CN113811283A

CN113811283A - Liquid oil-in-water compositions

Info

Publication number: CN113811283A
Application number: CN202080036679.3A
Authority: CN
Inventors: 阿部茜; H·早濑
Original assignee: Kose Corp
Current assignee: Kose Corp
Priority date: 2019-05-17
Filing date: 2020-05-15
Publication date: 2021-12-17
Also published as: JPWO2020235459A1; WO2020235459A1; TW202110419A; KR20220009958A

Abstract

The invention aims to provide an oil-in-water emulsion composition which is liquid but has excellent viscosity stability and emulsion stability over time. The liquid oil-in-water composition of the present invention for solving the problem is characterized by containing the following components (a) to (C): (A) a linear saturated higher alcohol having 16 or more carbon atoms, (B) 1 or more anionic surfactants selected from sodium N-stearoyl-N-methyltaurate, N-stearoyl-L-glutamic acid and salts thereof, and (C) a liquid oil; and the content molar ratio (A/B) of the component (A) to the component (B) is 2.8-6, the content mass ratio ((A + B)/C) of the total of the components (A) and (B) to the component (C) is 0.3-0.75, wherein the average emulsified particle size is 160nm or less.

Description

Liquid oil-in-water compositions

Technical Field

The present invention relates to a liquid oil-in-water composition, and more particularly, to a liquid oil-in-water composition which is liquid but has excellent viscosity stability and emulsion stability with time.

Background

Conventionally, in an oil-in-water type composition, if the content of an oil agent is increased, there is a problem that emulsion stability such as separation or creaming (creaming) is lowered with time. In contrast, there have been tried a technique of blending a hydrophilic anionic surfactant and a higher aliphatic alcohol at a predetermined molar ratio to form an α -gel having a gel transition temperature of 60 ℃ or higher (patent document 1), a technique of preparing an α -gel intermediate composition in a bicontinuous microemulsion phase, the α -gel intermediate composition being composed of a mixture of a higher alcohol and an anionic surfactant at a predetermined molar ratio and a mixture of a water-soluble solvent having a predetermined IOB value and water at a predetermined mass ratio, adding heated oil to the composition, adding water and stirring the mixture, thereby inducing α -gel formation, and the like (patent document 2), and the improvement of emulsion stability is achieved by using the α -gel.

The alpha gel is one of self-organized bodies formed by amphiphilic substances, is positioned between solid hydrated crystals (coacervate) and lamellar liquid crystals, and is in a state of keeping a large amount of water between hydrophilic groups of the alpha gel while keeping a crystalline state. The crystals such as coacervated gel which hardly retain water are in a state in which the molecules themselves are inclined and are more densely packed, whereas the structure of the bilayer membrane of the lamellar liquid crystal is rich in fluidity and is in a liquid state, and therefore a large amount of water can be retained. In the α gel, the surfactant is arranged in a lamellar state in the same manner as in the lamellar liquid crystal, but since it is regularly filled in hexagonal crystals, although the rotational motion is maintained, the mobility of the hydrophobic group is insufficient compared to the lamellar liquid crystal, and the motion of the molecules is controlled. When the difference in the mobility based on such a structure is observed by Differential Scanning Calorimetry (DSC) or the like, thermal transition as a gel-liquid crystal phase transition is observed.

However, since α -gel is an intermediate phase between lamellar liquid crystal and coacervate and is therefore generally unstable, the oil-in-water emulsion compositions containing α -gel obtained by the techniques of patent documents 1 and 2 may lack viscosity stability, such as an increase in viscosity over time. The techniques of patent documents 1 and 2 are techniques for providing emulsion stability based on the thickening action of α -gel, and have a high viscosity immediately after preparation, and therefore it is difficult to apply the techniques to liquid cosmetics such as toilet water.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2001-348325

Patent document 2: japanese patent laid-open publication No. 2016-14011

Non-patent document

Non-patent document 1: J. soc, cosmet. chem. Jpn. 30 (3) 310-320(1996),

non-patent document 2: food Biophytics, 9/2012, Vol 7, No. 3, p 227-,

non-patent document 3: J. soc, cosmet. chem. Jpn. 44 (2) 103-117 (2010).

Disclosure of Invention

Problems to be solved by the invention

The invention aims to provide an oil-in-water emulsion composition which is liquid but has excellent viscosity stability and emulsion stability over time.

Means for solving the problems

The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that by combining a specific anionic surfactant such as sodium N-stearoyl-N-methyltaurate, N-stearoyl-L-glutamic acid, or a salt thereof with a linear saturated higher alcohol in a predetermined amount and adjusting the particle size of the emulsified droplets formed to 160nm or less, the emulsified droplets can be maintained in a liquid state for a long period of time from the time of preparation without thickening over time, and a good emulsified state can be stably maintained without causing creaming or separation, and have completed the present invention.

That is, the present invention is a liquid oil-in-water composition containing the following components (a) to (C):

(A) a linear saturated higher alcohol having 16 or more carbon atoms,

(B) 1 or more anionic surfactants selected from the group consisting of sodium N-stearoyl-N-methyltaurate, N-stearoyl-L-glutamic acid and salts thereof,

(C) a liquid oil;

wherein the content molar ratio (A/B) of the component (A) to the component (B) is 2.8 to 6, the content mass ratio ((A + B)/C) of the total of the components (A) and (B) to the component (C) is 0.3 to 0.75,

wherein the average emulsified particle diameter is 160nm or less.

ADVANTAGEOUS EFFECTS OF INVENTION

The oil-in-water emulsion composition of the present invention is liquid, but has excellent viscosity stability and emulsion stability over time, can maintain the liquid state without thickening for a long time, and can stably maintain a good emulsion state without causing creaming or separation. In addition, when the oil-soluble active ingredient is contained in the composition, the stability with time can be improved, and the action and effect based on the active ingredient can be stably maintained.

Drawings

FIG. 1 is a graph showing the results of Differential Scanning Calorimetry (DSC) analysis of a composition having an average emulsified particle size of 80nm, 110nm, 170nm, and 1 μm in test example 1.

FIG. 2 is a graph showing the results of X-ray diffraction of a composition having an average emulsified particle size of 80nm to 110nm in test example 1.

FIG. 3 is an electron micrograph of a composition having an average emulsified particle diameter of 110nm in test example 1.

FIG. 4 is an electron micrograph of the liposome of reference example 1.

Detailed Description

Examples of the linear saturated higher alcohol having 16 or more carbon atoms as the component (a) include cetyl alcohol, cetearyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl alcohol, and ceryl alcohol, and 1 or 2 or more of these can be used. Among them, from the viewpoint of viscosity stability and emulsion stability, cetearyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol and the like are preferable, and cetearyl alcohol and stearyl alcohol are particularly preferable. The content of the component (a) in the oil-in-water composition of the present invention (hereinafter, may be simply referred to as "composition") is preferably 0.5 to 2% by mass (hereinafter, simply referred to as "%"), more preferably 1 to 1.7%, from the viewpoint of viscosity stability and emulsion stability.

The component (B) is N-stearoyl-N-methyltaurate, N-stearoyl-L-glutamic acid or salts thereof as an anionic surfactant, and examples of N-stearoyl-L-glutamate include sodium salt, potassium salt, magnesium salt and the like, and 1 or 2 or more of them can be used. Among them, sodium N-stearoyl-N-methyltaurate, N-stearoyl-L-glutamic acid, and disodium N-stearoyl-L-glutamic acid are preferable from the viewpoint of viscosity stability and emulsion stability. The content of the component (B) in the composition of the present invention is preferably 0.4 to 1%, more preferably 0.5 to 0.9%, from the viewpoint of viscosity stability and emulsion stability.

The liquid oil as component (C) is not particularly limited as long as it is liquid at room temperature (25 ℃), and examples thereof include hydrocarbons such as isododecane, isohexadecane, light isoparaffin, liquid paraffin (mineral oil), squalane, squalene, α -olefin oligomer, polybutene, liquid isoparaffin, heavy liquid isoparaffin, polyisobutylene, hydrogenated polyisobutylene, and rapeseed oil, avocado oil, almond oil, apricot kernel oil, perilla oil, orange oil, olive oil, kiwi seed oil, sesame oil, wheat germ oil, rice bran oil, safflower oil, sage oil, soybean oil, tea seed oil, corn oil, rapeseed oil, evening primrose oil, camellia oil, peach kernel oil (Persic oil), sunflower seed oil, peanut oil, rapeseed oil, grape seed oil, canola oil, rosemary oil, jojoba oil, macadamia nut oil, sesame seed oil, safflower oil, sage oil, safflower oil, soybean oil, almond oil, evening primrose oil, camellia oil, sesame oil, sunflower seed oil, grape seed oil, meadowfoam seed oil, rosemary oil, jojoba seed oil, macadamia oil, and the like, Animal and vegetable oils such as lavender oil, rose hip oil, mink oil, etc., glyceryl tri (2-ethylhexanoate), isotridecyl isononanoate, isononyl isononanoate, cetyl 2-ethylhexanoate, isopropyl myristate, isopropyl palmitate, 2-ethylhexyl palmitate, octyldodecyl myristate, glyceryl trioctoate, glyceryl tri (octanoate/decanoate), glyceryl diisostearate, glyceryl triisostearate, polyglyceryl decaisostearate (polyglyceryl decaisostearate-10), propylene glycol didecanoate, neopentyl glycol didecanoate, polyglyceryl triisostearate, diisostearyl malate, neopentyl glycol diethylhexanoate, pentaerythritol tetraisostearate, pentaerythritol tetrakis (2-ethylhexanoate), dipentaerythritol pentaisostearate, mink oil, etc, Dialkyl carbonate, diethoxydiol cyclohexane-1, 4-dicarboxylate, dimer dilinoleyl hydrogenated rosin condensate and other esters, oleic acid, isostearic acid and other fatty acids, oleyl alcohol, 2-octyldodecanol, 2-decyltetradecanol, isostearyl alcohol, 2-hexyldecanol and other higher alcohols, dimethylpolysiloxane (dimethicone), methylpolytrimethylsiloxane, methylphenylpolysiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tetramethyltetrahydrocyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, tetramethyltetrakis (trifluoropropyl) cyclotetrasiloxane, pentamethylpenta (trifluoropropyl) cyclopentasiloxane, polyether-modified methylpolysiloxane, oleyl-modified methylpolysiloxane, polyvinylpyrrolidone-modified methylpolysiloxane and other silicone oils, perfluoropolyethers, and other hydrogenated rosin condensates, and other hydrogenated rosin esters, and other silicone oils, Fluorine-based oils such as perfluorodecane and perfluorooctane, lanolin derivatives such as lanolin acetate, lanolin fatty acid isopropyl ester and lanolin alcohol, and liquid ultraviolet absorbers such as 2-ethylhexyl p-methoxycinnamate and ethylhexyl salicylate, and 1 or 2 or more of these may be used.

Among them, from the viewpoint of viscosity stability and emulsion stability, nonpolar oils are preferred, and examples thereof include hydrocarbons such as isododecane, isohexadecane, light isoparaffin, liquid paraffin (mineral oil), squalane, squalene, α -olefin oligomer, polybutene, liquid isoparaffin, heavy liquid isoparaffin, polyisobutylene, hydrogenated polyisobutylene, and the like, silicone oils such as dimethylpolysiloxane (dimethylsilicone oil), methylpolytrimethylsiloxane, methylphenylpolysiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tetramethyltetrahydrocyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, tetramethyltetrakis (trifluoropropyl) cyclotetrasiloxane, pentamethylpenta (trifluoropropyl) cyclopentasiloxane, polyether-modified methylpolysiloxane, oleyl-modified methylpolysiloxane, polyvinylpyrrolidone-modified methylpolysiloxane, and the like, 1 or 2 or more of them may be used. Liquid paraffin (mineral oil) and dimethylpolysiloxane (simethicone) are particularly suitable. The content of the component (C) in the composition of the present invention is preferably 1 to 10%, more preferably 1.5 to 6.5%, from the viewpoint of viscosity stability and emulsion stability. From the viewpoint of improving the oil-soluble active ingredient, viscosity, and emulsification stability, the content mass ratio of the polar oil to the nonpolar oil ((polar oil)/(nonpolar oil)) is preferably 0.5 or less, and more preferably 0.3 or less. The liquid oil as the component (C) does not contain an oil-soluble active ingredient as the component (D) described later.

The IOB (Inorganic-organic balance) of the polar oil used in the present invention is more preferably 0.05 to 0.8, and still more preferably 0.05 to 0.6, from the viewpoint of viscosity stability and emulsion stability. The IOB of the nonpolar oil used in the present invention is preferably less than 0.05, and more preferably 0.03 or less, from the viewpoint of viscosity stability and emulsion stability.

Here, IOB in the present invention is a value calculated by (equation 1) below:

IOB = (Σ inorganic value/Σ organic) … (formula 1)

That is, the IOB may be calculated by: the "inorganic value" and the "organic value" of the atom and the functional group constituting the organic compound such as a surfactant are integrated based on the "inorganic value" and the "organic value" set for each atom and each functional group (see "organic concept diagram-base and application-" on pages 11 to 17, published in co-publication, published in 1984).

From the viewpoint of viscosity stability and emulsion stability, the IOB of the liquid oil mixture is preferably 0.8 or less, more preferably 0.6 or less, still more preferably 0.4 or less, and particularly preferably 0.2 or less.

Here, a mixed IOB (IOB) of N liquid oils_{General assembly}) Calculated using the following (equation 2):

IBO_{general assembly}=IOB₁·W₁+IOB₂·W₂+……IOB_N·W_N… (formula 2)

IOB₁、IOB₂、IOB_N: IOB of respective liquid oils

W₁、W₂、W_N: weight fraction (W) of each liquid oil₁+W₂+……+W_N=1)。

In the oil-in-water emulsion composition of the present invention, the content molar ratio (a/B) of the component (a) to the component (B) is preferably 2.8 to 6, and more preferably 2.8 to 4, from the viewpoint of viscosity stability and emulsion stability.

From the viewpoint of viscosity stability and emulsion stability, the content mass ratio ((a + B)/C)) of the total of the components (a) and (B) to the component (C) is preferably 0.3 to 0.75, and more preferably 0.3 to 0.72.

From the viewpoint of viscosity stability and emulsion stability, the content of water in the composition of the present invention is preferably 70 to 85%, more preferably 75 to 80%.

In the composition of the present invention, an aqueous solvent may be used in addition to water. Examples of the aqueous solvent include lower alcohols such as ethanol and propanol, glycols such as propylene glycol, 1, 3-butanediol, dipropylene glycol, 1, 2-pentanediol and polyethylene glycol, glycerols such as glycerol, diglycerol and polyglycerin, and 1 or 2 or more of them can be used. Among them, 1, 3-butanediol, dipropylene glycol, glycerin, diglycerin, and polyglycerin are preferable from the viewpoint of viscosity stability and emulsion stability. When an aqueous solvent is used, the content mass ratio of the aqueous solvent to water (water/aqueous solvent) is preferably 5 to 20, more preferably 6 to 15, from the viewpoint of viscosity stability and emulsion stability.

The composition of the present invention may further contain an oil-soluble active ingredient as the component (D). Examples of the oil-soluble active ingredient include tocopherol, carotenoid, retinol, ceramide, glycyrrhetinic acid, and esters thereof, oil-soluble licorice, oil-soluble coix seed extract, oil-soluble rosemary extract, ubidecarenone, and the like, and 1 or 2 or more of them can be used. The component (D) is preferably 1 or 2 or more selected from carotenoids and esters thereof. Examples of carotenoids include luteinizing pigment (actinoerythrol), astaxanthin, annatto, canthaxanthin, capsaicine, capsorubin, β -8 '-apo-carotenal (apocarotenal), β -12' -apo-carotenal, α -carotene, β -carotene, "carotenes" (a mixture of α -and β -carotenes), γ -carotene, δ -carotene, β -cryptoxanthin, echinenone, palm oil carotene, rutin, lycopene, violerythrin, zeaxanthin, fucoxanthin, antherin, violaxanthin, and the like, and esters of carotenoids, examples thereof include esters in which a substance having a hydroxyl group or a carboxyl group in a carotenoid forms 1 or more ester bonds with a fatty acid or a fatty alcohol. In particular, as the component (D), 1 or 2 or more species selected from astaxanthin and esters thereof are preferable. The ester-forming fatty acid or fatty alcohol preferably has a saturated or unsaturated, linear or branched hydrocarbon chain having 8 to 24 carbon atoms. The content of the component (D) in the composition of the present invention can be appropriately set according to the kind of the oil-soluble active ingredient, and is, for example, preferably 0.00001 to 1%, and more preferably 0.00001 to 0.5.

In the composition of the present invention, in addition to the above-mentioned components, any component may be used as necessary within a range not impairing the effects of the present invention. Examples of the optional component include solid oil, powder, an ultraviolet scattering agent, a preservative, and a perfume.

The composition of the present invention can be prepared by emulsifying and mixing the above-mentioned essential components and optional components to be blended as needed according to a known method. For example, the oil-in-water composition of the present invention can be prepared by dissolving an oil phase containing the components (a) to (C) and an aqueous phase containing water by heating, adding the oil phase to the aqueous phase, emulsifying and mixing the resulting mixture by dispersion or the like, and then subjecting the mixture to high-pressure emulsification treatment using a microfluidizer, Ultimaizer, NanoVater or the like.

From the viewpoint of viscosity stability and emulsion stability, the average emulsion particle size of the oil-in-water composition of the present invention is 160nm or less, preferably 60 to 130nm, and more preferably 70 to 120 nm. The average emulsified particle size can be adjusted by the pressure of the high-pressure emulsification treatment, the treatment time, the number of treatments, and the like. In the present specification, the average emulsified particle size is a value measured by the method described in examples.

The reason why the oil-in-water composition of the present invention has an average emulsified particle size of 160nm or less and is a composition which is liquid but has excellent viscosity stability with time is considered as follows. That is, in the production process of the oil-in-water composition of the present invention, when the α gel is formed from the components (a) and (B), if the particle diameter of the emulsified droplets is large, a part of the α gel exists around the emulsified droplets to coat the emulsified droplets, but the other α gel exists in a state of being dispersed in the continuous phase. It is considered that such remaining α gel forms a network of gel with time to cause an increase in viscosity. On the other hand, when the particle size of the emulsified droplets is made smaller, the proportion of α gel existing around the emulsified droplets becomes higher, and when the average emulsified particle size is in the range of 160nm or less, most of α gel covers the emulsified droplets, and the remaining α gel does not exist, so that the viscosity does not increase with time. When an anionic surfactant or a cationic surfactant other than the component (B) is used, even if the average emulsified particle size is 160nm or less, an α -gel film structure covering the emulsified droplets is not formed, and therefore, the viscosity increases with time.

As described above, in the oil-in-water composition of the present invention, it is preferable that all or a part of the emulsion droplets is coated with the α gel. The presence or absence of such an α gel film structure (hereinafter sometimes referred to as "α gel film structure") covering the emulsion droplets can be confirmed by Differential Scanning Calorimetry (DSC) measurement. That is, when the emulsion droplets were large (for example, the average emulsion particle size was about 1 μm), the DSC measurement was 581 endothermic peak based on the remaining alpha gel can be observed in the range of C to 68 ℃, but as the particle size of the emulsified droplets becomes smaller, another endothermic peak based on the alpha gel film structure of the coated emulsified droplets can be observed at a lower temperature side while the endothermic peak is gradually reduced. In this way, in the DSC measurement, when 2 endothermic peaks based on the residual α gel and α gel film structures, respectively, or only 1 endothermic peak based on the α gel film structure on the lower temperature side is observed in the range of 58 to 68 ℃, it is considered that there is an α gel film structure covering the emulsion droplets. In addition, the presence of the alpha gel film structure coating the emulsion droplets can also be determined by X-ray diffraction at 15nm^-1A peak was observed in the vicinity to confirm. That is, when the interplanar spacing of α gel is about 4.15 Å, the formula of q =2 × pi (circumferential ratio)/d (interplanar spacing) is satisfied between the interplanar spacing and the wave number q, and therefore the wave number is 15nm^-1(see non-patent documents 1 and 2 and FIG. 2). The presence of the α gel film structure covering the emulsion droplets can also be confirmed by electron microscope observation (see fig. 3).

The presence of such an α gel film structure covering the emulsion droplets is considered to contribute to the improvement in the stability of the oil-soluble active ingredient. That is, when the oil-in-water type emulsion composition contains the oil-soluble active ingredient, the oil-soluble active ingredient is mainly present in the emulsion droplets, but does not always stay at the same position, and molecular diffusion to the continuous phase, that is, the aqueous phase occurs (Ostwald ripping, see non-patent document 3), and the oil-soluble active ingredient is deteriorated by contact with water or the like in the continuous phase. In contrast, in the present invention, it is presumed that the presence of the α gel film structure covering the emulsion droplets makes the emulsion droplet interface stronger, and therefore contact with water or the like, which is accompanied by the austenite ripening of the oil-soluble active ingredient, can be suppressed, thereby improving the stability of the oil-soluble active ingredient over time.

As described above, in the DSC measurement, either or both of the endothermic peak based on the remaining α gel on the higher temperature side (60 ℃ or higher and 68 ℃ or lower) and the endothermic peak based on the α gel film structure of the coated emulsified droplets on the lower temperature side (58 ℃ or higher and lower than 60 ℃) can be contained in the range of 58 ℃ to 68 ℃. If it is to be passed 58The heat quantity (J/g) obtained by the area of all endothermic peaks included in the temperature range of from 68 ℃ is Q DEG C₀The quantity of heat obtained from the area of the endothermic peak based on the remaining alpha gel was measured as Q₁The quantity of heat obtained based on the area of the endothermic peak of the α gel film structure covering the emulsion droplet was measured as Q₂From the viewpoint of viscosity stability, the ratio Q of the quantity of heat obtained from the area of the endothermic peak of the remaining α gel to the quantity of heat obtained from the area of all the endothermic peaks₁/Q₀Preferably 0.7 or less, more preferably 0.2 or less, and still more preferably 0.1 or less. Heat quantity Q obtained from area of endothermic peak₀、Q₁、Q₂The results were obtained as follows. That is, a DDSC curve is created as a differential value of the obtained DSC curve, and a temperature at which the DDSC curve starts to incline is used as a base point. For the DSC curve, the peak area can be determined by connecting the base point to the base point (base line). If the area (cm) of all endothermic peaks contained in the temperature range of 58 ℃ to 68 ℃ is defined²) Is counted as A₀Will be based on the area of the endothermic peak (cm) of the remaining alpha gel²) Is counted as A₁Area of endothermic peak (cm) of alpha gel film structure based on coated emulsion droplet²) Is counted as A₂Then heat quantity Q₀、Q₁、Q₂Can be represented by the following formula:

here, m_iThe sample amount (g) is denoted by c as the feed rate (cm/s) of the recorded data, and P is a value (J/cm. multidot.s) corresponding to several joules in 1 second at 1cm on the ordinate of the DSC curve.

The thickness of the α gel film in the α gel film structure is preferably 5 to 20nm, and more preferably 5 to 10nm, from the viewpoint of viscosity stability and emulsion stability. In the present specification, the film thickness of the α gel film refers to an average value of the film thicknesses of the α gel films of 100 emulsion droplets measured by electron microscope observation.

The oil-in-water emulsion composition of the present invention is useful as cosmetics, quasi drugs, etc., and is in the form of a liquid such as a cosmetic preparation including a cosmetic water, a cosmetic liquid, a spray base liquid, a hair protectant, a liquid foundation, etc. In the present specification, the term "liquid" means a liquid having a viscosity of 100 mPas or less, preferably 50 to 0 mPas, as measured by the method described in examples.

Examples

The present invention will be described in more detail with reference to examples and the like, but the present invention is not limited to these examples and the like.

Test example 1: structural change and stability due to particle size of emulsified droplets

An oil-in-water composition having an average emulsified particle size of 80nm, 110nm, 170nm or 1 μm was prepared by the following formulation and preparation method. The obtained compositions were subjected to DSC measurement under the following conditions. In addition, X-ray diffraction was performed on a composition having an average emulsified particle size of 80nm to 110nm by the following method. Further, the composition having an average emulsified particle size of 110nm was observed by an electron microscope by the following method. The results are shown in FIGS. 1-3.

(formulation)

(ingredient) (%)

1. Dimethylsilicone oil (6 mPa. multidot.s at 25 ℃) 5.0

2. Cetyl alcohol 1.5

3. Sodium N-stearoyl-N-methyltaurate 1.0

4.1, 3-butanediol 12.0

5. Nipagin methyl ester 0.15

6. 0.15 parts of phenoxyethanol

7. Purified water 80.2.

(preparation method)

A: uniformly heating, mixing and dissolving the serial numbers 1-3

B: heating, mixing and dissolving the serial numbers 4-7 uniformly

C: adding A into B, emulsifying, mixing, and cooling

D-1: c was subjected to high-pressure dispersion treatment 2 times (pressure: 130MPa) using a microfluidizer to prepare an oil-in-water emulsion composition having an average emulsion particle diameter of 80nm

D-2: c was subjected to high-pressure dispersion treatment 3 times (pressure: 100MPa) using a microfluidizer to prepare an oil-in-water emulsion composition having an average emulsion particle diameter of 110nm

D-3: c was subjected to high-pressure dispersion treatment 2 times (pressure 80MPa) using a microfluidizer to prepare an oil-in-water emulsion composition having an average emulsion particle diameter of 170nm

D-4: the mixture C was stirred at 2000rpm by a disperser to prepare an oil-in-water emulsion composition having an average emulsion particle size of 1 μm.

(method of measuring average emulsion particle size)

Dynamic scattering method based on measurement principle

Solvent water

The measurement temperature is 20 DEG C

Real-time nanometer particle size measuring device DelsaMax CORE of measuring device

Light source 100 mW DPSS single longitudinal mode laser

Laser wavelength 658 nm

Detector particle size determination Avalanche Photodiode (APD)

Angular particle diameter measurement by detector at 90 °

The particle size calculation method calculates an autocorrelation coefficient by a Multi-channel time delay (Multi-tau) method, and calculates the particle size.

(DSC measurement method)

The use equipment comprises the following steps: EXSTAR DSC6200 (manufactured by Seiko Instruments Inc.)

Reference: AIR

Temperature rise rate: the concentration of the active carbon is 5Cel/min,

disc: P/N SSC000E031 AL15-CAPSULE

Analysis software: EXSTAR6000 thermal analysis/rheology system (Seiko Instruments Inc.).

(X-ray diffraction method)

Measurement equipment: SAXSess (manufactured by AntonPaar corporation)

The measurement conditions were as follows: at 25 deg.C for 20 min.

As shown in FIG. 1, in the composition having an average emulsified particle size of 1 μm, an endothermic peak due to the remaining α gel was found at around 61 ℃. The peak is reduced as the particle size of the emulsion droplet is reducedHowever, in the composition having an average emulsified particle diameter of 110nm, a peak based on the α gel film structure of the coated emulsified droplets was found at around 58 ℃. In the composition having an average emulsified particle diameter of 80nm, the peak at around 61 ℃ disappeared, and the peak at around 58 ℃ was observed. This suggests that the α gel is mainly dispersed in the continuous phase as the remaining α gel when the average emulsified particle size is 1 μm to 170nm, but the α gel covering the emulsified droplets and the remaining α gel coexist when the average emulsified particle size is 110nm, and the α gel is mainly present as a substance covering the emulsified droplets when the average emulsified particle size is 80 nm. In the composition with average emulsified particle size of 110nm and 80nm, the alpha gel film structure for forming the coated emulsified droplets can also be obtained by X-ray diffraction at 15nm^-1The presence of peaks (FIG. 2) and electron micrographs (FIG. 3) were confirmed.

Based on FIG. 1, the heat quantity Q determined from the areas of all endothermic peaks was determined using the above-mentioned analysis software EXSTAR6000₀And a heat quantity Q obtained from the area of the endothermic peak of the remaining alpha gel₁And a heat quantity Q obtained from an area of an endothermic peak of an alpha gel film structure based on the coated emulsion droplet₂Calculating the ratio Q of the quantity of heat obtained from the areas of the endothermic peaks based on the remaining alpha gel to the quantity of heat obtained from the areas of all the endothermic peaks₁/Q₀. The results are shown in table 1.

[ Table 1]

Average emulsified particle size	Q₀	Q₁	Q₂	Q₁/Q₀
					80nm	1.91	0	1.91	0
110nm	1.10	0.15	0.33	0.136
					170nm	1.20	0.94	0.04	0.783
1μm	1.82	1.82	0	1

For each composition, the viscosity and emulsified state immediately after preparation and after storage at 50 ℃ for 1 month were evaluated according to the following measurement methods and judgment standards. The results are shown in table 2.

(method of measuring/evaluating Property (viscosity))

Immediately after the preparation and after 1 month of storage at 50 ℃, the viscosity of each sample at 25 ℃ was measured and evaluated according to the following criteria. The viscosity was measured according to the standard of cosmetic raw materials viscosity measurement method second method using Brookfield type viscometer:

(judgment): (measurement results)

Very good: 10 mPa.s or less

Good: more than 10 mPas and less than 100 mPas

X: over 100 mPas.

(method of evaluating Properties (emulsified State))

The emulsified state of each sample immediately after preparation and after 1 month storage at 50 ℃ was visually confirmed and evaluated according to the following criteria:

(judgment): (State)

Good: no creaming and separation was observed

And (delta): although no separation was found, creaming was found

X: separation was found.

[ Table 2]

As can be seen from tables 1 and 2, the ratio Q to the average emulsified particle diameter was 170nm₁/Q₀In the test example of 0.783, the average emulsified particle diameter was 110nm and the ratio Q was₁/Q₀Test example 0.136 and average emulsified particle diameter 80nm, ratio Q₁/Q₀The test example 0 did not increase in viscosity even after being stored at 50 ℃ for 1 month, maintained a viscosity of 100 mPas or less, and was excellent in viscosity stability with time.

Reference example 1: preparation of a cosmetic liquid containing liposomes

A cosmetic lotion having the following composition was prepared by the following preparation method. The obtained toner was observed with an electron microscope. The electron micrograph is shown in fig. 4.

Reference example 1: toning lotion

(ingredient) (%)

1. Phospholipid 1.0

2. Xanthan gum 0.1

3. Carboxyvinyl Polymer 0.05

4.1, 3-butanediol 20.0

5. Glycerol 4.5

6. Sodium hydroxide 0.02

7. Parabens 0.1

8. Trace amount of perfume

9. And (4) purifying the balance of water.

(preparation method)

A: lipidizing a portion of Nos. 1, 8 and 9

B: mixing the rest of the materials

C: mixing A and B to obtain cosmetic water.

The emulsified droplets with the alpha gel membrane structure of the present invention in fig. 3 have an oil phase inside, in contrast to which the liposomes in fig. 4 do not have an oil phase inside, which is clearly different. Further, although the liposome formed a multi-layered membrane, it was found that the membrane structure existed in a plurality of layers, the α -gel membrane structure of the present invention was found to have no layer-like membrane structure and the number of layer-like membranes was found to be small.

It is also found that the α gel film of the present invention is a linear saturated higher alcohol having 16 or more carbon atoms and having a thickness of about 3 molecular weight (the α gel film is a higher alcohol 3 molecular film). In addition to the formation of the α gel film structure, the formation of 5-molecule films, 7-molecule films, 9-molecule films, and the like can be considered, but in that case, a network structure may be formed due to an increase in the number of films, and the film may be thickened. Therefore, from the viewpoint of viscosity stability and emulsion stability, the thickness of the α gel film is preferably 5 to 20nm, more preferably 5 to 10nm, and still more preferably a linear saturated higher alcohol having about 3 molecular weight and having 16 or more carbon atoms (the α gel film is a higher alcohol 3 molecular film).

Examples 1 to 14 and comparative examples 1 to 12

Lotions having compositions shown in tables 3 to 6 were prepared by the following preparation methods. With respect to the obtained lotion, the viscosity and emulsified state immediately after the preparation and after 1 month at 50 ℃ storage were evaluated according to the following measurement methods and judgment standards. The presence of the α gel film structure covering the emulsion droplets was evaluated by the following method. The results are shown in tables 3 to 6. The numerical values in the compositions of tables 3 to 6 are% by weight.

[ Table 3]

1 Nikkol SMT (Nikko Chemicals Co., Ltd.)

2 Amisoft HA-P (Xiangrong Daoshi)

3 Nikkol DDP-8 (Nikko Chemicals co., ltd.).

[ Table 4]

[ Table 5]

[ Table 6]

< preparation method >

(examples 1, 7, 8 and 10)

A: uniformly heating, mixing and dissolving the serial numbers 1-15

B: uniformly heating, mixing and dissolving the serial numbers 16-19

C: adding A to B, and emulsifying and mixing

D: cooling C, and performing high-pressure dispersion treatment (pressure of 200MPa) for 2 times by using a micro-jet machine to obtain the lotion.

(examples 2, 11 to 14)

A: uniformly heating, mixing and dissolving the serial numbers 1-15

B: uniformly heating, mixing and dissolving the serial numbers 16-19

C: adding A to B, and emulsifying and mixing

D: cooling C, and performing high-pressure dispersion treatment (pressure of 200MPa) for 1 time by using a micro-jet machine to obtain the lotion.

(examples 3 to 6 and 9, comparative examples 1 to 12)

A: uniformly heating, mixing and dissolving the serial numbers 1-15

B: uniformly heating, mixing and dissolving the serial numbers 16-19

C: adding A to B, and emulsifying and mixing

D: cooling C, and performing high-pressure dispersion treatment (pressure of 100MPa) for 2 times by using a micro-jet machine to obtain the lotion.

< evaluation method >

(Presence of an alpha gel film Structure coating the emulsion droplets)

Each lotion was evaluated by observing an endothermic peak by DSC measurement under the following conditions according to the following criteria.

[ DSC conditions ]

Reference: AIR

Temperature rise rate: 5Cel/min

Disc: P/N SSC000E031 AL 15-CAPSULE.

[ determination standards ]

(judgment): (State)

Very good: only 1 peak was observed in the vicinity of 58 ℃

Good: 2 peaks were observed at around 58 ℃ and 61 ℃ respectively

And (delta): only 1 peak was observed in the vicinity of 61 ℃

X: no peak was observed

-: it could not be measured.

The samples judged as ∈ or good by the DSC measurement were observed by electron microscope observation to observe the condition of the emulsion droplets coated with the α -gel film structure (see fig. 3, the portion surrounded by a circle in the figure). X-ray diffraction was carried out (measurement apparatus: SAXSess (manufactured by Anton Paar Co., Ltd.)) at a measurement condition of 25 ℃ for 20min, and the result was 15nm^-1Peaks derived from the α gel film structure were found (see fig. 2).

(method of measuring/evaluating Property (viscosity))

Immediately after the preparation and after 1 month of storage at 50 ℃, the viscosity of each sample at 25 ℃ was measured and evaluated according to the following criteria. The viscosity was measured according to the standard of cosmetic raw materials/viscometry method second method using a brookfield type viscometer.

(judgment): (measurement results)

Very good: 10 mPa.s or less

Good: more than 10 mPas and less than 100 mPas

X: over 100 mPas.

(method of evaluating Properties (emulsified State))

The emulsified state of each sample immediately after preparation and after 1 month storage at 50 ℃ was visually confirmed, and evaluated according to the following criteria.

(judgment): (State)

Good: no creaming and separation was observed

And (delta): although no separation was found, creaming was found

X: separation was found.

As shown in tables 3 and 4, the lotions of examples 1 to 14 were found to have an α -gel film structure covering the emulsion droplets, to be in a liquid state from immediately after the preparation, and to maintain a viscosity of 100mPa · s or less without increasing the viscosity even after being stored at 50 ℃ for 1 month. In addition, no separation or creaming occurs, and a good emulsified state is maintained. On the other hand, with respect to the lotions of comparative examples 1 to 2 having an average emulsified particle size of 170nm or more, the presence of an α -gel film structure was not confirmed, and an increase in viscosity with time was observed. In addition, in place of the component (a), the straight-chain saturated higher alcohol having 16 or more carbon atoms, the lotions of comparative examples 3 to 5 using a branched substance or a substance having less than 16 carbon atoms were all separated (initial separation) from the lotion just after the preparation. The initial separation similarly occurred when a nonionic surfactant was used instead of the component (B) (comparative example 6), and when a cationic surfactant or an anionic surfactant other than the component (B) was used, the presence of an α -gel film structure was not confirmed, and even if the average emulsified particle size was set to 160nm or less, the emulsion stability and viscosity stability were poor, such as separation or increase in viscosity with time after 1 month storage at 50 ℃. In addition, when the content mass ratio of the component (C) to the total of the components (a) and (B) is out of the range of 0.3 to 0.75, the emulsion stability and the viscosity stability are similarly poor (comparative examples 7 to 10).

Test example 2: stability test of oil-soluble effective ingredient

Lotions having compositions shown in table 7 below were prepared by the following preparation methods. The stability of the oil-soluble active ingredient was evaluated for the obtained cosmetic liquid by the following method.

[ Table 7]

4 astaxanthin-5C (Oryza Oil & Fat Chemical Co., Ltd.)

'xing 5 beta' -carotene (Sanshu medicine)

6 Kaneka coenzyme Q10 (Kaneka).

(preparation method)

A: uniformly heating, mixing and dissolving the serial numbers 1-8

B: uniformly heating, mixing and dissolving the serial numbers 9-12

C: adding A to B, and emulsifying and mixing

D: cooling C, and performing high-pressure dispersion treatment (pressure of 130MPa) for 2 times by using a micro-jet machine to obtain the lotion.

(method for evaluating stability of astaxanthin,. beta. -carotene and ubidecarenone)

For each lotion, absorbance was measured immediately after preparation and after 1 month of storage at 50 ℃. Absorbance was measured using a SPECTROPHOTOMETER UV-2500PC UV-VIS REDC ORDING SPECTROPHOTOMETER (manufactured by SHIMADZU Co., Ltd.) using a glass cuvette having an optical path length of 10mm × an optical path width of 10mm, astaxanthin at a wavelength around 480nm, beta-carotene at a wavelength around 450nm, and ubidecarenone at a wavelength around 280nm using purified water as a reference. The residual rate of absorbance was calculated by the following formula, and the stability of astaxanthin, beta-carotene, ubidecarenone was evaluated according to the following criteria:

absorbance residual rate (%) = (absorbance of sample after 1 month storage at 50 ℃) x 100/(absorbance of sample immediately after preparation).

< stability determination Standard >

(judgment): (residual Rate of absorbance)

Very good: the residual rate of absorbance is 60% or more

Good: the residual rate of absorbance is 50-60%

X: the residual rate of absorbance was less than 50%.

As shown in Table 7, in the cosmetic liquid of example 15, the discoloration of astaxanthin after storage at 50 ℃ for 1 month was significantly suppressed as compared with that of comparative example 13. This is considered to be because the emulsion droplets are covered with the α gel film structure in example 15, and the emulsion droplet interface becomes stronger, and therefore contact with water or the like accompanying austenite ripening of astaxanthin is suppressed, and decomposition of astaxanthin and the like are suppressed, whereas the α gel film structure is not formed around the emulsion droplets in the cosmetic water of comparative example 13, and contact with water or the like and decomposition accompanying the same occur. Similarly, it was confirmed that beta-carotene and ubidecarenone were stably maintained even after storage at 50 ℃ for 1 month.

Test example 3: polar to non-polar oil ratio and stability

Lotions having compositions shown in table 8 below were prepared by the following preparation methods. The obtained lotions were evaluated for viscosity and emulsified state immediately after preparation and after 1 month of storage at 50 ℃ in the same manner as in examples 1 to 14. The stability of astaxanthin was evaluated in the same manner as in test example 2. The results are shown in Table 6.

[ Table 8]

*7 HICALL K-230 (Kaneda)

*8 Myritol GTEH (BASF)。

(preparation method)

A: heating, mixing and dissolving the serial numbers 1-5 uniformly

B: uniformly heating, mixing and dissolving serial numbers 6-9

C: adding A to B, and emulsifying and mixing

As shown in Table 8, the lotions of examples 19 to 21 and example 25 were superior to the lotion of example 27 in viscosity stability and emulsion stability after storage at 50 ℃ for 1 month. In addition, the lotions of examples 22 to 24 and 26 were superior to the lotion of example 28 in viscosity stability, emulsion stability and stability of oil-soluble active ingredients after storage at 50 ℃ for 1 month. This is considered to be because the lower the content mass ratio of the polar oil to the nonpolar oil ((polar oil)/(nonpolar oil)), the lower the compatibility with the linear saturated higher alcohol, and the better the high-temperature stability over time of the α -gel film structure.

Example 27: toning lotion

(ingredient) (%)

1. Dimethylsilicone oil (6 mPa. multidot.s at 25 ℃) 4.5

2. Ethyl hexyl palmitate^*9 0.5

3. Cetostearyl alcohol 1.5

4. Behenyl alcohol 0.8

5. Cetostearyl alcohol 0.8

6. Sodium N-stearoyl-N-methyltaurate 0.7

7. Glycerol 1.0

8.1, 3-butanediol 12.0

9. Tripropylene glycol 0.5

10. Citric acid 0.01

11. Citric acid Na 0.01

12. Purified water balance

9 SALACOS P-8 (manufactured by Nisshin Oillio Group).

(preparation method)

A: heating, mixing and dissolving the serial numbers 1-5 uniformly

B: uniformly heating, mixing and dissolving serial numbers 6-12

C: adding A to B, and emulsifying and mixing

The astringent of example 27 obtained as described above was in a liquid state of 30 mPas immediately after preparation, and had an average emulsified particle size of 80nm and a good emulsified state. The viscosity stability and emulsion stability were also good after 1 month at 50 ℃.

Industrial applicability

The oil-in-water emulsion composition of the present invention is liquid, but has excellent viscosity stability and emulsion stability over time, and therefore, can be used for liquid cosmetics, quasi drugs, and the like.

Claims

1. A liquid oil-in-water composition comprising the following components (A) to (C):

(A) a linear saturated higher alcohol having 16 or more carbon atoms,

(C) a liquid oil;

wherein the average emulsified particle diameter is 160nm or less.

2. The liquid oil-in-water composition according to claim 1, wherein the viscosity at 25 ℃ is 100 mPas or less.

3. The liquid oil-in-water composition according to claim 1 or 2, wherein the component (C) liquid oil is 1 or 2 selected from mineral oil and dimethicone.

4. The liquid oil-in-water composition according to any one of claims 1 to 3, wherein the content mass ratio of the polar oil to the nonpolar oil ((polar oil)/(nonpolar oil)) in the liquid oil as component (C) is 0.5 or less.

5. The liquid oil-in-water composition according to any one of claims 1 to 4, further comprising an oil-soluble active ingredient as the ingredient (D).

6. The liquid oil-in-water composition according to any one of claims 1 to 5, wherein a ratio of an amount of heat determined from an endothermic peak area based on the remaining alpha gel to an amount of heat determined from all endothermic peak areas contained in a temperature range of 58 to 68 ℃ in a DSC curve measured by a differential scanning calorimeter is 0.7 or less.