JP6796949B2 - Manufacturing method of oil-in-water emulsified cosmetics - Google Patents

Description

The present invention relates to a method for producing an oil-in-water emulsified cosmetic.

In recent years, as cosmetics and the like, those having a reduced content of surfactants and those not containing them have been required.
However, in the case of emulsified cosmetics in which the content of the surfactant is reduced or not contained, the emulsified particle size becomes large and sufficient storage stability cannot be obtained. Therefore, various studies have been conducted in order to obtain an emulsion having a reduced content of a surfactant and an emulsion containing no surfactant.

For example, Patent Document 1 discloses that an oil-in-water emulsified cosmetic having excellent storage stability can be obtained by using a specific amphipathic polymer. Patent Document 2 discloses that a vesicle composition having excellent stability against pH change and storage stability can be obtained by using a specific organic acid and sphingosines.

JP-A-2007-63145 Japanese Unexamined Patent Publication No. 2012-214470

However, although the cosmetic of Patent Document 1 does not contain a surfactant, it is essential that it contains a specific amide compound. Further, in Patent Document 2, sphingosines are cationized and act as a surfactant on the acidic side, and a specific organic acid acts as a surfactant on the basic side, and the product includes a low molecular weight surfactant. ing.
The present invention relates to a method for producing an oil-in-water emulsified cosmetic that reduces the emulsified particle size with or without reducing the content of a surfactant. In addition, the refreshing feeling of the skin after application can be improved.

The present inventors prepare a emulsion by combining a compound selected from a specific organic acid salt and a specific fatty acid salt with a specific polymer, and then lower the pH to reduce the content of the surfactant. Alternatively, it has been found that an oil-in-water emulsified cosmetic having a good refreshing feeling can be obtained by reducing the emulsified particle size without containing it.
The surfactant here has a molecular weight of 2000 or less.
Hereinafter, the "oil-in-water emulsified cosmetic" in the present invention is also appropriately simply referred to as "emulsified cosmetic".

The present invention relates to a method for producing an oil-in-water emulsified cosmetic having the following steps.
Step 1:
(A) General formula (1)

(In the formula, R ¹ indicates the residue remaining after removing the hydrogen atom of the hydroxyl group of natural sterine having one hydroxyl group or its hydrogen additive, or the hydroxyl group of bile acid, and R ² has 1 to 24 carbon atoms. represents a divalent hydrocarbon group, M represents an alkali metal, alkaline earth metal, ammonium (NH ₄ ^+), organic ammonium, or basic amino acid)
One or more selected from organic acid salts represented by and fatty acid salts having 12 to 24 carbon atoms.
(B) One or 2 selected from an alkyl-modified polysaccharide polymer, a hydrophilic segment having N-acylalkyleneimine as a repeating unit, a polymer having an organopolysiloxane segment as a constituent unit, and a polyether-modified silicone. More than seed polymer,
Step of mixing (C) an oil agent and (D) a composition containing water to obtain an emulsion,
Step 2:
A step of lowering the pH of the emulsion obtained in step 1.

In the present invention, the component (A) is considered to exist as an organic acid salt or a fatty acid salt in step 1 and function as an anionic surfactant. That is, it is considered that the component (A) is present as an anionic surfactant in the emulsion obtained in step 1.
Then, by lowering the pH in step 2, it is considered that part or all of the component (A) is dissociated into the acid and the salt constituting the component (A), and the acid is incorporated into the oil. As a result, it is considered that the content of the anionic surfactant is reduced or is not contained in the emulsion obtained in step 2.

According to the present invention, the emulsified particle size can be reduced with or without the content of the surfactant, and the oil in water has excellent storage stability at a particularly high temperature and a good refreshing feeling. Molded emulsified cosmetics can be obtained.

(Step 1)
Step 1 of the present invention is a step of mixing a composition containing the components (A), (B), (C) and (D) to obtain an emulsion.

Among the components (A), in the organic acid salt represented by the general formula (1), as the natural sterin having one hydroxyl group represented by R ¹ in the formula, for example, cholesterol, stigmasterol, citosterol, etc. , Campesterol, lanosterol, ergosterol and the like, and among them, cholesterol is preferable from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature.
Further, in the general formula (1), R ² is a divalent hydrocarbon group having 1 to 24 carbon atoms, and examples thereof include a linear or branched alkylene group or an alkenylene group, which reduces the emulsified particle size. From the viewpoint of improving storage stability at high temperatures, the following equation

In the formula, R ³ is preferably a group represented by an alkyl group or an alkenyl group of a linear or branched chain having 6 to 20 carbon atoms (in each case, a carboxyl group is bonded to the * side). To do).

R ³ is a linear or branched 2-hexenyl group, 2-octenyl group, 2-decetter group, 2-dodecenyl group, 2-tetradecenyl group, 2-hexadecenyl group, 2-octadeceny group, 2-eicosenyl group. , Hexyl group, octyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosyl group, etc. Among them, from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature. , 2-Tetradecenyl group, 2-Hexadecenyl group, 2-Ocdecenyl group, 2-Eicosenyl group, Tetradecyl group, Hexadecyl group, Octadecil group, Eicosyl group are preferable, and 2-Hexadecenyl group and 2-Octadecenyl group are more preferable.

Such a compound (1) is produced, for example, by reacting sterines with an alkenyl succinic anhydride or an alkyl succinic anhydride and neutralizing with an alkaline substance according to the method described in JP-A-5-294899. Obtainable.
Specific examples thereof include n-hexadecenyl succinate cholesteryl salt, n-octadecenyl succinate cholesteryl salt, etc., from the viewpoint of reducing the emulsified particle size and improving storage stability at high temperatures. At least one or more selected from n-hexadecenyl succinate cholesteryl salt and n-octadecenyl succinate cholesteryl salt is preferable.

Further, among the component (A), the fatty acid salt having 12 to 24 carbon atoms may be a linear fatty acid salt or a branched fatty acid salt, or may be a saturated fatty acid salt or an unsaturated fatty acid salt. Among the fatty acid salts having 12 to 24 carbon atoms, the number of carbon atoms is preferably 14 to 22, more preferably 16 to 20, and 18 to 20 from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature. More preferred.

The salt of component (A), sodium salts, alkali metal salts such as potassium salts; calcium salts, alkaline earth metal salts such as magnesium salts; ammonium (NH ₄ ⁺⁾ salt; monoethanolamine salts, diethanolamine salts, triethanolamine Organic ammonium salts such as ethanolamine salts; basic amino acid salts such as arginine salts, lysine salts and histidine salts can be mentioned. Among these, at least one or two or more selected from alkali metal salts, organic ammonium salts, and basic amino acid salts are preferable from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperatures, and alkali. At least one or more selected from metal salts and basic amino acid salts is more preferable.

The component (A) can also be contained as a salt by blending the acid constituting the component (A) as an acid and neutralizing it with a base. Bases for neutralizing the component (A) in this case, sodium hydroxide, alkali metal hydroxides such as potassium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide; ammonium (NH ₄ ⁺⁾ Organic ammonium such as monoethanolamine, diethanolamine, triethanolamine; basic amino acids such as arginine, lysine, and histidine can be mentioned.
Of these, at least one or two or more selected from alkali metal hydroxides, organic ammonium, and basic amino acids are preferable from the viewpoint of reducing the emulsified particle size and improving storage stability at high temperatures, and alkali. More preferably, at least one or more selected from metal hydroxides and basic amino acids.

As the component (A), one type or two or more types can be used, and the content thereof is an emulsified cosmetic from the viewpoint of improving the refreshing feeling, suppressing the dripping during application, and reducing the emulsified particle size. The acid content is preferably 0.03 to 6% by mass, more preferably 0.08 to 4% by mass, and even more preferably 0.2 to 2.8% by mass.

Further, in the present invention, the oil-in-water emulsified cosmetic may contain an anionic surfactant other than the component (A). From the viewpoint of reducing the size of the emulsified particles and improving the storage stability at high temperatures, the content ratio of the component (A) in the total anionic surfactant in the oil-in-water emulsified cosmetic is preferably 60% by mass or more. 70% by mass or more is more preferable, 90% by mass or more is further preferable, and 100% by mass is even more preferable.

The polymer of the component (B) is composed of an alkyl-modified polysaccharide polymer, a hydrophilic segment having N-acylalkyleneimine as a repeating unit, a polymer having an organopolysiloxane segment as a constituent unit, and a polyether-modified silicone. One or more selected species.
Examples of the alkyl-modified polysaccharide polymer include hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, sodium carboxymethyl cellulose, stearoxy hydroxypropyl methyl cellulose, laureth-13PG hydroxyethyl cellulose, stearoxy PG hydroxyethyl cellulose sulfonate and the like. Can be mentioned.
Of these, at least selected from hydroxypropylmethyl cellulose, stearoxy hydroxypropyl methyl cellulose, laureth-13PG hydroxyethyl cellulose, and stearoxy PG hydroxyethyl cellulose sulfonate from the viewpoint of reducing the emulsified particle size and improving storage stability at high temperatures. One or more are preferable, and at least one or two or more selected from hydroxypropyl methylcellulose and stearoxy PG hydroxyethyl cellulose sulfonate are more preferable, and both hydroxypropyl methylcellulose and stearoxy PG hydroxyethyl cellulose sulfonate are contained. Is even more preferable.
Examples of commercially available products include Metroz 60SH-4000 (manufactured by Shin-Etsu Chemical Co., Ltd.) as hydroxypropylmethyl cellulose; and Sangelose 60M (manufactured by Daido Kasei Kogyo Co., Ltd.) as stearoxy hydroxypropyl methyl cellulose; Examples of stearoxy PG hydroxyethyl cellulose sulfonate include Poise 310 (manufactured by Kao Corporation).

In a polymer having an N-acylalkyleneimine as a repeating unit and an organopolysiloxane segment as a constituent unit (hereinafter, may be referred to as oxazoline-modified silicone), hydrophilicity having N-acylalkyleneimine as a repeating unit. The mass ratio of the organopolysiloxane segment to the sex segment (hydrophilic segment b with the organopolysiloxane segment a / N-acylalkyleneimine as a repeating unit) reduces the size of the emulsified particle and improves the storage stability at high temperature. From the viewpoint, the range of 45/55 to 75/25 is preferable, 47/53 to 74/26 is more preferable, 48/52 to 73/27 is more preferable, 49/51 to 72/28 is even more preferable, and 50 / 50-70 / 30 is particularly preferable.
In the present invention, the above mass ratio is determined by dissolving the organopolysiloxane used in the present invention in 5% by mass in heavy chloroform and analyzing the alkyl group in the organopolysiloxane segment by nuclear magnetic resonance ( ¹ H-NMR) analysis. Alternatively, it refers to a value obtained from the integral ratio of the phenyl group and the methylene group in the poly (N-acylalkyleneimine) segment.

In the oxazoline-modified silicone, the weight average molecular weight of the organopolysiloxane segment is, for example, 1 × 10 ⁴ or more, preferably 2 × 10 ⁴ or more, from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature. more preferably not more 3.5 × 10 ⁴ or more, for example, a 3 × 10 ⁵ or less, preferably 2 × 10 ⁵ or less, more preferably 1.5 × 10 ⁵ or less.
Since the organopolysiloxane constituting the main chain has the same skeleton as the modified organopolysiloxane which is the raw material compound, the weight average molecular weight of the organopolysiloxane constituting the main chain is abbreviated as the average molecular weight of the modified organopolysiloxane. It is the same.
Here, the weight average molecular weight of the modified organopolysiloxane is a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions.
Column: Super HZ4000 + Super HZ2000 (manufactured by Tosoh)
Eluent: 1 mM triethylamine / THF
Flow rate: 0.35 mL / min
Column temperature: 40 ° C
Detector: UV detector sample: 50 μL

Further, in the oxazoline-modified silicone, the number average molecular weight of the poly (N-acylalkyleneimine) segment is, for example, 5 × 10 ² or more from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature. It is preferably 7 × 10 ² or more, more preferably 8 × 10 ² or more, and for example, 4 × 10 ³ or less, preferably 3.5 × 10 ³ or less, still more preferably 3 × 10 ³ or less. ..
The number average molecular weight of the poly (N-acylalkyleneimine) segment can be measured by a method calculated from the molecular weight and the degree of polymerization of each N-acylalkyleneimine unit or by the above GPC measurement method. In the form, it refers to the number average molecular weight measured by the GPC measurement method.

Specific examples of the oxazoline-modified silicone include those represented by the following general formula (2).

(In the formula, n represents a number of 1 to 5, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, m is the degree of polymerization of the monomer, and represents a number of 1 to 1000, r. Is 10 to 2000 on average, p is 0 to 20 on average, q is 1 to 20 on average, X ^- is a pair ion of quaternary ammonium ion, ethyl sulfate ion, methyl sulfate ion, chlorine ion. , Iodine ion, sulfate ion, p-toluenesulfonate ion or perchlorate ion. Note that a polymerization initiator residue is bound to the N-terminal of the repeating unit of N-acylalkyleneimine.)
As the polymerization initiator, diethylsulfate, dimethylsulfate, hydrochloric acid, hydrogen iodide, sulfuric acid, p-toluenesulfonic acid, perchloric acid and the like are used, and these residues are bonded to the N-terminal after polymerization.

As the oxazoline-modified silicone, N-propionylpolyethylenimine-methylpolysiloxane copolymer (POLYSILICONE-9) is preferable. As POLYSILICONE-9, for example, those described in JP-A-2016-6029 can be used.

Examples of the polyether-modified silicone include those represented by the following general formula (3).

[In the formula, R ^{6 to} R ⁸ and R ^{10 to} R ¹¹ represent a methyl group or a phenyl group, respectively, and R ⁵ , R ⁹ and R ¹² are a methyl group, a phenyl group, or a group R ¹³ (OC _{3), respectively.} H ₆ ) _f (OC ₂ H ₄ ) _g O (CH ₂ ) _h − (R ¹³ indicates a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and f and g are average values of 0 to 35, respectively. , And h indicates a number from 1 to 5). However, at least one of R ⁵ , R ⁹ and R ¹² indicates the group R ¹³ (OC ₃ H ₆ ) _f (OC ₂ H ₄ ) _g O (CH ₂ ) _h −. d and e are average values, d indicates a number from 1 to 200, and e indicates a number from 0 to 50]

As the polyether-modified silicone, at least one or two kinds selected from the polyoxyethylene / methylpolysiloxane copolymer represented by the general formula (3) and the poly (oxyethylene / oxypropylene) / methylpolysiloxane copolymer. The above is preferable, and a polyoxyethylene / methylpolysiloxane copolymer is preferable from the viewpoint of reducing the size of the emulsified particles and improving the storage stability at high temperatures.
Commercially available products include, for example, "KF-6015" (PEG-3 dimethicone), "KF-6019" (PEG-9 dimethicone) sold by Shin-Etsu Chemical Industry Co., Ltd., and Toray Dow Corning Silicone Co., Ltd. Examples thereof include "SH-3775M" (PEG-12 dimethicone), "SH-3771M" (PEG-12 dimethicone), and "SS-2804" (PEG-12 dimethicone).

The component (B) includes a hydrophilic segment having N-acylalkyleneimine as a repeating unit, an alkyl-modified polysaccharide polymer, from the viewpoint of improving storage stability at high temperature and reducing the emulsion particle size. At least one or more selected from polymers having an organopolysiloxane segment as a constituent unit is preferable, and an alkyl-modified polysaccharide-based polymer is more preferable.

As the component (B), one type or two or more types can be used, and the content is 0 in the emulsified cosmetic from the viewpoint of improving the refreshing feeling, the ease of spreading at the time of application, and reducing the emulsified particle size. It is preferably .006 to 2.5% by mass, more preferably 0.008 to 1.0% by mass, more preferably 0.01 to 0.65% by mass, and 0.04 to 0.4% by mass. Mass% is more preferred.

Examples of the oil agent of the component (C) include hydrocarbon oils, ester oils, ether oils, silicone oils, higher alcohols having 10 to 24 carbon atoms, higher fatty acids having 10 to 24 carbon atoms, and the like.

More specifically, examples of the hydrocarbon oil include squalane, liquid paraffin, liquid isoparaffin, heavy liquid isoparaffin and the like. Of these hydrocarbon oils, at least one or two or more selected from liquid paraffin, liquid isoparaffin and squalane are preferable from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature, and the liquid isoparaffin and At least one selected from squalane is more preferred.

Examples of the ester oil include monoester oil, diester oil, triester oil and tetraester oil.
Examples of the monoester oil include monoesters of aliphatic or aromatic monocarboxylic acids or dicarboxylic acids having 2 to 24 carbon atoms, and specific examples thereof include cetyl 2-ethylhexanoate, cetyl octanoate, and isononyl isononanoate. , Isotridecyl isononanoate, hexyl laurate, isopropyl myristate, octyldodecyl myristate, myristyl myristate, 2-hexyldecyl myristate, isopropyl palmitate, octyl palmitate, butyl palmitate 2-hexyldecyl stearate, isocetyl stearate , Isocetyl isostearate, decyl oleate, isodecylbenzoate, octyl methoxycinnamate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, 2-ethylhexyl succinate, 2-hexyldecyl adipate, alkyl benzoate ( C12 to C15) and the like can be mentioned. Among these, at least one selected from isononyl isononanoate, isotridecyl isononanoate, isopropyl myristate and octyl methoxycinnamonate is preferable from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature, and isononan. More preferably, at least one or more selected from isononyl acid acid and isotridecyl isononanoate.

Examples of the diester oil include diesters of dicarboxylic acids having 3 to 18 carbon atoms and difatty acid esters of polyhydric alcohols. Specific examples thereof include propylene glycol dicaprylate, neopentyl glycol dicaprate, glycol distearate, and diisostearic acid. Propylene glycol, glyceryl diisostearate, glyceryl monomylystearate monoisostearate, glycerin di2-heptylundecanoate, di2-ethylhexyl succinate, diisopropyl sebacate, diisostearyl malate, ethylene glycol di2-ethylhexanoate, adipine Examples thereof include diisobutyl acid acid, di-2-heptylundesyl adipate, and di-2-ethylhexyl sebacate. Among these, at least one selected from propylene glycol dicaprylate, neopentyl glycol dicaprate, glycol distearate and propylene glycol diisostearate is selected from the viewpoint of reducing the emulsified particle size and improving storage stability at high temperatures. Preferably, at least one or more selected from propylene glycol dicaprylate and neopentyl glycol dicaprate is more preferable.

Examples of the triester oil include trifatty acid esters of trivalent or higher polyhydric alcohols, and specifically, glycerin trimyristate, glycerin triisopalmitate, glycerin tri2-heptylundecanoate, and trimethyl triethylhexanoate. Examples thereof include propane, trimethylol propane trioctanoate, glycerin tri (capril capric acid), glycerin trioleate, glycerin tri2-ethylhexanoate, glycerin triisostearate, olive oil, and jojoba oil. Among these, tri (caprylic capric acid) glycerin, trioleate glycerin, tri2-ethylhexanoate glycerin and triisostearate glycerin from the viewpoint of reducing the emulsified particle size and improving storage stability at high temperatures. At least one or more selected from the above is preferable, and tri (caprylic capric acid) glycerin is more preferable.

Examples of the tetraester oil include tetrafatty acid esters of tetrahydric or higher polyhydric alcohols, and specifically, tetra (behenic acid / benzoic acid / ethylhexanoic acid) pentaerythlit, tetraethylhexanoic acid pentaerythlit, tetra. Examples thereof include pentaerislit octanate and pentaerislit tetra2-ethylhexanoate. Among these, pentaethylhexanoate pentaerythlit, tetraoctanoate pentaerythlit and tetra2-ethylhexanoate pentaerythlit are selected from the viewpoint of reducing the emulsified particle size and improving storage stability at high temperatures. At least one or more are preferable, and pentaerythlit tetraethylhexanoate is more preferable. Further, it is more preferable that the tetraester oil contains a tetraethylhexanoic acid pentaerythlit.

Examples of the ether oil include dialkyl ether, and specific examples thereof include dihexyl ether, dicaprylyl ether, and cetyl-1,3-dimethylbutyl ether. Among these, at least one or more selected from dicaprylyl ether and cetyl-1,3-dimethylbutyl ether are preferable from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature, and cetyl is preferable. -1,3-Dimethylbutyl ether is more preferable.

Examples of the silicone oil include methylpolysiloxane, crosslinked methylpolysiloxane, reticulated methylpolysiloxane, dimethylpolysiloxane, dimethylcyclopolysiloxane, methylphenylpolysiloxane, and higher alcohol-modified organopolysiloxane. Among these, at least one or more selected from methylpolysiloxane, crosslinked methylpolysiloxane and reticulated methylpolysiloxane from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature. Preferably, methylpolysiloxane is more preferred. Further, it is more preferable that the silicone oil contains methylpolysiloxane.

As the higher alcohol having 10 to 24 carbon atoms, a higher alcohol having 12 to 22 carbon atoms is preferable, and a higher alcohol having 16 to 22 carbon atoms is more preferable, from the viewpoint of reducing the emulsified particle size and further improving the refreshing feeling. Higher alcohols having 18 to 22 carbon atoms are more preferable, and higher alcohols having 18 to 22 carbon atoms are even more preferable.
As the higher fatty acid having 10 to 24 carbon atoms, a higher fatty acid having 12 to 22 carbon atoms is preferable, and a higher fatty acid having 16 to 22 carbon atoms is more preferable, from the viewpoint of reducing the emulsified particle size and further improving the refreshing feeling. Higher fatty acids having 18 to 22 carbon atoms are more preferable.

The oil component (C) is selected from at least hydrocarbon oil, ester oil, silicone oil, and higher alcohol having 10 to 24 carbon atoms from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature. One or more of them are preferable, diester oil is preferable among ester oils, and at least one or more selected from hydrocarbon oils, silicone oils, and higher alcohols having 10 to 24 carbon atoms is more preferable. Further, from the viewpoint of reducing the diameter of the emulsified particles, improving the refreshing feeling, and suppressing dripping when applied to the skin, it is more preferable to contain a higher alcohol having 10 to 24 carbon atoms.

As the component (C), one type or two or more types can be used, and the content is 3 to 35% by mass in the emulsified cosmetic from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature. It is preferably 8 to 28% by mass, more preferably 10 to 18% by mass.

In the present invention, the mass ratio of the component (A) to the component (C) as an acid [[mass of (A) as an acid] / (C)] is a viewpoint of reducing the emulsified particle size and improving the refreshing feeling. Therefore, 0.002 to 0.35 is preferable, 0.020 to 0.30 is more preferable, and 0.030 to 0.25 is further preferable.

The water content of the component (D) is preferably 40 to 95% by mass, more preferably 50 to 92% by mass in the emulsified cosmetic, from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature. It is preferable, and 60 to 88% by mass is more preferable.
The water of the component (D) is preferably used separately in step 1 and step 2.
When water is used in step 1, the content (D1) is preferably 5 to 30% by mass, preferably 8 to 30% by mass, in the emulsified cosmetic from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature. 25% by mass is more preferable, and 10 to 20% by mass is further preferable.
When water in step 2 is used, the content (D2) is the balance, preferably 35 to 90% by mass, more preferably 40 to 80% by mass, and 45 to 75% by mass in the emulsified cosmetic. Is even more preferable.

In step 1, the components containing the components (A), (B), (C) and (D) are mixed to obtain an emulsion.
The method for mixing these components is not particularly limited, and can be carried out by a usual method. For example, an oil phase containing the components (A), (B), and (C) is prepared, an aqueous phase containing the component (D) is prepared, and the oil phase is added to the aqueous phase and mixed to form an emulsion. Obtainable.

The emulsion obtained in step 1 is preferably pH 7.5 or higher, more preferably pH 8.0 or higher, further preferably pH 8.3 or higher, and more preferably pH 8.8 or higher, from the viewpoint of reducing the emulsified particle size. More preferred. Further, from the viewpoint of reducing the emulsified particle size, pH 12.5 or less is preferable, pH 12.0 or less is more preferable, and pH 11.6 or less is further preferable.
In the present invention, the pH is measured at 25 ° C. using a pH meter (manufactured by HORIBA, Ltd., model number F-22).
It can be confirmed from the experiment of pH and emulsified particle size shown in Reference Example 1 below that the pH of the emulsion obtained in step 1 is preferably 7.5 or more.

(Step 2)
Step 2 is a step of lowering the pH of the emulsion obtained in Step 1.
In step 1, after obtaining an emulsion having a small emulsified particle size, the content of the component (A) can be reduced or not contained by lowering the pH, and the emulsified particle size remains small. Therefore, it is considered that an oil-in-water emulsified cosmetic having excellent storage stability at high temperature can be obtained.
In step 2, in order to lower the pH, it is preferable to add the pH lowering component (E) to the emulsion obtained in step 1 and then mix the mixture to lower the pH.

As the component (E) for lowering the pH, one or more selected from an acidic polymer having a structural unit derived from an inorganic acid, an organic acid having 8 or less carbon atoms, an acrylic acid or a sulfonic acid is preferable.
Examples of the inorganic acid include hydrochloric acid, nitrate, nitrite, sulfuric acid, sulfite, phosphoric acid, phosphonic acid, and phosphinic acid, and at least one selected from phosphoric acid, phosphonic acid, and phosphinic acid from the viewpoint of reducing the emulsified particle size. Species or two or more are preferable, at least one or two or more selected from phosphoric acid and phosphonic acid are more preferable, and phosphoric acid is further preferable.

Examples of organic acids having 8 or less carbon atoms include monocarboxylic acids such as acetic acid, propionic acid and butyric acid; dicarboxylic acids such as succinic acid, phthalic acid, fumaric acid, oxalic acid, malonic acid and glutaric acid; glycolic acid, citric acid, etc. Oxycarboxylic acids such as lactic acid, pyruvate, malic acid and tartrate; acidic amino acids such as glutamic acid and aspartic acid can be mentioned, and at least one selected from monocarboxylic acid, dicarboxylic acid and acidic amino acid from the viewpoint of reducing the emulsified particle size. Species or two or more are preferable, at least one or two or more selected from dicarboxylic acids and acidic amino acids are more preferable, and acidic amino acids are even more preferable.

Examples of the acidic polymer having a structural unit derived from acrylic acid or sulfonic acid include a carboxyvinyl polymer, an alkyl-modified carboxyvinyl polymer, a polyacrylic acid, at least an acrylate or a hydroxyalkyl acrylate, and an acryloyldimethyltaurine salt. Examples thereof include copolymers obtained by copolymerization, and from the viewpoint of reducing the emulsified particle size, carboxyvinyl polymers, alkyl-modified carboxyvinyl polymers and polyacrylic acids are preferable, and carboxyvinyl polymers and alkyl-modified carboxys are preferable. Vinyl polymers are more preferred.

As the component (E), an acidic polymer having a structural unit derived from acrylic acid or sulfonic acid is preferable from the viewpoint of reducing the diameter of the emulsified particles and suppressing dripping during coating.
As the component (E), one type or two or more types can be used, and the content is 0.01 to 0.01 in the emulsified cosmetic from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature. It is preferably 2% by mass, more preferably 0.015 to 1.5% by mass, and even more preferably 0.02 to 1.2% by mass.
When the component (E) contains an acidic polymer having a structural unit derived from acrylic acid or sulfonic acid, the content is emulsified from the viewpoint of reducing the emulsified particle size and improving the ease of spreading during application. It is preferably 0.05 to 0.7% by mass, more preferably 0.06 to 0.4% by mass, and even more preferably 0.08 to 0.3% by mass in the cosmetic.

In step 2, when the component (E) is added to the emulsion obtained in step 1, the component (E) is previously added from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperature. It is preferable to add the component (D) by mixing it with a part of water (D2).
In step 2, it is preferable to lower the pH of the emulsion obtained in step 1 by adding the component (E).
The emulsion obtained in step 2 preferably has a pH of less than 7.5, more preferably pH 7.4 or less, and a pH of 7.3 or less, from the viewpoint of reducing the emulsified particle size and improving the storage stability at high temperatures. Is even more preferable. Further, pH 2.6 or higher is preferable, pH 2.7 or higher is more preferable, and pH 2.8 or higher is even more preferable.
The pH is measured by the same method as the measurement of the pH of the emulsion in step 1.

The rate of change in the difference between the pH of the emulsion obtained in step 1 and the pH of the emulsion obtained in step 2, [[(pH of emulsion in step 1)-(pH of emulsion in step 2)] / ( The pH of the emulsion in step 1)] is preferably 0.18 to 0.80, preferably 0.22 to 0.77, from the viewpoint of reducing the emulsion particle size and improving the storage stability at high temperatures. Is more preferable, and 0.25 to 0.74 is even more preferable.

The oil-in-water emulsified cosmetic obtained in this manner preferably has an emulsified particle size (D50) of 1 to 10 μm, more preferably 1 to 9 μm.
In the present invention, the emulsified particle size is the volume particle size measured by a laser diffraction / scattering type particle size distribution measuring device (Partica LA-950V2, manufactured by HORIBA). The emulsified particle size (D50) is a particle size in which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle size. Similarly, the emulsified particle size (D90) is a volume. The cumulative volume frequency calculated by fraction is 90% calculated from the smaller particle size.

Further, the oil-in-water emulsified cosmetic obtained by the present invention has a viscosity at 25 ° C. of 900 to 35,000 mPa. From the viewpoint of suppressing dripping when applied to the skin and improving the ease of spreading during application. It is preferably s, more preferably 4,000 to 30,000 mPa · s, further preferably 8,000 to 24,000 mPa · s, even more preferably 10,000 to 16,000 mPa · s.
In the present invention, the viscosity is measured using a B-type viscometer (TVB-10R type rotational viscometer, manufactured by Toki Sangyo Co., Ltd., rotor No. 4, 6 rpm, 25 ° C.).

In addition to the above-mentioned components, the oil-in-water emulsified cosmetic obtained by the present invention further contains components used in ordinary cosmetics, such as alcohols having 1 to 3 carbon atoms, moisturizers, antioxidants, preservatives, and cold sweats. Agents, chelating agents, whitening agents, ultraviolet absorbers, vitamins, plant extracts, various other medicinal ingredients, powders, fragrances, coloring materials, etc. can be blended. Each of these agents is not limited to the use as each agent, and may be used for other purposes depending on the purpose, for example, a cooling sensation agent may be used as a fragrance, or in combination with other applications, for example, an antiperspirant and a fragrance. It can be used as one that produces the effect of.
The oil-in-water emulsified cosmetic of the present invention can be applied to, and preferably applied to, the skin, especially the skin excluding hair, preferably the face, body, limbs, and the like.

Reference Example 1 (Experiment of pH and emulsified particle size)
An emulsion having the composition shown in Table 1 was produced, and the pH and emulsion particle size (D50) were measured. The results are shown in Table 2.
(Manufacturing method of emulsion)
At 80 ° C., liquid paraffin and oleic acid were mixed at disper 3000 rpm for 5 minutes to prepare an oil phase. An aqueous phase was prepared by mixing potassium hydroxide and water. An aqueous phase was added to the oil phase, and the mixture was mixed at disper 3000 rpm for 5 minutes, and further mixed at a homomixer 7000 rpm for 1 minute. Then, while mixing with a propeller stirrer at 300 rpm, the mixture was cooled to 25 ° C. at a speed of 1 ° C./min to obtain an emulsion.
The pH and emulsified particle size (D50) of the obtained emulsion were measured.
By changing the content of potassium hydroxide in the emulsion, emulsions having different pH were obtained.

(Measuring method)
(1) pH:
Using a pH meter (manufactured by HORIBA, Ltd., model number F-22), the emulsion was cooled to 25 ° C., and then measured at 25 ° C. 24 hours later.
(2) Emulsified particle size:
For each emulsion, the emulsified particle size (D50) was measured using HORIBA LA-920 (manufactured by HORIBA, Ltd.) by a laser scattering / diffraction method.

From the results in Table 2, it can be seen that the emulsified particle size (D50) is small in the pH range of 6.9 to 7.7. Therefore, it was confirmed that the pH of the emulsion obtained in step 1 is preferably 7.5 or higher.

Examples 1 to 3 and Comparative Examples 1 to 8
An oil-in-water emulsified cosmetic having the composition shown in Table 3 was produced, the diameter (D50) and viscosity of the emulsified particles in the oil-in-water emulsified cosmetic were measured, and the storage stability and refreshing feeling were evaluated. The results are also shown in Table 3.
The pH of the emulsion obtained in step 1 and the emulsion obtained in step 2 was measured at 25 ° C. using a pH meter (manufactured by HORIBA, Ltd., model number F-22). The emulsion obtained in step 2 was measured 24 hours after production.

(Production method)
(1) Example 1:
(Step 1)
At 80 ° C., cholesteryl n-octadecenyl succinate, cholesteryl n-hexadecenyl succinate, components (B) and (C) were mixed at disper 3000 rpm for 5 minutes to prepare an oil phase. Then, potassium hydroxide and a part of water (D1) were mixed to prepare an aqueous phase. Then, the aqueous phase was added to the oil phase and mixed at disper 3000 rpm for 10 minutes, and further mixed at homomixer 7000 rpm for 10 minutes. Then, while mixing with a propeller stirrer at 300 rpm, the mixture was cooled to 25 ° C. at a speed of 1 ° C./1/1 minute to obtain an emulsion having a pH of 8.5.
(Step 2)
An aqueous phase in which the component (E) and the remaining component (D2) are mixed is further added to the pH 8.5 emulsion obtained in step 1, and the mixture is mixed with a propeller stirrer at 300 rpm for 5 minutes to make water at pH 5.5. An oil-type emulsified cosmetic was obtained.
In step 1, cholesteryl n-octadecenyl succinate and cholesteryl n-hexadecenyl succinate form a salt with potassium hydroxide in the composition, and n- is a component (A). It is believed to be present as potassium octadecenyl succinate and potassium cholesteryl n-hexadecenyl succinate.

(2) Examples 2 and 3:
Oil-in-water emulsified cosmetics in the same manner as in Example 1 except that cholesteryl n-octadecenyl succinate and cholesteryl n-hexadecenyl succinate were replaced with oleic acid and potassium hydroxide was replaced with L-arginine. I got a fee.

(3) Comparative Example 1:
At 80 ° C., the components (B) and (C) were mixed at disper 3000 rpm for 5 minutes to prepare an oil phase. Then, water heated to 80 ° C. was added to the oil phase, mixed at disper 3000 rpm for 10 minutes, further mixed at homomixer 7000 rpm for 10 minutes, and then mixed with a propeller stirrer 300 rpm at 1 ° C./1. The mixture was cooled to 25 ° C. at a rate of 1 minute to obtain an oil-in-water emulsified cosmetic.

(4) Comparative Examples 2 and 3:
An oil-in-water emulsified cosmetic was obtained in the same manner as in Comparative Example 1.

(5) Comparative Example 4:
At 80 ° C., cholesteryl n-octadecenyl succinate, cholesteryl n-hexadecenyl succinate, and component (C) were mixed at disper 3000 rpm for 5 minutes to prepare an oil phase. An aqueous phase was prepared by mixing potassium hydroxide and water at 80 ° C. Then, the aqueous phase was added to the oil phase and mixed at disper 3000 rpm for 10 minutes, and further mixed at homomixer 7000 rpm for 10 minutes. Then, while mixing with a propeller stirrer 300, the mixture was cooled to 25 ° C. at a speed of 1 ° C./1/1 minute to obtain an oil-in-water emulsified cosmetic.

(6) Comparative Example 5:
Oil-in-water emulsified makeup in the same manner as in Comparative Example 4, except that cholesteryl n-octadecenyl succinate and cholesteryl n-hexadecenyl succinate were replaced with oleic acid and potassium hydroxide was replaced with L-arginine. I got a fee.

(7) Comparative Example 6:
At 80 ° C., cholesteryl n-octadecenyl succinate, cholesteryl n-hexadecenyl succinate, components (B) and (C) were mixed at disper 3000 rpm for 5 minutes to prepare an oil phase. An aqueous phase was prepared by mixing potassium hydroxide and water at 80 ° C. Then, the aqueous phase was added to the oil phase and mixed at disper 3000 rpm for 10 minutes, and further mixed at homomixer 7000 rpm for 10 minutes. Then, while mixing with a propeller stirrer at 300 rpm, the mixture was cooled to 25 ° C. at a speed of 1 ° C./1/1 minute to obtain an oil-in-water emulsified cosmetic.

(8) Comparative Examples 7 and 8:
Oil-in-water emulsified cosmetics in the same manner as in Comparative Example 6 except that cholesteryl n-octadeceenyl succinate and cholesteryl n-hexadecenyl succinate were replaced with oleic acid and potassium hydroxide was replaced with L-arginine. I got a fee.

(Evaluation method)
(1) Emulsified particle size:
The emulsified particle size (D50) of each oil-in-water emulsified cosmetic was measured by a laser scattering / diffraction method using HORIBA LA-920 (manufactured by HORIBA, Ltd.).

(2) Viscosity:
The viscosity of each oil-in-water emulsified cosmetic was measured at 25 ° C. using a B-type viscometer (TVB-10R type rotational viscometer, manufactured by Toki Sangyo Co., Ltd., rotor No. 4, 6 rpm).

(3) Storage stability:
40 g of each oil-in-water emulsified cosmetic was filled in a glass bottle (wide-mouth standard bottle, PS-No. 6, 50 g, manufactured by Tokyo Glass Co., Ltd.), sealed, and stored at 60 ° C. for 2 weeks. After 2 weeks, each emulsified cosmetic was taken out, the appearance was visually observed, and the amount (mm) of the liquid transparently separated into the upper layer or the lower layer of the glass bottle was visually evaluated.

(4) Refreshing feeling:
One expert panelist applied 0.2 g of each oil-in-water emulsified cosmetic to the back of the hand. Then, the skin was massaged for 20 seconds at a rate of once per second in a circle having a diameter of 6 cm, and the skin after the massage was touched with hands to evaluate the refreshing feeling. The evaluation was made on a five-point scale, with 5 being the case of feeling very refreshed and 1 being the case of feeling not refreshing.

Test Example 1 (emulsification confirmation test)
With respect to the oil-in-water emulsified cosmetics (1) obtained in Example 1 and Comparative Example 6, after measuring the emulsified particle diameters (D50) and (D90) by the above method, an oil agent (liquid paraffin 10% by mass). Was added and mixed at 7000 rpm for 1 minute with a homomixer to obtain an oil-in-water emulsified cosmetic (2). For the oil-in-water emulsified cosmetic (2), the emulsified particle diameters (D50) and (D90) were measured in the same manner. The results are shown in Table 4.

In the production method of the present invention, emulsification is performed using an anionic surfactant in step 1. However, in the emulsion finally obtained by lowering the pH of the emulsion in step 2, the anionic surfactant dissociates into an acid and a base, and the acid is incorporated into the emulsified particles as an oil. Anionic surfactants are not present, or even if they are present, they are considered to be in trace amounts.
In order to confirm this, an emulsification confirmation test was conducted in which an oil agent was added to the oil-in-water emulsified cosmetic (1) obtained in the present invention.
The size of the added oil that is emulsified (the size of the oil droplets) is inversely proportional to the amount of the anionic surfactant present in the oil-in-water emulsified cosmetic (1). In the absence of anionic surfactants, the oils separate in the system, and in the presence of only trace amounts, the weak activity results in only large oil droplets, resulting in a large average particle size. In particular, the distribution of the emulsified particle size including oil droplets is considered to include a large amount on the large particle size side.
On the other hand, as the amount of the surfactant increases, the activity becomes stronger, so that the size of the oil droplets becomes smaller, and the distribution of the emulsified particle size including the oil droplets is different from the emulsified particle size before the oil agent is added. It is thought to be smaller.
As a result, as shown in Table 4, in Example 1, the emulsified particle size is the median size (D50), and the particle size ratio on the large particle size side is increased (D90), particularly after the addition of the oil agent. (D50) is 3.5 times as much as (D90) is 17 times as much as before addition, and very large oil droplets are formed, that is, there are few activators here. Was confirmed.
On the other hand, in Comparative Example 6, the difference between the emulsified particle diameters (D50) and (D90) before and after the addition of the oil agent was about 1.6 times for (D50) and about 2.2 times for (D90). It was confirmed that the activity was strong, that is, there were many activators.
It is considered that the same applies to other examples.

Examples 4-21
In the same manner as in Examples 1 to 3, oil-in-water emulsified cosmetics having the compositions shown in Tables 5 to 7 were produced, and the emulsified particle size (D50) and viscosity in the oil-in-water emulsified cosmetics were measured, and at the same time. The storage stability and refreshing feeling were evaluated. The results are also shown in Tables 5 to 7.

Claims (5)

A method for producing an oil-in-water emulsified cosmetic having the following steps.
Step 1:
(A) General formula (1)

(In the formula, R ¹ indicates the residue remaining after removing the hydrogen atom of the hydroxyl group of natural sterine having one hydroxyl group or its hydrogen additive, or the hydroxyl group of bile acid, and R ² has 1 to 24 carbon atoms. represents a divalent hydrocarbon group, M represents an alkali metal, alkaline earth metal, ammonium (NH ₄ ^+), organic ammonium, or basic amino acid)
One or more selected from organic acid salts represented by and fatty acid salts having 12 to 24 carbon atoms.
(B) One or 2 selected from an alkyl-modified polysaccharide polymer, a hydrophilic segment having N-acylalkyleneimine as a repeating unit, a polymer having an organopolysiloxane segment as a constituent unit, and a polyether-modified silicone. More than seed polymer,
Step of mixing (C) an oil agent and (D) a composition containing water to obtain an emulsion,
Step 2:
A step of lowering the pH of the emulsion obtained in step 1. The method for producing an oil-in-water emulsified cosmetic according to claim 1, wherein the emulsion obtained in step 1 has a pH of 7.5 or more, and the emulsion obtained in step 2 has a pH of less than 7.5. In step 2, the emulsion obtained in step 1 is selected from one selected from the component (E) inorganic acid, an organic acid having 8 or less carbon atoms, an acidic polymer having a structural unit derived from acrylic acid or sulfonic acid, or The method for producing an oil-in-water emulsified cosmetic according to claim 1 or 2, wherein two or more kinds are added to lower the pH. The method for producing an oil-in-water emulsified cosmetic according to any one of claims 1 to 3, wherein the obtained emulsified particle size (D50) of the oil-in-water emulsified cosmetic is 1 to 10 μm. The method for producing an oil-in-water emulsified cosmetic according to any one of claims 1 to 4, wherein the obtained oil-in-water emulsified cosmetic has a viscosity of 4,000 to 30,000 mPa · s.