Oil-in-water emulsion composition

Abstract

The objective of the present invention was to develop an emulsified composition that provides skin care in response to the skin condition. [Solution] This oil-in-water emulsion aggregates in response to the skin's natural moisturizing factors. It contains a specific composition of non- to low-polarity oils, higher alcohols, fatty acids, and esters of fatty acids and glyceryl polymers, with primary particles adjusted to 1 μm or less, allowing Brownian motion to carry the emollient ingredients to the finest parts of the skin. If there are a lot of natural moisturizing factors, the emulsion aggregates and stops moving. On dry skin, the need to increase the amount used is apparent from the feel on the skin. Compared to creams of the same composition, it provides sustained moisturizing, reduces shine, and leaves skin with a translucent appearance.

Description

[Technical Field]

[0001] The present invention relates to an oil-in-water emulsion composition characterized by coagulating with the skin's natural moisturizing factors, the degree of coagulation varying depending on the moisturizing state of the skin, and excellent skin moisture retention. [Background technology]

[0002] Because oil replenishment is effective in maintaining healthy skin, many skin care products contain oil. Oil-in-water emulsions, which have a water phase as the continuous phase, are popular due to their pleasant texture. It is known that the presence of electrolytes in oil-in-water emulsions reduces the repulsive forces between oil particles, causing them to aggregate (e.g., Interface Science for Cosmetics, Quasi-drugs, and Pharmaceuticals, p. 23, Fragrance Journal, Inc., 2015). This process, which progresses through aggregation, coalescence, and separation into water and oil, has been considered a factor in reducing stability. Electrolytes used in skin care products include thickeners such as carboxyvinyl polymers, pH adjusters such as sodium citrate, ionic surfactants such as soap, minerals such as sea salt, and the main ingredient in quasi-drugs, dipotassium glycyrrhizinate. Herbal extracts and fermented extracts also contain many electrolytes, making them a versatile blend. When electrical conductivity was measured as an indicator of electrolyte concentration, a 0.1% aqueous solution of carboxyvinyl polymer was 56 μS / cm, a 0.01% aqueous solution of sodium citrate was 50 μS / cm, a 0.005% aqueous solution of sodium chloride was 82 μS / cm, and a 5% aqueous solution of POE(60) hydrogenated castor oil, a commonly used nonionic surfactant, was 50 μS / cm. The electrical conductivity of a total of 15 commercially available creams and serums was measured and ranged from 216 to 5494 μS / cm. Commercially available products are stable in the presence of electrolytes of this level, with no effect on their properties due to the decrease in repulsive forces between oil particles. The skin contains natural moisturizing factors, including sodium lactate, sodium PCA, and amino acids, many of which are electrolytes. Using the Ajinomoto Healthy Supply Co., Ltd. Produe pamphlet, Aikoku Gakuen Junior College Bulletin 36 (2018) p. 84, and Kastuyuki Maeno "Direct Quantification of Natural Moisturizing Factors in Stratum Corneum using Direct Analysis in Real Time Mass Spectrometry with Inkjet-Printing technique" SCIENTIFIC REPORTS 9:17789 (2019) as references, an aqueous solution (aqueous solution of simulated natural moisturizing factors) containing 78.93 wt% purified water, 13.54 wt% PCA-Na, 5.95 wt% sodium lactate, 0.51 wt%, 0.34 wt% glycine, 0.25 wt% glutamic acid, 0.14 wt%, 0.12 wt% alanine, 0.12 wt%, 0.12 wt% lysine, 0.07 wt%, and 0.03 wt% proline was prepared as a simulated natural moisturizing factor. 2 When electrical conductivity was measured as an indicator of electrolyte concentration, the electrical conductivity of a 0.1% by weight simulated natural moisturizing factor solution, which was a 1000-fold dilution of this simulated natural moisturizing factor solution, was 63 μS / cm. This is lower than the electrical conductivity of the commercially available product, and it can be inferred that an aggregation reaction does not occur with natural moisturizing factor.

[0003] One technology that is thought to involve aggregation reactions is an emulsion (Patent Document 1), which is characterized by becoming creamy when applied to the skin and stretched. 0.1 parts by weight of a 20% by weight aqueous solution of sodium citrate as an electrolyte was added to 1 part by weight of the emulsion, and the mixture was stirred with a spatula or similar for approximately 30 seconds until it became creamy. The concentration of sodium citrate was equivalent to 2% by weight, and the measured electrical conductivity of the 2% by weight aqueous solution of sodium citrate was 12,840 μS / cm. Furthermore, application and stretching caused the continuous phase to volatilize and shear stress to be applied, resulting in a uniform reaction regardless of the skin's natural moisturizing factors.

[0004] Similarly, there is a technology (Patent Document 2) in which a liquid or emulsion is applied to the skin and stretched to become a cream. This technology is limited to highly concentrated emulsions, and reacts uniformly regardless of the condition of the skin.

[0005] As a technology that responds to electrolytes in the skin, there is a topical skin preparation (Patent Document 3) that contains an electrolyte-responsive water-soluble polymer (meth)acrylic acid / (meth)acrylic acid alkyl ester copolymer. This topical skin preparation has an electrical conductivity of less than 400 mS / m at 25°C, and is characterized by its ability to thicken and adhere to the skin in response to electrolytes on the skin, as well as its excellent change in feel when used.

[0006] As a technology that responds to skin conditions, there is a body odor suppression technology (Patent Document 4) that uses carboxyl group-modified amylose to release fragrances, deodorants, antiperspirants, cooling agents, and disinfectants depending on the pH of the skin.

[0007] Technologies that respond to skin conditions include a technology that delivers drugs such as organic cosmetic active molecules through a collapse and swelling mechanism triggered by the temperature and pH response of skin by incorporating a cross-linked poly(ethylene glycol) methyl ether methacrylate polymer (Patent Document 5), a technology for microcapsules that respond to skin temperature by incorporating polyisopropylacrylamide (Patent Document 6), and a temperature-responsive functional face pack that incorporates a chitosan-modified hydrogel of isopropylacrylamide and polyurethane copolymer (Patent Document 7). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 6883312 [Patent Document 2] Japanese Patent Application Publication No. 9-151112 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-235008 [Patent Document 4] Patent No. 6445759 [Patent Document 5] Patent No. 7152110 [Patent Document 6] Patent No. 4734661 [Patent Document 7] Special Publication No. 2008-546723 Summary of the Invention [Problem to be solved by the invention]

[0009] Compositions that respond specifically to skin conditions (electrolytes, pH, temperature, etc.) require sensitive compounds, which can raise safety concerns about residual monomers in the polymer, and after the specific response, the compounds are often no longer needed by the skin. There has been no technology that responds to slight differences in skin conditions (electrolytes, pH, temperature, etc.) using emulsion components alone. The present invention has been developed in light of the above circumstances, and aims to provide a skin care formulation that uses an emulsion composition to aggregate in response to slight changes in skin conditions (electrolytes, pH, temperature, etc.), thereby maintaining skin moisture and leading to skin with a translucent appearance. [Means for solving the problem]

[0010] As a result of extensive research aimed at solving the above-mentioned problems, we have found that an oil-in-water emulsion composition containing a non- to low-polarity oil, a higher alcohol, a fatty acid, and an ester of a fatty acid and glyceryl, and an ester of a fatty acid and glyceryl polymer, aggregates in a sensitive response to even minute amounts of natural moisturizing factors present in the skin. By preparing the primary particles into fine particles, they can move through Brownian motion to reach the finer parts of the skin, and can also moisturize the surface by aggregation. If the amount of natural moisturizing factors is low, a large amount of this composition must be used to aggregate, but the appropriate amount can be determined by the feel of use, allowing for skin care.

[0011] The present invention provides an oil-in-water emulsion composition comprising (A) 0.1 to 10.0 mass% of one or more oils selected from oils having an organic conceptual diagram IOB value of 0.05 or less, (B) 0.1 to 1.2 mass% of one or more higher alcohols having 14 to 24 carbon atoms, (C) 0.1 to 1.0 mass% of one or more fatty acids having 12 to 24 carbon atoms, and (D) as an surfactant, one or more esters of fatty acids having 12 to 24 carbon atoms and glycerin, and one or more esters of fatty acids having 12 to 24 carbon atoms and glycerin polymers, and the primary particle size is 1 μm or less.

[0012] Furthermore, the oil-in-water emulsion composition contains collagen and / or hydrolyzed collagen.

[0013] Alternatively, the oil-in-water emulsion composition contains ceramide NP.

[0014] The present invention also provides the oil-in-water emulsion composition, which has an electrical conductivity of 100 μS / cm or less.

[0015] Provided is an oil-in-water emulsion composition characterized in that it aggregates when 0.1 parts by weight of a simulated natural moisturizing factor aqueous solution (a solution containing 78.93 wt% purified water, 13.54 wt% PCA-Na, 5.95 wt% sodium lactate, 0.51 wt% serine, 0.34 wt% glycine, 0.25 wt% glutamic acid, 0.14 wt% alanine, 0.12 wt% arginine, 0.12 wt% lysine, 0.07 wt% threonine, and 0.03 wt% proline) is added to 100 parts by weight of the oil-in-water emulsion composition. [Effects of the Invention]

[0016] When the skin is dry, due to factors such as low natural moisturizing factors or low sebum, the oil particles of the oil-in-water emulsion composition of the present invention reach every detail of the skin through Brownian motion, providing moisture. When the skin's natural moisturizing factors and sebum are present and the moisturizing function is sufficient, the oil-in-water emulsion composition of the present invention immediately aggregates, and the oil droplets coalesce through evaporation of the continuous phase, Ostwald ripening, and other processes, thereby conditioning the skin surface. This formulation's behavior changes depending on slight differences in skin condition. The oil-in-water emulsion composition of the present invention, which has a high oil concentration, feels like it is coagulating upon use. The oil-in-water emulsion composition of the present invention can control its tendency to aggregate depending on the user's skin condition. It can also be used as a supplementary item after using existing skin care products, depending on the skin condition. By adjusting these properties, it is possible to condition the skin according to the skin condition, maintain moisture for a long time, and achieve a translucent skin. [Brief explanation of the drawings]

[0017] [Figure 1] Number of times washing with face wash for 1 minute and particle size of oil-in-water emulsion composition placed on the skin [Figure 2] Changes in skin moisture over time [Figure 3] High viscosity type that does not drip easily during use. Changes in skin moisture over time. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will be specifically described, focusing on its preferred embodiments. Terms without a description of secondary particles refer to a primary particle dispersion system.

[0019] Examples of the component (A) of the present invention, oils having an organic conceptual diagram IOB value of 0.05 or less, include petrolatum, mineral oil, squalane, etc. The total amount of these is 0.1 to 10.0 mass %, more preferably 1.0 to 9.0 mass %.

[0020] The component (B) of the present invention, higher alcohols having 14 to 24 carbon atoms, include behenyl alcohol, hydrogenated rapeseed oil alcohol, cetostearyl alcohol, cetanol, etc. The total amount of these is 0.1 to 1.2% by mass.

[0021] The fatty acids having 12 to 24 carbon atoms as component (C) of the present invention include behenic acid, stearic acid, isostearic acid, oleic acid, 12-hydroxystearic acid, coconut oil fatty acid, etc. The total amount of these is 0.1 to 1.0% by mass.

[0022] The component (D) of the present invention, an ester of a fatty acid having 12 to 24 carbon atoms and glycerin, is an ester of a fatty acid such as lauric acid, oleic acid, or stearic acid with glycerin, such as glyceryl laurate, glyceryl oleate, or glyceryl stearate, and the total amount thereof is, for example, 0.1 to 1.5% by mass.

[0023] In the component (E) of the present invention, an ester of a fatty acid having 12 to 24 carbon atoms and a glycerin polymer, the fatty acid is lauric acid, stearic acid, etc., and the glycerin polymer is hexaglycerin, decaglycerin, etc., and examples thereof include polyglyceryl-6 laurate, polyglyceryl-6 stearate, polyglyceryl-10 stearate, polyglyceryl-10 distearate, polyglyceryl-10 tristearate, etc. For example, the total amount of these is 0.1 to 1.5% by mass.

[0024] The collagen and / or hydrolyzed collagen as component (F) of the present invention is, for example, succinyl atelocollagen, water-soluble collagen, hydrolyzed collagen, hydrolyzed collagen ethyl, or the like.

[0025] (G) Ceramide NP is also known as N-stearoylphytosphingosine.

[0026] The primary particle size of the oil-in-water emulsion composition of the present invention is adjusted to 1 μm or less, which allows Brownian motion. This can be achieved by using a machine such as a high-pressure homogenizer or by surface science techniques such as optimizing the surfactant composition. The electrical conductivity of the oil-in-water emulsion composition of the present invention does not need to be particularly limited as long as aggregation occurs upon contact with the skin. However, for example, an oil-in-water composition with a value of 500 μS / cm or more tends to be less likely to aggregate upon contact with the skin, and therefore a lower electrical conductivity is preferred, with an electrical conductivity of 100 μS / cm or less being more preferred.

[0027] Since this is an oil-in-water emulsion composition that aggregates due to the natural moisturizing factors present in the skin, in addition to dropping it onto the skin to observe aggregation, 0.1 parts by weight of the simulated natural moisturizing factor aqueous solution was added to 100 parts by weight of the oil-in-water emulsion composition of the present invention, and after stirring and homogenizing for 3 minutes, the presence or absence of aggregation was evaluated using visual observation, microscopic observation, and a particle size distribution meter measurement as a guideline, based on an increase of 20% or more in the average particle size measured by the particle size distribution meter. Because a difference of ±10% between the average particle size measured by the particle size distribution meter increases the error factor, an increase of 20% or more was used as the standard. The average particle size was taken as the median diameter.

[0028] The oil-in-water emulsion composition of the present invention contains components (A), (B), (C), (D), and (E), but other components can be blended to the extent that the effects are not affected. For example, other components include surfactants such as PEG-35 hydrogenated castor oil, PEG-40 glyceryl cocoate, PEG-10 isostearate, sucrose distearate, decyl glucoside, and sodium laurate, oily substances such as cetyl lactate, octyl methoxycinnamate, meadowfoam oil, dimethicone, myristyl myristate, cholesteryl macadamiate, cholesterol, stearyl glycyrrhetinate, ubiquinone, tocopherol, and retinol, sodium alginate, carbomer, Polymers such as hydroxyethyl cellulose and polyvinyl alcohol, water-soluble substances such as glycine, propylene glycol, ethanol, ascorbic acid, maltitol, edetic acid, phytic acid, sodium chloride, arbutin, and allantoin, vegetable oils, synthetic oils, silicones, water-soluble polymers, ceramides, vitamins, amino acids, herbal extracts, fragrances and essential oils, preservatives, polyols and alcohols, sugars, powders, surfactants, and the like can be blended within the range in which aggregation occurs when the simulated natural moisturizing factor aqueous solution is added.

[0029] Elderly panelists commented that low-viscosity formulations drip during use, making them difficult to use. Therefore, a technology was sought to achieve a non-dripping viscosity while maintaining the skin's ability to aggregate with electrolytes. Adding collagen and / or hydrolyzed collagen at a concentration that results in an electrical conductivity of 100 μS / cm or less induces gentle aggregation, enabling the formulation to achieve a viscosity of 1 Pa·s or greater. This allows for a composition that maintains its fine primary particle size over time. Because of this gentle aggregation, viscosity increase is slow, and viscosity measurements are taken the day after preparation. Viscosity decreases immediately upon application. Microscopic observation reveals that the formulations are aggregated while maintaining primary particles, but particle size measurements (using a HORIBA Dynamic Light Scattering Particulate Size Analyzer LB-550) measure secondary particles, resulting in an average particle size of 1 μm or greater. The gentle aggregation results in a formulation that blends smoothly without greasiness, provides skin clarity, and moisturizing power comparable to those without collagen or hydrolyzed collagen, yet does not drip.

[0030] Ceramides are polar, and depending on the type (e.g., ceramide NG, ceramide AP, or ceramide NP), the properties, stability, and particle size of the oil-in-water emulsion composition are affected. However, when ceramide NP is used, the content of particles with a particle size of 1 μm or more (which is rarely observed) is low, the particle size distribution is narrow, and the texture feels cohesive, with good quality maintenance and stability.

[0031] When the composition is liquid, it is possible to visually observe aggregation by simply dropping it onto the skin. The simulated aqueous solution of natural moisturizing factors was prepared based on the information on the composition and amount of skin's natural moisturizing factors described in the Background Art. The standard was 0.1 parts by weight of the simulated aqueous solution of natural moisturizing factors per 100 parts by weight of the oil-in-water emulsion composition of the present invention. It is also possible to change the concentration of the simulated aqueous solution of natural moisturizing factors and to change the standard of response to skin condition when designing a formulation.

[0032] (Table 1) Example 1, Comparative Example 1 [How to create] Example 1 was prepared by heating and stirring each of the ingredients (A) and (B) listed in Table 1 to 80°C, adding (B) while stirring (A), emulsifying with a homomixer, processing with a high-pressure homomixer, stirring to 35°C, cooling, adding (C) and stirring and homogenizing. Comparative Example 1 was prepared by heating and stirring each of the ingredients (A) and (B) to 80°C, adding (B) while stirring (A), emulsifying with a homomixer, stirring to 35°C, cooling, adding (C) and stirring and homogenizing.

[0033] Example 1 and Comparative Example 1 had the same composition but different particle sizes, with Example 1 being liquid and Comparative Example 1 being creamy. 20 g of Example 1 was taken and 0.02 g of the simulated natural moisturizing factor aqueous solution was added. After stirring and homogenization, the particle size was measured. It was larger than before addition, and aggregates were also visually observed. The same amount of the simulated natural moisturizing factor aqueous solution was added to Comparative Example 1, but there was no change in particle size or visual observation. Ten evaluators evaluated the skin condition after using a facial cleanser. The average score was calculated as follows: 1 indicates no shine or transparency, and 5 indicates some shine. When the same amounts of the liquid Example 1 and the cream Comparative Example 1 were used, Example 1 provided transparency and was particularly free of shine, resulting in a significant difference. Example 1 clearly had the advantage of being quickly absorbed and leaving skin without shine. Shine evaluation criteria Score 1 None Score 2: Almost no tenor Score 3: Slightly shiny Score 4: Shiny Score 5: Strong shine Transparency evaluation criteria Score 1 None Score 2: Almost no transparency Score 3: Slightly transparent Score 4: Transparent Score 5: Strong transparency

[0034] Viscosity (25°C) was measured using a TOKI SANGYO VICOMETER TVB-10 with a No. 3 spindle at 100 rpm after 1 minute. For high viscosity, the viscosity was measured using a No. 5 spindle at 5 rpm after 1 minute. The electrical conductivity (25°C) was measured using a conductivity meter MPC70 manufactured by AS ONE.

[0035] The average particle size (25°C) was measured using a HORIBA Dynamic Light Scattering Particle Size Analyzer LB-550 manufactured by Horiba Ltd. The median size was used as the measured value. Comparison with an optical microscope confirmed that the secondary particle size could be measured. [Example]

[0036] [Table 1]

[0037] When Example 1 was dropped onto the palm of the hand, 9 out of 10 people experienced clumping and formation of lumps. The soap-type facial cleanser was used, and the face wash was left to soak into the skin for 1 minute each time, followed by rinsing with water. After washing three times, the skin was left to dry, and when the product was dropped onto the palm of the hand, no clumping was observed even after 3 minutes.

[0038] A test of Example 1 was conducted on 10 people using a soap-type facial cleanser without washing their face and with washing their face three times. The condition of the skin was observed after use. A clear difference was observed in terms of shine, with a score of 3.4 without washing their face and 1.0 with washing their face three times. The transparency score was 3.8 without washing their face and 4.3 with washing their face three times. Since excessive use of facial cleanser causes the skin to become dry and lose transparency, the effect was significant and corresponded to the skin condition.

[0039] A test was conducted on the inside of the forearm using a soap-type facial cleanser in the same manner, dropping Example 1 every time the face was washed, and sampling after 1 minute to measure particle size. The test results are shown in Figure 1. Using the facial cleanser reduced aggregation and reduced particle size. This is presumably due to the presence or absence of natural moisturizing factors, which are electrolytes that can be washed away. Although there are electrolytes in the skin that do not wash away, it is thought that the influence of natural moisturizing factors is significant.

[0040] When comparing the skin moisture content over time using Example 1 and Comparative Example 1, Comparative Example 1 initially showed a higher value, but Example 1 showed less skin moisture loss over time. Figure 2 shows the results, including an unused blank. The values ​​are the average of five panelists. For the test, 0.1 g of the sample was applied to a 2 cm x 5 cm area on the inside of the forearm, and skin moisture over time was measured using a skin moisture meter MC-607 manufactured by Rozenstar Co., Ltd., starting 10 minutes after the moisture from the sample evaporated. Skin moisture of 36% or less is described as having low skin moisture, while skin moisture of 47% or more is very moist. Example 1 initially had lower skin moisture than Comparative Example 1, but maintained skin moisture with less loss of skin moisture over time.

[0041] Five panelists used appropriate amounts of Example 1 and Comparative Example 1 on their faces after one soap-type face wash and three washes, and the amounts used were examined. The three washes were conducted on drier skin. The average amounts used were 0.259 g for Example 1 after one wash, 0.205 g for Comparative Example 1, 0.392 g for Example 1 after three washes, and 0.211 g for Comparative Example 1. Since Example 1 after three washes did not aggregate, it felt like a lotion, and it is thought that a larger amount was used appropriately.

[0042] Example 2, Comparative Example 2 Example 2 and Comparative Example 2 were prepared by heating and stirring the components (A) and (B) listed in Table 1 to 80°C, adding (B) while stirring (A), emulsifying with a homomixer, processing with a high-pressure homomixer, stirring to 35°C, cooling, adding (C), stirring, and homogenizing. Despite the same particle size and viscosity, Example 2 aggregated upon the addition of the simulated NMF aqueous solution, while Comparative Example 2, which did not contain an ester substance of fatty acid and glycerin, did not aggregate. When Example 2 was applied to the skin and aggregated, it changed to a thick texture, resulting in a sense of aggregation (richness). The sense of aggregation and transparency were evaluated by 10 evaluators. Comparative Example 2 did not aggregate, so it felt like a lotion and no sense of aggregation was felt. Cohesiveness evaluation criteria Score 1 None Score 2: Slightly Score 3 Yes Score 4: Strongly felt Score 5: Straightforward and very strong

[0043] (Table 2) Examples 3 to 5, Comparative Examples 3 to 5 Examples 3 to 5 and Comparative Examples 3 to 5 were prepared by heating and stirring ingredients (A) and (B) listed in Table 2 to 80°C, adding (B) while stirring (A), emulsifying with a homomixer, processing with a high-pressure homomixer, stirring to 35°C, and cooling. Example 3 and Comparative Example 3 differ in the use of oil with an IOB of 0.05 or less and other oils, Example 4 and Comparative Example 4 are examples with low oil content and differ in the presence or absence of higher alcohol, and Example 5 and Comparative Example 5 differ in the presence or absence of fatty acids. In each example, aggregation was observed upon addition of the simulated natural moisturizing factor aqueous solution.

[0044] [Table 2]

[0045] (Table 3) Examples 6 to 9, Comparative Examples 6 and 7 Examples 6-9 and Comparative Examples 6 and 7 were prepared by heating and stirring components (A) and (B) listed in Table 3 to 80°C, gradually adding (B) while stirring (A), stirring to 45°C, cooling, and then gradually adding (C) after stirring until homogenized, stirring to 35°C, cooling. Example 6 and Comparative Examples 6 and 7 compare the presence or absence of fatty acid glyceryl and fatty acid polyglyceryl. Examples 7-9 are SDG-type formulations that are plant-derived and allow all components to be obtained. Examples 7-9 varied the amount of higher alcohol and fatty acid blended; when too much was added, the addition of the simulated natural moisturizing factor aqueous solution promoted aggregation and increased particle size.

[0046] [Table 3]

[0047] Unlike conventional emulsions, this oil-in-water emulsion composition exhibits an extremely high tendency to aggregate. Even when the composition and manufacturing method are limited, variations in the surfactant lot size and preparation can lead to variations in the product. If the particle size is too small, Brownian motion becomes intense, slowing the aggregation reaction; if the particle size is too large, Brownian motion becomes sluggish, resulting in poor stability. Large variations in particle size distribution also slow the aggregation reaction and poor stability. Therefore, the quality was assessed by adding the simulated natural moisturizing factor aqueous solution and examining whether aggregation occurred. The number of samples and the number of samples that aggregated after adding the simulated natural moisturizing factor aqueous solution are listed in Tables 2 and 3. In the examples, nine of the ten samples had an average particle size that increased by 20% or more, and aggregates were visible to the naked eye. However, one sample had an average particle size of less than 20%, and no visible aggregation was observed, resulting in the sample being deemed unacceptable.

[0048] Examples 10-11, Comparative Examples 8-9 Examples 10-11 and Comparative Example 9 were prepared by heating and stirring the components (A) and (B) listed in Table 4 to 80°C, respectively, adding (B) while stirring (A), emulsifying with a homomixer, processing with a high-pressure homomixer, stirring to 35°C, cooling, and adding (C), stirring and mixing. After emulsification to an average particle size of 1 μm or less, hydrolyzed collagen, water-soluble collagen, and xanthan gum were added. Comparative Example 8 was prepared by heating and stirring (A), (B) + (C), respectively, to 80°C, adding (B) + (C) while stirring (A), emulsifying with a homomixer, stirring to 35°C, and cooling. The composition of Comparative Example 8 was the same as that of Example 10, but the emulsification step to an average particle size of 1 μm or less was omitted. Example 10 had primary particles of 1 μm or less, while Comparative Example 8 had an average primary particle size of 4.7 μm. Figure 3 shows the results of a comparison of skin moisture content similar to that described above, with Example 10 maintaining higher moisturizing power over time than Comparative Example 8. There was less shine and a transparent feel. Example 10, which is a secondary particle dispersion system in which hydrolyzed collagen is added and gently aggregated, has a primary particle size of 1 μm or less and a secondary particle size of 1 μm or more, and by setting the electrical conductivity to 100 μS / cm or less, it has a viscosity that does not drip during use, and provides skin care effects similar to those of a primary particle dispersion system.

[0049] Example 11 and Comparative Example 9 were prepared by emulsifying the same composition with an average particle size of 1 μm or less, and then adding water-soluble collagen in Example 11 and xanthan gum in Comparative Example 9. Example 11 aggregated upon the addition of the simulated natural moisturizing factor aqueous solution, while Comparative Example 9 did not. Differences were also observed in shine and transparency. The secondary particle dispersion composition, which was gently aggregated by adding water-soluble collagen, had a primary particle size of 1 μm or less and a secondary particle size of 1 μm or more, and by adjusting the electrical conductivity to 100 μS / cm or less, it had a viscosity that did not drip during use, and provided skin care effects similar to those of Examples 1 to 9, which were primary particle dispersions.

[0050] [Table 4] [Industrial Applicability]

[0051] The emulsion composition of the present invention can be used in products to be applied to the skin, such as cosmetics, quasi-drugs, and pharmaceutical compositions.

Claims

1. (A) 0.1 to 10.0 mass% of one or more oils selected from oils with an organic conceptual diagram IOB value of 0.05 or less; (B) 0.1 to 1.2 mass% of one or more selected from higher alcohols having 14 to 24 carbon atoms; (C) 0.1 to 1.0 mass% of one or more fatty acids selected from fatty acids having 12 to 24 carbon atoms; (D) one or more esters of a fatty acid having 12 to 24 carbon atoms and glycerin, and (E) one or more esters of a fatty acid having 12 to 24 carbon atoms and glycerin polymers, An oil-in-water emulsion composition having a primary particle size of 0.145 to 1.0 μm and an electrical conductivity of 100 μS / cm or less, This oil-in-water emulsion composition is characterized in that it aggregates when 0.1 parts by weight of a simulated aqueous solution of a natural moisturizing factor (a solution containing 78.93 wt % purified water, 13.54 wt % PCA-Na, 5.95 wt % sodium lactate, 0.51 wt % serine, 0.34 wt % glycine, 0.25 wt % glutamic acid, 0.14 wt % alanine, 0.12 wt % arginine, 0.12 wt % lysine, 0.07 wt % threonine, and 0.03 wt % proline) is added to 100 parts by weight of this oil-in-water emulsion composition.

2. 2. The oil-in-water emulsion composition according to claim 1, further comprising (F) collagen and / or hydrolyzed collagen.

Images