JP5165856B2 - Anisotropic particles, production method thereof, and cosmetics containing anisotropic particles - Google Patents

Description

  The present invention relates to anisotropic particles, and more particularly to improving the anisotropic performance of the anisotropic particles.

  In recent years, with the rapid development of the industry, the size of nano-order size control and particle design according to applications has increased for particles used in electronics / information, bio / medical, and fine chemical fields. Yes. In order to impart multi-functionality to particles, compounding of substances with different properties is generally used. In particular, so-called anisotropic particles in which a plurality of substances having different properties are present separately in one particle are unique. It is attracting attention because of its natural properties.

  One method of using anisotropic particles is a powder emulsifier. The use of powders as emulsifiers has already been carried out by Levine et al., And it has been reported that surface-treated fine hydrophobic silica stabilizes surfactant-free dispersions (eg, non-surfactant). (See Patent Document 1).

In addition, a powder having both a hydrophilic part and a hydrophobic part that has been partially treated with alkylsilane on the particle surface has been developed (see, for example, Non-Patent Document 2). In this method, silica particles with a particle size of 250-660 nm with a small amount of water added are suspended in a toluene solution containing n-octadecyltrimethoxysilane, centrifuged, and dried, so that the octadecyl group is modified on the entire particle surface. This is a technique for obtaining a semi-hydrophobic particle.
However, this hydrophobic silica is in a state where hydrophilic portions and hydrophobic portions are scattered over the entire surface of the silica particles. If a hydrophilic property is imparted to one surface of the powder particles and a hydrophobic property is imparted to the other surface, and the hydrophilic portion and the hydrophobic portion can be separated, a powder emulsifier with improved surface activity is expected. .

As a further application example of anisotropic particles, a rotating bead for electronic paper can be considered by imparting a property of + to one side of anisotropic particles and a property of-to the other side. That is, if one side of an anisotropic particle is white, the other side is black, and the charges on both spherical surfaces of the particle are different, the black-and-white orientation can be controlled when the particle is placed in an electric field, and rewritable electrons Realization of paper is realized.
In addition, with respect to anisotropic particles imparted with the property of + on one side and-on the other side, MR fluid with increased viscosity that occurs when a magnetic field is applied is applied to car brakes, clutches, machine lubricants, etc. Application is also possible.

A surface anisotropic polymer particle is known as a specific example in which different performance is given to the surface of one side hemisphere of the particle and the surface of the other side hemisphere (see, for example, Patent Document 1). This is because the protein (for example, immunoglobulin G (human IgG)) to be modified is uniformly adsorbed on the surface of the substrate (polystyrene plate or the like), and then one side of the polymer particle is brought into contact with the protein. Only one side of the polymer particles is modified with human IgG, and the other side has a hydrophilic surface.
However, the method for synthesizing the above-mentioned surface anisotropic polymer particles is complicated and yield is relatively low. Moreover, the substance modified on the polymer surface was sparsely present in the hemisphere portion.
Therefore, in the prior art, it has been difficult to coat a substance to be finely modified on the surface of one side of the particle.
Japanese Patent No. 3567269 Colloids andSurfaces, Vol.38, 325-343 (1989) Journal of American Chemical Society, 2005, 127, 6271-6275

  The present invention has been made in view of the above-mentioned circumstances, and a first object thereof is to provide anisotropic particles whose powder particle surfaces are densely coated locally with a hydrophilic substance. The second object is to provide an efficient production method of the anisotropic particles using a water-in-oil emulsification technique.

As a result of intensive studies by the present inventors, after preparing a water-in-oil powder emulsified base containing a hydrophobic base powder, an oil component, and an aqueous phase, the particle interface between the inner aqueous phase and the hydrophobic base powder By coating the surface of the particles corresponding to the above with a hydrophilic substance prepared in the inner aqueous phase, it is possible to obtain anisotropic particles in which the particle surface is unevenly distributed in one region and densely coated with the hydrophilic substance. As a result, the present invention has been completed.
That is, the present invention provides anisotropic particles characterized in that the surface of the particles of the hydrophobic group powder is densely coated with a hydrophilic substance unevenly distributed in one region .

In anisotropic particles according to the present invention, the hydrophobic group powder is silicone resin powder, acrylic resin powder, polyethylene resin powder, a polystyrene resin powder, that is one or more selected nylon resin Powder or al Features.
Further, in the anisotropic particles according to the present invention, it is preferable that the hydrophobic group powder is a silicone resin powder.
In the anisotropic particles according to the present invention, the hydrophilic substance is one or more selected from silicon oxide, aluminum oxide, titanium oxide, iron oxide, and zinc oxide.

In the anisotropic particles according to the present invention, the hydrophobic group powder has an average particle size of 0.01 to 100 μm.
In the anisotropic particles according to the present invention, the hydrophobic group powder has a spherical particle shape.
A cosmetic comprising the emulsifier according to the present invention is provided.
Moreover, the emulsion composition which mix | blended the emulsifier concerning the said invention is provided.

The present invention comprises a step of obtaining a water-in-oil powder emulsified base by mixing and stirring a base powder, an oil, and an aqueous phase (1) containing a raw material component of a hydrophilic substance that covers the base powder ; An aqueous phase (2) containing a catalyst for converting the raw material component of the hydrophilic substance into a hydrophilic substance is added to the water-in-oil powder emulsified base, A step of preparing one or more hydrophilic substances selected from silicon oxide, aluminum oxide, titanium oxide, iron oxide, and zinc oxide; and the hydrophilic substance at the interface between the inner aqueous phase and the particles of the base powder. And a method of producing anisotropic particles comprising a step of finely and locally coating the surface of the particles of the base powder with the hydrophilic substance.
In the method for producing anisotropic particles according to the present invention, the blending ratio (W / O ratio) of the water phase (water phase (1) + water phase (2)) and oil is 10/90 to 70/30. It is characterized by being.
In the said manufacturing method, the mixture ratio of base powder is 0.1 to 20% with respect to the total amount of an oil component and a water phase (Aqueous phase (1) + Aqueous phase (2)), It is characterized by the above-mentioned.

In the production method, the aqueous phase (1) comprises tetraethyl orthosilicate, sodium silicate, aluminum chloride, aluminum sulfate, titanium tetrachloride, titanyl sulfate, iron chloride, iron nitrate, iron sulfate, zinc chloride, γ-aminopropyltri It includes one or more selected from ethoxysilane and polyether-modified trialkoxysilane.
Further, tetraethyl orthosilicate, sodium silicate, aluminum chloride, aluminum sulfate, titanium tetrachloride, titanyl sulfate, iron chloride, iron nitrate, iron sulfate, zinc chloride, γ-aminopropyltriethoxy contained in the aqueous phase (1) The blending ratio of one or more substances selected from silane and polyether-modified trialkoxysilane is 0.1 to 20% with respect to the total amount of oil and water phase.
In the production method, the aqueous phase (2) contains a catalyst for preparing a hydrophilic substance.

According to the present invention, since the surface of the hydrophobic group powder is unevenly distributed and densely coated in one region with the hydrophilic substance, both the performance of the hydrophobic group powder itself and the hydrophilic performance are effectively obtained. Anisotropic particles that can be exhibited can be obtained. And this anisotropic particle can function as a powder emulsifier excellent in surface active ability, when the emulsion which mix | blended it is prepared.
Moreover, according to the method for producing anisotropic particles according to the present invention, it is possible to efficiently provide the anisotropic particles.

Hereinafter, embodiments of the present invention will be described in more detail.
Base Powder In the present invention, the hydrophobic base powder constituting the anisotropic particles is appropriately selected depending on the properties of the desired anisotropic particles. Specifically, silicone resin powder, polyacrylate powder , polycarbonate powder, polyvinyl chloride powder, polyamide powder, polyethylene powder, polymer powders of polystyrene powder, etc., the alumina powder, titanium oxide powder, iron oxide powder, boron nitride powder, inorganic powder, and the like talc powder. Of these, silicone resin powder is particularly preferably used in the present invention.

In addition, the base powder may have been processed on a part or all of its surface. Examples of the treatment method include silicone treatment, fluorine treatment, fatty acid treatment, and cation treatment.
Since the base powder used in the present invention is mixed and stirred together with the oil and the water phase to form a water-in-oil powder emulsified base, the particle size of the base powder is stable compared to the water-in-oil powder emulsified base. Although it will not specifically limit if it can be prepared, It is preferable that it is 0.01-100 micrometers.
In addition, examples of the particle shape of the base powder used in the present invention include a spherical shape, a plate shape, a lump shape, and a cylindrical shape, and the spherical shape is preferable from the viewpoint of the uniformity of coating with a novel substance on the particle surface. .

Hydrophilic substance In the present invention, specific examples of the hydrophilic substance covering the surface of the base powder include the following.
As inorganic substances, silicon oxide obtained from tetraethyl orthosilicate, sodium silicate, etc., aluminum oxide obtained from aluminum chloride, aluminum sulfate, etc., titanium oxide obtained from titanium tetrachloride, titanyl sulfate, etc., iron chloride, iron nitrate, iron sulfate And zinc oxide obtained from iron oxide, zinc chloride and the like.
Examples of organic substances include substances having hydrophilic groups such as amino groups, carboxyl groups, hydroxyl groups, sulfone groups, ether groups, and silicone substances such as γ-aminopropyltriethoxysilane and polyether-modified trialkoxysilane. Can be mentioned.
The anisotropic particles according to the present invention may be coated with one or more of the above hydrophilic substances.

  FIG. 1 schematically shows the configuration of anisotropic particles according to the present invention. As shown in FIG. 1, in the anisotropic particles, a local surface on one side of a base powder such as a silicone resin is coated with a hydrophilic substance such as silica. In the present invention, the coating with the hydrophilic substance is characterized in that it is made dense in the local coating portion. “Densely” means a state in which the distance between particles of the hydrophilic substance to be approximated is 1 μm or less, and more preferably 200 nm or less. This distance is calculated from an SEM micrograph, for example. When the distance between the particles of the approximate hydrophilic substance is 200 nm or less, the hydrophilic substance is present very smoothly in the local coating portion, and the function as anisotropic particles is more preferably exhibited. There is.

Further, “ distributed unevenly in one region ” does not mean that it is scattered over the entire surface of the base powder, and is continuous on a part of the one-sided hemisphere surface, or on the entire one-sided hemispherical surface or on the one-sided hemispherical surface or more. Means part.
Furthermore, the coating state of the anisotropic particles according to the present invention can also be expressed by the ratio of the coating portion area by the hydrophilic substance to the surface area of the base powder, that is, the coating rate. The coverage is calculated by the following measuring method.
Measuring instrument: SEM (inspection electron microscope) (manufactured by Hitachi, Ltd.)
Measurement method: The surface of anisotropic particles (100 particles) was observed with an SEM, the particle diameter of the base powder and the area of the coating portion were measured, and the average coverage was calculated.
In the present invention, the average coverage is 30 to 70%.

Next, the manufacturing method of the anisotropic particle concerning this invention is demonstrated.
The method for producing anisotropic particles according to the present invention includes a base powder, an oil component, and a water phase (1) containing a raw material component of a hydrophilic substance that coats the base powder. Obtaining an emulsifying base;
An aqueous phase (2) containing a catalyst for converting a raw material component of a hydrophilic substance into a hydrophilic substance is added to the water-in-oil powder emulsified base, and in the inner aqueous phase of the water-in-oil powder emulsified base A step of preparing a hydrophilic substance;
The hydrophilic substance gathers at the interface between the inner aqueous phase and the particles of the base powder, and the particle surface of the base powder is unevenly distributed in one area and densely coated with the hydrophilic substance. To do.
The structure of the water-in-oil type powder emulsified base prepared in the above manufacturing method is shown in FIG.
In the figure, the oil phase contains the oil component, and the water phase contains water, a raw material component of a hydrophilic substance covering the base powder, and a catalyst used for converting the raw material component into a hydrophilic substance.
First, components used in the production process will be described in detail below.

Oil content As the oil component used when producing the anisotropic particles according to the present invention, an oil component which is liquid at room temperature is preferably used. Specifically, silicone oil such as methylpolysiloxane and methylphenylpolysiloxane, hydrocarbon oil such as liquid paraffin, isoparaffin, squalane and squalene, isopropyl myristate, 2-octyldecyl myristate, 2-octyldecyl myristate, Such as cetyl 2-ethylhexanoate, 2-ethylhexyl 2-ethylhexanoate, isononyl 2-ethylhexanoate, 2-ethylhexyl palmitate, 2-hexyldecyl stearate, ethyl isostearate, isopropyl isostearate, 2-ethylhexyl salicylate, etc. Examples include fats and oils such as ester oil, olive oil, camellia oil, macadamia nut oil and castor oil, and organic solvents such as benzene, toluene and hexane.
In the present invention, one or more of the above oils may be used.

The aqueous phase (1) to be used in producing the anisotropic particles according to the aqueous phase present invention is characterized in that it comprises a raw material components of the hydrophilic material coating the water and based powder.
Water corresponds to a main component for forming a water-in-oil type powder emulsified base through the base powder when the oil and the base powder are mixed and stirred.
In addition, the above-mentioned “raw material component of the hydrophilic substance” includes the aforementioned tetraethyl orthosilicate, sodium silicate, aluminum chloride, aluminum sulfate, titanium tetrachloride, titanyl sulfate, iron chloride, iron nitrate, iron sulfate, zinc chloride, γ -Corresponds to one or more selected from aminopropyltriethoxysilane, polyether-modified trialkoxysilane and the like.

The aqueous phase (2) used when producing anisotropic particles according to the present invention is characterized in that it contains a catalyst used for converting the raw material component of the hydrophilic substance into a hydrophilic substance.
The aqueous phase (1) and / or the aqueous phase (2) can be blended with ethanol in order to solubilize the “raw material component of the hydrophilic substance” in water. When ethanol is blended in the water phase, the blending amount of ethanol is preferably 40% or less with respect to the total amount of water phase (water phase (1) + water phase (2)). If the blending amount of ethanol exceeds 40% with respect to the total amount of the aqueous phase, it becomes difficult to form a water-in-oil type powder emulsified base, and anisotropic particles according to the present invention may not be obtained, which is not preferable. .

When the aqueous phase (2) containing the “catalyst” is added to the water-in-oil type powder emulsified base formed by the base powder, the oil component, and the aqueous phase (1) and mixed and stirred, the aqueous phase (1) In the inner aqueous phase, the “raw material component of the hydrophilic substance” present in the aqueous phase and the catalyst present in the aqueous phase (2) coexist. Therefore, the catalyst serves to promote a reaction for converting the “raw material component of the hydrophilic substance” into the hydrophilic substance. Details of the catalyst will be described later.
In the method for producing anisotropic particles according to the present invention, the mixing ratio (W / O ratio) of the water phase (water phase (1) + water phase (2)) and oil is 10/90 to 70/30. Is preferred. In preparing the water-in-oil type powder emulsifying base, such a blending ratio is preferable. When the W / O ratio is less than 10/90, the amount of powder required for emulsification is small and the production efficiency is significantly reduced. On the other hand, when the W / O ratio is greater than 70/30, it is difficult to prepare a stable water-in-oil type emulsion base.

Catalyst The catalyst contained in the aqueous phase (2) is not particularly limited as long as the “hydrophilic substance raw material component” is a substance that can be converted into a hydrophilic substance, but it depends on the hydrophilic material used. Are appropriately selected. Specifically, when tetraethyl orthosilicate is used as the “raw material component of the hydrophilic substance”, hydrochloric acid or ammonia water is used, and when iron oxide is used, sodium hydroxide or an aqueous solution thereof is used.
Further, the blending amount of the catalyst is appropriately determined as an amount necessary for the “raw material component of the hydrophilic substance” to be converted into the hydrophilic substance.

In the method for producing anisotropic particles according to the present invention, the blending amount of the base powder is 0.1 to 20% with respect to the total amount of the oil and the water phase (water phase (1) + water phase (2)). Preferably it is. If it is less than 0.1%, the amount is not sufficient for the preparation of a powder emulsifying base, and if it exceeds 20%, dispersibility in the oil phase is deteriorated.
Moreover, it is suitable that the compounding quantity of the raw material component of a hydrophilic substance is 0.1 to 20% with respect to the total amount of an oil component and a water phase (Aqueous phase (1) + Aqueous phase (2)). If it is less than 0.1%, the amount is not sufficient to cover the surface of the base powder, and even if it exceeds 20%, no improvement in the effect due to the increase is observed.

Below, an example of the manufacturing method of the anisotropic particle concerning this invention is shown.
Production Example based powder, (trade name Tospearl 105 GE Toshiba Silicones Co., Ltd.) Spherical silicone resin powder an average particle diameter of 0.5μm 2 parts by weight, were charged into liquid paraffin 58 parts by weight, dispersed with an ultrasonic After that, the dispersion is obtained by stirring for 1 minute using a disper.
Subsequently, 0.74 parts by weight of tetraethyl orthosilicate, 10 parts by weight of ethanol, and 15 parts by weight of ion exchange water as a raw material component of the hydrophilic substance are gradually added to the dispersion while stirring with a stirrer. After stirring for 1 minute, a water-in-oil powder emulsified base is obtained.
Further, while stirring the water-in-oil type powder emulsifying base with a stirrer, 10 parts by weight of 25% aqueous ammonia and 5 parts by weight of ion-exchanged water were gradually added as a catalyst, and the mixture was stirred at room temperature for 6 hours. Mix and stir.
Thereafter, centrifugation is performed, the powder component is taken out, washed with ethanol, and heated and dried at 105 ° C. for 12 hours to isolate anisotropic particles whose surface on one side of the silicone resin powder is densely coated with silica. It is.

Principle (i) A water-in-oil powder emulsified base stabilized by a base powder in the step of obtaining a water-in-oil powder emulsified base by mixing and stirring the base powder, oil, and aqueous phase (1). An agent is prepared. As a result, the oil component forms an oil phase that is an outer phase, while the aqueous phase (1) containing the raw material component of the hydrophilic substance forms an inner aqueous phase of the powder emulsified base.
(Ii) Next, when the water phase (2) containing a catalyst is added while stirring the water-in-oil type powder emulsified base prepared in the above step, the water phase (2) enters the inner water phase and enters the water. To be mixed with phase (1). When the catalyst coexists with the raw material component of the hydrophilic substance, the hydrophilic substance is synthesized in the inner aqueous phase. The aqueous phase (2) containing the catalyst is added after the preparation of the water-in-oil type emulsified base using the aqueous phase (1) as the inner aqueous phase, whereby one surface of the inner powder on the inner water phase side is added. A hydrophilic substance aggregates in part, all, or more than one side surface, and the characteristic covering state of the anisotropic particle concerning this invention is obtained.

In addition, the one side surface of the base powder particles on the inner aqueous phase side is sufficiently covered with the inner aqueous phase where the hydrophilic substance is present, so that it is densely coated. Furthermore, all of the base powder particles forming the emulsified state are efficiently coated with the hydrophilic substance. At this point, anisotropic particles according to the present invention are formed.
After one side surface of the base powder particles facing the inner water phase has sufficiently reacted with the hydrophilic substance, the water-in-oil emulsified state is broken by a centrifuge or the like, and only the base powder is recovered and dried. Thus, the anisotropic particles according to the present invention are isolated.
In the production of anisotropic particles according to the present invention, the stirring method employed for preparing the water-in-oil type powder emulsifying base can be the method usually used for preparing the emulsion composition. . Specific examples include a stirrer, a propeller mixer, a disper, a homomixer, and a homogenizer.

It is possible to use anisotropic particles that written to the present invention as emulsifying bases. Examples of the emulsion composition prepared by such use include water-in-oil, oil-in-water, and polyhydric alcohol-in-oil emulsions, multiple emulsions, and the like.
The cosmetic according to the present invention is excellent in an emulsified state by including the anisotropic particles. Moreover, it can apply with respect to a wide range of cosmetics irrespective of the kind of oil depending on the specific coating state of the hydrophilic substance of the anisotropic particles.

The content of the anisotropic particles contained in the cosmetic according to the present invention is not particularly limited as long as the effect of the present invention can be obtained, and can be appropriately adjusted and used. .1 to 20% by mass. If it is less than 0.1% by mass, the effects of the present invention may not be exhibited, and if it exceeds 20% by mass, it may be unfavorable in terms of formulation.
The cosmetics according to the present invention include components used in ordinary cosmetics, for example, moisturizers, antioxidants, oily components, ultraviolet absorbers, emulsifiers, surfactants, within the range that does not impair the effects of the present invention. , Thickeners, alcohols, powder components, color materials, aqueous components, water, various skin nutrients, and the like can be appropriately blended as necessary.

  Cosmetics according to the present invention include, for example, ointments, creams, emulsions, lotions, packs, foundations, blushers, eye shadows, white powders, lipsticks, bath preparations, oil blotting paper, paper powder, body powders, baby powders, powder sprays, etc. Any form can be applied as long as it is used for conventional cosmetics, and the dosage form is not particularly limited.

EXAMPLES Hereinafter, although an Example is given concretely and this invention is demonstrated in more detail, this invention is not limited by these Examples.
In the present invention, the average particle diameter of anisotropic particles was measured as follows.
The particles were observed with a scanning electron microscope, and the average value of the particle sizes of 100 randomly extracted particles was defined as the average particle size.

First, an example of producing anisotropic particles according to the present invention is shown below.
Production Example 1
2 parts by weight of spherical silicone resin powder having an average particle size of 4.5 μm (trade name Tospearl 145A manufactured by GE Toshiba Silicone Co., Ltd.) was charged into 58 parts by weight of dimethylpolysiloxane, dispersed with ultrasonic waves, and then dispersed with a disper. The mixture was stirred for a minute to obtain a dispersion.
Subsequently, 0.74 parts by weight of tetraethyl orthosilicate, 10 parts by weight of ethanol, and 15 parts by weight of ion-exchanged water were gradually added to the dispersion while stirring with a stirrer, followed by stirring for 1 minute, A water-in-water powder emulsifying base was obtained.

Further, while stirring the water-in-oil type powder emulsifying base with a stirrer, 10 parts by weight of 25% aqueous ammonia and 5 parts by weight of ion-exchanged water were gradually added as a catalyst, and the mixture was stirred at room temperature for 6 hours. The mixture was stirred.
Thereafter, centrifugal separation was performed, the powder component was taken out, washed with ethanol, and heated and dried at 105 ° C. for 12 hours to obtain anisotropic particles in which one side surface of the silicone resin powder was coated with silica.
Average particle size: 4.5 μm

Production Example 2
2 parts by weight of spherical silicone resin powder having an average particle size of 4.5 μm (trade name Tospearl 145A manufactured by GE Toshiba Silicone Co., Ltd.) was charged into 58 parts by weight of dimethylpolysiloxane, dispersed with ultrasonic waves, and then dispersed with a disper. The mixture was stirred for a minute to obtain a dispersion.
Subsequently, 0.172 parts by weight of iron (II) chloride tetrahydrate, 0.468 parts by weight of iron (III) chloride hexahydrate, and 30 parts by weight of ion-exchanged water were added to the dispersion. While stirring with a stirrer, the mixture was stirred for 1 minute, and then a water-in-oil powder emulsified base was obtained.
Further, while stirring the water-in-oil powder emulsified base with a stirrer, 10 parts by weight of an aqueous 1N sodium hydroxide solution as a catalyst was gradually added, and the mixture was stirred at room temperature for 6 hours.
Thereafter, centrifugal separation was performed, the powder component was taken out, washed with ethanol, and heated and dried at 105 ° C. for 12 hours to obtain anisotropic particles in which one side surface of the silicone resin powder was coated with iron oxide.
Average particle size: 4.5 μm

Production Example 3
2 parts by weight of polymethyl methacrylate resin powder having an average particle size of 9 μm (trade name: Matsumoto Microsphere M-306, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) is placed in 58 parts by weight of liquid paraffin and dispersed with ultrasonic waves. And stirred for 1 minute to obtain a dispersion.
Subsequently, 0.41 part by weight of sodium silicate and 30 parts by weight of ion-exchanged water were gradually added to the dispersion while stirring with a stirrer, and after stirring for 1 minute, water-in-oil powder emulsification A base was obtained.
Furthermore, while stirring the water-in-oil type powder emulsifying base with a stirrer, 6.5 parts by weight of an aqueous phase (2) of 1M hydrochloric acid was gradually added as a catalyst, and mixed and stirred at room temperature for 6 hours.
Thereafter, centrifugal separation was performed, the powder component was taken out, washed with ethanol, and heated and dried at 105 ° C. for 12 hours to obtain anisotropic particles in which one side surface of the polymethyl methacrylate resin powder was coated with silica.
Average particle size: 9μm

Production Example 4
2 parts by weight of a spherical silicone resin powder having an average particle size of 4.5 μm (trade name Tospearl 145A manufactured by GE Toshiba Silicone Co., Ltd.) is charged into 38 parts by weight of dimethylpolysiloxane, dispersed with ultrasonic waves, and then dispersed with a disper. The mixture was stirred for a minute to obtain a dispersion.
Subsequently, 0.172 parts by weight of iron (II) chloride tetrahydrate, 0.468 parts by weight of iron (III) chloride hexahydrate, and 25 parts by weight of ion-exchanged water are added to the dispersion. While stirring with a stirrer, the mixture was stirred for 1 minute, and then a water-in-oil powder emulsified base was obtained.

Further, while stirring the water-in-oil powder emulsifying base with a stirrer, 10 parts by weight of 25% aqueous ammonia and 15 parts by weight of ion-exchanged water were gradually added as a catalyst, and the mixture was stirred at room temperature for 6 hours. The mixture was stirred.
Thereafter, centrifugal separation was performed, the powder component was taken out, washed with ethanol, and heated and dried at 105 ° C. for 12 hours to obtain anisotropic particles in which one side surface of the silicone resin powder was coated with iron oxide .

Production Example 5
2 parts by weight of a spherical silicone resin powder having an average particle size of 4.5 μm (trade name Tospearl 145A manufactured by GE Toshiba Silicone Co., Ltd.) is charged into 38 parts by weight of dimethylpolysiloxane, dispersed with ultrasonic waves, and then dispersed with a disper. The mixture was stirred for a minute to obtain a dispersion.
Subsequently, 20 parts by weight of an aqueous 1M titanium chloride solution (1) was gradually added to the dispersion while stirring with a stirrer and stirred for 1 minute to obtain a water-in-oil powder emulsified base.
Further, while stirring the water-in-oil powder emulsified base with a stirrer, 20 parts by weight of an aqueous 1M sodium hydroxide solution (2) was gradually added as a catalyst, and mixed and stirred at room temperature for 6 hours.
Thereafter, centrifugation was performed, the powder component was taken out, washed with ethanol, and heated and dried at 105 ° C. for 12 hours to obtain anisotropic particles in which one side surface of the silicone resin powder was coated with titanium oxide.
Average particle size: 4.5 μm

As a result of observing the coated state of the anisotropic particles synthesized in Production Examples 1 to 5 with an electron microscope, it was confirmed that the spherical particles were continuously and densely coated on one surface of the base powder. It was done. FIG. 3 shows a micrograph of anisotropic particles obtained in Production Example 1 in which the silicone resin powder is coated with silica. FIG. 4 shows a micrograph of anisotropic particles obtained in Production Example 2 in which the silicone resin powder is coated with iron oxide.
In addition, it was confirmed that the anisotropic particles obtained in Production Example 2 were attracted when the anisotropic particles in which the silicone resin powder was coated with iron oxide were brought close to the magnet, so that the anisotropic particles had magnetism. It was.

Next, a test for confirming the surface activity as a powder emulsifier was carried out using the anisotropic particles obtained in Production Example 2. The test method and evaluation method are as follows.
Test method In the composition shown in Table 1 below, the sample powder is added to the oil, dispersed with a disper for 1 minute, and then gradually added with stirring with a stirrer to form a water-in-oil (W / O) emulsion. Got.
In addition, all the numerical values described in Table 1 below are parts by weight.

Evaluation Method / Evaluation Criteria The emulsified state of each emulsion obtained by the above test method was determined by observation and visual observation with a laser microscope.
○: The particle size distribution is narrow, and spherical emulsified particles form an emulsified layer.
(Triangle | delta): The distribution of a particle diameter is wide and the pseudospherical emulsification particle | grain forms the emulsion layer.
X: The emulsified layer is hardly formed.

* 1: Product name Tospearl 145A GE manufactured by Toshiba Silicone Co., Ltd.

As is apparent from Table 1 above, when emulsification was attempted using a silicone resin having no anisotropy and relatively high hydrophobicity, inorganic properties such as cetyl 2-ethylhexanoate and tripropylene glycol dineopentanoate were used. It was not possible to obtain a uniform W / O emulsion composed of a strong oil and water (Test Examples 4 and 5).
On the other hand, when anisotropic particles obtained in Production Example 2 in which one side local portion of the surface of the silicone resin powder is densely and continuously coated with iron oxide are used, uniform W for various oils / O emulsion was formed (Test Examples 1 to 3). This is because the iron oxide part showing hydrophilicity and the relatively hydrophobic silicone part are separated on the particle spherical surface, so the iron oxide part is preferentially oriented on the water side and the silicone part is preferentially oriented on the oil side. However, it is judged that the W / O emulsion could be formed when various oils were used.

Furthermore, the example of the composition which mix | blended the anisotropic particle concerning this invention is shown below.
W / O cream (1) Cyclomethicone 28.4% by mass
(2) Liquid paraffin 5.0
(3) Benton 10.0
(4) Anisotropic particles obtained in Production Example 1 3.5
(5) Propylparaben 0.1
(6) Glycerin 3.0
(7) Methylparaben 0.2
(8) Purified water residue (production method)
While stirring at a temperature of 25 ° C., the anisotropic particles of (4) Production Example 1 are dispersed in the oily components of components (1), (2), and (5), and components (6) to (8) are dispersed therein. Was poured, and then (3) was added to obtain the desired W / O cream.

O / W sunscreen oil phase (1) Squalane 4.0% by mass
(2) Octyl methoxycinnamate 8.0
(3) Cyclopentadimethylsiloxane 5.0
(4) Fragrance 0.1
Water phase 1
(5) 1,3-butylene glycol 5.0
(6) Ethanol 2.0
(7) Anisotropic particles obtained in Production Example 3 3.0
(8) Purified water Appropriate amount of water phase 2
(9) Succinoglycan 0.2
(10) Glycerol 3.0
(11) L-arginine L-aspartate 0.01
(12) Edetate 0.05
(13) Methylparaben appropriate amount (14) Purified water Residue (Production method)
The aqueous phase 1 is heated to 70 ° C., dispersed with a mixer or ultrasonic waves, and then the uniformly dissolved aqueous phase 2 is added. Further, an oil phase heated to 70 ° C. is added and emulsified with an emulsifier. This was cooled to obtain the desired O / W sunscreen.

Dual-use foundation powder part (1) Silicone-treated talc 16.2% by mass
(2) Silicone-treated mica 40.0
(3) Silicone-treated titanium dioxide 15.0
(4) Silicone-treated ultrafine titanium dioxide 5.0
(5) Silicone-treated Bengala 1.0
(6) Silicone-treated yellow iron oxide 3.0
(7) Silicone-treated black iron oxide 0.2
(8) Zinc stearate 0.1
(9) Anisotropic particles of Production Example 2 5.0
(10) Ethylparaben Appropriate amount of oil phase (11) Squalane 4.0
(12) Solid paraffin 0.5
(13) Dimethylpolysiloxane 4.0
(14) Glycerin triisooctanoate 5.0
(15) Octyl methoxycinnamate 1.0
(16) Antioxidant (Vitamin E) Appropriate amount (17) Fragrance Appropriate amount (Manufacturing method)
(1) to (7) are pulverized and mixed with a pulverizer, and the remaining powder part is added and mixed well. The oil phase components (11) to (17) were uniformly blended into the powder part, and then pulverized and mixed with a pulverizer. Furthermore, it compression-molded through the sieve to the inside plate, and obtained the target amphibious foundation.

It is the figure which showed schematic structure of the anisotropic particle concerning this invention. It is the figure which showed schematic structure of the water-in-oil type powder emulsification base in the manufacture process of the anisotropic particle concerning this invention. It is a SEM electron micrograph of the anisotropic particle (manufacture example 1) concerning this invention. It is a SEM electron micrograph of the anisotropic particle (manufacture example 2) concerning this invention.

Explanation of symbols

1. Anisotropic particles2. 2. Base powder 3. hydrophilic substance synthesized in the inner aqueous phase 4. Water-in-oil emulsified base stabilized by base powder Aqueous phase 6. Oil phase

Claims (13)

Hydrophobic substances of one or more types selected from silicon oxide, aluminum oxide, titanium oxide, iron oxide, and zinc oxide are unevenly distributed in one region at a distance of 200 nm or less on the particle surface of the hydrophobic group powder. And an emulsifier composed of anisotropic particles having an average coverage of 30 to 70%. In emulsifier according to claim 1, and wherein the hydrophobic group powder is silicone resin powder, acrylic resin powder, polyethylene resin powder, a polystyrene resin powder, that is one or more selected nylon resin Powder or al Emulsifier.   The emulsifier according to claim 1 or 2, wherein the hydrophobic group powder is a silicone resin powder. The emulsifier according to any one of claims 1 to 3 , wherein the hydrophobic group powder has an average particle size of 0.01 to 100 µm. The emulsifier according to any one of claims 1 to 4 , wherein the hydrophobic group powder has a spherical particle shape. Cosmetics which mix | blended the emulsifier in any one of Claims 1-5 . The emulsion composition which mix | blended the emulsifier in any one of Claims 1-5 . A step of obtaining a water-in-oil powder emulsified base by mixing and stirring a hydrophobic base powder, an oil component, and an aqueous phase (1) containing a raw material component of a hydrophilic substance covering the base powder ;
An aqueous phase (2) containing a catalyst for converting the raw material component of the hydrophilic substance into a hydrophilic substance is added to the water-in-oil powder emulsion base, and the water-in-oil powder emulsion base is added to the inner aqueous phase of the water-in-oil powder emulsion base. A step of preparing one or more hydrophilic substances selected from silicon oxide, aluminum oxide, titanium oxide, iron oxide, and zinc oxide ;
An emulsifier comprising: a step in which the hydrophilic substance aggregates at an interface between the inner aqueous phase and the particles of the hydrophobic group powder, and the particle surface of the hydrophobic group powder is unevenly distributed in one region by the hydrophilic substance. Manufacturing method. The method for producing an emulsifier according to claim 8 , wherein the mixing ratio (W / O ratio) of the aqueous phase (aqueous phase (1) + aqueous phase (2)) and oil is 10/90 to 70/30. A method for producing an emulsifier. In the manufacturing method of the emulsifier of Claim 8 or 9 , the mixture ratio of hydrophobic group powder is 0.1-0.1 with respect to the total amount of an oil component and a water phase (Aqueous phase (1) + Aqueous phase (2)). The manufacturing method of the emulsifier characterized by being 20%. The method for producing an emulsifier according to any one of claims 8 to 10 , wherein the aqueous phase (1) is tetraethyl orthosilicate, sodium silicate, aluminum chloride, aluminum sulfate, titanium tetrachloride, titanyl sulfate, iron chloride, A method for producing an emulsifier, comprising one or more selected from iron nitrate, iron sulfate, zinc chloride, γ-aminopropyltriethoxysilane, and polyether-modified trialkoxysilane. The manufacturing method of an emulsifier according to claim 1 1, tetraethyl orthosilicate contained in the aqueous phase (1), sodium silicate, aluminum chloride, aluminum sulfate, titanium tetrachloride, titanyl sulfate, iron chloride, iron nitrate, sulfate The blending ratio of one or more substances selected from iron, zinc chloride, γ-aminopropyltriethoxysilane, and polyether-modified trialkoxysilane is an oil component and an aqueous phase (water phase (1) + water phase (2 )) With respect to the total amount of 0.1 to 20%. The method for producing an emulsifier according to any one of claims 8 to 12 , wherein the aqueous phase (2) contains a catalyst for preparing a hydrophilic substance.