JP2005145860A - External preparation composition for skin coloration - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an external preparation composition for skin coloration comprising a new thickener exhibiting excellent thickening effect and dyeing effect, especially a composition that exhibits excellent thickening effect even in an external preparation composition for skin coloration highly formulated with ethanol and is preferable as a self-tanning cosmetic base. <P>SOLUTION: In the composition comprising an organic solvent or an oil component as a dispersion medium and water as a dispersed phase, the external preparation composition for skin discoloration comprises a thickener composed of a microgel obtained by dissolving a water-soluble ethylenic unsaturated monomer in the dispersed phase and radically polymerizable the monomer in the dispersed phase, and dihydroxyacetone. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an external preparation composition for skin coloring, which contains a thickener comprising a microgel. More specifically, the present invention relates to an external preparation composition for skin coloring that exhibits an excellent thickening effect and an excellent dyeing effect. In particular, the present invention relates to an external preparation composition for skin coloring that exhibits an excellent thickening effect even when ethanol is highly blended.

An external preparation for skin such as cosmetics is blended with a thickener since it needs an appropriate viscosity because it needs to be applied to the skin.
Examples of water-soluble thickeners include various polysaccharides, natural polymers such as gelatin, synthetic polymers such as polyoxyethylene and crosslinked poly (meth) acrylic acid, and inorganic minerals such as montmorillonite and silica. .

  On the other hand, the most widely used thickener for cosmetics is a polymer of acrylic acid collectively called carboxyvinyl polymer, and the product names are Hibiswako (Wako Pure Chemicals), Shintalen (3V SIGMA), It is commercially available as Carbopol (Goodrich). These thickeners are chemically cross-linked polymers (The B.F. Goodrich Company, Specialty Polymers and Chemical Div., Carbopol Data Sheets and Applications Literature). Since it is inexpensive, has a high thickening effect, and gels in a small amount, it is frequently used as a water-soluble thickener or stabilizer in the pharmaceutical and cosmetic industries, particularly in cosmetics. Such an aqueous dispersion of a crosslinked polymer has a very high thickening effect and is widely used as a thickener for cosmetics or daily necessities (see Non-Patent Document 1). Hydroxypropyl cellulose is also frequently used as a nonionic thickener.

  However, the carboxyvinyl polymer has a problem that the pH range in which the viscosity can be increased is limited. In the carboxyvinyl polymer, the polymer swells and thickens in water when the carboxyl group contained in the polymer is in a dissociated state. Therefore, the carboxyvinyl polymer does not function as a thickener in a pH range of weak acidity or lower where the carboxyl group is not sufficiently dissociated, and instead of this, the development of a thickener capable of thickening over a wide pH range has been developed. The current situation is strongly desired.

  Furthermore, some cosmetic formulations have high ethanol concentrations, but at present, it is extremely difficult to efficiently thicken such formulations with conventional thickeners such as carboxyvinyl polymer and hydroxypropylcellulose. It is a problem. Carboxyvinyl polymer is inhibited from dissociation of carboxyl groups under acidic conditions of pH 5 or lower or in an aqueous solution containing salt, and the viscosity is extremely lowered to prevent gelation. For this reason, it cannot be used in a formulation that requires acidic conditions and a salt coexistence system. In addition, the adjustment of pH is important for an external preparation composition for skin in which drug stability is an important point. For example, at pH 5 or higher, a drug having an ester bond such as nicotinic acid benzyl ester as a blood circulation promoter is unstable. On the other hand, it is difficult to increase the viscosity in the stable pH range. Further, in the presence of salts, it is necessary to greatly increase the blending amount in order to maintain the thickening effect, and as a result, the usability is significantly impaired. That is, when applied to the skin, a sticky feeling is produced, and this sticky feeling becomes a very serious problem in terms of usability of the external preparation for skin.

  In order to solve this problem, a copolymer of acrylamide alkyl sulfonic acid and (meth) acrylic acid (Patent Document 1), a copolymer of acrylamide alkyl sulfonic acid and an alkyl group-containing unsaturated monomer (Patent Document) 2) Or a homopolymer of 2-acrylamido-2-methylpropanesulfonic acid (Patent Document 3) is applied to cosmetics.

  However, although the polymer having an acrylamide alkyl sulfonic acid in the skeleton has improved acid resistance and can be used in a formulation requiring acidic conditions, a sticky feeling at the time of drying, which is considered to be derived from acrylic acid, occurs, and the thickened cosmetic. It can not be said that the usability is sufficiently satisfactory.

  In view of the above circumstances, Kaneda et al. Added a copolymer obtained by copolymerizing 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof, dialkylacrylamide and a crosslinkable monomer to a cosmetic. It has been found that satisfactory usability can be exhibited when blended as a sticking agent (Patent Document 4). This copolymer is a polymer gel (polymer gel) obtained by radical polymerization in a homogeneous polymerization system, and after the polymer gel has been manufactured, it is mechanically crushed to produce a composition for external application to the skin as a thickener powder. It is a technology for blending into products. In some cases, the polymer gel particles are large, causing problems in the appearance of the cosmetic. Furthermore, there was room for further improvement in the thickening effect.

The thickener used in the present invention is a polymer microgel produced by a polymerization method generally referred to as a reverse phase emulsion polymerization method, and is disclosed in Patent Document 4. The polymerization method and mechanical properties are different from those of a thickener made of a synthetic polymer obtained by a homogeneous polymerization system.
A microgel is a fine particle of a synthetic polymer electrolyte produced by a reverse phase microemulsion polymerization method. The thickener comprising the microgel of the present invention swells in water, ethanol or a water-ethanol mixed solution, and can provide a high-viscosity solution that is visually uniform in appearance.
The method for producing the thickener in the present invention, that is, the polymerization system of the microgel used as the thickener is different from the homogeneous polymerization system for producing the synthetic polymer which is a conventional thickener.
The synthetic polymer based on the homogeneous polymerization system disclosed in Patent Document 4 is not a microgel used in the present invention, but must be pulverized into a powder state in order to be blended into a cosmetic after polymerization of the synthetic polymer. In addition, a synthetic polymer gel is noticeable and may cause problems in appearance.
On the other hand, the microgel used in the present invention is polymerized in a heterogeneous polymerization system. The resulting synthetic polymer becomes a fine polymer gel, that is, a microgel, and when blended into cosmetics, it does not need to be pulverized and powdered, exhibits an excellent thickening effect and excellent usability. Furthermore, the appearance of the cosmetic is also preferable.

As for the reverse phase emulsion polymerization method of a polymer, Patent Document 5 describes a technique of producing a water-swellable polymer using acrylic acid by reverse phase polymerization and applying it as a thickener. However, this is different from the microgel used in the present invention, which improves the shortcomings of the currently widely used carboxyvinyl polymers.
Patent Document 6 discloses that microgel particles of a water-absorbing resin are produced in a certain size or more so as to be suitable for diapers or sanitary products, but this can be applied to a cosmetic thickener. It is not a technique and is completely different from the microgel used in the present invention.

  On the other hand, self-tanning bases formulated with dihydroxyacetone (DHA) are prone to discoloration and odor change due to the reactivity of dihydroxyacetone, and there are few thickeners that achieve both thickening and dyeing effects. It was.

For example, Patent Document 7 and Patent Document 8 describe an external preparation composition for skin coloration containing DHA using a thickener (trade name Sepigel 305) comprising a cross-linked copolymer of acrylamide and 2-acrylamido-2-methylpropanesulfonic acid. Things are listed.
Patent Document 9 discloses an external preparation composition for skin coloration containing DHA using a thickening agent (trade name Salcare) comprising a cationic polymer composed of dialkylaminoalkyliacrylate or dialkylaminoalkylimethacrylate and acrylamide. Things are listed.
Although these thickeners have relatively good thickening and dyeing effects, they are not always sufficient. In addition, the base may change color. Furthermore, there is a problem that it is difficult to produce a transparent base. Furthermore, when alcohol is blended in a high amount, a problem arises in stability.

JP-A-9-157130 JP-A-10-279636 JP-A-10-67640 JP-A-2001-114641 Japanese Patent No. 1911623 Japanese Patent Laid-Open No. 9-12613 JP-A-6-56630 JP-A-6-199644 JP-T-8-508995 Barry, BW and Meyer MC Int. J. Pharm 2: 1 (1979)

  As a result of intensive studies in view of the above-mentioned circumstances, the present inventors have surprisingly found that a microgel comprising a synthetic polymer electrolyte produced by a specific reverse-phase emulsion polymerization is used as a skin coloring external preparation composition containing dihydroxyacetone. It has been found that a stable composition exhibiting an extremely excellent thickening effect and dyeing effect can be provided when it is added to the present invention, and the present invention has been completed.

  This thickening agent comprising a microgel exhibits an excellent thickening effect, especially in an external preparation composition for skin coloring that contains a high amount of ethanol, and has a high viscosity and excellent stability. It has been found that a base and an emulsifying base can be provided. Furthermore, when diisopropyl sebacate was mix | blended with the external preparation composition for skin coloring of this invention, it discovered that the dyeability of DHA improved further.

  The present invention is used for the use of a thickener for blending a microgel comprising a synthetic polymer electrolyte produced by a specific reverse phase emulsion polymerization (reverse phase microemulsion polymerization) into a skin coloring external preparation composition, Providing external gel composition for skin coloring that contains a polymer gel consisting of a synthetic polyelectrolyte produced by homogeneous polymerization or reversed-phase suspension polymerization, and a new type of thickener that solves the disadvantages of carboxyvinyl polymer. can do.

  That is, the present invention relates to a composition comprising an organic solvent or an oil as a dispersion medium and water as a dispersed phase, from a microgel obtained by dissolving a water-soluble ethylenically unsaturated monomer in the dispersed phase and radical polymerization in the dispersed phase. An external preparation composition for skin coloring containing a thickener and dihydroxyacetone.

  In the present invention, the content of the dihydroxyacetone is 0.1 to 7.5% by mass, and the thickener composed of the microgel is 0.01 to 10% by mass with respect to the total amount of the composition. The above-described external preparation composition for coloring the skin is provided.

  Furthermore, this invention provides said external preparation composition for skin coloring characterized by containing 1-70 mass% of ethyl alcohol further.

  Moreover, this invention provides said external preparation composition for skin coloring characterized by content of the said ethyl alcohol being 5.0-30 mass% or more with respect to the composition whole quantity.

  The present invention further provides the external preparation composition for skin coloring according to any one of the above, which further contains diisopropyl sebacate.

  Furthermore, the present invention further provides the above-mentioned external preparation composition for skin coloring, characterized by containing an ultraviolet absorber.

  Moreover, this invention provides the said external preparation composition for skin coloring characterized by the viscosity of the said composition in 30 degreeC being 10-100,000 mPa * s.

  Furthermore, the present invention provides the above-mentioned external preparation composition for skin coloring, wherein the composition is a transparent gel composition.

  The present invention also provides the above-mentioned external preparation composition for skin coloring, wherein the composition is an emulsified gel composition emulsified with a surfactant.

  Furthermore, the present invention provides the above-mentioned external preparation composition for skin coloring, wherein the composition is a self-tanning cosmetic.

  Moreover, this invention provides said external preparation composition for skin coloring containing a coloring agent further.

ADVANTAGE OF THE INVENTION By this invention, the external preparation composition for skin coloring excellent in the thickening effect and the dyeing effect can be provided.
In particular, the thickener used in the present invention is a composition that exhibits an excellent thickening effect and is excellent in stability even in an external preparation composition for coloring the skin that is highly blended with ethanol.
The thickener comprising the microgel exhibits an excellent thickening effect even in an external preparation composition for skin coloring that contains ethanol in a high amount. Moreover, it has a high viscosity (about 10,000 Pa · s at 0.2%) and can thicken even under acidic conditions (a stable thickening is possible up to pH 6 to 3). And the emulsion base by the transparent gel base and nonionic surfactant excellent in stability can be provided. The reactivity between the thickener and DNA is low, and discoloration and odor are unlikely to occur. Further, when diisopropyl sebacate is blended, the dyeability of DHA is further improved.
The composition of the present invention also exhibits a refreshing, refreshing, light, and non-sticky effect even when used.

  Hereinafter, the present invention will be described in detail.

  The thickener composed of a microgel used in the present invention is a composition having an organic solvent or oil as a dispersion medium and water as a dispersed phase, in which a water-soluble ethylenically unsaturated monomer is dissolved in the dispersed phase and radicals are formed in the dispersed phase. It is a thickener composed of a synthetic polymer microgel obtained by polymerization.

That is, a polymer microgel produced by a polymerization method generally referred to as a reverse emulsion polymerization method is used for a thickener, and is disclosed in Patent Document 4 (Japanese Patent Laid-Open No. 2001-114641). The polymerization method and mechanical properties are different from those of a thickener made of a synthetic polymer obtained by a homogeneous polymerization system.
A microgel is a fine particle of a synthetic polymer electrolyte produced by a reverse phase microemulsion polymerization method. The thickener comprising the microgel of the present invention swells in water, ethanol or a water-ethanol mixed solution, and can provide a high-viscosity solution that is visually uniform in appearance.

The method for producing the thickener used in the present invention, that is, the polymerization system of the microgel used as the thickener is different from the homogeneous polymerization system for producing the synthetic polymer which is a conventional thickener.
The synthetic polymer based on the homogeneous polymerization system disclosed in Patent Document 4 is not a microgel used in the present invention, but must be pulverized into a powder state in order to be blended into a cosmetic after polymerization of the synthetic polymer. In addition, a synthetic polymer gel is noticeable and may cause problems in appearance.
On the other hand, the microgel used in the present invention is polymerized in a heterogeneous polymerization system. The resulting synthetic polymer becomes a fine polymer gel, that is, a microgel, and when blended into cosmetics, it does not need to be pulverized and powdered, exhibits an excellent thickening effect and excellent usability. Furthermore, the appearance of the cosmetic is also preferable.

As for the reverse phase emulsion polymerization method of polymer, a water-swellable polymer using acrylic acid is produced by reverse phase polymerization in Patent Document 5 (Patent No. 1911623) and applied as a thickener. Although there is a description of the technology, this is different from the microgel used in the present invention which improves the shortcomings of carboxyvinyl polymers which are currently widely used.
Further, Patent Document 6 (Japanese Patent Laid-Open No. 9-12613) discloses that microgel particles of a water-absorbing resin are produced in a certain size or more so as to be suitable for diapers or sanitary products. Is not a technology that can be applied to a cosmetic thickener and is completely different from the microgel used in the present invention.

The thickener used in the present invention is produced by a reverse phase emulsion polymerization method. That is, in a composition having an organic solvent or an oil as a dispersion medium and water as a dispersed phase, it is produced by dissolving a water-soluble ethylenically unsaturated monomer in the dispersed phase and radical polymerization in the dispersed phase. The polymerized microgel is washed and dried, but need not be crushed.
In particular, by using a surfactant adjusted to an appropriately selected hydrophilic / hydrophobic balance (HLB), the microgel under the condition that the polymerization system in the inverse emulsion polymerization forms a one-phase microemulsion or a fine W / O emulsion. It is preferred that a thickener consisting of

  A single-phase microemulsion is a state in which the oil phase and the water phase coexist thermodynamically and the interfacial tension between the oil and water is minimized. The fine W / O emulsion is thermodynamically unstable, but oil and water are present as fine W / O emulsions stably in kinetics. Generally, the particle diameter of the inner aqueous phase of the fine W / O emulsion is about several tens to 100 nm. These states are determined only by the composition and temperature of the system and do not depend on mechanical stirring conditions.

The composition constituting the polymerization system is composed of an organic solvent or oil that does not mix with water (dispersing medium constituting the outer phase) and a dispersed phase consisting of water (constituting the inner phase).
Preferable organic solvents include alkanes such as pentane, hexane, heptane, octane, nonane, decane, undecane; cycloalkanes such as cyclopentane, cyclohexane, cycloheptane, cyclooctane; benzene, toluene, xylene, decalin, naphthalene, etc. And aromatic and cyclic hydrocarbons.
Preferred oils include nonpolar oils such as paraffin oil.
The water-soluble ethylenically unsaturated monomer is dissolved in water as a dispersed phase, then mixed with an organic solvent or oil as a dispersion medium, heated to a desired temperature, and then a polymerization initiator is added to the aqueous phase for polymerization. .

  In general, in the heterogeneous polymerization method, it is known that the properties of the polymer produced vary depending on the stirring conditions during the polymerization. The reason is that since the emulsification system is not thermodynamically stable, the shape and size of the emulsified particles change depending on the stirring conditions. In the present invention, it has been found that these problems can be avoided by performing polymerization in a thermodynamically stable one-phase microemulsion region or a fine W / O emulsion region that exists in the vicinity of a metastable one-phase region. It was. Specifically, the composition of the polymerization system (type of organic solvent, so that the above-mentioned one-phase microemulsion or fine W / O emulsion region appears in the vicinity of the optimum polymerization temperature of the polymerization initiator for normal thermal polymerization or redox polymerization. By adjusting the surfactant (HLB), it became possible to obtain a microgel with a high thickening effect by polymerizing the polymer in a fine aqueous phase (water droplets).

A phase diagram example is shown in FIG. FIG. 1 is a three-component phase diagram of hexane (indicated by W) / surfactant / water-soluble ethylene monomer aqueous solution (indicated by O) when hexane is used as the organic solvent. The region A shown in the figure is a one-phase microemulsion region to a fine W / O emulsion region, and by performing polymerization in this region, preferable microgel polymerization is possible.
In contrast, conventional polymer thickeners based on suspension polymerization (for example, the method described in Patent Document 4) have difficulty in controlling the particle size of water droplets during polymerization, and it is difficult to obtain good-quality microgels. is there.

（Ｒ₁はＨまたはメチル基、Ｒ₂及びＲ₃はそれぞれ独立にメチル基、エチル基、プロピル基、イソプロピル基を表わす。） The water-soluble ethylenically unsaturated monomer is preferably a combination of a nonionic monomer and an ionic monomer (anionic monomer or cationic monomer).
The nonionic monomer is preferably a dialkylacrylamide represented by the general formula (1).
General formula (1)

(R ₁ represents H or a methyl group, and R ₂ and R ₃ each independently represents a methyl group, an ethyl group, a propyl group, or an isopropyl group.)

（Ｒ₄及びＲ₅はそれぞれ独立にＨ又はメチル基、Ｒ₆は炭素原子数１〜６の直鎖若しくは分岐のアルキル基、Ｘは金属イオン若しくはＮＨ₃を表わす。）
一般式（３）

（Ｒ₇はＨ又はメチル基、Ｒ₈はＨまたは炭素原子数１〜６の直鎖若しくは分岐のアルキル基、Ｒ₉は炭素原子数１〜６の直鎖若しくは分岐のアルキル基、Ｒ₁₀、Ｒ₁₁、Ｒ₁₂はメチル基またはエチル基、Ｙは金属イオンを表わす。） The ionic monomer is preferably an anionic acrylamide derivative represented by the general formula (2) or a cationic acrylamide derivative represented by the general formula (3).












General formula (2)

(R ₄ and R ₅ each independently represent H or a methyl group, R ₆ represents a linear or branched alkyl group having 1 to 6 carbon atoms, and X represents a metal ion or NH _3. )
General formula (3)

(R ₇ is H or a methyl group, R ₈ is H or a linear or branched alkyl group having 1 to 6 carbon atoms, R ₉ is a linear or branched alkyl group having 1 to 6 carbon atoms, R ₁₀ , R ₁₁ and R ₁₂ represent a methyl group or an ethyl group, and Y represents a metal ion.)

Particularly preferred dialkylacrylamides are dimethylacrylamide and diethylacrylamide.
Particularly preferred ionic acrylamide derivatives are 2-acrylamide 2-methylpropanesulfonic acid and its salts.
A particularly preferred cationic acrylamide derivative is N, N, -dimethylaminopropylacrylamide methyl chloride.

  The monomer composition ratio in the polymerization system of the nonionic monomer and the ionic monomer (the charge ratio of the polymerization system) is arbitrarily determined arbitrarily according to the monomer composition ratio of the target microgel. The monomer composition ratio of the microgel and the charging ratio to the polymerization system are almost the same. The charging ratio (molar ratio) of the polymerization system of the nonionic monomer and the ionic monomer is usually nonionic monomer: ionic monomer = 0.5: 9.5 to 9.5: 0.5, preferably 1. : 9 to 9: 1, more preferably 7: 3 to 9: 1. The optimum ratio is nonionic monomer: ionic monomer = 8: 2.

  The above-mentioned water-soluble ethylenically unsaturated monomer is arbitrarily selected and the thickener used in the present invention is polymerized. A particularly preferred thickener is a binary copolymer microgel copolymerized from dimethylacrylamide and 2-acrylamido-2-methylpropanesulfonic acid as water-soluble ethylenically unsaturated monomers. In this case, there is no need for a crosslinking monomer, and a thickener that exhibits an excellent thickening effect and a feeling of use due to self-crosslinking can be obtained. A crosslinking monomer can also be used. In that case, the crosslinking monomer represented by the general formula (4) is preferable, and methylenebisacrylamide is particularly preferable.

  In order to dissolve the water-soluble ethylenically unsaturated monomer in the dispersed phase and polymerize the preferred microgel for the present invention, it is necessary to select the optimum outer phase oil or organic solvent and surfactant. . The present inventor has prepared the hydrophilic-hydrophobic balance (HLB) of the nonionic surfactant to show a cloud point at a temperature suitable for thermal radical polymerization by creating a phase diagram in the composition of the polymerization system. It was found that a microgel having a rheological characteristic preferable as a thickener can be obtained by creating a state of forming a one-phase microemulsion or a fine W / O emulsion at a normal thermal radical polymerization temperature.

Preferred surfactants are polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene hexyl decyl ether, polyoxyethylene isostearyl ether , Polyoxyethylene octyldodecyl ether, polyoxyethylene behenyl ether, polyoxyethylene cholesteryl ether, polyoxyethylene hydrogenated castor oil, sorbitan fatty acid ester, mono fatty acid glycerin, tri fatty acid glycerin, polyglycerin fatty acid ester, isostearic acid polyoxyethylene glycerin, Polyoxyethylene glycerin triisostearate, polyoxymonostearate Ji Ren glycerin distearate, polyoxyethylene glyceryl, and the like tristearate polyoxyethylene glyceryl.
These surfactants can be appropriately combined to adjust to a desired HLB and added to the polymerization system.

  Surprisingly, in the microgel copolymerized with dialkylacrylamide and acrylamide ionic monomer, the spontaneous crosslinking reaction proceeds, especially without the polyfunctional crosslinking monomer being copolymerized as the third component. Self-crosslinked microgels are obtained, which are particularly preferred thickeners for the present invention.

Although the third component polyfunctional crosslinking monomer is not necessary, the microgel used in the present invention can be synthesized even if it is added and copolymerized. The multifunctional crosslinking monomer is preferably a monomer represented by the general formula (4), and can be crosslinked using one or more kinds of crosslinking monomers represented by the general formula (4). It is essential that these crosslinkable monomers can take a crosslinked structure efficiently in a polymerization system of dialkylacrylamide and an ionic acrylamide derivative.










General formula (4)

  Preferred crosslinkable monomers include, for example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, polyoxyethylene diacrylate, polyoxyethylene dimethacrylate, diethylene glycol dimethacrylate, trimethylolpropane triacrylate, N, N′-methylenebisacrylamide, N, N′-ethylenebisacrylamide, triallyl isocyanurate, pentaerythritol dimethacrylate, and the like can be used, and one or more selected from these can be used. In the present invention, N, N′-methylenebisacrylamide is particularly preferably used.

  The molar ratio of the content of 2-acrylamido-2-methylpropanesulfonic acid units and dialkylacrylamide units in the copolymer that is a thickener used in the present invention is usually 2-acrylamido-2-methylpropanesulfonic acid units. : Dialkylacrylamide unit = 0.5: 9.5 to 9.5: 0.5, preferably 1: 9 to 9: 1, and more preferably = 3: 7 to 1: 9. The optimum ratio is 2-acrylamido-2-methylpropanesulfonic acid unit: dialkylacrylamide unit = 2: 8. The viscosity of the thickener used in the present invention is due to the extension of the molecular chain by electrostatic repulsion based on the sulfonyl group which is a strong dissociation group and the spontaneous crosslinking reaction of dialkylacrylamide or the crosslinked structure by a crosslinking monomer, If the content of the 2-acrylamido-2-methylpropanesulfonic acid unit or a salt thereof is less than 5 mol% with respect to the dialkylacrylamide unit, sufficient molecular viscosity may not be obtained, and sufficient viscosity may not be obtained. .

  The use amount of the crosslinkable monomer is preferably in the range of 0.0001 to 2.0 mol% with respect to the total number of moles of 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof and dialkylacrylamide. Thickeners prepared at less than 0.0001 mol% may not have a crosslinking effect. Moreover, when it exceeds 2 mol%, since a crosslinking density is too high and a microgel cannot fully swell, it may not exhibit sufficient thickening effect.

The molecular weight of the microgel used as a thickener in the present invention is about 100,000 to 5,000,000 (average of PEG: measured by GPC), and is adjusted by the viscosity required as the thickener.
The microgel obtained by the above polymerization method has all the rheological properties of the following (1) to (3). The thickener composed of the microgel is obtained by the production method by the polymerization method described above, and is preferably used as a thickener.
(1) The apparent viscosity of a 0.5% (percentage by mass) aqueous dispersion of the microgel is 10,000 mPa · s or more at a shear rate of 1.0 s ⁻¹ .
(2) The apparent viscosity of the 0.5% (percentage by mass) ethanol dispersion of the microgel is 5000 mPa · s or more at a shear rate of 1.0 s ⁻¹ .
(3) The dynamic elastic modulus in a 0.5% (mass percentage) aqueous dispersion or ethanol dispersion of the microgel is G ′> G ″ within a strain of 1% or less and a frequency of 0.01 to 10 Hz.
The apparent viscosity of the water or ethanol dispersion of the microgel is a viscosity at a measurement temperature of 25 ° C. and a shear rate of 1 s ⁻¹ using a cone plate rheometer (MCR-300 manufactured by Paar Rhysica).
The dynamic elastic modulus is the value of the storage elastic modulus (G ') and loss elastic modulus (G ") measured at a measurement temperature of 25 ° C and a strain of 1% or less in the frequency range of 0.1 to 10 Hz using the same measuring device. Means.

The microgel used as a thickener in the present invention can be separated in a powder state through a simple precipitation purification step after polymerization. The microgel separated into a powder form easily disperses in water or ethanol or a mixed solvent of water / ethanol, swells quickly, and functions as a thickener.
In addition, by selecting a strongly acidic monomer (for example, a monomer containing a sulfonic acid residue) as an ionic monomer to be copolymerized with the microgel, an acidic preparation that cannot be thickened with a conventional carboxyvinyl polymer can be obtained. Thickening is also possible.
Furthermore, this microgel can also be used to thicken or gel alcohol, which has been conventionally difficult to thicken or gel. In particular, it exhibits an excellent effect as a thickener for a composition containing a high concentration of alcohol.

  The thickener used in the present invention is used for thickening or gelation, and when blended as a thickener in a skin coloring external preparation composition, exhibits an excellent thickening effect and is excellent in stability. A composition is obtained. Furthermore, the dyeability in the external preparation composition for skin coloring containing DHA, which has been regarded as a problem of conventional thickeners, is greatly improved. Furthermore, it becomes possible to produce an external preparation composition for skin coloring having a very excellent feeling of use.

The external preparation composition for skin coloring of the present invention is produced by blending the above microgel as a thickener into the base of the external preparation composition for skin coloring. The blending amount of the thickener is appropriately determined and not limited depending on the intended external preparation composition for skin coloring. From the viewpoint of usability, the preferable blending amount is 0.01 to 10% (mass percentage), more preferably 0.1 to 5% (mass percentage).
The content of ethanol in the composition is 1 to 70% by mass, preferably 5 to 20% by mass. However, in the case of high blending of 30% by mass or more of ethanol, for example, a stable composition having an excellent thickening effect can be produced even in a product blended by 30 to 50% by mass. In the case of high ethanol blending, the blending amount of the thickener is somewhat larger, and is preferably 0.01 to 10% by mass.

  Moreover, it is preferable to mix | blend so that the viscosity of the composition in 30 degreeC may be 10-100,000 mPa * s. The viscosity of this composition is measured with a BL type viscometer (rotor No. 4, 12 rpm).

  The dihydroxyacetone used in the present invention is a dye called DHA, and is preferably blended in an amount of 0.1 to 7.5% by mass relative to the total amount of the composition. More preferably, it is 0.5-5.0 mass%.

When the composition of the present invention is further mixed with diisopropyl sebacate, the DHA dyeability is further improved. In particular, the durability of dyeing is improved. This dyeing sustaining effect is particularly preferably exhibited in a composition containing ethanol.
The amount of diisopropyl sebacate is appropriately determined in relation to the amount of DHA. 0.1-20 mass% is preferable with respect to the composition whole quantity.

Furthermore, if an ultraviolet absorber is contained, the composition for external use for coloring the skin is preferably used as a sunscreen cosmetic for preventing sunburn while producing healthy skin tanned outdoors.
In particular, as a sunscreen cosmetic of transparent gel or emulsified gel, a product preferable as a self-tanning sunscreen cosmetic imparted with an SPF effect can be provided.

The ultraviolet absorbers are listed below. The blending amount is appropriately determined according to the target SPF value.
(1) Benzoic acid ultraviolet absorbers For example, paraaminobenzoic acid (hereinafter abbreviated as PABA), PABA monoglycerin ester, N, N-dipropoxy PABA ethyl ester, N, N-diethoxy PABA ethyl ester, N, N-dimethyl PABA ethyl ester, N, N-dimethyl PABA butyl ester, N, N-dimethyl PABA ethyl ester and the like.
(2) Anthranilic acid-based UV absorbers such as homomenthyl-N-acetylanthranilate.
(3) Salicylic acid ultraviolet absorbers such as amyl salicylate, menthyl salicylate, homomenthyl salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate, p-isopropanol phenyl salicylate, and the like.
(4) Cinnamic acid UV absorbers For example, octyl cinnamate, ethyl-4-isopropyl cinnamate, methyl-2,5-diisopropyl cinnamate, ethyl-2,4-diisopropyl cinnamate, methyl-2,4- Diisopropyl cinnamate, propyl-p-methoxycinnamate, isopropyl-p-methoxycinnamate, isoamyl-p-methoxycinnamate, octyl-p-methoxycinnamate (2-ethylhexyl-p-methoxycinnamate), 2-ethoxy Ethyl-p-methoxycinnamate, cyclohexyl-p-methoxycinnamate, ethyl-α-cyano-β-phenylcinnamate, 2-ethylhexyl-α-cyano-β-phenylcinnamate, glyceryl mono-2-ethylhexanoyl -Diparamethoxycinnamate.
(5) Triazine-based ultraviolet absorber, for example, bisresorcinyl triazine.
More specifically, bis {[4- (2-ethylhexyloxy) -2-hydroxy] phenyl} -6- (4-methoxyphenyl) 1,3,5-triazine, 2,4,6-tris { 4- (2-ethylhexyloxycarbonyl) anilino} 1,3,5-triazine and the like.
(6) Other UV absorbers For example, 3- (4'-methylbenzylidene) -d, l-camphor, 3-benzylidene-d, l-camphor, 2-phenyl-5-methylbenzoxazole, 2,2 '-Hydroxy-5-methylphenylbenzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2'-hydroxy-5'-methylphenylbenzotriazole, dianisoylmethane, 4-methoxy-4'-t-butyldibenzoylmethane, 5- (3,3-dimethyl-2-norbornylidene) -3-pentan-2-one, pyridazine derivatives such as dimorpholinopyridazinone.

As explained above, the present invention can provide a transparent gel composition. Moreover, the emulsified gel composition emulsified with the surfactant can be provided. These are preferred as high viscosity gel compositions.
High viscosity means that the viscosity of the composition at 30 ° C. is 10 to 100,000 mPa · s, which is preferable in terms of usability. More preferably, it is 3000-50000 mPa * s.
In addition, it has been confirmed by the present inventor that the emulsified gel composition of the present invention is excellent in stability of the emulsified composition also by a rolling test.

A preferred surfactant is a nonionic surfactant. Listed below.
(1) Examples of the lipophilic nonionic surfactant include sorbitan fatty acid esters (for example, sorbitan monooleate, sorbitan monoisostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquioxide). Oleate, sorbitan trioleate, penta-2-ethylhexyl diglycerol sorbitan, tetra-2-ethylhexyl diglycerol sorbitan, etc.); glycerin polyglycerin fatty acids (eg mono-cotton oil fatty acid glycerin, mono-erucic acid glycerin, sesquioleate glycerin) Glyceryl monostearate, α, α′-oleic acid pyroglutamate glycerin, monostearate glycerin malate, etc.); propylene glycol fatty acid esters (eg, monos Propylene glycol tea acrylate, etc.); hardened castor oil derivative; glycerin alkyl ether and the like.
(2) Examples of hydrophilic nonionic surfactants include POE-sorbitan fatty acid esters (for example, POE-sorbitan monooleate, POE-sorbitan monostearate, POE-sorbitan monooleate, POE-sorbitan tetraoleate). POE sorbite fatty acid esters (eg, POE-sorbite monolaurate, POE-sorbite monooleate, POE-sorbite pentaoleate, POE-sorbite monostearate, etc.); POE-glycerin fatty acid esters (eg, POE-glycerol monostearate, POE-glycerol monoisostearate, POE-monooleate such as POE-glycerol triisostearate, etc .; POE-fatty acid esters (eg POE-distearate, POE-monodiolate, ethylene glycol distearate) POE-alkyl ethers (eg POE-lauryl ether, POE-oleyl ether, POE-stearyl ether, POE-behenyl ether, POE-2-octyldodecyl ether, POE-cholestanol ether, etc.); Pluronic type (for example, Pluronic, etc.); POE / POP- Alkyl ethers (for example, POE / POP-cetyl ether, POE / POP-2-decyltetradecyl ether, POE / POP-monobutyl ether, POE / POP-hydrogenated lanolin, POE / POP-glycerin ether); Tetra POE Tetra POP-ethylenediamine condensates (eg Tetronic, etc.); POE-castor oil hardened castor oil derivatives (eg POE-castor oil, POE-hardened castor oil, POE-hardened castor oil monoisostearate, POE- Hardened castor oil triisostearate, POE-hardened castor oil monopyroglutamic acid monoisostearic acid diester, POE-hardened castor oil maleic acid ); POE-beeswax lanolin derivatives (eg POE-sorbite beeswax etc.); alkanolamides (eg coconut oil fatty acid diethanolamide, lauric acid monoethanolamide, fatty acid isopropanolamide etc.); POE-propylene glycol fatty acid ester; POE- Alkylamines; POE-fatty acid amides; sucrose fatty acid esters; alkylethoxydimethylamine oxides; trioleyl phosphoric acid and the like.

The oil components that can be blended in the case of preparing an emulsion composition such as a transparent gel composition or an emulsion gel composition are listed below.
These compositions contain oil and water and are produced according to a conventional method.
(1) Examples of liquid oils include avocado oil, camellia oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, persic oil, wheat germ oil, sasanca oil, castor oil Linseed oil, safflower oil, cottonseed oil, eno oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, snail oil, Japanese kiri oil, jojoba oil, germ oil, triglycerin and the like.
(2) Examples of the solid oil include cocoa butter, coconut oil, hardened coconut oil, palm oil, palm kernel oil, owl kernel oil, hardened oil, owl, and hardened castor oil.
(3) Examples of the wax include beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, ibota wax, whale wax, montan wax, nuka wax, lanolin, kapok wax, lanolin acetate, liquid lanolin, sugarcane wax, lanolin fatty acid isopropyl, hexyl laurate, Examples include reduced lanolin, jojoba wax, hard lanolin, shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, lanolin fatty acid polyethylene glycol, POE hydrogenated lanolin alcohol ether, ceresin, and microcrystalline wax.
(4) Examples of the hydrocarbon oil include liquid paraffin, ozokerite, squalane, pristane, paraffin, squalene, petrolatum and the like.
(5) Examples of higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, undecylenic acid, isostearic acid, linoleic acid, linolenic acid, eicosapentaenoic acid (EPA), docosahexaenoic acid ( DHA) and the like.
(6) Examples of higher alcohols include linear alcohols (eg, lauryl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, myristyl alcohol, oleyl alcohol, cetostearyl alcohol); branched chain alcohols (eg, monostearyl glycerin ether) (Batyl alcohol), 2-decyltetradecinol, lanolin alcohol, cholesterol, phytosterol, hexyldodecanol, isostearyl alcohol, octyldodecanol and the like.
(7) Examples of ester oils include isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, lactic acid Cetyl, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, cholesteryl 12-hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid ester, N-alkylglycol monoisostearate, neocapric dicaprate Pentyl glycol, diisostearyl malate, glycerin di-2-heptylundecanoate, tri-2-ethylhexanoic acid trimethylolpropane, triisostearic acid Limethylolpropane, tetra-2-ethylhexanoic acid pentaerythritol, tri-2-ethylhexanoic acid glycerin, trioctanoic acid glycerin, triisopalmitic acid glycerin, triisostearic acid trimethylolpropane, cetyl 2-ethylhexanoate, 2- Ethylhexyl palmitate, glyceryl trimyristate, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, acetoglyceride, 2-heptylundecyl palmitate, diisobutyl adipate, N-lauroyl-L-glutamic acid -2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-adipate 2- Kishirudeshiru, diisopropyl sebacate, 2-ethylhexyl succinate, and triethyl citrate.
(8) Examples of silicone oils include chain polysiloxanes (for example, dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, etc.); cyclic polysiloxanes (for example, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, Dodecamethylcyclohexasiloxane, etc.) Silicone resin, silicone rubber, various modified polysiloxanes that form a three-dimensional network structure (amino-modified polysiloxane, polyether-modified polysiloxane, alkyl-modified polysiloxane, fluorine-modified polysiloxane, etc.) Etc.

It is also preferable to add a colorant to the external preparation composition for skin coloring of the present invention.
Examples of the colorant include dyes, pigments, pearl agents, and caramel. Dyes are preferred for the transparent gel base. In other bases, it is also preferable to blend pigments, pearl agents, caramels and the like in addition to the dyes. The blending amount is appropriately determined and is not particularly limited.

The external preparation composition for skin coloring of the present invention can be produced by a conventional method by appropriately mixing, in the composition, components that can be usually added to an external preparation for skin according to the dosage form, in addition to the above essential components. The kind and adjustment method of the external preparation composition for skin coloring of the present invention are not particularly limited.
The external preparation composition for skin coloring of the present invention is preferably used as a transparent gel, emulsified gel, cream, emulsion type self-tanning cosmetic.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to these Examples. The blending amounts in the examples are mass% (mass percentage) unless otherwise specified.

  First, a synthesis example of a microgel used as a thickener in the present invention will be described. The microgel obtained in the synthesis example is the thickener of the present invention. The polymers of Comparative Examples 1 and 2 produced under polymerization conditions that do not form a fine W / O emulsion are not thickeners according to the present invention (does not meet the requirements set forth in the claims).

Synthesis example 1
40 g of dimethylacrylamide (manufactured by Kojin) and 9 g of 2-acrylamido-2-methylpropanesulfonic acid (manufactured by Sigma) are dissolved in 250 g of ion-exchanged water and adjusted to pH = 7.0 with sodium hydroxide. To a 1000 ml three-necked flask equipped with a reflux apparatus, 250 g of n-hexane, 8.2 g of polyoxyethylene (3) oleyl ether (Emalex 503, manufactured by Nippon Emulsion) and polyoxyethylene (6) oleyl ether (Emalex 506, 16.4g (made in Japan Emulsion) is mixed and dissolved to replace N ₂ . An aqueous monomer solution is added to the three-necked flask and heated to 65 ° C. to 70 ° C. in an oil bath while stirring under an N ₂ atmosphere. After confirming that the system is in a translucent microemulsion state when the temperature of the system reaches 65 ° C. to 70 ° C., 2 g of ammonium persulfate is added to the polymerization system and polymerization is started. A microgel is formed by maintaining the polymerization system at 65-70 ° C. with stirring for 3 hours. After the polymerization is completed, acetone is added to the microgel suspension to precipitate the microgel, followed by washing with acetone three times to remove residual monomer and surfactant. The precipitate is filtered and dried under reduced pressure to obtain a dried white powdered microgel.

Synthesis example 2
35 g of dimethylacrylamide (manufactured by Kojin) and 17.5 g of 2-acrylamido-2-methylpropanesulfonic acid (manufactured by Sigma) are dissolved in 260 g of ion-exchanged water and adjusted to pH = 7.0 with sodium hydroxide. To a 1000 ml three-necked flask equipped with a reflux apparatus, 260 g of n-hexane, polyoxyethylene (3) oleyl ether (Emalex 503, manufactured by Nippon Emulsion) 8.7 g and polyoxyethylene (6) oleyl ether (Emalex 506, Japanese-made emulsion) 17.6g were mixed and dissolved into the N ₂ to replace. An aqueous monomer solution is added to the three-necked flask and heated to 65 ° C. to 70 ° C. in an oil bath while stirring under an N ₂ atmosphere. After confirming that the system is in a translucent microemulsion state when the temperature of the system reaches 65 ° C. to 70 ° C., 2 g of ammonium persulfate is added to the polymerization system and polymerization is started. A microgel is formed by maintaining the polymerization system at 65-70 ° C. with stirring for 3 hours. After the polymerization is completed, acetone is added to the microgel suspension to precipitate the microgel, followed by washing with acetone three times to remove residual monomer and surfactant. The precipitate is filtered and dried under reduced pressure to obtain a dried white powdered microgel.

Synthesis example 3
30 g of dimethylacrylamide (manufactured by Kojin) and 26.7 g of 2-acrylamido-2-methylpropanesulfonic acid (manufactured by Sigma) are dissolved in 280 g of ion-exchanged water and adjusted to pH = 7.0 with sodium hydroxide. To a 1000 ml three-necked flask equipped with a reflux apparatus, 280 g of n-hexane, 9.4 g of polyoxyethylene (3) oleyl ether (Emalex 503, manufactured by Nippon Emulsion) and polyoxyethylene (6) oleyl ether (Emalex 506, Japanese-made emulsion) 19g were mixed and dissolved into the N ₂ to replace. An aqueous monomer solution is added to the three-necked flask and heated to 65 ° C. to 70 ° C. in an oil bath while stirring under an N ₂ atmosphere. After confirming that the system is in a translucent microemulsion state when the temperature of the system reaches 65 ° C. to 70 ° C., 2 g of ammonium persulfate is added to the polymerization system and polymerization is started. A microgel is formed by maintaining the polymerization system at 65-70 ° C. with stirring for 3 hours. After the polymerization is completed, acetone is added to the microgel suspension to precipitate the microgel, followed by washing with acetone three times to remove residual monomer and surfactant. The precipitate is filtered and dried under reduced pressure to obtain a dried white powdered microgel.

Synthesis example 4
Dissolve 35 g of dimethylacrylamide (manufactured by Kojin), 17.5 g of 2-acrylamide-2-methylpropanesulfonic acid (manufactured by Sigma) and 7 mg of methylenebisacrylamide in 260 g of ion-exchanged water, and adjust the pH to 7.0 with sodium hydroxide. In a 1000 ml three-necked flask equipped with a reflux apparatus, 260 g of n-hexane, polyoxyethylene (3) oleyl ether (Emalex 503, manufactured by Nippon Emulsion) 8.7 g and epolyoxyethylene (6) oleyl ether (Emalex 506) , manufactured by Nippon emulsion) 17.6g were mixed and dissolved into the N ₂ to replace. An aqueous monomer solution is added to the three-necked flask and heated to 65 ° C. to 70 ° C. in an oil bath while stirring under an N ₂ atmosphere. After confirming that the system is in a translucent microemulsion state when the temperature of the system reaches 65 ° C. to 70 ° C., 2 g of ammonium persulfate is added to the polymerization system and polymerization is started. A microgel is formed by maintaining the polymerization system at 65-70 ° C. with stirring for 3 hours. After the polymerization is completed, acetone is added to the microgel suspension to precipitate the microgel, followed by washing with acetone three times to remove residual monomer and surfactant. The precipitate is filtered and dried under reduced pressure to obtain a dried white powdered microgel.

Synthesis example 5
Dissolve 35 g of dimethylacrylamide (manufactured by Kojin), 17.5 g of 2-acrylamide-2-methylpropanesulfonic acid (manufactured by Sigma) and 70 mg of methylenebisacrylamide in 260 g of ion-exchanged water, and adjust the pH to 7.0 with sodium hydroxide. To a 1000 ml three-necked flask equipped with a reflux apparatus, 260 g of n-hexane, polyoxyethylene (3) oleyl ether (Emalex 503, manufactured by Nippon Emulsion) 8.7 g and polyoxyethylene (6) oleyl ether (Emalex 506, Japanese-made emulsion) 17.6g were mixed and dissolved into the N ₂ to replace. An aqueous monomer solution is added to the three-necked flask and heated to 65 ° C. to 70 ° C. in an oil bath while stirring under an N ₂ atmosphere. After confirming that the system is in a translucent microemulsion state when the temperature of the system reaches 65 ° C. to 70 ° C., 2 g of ammonium persulfate is added to the polymerization system and polymerization is started. A microgel is formed by maintaining the polymerization system at 65-70 ° C. with stirring for 3 hours. After the polymerization is completed, acetone is added to the microgel suspension to precipitate the microgel, followed by washing with acetone three times to remove residual monomer and surfactant. The precipitate is filtered and dried under reduced pressure to obtain a dried white powdered microgel.

Synthesis Example 6
Dissolve 35 g of dimethylacrylamide (manufactured by Kojin) and 17.5 g of N, N-dimethylaminopropylacrylamide methyl chloride (manufactured by Kojin) in 260 g of ion-exchanged water. To a 1000 ml three-necked flask equipped with a reflux apparatus, 260 g of n-hexane, polyoxyethylene (3) oleyl ether (Emalex 503, manufactured by Nippon Emulsion) 8.7 g and polyoxyethylene (6) oleyl ether (Emalex 506, Japanese-made emulsion) 17.6g were mixed and dissolved into the N ₂ to replace. An aqueous monomer solution is added to the three-necked flask and heated to 65 ° C. to 70 ° C. in an oil bath while stirring under an N ₂ atmosphere. After confirming that the system is in a translucent microemulsion state when the temperature of the system reaches 65 ° C. to 70 ° C., 2 g of ammonium persulfate is added to the polymerization system and polymerization is started. A microgel is formed by maintaining the polymerization system at 65-70 ° C. with stirring for 3 hours. After the polymerization is completed, acetone is added to the microgel suspension to precipitate the microgel, followed by washing with acetone three times to remove residual monomer and surfactant. The precipitate is filtered and dried under reduced pressure to obtain a dried white powdered microgel.

Synthesis example 7
Dissolve 35 g of dimethylacrylamide (manufactured by Kojin), 17.5 g of N, N-dimethylaminopropylacrylamide methyl chloride (manufactured by Kojin) and 7 mg of methylenebisacrylamide in 260 g of ion-exchanged water. To a 1000 ml three-necked flask equipped with a reflux apparatus, 260 g of n-hexane, polyoxyethylene (3) oleyl ether (Emalex 503, manufactured by Nippon Emulsion) 8.7 g and polyoxyethylene (6) oleyl ether (Emalex 506, Japanese-made emulsion) 17.6g were mixed and dissolved into the N ₂ to replace. An aqueous monomer solution is added to the three-necked flask and heated to 65 ° C. to 70 ° C. in an oil bath while stirring under an N ₂ atmosphere. After confirming that the system is in a translucent microemulsion state when the temperature of the system reaches 65 ° C. to 70 ° C., 2 g of ammonium persulfate is added to the polymerization system and polymerization is started. A microgel is formed by maintaining the polymerization system at 65-70 ° C. with stirring for 3 hours. After the polymerization is completed, acetone is added to the microgel suspension to precipitate the microgel, followed by washing with acetone three times to remove residual monomer and surfactant. The precipitate is filtered and dried under reduced pressure to obtain a dried white powdered microgel.

Comparative Synthesis Example 1
30 g of acrylamide (manufactured by Wako Pure Chemical Industries) and 21.6 g of methacryloxyethyl sulfonic acid (manufactured by Nippon Emulsifier) are dissolved in 260 g of ion-exchanged water. In a 1000 ml three-necked flask equipped with a reflux apparatus, 260 g of n-hexane and 26 g of polyoxyethylene (3) oleyl ether (Emalex 503, manufactured by Nihon Emulsion Co., Ltd.) are mixed, dissolved, and N ₂ substituted. A monomer aqueous solution is added to this three-necked flask and heated to 65-70 ° C. in an oil bath while stirring in an N ₂ atmosphere. When the desired temperature is reached, 2 g of ammonium persulfate is added to the polymerization system to initiate polymerization. To do. A polymer is produced by maintaining the polymerization system at 65-70 ° C. with stirring for 3 hours. After completion of the polymerization, acetone is added to the polymer suspension to precipitate the polymer, followed by washing with acetone three times to remove residual monomers and surfactant. The precipitate is filtered and dried under reduced pressure to obtain a bulk polymer dried product. This is mechanically pulverized by a bead mill to obtain a white powder.

Comparative Synthesis Example 2
30 g of acrylamide (manufactured by Wako Pure Chemical Industries) and 21.6 g of methacryloxyethyl sulfonic acid (manufactured by Nippon Emulsifier) are dissolved in 260 g of ion-exchanged water. In a 1000 ml three-necked flask equipped with a reflux apparatus, 260 g of n-hexane and 26 g of polyoxyethylene (6) oleyl ether (Emalex 506, manufactured by Nihon Emulsion Co., Ltd.) are mixed, dissolved, and N ₂ substituted. A monomer aqueous solution is added to this three-necked flask and heated to 65-70 ° C. in an oil bath while stirring in an N ₂ atmosphere. When the desired temperature is reached, 2 g of ammonium persulfate is added to the polymerization system to initiate polymerization. To do. By maintaining the polymerization system at 65 to 70 ° C. with stirring for 3 hours, an aggregate (gel) is formed. After completion of the polymerization, the aggregate (gel) is washed with acetone three times to remove residual monomers and surfactant. The gel is dried under reduced pressure after filtration to obtain a bulk gel dried product. This is mechanically pulverized by a bead mill to obtain a white powder.

"Dynamic elastic modulus of microgel dispersion"
A characteristic of gels is that their mechanical properties behave “solidly” even though most of their constituents are liquids. On the other hand, even if such a gel is finely pulverized, the mechanical properties viewed macroscopically are maintained. For example, the present inventors compared the mechanical properties of both a bulk gel and a crushed gel for agar gel, and reported that the pulverized microgel qualitatively exhibits the same properties as the bulk gel. (Kaneda, Yanagi Journal of Japanese Society of Rheology vol.30 No.2, 89-94 2002).

That is, it is possible to confirm that the fluid has a microgel shape by measuring the dynamic elastic modulus. In order to clarify such physical properties of the present invention, the dynamic elastic modulus of water and alcohol dispersions was measured. The dynamic elastic modulus was measured at 25 ° C. in a strain 1% frequency range of 0.03 to 3 Hz using a cone-plate rheometer (Paar Physica MCR-300). The microgel obtained in Synthesis Example 2 was dispersed in water, ethanol, and a water-ethanol mixed solution (water: ethanol = 20: 80) at 0.5% (mass percentage), and the result of each dynamic elastic modulus. Are shown in FIG. 3 (water), FIG. 4 (ethanol) and FIG. 5 (water-ethanol mixed solution).
The vertical axis of the graph is the storage elastic modulus G ′ (Pa) and the loss elastic modulus G ″ (Pa), and the horizontal axis is the angular frequency. The value of G ′ is the “solid state property” of the test substance. Shows “liquid properties”. That is, it can be determined semi-quantitatively from this graph that “solid (gel)” if G ′> G ″ and “liquid (sol)” if G ′ <G ”.

It can be seen that both results show a typical gel-like property of G ′ (storage elastic modulus)> G ″ (loss elastic modulus) in the measurement frequency range. It can be seen that the thickening effect is due to the friction of fine microgels that exhibit gel-like or solid properties.
Note that such a gel-like dynamic elastic modulus behavior was not observed in the sample having a low apparent viscosity value at 1 s ⁻¹ .

"Function as an acid-resistant thickener"
A microgel containing sulfonic acid as a copolymerizable monomer can be expected to show a stable thickening effect in a wide pH range. As a synthesis example 2 and a comparative example, the viscosity behavior in each pH region of a 0.5% (mass percentage) aqueous dispersion of sinterene L was examined. In the measurement, the apparent viscosity at a shear rate of 1 s ⁻¹ was measured at 25 ° C. by the same method as in (1) above. The results are shown in FIG. The microgel of Synthesis Example 2 showed a stable thickening effect in the range of pH = 2 to 11.

“Thickening effect, dyeing effect, appearance transparency, base stability, feeling of use of external preparation composition for skin coloring”
As one index showing the thickening effect of the microgel obtained in the synthesis example, the effect of the external preparation composition for skin coloring of the following formulation was examined. The viscosity is the rotor No. of BL type viscometer (VS-A type manufactured by Shibaura System). It was measured at 4 and 12 rpm. The results are shown in Table 1.

Formulations of Examples 1 and 2 and Comparative Examples 1 to 6 (Compounding components) Compounding amount (% by mass)
(1) Remaining amount of ion-exchanged water (2) Ethyl alcohol 0 or 20
(3) Sodium pyrosulfite 0.02
(4) Edetate 0.03
(5) Dihydroxyacetone 5.0
(6) 1,3-butylene glycol 5.0
(7) Methylparaben 0.17
(8) Phenoxyethanol 0.3
(9) Thickener of Table 1 0.7
Total 100

Production method: (2) to (5) were dissolved in (1), and (6) in which (7) and (8) were dissolved was added and mixed. (9) was added and mixed and dissolved to obtain an external composition for skin coloring.

Evaluation in the table is as follows.
(1) Thickening effect Measure viscosity at 30 ° C (BL type viscometer)
Evaluation A: The viscosity is 20000 mPa · s or more.
○: Viscosity is 10000 mPa · s or more and less than 20000 mPa · s Δ: Viscosity is 5000 mPa · s or more and less than 10000 mPa · s ×: Viscosity is less than 5000 mPa · s (2) Average point of sensory evaluation by 4 panelists specializing in refreshing <judgment criteria >
4: Very good 3: Excellent 2: Neither 1: Inferior evaluation ◎: Average score of 3.5 or more ○: Average score of 3 or more and less than 3.5 Δ: Average score of 2 or more 3 Less than x: Average score is less than 2 (3) Average score of sensory evaluation by 4 panelists specializing in dyeing effect <Criteria>
4: Very good 3: Excellent 2: Neither 1: Inferior evaluation ◎: Average score of 3.5 or more ○: Average score of 3 or more and less than 3.5 Δ: Average score of 2 or more 3 Less than x: Average point is less than 2 (4) Appearance transparency Visual evaluation ◎: Excellent transparency ○: Transparency △: Translucent x: Opaque (5) Base stability 50 ° C isothermal layer 2 Visual appearance evaluation after standing for a week ◎: No discoloration ○: Almost no discoloration △: Some discoloration ×: Discoloration

As shown in Comparative Examples 1 and 4, the carboxyvinyl polymer can hardly thicken the composition containing dihydroxyacetone. Moreover, as shown in Comparative Examples 2 and 5, xanthan gum is not excellent in base stability, and the base discolors. Also, as shown in Comparative Example 3 and Comparative Example 6, polyquaternium 37 (a thickener monkey care started in Patent Document 9) is itself a dispersion in oil, so that a transparent base should be prepared. I can't. In contrast, the microgel used in the present invention (Synthesis Example 1) can be sufficiently thickened or gelled even in the dihydroxyacetone blending system, and it has been clarified that the same thickening effect can be obtained even in the alcohol blending system.
Similar effects can be obtained when the thickeners of Synthesis Examples 2 to 7 are used in place of the thickener of Synthesis Example 1.
As in Comparative Examples 3 and 4, Sepigel 305 (thickener disclosed in Patent Documents 7 and 8) is itself a dispersion in oil, and thus a transparent base cannot be prepared. Moreover, Sepigel 305 was not excellent also in base stability, and it confirmed that a base discolored.

"Examples 3 to 5"
An emulsified gel self-tanning cosmetic with the following formulation was prepared according to a conventional method, and the dyeing effect was confirmed in the same manner as in Table 1. In addition, the thickener of a synthesis example confirms all the thickeners of the synthesis examples 1-7.

製造方法：（１）に（２）〜（５）、（１２）を溶解し、（７）を６０℃に加熱し溶解させた（６）を加え、混合した。次に（８）〜（１１）を混合し、皮膚着色用外用組成物を得た。この本組成物に上記試験を行ったところ、優れた染色効果が認められ、このうち実施例５に示すように、セバシン酸ジイソプロピルを配合した組成物は特に染色効果に優れた。また、これらは使用感にも優れ、適度なのびとさっぱりさが認められた。 Emulsified gel composition (compounding component) Blending amount (mass%)
(1) Remaining amount of ion-exchanged water (2) Ethyl alcohol 20
(3) Edetate 0.03
(4) Dihydroxyacetone 5.0
(5) Glycerin 2.0
(6) 1,3-butylene glycol 5.0
(7) Polyoxyethylene polyoxypropylene cetyl ether 2.0
(8) Cyclomethicone 5.0
(9) Diisopropyl sebacate 0.7
(10) Octyl methoxycinnamate 7.5
(11) Fragrance 0.1
(12) Microgel thickener of synthesis example 0.7
Total 100

Production method: (2) to (5) and (12) were dissolved in (1), and (6) dissolved by heating (7) to 60 ° C. was added and mixed. Next, (8) to (11) were mixed to obtain an external composition for coloring the skin. When this test was conducted on this composition, an excellent dyeing effect was observed, and among them, as shown in Example 5, the composition containing diisopropyl sebacate was particularly excellent in the dyeing effect. Moreover, they were excellent in the feeling of use, and moderate stretch and refreshment were recognized.

合計 １００

製造方法：（１）に（２）〜（４）、（６）を溶解させた（５）を加え、混合した。（７）に（８）を溶解後、（９）〜（１４）を加えて６５℃に加熱し、混合溶解した後に、６５℃に加熱した（１）〜（６）の混合組成物に加え、（１５）を混合した後、（１６）を撹拌溶解した。このようにして調製した組成物を室温まで冷却し、皮膚着色用外用組成物（クリーム状セルフタンニング化粧料）を得た。この皮膚着色外用組成物には、紫外線防止効果と高い染色効果が認められた。使用感にも優れ、適度なのびとなめらかさ、しっとりさに優れることが認められた。 "Example 6 Creamy self-tanning cosmetic"
(Blending ingredients) Blending amount (% by mass)

Total 100

Manufacturing method: (5) in which (2) to (4) and (6) were dissolved was added to (1) and mixed. After (8) is dissolved in (7), (9) to (14) are added and heated to 65 ° C., mixed and dissolved, and then added to the mixed composition of (1) to (6) heated to 65 ° C. , (15) were mixed, and then (16) was dissolved by stirring. The composition thus prepared was cooled to room temperature to obtain an external composition for skin coloring (creamy self-tanning cosmetic). This skin coloring composition for external use was found to have an ultraviolet ray preventing effect and a high dyeing effect. It was recognized that it was excellent in feeling of use, moderately smooth, smooth and moist.

"Example 7 emulsified gel self-tanning cosmetic"
(Blending ingredients) Blending amount (% by mass)
Residual amount of ion-exchanged water
Edetate 0.03
Dihydroxyacetone 5.0
Glycerin 2.0
1,3-butylene glycol 5.0
Polyoxyethylene polyoxypropylene cetyl ether 2.0
Cyclomethicone 5.0
Diisopropyl sebacate 0.7
Octyl methoxycinnamate 7.5
Fragrance 0.1
Microgel thickener of Synthesis Example 4 0.7
Total 100
The emulsified gel self-tanning cosmetic obtained by mixing the above components by a conventional method has a refreshing feeling and an excellent dyeing effect.

“Example 8: Transparent gel self-tanning cosmetic”
(Blending ingredients) Blending amount (% by mass)
Remaining amount of ion-exchanged water Sodium pyrosulfite 0.02
Ethyl alcohol 10.0
Edetate 0.03
Dihydroxyacetone 5.0
1,3-butylene glycol 5.0
Methylparaben 0.3
Phenoxyethanol 0.17
Diisopropyl sebacate 0.7
Fragrance 0.1
Dye 0.05
Microgel thickener of Synthesis Example 3 0.7
Total 100
Transparent gel self-tanning cosmetics obtained by mixing the above components by a conventional method are excellent in refreshing feeling and have an excellent dyeing effect.

"Example 9 emulsified gel self-tanning cosmetic"
(Blending ingredients) Blending amount (% by mass)
Remaining amount of ion-exchanged water Ethyl alcohol 15.0
Edetate 0.03
Dihydroxyacetone 5.0
Glycerin 2.0
1,3-butylene glycol 5.0
Polyoxyethylene polyoxypropylene cetyl ether 2.0
Cyclomethicone 5.0
Diisopropyl sebacate 0.7
Octyl methoxycinnamate 7.5
Pearl agent 0.1
Fragrance 0.1
Microgel thickener of Synthesis Example 7 0.7
Total 100
The emulsified gel self-tanning cosmetic obtained by mixing the above components by a conventional method has a refreshing feeling and an excellent dyeing effect.

“Example 10 Transparent gel self-tanning cosmetic”
(Blending ingredients) Blending amount (% by mass)
Remaining amount of ion-exchanged water Sodium pyrosulfite 0.02
Ethyl alcohol 25.0
Edetate 0.03
Dihydroxyacetone 5.0
1,3-butylene glycol 5.0
Methylparaben 0.3
Phenoxyethanol 0.17
Diisopropyl sebacate 0.7
Fragrance 0.1
Microgel thickener of Synthesis Example 6 0.7
Total 100
Transparent gel self-tanning cosmetics obtained by mixing the above components by a conventional method are excellent in refreshing feeling and have an excellent dyeing effect.

"Example 11 emulsified gel self-tanning cosmetic"
(Blending ingredients) Blending amount (% by mass)
Remaining amount of ion-exchanged water Ethyl alcohol 30.0
Edetate 0.03
Dihydroxyacetone 5.0
Glycerin 2.0
1,3-butylene glycol 5.0
Polyoxyethylene polyoxypropylene cetyl ether 2.0
Cyclomethicone 5.0
Diisopropyl sebacate 0.7
Octyl methoxycinnamate 7.5
Pigment 0.1
Fragrance 0.1
Microgel thickener of Synthesis Example 2 0.7
Total 100
The emulsified gel self-tanning cosmetic obtained by mixing the above components by a conventional method has a refreshing feeling and an excellent dyeing effect.

  This invention provides the external preparation composition for skin coloring which mix | blended the novel thickener. Self-tanning cosmetics excellent in thickener effect and dyeing effect can be provided. Moreover, the transparent base excellent in transparency and the emulsification base excellent in stability can be manufactured. Furthermore, the composition which exhibits the outstanding thickening effect also in the external preparation composition for skin coloring which mix | blends ethanol highly is provided.

FIG. 3 is a three-component phase diagram of hexane (indicated by W) / surfactant / water-soluble ethylene monomer aqueous solution (indicated by O). It is a graph showing the dynamic elastic modulus of water. It is a graph showing the dynamic elastic modulus of ethanol. It is a graph showing the dynamic elastic modulus of a water-ethanol mixed solution. It is a graph showing the relationship between a viscosity and pH.

Claims (11)

  In a composition having an organic solvent or oil as a dispersion medium and water as a dispersed phase, a thickener comprising a microgel obtained by dissolving a water-soluble ethylenically unsaturated monomer in the dispersed phase and radical polymerization in the dispersed phase; An external preparation composition for skin coloring containing dihydroxyacetone.   The content of the dihydroxyacetone is 0.1 to 7.5% by mass with respect to the total amount of the composition, and the thickener composed of the microgel is 0.01 to 10% by mass. The external preparation composition for skin coloring according to 1.   Furthermore, 1-70 mass% of ethyl alcohol is contained, The external preparation composition for skin coloring of Claim 1 or 2 characterized by the above-mentioned.   The external preparation composition for skin coloring according to claim 3, wherein the content of the ethyl alcohol is 5.0 to 30% by mass relative to the total amount of the composition.   Furthermore, diisopropyl sebacate is contained, The external preparation composition for skin coloring in any one of Claims 1-4 characterized by the above-mentioned.   Furthermore, an ultraviolet absorber is contained, The external preparation composition for skin coloring in any one of Claims 1-5 characterized by the above-mentioned.   The external preparation composition for skin coloring according to any one of claims 1 to 6, wherein the viscosity of the composition at 30 ° C is 10 to 100,000 mPa · s.   The said composition is a transparent gel composition, The external preparation composition for skin coloring in any one of Claims 1-7 characterized by the above-mentioned.   The external preparation composition for skin coloring according to any one of claims 1 to 7, wherein the composition is an emulsified gel composition emulsified with a surfactant.   The said composition is a self-tanning cosmetic, The external preparation composition for skin coloring in any one of Claims 1-9 characterized by the above-mentioned.   Furthermore, the external preparation composition for skin coloring in any one of Claims 1-10 containing a coloring agent.

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