JP6186704B2 - Ultraviolet shielding particles, ultraviolet shielding dispersion, cosmetic, and method for producing ultraviolet shielding particles - Google Patents

Description

  The present invention relates to an ultraviolet shielding particle, an ultraviolet shielding dispersion, a cosmetic, and a method for producing the ultraviolet shielding particle, and more particularly, various cosmetics such as skin care cosmetics, makeup cosmetics, and body care cosmetics, in particular, an ultraviolet shielding ability is required. UV shielding particles suitable for whitening skin care cosmetics, base makeup for makeup cosmetics, and sunscreens for body care cosmetics, UV shielding dispersions containing the UV shielding particles, cosmetics, and UV shielding The present invention relates to a method for producing particles.

  Conventionally, as an ultraviolet shielding agent used in cosmetics, there are an inorganic ultraviolet shielding agent and an organic ultraviolet absorber, which are properly used depending on the application. Since these inorganic ultraviolet shielding agents and organic ultraviolet absorbers have different wavelengths of ultraviolet rays that can be shielded according to their types, cosmetics in which these are appropriately combined are prescribed.

  In particular, inorganic ultraviolet shielding agents scatter or reflect ultraviolet rays with a physical mechanism, and therefore have little effect on the skin, and are used in a wide range of sunscreens from infants to adults. As this inorganic ultraviolet shielding agent, zinc oxide, titanium oxide, etc., which have high hiding power against ultraviolet rays and are also used as white pigments, are suitable.

However, when zinc oxide or titanium oxide is applied to cosmetics, when the average dispersed particle size is 0.1 μm or more, the cosmetics are whitened, the transparency is impaired, and the natural finish cannot be achieved. there were.
Moreover, it is difficult to disperse zinc oxide or titanium oxide in cosmetics with an average dispersed particle diameter of 0.1 μm or less. Moreover, even if it was able to be dispersed, such zinc oxide and titanium oxide had high surface activity and had a rough feel when contacted with the skin. Further, when the primary particle diameter of zinc oxide or titanium oxide or the average dispersed particle diameter in the cosmetic is large, there is a problem that the transparency of the cosmetic is lowered.

On the other hand, organic ultraviolet absorbers chemically absorb energy and convert it into thermal energy, preventing ultraviolet rays from penetrating into skin cells. Compared to inorganic ultraviolet shielding agents, even a small amount has a high ultraviolet shielding effect and is used as a sunscreen for adults. This organic ultraviolet absorber is advantageous in that it does not become whitish when applied to the skin and is highly transparent as compared with an inorganic ultraviolet shielding agent.
Examples of such organic ultraviolet absorbers include dibenzoylmethane compounds, benzophenone derivatives, paraaminobenzoic acid derivatives, methoxycinnamic acid derivatives, salicylic acid derivatives and the like, and particularly UV-A absorbers that absorb near ultraviolet rays. Dibenzoylmethane-based compounds, particularly 4-tert-butyl-4′-methoxydibenzoylmethane (Avobenzone) is widely used.

  However, since organic ultraviolet absorbers are insoluble in water, it is necessary to dissolve them in a specific non-aqueous solvent in order to exert their ultraviolet absorption effect. There was a problem that the degree of freedom decreased. Furthermore, when a non-aqueous solvent is blended with cosmetics, there is a problem that a sticky feeling is generated.

  In addition, when these inorganic UV shielding agents and organic UV absorbers are used in combination, the organic UV absorbers are recrystallized due to the influence of metal ions contained in the inorganic UV shielding agent, and the cosmetics are altered, discolored and used. There is a risk of lowering the feeling. Thus, when formulating cosmetics, there has been a problem that inorganic ultraviolet shielding agents and organic ultraviolet absorbers cannot be freely mixed.

Therefore, in order to solve these problems, an average particle diameter of 0.1 μm to 1 μm having high transparency and excellent usability is obtained by including a metal oxide having an ultraviolet shielding ability in an acrylic resin. Resin particles have been proposed (Patent Document 1).
The resin particles suppress crystallization of the organic ultraviolet absorbent by preventing direct contact between the organic ultraviolet absorbent and the metal oxide.

In addition, as the resin particles that suppress the skin irritation of the organic ultraviolet absorber, a monomer that forms a (meth) acrylic resin in which the organic ultraviolet absorber is dissolved is dispersed in an aqueous medium to perform a polymerization reaction. And a (meth) acrylic resin containing no organic ultraviolet absorber formed on the surface of the core material part. There has been proposed a resin particle having a surface layer portion made of (Patent Document 2).
The resin particles suppress crystallization of the organic ultraviolet absorbent by preventing the organic ultraviolet absorbent from coming into direct contact with the metal oxide.

Republished WO2011 / 34032 Japanese Patent Application Laid-Open No. 07-291837

  However, in the resin particles encapsulating the metal oxide as described in Patent Document 1 described above, a certain amount or more of the resin particles must be added to the cosmetic in order to obtain desired ultraviolet shielding properties. There has been a problem that the degree of freedom of blending in cosmetics is reduced. Therefore, resin particles having higher ultraviolet shielding properties have been demanded.

  The present invention has been made in view of the above circumstances, and has a higher ultraviolet shielding effect than conventional ultraviolet shielding agents. In addition to a water-in-oil type (W / O type), an oil-in-water type ( It is an object of the present invention to provide an ultraviolet shielding particle, an ultraviolet shielding dispersion, a cosmetic, and a method for producing the ultraviolet shielding particle, which can be incorporated into a cosmetic material of O / W type.

  As a result of intensive studies in order to solve the above problems, the inventors of the present invention contain a metal oxide having an ultraviolet shielding property in the second resin on the surface of the core part made of the first resin. By adhering the resulting resin composition to a coating film or island-like material, the ultraviolet ray shielding effect is enhanced as compared with conventional resin particles containing a metal oxide, and the oil-in-water type (O / W type) The present invention was completed by finding that it can also be applied to the cosmetic formulation of (1).

  That is, the ultraviolet shielding particle of the present invention is a resin containing a metal oxide having ultraviolet shielding properties in the second resin on the entire surface of the core part made of the first resin or at one or more locations on the surface. The composition is attached to form a first coating film or one or more first islands.

  A resin composition containing an organic ultraviolet absorber in a third resin is attached to the surface of the first coating film or the surface of the core part to which the first island-like substance is attached. The second coating film or one or more second islands may be used.

  The ultraviolet shielding dispersion of the present invention is characterized in that any one or two of the ultraviolet shielding particles of the present invention are dispersed in a dispersion medium.

  The cosmetic of the present invention comprises one or more selected from the group of the ultraviolet shielding particles of the present invention and the ultraviolet shielding dispersion of the present invention.

  The method for producing ultraviolet shielding particles according to the present invention includes a step of dispersing resin particles that form a core material portion made of a first resin in water to form a resin particle-containing aqueous dispersion, and a metal oxide having ultraviolet shielding properties. In a second resin monomer containing a dispersing agent to form a resin monomer dispersion, and this resin monomer dispersion comprises a suspension protective agent, a silicone-based antifoaming agent, a crosslinking agent, and a polymerization initiator. A step of suspending or emulsifying in the pure water containing to form a suspension or emulsion, and mixing the resin particle-containing aqueous dispersion and the suspension or emulsion to produce a mixed solution The liquid is subjected to suspension polymerization or emulsion polymerization, and the second resin contains a metal oxide having ultraviolet shielding properties on the entire surface of the core part made of the first resin or at one or more places on the surface. A first covering film or one or more first islands A step of by wearing the UV-shielding particles, characterized by having a.

According to the ultraviolet shielding particle of the present invention, a resin containing a metal oxide having ultraviolet shielding properties in the second resin on the entire surface of the core part made of the first resin or at one or more locations on the surface. Since the composition is attached to form the first coating film or the one or more first islands, the ultraviolet shielding effect can be enhanced as compared with the conventional ultraviolet shielding agent.
Since the ultraviolet shielding particles have a coating film or island-like material made of a metal oxide-containing resin composition attached to the surface of the core part, not to mention the water-in-oil type (W / O type), It can be blended into an oil-in-water (O / W type) cosmetic.

  A resin composition containing an organic ultraviolet absorber in the third resin is further adhered to the surface of the first coating film or the surface of the core member to which the first island-like material is adhered. If the second coating film or one or more second islands are used, the ultraviolet shielding effect can be further enhanced.

According to the ultraviolet shielding particle-containing dispersion of the present invention, since any one or two of the ultraviolet shielding particles of the present invention are dispersed in the dispersion medium, the ultraviolet shielding effect can be enhanced.
This dispersion containing ultraviolet light shielding particles can be blended into oil-in-water (O / W type) cosmetics as well as water-in-oil (W / O type).

  According to the cosmetic of the present invention, the ultraviolet shielding effect can be enhanced because it contains one or more selected from the group of the ultraviolet shielding particles of the present invention and the ultraviolet shielding dispersion of the present invention.

  According to the method for producing ultraviolet shielding particles of the present invention, the resin particle-containing aqueous dispersion preparation step, the resin monomer dispersion preparation step, the suspension or emulsion preparation step, and the resin particle-containing aqueous dispersion are suspended. Suspension polymerization or emulsion polymerization of a mixed liquid obtained by mixing a turbid liquid or an emulsified liquid, so that the entire surface of the core part made of the first resin or one or more portions of the surface is protected from ultraviolet rays in the second resin. The ultraviolet light shielding particles having an excellent ultraviolet light shielding effect. The ultraviolet light shielding particles having an ultraviolet light shielding effect are attached to the first coating film containing the metal oxide having the above or one or more first islands. Can be obtained.

It is sectional drawing which shows an example of the ultraviolet shielding particle of the 1st Embodiment of this invention. It is sectional drawing which shows another example of the ultraviolet shielding particle of the 1st Embodiment of this invention. It is sectional drawing which shows another example of the ultraviolet shielding particle of the 1st Embodiment of this invention. It is a perspective view which shows another example of the ultraviolet shielding particle of the 1st Embodiment of this invention. It is sectional drawing which shows an example of the ultraviolet-ray shielding particle of the 2nd Embodiment of this invention. It is sectional drawing which shows another example of the ultraviolet shielding particle of the 2nd Embodiment of this invention. It is sectional drawing which shows another example of the ultraviolet shielding particle of the 2nd Embodiment of this invention. It is a perspective view which shows another example of the ultraviolet shielding particle of the 2nd Embodiment of this invention. It is a scanning electron microscope (SEM) image which shows the ultraviolet-ray shielding particle of Example 1 of this invention. It is a scanning electron microscope (SEM) image which shows the ultraviolet-ray shielding particle of Example 1 of this invention. It is a transmission electron microscope (TEM) image which shows the ultraviolet shielding particle of Example 1 of this invention. It is a figure which shows the spectral transmittance | permeability of each coating film of Examples 1, 2 and Comparative Example 1 of this invention. It is a scanning electron microscope (SEM) image which shows the ultraviolet-ray shielding particle of Example 2 of this invention. It is a transmission electron microscope (TEM) image which shows the ultraviolet-ray shielding particle of Example 2 of this invention.

The form for implementing the manufacturing method of the ultraviolet shielding particle of this invention, the ultraviolet-ray shielding particle containing dispersion liquid, cosmetics, and an ultraviolet shielding particle is demonstrated.
The following embodiments are specifically described for better understanding of the gist of the invention, and do not limit the present invention unless otherwise specified.

[First Embodiment]
"Ultraviolet shielding particles"
The ultraviolet shielding particle of the present embodiment is a resin composition containing a metal oxide having ultraviolet shielding properties in the second resin on the entire surface of the core part made of the first resin or at one or more locations on the surface. This is a particle having an ultraviolet shielding property by attaching an object to form a first coating film or one or more first islands.

  FIG. 1 is a cross-sectional view showing an example of the ultraviolet shielding particles of the present embodiment. The ultraviolet shielding particles 1 are shielded against ultraviolet rays in the second resin over the entire surface of the core part 2 made of the first resin. It is the structure in which the coating film 3 which consists of a resin composition containing the metal oxide which has property was formed. The coating film 3 does not need to cover the entire surface of the core member 2, and may cover at least 1% of the surface of the core member 2.

  FIG. 2 is a cross-sectional view showing another example of the ultraviolet shielding particles of the present embodiment, and the ultraviolet shielding particles 11 are at one or more locations on the surface of the core member 12 made of the first resin (the cross section of FIG. 2). Then, islands 13 made of a resin composition containing a metal oxide having an ultraviolet shielding property are formed in the second resin (hereinafter sometimes referred to as island structures). The shape of the island 13 is appropriately selected from various shapes such as a circular shape, a hemispherical shape, a polyhedral shape, a plate shape, and a lens shape in addition to the elliptical cross section shown in FIG. Shape is preferred. The number of islands 13 is not particularly limited as long as the entire amount of all islands 13 can sufficiently exhibit the ultraviolet shielding function.

  FIG. 3 is a cross-sectional view showing still another example of the ultraviolet shielding particles of the present embodiment. The ultraviolet shielding particles 21 are formed on the surface of the core member 22 having an elliptical cross-sectional shape made of the first resin. An island-like material 23 made of a resin composition containing a metal oxide having an ultraviolet shielding property in the second resin is formed in more than four places (four places in the cross section of FIG. 3) (hereinafter referred to as an island-like structure). Sometimes called). The shape of the core member 22 is appropriately selected from various shapes such as a circular shape, a hemispherical shape, a polyhedral shape, and a lens shape in addition to the elliptical cross section shown in FIG. Further, the shape of the island-like object 23 is appropriately selected from various shapes such as a hemispherical shape, a polyhedral shape, a plate shape, and a lens shape in addition to the elliptical cross section shown in FIG. The number of islands 23 is not particularly limited as long as the whole amount of all islands 23 can sufficiently exhibit the ultraviolet shielding function.

  FIG. 4 is a perspective view showing still another example of the ultraviolet shielding particles of the present embodiment, and the ultraviolet shielding particles 31 are the surfaces of the core portion 32 made of a hexagonal plate-like body made of the first resin. In one or more places (two places in the plane of FIG. 4), islands 33 made of a resin composition containing a metal oxide having ultraviolet shielding properties in the second resin are formed (hereinafter referred to as islands). May be referred to as a structure). The shape of the core portion 32 is a hexagonal plate-like body shown in FIG. 4, a square plate-like body, a rectangular plate-like body, a polygonal plate-like body such as an octagon, a disc It is appropriately selected from various shapes such as a plate-like body. Further, the shape of the island-like object 33 is appropriately selected from various shapes such as a circular shape, a hemispherical shape, a polyhedral shape, a plate shape, and a lens shape in addition to the lens shape shown in FIG. The number of islands 33 is not particularly limited as long as the entire amount of all islands 33 can sufficiently exhibit the ultraviolet shielding function.

In these ultraviolet shielding particles, the average particle diameter is preferably 0.1 μm or more and 5 μm or less, more preferably 0.1 μm or more and 1 μm or less.
The “average particle diameter” of the ultraviolet shielding particles refers to a predetermined number, for example, 500 or 100, of the ultraviolet shielding particles, and the longest straight portion (maximum major diameter) of each of the ultraviolet shielding particles. It is a value obtained by measuring and averaging these measured values.
Here, the reason why the average particle diameter is limited to the above range is that when the average particle diameter is less than 0.1 μm, it is difficult to control the particle size and particle size distribution of the core material portion, and as a result, UV shielding is obtained. This is because the particle size and particle size distribution of the particles are also non-uniform.
On the other hand, when the average particle diameter exceeds 5 μm, the ultraviolet shielding particles themselves lose transparency, and the transparency is impaired when blended in cosmetics.

In these ultraviolet shielding particles, the total mass of the coating film or islands is preferably 1% by mass or more and 100% by mass or less, more preferably 5% by mass or more and 60% by mass with respect to the mass of the entire core part. % Or less.
Here, the reason why the total mass of the coating film or island-shaped material is within the above range with respect to the mass of the entire core material portion is that the total mass of the coating film or island-shaped material is the mass of the entire core material portion. On the other hand, when the content is less than 1% by mass, the content of the metal oxide having ultraviolet shielding properties in the ultraviolet shielding particles is reduced. Therefore, a cosmetic using the ultraviolet shielding particles has a sufficient ultraviolet shielding effect. It is necessary to significantly increase the content of the ultraviolet shielding particles in the cosmetic, and therefore it is not preferable because the content of the ultraviolet shielding particles cannot be kept low. On the other hand, if the total mass of the coating film or islands exceeds 100% by mass with respect to the total mass of the core material part, the particle size and particle size distribution of the core material part are effective for the particle size and particle size distribution of the ultraviolet shielding particles. This is not preferable because it may not be reflected in the image.

The size and shape of the core part made of the first resin are not particularly limited, but in the case of spherical particles, the average primary particle diameter is preferably 0.04 μm or more and 4.0 μm or less, more preferably 0.1 μm. It is above and 1.0 micrometer or less. In the case of lenticular particles or plate-like particles, the thickness is preferably 0.02 μm or more and 2.0 μm or less, the maximum major axis is preferably 0.2 μm or more and 5.0 μm or less, and more preferably the thickness is 0.2 μm or more and The maximum major axis is not less than 0.5 μm and not more than 3.0 μm.
The reason why the size and shape of the core part are in the above range is that when blended in a cosmetic, the transparency is high and the feeling of use is excellent.

The thickness of the coating layer and islands that partially or completely cover the core part is not particularly limited, but is preferably 0.01 μm or more and 0.7 μm or less, more preferably 0.01 μm or more and 0.5 μm or less. It is.
Here, when the thickness of the coating layer is less than 0.01 μm, the effect of the coating layer covering the core portion becomes insufficient, and the ultraviolet shielding effect in the coating layer may not be sufficiently exhibited, which is not preferable. On the other hand, if the thickness of the coating layer exceeds 0.7 μm, the coating layer and islands become too thick and the average particle size of the core material portion becomes relatively small. As a result, the ultraviolet absorbing effect of the ultraviolet shielding particles is reduced. This is not preferable because it may not be able to fully exhibit.

  The first resin constituting the core part is not particularly limited as long as it can be used as a raw material for cosmetics, but is not limited to (meth) acrylic resin, acrylic ester, methacrylic ester, acrylic styrene copolymer, acrylic A resin selected from the group of polyester copolymers, silicon acrylic copolymers, vinyl acetate resins, polyamide resins, epoxy resins, urethane resins, polyester resins, silicone resins, and polystyrene resins is preferably used. These resins may be used alone or in combination of two or more. Among these resins, (meth) acrylic resin is particularly preferable because of its excellent transparency.

Examples of such a first resin monomer include (meth) acrylic resin, acrylic ester, methacrylic ester, acrylic styrene copolymer, acrylamide copolymer, acrylic epoxy copolymer, and acrylic urethane copolymer. , Acrylic polyester copolymer, Silicon acrylic copolymer, Vinyl acetate resin, Polyamide resin, Epoxy resin, Urethane resin, Polyester resin, Silicone resin, etc. The above can be mixed and used.
Among these, a monomer of (meth) acrylic resin is preferable in that it is excellent in transparency.

  As a monomer of (meth) acrylic resin, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, acrylic acid Dodecyl, lauryl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, trifluoroethyl acrylate, tetrafluoropropyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate N-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, Lil and the like.

  Resin monomers that can be polymerized in combination with the above (meth) acrylic resin monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, o-ethylstyrene. , M-ethylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, pt-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn- Nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, vinyl acetate, vinyl propionate, vinyl benzoate, Vinyl butyrate, N-vinylpyrovinyl, vinylidene fluoride, tetrafluoroethylene, Sa hexafluoropropylene, butadiene, isoprene, and the like.

  These resin monomers may be used by polymerizing only one kind alone or in combination of two or more kinds. For example, when combining a monomer of a (meth) acrylic resin and another monomer, the content of the monomer of the (meth) acrylic resin in the resin monomer is preferably 10% by mass or more from the viewpoint of transparency. More preferably, it is 30% by mass or more.

  On the other hand, the second resin constituting the coating film or the island-shaped material is not particularly limited as long as it is a resin that has a high transparency of the monomer polymer of the second resin and can be used as a raw material for cosmetics. . Since the second resin can use the same monomer as the monomer of the first resin described above, description thereof is omitted.

  Although the combination of 1st resin and 2nd resin is not specifically limited, It is preferable that it is a combination with good adhesiveness, such as setting it as (meth) acryl resin together.

As the metal oxide having ultraviolet shielding properties contained in the second resin, one or more selected from the group of zinc oxide, titanium oxide, cerium oxide, and iron oxide are preferably used.
The average primary particle diameter of the metal oxide is preferably 0.003 μm or more and 0.1 μm or less, more preferably 0.01 μm or more and 0.05 μm or less, and further preferably 0.02 μm or more and 0.04 μm or less. .
Here, when the average primary particle diameter of the metal oxide is less than 0.003 μm, the degree of crystallinity is lowered and the ultraviolet shielding function is not exhibited, which is not preferable. On the other hand, when the average primary particle diameter exceeds 0.1 μm, Since the scattering coefficient of particles with respect to visible light is increased, the transparency is remarkably lowered, and as a result, the light transmittance with respect to visible light is lowered and the transparency is deteriorated.

  The metal oxide may be one that is surface-treated with one or more selected from the group consisting of silica, alumina, and organopolysiloxane. When the metal oxide is surface-treated with one or more selected from the group consisting of silica, alumina and organopolysiloxane, the metal ions constituting the metal oxide are difficult to flow out because the surface is covered. Therefore, the surface activity of the metal oxide is more controlled, which is preferable.

The content of the metal oxide in the second resin is preferably 1% by mass to 80% by mass, more preferably 5% by mass to 70% by mass, and still more preferably 10% by mass to 60% by mass. % Or less.
Here, if the content of the metal oxide in the resin is less than 1% by mass, the amount of the metal oxide is too small, and the ultraviolet shielding function of the metal oxide cannot be sufficiently exhibited, which is not preferable. On the other hand, when the content exceeds 80% by mass, the amount of the metal oxide is relatively high with respect to the resin. As a result, the dispersibility of the metal oxide in the resin is lowered, and the uniformity of the composition is increased. Since it will be damaged, it is not preferable.

"Production method of UV shielding particles"
The method for producing ultraviolet shielding particles of the present embodiment includes a resin particle-containing aqueous dispersion preparation step in which resin particles that form a core part made of a first resin are dispersed in water to form a resin particle-containing aqueous dispersion, A resin monomer dispersion preparation step in which a metal oxide having ultraviolet shielding properties is dispersed in a resin monomer of a second resin containing a dispersant to form a resin monomer dispersion, and this resin monomer dispersion is used as a suspension protective agent. , A suspension or emulsion preparation step for suspending or emulsifying in pure water containing a silicone-based antifoaming agent, a crosslinking agent and a polymerization initiator to form a suspension or emulsion, and the resin particle-containing aqueous dispersion And the suspension or emulsion are mixed to prepare a mixed solution, and the mixed solution is subjected to suspension polymerization or emulsion polymerization so that the entire surface of the core part made of the first resin or one place on the surface In the above, UV shielding in the second resin Having a UV-shielding particle preparation step of first covering layer or one or more by attaching the first island-like material to ultraviolet light shielding particles comprising a metal oxide having a.

Next, the manufacturing method of the ultraviolet shielding particle of this embodiment is demonstrated in detail for every process.
(Resin particle-containing aqueous dispersion preparation process)
This is a step of dispersing resin particles that form a core part made of the first resin in water to obtain a resin particle-containing aqueous dispersion.
The production of the resin particle-containing aqueous dispersion is not particularly limited as long as the resin particles serving as the core part can be dispersed in water. For example, the resin particle used as a core material part and water are mixed, and the method etc. which are made to disperse | distribute with a dispersion apparatus are mentioned. Moreover, you may add additives, such as a dispersing agent, as needed.

  The dispersion device used in this step is not particularly limited as long as it can provide sufficient dispersion energy to the dispersion, and examples thereof include a ball mill, a sand mill, an ultrasonic disperser, and a homogenizer. It is done.

  In order to manufacture the core part made of the first resin, a method capable of forming the above-described resin into a desired size and shape may be used, and there is no particular limitation. Moreover, you may use the resin particle of the commercial item which consists of resin mentioned above.

Examples of the method for producing the core material part include a method in which a resin monomer is emulsified or suspended and polymerized.
Examples of commercially available resin particles include acrylic beads (manufactured by Soken Chemical Co., Ltd.).

(Resin monomer dispersion preparation process)
In this step, metal oxide particles having ultraviolet shielding properties are dispersed in a monomer of a second resin containing a dispersant to form a resin monomer dispersion.
Since the metal oxide particles having the ultraviolet shielding property and the monomer of the second resin are exactly the same as the above-described metal oxide particles and the monomer of the first resin, description thereof is omitted here.

As the dispersant, a dispersant having high affinity with the monomer of the second resin and high hydrophobicity is preferable. That is, the dispersant coats the metal oxide to promote the dispersion of the second resin with respect to the monomer, and at the same time, the metal oxide particles are almost monodispersed in a relatively short time, The average dispersed particle size is 0.003 μm or more and 0.1 μm or less.
In addition, since the dispersant imparts hydrophobicity to the metal oxide, the metal oxide does not go out of the polymer and helps to be taken into the resin without shifting to the aqueous phase.

  Examples of such a dispersant include carboxylic acids such as sodium carboxymethyl cellulose or salts thereof, sulfonic acids such as sodium alkanesulfonate or salts thereof, sulfate esters such as polyoxyethylene nonylphenyl ether sodium sulfate or salts thereof, Examples thereof include phosphoric acid esters such as oxyethylene alkylphenyl ether phosphoric acid and polyoxyethylene alkyl ether phosphoric acid or salts thereof, and phosphonic acids such as sodium lauryl phosphate or salts thereof. These may be used alone or in combination of two or more.

In particular, when the ultraviolet shielding particles of the present embodiment are used in cosmetics, these dispersants must be recognized as raw materials for cosmetics at the same time.
The addition ratio of the dispersant to the metal oxide is preferably 1% by mass or more and 50% by mass or less. If the addition rate is less than 1% by mass, it is too small to cover the surface of the metal oxide, so that a sufficient dispersion state of the metal oxide cannot be obtained. Even if it raises, dispersibility cannot be improved further and a dispersing agent becomes useless.

The dispersing device used is not particularly limited as long as it can impart sufficient dispersion energy to the dispersion system, and examples thereof include a ball mill, a sand mill, an ultrasonic disperser, and a homogenizer.
The dispersion time is preferably about 30 minutes to 3 hours, but an appropriate time may be selected in consideration of the quality of the dispersion state and the manufacturing cost.

The average dispersed particle size of the metal oxide particles in this resin monomer dispersion is preferably 0.003 μm or more and 0.1 μm or less.
Here, when the average dispersed particle size in the resin monomer dispersion of the metal oxide particles exceeds 0.1 μm, the scattering coefficient of the ultraviolet shielding particles with respect to visible light increases, and thus the transparency decreases. As a result, the transparency is remarkably lowered, and in some cases, there is a risk of devitrification.
As described above, a resin monomer dispersion having an average dispersed particle diameter of metal oxide particles of 0.003 μm or more and 0.1 μm or less can be obtained.

(Suspension or emulsion preparation process)
The above resin monomer dispersion is suspended or emulsified in pure water containing a suspension protective agent, a silicone-based antifoaming agent, a crosslinking agent, and a polymerization initiator, and the dispersed particle diameter is 0.05 μm or more and 5 μm or less. It is a process of making a turbid liquid or an emulsified liquid.

Suspension protectants include nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkylphenyl ethers, and anionic surfactants such as alkylbenzene sulfonates, alkyl sulfate esters, and alkylphenyl sulfate esters. Among these, an anionic surfactant is preferable, and an alkyl benzene sulfonate is preferable as the anionic surfactant.
The addition amount of the suspension protective agent is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.1% by mass or more and 2% by mass or less with respect to the resin monomer dispersion.

Examples of the silicone antifoaming agent include an oil type, an oil compound type, a solution type, a powder type, a solid type, an emulsion type, and a self-emulsifying type. Among these, an oil compound type is preferable.
The addition amount of the silicone-based antifoaming agent is preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.1% by mass or more and 1% by mass or less with respect to the resin monomer dispersion. is there.

The crosslinking agent is not particularly limited as long as it is a monomer having two or more unsaturated double bonds, but is not limited to a polyfunctional vinyl monomer or a polyfunctional (meth) acrylic acid ester derivative. Etc. can be appropriately selected and used.
Specific examples of the crosslinking agent include divinylbenzene, divinylbiphenyl, divinylnaphthalene, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, and (poly) tetramethylene glycol di (meth). (Poly) alkylene glycol type | system | group di (meth) acrylates, such as acrylate, are mentioned.

  1,6-hexanediol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, 2,4-diethyl-1,5-pentanediol di (meth) acrylate, butylethylpropanediol Examples include alkanediol di (meth) acrylates such as di (meth) acrylate, 3-methyl-1,7-octanediol di (meth) acrylate, and 2-methyl-1,8-octanediol di (meth) acrylate. .

  Also, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, ethoxylated cyclohexanedi Methanol di (meth) acrylate, ethoxylated bisphenol A di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, 1,1,1-trishydroxymethylethane Di (meth) acrylate, 1,1,1-trishydroxymethylethane tri (meth) acrylate, 1,1,1-trishydroxymethylpropane triacrylate, diary Phthalate and its isomers, triallyl isocyanurate and derivatives thereof.

Among these crosslinking agents, (poly) ethylene glycol di (meth) acrylate is particularly preferable.
The addition amount of the crosslinking agent is preferably 0.1% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 10% by mass or less with respect to the resin monomer dispersion.

  Polymerization initiators include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, benzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide, and other organic peroxides. And azo initiators such as azobisdiisobutyronitrile and 2,2-azobis (2-amidinopropane) dihydrochloride.

Among these polymerization initiators, persulfates such as potassium persulfate and ammonium persulfate are particularly preferable.
The addition amount of the polymerization initiator is preferably 0.01% by mass or more and 1% by mass or less, and more preferably 0.05% by mass or more and 0.5% by mass or less with respect to the resin monomer dispersion.

  The pure water is not particularly limited as long as it is pure water generally used in cosmetics. Instead of pure water, ion-exchanged water, distilled water, purified water, ultrapure water, natural water, Alkaline ion water, deep layer water, or the like may be used.

(Ultraviolet shielding particle production process)
The resin particle-containing aqueous dispersion and the suspension or emulsion are mixed to prepare a mixture, and the mixture is subjected to suspension polymerization or emulsion polymerization to obtain the surface of the core portion made of the first resin. The first resin film containing one or more first island-like substances containing a metal oxide having an ultraviolet shielding property in the second resin is adhered to the whole or at least one place on the surface, and ultraviolet rays are attached. This is a step of forming shielding particles.

  The mixing ratio of the resin particle-containing aqueous dispersion and the suspension or emulsion may be appropriately adjusted so as to obtain a desired ultraviolet shielding performance. The content is preferably 5% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and further preferably 20% by mass or more and 40% by mass or less.

As a method for suspension polymerization or emulsion polymerization, a method of starting the polymerization by heating the above mixed solution in a nitrogen atmosphere and in the presence of a polymerization initiator while stirring is preferable.
The polymerization initiation temperature is preferably 50 ° C. or more and 80 ° C. or less. The polymerization time while maintaining this temperature is preferably about 1 to 5 hours, and the time when the unreacted residual monomer is minimized, the polymerization state, and the production cost are set appropriately. Good.
Thereafter, the polymerization reaction is stopped by ice cooling or natural cooling to stop the polymerization reaction, whereby a polymerization reaction stop solution containing ultraviolet shielding particles can be obtained.

  In this suspension polymerization or emulsion polymerization, the average particle size of the obtained ultraviolet shielding particles is set to 0.00 by limiting the contents of these suspension protective agent, silicone antifoaming agent and polymerization initiator to the above ranges. It can be controlled to be not less than 05 μm and not more than 5 μm.

Next, the obtained suspension polymer or emulsion polymer (hereinafter sometimes simply referred to as “polymer”) is washed with pure water. In this washing process, in order to improve the washing efficiency, washing may be performed using a hydrophilic organic solvent such as alcohol before washing with pure water. Thereby, the monomer, polymerization initiator, and surfactant remaining in the polymer are removed.
The alcohol is not particularly limited as long as it is soluble in pure water and can be easily removed by washing, and examples thereof include ethanol and 2-propanol. 2-propanol is particularly preferable.

The method for removing alcohol, residual monomer, and the like after washing is not particularly limited as long as alcohol and residual monomer can be efficiently removed, but is not limited to pressure filtration, suction filtration, filter press, centrifugal separation, ultrafiltration. Decantation and the like are preferable.
After the washing is completed, the obtained polymer is dried at 80 ° C. to 100 ° C. to remove pure water remaining in the polymer. The drying method is not particularly limited as long as it is a method capable of removing alcohol and pure water, and examples thereof include drying in atmospheric pressure and vacuum drying.

Next, the dried polymer is crushed. The crushing method is not particularly limited as long as it can crush each particle, and examples thereof include a pin mill, a hammer mill, a jet mill, and an impeller mill.
As described above, the ultraviolet shielding particles of the present embodiment can be obtained.
The ultraviolet shielding particles obtained in this manner can be subjected to a crushing step to crush each particle aggregated by drying and improve the feeling of use when used in cosmetics.

  As described above, according to the ultraviolet shielding particles of the present embodiment, the entire surface of the core part made of the first resin or one or more places on the surface is oxidized with metal that has ultraviolet shielding properties in the second resin. Since the resin composition containing the product is adhered to form a coating film or one or more islands, the ultraviolet shielding effect can be enhanced.

Further, the ultraviolet shielding particles of the present embodiment are not only water-in-oil type (W / O type), but also oil-in-water type (O / W type), lotion and sunscreen gel, which have been difficult to formulate conventionally. It can mix | blend with water-based cosmetics, such as. Therefore, the freedom degree of cosmetics prescription can be raised.
Further, when the average particle size of the ultraviolet shielding particles is 0.1 μm or more and 5 μm or less, even when used for cosmetics, there is no rough feeling and the feeling of use is excellent.

  According to the method for producing ultraviolet shielding particles of the present embodiment, ultraviolet shielding particles having an excellent ultraviolet shielding effect can be obtained.

[Second Embodiment]
"Ultraviolet shielding particles"
The ultraviolet shielding particle of the present embodiment is a resin composition containing a metal oxide having ultraviolet shielding properties in the second resin on the entire surface of the core part made of the first resin or at one or more locations on the surface. A first coating film or one or more first island-shaped objects are attached by attaching an object, and the surface of the first coating film or the surface of the core portion to which the first island-shaped object is adhered In addition, a particle having ultraviolet shielding properties in which a resin composition containing an organic ultraviolet absorber in a third resin is adhered to form a second coating film or one or more second islands. It is.

  In the ultraviolet shielding particles of the present embodiment, a resin composition containing a metal oxide having ultraviolet shielding properties in the second resin over the entire surface of the core portion made of the first resin or at one or more locations on the surface. Since the first coating film or the one or more first island-shaped objects are adhered to the object, it is exactly the same as the ultraviolet shielding particles of the first embodiment, and thus the description thereof is omitted.

  In the ultraviolet shielding particles of the present embodiment, the resin composition containing the organic ultraviolet absorber in the third resin is on the entire surface of the ultraviolet shielding particles of the first embodiment or at one or more locations on the surface. Any structure may be used as long as it is attached as a coating film or one or more islands, and is not particularly limited.

  As described above, the coating film made of the third resin containing the organic ultraviolet absorber or one or more islands on the entire surface of the ultraviolet shielding particles of the first embodiment or at one or more locations on the surface. By attaching an object, the ultraviolet shielding performance can be further enhanced by the synergistic effect of the metal oxide in the ultraviolet shielding particles and the organic ultraviolet absorbent in the third resin. Therefore, a further excellent ultraviolet shielding effect can be obtained.

FIG. 5 is a cross-sectional view showing an example of the ultraviolet shielding particle of the present embodiment. The ultraviolet shielding particle 41 is formed by metal oxidation in the second resin on the entire surface of the core part 2 made of the first resin. A coating film 42 made of a resin composition containing an organic ultraviolet absorber in the third resin is formed on the entire surface of the ultraviolet shielding particles 1 on which the coating film 3 made of a resin composition containing the product is formed. It is a formed structure. The coating film 42 is not required to cover the entire surface of the ultraviolet shielding particles 1 as long as it can sufficiently exhibit the absorption performance of the organic ultraviolet absorber. Therefore, it is sufficient to cover at least 1% of the entire surface of the ultraviolet shielding particles 1. The coating film 3 may be a partial coating.
As for the shape of the core member 2, various shapes such as an elliptical shape, a polyhedral shape, and a lens shape can be selected in addition to the circular cross-sectional shape shown in FIG. 5, but the circular shape is preferable among them.

  FIG. 6 is a cross-sectional view showing another example of the ultraviolet shielding particles of the present embodiment, and the ultraviolet shielding particles 51 are formed on the entire surface of the core part 2 made of the first resin in the second resin. An organic ultraviolet absorber is added to the third resin at one or more locations (a plurality of locations in FIG. 6) on the surface of the ultraviolet shielding particles 1 on which the coating film 3 made of a resin composition containing a metal oxide is formed. An island-shaped object 52 made of the contained resin composition is formed (hereinafter sometimes referred to as an island-shaped structure). The shape of the island-like object 52 is appropriately selected from various shapes such as an elliptical shape, a hemispherical shape, a polyhedral shape, a plate shape, and a lens shape in addition to the circular shape shown in FIG. The number of the islands 52 is not particularly limited as long as the entire amount of all the islands 52 can sufficiently exhibit the ultraviolet absorption performance. The coating film 3 may be a partial coating.

  FIG. 7 is a cross-sectional view showing still another example of the ultraviolet shielding particles of the present embodiment, and the ultraviolet shielding particles 61 are at one or more locations on the surface of the core member 12 made of the first resin (in FIG. 7). The organic ultraviolet absorber in the third resin is formed on the entire surface of the ultraviolet shielding particles 11 in which the islands 13 made of the resin composition containing the metal oxide in the second resin are formed at a plurality of locations. This is a structure in which a coating film 62 made of a resin composition containing is formed. The coating film 62 only needs to be able to sufficiently exhibit the ultraviolet absorption performance, and as shown in FIG. 7, it is not necessary to completely embed the island-like object 13, and is formed as a thin film on the outer periphery of the island-like object 13. May be. In short, it is not necessary to cover the entire surface of the ultraviolet shielding particles 11. Therefore, it is sufficient to cover at least 1% of the entire surface of the ultraviolet shielding particles 11.

  FIG. 8 is a cross-sectional view showing still another example of the ultraviolet shielding particles of the present embodiment, and the ultraviolet shielding particles 71 are at one or more locations on the surface of the core 12 made of the first resin (in FIG. 8). The organic resin is contained in the third resin at one or more places on the surface of the ultraviolet shielding particles 11 in which the islands 13 made of the resin composition containing the metal oxide in the second resin are formed at a plurality of places. An island-like object 72 made of a resin composition containing an ultraviolet absorber is formed (hereinafter sometimes referred to as an island-like structure). The island 72 may be attached to the core member 12, may be attached to the island 13, or may be attached to both the core member 12 and the island 13. In other words, the island-like object 72 may be attached anywhere as long as it is the surface of the ultraviolet shielding particle 11.

  The shape of the island 72 is appropriately selected from various shapes such as a circular shape, a hemispherical shape, a polyhedral shape, a plate shape, and a lens shape in addition to an elliptical cross section shown in FIG. Further, the number of the islands 72 is not particularly limited as long as the entire amount of all the islands 72 can sufficiently exhibit the ultraviolet absorption performance.

As the third resin, since the same resin as the second resin described above can be used, description thereof is omitted.
The organic ultraviolet absorber contained in the third resin may be appropriately selected depending on the application. For example, dibenzoylmethane compounds, benzophenone derivatives, paraaminobenzoic acid derivatives, methoxycinnamic acid derivatives, salicylic acid derivatives, etc. Is mentioned.
Of these, dibenzoylmethane compounds are preferred. These organic ultraviolet absorbers may be used alone or in combination of two or more.

The combination of the first resin, the second resin, and the third resin is not particularly limited, but is preferably a combination with good adhesion such as a (meth) acrylic resin.
Further, a resin composition containing one or both of an organic ultraviolet absorber and a metal oxide on the surface of the ultraviolet shielding particles 41 to 71 as a single-layer or multiple-layer coating film, or It may be attached as one or more islands.

"Production method of UV shielding particles"
The manufacturing method of the ultraviolet shielding particles of the present embodiment includes the first coating film surface of the ultraviolet shielding particles of the first embodiment described above or the surface of the core part to which the first island-like material is attached. A coating film or island-like material attaching step in which a resin composition containing an organic ultraviolet absorber is attached to the resin 3 to form a second coating film or one or more second island-like materials Have

  That is, the method for producing the ultraviolet shielding particles of the present embodiment is a method for preparing a resin monomer solution by dissolving an organic ultraviolet absorber in a resin monomer and then adding a dispersant to the solution to obtain a resin monomer solution. A step, a second suspension or emulsion preparation step in which the resin monomer solution is suspended or emulsified in pure water containing a polymerization initiator to form a second suspension or emulsion; The polymerization reaction stop solution obtained in the course of the manufacturing method of the ultraviolet shielding particles of the first embodiment and the second suspension or emulsion described above are mixed to form a mixed solution, and this mixed solution is suspended. And performing polymerization or emulsion polymerization to obtain the ultraviolet shielding particles of the present embodiment.

(Resin monomer solution preparation process)
In this step, an organic ultraviolet absorber is dissolved in a resin monomer, and then a dispersant is added and mixed to obtain a resin monomer solution.
Since the organic ultraviolet absorber and the resin monomer are exactly the same as the organic ultraviolet absorber and the first resin monomer described above, the description thereof is omitted.

The dispersant is mixed in an amount of 1% by mass to 50% by mass with respect to the total mass of the resin monomer solution. Since the dispersant is exactly the same as the dispersant used in the above-described resin monomer dispersion preparation step, description thereof is omitted.
Here, the reason why the dispersant is added in an amount of 1% by mass or more and 50% by mass or less is that when the addition rate is less than 1% by mass, the emulsion film strength of the suspension or emulsion described later does not increase, and as a result, This is because the polymerization efficiency of the turbid polymerization or the emulsion polymerization is lowered. On the other hand, if it exceeds 50% by mass, further improvement of the polymerization efficiency cannot be expected, and the dispersant is wasted.
By the above, the resin monomer solution containing an organic ultraviolet absorber can be obtained.

(Coating film or island attachment process)
The resin monomer solution is suspended or emulsified in pure water containing 0.01% by mass or more and 1% by mass or less of a polymerization initiator with respect to the total mass of the resin monomer solution. Emulsified.
Since these polymerization initiators and pure water are exactly the same as the above-mentioned “polymerization initiator” and “pure water”, description thereof is omitted.

This suspension or emulsion is mixed with the polymerization reaction termination liquid containing the ultraviolet shielding particles, and then polymerized, washed, in the same manner as in the ultraviolet shielding particle production process of the first embodiment described above. The ultraviolet shielding particles of this embodiment can be obtained by drying and crushing.
The mixing ratio of the suspension or emulsion and the polymerization reaction stop solution is preferably such that the organic ultraviolet absorber and the metal oxide are in a mass ratio of 1: 9 to 5: 5. .
By mixing in the above range, a synergistic effect of the ultraviolet shielding performance of the organic ultraviolet absorber and the metal oxide can be obtained.

  As described above, according to the ultraviolet shielding particles of the present embodiment, the entire surface of the core part made of the first resin or one or more places on the surface is oxidized with metal that has ultraviolet shielding properties in the second resin. A resin composition containing a product is adhered to form a first coating film or one or more first island-shaped materials, and the surface of the first coating film or the first island-shaped material. A second coating film or at least one second island-shaped material is obtained by adhering a resin composition containing an organic ultraviolet absorber in a third resin to the surface of the core material portion to which the material has adhered. Therefore, the ultraviolet shielding effect can be further enhanced.

  According to the method for producing ultraviolet shielding particles of the present embodiment, ultraviolet shielding particles having an excellent ultraviolet shielding effect can be obtained.

[Third Embodiment]
The ultraviolet shielding dispersion of this embodiment is a dispersion in which one or two of the ultraviolet shielding particles of the first embodiment and the ultraviolet shielding particles of the second embodiment are dispersed in a dispersion medium. .

  Such a dispersion medium may be any solvent that can disperse the above-described ultraviolet shielding particles. In addition to water, for example, alcohols such as methanol, ethanol, 2-propanol, butanol, octanol, ethyl acetate, Esters such as butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, γ-butyrolactone, diethyl ether, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), ethylene Glycol monobutyl ether (butyl cellosolve), ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetone, methyl ethyl , Ketones such as methyl isobutyl ketone, acetylacetone, cyclohexanone, aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, amides such as dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethylpolysiloxane , Chain polysiloxanes such as methylphenyl polysiloxane, diphenyl polysiloxane, cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexanesiloxane, amino-modified polysiloxane, polyether-modified polysiloxane Modified polysiloxanes such as alkyl-modified polysiloxane and fluorine-modified polysiloxane are preferably used, and only one kind or two or more kinds of these solvents are mixed. Can be used.

The content of the ultraviolet shielding particles in the ultraviolet shielding dispersion is 1% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 70% by mass or less, and further preferably 30% by mass or more and 60% by mass or less. It is.
Here, when the content of the ultraviolet shielding particles is less than 1% by mass, the amount of the metal oxide is too small, and the dispersion cannot sufficiently exhibit the ultraviolet shielding function. This is not preferable because the material design during production becomes extremely difficult. On the other hand, when the content exceeds 80% by mass, the amount of the ultraviolet shielding particles in the dispersion is relatively high. As a result, the dispersibility of the ultraviolet shielding particles in the dispersion is lowered, and the uniformity of the composition is increased. Since it will be damaged, it is not preferable.

This dispersion is prepared by mixing the above-described ultraviolet shielding particles with a dispersion medium, and if necessary, mixing a dispersant and a water-soluble binder, and then mixing the mixture with a sand mill, a bead mill using zirconia beads, a ball mill, a homogenizer, or the like. It can be obtained by carrying out a dispersion treatment using a disperser or a mixer and dispersing the ultraviolet shielding agent in a dispersion medium.
The time required for the dispersion treatment is not particularly limited as long as it is sufficient for the ultraviolet shielding particles to be dispersed in the dispersion medium.

  Here, as specific examples of this ultraviolet shielding dispersion, an ultraviolet shielding silicone dispersion in which ultraviolet shielding particles are dispersed in a silicone resin and an ultraviolet shielding aqueous dispersion in which ultraviolet shielding particles are dispersed in water will be described.

"Ultraviolet shielding silicone dispersion"
This ultraviolet shielding silicone dispersion is an ultraviolet shielding silicone dispersion obtained by dispersing the above ultraviolet shielding particles in silicone, and the content of the ultraviolet shielding particles is 1% by mass or more and 80% by mass or less, more preferably 20%. It is a silicone-based dispersion containing not less than 70% by mass and not more than 70% by mass, more preferably not less than 30% by mass and not more than 60% by mass.

The silicone is not particularly limited as long as it is a cyclic silicone having a structural skeleton represented by the formula (1) or a linear silicone.
Examples of such silicone include dimethylpolysiloxane, methylphenylpolysiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylpentasiloxane, and methyltrimethicone.

In formula (1), X is preferably in the range of 1 to 2000. It is preferable that X is in the above range because mixing with the ultraviolet shielding agent of the present embodiment is facilitated.

The dispersant is not particularly limited as long as it can disperse the ultraviolet shielding particles in the silicone, and examples thereof include polyether-modified silicone, polyglycerin-modified silicone, amino-modified silicone, phenyl-modified silicone, alkyl-modified silicone, Examples thereof include carbinol-modified silicone and dimethyl silicone.
The dispersant is preferably in the range of 1% by mass to 50% by mass with respect to the total mass of the ultraviolet shielding particles.

Further, natural oil, humectant, thickener, fragrance, preservative and the like may be further mixed with the dispersion obtained by dispersing the silicone and the dispersant with a sand mill or a homogenizer.
By adjusting within the above range, even if this ultraviolet shielding silicone dispersion is used alone or mixed directly with cosmetics, transparency can be sufficiently secured when spread and applied to the skin. it can.

"Ultraviolet shielding aqueous dispersion"
This ultraviolet shielding aqueous dispersion is an ultraviolet shielding aqueous dispersion in which the above ultraviolet shielding particles are dispersed in an aqueous dispersion medium containing alcohols, and the content of the ultraviolet shielding particles is 1% by mass or more and 80% by mass. Or less, more preferably 20% by mass or more and 70% by mass or less, further preferably 30% by mass or more and 60% by mass or less, and an aqueous dispersion containing 5% by mass or more and 20% by mass or less of alcohols. It is.

  In this aqueous dispersion, the water-soluble polymer is further added in an amount of 0.001% by mass to 10% by mass, more preferably 0.005% by mass and 5% by mass, and still more preferably 0.01% by mass and more. It is good also as containing 3 mass% or less. In this case, it is necessary to adjust the content of each component so that the total content of each component of the ultraviolet shielding particles, alcohols and water-soluble polymer does not exceed 100% by mass.

  Examples of alcohols include monohydric alcohols having 1 to 6 carbon atoms such as ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, glycerin, 1,3-butylene glycol, propylene glycol, and sorbitol, or polyvalent ones. Examples include alcohols, and among them, monohydric alcohols, particularly ethanol is preferable.

When this aqueous dispersion does not contain a water-soluble polymer, the content of alcohol is preferably 5% by mass or more and 20% by mass or less, more preferably 10% by mass or more and 20% by mass or less.
In particular, when the alcohol content is 10% by mass or more and 20% by mass or less, the dispersibility and the temporal stability of the ultraviolet shielding particles in the aqueous dispersion can be improved.

Further, when the aqueous dispersion contains a water-soluble polymer, the water-soluble polymer is not particularly limited as long as it can be used for cosmetics, and is not particularly limited, but includes gum arabic, sodium alginate, casein, carrageenan, and galactan. , Carboxyvinyl polymer, carboxymethylcellulose, sodium carboxymethylcellulose, carboxymethyl starch, agar, xanthan gum, quince seed, guar gum, collagen, gelatin, cellulose, dextran, dextrin, tragacanth gum, hydroxyethylcellulose, hydroxypropylcellulose, sodium hyaluronate pectin, pullulan , Methyl cellulose, methyl hydroxypropyl cellulose and the like. These water-soluble polymers may be used alone or in combination of two or more.
The water-soluble polymer has a role as a dispersant and a viscosity modifier, and when added, the dispersibility and the temporal stability of the ultraviolet shielding particles in the aqueous dispersion are also improved.

When the aqueous dispersion contains a water-soluble polymer, the content of alcohol is preferably 5% by mass or more and 20% by mass or less, more preferably 15% by mass or more and 20% by mass or less.
Here, the reason why the alcohol content when the aqueous dispersion contains a water-soluble polymer is 5 mass% or more and 20 mass% or less is that the content of alcohol is less than 5 mass%. Since it is too little, the water-soluble polymer cannot uniformly infiltrate into alcohols and will swell non-uniformly with moisture, and as a result, the dispersibility of the ultraviolet shielding particles decreases, making handling difficult, Furthermore, the stability with time of the aqueous dispersion decreases, which is not preferable. On the other hand, if the content exceeds 20% by mass, the viscosity of the entire aqueous dispersion is increased, the dispersion stability of the ultraviolet shielding particles is lowered, and the aging stability of the aqueous dispersion is also lowered.

In this ultraviolet shielding aqueous dispersion, the above ultraviolet shielding agent is mixed in a solvent (dispersion medium) containing alcohols or a mixture (dispersion medium) containing alcohols and a water-soluble polymer, and then water is mixed. Can be obtained by dispersing them.
The amount of water may be appropriately adjusted, but a range of 15% by mass to 94% by mass is preferable.
By adjusting the amount of this water to the above range, it can be used alone or mixed with cosmetics, and an ultraviolet shielding water system that can sufficiently ensure transparency when applied by spreading on the skin. A dispersion is obtained.

  As described above, according to the ultraviolet shielding dispersion of this embodiment, one or two of the ultraviolet shielding particles of the first embodiment and the ultraviolet shielding particles of the second embodiment are used as the dispersion medium. Since it is dispersed inside, it is possible to improve the ultraviolet shielding property.

[Fourth Embodiment]
The cosmetic of the present embodiment is one or two selected from the group consisting of the ultraviolet shielding particles of the first embodiment, the ultraviolet shielding particles of the second embodiment, and the ultraviolet shielding dispersion of the third embodiment. Cosmetics containing the above.
This cosmetic contains one or both of ultraviolet shielding particles and ultraviolet shielding dispersion liquid in an amount of 1% by mass or more and 60% by mass or less in terms of ultraviolet shielding particles, so that there is no fear of whitening and sufficient transparency is obtained. In addition, there is no roughness or the like, and the feeling of use is excellent.

  This cosmetic can be obtained by conventionally blending one or both of the above-described ultraviolet shielding particles and ultraviolet shielding dispersion liquid into an emulsion, cream, foundation, lipstick, blusher, eye shadow, and the like.

  Furthermore, by blending either or both of the above-described UV-shielding particles and UV-shielding dispersions into water-based cosmetics such as lotions and sunscreen gels that have been difficult to formulate conventionally, for example, metal oxidation When zinc oxide is used as a product, elution of zinc can be suppressed, and a water-based cosmetic excellent in ultraviolet shielding property, transparency, and feeling of use can be obtained.

  By using this cosmetic as a component of cosmetics, it is possible to provide various cosmetics such as skin care cosmetics, makeup cosmetics, body care cosmetics and the like excellent in ultraviolet shielding properties, transparency, and feeling of use. In particular, it is suitable for whitening skin care cosmetics that require UV shielding, base makeup for makeup cosmetics, sunscreens for body care cosmetics, and the like.

  As described above, according to the cosmetic material of the present embodiment, from the group of the ultraviolet shielding particles of the first embodiment, the ultraviolet shielding particles of the second embodiment, and the ultraviolet shielding dispersion liquid of the third embodiment. Since 1 type or 2 types or more selected were contained, the ultraviolet-ray shielding effect can be improved.

  Furthermore, by using the cosmetic of the present embodiment as a cosmetic ingredient, various cosmetics such as skin care cosmetics, makeup cosmetics, body care cosmetics and the like excellent in ultraviolet shielding ability, transparency, usability and safety are provided. Can do. In particular, when used for whitening skin care cosmetics that require UV shielding ability, base makeup for makeup cosmetics, sunscreens for body care cosmetics, etc., cosmetics with excellent UV shielding ability, transparency and usability Can be provided.

In addition, the ultraviolet shielding particles of the first embodiment, the ultraviolet shielding particles of the second embodiment, and the ultraviolet shielding dispersion of the third embodiment can be diverted to weather resistant paints that require an ultraviolet shielding function. Can do.
In addition, when used in fields other than cosmetics, there are many cases where the feeling of roughness and feeling of use, which are regarded as important in cosmetics, are not so much of a problem. The degree of freedom can be further increased.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited by these Examples.

[Example 1]
"Production of UV shielding particles"
Acrylic particle dispersion was prepared by adding 30 parts by mass of acrylic particles MP-2200 (average primary particle size: 0.3 μm, manufactured by Soken Chemical Co., Ltd.) to 70 parts by mass of pure water and using a homogenizer.

  50 parts by mass of zinc oxide (average primary particle size: 0.02 μm, manufactured by Sumitomo Osaka Cement), 47 parts by mass of methyl methacrylate and 3 parts by mass of a phosphoric acid ester type surfactant are mixed and dispersed for 2 hours using a sand mill. The monomer (MMA) dispersion liquid in which the zinc oxide fine particles were dispersed in methyl methacrylate was obtained.

  Next, 30 parts by mass of the monomer (MMA) dispersion obtained, 64.9 parts by mass of pure water, 0.9 parts by mass of sodium dodecylbenzenesulfonate, 3.9 parts by mass of ethylene glycol dimethacrylate, 0 3 parts by mass were mixed and emulsified using a homogenizer to prepare an emulsion.

  Next, 60 parts by mass of this emulsion, 20 parts by mass of the above acrylic particle dispersion, and 16.7 parts by mass of pure water were mixed with a potassium persulfate mixed solution obtained by mixing 0.036 parts by mass of potassium persulfate. .

Subsequently, this liquid mixture was accommodated in the reaction apparatus provided with the stirrer and the thermometer, and nitrogen substitution was performed at room temperature (25 degreeC) for 1 hour. Next, the temperature was raised and the polymerization reaction was carried out by holding at 65 ° C. for 3 hours. Next, the obtained reaction solution was ice-cooled to stop the polymerization reaction, and the obtained polymer was washed with pure water and then dried at 90 ° C. Thereafter, the dried product was crushed using a hammer mill to obtain ultraviolet shielding particles of Example 1.
The content of zinc oxide in the ultraviolet shielding particles was 30% by mass.

"Evaluation of UV shielding particles"
The ultraviolet shielding particles were observed using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Scanning electron microscope (SEM) images of the ultraviolet shielding particles are shown in FIGS. 9 and 10, and a transmission electron microscope (TEM) image is shown in FIG. 11, respectively.
According to these figures, ultraviolet shielding particles (FIG. 9 and FIG. 11 (a)) in which a resin composition containing zinc oxide is attached to one or more places on the surface of acrylic beads, and acrylic beads containing zinc oxide-containing resin. Ultraviolet shielding particles (FIGS. 10 and 11 (b)) coated with the composition and having two spherical zinc oxide-containing resin compositions attached thereto were confirmed.

"Preparation of UV shielding dispersion"
60 parts by mass of the above-mentioned ultraviolet shielding particles, 51 parts by mass of decamethylcyclopentasiloxane (D5) SH245 (manufactured by Toray Dow Corning), and polyether-modified silicone SH3775M (manufactured by Toray Dow Corning) ) 9 parts by mass was mixed and dispersed for 3 hours at 2500 rpm using a sand mill to obtain the ultraviolet shielding dispersion of Example 1.

"Evaluation of UV shielding dispersion"
Using the obtained ultraviolet shielding dispersion, the film thickness was adjusted to 32 μm with a wire bar and applied to a quartz plate to prepare a coating film (sample for measurement).
Subsequently, the spectral transmittance of this coating film was measured using SPF analyzer UV-1000S (manufactured by Labsphere, USA). The resulting spectral transmittance graph is shown in FIG.

[Example 2]
"Production of UV shielding particles"
Acrylic particle dispersion was prepared by adding 30 parts by mass of acrylic particles MP-2200 (average particle size: 0.3 μm, manufactured by Soken Chemical Co., Ltd.) to 70 parts by mass of pure and using a homogenizer.

  50 parts by mass of zinc oxide (average primary particle size: 0.02 μm, manufactured by Sumitomo Osaka Cement), 47 parts by mass of methyl methacrylate and 3 parts by mass of a phosphoric acid ester type surfactant are mixed and dispersed for 2 hours using a sand mill. The monomer (MMA) dispersion liquid in which the zinc oxide fine particles were dispersed in methyl methacrylate was obtained.

  Next, 30 parts by mass of the monomer (MMA) dispersion obtained, 64.9 parts by mass of pure water, 0.9 parts by mass of sodium dodecylbenzenesulfonate, 3.9 parts by mass of ethylene glycol dimethacrylate, 0 3 parts by mass were mixed and emulsified using a homogenizer to prepare an emulsion.

  Next, 60 parts by mass of this emulsion, 20 parts by mass of the above acrylic particle dispersion, and a potassium persulfate mixed solution in which 0.036 parts by mass of potassium persulfate was mixed with 16.7 parts by mass of pure water were mixed. .

  Subsequently, this liquid mixture was accommodated in the reaction apparatus provided with the stirrer and the thermometer, and nitrogen substitution was performed at room temperature (25 degreeC) for 1 hour. Next, the temperature was raised and the polymerization reaction was carried out by holding at 65 ° C. for 3 hours, and then the reaction was stopped by cooling with ice to obtain a polymerization reaction solution.

Mix 77 parts by weight of methyl methacrylate and 3 parts by weight of a phosphoric acid ester type surfactant, then add 20 parts by weight of avobenzone (Parsol 1789 (registered trademark)) and dissolve to dissolve the organic UV absorber-containing MMA solution. Obtained.
Next, 30 parts by mass of this organic ultraviolet absorber-containing MMA solution and a potassium persulfate mixed solution obtained by dissolving 0.036 parts by mass of potassium persulfate in 69.964 parts by mass of pure water are mixed and emulsified with a homogenizer. Thus, an emulsion was obtained.

  Next, 16.7 parts by mass of this emulsified liquid and 83.3 parts by mass of the above-mentioned polymerization reaction liquid were mixed, and after nitrogen substitution was performed at room temperature (25 ° C.) for 1 hour, the temperature was raised to 65 ° C. The polymerization reaction was carried out for 3 hours. Next, the obtained reaction solution was ice-cooled to stop the polymerization reaction, and the obtained polymer was washed with pure water and then dried at 90 ° C. Thereafter, the dried product was pulverized using a hammer mill to obtain ultraviolet shielding particles of Example 2.

"Evaluation of UV shielding particles"
The ultraviolet shielding particles were observed using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). A scanning electron microscope (SEM) image of the ultraviolet shielding particles is shown in FIG. 13, and a transmission electron microscope (TEM) image is shown in FIG.
According to these figures, ultraviolet shielding particles (FIG. 13 and FIG. 14 (a)) to which a resin composition containing zinc oxide is attached at one or more positions on the acrylic bead surface, the acrylic bead surface and zinc oxide are attached. Ultraviolet shielding particles (FIG. 13 and FIG. 14 (b)) in which the resin composition containing avobenzone was adhered to one or more positions on the surface of the resin composition containing were confirmed. Moreover, the ultraviolet shielding particle | grains by which the zinc oxide containing resin composition coat | covered the surface of the acrylic bead and the avobenzone containing resin composition adhered to the surface were also confirmed.

"Preparation of UV shielding dispersion"
60 parts by mass of the ultraviolet shielding particles described above, 51 parts by mass of decamethylcyclopentasiloxane (D5) SH245 (manufactured by Toray Dow Corning), and polyether-modified silicone SH3775M (manufactured by Toray Dow Corning) ) 9 parts by mass was mixed and dispersed for 3 hours at 2500 rpm using a sand mill to obtain an ultraviolet shielding dispersion of Example 2.

"Evaluation of UV shielding dispersion"
Using the obtained ultraviolet shielding dispersion, the film thickness was adjusted to 32 μm with a wire bar and applied to a quartz plate to prepare a coating film (sample for measurement).
Subsequently, the spectral transmittance of this coating film was measured using SPF analyzer UV-1000S (manufactured by Labsphere, USA). The resulting spectral transmittance graph is shown in FIG.

[Comparative Example 1]
"Production of metal oxide-containing resin particles"
200 parts by mass of zinc oxide fine particles having an average primary particle size of 0.02 μm (manufactured by Sumitomo Osaka Cement), 188 parts by mass of methyl methacrylate, and 12 parts by mass of a phosphoric acid ester type surfactant are mixed and dispersed for 2 hours using a sand mill. The monomer (MMA) dispersion liquid in which the zinc oxide fine particles were dispersed in methyl methacrylate was obtained.

  Next, 105.0 parts by mass of the obtained monomer (MMA) dispersion, 229.5 parts by mass of pure water, 0.5 parts by mass of sodium dodecylbenzenesulfonate, 14.0 parts by mass of ethylene glycol dimethacrylate, silicone-based antifoaming 1.0 part by mass of the agent was mixed and stirred using a homogenizer to obtain an emulsion.

Next, 320.0 parts by mass of the obtained emulsion, 79.856 parts by mass of pure water, and 0.144 parts by mass of potassium persulfate were mixed to obtain a mixed solution.
Subsequently, this liquid mixture was accommodated in the reaction apparatus provided with the stirrer and the thermometer, and nitrogen substitution was performed at room temperature (25 degreeC) for 1 hour. Next, the temperature was raised and the polymerization reaction was carried out by maintaining at 65 ° C. for 3 hours, and then the reaction was stopped by cooling with ice. The polymer obtained was washed with pure water and then dried at 90 ° C. Thereafter, the dried product was pulverized using a hammer mill to obtain metal oxide-containing resin particles of Comparative Example 1.
The content of zinc oxide in the metal oxide-containing resin particles was 50% by mass.

"Preparation of UV shielding dispersion"
60 parts by mass of the above metal oxide-encapsulating resin particles, 51 parts by mass of decamethylcyclopentasiloxane (D5) SH245 (manufactured by Toray Dow Corning Co., Ltd.), polyether-modified silicone SH3775M (Toray Dow Corning (stock) 9 parts by mass) were mixed and dispersed at 2500 rpm for 3 hours using a sand mill to obtain an ultraviolet shielding dispersion of Comparative Example 1.

"Evaluation of UV shielding dispersion"
Using the obtained ultraviolet shielding dispersion, the film thickness was adjusted to 32 μm with a wire bar and applied to a quartz plate to prepare a coating film (sample for measurement).
Subsequently, the spectral transmittance of this coating film was measured using SPF analyzer UV-1000S (manufactured by Labsphere, USA). The resulting spectral transmittance graph is shown in FIG.

  According to the results of the spectral transmittance of each of Example 1 and Comparative Example 1, the ultraviolet shielding dispersion liquid of Example 1 was ultraviolet rays although the zinc oxide content was lower than the ultraviolet shielding dispersion liquid of Comparative Example 1. The shielding properties were comparable. That is, it has been confirmed that the ultraviolet shielding effect is enhanced by using the ultraviolet shielding particles according to the configuration of the present invention.

  The ultraviolet shielding particles of the present invention comprise a resin composition comprising a metal oxide having ultraviolet shielding properties in the second resin on the entire surface of the core part made of the first resin or at one or more locations on the surface. Since the first coating film or the one or more first islands are attached to improve the shielding effect, the water-in-oil type (W / O type) is of course used. It can also be applied to water-based cosmetics such as oil-in-water type (O / W type), lotion, sunscreen gel, etc., which were difficult to formulate in the past, improving the freedom of formulation as cosmetics And its industrial value is great.

Claims (1)

A step of dispersing resin particles to be a core part made of the first resin in water to obtain a resin particle-containing aqueous dispersion;
A step of dispersing a metal oxide having ultraviolet shielding properties in a monomer of a second resin containing a dispersant to form a resin monomer dispersion;
A step of suspending or emulsifying the resin monomer dispersion in pure water containing a suspension protective agent, a silicone-based antifoaming agent, a crosslinking agent, and a polymerization initiator to form a suspension or emulsion;
The resin particle-containing aqueous dispersion and the suspension or emulsion are mixed to prepare a mixture, and the mixture is subjected to suspension polymerization or emulsion polymerization to obtain a core material portion made of the first resin. The first coating film or the one or more first island-like substances containing a metal oxide having ultraviolet shielding properties in the second resin are attached to the entire surface or one or more locations on the surface. The process of making UV shielding particles,
Have
The first resin and the second resin are (meth) acrylic resins,
The dispersant is selected from the group consisting of sodium carboxymethylcellulose, sodium alkanesulfonate, sodium polyoxyethylene nonylphenyl ether sulfate, polyoxyethylene alkylphenyl ether phosphate, polyoxyethylene alkyl ether phosphate, and sodium lauryl phosphate. One or more,
The addition ratio of the dispersant to the metal oxide is 1% by mass or more and 50% by mass or less,
In the resin monomer dispersion liquid, the average dispersion particle diameter of the metal oxide is 0.003 μm or more and 0.1 μm or less.