Microcapsules

Abstract

The present invention pertains to a microcapsule having a shell and a core, the shell containing an inorganic substance as a constituent component, the core containing one or more organic compounds inside the shell, the organic compounds containing the following component (A), component (B1), and component (B2), the content ratio of the component (B1) to the component (A) being 0.01-7 mass%, and the content ratio of the component (B2) to the component (A) being 0.01-7 mass%. The content ratio of the component (B2) relative to the component (A) is from 1% by mass to 10% by mass (inclusive); component (B1): one or more substances selected from the group consisting of a higher aliphatic alcohol having 6 or more carbon atoms, a higher fatty acid having 6 or more carbon atoms, a monoalkyl glyceryl ether having an alkyl group having 6 or more carbon atoms, and an amide compound having an alkyl group having 8 or more carbon atoms, and component (B2): a fatty acid ester having 6 or more carbon atoms in total, excluding component (A). The component (A) is excluded.

Description

[0001] (This application is a divisional application of patent application No. 202080108202.1, filed on December 28, 2020, entitled “Microcapsules”.) Technical Field

[0002] This invention relates to microcapsules and methods for manufacturing microcapsules. Background Technology

[0003] Microcapsules containing fragrances or bioactive agents have been developed and utilized in a wide range of industries, including cosmetics, pharmaceuticals, household goods, and printing. For example, amino plastic resins such as melamine resin or polyurea / polyurethane resin are used as the shell of these microcapsules. However, microcapsules cannot avoid being released into the environment, and in recent years, they have become a source of concern as microplastics. Therefore, there is a desire to develop a more environmentally friendly microcapsule to replace amino plastic resins.

[0004] Among them, silica microcapsules (hereinafter also referred to as "silica capsules") with a shell composed of silica have attracted much attention as a material that can be expected to be environmentally friendly.

[0005] Silica capsules are typically obtained by forming silica on the surface of emulsion droplets using a sol-gel reaction. However, because silica capsules are extremely small particles, their shells are also very thin and brittle. Therefore, sometimes due to shell disintegration, the encapsulated components of the silica capsule diffuse through the micropores present in the shell, resulting in the release of some of these components into the external environment. Consequently, research continues on various silica capsules utilizing the sol-gel reaction.

[0006] For example, Japanese Patent Application Publication No. 2013-255915 (Patent Document 1) discloses a method for manufacturing microcapsules, which have a core material containing active ingredients such as sunscreen. The method for manufacturing microcapsules includes the following steps: emulsifying an oily phase composed of a water-insoluble precursor and a core material in an aqueous phase composed of an aqueous solution having a specified pH under appropriate shear force and temperature conditions, thereby producing an oil-in-water droplet emulsion.

[0007] In Japanese Patent Application Publication No. 2015-128762 (Patent Document 2), the object is to provide a method for manufacturing microcapsules that can retain effective ingredients such as fragrances, i.e., functional oils, for a long time. The method describes the following: In the method for manufacturing microcapsules having a core composed of functional oils such as fragrances, a first shell enclosing the core, and a second shell enclosing the first shell, a first-stage sol-gel reaction is carried out in an aqueous phase containing a surfactant, with an organic phase containing functional oils and tetraalkoxysilane being emulsified. Then, tetraalkoxysilane is added, and a second-stage sol-gel reaction is carried out while maintaining a pH lower than that of the first-stage sol-gel reaction, thereby obtaining a silica capsule with high shell density. Summary of the Invention

[0008] This invention provides a microcapsule having a shell and a core, wherein the shell contains inorganic matter as a constituent component, and the core contains one or more organic compounds inside the shell.

[0009] The organic compound contains the following components (A) and (B1).

[0010] Ingredient (A): Functional oil,

[0011] Ingredient (B1): Selected from one or more of the following: higher monohydric alcohols with 6 or more carbon atoms, higher aliphatic alcohols, higher fatty acids with 6 or more carbon atoms, monoalkyl glycerol ethers having alkyl groups with 6 or more carbon atoms, and amide compounds having alkyl groups with 8 or more carbon atoms (excluding ingredient (A)). Detailed Implementation

[0012] It has been confirmed that in the technologies of Patent Documents 1 and 2, sometimes due to the different oils contained therein, it is not possible to obtain a target silica capsule that can suppress the leakage of nuclear components, and it is not possible to maintain functional oils such as fragrances for a long period of time.

[0013] Furthermore, microcapsules are required to be resistant to disintegration and possess excellent stability during the distribution process. The physical strength of microcapsules also depends on their particle size; from the perspective of improving the physical strength of microcapsules, excellent control over the particle size of microcapsules with smaller diameters is also required.

[0014] This invention relates to a microcapsule and a method for manufacturing the microcapsule. The microcapsules of this invention can retain the encapsulated fragrance and other functional oils for a long period of time, and also have excellent particle size control.

[0015] The inventors have discovered that by including a functional oil and a component having specific hydrocarbon and polar groups inside a shell containing inorganic matter as a constituent, it is possible to reduce the particle size of microcapsules and improve the retention of the functional oil.

[0016] That is, the present invention relates to [1] and [2] below.

[0017] [1] A microcapsule having a shell and a core, the shell containing inorganic matter as a constituent component, and the core containing one or more organic compounds inside the shell.

[0018] The organic compound contains the following components (A) and (B1).

[0019] Ingredient (A): Functional oil,

[0020] Ingredient (B1): Selected from one or more of the following: higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having alkyl groups having 6 or more carbon atoms, and amide compounds having alkyl groups having 8 or more carbon atoms (excluding ingredient (A)).

[0021] [2] A method for manufacturing microcapsules, wherein the microcapsules have a shell and a core, the shell containing inorganic matter as a constituent component, and the core containing one or more organic compounds inside the shell.

[0022] The method for manufacturing the aforementioned microcapsules includes the following steps: emulsifying an oil-water mixture containing oil phase components and aqueous phase components, and then subjecting it to a sol-gel reaction to form microcapsules.

[0023] The above oil phase composition contains the following components (A), (B1) and (C).

[0024] Ingredient (A): Functional oil,

[0025] Ingredient (B1): Selected from one or more of the following: higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having alkyl groups having 6 or more carbon atoms, and amide compounds having alkyl groups having 8 or more carbon atoms (excluding ingredient (A)).

[0026] Ingredient (C): Shell precursor.

[0027] According to the present invention, a microcapsule and a method for manufacturing the microcapsule are provided. The microcapsule of the present invention can retain the encapsulated functional oils such as fragrances for a long period of time, and the particle size control is also excellent.

[0028] [Microcapsules]

[0029] The microcapsule of the present invention is a microcapsule having a shell containing inorganic matter as a constituent component and a core containing one or more organic compounds inside the shell, the organic compounds comprising the following components (A) and (B1).

[0030] Ingredient (A): Functional oil,

[0031] Ingredient (B1): Selected from one or more of the following: higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having alkyl groups having 6 or more carbon atoms, and amide compounds having alkyl groups having 8 or more carbon atoms (excluding ingredient (A)).

[0032] It should be noted that, in this specification, the long-term retention of component (A) encapsulated in microcapsules is also referred to as "long-term retention".

[0033] Furthermore, in this invention, "sol-gel reaction" refers to a reaction in which a shell precursor, through hydrolysis and condensation reactions, forms the inorganic components of the shell in a sol and gel state. Here, "shell precursor" refers to a substance capable of forming the shell of a microcapsule. For example, in a silica capsule, a tetraalkoxysilane, as a shell precursor, undergoes hydrolysis, and a silanol compound generates a siloxane oligomer through dehydration condensation and dealcoholization condensation reactions, which further undergo dehydration condensation reactions to form silica.

[0034] According to the present invention, a microcapsule can be provided that retains functional oils such as fragrances for a long period of time, and also exhibits excellent control over particle size. The reason for this is not yet clear, but it is believed to be as follows.

[0035] In this invention, the organic compound contained in the core, in addition to containing a functional oil as component (A), also contains one or more selected from higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having alkyl groups having 6 or more carbon atoms, and amide compounds having alkyl groups having 8 or more carbon atoms as component (B1). Component (B1) has long-chain aliphatic hydrocarbon groups and polar groups, and is highly hydrophobic. Therefore, it is believed to have the following effect: when manufacturing microcapsules, the oil phase component of the oil-water mixture used to prepare the emulsion for the sol-gel reaction contains component (B1), thereby, the polar groups of component (B1) are oriented towards the interface with the aqueous phase, stably and finely forming emulsion droplets that form the mold for microcapsules. Moreover, because component (B1) is densely oriented towards the interface with the aqueous phase, the shell itself has a robust structure. It is speculated that the result is the ability to obtain microcapsules with dense and robust shells, which inhibits the leakage of functional oils, improves long-term retention, and further enhances the controllability of silica capsule particle size.

[0036] <Nuclear>

[0037] (ingredient (A))

[0038] The organic compound contained in the core of the microcapsule of the present invention includes a functional oil as component (A).

[0039] "Functional oil" in ingredient (A) is an oil that, depending on its use or purpose, demonstrates an effect useful to its use or purpose.

[0040] Component (A) is preferably selected from one or more of fragrances, fragrance precursors, humectants, antioxidants, antibacterial agents, fertilizers, fibers, skin, and hair surface modifiers, cooling agents, dyes, pigments, silicones, and oil-soluble polymers; more preferably selected from one or more of fragrances, fragrance precursors, humectants, antioxidants, antibacterial agents, fertilizers, and surface modifiers; even more preferably selected from one or more of fragrances, fragrance precursors, humectants, and antioxidants; even more preferably selected from one or more of fragrances, fragrance precursors, and humectants; and even more preferably selected from one or more of fragrances and fragrance precursors.

[0041] Regarding ingredient (A), one or more can be used alone.

[0042] Examples of fragrance precursors include compounds that release fragrance components by reacting with water and compounds that release fragrance components by reacting with light.

[0043] Examples of compounds that release fragrance components upon reaction with water include: silicate ester compounds having alkoxy groups derived from fragrance alcohols; fatty acid ester compounds having alkoxy groups derived from fragrance alcohols; acetal or hemiacetal compounds obtained by reacting a carbonyl group derived from a fragrance aldehyde or ketone with an alcohol compound; Schiff base compounds obtained by reacting a carbonyl group derived from a fragrance aldehyde or ketone with a primary amine compound; and hemiamine acetal or hydrazone compounds obtained by reacting a carbonyl group derived from a fragrance aldehyde or ketone with a hydrazine compound.

[0044] Examples of compounds that release fragrance components upon photoreaction include: 2-nitrobenzyl ether compounds having an alkoxy group derived from a fragrance alcohol; α-keto ester compounds having a carbonyl group derived from a fragrance aldehyde or ketone; and coumarate ester compounds having an alkoxy group derived from a fragrance alcohol. These fragrance precursors can, for example, be used as polymers of the reaction product of a portion of the carboxyl group of polyacrylic acid and a fragrance alcohol.

[0045] From the perspective of improving the long-term retention of functional oils and improving the control of microcapsule particle size, component (A) preferably has appropriate hydrophobicity.

[0046] As an indicator of the hydrophilicity or hydrophobicity of the aforementioned functional oils, the commonly used logarithm "LogP" of the partition coefficient P (octanol / water) between n-octanol and water, i.e., the cLogP value, can be used. The cLogP value is calculated using the method described in A. Leo Comprehensive Medicinal Chemistry, Vol.4, C. Hansch, PG Sammens, JB Taylor and CARamsden, Eds., P.295, Pergamon Press, 1990, and is calculated by the program CLOGP v4.01.

[0047] When component (A) is composed of multiple constituent components, the cLogP value of component (A) can be obtained by multiplying the cLogP value of each constituent component by the volume ratio of each constituent component and summing them.

[0048] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the cLogP value of component (A) is preferably 1 or more, more preferably 2 or more, even more preferably 3 or more, and preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less.

[0049] (Ingredient (B1))

[0050] From the viewpoints of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the organic compound contained in the core of the microcapsules of the present invention comprises one or more selected from higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having alkyl groups having 6 or more carbon atoms, and amide compounds having alkyl groups having 8 or more carbon atoms as component (B1). Component (B1) does not include component (A).

[0051] It should be noted that, regarding ingredient (B1), one or more can be used alone.

[0052] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the molecular weight of component (B1) is preferably 500 or less, more preferably 450 or less, even more preferably 400 or less, even more preferably 350 or less, and preferably 150 or more.

[0053] [Higher aliphatic alcohols with 6 or more carbon atoms]

[0054] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the carbon number of the above-mentioned higher aliphatic alcohols is preferably 8 or more, more preferably 10 or more, even more preferably 12 or more, even more preferably 14 or more, and preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less.

[0055] The aforementioned higher aliphatic alcohols are preferably straight-chain or branched higher aliphatic alcohols, and more preferably straight-chain higher aliphatic primary alcohols.

[0056] From the viewpoint of ease of handling, the aforementioned higher aliphatic alcohols are preferably components that are solid at room temperature and pressure (e.g., with a melting point of 30°C or higher). The melting point of the aforementioned higher aliphatic alcohols is preferably 30°C or higher, more preferably 35°C or higher, even more preferably 40°C or higher, and even more preferably 45°C or higher.

[0057] Examples of higher aliphatic primary alcohols include, for example, 2-ethylhexanol, lauryl alcohol, myristol, cetyl alcohol, stearyl alcohol, behenyl alcohol, and oleyl alcohol. Preferably, it is selected from one or more of 2-ethylhexanol, lauryl alcohol, myristol, cetyl alcohol, and stearyl alcohol; more preferably, it is selected from one or more of cetyl alcohol and stearyl alcohol; and even more preferably, it is cetyl alcohol.

[0058] [Higher fatty acids with 6 or more carbon atoms]

[0059] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the carbon number of the aforementioned higher fatty acids is preferably 8 or more, more preferably 10 or more, even more preferably 12 or more, even more preferably 14 or more, even more preferably 16 or more, and preferably 26 or less, more preferably 22 or less, and even more preferably 20 or less.

[0060] Examples of the aforementioned higher fatty acids include, for example, 2-ethylhexanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, linoleic acid, linolenic acid, lanonic acid, and isostearic acid. Among these, branched-chain saturated fatty acids are preferred, and isostearic acid is more preferred.

[0061] [Monoalkyl glycerol ethers having an alkyl group having 8 or more carbon atoms]

[0062] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the number of carbon atoms in the alkyl group of the above-mentioned monoalkyl glycerol ether is preferably 10 or more, more preferably 12 or more, even more preferably 14 or more, even more preferably 16 or more, and preferably 24 or less, more preferably 22 or less, and even more preferably 22 or less.

[0063] Examples of the aforementioned monoalkyl glycerol ethers include, for example, mono-2-ethylhexylglycerol ether, monodecylglycerol ether, monolaurylglycerol ether, monomyristylglycerol ether, monohexadecylglycerol ether, monostearylglycerol ether, and monobenzylglycerol ether. Preferably, one or more of monohexadecylglycerol ether, monostearylglycerol ether, and monobenzylglycerol ether are selected, and more preferably, monostearylglycerol ether. It should be noted that the aforementioned monoalkyl glycerol ethers are typically α-forms.

[0064] [Amide compounds having alkyl groups having 8 or more carbon atoms]

[0065] The alkyl group of the above-mentioned amide compound preferably has 10 or more carbon atoms, more preferably 12 or more, even more preferably 14 or more, and preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less.

[0066] As the aforementioned amide compounds, amide compounds having alkyl groups derived from saturated or unsaturated fatty acids are preferred. Specifically, examples include laurylamide, myristamide, palmitamide, stearamide, and oleamide.

[0067] From the viewpoint of improving the controllability of microcapsule particle size, component (B1) is preferably selected from one or more of higher fatty acids with 6 or more carbon atoms and higher aliphatic alcohols with 6 or more carbon atoms, and more preferably higher fatty acids with 6 or more carbon atoms.

[0068] From the viewpoint of improving the long-term retention of functional oils, component (B1) is preferably selected from one or more of alkyl glycerol ethers having an alkyl group having 8 or more carbon atoms and higher fatty acids having 6 or more carbon atoms, and more preferably alkyl glycerol ethers having an alkyl group having 8 or more carbon atoms.

[0069] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the content ratio of component (B1) in the microcapsules of the present invention relative to component (A) is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less, and even more preferably 4% by mass or less.

[0070] It should be noted that the content ratio of component (B1) relative to component (A) is the content ratio when component (A) in the microcapsule is set to 100% by mass.

[0071] (Ingredient (B2))

[0072] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the organic compound contained in the core of the microcapsules of the present invention preferably further includes the following component (B2).

[0073] Component (B2): Selected from one or more fatty acid esters with a total carbon number of 6 or more and higher alkanes with a carbon number of 6 or more.

[0074] Component (B2) does not include component (A).

[0075] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the cLogP value of component (B2) is preferably 4 or more, more preferably 5 or more, further preferably 6 or more, even more preferably 7 or more, and preferably 10 or less, more preferably 9 or less.

[0076] [Fatty acid esters with a total number of 6 or more carbon atoms]

[0077] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the total number of carbon atoms in the above-mentioned fatty acid esters is 6 or more, preferably 10 or more, more preferably 14 or more, even more preferably 18 or more, and more preferably 50 or less.

[0078] Examples of the aforementioned fatty acid esters include: fatty acid monoesters obtained from fatty acids and monohydric alcohols, fatty acid diesters obtained from fatty acids and dihydric alcohols, dicarboxylic acid diesters obtained from dicarboxylic acids and monohydric alcohols, tricarboxylic acid triesters obtained from tricarboxylic acids and monohydric alcohols, and glycerol fatty acid triesters. Among these, fatty acid monoesters are preferred from the viewpoints of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size.

[0079] The aforementioned fatty acid monoesters are preferably derived from fatty acids having 8 to 22 carbon atoms and monohydric alcohols having 1 to 24 carbon atoms.

[0080] Examples of fatty acids that constitute the above-mentioned fatty acid monoesters include saturated or unsaturated fatty acids with 8 to 22 carbon atoms, such as 2-ethylhexanoic acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, palmitoleic acid, heptadecanoic acid, stearic acid, oleic acid, linoleic acid, erucic acid, arachidic acid, behenic acid, etc.

[0081] Examples of monohydric alcohols constituting the aforementioned fatty acid monoesters include aliphatic monohydric alcohols with 1 to 24 carbon atoms, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, neopentanol, hexanol, heptanol, octanol, 2-ethylhexanol, nonanol, isononol, decanol, isodecanol, dodecanol, lauryl alcohol, tridecanol, myristol, pentadecanol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, behenol, and 2-octyldodecanol.

[0082] Examples of the aforementioned fatty acid monoesters include cetyl 2-ethylhexanoate, butyl stearate, isopropyl myristate, hexadecyl myristate, 2-octyl dodecyl myristate, isopropyl palmitate, hexadecyl palmitate, and 2-ethylhexyl stearate. Isopropyl palmitate is preferred.

[0083] [Higher alkanes with 6 or more carbon atoms]

[0084] The number of carbon atoms in the aforementioned higher alkanes is preferably 6 or more and 32 or less, more preferably 10 or more and 32 or less.

[0085] Examples of the aforementioned higher alkanes include those with 6 to 32 saturated or unsaturated carbon atoms in their straight or branched chains, such as decane, undecane, dodecane, isododecane, tridecane, tetradecane, hexadecane, octadecane, eicosane, docosane, squalane, and squalene.

[0086] From the perspective of improving the long-term retention of functional oils and improving the control of microcapsule particle size, component (B2) is preferably a fatty acid ester with a total carbon number of 6 or more.

[0087] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the content ratio of component (B2) in the microcapsules of the present invention relative to component (A) is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, even more preferably 0.7% by mass or more, and preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less, even more preferably 4% by mass or less, and even more preferably 3% by mass or less.

[0088] It should be noted that the content ratio of component (B2) relative to component (A) is the content ratio when component (A) in the microcapsule is set to 100% by mass.

[0089] <Shell>

[0090] (Inorganic matter)

[0091] The shell of the microcapsules of the present invention contains inorganic substances as constituent components.

[0092] The aforementioned inorganic material is preferably a metal oxide containing a metallic or semi-metallic element, and more preferably an inorganic polymer formed by a sol-gel reaction using a metal alkoxide [M(OR)x] as a shell precursor. Here, M is a metallic or semi-metallic element, and R is a hydrocarbon group.

[0093] Examples of metallic or semi-metallic elements that constitute metal alkoxides include silicon, aluminum, titanium, zirconium, and zinc.

[0094] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the aforementioned inorganic material is preferably an inorganic polymer formed by a sol-gel reaction using an alkoxide of one or more metals selected from silicon, aluminum, and titanium as a shell precursor, and more preferably an alkoxysilane polymer.

[0095] From the perspective of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the above-mentioned alkoxysilane is preferably a tetraalkoxysilane.

[0096] From the same viewpoint as described above, it is preferable that the component has an alkoxy group having 1 to 4 carbon atoms, more preferably one or more selected from tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane, further preferably one or more selected from tetramethoxysilane and tetraethoxysilane, and even more preferably tetraethoxysilane.

[0097] [Method for manufacturing microcapsules]

[0098] The microcapsules of the present invention are obtained by a manufacturing method comprising the following steps: emulsifying an oil-water mixture containing an oil phase component and an aqueous phase component and subjecting it to a sol-gel reaction to form microcapsules (hereinafter also referred to as "Step I"), wherein the oil phase component contains component (A), component (B1) and component (C) as described below.

[0099] Ingredient (A): Functional oil,

[0100] Ingredient (B1): Selected from one or more of the following: higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having alkyl groups having 6 or more carbon atoms, and amide compounds having alkyl groups having 8 or more carbon atoms (excluding ingredient (A)).

[0101] Ingredient (C): Shell precursor.

[0102] <Oil-water mixture>

[0103] In the manufacturing method of the present invention, components (A) and (B1) are as described above.

[0104] It is believed that component (B1), due to its long-chain aliphatic hydrocarbon groups and polar groups, functions as an emulsifying agent in the emulsification of oil-water mixtures, enabling the rapid formation of stable and fine emulsion droplets. Therefore, it is believed that it can suppress shell damage caused by prolonged mechanical force, provide a suitable shell-forming site as a mold for microcapsules, improve the long-term retention of organic compounds, and further enhance the controllability of microcapsule particle size.

[0105] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the oil phase component of the above-mentioned oil-water mixture preferably also includes the above-mentioned component (B2).

[0106] It is believed that in this invention, component (B2) functions as a particle size stabilizer that stabilizes the particle size of the molded emulsion droplets that become microcapsules.

[0107] It is believed that component (B2) helps to suppress the instability of emulsion droplets caused by Oswald ripening of the relatively hydrophilic component, which is an oil phase component in the emulsion droplets, due to molecular diffusion into the continuous phase, i.e., the aqueous phase. This suppresses the coarsening of the emulsion droplets over time, thereby stabilizing the particle size of the emulsion droplets used as the mold for microcapsules. Therefore, it is believed that by using component (B2) in combination with component (B1), a suitable shell-forming site can be provided as the mold for microcapsules, improving the long-term retention of organic compounds and further enhancing the controllability of microcapsule particle size. From this viewpoint, as described above, the clogP value of component (B2) is preferably 4 or more, more preferably 5 or more, further preferably 6 or more, even more preferably 7 or more, and preferably 10 or less, more preferably 9 or less.

[0108] It should be noted that, in addition to functioning as an emulsifying aid, component (B1) may also function as a particle size stabilizer, stabilizing the particle size of the molded emulsion droplets that form microcapsules. From this perspective, component (B1) is preferably selected from one or more of higher fatty acids having 6 or more carbon atoms and higher aliphatic alcohols having 6 or more carbon atoms, and more preferably higher fatty acids having 6 or more carbon atoms.

[0109] Furthermore, from the viewpoint of improving the long-term retention of functional oils, the cLogP value of component (B1) is preferably 4 or more, more preferably 5 or more, even more preferably 6 or more, and preferably 10 or less, more preferably 9 or less.

[0110] From the viewpoint of improving the controllability of microcapsule particle size, the cLogP value of component (B1) is preferably 4 or more, more preferably 5 or more, even more preferably 6 or more, even more preferably 7 or more, and preferably 10 or less, more preferably 9 or less.

[0111] From the viewpoint of not hindering the movement of the shell precursor to the oil-water interface and the formation of the shell in the system, the amount of component (B2) used in the manufacturing method of the present invention is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.15% by mass or more.

[0112] It should be noted that the amount of component (B2) is the amount when the total amount of the oil-water mixture is set to 100% by mass.

[0113] (Component (C))

[0114] The oil phase component of the above oil-water mixture includes shell precursor as component (C).

[0115] As described above, component (C) is a substance capable of forming the shell of microcapsules, preferably a metal alkoxide [M(OR)x]. Here, M and R are the same as described above.

[0116] Examples of metallic or semi-metallic elements that constitute metal alkoxides include silicon, aluminum, titanium, zirconium, and zinc.

[0117] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, component (C) is preferably an alkoxide selected from one or more metals selected from silicon, aluminum and titanium, and more preferably an alkoxysilane.

[0118] From the perspective of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the above-mentioned alkoxysilane is preferably a tetraalkoxysilane.

[0119] From the same viewpoint as described above, the tetraalkoxysilane preferably has an alkoxy group having 1 to 4 carbon atoms, more preferably is selected from one or more of tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane, further preferably is selected from one or more of tetramethoxysilane and tetraethoxysilane, and even more preferably is tetraethoxysilane.

[0120] From the viewpoint of forming a shell surrounding the oil-phase emulsion droplets containing the functional oil agent, the amount of component (C) used in the manufacturing method of the present invention is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, relative to the amount of component (A). Moreover, from the viewpoint of suppressing the residue of the shell precursor inside the oil-phase droplets and effectively carrying out the conversion to the shell, it is preferably 100% by mass or less, more preferably 70% by mass or less, even more preferably 50% by mass or less, and even more preferably 30% by mass or less.

[0121] It should be noted that the amount of component (C) is the amount when the amount of component (A) is set to 100% by mass.

[0122] (Catonic surfactants)

[0123] From the viewpoint of improving the long-term retention of functional oils and improving the controllability of microcapsule particle size, the aqueous phase component of the above-mentioned oil-water mixture preferably contains a cationic surfactant.

[0124] Examples of cationic surfactants include alkylamine salts and alkyl quaternary ammonium salts. The alkyl groups of alkylamine salts and alkyl quaternary ammonium salts preferably have 6 or more carbon atoms, more preferably 8 or more, even more preferably 10 or more, even more preferably 12 or more, even more preferably 14 or more, and preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less.

[0125] Examples of alkylamine salts include laurylamine acetate and stearylamine acetate.

[0126] Examples of alkyl quaternary ammonium salts include alkyl trimethylammonium salts, dialkyl dimethylammonium salts, and alkyl benzyl dimethylammonium salts.

[0127] Examples of the above-mentioned alkyltrimethylammonium salts include: lauryltrimethylammonium chloride, hexadecyltrimethylammonium chloride, stearyltrimethylammonium chloride, and other alkyltrimethylammonium chlorides; lauryltrimethylammonium bromide, hexadecyltrimethylammonium bromide, stearyltrimethylammonium bromide, and other alkyltrimethylammonium bromide.

[0128] Examples of the above-mentioned dialkyl dimethyl ammonium salts include: dialkyl dimethyl ammonium chloride such as distearate dimethyl ammonium chloride; and dialkyl dimethyl ammonium bromide such as distearate dimethyl ammonium bromide.

[0129] Examples of alkylbenzyl dimethyl ammonium salts include alkylbenzyl dimethyl ammonium chloride and alkylbenzyl dimethyl ammonium bromide.

[0130] Regarding the aforementioned cationic surfactants, one or more can be used alone.

[0131] Among the above-mentioned components, the cationic surfactant is preferably a quaternary ammonium salt, more preferably an alkyltrimethylammonium salt having an alkyl group having 6 to 22 carbon atoms, further preferably one or more selected from lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, and hexadecyltrimethylammonium chloride, and even more preferably hexadecyltrimethylammonium chloride.

[0132] From the viewpoint of obtaining a stable emulsion, the amount of cationic surfactant used in the manufacturing method of the present invention is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, relative to the amount of component (A).

[0133] Furthermore, it is believed that when the aqueous phase component of the oil-water mixture contains a cationic surfactant, by using component (B1) in combination with this cationic surfactant, the dynamic surface tension reduction capability of the system is improved, enabling the rapid formation of stable and fine emulsion droplets. From the viewpoint of improving the dynamic surface tension reduction capability of the system, as described above, the molecular weight of component (B1) is preferably 500 or less, more preferably 450 or less, further preferably 400 or less, and even more preferably 350 or less.

[0134] From the viewpoint of manufacturing efficiency, the amount of oil phase component relative to the total amount of the oil-water mixture is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. Moreover, from the viewpoint of obtaining a stable emulsion, it is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0135] In this invention, there are no particular restrictions on the mixing order of the components of the oil-water mixture. For example, component (A) may be mixed after component (B1) is added, and components (B2) and (C) may be mixed as needed; alternatively, pre-prepared aqueous and oil phase components may be mixed.

[0136] It should be noted that when the components of the above oil-water mixture are solids, heating can also be performed during mixing.

[0137] In this invention, the oil-water mixture is preferably prepared by a method comprising steps 1 to 3 described below.

[0138] Step 1: The process of preparing an aqueous phase component containing a cationic surfactant.

[0139] Step 2: The process of preparing the oil phase by mixing component (A), component (B1), and components (B2) and (C) as needed.

[0140] Step 3: Adding the oil phase component obtained in Step 2 to the aqueous phase component obtained in Step 1 to obtain an oil-water mixture.

[0141] After emulsifying the above oil-water mixture, it is used for sol-gel reaction.

[0142] There are no particular limitations on the stirring apparatus used for emulsifying the above-mentioned oil-water mixture; homogenizers with shear force, high-pressure dispersers, ultrasonic dispersers, etc., can be used. In addition, homogenizers, "Disper" (trade name, manufactured by Primix Co., Ltd.), "CLEARMIX" (trade name, manufactured by M-Technique Co., Ltd.), "CAVITRON" (trade name, manufactured by Taihei Kiko Co., Ltd.), etc., can also be used.

[0143] From the viewpoint of manufacturing stability, the temperature at which the oil-water mixture emulsifies is preferably 5°C or higher, more preferably 8°C or higher, even more preferably 10°C or higher, and even more preferably 15°C or higher. Moreover, it is preferably 50°C or lower, more preferably 40°C or lower, even more preferably 35°C or lower, and even more preferably 30°C or lower.

[0144] Regarding the stirring speed and the emulsification time of the oil-water mixture, it is preferable to use the median droplet size D of the emulsion as the reference value. 50 The manner in which it becomes part of the scope described later shall be appropriately adjusted.

[0145] From the perspective of reducing the specific surface area of ​​microcapsules relative to the external environment and improving the long-term retention of functional oils, the median particle size D of the emulsion droplets obtained by emulsifying the above-mentioned oil-water mixture is considered important. 50 Preferably, the particle size is 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more. Furthermore, from the viewpoint of improving the physical strength of the microcapsules and the long-term retention of the functional oil, and from the viewpoint of improving the controllability of the microcapsule particle size, it is preferably 50 μm or less, more preferably 30 μm or less, even more preferably 10 μm or less, even more preferably 5 μm or less, and even more preferably 3 μm or less.

[0146] The median particle size D described in the examples can be determined. 50 .

[0147] <Soluble-gel reaction>

[0148] From the viewpoint of maintaining a balance between the hydrolysis and condensation reactions of the shell precursor, and from the viewpoint of suppressing the formation of highly hydrophilic sols and promoting encapsulation, the initial pH of the sol-gel reaction in step I is preferably 3.0 or higher, more preferably 3.3 or higher, and even more preferably 3.5 or higher. Furthermore, from the viewpoint of suppressing the simultaneous formation of the shell and the aggregation of emulsion droplets, and from the viewpoint of obtaining microcapsules with dense shells, it is preferably 4.5 or lower, more preferably 4.3 or lower, and even more preferably 4.1 or lower.

[0149] In order to adjust the initial pH of the above sol-gel reaction to the desired range, it is preferable to add any acidic or alkaline pH adjuster to the emulsion according to the strength of the acidity and alkalinity of the oil phase components containing components (A) and (B1).

[0150] If the pH of the emulsion is below the desired value, it is preferable to use an alkaline pH adjuster for adjustment.

[0151] When the pH of the emulsion is above the desired value, it is preferable to use an acidic pH adjuster for adjustment.

[0152] Examples of acidic pH adjusters include: inorganic acids such as sulfuric acid, sulfurous acid, hydrochloric acid, and nitric acid; aromatic sulfonic acid compounds such as p-toluenesulfonic acid and benzenesulfonic acid; aliphatic sulfonic acid compounds such as methanesulfonic acid; and organic acids such as citric acid; as well as liquids such as cation exchange resins added to water or ethanol.

[0153] Examples of alkaline pH adjusters include: hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide; bicarbonates of alkali metals such as sodium bicarbonate; ammonia; ammonium hydroxide; and organic amines such as diethanolamine, triethanolamine, and tris(hydroxymethyl)aminomethane. Preferably, one or more of sodium hydroxide and ammonium hydroxide are selected.

[0154] Regarding the pH adjuster mentioned above, one or more types can be used.

[0155] Regarding the reaction temperature of the sol-gel reaction in step I, any value can be selected as long as it is above the melting point and below the boiling point of water contained as the dispersion medium. However, in order to control the balance between the hydrolysis and condensation reactions in the sol-gel reaction and form a dense and firm shell, it is preferable to adjust it to 5°C or higher, more preferably to 10°C or higher, even more preferably to 15°C or higher, and preferably to 60°C or lower, more preferably to 50°C or lower, and even more preferably to 40°C or lower.

[0156] In this invention, the microcapsules obtained by step I are obtained in the form of an aqueous dispersion containing microcapsules dispersed in water.

[0157] In this invention, depending on the intended use of the microcapsules, they can be used directly as an aqueous dispersion. However, depending on the intended use of the microcapsules, they can also be used after being separated from the aqueous dispersion. Separation methods include filtration and centrifugation.

[0158] In this invention, from the viewpoint of improving the long-term retention of functional oils, it is preferable to further include the following step (hereinafter also referred to as "step II"): adding component (C) to the aqueous dispersion containing microcapsules obtained in step I above, and performing a sol-gel reaction to form microcapsules having a shell that further encapsulates the microcapsules.

[0159] Hereinafter, the shell formed by process I will also be referred to as the "first shell", and the shell formed by process II will also be referred to as the "second shell".

[0160] The temperature of the sol-gel reaction in step II can also be the same as that in step I.

[0161] From the viewpoint of improving the long-term retention of functional oils, the amount of component (C) in step II is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, relative to the amount of component (A). Furthermore, from the viewpoint of suppressing the residue of shell precursor inside the oil phase droplets and effectively carrying out the conversion to shell, it is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

[0162] The median particle size D of the microcapsules of the present invention 50 Depending on the type of shell, the size varies. For example, in the case of silica capsules, from the viewpoint of improving the long-term retention of functional oils and the dispersion stability of silica capsules, a size of 0.1 μm or more is preferred, more preferably 0.5 μm or more, and even more preferably 0.7 μm or more. Furthermore, from the viewpoint of improving the physical strength of silica capsules to enhance the long-term retention of functional oils and improving the controllability of microcapsule particle size, a size of 50 μm or less is preferred, more preferably 30 μm or less, even more preferably 10 μm or less, and even more preferably 5 μm or less.

[0163] Regarding the median particle size D of the aforementioned microcapsules 50 It can be determined by the method described in the examples.

[0164] The microcapsules of the present invention can be used for various purposes, such as in cosmetics, cleansers, softeners, anti-wrinkle sprays, hygienic products such as diapers, and fragrances.

[0165] The microcapsules of the present invention can be formulated into compositions of cleaning agents, fiber treatment agents, cosmetics, fragrances, deodorants, etc. Preferably, such compositions are cleaning agent compositions such as powder cleaning agent compositions and liquid cleaning agent compositions, and fiber treatment agent compositions such as softener compositions; more preferably, fiber treatment agent compositions; and even more preferably, softener compositions.

[0166] In addition to the above-described embodiments, the present invention also discloses the following microcapsules and a method for manufacturing microcapsules.

[0167] <1> A microcapsule, wherein,

[0168] It has: a shell comprising inorganic matter as its constituent parts; and a core containing one or more organic compounds inside the shell.

[0169] The organic compound contains the following components (A) and (B1).

[0170] Ingredient (A): Functional oil,

[0171] Ingredient (B1): Selected from one or more of the following: higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having alkyl groups having 6 or more carbon atoms, and amide compounds having alkyl groups having 8 or more carbon atoms (excluding ingredient (A)).

[0172] <2> According to the microcapsule described in <1> above, the molecular weight of component (B1) is preferably 500 or less, more preferably 450 or less, even more preferably 400 or less, even more preferably 350 or less, and preferably 150 or more.

[0173] <3> According to the microcapsules described in <1> or <2> above, the component (B1) is preferably selected from one or more of higher fatty acids having 6 or more carbon atoms and higher aliphatic alcohols having 6 or more carbon atoms, and more preferably higher fatty acids having 6 or more carbon atoms.

[0174] <4> According to the microcapsules described in <1> or <2> above, the component (B1) is preferably selected from one or more of alkyl glycerol ethers having an alkyl group having 8 or more carbon atoms and higher fatty acids having 6 or more carbon atoms, and more preferably alkyl glycerol ethers having an alkyl group having 8 or more carbon atoms.

[0175] <5> According to any one of <1> to <4> above, the microcapsule contains component (B1) in a proportion of 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less, and even more preferably 4% by mass or less.

[0176] <6> According to any one of <1> to <5> above, the microcapsule, wherein the organic compound further comprises the following component (B2).

[0177] Component (B2): Selected from one or more fatty acid esters with a total carbon number of 6 or more and higher alkanes with a carbon number of 6 or more (excluding component (A)).

[0178] <7> According to the microcapsule described in <6> above, the cLogP value of component (B2) is preferably 4 or more, more preferably 5 or more, even more preferably 6 or more, even more preferably 7 or more, and preferably 10 or less, more preferably 9 or less.

[0179] <8> According to the microcapsules described in <6> or <7> above, the component (B2) is preferably a fatty acid ester with a total carbon number of 6 or more.

[0180] <9> According to any one of <6> to <8> above, the microcapsule contains component (B2) in a proportion of 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, even more preferably 0.7% by mass or more, and preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less, even more preferably 4% by mass or less, and even more preferably 3% by mass or less.

[0181] <10> According to any one of <1> to <9> above, the microcapsule, wherein component (A) is preferably selected from one or more of fragrances, fragrance precursors, humectants, antioxidants, antibacterial agents, fertilizers, fibers, skin, and hair surface modifiers, cooling agents, dyes, pigments, silicones, and oil-soluble polymers; more preferably selected from one or more of fragrances, fragrance precursors, humectants, antioxidants, antibacterial agents, fertilizers, and surface modifiers; even more preferably selected from one or more of fragrances, fragrance precursors, humectants, and antioxidants; even more preferably selected from one or more of fragrances, fragrance precursors, and humectants; and even more preferably selected from one or more of fragrances and fragrance precursors.

[0182] <11> According to any one of <1> to <10> above, the cLogP value of component (A) is preferably 1 or more, more preferably 2 or more, even more preferably 3 or more, and preferably 30 or less, more preferably 20 or less, even more preferably 10 or less.

[0183] <12> According to any one of <1> to <11> above, the inorganic material is preferably an inorganic polymer formed by a sol-gel reaction using an alkoxide of one or more metals selected from silicon, aluminum and titanium as a shell precursor, and more preferably an alkoxysilane polymer.

[0184] <13> According to any one of <1> to <12> above, the median particle size D of the microcapsule is 50 Preferably, the micrometer is 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 0.7 μm or more, and preferably 50 μm or less, more preferably 30 μm or less, even more preferably 10 μm or less, and even more preferably 5 μm or less.

[0185] <14> A method for manufacturing microcapsules, wherein,

[0186] The microcapsule has: a shell containing inorganic matter as a constituent component, and a core containing one or more organic compounds inside the shell.

[0187] The method for manufacturing the microcapsules includes the following steps: emulsifying an oil-water mixture containing oil phase components and aqueous phase components and subjecting it to a sol-gel reaction to form microcapsules.

[0188] The oil phase composition contains the following components (A), (B1) and (C).

[0189] Ingredient (A): Functional oil,

[0190] Ingredient (B1): Selected from one or more of the following: higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having alkyl groups having 6 or more carbon atoms, and amide compounds having alkyl groups having 8 or more carbon atoms (excluding ingredient (A)).

[0191] Ingredient (C): Shell precursor.

[0192] <15> According to the method for manufacturing microcapsules described in <14> above, the oil phase component of the oil-water mixture further includes the following component (B2).

[0193] Component (B2): Selected from one or more fatty acid esters with a total carbon number of 6 or more and higher alkanes with a carbon number of 6 or more (excluding component (A)).

[0194] <16> According to the method for manufacturing microcapsules described in <15> above, the amount of component (B2) relative to the total amount of the oil-water mixture is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, even more preferably 0.7% by mass or less, even more preferably 0.5% by mass or less, and preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.15% by mass or more.

[0195] <17> The method for manufacturing microcapsules according to any one of <14> to <16> above, wherein component (C) is preferably an alkoxide selected from one or more metals selected from silicon, aluminum and titanium, and more preferably an alkoxysilane.

[0196] <18> According to any one of <14> to <17> above, the method for manufacturing microcapsules, wherein the amount of component (C) relative to the amount of component (A) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and preferably 100% by mass or less, more preferably 70% by mass or less, even more preferably 50% by mass or less, and even more preferably 30% by mass or less.

[0197] <19> The method for manufacturing microcapsules according to any one of <14> to <18> above, wherein the aqueous phase component of the oil-water mixture contains a cationic surfactant.

[0198] <20> According to the method for manufacturing microcapsules described in any one of <14> to <19> above, wherein the median particle size D of the emulsion droplets obtained by emulsifying the above-mentioned oil-water mixture is... 50 Preferably, the micrometer is 0.1 μm or more, more preferably 0.2 μm or more, even more preferably 0.3 μm or more, and preferably 50 μm or less, more preferably 30 μm or less, even more preferably 10 μm or less, even more preferably 5 μm or less, and even more preferably 3 μm or less.

[0199] <21> A microcapsule, wherein,

[0200] It has: a shell comprising an alkoxysilane polymer as a constituent component; and a core containing one or more organic compounds inside the shell.

[0201] The organic compound contains the following components (A) and (B1).

[0202] Ingredient (A): Functional oil,

[0203] Ingredient (B1): Selected from one or more of the following: higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having alkyl groups having 6 or more carbon atoms, and amide compounds having alkyl groups having 8 or more carbon atoms (excluding ingredient (A)).

[0204] The molecular weight of component (B1) is below 500.

[0205] The content of component (B1) relative to component (A) is more than 0.01% by mass and less than 10% by mass.

[0206] <22> According to the microcapsule described in <21> above, the cLogP value of component (A) is preferably 1 or more, more preferably 2 or more, even more preferably 3 or more, and preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less.

[0207] <23> A microcapsule, wherein,

[0208] It has: a shell comprising an alkoxysilane polymer as a constituent component; and a core containing one or more organic compounds inside the shell.

[0209] The organic compound contains the following components (A), (B1), and (B2).

[0210] Ingredient (A): Functional oil,

[0211] Ingredient (B1): Selected from one or more of the following: higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having alkyl groups having 6 or more carbon atoms, and amide compounds having alkyl groups having 8 or more carbon atoms (excluding ingredient (A)).

[0212] Component (B2): Selected from one or more fatty acid esters with a total carbon number of 6 or more and higher alkanes with a carbon number of 6 or more (excluding component (A)).

[0213] The content of component (B1) relative to component (A) is more than 0.01% by mass and less than 10% by mass.

[0214] The content of component (B2) relative to component (A) is more than 0.01% by mass and less than 10% by mass.

[0215] <24> According to the microcapsule described in <23> above, the molecular weight of component (B1) is preferably 500 or less, more preferably 450 or less, even more preferably 400 or less, even more preferably 350 or less, and preferably 150 or more.

[0216] <25> According to the microcapsules described in <23> or <24> above, the cLogP value of component (B2) is preferably 4 or more, more preferably 5 or more, even more preferably 6 or more, even more preferably 7 or more, and preferably 10 or less, more preferably 9 or less.

[0217] <26> The microcapsule described in any one of <23> to <25> above, wherein the cLogP value of component (A) is preferably 1 or more, more preferably 2 or more, even more preferably 3 or more, and preferably 30 or less, more preferably 20 or less, even more preferably 10 or less.

[0218] [Example]

[0219] The various measurements used in the examples and comparative examples were performed by the following methods.

[0220] [Median particle size D] 50 ]

[0221] Regarding the median droplet size D of the emulsion... 50 and the median particle size D of the microcapsules 50 The particle size distribution was measured using a laser diffraction / scattering particle size distribution measuring device, "LA-960" (trade name, manufactured by Horiba Manufacturing Co., Ltd.). During the measurement, a flow cell was used, water was used as the medium, and the refractive index was set to 1.45-0i. An aqueous dispersion containing emulsion or silica capsules was added to the flow cell, and the concentration was measured at approximately 90% transmittance. The median particle size D was determined on a volume basis. 50 .

[0222] <Model Spice>

[0223] As component (A) encapsulated in the microcapsules, model fragrance A1 with the composition shown in Table 1 (volume average cLogP value: 3.7, specific gravity: 0.97, oil-water interfacial tension: 17.0 mN / m) and model fragrance A2 with the composition shown in Table 2 (volume average cLogP value: 3.7, specific gravity: 0.97, oil-water interfacial tension: 16.3 mN / m) were used. It should be noted that the volume average cLogP value of the above model fragrances is calculated by multiplying the cLogP value of each fragrance component contained in the model fragrance by its volume ratio, and then summing the results.

[0224] [Table 1]

[0225] Table 1: Model Fragrance A1

[0226]

[0227] *1: AMBERCORE (trade name, manufactured by Kao Corporation)

[0228] [Table 2]

[0229] Table 2: Model Fragrance A2

[0230]

[0231] *1: AMBERCORE (trade name, manufactured by Kao Corporation)

[0232] Details of the compounds used in the examples or comparative examples are as follows.

[0233] Cetyl alcohol: Manufactured by Kao Corporation, cLogP value: 6.7, melting point: 49~52℃.

[0234] Isostearic acid: manufactured by Higher Alcohols Industry Co., Ltd., cLogP value: 7.9, melting point: cloud point below 10°C.

[0235] Squalene (α-monostearylglycerol ether): manufactured by Tokyo Chemical Industry Co., Ltd., cLogP value: 7.2, melting point: 71℃.

[0236] Isopropyl palmitate: manufactured by Kao Corporation, cLogP value: 8.2, melting point: 8-15℃.

[0237] Example 1

[0238] (Process I)

[0239] Aqueous phase was prepared by diluting 0.60 g of QUARTAMIN 60W (trade name, manufactured by Kao Corporation; cetyltrimethylammonium chloride (hereinafter referred to as "CTAC"), active ingredient 30% by mass) with 149.40 g of deionized water. An oil phase was prepared by premixing 38.4 g of model fragrance A1 as component (A), 10 g of tetraethoxysilane (hereinafter referred to as "TEOS") as component (C), 1.2 g of cetyl alcohol as component (B1), and 0.4 g of isopropyl palmitate as component (B2) into this aqueous phase, resulting in an oil-water mixture.

[0240] The resulting oil-water mixture was emulsified for 8 minutes at room temperature (approximately 25°C) using a homogenizer (HsiangTai Co., Ltd., model: HM-310) set to 8,500 rpm to obtain an emulsion. The median droplet size D of the emulsion at this point was... 50It is 1.1 μm.

[0241] Next, the pH of the emulsion was adjusted to 3.7 using a 1% sulfuric acid aqueous solution, and then transferred to a separate flask equipped with a stirring blade. The liquid temperature was maintained at 30°C, and the mixture was stirred at 200 rpm for 24 hours to obtain an aqueous dispersion (1) containing silica capsules (the silica capsules having a core composed of components (A), (B1), and (B2) and a shell composed of silica). The median particle size D of the silica capsules in the aqueous dispersion (1) is... 50 It is 1.7μm.

[0242] Example 2

[0243] (Process I)

[0244] Aqueous phase was prepared by diluting 0.60g of QUARTAMIN 60W (trade name, manufactured by Kao Corporation; cetyltrimethylammonium chloride, 30% by mass of active ingredient) with 149.40g of deionized water. An oil phase was then added to this aqueous phase, premixed with 38.8g of model fragrance A2 as component (A), 10g of TEOS as component (C), and 1.2g of cetyl alcohol as component (B1), to obtain an oil-water mixture.

[0245] The resulting oil-water mixture was emulsified for 8 minutes at room temperature (approximately 25°C) using the aforementioned homogenizer set to 8,500 rpm to obtain an emulsion. The median droplet size D of the emulsion at this point is... 50 It is 1.0 μm.

[0246] Next, the pH of the emulsion was adjusted to 3.7 using a 1% sulfuric acid aqueous solution, and then transferred to a separate flask equipped with a stirring blade. The liquid temperature was maintained at 30°C, and the mixture was stirred at 200 rpm for 24 hours to obtain an aqueous dispersion (2) containing silica capsules (the silica capsules having a core composed of components (A) and (B1) and a shell composed of silica). The median particle size D of the silica capsules in the aqueous dispersion (2) is... 50 It is 2.2 μm.

[0247] Comparative Example 1

[0248] (Process I')

[0249] Aqueous phase was prepared by diluting 0.60g of QUARTAMIN 60W (trade name: Kao Corporation; cetyltrimethylammonium chloride, active ingredient 30% by mass) with 149.40g of deionized water. An oil phase was then added to this aqueous phase, consisting of 40g of model fragrance A1 as component (A) and 10g of TEOS as component (C), to obtain an oil-water mixture.

[0250] The resulting oil-water mixture was emulsified for 8 minutes at room temperature (approximately 25°C) using the aforementioned homogenizer set to 8,500 rpm to obtain an emulsion. The median droplet size D of the emulsion at this point is... 50 It is 2.0 μm.

[0251] Next, the pH of the emulsion was adjusted to 3.7 using a 1% (w / w) sulfuric acid aqueous solution, and then transferred to a separate flask equipped with a stirring blade. The liquid temperature was maintained at 30°C, and the mixture was stirred at 200 rpm for 24 hours to obtain an aqueous dispersion (C1) containing silica capsules with a core composed of component (A) and a shell composed of silica. The median particle size D of the silica capsules in this aqueous dispersion (C1) is... 50 It is 2.6 μm.

[0252] Example 3

[0253] (Process I)

[0254] The same procedure as in Example 1 was performed to obtain an aqueous dispersion (1) containing silica capsules.

[0255] (Process II)

[0256] Next, 150g of the aqueous dispersion (1) was added with 4.5g of TEOS using an Atlas Syringe Pump (trade name, Syrris) over 7 hours. The liquid temperature was maintained at 30°C while stirring for 24 hours, and then cooled to room temperature. This formed a second shell encapsulating the aforementioned silica capsules, resulting in an aqueous dispersion (3) containing silica capsules (in which components (A), (B1), and (B2) are encapsulated by amorphous silica). The median particle size D of the silica capsules in the aqueous dispersion (3) is... 50 It is 1.9μm.

[0257] Example 4

[0258] (Process I)

[0259] The same procedure as in Example 2 was performed to obtain an aqueous dispersion (2) containing silica capsules.

[0260] (Process II)

[0261] Next, 150g of the aqueous dispersion (2) was supplemented with 4.5g of TEOS using the aforementioned drop pump over 7 hours. The liquid temperature was maintained at 30°C while stirring for 24 hours, and then cooled to room temperature. This formed a second shell encapsulating the aforementioned silica capsules, resulting in an aqueous dispersion (4) containing silica capsules (in which components (A) and (B1) are encapsulated by amorphous silica). The median particle size D of the silica capsules in the aqueous dispersion (4) is... 50 It is 2.2 μm.

[0262] Example 5

[0263] (Process I)

[0264] Aqueous phase was prepared by diluting 0.60g of QUARTAMIN 60W (trade name: Kao Corporation; cetyltrimethylammonium chloride, active ingredient 30% by mass) with 149.40g of deionized water. An oil phase was then prepared by premixing 38.8g of model fragrance A2 as component (A), 10g of TEOS as component (C), and 1.2g of isostearic acid as component (B1) into this aqueous phase, resulting in an oil-water mixture.

[0265] The oil-water mixture was emulsified for 15 minutes at room temperature (approximately 25°C) using a homogenizer set to 8,000 rpm to obtain an emulsion. The median droplet size D of the emulsion at this point was... 50 It is 0.7μm.

[0266] Next, the pH of the above emulsion was adjusted to 3.7 using a 1% sulfuric acid aqueous solution, and then transferred to a separate flask equipped with a stirring blade. The liquid temperature was maintained at 30°C, and the mixture was stirred at 200 rpm for 24 hours to obtain an aqueous dispersion (5') containing silica capsules (which have a core composed of components (A) and (B1) and a first shell composed of silica).

[0267] (Process II)

[0268] Next, 5.5 g of TEOS was added to the aqueous dispersion (5') using the aforementioned drop pump over 7 hours, followed by further stirring for 17 hours and cooling to room temperature. This formed a second shell encapsulating the aforementioned silica capsules, resulting in an aqueous dispersion (5) containing silica capsules (in which components (A) and (B1) are encapsulated by amorphous silica). The median particle size D of the silica capsules in this aqueous dispersion (5) is... 50 It is 0.9μm.

[0269] Example 6

[0270] (Process I)

[0271] Aqueous phase was prepared by diluting 0.61g of QUARTAMIN 60W (trade name, Kao Corporation; cetyltrimethylammonium chloride, active ingredient 30% by mass) with 149.11g of deionized water. An oil phase was then prepared by premixing 38.9g of model fragrance A2 as component (A), 10g of TEOS as component (C), and 1.2g of squalene as component (B1) into this aqueous phase, resulting in an oil-water mixture.

[0272] The resulting oil-water mixture was emulsified for 8 minutes at room temperature (approximately 25°C) using the aforementioned homogenizer set to 8,500 rpm to obtain an emulsion. The median droplet size D of the emulsion at this point is... 50 It is 0.7μm.

[0273] Next, the pH of the above emulsion was adjusted to 3.7 using a 1% sulfuric acid aqueous solution, and then transferred to a separate flask equipped with a stirring blade. The liquid temperature was maintained at 30°C, and the mixture was stirred at 200 rpm for 24 hours to obtain an aqueous dispersion (6') containing silica capsules (which have a core composed of components (A) and (B1) and a first shell composed of silica).

[0274] (Process II)

[0275] Next, 25.36 g of the aqueous dispersion (6') was added with 0.71 g of TEOS over 10 seconds using the aforementioned drop pump. The liquid temperature was maintained at 30°C while stirring for 20 hours, and then cooled to room temperature. This formed a second shell encapsulating the aforementioned silica capsules, resulting in an aqueous dispersion (6) containing silica capsules (in which components (A) and (B1) are encapsulated by amorphous silica). The median particle size D of the silica capsules in the aqueous dispersion (6) is... 50 It is 1.5μm.

[0276] Comparative Example 2

[0277] (Process I')

[0278] Aqueous phase was prepared by diluting 0.60g of QUARTAMIN 60W (trade name: Kao Corporation; cetyltrimethylammonium chloride, active ingredient 30% by mass) with 149.41g of deionized water. An oil phase was then prepared by premixing 38.80g of model fragrance A1 (as component A), 10g of TEOS (as component C), and 1.2g of isopropyl palmitate (as component B2) into this aqueous phase, resulting in an oil-water mixture.

[0279] The resulting oil-water mixture was emulsified for 8 minutes at room temperature (approximately 25°C) using the aforementioned homogenizer set to 8,500 rpm to obtain an emulsion. The median droplet size D of the emulsion at this point is... 50 It is 1.9μm.

[0280] Next, the pH of the emulsion was adjusted to 3.7 using a 1% sulfuric acid aqueous solution, and then transferred to a separate flask equipped with a stirring blade. The liquid temperature was maintained at 30°C, and the mixture was stirred at 200 rpm for 24 hours to obtain an aqueous dispersion (C2') containing silica capsules (which have a core composed of components (A) and (B2) and a first shell composed of silica).

[0281] (Process II)

[0282] Next, 190.00 g of the aqueous dispersion (C2') was added with an additional 5.7 g of TEOS over 7 hours using the aforementioned drop pump. The liquid temperature was maintained at 30°C while stirring for another 17 hours, followed by cooling to room temperature. This formed a second shell encapsulating the aforementioned silica capsules, resulting in an aqueous dispersion (C2) containing silica capsules (in which components (A) and (B2) are encapsulated by amorphous silica). The median particle size D of the silica capsules in the aqueous dispersion (C2) is... 50 It is 1.4μm.

[0283] Examples 7-9 and Comparative Example 3

[0284] In Example 3, the amounts of cetyl alcohol as component (B1) or isopropyl palmitate as component (B2) were changed to those shown in Table 3, and the rotation speed of the homogenizer and the emulsification time used in the emulsification of the oil-water mixture were set to the conditions shown in Table 3. Otherwise, the process was carried out in the same manner as in Example 3, and aqueous dispersions (7) to (9) and (C3) containing silica capsules were obtained. The median particle size D of the emulsion droplets is shown in Table 3. 50 and the median particle size D of silica capsules 50 .

[0285] [Table 3]

[0286] Table 3

[0287]

[0288] *1: Amount added relative to ingredient (A) (by mass%)

[0289] According to the comparison between Example 7 and Comparative Example 3 in Table 3, the median particle size D of the obtained silica capsules is [affected by the amount of component (B1) added]. 50 It gets smaller.

[0290] According to Examples 3, 8, and 9 in Table 3, as the amount of component (B2) added increases, the median particle size D of the obtained silica capsules increases. 50 It gets smaller.

[0291] Therefore, according to the present invention, by adjusting the amount of component (B1) or component (B2), microcapsules with smaller particle sizes can be obtained, and the particle size of the microcapsules can be controlled. Therefore, it is useful in the formulation of microcapsules corresponding to the design and application. In addition, it is believed that the physical strength of the microcapsules with smaller particle sizes is also improved, and therefore, it is believed that disintegration during the flow stage of the microcapsules is suppressed, and the storage stability is also improved.

[0292] [Evaluation of Microcapsules]

[0293] 0.79 g of each aqueous dispersion containing silica capsules obtained in Examples 1-6 and Comparative Examples 1-2, 1.61 g of deionized water, and 27.60 g of unfragranted fabric softener "Flairfragrance" (trade name) manufactured by Kao Corporation were measured into glass vials and dispersed thoroughly by hand to prepare an evaluation fabric softener. The long-term retention of fragrance components within the microcapsules in the fabric softener was evaluated using the method described below. The results are shown in Tables 4 and 5.

[0294] First, using a dropper, 0.3 g of the aforementioned evaluation softener, which had been stored at 40°C for 6 or 7 days, was drawn up and diluted with 120 g of a 0.2% cyclohexanol aqueous solution. The solution was then shaken to disperse it thoroughly. 50 g of the resulting diluted solution was then rapidly passed through a membrane filter (Millipore, product name "Omnipore", model "JAWP04700"), thereby recovering the silica capsules on the membrane filter. (At this point, if necessary, the mouth of the Erlenmeyer flask containing the diluted solution was immersed in a water bath set to 50°C for 10–15 minutes before passing through the membrane filter.) Furthermore, the silica capsules were rinsed with 10 mL of deionized water over a membrane filter, followed by 10 mL of hexane. Then, the capsules were immersed in 2 mL of methanol containing dodecane at a concentration of 20 μg / mL, serving as an internal standard. The capsules were then irradiated with ultrasound for 60 minutes using an ultrasonic irradiation device (Branson, model "5510") at an output of 180 W and an oscillation frequency of 42 kHz, causing the fragrances within the silica capsules to dissolve. Next, the solution was passed through a membrane filter (Toyo Filter Paper Co., Ltd., product name "DISMIC", model "13JP020AN"), and the fragrance components in the resulting solution were determined using gas chromatography. The GC peak area ratio α of each fragrance component within the preserved silica capsules relative to the internal standard was calculated.

[0295] On the other hand, 80 mg of each aqueous dispersion containing silica capsules obtained in Examples 1-6 and Comparative Examples 1-2 was immersed in 40 mL of methanol containing dodecane at a concentration of 20 μg / mL as an internal standard. The mixture was then irradiated with ultrasound for 60 minutes using an ultrasonic irradiation device (Branson, model "5510") at an output of 180 W and an oscillation frequency of 42 kHz to dissolve the fragrance from the silica capsules. Next, the solution was passed through a membrane filter (Toyo Filter Paper Co., Ltd., product name "DISMIC", model "13JP020AN"), and the fragrance components contained in the resulting solution were determined by gas chromatography. The GC peak area ratio β of each fragrance component in the aqueous dispersion containing silica capsules before storage relative to the internal standard was calculated.

[0296] Next, the fragrance retention rate was calculated using the following formula, based on the proportions of each fragrance component encapsulated in the silica capsule after long-term storage. A higher fragrance retention rate indicates better long-term preservation.

[0297] Flavor retention rate (%) = {(GC peak area ratio α of each flavor component in the preserved silica capsule relative to the internal standard) × (volume of methanol used for extraction) / (amount of aqueous dispersion containing silica capsules for evaluation)} / {(GC peak area ratio β of each flavor component in the aqueous dispersion containing silica capsules before preservation relative to the internal standard) × (volume of methanol used for extraction) / (amount of aqueous dispersion containing silica capsules for evaluation)} × 100

[0298] [Table 4]

[0299] Table 4

[0300]

[0301] *1: Amount added relative to ingredient (A) (by mass%).

[0302] [Table 5]

[0303] Table 5

[0304]

[0305] *1: Amount added relative to ingredient (A) (by mass%).

[0306] As can be seen from Tables 4 and 5, the silica capsules of the Examples exhibit superior long-term retention of fragrance components compared to the Comparative Examples.

[0307] It is believed that, in the embodiments, because the oil phase component of the oil-water mixture at least includes component (B1), although the rotation speed of the homogenizer and the emulsification time during emulsification are the same as in the comparative example, a smaller median particle size D is formed compared to the comparative example. 50 The emulsion droplets, which are stable and micronized, undergo a rapid sol-gel reaction, thus improving the long-term retention of fragrance components.

[0308] [Industry availability]

[0309] According to the present invention, a microcapsule and a method for manufacturing the microcapsule are provided. The microcapsules of the present invention can retain the encapsulated functional oils such as fragrances for a long period of time, and further exhibit excellent particle size control. In addition, according to the present invention, the excellent particle size control improves the physical strength of the small-particle-size silica capsules, and the stability of the microcapsules during the flow stage is also excellent. Therefore, it is also useful in the formulation of microcapsules designed for specific applications, and the microcapsules can be well applied to various products formulated with functional oils such as fragrances.

Claims

1. A microcapsule, wherein, The microcapsule has a shell and a core, wherein the shell contains inorganic matter as a constituent component, and the core contains one or more organic compounds inside the shell. The organic compound comprises component (A), component (B1), and component (B2) as described below, wherein component (B1) is present in an amount of 0.01% to 7% by mass relative to component (A), and component (B2) is present in an amount of 1% to 10% by mass relative to component (A). Ingredient (A): Functional oil, Ingredient (B1): Selected from one or more of the following: higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having an alkyl group having 6 or more carbon atoms, and amide compounds having an alkyl group having 8 or more carbon atoms, excluding ingredient (A). Component (B2): Fatty acid esters with a total number of 6 or more carbon atoms, excluding component (A).

2. The microcapsule according to claim 1, wherein, The molecular weight of component (B1) is below 500.

3. The microcapsule according to claim 1 or 2, wherein, The content of component (B1) relative to component (A) is more than 0.1% by mass and less than 5% by mass.

4. The microcapsule according to any one of claims 1 to 3, wherein, The content of component (B2) relative to component (A) is more than 1% by mass and less than 3% by mass.

5. The microcapsule according to any one of claims 1 to 4, wherein, Component (A) is selected from one or more of the following: fragrances, fragrance precursors, humectants, antioxidants, antibacterial agents, fertilizers, and surface modifiers.

6. The microcapsule according to any one of claims 1 to 5, wherein, The inorganic material is an inorganic polymer formed by a sol-gel reaction using an alkoxide of one or more metals selected from silicon, aluminum, and titanium as a precursor.

7. A method for manufacturing microcapsules, wherein, The microcapsule has a shell and a core. The shell contains inorganic matter as a constituent component, and the core contains one or more organic compounds inside the shell. The method for manufacturing the microcapsules includes the following steps: emulsifying an oil-water mixture containing oil phase components and aqueous phase components and subjecting it to a sol-gel reaction to form microcapsules. The oil phase composition contains the following components (A), (B1) and (C). Ingredient (A): Functional oil, Ingredient (B1): Selected from one or more of the following: higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having an alkyl group having 6 or more carbon atoms, and amide compounds having an alkyl group having 8 or more carbon atoms, excluding ingredient (A). Ingredient (C): Shell precursor.

8. The method for manufacturing microcapsules according to claim 7, wherein, The oil phase of the oil-water mixture also includes the following component (B2). Component (B2): Selected from one or more fatty acid esters with a total carbon number of 6 or more and higher alkanes with a carbon number of 6 or more, except for component (A).

9. The method for manufacturing microcapsules according to claim 8, wherein, Component (B2) is a fatty acid monoester, except for component (A).

10. A microcapsule, wherein, The microcapsule has a shell and a core, wherein the shell contains an alkoxysilane polymer as a constituent component, and the core contains one or more organic compounds inside the shell. The organic compound comprises component (A), component (B1), and component (B2) as described below, wherein component (B1) is present in an amount of 0.01% to 7% by mass relative to component (A), and component (B2) is present in an amount of 1% to 3% by mass relative to component (A). Ingredient (A): Selected from one or more fragrances and fragrance precursors. Ingredient (B1): Selected from one or more of the following: higher aliphatic alcohols having 6 or more carbon atoms, higher fatty acids having 6 or more carbon atoms, monoalkyl glycerol ethers having an alkyl group having 6 or more carbon atoms, and amide compounds having an alkyl group having 8 or more carbon atoms, excluding ingredient (A). Component (B2): Fatty acid monoester, except for component (A).

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