Functional particles and methods for producing the same

Abstract

The present invention aims to improve the storage stability of functional particles. [Solution] A functional particle having a core-shell structure, comprising a core portion made of a functional material and a resin shell portion covering the core portion, wherein the core portion is a nanoparticle.

Description

Technical Field

[0001] The present invention relates to functional particles and a method for producing the same.

Background Art

[0002] Conventionally, various techniques have been provided for imparting various functions possessed by functional substances, such as photocatalytic substances, ultraviolet shielding materials, functional color materials such as leuco dyes, and latent heat storage materials, to an object.

[0003] However, these functional substances are rarely imparted in the form of the functional substances as they are, and various forms have been devised to add weather resistance, durability, storage stability, etc. to the functional substances.

[0004] For example, in Patent Document 1, in order to solve the problem of poor adhesion of an acrylic resin to a polyolefin, a method of dissolving a tackifier in an ethylenically unsaturated monomer and performing emulsion polymerization is proposed as a method of modifying the aqueous acrylic resin with a tackifier during production and making it present in the acrylic resin. Further, in Patent Document 2, core-shell type composite particles suitable for use in producing pigments, paints, cosmetics, ultraviolet shielding materials, optical materials, and electronic materials are proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, Patent Document 1 discloses a method of emulsion polymerization by dissolving a tackifying resin in an ethylenically unsaturated monomer. In this method, a large amount of coarse particles larger than 2 μm containing a high concentration of tackifying resin may be generated during polymerization, and these particles may settle during storage. Furthermore, Patent Document 2 only mixes functional substances into the core resin particles constituting the core layer of the core-shell type composite particle or the resin monomer liquid constituting the shell layer, which has problems in terms of the ability to sustainably retain the functional substances within the core-shell type composite particle.

[0007] Therefore, the present invention aims to improve the storage stability of functional particles. [Means for solving the problem]

[0008] To achieve the objectives of the present invention, the functional particles of the present invention have the following configuration: namely, functional particles having a core-shell structure, comprising a core portion made of a functional material and a resin shell portion covering the core portion, wherein the core portion is a nanoparticle. [Effects of the Invention]

[0009] According to the present invention, the storage stability of functional particles can be improved. [Brief explanation of the drawing]

[0010] [Figure 1] A figure showing an example of a SEM image of seed particles according to one embodiment. [Figure 2] A figure showing an example of a SEM image of functional particles according to one embodiment. [Modes for carrying out the invention]

[0011] The embodiments will be described in detail below. Note that the following embodiments do not limit the invention as defined in the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the features described in the embodiments may be combined in any way.

[0012] In this specification, the notation "A~B" representing a numerical range is synonymous with "greater than or equal to A" and "less than or equal to B," and includes both A and B.

[0013] <Functional particles> A functional particle with a core-shell structure according to one embodiment comprises a core made of a functional substance and a resin shell covering the core. Because the functional particle has a core-shell structure, a high concentration of the functional substance can be stably enclosed in the core, thereby exhibiting a higher level of functionality (hereinafter sometimes simply referred to as "function") of the functional substance than in conventional methods. Conventionally, the monomers that could be used in the manufacture of functional particles were limited. Conventional usable monomers were, for example, aromatic group-containing unsaturated monomers that could dissolve the functional substance. On the other hand, in the present invention, because the functional particle has a core-shell structure, there are no restrictions on the types of monomers that can be used. According to the present invention, monomers that do not easily dissolve the functional substance can also be used in the manufacture of functional particles.

[0014] The functional particles in one embodiment are nanoparticles. The functional particles may be any particles having a size on the order of nanometers (nm). The average particle diameter of the functional particles in one embodiment is 60 to 1000 nm, preferably 60 to 500 nm, and more preferably 150 to 350 nm. The average particle diameter of the functional particles is the particle diameter that represents 50% of the cumulative particle size distribution measured by dynamic light scattering (D50; median diameter).

[0015] <Core section> The core portion consists substantially of a functional material, but may also contain substances that are unavoidable in the production of functional particles. In one embodiment, the core portion is a nanoparticle. Here, the core portion may be any particle having a size on the order of nanometers (nm).

[0016] The average particle diameter of the core part according to one embodiment is 50 to 500 nm, preferably 50 to 300 nm, more preferably 100 to 300 nm. The average particle diameter of the core part is the particle diameter (D50; median diameter) at which the cumulative percentage is 50% in the volume-based particle size distribution measured by the dynamic light scattering method.

[0017] In one embodiment, among 100% by mass of the functional particles, 5 to 95% by mass, preferably 5 to 85% by mass, more preferably 30 to 85% by mass of the functional substance is contained.

[0018] (Functional substance) The functional substance is preferably a water-insoluble compound. Examples of the functional substance include functional dyes such as leuco dyes and fluorescent dyes, latent heat storage materials composed of hydrates, paraffins, and organic compounds, waxes composed of fatty acid esters and aliphatic hydrocarbons, etc. Also, polylactic acid, which is a biodegradable material from the perspective of carbon neutrality, and rosin-based tackifiers can also be said to be functional substances.

[0019] In one embodiment, the functional substance is any one of a tackifier, polylactic acid, a latent heat storage material, and a functional dye. A functional dye refers to a dye that undergoes light absorption, light emission, chemical change, or physical change due to external light, heat, electricity, pressure, electric field, etc. Functional dyes include, for example, fluorescent dyes.

[0020] Here, as one functional substance, the fluorescent dye will be described in detail. A fluorescent dye is a dye that emits fluorescence. When a fluorescent dye absorbs light, the electrons in the dye are excited, and when they return to the ground state, the extra energy is emitted as electromagnetic waves. This electromagnetic wave is fluorescence, and the wavelength of the fluorescence is always longer than the wavelength of the absorbed light (excitation light). The difference between the wavelength of the excitation light and the wavelength of the fluorescence is called the Stokes shift, and the larger this value is, the easier it is to distinguish the fluorescence from the excitation light, and the easier it is to detect the dye.

[0021] Examples of the fluorescent dye include compounds and derivatives having fluorescence characteristics such as merocyanine, perylene, acridine, anthracene, perylene, luciferin, pyrene, stilbene, rhodamine, coumarin, 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM), pyromethene, fluorescein, umbelliferone, tetraphenyl ethylene, etc., and one or more selected from the above group can be used. The fluorescent dye is preferably anthracene.

[0022] In addition, one type of fluorescent dye is the aggregation-induced emission (AIE) dye. The AIE dye is a fluorescent dye that does not emit light in a dilute solution state but emits strong light in a solid / aggregated state, showing behavior opposite to that of general fluorescent dyes. That is, the AIE dye is a dye that enables high concentration and high brightness, which were difficult with ordinary fluorescent dyes due to concentration quenching, etc.

[0023] Examples of the AIE dye include silole ring-containing compounds and derivatives such as 1,1-dimethyl-2,3,4,5-tetraphenylsilole, 1,1,2,3,4,5-hexaphenylsilole, 1,1-dimethyl-2,5-dianisyl-3,4-diphenylsilole, 1,1-diallyl-2,3,4,5-tetraphenylsilole, etc., hydrocarbon aromatic compounds and derivatives such as tetraphenyl ethylene, heteroaromatic compounds and derivatives, rhodamine-based compounds and derivatives, etc., and one or more selected from the above group can be used. The AIE dye is preferably tetraphenyl ethylene.

[0024] Furthermore, we will describe polylactic acid in detail as another functional substance. Polylactic acid is a polymer obtained by polymerizing lactic acid, and it is a polymer in which lactic acid is polymerized by ester bonds. Lactic acid is obtained by fermenting sugars such as glucose and sucrose with lactic acid bacteria. Sugars, which are the raw materials for lactic acid, can be obtained by extraction from sugarcane, etc., or by treating starch obtained from corn, potatoes, sweet potatoes, rice, and wheat with enzymes. Thus, polylactic acid is a plant-derived biomass material synthesized using plants, which are biomass, as the starting material. In addition, polylactic acid has the property of being hydrolyzed into low molecular weight by moisture in the environment and ultimately broken down into carbon dioxide and water by microorganisms, etc. (biodegradability). At this time, carbon dioxide is released into the atmosphere, but since plants absorb carbon dioxide from the atmosphere to synthesize starch, polylactic acid is said to be carbon neutral because, overall, it does not increase the amount of carbon dioxide, which is considered to be the cause of global warming.

[0025] Because lactic acid molecules have one chiral carbon, two optical isomers exist: D-lactic acid and L-lactic acid. Furthermore, racemic DL-lactic acid, a mixture of these two, exhibits properties different from those of the optically active form. Lactides and polylactic acids synthesized from these lactic acids also have optical isomers, and polylactic acids have various structural isomers with different properties depending on the composition of the optically isomerized lactic acid units. For example, polymers consisting solely of D-lactic acid (by polymerizing only D-lactic acid) and polymers consisting solely of L-lactic acid (by polymerizing only L-lactic acid) exhibit optical activity and are called poly-D-lactic acid (PDLA) and poly-L-lactic acid (PLLA), respectively. On the other hand, poly-DL-lactic acid (PDLLA), which consists of racemic DL-lactic acid, is optically inactive. From a polymeric structural standpoint, PDLA and PLLA adopt an isotact structure, forming a helical structure and exhibiting crystalline properties, while PDLLA has an atact structure, making it amorphous and glassy at room temperature. Furthermore, for example, a 1:1 mixture of PLLA and PDLA forms a different crystal, known as stereocomplex polylactic acid (SC-PLA), in which the helical structures interlock well, resulting in a highly heat-resistant resin.

[0026] Furthermore, we will describe tackifiers in detail as another functional substance. Generally, tackifiers are called tackifying resins. Tackifying resins are sometimes used to improve the biomass content of re-peelable adhesive compositions, and from the viewpoint of improving biomass content, it is preferable to use rosin-based resins and terpene-based resins.

[0027] Examples of rosin-based resins include natural rosin, rosin esters, hydrogenated rosin, hydrogenated rosin esters, polymerized rosin, polymerized rosin esters, disproportionated rosin, and disproportionated rosin esters.

[0028] Examples of terpene resins include α-pinene resin, β-pinene resin, terpene resin, hydrogenated terpene resin, aromatically modified terpene resin, and terpene phenol resin. Among these tackifying resins, natural rosin and ester resins derived from rosin (rosin esters, water-added rosin esters) are more preferred.

[0029] Furthermore, we will describe in detail another functional material: latent heat storage materials. Examples of latent heat storage materials include aliphatic hydrocarbons, fatty acids, fatty acid esters, fatty acid ethers, and aliphatic alcohols. In particular, from the viewpoint of ease of temperature setting according to the intended use and high stability (long lifespan), it is preferable that the latent heat storage material contains at least one selected from the group consisting of aliphatic hydrocarbons and fatty acid esters. The latent heat storage material is preferably butyl stearate and methyl stearate 95.

[0030] Examples of aliphatic hydrocarbons include linear aliphatic hydrocarbons such as n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-docosane, and other n-paraffins; petroleum-derived hydrocarbon waxes such as paraffin wax and microcrystalline wax; and synthetic hydrocarbon waxes such as polyethylene wax and Fischer-Tropsch wax. The number of carbon atoms in the above linear aliphatic hydrocarbons (n-paraffins) is preferably 8 to 40, more preferably 12 to 40, and even more preferably 14 to 40. Furthermore, the above waxes (hydrocarbon waxes) can also be used as supercooling inhibitors. It is preferable to use the supercooling inhibitor (hydrocarbon wax) in combination with other latent heat storage materials as a latent heat storage material, and it is more preferable to use the hydrocarbon wax and fatty acid esters in combination as a latent heat storage material.

[0031] The paraffin wax described above is a solid wax at room temperature (20°C ± 15°C) produced mainly by separation and purification from the oil portion of vacuum distillation of petroleum, and its main component is n-paraffin. The melting point of paraffin wax is preferably 40 to 70°C. The microcritalin wax described above is a solid wax at room temperature produced mainly by separation and purification from the oil residue portion of vacuum distillation of petroleum, and its main component is branched aliphatic hydrocarbons (isoparaffins) and / or alicyclic hydrocarbons (cycloparaffins). The melting point of microcritalin wax is preferably 60 to 90°C. The melting point of the synthetic hydrocarbon wax described above is preferably 40 to 130°C.

[0032] As fatty acids, for example, fatty acids with 8 to 30 carbon atoms can be used. Fatty acids can be broadly classified into straight-chain saturated fatty acids, straight-chain unsaturated fatty acids, branched saturated fatty acids, and branched unsaturated fatty acids, and among these, straight-chain saturated fatty acids are preferred. Examples of straight-chain saturated fatty acids include octanoic acid, nonanoic acid, decanoic acid (capric acid), dodecanoic acid (lauric acid), tetradecanoic acid (myristic acid), hexadecanoic acid (palmitic acid), octadecanoic acid (stearic acid), eicosanoic acid, docosanic acid, tetracosanoic acid, and hexacosanoic acid. Among these, straight-chain saturated fatty acids with 10 to 18 carbon atoms are more preferred due to their availability. Furthermore, straight-chain saturated fatty acids with a melting point in the range of 15 to 70°C are more preferred.

[0033] As fatty acid esters, for example, fatty acid esters having 8 to 30 carbon atoms can be used, and fatty acid esters with a melting point in the range of 10 to 30°C are preferably used. Suitable fatty acid esters include, for example, vinyl stearate, dimethyl sebacate, butyl stearate, isopropyl stearate, isopropyl palmitate, and propyl palmitate. Among these, methyl, ethyl, propyl, or butyl esters of straight-chain saturated fatty acids having 10 to 18 carbon atoms are more preferred due to their availability.

[0034] As the fatty acid ether, for example, a fatty acid ether having 14 to 60 carbon atoms can be used, and a fatty acid ether with a melting point in the range of -10 to 70°C is preferably used. Suitable fatty acid ethers include, for example, heptyl ether, octyl ether, tetradecyl ether, and hexadecyl ether.

[0035] As the aliphatic alcohol, for example, an aliphatic alcohol having 8 to 60 carbon atoms can be used, and an aliphatic alcohol with a melting point in the range of 15 to 80°C is preferably used. Suitable aliphatic alcohols include, for example, 2-dodecanol, 1-tetradecanol, 7-tetradecanol, 1-octadecanol, 1-eicosanol, and 1,10-decanediol.

[0036] <Shell section> The shell portion is a resin covering the core portion. In one embodiment, the resin contains at least one of an aliphatic alkyl group-containing unsaturated monomer having a linear or branched alkyl group having 1 to 18 carbon atoms, an alicyclic alkyl group-containing unsaturated monomer, and an aromatic group-containing unsaturated monomer as constituent units. In one embodiment, the resin contains 80 to 95% by mass of an aliphatic alkyl group-containing unsaturated monomer having a linear or branched alkyl group having 1 to 18 carbon atoms, 80 to 95% by mass of an alicyclic alkyl group-containing unsaturated monomer, 80 to 95% by mass of an aromatic group-containing unsaturated monomer, and 80 to 95% by mass of a crosslinkable monomer, and 2 to 20% by mass of a carboxyl group-containing ethylenically unsaturated monomer as constituent units, based on 100% by mass of total polymerizable monomer.

[0037] In this specification, the term "(meth)acrylic" means both "acrylic" and "methacrylic." Similarly, the term "(meth)acrylate" means both "acrylate" and "methacrylate."

[0038] Examples of aliphatic alkyl-containing unsaturated monomers having linear or branched alkyl groups with 1 to 18 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, n-amyl (meth)acrylate, i-amyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate. These may be used individually or in combination of two or more. The linear or branched aliphatic alkyl group-containing unsaturated monomer having 1 to 18 carbon atoms is preferably methyl methacrylate.

[0039] In one embodiment, the content of a linear or branched aliphatic alkyl group-containing unsaturated monomer having 1 to 18 carbon atoms is 80 to 95% by mass, preferably 85 to 95% by mass, based on 100% by mass of the total polymerizable monomer.

[0040] Examples of alicyclic alkyl group-containing unsaturated monomers include cyclohexyl (meth)acrylate and pt-butylcyclohexyl (meth)acrylate. These may be used individually or in combination of two or more. The alicyclic alkyl group-containing unsaturated monomer is preferably cyclohexyl methacrylate.

[0041] In one embodiment, the content of the alicyclic alkyl group-containing unsaturated monomer is 80 to 95% by mass, preferably 85 to 95% by mass, based on 100% by mass of the total polymerizable monomer.

[0042] Examples of aromatic group-containing unsaturated monomers include styrene, methylstyrene, chlorostyrene, methoxystyrene, α-methylstyrene, p-nitrostyrene, ethyl vinylbenzene, vinyl naphthalene, benzyl acrylate, benzyl methacrylate, phenylethyl acrylate, phenylethyl methacrylate, phenylpropyl acrylate, phenylpropyl methacrylate, phenyl nonyl acrylate, and phenyl nonyl methacrylate. These may be used individually or in combination of two or more. The aromatic group-containing unsaturated monomer is preferably styrene.

[0043] In one embodiment, the content of the aromatic group-containing unsaturated monomer is 80 to 95% by mass, preferably 85 to 95% by mass, based on 100% by mass of the total polymerizable monomer.

[0044] The functional unsaturated monomer is a monomer copolymerizable with the hydrophobic group-containing unsaturated monomer described above. The resin according to one embodiment contains, as a functional ethylenically unsaturated monomer, at least one of the following as constituent units: a carboxyl group-containing ethylenically unsaturated monomer, a hydroxyl group-containing ethylenically unsaturated monomer, an amino group-containing ethylenically unsaturated monomer, an amide group-containing ethylenically unsaturated monomer, and a sulfonic acid group-containing unsaturated monomer. The functional unsaturated monomer is preferably a carboxyl group-containing ethylenically unsaturated monomer.

[0045] Here, if the resin of the functional particles has carboxyl groups, these carboxyl groups tend to be located on the surface of the resin. When carboxyl groups are present on the resin surface, the electrostatic repulsive force between the carboxyl groups that occurs between the functional particles improves the dispersion stability of the functional particles.

[0046] Examples of functional unsaturated monomers include carboxyl group-containing ethylenically unsaturated monomers such as monomers obtained by reacting hydroxyalkyl (meth)acrylates such as (meth)acrylic acid, acrylic acid dimer, 2-hydroxyethyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate with maleic anhydride, succinic anhydride, and phthalic anhydride; hydroxyethyl acrylate, hydroxyethyl methacrylate, 2-hydroxyethyl (meth)acrylate, 2-(3-)hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycero Examples include hydroxyl group-containing ethylenically unsaturated monomers such as hydroxyl mono(meth)acrylate; amino group-containing ethylenically unsaturated monomers such as 2-aminoethyl(meth)acrylate, 2-dimethylaminoethyl(meth)acrylate, 2-aminopropyl(meth)acrylate, and 2-butylaminoethyl(meth)acrylate; amide group-containing ethylenically unsaturated monomers such as (meth)acrylamide, N-methylolacrylamide, and N-butoxymethyl(meth)acrylamide; and sulfonic acid group-containing monomers such as sodium vinylsulfonate and sodium styrenesulfonate. These may be used individually or in combination of two or more. The unsaturated monomer having a functional group is preferably a carboxyl group-containing ethylenically unsaturated monomer. The carboxyl group-containing ethylenically unsaturated monomer is preferably methacrylic acid.

[0047] In one embodiment, the content of the unsaturated monomer having a functional group is 2 to 20% by mass, 3 to 16% by mass, preferably 3 to 14% by mass, based on 100% by mass of the total polymerizable monomer.

[0048] A crosslinkable monomer is a monomer (i.e., a polyfunctional monomer) having two or more polymerizable double bonds that can crosslink a resin. Examples of crosslinkable monomers include allyl (meth)acrylate, ethylene glycol dimethacrylate, ethylene glycol diacrylate, butanediol diacrylate, butanediol dimethacrylate, neopentyl glycol dimethacrylate, hexanediol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetramethacrylate, and divinylbenzene. These may be used individually or in combination of two or more. The crosslinkable monomer is preferably trimethylolpropane trimethacrylate.

[0049] In one embodiment, the content of the crosslinkable monomer is 80 to 95% by mass, preferably 85 to 95% by mass, based on 100% by mass of the total polymerizable monomer. When the resin contains the above predetermined amount of crosslinkable monomer, the solvent resistance of the resin can be further enhanced, and swelling of the resin in the solvent can be suppressed. Solvent resistance refers to the difficulty of functional substances leaching out of the resin.

[0050] <Method for manufacturing functional particles> A method for producing functional particles having a core-shell structure, comprising a core made of a functional substance and a resin shell covering the core, will be described. In one embodiment, the method for producing functional particles includes the steps of: generating a core by stirring a mixture of a functional substance dissolved in a solvent, to which a surfactant and an aqueous dispersion medium have been added; and generating a resin shell covering the core by polymerizing a polymerizable monomer in the presence of the core. The method for producing functional particles having a core-shell structure includes the steps of: generating fine particles of the functional substance that will become the core (hereinafter also referred to as "seed particles") (hereinafter also referred to as the first step); and polymerizing the resin that will become the shell (hereinafter also referred to as the second step). According to the method for producing functional particles of the present invention, functional particles with a sharp particle size distribution can be obtained, and the recovery rate of the solid content of the functional particles can be improved. As the functional particles of the present invention are as described above, a detailed description of the functional particles will be omitted.

[0051] <1st process> The first step (the step of generating seed particles) includes the steps of dissolving a functional substance in a solvent (hereinafter also referred to as the first A step), stirring a mixture in which a surfactant and an aqueous dispersion medium have been added to the functional substance solution (hereinafter also referred to as the first B step), and removing the solvent from the mixture (hereinafter also referred to as the first C step).

[0052] In step 1A, the solvent used to dissolve the functional substance is an organic solvent. Examples of organic solvents include ethers such as ethyl ether and isopropyl ether; alcohols such as methanol and ethanol; methylene chloride; ethylene dichloride; chloroform; carbon tetrachloride; ethyl acetate; methyl ethyl ketone; cyclohexane; cyclopentane; tetrahydrofuran (THF); toluene; hexane; and heptane. These may be used individually or in combination of two or more. The solvent is preferably ethyl acetate.

[0053] In step 1B, a surfactant is used to atomize the functional substance in an aqueous dispersion medium. The surfactant includes, for example, anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. These may be used individually or in combination of two or more. The surfactant is preferably anionic.

[0054] Examples of anionic surfactants include fatty acid salts such as sodium stearate, alkyl sulfate salts such as sodium lauryl sulfate, polyoxyalkylene alkyl ether sulfate salts such as sodium polyoxyethylene alkyl ether sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, sodium dialkyl sulfosuccinate, sodium alkyldiphenyl ether disulfonate, and ammonium polyoxyalkylene alkenyl ether sulfate. These may be used individually or in combination of two or more.

[0055] Examples of cationic surfactants include alkyltrimethylammonium salts, alkyltriethylammonium salts, dialkyldimethylammonium salts, dialkyldiethylammonium salts, and N-polyoxyalkylene-N,N,N-trialkylammonium salts. These may be used individually or in combination of two or more.

[0056] Examples of amphoteric surfactants include alkyldimethylamine oxide and alkylcarboxybetaine. These may be used individually or in combination of two or more.

[0057] Examples of nonionic surfactants include polyoxyethylene alkyl ethers [polyoxyethylene lauryl ether (Kao Corporation, Emulgen 109P, cloud point 83°C, HLB 13.6), polyoxyethylene isodecyl ether (Daiichi Kogyo Seiyaku Co., Ltd., Neugen SD-80, cloud point 80°C, HLB 14.3), polyoxyalkylene branched decyl ether (Daiichi Kogyo Seiyaku Co., Ltd., Neugen XL-100, cloud point 79°C, HLB 14.7), polyoxyethylene tridecyl ether (Daiichi Kogyo Seiyaku Co., Ltd., Neugen TDS-80, cloud point 60°C, HLB 13.3), polyoxyalkylene tridecyl ether (Daiichi Kogyo Seiyaku Co., Ltd., Neugen TDX-50, cloud point 37] Examples include polyoxyethylene C6-20 alkyl ethers such as polyoxyethylene oleyl ether (Kao Corporation, Emulgen 409PV, cloud point 55°C, HLB 12.0), polyoxyethylene styrene-phenyl ether (Daiichi Kogyo Seiyaku Co., Ltd., Neugen EA-137, cloud point 65°C, HLB 13.0), and polyoxyethylene C6-20 alkylene alkenyl ethers having at least one ethylenically unsaturated group (polymerizable unsaturated compound) such as an allyl group (Kao Corporation, Latemul PD-420, cloud point 83°C, HLB 12.6), (Kao Corporation, Latemul PD-430, cloud point 95°C, HLB 14.4). These may be used individually or in combination of two or more.

[0058] In step 1B, examples of aqueous dispersion media include pure water and deionized water. These may be used individually or in combination of two or more. The aqueous dispersion media is preferably deionized water.

[0059] In step 1B, existing microemulsification techniques and subcritical water emulsification techniques can be used to stir the mixture. Existing microemulsification techniques include rotary stirring devices using stirring blades, ultrasonic homogenizers, and high-pressure homogenizers. The means for stirring the mixture is preferably an ultrasonic homogenizer.

[0060] In step 1C, methods for removing the solvent from the mixture include, for example, heating and stirring in a water bath and using a vacuum distillation apparatus.

[0061] <Second process> The second step (the step for generating functional particles) includes a step of generating a resin shell that covers a core by polymerizing a polymerizable monomer in the presence of a core made of a functional material (hereinafter also referred to as the second step A), and a step of extracting functional particles with a predetermined average particle size from the functional particles using centrifugation (hereinafter also referred to as the second step B).

[0062] Methods for synthesizing the resin include, for example, emulsion polymerization, miniemulsion polymerization, and microemulsion polymerization. In step 2A, the method for synthesizing the resin is preferably emulsion polymerization, and more preferably seed emulsion polymerization.

[0063] Any polymerization initiator that has the ability to initiate radical polymerization is acceptable, and conventionally known polymerization initiators can be used.

[0064] Examples of polymerization initiators include persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate; and oils such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile. Soluble azo compounds; 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, 2,2'-azobis{2-methyl-N-[2-(1-hydroxyethyl)]propionamide}, 2,2'-azobis{2-methyl-N-[2-(1-hydroxybutyl)]propionamide}, 2,2'-azobis[2-(5-methyl-2-imidazoline-2-yl) 2,2'-Azobis[2-(2-imidazolin-2-yl)propane] and its salts, 2,2'-Azobis[2-(3,4,5,6-tetrahydropyrimidine-2-yl)propane] and its salts, 2,2'-Azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane} and its salts, 2,2'-Azobis(2-methylpropionamidine) and its salts, Examples include water-soluble azo compounds such as 2,2'-azobis(2-methylpropyneamidine) and its salts, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] and its salts; and organic peroxides such as benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, t-butyl peroxy-2-ethylhexanoate, and t-butyl peroxyisobutyrate. These may be used individually or in combination of two or more.

[0065] In step 2B, for example, functional particles having a predetermined average particle size can be extracted from the functional particle emulsion using an ultracentrifuge. By performing step 2B, monodisperse functional particles with a sharp particle size distribution can be obtained, and impurities other than functional particles can be removed. The ultracentrifuge is just one example of a means for extracting functional particles, and is not limited to this.

[0066] A method for producing functional particles according to one embodiment includes a step of generating a resin shell that covers a core by polymerizing a polymerizable monomer in the presence of a core made of a functional material.

[0067] A method for producing functional particles according to one embodiment further includes the step of generating a core by stirring a mixture in which a surfactant and an aqueous dispersion medium are added to a functional substance dissolved in a solvent.

[0068] A method for producing functional particles according to one embodiment further includes a step of removing a solvent after the step of generating a core.

[0069] A method for producing functional particles according to one embodiment further includes, after the step of generating a shell portion, a step of extracting functional particles of a predetermined average particle size from the functional particles using centrifugation.

[0070] The solvent according to one embodiment includes an organic solvent.

[0071] One embodiment of the surfactant includes an anionic surfactant. The content of the surfactant according to one embodiment is 0.5 to 10 parts by mass per 100 parts by mass of resin.

[0072] <Manufacturing of functional particles> Table 1 shows the raw material formulations and test results for the functional substance microparticles (hereinafter referred to as seed particles) of Production Examples 1 to 8. Table 2 shows the raw material formulations and test results for the functional particles of Examples 1 to 8 and Comparative Examples 1 to 5.

[0073] [Table 1] (Explanation of abbreviations) • Ultrasonic homogenizer (Mitsui Electric Precision Co., Ltd.: UX-600 model, stirring conditions: frequency 20kHz) • Average particle size (nm): The measurement method is as described in Test 1 below. • Seed particle concentration (%): Solid content concentration (%) of seed particles emulsified and dispersed in water. • Stability of seed particles: The method for confirming this is described in Test 2 below.

[0074] [Table 2] (Explanation of abbreviations) ·ST: Styrene MMA: Methyl methacrylate CHMA: Cyclohexyl methacrylate TMP: Trimethylolpropane trimethacrylate • mAAc: Methacrylic acid • Tackifire A: Hydrogenated rosin ester ester gum H manufactured by Arakawa Chemical Industries. Softening point 68-78°C (biomass content 95-100%) • Tackifire B: Polymerized rosin ester Pencel D-135 manufactured by Arakawa Chemical Industries. Softening point 130-140°C (biomass content 80-94%) • Tackifire C: Tamanol 901, a terpene phenol resin manufactured by Arakawa Chemical Industries. Softening point 125-135°C (biomass content 65-79%) • Polylactic acid A: Amorphous polylactic acid resin manufactured by Saiden Chemical Co., Ltd. Tg 47.5℃ (biomass content 95-100%) • Latent heat storage material A: NOF Corporation Butyl stearate (butyl ester stearate) Melting point 23℃ • Latent heat storage material B: Methyl stearate 95 (methyl stearate ester) manufactured by NOF Corporation Melting point 39°C • Fluorescent dye A: Tetraphenylethylene manufactured by Tokyo Chemical Industry Co., Ltd. • Fluorescent dye B: Anthracene manufactured by Tokyo Chemical Industry Co., Ltd. • Aggregation: Indicates that the test could not be conducted due to the formation of aggregates of the functional substance. • Average particle size (nm): The measurement method is as described in Test 1 below. • Theoretical particle concentration (%) of functional substance: Represents the concentration of the functional substance in 100% by mass of functional particles (calculated concentration based on the following formula). Theoretical particle concentration (%) of functional substance = 100 × parts of functional substance / (parts of functional substance + parts of total monomers) • Presence or absence of extraparticle deposition of functional substances: The method for confirmation is as described in Test 3 below. • Stability of functional particles: The method for confirming this is as described in Test 2 below.

[0075] <Manufacturing Example 1: Preparation of Seed Particle Dispersion> A dispersion of functional substances (seed particle dispersion) was prepared using the following procedure (see Table 1). (1) 2.0 parts of the functional substance (Tackifier A) and 10 parts of ethyl acetate were added to a 100 ml glass container and stirred with a magnetic stirrer for 30 minutes. This obtained a solution of the functional substance. (2) To the functional substance solution, 20 parts of deionized water and 0.02 parts of sodium dodecylbenzenesulfonate as an anionic surfactant were added and the mixture was emulsified (micronized) using an ultrasonic homogenizer. This yielded an emulsion in which the functional substance was dissolved. (3) No precipitate was observed after the emulsion was allowed to stand, and no functional substances precipitated. Furthermore, by removing ethyl acetate using a vacuum distillation apparatus, a seed particle dispersion with an average particle size (D50) of 252 nm consisting of 10% tackifier A was prepared.

[0076] <Manufacturing Example 2: Preparation of Seed Particle Dispersion> Only the differences from Manufacturing Example 1 will be explained. Steps (1) to (3) correspond to steps (1) to (3) of Manufacturing Example 1. (1) 2.0 parts of a functional substance (Tackifier B) was added. (2) This is the same as Manufacturing Example 1, so the explanation is omitted. (3) No precipitate was observed after the emulsion was allowed to stand, and no functional substances precipitated. Furthermore, by removing ethyl acetate using a vacuum distillation apparatus, a seed particle dispersion with an average particle size (D50) of 182 nm consisting of 10% tackifier B was prepared.

[0077] <Manufacturing Example 3: Preparation of Seed Particle Dispersion> Only the differences from Manufacturing Example 1 will be explained. (1) to (3) correspond to (1) to (3) of Manufacturing Example 1. (1) 2.0 parts of a functional substance (Tackifier C) was added. (2) This is the same as Manufacturing Example 1, so the explanation is omitted. (3) No precipitate was observed after the emulsion was allowed to stand, and no functional substances precipitated. Furthermore, by removing ethyl acetate using a vacuum distillation apparatus, a seed particle dispersion with an average particle size (D50) of 215 nm consisting of 10% tackifier C was prepared.

[0078] <Manufacturing Example 4: Preparation of Seed Particle Dispersion> Only the differences from Manufacturing Example 1 will be explained. (1) to (3) correspond to (1) to (3) of Manufacturing Example 1. (1) 1.0 part of a functional substance (polylactic acid A) was added. (2) This is the same as Manufacturing Example 1, so the explanation is omitted. (3) No precipitate was observed after the emulsion was allowed to stand, and no functional substances precipitated. Furthermore, by removing ethyl acetate using a vacuum distillation apparatus, a seed particle dispersion with an average particle size (D50) of 194 nm consisting of 5% polylactic acid A was prepared.

[0079] <Manufacturing Example 5: Preparation of Seed Particle Dispersion> Only the differences from Manufacturing Example 1 will be explained. (1) to (3) correspond to (1) to (3) of Manufacturing Example 1. (1) 2.0 parts of a functional substance (latent heat storage material A) was added. (2) This is the same as Manufacturing Example 1, so the explanation is omitted. (3) No precipitate was observed after the emulsion was allowed to stand, and no functional substances precipitated. Furthermore, by removing ethyl acetate using a vacuum distillation apparatus, a seed particle dispersion with an average particle size (D50) of 275 nm, consisting of 10% latent heat storage material A, was prepared.

[0080] <Manufacturing Example 6: Preparation of Seed Particle Dispersion> Only the differences from Manufacturing Example 1 will be explained. (1) to (3) correspond to (1) to (3) of Manufacturing Example 1. (1) 2.0 parts of a functional substance (latent heat storage material B) was added. (2) This is the same as Manufacturing Example 1, so the explanation is omitted. (3) No precipitate was observed after the emulsion was allowed to stand, and no functional substances precipitated. Furthermore, by removing ethyl acetate using a vacuum distillation apparatus, a seed particle dispersion with an average particle size (D50) of 234 nm consisting of 10% latent heat storage material B was prepared.

[0081] <Manufacturing Example 7: Preparation of Seed Particle Dispersion> Only the differences from Manufacturing Example 1 will be explained. (1) to (3) correspond to (1) to (3) of Manufacturing Example 1. (1) 0.5 parts of a functional substance (fluorescent dye A) was added. (2) This is the same as Manufacturing Example 1, so the explanation is omitted. (3) No precipitate was observed after the emulsion was allowed to stand, indicating no precipitation of functional substances. Furthermore, by removing ethyl acetate using a vacuum distillation apparatus, a seed particle dispersion with an average particle size (D50) of 185 nm consisting of 2.5% fluorescent dye A was prepared.

[0082] <Manufacturing Example 8: Preparation of Seed Particle Dispersion> Only the differences from Manufacturing Example 1 will be explained. (1) to (3) correspond to (1) to (3) of Manufacturing Example 1. (1) 0.5 parts of a functional substance (fluorescent dye B) was added. (2) This is the same as Manufacturing Example 1, so the explanation is omitted. (3) No precipitate was observed after the emulsion was allowed to stand, indicating no precipitation of functional substances. Furthermore, by removing ethyl acetate using a vacuum distillation apparatus, a seed particle dispersion with an average particle size (D50) of 164 nm consisting of 2.5% fluorescent dye B was prepared.

[0083] <Example 1: Preparation of functional particles> Refer to Table 2. Seed particles with an average particle size (D50) of 252 nm obtained in Production Example 1 were charged into a glass reaction vessel equipped with a stirrer, thermometer, and reflux condenser. The temperature was raised to 80°C and 0.025 parts of potassium persulfate were added while stirring, and a mixture of 0.95 parts of methyl methacrylate and 0.05 parts of methacrylic acid was added dropwise over 30 minutes. After dropwise addition, the mixture was stirred at the same temperature for 3 hours to prepare functional particles with an average particle size (D50) of 265 nm.

[0084] The average particle size of the functional particles obtained by polymerization was determined by dynamic light scattering, as in Production Example 1. Furthermore, when the obtained functional particles were observed using an electron microscope, no aggregates of functional substances other than the functional particles were observed. This confirmed that the functional substances were encapsulated within the resin particles.

[0085] <Example 2: Preparation of functional particles> Only the differences from Example 1 will be explained. Seed particles with an average particle size (D50) of 182 nm obtained in Production Example 2 were charged. 1.8 parts of methyl methacrylate and 0.2 parts of methacrylic acid were used. Functional particles with an average particle size (D50) of 214 nm were prepared.

[0086] <Example 3: Preparation of functional particles> Only the differences from Example 1 will be explained. Seed particles with an average particle size (D50) of 215 nm obtained in Production Example 3 were used. 0.45 parts of styrene and 0.05 parts of methacrylic acid were used. Functional particles with an average particle size (D50) of 218 nm were prepared.

[0087] <Example 4: Preparation of functional particles> Only the differences from Example 1 will be explained. Seed particles with an average particle size (D50) of 194 nm obtained in Production Example 4 were charged. 0.45 parts of cyclohexyl methacrylate and 0.05 parts of methacrylic acid were used. Functional particles with an average particle size (D50) of 207 nm were prepared.

[0088] <Example 5: Preparation of functional particles> Only the differences from Example 1 will be explained. Seed particles with an average particle size (D50) of 275 nm obtained in Production Example 5 were used. 1.8 parts of trimethylolpropane trimethacrylate and 0.2 parts of methacrylic acid were used. Functional particles with an average particle size (D50) of 305 nm were prepared.

[0089] <Example 6: Preparation of functional particles> Only the differences from Example 1 will be explained. Seed particles with an average particle size (D50) of 234 nm obtained in Production Example 6 were used. 0.95 parts of trimethylolpropane trimethacrylate and 0.05 parts of methacrylic acid were used. Functional particles with an average particle size (D50) of 275 nm were prepared.

[0090] <Example 7: Preparation of functional particles> Only the differences from Example 1 will be explained. Seed particles with an average particle size (D50) of 185 nm obtained in Production Example 7 were charged. 0.45 parts of cyclohexyl methacrylate and 0.05 parts of methacrylic acid were used. Functional particles with an average particle size (D50) of 224 nm were prepared.

[0091] <Example 8: Preparation of functional particles> Only the differences from Example 1 will be explained. Seed particles with an average particle size (D50) of 164 nm obtained in Production Example 8 were charged. 0.95 parts of styrene and 0.05 parts of methacrylic acid were used. Functional particles with an average particle size (D50) of 195 nm were prepared.

[0092] <Comparative Example 1: Preparation of Functional Particles> (1) 2.0 parts of the functional substance (Tackifier A) and 20 parts of methyl methacrylate were added to a 100 ml glass container and stirred with a magnetic stirrer for 30 minutes. This was an attempt to dissolve and liquefy the functional substance, but its solubility with methyl methacrylate was poor, and it precipitated, making dissolution difficult.

[0093] <Comparative Example 2: Preparation of Functional Particles> (1) 2.0 parts of the functional substance (tackifier B) and 19 parts of styrene were added to a 100 ml glass container and stirred with a magnetic stirrer for 30 minutes. This obtained a functional substance solution. After dissolution, 1.0 part of methacrylic acid, 40 parts of deionized water, and 0.5 parts of sodium dodecylbenzenesulfonate as an anionic surfactant were added, and the mixture was emulsified with a homogenizer to prepare the emulsion. No precipitation or sedimentation of tackifier B was observed. (2) Forty parts of deionized water were weighed into a glass reaction vessel equipped with a stirrer, reflux condenser, thermometer, and emulsion introduction tube, and the inside of the vessel was purged with nitrogen. Then, while stirring at 80°C, 0.2 parts of potassium persulfate were added, and the emulsion prepared in (1) was added dropwise over 2 hours. Emulsion polymerization was attempted by stirring and aging at the same temperature for 3 hours, but the reaction was unsuccessful, and polymerization inhibition occurred under the dissolution of tackifier B, resulting in unsuccessful acquisition of resin particles.

[0094] <Comparative Example 3: Preparation of Functional Particles> (1) 1.0 part of the functional substance (polylactic acid A) and 19 parts of methyl methacrylate were added to a 100 ml glass container and stirred with a magnetic stirrer for 30 minutes. This obtained a functional substance solution. After dissolution, 1.0 part of methacrylic acid, 40 parts of deionized water, and 0.5 parts of sodium dodecylbenzenesulfonate as an anionic surfactant were added, and the mixture was emulsified with a homogenizer to prepare the emulsion. No precipitation or sedimentation of polylactic acid A was observed. (2) Forty parts of deionized water were weighed into a glass reaction vessel equipped with a stirrer, reflux condenser, thermometer, and emulsion introduction tube, and the inside of the vessel was replaced with nitrogen. Then, while stirring at 80°C, 0.2 parts of potassium persulfate were added, and the emulsion prepared in (1) was added dropwise over 2 hours. The mixture was then stirred and aged at the same temperature for 3 hours to complete the emulsion polymerization. Many aggregates were generated from the resulting emulsion. Most of these were precipitates of polylactic acid A.

[0095] <Comparative Example 4: Preparation of Functional Particles> (1) 2.0 parts of the functional substance (fluorescent dye A) and 20 parts of cyclohexyl methacrylate were added to a 100 ml glass container and stirred with a magnetic stirrer for 30 minutes. This was an attempt to dissolve and liquefy the functional substance, but its solubility in cyclohexyl methacrylate was poor, causing precipitation and making dissolution difficult.

[0096] <Comparative Example 5: Preparation of Functional Particles> (1) 0.5 parts of the functional substance (fluorescent dye B) and 19 parts of styrene were added to a 100 ml glass container and stirred with a magnetic stirrer for 30 minutes. This obtained a functional substance solution. After dissolution, 1.0 part of methacrylic acid, 40 parts of deionized water, and 0.5 parts of sodium dodecylbenzenesulfonate as an anionic surfactant were added, and the mixture was emulsified with a homogenizer to prepare the emulsion. No precipitation or sedimentation of fluorescent dye B was observed. (2) Forty parts of deionized water were weighed into a glass reaction vessel equipped with a stirrer, reflux condenser, thermometer, and emulsion introduction tube, and the inside of the vessel was replaced with nitrogen. Then, while stirring at 80°C, 0.2 parts of potassium persulfate were added, and the emulsion prepared in (1) was added dropwise over 2 hours. Emulsion polymerization was attempted by stirring and aging at the same temperature for 3 hours, but the reaction was unsuccessful, and polymerization inhibition occurred under the dissolution of fluorescent dye B, resulting in unsuccessful acquisition of resin particles.

[0097] <Testing Method> Tests 1 and 2 were conducted using the seed particles from Manufacturing Examples 1 to 8. Tests 1 to 3 were conducted using the functional particles from Examples 1 to 8 and Comparative Examples 1 to 5. This allowed for the evaluation of the performance of the seed particles and functional particles.

[0098] (Test 1: Measurement of average particle size) The average particle size (D50) of seed particles and functional particles was measured using a particle size analyzer (Otsuka Electronics Co., Ltd., FPAR-1000).

[0099] (Test 2: Confirmation of particle stability) The stability of the prepared seed particles and functional particles was evaluated by checking for separation and sedimentation after standing at room temperature for 24 hours. [Evaluation Criteria] ○: Good stability (in the case of no separation or sedimentation) ×: Poor stability (if separation and sedimentation occur)

[0100] (Test 3: Presence or absence of extraparticle deposition of functional substances) A dispersion of functional particles was collected and dried at 23°C for 1 hour. Then, a scanning electron microscope (SEM) manufactured by JEOL was used to confirm whether functional substances were present outside the functional particles. [Evaluation Criteria] ○: Functional substances are not present outside of the functional particles. ×: Functional material exists outside of functional particles.

[0101] <Test Results> The test results for Examples 1-8 and Comparative Examples 1-5 will be described with reference to Table 2 above. Figure 1 shows an example of an SEM image of seed particles according to one embodiment. Figure 2 shows an example of an SEM image of functional particles according to one embodiment.

[0102] Examples 1-8 demonstrate successful encapsulation of each functional substance within resin particles at high concentrations. In Figure 1, there were no aggregates of functional substances other than the seed particles. Similarly, in Figure 2, there were no aggregates of functional substances other than the functional particles. Thus, Examples 1-8 demonstrate that there is no loss of functional substances throughout the entire process, both the pre-process (seed particle manufacturing process) and the post-process (functional particle manufacturing process). In other words, the relationship between the calculated concentration of the functional substance and the actual concentration of the functional substance within the functional particles holds true.

[0103] In Comparative Examples 1-5, each functional substance was fabricated using conventional emulsion polymerization, but it was not possible to encapsulate them in resin particles at the high concentrations shown in the Examples. Specifically, in Comparative Example 1, the functional substance (tackifier A) had low solubility in the monomer (methyl methacrylate), making high-concentration dissolution difficult. In Comparative Example 2, although solubility could be improved by using styrene, which has a similar structure to the functional substance (tackifier B), polymerization inhibition occurred when conventional emulsion polymerization was performed, resulting in poor reaction and the inability to obtain functional particles. In Comparative Example 3, the functional substance (polylactic acid A) could be dissolved in the monomer (methyl methacrylate), but aggregates formed when conventional emulsion polymerization was performed, and most of the functional substance precipitated outside the particles. Furthermore, in Comparative Example 4, the functional substance (fluorescent dye A) had low solubility in the monomer (cyclohexyl methacrylate), precipitated, and could not be dissolved. In Comparative Example 5, the functional substance (fluorescent dye B) could be dissolved in the monomer (styrene), but polymerization inhibition occurred during emulsion polymerization, resulting in a poor reaction and the inability to obtain functional particles.

[0104] According to the test results, the conventional methods shown in Comparative Examples 1-5 were unable to increase the concentration of functional substances within the functional particles. Furthermore, the storage stability of the functional particles in Comparative Examples 1-5 was very poor.

[0105] The main reason for this is the low solubility of the functional substance in the monomer. Furthermore, even if dissolution is possible, conventional polymerization methods result in polymerization inhibition, leading to poor reaction and the inability to obtain the desired functional particles. Therefore, in the comparative example, it is not possible to increase the concentration of the functional substance within the functional particles.

[0106] As explained at the beginning of this specification, the conditions for fully exhibiting the various functions of a functional substance are to prevent the loss of the functional substance within the functional particles and to increase the concentration of the functional substance. However, as stated above, the methods for producing functional particles in Comparative Examples 1 to 5 cannot satisfy this condition. On the other hand, the method for producing functional particles of the present invention can fully satisfy this condition.

[0107] As described above, the present invention has the remarkable effect of improving the storage stability of functional particles. Furthermore, the present invention can increase the concentration of functional substances by preventing the loss of functional substances during the manufacturing process of functional particles. As a result, the present invention can provide high-quality functional particles that can fully exhibit the various functions of the functional substances.

[0108] The invention is not limited to the embodiments described above, and various modifications and changes are possible within the scope of the gist of the invention.

Claims

1. Functional particles with a core-shell structure, A core made of a functional material, It comprises a resin shell portion that covers the core portion, The core portion is made of nanoparticles. Functional particles.

2. The average particle diameter of the core portion is 50 to 500 nm. The average particle size of the functional particles is 60 to 1000 nm. Here, the average particle diameter of the core portion and the average particle diameter of the functional particles are the particle diameters that represent 50% of the cumulative particle size distribution measured by dynamic light scattering (D50; median diameter). Functional particles according to claim 1.

3. The functional particles contain 5 to 95% by mass of the functional substance in 100% by mass of the functional particles. Functional particles according to claim 1.

4. The resin comprises at least one of the following as constituent units: an aliphatic alkyl group-containing unsaturated monomer having a linear or branched alkyl group having 1 to 18 carbon atoms, an alicyclic alkyl group-containing unsaturated monomer, an aromatic group-containing unsaturated monomer, and a crosslinkable monomer. Functional particles according to claim 1.

5. The resin contains at least one of the following as constituent units: a carboxyl group-containing ethylenically unsaturated monomer, a hydroxyl group-containing ethylenically unsaturated monomer, an amino group-containing ethylenically unsaturated monomer, an amide group-containing ethylenically unsaturated monomer, and a sulfonic acid group-containing unsaturated monomer. Functional particles according to claim 1.

6. The resin comprises, with respect to 100% by mass of a total polymerizable monomer, 80 to 95% by mass of an aliphatic alkyl group-containing unsaturated monomer having a linear or branched alkyl group with 1 to 18 carbon atoms, 80 to 95% by mass of an alicyclic alkyl group-containing unsaturated monomer, 80 to 95% by mass of an aromatic group-containing unsaturated monomer, and 80 to 95% by mass of a crosslinkable monomer, and 2 to 20% by mass of a carboxyl group-containing ethylenically unsaturated monomer as constituent units. Functional particles according to claim 1.

7. The carboxyl group-containing ethylenically unsaturated monomer is methacrylic acid. Functional particles according to claim 6.

8. The aliphatic alkyl-containing unsaturated monomer having a linear or branched alkyl group having 1 to 18 carbon atoms is methyl methacrylate. Functional particles according to claim 6.

9. The aforementioned alicyclic alkyl group-containing unsaturated monomer is cyclohexyl methacrylate. Functional particles according to claim 6.

10. The aforementioned aromatic group-containing unsaturated monomer is styrene. Functional particles according to claim 6.

11. The aforementioned crosslinkable monomer is trimethylolpropane trimethacrylate. Functional particles according to claim 6.

12. The functional substance is one of the following: tackifier, polylactic acid, latent heat storage material, and functional dye. Functional particles according to any one of claims 1 to 11.

13. A method for producing functional particles having a core-shell structure, comprising a core made of a functional material and a resin shell covering the core, A step of generating the core portion by stirring a mixture to which a surfactant and an aqueous dispersion medium have been added to the functional substance dissolved in a solvent, The process includes a step of polymerizing a polymerizable monomer in the presence of the core to produce a resin shell that covers the core, A method for manufacturing functional particles.

14. The process includes, after the step of generating the core portion, a step of removing the solvent, The manufacturing method according to claim 13.

15. The process includes, after the step of generating the shell portion, a step of extracting functional particles with a predetermined average particle size from the functional particles using centrifugal separation. The manufacturing method according to claim 13.

16. The aforementioned solvent includes an organic solvent. The manufacturing method according to claim 13.

17. The aforementioned surfactant is an anionic surfactant. The manufacturing method according to any one of claims 13 to 16.

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