JP2010222444A - Globular composite particle, method for manufacturing the same, and cosmetic containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide globular composite particles which have the desired hardness and/or the softness, and besides which are capable of imparting the high slip properties and covering effect on a cosmetics. <P>SOLUTION: The globular particles comprise an aggregation assembly of a plurality of inorganic particles, and a plurality of flat-shape resin particles selected from styrene-based resin particles, (meth)acrylic-based resin particles and the mixed particles of both the resin particles, wherein the inorganic particles have an average particle diameter of 1 μm or less, the flat-shape resin particles have a round shape as an external shape of such a projection figure as makes the area the largest, and the external shape of a cross section to the direction crossing at a right angle to the projection direction has a shape comprising a protrusion and the concavity corresponding to the protrusion, with the round shape having a diameter (D) of 6 μm or less, the protrusion having such a thickness (H) that a ratio (D/H) of the thickness (H) to the diameter (D) becomes 1.4 or more, and the concavity having the largest inner diameter (d) of 0.1 μm or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to spherical composite particles, a method for producing the same, and a cosmetic containing the same. More specifically, the present invention relates to spherical composite particles in which a plurality of inorganic particles and a plurality of flat resin particles are aggregated, a method for producing the same, and a cosmetic including the same.

Inorganic particles or resin particles are used by blending in makeup cosmetics such as powder foundations and skin cosmetics such as emulsions. As inorganic particles, there are particles such as silica, titanium oxide, and alumina, and particles obtained by surface treatment of these particles. Further, as the resin particles, there are particles made of polystyrene, nylon, silicone or the like.
By blending these particles, the rolling of the particles on the skin can improve the touch (for example, slipperiness). For example, in the case of inorganic particles, the hardness is relatively high, so that a dry feel that is mainly smooth is obtained, and in the case of resin particles, the hardness is relatively low, so that a soft feel is obtained. This feel depends on the particle shape as well as the average particle size and particle size distribution.

As the particles, spherical particles are generally used. However, bowl-shaped particles (Japanese Patent Laid-Open No. 6-172125: Patent Document 1), flat, lenticular and hemispherical particles (Japanese Patent Laid-Open No. 2001-278746). Non-spherical particles such as a publication: Patent Document 2) have also been proposed.
However, the single particles are insufficient in improving the touch required for cosmetics such as elongation on the skin and slipperiness. For the purpose of further improving the touch, a pressure-disintegrating spherical powder (spherical composite particles) prepared by combining spherical resin particles by spray drying has been proposed (Japanese Patent Laid-Open No. 2001-323070). Patent Document 3, JP 2006-348266 A: Patent Document 4). Such spherical composite particles are said to be further improved in elongation and slipperiness on the skin by gradually disintegrating into individual spherical resin particles by applying shear stress.

JP-A-6-172125 JP 2001-278746 A JP 2001-323070 A JP 2006-348266 A

In makeup cosmetics such as powder foundation, it is desired to improve the concealing effect of pigment trouble such as melasma. Therefore, the spherical composite particles contained in the cosmetics can be provided with high slipperiness and a concealing effect on the cosmetics while having a desired hardness and / or softness according to the required degree of touch. It is desirable to have a configuration.
Also, in the fields other than cosmetics, for example, in the field of paints, spherical composite particles having a structure capable of imparting high slipperiness and concealment effect to paints while having desired hardness and / or softness are provided. It is hoped to do.

As a result of intensive studies, the inventors of the present invention have found that the above problems can be solved by spherical composite particles in which a plurality of inorganic particles and a plurality of flat resin particles having a specific shape are aggregated, and have reached the present invention.
Thus, according to the present invention, a plurality of inorganic particles and a plurality of flat resin particles selected from styrene resin particles, (meth) acrylic resin particles and a mixture of both resin particles are assembled,
The inorganic particles have an average particle size of 1 μm or less;
The flat resin particle has a circular outer shape in the figure projected so as to maximize the area, and the outer shape of a cross section in a direction orthogonal to the direction of the projection is formed by a convex portion and a concave portion corresponding to the convex portion. Have
The circular shape has a diameter (D) of 6 μm or less;
The convex portion has a thickness (H) at which the ratio (D / H) of the thickness (H) to the diameter (D) is 1.4 or more,
A spherical composite particle is provided in which the concave portion has a maximum inner diameter (d) of 0.1 μm or more.

According to the present invention, there is also provided a method for producing the spherical composite particle,
The spherical composite particles are obtained by spray-drying a dispersion in which the flat resin particles and the inorganic particles are dispersed in an aqueous medium.
A method for producing spherical composite particles, characterized in that the spray drying is performed under conditions of a dispersion liquid inlet temperature of a spray dryer of 90 to 230 ° C and a spherical composite particle outlet temperature of a spray dryer of 40 to 120 ° C. Provided.
Furthermore, according to this invention, the cosmetics containing 1-80 weight% of said spherical composite particles are provided.

According to the present invention, the desired hardness and / or softness can be adjusted according to the required feel according to the use such as cosmetics, and high slipperiness and concealment can be imparted to the formulation. A spherical composite particle having a configuration can be provided.
Further, since the spherical composite particles have an average particle diameter of 1 to 150 μm, higher slipping properties and concealing properties can be obtained.
Furthermore, since the flat resin particles have an average particle diameter of 0.1 to 600 times the average particle diameter of the inorganic particles, higher slipping property and concealment effect can be imparted to the blend.
In addition, when the circle has a diameter of 0.5 to 6 μm and the ratio (D / H) is 1.4 to 4, a particularly higher hiding effect can be imparted to the formulation.

Furthermore, when the inorganic particles are selected from titanium oxide, zinc oxide and iron oxide, a particularly higher hiding effect can be imparted to the formulation.
Further, since the spherical composite particles are particles containing 5 to 99 parts by weight of inorganic particles with respect to 100 parts by weight of the flat resin particles, higher slipping and concealing properties can be obtained.
Spherical composite particles can be easily obtained by spray-drying a dispersion in which flat resin particles and the inorganic particles are dispersed in an aqueous medium under a specific temperature condition.
Moreover, the cosmetics which mix | blended the spherical composite particle have desired hardness and / or softness, and high slipperiness and a concealment effect.

It is the schematic of a flat resin particle. 4 is an electron micrograph of flat resin particles of Synthesis Example 1. 6 is an electron micrograph of spherical composite particles of Synthesis Example 4.

The spherical composite particles of the present invention are formed by aggregating a plurality of inorganic particles having an average particle diameter of 1 μm or less and a plurality of flat resin particles having an average particle diameter of 6 μm or less. Such spherical composite particles can be easily produced by spray drying.
The spherical composite particles have excellent slipperiness due to the distribution of the inorganic particles in the surface layer of the flat resin particles. In particular, by producing spherical composite particles by spray drying, the inorganic particles can be more uniformly distributed on the surface of the flat resin particles than a mixture obtained by simply mixing flat resin particles and inorganic particles. As a result, the slipperiness of the spherical composite particles can be further improved.
Further, the inventors consider that a better feeling of use was obtained as a result of imparting a specific pressure disintegration property to the spherical composite particles by using flat resin particles having a specific shape.

(Flat resin particles)
The “flat resin particles” have a shape in which the outer shape of the figure projected so as to maximize the area is circular, and the outer shape of the cross section along the direction of the projection is formed by a convex portion and a concave portion corresponding to the convex portion. ing. This shape is a human erythrocyte shape as shown in the schematic diagrams of FIGS. 1 (a) and 1 (c) are views projected to maximize the area, FIG. 1 (a) is a schematic top view, FIG. 1 (c) is a schematic bottom view, and FIG. (B) is a schematic sectional drawing of the direction orthogonal to the direction of projection, and FIG.1 (d) is a schematic side view of the direction orthogonal to the direction of projection. As shown in FIGS. 1A to 1D, the flat resin particles are:
(1) The circle has a diameter of 6 μm or less (D, in other words, the longest diameter of the flat resin particles),
(2) The convex portion has a thickness (H) at which the ratio (D / H) of the thickness (H) to the diameter (D) is 1.4 or more,
(3) The concave portion has a maximum inner diameter (d) of 0.1 μm or more.

When the circular diameter (D) is larger than 6 μm, unevenness is likely to occur in the degree of flattening when producing flat resin particles. As a result, the performance of the spherical composite particles may vary. A preferable diameter is 0.5 to 6 μm.
When the ratio (D / H) is less than 1.4, the concealability may be deteriorated because the shape of the resin particles is too close to a sphere. A preferred ratio (D / H) is 1.4-4.
When the maximum inner diameter (d) is less than 0.1 μm, the shape of the resin particles may be nearly spherical and the concealing effect may be insufficient. A preferable maximum inner diameter (d) is 0.1 to 3.5 μm.
The circular diameter (D) may have a length that is 1.5 to 8 times the maximum inner diameter (d).
Further, the flat resin particles preferably have a diameter (D) of 0.1 to 600 times the average particle diameter of the inorganic particles. When the diameter (D) is less than 0.1 times or more than 600 times, the inorganic particles may be too small or too large with respect to the flat resin particles, and the slipperiness and concealment effect may be insufficient. More preferably, the diameter (D) of the flat resin particles is 0.15 to 500 times the average particle diameter of the inorganic particles.

The flat resin particles are made of styrene resin particles or (meth) acrylic resin particles. Here, (meth) acryl means acryl or methacryl. The composite resin particles are composed of a plurality of flat resin particles. In this case, the plurality of flat resin particles may be composed of only styrene resin particles or (meth) acrylic resin particles. It may consist of mixed particles of resin particles.
Styrenic resin particles are resin particles derived from a monomer composition containing a styrene monomer as a main component (more than 50% by weight). Examples of the styrene monomer include monofunctional monomers such as styrene and α-methylstyrene, and polyfunctional monomers such as divinylbenzene. Examples of the monomer other than the styrene monomer in the monomer composition include a (meth) acrylic monomer, a vinyl halide monomer, and a vinyl cyan monomer.

  The (meth) acrylic resin particles are resin particles derived from a monomer composition containing a (meth) acrylic monomer as a main component (greater than 50% by weight). (Meth) acrylic monomers include monofunctional monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate, ethylene glycol di (meth) acrylate, and trimethylolpropane. A polyfunctional monomer such as triacrylate may be mentioned. Examples of the monomer other than the (meth) acrylic monomer in the monomer composition include styrene resin particles, a vinyl halide monomer, and a vinylcyan monomer.

(Manufacturing method of flat resin particles)
The flat resin particles can be produced, for example, by an emulsion polymerization method using seed particles.
Specifically, the emulsion polymerization system is a method of emulsion polymerization in a medium containing a water-insoluble organic solvent having an interfacial tension with respect to specific water (a), and a specific amount of a crosslinkable monomer is added to the emulsion polymerization system. A method (b) etc. are mentioned.

Method (a)
In the method (a), the emulsion polymerization system is a system in which seed particles, a styrene monomer and / or a (meth) acrylic monomer, and a water-insoluble organic solvent are dispersed in an aqueous medium. Other additives such as a polymerization initiator, a molecular weight modifier, and a surfactant may be added to the emulsion polymerization system.

(1) Seed particles Examples of seed particles include aromatic vinyl monomers such as styrene and α-methylstyrene, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and the like. Examples thereof include particles composed of a homopolymer of an acrylate monomer, vinyl acetate, or other copolymerizable monomer, or a block, ramdam, or graft copolymer thereof.
The size and shape of the seed particles are not particularly limited, but usually 0.1 to 2 μm spherical particles are used.
The method for producing seed particles is not particularly limited, and methods such as emulsion polymerization, soap-free emulsion polymerization, and suspension polymerization can be used. Considering the uniformity of the seed particle size and the simplicity of the production method, emulsion polymerization and soap-free emulsion polymerization are preferred.

(2) Water-insoluble organic solvent As water-insoluble organic solvent, 48 dyne / cm or more of n-pentane, n-hexane, n-heptane, i-octane, n-octane, n-decane, 1-chlorodecane, etc. The solvent which has the interfacial tension with respect to 20 degreeC water is mentioned.
The water-insoluble organic solvent is preferably used in the range of 1 to 50% by weight with respect to the total amount of seed particles, styrene monomer and / or (meth) acrylic monomer.

(3) Aqueous medium Examples of the aqueous medium include water, a mixed medium of water and a lower alcohol (for example, methanol, ethanol, etc.), and the like.
The aqueous medium is preferably used in the range of 100 to 1000 parts by weight with respect to 100 parts by weight of the total amount of seed particles, styrene monomer and / or (meth) acrylic monomer.

(4) Other additives (i) Polymerization initiator As the polymerization initiator, both water-soluble and oil-soluble initiators can be used. For example, persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate, organic peroxides such as benzoyl hydroperoxide, azo compounds such as 4,4′-azobis (4-cyanopentanoic acid), Examples thereof include redox initiators such as potassium persulfate-sodium thiosulfate and hydrogen peroxide-ascorbic acid.
The polymerization initiator is preferably used in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the styrene monomer and / or the (meth) acrylic monomer.

(Ii) Molecular weight regulator As molecular weight regulator, alpha-methylstyrene dimer, mercaptans such as n-octyl mercaptan, t-dodecyl mercaptan, terpenes such as t-terpinene, terpinolene, dipentene, halogenated hydrocarbons Chain transfer agents such as (eg, chloroform, carbon tetrachloride) can be used. The molecular weight regulator is preferably used in the range of 1 to 20 parts by weight with respect to 100 parts by weight of the styrene monomer and / or the (meth) acrylic monomer.

(Iii) Surfactant The surfactant is not particularly limited, and any of an anionic surfactant, a nonionic surfactant, a cationic surfactant, and a zwitterionic surfactant can be used.
Examples of the anionic surfactant include fatty acid oils such as sodium oleate and castor oil potassium, alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalene sulfone. Acid salts, alkane sulfonates, dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfonate formalin condensates, polyoxyethylene alkyl phenyl ether sulfates, polyoxyethylene alkyl sulfates and the like.

Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxy Examples include ethylene-oxypropylene block polymers.
Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.
Examples of the zwitterionic surfactant include lauryl dimethylamine oxide and phosphate ester or phosphite ester surfactants.
You may use the said surfactant individually or in combination of 2 or more types.
The surfactant concentration during the production of the flat resin particles is preferably set to a critical micelle concentration or less in order to suppress the generation of new particles (particles composed only of monomers).

(Iv) Other Water-soluble polymerization inhibitors such as nitrites, sulfites, hydroquinones, ascorbic acids, water-soluble vitamin Bs, citric acid, polyphenols and the like to suppress the generation of emulsified particles in an aqueous medium May be used.
A suspension stabilizer may be added in order to improve the polymerization stability and increase the effect of suppressing fusion between particles during the production of flat resin particles. For example, phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, pyrophosphates such as calcium pyrophosphate, magnesium pyrophosphate, aluminum pyrophosphate, zinc pyrophosphate, magnesium carbonate, calcium hydroxide, hydroxide Examples thereof include poorly water-soluble inorganic compounds such as magnesium, aluminum hydroxide, calcium metasilicate, and calcium sulfate, and water-soluble polymers such as polyvinyl alcohol. The addition amount of the suspension stabilizer is usually 0.5 to 15 parts by weight with respect to 100 parts by weight of the monomer.

(5) Manufacturing conditions Flat resin particles are obtained by adding a monomer to an aqueous medium and performing polymerization.
During the polymerization reaction, it is preferable to stir the aqueous suspension in which the monomer is dispersed as spherical droplets. For example, the stirring may be performed gently enough to prevent floating of the spherical droplets and sedimentation of the particles after polymerization. Good.
The polymerization temperature is preferably about 30 to 100 ° C, more preferably about 40 to 80 ° C. And as time to hold | maintain this superposition | polymerization temperature, about 1 to 20 hours are preferable.

Method (b)
In the method (b), a specific amount of a crosslinkable monomer is used without using a water-insoluble organic solvent. Flat resin particles can be obtained in the same manner as in the method (a) except that a specific amount of the crosslinkable monomer is used.

(I) Crosslinkable monomer Crosslinkable monomers include diene monomers such as butadiene, and polymerizable unsaturated bonds such as divinylbenzene, ethylene glycol di (meth) acrylate, and trimethylolpropane trimethacrylate. Examples thereof include monomers having two or more in one molecule.
The crosslinkable monomer is preferably used in the range of 3 to 15% by weight based on the total amount of the monomers. By being within this range, resin particles having a high degree of flattening can be obtained.

(Ii) Seed particles In the method (b), it is preferable to adjust the weight average molecular weight of the seed particles to a range of 5,000 to 150,000 as measured by gel permeation chromatography. It is more preferable to adjust to 000, and it is still more preferable to adjust to 15,000-50,000. The weight average molecular weight of the seed particles can be adjusted within this range by adjusting the amount of the polymerization initiator used or adding a molecular weight regulator. Examples of the molecular weight modifier include α-methylstyrene dimer, mercaptans such as n-octyl mercaptan and t-dodecyl mercaptan, terpenes such as t-terpinene, terpinolene and dipentene, and halogenated hydrocarbons such as carbon tetrachloride. Can be used. The weight average molecular weight of the seed particles can also be adjusted by adjusting the addition amount of these molecular modifiers.

When the weight average molecular weight of the seed particles is larger than 150,000, the degree of flatness of the obtained irregularly shaped fine particles may be lowered. That is, when the weight average molecular weight of the seed particles is greater than 150,000, the monomer absorption capacity of the seed particles decreases, and the monomer of the monomer mixture is polymerized independently without being absorbed by the seed particles. Spherical fine particles different from the target shape may be generated.
On the other hand, when the weight average molecular weight of the seed particles is less than 5,000, not only is it difficult to obtain the desired seed particles even when a large amount of chain transfer agent is used, but the finally obtained irregular shaped fine particles The strength of the may decrease.

Of the methods (a) and (b), in the method (a), a water-insoluble organic solvent may remain in the obtained flat resin particles. Therefore, the flat resin particles obtained by the method (a) are not preferable as a raw material for use in living bodies such as cosmetics. In the method (b), since the flat resin particles can be produced even in the absence of the water-insoluble organic solvent, the method (b) is suitable as a raw material for use in a living body.
The flat resin particles can also be produced by the methods described in JP-A-2-14222, JP-A-7-188313, JP-A-11-181037, and the like.

(Inorganic particles)
As the inorganic particles, particles of silica, titanium oxide, zinc oxide, magnesium oxide, iron oxide or the like can be used. Among the above, when titanium oxide, zinc oxide or the like is used, an ultraviolet absorbing effect can be imparted to the spherical composite particles, and when magnesium oxide, iron oxide or the like is used, a deodorizing effect can be imparted to the spherical composite particles.
The inorganic particles may further carry a metal such as copper, silver or zinc. By carrying these metals, an antibacterial action can be further imparted to the inorganic particles. The metal is preferably contained in an amount of 1 to 20% by weight based on the total amount of inorganic particles.
The inorganic particles may be inorganic particles that have been subjected to a hydrophobic treatment.

  Examples of hydrophobizing agents that can be used for hydrophobizing colloidal silica include alkylsilazane compounds such as hexamethyldisilazane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, methyltrimethoxysilane, butyltrimethyl. Alkyl alkoxysilane compounds such as methoxysilane, chlorosilane compounds such as dimethyldichlorosilane and trimethylchlorosilane, silicone oil, silicone varnish, and the like can be used.

Examples of hydrophobizing agents that can be used for hydrophobizing titanium oxide include siloxanes such as dimethylpolysiloxane, methylhydrogen polysiloxane, and organically modified silicone oil, silane coupling agents, titanate coupling agents, and aluminum cups. Examples thereof include coupling agents such as ring agents and fluorine-based coupling agents, higher fatty acids, higher alcohols, and amines having a higher alkyl group. In addition, before hydrophobizing the titanium oxide, its surface is coated with an oxide or hydrous oxide such as aluminum, silicon, zirconium, titanium, zinc, tin, etc., thereby improving the affinity with the hydrophobizing agent. May be.
The inorganic particles are not particularly limited, and various particles such as a spherical shape, a substantially spherical shape, a needle shape, a dendritic shape, and an indefinite shape can be used.

  As the inorganic particles, particles having an average particle diameter of 1 μm or less are used. When the average particle diameter exceeds 1 μm, the smoothness when applied to the surface to be coated such as skin may be lowered. The average particle diameter is preferably in the range of 0.01 to 1 μm. When the thickness is 0.01 μm or more, the resin particle slurry is agglomerated at the time of spray drying, and thus cannot be suitably used. In addition, an average particle diameter means the average value of the largest diameter of particle | grains.

  It is preferable that the usage-amount of an inorganic particle is the range of 5-99 weight part with respect to the usage-amount of flat resin particle 100 weight. When the amount of the inorganic particles used is less than 5 parts by weight, the blending effect of the inorganic particles may not be obtained. Moreover, when it exceeds 99 weight part, the smoothness at the time of application | coating and uniformity may be insufficient. A more preferable usage amount is 10 to 90 parts by weight, and a particularly preferable usage amount is 15 to 85 parts by weight.

(Spherical composite particles)
The spherical composite particles preferably have an average particle diameter of 1 to 150 μm. When the average particle diameter is less than 1 μm, the pressure disintegration property of the spherical composite particles is lowered, and the smoothness during coating may be lowered. Moreover, when larger than 150 micrometers, the foreign material feeling at the time of application | coating may arise easily. A more preferable average particle diameter is 5 to 130 μm. Here, the spherical shape does not strictly mean a true spherical shape, and the cross section may be elliptical or partially uneven.
The ratio of the inorganic particles and the flat resin particles occupying each spherical composite particle is substantially the same as the amount of the inorganic particles and the flat resin particles used as raw materials when producing the spherical composite particles.

(Method for producing spherical composite particles)
A spray-drying method is mentioned as a manufacturing method of spherical composite particles. Moreover, the method of grind | pulverizing the lump which consists of a mixture of an inorganic particle and a flat resin particle can also be used. Among these, the spray drying method is preferable because the average particle size and shape can be controlled.

  The spray drying method generally uses a dryer such as a spray dryer to spray the water dispersion (inorganic particles and flat resin particles dispersed in an aqueous medium) together with a gas stream to dry the particles. It is a method to make it. In the spray drying method, the average particle size and shape can be adjusted by appropriately adjusting the supply speed and drying temperature of the aqueous dispersion, and the rotation speed of the rotation mechanism when the spray dryer has a rotation mechanism. Is possible. Specifically, when the supply speed is increased, the average particle diameter increases and the shape tends to be non-spherical. When the supply speed is slowed down, the average particle size becomes small and the shape tends to be a perfect sphere. When the drying temperature of the aqueous medium is increased, the average particle size is decreased and the shape tends to be a true sphere. When the drying temperature of the aqueous medium is lowered, the average particle size increases and the shape tends to be non-spherical. As the number of rotations increases, the average particle diameter decreases and the shape tends to be a perfect sphere. When the rotational speed is small, the average particle diameter is large and the shape tends to be non-spherical.

  Among these, the drying temperature is an important requirement in the conditions of the spray drying method. In order to define the drying temperature, it is preferable that the temperature at the portion where the water dispersion is introduced into the spray dryer (spray inlet temperature) and the outlet temperature of the spherical composite particles are in a predetermined range. Specifically, the spray inlet temperature is in the range of 90 to 230 ° C, and the outlet temperature of the spherical composite particles is in the range of 40 to 120 ° C. When the spray inlet temperature is higher than 230 ° C., fusion between the flat resin particles forming the spherical composite particles is promoted, the pressure disintegration property is remarkably lowered, and the usability may be deteriorated. When the spray inlet temperature is less than 90 ° C., the drying efficiency is lowered, and thus productivity may be lowered. Furthermore, since the fusion between the flat resin particles is insufficient, the resin particles may easily collapse due to shear stress. Therefore, the feeling of use may be inferior. Further, when the outlet temperature of the spherical composite particles is too low, drying may be insufficient. On the other hand, when too high, the fusion | melting between flat resin particles is accelerated | stimulated too much, and the problem which a usability | use_condition worsens arises. A more preferable spray inlet temperature is 100 to 210 ° C, and an outlet temperature is 50 to 100 ° C.

Further, the spray inlet temperature is preferably higher than the outlet temperature from the viewpoint of preventing fusion between the flat resin particles, and is preferably higher than the outlet temperature in the range of 50 to 110 ° C.
The residence time in the dryer until the aqueous dispersion in the spray dryer is discharged as spherical composite particles is 10 to 50 seconds.
In addition, as a dispersion method of the inorganic particles in the aqueous medium, for example, a method of dispersing by a stirring force such as a propeller blade, a method using a homomixer that is a disperser using a high shear force composed of a rotor and a stator, Examples include a method of dispersing using an ultrasonic disperser.

(Use of spherical composite particles)
The spherical composite particles have high slipperiness and a high concealing effect on the coated surface. Therefore, it is preferable to use it for applications requiring these properties. Examples of such applications include cosmetics and paints. In particular, it is preferable to use it in cosmetics from the viewpoint of having a desired hardness and / or softness and having high slipperiness and concealment effect.
The content of the spherical composite particles in the cosmetic can be appropriately set according to the type of cosmetic, but is preferably 1 to 80% by weight, and more preferably 2 to 70% by weight.
When the content of the spherical composite particles relative to the cosmetic is less than 1% by weight, a clear effect due to the inclusion of the spherical composite particles may not be recognized. On the other hand, when the content of the spherical composite particles exceeds 80% by weight, a remarkable effect corresponding to the increase in the content may not be recognized, which is not preferable in terms of production cost.

  The cosmetic is not particularly limited as long as it exhibits the above-mentioned effects due to the inclusion of the spherical composite particles. For example, liquid systems such as pre-shave lotion, body lotion, lotion, cream, emulsion, body shampoo, antiperspirant, etc. Cosmetics, soaps, scrubs, facial cleansing cosmetics, packs, shave creams, funny products, foundations, lipsticks, lip balms, blushers, eyebrows cosmetics, nail polish cosmetics, hair cosmetics, hair dyes, hair conditioners , Aromatic cosmetics, toothpastes, bath preparations, sunscreen products, suntan products, body powders, baby powders and the like.

  Components other than the spherical composite particles contained in the cosmetic are not particularly limited, and can be appropriately selected from known substances according to the function required for the cosmetic. Since the spherical composite particles of the present invention are composed of flat resin particles, and the flat resin particles can hold other components in their recesses, the present invention is compared with the spherical composite particles composed of spherical resin particles. More other ingredients can be retained.

EXAMPLES Hereinafter, although this invention is demonstrated using an Example, this invention is not limited by this. In addition, the measuring method of an average particle diameter, the measuring method of D, H, d of a flat resin particle, a sensory test, and the evaluation method of concealment are described below.
(Average particle size of seed particles)
The average particle diameter of the seed particles is measured with an LS230 type manufactured by Beckman Coulter. Specifically, 0.1 g of particles and 10 ml of a 0.1% nonionic surfactant solution are put into a test tube and mixed for 2 seconds with a touch mixer TOUCHMIXER MT-31 manufactured by Yamato Kagaku. Thereafter, the mixed solution in the test tube is dispersed for 10 minutes using a commercially available ultrasonic cleaner, ULTRASONIC CLEANER VS-150, manufactured by Velvo Crea. The particle size is measured while irradiating ultrasonic waves with the LS230 type manufactured by Beckman Coulter, Inc. The optical model at that time matches the refractive index of the produced particles. The average value of the particle diameter of 0.1 g of particles is the average particle diameter.

(Measurement method of D, H, d of flat resin particles)
The diameter D of the flat resin particles, the thickness H of the convex portion, and the maximum inner diameter d of the concave portion are measured as follows.
Using a scanning electron microscope JSM-6360LV (manufactured by JEOL Ltd.), arbitrary 30 flat resin particles were observed at a magnification of 5,000 to 10,000 times, each part was measured, and the average value thereof was a diameter D, The thickness is H and the inner diameter is d.

(Average particle diameter of spherical composite particles)
The electrolyte solution is filled in pores having a pore diameter of 50 to 400 μm, the volume is obtained from the change in conductivity of the electrolyte solution when the spherical composite particles pass through the electrolyte solution, and the average particle diameter is calculated. Specifically, the measured average particle diameter is a volume average particle diameter measured by a Coulter Multisizer II manufactured by Beckman Coulter. In measurement, calibration is performed using an aperture suitable for the particle size of the spherical composite particles to be measured according to REFERENCE MANUAL FOR THE COULTER MULTISIZER (1987) issued by Coulter Electronics Limited.

Specifically, 0.1 g of particles and 10 ml of a 0.1% nonionic surfactant solution are put into a commercially available glass test tube, mixed for 2 seconds with a touch mixer TOUCHMIXERMT-31 manufactured by Yamato Scientific Co., Ltd. In a beaker filled with ISOTON2 (manufactured by Beckman Coulter, Inc .: electrolyte for measurement) equipped with a main body, drop with a dropper while gently stirring to adjust the concentration meter reading on the main body screen to about 10%. Next, aperture size, Current, Gain, Polarity are added to Multisizer 2 body. REFERENCE MANUAL FOR THE issued by Coulter Electronics Limited.
Input according to COULTER MULTISIZER (1987) and measured manually. During the measurement, the beaker is gently stirred to the extent that bubbles do not enter, and the measurement is terminated when 100,000 aggregates are measured.

(Sensory test)
The composite particles of Examples and Comparative Examples are evaluated by a sensory test by 10 panelists. As evaluation items in this test, smoothness, soft feeling, and elongation are selected, and each item is evaluated on the basis of the following criteria.
5 ... Good 4 ... Slightly good 3 ... Normal 2 ... Slightly bad 1 ... Poor The result of each evaluation item is represented by the average value of the test results of 10 people. Comprehensive judgment is made according to the following criteria by summing up the average values of each evaluation item.
○ …… 12 or more in total △ …… 9.0 to 11.9 in total
X: 8.9 or less in total However, if there is a value of 2.5 to 3.5 among the average value of each item, Δ is marked, and if there is 2.4 or less, x is marked.

(Method for evaluating concealment)
The powder foundations of the examples and comparative examples are evaluated for concealment by five panelists. Specifically, the prepared powder foundation is applied around the vein part of the back of the hand, and the difference in the color of the non-vein part depending on the presence or absence of application is observed. Three-stage evaluation was performed according to the following criteria.
3 ... Not conspicuous 2 ... Slightly conspicuous 1 ... Conspicuous The concealment property is expressed as an average value of the test results of 5 persons and evaluated according to the following criteria.
○ …… 2.1 to 3.0
△ ... 1.5-2.0
× …… 1.9 or less

Example 1
[Preparation of flat resin particles]
(first stage)
In a polymerization vessel equipped with a stirrer and a thermometer, 1700 g of deionized water in which 0.30 g of sodium p-styrenesulfonate (manufactured by Tosoh Corporation) was dissolved was added. A monomer mixture composed of 300 g of styrene and 3.2 g of α-methylstyrene dimer prepared in advance was charged into the obtained solution, and the resulting mixture was heated to 70 ° C. while purging with nitrogen under stirring. . After maintaining the internal temperature at 70 ° C. and adding 40 g of deionized water in which 3.0 g of potassium persulfate was dissolved as a polymerization initiator, the monomer mixture was polymerized over 17 hours. The average particle diameter of the polymer particles (seed particles) in the obtained emulsion was 0.36 μm.

(Second stage)
A polymerization vessel equipped with a stirrer and a thermometer was charged with 750 g of deionized water in which 0.16 g of sodium dodecylbenzenesulfonate was dissolved, and 111 g of the emulsion (solid content 15% by weight) obtained in the first stage was added to the polymerization vessel. Until warmed. The whole amount of a monomer mixture composed of 250 g of styrene and 12.5 g of divinylbenzene prepared in advance was added thereto, and the atmosphere was replaced with nitrogen under stirring. After maintaining the internal temperature of the polymerization vessel at 70 ° C., adding 30 g of deionized water in which 2.5 g of potassium persulfate, which is a water-soluble initiator, was dissolved, and polymerizing the monomer mixture over 7 hours And cooled to room temperature (about 25 ° C.). The obtained suspension was oven dried at 70 ° C., and the obtained particles were observed with a scanning electron microscope. The bottom diameter (D) was 1.2 μm, and the thickness from the bottom to the top of the convex surface ( H) was 0.73 μm, and flat resin particles having a recess having a maximum inner diameter (d) of 0.38 μm at the center of the bottom of the particles ((D / H) = 1.6). FIG. 2 shows an electron micrograph of the flat resin particles.

[Production of spherical composite particles]
40 g of TTO-55 (A) (manufactured by Ishihara Sangyo Co., Ltd .: titanium oxide, particle size: 0.03-0.05 μm) and 100 g of deionized water are added to the above suspension (solid content: 25% by weight). An inorganic particle mixed slurry was obtained by stirring for 10 minutes with a K homomixer (manufactured by Koki Kogyo Co., Ltd.). This slurry was dried under the following conditions using a spray dryer (model: atomizer take-up system, model number: TRS-3WK) manufactured by Sakamoto Giken Co., Ltd., to obtain composite particles.

Supply speed: 25 ml / min
Atomizer speed: 16000rpm
Inlet temperature: 170 ° C
Outlet temperature: 80 ° C
The obtained composite particles had an average particle diameter of 33 μm. As a result of observing the composite particles with an electron microscope (SEM), the composite particles had a spherical shape. The obtained composite particles were subjected to a sensory test. The results are shown in Table 1.

[Production of powder foundation]
A powder part and an oil part having the following composition were prepared.
(Powder part)
21g of composite particles
Talc 38g
22g mica
Titanium oxide 6g
Red iron oxide 0.6g
Yellow iron oxide 1g
Black iron oxide 0.1g
(Oil part)
10g cetyl 2-ethylhexanoate
1 g sorbitan sesquioleate
Preservative 0.2g
Fragrance 0.1g
The above powder part was mixed with a Henschel mixer, and an oil part (excluding fragrance) mixed and dissolved was added thereto and mixed uniformly. After further adding fragrance and mixing, the mixture was pulverized and passed through a sieve. This was compression molded to obtain a powder foundation. Table 2 shows the evaluation results of hiding properties.

Example 2
[Preparation of flat resin particles]
(first stage)
In a polymerization vessel equipped with a stirrer and a thermometer, 67 g of the emulsion in which the seed particles obtained in Example 1 were dispersed and 850 g of pure water in which 0.20 g of sodium p-styrenesulfonate (manufactured by Tosoh Corporation) was dissolved were added. A monomer mixture composed of 150 g of styrene and 1.7 g of α-methylstyrene dimer prepared in advance was added to the obtained mixture, and the mixture was heated to 70 ° C. while purging with nitrogen under stirring. After maintaining the internal temperature at 70 ° C. and adding 40 g of deionized water in which 2.0 g of potassium persulfate was dissolved as a polymerization initiator, the monomer mixture was polymerized over 17 hours. The polymer particles (seed particles) in the obtained emulsion had an average particle size of 0.88 μm.

(Second stage)
Particles were obtained in the same manner as in Example 1 except that 84 g of the emulsion (solid content: 15% by weight) obtained in the first stage was used. When the obtained particles were observed, the particles had a bottom diameter (D) of 2.7 μm, a thickness (H) from the bottom to the top of the convex surface of 1.5 μm, and a maximum inner diameter ( d) Flat resin particles having a recess of 0.9 μm ((D / H) = 1.8).

[Production of spherical composite particles]
Composite as in Example 1 except that the inorganic particles were changed to 50 g of Snowtex C30 (manufactured by Nissan Chemical Industries, Ltd .: colloidal silica, particle size: 0.01-0.02 μm, 30% as solid content of silica). Particles were obtained. The obtained composite particles had an average particle diameter of 32 μm and had a spherical shape. The obtained composite particles were subjected to a sensory test. The results are shown in Table 1.
[Production of powder foundation]
A powder foundation was obtained in the same manner as in Example 1 except that the composite particles were used. Table 2 shows the evaluation results of hiding properties.

Example 3
[Preparation of flat resin particles]
Flat resin particles were obtained in the same manner as in Example 1 except that 250 g of methacrylic acid was used instead of styrene and 12.5 g of ethylene glycol dimethacrylate was used instead of divinylbenzene. A flat resin having a bottom diameter (D) of 1.2 μm, a thickness (H) from the bottom to the top of the convex surface of 0.72 μm, and a recess having a maximum inner diameter (d) of 0.37 μm at the center of the bottom of the particle It was a particle ((D / H) = 1.7).

[Production of spherical composite particles]
Composite particles were obtained in the same manner as in Example 1 except that the amount of TTO-55 (A) used was changed to 150 g. The obtained composite particles had an average particle diameter of 31 μm and had a spherical shape. The obtained composite particles were subjected to a sensory test. The results are shown in Table 1.
[Production of powder foundation]
A powder foundation was obtained in the same manner as in Example 1 except that the composite particles were used. Table 2 shows the evaluation results of hiding properties.

Example 4
[Preparation of flat resin particles]
(first stage)
In a polymerization vessel equipped with a stirrer and a thermometer, 1700 g of deionized water in which 0.90 g of sodium p-styrenesulfonate (manufactured by Tosoh Corporation) was dissolved was added. A monomer mixture composed of 300 g of styrene and 3.2 g of α-methylstyrene dimer prepared in advance was charged into the obtained solution, and heated to 80 ° C. while purging with nitrogen under stirring. After maintaining the internal temperature at 80 ° C. and adding 40 g of deionized water in which 3.0 g of potassium persulfate was dissolved as a polymerization initiator, the monomer mixture was polymerized over 17 hours. The average particle diameter of the polymer particles (seed particles) in the obtained emulsion was 0.19 μm.

(Second stage)
Particles were obtained in the same manner as in Example 1 except that 111 g of the emulsion (solid content: 15% by weight) obtained in the first stage was used. When the obtained particles were observed, the particles had a bottom diameter (D) of 0.7 μm, a thickness (H) from the bottom to the top of the convex surface of 0.43 μm, and a maximum inner diameter of 0 at the center of the bottom of the particles. It was flat resin particles having a recess of 21 μm ((D / H) = 1.6).

[Production of spherical composite particles]
Composite as in Example 1 except that the inorganic particles were changed to 150 g of Snowtex C30 (manufactured by Nissan Chemical Industries, Ltd .: colloidal silica, particle size: 0.01-0.02 μm, 30% as solid content of silica). Particles were obtained. The obtained composite particles had an average particle diameter of 35 μm and had a spherical shape. The obtained composite particles were subjected to a sensory test. The results are shown in Table 1. FIG. 3 shows an electron micrograph of spherical composite particles.
[Production of powder foundation]
A powder foundation was obtained in the same manner as in Example 1 except that the composite particles were used. Table 2 shows the evaluation results of hiding properties.

Example 5
[Preparation of flat resin particles]
Flat resin particles were obtained in the same manner as in Example 1.
[Production of spherical composite particles]
Composite particles were obtained in the same manner as in Example 1 except that the inorganic particles were changed to 50 g of Cicilia 446 (Fuji Silysia, Inc .: silica, particle diameter: 4.5 μm). The obtained composite particles had an average particle diameter of 33 μm and had a spherical shape. The obtained composite particles were subjected to a sensory test. The results are shown in Table 1.
[Production of powder foundation]
A powder foundation was obtained in the same manner as in Example 1 except that the composite particles were used. Table 2 shows the evaluation results of hiding properties.

Comparative Example 1
[Production of resin particles]
(first stage)
Same as Example 1.
(Second stage)
A polymerization vessel equipped with a stirrer and a thermometer was charged with 750 g of deionized water in which 3.0 g of sodium dodecylbenzenesulfonate was dissolved, and a monomer composed of 250 g of styrene and 12.5 g of divinylbenzene prepared beforehand. A mixture and a mixed solution in which 1.2 g of benzoyl peroxide as a polymerization initiator were dissolved were added. Then, the mixed solution was T.P. A dispersion was prepared by stirring with a K homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).

Furthermore, 41 g of the emulsion obtained in the first stage was added to the dispersion, and the mixture was stirred at 30 ° C. for 2 hours to allow the seed particles to absorb the dispersion. Next, the polymer mixture was polymerized by heating the obtained mixture under a nitrogen stream at 75 ° C. for 12 hours, and then cooled to room temperature (about 25 ° C.). The obtained suspension was oven-dried at 70 ° C., and the obtained particles were observed with a scanning electron microscope. As a result, they were spherical particles having an average particle diameter of 1.2 μm ((D / H) = 1).
[Production of composite particles]
Composite particles were obtained in the same manner as in Example 1. The obtained composite particles had an average particle diameter of 32 μm and had a spherical shape. The obtained composite particles were subjected to a sensory test. The results are shown in Table 1.
[Production of powder foundation]
A powder foundation was obtained in the same manner as in Example 1 except that the composite particles were used. Table 2 shows the evaluation results of hiding properties.

Comparative Example 2
[Preparation of flat resin particles]
Flat resin particles were obtained in the same manner as in Example 1.
[Production of composite particles]
Composite particles were produced in the same manner except that the inlet temperature during spray drying was changed to 245 ° C and the outlet temperature was changed to 120 ° C. The obtained composite particles had an average particle size of 34 μm. As a result of observing the obtained composite particles with an electron microscope (SEM), the composite particles had a spherical shape, but the fusion between the flat resin particles was larger than that in Example 1. The obtained composite particles were subjected to a sensory test. The results are shown in Table 1.

[Production of powder foundation]
A powder foundation was obtained in the same manner as in Example 1 except that the composite particles were used. Table 2 shows the evaluation results of hiding properties.

  From Table 1, the spherical composite particles of the examples have higher evaluation than the comparative examples in terms of smoothness, soft feeling, elongation, and their total points.

  From Table 2, the powder foundation containing the spherical composite particles of the examples can effectively conceal the presence or absence of veins on the skin as compared with the comparative example.

D Diameter H Thickness d Maximum inner diameter

Claims (8)

A plurality of inorganic particles and a plurality of flat resin particles selected from styrene resin particles, (meth) acrylic resin particles, and mixed particles of both resin particles,
The inorganic particles have an average particle size of 1 μm or less;
The flat resin particle has a circular outer shape in the figure projected so as to maximize the area, and the outer shape of a cross section in a direction orthogonal to the direction of the projection is formed by a convex portion and a concave portion corresponding to the convex portion. Have
The circular shape has a diameter (D) of 6 μm or less;
The convex portion has a thickness (H) at which the ratio (D / H) of the thickness (H) to the diameter (D) is 1.4 or more,
The spherical composite particle, wherein the concave portion has a maximum inner diameter (d) of 0.1 μm or more.   The spherical composite particle according to claim 1, wherein the spherical composite particle has an average particle diameter of 1 to 150 μm.   The spherical composite particles according to claim 1, wherein the flat resin particles have the diameter (D) that is 0.1 to 600 times the average particle diameter of the inorganic particles.   The spherical composite particle according to any one of claims 1 to 3, wherein the circular shape has a diameter of 0.5 to 6 µm, and the ratio (D / H) is 1.4 to 4.   The spherical composite particles according to any one of claims 1 to 4, wherein the inorganic particles are selected from titanium oxide, zinc oxide, and iron oxide.   The spherical composite particles according to any one of claims 1 to 5, wherein the spherical composite particles are particles containing 5 to 99 parts by weight of the inorganic particles with respect to 100 parts by weight of the flat resin particles. A method for producing the spherical composite particles according to any one of claims 1 to 6,
The spherical composite particles are obtained by spray-drying a dispersion in which the flat resin particles and the inorganic particles are dispersed in an aqueous medium.
The method for producing spherical composite particles, wherein the spray drying is performed under conditions of a dispersion liquid inlet temperature of a spray dryer of 90 to 230 ° C and a spherical composite particle outlet temperature of a spray dryer of 40 to 120 ° C.   A cosmetic comprising 1 to 80% by weight of the spherical composite particles according to any one of claims 1 to 6.