High internal oil phase water-oil type emulsion composition

Abstract

Provided is a high internal oil phase oil-in-water emulsion composition that has excellent emulsion stability. The high internal oil phase oil-in-water emulsion composition of the present disclosure comprises water and oil droplets dispersed in the water, the oil droplets comprising an aggregate comprising a cationic polymer and an anionic polymer, and an oil component, the oil component comprising 50% or more of the total amount of the water and the oil component, and the aggregates being present at the interface between the oil droplets and the aqueous phase.

Description

[Technical Field]

[0001] The present disclosure relates to high internal oil phase oil-in-water emulsion compositions. [Background technology]

[0002] BACKGROUND ART In recent years, oil-in-water emulsion compositions containing a high level of oil have been used in cleansing cosmetics and the like.

[0003] Patent Document 1 discloses an oil-in-water emulsion composition that is optimal as a cleansing agent, which is composed of a blend of (a) 5 to 30 mass % of glycerin, (b) 1 to 15 mass % of water, (c) 50 to 90 mass % of polar oil, and (d) 0.1 to 5 mass % of a polyglycerol fatty acid ester having a degree of polymerization of 5 to 6.

[0004] Patent Document 2 discloses an oil-in-water emulsion composition that contains an oily component, an aqueous component, and a surfactant, wherein the oily component accounts for 40% by mass or more of the total composition, and the oily component comprises 0.2 to 4.0% by mass of a solid fat having a melting point of 45 to 75°C of the total composition; in a test in which 0.3 g of the oil-in-water emulsion composition is applied to the inside of the forearm and the second, third, and fourth fingers are moved in circles with a load of 0.1 to 8.0 N, with a major axis of 10 cm and a minor axis of 5 cm, the emulsifier-type begins to change into an oily form after 1 to 20 circles, demonstrating excellent cleansing power.

[0005] Patent Document 3 discloses a high internal oil phase oil-in-water emulsion composition that contains 70 to 90% by weight of fats and oils and does not contain higher alcohols, and is suitable for cosmetics.

[0006] Patent Document 4 discloses an oil-in-water emulsion cosmetic for skin, which contains one or more polyglyceryl fatty acid esters, one or more N-long-chain acyl acidic amino acids and salts thereof, and one or more oily substances, the content of the oily substances being 30 to 70 wt % of the total weight of the cosmetic. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-153754 [Patent Document 2] Japanese Patent Application Publication No. 2018-111667 [Patent Document 3] Japanese Patent Application Laid-Open No. 2000-015085 [Patent Document 4] Japanese Patent Application Laid-Open No. 2002-212029 Summary of the Invention [Problem to be solved by the invention]

[0008] In conventional oil-in-water emulsion compositions, surfactants are generally used to highly emulsify oil. However, the surfactants used in such emulsion systems are generally not retained near the interface between the oil droplets (emulsion particles) and the aqueous phase, but are considered to be in an equilibrium state where they can move, for example, to the aqueous phase or to the interface of other adjacent oil droplets. As a result, exposed portions of the oil are generated at the interface of the oil droplets, and in particular, in high-internal-oil-phase oil-in-water emulsion compositions, the oil tends to aggregate and coalesce with the oil in other adjacent oil droplets, which tends to reduce emulsion stability.

[0009] Therefore, an object of the present disclosure is to provide a high internal oil phase oil-in-water emulsion composition that has excellent emulsion stability. [Means for solving the problem]

[0010] <Aspect 1> It contains water and oil droplets dispersed in the water, the oil droplets contain an association body containing a cationic polymer and an anionic polymer, and an oil component; The oil content is 50% or more of the total amount of the water and the oil content, The aggregate is present at the interface between the oil droplet and the aqueous phase. Takauchi oil phase oil-in-water emulsion composition. <Aspect 2> Aspect 2. The composition of aspect 1, wherein the oil content is 74% or more of the total amount of the water and the oil content. <Aspect 3> Aspect 3. The composition of aspect 1 or 2, wherein the cationic polymer and the anionic polymer are not themselves surfactants. <Aspect 4> Aspect 4. The composition of any one of aspects 1 to 3, wherein the cationic polymer has a degree of cationization of 0.5 meq / g or more, and the anionic polymer has a degree of anionization of 0.5 meq / g or more. <Aspect 5> the cationic polymer contains at least one component selected from the group consisting of diallyldimethylammonium chloride, 3-(methacrylamido)propyltrimethylammonium chloride, propyltrimonium chloride acrylamide, dimethylmethylenepiperidinium chloride, hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether, hydroxyethyl cellulose, guar gum hydroxypropyltrimethylammonium chloride ether, cationized locust bean gum, dimethylallylammonium chloride-acrylamide copolymer, and chitin-chitosan; and The anionic polymer contains at least one component selected from the group consisting of hyaluronic acid, carboxyvinyl polymer, carboxymethyl cellulose, acrylic acid, methacrylic acid, styrene sulfonic acid, acroyldimethyltaurine, ammonium acroyldimethyltaurine, alginic acid, aspartic acid, chondroitin sulfate, polyglutamic acid, and salts thereof. A composition according to any one of aspects 1 to 4. <Aspect 6> The cationic polymer contains at least one component selected from hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether and diallyldimethylammonium chloride, and The anionic polymer comprises at least one component selected from the group consisting of hyaluronic acid, carboxyvinyl polymer, carboxymethyl cellulose, and salts thereof. A composition according to any one of aspects 1 to 4. <Aspect 7> A cosmetic base comprising the composition according to any one of aspects 1 to 6. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide a high internal oil phase oil-in-water emulsion composition having excellent emulsion stability.

[0012] In conventional high internal phase emulsions obtained using surfactants, when a shear force equivalent to that applied to the skin is applied, the emulsion particles suddenly coalesce, resulting in a "phase inversion" sensation, where the emulsion spreads easily. The high internal oil phase oil-in-water emulsion composition of the present disclosure is characterized by a faster and larger change than in systems using such surfactants, providing a novel and unprecedented feeling when used. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a graph showing the change over time in the spreadability of an oil-in-water emulsion composition with an oil content of 75%. [Figure 2] 1 is a graph showing the change over time in the spreadability of an oil-in-water emulsion composition with an oil content of 40%. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present invention.

[0015] A high internal oil phase oil-in-water emulsion composition according to one embodiment of the present disclosure comprises water and oil droplets dispersed in the water, the oil droplets comprising an aggregate comprising a cationic polymer and an anionic polymer, and an oil component, the oil component comprising 50% or more of the total amount of the water and the oil component, and the aggregates being present at the interface between the oil droplets and the aqueous phase.

[0016] Without being limited by any particular theory, the mechanism by which the oil-in-water emulsion composition of the present disclosure contains a high amount of oil and exhibits excellent emulsion stability is believed to be as follows.

[0017] The aggregates contained in the high internal oil phase oil-in-water emulsion composition of the present disclosure are also called polyion complexes, and are aggregates having a structure in which cationic polymers and anionic polymers are aggregated and entangled due to electrostatic interactions, etc., and are in a state similar to solid particles. Furthermore, in emulsion compositions containing oil, such aggregates exist at the interface between the aqueous phase, which is the continuous phase, and the oil phase, which is the dispersed phase, and function like an emulsifier.

[0018] In oil-in-water emulsion compositions, surfactants are generally used as emulsifiers. Such surfactants generally do not remain near the interface between the oil droplets and the aqueous phase, but are in an equilibrium state where they can migrate to other locations, such as the aqueous phase. As a result, exposed oil portions are generated at the interface of the oil droplets, and particularly in high-internal-oil-phase oil-in-water emulsion compositions, the oil is likely to aggregate and coalesce with the oil in other adjacent oil droplets, resulting in reduced emulsion stability.

[0019] On the other hand, in the case of the oil-in-water emulsion composition of the present disclosure, the aggregates formed at the interface between the oil droplets and the aqueous phase are aggregates with an entangled structure due to electrostatic interactions or the like, and exhibit a solid state containing water. In other words, the system of the present disclosure can be considered a type of Pickering emulsion stabilized by solid particles. Unlike surfactants, the aggregates formed at the interface between the oil droplets hardly peel off from the interface. Because the oil phase and the aqueous phase can be physically separated, the emulsion stability when left standing is improved compared to general surfactants.

[0020] Furthermore, the oil-in-water emulsion composition of the present disclosure can contain a high amount of oil, at 74% or more of the total amount of water and oil. The oil-in-water emulsion composition of the present disclosure is believed to be able to contain oil more stably in the composition than in a state of a close-packed structure, because the emulsion particles are flexible droplets, unlike inorganic particles, and the above-mentioned aggregates are formed at the interfaces of the oil droplets, sufficiently stabilizing the emulsion particles.

[0021] Furthermore, in general, when the internal oil phase is in a close-packed state, i.e., when the volume of the internal oil phase exceeds 74% of the total volume of water and oil, the emulsion particles come into close proximity, and the resulting frictional force thickens the system even without the inclusion of a thickener in the external aqueous phase. The polymers that form the aggregates in the system of the present disclosure include those that have thickening properties on their own, but lose this thickening property when they form aggregates. However, when the system contains 74% or more of the internal oil phase, the system can be thickened even if the thickening property of the aggregates is lost.

[0022] 《Takauchi oil phase oil-in-water emulsion composition》 The high internal oil phase oil-in-water emulsion composition of the present disclosure (sometimes simply referred to as "emulsion composition") contains water and oil droplets dispersed in the water, the oil droplets containing an aggregate containing a cationic polymer and an anionic polymer, and an oil component, the oil component accounts for 50% or more of the total amount of the water and the oil component, and the aggregate is present at the interface between the oil droplets and the aqueous phase.

[0023] The emulsion composition of the present disclosure has excellent emulsion stability. Here, emulsion stability refers to a state in which the size of emulsion particles (oil droplets) remains unchanged for at least one month at 50°C or for at least three months at room temperature (5 to 35°C), for example.

[0024] The emulsion composition of the present disclosure also exhibits excellent emulsion stability even at low viscosities. The viscosity of the emulsion composition can be evaluated using, for example, an MCR-302 rheometer (manufactured by Anton-Paar). For example, the viscosity of the object being measured in the linear region at a shear rate of 1,000 / s, measured at 32°C and 1 atmosphere, 5 seconds after the start of shearing, can be defined as 800 mPa·s or more, 900 mPa·s or more, or 1,000 mPa·s or more, or 10,000 mPa·s or less, 9,500 mPa·s or less, or 9,000 mPa·s or less.

[0025] The size of the oil droplets (average particle size) can be defined as, for example, the average value of the diameters of the projected area circles of 10 or more oil droplets observed under an optical microscope, or, assuming that the oil droplets have a spherical particle shape, the average value of the diameters of the oil droplets optically measured by dynamic light scattering, etc. Furthermore, if the ratio of the internal oil phase exceeds 74%, the oil droplets may come into contact with each other and not maintain their spherical shape. In such cases, the system may be diluted with water before measurement.

[0026] As described above, the emulsion composition of the present disclosure provides a novel and unprecedented feeling of use, in which the "phase inversion sensation" in which the spreadability suddenly becomes lighter when a shear force equivalent to that applied to the skin is applied is rapid and significant, compared to conventional high internal phase emulsions obtained using surfactants.

[0027] Such a feeling of use (change in the phase inversion sensation) can be evaluated, for example, using a Tribomaster (manufactured by Trinity Lab Co., Ltd.) described below, based on the change in the weight of extension (sometimes simply referred to as "weight of extension"). For example, the emulsion composition of the present disclosure can achieve a reduction rate of the weight of extension calculated by the following formula 1 of 20% or more, 25% or more, or 30% or more. There is no particular upper limit to the reduction rate, but it can be specified as, for example, 80% or less, 75% or less, or 70% or less.

[0028] The rate of decrease in the spread weight of the emulsion composition can be calculated from the spread weight of the emulsion composition 1 second after the start of measurement and the spread weight of the emulsion composition 20 seconds after the start of measurement using the following formula 1: Decrease rate of spread weight (%)={(spread weight of emulsion composition 1 second after start of measurement−spread weight of emulsion composition 20 seconds after start of measurement)×100} / (spread weight of emulsion composition 1 second after start of measurement) ...Equation 1

[0029] <Oil drop> The oil-in-water emulsion composition of the present disclosure contains oil droplets as an oil phase or dispersed phase, and the oil droplets contain an association comprising a cationic polymer and an anionic polymer, and an oil component.

[0030] (Association) When a cationic polymer and an anionic polymer are mixed in an aqueous solution, the two polymers aggregate and entangle due to at least electrostatic interactions to form aggregates (solid particles) also called polyion complexes. Depending on the types of the two polymers, hydrophobic interactions may also be involved.

[0031] The size (average particle size) of the aggregates is preferably 10 nm or more, or 50 nm or more, and preferably 50 μm or less, 10 μm or less, or 1 μm or less. When the aggregate size is within this range, the adhesion of the aggregates at the oil-water interface can be improved, and relatively small emulsion particles can be prepared.

[0032] The size of the aggregate can be measured, for example, by dynamic light scattering (DLS) using an aqueous dispersion containing the aggregate.

[0033] The blending ratio of the cationic polymer and the anionic polymer can be determined, for example, by the molar ratio of the ionic charge of the anionic polymer to the ionic charge of the cationic polymer. This molar ratio can be in the range of 20:1 to 1:20, and preferably in the range of 15:1 to 1:15. The associations obtained by mixing the two polymers in this range, particularly in the range that allows ionically neutralization, tend to form at the interface between the oil droplets and the aqueous phase without precipitating.

[0034] From the viewpoint of emulsion stability of the emulsion composition, the total amount of the cationic polymer and anionic polymer to be blended can be 0.05% by mass or more, 0.07% by mass or more, or 0.1% by mass or more, and can be 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, 3% by mass or less, or 2% by mass or less, relative to the total amount of the emulsion composition.

[0035] a. Cationic polymer The cationic polymer of the present disclosure is not limited to the following, but may be, for example, a cationic polymer that does not exhibit surface activity by itself. Examples of such cationic polymers include cationic polymers having a degree of cationization of 0.5 meq / g or more, 0.7 meq / g or more, or 0.9 meq / g or more. The upper limit of the degree of cationization is not particularly limited, but may be, for example, 20 meq / g or less, 18 meq / g or less, or 15 meq / g or less. Here, the unit "meq / g" for the degree of cationization and the degree of anionization described below indicates how many millimoles of cationic dissociating groups (cationic ions) or anionic dissociating groups (anionic ions) are contained per gram of monomer constituting the cationic polymer or anionic polymer.

[0036] Specific examples of cationic polymers include diallyldimethylammonium chloride (DADMAC), 3-(methacrylamido)propyltrimethylammonium chloride (MAPTAC), propyltrimonium chloride acrylamide, dimethylmethylenepiperidinium chloride, hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether (cationized cellulose), hydroxyethyl cellulose (cationized HEC), guar gum hydroxypropyltrimethylammonium chloride ether (cationized guar gum), cationized locust bean gum, dimethylallylammonium chloride-acrylamide copolymer, and a homopolymer containing at least one component selected from the group consisting of chitin and chitosan. - Some examples include:

[0037] Among these, from the viewpoint of emulsion stability, thickening properties, etc., a homopolymer containing at least one component selected from hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether and diallyldimethylammonium chloride is preferred. - preferable.

[0038] From the viewpoint of emulsion stability of the emulsion composition, the amount of cationic polymer in the emulsion composition of the present disclosure can be 0.05% by mass or more, 0.07% by mass or more, or 0.1% by mass or more, relative to the total amount of the emulsion composition, and can be 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, 3% by mass or less, or 2% by mass or less.

[0039] b. anionic polymer The anionic polymer of the present disclosure is not limited to the following, but may be, for example, an anionic polymer that does not exhibit surface activity by itself. For example, an anionic polymer having a degree of anionization of 0.5 meq / g or more, 0.7 meq / g or more, or 0.9 meq / g or more may be used. The upper limit of the degree of anionization is not particularly limited, but may be, for example, 20 meq / g or less, 18 meq / g or less, or 15 meq / g or less.

[0040] Specific examples of the anionic polymer include a homopolymer containing at least one component selected from the group consisting of hyaluronic acid, carboxyvinyl polymer, carboxymethyl cellulose, acrylic acid, methacrylic acid, styrene sulfonic acid, acroyldimethyltaurine, ammonium acroyldimethyltaurine, alginic acid, aspartic acid, chondroitin sulfate, polyglutamic acid, and salts thereof. - Some examples include:

[0041] Among these, from the viewpoint of emulsion stability, thickening properties, etc., a single polymer containing at least one component selected from the group consisting of hyaluronic acid, carboxyvinyl polymer, carboxymethyl cellulose, and salts thereof is preferred. - preferable.

[0042] From the viewpoint of emulsion stability of the emulsion composition, the amount of the anionic polymer in the emulsion composition of the present disclosure can be 0.05% by mass or more, 0.07% by mass or more, or 0.1% by mass or more, relative to the total amount of the emulsion composition, and can be 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, 3% by mass or less, or 2% by mass or less.

[0043] c. Other cationic and anionic polymers In addition to the cationic polymer and anionic polymer described above, the emulsion composition of the present disclosure may contain other cationic polymers and anionic polymers within a range that does not impair the effects of the present disclosure. However, in consideration of emulsion stability and the like, it is preferable that the emulsion composition does not contain other cationic polymers and anionic polymers.

[0044] (oil content) The oil component is not limited to the following, but for example, at least one of liquid oils, solid oils, waxes, hydrocarbon oils, synthetic ester oils, silicone oils, and the like can be used.

[0045] 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 yolk oil, sesame oil, persic oil, wheat germ oil, camellia oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, Chinese tung oil, Japanese tung oil, jojoba oil, germ oil, and triglycerin.

[0046] Examples of solid fats and oils include cacao butter, coconut oil, horse fat, hardened coconut oil, palm oil, beef tallow, mutton tallow, hardened beef tallow, palm kernel oil, lard, beef bone fat, Japan wax kernel oil, hardened oil, beef trotter fat, Japan wax, and hardened castor oil.

[0047] 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, lanolin acetate, liquid lanolin, sugarcane wax, lanolin fatty acid isopropyl, hexyl laurate, reduced lanolin, jojoba wax, hard lanolin, shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, lanolin fatty acid polyethylene glycol, and POE hydrogenated lanolin alcohol ether.

[0048] Examples of hydrocarbon oils include liquid paraffin, ozokerite, squalane, pristane, paraffin, ceresin, squalene, petrolatum, microcrystalline wax, olefin oligomer, isododecane, and isohexadecane.

[0049] Examples of synthetic ester oils include isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, cholesteryl 12-hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid esters, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, and pentaerythritol tetra-2-ethylhexanoate. Ingredients: glycerin tri-2-ethylhexanoate, glycerin trioctanoate, glycerin triisopalmitate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glycerin trimyristate, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, acetoglyceride, 2-heptyl palmitate Examples of the alkyl acrylate copolymer include 2-hexylundecyl lauroyl glutamate, diisobutyl adipate, N-lauroyl-L-glutamic acid 2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, and triethyl citrate.

[0050] Examples of silicone oils include chain silicones such as dimethylpolysiloxane (dimethicone), methylphenylpolysiloxane, and methylhydrogenpolysiloxane; and cyclic silicones such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane.

[0051] The emulsion composition of the present disclosure may contain 50% or more, 60% or more, 70% or more, or 74% or more of oil relative to the total amount of water and oil. There is no particular upper limit to the content, but it may be specified as, for example, 85% or less, or 80% or less.

[0052] <water> The water that can be used in the emulsion composition of the present disclosure is not particularly limited, and can be water used in cosmetics, quasi-drugs, etc. For example, purified water, ion-exchanged water, tap water, etc. can be used.

[0053] <Optional ingredients> The emulsion composition of the present disclosure can be blended with various components as desired depending on the intended use of the emulsion composition, etc., within a range that does not impair the effects of the present disclosure. Examples of the various components include additives that are typically blended into cosmetics, etc., such as higher alcohols, lower alcohols, polyhydric alcohols, various extracts, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, humectants, antioxidants, buffers, preservatives, antioxidant aids, organic powders, pigments, dyes, colorants, fragrances, chelating agents, pH adjusters, UV absorbers, gelling agents (thickeners), etc.

[0054] The emulsion composition of the present disclosure preferably does not contain a separate surfactant from the viewpoints of emulsion stability, low irritation to the skin, etc., and preferably does not contain a separate gelling agent (thickener) from the viewpoints of usability, etc.

[0055] Depending on their nature, the various ingredients can be incorporated into the aqueous phase as the continuous phase and / or into the oil as the dispersed phase.

[0056] <<Uses of the emulsion composition>> The emulsion composition of the present disclosure can provide a moist feel when applied to the skin. Furthermore, compared to conventional high internal phase emulsions that use surfactants, the emulsion composition of the present disclosure can provide a feel of more pronounced disintegration of emulsion particles (a phase inversion sensation) when applied to the skin and spread. Furthermore, despite containing a high level of oil, the emulsion composition of the present disclosure is in an oil-in-water form, and therefore, unlike water-in-oil emulsion compositions, can be dispersed in water and can be washed off with water. Therefore, the emulsion composition of the present disclosure, which exhibits such properties, can be used, for example, as a cosmetic base, particularly as a cosmetic base to be applied to the skin.

[0057] Specifically, the emulsion composition of the present disclosure can be used, for example, as a cleansing cosmetic or skin cleanser such as a makeup remover or body shampoo, a sunscreen cosmetic (sunscreen agent), a massage cosmetic, a skin care cosmetic such as an emulsion, a makeup cosmetic, etc. It is particularly preferably used as a cleansing cosmetic or skin cleanser.

[0058] <<Method for producing emulsion composition>> The oil-in-water emulsion composition of the present disclosure can be produced using a known method. For example, both a cationic polymer and an anionic polymer are added to water and stirred to prepare a mixed solution, and an oil component is added to the mixed solution and stirred to obtain an oil-in-water emulsion composition. If necessary, the above-mentioned optional components may be appropriately blended with the water or oil component.

[0059] Alternatively, either a cationic polymer or an anionic polymer is added to a portion of the water to prepare a mixed solution, and an oil component is added to the mixed solution and stirred to emulsify the mixture to prepare emulsion solution A. Next, the other polymer is added to another portion of the water to prepare mixed solution B, and the mixed solution B is added to emulsion solution A and stirred to obtain an oil-in-water emulsion composition. If necessary, the above-mentioned optional components may be appropriately blended with the water or oil component. [Example]

[0060] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these. Note that, hereinafter, unless otherwise specified, the blending amounts are expressed in parts by mass.

[0061] Examples 1 to 4 and Comparative Examples 1 to 5 The emulsion compositions obtained by the production methods described below were evaluated as follows, and the results are shown in Table 1.

[0062] <Viscosity evaluation> Using an Anton Paar MCR302 rheometer, the viscosity was measured at a shear rate of 1000 / s under conditions of 32°C and 1 atmosphere. The viscosity in Table 1 indicates the viscosity 5 seconds after the start of shear. Here, viscosity measurement was not performed for compositions rated "C" in the emulsion stability evaluation below.

[0063] <Evaluation of emulsion stability> The size of the oil droplets within one hour after the emulsion composition was prepared and after storage at 50°C for one month was visually observed, and the emulsion stability was evaluated according to the following criteria: A: There was almost no change in the size of the oil droplets. B: The oil droplet size increased slightly. C: The oil droplet size was clearly increased.

[0064] <Method for producing emulsion composition> Example 1 A 5% by mass aqueous solution of an anionic polymer, a carboxyvinyl polymer (Carbopol™ 981 polymer, manufactured by Lubrizol Advanced Materials) with an anionization degree of 14.1 meq / g, and a cationic polymer, a cationized cellulose (UCARE™ Polymer JR-400 (hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether) manufactured by The Dow Chemical Company) with a cationization degree of 1.0 meq / g, was prepared. The solution containing the cationized cellulose and the solution containing the carboxyvinyl polymer were then mixed and stirred at room temperature in a mass ratio of 14:1 (ionically neutral) to prepare an aggregate. Deionized water was then added to this aggregate to prepare Dispersion A with a total polymer concentration of 3.33% or 1.00% by mass. Liquid paraffin, the oil component, was gradually added to Dispersion A at room temperature while stirring and mixing to achieve the oil content and polymer concentration in the emulsion composition listed in Table 1. Oil-in-water emulsion compositions were then prepared.

[0065] Example 2 The oil-in-water emulsion composition of Example 2 was prepared in the same manner as in Example 1, except that hyaluronic acid with an anionization degree of 2.6 meq / g (BioHyalo™ 12 manufactured by Shiseido Co., Ltd.) was used as the anionic polymer, and cationized cellulose with a cationization degree of 1.0 meq / g (UCARE™ Polymer JR-400 (hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether) manufactured by The Dow Chemical Company) was used as the cationic polymer.

[0066] Example 3 The oil-in-water emulsion composition of Example 3 was prepared in the same manner as in Example 1, except that carboxymethylcellulose (Cellogen (trademark) FSH manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) with an anionization degree of 1.5 meq / g and PDADMAC (Marquat (trademark) 100 (polydiallyldimethylammonium chloride) manufactured by Nalco Corporation) with a cationization degree of 6.2 meq / g were used as the anionic polymer and the cationic polymer, respectively.

[0067] Example 4 The oil-in-water emulsion composition of Example 4 was prepared in the same manner as in Example 1, except that carboxymethyl cellulose with an anionization degree of 1.5 meq / g (Cellogen™ F, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was used as the anionic polymer, and cationized cellulose with a cationization degree of 1.0 meq / g (UCARE™ Polymer JR-400 (hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether), manufactured by The Dow Chemical Company) was used as the cationic polymer.

[0068] (Comparative Example 1) An oil-in-water emulsion composition of Comparative Example 1 was prepared in the same manner as in Example 1, except that a microgel (manufactured by Toho Chemical Industry Co., Ltd. (N,N'-dimethylacrylamide-2-acrylamido-2-methylpropanesulfonate sodium-N,N'-methylenebisacrylamide copolymer)) with an anionization degree of 3.4 meq / g was used as the anionic polymer, and a MAPTAC-PAA copolymer (manufactured by Nalco Corporation under the trademark Merquat™ 2001 (a copolymer of 3-(methacrylamido)propyltrimethylammonium chloride and polyallylamine)) with a cationization degree of 3.2 meq / g was used as the cationic polymer. When a certain amount of oil was added to this emulsion composition, the oil was no longer emulsified, and a considerable amount of oil floated to the top.

[0069] (Comparative Example 2) The oil-in-water emulsion composition of Comparative Example 2 was prepared in the same manner as in Example 1, except that sodium alginate with an anionization degree of 5.7 meq / g (Duck Algin NSPH manufactured by Kikkoman Biochemifa Corporation) was used as the anionic polymer, and cationic locust bean gum with a cationization degree of 1.0 meq / g (Catinal (trademark) CLB-100 manufactured by Toho Chemical Industry Co., Ltd.) was used as the cationic polymer.

[0070] (Comparative Example 3) The composition of Comparative Example 3 was prepared in the same manner as in Example 1, except that dispersion A containing only an anionic carboxyvinyl polymer (Carbopol™ 981 polymer manufactured by Lubrizol Advanced Materials) with a degree of anionization of 14.1 meq / g and no aggregates was used. This composition turned white for a moment when mixed, but quickly separated like a separate-type dressing.

[0071] Comparative Example 4 The composition of Comparative Example 4 was prepared in the same manner as in Example 1, except that Dispersion A, which contained only hyaluronic acid with an anionization degree of 2.6 meq / g (BioHyalo (trademark) 12 manufactured by Shiseido Co., Ltd.) and did not contain aggregates, was used.

[0072] (Comparative Example 5) The composition of Comparative Example 5 was prepared in the same manner as in Example 1, except that Dispersion A containing no aggregates and only PDADMAC (Marquat (trademark) 100 (polydiallyldimethylammonium chloride) manufactured by Nalco) having a degree of cationization of 6.2 meq / g was used.

[0073] [Table 1]

[0074] <result> As can be seen from the results in Table 1, it was confirmed that the emulsion compositions containing aggregates such as those in Examples 1 to 4 were able to encapsulate 50% or more of the oil content, compared to the compositions clearly not containing aggregates such as those in Comparative Examples 3 to 5. The compositions in Comparative Examples 1 and 2 contained an anionic polymer and a cationic polymer, but were unable to encapsulate 50% or more of the oil content. This is thought to be due to the fact that the combinations of anionic polymer and cationic polymer in Comparative Examples 1 and 2 did not sufficiently form aggregates, or even if something resembling an aggregate was formed, it was not present at the interface between the oil droplets and the aqueous phase.

[0075] Example 5 and Comparative Example 6 The emulsion compositions obtained by the production methods described below were evaluated for the following spreadability (phase inversion sensation), and the results are shown in FIGS.

[0076] <Evaluation of stretchability (phase change sensation)> The spreading weight of the emulsion composition was measured using a Tribomaster manufactured by Trinity Lab Co., Ltd. In this measurement, 10 μl of a sample of the emulsion composition was placed on artificial leather, and the force applied when a 1 cm square tip was moved back and forth over the sample for 5 cm while a load of 50 g was applied at a speed of 5 cm / sec was measured.

[0077] Example 5 A 5% by mass aqueous solution of a carboxyvinyl polymer (Carbopol™ 981 polymer, manufactured by Lubrizol Advanced Materials) with an anionic degree of 14.1 meq / g and a cationic polymer (UCARE™ Polymer JR-400 (hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether) manufactured by The Dow Chemical Company) with a cationic degree of 1.0 meq / g was prepared. The solution containing the cationized cellulose and the solution containing the carboxyvinyl polymer were then mixed at room temperature with stirring at a mass ratio of 14:1 (ionically neutral) to prepare an aggregate. Deionized water was then added to this to prepare Dispersion B with a total polymer concentration of 3.33% by mass. Liquid paraffin (oil) was then gradually added to Dispersion B with stirring at room temperature to obtain an oil content of 74% and a polymer concentration of 0.96% by mass. This resulted in an oil-in-water emulsion composition.

[0078] (Comparative Example 6) The emulsion composition of Comparative Example 6 was prepared in the same manner as in Example 5, except that liquid paraffin was added to dispersion B so that the oil content was 40% and the polymer concentration in the emulsion composition was 1.4% by mass.

[0079] <result> As is clear from the results in Figure 1, the emulsion composition with a high oil content in Example 5 exhibited a peculiar phase inversion sensation, in which the spreadability dropped sharply within a range of about 20 seconds from the initial stage of measurement. On the other hand, as is clear from the results in Figure 2, the emulsion composition with a low oil content in Comparative Example 6 showed almost no change in spreadability from the initial stage of measurement until about 40 seconds, and did not exhibit any phase inversion sensation at all.

[0080] <<Formulation example of composition>> Formulation examples of the emulsion composition of the present disclosure are given below, but the present disclosure is not limited to these examples. When the cleansing agents described in the formulation examples below were simply applied to the skin, they were able to be fixed to the skin without dripping, but when the applied cleansing agents were spread over the skin surface, they gave a sensation of sudden disintegration of the emulsion particles (a phase inversion sensation).

[0081] Furthermore, despite containing a high level of oil, the resulting cleansing agent was in the form of an oil-in-water type, and therefore could be washed off with water, unlike cleansing agents consisting of an emulsion composition in the form of a water-in-oil type.

[0082] <Formulation example 1: Cleansing agent> (Component) (mass%) Purified water (appropriate amount) Carboxyvinyl polymer with an anionization degree of 14.1 meq / g 0.07 Cationized cellulose with a degree of cationization of 1.0 meq / g: 0.93 Isododecane 10 Dimethyl Silicone 30 Triethylhexanoin 10 Liquid Paraffin 24 1,3-butylene glycol 10 Ion-exchanged water Remaining Preservatives (appropriate amount) Fragrance (appropriate amount)

[0083] (Manufacturing method of cleansing agent) A carboxyvinyl polymer with an anionization degree of 14.1 meq / g and a cationized cellulose with a cationization degree of 1.0 meq / g were dissolved in ion-exchanged water to prepare 2% by mass and 5% by mass aqueous solutions, respectively. This aqueous solution, a moisturizer, and a preservative were stirred and mixed at room temperature to prepare dispersion a containing an aggregate. The oil and fragrance mixed in dispersion a were gradually added, and the mixture was stirred and mixed at room temperature to prepare a cleansing agent.

Claims

1. It contains water and oil droplets dispersed in the water, the oil droplets contain an association body containing a cationic polymer and an anionic polymer, and an oil component; The oil content is 60% or more and 85% or less of the total amount of the water and the oil content, the aggregates are present at the interface between the oil droplets and an aqueous phase, the cationic polymer contains at least one component selected from the group consisting of hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether and diallyldimethylammonium chloride; the anionic polymer comprises at least one component selected from the group consisting of hyaluronic acid, carboxyvinyl polymer, carboxymethyl cellulose, and salts thereof; A high internal oil phase oil-in-water emulsion composition, wherein the total amount of the cationic polymer and the anionic polymer is 0.1% by mass or more.

2. The composition according to claim 1 , wherein the oil content is 74% or more of the total amount of the water and the oil.

3. A cosmetic base comprising the composition according to claim 1 or 2.

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