao Corporation) Rotation occurred during application.

Therefore, there has never been an inexpensive cosmetic polymer emulsion that forms a flexible film, has excellent blending stability (ethanol resistance), and does not cause twisting during application.
JP 54-49338 A

  An object of the present invention is an inexpensive polymer emulsion that forms a flexible film, and is a polymer emulsion for cosmetics that is excellent in blending stability (ethanol resistance) and coating properties (dripping resistance), and a cosmetic blended with the same. Is to provide.

This invention contains the following (A) component and (B) component, and the weight ratio of (A) component and (B) component is (A) / (B) = 80 / 20-99.9 / 0. A soap-free polymer emulsion for cosmetics comprising a polymer obtained by copolymerizing the monomer component 1 and having a glass transition temperature (Tg) of 5 to -50 ° C., and a cosmetic containing the polymer emulsion I will provide a.
(A): at least one hydrophobic monomer represented by formula (I)

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is a linear or branched alkyl group having 1 to 6 carbon atoms, or —CH ₂ OR ³ (R ³ is a straight chain having 4 to 6 carbon atoms or A group represented by (branched alkyl group), X represents —O— or —NH—. ]
(B): at least one hydrophilic monomer represented by the general formula (II), (III) or (IV)

[Wherein R ¹ represents the above-mentioned meaning, and M represents a hydrogen atom or a cation. ]

[Wherein R ¹ and X have the above-mentioned meanings. R ⁴ represents — (CH ₂ ) _n OH (n represents a number of 1 to 4), —CH ₂ OCH ₃ , —R ⁵ SO ₃ M (R ⁵ represents a linear or branched chain having 1 to ⁵ carbon atoms. An alkylene group, M is as defined above, -R ⁶ N (R ⁷ ) (R ⁸ ) (R ⁶ is a linear or branched alkylene group having 1 to 4 carbon atoms, R ⁷ and R ⁸ are each A linear or branched alkyl group having 1 to 3 carbon atoms), or —R ⁶ N ⁺ (R ⁷ ) (R ⁸ ) (R ⁹ ) · Y ⁻ (where R ⁶ , R ⁷ and R ⁸ are R ⁹ represents a group represented by a linear or branched alkyl group having 1 to 3 carbon atoms, and Y ⁻ represents an anion. ]

[Wherein M represents the above-mentioned meaning. ]

  The polymer emulsion of the present invention can be blended in cosmetics for skin and hair, and exhibits excellent blending stability (ethanol resistance), coating properties, film-forming properties, coating film stability, water resistance, etc. It does not flow or take off due to sweat or sebum, can prevent makeup collapse, and can prevent the occurrence of twisting during application.

[Monomer component]
The monomer component which comprises the polymer of this invention contains the said (A) component and (B) component.

The hydrophobic monomer of the component (A) is represented by the above general formula (I). In the general formula (I), R ² is a linear or branched chain having 1 to 6 carbon atoms and further 1 to 4 carbon atoms. An alkyl group is preferable, and X is preferably -O-.

Examples of the hydrophobic monomer (A) include (meth) acrylic acid alkyl esters having 1 to 6 carbon atoms in the alkyl group, N-alkyl (meth) acrylamides having 1 to 6 carbon atoms in the alkyl group, and the like ( (Meth) acrylic having 1 to 6 carbon atoms of alkyl group such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate Alkyl ester is preferable, and (meth) acrylic having 1 to 4 carbon atoms of alkyl group such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, etc. Acid alkyl esters are more preferred. These (A) components can be used alone or in combination of two or more, and it is particularly preferred to use a mixture of methyl (meth) acrylate and n-butyl (meth) acrylate.
In the present specification, “(meth) acryl” is a concept including both acrylic and methacrylic.

  The hydrophilic monomer as the component (B) is represented by the above general formula (II), (III) or (IV), and in the general formula (II), (III) or (IV), a cation represented by M Examples thereof include cations such as alkali metal, ammonium, alkyl or alkenylamine having 1 to 22 carbon atoms, alkanolamine having 1 to 22 carbon atoms, and basic amino acids, and alkali metal ions such as lithium, sodium and potassium. Are preferable, and potassium ion or sodium ion is particularly preferable.

In the general formula (III), the -R ⁵ SO ₃ M of the groups indicated by R ^4, R ⁵ is _{-C (CH 3) 2 CH 2} - group represented by are preferred, -R ⁶ N (R ⁷ ) (R ⁸ ) is preferably — (CH ₂ ) _m N (CH ₃ ) ₂ (m is a number from 1 to 4), and —R ⁶ N ⁺ (R ⁷ ) (R ⁸ ) ( As R ⁹ ) · Y ⁻ , — (CH ₂ ) _m N ⁺ (CH ₃ ) ₂ (R ¹⁰ ) · Y ⁻ (m is a number of 1 to 4, and R ¹⁰ is a methyl group or an ethyl group) is preferable. Examples of the anion represented by Y ⁻ include halogen ions such as Cl ⁻ and Br ⁻ and alkyl sulfate ions such as R ¹¹ SO ₄ ⁻ (R ¹¹ is a methyl group or an ethyl group).

  Among the monomers of the component (B), (meth) acrylic acid or a salt thereof and a compound represented by the general formula (III-1) are preferable, and (meth) acrylic acid or a salt thereof is more preferable.

[Wherein R ¹ and X represent the above-mentioned meanings, and R ^4-1 represents —R ⁵ SO ₃ M or —R ⁶ N ⁺ (R ⁷ ) (R ⁸ ) (R ⁹ ) · Y ⁻ (R ⁵ , M, R ⁶ , R ⁷ , R ⁸ , R ⁹ and Y ⁻ represent the aforementioned meanings). ]
The ratio of the component (A) to the component (B) in the monomer component is (A) / (B) = 80/20 to 99.9 / 0.1 by weight ratio, and 80/20 to 99/1. Is preferable, and 85/15 to 99/1 is more preferable. When the weight ratio of (A) / (B) is less than 80/20, the solubility of the polymer in water increases, making it difficult to form a stable emulsion. Further, when the weight ratio of (A) / (B) is larger than 99.9 / 0.1, twisting is likely to occur.

  The monomer component of this invention can contain the other monomer copolymerizable with these monomers other than the said (A) component and (B) component. Examples of other monomers include (meth) acrylonitrile, vinyl acetate, vinyl pyrrolidone and the like.

[Polymer emulsion]
The method for producing the polymer emulsion of the present invention is not particularly limited as long as a soap-free polymer emulsion can be obtained. The monomer component as described above is mixed with a surfactant, a polymer emulsifier, in the presence of a polymerization initiator, A method of emulsion polymerization without using an emulsifier such as a reactive surfactant is preferred. In the case of emulsion polymerization, the main component of the solvent used is water, and in some cases, a hydrophilic solvent such as a lower alcohol may be mixed. The reaction temperature is set below the boiling point of the solvent. The monomer concentration in the reaction system is not particularly limited, but is preferably 1 to 60% by weight from the viewpoint of production efficiency and aggregation suppression.

  The amount of the polymerization initiator is not particularly limited, but is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the monomer from the viewpoint of economy and reduction of the residual monomer amount. The monomer (or monomer solution) may be polymerized after being previously mixed in a solvent containing water as a main component, or may be polymerized while dropping. Similarly, the polymerization initiator (or polymerization initiator solution) may be mixed in advance in a solvent containing water as a main component, or may be dropped.

  The polymerization initiator used in the present invention is not particularly limited. For example, hydroperoxides such as hydrogen peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide, benzoyl peroxide, lauroyl peroxide. Peroxides such as oxide, and 2,2′-azobis {2-methyl-N- [2- (1-hydroxybutyl) propionamide]}, 2,2′-azobis [(2-methylpropionamidine) di Hydrochloride], 2,2′-azobis [N- (2-carboxyethyl) -2-methyl-propiondiamine] tetrahydrate, 2,2′-azobis (2,4-dimethylvaleronitrile), azobisiso Organic polymerization initiators such as azo compounds such as butyronitrile And potassium persulfate, sodium persulfate, and the like inorganic polymerization initiators such as persulfates such as ammonium persulfate. A so-called redox polymerization initiator using a reducing agent such as sodium bisulfite, ascorbic acid or a salt thereof in combination with a polymerization initiator can also be used.

  Further, a polymerization chain transfer agent may be further added during the polymerization. Specific examples of the polymerization chain transfer agent used include, for example, mercaptans such as octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, t-tetradecyl mercaptan; Xanthogen disulfides such as dimethylxanthogen disulfide, diethylxanthogen disulfide, diisopropylxanthogen disulfide; thiuram disulfides such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide; halogenated hydrocarbons such as carbon tetrachloride and ethylene bromide Hydrocarbons such as pentaphenylethane; and acrolein, methacrolein, allyl alcohol, 2-ethylhexyl Glycolate, terbinolene, α-terpinene, γ-terpinene, dipentene, α-methylstyrene dimer (2,4-diphenyl-4-methyl-1-pentene is preferably 50% by weight or more), and 9,10- Examples thereof include unsaturated cyclic hydrocarbon compounds such as dihydroanthracene, 1,4-dihydronaphthalene, indene and 1,4-cyclohexadiene; unsaturated heterocyclic compounds such as xanthene and 2,5-dihydrofuran. These may be used alone or in combination of two or more.

The glass transition temperature (Tg) of the polymer constituting the polymer emulsion of the present invention is 5 to -50 ° C, preferably -5 to -50 ° C, more preferably -10 to -50 ° C, and -20 to -50. ° C is particularly preferred. When Tg is higher than 5 ° C, it is difficult to form a film having sufficient adhesion because the polymer is hard, and when Tg is lower than -50 ° C, twisting is likely to occur, and the feeling of use is improved. descend.
In the present specification, Tg is a value measured by the following measuring method.

<Tg measurement method>
The Tg of the film after drying the polymer emulsion under reduced pressure is measured using a differential scanning calorimeter (DSC) under the following measurement conditions.

Using a DSC6200 (software EXSTAR6000 thermal analysis rheology system) manufactured by Seiko Instruments Inc., the temperature program consists of the following four stages, and Tg was determined from the Tg curve obtained in the third stage.
・ First stage: temperature rise at 20 ° C. → 20 ° C./min→hold at 100 ° C. for 1 minute ・ Second stage: temperature drop at 100 ° C. → 200 ° C./min→hold at −120 ° C. for 10 minutes ・ third stage: − 120 ° C. → Temperature rise at 10 ° C./min→Hold at 100 ° C. for 1 minute. Fourth stage: 100 ° C. → Temperature drop at 20 ° C./min→Hold at 20 ° C. for 2 minutes.

The average particle size of the polymer in the polymer emulsion of the present invention is preferably 0.01 to 1.5 μm, and more preferably 0.2 to 1.0 μm.
Here, the average particle diameter of the polymer is a value measured by dispersing in water with a laser diffraction / scattering particle size distribution measuring device manufactured by HORIBA.

  The polymer concentration of the polymer emulsion of the present invention is preferably 0.1 to 90% by weight, and more preferably 10 to 60% by weight.

[Cosmetics]
The polymer emulsion of the present invention is particularly useful as a film-forming base for cosmetics, and one or more of the polymer emulsions of the present invention can be mixed and blended into cosmetics. When mixing 2 or more types, it is also possible to combine two or more polymers having different Tg.

  The blending amount of the polymer emulsion of the present invention in cosmetics obtains the good effects of the present invention, prevents the cosmetic from becoming high in viscosity, and achieves good formulation and applicability to skin and hair. From the viewpoint, the polymer amount in the total cosmetic is preferably 1 to 60% by weight, more preferably 3 to 20% by weight.

  In the cosmetics of the present invention, components commonly used as cosmetic ingredients other than the polymer emulsion of the present invention, such as oils, moisturizers, powders, UV absorbers, chelates, as long as the effects of the present invention are not impaired. Agents, pH adjusters, preservatives, thickeners, dyes, pigments, fragrances and the like can be appropriately blended.

  Oils include silicone oil typified by dimethylpolysiloxane, hydrocarbon oil typified by isoparaffin, squalane, ester oil typified by isopropyl myristate, fluorine oil typified by fomblin, etc. Oils that can be used in cosmetics are listed. Examples of the humectant include glycerin, 1,3-butylene glycol, sorbitol and the like. The powder is not limited to inorganic and organic substances, and any powder that can be used in cosmetics can be blended.

  The cosmetic of the present invention can be produced according to a conventional method according to each application. The cosmetics of the present invention are makeup cosmetics such as various foundations, eye shadows, eye liners, eyebrows, mascaras, nail enamels, skin cosmetics such as packs, lipsticks, cheeks, sunscreens, hair cosmetics, It can be widely applied to medicinal cosmetics.

  In the examples, “%” means “% by weight” unless otherwise specified.

Example 1
Into a reaction vessel equipped with a stirrer, a reflux tube, a dropping funnel, a thermometer, and a nitrogen introduction tube, 1318 g of ion-exchanged water was added, stirred under a nitrogen stream, and heated to 70 ° C. After the system reached 70 ° C., an aqueous solution consisting of 3.8 g of potassium persulfate and 37.8 g of ion-exchanged water was added. Meanwhile, 121.0 g of methyl methacrylate, 612.6 g of n-butyl acrylate, and 28.4 g of 80% aqueous acrylic acid solution were charged into the dropping funnel and dropped into the reaction vessel at a constant rate over 3 hours. After completion of the dropwise addition, the temperature was raised to 75 ° C., and further aging was performed for 3 hours. Subsequently, 726.6 g of ion exchange water was charged into the reaction vessel, and the temperature in the system was reduced to 40 ° C. or lower. A 30% aqueous sodium hydroxide solution (14.7 g) and ion-exchanged water (43.3 g) were added to the reaction vessel to partially neutralize the acrylic acid. Water was distilled off from the system under reduced pressure until the solid content became 53%, and then cooled, and 75.0 g of 99.5% ethanol was added. Some aggregates were removed by mesh filtration to obtain a soap-free polymer emulsion having a solid content of 50% (yield about 95%). The average particle size of the polymer in the emulsion was 0.6 μm.
The Tg of the coating film of this soap-free polymer emulsion was −27 ° C.

Example 2
Into a reaction vessel equipped with a stirrer, a reflux tube, two dropping funnels, a thermometer, and a nitrogen introduction tube, 175 g of ion-exchanged water was added, stirred under a nitrogen stream, and heated to 70 ° C. After the system reached 70 ° C., an aqueous solution consisting of 0.5 g of ammonium persulfate and 5 g of ion-exchanged water was added. On the other hand, 30 g of methyl methacrylate and 60 g of n-butyl acrylate were charged into the dropping funnel, and 10 g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and 20 g of ion-exchanged water were charged simultaneously into the remaining dropping funnel. The solution was dropped into the container at a constant rate over 3 hours. After completion of the dropwise addition, the temperature was raised to 75 ° C., and further aging was performed for 3 hours. Subsequently, 80 g of ion exchange water was charged into the reaction vessel. Water was distilled off from the system under reduced pressure until the solid content became 53%, followed by cooling and addition of 10 g of 99.5% ethanol. Some aggregates were removed by mesh filtration to obtain a soap-free polymer emulsion having a solid content of 50% (yield about 95%). The average particle size of the polymer in the emulsion was 0.7 μm.
The Tg of the coating film of this soap-free polymer emulsion was −9 ° C.

Example 3
In a reaction vessel equipped with a stirrer, a reflux tube, a dropping funnel, a thermometer, and a nitrogen introduction tube, 131.8 g of ion-exchanged water was added, stirred under a nitrogen stream, and heated to 70 ° C. After the temperature in the system reached 70 ° C., Wako Pure Chemical Co., Ltd. polymerization initiator V-50 (2,2′-azobis (2,4-dimethylvaleronitrile), manufactured by Wako Pure Chemical Industries) 0.38 g, ion-exchanged water 3 An aqueous solution consisting of .78 g was added. Meanwhile, 68.0 g of ethyl acrylate and 9.5 g of 80% aqueous solution of methacryloyloxyethyldimethylethylammonium ethyl sulfate (80% MOEDES manufactured by Nitto Riken Kogyo Co., Ltd.) were charged into the dropping funnel, and the reaction vessel was charged at a constant rate over 3 hours. It was dripped at. After completion of the dropwise addition, the temperature was raised to 75 ° C., and further aging was performed for 3 hours. Subsequently, 70 g of ion exchange water was charged into the reaction vessel. Water was distilled off from the system under reduced pressure until the solid content became 53%, and then cooled, and 7.6 g of 99.5% ethanol was added. Some aggregates were removed by mesh filtration to obtain a soap-free polymer emulsion having a solid content of 50% (yield: about 92%). The average particle size of the polymer in the emulsion was 0.6 μm.
The Tg of the coating film of this soap-free polymer emulsion was -1 ° C.

Comparative Example 1
A reaction vessel equipped with a stirrer, reflux tube, dropping funnel, thermometer and nitrogen introduction tube was charged with 2 g of Kao's surfactant Emar 20C and 175 g of ion-exchanged water, and stirred under a nitrogen stream at 70 ° C. The temperature was raised to. After the system reached 70 ° C., an aqueous solution consisting of 0.5 g of ammonium persulfate and 5 g of ion-exchanged water was added. On the other hand, 16 g of methyl methacrylate, 81 g of n-butyl acrylate and 3 g of 80% acrylic acid aqueous solution were charged into the dropping funnel and dropped into the reaction vessel at a constant rate over 3 hours. After completion of the dropwise addition, the temperature was raised to 75 ° C., and further aging was performed for 3 hours. After the temperature in the system was reduced to 40 ° C. or lower, a 30% aqueous sodium hydroxide solution was added to the reaction vessel to partially neutralize 35 mol% of acrylic acid. Water was distilled off from the system under reduced pressure until the solid content reached 50%. The average particle size of the polymer in the emulsion was 0.07 μm. The Tg of the coating film of this emulsion was -27 ° C.

Comparative Example 2
The solid content was 50 in the same manner as in Example 1 except that the addition amount of methyl methacrylate was 430.9 g, the addition amount of n-butyl acrylate was 302.4 g, and the addition amount of 80% acrylic acid aqueous solution was 28.4 g. % Soap-free polymer emulsion was obtained (yield about 95%). The average particle size of the polymer in the emulsion was 0.5 μm.
The Tg of the coating film of this soap-free polymer emulsion was 20 ° C.

Comparative Example 3
A soap-free polymer having a solid content of 50% in the same manner as in Example 1 except that the addition amount of n-butyl acrylate was 733.3 g, the addition amount of 80% acrylic acid aqueous solution was 28.4 g, and methyl methacrylate was not added. An emulsion was obtained (yield about 95%). The average particle size of the polymer in the emulsion was 0.6 μm.
The Tg of the coating film of this soap-free polymer emulsion was −51 ° C.

  About the polymer emulsion obtained in Examples 1-3 and Comparative Examples 1-3, the dripping resistance and ethanol resistance were evaluated by the following method. The results are shown in Table 1.

<Angle resistance>
The polymer emulsion is placed on the back of the hand and rubbed to make a visual judgment. "Good" if no eraser-like residue is generated, "Poor" if it
<Ethanol resistance>
1 part by weight of ion-exchanged water and 1 part by weight of ethanol are mixed with 1 part by weight of the solid content of the polymer emulsion and visually judged. "Good" if no agglomerates precipitate, "Bad" if precipitated.

Formulation Examples 1-3 and Comparative Formulation Example 1
Using the polymer emulsions obtained in Examples 1 to 3 and Comparative Example 1, cosmetic ingredients were prepared by mixing the following components. The polymer solid content in the cosmetic was 11% by weight. About the obtained cosmetics, the applicability | paintability, the discomfort of the face, and the fixing property were evaluated by the following method. The results are shown in Table 2.

<Cosmetic composition>
5% by weight of a particle slurry having a solid content of 60% 2 parts by weight of a polymer emulsion having a solid content of 50% (Examples 1 to 3 or Comparative Example 1) 2 parts by weight of a hydrogel having a solid content of 1% (Pois 310 manufactured by Kao Corporation) The particle slurry having a solid content of 60% is synthesized by the following method.

  In a beaker, 2100 g of water and 300 g of 5% polyvinyl alcohol (EG-30, manufactured by Nihon Gosei Co., Ltd.) aqueous solution were added and mixed. In another beaker, 450 g (1.240 mol) of stearyl methacrylate, 50 g (1.404 mol) of butyl acrylate, 6 g of ethylene glycol dimethacrylate, and 12 g of lauroyl peroxide were added and stirred. After dissolving the lauroyl peroxide, it was mixed with the aforementioned aqueous polyvinyl alcohol solution and emulsified with a line mixer (emulsified particle size 13 μm). The emulsion was put into a 3 L reaction vessel, and dissolved oxygen was removed with nitrogen gas, and then the emulsion was heated to 70 ° C. and polymerization was continued for 6 hours. After cooling, stationary separation and decantation were performed to obtain a particle slurry having a solid content of 60% (yield 97%).

<Evaluation method>
・ Applicability: Cosmetics are applied to the face and visually judged. "Good" if no eraser-like residue comes out, "Poor" if it comes out
・ Facial discomfort: Apply cosmetics to the face and dry to evaluate the feeling of tightness on the face. "Good" if there is no sense of tension, "Bad" if there is
・ Fixability: Cosmetics are applied to the face, dried and the facial expression is changed. "Good" if the dry film does not peel off the face, "Poor" if it peels off

Claims (3)

Monomer comprising the following component (A) and component (B), wherein the weight ratio of component (A) to component (B) is (A) / (B) = 80/20 to 99.9 / 0.1 A cosmetic for skin containing a soap-free polymer emulsion containing a polymer obtained by copolymerizing components and having a glass transition temperature (Tg) of 5 to -50 ° C.
(A): at least one selected from (meth) acrylic acid alkyl esters having 1 to 6 carbon atoms in the alkyl group (B): at least one selected from compounds represented by formula (III-1)

[Wherein, R ¹ is a hydrogen atom or a methyl group, X is —O— or —NH—, R ^4-1 is —R ⁵ SO ₃ M (R ⁵ is a linear or branched chain having 1 to ⁵ carbon atoms. An alkylene group, M represents a hydrogen atom or a cation), or —R ⁶ N ⁺ (R ⁷ ) (R ⁸ ) (R ⁹ ) · Y ⁻ (R ⁶ is a linear or branched alkylene having 1 to 4 carbon atoms; Group, R ⁷ , R ⁸ and R ⁹ are each a linear or branched alkyl group having 1 to 3 carbon atoms, and Y ⁻ represents an anion). ] Average particle diameter of 0.01~1.5μm claim 1 Symbol placement of a skin cosmetic of the polymer. The skin cosmetic according to claim 1 or 2 , wherein the polymer emulsion is a film-forming agent.