JP2003335865A - Amphipathic particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide particles which can be blended with a water-base cosmetic and exhibits hydrophobicity on the skin, and an economical method for preparing it. <P>SOLUTION: Amphipathic particles provided have recesses on the surface. Cosmetics containing the particles are provided. The method for preparing the amphipathic particles comprises spraying a mixture of a thermoplastic resin, a hydrophilic compound and a surface active agent at a temperature above the melting point (or softening point) of the thermoplastic resin into a vapor phase. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle having a modified surface, which has good blendability with cosmetics, skin fixability and feel, and is useful for cosmetics, and a method for producing the same.

[0002]

2. Description of the Related Art Heretofore, spherical particles have been proposed which give a smooth feeling to the skin. In order to give a feeling of dryness and prevent the particles from falling off from the skin, it is desirable that the particle surface is hydrophobic. However, it is difficult to mix the surface-hydrophobic particles into a water-based cosmetic, for example, a lotion, and in many cases, it is mixed into an alcohol-based cosmetic. Alcohol-based cosmetics are very irritating to the skin, so care must be taken when blending them.Although it is possible to blend them by using a surfactant, the hydrophobicity of the particle surface will be impaired. Although it is possible to stabilize the dispersion with a thickener, the cohesiveness of the particles is not improved.

An object of the present invention is to provide particles which can be blended in an aqueous cosmetic composition and exhibit hydrophobicity on the skin, and an inexpensive production method thereof.

[0004]

The present invention is directed to the surface of particles,
Amphiphilic particles having a concave portion, a cosmetic material containing the same, and a mixture of a thermoplastic resin, a hydrophilic compound and a surfactant in a gas phase at a temperature higher than the melting point (or softening point) of the thermoplastic resin. And a method for producing amphipathic particles, which is sprayed onto.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION [Amphipathic particle] In the present invention, the amphipathic particle means a particle having both hydrophilicity and hydrophobicity, and the particle of the present invention has an amphipathic property. It can be confirmed that it can be uniformly dispersed in water and a solvent (hexane).

The amphiphilic particles of the present invention have an average particle size of 0.1 to 1 because they do not have a rough feeling or a squeaky feeling.
00 μm is preferable, and 0.3 μm to 40 μm is particularly preferable.

This average particle diameter is a weight average particle diameter measured at room temperature (20 ° C.) of an alcohol suspension of particles with a laser diffraction type particle size distribution measuring device (LA-910 manufactured by Horiba) (relative refraction). A rate of 1.2 was used).

The shape of the amphiphilic particles of the present invention is not particularly limited, but spherical particles are preferable because they have a good feel on the skin.

The particles of the present invention preferably have a concave portion on the surface, the inside of the concave portion is hydrophilic, and the particle surface is preferably hydrophobic. The presence of the concave portions on the particle surface can be confirmed by an optical microscope or an electron microscope. Further, the hydrophilicity in the recess can be confirmed by coloring the hydrophilic dye.

The number average diameter of the recesses is 1/1000 to 1 of the particle diameter from the viewpoint of enhancing the amphipathic property of the particles.
It is preferably / 2, and more preferably 1/100 to 1/2.

The number average diameter of the concave portions can be determined by observing the diameter of 10 particles arbitrarily selected by observing with an optical microscope or an electron microscope.

[Method for producing amphipathic particles] The amphipathic particles of the present invention contain a mixture of a thermoplastic resin, a hydrophilic compound and a surfactant at a temperature not lower than the melting point (or softening point) of the thermoplastic resin. It can be produced by spraying in the gas phase. The upper limit of the spraying temperature is preferably 200 ° C. or lower from the viewpoint of the thermal stability of the surfactant, hydrophilic compound and thermoplastic resin.

Specifically, first, an interface between a thermoplastic resin and a hydrophilic compound is mixed at a temperature above the melting point (or softening point) of the thermoplastic resin, preferably below the boiling point of the hydrophilic compound. An activator is added, and an emulsion is formed using a disperser such as a homomixer. At this time, the surfactant may be mixed with the hydrophilic compound at the same time.

The mixing ratio of the thermoplastic resin and the hydrophilic compound is 1 part by weight of the hydrophilic compound to 100 parts by weight of the thermoplastic resin.
To 1000 parts by mass is preferable, 10 to 100 parts by mass is more preferable, and 10 to 70 parts by mass is particularly preferable. When the amount of the hydrophilic compound is larger than that of the thermoplastic resin, the dispersion tends to be unstable. If the dispersion is stable, it becomes a W / O emulsion, and the recesses of the obtained amphiphilic particles become hydrophilic, and the particle surface becomes hydrophobic. The surface of the particles is preferably hydrophobic in order to obtain a dry feel as a cosmetic.

The amount of the surfactant can be appropriately determined according to the types and amounts of the hydrophilic compound and the thermoplastic resin, and is 0.1 based on 100 parts by weight of the total amount of the thermoplastic resin and the hydrophilic compound. Is preferably 50 parts by mass, 1
It is more preferably 10 parts by mass. Further, it is preferably 0.1 to 5 with respect to 100 parts by mass of the thermoplastic resin.
It is 0 part by mass, more preferably 1 to 10 parts by mass.

It is considered that the diameter of the recesses on the surface of the particles depends on the particle diameter of the emulsion of the mixture of the thermoplastic resin, the hydrophilic compound and the surfactant. Also, the particle size of the particles depends on the droplets when spraying. Therefore, the particle size of the emulsion is preferably 0.01 to 1000 μm, and is preferably 0.1 to 10 μm.
0 μm is more preferable, and it is even more preferable that it is smaller than the droplet when sprayed, and 1/1000 to 1 of the diameter of the droplet.
The range of / 2 is particularly preferable. In this case, the diameter of the recesses of the obtained amphiphilic particles is also 1/100 of the particle diameter.
It is considered to be in the range of 0 to 1/2. The diameter of the recess can be controlled by the shearing force during emulsification and the selection of the surfactant.

The molecular weight of the thermoplastic resin used in the present invention depends on the viscosity of the mixture of the thermoplastic resin and the hydrophilic compound,
Preferably, it should be 600 mPa · s or less, so that
0 to 20,000 is preferable, 1,000 to 10,000
0 is more preferable. The molecular weight of the thermoplastic resin can be determined by a viscosity method or a vapor osmotic pressure method.

From the viewpoint of ease of production, the melting point (or softening point) of the thermoplastic resin is preferably 80 ° C. or higher, and 120 ° C.
The above is more preferable. There is no particular upper limit, but a surfactant,
20 from the viewpoint of thermal decomposability of hydrophilic compounds and thermoplastic resins
The temperature is preferably 0 ° C or lower, more preferably 150 ° C or lower. The melting point (or softening point) of the thermoplastic resin is JIS K006.
4: 1992.

The thermoplastic resin used in the present invention is preferably one or more selected from polyolefin, polyamide, polyester or polyacetal.

As the polyolefin, polyethylene,
Examples thereof include olefin homopolymers such as polypropylene, poly-1-butene, polymethylpentene, polymethylbutene, and polybutadiene, olefin copolymers such as propylene / ethylene random copolymer, and the like. Polyethylene, polypropylene, poly- 1-butene is particularly preferred. Further, it may have a fluorine atom, and examples thereof include polytetrafluoroethylene (PTFE).

Examples of polyamides include aliphatic polyamides such as nylon-6, nylon-66, nylon-10, nylon-12 and nylon-46, and aromatic polyamides produced from aromatic dicarboxylic acids and aliphatic diamines. Nylon-6 is particularly preferred.

Examples of the polyester include aromatic polyesters such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate, polycaprolactone and polyhydroxybutyrate, and polyethylene terephthalate is particularly preferable.

Examples of the polyacetal include polyformaldehyde (polyoxymethylene), polyacetaldehyde, polypropionaldehyde and polybutyraldehyde, and polyformaldehyde is particularly preferable.

The above thermoplastic resins may be used alone or in combination of two or more kinds. Among these resins, polyolefins, especially polyethylene,
Polypropylene is preferred. In addition, polyolefin is
It is preferably linear rather than branched.

The hydrophilic compound used in the present invention is incompatible with the thermoplastic resin in the mixed state, and it is preferable that the hydrophilic compound has a larger surface tension than the thermoplastic resin.

The hydrophilic compound preferably has a solubility parameter δ [(MPa) ^1/2 ] of 20 or more. Specifically, at least one selected from the group consisting of water (47.9), polyhydric alcohol and lower alcohol is preferable. Polyhydric alcohols such as ethylene glycol (29.9), diethylene glycol (24.8), triethylene glycol (21.9), tetraethylene glycol (20.3), polyethylene glycol, propylene glycol (25.8) and other dihydric alcohols,
Trihydric alcohols such as glycerin (33.8), diglycerin, triglycerin, polyglycerin, and trimethylolpropane, hexitols such as sorbitol, aldoses such as glucose, compounds having a sugar skeleton such as sucrose, and others such as pentaerythritol. . As lower alcohol, isopropanol (23.5), butyl alcohol (2
3.3) and the like. These may be used alone or in combination. In the parentheses, the δ value of the solubility parameter is shown.

The molecular weight of the hydrophilic compound is preferably 3000 or less, more preferably 1000 or less, and particularly preferably 500 or less. The lower limit is preferably 30 or more, more preferably 50 or more. The boiling point or decomposition temperature of the hydrophilic compound is the melting point (or softening point) of the thermoplastic resin used.
Must be higher than.

Therefore, among these, polyhydric alcohols are preferable, and glycerin, diethylene glycol and triethylene glycol are more preferable.

In the production method of the present invention, a surfactant is used to form an emulsion when both the thermoplastic resin and the hydrophilic compound are mixed at a temperature equal to or higher than the melting point (or softening point).

In the present invention, as the surfactant, an anionic surfactant, a nonionic surfactant, a cationic surfactant,
Amphoteric surfactants and the like can be widely used.

The surfactant needs to take into consideration the dispersibility of the thermoplastic resin and the hydrophilic compound, and the thermal denaturation and decomposition during melt mixing.

Specifically, examples of the anionic surfactant include those shown below. (1) Alkylbenzenesulfonate, preferably a linear or branched alkylbenzenesulfonate having an alkyl group having an average carbon number of 10 to 16. (2) Alkyl ether sulfate or alkenyl ether sulfate, preferably having a linear or branched alkyl or alkenyl group having an average carbon number of 10 to 20 and having an average of 0.5 to 8 mol of ethylene in one molecule. Oxide, propylene oxide, butylene oxide, ethylene oxide and propylene oxide 0.1 / 9.9 to 9.9 /
Alkyl ether sulfates or alkenyl ether sulfates in which ethylene oxide and butylene oxide are added at a ratio of 0.1 or 0.1 / 9.9 to 9.9 / 0.1. (3) Alkyl sulphate or alkenyl sulphate, preferably an alkyl sulphate or alkenyl sulphate having an alkyl or alkenyl group with an average carbon number of 10-20. (4) Olefin sulfonate, preferably 10 to 10 on average
Olefin sulfonate having 20 carbon atoms in one molecule. (5) Alkane sulfonate, preferably 10-2 on average
An alkane sulfonate having 0 carbon atoms in one molecule. (6) Higher fatty acid salt, preferably saturated or unsaturated fatty acid salt having an average of 10 to 24 carbon atoms in one molecule. (7) (Amido) ethercarboxylic acid type surfactant. (8) α-Sulfo fatty acid salt or ester, preferably α-sulfo fatty acid salt or ester having an alkyl group or an alkenyl group having an average of 10 to 20 carbon atoms. (9) N-acyl amino acid type surfactants, preferably N-acyl amino acid type surfactants having an acyl group having 8 to 24 carbon atoms and a free carboxylic acid residue (for example, N-acyl sarcosinate, N-acyl -Β-alanine etc.). (10) A phosphoric acid ester type surfactant, preferably a phosphoric acid mono- or diester type surfactant having an alkyl group or an alkenyl group having 8 to 24 carbon atoms or an alkylene oxide adduct thereof. (11) Sulfosuccinate type surfactants, preferably sulfosuccinates such as higher alcohols having 8 to 22 carbon atoms or ethoxylates thereof, or higher fatty acid amide-derived sulfosuccinates, (12) polyoxyalkylene fatty acid amide ether sulfuric acid salt. (13) Monoglyceride sulfate, preferably monoglyceride sulfate having a linear or branched, saturated or unsaturated fatty acid group having 8 to 24 carbon atoms. (14) Acylated isethionate, preferably 8 carbon atoms
An acylated isethionate having from 24 to 24 straight or branched chain saturated or unsaturated fatty acid groups. (15) Alkyl glyceryl ether sulphate or alkyl glyceryl ether sulphonate, preferably alkyl glyceryl ether sulphate having a linear or branched alkyl group or alkenyl group having 8 to 24 carbon atoms or an alkylene oxide adduct thereof. Salts or alkyl glyceryl ether sulfonates. (16) alkyl or alkenyl amide sulfonate,
An alkyl or alkenyl amide sulfonate preferably having a linear or branched alkyl group or alkenyl group having 8 to 24 carbon atoms. (17) Alkanolamide sulfosuccinate, preferably an alkanolamide sulfosuccinate having a linear or branched alkyl group or alkenyl group having 8 to 24 carbon atoms. (18) Alkylsulfoacetate, preferably an alkylsulfoacetate having a linear or branched alkyl group or alkenyl group having 8 to 24 carbon atoms. (19) Acylated taurate, preferably having 8 to 2 carbon atoms
An acylated taurate having a linear or branched saturated or unsaturated fatty acid group of 4. (20) N-acyl-N-carboxyethylglycine salt, preferably N- having an acyl group having 6 to 24 carbon atoms
Acyl-N-carboxyethylglycine salt.

Examples of salts of these anionic surfactants include alkali metal salts such as sodium and potassium, alkaline earth metal salts such as calcium and magnesium, ammonium salts, and alkanol groups having 2 or 3 carbon atoms in an amount of 1 to 3. Specific examples thereof include alkanolamine salts (for example, salts of monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine, etc.).

As the nonionic surfactant, for example, a polyoxyalkylene alkyl ether having a linear or branched alkyl group or alkenyl group having an average carbon number of 10 to 24 and added with ethylene oxide, propylene oxide or butylene oxide. Or polyoxyalkylene alkenyl ether; fatty acid monoglycerin ester having 8 to 22 carbon atoms; fatty acid glycol ester having 8 to 20 carbon atoms; ethoxylate of monoglyceride having 8 to 20 carbon atoms; higher fatty acid sucrose ester having 8 to 20 carbon atoms ;
Higher fatty acid sorbitan ester having 8 to 20 carbon atoms; polyglycerin fatty acid ester having an acyl group having 8 to 20 carbon atoms; higher fatty acid monoethanolamide or diethanolamide having 8 to 20 carbon atoms or ethoxylates thereof; polyoxyethylene curing Castor oil; carbon number 8-20
Polyoxyalkylene sorbitan fatty acid ester having an acyl group; Polyoxyethylene sorbit fatty acid ester having an acyl group having 8 to 20 carbon atoms;
Alkyl saccharide-based surfactant having 18 linear or branched alkyl group, alkenyl group or alkylphenyl group; alkylamine oxide or alkyl having 8 to 20 linear or branched alkyl group or alkenyl group Amidoamine oxide; ether compound or ester compound of polyhydric alcohol having a linear or branched alkyl or alkenyl group having 8 to 20 carbon atoms;
Siloxane derivatives (JP-A-4-108795), silicone-based surfactants such as polyoxy-modified silicone; polyoxyalkylene ethers, polyoxyalkylene alkylaryl ethers, polyoxyalkylene lanolin alcohols, polyoxyalkylene glyceryl monofatty acid esters, polyoxy Examples thereof include alkylene fatty acid ester, higher fatty acid glycerin ester, pluronic type block polymer nonionic activator, tetronic type block polymer nonionic activator, polyoxyalkylene fatty acid amide, polyoxyalkylene alkylamide, and polyethyleneimine derivative.

The cationic surfactant is not particularly limited as long as it is used in ordinary cosmetics, and examples thereof include quaternary ammonium salts. Further, the amphoteric surfactant is not particularly limited as long as it is used in ordinary cosmetics, for example, amide amino acid type, carbobetaine type, amidobetaine type, sulfobetaine type, amidosulfobetaine type, imidazole. Examples thereof include nium betaine type, amino acid type, phosphobetaine type, and phosphate ester type. One or more of these surfactants can be mixed and used.

Among these, nonionic surfactants are preferable, for example, they have a linear or branched alkyl group or alkenyl group having an average carbon number of 10 to 24, and ethylene oxide, propylene oxide or butylene oxide is added thereto. Polyoxyalkylene alkyl ether or polyoxyalkylene alkenyl ether, having 8 to 22 carbon atoms
The fatty acid monoglycerin ester of is more preferable.

In the present invention, other solid or liquid components such as coloring materials such as organic dyes, silicone compounds and antioxidants may be melted or present in the emulsion.

Next, the emulsion obtained as described above is applied to a rotating disk atomizer, a single fluid, or a multi-fluid nozzle of two or more fluids, preferably 5 to 5
The particles solidified by cooling are recovered by spraying in a gas phase at 0 ° C.
Preferably, a multi-fluid nozzle with two or more fluids is used and sprayed into the gas phase with a compressed gas. As the compressed gas used as the fluid, compressed air or compressed nitrogen of preferably 9.8 × 10 ⁴ Pa or more, and more preferably 9.8 × 10 ^{4 to} 29.4 × 10 ⁴ Pa can be used. It is preferable to use, as the gas, one heated to the spray temperature because it can prevent clogging due to cooling at the nozzle portion and continuously produce particles.

The spraying temperature is preferably 600 mPa · s or less, more preferably 300 mPa · s or less, particularly preferably 100 mPas, from the viewpoint of improving sprayability, of the mixture of the thermoplastic resin and the hydrophilic compound.・
The temperature may be s or less. There is no lower limit, but 5
It is preferably mPa · s or more.

The obtained particles may be washed. In this operation, it is preferable to remove the hydrophilic compound and the surfactant with a solvent at a temperature lower than the melting point (or softening point) of the thermoplastic resin. The hydrophilic compound and the surfactant may be removed by reducing the pressure. Preferably, 1 to 100 parts by mass of a solvent is added to 1 part by mass of the obtained particles and mixed at the above temperature to elute the hydrophilic compound and the surfactant. By repeating such washing, particles having concave portions on the surface can be obtained.

The solvent is not particularly limited as long as it dissolves the hydrophilic compound and the surfactant and does not dissolve the thermoplastic resin. For example, water; lower alcohols such as ethanol and isopropanol; lower ketone compounds; aliphatic hydrocarbons such as hexane, heptane, dodecane, cyclohexane, methylcyclohexane, isooctane, hydrogenated triisobutylene, fragrances such as benzene, toluene, xylene and ethylbenzene. Hydrocarbon-based solvents such as group hydrocarbons; silicone-based solvents such as octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane.

[Cosmetic] The content of the amphiphilic particles according to the present invention in the cosmetic of the present invention can be appropriately selected according to the purpose of the cosmetic, and is not particularly limited. , 0.1 to 50 mass% is preferable, and 1 to 30 mass%
Is more preferable.

The form of the cosmetic of the present invention is not particularly limited,
Any of water-in-oil type or oil-in-water type emulsion cosmetics, oily cosmetics, spray cosmetics, stick cosmetics, water-based cosmetics, sheet cosmetics, gel cosmetics and the like may be used. The type of cosmetics of the present invention is not particularly limited, and examples thereof include packs, foundations, lipsticks, lotions, cold creams, hand creams, skin cleansers, softening cosmetics, nutritional cosmetics, astringent cosmetics, whitening cosmetics, Skin cosmetics such as wrinkle-improving cosmetics, anti-aging cosmetics, cleaning cosmetics, antiperspirants, deodorants and the like; hair cosmetics such as shampoos, rinses, treatments, hair styling agents and hair nourishing agents.

The cosmetic of the present invention preferably contains alcohol. Examples of the alcohol include monohydric or polyhydric alcohols having 1 to 6 carbon atoms such as ethanol, glycerin, 1,3-butylene glycol, propylene glycol, and sorbitol, and among them, monohydric alcohol, particularly ethanol is preferable. The blending amount of alcohol is preferably 5 to 30% by mass in the cosmetic of the present invention, and particularly preferably 2 to 50 times by mass that of the amphiphilic particles according to the present invention.

In the cosmetic of the present invention, other components generally used as cosmetic ingredients are appropriately blended depending on the form, type and the like of the above-mentioned cosmetics within a range not impairing the effects of the present invention. be able to.

Examples of such cosmetic ingredients include extenders such as mica, talc, sericite, kaolin, nylon powder, polymethylsilsesquioxane, and barium sulfate; solid pigments such as titanium oxide, zinc oxide, and iron oxide;
These powders are surface-hydrophobicized by silicone treatment, metal soap treatment, N-acylglutamic acid treatment, etc .; solid or liquid paraffin, microcrystalline wax, petrolatum, ceresin, ozokerite, montan wax, and other hydrocarbons. ; Olives, earth wax, carnauba wax,
Vegetable oils such as lanolin and whale wax, animal oils or waxes; stearic acid, palmitic acid, oleic acid, glycerin monostearate ester, glycerin distearate ester, glycerin monooleate ester, isopropyl myristate ester, isopropyl stearic acid ester Fatty acids such as esters and butyl stearates, or esters thereof; higher alcohols such as cetyl alcohol, stearyl alcohol, palmityl alcohol, hexyldecyl alcohol; adsorption or enhancement of cationized cellulose, carboxybetaine-type polymers, cationized silicone, etc. Viscous agents; polyhydric alcohols such as glycol and sorbitol, which have moisturizing action; whitening agents, analgesic and anti-inflammatory agents, antipruritic agents, bactericidal and disinfectant agents, astringent agents, emollients, hormonal agents, etc. Water; surfactant; W / O or O /
W type emulsifiers; emulsifiers for silicone oils such as polyether modified silicones, polyether / alkyl modified silicones, glyceryl ether modified silicones; thickeners such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, polyacrylic acid, tragacanth, agar, gelatin; In addition, an emulsion stabilizer, a chelating agent, an ultraviolet protective agent, a pH adjusting agent, a preservative, a pigment, a fragrance and the like can be mentioned.

[0047]

Example 1 Polyethylene wax (Mitsui High Wax HW-200P, manufactured by Mitsui Chemicals, Inc., molecular weight 2000, melting point 122 ° C.) as a thermoplastic resin, diethylene glycol (melting point −6.5 ° C.) as a hydrophilic compound, As a surfactant, polyoxyethylene lauryl ether (Emulgen 10
No. 5, manufactured by Kao Co., Ltd. was melt-mixed at a mass mixing ratio of 100: 20: 1, sufficiently dispersed and mixed by a homomixer, and heated and dissolved at 180 ° C. Next, it was spray-cooled in a gas phase of 25 ° C. with a nitrogen stream of 180 ° C. by a two-fluid nozzle (glass sprayer M type, manufactured by SANSYO), and collected as solid particles. The average particle size of the obtained particles was 15 μm. The number average diameter of the recesses was about 1/10 of the particle diameter. An electron micrograph of the obtained particles is shown in FIG.

Comparative Example 1 The same procedure as in Example 1 was carried out except that diethylene glycol and Emulgen 105 were removed, and the solid particles were collected. The average particle size of the obtained particles was 15 μm.

The particles obtained in Example 1 and Comparative Example 1 were evaluated for water dispersibility and hexane dispersibility by the following methods, and the surface shape of the particles was observed. The results are shown in Table 1.

<Water dispersibility / hexane dispersibility> 5 g of particles were dispersed in 100 g of water or 100 g of hexane, and the state after 1 minute of mixing was evaluated according to the following criteria. ◯: Particles are almost uniformly dispersed in the liquid. X: Particles float on the upper layer and are separated.

Comparative Example 2 Polyoxyethylene lauryl ether (Emulgen 123P, manufactured by Kao Corporation) was added to 5 parts by mass of the particles of Comparative Example 1.
0.042 mass part was added and the water dispersibility and hexane dispersibility were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0052]

[Table 1]

Formulation Example 1 A lotion having the following composition was prepared and applied to the skin on the inner side of the forearm, and the feel immediately after and after 4 hours (after drying) was evaluated by a professional panelist (1 person). The results are shown in Table 2.

<Lotion composition> 50 g of urea Deionized water 200g Glycerin 5g Particles of Example 1 5 g

Comparative Formulation Example 1 A lotion was prepared in the same manner as in Formulation Example 1 except that the particles of Comparative Example 1 were used in place of the particles of Example 1, and the feel was evaluated in the same manner. The results are shown in Table 2.

Comparative Prescription Example 2 A lotion was prepared in the same manner as in Prescription Example 1 except that the particles of Comparative Example 1 were used in place of the particles of Example 1 and 0.042 g of Emulgen 123P was further added, and the same touch feeling was obtained. evaluated.
The results are shown in Table 2.

[0057]

[Table 2]

As shown in Tables 1 and 2 above, the spherical particles of the present invention are excellent in water dispersibility, touch and durability of touch. On the other hand, in Comparative Formulation Example 2, since the surface of the particles is made hydrophilic by the surfactant, it is likely that the surface of the particles is easily removed from the applied portion on the skin, and the durability of the feel is affected.

[0059]

INDUSTRIAL APPLICABILITY The amphipathic particles of the present invention can be manufactured at low cost, can be dispersed in water without a surfactant, and can impart a dry feel on the skin for a long time.

[Brief description of drawings]

1 is an electron micrograph of particles obtained in Example 1. FIG.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // C08L 101: 00 C08L 101: 00 F term (reference) 4C083 AC122 AC682 AD022 AD042 BB25 BB26 CC01 CC04 DD23 DD27 EE06 EE07 FF01 4F070 AA12 AA13 AA15 AA42 AA47 AA54 AC36 AC40 AC50 AE14 AE30 DA34 DC11

Claims (5)

[Claims] 1. An amphipathic particle having a concave portion on the surface of the particle. 2. The inside of the recess is hydrophilic and the particle surface is
The amphipathic particle according to claim 1, which is hydrophobic. 3. The number average diameter of the recesses is 1/10 of the particle diameter.
The amphipathic particle according to claim 1 or 2, which is from 00 to 1/2. 4. A cosmetic containing the amphipathic particles according to claim 1. 5. A method for producing amphipathic particles, which comprises spraying a mixture of a thermoplastic resin, a hydrophilic compound and a surfactant into a gas phase at a temperature equal to or higher than the melting point (or softening point) of the thermoplastic resin.