JP2784773B2 - Ultraviolet-absorbing polymer fine particles for cosmetics and method for producing the polymer fine particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing ultraviolet-absorbing polymer fine particles having a substantially spherical shape which is particularly useful as a main component of sunscreen cosmetics.

[Background of the Invention]

Various ultraviolet absorbers are added to cosmetics such as foundation, white powder, lipstick and the like for the purpose of sunscreen. Ultraviolet absorbers added to such sunscreen cosmetics absorb ultraviolet rays in a wavelength range of 280 to 320 nm which cause inflammation of the skin. It is desirable that such an ultraviolet absorber is harmless to the skin and the human body, does not adversely affect the applicability of the cosmetic, that is, the usability, and does not impair the transparency of the cosmetic.

[Conventional technology]

Conventionally, quinine salts,
Para-aminobenzoic acid and its derivatives, benzophenone derivatives, salicylic acid derivatives and the like have been provided. However, since such an ultraviolet absorber is a low-molecular compound, if it is added to cosmetics as it is, it is easily absorbed by the human body through the skin and is highly irritating. Furthermore, it is easy to fall off due to sweat or the like, and there is a problem in fixability on the skin surface. Therefore, attempts have been made to block or bond such a low molecular ultraviolet absorber in a polymer. For example, JP-A-61-66715 discloses ultraviolet-absorbing epoxy-based spherical fine particles obtained by emulsifying an epoxy-based compound in which an ultraviolet-absorbing agent is dissolved and curing the same with an amine-based curing agent. JP-A-62-93220 discloses a method for producing an ultraviolet-absorbing polymer powder by mixing a vinyl monomer with an ultraviolet absorber and performing emulsion polymerization. Further, JP-A-61-111360 discloses a silicone resin emulsion in which an ultraviolet absorbent is chemically bonded.

[Problems to be solved by the invention]

However, in the above-mentioned conventional method, in the case of the ultraviolet-absorbing epoxy spherical fine particles, the ultraviolet-absorbing agent is simply dissolved in the epoxy resin and sealed off, so that the ultraviolet-absorbing agent leaches out of the epoxy resin and irritates the skin. There is a risk of irritation, and in the case of a silicone resin emulsion in which an ultraviolet absorber is chemically bonded, a two-step process of preparing a silicone resin emulsion and then reacting the ultraviolet absorber is required. Further, in the above-mentioned conventional method, it is difficult to obtain polymer particles having a uniform particle size and a high sphericity, which deteriorates the feeling of use of the cosmetic.

[Means for solving the problem]

The present invention provides the following structure as means for solving the above conventional problems. Here, R ₁ is an alkyl group or a substituted alkyl group, and R ₂ is a hydrogen or an alkyl group.

A single or two or more ultraviolet absorbing monomers having
What provides UV-absorbing polymer fine particles for cosmetics having a substantially spherical shape, comprising a copolymer of the UV-absorbing monomer and another vinyl monomer copolymerizable alone or in combination of two or more kinds. Is further dispersed in water with a polymer fine particle and a swelling agent for the polymer fine particles to prepare a swelled aqueous dispersion of the polymer fine particles, and the ultraviolet absorbent monomer in the aqueous dispersion. A single or a mixture of two or more thereof and a comonomer consisting of one or more of other vinyl monomers copolymerizable with the ultraviolet absorbing monomer are mixed, and the comonomer is mixed. An object of the present invention is to provide a method for producing ultraviolet absorbent polymer fine particles for cosmetics having a substantially spherical shape, which is absorbed by a swollen body of the polymer fine particles and is polymerized.

[Ultraviolet absorbing monomer] The ultraviolet absorbing monomer used in the present invention has the following structure.

Here, R ₁ is an alkyl group or a substituted alkyl group,
R ₂ is hydrogen or an alkyl group. More specifically,
R ₁ is a linear or branched alkyl group, and the alkyl group may be substituted with a hydroxyl group, a nitro group, an amino group, a benzyl group, a halogen atom, or the like. It is preferable that the alkyl group is a lower alkyl group having 5 or less, and that R ₂ has 2 or less carbon atoms in the case of an alkyl group from the viewpoint of polymerizability.

(Vinyl monomer)

Other vinyl monomers copolymerizable with the ultraviolet absorbing monomer include methyl acrylate, ethyl acrylate, n
-Butyl acrylate, iso-butyl acrylate, 2
-Ethylhexyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, methyl vinyl ether,
Ethyl vinyl ether, n-propyl vinyl ether,
iso-butyl vinyl ether, n-butyl vinyl ether, styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, ethylene, propylene, isoprene, chloroprene, butadiene, etc. It is also possible to use vinyl monomers having a functional group such as a carboxyl group, a hydroxyl group, a methylol group, an amino group, an acid amide group, and a glycidyl group. Among the vinyl monomers having such a functional group, those having a carboxyl group include acrylic acid,
Examples of those having a hydroxyl group such as methacrylic acid and itaconic acid include β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, and allyl alcohol. -Methylol acrylamide, N-methylol methacrylamide, etc., those having an amino group include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, etc., those having an acid amide group include acrylamide, methacrylamide, etc. Glycidyl acrylate, glycidyl methacrylate, glycidyl allyl ether and the like are exemplified. The above examples do not limit the invention. Further, in the present invention, a monomer having a hydrolyzable silyl group as a functional group as a vinyl monomer having a functional group, for example, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, etc. Can also be used. The above examples also do not limit the present invention.

(Comonomer)

A single monomer or a mixture of two or more of the above-mentioned ultraviolet-absorbing monomers and a mixture of the above-mentioned other vinyl monomers alone or a mixture of two or more thereof are used as a comonomer. The monomer is desirably contained in the above comonomer in an amount of 0.01 to 30 mol%, and more desirably 0.2 to 7 mol% of the vinyl monomer having the functional group among the above vinyl monomers.

〔Production method〕

Desirable production methods are a precipitation polymerization method and a seed polymerization method.

A precipitation polymerization method In the precipitation polymerization method, a single or a mixture of two or more of the ultraviolet absorbing monomers, and a single or two or more of other vinyl monomers copolymerizable with the ultraviolet absorbing monomers Is polymerized in a solvent in which the comonomer is soluble and the copolymer based on the comonomer is insoluble. By such polymerization, the copolymer is precipitated in the solvent as spherical particles having a uniform particle size.

(Solvent) The solvent used in the present method dissolves the above comonomer,
The copolymer is insoluble based on the comonomer, and contains methanol, ethanol, isopropanol, n-
Examples thereof include lower alcohols such as butanol, mixed solvents of the lower alcohols and water, and nonpolar solvents such as n-hexane and n-heptane. The above examples do not limit the invention.

(Dispersion Stabilizer) As the dispersion stabilizer, a polymer soluble in the above solvent, for example, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyvinyl alcohol, polyvinyl alkyl ether, or the like is used. Further, a surfactant may be used in combination. As the surfactant, any of anionic, nonionic, and cationic surfactants are used. For example, higher alcohol sulfate (Na salt or amine salt) as the anionic surfactant,
Alkyl allyl sulfonate (Na salt), alkyl naphthalene sulfonate, alkyl phosphate, dialkyl sulfosuccinate, rosin soap, nonionic polyoxyethylene alkyl ether,
Polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkyl amide, sorbitan alkyl ester, polyoxyethylene sorbitan alkyl ester, cationic trimethylaminoethyl alkyl amide halogenide, alkylpyridinium Sulfates, alkyltrimethylammonium halides and the like. The above examples also do not limit the invention.

The polymer is usually dissolved in the solvent in an amount of 0.5 to 5% by weight, and the surfactant is usually dissolved in the solvent in an amount of about 0.1 to 1% by weight. The polymer and the surfactant may be used in combination of two or more.

(Polymerization) As the polymerization initiator used for the polymerization of the comonomer, an oil-soluble initiator such as lauroyl peroxide, benzoyl peroxide, cumene hydroperoxide, and azobisisobutyronitrile is used. The oil-soluble initiator is usually added in an amount of about 0.1 to 2% by weight based on the above comonomer. The above comonomer is usually mixed in an amount of about 10 to 30% by weight based on the solvent. The mixture of the comonomer and the solvent is then used with the oil-soluble initiator, a stirrer, a condenser,
The polymerization is usually carried out by heating and stirring at about 50 to 80 ° C. in a reactor equipped with a thermometer or the like. At this time, it is desirable to replace most of the air in the reactor with an inert gas such as nitrogen gas or argon gas in order to smooth the polymerization.

As the comonomer polymerizes, the monomer becomes a polymer and precipitates out in the solvent as a true spherical powder. After completion of the polymerization, the obtained spherical polymer powder is separated from the solvent by filtration, centrifugation, or the like, washed if necessary, dried at room temperature or heated.

Thus, the spherical polymer powder of the present invention is obtained. The diameter of the spherical polymer powder is affected by the types of the comonomer and the solvent, but is in the range of about 1 to 10 μm and is uniform. It becomes something.

B. Seed Polymerization Method In the seed polymerization method, a polymer fine particle and a swelling agent for the polymer fine particle are dispersed in water to prepare a swelled aqueous dispersion of the polymer fine particle, and the ultraviolet absorption is contained in the aqueous dispersion. A single monomer or a mixture of two or more of the hydrophilic monomers and a comonomer consisting of one or two or more of other vinyl monomers copolymerizable with the ultraviolet absorbing monomer, The comonomer is absorbed into the swelled polymer fine particles and polymerization is carried out. By such polymerization, the copolymer is collected as true spherical particles having a uniform particle size, similarly to the precipitation polymerization method.

(Polymer Fine Particles) Polymer fine particles used as seeds are fine particles of a polymer swellable in an organic solvent as a swelling agent, and include polystyrene, polymethacrylate, polyacrylate, polyvinyl chloride, polyvinyl acetate, polyacrylonitrile, and styrene. A butadiene copolymer or the like is exemplified, and the particle size of the polymer fine particles is usually 1 μm or less, and preferably about 0.2 to 0.9 μm.

(Swelling agent) As swelling agents for the polymer fine particles, methanol, ethanol, n-butanol, ethyl acetate, n-butyl acetate, acetone, methyl ethyl ketone, toluene, xylene, n-hexane, n-heptane, n-octane, methylene Examples thereof include organic solvents such as chloride, 1,2-dichloroethane, 1,2,3-trichloroethylene, 1-chlorododecane, dimethylformamide, and tetrahydrofuran. Preferably, an organic solvent having a solubility in water of 0.02% by weight or less is used. Two or more swelling agents may be mixed.

(Comonomer) The comonomer used in the present method is the same UV-absorbing monomer as the co-weight used in the precipitation polymerization method, and another copolymerizable with the UV-absorbing monomer. It is a mixture with a vinyl monomer.

(Polymerization) In the polymerization, usually, the polymer fine particles are first dispersed in water and then the swelling agent is dispersed in the water, or the swelling agent is first dispersed in water and then the polymer fine particles are dispersed in the water. Let it. In this case, a part of the swelling agent may be mixed with the polymer fine particles. In order to stably disperse the polymer fine particles and the swelling agent in water, the same surfactant as used in the precipitation polymerization method and / or a water-soluble polymer such as polyvinyl alcohol, carboxymethylcellulose, sodium alginate, and sodium polyacrylate are usually used. Use molecules.

When the polymer fine particles and the swelling agent are dispersed in water as described above, the polymer fine particles are swelled by the swelling agent, and as a result, an aqueous dispersion of a swelled body of the polymer fine particles is prepared. Then, the above-mentioned comonomer is dispersed in the aqueous dispersion, and the swollen body absorbs the comonomer and performs polymerization. The initiator used for the polymerization of the comonomer may be the same as that used in the precipitation polymerization method,
The initiator is usually dissolved in the swelling agent and / or the comonomer. The polymerization is usually carried out at a temperature of about 60 to 80 ° C., preferably in an inert gas atmosphere. In this way, spherical polymer fine particles having a uniform particle size can be obtained. The obtained polymer fine particles are collected by filtration, centrifugation, or the like, and, if desired, washed with water and dried. Thus, the spherical polymer powder of the present invention is obtained, and the diameter of the particles of the spherical polymer powder is affected by the diameter of the polymer fine particles serving as seeds. Things.

[Action]

When the above-mentioned UV-absorbing monomer is copolymerized with another vinyl monomer copolymerizable with the monomer, the UV-absorbing monomer is incorporated into the copolymer. Further, a comonomer of the ultraviolet absorbing monomer and another vinyl monomer copolymerizable with the monomer is soluble and a copolymer based on the comonomer is insoluble. In such a solvent, the comonomer precipitates as true spherical particles having a uniform particle size in the solvent. Further, when the comonomer is dispersed in the polymer powder aqueous dispersion swollen by the swelling agent, the comonomer is absorbed in the swollen body and polymerized. In this way, the comonomer is polymerized using the polymer powder as a seed to obtain spherical polymer particles having a uniform particle size.

〔The invention's effect〕

Therefore, in the present invention, since the ultraviolet absorbing monomer is incorporated into the copolymer by copolymerization, the reaction can be produced in a very simple manner in one step, and in the polymer, Since the UV-absorbing monomer is not released, the UV-absorbing monomer is not absorbed into the body from the skin, so that a sunscreen cosmetic having no skin irritation can be provided. Further, the obtained copolymer has a uniform particle diameter and is substantially spherical, so that a cosmetic having extremely good coatability and excellent feeling in use is provided.

〔Example〕

Example 1 (Production of Copolymer A) A solution prepared by dissolving 4 parts by weight of polyvinylpyrrolidone in 160 parts by weight of isopropanol was charged into a reactor equipped with a stirrer, a condenser, a thermometer, and a gas inlet tube, and further absorbed with ultraviolet light. Monomer having the following production as a reactive monomer A solution obtained by dissolving 0.3 parts by weight of benzoyl peroxide in a comonomer obtained by mixing 2.8 parts by weight and 28 parts by weight of styrene is added, and the mixture is heated to 70 ° C. with stirring at 350 rpm and reacted for 24 hours. . After completion of the reaction, the polymer particles obtained by cooling to room temperature are collected by centrifugation, washed with isopropanol, and dried at 70 ° C. for 2 hours. The obtained fine particles of the ultraviolet absorbing copolymer A are spherical and have a particle diameter of 4.5 ± 0.3 μm.

Example 2 (Production of Copolymer B) In a beaker, 0.3 parts by weight of sodium lauryl sulfate was added to 100 parts of water.
The dissolved solution was filled into a solution, and 2.5 parts by weight of benzoyl peroxide were added to 12.5 parts by weight of 1,2-dichloroethane and 1 part by weight.
-A solution of 17.5 parts by weight of chlorododecane dissolved in the mixed swelling agent was added, and the mixture was stirred with a homogenizer to disperse the swelling agent such that the diameter of the droplet was 0.5 μm or less.

The same reactor as in Example 1 was charged with 100 parts by weight of an aqueous polystyrene dispersion having a particle size of 0.63 μm (solid content concentration: 10% by weight), and 20 parts by weight of acetone was further added. The mixture is poured and gently stirred at 35 ° C. for 24 hours to swell the polystyrene particles with the swelling agent. Next, 200 parts by weight of methyl methacrylate, 440 parts by weight of styrene,
Monomer having the following structure as an ultraviolet absorbing monomer Combination of 64 parts by weight of sodium lauryl sulfate
The comonomer was poured into the reactor together with a solution prepared by dissolving 0.7 parts by weight of water in 4000 parts by weight of water and stirred at 40 rpm for 2 hours at a rotation speed of 400 rpm. Let it absorb. Thereafter, the mixture was heated to 65 ° C. and reacted for 8 hours, and then cooled to room temperature. The obtained polymer particles were collected by filtration, washed with water, and dried at 75 ° C. for 1.5 hours. The obtained ultraviolet-absorbing copolymer B fine particles have a true spherical shape of 2.4 ± 0.3 μm.
Having a uniform particle size.

Example 3 (Production of solid white powder A) The following components were blended according to the following procedure to produce solid white powder A.

Copolymer A 15.0 parts by weight Talc 15.0 parts by weight Titanium oxide 18.0 parts by weight Iron oxide 10.0 parts by weight Stearic acid 2.0 parts by weight Lanolinic acid 2.0 parts by weight Squalane 3.0 parts by weight Preservatives, perfume Appropriate amount Other than copolymer A in the above composition After the components are sufficiently mixed in a blender and pulverized by a pulverizer, the copolymer A is added, mixed again uniformly, and pressed into a predetermined shape to obtain a solid white powder A.

Example 4 (Production of Solid White Powder B) Solid white powder B was produced in the same procedure as in Example 3 except that the copolymer A was replaced with the copolymer B.

Comparative Example 1 (Production of Solid White Powder C) The following components were sufficiently mixed in a blender and pressed into a predetermined shape to produce a solid white powder C.

Particulate titanium 30 parts by weight Talc 50 parts by weight Titanium oxide 3 parts by weight Iron oxide 10 parts by weight Stearic acid 2 parts by weight Lanolinic acid 2 parts by weight Squalane 3 parts by weight Preservative, perfume Appropriate amount Comparative Example 2 (production of solid white powder D) The components were sufficiently mixed by a blender and pressed into a predetermined shape to produce a solid white powder D.

Nylon spheres 13.5 parts by weight Talc 50.0 parts by weight Titanium oxide 18.0 parts by weight Iron oxide 10.0 parts by weight Stearic acid 2.0 parts by weight Lanolinic acid 2.0 parts by weight Squalane 3.0 parts by weight p-aminobenzoic acid derivative 1.5 parts by weight Preservative, perfume Suitable amount Example 5 (Production of Sunscreen Cream E) After the following components are sufficiently mixed, the mixture is sufficiently mixed and dispersed by a homomixer while heating to a temperature at which components other than the copolymer A are melted, and then cooled to produce a sunscreen cream E.

Liquid paraffin 35 parts by weight Isopropyl myristate 30 parts by weight Carnauba wax 7 parts by weight Beeswax 3 parts by weight Lanolin alcohol 5 parts by weight Lanolin acetate 5 parts by weight Copolymer A 15 parts by weight Preservative, perfume Suitable amount Example 6 (sunscreen cream F Production) A sunscreen cream F was produced in the same manner as in Example 5 except that the copolymer A in Example 5 was replaced with the copolymer B.

Comparative Example 3 (Production of Sunscreen Cream G) After the following components were sufficiently mixed, the components other than the fine particle titanium were heated and melted, sufficiently mixed and dispersed by a homomixer, and cooled to produce a sunscreen cream G.

Particulate titanium 30.0 parts by weight Liquid paraffin 29.0 parts by weight Isopropyl myristate 25.0 parts by weight Carnaubauro 5.5 parts by weight Beeswax 2.5 parts by weight Lanolin alcohol 4.0 parts by weight Lanolin acetate 4.0 parts by weight Preservatives, perfume Appropriate amount Comparative example 4 (manufacture of sunscreen cream H) After thoroughly mixing the following components, components other than the nylon balls are heated and melted, sufficiently mixed and dispersed by a homomixer, and cooled to produce a sunscreen cream H.

Liquid paraffin 35.0 parts by weight Isopropyl myristate 30.0 parts by weight Carnauba wax 7.0 parts by weight Beeswax 3.0 parts by weight Lanolin alcohol 5.0 parts by weight Lanolin acetate 5.0 parts by weight p-aminobenzoic acid derivative 1.5 parts by weight Nylon spheres 13.5 parts by weight The solid white powders A to D and the sunscreen creams E to H were tested for use feeling (elongation), transparency, ultraviolet blocking effect, and sweat extraction test. The test method is as follows.

1 Usability (Elongation) and Transparency Ten female panelists sensually tested the usability and transparency when applied to the skin.

◎: very good, ：: good, Δ: slightly bad, ×: bad The above four points were evaluated.

2 UV blocking effect Apply to the skin of 10 female panelists, expose the skin to sunlight for 2 hours on a sunny day at Okinawa Moon Beach in summer, wipe off the sample, observe the skin underneath, and evaluate the following 4 points Was.

◎: little sunburn, ○: considerable sunburn, Δ: severe sunburn, ×: severe sunburn with irritation The determination was made by measuring the absorbance in the range of 250 to 450 μm.

 The results of the above test are shown in Table 1.

According to Table 1, the samples A, B, E, and F using the copolymers A and B, which are the ultraviolet-absorbing polymer powders of the present invention, are rich in feeling of use and transparency, and have a sufficient ultraviolet light blocking effect. It is clear that the UV-absorbing monomer in the copolymer has a sufficient UV-absorbing effect, and that the monomer is not extracted by sweat, but samples C and G using fine titanium particles are used. Shows that the feeling of use is particularly inferior in use, and that the samples D and H using a low molecular ultraviolet absorber are extracted by sweat.

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI C08L 33/14 C08L 33/14 (56) References JP-A-63-139958 (JP, A) JP-A-51-76345 (JP) JP-A-56-163140 (JP, A) JP-A-2-70711 (JP, A) JP-B-42-22685 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB Name) C08F 2/00-2/44 C08F 20/00-20/40 C08F 120/00-120/40 C08F 220/00-220/40 C08L 33/00-33/16 A61K 7/40-7/44

Claims (2)

(57) [Claims] 1. The following structure: Here, R ₁ is an alkyl group or a substituted alkyl group, and R ₂ is a hydrogen or an alkyl group. A single or two or more ultraviolet absorbing monomers having
An ultraviolet absorbent polymer for cosmetics, comprising a copolymer of one or more of other vinyl monomers copolymerizable with the ultraviolet absorbent monomer, and having a substantially spherical shape. Fine particles 2. A swelled aqueous dispersion of polymer fine particles is prepared by dispersing polymer fine particles and a swelling agent for the polymer fine particles in water, and the following structure is prepared in the aqueous dispersion. Here, R ₁ is an alkyl group or a substituted alkyl group, and R ₂ is a hydrogen or an alkyl group. A single monomer or a mixture of two or more of the ultraviolet-absorbing monomers having a comonomer consisting of one or two or more other vinyl monomers copolymerizable with the ultraviolet-absorbing monomer. Mixing the comonomer in the swollen body of the polymer fine particles and polymerizing the mixture, and producing the ultraviolet absorbent polymer fine particles for cosmetics having a substantially true spherical shape.