α-gel-intermediate composition, and production method for α-gel-containing O/W emulsion cosmetic using said composition

Abstract

The present invention provides an intermediate composition enabling to prepare easily and steadily an -gel-containing O/W emulsion cosmetic that has a very small viscosity change over time and is excellent in emulsion stability, without using a cooling device that has a heavy burden on cost and the environment, and a production method thereof. An -gel intermediate composition consisting of (A) 20 to 80 mass % of a mixture containing one or more higher alcohols having 16 or more carbon atoms and an anionic surfactant in the mole ratio of 3:2 to 5:1, and (B) 20 to 80 mass % of a mixture containing one or more water-soluble solvents having the IOB value of 1.5 to 3.5 and water in the mass ratio of 5:5 to 8:2, and wherein the composition is a liquid consisting of a bicontinuous microemulsion phase or a lamellar liquid crystal-dispersed bicontinuous microemulsion phase at 65 to 85 C. and a solid at room temperature.

Claims

1. An -gel intermediate composition consisting of: (A) 20 to 80 mass % of a mixture of one or more higher alcohols having 16 or more carbon atoms, and an anionic surfactant, in the mole ratio of 3:2 to 5:1, and (B) 20 to 80 mass % of a mixture of one or more water-soluble solvents having an IOB (inorganic organic balance) value of 1.5 to 3.5, and water, in the mass ratio of 5:5 to 8:2, wherein the anionic surfactant is one of more surfactants selected from the group consisting of N-acyl methyl taurine salts, N-acyl glutamic acid salts, and monoalkylphosphoric acid salts; and wherein the composition, when at 65 to 85 C., is a liquid bicontinuous microemulsion or a lamellar liquid crystal-dispersed bicontinuous microemulsion; and wherein the composition, when at room temperature, is a solid.

2. The -gel intermediate composition according to claim 1, wherein: the water-soluble solvent having the IOB value of 1.5 to 3.5 is one or more water-soluble solvents selected from the group consisting of dipropylene glycol, isoprene glycol, 1,3-butanediol, polyethylene glycol, and propylene glycol.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows the results of X-ray diffraction for the composition where water was added to a mixture of behenyl alcohol:sodium N-stearoyl methyl taurine=3:1 (mole ratio) and mixed with stirring at 80 C.

(2) FIG. 2 shows the phase states that the composition containing 30 mass % of the mixture of behenyl alcohol:sodium N-stearoyl methyl taurine=3:1 (mole ratio) and 70 mass % of the mixture of dipropylene glycol/water (mass ratio is plotted on the ordinate) can take at various temperatures.

(3) FIG. 3 shows the phase states that the composition consisting of the mixture of behenyl alcohol:sodium N-stearoyl methyl taurine=3:1 (mole ratio), dipropylene glycol, and water can take at 80 C.

(4) FIG. 4 shows the results of X-ray diffraction after the -gel intermediate composition of Test Example 31 of the present application was stored at room temperature for a few weeks and then heated to 80 C., room-temperature water that is 8 times by mass of the intermediate composition was added, and they were mixed with stirring.

(5) FIG. 5 shows optical micrographs of the -gel-containing O/W emulsion cosmetics prepared by two different production methods even though the formulations are the same (production method of the present invention: Test Example 53 in the present application; conventional production method: Test Example 54 in the present application).

DESCRIPTION OF EMBODIMENTS

(6) Hereinafter, preferable embodiments of the present invention will be explained. At first, the -gel intermediate composition of the present invention and the components thereof will be explained in detail.

(7) PEG, POE, and POP in the following description are abbreviations for polyethylene glycol, polyoxyethylene, and polyoxypropylene, and the numbers after the hyphen in the abbreviations represent the respective average addition mole numbers. DPG is an abbreviation for dipropylene glycol.

(8) -Gel Intermediate Composition

(9) The -gel intermediate composition of the present invention is a composition containing (A) a mixture containing one or more higher alcohols having 16 or more carbon atoms and an anionic surfactant in the mole ratio of 3:2 to 5:1, and (B) a mixture containing one or more water-soluble solvents with the IOB value of 1.5 to 3.5 and water in the mass ratio of 5:5 to 8:2,
with the mass ratio of (A):(B)=20:80 to 80:20, it is a low-viscosity liquid consisting of a bicontinuous microemulsion phase or a lamellar liquid crystal-dispersed bicontinuous microemulsion phase (hereinafter, called a lamellar liquid crystal-dispersed phase in the present application) at 65 to 85 C., and it becomes a waxy solid at room temperature. In the above-described solid state, the long-term storage is possible at room temperature.

(10) Here, the term IOB value (inorganic organic balance) means the ratio of inorganic value and organic value calculated by the organic conception diagram of Makoto Fujita, and it is an indicator of the polarity of organic compounds (Non-Patent Literature 5). The higher the IOB value of an organic compound, the higher the polarity of the compound.

(11) The -gel intermediate composition of the present invention can easily generate an O/W emulsion cosmetic in which the surrounding of the oil phase (namely, emulsion particles) is covered with -gel, when the composition has been heated to 65 to 85 C. and then oil at 85 C. or lower and water at 30 C. or lower are sequentially added to the composition with mixing. Therefore, the -gel intermediate composition of the present invention can be used as an intermediate composition for -gel-containing O/W emulsion cosmetics.

(12) -Gel in the present invention means an aggregate consisting of lamellar bi-layers, where the hexagonal system is the basic unit, which is formed of a linear higher alcohol having 16 or more carbon atoms and an anionic surfactant in the molar ratio of 3:1 (refer to Non-Patent Literature 3, pages 81 to 82). In the X-ray diffraction, -gel shows sharp peaks corresponding to the long spacing of the order of several tens to several hundred A in the small-angle region, where the diffraction angle is about 10 or lower, and a sharp single peak (in the vicinity of 4.15 ) corresponding to the hexagon of the hexagonal system (namely, short spacing) in the wide-angle region, where the diffraction angle is about 10 or more. When compared with lamellar liquid crystals, it is difficult to distinguish -Gel from lamellar liquid crystals by the patterns in the small-angle region. However, the patterns in the wide-angle region is clearly different each other (in the case of lamellar liquid crystals, a halo, namely a broad single peak is obtained in the vicinity of 4.5 ); thus both can easily be distinguished (refer to Non-Patent Literature 4, pages 238-241).

(13) Accordingly, in the present application, when multiple peaks corresponding to the long spacing are obtained in the small-angle region of the X-ray diffraction and a sharp single peak is obtained in the wide-angle region, it is determined to be an -gel-containing composition.

(14) The bicontinuous microemulsion phase, which can be formed from the -gel intermediate composition of the present invention at 65 to 85 C., is a liquid phase of thermodynamically equilibrated one-phase state consisting of repeated bi-layers formed of a higher alcohol having 16 or more carbon atoms and an anionic surfactant oriented so that the respective hydrophilic groups (or lipophilic groups) are in close proximity. Unlike the above-described -gel, there is no regularity in the arrangement of the higher alcohol and the anionic surfactant along the direction of membrane plane of the above-described repeated bi-layers, and the system as a whole shows optical isotropy. It becomes colorless and transparent at around 80 C.; when hydrophilic dye/hydrophobic dye are added, the diffusion of both dyes to the entire system is observed; thus it can easily be confirmed that this is a bicontinuous phase.

(15) The lamellar liquid crystal-dispersed phase, which can be formed from the -gel intermediate composition of the present invention at 65 to 85 C. is a liquid phase in which lamellar liquid crystals are dispersed in the above-described bicontinuous microemulsion phase as a result of local liquid crystallization of the repeated bi-layers. Similarly to the above-described bicontinuous microemulsion phase, it becomes colorless and transparent at around 80 C., and the diffusion of hydrophilic and hydrophobic dyes to the entire system can be observed. However, the phase contains lamellar liquid crystals; therefore, it shows optical anisotropy. Accordingly, when a composition consisting of a lamellar liquid crystal-dispersed phase is centrifuged at a low speed (for example, low-speed centrifugation at about 2000 rpm with a himacCF7D2-type centrifuge manufactured by Hitachi Koki Co., Ltd.), the separation into the optically isotropic upper layer (bicontinuous microemulsion phase) and the optically anisotropic lower layer (the phase in which lamellar liquid crystals are concentrated) takes place; thus it can be easily distinguished from the bicontinuous microemulsion phase. In the present application, the phase in which the percentage of the lower layer is about 5 volume % or lower with respect to the total composition was defined to be a lamellar liquid crystal-dispersed phase.

(16) In the present application, the liquid phase (liquid) consisting of the above-described bicontinuous microemulsion phase and lamellar liquid crystal-dispersed phase is sometimes called low-viscosity liquid phase (liquid). The term low-viscosity is used in contradistinction to that the viscosities of -gel and a lamellar liquid crystal phase are very high (close to a solid).

(17) Higher Alcohols Having 16 or More Carbon Atoms

(18) Higher alcohols having 16 or more carbon atoms and usable as component (A) of the present invention are not limited in particular so far as they can form -gel in water with an anionic surfactant and usable in the fields of cosmetics, pharmaceuticals, and quasi-drugs. Specific examples include cetyl alcohol, cetostearyl alcohol, stearyl alcohol, behenyl alcohol, and butyl alcohol. They are preferably linear higher alcohols having 16 to 24 carbon atoms, and more preferably linear saturated higher alcohols having 16 to 24 carbon atoms. The higher alcohols of the present application include glycerin mono-fatty acid esters.

(19) In the present invention, one or more higher alcohols having 16 or more carbon atoms can be used as component (A).

(20) Anionic Surfactants

(21) The anionic surfactant usable as component (A) of the present invention is preferably one or more surfactants selected from the group consisting of N-acyl methyl taurine salts, N-acyl glutamic acid salts, and monoalkylphosphoric acid salts. Examples of N-acyl methyl taurine salts include coconut oil fatty acid methyl taurine salt, N-caproyl methyl taurine salt, N-lauroyl methyl taurine salt, N-myristoyl methyl taurine salt, N-palmitoyl methyl taurine salt, N-stearoyl methyl taurine salt, and N-oleoyl methyl taurine salt. As the preferable counter ion, sodium, potassium, triethanolamine, ammonia, etc. can be listed. Among them, N-stearoyl methyl taurine salt is preferable in the present invention, and the most preferable is sodium N-stearoyl methyl taurine.

(22) Examples of N-acyl glutamic acid salts include N-cocoyl glutamic acid salt, N-lauroyl glutamic acid salt, N-myristoyl glutamic acid salt, N-palmitoyl glutamic acid salt, N-stearoyl glutamic acid salt, and N-oleoyl glutamic acid salt; as the preferable counter ion, sodium, potassium, triethanolamine, etc. can be listed. Among them, N-stearoyl glutamic acid salt is preferable in the present invention, and the most preferable is sodium N-stearoyl glutamate.

(23) Examples of monoalkylphosphoric acid salts include laurylphosphoric acid salt, myristylphosphoric acid salt, palmitylphosphoric acid salt, stearylphosphoric acid salt; as the preferable counter ion, sodium, potassium, etc. can be listed. Among them, stearylphosphoric acid salt is preferable in the present invention, and sodium stearylphosphate is most preferable.

(24) The mole ratio of a higher alcohol having 16 or more carbon atoms and an anionic surfactant, which are blended as component (A) of the present invention, is preferably 3:2 to 5:1 and most preferably 3:1. That is because when the mole ratio of the above-described higher alcohol and the anionic surfactant is within the range of 3:2 to 5:1, -gel is known to be effectively formed.

(25) When the rate of the anionic surfactant is higher than the above-described mole ratio, -gel may not be sufficiently formed on the surrounding of oil droplets of the O/W emulsion cosmetic, and when the rate of the higher alcohol is higher, crystals of the higher alcohol may be generated in the emulsion cosmetic.

(26) Water-Soluable Solvents with the IOB Value of 1.5 to 3.5

(27) The water-soluble solvents with the IOB value of 1.5 to 3.5, usable as component (B) in the present invention, are not limited in particular so far as they are commonly used in cosmetics. However, one or more water-soluble solvents selected from the group consisting of dipropylene glycol (IOB=1.80), isoprene glycol (IOB=2.20), 1,3-butanediol (IOB=2.50), 1,4-butanediol (IOB=2.50), polyethylene glycol having the average molecular weight of 300 or lower (for example, PEG-200 with IOB=2.92), and propylene glycol (IOB=3.33) are preferable. Among them, dipropylene glycol, isoprene glycol, 1,3-butanediol, PEG-200, and propylene glycol are more preferable, and dipropylene glycol, 1,3-butanediol, and propylene glycol are most preferable.

(28) In the present invention, one or more water-soluble solvents with the IOB value of 1.5 to 3.5 can be used as component (B).

(29) In the -gel intermediate composition of the present invention, the blending ratio of the above-described component (A) and component (B) is preferably (A):(B)=20:80 to 80:20 in the mass ratio. If (A) is less than 20 mass %, the feeling in use of the O/W emulsion cosmetic tends to be poor. If (A) is more than 80 mass %, a bicontinuous microemulsion phase or a lamellar liquid crystal-dispersed phase may not be formed.

(30) In the following, oil and water blendable in the -gel-containing O/W emulsion cosmetic of the present invention will be explained. These are the components that become the internal phase and the external phase of the -gel-containing O/W emulsion cosmetic of the present invention after adding them to the above-described -gel intermediate composition.

(31) Oil

(32) In the present invention, the oil blendable as the inner layer of the -gel-containing O/W emulsion cosmetic is not limited in particular. Examples include liquid oils and fats, solid oils and fats, waxes, hydrocarbon oils, higher fatty acids, synthetic ester oils, silicone oils, and some higher alcohols (includes those usable as component (A) in the present application). The blending quantity of the oil is not limited in particular; however, it is preferable to be 1 to 50 mass % with respect to the -gel-containing O/W emulsion cosmetic. Outside of the range, the feeling in use may become poor.

(33) Examples of liquid oils and fats include avocado oil, camellia oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg oil, sesame oil, persic oil, wheat germ oil, sasanqua oil, castor oil, linseed oil, safflower oil, cotton seed oil, perilla oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, china paulownia oil, Japanese paulownia oil, jojoba oil, germ oil, and triglycerin.

(34) Examples of solid oils and fats include cacao butter, coconut oil, horse fat, hydrogenated coconut oil, palm oil, beef tallow, mutton tallow, hydrogenated beef tallow, palm kernel oil, lard, beef bone fat, Japan wax kernel oil, hydrogenated oil, beef leg tallow, Japan wax, and hydrogenated castor oil.

(35) Examples of waxes include beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, ibota wax, whale wax, montan wax, rice bran wax, lanolin, kapok wax, acetylated lanolin, liquid lanolin, sugarcane wax, isopropyl lanolin fatty acid, hexyl laurate, hydrogenated 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, and cetyl palmitate.

(36) Example of hydrocarbon oils include liquid paraffin, ozokerite, squalane, pristane, paraffin, ceresin, squalene, petrolatum, and microcrystalline wax.

(37) Examples of higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, undecylenic acid, tall oil acid, isostearic acid, linoleic acid, linolenic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

(38) Examples of synthetic ester oils include cetyl octanoate, myristyl myristate, glyceryl tri-2-ethylhexanoate, pentaerythritol tetra-2-ethylhexanoate, dioctyl succinate, and tripropylene glycol dineopentanoate.

(39) Examples of silicone oils include linear polysiloxanes (for example, dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, etc.); cyclic polysiloxanes (for example, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, etc.), silicone resins with a three-dimensional network, silicone rubbers, various modified polysiloxanes (amino-modified polysiloxane, polyether-modified polysiloxane, alkyl-modified polysiloxane, fluorine-modified polysiloxane, etc.), and acrylsilicones.

(40) Water

(41) In the present invention, water that can be added to the -gel intermediate composition, as the external phase of the -gel-containing O/W emulsion cosmetic, is preferably water near room temperature. The upper-limit temperature is about 30 C., and the lower-limit temperature is about 15 C. In the present invention, room temperature means 15-30 C.

(42) In addition, water-soluble components among the below-illustrated optional components can be suitably blended into the water within the range that the effect of the present invention is not impaired.

(43) Optional Components

(44) In the -gel-containing O/W emulsion cosmetic of the present invention, in addition to the above-described essential components, components normally used in cosmetics, pharmaceuticals, etc. can be blended within the range that the stability thereof is not affected. Examples of such optional components include powder components, amphoteric surfactants, nonionic surfactants, moisturizers, thickeners, film-forming agents, UV absorbers, metal ion sequestering agents, pH adjusters, skin nutrients, vitamins, antioxidants, antioxidant promoters, and perfumes. These optional components can be suitably blended by dissolving oil-soluble components in the above-described oil that is heated to 85 C. or lower and water-soluble components in the above-described water at 30 C. or lower, respectively. As the optional components, compounds identical to the above-described component (B) can be used.

(45) Examples of powder components include inorganic powders (for example, talc, kaolin, mica, sericite, muscovite, phlogopite, synthetic mica, lepidolite, biotite, vermiculite, bentonite, hectorite, laponite, magnesium carbonate, calcium carbonate, aluminum silicate, barium silicate, calcium silicate, magnesium silicate, strontium silicate, tungstic acid metal salts, magnesium, silica, zeolite, barium sulfate, calcined calcium sulfate (calcined gypsum), calcium phosphate, fluorapatite, hydroxyapatite, ceramic powder, metal soaps (for example, zinc myristate, calcium palmitate, aluminum stearate), boron nitride, etc.); organic powders (for example, polyamide resin powder (nylon powder), polyethylene powder, poly(methyl methacrylate) powder, polystyrene powder, styrene-acrylic acid copolymer resin powder, benzoguanamine resin powder, polytetrafluoroethylene powder, cellulose powder, etc.); inorganic white pigments (for example, titanium dioxide, zinc oxide, etc.); inorganic red pigments (for example, iron oxide (bengala), iron titanate, etc.); inorganic brown pigments (for example, -iron oxide etc.); inorganic yellow pigments (for example, yellow iron oxide, yellow ocher, etc.); inorganic black pigments (for example, black iron oxide, low-order titanium oxide, etc.); inorganic violet pigments (for example, mango violet, cobalt violet, etc.); inorganic green pigments (for example, chromium oxide, chromium hydroxide, cobalt titanate, etc.); inorganic blue pigments (for example, ultramarine, Prussian blue, etc.); pearl pigments (for example, titanium oxide-coated mica, titanium oxide-coated bismuth oxychloride, titanium oxide-coated talc, colored titanium oxide-coated mica, bismuth oxychloride, fish scale flake, etc.); metal powder pigments (for example, aluminum powder, copper powder, etc.); organic pigments such as zirconium, barium, or aluminum lakes (for example, organic pigments such as Red No. 201, Red No. 202, Red No. 204, Red No. 205, Red No. 220, Red No. 226, Red No. 228, Red No. 405, Orange No. 203, Orange No. 204, Yellow No. 205, Yellow No. 401 and Blue No. 404; and Red No. 3, Red No. 104, Red No. 106, Red No. 227, Red No. 230, Red No. 401, Red No. 505, Orange No. 205, Yellow No. 4, Yellow No. 5, Yellow No. 202, Yellow No. 203, Green No. 3, Blue No. 1, etc.); and natural dyes (for example, chlorophyll, j-carotene, etc.).

(46) Examples of amphoteric surfactants include imidazoline-type amphoteric surfactants (for example, sodium 2-undecyl-N,N,N-(hydroxyethylcarboxymethyl)-2-imidazoline, 2-cocoyl-2-imidazolinium hydroxide-1-carboxyethyloxy disodium salt, etc.); and betaine-type surfactants (for example, 2-heptadecyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, lauryl dimethylamino acetic acid betaine, alkylbetaines, amidobetaines, sulfobetaines, etc.).

(47) Examples of lipophilic nonionic surfactants include sorbitan fatty acid esters (for example, sorbitan monooleate, sorbitan monoisostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquioleate, sorbitan trioleate, penta-2-ethylhexyl acid diglycerol sorbitan, tetra-2-ethylhexyl acid diglycerol sorbitan, etc.); glycerin polyglycerin fatty acids (for example, glycerin monocottonseed oil fatty acid, glyceryl monoerucate, glyceryl sesquioleate, glyceryl monostearate, glycerin ,-oleic acid pyroglutamic acid, monostearate glycerin malic acid, etc.); propylene glycol fatty acid esters (for example, monostearate propylene glycol, etc.); hydrogenated castor oil derivatives; and glycerin alkyl ethers.

(48) 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, etc.); POE sorbit fatty acid esters (for example, POE-sorbit monolaurate, POE-sorbit monooleate, POE-sorbit pentaoleate, POE-sorbit monostearate, etc.); POE-glycerin fatty acid esters (for example, POE-glycerin monostearate, POE-glycerin monoisostearate, POE-glycerin triisostearate, etc.); POE-fatty acid esters (for example, POE-distearate, POE-monodioleate, ethylene glycol distearate, etc.); POE-alkyl ethers (for example, POE-lauryl ether, POE-oleyl ether, POE-stearyl ether, POE-behenyl ether, POE-2-octyldodecyl ether, POE-cholestanol ether, etc.); Pluronic types (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, etc.); tetraPOE/tetraPOP-ethylenediamine condensation products (for example, Tetronic etc.); POE-castor oil hydrogenated castor oil derivatives (for example, POE-castor oil, POE-hydrogenated castor oil, POE-hydrogenated castor oil monoisostearate, POE-hydrogenated castor oil triisostearate, POE-hydrogenated castor oil monopyroglutamic acid monoisostearic acid diester, POE-hydrogenated castor oil maleic acid, etc.); POE-beeswax/lanolin derivatives (for example, POE-sorbit beeswax etc.); alkanolamide (for example, coconut oil fatty acid diethanolamide, lauric acid monoethanolamide, fatty acid isopropanolamide, etc.); POE-propylene glycol fatty acid ester, POE-alkylamine; POE-fatty acid amide; sucrose fatty acid esters; alkylethoxydimethylamine oxide; and trioleyl phosphate.

(49) In addition, as a thickener, natural/semisynthetic/synthetic polymer compounds can be blended.

(50) Examples of natural water-soluble polymers include plant polymers (for example, gum arabic, tragacanth gum, galactan, guar gum, carob gum, karaya gum, locust bean gum, tamarind gum, carrageenan, pectin, agar, quince seed (marmelo), algecolloid (brown algae extract), starch (rice, corn, potato, wheat), glycyrrhizic acid); microbial polymers (for example, xanthan gum, dextran, succinoglucan, pullulan, etc.); and animal polymers (for example, collagen, casein, albumin, gelatin, etc.).

(51) Examples of semisynthetic water-soluble polymers include starch polymers (for example, carboxymethyl starch, methylhydroxypropyl starch, etc.); cellulose polymers (methylcellulose, ethylcellulose, methylhydroxypropylcellulose, hydroxyethylcellulose, sodium cellulose sulfate, dialkyldimethylammonium sulfate cellulose, hydroxypropylcellulose, carboxymethylcellulose, sodium carboxymethylcellulose, crystalline cellulose, cellulose powder and hydrophobically modified compounds <example: partially stearoxy-modified> of these polymers and cation-modified compounds of these polymers, etc.); alginic acid polymers (for example, sodium alginate, alginic acid propylene glycol ester, etc.); and sodium pectate.

(52) Examples of synthetic water-soluble polymers include vinyl polymers (for example, polyvinyl alcohol, polyvinylmethyl ether, polyvinylpyrrolidone, carboxyvinylpolymer, etc.); polyoxyethylene polymers (for example, polyoxyethylene-polyoxypropylene copolymers of polyethylene glycol 20,000, 40,000, or 60,000, etc.); poly(dimethyldiallylammonium halide)-type cationic polymers (for example, Merquat 100, manufactured by US Merck & Co.); copolymer-type cationic polymers of dimethyldiallylammonium halide and acrylamide (for example, Merquat 550 manufactured by US Merck & Co.); acrylic polymers (for example, sodium polyacrylate, polyethylacrylate, polyacrylamide, etc.); polyethyleneimine; cation polymers; and AlMg silicate (Veegum).

(53) Examples of UV absorbers include benzoic acid-based UV absorber (for example, para-aminobenzoic acid (hereinafter, abbreviated as PABA), PABA monoglycerin ester, N,N-dipropoxyPABA ethyl ester, N,N-diethoxyPABA ethyl ester, N,N-dimethylPABA ethyl ester, N,N-dimethylPABA butyl ester, N,N-dimethylPABA ethyl ester, etc.); anthranilic acid UV absorber (for example, homomenthyl N-acetylanthranilate etc.); salicylic acid UV absorber (for example, amyl salicylate, menthyl salicylate, homomenthyl salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate, p-isopropanolphenyl salicylate, etc.); cinnamic acid UV absorber (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-methoxy cinnamate, isopropyl-p-methoxy cinnamate, isoamyl-p-methoxy cinnamate, octyl-p-methoxy cinnamate (2-ethylhexyl-p-methoxy cinnamate), 2-ethoxyethyl-p-methoxy cinnamate, cyclohexyl-p-methoxycinnamate, ethyl--cyano--phenyl cinnamate, 2-ethylhexyl--cyano--phenyl cinnamate, glyceryl mono-2-ethylhexanoyl-diparamethoxy cinnamate, etc.); benzophenone-type UV absorbers (for example, 2,4-dihydroxybenzophenone, 2,2-dihydroxy-4-methoxybenzophenone, 2,2-dihydroxy-4,4-dimethoxybenzophenone, 2,2,4,4-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4-methylbenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid salt, 4-phenylbenzophenone, 2-ethylhexyl-4-phenyl-benzophenone-2-carboxylate, 2-hydroxy-4-N-octoxybenzophenone, 4-hydroxy-3-carboxybenzophenone, etc.); 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-pentane-2-on, etc.); triazine-type UV absorbers (for example, 2-4[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-4[(2-hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, etc.).

(54) Examples of metal ion sequestering agents include 1-hydroxyethane-1,1-diphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid tetrasodium salt, disodium edetate, trisodium edetate, tetrasodium edetate, sodium citrate, sodium polyphosphate, sodium metaphosphate, gluconic acid, phosphoric acid, citric acid, ascorbic acid, succinic acid, edetic acid, and trisodium ethylenediamine hydroxyethyl triacetate.

(55) Examples of pH adjusters include buffers such as lactic acid-sodium lactate, citric acid-sodium citrate, and succinic acid-sodium succinate.

(56) Examples of vitamins include vitamins A, B1, B2, B6, C, E, and derivatives thereof, pantothenic acid and derivatives thereof, and biotin.

(57) Examples of antioxidants include tocopherols, dibutylhydroxytoluene, butylhydroxyanisole, and gallic acid esters.

(58) Examples of antioxidant promoters include phosphoric acid, citric acid, ascorbic acid, maleic acid, malonic acid, succinic acid, fumaric acid, cephalin, hexametaphosphate, phytic acid, and ethylenediaminetetraacetic acid.

(59) Examples of other blendable components include preservatives (ethyl paraben, butyl paraben, 1,2-alkanediol, phenoxyethanol, methylchloroisothiazolinone, etc.); anti-inflammatory agents (for example, glycyrrhizic acid derivatives, glycyrrhetinic acid derivatives, salicylic acid derivatives, hinokitiol, zinc oxide, allantoin, etc.); whitening agent (for example, saxifraga extract, arbutin, etc.); various extracts (for example, phellodendron bark, coptis rhizome, lithospermum root, peony root, swertia herb, birch, sage, loquat, ginseng, aloe, mallow, iris, grape, coix seed, luffa, lily, saffron, cnidium rhizome, ginger, hypericum, ononis, garlic, capsicum, citrus unshiu peel, Angelica acutiloba, seaweed, etc.), activators (for example, royal jelly, photosensitive elements, cholesterol derivatives, etc.); blood circulation promoters (for example, 4-hydroxy-3-methoxybenzyl nonylic acid amide, nicotinic acid benzyl ester, nicotinic acid -butoxyethyl ester, capsaicin, zingerone, cantharides tincture, ichthammol, tannic acid, -borneol, tocopherol nicotinate, inositol hexanicotinate, cyclandelate, cinnarizine, tolazoline, acetylcholine, verapamil, cepharanthine, -oryzanol, etc.); antiseborrheic agents (for example, sulfur, thianthol, etc.); anti-inflammatory agents (for example, tranexamic acid, thiotaurine, hypotaurine, etc.); aromatic alcohols (benzyl alcohol, benzyloxy ethanol, etc.).

(60) In addition, others such as perfumes and exfoliating agents can be suitably blended within the range that the stability is not impaired.

(61) The -gel-containing O/W emulsion cosmetics of the present invention can be applied, for example, to the body such as skin and hair, and they can be used for skin cosmetics, hair cleanser, skin cleanser, styling agents, etc.

(62) In the following, the production method of an -gel-containing O/W emulsion cosmetic, in which the -gel intermediate composition of the present invention is used, is explained.

(63) Production Method of an -Gel-Containing O/W Emulsion Cosmetic

(64) The above-described -gel intermediate composition is heated to 65 to 85 C., and a low-viscosity liquid phase consisting of a bicontinuous microemulsion phase or a lamellar liquid crystal-dispersed phase is obtained. While stirring the liquid phase, oil that is heated to 85 C. or lower is added. An -gel-containing O/W emulsion cosmetic can be obtained by subsequently carrying out emulsification at room temperature by gradually adding water at 30 C. or lower and continuing stirring until room temperature is reached.

(65) A special device is not necessary in the production process, and a stirring device normally used for the preparation of O/W emulsion cosmetics can be used for the above-described stirring. In addition, the temperature of the composition appropriately decreases by adding water at 30 C. or lower; thus cooling with a cooling device is not necessary. The suitable amount of added water at 30 C. or lower is about 3 to 50 times by mass with respect to the -gel intermediate composition, and preferably about 5 to 25 times by mass.

EXAMPLES

(66) Hereinafter, the present invention will be explained in further detail with reference to examples. However, the scope of the present invention is not limited by these examples. The blending quantities in the present examples are expressed in mass % unless otherwise noted.

Example 1: Preparation of Liquid Phase Wherein -Gel Components are Dissolved without Forming -Gel

(67) A mixture of behenyl alcohol (CH.sub.3(CH.sub.2).sub.21OH, average molecular weight: 306.96) and sodium N-stearoyl methyl taurine (molecular weight: 427.97) in the mole ratio of 3:1 is known to easily form -gel in the presence of water. FIG. 1 shows the results of X-ray diffraction performed at room temperature (25 C.) after water was added to the mixture and mixed at 80 C. by stirring. In the small-angle region, multiple peaks corresponding to the long spacing were detected; in the wide-angle region, a sharp single peak corresponding to the short spacing of about 0.42 nm was detected; thus it is understood that -gel is formed.

(68) Then, various materials were added to the water that dissolves the above-described mixture, and the effect thereof on the formation of -gel was investigated. When dipropylene glycol was added, the formation of -gel was effectively suppressed and a low-viscosity liquid phase without -gel could be obtained. The details are explained below.

(69) Test Composition 1 of the below-described formulation was prepared according to the below-described preparation method, and the temperatures of phase transition/melting were analyzed by carrying out differential scanning calorimetry. The results are shown in FIG. 2; white circles represent temperatures at which an endothermic or exothermic peak was observed and black circles represent temperatures at which a shoulder peak was observed. According to the below-described criteria, the determination of the phase state under the respective conditions was also carried out.

(70) <Formulation/Method of Preparation for Test Composition 1>

(71) The below-described (A) (30 mass %) and (B) (70 mass %) were mixed; it was heated to 80 C. and mixed with stirring.

(72) (A) Behenyl alcohol:sodium N-stearoyl methyl taurine=3:1 (mole ratio) mixture

(73) (B) Mixture of dipropylene glycol:water=1:0 to 0:1 (mass ratio)

(74) <Determination of Phase State>

(75) For the solid, polarizing microscope observation and/or X-ray diffraction was carried out except for the compositions visually determined as a waxy solid (indicated as W-state solid in the table), and the presence or absence of liquid crystals and -gel was determined.

(76) For the liquid phase, the presence or absence of phase separation was visually determined. For the composition without phase separation, the following determination was carried out.

(77) Bicontinuous Microemulsion Phase

(78) If both dyes diffused over the entire composition, when hydrophilic dye and hydrophobic dye were added, and optical anisotropy was not observed under crossed nicols of polarizing microscope observation, the phase was determined as a bicontinuous microemulsion phase.

(79) Liquid Phase Containing a Lamellar Liquid Crystal-Dispersed Phase, a Lamellar Liquid Crystal Phase, and -Gel

(80) If both dyes diffused over the entire composition, when hydrophilic dye and hydrophobic dye were added, and optical anisotropy was observed under crossed nicols of polarizing microscope observation, the composition was further centrifuged at a low speed (low-speed centrifugation at about 2000 rpm with a himacCF7D2-type centrifuge manufactured by Hitachi Koki Co., Ltd.), and the upper layer, which does not show optical anisotropy, and the lower layer, which shows optical anisotropy were separated. X-ray diffraction was carried out for the lower layer, and the presence or absence of liquid crystals and/or -gel was determined. When the lower layer consists of mainly lamellar liquid crystals and the percentage of the lower layer is about 5 volume % or lower of the total composition, the phase was determined to be a lamellar liquid crystal-dispersed phase, and when the percentage of the lower layer is higher than about 5 volume %, the phase was determined as a lamellar liquid crystal phase. If the lower layer mainly comprises -gel, it was determined as a liquid phase containing -gel.

(81) FIG. 2 shows that a mixture containing behenyl alcohol and sodium N-stearoyl methyl taurine in the mole ratio of 3:1 forms -gel, when dissolved in water, under the wide temperature conditions of about 40 to 72 C., and it becomes a lamellar liquid crystal phase at a higher temperature than about 72 C. (in FIG. 2, the ordinate where DPG concentration=0%). On the other hand, when dipropylene glycol was added to the water in which the mixture is dissolved, a lamellar liquid crystal phase was formed at a lower temperature than 72 C., and a lamellar liquid crystal-dispersed phase, instead of a lamellar liquid crystal phase, was eventually formed (range where the concentration of dipropylene glycol is about 20-50%). The percentage of lamellar liquid crystals in the lamellar liquid crystal-dispersed phase decreased with an increase of the concentration of dipropylene glycol. When the concentration of dipropylene glycol was higher than about 50%, a bicontinuous microemulsion phase that does not contain lamellar liquid crystals was found to be formed at about 64 C. or higher.

(82) The black circles in FIG. 2 are known to be, as a result of X-ray diffraction, a thermal change due to the crystallization of behenyl alcohol.

(83) Accordingly, it was clarified that behenyl alcohol and sodium N-stearoyl methyl taurine do not form -gel in an aqueous solution containing 50-80 mass % of dipropylene glycol, at about 64 C. or higher, and can form a low-viscosity liquid phase consisting of a lamellar liquid crystal-dispersed phase or a bicontinuous microemulsion phase.

(84) In addition, the analysis results by varying the mixing ratio of the above-described (A) and (B) (80 C.) are shown in FIG. 3. The shaded region in FIG. 3 is the area of a bicontinuous microemulsion phase or a lamellar liquid crystal-dispersed phase. It was confirmed from the results that even when the content of behenyl alcohol and sodium N-stearoyl methyl taurine (mole ratio: 3:1) was increased to 80 mass %, a low-viscosity liquid phase without -gel could be obtained.

Example 2: Induction of the Formation of -Gel from a Bicontinuous Microemulsion Phase

(85) Next, the induction conditions for the formation of -gel were investigated for the low-viscosity liquid phase without -gel that was obtained in Example 1.

(86) The composition indicated by the arrow in FIG. 2 (namely, Test Composition 1 prepared by using (B) dipropylene glycol:water=6:4 (mass ratio)) became a waxy solid at room temperature. The composition was reverted to a liquid phase by heating to 80 C. after storing for a few weeks at room temperature. The liquid phase was formed of a bicontinuous microemulsion phase, and the presence of -gel was not observed. To this liquid phase, 8 times by mass of ion-exchanged water at room temperature was added and mixed with stirring, and then X-ray diffraction was carried out; the results are shown in FIG. 4. According to FIG. 4, multiple peaks corresponding to the long spacing were detected in the small-angle region, and a sharp single peak corresponding to the short spacing of about 0.42 nm was detected in the wide-angle region; thus it was shown that -gel was formed in the composition.

(87) Accordingly, it was shown that the formation of -gel could easily be induced by diluting the bicontinuous microemulsion phase, which was formed of behenyl alcohol and sodium N-stearoyl methyl taurine in the dipropylene glycol aqueous solution, with water at room temperature.

(88) Thus, it was shown that a low-viscosity liquid phase consisting of the above-described bicontinuous microemulsion phase is an -gel intermediate composition, which generates -gel by the dilution with water at around room temperature, and the -gel intermediate composition can be stably stored as a solid at room temperature. In the present application, the low-viscosity liquid phase consisting of the above-described lamellar liquid crystal-dispersed phase was also confirmed to be an -gel intermediate composition (for example, Test Examples 5 and 7 of the present application).

Example 3: Investigation of Water-Soluable Solvents

(89) Subsequently, kinds of materials that are added to the above-described water were investigated. The below-described Test Composition 2 was prepared by using eight kinds of water-soluble solvents that are structurally similar to dipropylene glycol and blendable in cosmetics, and the phase states at 80 C. and room temperature were determined according to the above-described criteria. The results are shown in Table 1. In the following tables (Tables 1 to 9), the phase state at 80 C. was expressed by the below-described symbols.

(90) : bicontinuous microemulsion phase

(91) : lamellar liquid crystal-dispersed phase

(92) x: phase other than the bicontinuous microemulsion phase or lamellar liquid crystal-dispersed phase

(93) <Formulation/method of preparation for Test Composition 2>

(94) The below-described 30 mass % of (A) and 70 mass % of (B) were mixed, heated to 80 C., and mixed with stirring.

(95) (A) Mixture of Behenyl alcohol:sodium N-stearoyl methyl taurine=3:1 (mole ratio)

(96) (B) Mixture of a water-soluble solvent of Test Examples 1 to 8:water=7:3 (mass ratio)

(97) TABLE-US-00001 TABLE 1 Test Example 1 2 3 4 5 6 7 8 water-soluble Propylene glycol 3-methoxy- Dipropylene Isoprene 1,3- PEG- Propylene Glycerin solvent monopropyl ether 1-butanol glycol glycol butanediol 200 glycol IOB 1.00 1.20 1.80 2.20 2.50 2.92 3.33 5.00 Viscosity* 1.9 2.9 75.0 250.0 95.0 50.0 56.0 14.1 (mPa .Math. s) Phase state of Test Composition 2 80 C. X Room single-phase single-phase W-state W-state W-state W-state W-state Separated temperature transparent transparent solid solid solid solid solid liquid liquid *The value represents the viscosity at 25 C. except for isoprene glycol and propylene glycol, which measured at 20 C..

(98) As shown in Table 1, when propylene glycol monopropyl ether, 3-methoxy-1-butanol, dipropylene glycol, isoprene glycol, 1,3-butanediol, PEG-200, or propylene glycol was used as the above-described water-soluble solvent, a liquid phase consisting of a bicontinuous microemulsion phase or a lamellar liquid crystal-dispersed phase was obtained at 80 C. (Test Examples 1 to 7). However, when glycerin was used, separation to a solid and a liquid took place (Test Example 8). The difference of water-soluble solvents in Test Examples 1 to 7 and a water-soluble solvent in Test Example 8 was investigated. They are indistinguishable by many properties (for example, viscosity etc.); however, if the polarity is focused, they can be distinguished into the following two groups. That is, when a water-soluble solvent with the IOB value of 1.00 to 3.33 (Test Examples 1 to 7) was used, a bicontinuous microemulsion phase or a lamellar liquid crystal-dispersed phase was formed; when glycerin with the IOB of 5.00 was used, separation to a solid and a liquid took place (Test Example 8).

(99) Accordingly, it was suggested from the above-described results that maintaining the polarity of the solvent within a certain range is useful to inhibit the formation of -gel from a higher alcohol having 16 or more carbon atoms and an anionic surfactant and to form a bicontinuous microemulsion phase or a lamellar liquid crystal-dispersed phase.

(100) Furthermore, the above-described Test Composition 2 was cooled to room temperature and the material state was investigated. The composition prepared by using a water-soluble solvent with the IOB value of 1.80 to 3.33 became a white waxy solid (Test Examples 3 to 7). The composition prepared by using propylene glycol monopropyl ether (IOB value=1.00), which has the IOB value lower than the above-described range, or 3-methoxy-1-butanol (IOB value=1.20) stayed being a single-phase transparent liquid (Test Examples 1 and 2).

(101) Thus, it was clarified that in order to prepare an -gel intermediate composition storable at room temperature over a long period, we may dissolve a higher alcohol having 16 or more carbon atoms and an anionic surfactant, with a suitable mole ratio (specifically, 3:2 to 5:1) for the formation of -gel, in an aqueous solution of an water-soluble solvent with the IOB value of 1.5 to 3.5 (for example, dipropylene glycol, isoprene glycol, 1,3-butanediol, PEG-200, propylene glycol, etc.).

Example 4: Investigation of Emulsion Stability of -Gel-Containing Emulsion Cosmetics

(102) In addition, O/W emulsion cosmetics were prepared by using Test Composition 2 prepared in Example 3, and the emulsion stability of the cosmetics were evaluated.

(103) <Production Method of Emulsion Cosmetics>

(104) Test Composition 2 (10 g) prepared in Example 3 was heated to 80 C., and liquid paraffin (10 g) dissolved by heating at 80 C. was added while stirring with a homogenizer. Then, the emulsification was carried out by gradually adding ion-exchanged water (80 g) at room temperature while stirring the mixture with a homogenizer; thus an O/W emulsion cosmetic was obtained.

(105) <Emulsion Stability>

(106) The above-described emulsion cosmetics were stored, in a constant-temperature bath at 25 C., for 1 week, and then the below-described states were determined visually.

(107) : None of creaming, aggregation, or phase separation was observed.

(108) x: One of creaming, aggregation, or phase separation was observed.

(109) TABLE-US-00002 TABLE 2 Test Example 1 2 3 4 5 6 7 8 Water-soluble Propylene glycol 3-methoxy- Dipropylene Isoprene 1,3- PEG- Propylene Glycerin solvent monopropyl ether 1-butanol glycol glycol butanediol 200 glycol IOB 1.00 1.20 1.80 2.20 2.50 2.92 3.33 5.00 Evaluation of the emulsion cosmetics Phase state O/W O/W O/W O/W O/W O/W O/W Separated Emulsion x x x stability

(110) As shown in Table 2, heated oil and water at room temperature were sequentially added to Test Composition 2 prepared by using dipropylene glycol, isoprene glycol, 1,3-butanediol, PEG-200, or propylene glycol aqueous solution, and an O/W emulsion cosmetic excellent in emulsion stability was obtained by mixing with stirring (Test Examples 3 to 7). On the other hand, an O/W emulsion cosmetic was obtained from Test Composition 2 prepared by using propylene glycol monopropyl ether or 3-methoxy-1-butanol aqueous solution; however, the emulsion stability was not satisfactory (Test Examples 1 and 2). From Test Composition 2 of Test Example 8, which separated into two phases, an emulsion could not be obtained. As a result of X-ray diffraction, the presence of -gel was confirmed for the emulsion cosmetics of Test Examples 3 to 7.

(111) Accordingly, a composition consisting of a higher alcohol having 16 or more carbon atoms and an anionic surfactant, with the mole ratio suitable for the formation of -gel (specifically, 3:2 to 5:1), and an aqueous solution of a water-soluble solvent with the IOB value of 1.5 to 3.5 (for example, dipropylene glycol, isoprene glycol, 1,3-butanediol, PEG-200, propylene glycol, etc.); and forms a liquid consisting of a bicontinuous microemulsion phase or a lamellar liquid crystal-dispersed phase under a high temperature (for example, 65 to 80 C.) and becomes a solid at room temperature (namely, -gel intermediate composition of the present invention) was shown to be usable as the intermediate composition to prepare an -gel-containing O/W emulsion cosmetic that is excellent in emulsion stability.

Example 5: Investigation of Kinds of Anionic Surfactants

(112) Next, an investigation was carried out by varying the kinds of anionic surfactants. In the above-described Test Composition 2, sodium N-stearoyl glutamate (Table 3) or sodium monostearyl phosphate (Table 4) was used instead of sodium N-stearoyl methyl taurine to prepare test compositions, and similar analyses were carried out.

(113) TABLE-US-00003 TABLE 3 Anionic surfactant: Sodium N-stearoyl glutamate Test Examples 9 10 11 12 13 14 15 16 Water-soluble Propylene glycol 3-methoxy- Dipropylene Isoprene 1,3- PEG- Propylene Glycerin solvent monopropyl ether 1-butanol glycol glycol butanediol 200 glycol IOB 1.00 1.20 1.80 2.20 2.50 2.92 3.33 5.00 Phase state of the interrnediate composition 80 C. X Room single-phase single-phase W-state W-state W-state W-state W-state Separated temperature transparent transparent solid solid solid solid solid liquid liquid Evaluation of the emulsion cosmetics Phase state O/W O/W O/W O/W O/W O/W O/W Separated Emulsion X X X stability

(114) TABLE-US-00004 TABLE 4 Anionic surfactant: Sodium monostearyl phosphate Test Examples 17 18 19 20 21 22 23 24 Water-soluble Propylene glycol 3-methoxy- Dipropylene Isoprene 1,3- PEG- Propylene Glycerin solvent monaprapyl ether 1-butanol glycol glycol butanediol 200 glycol IOB 1.00 1.20 1.80 2.20 2.50 2.92 3.33 5.00 Phase state of the intemediate composition 80 C. X Room single-phase single-phase W-state W-state W-state W-state W-state Separated temperature transparent transparent solid solid solid solid solid liquid liquid Evaluation of the emulsion cosmetics Phase state O/W O/W O/W O/W O/W O/W O/W Separated Emulsion X X X stability

(115) From Table 3 and Table 4, even when sodium N-stearoyl glutamate (Table 3) or sodium monostearyl phosphate (Table 4) is used as the anionic surfactant, by using 70 mass % aqueous solution of a water-soluble solvent with the IOB value of 1.5 to 3.5 as the solvent, an -gel intermediate composition, which becomes a liquid consisting of a bicontinuous microemulsion phase or a lamellar liquid crystal-dispersed phase under a high temperature and a solid at room temperature, can be obtained (Test Examples 11 to 15 and Test Examples 19 to 23). And an -gel-containing O/W-type emulsion composition excellent in emulsion stability is confirmed to be obtained by sequentially adding heated oil and water at room temperature to the intermediate composition and by mixing with stirring (Test Examples 11 to 15 and Test Examples 19 to 23).

Example 6: Investigation of Concentration of Water-Soluable Solvents

(116) In the above-described Examples 2 to 5, the concentration of a water-soluble solvent was fixed at 70 mass %; thus an investigation was carried out at other concentrations (specifically, 50 to 80 mass %). The results are shown in Tables 5 to 9.

(117) TABLE-US-00005 TABLE 5 Water-soluble solvent: Isoprene glycol (IOB = 2.20) Anionic surfactant Sodium N-stearoyl methyl taurine Sodium monostearyl phosphate Test Example 25 26 4 27 28 29 20 30 Concentration of the water-soluble solvent 50% 60% 70% 80% 50% 60% 70% 80% Intermediate 80 C. composition Room W-state W-state W-state W-state W-state W-state W-state W-state temperature solid solid solid solid solid solid solid solid Emulsion Phase state O/W O/W O/W O/W O/W O/W O/W O/W cosmetics Emulsion stability

(118) TABLE-US-00006 TABLE 6 Water-soluble solvent: Dipropylene glycol (IOB = 1.80) Anionic surfactant Sodium N-stearoyl Sodium N-stearoyl Sodium monostearyl methyl taurine glutamate phosphate Test Example 31 32 33 34 35 36 37 Concentration of the water-soluble solvent 60% 80% 60% 80% 50% 60% 80% Intermediate 80 C. composition Room W-state W-state W-state W-state W-state W-state W-state temperature solid solid solid solid solid solid solid Emulsion Phase state O/W O/W O/W O/W O/W O/W O/W cosmetics Emulsion stability

(119) TABLE-US-00007 TABLE 7 Water-soluble solvent: 1,3-butanediol (IOB = 2.50) Anionic surfactant Sodium N-stearoyl Sodium N-stearoyl Sodium monostearyl methyl taurine glutamate phosphate Test Example 38 39 40 41 42 43 Concentration of the water-soluble solvent 50% 60% 50% 60% 50% 60% Intermediate 80 C. composition Room W-state W-state W-state W-state W-state W-state temperature solid solid solid solid solid solid Emulsion Phase state O/W O/W O/W O/W O/W O/W cosmetics Emulsion stability

(120) TABLE-US-00008 TABLE 8 Water-soluble solvent: PEG-200 (IOB = 2.92) Anionic surfactant Sodium N-stearoyl Sodium N-stearoyl Sodium monostearyl methyl taurine glutamate phosphate Test Example 44 45 46 47 48 49 Concentration of the water-soluble solvent 60% 80% 60% 80% 60% 80% Intermediate 80 C. composition Room W-state W-state W-state W-state W-state W-state temperature solid solid solid solid solid solid Emulsion Phase state O/W O/W O/W O/W O/W O/W cosmetics Emulsion stability

(121) TABLE-US-00009 TABLE 9 Water soluble solvent: Propylene glycol (IOB = 3.33) Anionic surfactant Sodium N-stearoyl Sodium N-stearoyl Sodium monostearyl methyl taurine glutamate phosphate Test Example 7 50 15 51 23 52 Concentration of the water-soluble solvent 70% 80% 70% 80% 70% 80% Intermediate 80 C. composition Room W-state W-state W-state W-state W-state W-state temperature solid solid solid solid solid solid Emulsion Phase state O/W O/W O/W O/W O/W O/W cosmetics Emulsion stability

(122) As shown in Tables 5 to 9 (Test Examples 25 to 52), isoprene glycol, dipropylene glycol, 1,3-butanediol, PEG-200, or propylene glycol, in the range of 50 to 80 mass % aqueous solution, can provide a low-viscosity liquid phase consisting of a bicontinuous microemulsion phase or a dispersed liquid crystal phase by dissolving a higher alcohol having 16 or more carbon atoms and an anionic surfactant, and the low-viscosity liquid phase can become a solid that can be stored for a long term at room temperature. And it was confirmed that -gel-containing O/W emulsion excellent in emulsion stability can be obtained by sequentially adding heated oil and an aqueous phase at room temperature to the low-viscosity liquid phase and by mixing with stirring.

(123) In Test Composition 2 described thus far, the mixing ratio of (A) a mixture containing a higher alcohol having 16 or more carbon atoms and an anionic surfactant in the mole ratio of 3:1 and (B) a mixture containing a water-soluble solvent with the IOB value of 1.80 to 3.33 and water in the mass ratio of 7:3 was fixed at (A):(B)=30:70 (mass ratio); however, similar results were also obtained in a wide range of the mixing ratio (A):(B)=20:80 to 80:20.

(124) Thus, it was clarified that when a mixture containing a water-soluble solvent with the IOB value of 1.5 to 3.5 and water in the mass ratio of 5:5 to 8:2 is used as the solvent, a higher alcohol having 16 or more carbon atoms and an anionic surfactant (though mixed in the mole ratio where -gel can be easily formed) form a bicontinuous microemulsion phase or a dispersed liquid crystal phase instead of -gel and can become a low-viscosity liquid. And it was shown that, by adding oil at 85 C. or lower to the liquid phase and subsequently diluting with water at room temperature, an -gel-containing O/W emulsion cosmetic, in which the surrounding of the oil phase is covered with -gel and thus having excellent emulsion stability, could be stably obtained.

(125) Thus, the -gel intermediate composition of the present invention is an intermediate composition that can easily generate an -gel-containing O/W emulsion cosmetic excellent in emulsion stability by adding heated oil and diluting with water at room temperature.

Example 7: Investigation of Viscosity Stability

(126) As described above, a big issue has been present for the past -gel-containing O/W emulsion cosmetic in that the viscosity gradually increases over time. Thus, the viscosity stability of the -gel-containing O/W emulsion cosmetic prepared by the method of the present invention was compared with the -gel-containing O/W emulsion cosmetic, of the identical formulation, prepared by the conventional method.

(127) <Formulation>

(128) TABLE-US-00010 Components Blending quantity (mass %) Behenyl alcohol 3.3 Stearyl alcohol 0.9 Liquid paraffin 6.0 Glyceryl tri-2-ethylhexanoate 4.0 Sodium N-stearoyl methyl taurine 1.2 Dipropylene glycol 6.5 Glycerin 9.0 1,3-Butylene glycol 5.0 Phenoxyethanol 0.5 Citric acid 0.02 Sodium citrate 0.08 Ion-exchanged water 63.5

Test Example 53: Production Method of the Present Invention

(129) The entire components of the below-described (1) -gel intermediate composition were dissolved at 80 C., and a liquid phase consisting of a colorless, transparent, bicontinuous microemulsion phase was obtained. While stirring the liquid phase with a homogenizer, the below-described (2) oil and oil components (namely, oil phase) dissolved by heating at 80 C. were added, and subsequently the below-described (3) water and aqueous components (namely, the main aqueous phase) that were premixed at room temperature were added little by little. After the completion of addition, deaeration was carried out and an O/W emulsion cream was obtained.

(130) TABLE-US-00011 Components Blending quantity (mass %) (1) -Gel intermediate composition Behenyl alcohol 3.3 Stearyl alcohol 0.9 Sodium N-stearoyl methyl taurine 1.2 Dipropylene glycol 6.5 Ion-exchanged water 1.5 (2) Oil and oil components (oil phase) Liquid paraffin 6.0 Glyceryl tri-2-ethylhexanoate 4.0 (3) Water and aqueous components (main aqueous phase) Glycerin 9.0 1,3-Butylene glycol 5.0 Phenoxyethanol 0.5 Citric acid 0.02 Sodium citrate 0.08 Ion-exchanged water 62.0

Test Example 54: Conventional Production Method (Comparative Example)

(131) The emulsification was carried out by adding the below-described (1) oil and oil components (namely, oil phase) dissolved at 70 C. to the below-described (2) water and aqueous components dissolved by heating at 70 C. (namely, aqueous phase) while stirring the aqueous phase with a homogenizer. Immediately after emulsification, it was cooled to 25 C. while stirring in an ice bath. Then, deaeration was carried out, and an O/W emulsion cream was obtained.

(132) TABLE-US-00012 Components Blending quantity (mass %) (1) Oil and oil components (oil phase) Behenyl alcohol 3.3 Stearyl alcohol 0.9 Liquid paraffin 6.0 Glyceryl tri-2-ethylhexanoate 4.0 (2) Water and aqueous components (aqueous phase) Sodium N-stearoyl methyl taurine 1.2 Dipropylene glycol 6.5 Glycerin 9.0 1,3-Butylene glycol 5.0 Phenoxyethanol 0.5 Citric acid 0.02 Sodium citrate 0.08 Ion-exchanged water 63.5
<Test of Viscosity Stability>

(133) Two kinds of -gel-containing O/W emulsion cosmetics prepared by the above-described method were stored at 0 C., 25 C., 37 C., or 50 C. for 2 months. Immediately after production, after 1 month, and after 2 months, portions of the respective cosmetics were collected and kept warm at 30 C. for 30 minutes. Then, the viscosity was measured with a B-type rotational viscometer (Vismetron viscometer, manufactured by Shibaura Systems Co., Ltd.) (Rotor No. 3, 0.3 or 0.6 rpm, 5 minutes). The results are shown in Table 10.

(134) TABLE-US-00013 TABLE 10 Viscosity stored at each temperature (mPa .Math. s) Production method Storage period 0 C. 25 C. 37 C. 50 C. The present No storage 253200 (100.0%) 253200 (100.0%) 253200 (100.0%) 253200 (100.0%) invention method (immediately (Test example 53) after production) 1 month 244800 (96.7%) 259200 (102.4%) 246000 (97.2%) 238200 (94.1%) 2 months 255800 (101.0%) 261400 (103.2%) 254200 (100.4%) 243200 (96.1%) Conventional No storage 74500 (100.0%) 74500 (100.0%) 74500 (100.0%) 74500 (100.0%) method 1 month 175800 (236.0%) 200800 (269.5%) 154300 (207.1%) 146000 (196.0%) (Test example 54) 2 months 253800 (340.7%) 302500 (406.0%) 186500 (250.3%) 176300 (236.6%)

(135) As shown in Table 10, the viscosity of the cream prepared by the conventional method increased significantly, when stored at any temperature of 0 to 50 C., about 2.0 to 2.7 times after 1 month and about 2.4 to 4.1 times after 2 months. On the other hand, the viscosity of the cream prepared by the method of the present invention hardly increased under any temperature of 0 to 50 C. Even in the highest case, the increase was only 3.2% (stored at 25 C. for 2 months). This high viscosity stability is not conceivable from the past common sense for -gel-containing O/W-type emulsion cosmetics.

(136) Thus, its cause was investigated. When the viscosity immediately after the production was compared, the cream prepared by the method of the present invention, regardless of the identical formulation, had about 3.4 times viscosity of the cream prepared by the conventional method. Accordingly, if prepared by the method of the present invention, the formation reaction of -gel is almost completed at the time of emulsion production, and the new formation reaction of -gel may not take place later (therefore, the viscosity does not increase).

(137) Furthermore, it was clarified that if the emulsion is prepared by the method of the present invention, an emulsion having very small particle sizes is obtained. Micrographs taken immediately after the production of the above-described -gel-containing O/W emulsion cosmetics prepared by the production method of the present invention (Test Example 53) and by the conventional production method (Test Example 54) are shown in FIG. 5 (top and bottom two micrographs on the left column). The average emulsion particle size of the cosmetic obtained by the production method of the present invention was about 500 nm; on the other hand, that of the cosmetic prepared by the conventional production method was about 3 m.

(138) The micrograph shown on the right column of the conventional method is an example where aggregated masses were generated because the cooling rate after emulsification was too fast in the conventional method (though the formulations are identical). Thus, it has been difficult to satisfactorily control the quality of products by the conventional production method of -gel-containing O/W emulsion cosmetics.

(139) Thus, it was shown that, a low-viscosity liquid consisting of a bicontinuous microemulsion phase or a dispersed liquid crystal phase (namely, the -gel intermediate composition of the present invention) obtained by mixing, with heating at 65 to 85 C., (A) a mixture of a higher alcohol having 16 or more carbon atoms and an anionic surfactant (mole ratio: 3:2 to 5:1) and (B) a mixture of a water-soluble solvent with the IOB value of 1.5 to 3.5 and water (mass ratio: 5:5 to 8:2) is an intermediate composition to easily and stably prepare an -gel-containing O/W emulsion cosmetic excellent in emulsion stability and viscosity stability. The method for use is a very simple in that the intermediate composition is heated to 65 to 85 C., oil heated to 85 C. or lower is added while stirring, and it is subsequently diluted, about 3 to 50 times by mass, by gradually adding water at 30 C. or lower. Although the method is exceedingly simple compared with the conventional method, the emulsion stability of the -gel-containing O/W emulsion cosmetic prepared by the present method is very high. In addition, it has unprecedented merits in that the viscosity increase over time is hardly observed.

Industrial Applicability

(140) The -gel intermediate composition of the present invention enables the preparation of an -gel-containing O/W emulsion cosmetic excellent in emulsion stability and viscosity stability by only adding heated oil to the heated composition and then diluting with water at room temperature. In addition, the intermediate composition can be stably stored, as a waxy solid, at room temperature over a long period. Therefore, industrial application values, such as the cost reduction by bulk preparation and the commercialization as an intermediate composition, are very high.

(141) Hereinafter, examples of the water-in-oil emulsion cosmetic of the present invention will be illustrated. It is to be understood that the present invention is not limited by these examples.

Example 8: Milky Lotion

(142) TABLE-US-00014 Components Blending quantity (mass %) (1) Sodium N-stearoyl methyl taurine 0.4 (2) Behenyl alcohol 1.1 (3) Stearyl alcohol 0.3 (4) Dipropylene glycol 5.0 (5) Ion-exchanged water 3.0 (6) Perfumes 0.1 (7) Pentaerythritol tetra-2-ethylhexanoate 2.0 (8) -olefin oligomer 3.0 (9) Dimethylpolysiloxane 2.0 (KF-96A-6cs, manufactured by Shin-Etsu Chemical Co., Ltd.) (10) Purified vaseline 1.0 (11) 1,3-Butylene glycol 2.0 (12) Phenoxyethanol 0.5 (13) Glycerin 4.0 (14) Carboxyvinylpolymer 0.03 (15) Potassium hydroxide 0.01 (16) Tranexamic acid 0.1 (17) Citric acid 0.02 (18) Sodium citrate 0.08 (19) Ion-exchanged water balance
(Preparation Method)

(143) A bicontinuous microemulsion was obtained by mixing with stirring components (1) to (5) at 80 C., and then oil and oil components (6) to (10) dissolved in advance at 80 C. were gradually added while stirring with a homogenizer. To the mixture, water and aqueous components (11) to (19) premixed at room temperature were slowly poured while stirring, and a milky lotion was obtained. The obtained milky lotion had extremely good viscosity stability compared with the milky lotion prepared by the conventional method (after emulsification by adding oil and oil components (=(2), (3), and (6) to (10)) dissolved by heating at 70 C. to water and aqueous components (=(1), (4), (5), and (11) to (19)) dissolved by heating at 70 C., cooling to 25 C. was carried out with an Onlator (Sakura Seisakusho Ltd.)).

Example 9: Milky Lotion

(144) TABLE-US-00015 Components Blending quantity (mass %) (1) Sodium N-stearoyl methyl taurine 0.6 (2) Behenyl alcohol 1.3 (3) 1,3-Butylene glycol 6.0 (4) Ion-exchanged water 2.0 (5) Perfumes 0.05 (6) Dimethylpolysiloxane 2.0 (KF-96A-6cs, manufactured by Shin-Etsu Chemical Co., Ltd.) (7) Squalane 4.0 (8) Cetyl isostearate 0.6 (9) Glycerin 5.0 (10) Carboxyvinylpolymer 1.0 (11) Potassium hydroxide 0.3 (12) Chamomile extract 0.1 (13) Ion-exchanged water balance
(Preparation Method)

(145) A lamellar liquid crystal dispersion was obtained by mixing with stirring components (1) to (4) at 85 C., and then oil and oil components (5) to (8) dissolved in advance by heating at 80 C. were gradually added while stirring with a homogenizer. To the mixture, water and aqueous components (9) to (13) premixed at room temperature were slowly poured while stirring, and a milky lotion was obtained. The obtained milky lotion had extremely good viscosity stability compared with the milky lotion prepared by the conventional method (after emulsification by adding oil and oil components (=(2) and (5) to (8)) dissolved by heating at 70 C. to water and aqueous components (=(1), (3), (4), and (9) to (13)) dissolved by heating at 70 C., cooling to 25 C. was carried out with an Onlator).

Example 10: Milky Lotion

(146) TABLE-US-00016 Components Blending quantity (mass %) (1) Sodium monostearyl phosphate 0.8 (2) Stearyl alcohol 1.5 (3) Isoprene glycol 4.5 (4) 1,4-butanediol 1.5 (5) Ion-exchanged water 1.5 (6) Perfumes 0.09 (7) Glyceryl tristearate 2.5 (8) Squalane 4.5 (9) Dimethylpolysiloxane 2.0 (KF-96A-6cs, manufactured by Shin-Etsu Chemical Co., Ltd.) (10) Dipropylene glycol 7.0 (11) Erythritol 1.3 (12) Glycerin 4.0 (13) Phenoxyethanol 0.3 (14) Xanthan gum 0.5 (15) Sodium hexametaphosphate 0.03 (16) Ion-exchanged water balance
(Preparation Method)

(147) A bicontinuous microemulsion was obtained by mixing with stirring components (1) to (5) at 80 C., and then oil and oil components (6) to (9) mixed in advance at 50 C. were gradually added while stirring with a homogenizer. To the mixture, water and aqueous components (10) to (16) premixed at room temperature were slowly poured while stirring, and a milky lotion was obtained. The obtained milky lotion had extremely good viscosity stability compared with the milky lotion prepared by the conventional method (after emulsification by adding oil and oil components (=(2) and (6) to (10)) dissolved by heating at 70 C. to water and aqueous components (=(1), (3) to (5), and (10) to (16)) dissolved by heating at 70 C., cooling to 25 C. was carried out with an Onlator).

Example 11: Sunscreen Cream

(148) TABLE-US-00017 Components Blending quantity (mass %) (1) Sodium N-stearoyl methyl taurine 1.2 (2) Behenyl alcohol 3.3 (3) Stearyl alcohol 0.9 (4) Dipropylene glycol 6.0 (5) Ion-exchanged water 2.0 (6) Perfume 0.08 (7) Glyceryl tri-2-ethylhexanoate 2.0 (8) Bis(2-ethylhexyl) succinate 3.0 (9) 2-Ethylhexyl p-methoxycinnamate 5.0 (10) Avobenzone 3.0 (11) Bis-ethylhexyloxyphenol 1.0 methoxyphenyl triazine (12) 1,3-Butylene glycol 5.0 (13) Phenoxyethanol 0.5 (14) Glycerin 9.0 (15) EDTA trisodium salt 0.1 (16) Erythritol 0.1 (17) Citric acid 0.02 (18) Sodium citrate 0.08 (19) Ion-exchanged water balance
(Preparation Method)

(149) A bicontinuous microemulsion was obtained by mixing with stirring components (1) to (5) at 80 C., and then oil and oil components (6) to (11) mixed in advance at 70 C. were gradually added while stirring with a homogenizer. To the mixture, water and aqueous components (12) to (19) premixed at room temperature were slowly poured while stirring, and a sunscreen cream was obtained. The obtained sunscreen cream had extremely good viscosity stability compared with the sunscreen cream prepared by the conventional method (after emulsification by adding oil and oil components (=(2), (3), and (6) to (11)) dissolved by heating at 70 C. to water and aqueous components (=(1), (4), (5), and (12) to (19)) dissolved by heating at 70 C., cooling to 25 C. was carried out with an Onlator).

Example 12: Cream

(150) TABLE-US-00018 Components Blending quantity (mass %) (1) Sodium N-stearoyl methyl taurine 1.3 (2) Behenyl alcohol 2.0 (3) 1,3-Butylene glycol 6.5 (4) Ion-exchanged water 1.5 (5) Perfumes 0.05 (6) Dimethylpolysiloxane 7.4 (KF-96A-6cs, manufactured by Shin-Etsu Chemical Co., Ltd.) (7) Squalane 4.0 (8) Behenyl alcohol 0.6 (9) Purified vaseline 1.0 (10) Dipropylene glycol 5.0 (11) Phenoxyethanol 0.5 (12) Glycerin 7.0 (13) EDTA3Na 0.1 (14) Chamomile extract 0.1 (15) Citric acid 0.02 (16) Sodium citrate 0.08 (17) Ion-exchanged water balance
(Preparation Method)

(151) A lamellar liquid crystal dispersion was obtained by mixing with stirring components (1) to (4) at 80 C., and then oil and oil components (5) to (9) mixed in advance at 80 C. were gradually added while stirring with a homogenizer. To the mixture, water and aqueous components (10) to (17) premixed at room temperature were slowly poured while stirring, and a cream was obtained. The obtained cream had extremely good viscosity stability compared with the cream prepared by the conventional method (after emulsification by adding oil and oil components (=(2) and (5) to (9)) dissolved by heating at 70 C. to water and aqueous components (=(1), (3), (4), and (10) to (17)) dissolved by heating at 70 C., cooling to 25 C. was carried out with an Onlator).