HK1240097B - Co-emulsification composition containing various emulsification particle sizes and method for preparing same - Google Patents

Description

Mixed emulsion composition containing different emulsified particle sizes and preparation method thereof

【Technical field】

The present invention relates to a mixed emulsion composition in which emulsified particles of different sizes coexist in an emulsion system and exhibit the characteristics of each emulsified particle, and a preparation method thereof.

[Background Technology]

According to related art, the preparation of cosmetic emulsion compositions often focuses on making emulsified particles small and uniform, within the range of several microns or less, and stably obtaining emulsion compositions without particle coalescence. This is because it is important to prevent the so-called Ostwald ripening phenomenon (particle coalescence caused by differences in emulsified particle size) to ensure a stable emulsion system.

Emulsion systems exhibit their fundamental properties based on the size of their emulsified particles, and different particle sizes provide distinct user experiences. For example, nano-sized (hundreds of nanometers) emulsified particles exhibit moisturizing and nourishing properties. Micro-sized (several micrometers) emulsified particles are the typical emulsified particle size that exhibits soft spreadability in most cosmetic compositions.

However, when different emulsified particles are present in a single formulation, problems related to emulsion formulation stability (such as aggregation) can occur. Therefore, such different emulsified particles can only be mixed in very limited proportions. Furthermore, in conventional multiple emulsion systems, such as water-in-oil-in-water or oil-in-water-in-oil emulsions, the emulsified particles are inherently small, thus limiting their preparation and reproducibility, and thus limiting their industrial applicability.

[Summary of the invention]

[Technical Issues]

One of the technical problems solved by the present invention is to provide a mixed emulsion composition that solves the coagulation problem caused by the non-uniformity due to different emulsified particle sizes and the instability of the emulsified particles themselves, and allows emulsified particles of different sizes to coexist while achieving at least two different usage experiences or physical properties.

[Technical Solution]

Generally speaking, an emulsion composition having different emulsion particle sizes is provided. The emulsion composition comprises macroemulsion particles ranging from 1 micron to 100 microns and nanoemulsion particles ranging from 100 nanometers to 900 nanometers. The macroemulsion particles include an amphoteric anisotropic powder. The amphoteric anisotropic powder comprises a first hydrophilic polymer spheroid and a second hydrophobic polymer spheroid. The first and second polymer spheroids are bonded to each other in a structure in which one polymer spheroid at least partially penetrates the other polymer spheroid. The first polymer spheroid has a core-shell structure, and the shell layer thereof has a functional group.

According to one embodiment, the macroemulsified particles and the nanoemulsified particles are present in a ratio of 5-9:5-1.

According to another embodiment, the cores of the second polymer sphere and the first polymer sphere include vinyl polymer, and the shell of the first polymer sphere includes a copolymer of vinyl monomer and functional groups.

According to yet another embodiment, the vinyl polymer may include polystyrene.

According to yet another embodiment, the functional group may be siloxane.

According to yet another embodiment, the shell layer of the first polymer sphere may further include hydrophilic functional groups introduced therein.

According to another embodiment, the functional group may be at least one group selected from the group consisting of a carboxylic acid group, a sulfone group, a phosphate group, an amino group, an alkoxy group, an ester group, an acetate group, a polyethylene glycol group, and a hydroxyl group.

According to yet another embodiment, the amphoteric anisotropic powder may have a symmetric shape, an asymmetric snowman shape, or an asymmetric reverse snowman shape, depending on where the first polymer sphere and the second polymer sphere are bonded to each other.

According to yet another embodiment, the amphoteric anisotropic powder may have a particle size of 100 nm to 1500 nm.

In another general aspect, a method for preparing a mixed emulsion composition is provided, comprising: separately forming an emulsion composition comprising an amphoteric anisotropic powder for preparing macroemulsified particles having a particle size of 1 μm to 100 μm, and an emulsion composition comprising a surfactant for preparing nanoemulsified particles having a particle size of 100 nm to 900 nm, and mixing the emulsion compositions with each other.

In another general aspect, a method for preparing a mixed emulsion composition is provided, comprising: (a) introducing an amphoteric anisotropic powder for preparing large emulsified particles having a particle size of 1 μm to 100 μm into an aqueous phase and dispersing the powder therein; (b) introducing oil for a primary emulsification reaction; (c) introducing a thickener and a neutralizer and dispersing them therein; and (d) introducing a surfactant and oil for preparing nanoemulsified particles having a particle size of 100 nm to 900 nm for a secondary emulsification reaction.

[Beneficial Effects]

According to an embodiment of the present invention, a Pickering surfactant system using anisotropic amphoteric powders and a conventional emulsion system using surfactants are combined to create a non-interfering heterogeneous emulsion system. This makes it possible to provide a hybrid emulsion composition comprising emulsified particles of varying sizes coexisting in a single formulation, while simultaneously exhibiting at least two distinct user experiences and physical properties.

Furthermore, the emulsion composition disclosed herein is not a multiple emulsion system in which one type of emulsified particle exists within another type of emulsified particle. Instead, it is a single formulation in which emulsified particles of different sizes exist independently, enabling at least two or more different user experiences derived from each emulsified particle. The emulsified particles coexisting in the emulsion composition exhibit no aggregation, thus ensuring significantly greater stability than conventional multiple emulsion systems and enabling application in a wide variety of formulations and products.

【Brief Description of the Drawings】

Figure 1 shows microscopic images of mixed emulsion compositions obtained according to the individual emulsion mixing methods described in the Examples, wherein (a) shows an image of a formulation obtained by using emulsified particles of anisotropic powder (size: approximately tens of micrometers) and nanoemulsified particles (size: approximately 200 nanometers) using a general surfactant, taken immediately after preparation; (b) and (c) show the emulsified particle sizes after storage at 45°C for 2 weeks and 4 weeks, respectively; and (d) shows the results obtained by fluorescence imaging of the nanoemulsion in sample (c).

Figure 2 shows the particle size distribution of the mixed emulsion compositions obtained according to the individual emulsion mixing methods in the examples, wherein (a) shows the particle size distribution measured immediately after preparation (average value: approximately 200 nm), and (b) shows the particle size distribution measured four weeks later (average value: approximately 190 nm). Therefore, no significant difference was observed.

FIG3 shows the viscosity of the mixed emulsion compositions obtained according to the respective emulsion mixing methods in the examples as a function of time, which illustrates that the stability of the formulation can be maintained over a temperature range (-15 to 60° C.) without significant viscosity changes over time.

[Specific implementation method]

Exemplary embodiments will now be described more fully below with reference to the accompanying drawings, in which exemplary embodiments are shown. However, the present invention may be presented in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein. Furthermore, these embodiments are provided to make the present invention thorough and complete and to fully convey the scope of the invention to those skilled in the art. In the accompanying drawings, the shapes, sizes, areas, etc. of the figures may be exaggerated for clarity. In addition, although only a portion of the constituent elements are listed for ease of description, the remaining portions should be easily understood by those skilled in the art. Furthermore, those skilled in the art will also understand that various changes in form and details may be made without departing from the scope of the invention as defined by the present invention.

As used herein, "substituted" means that at least one hydrogen atom on a functional group described herein is replaced by a halogen atom (F, Cl, Br or I), a hydroxyl group, a nitro group, an imino group (=NH, =NR, wherein R is a C1-C10 alkyl group), an amidino group, a hydrazine or a hydrazine group, a carboxyl group, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C3-C30 heterocyclic aromatic group, or a substituted or unsubstituted C2-C30 heterocycloalkyl group, etc., unless otherwise specified.

As used herein, "(meth)acryl" refers to acryl and/or methacryl.

As used herein, the particle size of an amphoteric anisotropic powder is measured as the maximum length, i.e., the longest length of the powder particles. As used herein, a particle size range of an amphoteric anisotropic powder means that at least 95% of the amphoteric anisotropic powder present in the composition falls within the corresponding range.

As used herein, the average particle size of the emulsified particles refers to the average diameter of each particle. As used herein, the average particle size range of the emulsified particles refers to the range in which at least 95% of the emulsified particles in the composition fall within.

In one aspect, an emulsion composition having different emulsified particle sizes is provided, the emulsion composition comprising emulsified particles having a particle size of 100 nanometers to 100 micrometers, wherein the amphiphilic anisotropic powder comprises a first hydrophilic polymer sphere and a second hydrophobic polymer sphere; the first and second polymer spheres are bonded to each other in a structure in which one polymer sphere at least partially penetrates the other polymer sphere; the first polymer sphere has a core-shell structure; and its shell layer has a functional group.

According to one embodiment, the emulsion composition may include emulsified particles having an average particle size of 100 nanometers to 90 micrometers. For example, the average particle size of the emulsified particles may be 100 nanometers to 1000 nanometers or 100 nanometers to 900 nanometers.

In another aspect, an emulsion composition having different emulsified particle sizes is provided, comprising large emulsified particles having a size of 1 μm to 100 μm and nanoemulsified particles having a size of 100 nm to 900 nm, wherein the large emulsified particles comprise an amphoteric anisotropic powder; the amphoteric anisotropic powder comprises a first hydrophilic polymer sphere and a second hydrophobic polymer sphere; the first and second polymer spheres are bonded to each other in a structure in which one polymer sphere at least partially penetrates the other polymer sphere; and the first polymer sphere has a core-shell structure, wherein the shell layer has a functional group.

The mixed emulsion composition refers to an emulsion composition having emulsified particles of different sizes.

A mixed emulsion composition with emulsion particles of varying sizes exhibits the properties of each emulsion particle. In particular, a cosmetic composition comprising base emulsion particles (a few microns) and nanoemulsion particles (hundreds of nanometers) exhibits soft spreadability and a moisturizing and nourishing feel. This soft spreadability comes from the micron-sized emulsion particles, while the moisturizing and nourishing feel comes from the nanoemulsion particles, which are hundreds of nanometers in size. Because the emulsion composition contains an amphoteric anisotropic powder, it maximizes the size differences of the emulsion particles. This allows large emulsion particles ranging from 1 to 100 microns to be stably mixed with nanoemulsion particles ranging from 1 to 100 microns in size, allowing the user to tangibly perceive the properties of each particle type. In other words, the emulsion composition can provide a unique dual-use experience in a 2-in-1 or 3-in-1 formulation, thereby delivering the moisturizing feeling of the large emulsion particles and the comfortable nourishing feeling of the smaller emulsion particles.

Because the hydrophobic and hydrophilic portions of the amphoteric anisotropic powder have different orientabilities at the interface, it is possible to form large emulsified particles and provide a formulation with excellent usability. According to related art, it is difficult to form stable large emulsified particles with a particle size of tens of microns using molecular-level surfactants, which form an interfacial film with a thickness of approximately several nanometers. However, in the case of the amphoteric anisotropic powder disclosed in the present invention, the thickness of this interfacial film is increased to approximately hundreds of nanometers, forming a stable interfacial film thanks to the strong bonds between the powder particles, thereby significantly improving the stability of the emulsion.

As used herein, a sphere refers to a single entity formed from a polymer. For example, it may have a spherical or elliptical shape, and a major axis length of micrometer scale or nanometer scale depending on the maximum length of the main body.

According to one embodiment, the amphoteric anisotropic powder may be 0.1-15 weight percent of the total weight of the mixed emulsion composition. According to another embodiment, the chemically anisotropic powder may be 1-5 weight percent of the total weight of the emulsion composition. Specifically, the chemically anisotropic powder may be at least 1 weight percent, at least 2 weight percent, at least 4 weight percent, at least 6 weight percent, at least 8 weight percent, at least 10 weight percent, or at least 12 weight percent, and at most 15 weight percent, at most 12 weight percent, at most 10 weight percent, at most 8 weight percent, at most 6 weight percent, at most 4 weight percent, or at most 2 weight percent. The size of the emulsified particles can be controlled to be from a few microns to tens of microns or hundreds of microns by adjusting the content of the chemically anisotropic powder.

According to one embodiment, the ratio of macroemulsified particles to nanoemulsified particles is 5-9:5-1, or 7-9:3-1.

According to another embodiment, the cores of the second polymer sphere and the first polymer sphere include a vinyl polymer, and the shell of the first polymer sphere may include a copolymer of the vinyl polymer having a functional group.

According to another embodiment, the vinyl polymer may include a vinyl aromatic polymer, in particular polystyrene.

According to another embodiment, the functional group may be siloxane.

According to yet another embodiment, the shell of the first polymer sphere may have hydrophilic functional groups introduced therein.

According to another embodiment, the hydrophilic functional group can be a negatively charged or positively charged functional group or a polyethylene glycol-based (PEG) functional group, and can be selected from at least one of the following groups: a carboxylic acid group, a sulfone group, a phosphate group, an amino group, an alkoxy group, an ester group, an acetate group, a polyethylene glycol group, and a hydroxyl group.

According to yet another embodiment, the amphoteric anisotropic powder may have a symmetrical shape, an asymmetrical snowman shape, or an asymmetrical reverse snowman shape depending on the bonding portion where the first polymer sphere and the second polymer sphere are bonded to each other.

According to another embodiment, the amphoteric anisotropic powder may have a particle size of 100-1500 nanometers. In a variation, the amphoteric anisotropic powder may have a particle size of 100-500 nanometers, or 200-300 nanometers. Here, the particle size refers to the maximum length of the amphoteric powder. Specifically, the amphoteric powder may have a particle size of at least 100 nm, at least 200 nm, at least 300 nm, at least 400 nm, at least 500 nm, at least 600 nm, at least 700 nm, at least 800 nm, at least 900 nm, at least 1000 nm, at least 1100 nm, at least 1200 nm, at least 1300 nm or at least 1400 nm, at most 1500 nm, at most 1400 nm, at most 1300 nm, at most 1200 nm, at most 1100 nm, at most 1000 nm, at most 900 nm, at most 800 nm, at most 700 nm, at most 600 nm, at most 500 nm, at most 400 nm, at most 300 nm or at most 200 nm.

In another general aspect, a method for preparing a mixed emulsion composition is provided, comprising forming an emulsion composition comprising an amphoteric anisotropic powder for preparing large emulsified particles having a size of 1 to 100 microns, and an emulsion composition comprising a surfactant for preparing nanoemulsion particles having a size of 100 to 900 nanometers, and mixing the two emulsion compositions. Thus, the method is an individual emulsion mixing method, comprising preparing each emulsion composition separately and then simply mixing them. Thus, the mixing ratio of the emulsion compositions can be freely controlled.

According to one embodiment, the thickener may be at least one selected from the group consisting of carbomer, carbopol, gelatin, xanthan gum, natural cellulose, hydroxyethyl cellulose, and methyl cellulose.

According to another embodiment, the neutralizing agent may be at least one selected from the group consisting of triethylamine (TEA), sodium hydroxide (NaOH), potassium hydroxide (KOH), and cationic metals.

According to another embodiment, the surfactant may be at least one selected from the group consisting of lecithin, polysorbate, sorbitan stearate, sorbitan sesquioleate, polyoxyethylene phytosterol, glyceryl monostearate, hydrogenated soybean phospholipid, PEG-10 dimethicone, cetyl PEG/PPG-10/1 dimethicone, polyoxyethylene methylpolysiloxane copolymer, poly(oxyethyleneoxypropylene)methyl polysiloxane copolymer, and polyoxypropylene methylpolysiloxane copolymer. copolymer).

According to another embodiment, the mixed emulsion composition can be a cosmetic composition. Specifically, the cosmetic composition can be at least one of the following formulations: oil-in-water (O/W) type, water-in-oil (W/O) type, water-in-oil-in-water (W/O/W) type, or oil-in-water-in-oil (O/W/O) type.

The cosmetic composition may be a water-in-oil (O/W) formulation containing an anisotropic amphoteric powder, with the weight ratio of the oil phase to the aqueous phase being 0.1-15:5-60:10-80. In one variation, the cosmetic composition may be a water-in-oil (O/W) formulation containing an anisotropic amphoteric powder, with the weight ratio of the oil phase to the aqueous phase being 0.1-5:15-40:50-80. In another variation, the cosmetic composition may be an oil-in-water (W/O) formulation containing anisotropic amphoteric powder, with the weight ratio of the oil phase to the aqueous phase being 1-15:50-80:10-30. The oil phase may include at least one selected from the group consisting of liquid oils and fats, solid oils and fats, waxes, hydrocarbon oils, higher fatty acids, higher alcohols, synthetic ester oils, and silicone oils.

According to another embodiment, the amphoteric anisotropic powder can be added to the aqueous phase to provide a cosmetic composition.

On the other hand, a method for preparing an anisotropic amphoteric powder is provided, comprising: (1) stirring a first monomer and a polymerization initiator to form a core of a first polymer sphere; (2) stirring the formed core of the first polymer sphere together with the first monomer, the polymerization initiator, and a monomer containing a functional group to form a first polymer sphere having a core-shell structure; (3) stirring the formed first polymer sphere having a core-shell structure with a second monomer and a polymerization initiator to obtain an anisotropic powder, wherein second polymer spheres are also formed; and (4) introducing a hydrophilic functional group into the obtained anisotropic powder.

In steps (1), (2), and (3), the stirring may be rotary stirring. Because uniform mechanical mixing needs to be combined with chemical modification to produce uniform particles, rotary stirring is preferred. Rotary stirring can be performed in a cylindrical reactor, but is not limited thereto.

Here, the internal design of the reactor significantly affects the formation of the powder. The size and position of the baffles of the cylindrical reactor, as well as the distance from the impeller, have a significant impact on the uniformity of particle formation. Preferably, the spacing between the internal blades and the impeller blades is minimized to make the convection and its intensity uniform, and the powdered reaction mixture is introduced below the level of the blade length while the impeller is maintained at a high rotation speed. The rotation speed can be 200 rpm or higher, and the ratio of the diameter to the height of the reactor can be 1-3:1-5. Specifically, the reactor can have a diameter of 10-30 cm and a height of 10-50 cm. The size of the reactor can vary in proportion to its reaction capacity. In addition, the cylindrical reactor can be made of ceramic, glass or the like. Stirring is preferably carried out at a temperature of 50-90°C.

Simple mixing in a cylindrical rotating reactor produces uniform particles with low energy consumption and maximizes reaction efficiency, making it suitable for large-scale production. Conventional tumbling methods involve rotating the reactor itself, causing the entire reactor to tilt at a certain angle and rotate at high speeds. This requires high energy consumption and limits reactor size. Due to these limitations on reactor size, the output is limited to small quantities ranging from tens of milligrams to several grams. Therefore, conventional tumbling methods are not suitable for large-scale production.

According to an embodiment, the first monomer and the second monomer may be the same or different, and may be, in particular, a vinyl monomer. In addition, the first monomer added in step (2) may be the same as the first monomer used in step (1), and the initiators used in each step may be the same or different.

According to another embodiment, the vinyl monomer may be a vinyl aromatic monomer, which is a substituted or unsubstituted styrene, such as at least one selected from styrene, alpha-methylstyrene, alpha-ethylstyrene, and para-methylstyrene.

According to another embodiment, the polymerization initiator may be a free radical polymerization initiator. Specifically, the polymerization initiator may be at least one selected from peroxide-based and azo-based initiators. In addition, ammonium persulfate, sodium persulfate, or potassium persulfate may be used. The peroxide-based free radical polymerization initiator may be at least one selected from the group consisting of benzoyl peroxide, lauryl peroxide, cumene hydroperoxide, methylethyl ketone peroxide, t-butyl hydroperoxide, o-chlorobenzoyl peroxide, o-methoxybenzoyl peroxide, t-butylperoxy-2-ethylhexanoate, and t-butylperoxy isobutyrate. The azo-based free radical polymerization initiator may be at least one selected from 2,2-diisobutyronitrile (2,2-azobisisobutyronitrile), 2,2'-azobis(2-methylisobutyronitrile) and 2,2'-azobis(2,4-dimethylvaleronitrile).

According to another embodiment, in step (1), the first monomer and the polymerization initiator may be mixed at a weight ratio of 100-250:1.

In one variation, in step (1), a stabilizer is added together with the first monomer and the polymerization initiator, and the first monomer, the polymerization initiator, and the stabilizer can be mixed in a weight ratio of 100-250:1:0.001-5. The size and shape of the powder are determined by controlling the size of the first polymer spheres in step (1), and the size of the first polymer spheres can be controlled by the ratio of the first monomer, the initiator, and the stabilizer. In addition, it is possible to increase the uniformity of the anisotropic powder by mixing the first monomer, the polymerization initiator, and the stabilizer in the above-defined ratio.

According to one embodiment, the stabilizer can be an ionic vinyl monomer, specifically sodium 4-vinylbenzene sulfonate. The stabilizer prevents particle expansion and allows the powder surface to be positively or negatively charged, thereby preventing particle coalescence (binding) due to static electricity.

When the size of the amphoteric powder is 200-250 nm, it can be obtained from first polymer spheres in which the ratio of the first monomer, initiator and stabilizer is 110-130:1:2-4, preferably 115-125:1:2-4, and most preferably 120:1:3.

In addition, when the size of the amphoteric powder is 400-450 nm, it can be obtained from the first polymer spheres, in which the ratio of the first monomer, initiator and stabilizer is 225-240:1:1-3, preferably 230-235:1:1-3, and most preferably 235:1:2.

Furthermore, when the size of the amphoteric powder is 1100-1500 nm, it can be obtained from a first polymer sphere, which is prepared by reacting a first monomer, an initiator and a stabilizer in a ratio of 110-130:1:0, preferably 115-125:1:0, and more preferably 120:1:0.

In addition, amphoteric powders having an asymmetric snowman shape can be obtained from first polymer spheres, which are prepared from a first monomer, an initiator, and a stabilizer in a ratio of 100-140:1:8-12, preferably 110-130:1:9-11, and more preferably 120:1:10.

Furthermore, amphoteric powders having an asymmetric reverse snowman shape can also be obtained from first polymer spheres, wherein the ratio of the first monomer, initiator and stabilizer is 100-140:1:1-5, preferably 110-130:1:2-4, and more preferably 120:1:3.

According to another embodiment, the functional group-containing monomer in step (2) can be a siloxane-containing compound. Specifically, it can be a siloxane-containing (meth)acrylate monomer, more specifically, it can be at least one selected from the group consisting of 3-(trimethoxysilyl)propyl acrylate, 3-(trimethoxysilyl)propyl methacrylate, vinyltriethoxysilane, and vinyltriethoxysilane.

According to another embodiment, in step (2), the first monomer, the polymerization initiator, and the functional group-containing monomer can be mixed in a weight ratio of 80-98:0.2-0.8:2-20. In a variation, the first monomer, the polymerization initiator, and the functional group-containing monomer can be mixed in a weight ratio of 160-200:1:6-40. The coating degree can be controlled according to the reaction ratio, and the coating degree determines the shape of the amphoteric anisotropic powder. When the first monomer, the polymerization initiator, and the functional group-containing monomer use the ratio defined above, the coating thickness will increase by about 10-30%, specifically about 20%, compared to the initial thickness. In this case, the powder formation will proceed smoothly without the following problems: excessively thick coating causing powder formation failure, or excessively thin coating causing multi-directional powder molding. In addition, the uniformity of the anisotropic powder can be improved within the above-mentioned weight ratio.

According to yet another embodiment, in step (3), the second monomer and the polymerization initiator may be mixed in a weight ratio of 200-250:1.

In one variation, in step (3), a stabilizer may be added together with the second monomer and polymerization initiator, such that the second monomer, polymerization initiator, and stabilizer are mixed in a weight ratio of 200-250:1:0.001-5. Specific examples of the stabilizer are the same as those described above. Within the above weight ratio, the stabilizer can increase the uniformity of the anisotropic powder.

According to another embodiment, in step (3), the second monomer can be mixed with the first polymer sphere in a weight ratio of 40-300:100. Specifically, when the content of the second monomer is 40-100% by weight of the first polymer sphere, an asymmetric snowman-shaped powder is obtained. When the content of the second monomer is 100-150% by weight or 110-150% by weight of the first polymer sphere, a symmetrical powder is obtained. In addition, when the content of the second monomer is 150-300% or 160-300% by weight of the first polymer sphere, an asymmetric reverse snowman-shaped powder is obtained. The uniformity of the anisotropic powder can be increased within the above-mentioned weight ratio.

According to another embodiment, in step (4), the hydrophilic functional group may be introduced by using a silane coupling agent and a reaction modifier, but the invention is not limited thereto.

According to another embodiment, the silane coupling agent may be at least one selected from the group consisting of (3-aminopropyl)trimethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine, N-[3-(trimethoxysilyl)propyl]ethylenediamine ammonium chloride, The silane coupling agent may be 1-[3-(trimethoxysilyl)propyl]urea, 1-[3-(trimethoxysilyl)propyloxy]-1,2-propanediol ...

According to another embodiment, the reaction modifier may be ammonium hydroxide.

According to the related art, many attempts have been made to increase the surface activity of spherical powder particles for Pickering by imparting surface active properties to amphoteric particles. This can be exemplified by Janus spherical particles. However, such particles are geometrically limited and have problems with large-scale production and, therefore, cannot be used in practice. In contrast, the preparation method for the amphoteric anisotropic powder disclosed in the present invention does not use a cross-linking agent and therefore does not cause agglomeration and provides high yield and uniformity. In addition, the method disclosed herein uses a simple stirring process, which is more suitable for mass production than the tumbling process. In particular, the method disclosed herein has the advantage that it allows for the large-scale production of tens of grams and tens of kilograms of nano-sized particles, which are 300 nanometers or less in size.

[Example]

The present invention will now be described more fully hereinafter with reference to exemplary embodiments illustrated in the accompanying drawings. However, the present invention may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein.

[Preparation Example 1] Preparation of polystyrene (PS) first polymer spheres

Styrene as a monomer, sodium 4-vinylbenzene sulfonate as a stabilizer, and azobisisobutyronitrile (AIBN) as an initiator were mixed in an aqueous phase and reacted at 75°C for 8 hours. The reaction was carried out in a glass cylindrical reactor with a diameter of 11 cm and a height of 17 cm, with the mixture stirred at 200 rpm.

[Preparation Example 2] Preparation of coated first polymer spheres having a core-shell (CS) structure

The polystyrene (PS) first polymer spherical particles obtained above were mixed with styrene as a monomer and 3-(trimethoxysilyl)propyl acrylate (TMSPA) and azobisisobutyronitrile (AIBN) as initiators, and reacted. The reaction was carried out by stirring the reaction mixture in a cylindrical reactor.

[Preparation Example 3] Preparation of anisotropic powder

The polystyrene core-shell aqueous dispersion (PC-CS) obtained above was mixed with styrene as a monomer, sodium 4-vinylbenzenesulfonate as a stabilizer, and azobisisobutyronitrile (AIBN) as an initiator. The reaction mixture was heated to 75°C to initiate a reaction. The reaction was carried out by stirring the reaction mixture in a cylindrical reactor. In this manner, an anisotropic powder with a symmetrical shape was obtained.

[Preparation Example 4] Hydrophilization

The aqueous dispersion of the anisotropic powder obtained above was mixed with N-[3-(trimethoxysilyl)propyl]ethylenediamine (a silane coupling agent) and ammonium hydroxide (a reaction modifier) to introduce a hydrophilic functional group. The reaction was carried out by stirring the reaction mixture in a cylindrical reactor.

[Example 1]

The amphoteric anisotropic powder obtained from the above preparation example was used to prepare a microemulsion composition having the composition shown in Table 1 below. In a separate container, a nanoemulsion composition was prepared using a conventional surfactant according to Table 2 below. The microemulsion composition and the nanoemulsion composition were then mixed in a weight ratio of 9:1 to obtain the composition of Example 1.

[Table 1]

Element Quantity (weight %) water to 100 Amphoteric anisotropic powder 2.5 Preservative 1 (Phenoxyethanol) 0.3 Preservative 2 (Ethylhexylglycerin) 0.05 Moisturizer (Butylene Glycerol) 8 Oil (Hydrogenated polydecane) 10

[Table 2]

[Test Example 1] Observation of changes in emulsified particles at high temperatures

The composition of Example 1 was sampled and the emulsified particles were observed under a microscope. The composition was then stored at a high temperature of 45°C for 5 days, and changes in the particles were observed.

Observations have shown that by using amphoteric anisotropic powders and conventional surfactants to form larger emulsified particles (tens of microns) and smaller emulsified particles (a few nanometers), and then simply mixing the particles through physical stirring, a mixed emulsion composition can be produced. This mixed emulsion composition can achieve a variety of user experiences depending on the mixing ratio of the emulsified components.

Figure 1 shows microscopic images of mixed emulsion compositions obtained by the individual emulsion mixing methods according to the examples, wherein (a) shows a preparation obtained from emulsified particles using anisotropic powder (size: approximately tens of microns) and nanoemulsified particles using a general surfactant (size: approximately 200 nm), a picture of which is obtained immediately after preparation, (b) and (c) show the emulsion particle size images after the preparation was stored at 45°C for 2 weeks and 4 weeks, respectively, and (d) shows the fluorescence imaging results of the nanoemulsion in the sample. As can be seen from Figure 1, even after the mixed emulsion composition was stored at 45°C for 4 weeks, there was no change in its particle size or aggregation between different particles. In addition, no separation, precipitation, or gelatinization was observed, and no Oswald ripening occurred. The two different types of particles each existed stably and coexisted independently of each other.

[Test Example 2] Observation of particle distribution of emulsified particles

The emulsified particle size of the mixed emulsion composition obtained in Example 1 was measured using a Zetasizer Nano (Brand: Malvern). The particle size distributions were measured immediately after preparation and after 4 weeks at 45° C., as shown in FIG2 .

In Figure 2, (a) shows an average particle size distribution of approximately 200 nm immediately after preparation, while (b) shows an average particle size distribution of approximately 190 nm after four weeks. Therefore, it can be seen that no significant difference in the distribution was observed, and the hybrid emulsion remained stable over time.

[Test Example 3] Evaluation of composition stability over time

The stability of the mixed emulsion composition obtained in Example 1 was measured by maintaining the composition at -15°C to 60°C for 18 weeks. The formulation remained stable at various temperatures without creaming or oil separation, indicating that the composition in Example 1 was highly stable over time and at various temperatures.

Figure 3 is a graph showing the viscosity change of the mixed emulsion composition of Example 1 after being maintained at 30°C for 18 weeks. Viscosity was measured using a viscometer (Model: LVDV-II+PRO, Brookfield, USA). As shown in Figure 3 , no significant change in viscosity was observed even after prolonged exposure to 30°C, indicating that the mixed emulsion composition exhibits high formulation stability.

As can be seen from the foregoing description, the hybrid emulsion composition disclosed herein remains stable even for extended periods within a temperature range, with each microemulsified particle and nanoemulsified particle independently maintaining its particle size and stability. This is believed to be because emulsions using anisotropic powders have a different emulsion system than conventional emulsions, resulting in minimal interfacial interaction between the two types of emulsified particles. Furthermore, in emulsions using anisotropic powders, the emulsified particles are firmly retained at the emulsion interface, preventing particle aggregation.

While exemplary embodiments have been shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit of the invention and the scope thereof as set forth in the appended claims.

Therefore, it is intended that all embodiments that fall within the spirit and scope of the appended claims be encompassed within the scope of the present invention.

Claims (6)

1. An emulsion composition having different emulsion particle sizes, said emulsion composition comprising large emulsion particles of 1 micrometer to 100 micrometers and nano-emulsion particles of 100 nanometers to 900 nanometers, The large emulsified particles mentioned above include amphoteric anisotropic powders; The amphoteric anisotropic powder comprises a first hydrophilic polymer sphere and a second hydrophobic polymer sphere. The first hydrophilic polymer sphere and the second hydrophobic polymer sphere are bonded together in a structure in which at least one polymer sphere is partially infiltrated into the other polymer sphere; The first hydrophilic polymer sphere has a core-shell structure, and its shell has functional groups; The core of the second hydrophobic polymer sphere and the first hydrophilic polymer sphere comprises a vinyl polymer, while the shell of the first hydrophilic polymer sphere comprises a copolymer of vinyl monomers and functional groups. The vinyl polymer comprises polystyrene, and the functional group is a siloxane; and The preparation method of the aforementioned amphoteric anisotropic powder does not use a crosslinking agent. The nanoemulsion particles include a surfactant selected from at least one of the following: lecithin, hydrogenated lecithin, polysorbate, sorbitan stearate, sorbitan sesquioleate, polyoxyethylene phytosterol ether, glyceryl monostearate, and hydrogenated soybean lecithin. The macroemulsified particles and the nanoemulsified particles exist in a ratio of 7-9:3-1. The emulsion composition comprises 0.1-15 wt% of the amphoteric anisotropic powder in the total weight of the emulsion composition. 2. The emulsion composition of claim 1, wherein the shell of the first hydrophilic polymer sphere further comprises hydrophilic functional groups introduced therein. 3. The emulsion composition of claim 2, wherein the hydrophilic functional group is selected from at least one of the following groups: carboxylic acid group, sulfone group, phosphate group, amino group, alkoxy group, ester group, acetate group, polyethylene glycol group, and hydroxyl group. 4. The emulsion composition of claim 1, wherein the amphoteric anisotropic powder has a symmetrical shape, an asymmetrical snowman shape, or an asymmetrical reverse snowman shape, the shape being determined by the location at which the first hydrophilic polymer spheres and the second hydrophobic polymer spheres are bonded to each other. 5. The emulsion composition according to claim 1, wherein the particle size of the amphoteric anisotropic powder is 100 nm to 1500 nm. 6. A method for preparing an emulsion composition as described in any one of claims 1 to 5, comprising: An emulsion composition comprising an amphoteric anisotropic powder for preparing large emulsion particles with a particle size of 1 micrometer to 100 micrometers and an emulsion composition comprising a surfactant for preparing nano-emulsion particles with a particle size of 100 nanometers to 900 nanometers are respectively formed, and the emulsion compositions are mixed together.