Aqueous polymer emulsion for cosmetics, method for producing same, and cosmetics

Abstract

An aqueous polymer emulsion for cosmetics, which contains resin particles that contain a structural unit derived from (A) a monomer (ethyl (meth) acrylate or the like) and a structural unit derived from (C) a monomer (unsaturated carboxylic acid or the like), optionally containing a structural unit derived from (B) a monomer (unsaturated monomer having a methyl ester group), the content of the monomer unit (A) is 70-99.9% by mass, the content of the monomer unit (B) is 0-10% by mass, and the content of the monomer unit (C) is 0.1-10% by mass with respect to the total of the monomer units of the resin particles, the content of a nonionic surfactant having an HLB of 10.0-17.0 is 0.1-10 parts by mass with respect to the total of 100 parts by mass of the monomers constituting the resin particles, and the concentration of an alcohol derived from an alkyl group of the monomers is 150 ppm or less.

Description

Technical Field

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority based on Japanese Patent Application No. 2022-172406 filed on October 27, 2022, the entirety of which is incorporated herein by reference.

[0002] The present invention relates to an aqueous polymer emulsion for cosmetics, a method for producing the same, and cosmetics. Background Art

[0003] In cosmetics such as beauty cosmetics, nail cosmetics, skin care cosmetics, and hair cosmetics, water-soluble polymers are mainly used as film-forming agents in consideration of environmental and hygienic aspects. However, water-soluble polymers have poor moisture resistance and water resistance, so aqueous polymer emulsions have been widely used as film-forming agents in recent years.

[0004] From the perspective of the usability of cosmetics, cosmetics with good long-lasting properties are also desired in order to protect against daily ultraviolet rays. In particular, in hot and humid summer and during exercise, cosmetics with better water resistance, oil resistance (sebum resistance) and durability of makeup effects (hereinafter also referred to as "makeup durability") are desired. However, the film formed by the aqueous polymer emulsion used in the past is easily damaged and peeled off when wetted with water, and the water resistance cannot be said to be sufficient. In addition, due to sebum, sweat, and other oily components of cosmetics, it is twisted or flowed, causing the problem of makeup coming off, so the oil resistance cannot be said to be sufficient.

[0005] As a method for improving these disadvantages, for example, it has been proposed to prepare an aqueous polymer emulsion containing at least partially cross-linked solid and elastomeric polyorganosiloxane particles and film-forming particles (see Patent Document 1).

[0006] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2000-355532 Summary of the invention Problems to be solved by the invention However, the aqueous polymer emulsion of Patent Document 1 cannot fully exert its original film-forming ability because both the polyorganosiloxane particles and the film-forming particles are present in the aqueous system in particulate form. Although the water resistance is relatively good, the oil resistance is still insufficient.

[0007] In addition, conventional aqueous polymer emulsions generally contain trace amounts of volatile organic compounds such as unreacted monomers and decomposition products generated during polymerization. Therefore, there are problems such as the need to mask the peculiar odor of volatile organic compounds by applying base makeup, foundation, cream, etc. to the skin, making it difficult to produce fragrance-free cosmetics, and limiting their use in topical makeup such as blush, mascara, and eye shadow.

[0008] In order to reduce the volatile organic compounds in the aqueous polymer emulsion, attempts have been made to volatilize the volatile organic compounds by heating the aqueous polymer emulsion obtained by emulsion polymerization, etc., to achieve low odorization of the aqueous polymer emulsion. However, the present inventors have conducted research and found that even in the case of the above-mentioned heating treatment for low odorization, alcohol is generated in the aqueous polymer emulsion over time. From the viewpoint of achieving low odorization and improving storage stability, it is desired to develop an aqueous polymer emulsion in which the concentration of volatile organic compounds is kept low for a long time.

[0009] The present invention has been made in view of the above circumstances, and its main object is to provide an aqueous polymer emulsion for cosmetics and a cosmetic containing the aqueous polymer emulsion, which can keep the concentration of volatile organic compounds low for a long period of time and can form a film with excellent water resistance and oil resistance.

[0010] Technical solutions to solve problems The present inventors have conducted intensive studies to solve the above problems and have found that a specific structure of a monomer unit present on the surface and / or near the surface of resin particles is slowly hydrolyzed, thereby generating volatile organic compounds in the emulsion over time. According to the present invention, the following solutions are provided.

[0011] [1] A cosmetic aqueous polymer emulsion comprising resin particles, the resin particles comprising a structural unit derived from the following (A) monomer and a structural unit derived from the following (C) monomer, and optionally comprising a structural unit derived from the following (B) monomer, wherein the structural unit derived from the following (A) monomer accounts for 70 to 99.9% by mass, the structural unit derived from the following (B) monomer accounts for 0 to 10% by mass, and the structural unit derived from the following (C) monomer accounts for 0.1 to 10% by mass, relative to 100 parts by mass of the total of the structural units derived from the monomers constituting the resin particles, and the resin particles further comprise 0.1 to 10 parts by mass of a nonionic surfactant having an HLB of 10.0 to 17.0, relative to 100 parts by mass of the total of the monomers constituting the resin particles, and the concentration of an alcohol derived from an alkyl group possessed by the monomers constituting the resin particles is 150 ppm or less.

[0012] (A) Alkyl (meth)acrylate having an alkyl group having 2 to 12 carbon atoms (B) Unsaturated monomers having a methyl ester group (C) at least one monomer selected from unsaturated carboxylic acids and unsaturated carboxylic anhydrides [2] The aqueous polymer emulsion for cosmetics according to [1] above, wherein the glass transition temperature of the polymer constituting the resin particles is -20°C to 20°C.

[0013] [3] The aqueous polymer emulsion for cosmetic use according to [1] or [2] above, wherein the (B) monomer is methacrylic acid.

[0014] [4] The aqueous polymer emulsion for cosmetics according to any one of [1] to [3] above, wherein the (B) monomer is methyl (meth)acrylate.

[0015] [5] A method for producing an aqueous polymer emulsion for cosmetics, which is a method for producing the aqueous polymer emulsion for cosmetics described in any one of [1] to [4], comprising the following steps: A step of obtaining a polymer emulsion by conducting emulsion polymerization under the following conditions: the content of the (A) monomer is 70 to 99.9% by mass, the content of the (B) monomer is 0 to 10% by mass, the content of the (C) monomer is 0.1 to 10% by mass, and the content of the (A) monomer is 70 to 99.9% by mass, relative to 100 parts by mass of the total monomers used in the polymerization, relative to 100 parts by mass of the total monomers used in the polymerization, and 0.1 to 10 parts by mass of a nonionic surfactant having an HLB of 10.0 to 17.0 is contained; A step of adding a basic compound to the polymer emulsion to neutralize to a pH range of 7.0 to 10.0, and heating to a temperature of 50° C. to 90° C.; and The step of removing volatile organic compounds from the aqueous polymer emulsion by setting the pressure in a treatment container capable of reducing pressure to a range of 12 KPa to 57 KPa, maintaining the water in the treatment container in a boiling state, and supplying pressurized steam into the treatment container.

[0016] [6] A cosmetic comprising the cosmetic aqueous polymer emulsion according to any one of [1] to [4] above.

[0017] Effects of the Invention According to the present invention, a water-based polymer emulsion for cosmetics can be obtained, which can keep the concentration of volatile organic compounds low for a long time and can form a film with excellent water resistance and oil resistance. In addition, such a water-based polymer emulsion for cosmetics of the present invention can impart excellent water resistance, oil resistance and low odor to cosmetics. DETAILED DESCRIPTION

[0018] The present invention is described in detail below. It should be noted that in this specification, "(meth)acrylic acid" refers to acrylic acid and / or methacrylic acid, and (meth)acrylate refers to acrylate and / or methacrylate. The expression "a to b" in the description of the numerical range means greater than a and less than b unless otherwise specified. For example, the description of "0 to 5 mass %" means "greater than 0 mass % and less than 5 mass %".

[0019] <Aqueous polymer emulsion for cosmetics> The cosmetic aqueous polymer emulsion of the present invention is an emulsion in which resin particles are dispersed in a solvent mainly composed of water. Among them, "water-based solvent" means that the solvent contains 70% by mass or more (upper limit 100% by mass) of water, preferably 80% by mass or more of water, more preferably 90% by mass or more, further preferably 95% by mass or more, and further preferably 99% by mass or more. Any solvent other than water used can be a hydrophilic solvent, and acetone and the like can be cited. It should be noted that "cosmetic aqueous polymer emulsion" or "aqueous polymer emulsion" is sometimes referred to as "emulsion" below.

[0020] (Monomers constituting resin particles) The emulsion of the present invention contains resin particles. The monomer constituting the resin particles (i.e., the structural unit of the polymer constituting the resin particles) may be a monomer produced from conventional fossil resource materials such as petroleum, or may be a monomer produced from biomass resources in consideration of environmental issues such as global warming (hereinafter also referred to as "biomass monomer"). Biomass monomers can be preferably used as monomers constituting the resin particles in consideration of reducing dependence on fossil resource materials.

[0021] Biomass monomers are synthesized based on biomass materials, i.e., raw materials derived from renewable organic resources. The so-called biomass materials typically refer to materials derived from biological resources (typically plants that perform photosynthesis) that can be continuously reproduced as long as there is sunlight, water and carbon dioxide. Therefore, materials derived from fossil resources that have been depleted due to use after mining (fossil resource-based materials) do not belong to the concept of biomass materials mentioned here. The proportion of carbon derived from biomass in biomass monomers and polymers obtained by polymerizing biomass monomers can be estimated based on the carbon isotope content of mass number 14 measured according to ASTM D6866.

[0022] From the perspective of environmental awareness, the higher the proportion of biomass-derived carbon contained in the resin pellets, the more preferred. When biomass monomers are used as monomers constituting the resin pellets, the proportion of biomass-derived carbon is, for example, 10% or more, preferably 20% or more, more preferably 30% or more, and the closer to 100%, the more preferred.

[0023] The resin particles include, as structural units derived from monomers constituting the resin particles, structural units derived from (A) an alkyl (meth)acrylate having an alkyl group having 2 to 12 carbon atoms (hereinafter, also referred to as “(A) monomer”), and structural units derived from (C) at least one monomer selected from the group consisting of unsaturated carboxylic acids and unsaturated carboxylic anhydrides (hereinafter, also referred to as “(C) monomer”), and may further optionally include structural units derived from (B) an unsaturated monomer having a methyl group (-C(=O)-O-CH3) (hereinafter, also referred to as “(B) monomer”).

[0024] Specific examples of the (A) monomer include n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, and lauryl (meth)acrylate, and one or more thereof can be used. As the (A) monomer, an alkyl (meth)acrylate having an alkyl group having 4 to 8 carbon atoms is preferred from the viewpoint of improving the water resistance and oil resistance of the obtained emulsion, and at least one selected from n-butyl (meth)acrylate and 2-ethylhexyl acrylate is preferred from the viewpoint of improving the water resistance and oil resistance of the emulsion at a low cost.

[0025] Since the (B) monomer has a methyl ester group, it is more easily hydrolyzed, and methanol derived from the methyl ester group is generated by hydrolysis. Examples of the (B) monomer include compounds represented by the following general formula (I).

[0026] CH2=CR 1 -CO-O-(R 2 -CO-O) n -CH3…(I) (In the general formula (I), R 1 is a hydrogen atom or a methyl group, R 2 is an alkylene group having 1 to 6 carbon atoms, and n is an integer of 0 to 2. Specific examples of the (B) monomer include methyl (meth)acrylate and methoxycarbonylethyl (meth)acrylate. Among them, methyl (meth)acrylate is preferred because it is inexpensive and can sufficiently improve the water resistance and oil resistance of the emulsion. Among them, methyl methacrylate is particularly preferred because it produces a relatively small amount of alcohol (specifically methanol) over time and can form an emulsion that can form a film with good water resistance and oil resistance.

[0027] Specific examples of the (C) monomer include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, cinnamic acid, maleic anhydride, etc., and one or more of them can be used. Among them, as the (C) monomer, acrylic acid and methacrylic acid are preferred, and methacrylic acid is more preferred, from the perspective of being able to improve the water resistance and oil resistance of the emulsion at a low cost.

[0028] With respect to 100% by mass of the total of the structural units derived from the monomers constituting the resin particles, the proportion of the structural units derived from the (A) monomer (hereinafter, also referred to as “the (A) monomer units”) is 70 to 99.9% by mass, the proportion of the structural units derived from the (C) monomer (hereinafter, also referred to as “the (C) monomer units”) is 0.1 to 10% by mass, and the proportion of the structural units derived from the (B) monomer (hereinafter, also referred to as “the (B) monomer units”) is 0 to 10% by mass.

[0029] Regarding the amount of (A) monomer units, (B) monomer units, and (C) monomer units, when the (A) monomer unit is 70% by mass or more, there is a tendency to improve water resistance and makeup persistence, and when it is 99.9% by mass or less, there is a tendency to improve oil resistance and makeup persistence. When the (B) monomer unit is 10% by mass or less, there is a tendency to keep the concentration of alcohol (specifically methanol) in the emulsion low even during long-term storage, and there is a tendency to be excellent in storage stability. When the (C) monomer unit is 0.1% by mass or more, there is a tendency to improve temporal stability and adhesion, and when it is 10% by mass or less, there is a tendency to improve water resistance and oil resistance.

[0030] From the above viewpoints, the ratio of the (A) monomer unit in the resin particles is preferably 75% by mass or more, more preferably 80% by mass or more, further preferably 85% by mass or more, and further preferably 90% by mass or more, relative to the total amount of the structural units derived from the monomers constituting the resin particles. The upper limit of the (A) monomer unit is preferably 99.5% by mass or less, relative to the total amount of the structural units derived from the monomers constituting the resin particles.

[0031] The ratio of the (B) monomer unit in the resin particles is preferably 0 to 7 mass %, more preferably 0 to 5 mass %, and even more preferably 0 to 3 mass % based on the total amount of the structural units derived from the monomer constituting the resin particles.

[0032] The ratio of the (C) monomer units in the resin particles is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 1% by mass or more, relative to the total amount of the structural units derived from the monomers constituting the resin particles. The upper limit of the (C) monomer units is preferably 8% by mass or less, more preferably 6% by mass or less, relative to the total amount of the structural units derived from the monomers constituting the resin particles.

[0033] The resin particles may further have a structural unit derived from a monomer different from the (A) monomer, the (B) monomer, and the (C) monomer (hereinafter, also referred to as “other monomer”).As other monomers, there can be mentioned: (meth)acrylic acid alkyl ester compounds having an alkyl group with 13 or more carbon atoms, such as stearyl (meth)acrylate, hexadecyl-eicosyl (meth)acrylate, and behenyl (meth)acrylate; free radical polymerizable compounds having a cyclic structure, such as styrene, vinyltoluene, divinyltoluene, α-methylstyrene, p-methylstyrene, chlorostyrene, vinyldibenzyl chloride, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; hydroxyl-containing vinyl compounds, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate; dimethicone (meth)acrylate, ... Amino group-containing vinyl compounds such as methylaminomethyl ester, diethylaminomethyl (meth)acrylate, 2-dimethylaminoethyl (meth)acrylate, 2-diethylaminoethyl (meth)acrylate, 2-(di-n-propylamino)ethyl (meth)acrylate, 2-dimethylaminopropyl (meth)acrylate, 2-diethylaminopropyl (meth)acrylate, 2-(di-n-propylamino)propyl (meth)acrylate, 3-dimethylaminopropyl (meth)acrylate, 3-diethylaminopropyl (meth)acrylate, 3-(di-n-propylamino)propyl (meth)acrylate; (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylate vinyl compounds containing amide groups, such as olefinamide; vinyl compounds containing sulfonic acid groups, such as methallyl sulfonic acid and vinyl sulfonic acid; vinyl compounds containing polyoxyalkylene groups, such as (meth)acrylates of alcohols having polyoxyethylene and / or polyoxypropylene groups; vinyl compounds containing alkoxy groups, such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(n-propoxy)ethyl (meth)acrylate, 2-(n-butoxy)ethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 2-(n-propoxy)propyl (meth)acrylate, and 2-(n-butoxy)propyl (meth)acrylate; cyanomethyl (meth)acrylate (meth)acrylate compounds having a cyano group such as (meth)acrylate, 1-cyanoethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, 1-cyanopropyl (meth)acrylate, 2-cyanopropyl (meth)acrylate, 3-cyanopropyl (meth)acrylate, 4-cyanobutyl (meth)acrylate, 6-cyanohexyl (meth)acrylate, 2-ethyl-6-cyanohexyl (meth)acrylate, and 8-cyanooctyl (meth)acrylate; cyanated vinyl compounds such as acrylonitrile, methacrylonitrile, and ethacrylonitrile; vinyl ether compounds such as vinyl methyl ether, vinyl ethyl ether, vinyl n-butyl ether, vinyl phenyl ether, and vinyl cyclohexyl ether; one or more of these compounds can be used.

[0034] The ratio of the structural units derived from other monomers in the resin particles is preferably 25% by mass or less, more preferably 20% by mass or less, further preferably 10% by mass or less, further preferably 5% by mass or less, and further preferably 1% by mass or less, relative to the total amount of the structural units derived from the monomers constituting the resin particles.

[0035] (Glass transition temperature) The glass transition temperature Tg of the polymer constituting the resin particles is preferably -20 to 20°C. If the glass transition temperature Tg is above -20°C, the emulsion can have moderate adhesiveness, and a good user experience can be obtained when it is made into cosmetics. In addition, if the glass transition temperature Tg is below 20°C, there is a tendency to maintain good film-forming properties. From this point of view, the glass transition temperature Tg of the polymer constituting the resin particles is more preferably above -15°C, and more preferably above -10°C. Regarding the upper limit of the glass transition temperature Tg of the polymer constituting the resin particles, it is more preferably below 15°C, and more preferably below 10°C.

[0036] It should be noted that the calculation method of the glass transition temperature Tg of the polymer is based on the following mathematical formula (1), wherein Tg represents the glass transition temperature of the polymer (unit: K), Tga, Tgb, Tgc, etc. represent the glass transition temperature of the homopolymer of each monomer a, b, c, etc. (unit: K), and Wa, Wb, Wc, etc. represent the mass fraction of each monomer a, b, c in the copolymer.

[0037] 1 / Tg=(Wa / Tga)+(Wb / Tgb)+(Wc / Tgc)+ ··· (1) (Volume average particle size) The volume average particle size of the resin particles contained in the emulsion of the present invention is preferably 70 to 200 nm. The volume average particle size of the resin particles is the average diameter of the particles weighted by volume, and is defined by the following mathematical formula (2). It should be noted that in the mathematical formula (2), V represents the volume of the particles, n represents the number of particles, and d represents the particle size.

[0038] Volume average particle size = Σ(V1×d1+V2×d2+···+Vi×di+···+Vn×dn) / Σ(V1+V2+···+Vi+···+Vn)=Σ(Vi×di) / Σ(Vi) …(2) If the volume average particle size of the resin particles is 70 nm or more, the viscosity of the emulsion is sufficiently reduced, and a high-concentration cosmetic can be produced. In addition, by making the volume average particle size of the resin particles 200 nm or less, water resistance and oil resistance become better. From this point of view, the volume average particle size of the resin particles is preferably 75 nm or more, more preferably 80 nm or more, further preferably 85 nm or more, and further preferably 90 nm or more. The upper limit of the volume average particle size of the resin particles is preferably 150 nm or less.

[0039] It should be noted that in this specification, the volume average particle size is a value measured using a particle size analyzer UPA-EX150 manufactured by Microtrac BEL. Specifically, the measurement is performed according to the following steps. First, in an environment of 25°C, water is used as the dispersion medium and zeroing is performed (background measurement). Next, a small amount of liquid obtained by diluting the cosmetic aqueous polymer emulsion with water and adjusting the solid content concentration to 10% by mass is added dropwise to the sample cell of the above-mentioned device. After the test liquid in the sample cell becomes uniform, the sample is loaded and the displayed loading index value (loading index) is confirmed. After adjusting the loading index value to the range of 1.0 to 2.0, RUN (measurement starts). The number of measurements is 3 times, and the volume average particle size is calculated from the average value. As measurement conditions, the measurement time is set to 60 seconds, the refractive index of the sample particles is set to 1.59, the dispersion medium is set to water, and the refractive index of the dispersion medium is set to 1.33. The measurement range is 0.0008 m m~6.5400 m m.

[0040] (Nonionic surfactant) The emulsion of the present invention contains 0.1 to 10 parts by mass of a nonionic surfactant having an HLB of 10.0 to 17.0 (hereinafter also referred to as a "specific nonionic surfactant") relative to a total of 100 parts by mass of the monomers constituting the resin particles. The nonionic surfactant refers to a surfactant that exhibits surface activity without dissociating into ions in an aqueous solution. HLB (Hydrophilic-Lypophilic Balance) represents the molecular weight of the hydrophilic group portion in the total molecular weight of the surfactant, and for nonionic surfactants, it is calculated by the Griffin formula.

[0041] The HLB of a mixed surfactant composed of two or more nonionic surfactants is calculated by averaging the HLB values ​​of the respective nonionic surfactants based on their blending ratios, and specifically, is calculated by the following mathematical formula (3).

[0042] HLB of mixed surfactants = Σ(HLBx×Wx) / ΣWx …(3) In the mathematical formula (3), HLBx represents the HLB value of the nonionic surfactant X, and Wx represents the mass (unit: g) of the nonionic surfactant X having the HLBx value.

[0043] From the viewpoint of sufficiently reducing the amount of alcohol generated in the emulsion due to hydrolysis during long-term storage, the HLB of the specific nonionic surfactant contained in the emulsion of the present invention is preferably 11.0 to 17.0, more preferably 12.0 to 17.0, further preferably 12.0 to 16.5, and further preferably 12.5 to 16.5.

[0044] In the emulsion of the present invention, the total amount of monomers constituting resin particles contained in the emulsion is set to 100 parts by mass, and the content of the specific nonionic surfactant is 0.1 to 10 parts by mass. If the content of the specific nonionic surfactant is less than 0.1 parts by mass, the amount of the specific nonionic surfactant is too small, so there is a tendency that the amount of alcohol generated in the emulsion due to hydrolysis during long-term storage cannot be fully reduced. In addition, if the content of the specific nonionic surfactant exceeds 10 parts by mass, there is a tendency that the water resistance and oil resistance of the film formed by using the emulsion are poor, and the use experience when making cosmetics is insufficient. From such a viewpoint, the amount of the specific nonionic surfactant contained in the emulsion of the present invention is preferably 0.5 parts by mass or more, more preferably 0.75 parts by mass or more, further preferably 1.0 parts by mass or more, further preferably 1.2 parts by mass or more, and further preferably 1.5 parts by mass or more, relative to a total of 100 parts by mass of monomers constituting resin particles. The upper limit of the content of the specific nonionic surfactant is preferably 8.0 parts by mass or less, more preferably 7.0 parts by mass or less, further preferably 6.0 parts by mass or less, and further preferably 5.5 parts by mass or less, based on 100 parts by mass of the total monomers constituting the resin particles.

[0045] (Alcohol concentration) The inventors of the present invention have conducted research and found that in an emulsion containing resin particles, the alkyl groups of the monomers constituting the resin particles are hydrolyzed over time, thereby generating alcohols in the emulsion over time. In this regard, the emulsion of the present invention fully suppresses the generation of alcohols derived from the alkyl groups of the monomers constituting the resin particles, and can keep the alcohol concentration in the emulsion low even after long-term storage. Specifically, the concentration of alcohol in the emulsion of the present invention is 150 ppm or less, preferably 120 ppm or less, more preferably 100 ppm or less, further preferably 75 ppm or less, further preferably 50 ppm or less, further preferably 30 ppm or less, further preferably 20 ppm or less, further preferably 10 ppm or less, and the closer to 0 ppm, the more preferred. That is, after long-term storage of the emulsion of the present invention, the concentration of alcohol in the emulsion is also as low as 150 ppm or less, and the storage stability is excellent.

[0046] In the present specification, “the alcohol concentration in the emulsion after long-term storage is 150 ppm or less” means that the alcohol concentration in the emulsion is 150 ppm or less when the emulsion is placed in a sealed container and left at 50° C. for 4 weeks.

[0047] Among them, as alcohols derived from the alkyl groups possessed by the monomers constituting the resin particles, alcohols derived from the alkyl groups having 2 or more carbon atoms possessed by the (A) monomer, and alcohols (methanol) derived from the methyl groups in the methyl ester groups possessed by the (B) monomer can be cited. As alcohols produced by the monomers through hydrolysis of these monomers, alcohols having 1 to 4 carbon atoms can be cited, specifically, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, and tert-butanol can be cited. Among them, the (B) monomer is particularly easy to hydrolyze to produce methanol. In addition, methanol is one of the components avoided in cosmetics, and it is desired that the methanol content in the cosmetics is sufficiently low. According to the emulsion of the present invention, the concentration of alcohols containing methanol can be suppressed to a low level even when stored for a long time, which is suitable for cosmetic uses.

[0048] (Method for producing emulsion) The emulsion of the present invention can be obtained by performing emulsion polymerization using a monomer mixture containing (A) monomer and (C) monomer and (B) monomer as an optional component to obtain an aqueous polymer emulsion containing resin particles, neutralizing the obtained aqueous polymer emulsion and performing a heat treatment, and then removing volatile organic compounds in the aqueous polymer emulsion. Specifically, the emulsion of the present invention is preferably produced by a method including the following polymerization step, neutralization / heating step, and deodorization step.

[0049] (1) Polymerization step: A step of obtaining an emulsion by emulsion polymerization under the following conditions: the content of the (A) monomer is 70 to 99.9 mass %, the content of the (B) monomer is 0 to 10 mass %, and the content of the (C) monomer is 0.1 to 10 mass % relative to 100 mass parts of the total monomers used in the polymerization; and 0.1 to 10 mass parts of a nonionic surfactant having an HLB of 10.0 to 17.0 is contained relative to 100 mass parts of the total monomers constituting the resin particles.

[0050] (2) Neutralization / heating step: a step of adding a basic compound to the emulsion obtained in the polymerization step to neutralize the emulsion to a pH range of 7.0 to 10.0, and heating the emulsion to a temperature of 50° C. to 90° C.

[0051] (3) Deodorization step: A step of removing volatile organic compounds from the emulsion after being heated in the neutralization / heating step by setting the pressure in the treatment container capable of reducing pressure to a range of 12 kPa to 57 kPa, maintaining the water in the treatment container in a boiling state, and supplying pressurized steam into the treatment container. Hereinafter, each step will be described in detail.

[0052] (1) Polymerization process The method of emulsion polymerization is not particularly limited, and for example, it can be carried out by the following reactions, etc.: an intermittent reaction in which the monomer, surfactant and water are all put into a reaction container and reacted; a dropwise reaction in which the monomer is slowly added dropwise to the reaction container during the polymerization reaction to react. Among them, the dropwise reaction is preferably used from the perspective of easily controlling the heat generated during the polymerization reaction. In addition, in order to further improve the polymerization stability, during the dropwise reaction, it is preferred that the monomer, surfactant and water are stirred and mixed to form an emulsified monomer pre-emulsion, and the monomer pre-emulsion is slowly added dropwise to the reaction container during the polymerization reaction.

[0053] The emulsion polymerization reaction is carried out in the presence of a nonionic surfactant (specific nonionic surfactant) having an HLB of 10.0 to 17.0. If the amount of the specific nonionic surfactant used in the polymerization reaction is too small, the effect of reducing the amount of alcohol generated in the emulsion due to hydrolysis during long-term storage cannot be fully obtained. In addition, if the amount of the specific nonionic surfactant used exceeds 10% by mass, there is a tendency that the water resistance and oil resistance of the obtained emulsion and the use experience when made into cosmetics are insufficient. Therefore, the amount of the specific nonionic surfactant used in the polymerization reaction is preferably 0.5 parts by mass or more, more preferably 0.75 parts by mass or more, further preferably 1.0 parts by mass or more, further preferably 1.2 parts by mass or more, and further preferably 1.5 parts by mass or more, relative to a total of 100 parts by mass of the monomers used in the polymerization. The upper limit of the amount of the specific nonionic surfactant is preferably 8.0 parts by mass or less, more preferably 7.0 parts by mass or less, further preferably 6.0 parts by mass or less, and further preferably 5.5 parts by mass or less.

[0054] It should be noted that the amount of the specific nonionic surfactant contained in the emulsion of the present invention finally obtained is 0.1 to 10 parts by mass relative to a total of 100 parts by mass of the monomers constituting the resin particles, and the specific nonionic surfactant contained in the emulsion of the present invention may not be derived from the specific nonionic surfactant used in the emulsion polymerization. That is, the specific nonionic surfactant can be put into the reaction container before the start of polymerization, or added to the reaction container after the start of polymerization (i.e., during the polymerization reaction), or added to the emulsion after the polymerization is completed. From the perspective of fully reducing the amount of alcohol produced in the emulsion due to hydrolysis during long-term storage and the perspective of productivity, it is preferred that at least a portion of the specific nonionic surfactant used in the manufacture of the emulsion of the present invention is added to the reaction container before the end of polymerization, and it is more preferred that all the specific nonionic surfactants are added to the reaction container before the end of polymerization.

[0055] The surfactant used in the polymerization reaction may be only a specific nonionic surfactant, or a surfactant different from the specific nonionic surfactant may be used in combination (hereinafter also referred to as "other surfactants"). As other surfactants, nonionic surfactants, anionic surfactants, cationic surfactants, polymerizable surfactants, etc. having an HLB of less than 10.0 or greater than 17.0 may be cited, among which anionic surfactants are preferred. Among them, anionic surfactants refer to surfactants that can become ions in aqueous solution and whose hydrophilic parts become anions. Cationic surfactants refer to surfactants that can become ions in aqueous solution and whose hydrophilic parts become cations. Polymerizable surfactants refer to anionic or nonionic surfactants having one or more unsaturated double bonds capable of free radical polymerization in the molecule.

[0056] If specific examples of the surfactant used in the emulsion polymerization for producing the emulsion of the present invention are given, examples of the nonionic surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether and polyoxyethylene behenyl ether; polyoxyethylene alkyl phenyl ethers such as polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether; polyoxyethylene styrenated phenyl ether, polyoxyethylene distyrenated phenyl ether, sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate and the like; Sorbitan higher fatty acid esters; polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan monostearate; polyoxyethylene higher fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate; glycerol higher fatty acid esters such as oleic acid monoglyceride and stearic acid monoglyceride; polyoxyethylene-polyoxypropylene block copolymers, polyoxyethylene polyoxypropylene hexadecyl ether and polyoxyethylene polyoxypropylene decyl tetradecyl ether and other polyoxyethylene polyoxypropylene alkyl ethers; coconut fatty acid diethanolamide, lauric acid diethanolamide, myristic acid Diethanolamides such as diethanolamide, palmitic acid diethanolamide, stearic acid diethanolamide, isostearic acid diethanolamide and oleic acid diethanolamide; monoethanolamides such as coconut oil fatty acid monoethanolamide, lauric acid monoethanolamide, myristic acid monoethanolamide, palmitic acid monoethanolamide, stearic acid monoethanolamide, isostearic acid monoethanolamide and oleic acid monoethanolamide; isopropanolamides such as coconut oil fatty acid isopropanolamide, lauric acid isopropanolamide, myristic acid isopropanolamide, palmitic acid isopropanolamide, stearic acid isopropanolamide, isostearic acid isopropanolamide and oleic acid isopropanolamide ; polyoxyethylene coconut oil fatty acid monoethanolamide, polyoxyethylene lauric acid monoethanolamide, polyoxyethylene myristic acid monoethanolamide, polyoxyethylene palmitic acid monoethanolamide, polyoxyethylene stearic acid monoethanolamide, polyoxyethylene isostearic acid monoethanolamide, and polyoxyethylene oleic acid monoethanolamide; alkyl glucosides such as decyl glucoside and lauryl glucoside; alkyl dimethyl amine oxides such as lauryl dimethyl amine oxide and stearyl dimethyl amine oxide; maltitol hydroxy fatty acid alkyl ether, alkylated polysaccharide, sucrose fatty acid ester, fatty acid isopropanolamide, etc. It should be noted that as the specific nonionic surfactant, a surfactant having an HLB of 10.0 to 17.0 can be appropriately selected and used from these.

[0057] Examples of the anionic surfactant include: alkyl aryl sulfonates such as laurylbenzenesulfonic acid; polyoxyethylene alkyl ether sulfates such as polyoxyethylene lauryl ether sulfate; alkyl sulfates such as lauryl sulfate; polyoxyethylene polyoxypropylene alkyl ether sulfates, polyoxyethylene lauryl ether acetates, etc.; alkyl sulfosuccinates such as dialkyl sulfosuccinates, polyoxyalkylene alkyl sulfosuccinates, and dioctyl sulfosuccinate; polyoxyethylene styrenated phenyl ether sulfates, polyoxyethylene propylene alkyl ether sulfates, polyoxyethylene lauryl ether acetates, etc. Higher fatty acid salts such as oxyethylene distyrenated phenyl ether sulfate and sodium oleate; polyoxyethylene fatty acid amide ether sulfate, salt of coconut oil fatty acid methyl taurine, N-acyl-L-aspartate, coconut oil fatty acid ethyl ester sulfonate, salt of alkyl β-alanine, acyl methyl taurine, alkyl ethane sulfonate, polyoxyethylene alkyl ether carboxylate, alkane sulfonate, olefin sulfonate, alkyl phosphate, polyoxyalkylene alkyl ether phosphate, alkyl or alkenyl phosphate, alkyl amide phosphate, etc.

[0058] Examples of the cationic surfactant include alkyltrimethylammonium salts such as lauryltrimethylammonium chloride; dialkyldimethylammonium salts such as distearyldimethylammonium chloride; alkyldimethylethylammonium salts such as octyldimethylethylammonium chloride; trialkylbenzylammonium salts such as tributylbenzylammonium chloride; alkyldimethylbenzylammonium salts such as lauryldimethylbenzylammonium chloride; alkylamine salts such as stearylamine hydrochloride; alkyldimethylaminopropylamides such as stearyldimethylaminopropylamide; alkylpyridinium salts such as laurylpyridinium chloride, etc.

[0059] Examples of the polymerizable surfactant include propylene-alkyl sulfosuccinate salts, (meth)acrylic acid polyoxyethylene sulfates, (meth)acrylic acid polyoxyethylene phosphates (e.g., manufactured by Sanyo Chemical Industries, Ltd., trade name: ELEMINOL RS-30, etc.), polyoxyethylene alkyl propylene phenyl ether sulfates [e.g., manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: AQUALON HS-10, etc.], allyloxymethyl alkoxy polyoxyethylene sulfates (e.g., manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: AQUALON KH-10, etc.), allyloxymethyl nonylphenoxyethyl hydroxy polyoxyethylene sulfates (e.g., manufactured by ADEKA, trade name: ADEKA REASOAP SE-10, etc.), allyloxymethyl alkoxyethyl hydroxy polyoxyethylene sulfates (e.g., manufactured by ADEKA, trade name: ADEKA REASOAP SR-10, SR-30, etc.), polyoxyalkylene alkenyl ether sulfates (e.g., manufactured by Kao Corporation, trade name: Latemul PD-104, PD-105), bis(polyoxyethylene polycyclic phenyl ether) methacrylate sulfate (e.g. manufactured by Nippon Emulsifier Co., Ltd., trade name: Antox MS-60, etc.), allyloxymethyl alkoxyethyl hydroxypolyoxyethylene (e.g. manufactured by ADEKA, trade name: ADEKA REASOAP ER-20, etc.), polyoxyethylene alkyl propenyl phenyl ether (e.g. manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: AQUALON RN-20, etc.), allyloxymethyl nonylphenoxyethyl hydroxypolyoxyethylene (e.g. manufactured by ADEKA, trade name: ADEKA REASOAP NE-10, etc.), etc.

[0060] During the polymerization reaction, the method for adding the surfactant is not particularly limited. From the viewpoint of fully reducing the volume average particle size of the resin particles, it is preferred that at least a portion of the surfactant used during the polymerization reaction is pre-added to the reaction vessel before the polymerization starts to carry out the polymerization reaction. At this time, the surfactant pre-added to the reaction vessel before the polymerization starts can be a specific nonionic surfactant, or other surfactants, or a mixture thereof. In addition, the addition of the surfactant can be carried out simultaneously with the addition of the monomer, or at a different time from the addition of the monomer. In addition, as required, the surfactant can also be dissolved in water, etc. and added. In the polymerization reaction, the surfactant can be added after the surfactant is initially put into the polymerization initiation. The additional addition of the surfactant can be carried out once, or more than twice, or it can be added by continuous dropwise addition.

[0061] During polymerization, the amount of surfactant used (the total amount when two or more are used) is not particularly limited, and is preferably 0.1 to 20 parts by mass relative to the total amount of monomers used in the polymerization (100 parts by mass). If a surfactant is used in an appropriate amount, the mechanical stability of the resin particles is further improved, and if a polymerizable surfactant is used in an appropriate amount, the mechanical stability is further improved. When the amount of surfactant used is 0.1 parts by mass or more, good emulsification stability can be ensured. In addition, when the amount of surfactant used is 20 parts by mass or less, it is preferred from the perspective of ensuring good water resistance. From this point of view, the amount of surfactant used is more preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, and more preferably 1.0 parts by mass or more relative to the total amount of monomers used in the polymerization. Regarding the upper limit of the amount of surfactant used, it is more preferably 17 parts by mass or less, more preferably 15 parts by mass or less, and more preferably 12 parts by mass or less relative to the total amount of monomers used in the polymerization.

[0062] In the emulsion polymerization, it is preferred to use a radical polymerization initiator (hereinafter referred to as “polymerization initiator”). As the polymerization initiator, a known oil-soluble polymerization initiator or water-soluble polymerization initiator can be used.

[0063] Examples of the oil-soluble polymerization initiator include organic peroxides such as benzoyl peroxide, tert-butyloxybenzoate, tert-butyl hydroperoxide, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, and p-menthane hydroperoxide; and azobis compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and 1,1'-azobis-cyclohexane-1-carbonitrile.

[0064] Examples of the water-soluble polymerization initiator include ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, and 2,2′-azobis(2-methylpropionamidine) dihydrochloride.

[0065] In the emulsion polymerization, a reducing agent can be used together with the polymerization initiator. By using the reducing agent together, the polymerization reaction can be promoted. Examples of such reducing agents include reducing organic compounds such as ascorbic acid, isoascorbic acid, tartaric acid, citric acid, glucose, metal salts such as formaldehyde sulfoxylate, reducing inorganic compounds such as sodium sulfite, sodium bisulfite, sodium pyrosulfite (SMBS), sodium sulfoxylate, ferrous chloride, Rongalite, thiourea dioxide, and the like.

[0066] In the emulsion polymerization, a water-soluble polymerization initiator is preferably used as the polymerization initiator. The polymerization initiator is preferably used in an amount of 0.05 to 5 parts by mass relative to 100 parts by mass of the monomer mixture. The reducing agent is preferably used in an amount of 0.01 to 2.5 parts by mass relative to 100 parts by mass of the monomer mixture.

[0067] In the emulsion polymerization for obtaining the emulsion of the present invention, a buffer, a chain transfer agent, etc. can be used as needed. Examples of the buffer include sodium acetate, sodium citrate, sodium bicarbonate, etc. Examples of the chain transfer agent include 2-mercaptoethanol, octyl mercaptan, tert-dodecyl mercaptan, lauryl mercaptan, stearyl mercaptan, 2-ethylhexyl thioglycolate, octyl thioglycolate, 2-ethylhexyl mercaptopropionate, octyl mercaptopropionate, etc.

[0068] After the polymerization is completed, the subsequent neutralization / heating step can be carried out immediately, but in order to reduce unreacted monomers, it is preferred to carry out a treatment (aging treatment) in which the polymerization temperature or a temperature near the polymerization temperature (for example, the polymerization temperature ± 10°C) is maintained for a predetermined time. The aging treatment time can be appropriately set, for example, 30 minutes to 5 hours. In addition, after the aging treatment is completed, a treatment can be appropriately carried out to reduce the temperature of the emulsion to a temperature lower than the polymerization temperature.

[0069] (2) Neutralization / heating process Examples of the alkaline compound used in the neutralization / heating step include ammonia; alkylamines such as trimethylamine, triethylamine, and butylamine; alcoholamines such as 2-dimethylaminoethanol, diethylaminoethanol, diethanolamine, triethanolamine, and aminomethylpropanol; etheramines such as morpholine; basic amino acids such as arginine; aqueous solutions of metal hydroxides such as potassium hydroxide and sodium hydroxide; and the like.

[0070] The amount of the basic compound used can be appropriately adjusted so that the pH of the emulsion after the addition of the basic compound (i.e., the pH of the emulsion during the heat treatment) is in the range of 7.0 to 10.0. From the viewpoint of sufficiently reducing the amount of alcohol generated in the emulsion due to hydrolysis during long-term storage, the pH of the emulsion after the addition of the basic compound is preferably 7.2 to 10.0, more preferably 7.5 to 10.0, and even more preferably 7.7 to 10.0.

[0071] The method for heating the emulsion to which the alkaline compound has been added is not particularly limited. For example, it can be carried out using a heating jacket, a heat exchanger disposed outside a processing container containing the emulsion, etc. In addition, when the emulsion to which the alkaline compound has been added is heated, it can be heated while appropriately stirring.

[0072] In the neutralization / heating process, the temperature of the emulsion is set to a range of 50°C to 90°C. When the emulsion to which the alkaline compound is added is heated, if the temperature of the emulsion is lower than 50°C, the hydrolysis rate of the monomers constituting the resin particles slows down, and sometimes the hydrolysis cannot be fully performed. As a result, alcohol may be generated in the emulsion over time due to the long-term storage of the emulsion, and the storage stability of the emulsion is reduced. On the other hand, if the temperature of the emulsion exceeds 90°C, a large amount of polymer film is generated on the inner wall surface of the processing container to which the emulsion is added, especially at the interface of the gas-liquid phase, and the quality may be reduced due to the decrease in the concentration of non-volatile components. From these viewpoints, the temperature of the emulsion when the emulsion to which the alkaline compound is added is preferably 50°C to 85°C, more preferably 50°C to 80°C, and further preferably 55°C to 80°C. The heating treatment can be carried out under atmospheric pressure or under reduced pressure.

[0073] The heating time of the emulsion to which the basic compound is added varies depending on the pH of the emulsion, the temperature, the type of the basic compound, etc., but is preferably within 10 hours from the viewpoint of productivity. In addition, the emulsion obtained by the above polymerization step can be maintained at a concentration of alcohol below 150 ppm after long-term storage by heating for 1 to 5 hours after the addition of the basic compound.

[0074] Among them, in the emulsion obtained by emulsion polymerization, the generated polymer is substantially all or mostly present in the emulsion in the form of resin particles, but sometimes a part of it is dissolved in the water phase and exists. Through the research of the present inventors, it is known that in addition to the (A) monomer unit constituting the polymer in the water phase in the emulsion and the (B) monomer unit optionally contained in the polymer, the (A) monomer unit and the (B) monomer unit optionally present on the surface and / or near the surface of the resin particles are gradually hydrolyzed during the long-term storage of the emulsion, thereby, in the emulsion, alcohols derived from the alkyl group possessed by the (A) monomer unit and alcohols derived from the methyl group possessed by the optionally contained (B) monomer unit are generated over time. Among them, methyl (meth)acrylate is particularly easy to hydrolyze to produce methanol.

[0075] In view of the above, in the present invention, instead of directly using the emulsion obtained by emulsion polymerization in the subsequent deodorization step to remove volatile organic compounds from the emulsion, a specific nonionic surfactant is included in the emulsion, an alkaline compound is added to the emulsion before the deodorization step to neutralize it, and a heating treatment is performed to a temperature within a predetermined range before the deodorization step is performed, thereby suppressing the generation of alcohol generated by hydrolysis during long-term storage to a low level.

[0076] The reason why the amount of alcohol generated by hydrolysis during long-term storage can be suppressed to a low level by adding a basic compound to an emulsion containing a specific nonionic surfactant for neutralization and further heating and performing a deodorization step is not limited to the present invention, but it is presumed that the specific nonionic surfactant causes the interface between the aqueous phase and the particle surface to become blurred, and hydrolysis can proceed to the (A) monomer units and the (B) monomer units as an optional component that are present near the particle surface. That is, it is believed that hydrolysis that originally proceeds slowly over a long period of time during long-term storage of the emulsion is intentionally caused to occur during the production of the emulsion in the present invention, so that the generation of alcohol over time can be suppressed during long-term storage of the emulsion obtained by the production.

[0077] It should be noted that when an aging treatment is performed after the completion of polymerization, the neutralization / heating step can also be implemented by the aging treatment. That is, an alkaline compound can be added immediately after the completion of polymerization and heated, thereby simultaneously performing aging and hydrolysis of the (A) monomer unit and the (B) monomer unit. In addition, an alkaline compound can be added to an emulsion containing a specific nonionic surfactant for neutralization, and after further heating, an alkaline compound can be further added to the emulsion for the purpose of adjusting the pH of the emulsion, etc.

[0078] (3) Deodorization process The emulsion obtained by emulsion polymerization generally contains trace amounts of volatile organic compounds such as unpolymerized monomers and decomposition products generated during polymerization. In addition, the emulsion after the neutralization / heating step contains alcohols generated by adding a basic compound to the emulsion obtained by the polymerization step and heating, and more specifically, alcohols derived from the alkyl groups of the monomers constituting the resin particles as volatile organic compounds. When the concentration of volatile organic compounds in the emulsion is high, there is a concern that it may become a cause of odor. Therefore, it is preferred that the emulsion obtained after the polymerization step and the neutralization / heating step be treated to remove the volatile organic compounds contained in the emulsion, thereby achieving low odor.

[0079] Examples of methods for reducing volatile organic compounds include: a method of removing residual volatile organic compounds by volatilizing them by heating the emulsion; a method of circulating a gas such as air in the gas phase of the emulsion; a method of blowing water vapor into the emulsion; a method of distilling volatile organic compounds under reduced pressure, etc. In order to sufficiently reduce the concentration of volatile organic compounds in the emulsion and reduce odor, it is preferred to blow pressurized water vapor into the emulsion heated in the neutralization / heating step under reduced pressure to reduce the volatile organic compounds in the emulsion to a very small amount of 150 ppm or less.

[0080] Specifically, it is preferred that the heated emulsion obtained by the neutralization / heating step is placed in a treatment container capable of reducing pressure, the pressure in the treatment container is set in the range of 12 KPa to 57 KPa, and the water in the treatment container is maintained in a boiling state, pressurized water vapor is supplied to the treatment container, and the water vapor in the gas phase in the treatment container and the volatile organic compounds vaporized from the emulsion are removed to the outside of the system by an exhaust pump, thereby removing the volatile organic compounds in the emulsion and preparing a low-odor emulsion.

[0081] The temperature of the emulsion when the water vapor is blown is preferably set to a range of 50°C to 85°C. If the temperature of the emulsion when the water vapor is blown is 50°C or higher, the removal rate of volatile organic compounds can be suppressed from being slowed down, and a low-odor emulsion can be obtained efficiently. On the other hand, by setting the temperature of the emulsion when the water vapor is blown to 85°C or lower, a large amount of polymer film can be suppressed from being generated on the inner wall surface of the processing container, especially at the interface of the gas-liquid phase, and the quality reduction caused by the reduction of the concentration of non-volatile components can be suppressed.

[0082] In order to keep the water in the treatment container in a boiling state, the pressure in the container when the pressurized steam is blown into the treatment container is preferably set to a range of 12KPa to 57KPa (90mmHg to 430mmHg when converted to "mmHg"). In view of being able to set the emulsion temperature to a lower temperature during the deodorization treatment and being able to suppress the generation of aggregates of polymer particles to a low level, the pressure in the container is preferably 12KPa (90mmHg) to 40KPa (300mmHg), and more preferably 12KPa (90mmHg) to 30KPa (225mmHg).

[0083] In order to avoid sudden boiling of the emulsion, it is preferred to stir during the blowing of the pressurized steam. In addition, since bubbles are easily generated with stirring, a defoamer may be used in an appropriate amount to suppress this. Preferred defoamers include polyether defoamers (e.g., manufactured by SAN NOPCO, trade name: SN Defoamer PC, etc.) and silicone defoamers (e.g., manufactured by Shin-Etsu Chemical, trade name: KS-66, etc.).

[0084] As pressurized water vapor, it is preferred to use water vapor with a gauge pressure of about 0.05 to 0.50 MPa (temperature 110 to 160°C), more preferably 0.05 to 0.40 MPa, and further preferably 0.10 to 0.30 MPa. The amount of pressurized water vapor supplied to the processing container is preferably set to an amount of 5 to 100 parts by mass of pressurized water vapor relative to 100 parts by mass of the emulsion, more preferably 5 to 90 parts by mass, and further preferably 5 to 80 parts by mass. By making the amount of pressurized water vapor within the above range, the heat history applied to the emulsion can be suppressed, and the instability of the emulsion can be suppressed. In addition, the removal efficiency of volatile organic compounds can be fully improved.

[0085] The time required for the steam treatment varies depending on the supply rate of the pressurized steam and other conditions, but is preferably within 10 hours from the perspective of productivity. In the emulsion of the present invention, the concentration of volatile organic compounds can be reduced to 150 ppm or less by a 3 to 6 hour steam treatment.

[0086] The nonvolatile content of the emulsion of the present invention is preferably 30 to 70% by mass, more preferably 40 to 60% by mass. The "nonvolatile content" refers to the residual mass after heating a sample at 155° C. for 30 minutes in a hot air circulation dryer, or the ratio of the residual mass to the mass of the sample before heating.

[0087] The viscosity of the emulsion of the present invention is preferably 10 to 2000 mPa·s, more preferably 10 to 500 mPa·s, and even more preferably 10 to 300 mPa·s, as measured by a B-type viscometer at 25°C and 12 rpm.

[0088] <Aqueous polymer emulsion composition for cosmetics> By adding one or more of the following components to the emulsion of the present invention, a water-based polymer emulsion composition for cosmetics can be obtained. When added to a cosmetic formula, as long as the effect of the present invention is not impaired, it can usually be used in combination with the components added to the cosmetics as needed. The water-based polymer emulsion composition for cosmetics can include, for example, known components such as thickeners, film-forming aids, plasticizers, moisturizers, ultraviolet absorbers, fatty acid soaps, greases, waxes, hydrocarbon oils, ester oils, powders, polymer compounds, preservatives, antioxidants, pH adjusters, chelating agents, and colorants.

[0089] Examples of the thickener include alkali swelling thickeners, associative polyurethanes, carboxyvinyl polymers, thickening polysaccharides, and clay minerals.

[0090] Examples of the film-forming aid and plasticizer include: cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; carbitols such as carbitol, dimethyl carbitol, diethyl carbitol, butyl carbitol, and dibutyl carbitol; carbonates such as ethylene carbonate, diethylene carbonate, and propylene carbonate; acetates such as cellosolve acetate, butyl cellosolve acetate, butyl carbitol acetate, and sucrose acetate; alcohols such as ethanol, propanol, butanol, pentanol, hexanol, benzyl alcohol, and 2-phenylethanol; glycols such as ethylene glycol, propylene glycol, butanediol, and hexanediol; esters such as phthalic acid diesters, adipate diesters, succinic acid diesters, sebacic acid diesters, and rosin acid citrate; benzoic acid esters such as sucrose benzoate, and diethylbenzene.

[0091] Examples of the moisturizer include sorbitol, xylitol, propylene glycol, dipropylene glycol, 1,3-butylene glycol, glycerin, diglycerin, polyethylene glycol, hyaluronic acid, chondroitin sulfate, pyrrolidone carboxylate, and DL-pyrrolidone carboxylate.

[0092] Examples of the ultraviolet absorber include benzophenone derivatives such as 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid sodium, dihydromethoxybenzophenone, dihydroxymethoxybenzophenone-sodium sulfonate, 2,4-dihydroxybenzophenone, and tetrahydroxybenzophenone; and para-aminobenzoic acid, ethyl para-aminobenzoate, glyceryl para-aminobenzoate, and para-dimethylbenzoate. Benzoic acid derivatives such as amyl para-aminobenzoate, and octyl para-dimethylaminobenzoate; methoxycinnamic acid derivatives such as ethyl para-methoxycinnamate, isopropyl para-methoxycinnamate, octyl para-methoxycinnamate, 2-ethoxyethyl para-methoxycinnamate, sodium para-methoxycinnamate, potassium para-methoxycinnamate, and mono-2-ethylhexanoic acid glyceryl para-methoxycinnamate; octyl salicylate, phenyl salicylate, homomenthyl salicylate Salicylate), salicylic acid derivatives such as dipropylene glycol salicylate, ethylene glycol salicylate, myristyl salicylate, and methyl salicylate; urocanic acid, ethyl urocanate, ethyl urocanate, 4-tert-butyl-4'-methoxybenzoylmethane, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-phenyl-5-methylbenzoxazole, methyl anthranilate, and 2-ethylhexyl dimethoxybenzylidene dioxoimidazolidine propionate.

[0093] As fatty acid soap, for example, alkali salts of higher fatty acids of C6 to 24 can be exemplified. The fatty acid may be saturated or unsaturated, and examples thereof include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, arachidic acid, behenic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, arachidonic acid, and the like. In addition, the base for neutralizing the fatty acid is not particularly limited as long as it is a base commonly used in the manufacture of soaps, such as potassium hydroxide, sodium hydroxide, triethanolamine, N-methyltaurine, ammonia, and the like.

[0094] Examples of the fats and oils include avocado oil, camellia oil, evening primrose oil, turtle oil, macadamia oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, peach kernel oil, wheat germ oil, camellia oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, tea seed oil, torreya seed oil, rice bran oil, Chinese tung oil, Japanese tung oil, jojoba oil, germ oil, triglycerol, tricaprylin, triisopalmitin, cocoa butter, coconut oil, hydrogenated coconut oil, palm oil, palm kernel oil, wood wax kernel oil, hydrogenated oil, hydrogenated castor oil, and polyoxyethylene adducts thereof.

[0095] Examples of the wax include spermaceti, beeswax, high acid value beeswax, shellac, mink wax, lanolin, lanolin acetate, liquid lanolin, carnauba wax, candelilla wax, rice bran wax, bran wax, wood wax, cotton wax, bayberry wax, lilac wax, montan wax, kapok wax, jojoba wax, sugar cane wax, lilac wax, lanolin fatty acid isopropyl ester, hexyl laurate, reduced lanolin, hard lanolin, shellac wax, polyoxyethylene lanolin alcohol ether, polyoxyethylene lanolin alcohol acetate, polyoxyethylene cholesterol ether, lanolin fatty acid polyethylene glycol ester, polyoxyethylene hydrogenated lanolin alcohol ether, and the like.

[0096] Examples of the hydrocarbon oil include paraffin, liquid paraffin, ozokerite, squalene, pristane, ceresin, vaseline, microcrystalline wax and the like.

[0097] Examples of the ester oil include myristate esters such as isopropyl myristate, butyl myristate, myristyl myristate, isocetyl myristate, octyldodecyl myristate, and 2-hexyldecyl myristate; palmitate esters such as isopropyl palmitate, cetyl palmitate, isostearyl palmitate, 2-ethylhexyl palmitate, 2-hexyldecyl palmitate, and 2-heptylundecyl palmitate; butyl stearate, isocetyl stearate, cholesterol stearate, isocetyl isostearate, 12-hydroxystearate cholesterol, and N-alkyl isostearate. Stearates such as ethylene glycol esters; laurate esters such as isopropyl laurate and hexyl laurate; linoleate esters such as ethyl linoleate and isopropyl linoleate; octanoate esters such as cetyl octanoate, hexyldecyl dimethyl octanoate, octyldodecyl dimethyl octanoate and cetyl isooctanoate; oleate esters such as decyl oleate and oleyl oleate; sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquistearate, sorbitan tristearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, sorbitan monooleate Sorbitan fatty acid ester oils such as sorbitan monoisostearate and sorbitan sesquiisostearate; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monococonut oil fatty acid ester, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monoisostearate, polyoxyethylene sorbitan tristearate and polyoxyethylene sorbitan monooleate; polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan hexastearate, polyoxyethylene sorbitan tetrastearate and polyoxyethylene sorbitan tetraoleate esters of polyoxyethylene sorbitol fatty acids such as esters of polyoxyethylene sorbitol fatty acids; lactic acid esters such as cetyl lactate and myristyl lactate; malic acid esters such as diisostearyl malate; adipate esters such as diisobutyl adipate, di-2-heptyl undecyl adipate and 2-hexyldecyl adipate; sebacic acid esters such as di-2-ethylhexyl sebacate and diisopropyl sebacic acid; succinic acid esters such as 2-ethylhexyl succinate; citrate esters such as triethyl citrate, triisocetyl citrate, triisoeicosyl citrate, triisooctyl citrate, acetyl triethyl citrate and acetyl tributyl citrate;Ethylene glycol di-2-ethylhexanoate, propylene glycol monocaprate, propylene glycol dicaprate, propylene glycol disacrylate, tri-2-ethylhexanoin, tri(caprylic acid / capric acid)glyceryl, tri-2-ethylhexanoin trimethylolpropane, triisostearate trimethylolpropane, pentaerythritol tetra-2-ethylhexanoate, tri-2-ethylhexanoin glyceryl, trimyristin, decaglycerol decastearate, decaglycerol decaoleate, decaglycerol decaisostearate, di-2-heptylundecanoic acid glyceryl, polyoxyethylene monostearate Polyol esters such as glyceryl monoolate, polyethylene glycol monooleate, diglyceryl monostearate, diglyceryl monoisostearate, diglyceryl monooleate, tetraglyceryl monostearate, polyglyceryl monooleate, polyglyceryl tristearate, polyglyceryl pentastearate, polyglyceryl pentaoleate and neopentyl glycol dicaprate; acetic acid lanolin, dipentaerythritol fatty acid ester, tri-2-heptyl undecanoate glyceryl, castor oil fatty acid methyl ester, acetylated glyceride, N-lauroyl-L-glutamic acid-2-octyldodecyl ester, ethyl laurate, etc. The powder is not particularly limited as long as it is a powder commonly used with cosmetic resins. Powders of any shape (e.g., spherical, needle-shaped, plate-shaped, etc.), particle size (smoke-shaped, microparticles, pigment-grade, etc.), particle structure (porous, non-porous, etc.), etc. can be used.

[0098] Examples of the inorganic powder include titanium oxide, zirconium oxide, zinc oxide, cerium oxide, magnesium oxide, barium sulfate, calcium sulfate, magnesium sulfate, calcium carbonate, magnesium carbonate, talc, synthetic mica, mica, kaolin, sericite, muscovite, phlogopite, red mica, biotite, lepidolite, silicic acid, silicic anhydride, aluminum silicate, magnesium silicate, magnesium aluminum silicate, calcium silicate, barium silicate, strontium silicate, metal tungstate, hydroxyapatite, vermiculite, aluminum hydroxide (Higilite), bentonite, montmorillonite, hectorite, zeolite, ceramic powder, calcium hydrogen phosphate, aluminum oxide, aluminum hydroxide, boron nitride, boron nitride, silicon dioxide, and the like.

[0099] Examples of the organic powder include starch powder, polyamide powder, polyester powder, polyethylene powder, polypropylene powder, polystyrene powder, polyurethane powder, benzoguanamine powder, polymethylbenzoguanamine powder, tetrafluoroethylene powder, polymethyl methacrylate powder, cellulose, silk powder, nylon powder, 12-nylon, 6-nylon, styrene-acrylic acid copolymer, divinylbenzene-styrene copolymer, vinyl resin, urea-formaldehyde resin, phenolic resin, fluororesin, silicone resin, acrylic resin, melamine resin, epoxy resin, polycarbonate resin, microcrystalline cellulose powder, rice starch, lauroyl lysine, and the like.

[0100] The polymer compound is not particularly limited as long as it is a polymer compound generally used in combination with a cosmetic resin. The polymer compound can be classified into natural polymer compounds, semi-synthetic polymer compounds, and synthetic polymer compounds.

[0101] Examples of the natural polymer compound include gum arabic, tragacanth gum, galactan, guar gum, carob bean gum, karaya gum, carrageenan, pectin, agar, marmelos, algae colloid (brown algae extract), starch (rice, corn, potato, wheat), glycyrrhizic acid, xanthan gum, dehydrogenated xanthan gum, dextran, succinoglycan, pullulan, collagen, casein, albumin, gelatin, and the like.

[0102] Examples of the semi-synthetic polymer compound include starch compounds such as carboxymethyl starch, methyl hydroxypropyl starch, modified potato starch, modified corn starch and hydroxypropyl starch phosphate; cellulose polymers such as methyl cellulose, nitrocellulose, ethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, sodium cellulose sulfate, hydroxypropyl cellulose, sodium carboxymethyl cellulose (CMC), crystalline cellulose and cellulose powder; and alginic acid polymers such as sodium alginate and propylene glycol alginate.

[0103] As synthetic polymer compounds, for example, vinyl polymers such as polyvinyl alcohol, polyvinyl methyl ether, polyvinyl pyrrolidone and carboxyvinyl polymer (Carbopol); polyoxyethylene polymers such as polyethylene glycol 2000, 4000, 6000; polyoxyethylene polyoxypropylene copolymer polymers; vinyl acetate polymers; acrylic polymers such as poly (meth) acrylate and polyacrylamide; polyethylene imine, cationic polymers, etc. These polymer compounds can be in any form such as solution, microparticles, and particles. In addition, the polymer compound can be dispersed or emulsified.

[0104] Examples of the preservative include alkyl p-hydroxybenzoate, benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, phenoxyethanol, dehydroacetic acid, and salts thereof.

[0105] Examples of the antioxidant include tocopherol, butylated hydroxyanisole, and dibutylhydroxytoluene.

[0106] Examples of the pH adjuster include lactic acid, citric acid, glycolic acid, succinic acid, tartaric acid, dl-malic acid, potassium carbonate, sodium hydrogen carbonate, and ammonium hydrogen carbonate.

[0107] Examples of the chelating agent include alanine, sodium edetate, sodium polyphosphate, sodium metaphosphate, phosphoric acid, and the like.

[0108] <Cosmetics> The cosmetics of the present invention can be used as beauty cosmetics, skin cosmetics, hair cosmetics, etc., by appropriately selecting other ingredients to be added to the aqueous polymer emulsion. Examples of beauty cosmetics include eyeliner, eye shadow, eyebrow pencil, mascara, nail cosmetics, blush, foundation, lipstick, etc. Examples of skin cosmetics include facial masks, sunscreens, lotions, creams, and toners. Examples of hair cosmetics include hair dyes, hair dye cosmetics, perm solutions, bleaching agents, hair foam, shampoo, and conditioners.

[0109] Example Hereinafter, the present invention will be described by way of examples. It should be noted that the present invention is not limited to the following examples. Hereinafter, unless otherwise specified, "part" means part by mass, and "%" means % by mass.

[0110] 1. Preparation of water-based polymer emulsion [Example 1] Preparation of aqueous polymer emulsion <Emulsion Polymerization Step and Neutralization / Heating Step> In a reaction container equipped with a stirrer, a thermometer, a cooler, a nitrogen inlet tube and two dropping funnels, 50 parts of water and 1.8 parts of an anionic surfactant (manufactured by Kao Corporation, trade name: Emal 2F-30, an aqueous solution of sodium lauryl sulfate (solid content concentration 30%), hereinafter also referred to as "2F-30") were added and the temperature was raised to 80°C.

[0111] Next, 5 parts of 2F-30, 3 parts of a nonionic surfactant (manufactured by Kao Corporation, trade name: Emulgen 120, HLB 15.3, polyoxyethylene lauryl ether (solid content concentration 100%), hereinafter also referred to as "E-120"), and 50 parts of water were mixed with 100 parts of the monomer mixture shown in Table 1 to prepare a monomer pre-emulsion.

[0112] The total amount of the monomer pre-emulsion and 20 parts of a 5% ammonium persulfate aqueous solution as a polymerization initiator were continuously added to the reaction container through different dropping funnels for 4 hours, and the emulsion polymerization was carried out while the liquid temperature was maintained at about 80°C. After the addition was completed, the liquid temperature was further maintained at 80°C for 2 hours. Then, after cooling to 60°C, the pH was adjusted to 8.5 with ammonia water, and then heated for 3 hours. Next, after cooling to 50°C, 0.1 parts of a defoamer SN Defoamer PC (trade name, manufactured by SAN NOPCO) was added to obtain an aqueous polymer emulsion.

[0113] <Deodorization process (process of blowing pressurized steam)> A pressurized steam supply pipe and an exhaust pipe were installed in a flask containing an aqueous polymer emulsion. After the liquid temperature was raised to 55°C, under stirring, pressurized steam with a pressure of 0.2MPa was blown into the liquid at 5 parts / hour relative to 100 parts by mass of the aqueous polymer emulsion, and the water vapor in the system was exhausted through the exhaust pipe using an exhaust pump, thereby reducing the pressure in the flask to 15KPa and maintaining the system in a state of water boiling. By blowing in pressurized steam for 5 hours, a total of 25 parts of water vapor were supplied. The pH of the obtained emulsion was adjusted to pH 8 with aqueous ammonia to obtain a low-odorized aqueous polymer emulsion.

[0114] [Examples 2 to 15, Examples 21 to 32] Production of aqueous polymer emulsions The aqueous polymer emulsions of Examples 2 to 15 and 21 to 32 were obtained in the same manner as in Example 1 except that the monomer compositions, HLB and blending amount of the nonionic surfactant were changed to those shown in Tables 1 and 2. It should be noted that the numerical values ​​in Tables 1 and 2, where no unit is described, represent "parts", and blanks represent that no unit was used.

[0115] [Example 16] Preparation of aqueous polymer emulsion An aqueous polymer emulsion of Example 16 was obtained in the same manner as in Example 9 except that the deodorization step was not performed.

[0116] [Example 17] Preparation of aqueous polymer emulsion The aqueous polymer emulsion of Example 17 was obtained in the same manner as in Example 9 except that the pressure in the container in the deodorization step was changed to 25 KPa (a state in which water does not boil).

[0117] [Examples 18 and 19] Preparation of aqueous polymer emulsion Except that the pH during the heat treatment was changed as described in Table 2, the same method as in Example 9 was carried out to obtain aqueous polymer emulsions of Examples 18 and 19.

[0118] [Example 20] Synthesis of aqueous polymer emulsion Except having changed the temperature in the heat treatment as described in Table 2, the same method as in Example 9 was carried out to obtain an aqueous polymer emulsion of Example 20.

[0119] [Comparative Examples 1 to 5] Preparation of Aqueous Polymer Emulsion Aqueous polymer emulsions of Comparative Examples 1 to 5 were obtained in the same manner as in Example 1 except that the monomer composition, HLB of the nonionic surfactant and the blending amount were changed to those shown in Table 2.

[0120] [Comparative Example 6] Preparation of Aqueous Polymer Emulsion An aqueous polymer emulsion of Comparative Example 6 was obtained in the same manner as in Example 9 except that the heat treatment was not performed.

[0121] 2. Evaluation (1) Evaluation of water-based polymer emulsions The liquid properties and physical properties of the aqueous polymer emulsions of Examples 1 to 32 and Comparative Examples 1 to 6 were evaluated. The evaluation method is as follows.

[0122] <Non-volatile content> The concentration of the nonvolatile component in the aqueous polymer emulsion was calculated by the following mathematical formula as the ratio of the residual amount after the aqueous polymer emulsion was heated at 155° C. for 30 minutes in a hot air circulation dryer.

[0123] Non-volatile content concentration (%) = (W3 / W2) × 100 Wherein, W2 is the mass of the emulsion before heating (unit: g), and W3 is the mass of the residual component after heating (unit: g).

[0124] <Viscosity> The viscosity was measured using a B-type viscometer at 25°C and 12 rpm.

[0125] <Volume Average Particle Diameter of Aqueous Polymer Emulsion> The volume average particle size is measured using a particle size analyzer UPA-EX150 manufactured by Microtrac BEL.

[0126] <Glass transition temperature of polymer> The glass transition temperature (Tg) of the polymer is calculated by the above-mentioned mathematical formula (1).

[0127] <Water resistance> The water resistance of the aqueous polymer emulsion after drying was evaluated by the method shown below. The aqueous polymer emulsion was applied on a glass plate using an applicator so that the thickness of the aqueous polymer emulsion after drying was 50 m m, and air-dried at 23°C and 50% RH for 1 day to prepare a test body. After the prepared test body was immersed in distilled water for 1 day, it was rubbed back and forth 10 times with a load of 100 g using a friction tester using a water-containing sponge, and the presence or absence of peeling and flaking was evaluated based on the following criteria.

[0128] ◎: No change was observed in the film (good) ○: The film peels off or falls off slightly (normal) △: About half of the film peeled off or fell off (slightly defective) ×: Most of the film peeled off or fell off (defective) <Oil resistance> After the test body prepared in the same manner as in the water resistance test was immersed in oleic acid for 1 day, it was rubbed back and forth 10 times with a load of 100 g using an oleic acid-containing sponge using a friction tester to evaluate the presence or absence of shedding and flaking, thereby evaluating the oil resistance of the dried aqueous polymer emulsion. The evaluation was performed according to the same criteria as in the water resistance test.

[0129] <Flexibility> In thickness 25 m The surface of the polyethylene terephthalate film is coated with an aqueous polymer emulsion so that the thickness of the aqueous polymer emulsion after drying reaches 25 m m, then dried at 50°C for 6 hours in a hot air circulation dryer, and air-dried at 23°C and 50% RH for 1 day to prepare a test body having a film formed on the surface of the polyethylene terephthalate film. The obtained test body was bent repeatedly 10 times, and the presence or absence of cracks and peeling of the film was evaluated according to the following criteria, thereby evaluating the flexibility of the film.

[0130] ○: No change was observed in the film (good) △: The film has some cracks or peeling (slightly defective) ×: Cracks or peeling occurred on the entire surface of the film (defective) <stickiness> The surface of the test piece prepared in the same manner as in the flexibility test was run with a finger, and the stickiness (tackiness) of the film was evaluated based on the touch according to the following criteria. It can be said that the less stickiness, the better the use experience.

[0131] ◎: No stickiness (good) ○: Slightly sticky (normal) △: Sticky (slightly bad) ×: Very sticky (bad) <Evaluation of odor from volatile organic compounds> 80 g of the aqueous polymer emulsion was placed in a 100 mL glass container, which was sealed with a lid. After being kept in a hot air circulation dryer at 40° C. for 1 hour, the container was immediately taken out and the odor when the lid was removed was evaluated by a sensory test according to the following criteria.

[0132] ◎: Almost no odor (extremely good) ○: Slightly smelly (good) △: Smell is slightly unpleasant ×: Has a strong odor (bad) <Concentration of Volatile Organic Compounds (Unreacted Monomers)> The concentration of unreacted monomers as volatile organic compounds was measured by gas chromatography (apparatus: GC-2014 manufactured by Shimadzu Corporation, column: DB-1 manufactured by GL Sciences, carrier gas: nitrogen, detector: hydrogen flame ionization detector). In the gas chromatography measurement, 0.5 g of the aqueous polymer emulsion, 4.0 g of ethanol and 0.3 g of a 20% calcium chloride aqueous solution were mixed and allowed to stand for 10 minutes, centrifuged at 12,000 rpm × 10 minutes, 1.5 g of the supernatant was taken, and 0.05 g of a 1% aqueous solution of ethylene glycol monomethyl ether acetate as an internal standard was added thereto to obtain a solution, and the obtained solution was used as the injection liquid for the gas chromatography.

[0133] <Concentration of alcohol derived from (A) monomer and methanol derived from (B) monomer immediately after production> The concentrations of the alcohol derived from the (A) monomer and the methanol derived from the (B) monomer in the aqueous polymer emulsion immediately after production were measured by gas chromatography (apparatus: GC-2014 manufactured by Shimadzu Corporation, column: DB-1 manufactured by GL Sciences, carrier gas: nitrogen, detector: hydrogen flame ionization detector). In the measurement of gas chromatography, 0.5 g of the aqueous polymer emulsion and 4.0 g of water were mixed, 1.5 g of which was taken, and 0.05 g of a 1% aqueous solution of ethylene glycol monomethyl ether acetate as an internal standard was added to the mixture, and the resulting solution was used as the injection liquid for the gas chromatography.

[0134] <Concentration of Alcohol Derived from (A) Monomer and Methanol Derived from (B) Monomer after Long-term Storage> The aqueous polymer emulsions obtained in the examples and comparative examples were placed in a sealed container and kept in a hot air circulation dryer at 50° C. for 28 days. The concentrations of the alcohol derived from the (A) monomer and the methanol derived from the (B) monomer were measured in the same manner as the concentrations of the alcohol derived from the (A) monomer and the methanol derived from the (B) monomer immediately after production. The obtained measured values ​​were used as the concentrations of the alcohol derived from the (A) monomer and the methanol derived from the (B) monomer after long-term storage.

[0135] The results of evaluation of the aqueous polymer emulsions of Examples 1 to 32 and Comparative Examples 1 to 6 on liquid properties, water resistance, oil resistance, flexibility, viscosity, odor of volatile organic compounds, content of volatile organic compounds (unreacted monomers), content of alcohol derived from the (A) monomer and methanol derived from the (B) monomer immediately after production, and content of alcohol derived from the (A) monomer and methanol derived from the (B) monomer after long-term storage are shown in Tables 3 and 4.

[0136] [Table 1] [Table 2] [Table 3] [Table 4] The abbreviations in the table are as follows.

[0137] <Single> EMA: Ethyl methacrylate of petroleum origin (i.e., not biomass-derived) BMA: n-butyl methacrylate of petroleum origin (i.e., not biomass-derived) BA: n-Butyl acrylate of petroleum origin (i.e., not biomass derived) 2EHA: Petroleum-derived (i.e., not biomass-derived) 2-ethylhexyl acrylate LA: Lauryl acrylate having a biomass-derived C12 linear alkyl group at the ester terminal; manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: Biomass Acrylate LA (C12 Acrylate) MMA: Methyl methacrylate of petroleum origin (i.e., not biomass-derived) MA: Methyl acrylate of petroleum origin (i.e., not biomass-derived) MAA: Methacrylic acid of petroleum origin (i.e., not biomass-derived) AA: Acrylic acid of petroleum origin (i.e., not biomass-derived) St: Styrene of petroleum origin (i.e., not biomass-derived) HEMA: 2-Hydroxyethyl methacrylate of petroleum origin (i.e., not biomass-derived) <Surfactant> 2F-30: Made by Kao Corporation, trade name: Emal 2F-30, aqueous solution of sodium lauryl sulfate (solid content concentration 30%) E-120: Made by Kao Corporation, trade name: Emulgen 120, polyoxyethylene lauryl ether (solid content concentration 100%) E-106: Made by Kao Corporation, trade name: Emulgen 106, polyoxyethylene lauryl ether (solid content concentration 100%) E-108: Made by Kao Corporation, trade name: Emulgen 108, polyoxyethylene lauryl ether (solid content concentration 100%) E-109P: Made by Kao Corporation, trade name: Emulgen 109P, polyoxyethylene lauryl ether (solid content concentration 100%) E-123P: Made by Kao Corporation, trade name: Emulgen 123P, polyoxyethylene lauryl ether E-103: Made by Kao Corporation, trade name: Emulgen 103, polyoxyethylene lauryl ether (solid content concentration 100%) E-150: Made by Kao Corporation, trade name: Emulgen 150, polyoxyethylene lauryl ether (solid content concentration 100%) According to the results of Tables 3 and 4, the aqueous polymer emulsions of Examples 1 to 32 have a very good balance between water resistance and oil resistance, a low alcohol content, and excellent storage stability, compared with Comparative Example 1 in which the composition of the (B) monomer is out of the range, Comparative Example 2 in which the composition of the (C) monomer is out of the range, Comparative Example 3 in which the amount of the nonionic surfactant is out of the range, Comparative Examples 4 and 5 in which the HLB of the nonionic surfactant is out of the range, and Comparative Example 6 in which no heat treatment is performed. In addition, the aqueous polymer emulsions of Examples 1 to 32 also have good results in terms of viscosity and low odor.

[0138] (2) Manufacturing and evaluation of cosmetics [Example 33] Production of Mascara 2 parts of methylhydroxypropylcellulose, 10 parts of talc and 45 parts of the aqueous polymer emulsion obtained in Example 1 were added to 22.3 parts of ion exchange water, and the mixture was stirred and mixed uniformly. Next, a coloring paste containing 15 parts of black iron oxide, 5 parts of glycerin and 1.5 parts of polyoxyethylene sorbitan monooleate was added to the obtained mixed solution and mixed uniformly, and 0.1 parts of fragrance and 0.1 parts of preservative were added to obtain a black mascara.

[0139] [Examples 34 to 48 and Comparative Examples 7 to 11] Production of Mascara Mascara of Examples 34 to 48 and Comparative Examples 7 to 11 were obtained in the same manner as in Example 33 except that the aqueous polymer emulsion shown in Table 5 was used. In Table 5, the numerical values ​​without units are expressed as "parts", and blanks indicate that the compound was not used (the same applies to Tables 6 to 8 below).

[0140] [Mascara reviews] The cosmetics (mascaras) of Examples 33 to 48 and Comparative Examples 7 to 11 were evaluated for water resistance, oil resistance, long-lasting properties, and stability over time by the following methods.

[0141] <Water resistance> Use an applicator to apply makeup (mascara) on the glass plate so that the thickness of the makeup (mascara) after drying is 50 m m, and air-dried at 23° C. and 50% RH for 1 day to prepare a test body. The test body was immersed in distilled water for 1 day, and the presence or absence of film peeling and flaking was evaluated based on the following criteria.

[0142] ◎: No change was observed in the film (extremely good) ○: The film peels off or falls off slightly (good) △: About half of the film peeled off or fell off (slightly defective) ×: Most of the film peeled off or fell off (defective) <Oil resistance> A test piece was prepared in the same manner as in the above water resistance test, and the test piece was immersed in oleic acid for 1 day to evaluate whether the film was peeled off or flaked off. The evaluation was performed according to the same criteria as in the above water resistance test.

[0143] <Makeup durability> The long-lasting makeup effect was evaluated by 10 panelists through a use test. The evaluation criteria were determined as follows.

[0144] ◎: All 10 people evaluated it as good.

[0145] ○: 8 or more out of 10 people evaluated it as good.

[0146] △: 5 or more out of 10 people evaluated it as good.

[0147] ×: Four or less out of ten people evaluated it as good.

[0148] <Stability over time> 40 g of cosmetics were placed in a 50 mL glass container and sealed. After being kept in a hot air circulation dryer at 40° C. for 1 month, the separation state was observed according to the following criteria to evaluate the stability over time.

[0149] (Evaluation criteria) ◎: No separation (extremely good) ○: Although some separation was observed, mixing disappeared (good) △: Separation is observed and does not disappear even after mixing (slightly poor) ×: Significant separation (poor) [Table 5] According to the results in Table 5, the cosmetics of Examples 33 to 48 are superior in water resistance, oil resistance, and long-lasting makeup properties compared to Comparative Example 7 where the composition of the (B) monomer is out of the range, Comparative Example 8 where the composition of the (C) monomer is out of the range, Comparative Example 9 where the amount of the nonionic surfactant is out of the range, and Comparative Examples 10 and 11 where the HLB of the nonionic surfactant is out of the range. In addition, the cosmetics of Examples 33 to 48 are also excellent in stability over time.

[0150] [Example 49] Production and evaluation of nail cosmetics A solution obtained by mixing 10 parts of ethylene glycol monoethyl ether, 3 parts of acetyl tributyl citrate and 7 parts of ion exchange water was slowly added to 80 parts of the aqueous polymer emulsion obtained in Example 2 and stirred until uniform, thereby obtaining a nail cosmetic. Using the obtained nail cosmetic, water resistance, oil resistance, makeup durability and stability over time were evaluated. The evaluation method was the same as that of the mascara.

[0151] [Examples 50 to 64 and Comparative Examples 12 to 16] Production and Evaluation of Nail Cosmetics Except for changing to the aqueous polymer emulsion shown in Table 6, the nail cosmetics of Examples 50 to 64 and Comparative Examples 12 to 16 were obtained in the same manner as in Example 49. Furthermore, using the obtained nail cosmetics, water resistance, oil resistance, long-lasting properties and stability over time were evaluated by the same evaluation methods as in the case of mascara.

[0152] [Table 6] According to the results of Table 6, the cosmetics of Examples 49 to 64 are superior in water resistance, oil resistance and long-lasting makeup properties compared with Comparative Example 12 where the composition of the (B) monomer is out of the range, Comparative Example 13 where the composition of the (C) monomer is out of the range, Comparative Example 14 where the amount of the nonionic surfactant is out of the range, and Comparative Examples 15 and 16 where the HLB of the nonionic surfactant is out of the range. In addition, the cosmetics of Examples 49 to 64 are also good in stability over time.

[0153] [Example 65] Production and evaluation of eyeliner 1 part of polyoxyethylene (20) sorbitan monooleate, 0.15 parts of carboxymethyl cellulose, and 14 parts of iron oxide were added to 33.9 parts of ion exchange water, and the mixture was uniformly stirred and mixed. Then, 5 parts of glycerol and 1 part of acetyl tributyl citrate were added, and 45 parts of the aqueous polymer emulsion obtained in Example 1 were gradually added and stirred until uniform, thereby obtaining an eyeliner. The obtained eyeliner was used to evaluate water resistance, oil resistance, makeup durability, and stability over time. The evaluation method was the same as that of the mascara.

[0154] [Examples 66 to 80 and Comparative Examples 17 to 21] Production and Evaluation of Cream Eyeliner Eyeliners of Examples 66 to 80 and Comparative Examples 17 to 21 were obtained by the same method as in Example 65 except that the formulation was changed to that shown in Table 7. Furthermore, using the obtained eyeliners, water resistance, oil resistance, long-lasting properties, and stability over time were evaluated by the same evaluation methods as in the case of mascara.

[0155] [Table 7] According to the results of Table 7, the cosmetics of Examples 65 to 80 are superior in water resistance, oil resistance, and long-lasting makeup properties compared to Comparative Example 17 where the composition of the (B) monomer is out of the range, Comparative Example 18 where the composition of the (C) monomer is out of the range, Comparative Example 19 where the amount of the nonionic surfactant is out of the range, and Comparative Examples 20 and 21 where the HLB of the nonionic surfactant is out of the range. In addition, the cosmetics of Examples 65 to 80 also have good stability over time.

[0156] [Example 81] Production and evaluation of foundation 5 parts of the aqueous polymer emulsion obtained in Example 2, 0.5 parts of bentonite, 1 part of polyoxyethylene sorbitan monostearate, 10 parts of propylene glycol, 0.1 parts of preservatives, and 52.4 parts of ion exchange water were mixed and dispersed uniformly at 70°C using a homogenizer. In addition, triethanolamine was used to adjust the pH to 7.0. Next, 3 parts of talc, 5 parts of titanium dioxide, 0.5 parts of red iron oxide, and 1 part of iron oxide were mixed and fully mixed, and added to the previous dispersion. 2.5 parts of stearic acid, 7 parts of isocetyl alcohol, 2 parts of monostearate glyceryl, 2 parts of liquid lanolin, and 8 parts of liquid paraffin were mixed and dissolved at 80°C to prepare an oil phase. The oil phase was put into the previous aqueous phase and emulsified using a homogenizer at 70°C. Then, it was cooled to room temperature to obtain a foundation. The obtained foundation was used to evaluate water resistance, oil resistance, makeup durability, and stability over time. The evaluation method is the same as that of mascara.

[0157] [Examples 82 to 96 and Comparative Examples 22 to 26] Production and Evaluation of Foundation The foundations of Examples 82 to 96 and Comparative Examples 22 to 26 were obtained in the same manner as in Example 81 except that the formulation was changed to that shown in Table 8. Furthermore, using the obtained foundations, water resistance, oil resistance, long-lasting properties, and stability over time were evaluated in the same manner as in the case of the mascara.

[0158] [Table 8] According to the results of Table 8, the cosmetics of Examples 81 to 96 are superior in water resistance, oil resistance, and long-lasting makeup properties compared to Comparative Example 22 where the composition of the (B) monomer is out of the range, Comparative Example 23 where the composition of the (C) monomer is out of the range, Comparative Example 24 where the amount of the nonionic surfactant is out of the range, and Comparative Examples 25 and 26 where the HLB of the nonionic surfactant is out of the range. In addition, the cosmetics of Examples 81 to 96 also have good stability over time.

[0159] The present invention is not limited to the above-mentioned embodiments, and also includes various modifications and variations within the scope of the present invention without departing from the main purpose of the present invention. Therefore, it should be understood that according to the above teachings, various combinations, forms, and other combinations and forms including only one element, more than one element, or less than one element also fall into the category and scope of the present invention.

Claims

1. A water-based polymer emulsion for cosmetics, characterized in that: Containing resin particles, The resin particles contain a structural unit derived from the following (A) monomer and a structural unit derived from the following (C) monomer, and optionally contain a structural unit derived from the following (B) monomer, With respect to 100 mass % of the total of the structural units derived from the monomers constituting the resin particles, the structural units derived from the following (A) monomers account for 70 to 99.9 mass %, the structural units derived from the following (B) monomers account for 0 to 10 mass %, and the structural units derived from the following (C) monomers account for 0.1 to 10 mass %. The resin particles further contain 0.1 to 10 parts by mass of a nonionic surfactant having an HLB of 10.0 to 17.0, based on 100 parts by mass of the total monomers constituting the resin particles. The concentration of the alcohol derived from the alkyl group of the monomer constituting the resin particles is 150 ppm or less, (A) an alkyl (meth)acrylate having an alkyl group having 2 to 12 carbon atoms, (B) an unsaturated monomer having a methyl ester group, (C) at least one monomer selected from the group consisting of unsaturated carboxylic acids and unsaturated carboxylic anhydrides.

2. The aqueous polymer emulsion for cosmetics according to claim 1, wherein The glass transition temperature of the polymer constituting the resin particles is -20°C to 20°C.

3. The aqueous polymer emulsion for cosmetics according to claim 1, wherein The (C) monomer is methacrylic acid.

4. The aqueous polymer emulsion for cosmetics according to claim 1, wherein The (B) monomer is methyl (meth)acrylate.

5. A method for producing an aqueous polymer emulsion for cosmetics, characterized in that: A method for producing the aqueous polymer emulsion for cosmetics according to any one of claims 1 to 4, The manufacturing method comprises the following steps: A step of obtaining a polymer emulsion by conducting emulsion polymerization under the following conditions: the content of the (A) monomer is 70 to 99.9% by mass, the content of the (B) monomer is 0 to 10% by mass, the content of the (C) monomer is 0.1 to 10% by mass, and the content of the (A) monomer is 70 to 99.9% by mass, relative to 100 parts by mass of the total monomers used in the polymerization, relative to 100 parts by mass of the total monomers used in the polymerization, and 0.1 to 10 parts by mass of a nonionic surfactant having an HLB of 10.0 to 17.0 is contained; A step of adding an alkaline compound to the polymer emulsion to neutralize to a pH range of 7.0 to 10.0, and heating to a temperature of 50° C. to 90° C.; as well as The step of removing volatile organic compounds from the aqueous polymer emulsion by setting the pressure in a treatment container capable of reducing pressure to a range of 12 KPa to 57 KPa, maintaining the water in the treatment container in a boiling state, and supplying pressurized steam into the treatment container.

6. A cosmetic, characterized in that: A cosmetic aqueous polymer emulsion comprising the cosmetic aqueous polymer emulsion according to any one of claims 1 to 4.

Images