JP2017082045A - Method for producing core-shell particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing core-shell particles of high quality.SOLUTION: Provided is a method for producing core-shell particles using a first oily medium, a second oily medium and an aqueous medium, comprising: a step 1 where the first oily medium flowing through a first microchannel and the second oily medium flowing through a second microchannel are joined at a first joining point; and a step 2 where the first oily medium and second oily medium flowing through a third microchannel on the downstream side from the first joining point are discharged into the aqueous medium to form core-shell particles. In the case each interface tension between the first oily medium and the second oily medium, between the first oily medium and the aqueous medium and between the second oily medium and the aqueous medium is defined as γ1,γ2 and γ3, the value of the γ1, γ2 and γ3 satisfies inequalities (1) to (3); (1):0>γ1-(γ2+γ3), (2):0<γ2-(γ1+γ3)<151 and (3):0>γ3-(γ1+γ2).SELECTED DRAWING: None

Description

  The present invention relates to a method for producing core-shell particles.

  Core-shell particles formed of different materials for the core and shell are used as microcapsules that encapsulate a specific substance in the core, or as multi-layered particles with functionality on the surface. Its application fields cover a wide range of fields such as pharmaceuticals, cosmetics, foods, electronic materials, and adhesives.

  As a conventional method for producing core-shell particles, a core-shell particle is produced in which the core-particulate particles are coated with a polymer that forms the shell part by polymerizing the monomer that becomes the shell part in the presence of the core-particulate particles. The method of making it is common. However, the core-shell particles produced by this production method have a problem in that the particle diameter varies, and the monomer that becomes the shell part does not cover the surface of the particle that becomes the core part, and becomes a single particle. It was.

  Therefore, in recent years, monodispersed core-shell particles using a glass or metal substrate (hereinafter sometimes referred to as a microchip) having microchannels (microchannels) having a width and depth of several μm to several hundred μm. A method for producing the material has been studied.

  For example, in patent document 1, two manufacturing methods are shown as a manufacturing method of the core-shell particle using a microchip.

  In the first manufacturing method, the first dispersed phase and the second dispersed phase are respectively supplied from the direction perpendicular to the flow to the continuous phase flowing in the continuous phase flow path, and upstream of the continuous phase flow path. The first dispersed phase supplied from the side is transmitted to the wall surface of the continuous phase flow path and merged with the second dispersed phase supplied from the downstream side of the continuous phase flow path to form a two-phase flow, using the flow of the continuous phase Droplets are generated from a two-phase flow to produce core-shell droplets having the first dispersed phase as the shell portion and the second dispersed phase as the core portion.

  However, in the first manufacturing method, when the supply speed of the dispersed phase and the continuous phase is increased, the first dispersed phase does not travel along the wall surface of the continuous phase flow path, and the first dispersed phase and the second dispersed phase are single droplets. Therefore, there is a problem that the feed rate of the dispersed phase and the continuous phase must be reduced at the expense of productivity.

  In the second manufacturing method, first, when the core is the core, the first dispersed phase droplets are discharged into the second dispersed phase as the shell, and then the second dispersed phase containing the first dispersed phase droplets is contained. By discharging the droplets into the continuous phase, core-shell droplets having the first dispersed phase as the core portion and the second dispersed phase as the shell portion are manufactured.

  However, in the second manufacturing method, the number of droplets in the first dispersed phase contained varies, so that core-shell droplets having different core thicknesses are generated. There is a problem that single droplets of the second dispersed phase are generated by discharging the droplets of the second dispersed phase that are not encapsulated into the continuous phase.

  Also, for example, in Patent Document 2, the first dispersed phase and the second dispersed phase colored with different colorants are supplied from different dispersed phase flow paths and merged, and continuously in the form of a two-layer flow incompatible with each other. A method for producing colored spherical polymer particles separated into two colors by discharging into a phase and making it spherical is shown. However, the production of core-shell particles using these methods is not mentioned.

International Publication No. 2002/068104 JP 2004 197083 A

  The main object of the present invention is to provide a method for efficiently producing high-quality core-shell particles using microchannels.

The present inventors diligently studied to solve the above problems. As a result, the first oil medium that flows through the first microchannel and the second oil medium that flows through the second microchannel are merged at the first merge point of the first microchannel and the second microchannel, and 1, the first oily medium and the second oily medium flowing through the third microchannel continuing downstream from the first confluence are discharged into the aqueous medium, the first oily medium being the core portion, and the second oily medium being And the step 2 of forming the core-shell particles constituting the shell portion, wherein the interfacial tension between the first oil medium and the second oil medium is γ1, and the interfacial tension between the first oil medium and the aqueous medium is The first oily medium and the second oily medium in which the values of γ1, γ2, and γ3 satisfy the following formulas (1) to (3) when γ2 and the interfacial tension between the second oily medium and the aqueous medium is γ3 And aqueous media By manufacturing the shell particles were found to be able to produce a high quality core-shell particles efficiently.
Formula (1): 0> γ1- (γ2 + γ3)
Formula (2): 0 <γ2- (γ1 + γ3) <151
Formula (3): 0> γ3- (γ1 + γ2)
That is, the present invention provides the following method for producing core-shell particles.
Item 1. A step 1 of joining a first oily medium flowing through the first microchannel and a second oily medium flowing through the second microchannel at a first confluence of the first microchannel and the second microchannel;
Subsequent to the step 1, the first oil medium and the second oil medium flowing through the third microchannel continuing downstream from the first merge point are discharged into an aqueous medium, and the first oil medium is a core portion. Step 2 for forming core-shell particles, wherein the second oily medium constitutes a shell part;
With
The interfacial tension between the first oily medium and the second oily medium is γ1, the interfacial tension between the first oily medium and the aqueous medium is γ2, and the interface between the second oily medium and the aqueous medium is Using the first oily medium, the second oily medium, and the aqueous medium in which the values of γ1, γ2, and γ3 satisfy the following formulas (1) to (3) when the tension is γ3, Production method.
Formula (1): 0> γ1- (γ2 + γ3)
Formula (2): 0 <γ2- (γ1 + γ3) <151
Formula (3): 0> γ3- (γ1 + γ2)
Item 2. Item 2. The method for producing core-shell particles according to Item 1, wherein the first oily medium and the second oily medium each contain a polymer or a monomer.
Item 3. Item 3. The method for producing core-shell particles according to Item 1 or 2, wherein the first oily medium contains silicone, and the second oily medium contains polyimide.
Item 4. Item 4. The method for producing core-shell particles according to Item 2 or 3, wherein at least one of the first oily medium and the second oily medium further contains a curing agent.
Item 5. Item 5. The method for producing core-shell particles according to any one of Items 1 to 4, wherein the aqueous medium contains polyvinyl alcohol.
Item 6. The third microchannel, the fourth microchannel in which the aqueous medium flows, and the fifth microchannel in which the aqueous medium flows in a portion where the first oily medium and the second oily medium are discharged into the aqueous medium. Item 6. The method for producing core-shell particles according to any one of Items 1 to 5, further comprising a second merge point where the channel merges.
Item 7. In the second confluence, the flow direction of the aqueous medium flowing through the fourth microchannel and the flow direction of the aqueous medium flowing through the fifth microchannel form an angle of 180 ° or less. Item 7. The method for producing core-shell particles according to Item 6, wherein the aqueous medium flowing through 4 microchannels and the aqueous medium flowing through the fifth microchannel merge.
Item 8. Item 8. The method for producing core-shell particles according to Item 7, comprising a step 3 for curing the core-shell particles after the step 2.
Item 9. Item 9. The method for producing core-shell particles according to Item 8, comprising the step 3-1 of curing the core-shell particles in the aqueous medium in the step 3.
Item 10. Item 9. The method for producing core-shell particles according to Item 8, comprising the step 3-2 of curing the core-shell particles after separating the core-shell particles and the aqueous medium in the step 3.
Item 11. Step 3-1 in which the core-shell particles are cured in the aqueous medium in the step 3, and the core-shell particles cured in the step 3-1 are separated from the aqueous medium, and then the core-shell particles are cured 3- Item 9. The method for producing core-shell particles according to Item 8, comprising 2;

  ADVANTAGE OF THE INVENTION According to this invention, the method of manufacturing a good quality core-shell particle efficiently using a microchannel can be provided.

It is a schematic diagram for demonstrating the manufacturing method of the core-shell particle of this invention. It is a schematic diagram of the microchannel formed in the microchip used by the Example and comparative example of this invention. It is a schematic sectional drawing of the core-shell particle obtained by the manufacturing method of this invention. It is a schematic sectional drawing of the electroconductive particle manufactured using the core-shell particle obtained by the manufacturing method of this invention. 2 is a photograph of a second confluence point Q of microchannels taken in Example 1. FIG. 6 is a photograph of a second confluence point Q of microchannels taken in Comparative Example 1. FIG. It is another example of the schematic diagram of the microchannel formed in the microchip used for the manufacturing method of the core-shell particle of this invention.

The method for producing core-shell particles of the present invention includes at least the following steps 1 and 2.
Step 1: The first oily medium flowing through the first microchannel and the second oily medium flowing through the second microchannel are merged at the first merge point of the first microchannel and the second microchannel.
Step 2: Subsequent to Step 1, the first oily medium and the second oily medium flowing through the third microchannel continuing downstream from the first joining point are discharged into the aqueous medium, and the first oily medium is the core part, The second oily medium forms core-shell particles that constitute the shell portion.
Further, in the present invention, in addition to the provision of the steps 1 and 2, the interfacial tension γ1 between the first oily medium and the second oily medium, and the interfacial tension γ2 between the first oily medium and the aqueous medium. The first oily medium, the second oily medium, and the aqueous medium satisfying the following expressions (1) to (3) are used as the interfacial tension γ3 between the second oily medium and the aqueous medium. .
Formula (1): 0> γ1- (γ2 + γ3)
Formula (2): 0 <γ2- (γ1 + γ3) <151
Formula (3): 0> γ3- (γ1 + γ2)

  In the three-component system in which the first oily medium, the second oily medium, and the aqueous medium are present, the formula (1) means that the first oily medium and the second oily medium have predetermined wettability. Yes. Similarly, formula (3) means that the second oily medium and the aqueous medium have predetermined wettability. Furthermore, Formula (2) means that the first oily medium and the aqueous medium are difficult to spread.

  In general, when a two-phase liquid medium composed of a first oil medium and a second oil medium is discharged into an aqueous medium, the droplet shape is such that the surface free energy of the first oil medium and the second oil medium is minimized. Changes. For example, when the first oily medium and the second oily medium form separate droplets, respectively, the two-phase liquid medium droplets form hemispherical droplets of the first oily medium and the second oily medium. When forming the connected droplets, it is conceivable that one of the first oily medium and the second oily medium forms a core-shell structure droplet in which a core portion is formed and the other is a shell portion.

In this invention, what has the said process 1 and the process 2, and satisfy | fills the specific relationship of said Formula (1)-(3) as a 1st oily medium, a 2nd oily medium, and an aqueous medium. By using it, good-quality core-shell particles can be efficiently produced. More specifically, when a two-phase liquid medium composed of a first oil medium and a second oil medium is discharged into an aqueous medium to form spherical particles, At the interface portion with the aqueous medium, the surface free energy is remarkably increased and becomes unstable. At this time, the second oil medium having a predetermined wettability with the first oil medium and the aqueous medium becomes spherical so as to cover the first oil medium, so that the two-phase liquid medium forms a spherical shape. The free surface free energy is reduced and stable particles are produced. That is, core-shell particles in which the first oil-based medium has a core part and the second oil-based medium has a shell part are generated.
Hereafter, the manufacturing method of the core-shell particle of this invention is explained in full detail, referring the schematic diagram of FIG.1, FIG2 and FIG.7.

  In the method for producing core-shell particles of the present invention, a so-called microchannel method is used in which a raw material is supplied into a microchannel (microchannel) formed on a microchip to produce a target product. For example, in the method for producing core-shell particles using the microchannel method, an oily medium that is a raw material for the core part of the core-shell particles and an oily medium that is a raw material for the shell part are supplied to the microchannel, and these are contained in the aqueous medium. The oily medium is discharged into the aqueous medium so that droplets of the oily medium are formed. At this time, the core-shell particles are generated by utilizing the fact that the droplets of the oil-based medium generated in the aqueous medium become spherical particles that minimize the surface free energy of the droplets by their surface tension.

  In the present invention, for example, as shown in FIG. 1, a first oil medium 7 flowing through the first microchannel 1 and a second oil medium 8 flowing through the second microchannel 2 are connected to the first microchannel 1 and the first microchannel 1. Step 1 of joining at the first joining point P of 2 microchannels 2 is performed. Next, following step 1, the first oily medium 7 and the second oily medium 8 flowing through the third microchannel 3 continuing downstream from the first confluence P are discharged into the aqueous medium 9, and the first oily medium is discharged. 7 forms core-shell particles 10 in which the core part and the second oily medium 8 constitute the shell part (step 2).

  In the present invention, in step 1, the first oil medium 7 and the second oil medium 8 merged at the first merge point P flow through the third microchannel 3 in a two-phase state. Next, in step 2, the first oil medium 7 and the second oil medium 8 flowing through the third microchannel 3 are discharged into the aqueous medium 9. At this time, in the present invention, the interfacial tension γ1 between the first oil medium 7 and the second oil medium 8, the interfacial tension γ2 between the first oil medium 7 and the aqueous medium 9, and the second oil medium 8 and the aqueous medium. 9 has a specific relationship of the above formulas (1) to (3), so that in the aqueous medium 9, the first oil medium 7 is the core portion, The core-shell particles 10 in which the oil-based medium 8 constitutes the shell portion are suitably formed, and high-quality core-shell particles can be efficiently produced.

In the present invention, from the viewpoint of efficiently producing good-quality core-shell particles, γ1 to γ3 satisfy the relationship of the above formulas (1) and (3), and further, the following formulas (1a) and ( It is preferable that the relationship 3a) is satisfied.
Formula (1a): 0> γ1- (γ2 + γ3)> − 160
Formula (3a): 0> γ3- (γ1 + γ2)> − 160

  In the present invention, the composition of the first oily medium 7 and the second oily medium 8 is not particularly limited as long as the specific relationships of the formulas (1) to (3) can be satisfied. From the viewpoint of producing the solid core-shell particles later, it is preferable that each contains a polymer or a monomer (a monomer constituting the polymer). In the present invention, even when the first oil medium 7 and the second oil medium 8 contain a polymer, the core portion formed by the first oil medium 7 and the shell portion formed by the second oil medium 8 are provided. It is possible to efficiently produce the high-quality core-shell particles.

  When the first oily medium 7 includes a polymer, the polymer is not particularly limited, but is preferable from the viewpoint of satisfying the specific relationships of the above formulas (1) to (3) and suitably forming the core portion. Includes silicone (for example, silicone rubber such as solid silicone rubber and liquid silicone rubber). Silicone may be contained as a monomer or oligomer that polymerizes to form a polymer. As silicone, liquid silicone rubber (for example, thermosetting liquid silicone rubber, room temperature curable liquid silicone rubber, etc.) is preferable, and thermosetting liquid silicone rubber is particularly preferable. By using the thermosetting liquid silicone rubber, a liquid state satisfying the specific relationships of the above formulas (1) to (3) can be suitably maintained until the core-shell particles are formed in the aqueous medium 9. Thereafter, the core part can be suitably cured by heating the core-shell particles.

  Commercially available products of thermosetting liquid silicone rubber include, for example, Elastosil LR series (Asahi Kasei Wacker Silicon Co., Ltd.), Semicodyl series (Asahi Kasei Wacker Silicon Co., Ltd.), One-part RTV series (Shin-Etsu Chemical Co., Ltd.), TSE Series (Momentive Performance Materials Japan GK).

  Each of the polymers or monomers contained in the first oily medium 7 may be one kind or a combination of two or more kinds. Although it does not restrict | limit especially as content of the polymer or monomer contained in the 1st oil-based medium 7, From a viewpoint of manufacturing a good quality core-shell particle efficiently, Preferably it is about 35-95 mass%, More preferably, it is 45- About 70 mass% is mentioned.

  Moreover, when the 2nd oil-based medium 8 contains a polymer or a monomer, although it does not restrict | limit especially as a polymer, the viewpoint which satisfies the specific relationship of said Formula (1)-(3), and forms a shell part suitably. Is preferably polyimide. The polyimide may be contained as a monomer that forms a polyimide by polymerization.

  Although it does not restrict | limit especially as a polyimide, It is preferable to use a solvent soluble polyimide. The solvent-soluble polyimide is a polyimide that is soluble in an organic solvent, and preferably soluble in 1% by mass or more in the organic solvent. As the organic solvent, a general organic solvent can be used, and examples thereof include pentane, normal hexane, cyclohexane, cyclohexanone, benzene, toluene, xylene, chloroform, methyl ethyl ketone, and N-methyl-2-pyrrolidone. An organic solvent may be used individually by 1 type and may be used in combination of 2 or more types. By using the solvent-soluble polyimide, a liquid state satisfying the specific relationships of the above formulas (1) to (3) can be suitably maintained until the core-shell particles are formed in the aqueous medium 9.

  Commercially available solvent-soluble polyimides include, for example, the SPIXAREA series (Somar Corporation), the PIAD series (Arakawa Chemical Industry Co., Ltd.), Solpy 6,6-PI (Solpie Industry Co., Ltd.), and the Q-VR / AD series (stock) Examples include solvent-soluble polyimide solutions (solutions dissolved in organic solvents) such as PIA Technical Research Institute.

  Each of the polymers or monomers contained in the second oil medium 8 may be one kind or a combination of two or more kinds. Although it does not restrict | limit especially as content of the polymer or monomer contained in the 2nd oil-based medium 8, From a viewpoint of manufacturing a good quality core-shell particle efficiently, Preferably it is about 5-30 mass%, More preferably, it is 5-5. About 20 mass% is mentioned.

  When the 1st oily medium 7 and the 2nd oily medium 8 contain a polymer or a monomer, respectively, you may further contain the hardening | curing agent. By including the curing agent, the liquid state satisfying the specific relationships of the above formulas (1) to (3) can be suitably maintained until the core-shell particles are formed in the aqueous medium 9, and then the core-shell particles The core portion or the shell portion can be suitably cured by heating.

  The type of curing agent is not particularly limited as long as it can cure the core part and the shell part, and is a commercially available product such as a thermosetting curing agent (thermosetting agent) and a photocurable curing agent (photocuring agent). Can be used. The curing agent described above may be a type that cures by reacting with the polymer or monomer contained in the core portion or the shell portion, a type that reacts and cures with the curing agents, or a type that includes both. For example, when the second oil-based medium 8 includes polyimide, it is preferable to use a thermosetting curing agent as the curing agent, and it is more preferable to use a thermosetting epoxy-based curing agent. As the thermosetting epoxy curing agent, one-pack type or two-pack type commercially available from each manufacturer can be used, but one-pack type is more preferable. As a commercial item of a thermosetting epoxy type hardening | curing agent, a Scotch weld series (3M company), a denatite series (Nagase ChemteX Corporation), a TETRAD series (Mitsubishi Gas Chemical Co., Ltd.), etc. are mentioned, for example. A hardening | curing agent may be used individually by 1 type, and may be used in combination of 2 or more types.

  When the first oily medium 7 contains a curing agent, the content thereof is not particularly limited, but from the viewpoint of efficiently producing good-quality core-shell particles, the polymer or monomer 100 contained in the first oily medium 7 is used. Preferably it is about 0.1-20 mass parts with respect to a mass part, More preferably, about 0.1-10 mass parts is mentioned. In addition, when the second oily medium 8 contains a curing agent, the content thereof is not particularly limited, but from the same viewpoint, it is preferably based on 100 parts by mass of the polymer or monomer contained in the second oily medium 8. Is about 1 to 20 parts by mass, more preferably about 5 to 15 parts by mass.

  Further, each of the first oil medium 7 and the second oil medium 8 may contain an oil solvent. By using the oily solvent, the interfacial tensions γ1 to γ3 can be adjusted depending on the type and blending ratio of the oily solvent, so that the specific relationships of the above formulas (1) to (3) can be easily satisfied. In addition, for example, by using an oily solvent together with the aforementioned polymer, a liquid state satisfying the specific relationships of the above formulas (1) to (3) is preferably maintained until the core-shell particles are formed in the aqueous medium 9. Then, by removing the oily solvent from the core-shell particles, solid core-shell particles can be suitably produced.

  As the oily solvent, a general organic solvent can be used, and examples thereof include pentane, normal hexane, cyclohexane, cyclohexanone, benzene, toluene, xylene, chloroform, methyl ethyl ketone, and N-methyl-2-pyrrolidone. An oil-based solvent may be used individually by 1 type, and may be used in combination of 2 or more types.

  Although it does not restrict | limit especially as content of the oil-based solvent contained in the 1st oil-based medium 7, From a viewpoint of manufacturing a good quality core-shell particle efficiently, Preferably it is about 0-65 mass%, More preferably, it is 5-50. About mass% is mentioned. The content of the oily solvent contained in the second oily medium 8 is not particularly limited, but from the same viewpoint, it is preferably about 70 to 90% by mass, more preferably about 80 to 90% by mass.

  The first oil medium 7 and the second oil medium 8 may each contain other conventional additives (for example, stabilizers such as antioxidants and ultraviolet absorbers). Content of the said additive is not specifically limited, It can adjust suitably.

  In the production method of the present invention, it is particularly preferable that the first oily medium 7 contains silicone and the second oily medium 8 contains polyimide. Thereby, the core part is formed with silicone, and the high quality core-shell particle | grains in which the shell part was formed with the polyimide can be manufactured efficiently. Furthermore, in the production method of the present invention, the above-mentioned oily solvent is used for the first oily medium 7 and the second oily medium 8, and the interfacial tension between the first oily medium 7 and the second oily medium 8 is expressed by the above formula (1). ) To (3) are preferably adjusted so as to satisfy the specific relationship.

  The aqueous medium 9 is not particularly limited as long as it satisfies the specific relationships of the above formulas (1) to (3), but includes, for example, water-soluble components such as polyvinyl alcohol, polyethylene glycol, and polyalkylene oxide. An aqueous solution may be mentioned.

  The water-soluble component is not particularly limited, and those commercially available from various manufacturers can be used. For example, commercially available products of polyvinyl alcohol include the Gohsenol Series (Nippon Gosei Chemical Industry Co., Ltd.), the Poval Series (Kuraray Co., Ltd.), the Poval Series (Nippon Vinegar & Poval Inc.), and the Denka Poval Series (Electrochemical Industry) Etc.). One type of water-soluble component may be used alone, or two or more types may be used in combination.

  In the aqueous medium 9, the content of the water-soluble component contained in the aqueous solution is not particularly limited, but is preferably about 0.1 to 10% by mass, more preferably from the viewpoint of efficiently producing good-quality core-shell particles. Is about 1 to 5% by mass.

  In the production method of the present invention, from the viewpoint of efficiently producing high-quality core-shell particles, the first oily medium 7, the second oily medium 8, and the aqueous medium 9 are particularly preferably composed of the first oily medium 7 and silicone. It is formed of a mixture of oil solvents, the second oil medium 8 is formed of a mixture of polyimide, thermosetting epoxy curing agent and oil solvent, and the aqueous medium is an aqueous solution containing polyvinyl alcohol. .

  In the present invention, core-shell particles having a core portion made of silicone and a shell portion made of a cured product of a composition containing polyimide and a thermosetting epoxy curing agent, the core portion exhibits excellent elasticity, and the shell portion Exhibits excellent heat resistance, solvent resistance, insulation, mechanical properties, etc. From these characteristics, the core-shell particles having such a composition include, in particular, use as an insulating spacer for electronic devices, and conductive metals (for example, copper, silver, gold, palladium, one or more of these) on the surface. It is expected to be used as flexible conductive connector particles by coating an alloy or the like.

  The interfacial tension γ1 between the first oil medium 7 and the second oil medium 8 is not particularly limited as long as the above formulas (1) to (3) are satisfied, but from the viewpoint of efficiently producing good-quality core-shell particles. , Preferably more than 0 mN / m and 10 mN / m or less, more preferably more than 0 mN / m and 5 mN / m or less. Further, the interfacial tension γ2 between the first oil medium 7 and the aqueous medium 9 is not particularly limited as long as the above formulas (1) to (3) are satisfied, but is preferable from the viewpoint of efficiently producing good-quality core-shell particles. Is more than 0 mN / m and 180 mN / m or less, more preferably about 5 to 160 mN / m. The interfacial tension γ3 between the second oil medium 8 and the aqueous medium 9 is not particularly limited as long as the above formulas (1) to (3) are satisfied, but preferably 0 mN from the viewpoint of efficiently producing good-quality core-shell particles. / M to 10 mN / m or less, more preferably 0 mN / m to 5 mN / m or less.

In the present invention, from the viewpoint of efficiently producing good-quality core-shell particles, the interfacial tension γ1 between the first oil medium 7 and the second oil medium 8 and the interface between the second oil medium 8 and the aqueous medium 9 are used. It is preferable that the tension γ3 further satisfies the relationship of the following formula (4). Thereby, in the formation process of the core-shell particles, the second oil medium 8 becomes spherical so as to cover the first oil medium 7, so that the surface free energy when the two-phase liquid medium forms a spherical shape is further increased. Decrease and produce stable particles.
Formula (4): γ3> γ1

  In the production method of the present invention, the method for supplying the first oily medium 7 and the second oily medium 8 to the first microchannel 1 and the second microchannel 2, respectively, is not particularly limited, and is a known microchannel method. The method used can be employed. Examples of the method used in the known microchannel method include a method using a liquid supply device capable of adjusting the flow rate, such as a syringe and a syringe pump. Commercially available products can be used as the syringe and syringe pump. Examples of commercially available syringes include Terumo syringes manufactured by Terumo Corporation and gas tight syringes manufactured by Hamilton. Examples of commercially available syringe pumps include Legato 100 manufactured by Muromachi Kikai Co., Ltd., and KDS-100 manufactured by KD SCIENTIFIC. The syringe is connected to the microchip using a commercially available tube. As the tube, a PTFE tube or the like can be suitably used.

  The flow rate of the first oily medium 7 in the first microchannel 1 is not particularly limited, but is preferably about 0.1 to 50 ml / hr, more preferably 0 from the viewpoint of efficiently producing good-quality core-shell particles. About 5 to 30 ml / hr, more preferably about 2.5 to 5 ml / hr. The flow rate of the second oil medium 8 in the second microchannel 2 is not particularly limited, but from the same viewpoint, it is preferably about 0.1 to 50 ml / hr, more preferably about 0.5 to 30 ml / hr. More preferably, about 2.5-5 ml / hr is mentioned.

  In the production method of the present invention, from the viewpoint of efficiently producing good-quality core-shell particles, the first oil medium 7 and the second oil medium 8 flowing through the third microchannel 3 are provided as shown in FIG. At a portion discharged into the aqueous medium 9, a second confluence point Q where the third microchannel 3, the fourth microchannel 4 through which the aqueous medium 9 flows, and the fifth microchannel through which the aqueous medium 9 flows merges. It is preferable to provide.

  In the manufacturing method of the present invention, at the second confluence point Q, the flowing direction of the aqueous medium 9 flowing through the fourth microchannel 4 and the flowing direction of the aqueous medium 9 flowing through the fifth microchannel 5 are angles of 180 ° or less. It is preferable that the aqueous medium 9 flowing through the fourth microchannel 4 and the aqueous medium 9 flowing through the fifth microchannel 5 are joined together.

  For example, as shown in FIG. 1, the aqueous medium 9 flowing through the fourth microchannel 4 and the aqueous medium 9 flowing through the fifth microchannel 5 are flowing in opposite directions, and merge at the second confluence point Q. It may be. That is, at the second confluence point Q, the flow direction of the aqueous medium 9 flowing through the fourth microchannel 4 and the flow direction of the aqueous medium 9 flowing through the fifth microchannel 5 form an angle of 180 °. The aqueous medium 9 flowing through the 4 microchannels 4 and the aqueous medium 9 flowing through the fifth microchannels 5 may merge.

  For example, as shown in FIG. 7 described later, at the second junction point Q, the flowing direction of the aqueous medium 9 flowing through the fourth microchannel 4 and the flowing direction of the aqueous medium 9 flowing through the fifth microchannel 5 are determined. The aqueous medium 9 flowing through the fourth microchannel 4 and the aqueous medium 9 flowing through the fifth microchannel 5 may be joined so as to form an angle of less than 180 °.

  As shown in FIG. 1, the first oil medium 7 and the second oil medium 8 are discharged into the aqueous medium 9 at the second confluence point Q (step 2). In step 2, the first oil medium 7 and the second oil medium 8 that have joined the aqueous medium 9 at the second confluence point Q pass through the sixth microchannel 6 that continues downstream from the second confluence point Q, while passing through the core shell. It is preferable to form particles.

  As a method for supplying the aqueous medium 9 to the fourth and fifth microchannels 4 and 5, as in the first oily medium 7 and the second oily medium 8, a method used in the above-described known microchannel method is adopted. Can do.

  The flow rate of the aqueous medium 9 flowing through the fourth and fifth microchannels 4 and 5 is not particularly limited, but is preferably about 30 to 200 ml / hr, respectively, from the viewpoint of efficiently producing good-quality core-shell particles. More preferably, about 50-150 ml / hr is mentioned. The flow rate of the aqueous medium 9 flowing through the fourth microchannel 4 and the flow rate of the aqueous medium 9 flowing through the fifth microchannel 5 may be different from the viewpoint of efficiently producing good-quality core-shell particles. Are preferably the same (for example, the flow rate difference is about -2 to 2 ml / hr).

  In the present invention, the first microchannel 1, the second microchannel 2, the third microchannel 3 that is the combined flow path of these microchannels, the fourth microchannel 4, the fifth microchannel 5, and the sixth microchannel 6 are These are minute channels formed on a substrate or the like.

  In the present invention, the diameter of the first microchannel 1 (perpendicular to the length direction) is not particularly limited, but is preferably about 100 to 900 μm from the viewpoint of efficiently producing good-quality core-shell particles. Preferably about 300-700 micrometers is mentioned. In addition, the diameter (the direction perpendicular to the length direction) of the second microchannel 2 is not particularly limited, but from the same viewpoint, it is preferably about 100 to 900 μm, more preferably about 300 to 700 μm. Although it does not restrict | limit especially as a diameter (perpendicular to a length direction) of the 3rd microchannel 3, Preferably it is about 100-900 micrometers from a similar viewpoint, More preferably, about 300-700 micrometers is mentioned.

  Further, the diameter (the direction perpendicular to the length direction) of the fourth and fifth microchannels 4 and 5 for supplying the aqueous medium 9 is not particularly limited, but from the viewpoint of efficiently producing good-quality core-shell particles. Preferably, about 300-2000 micrometers, More preferably, about 500-1500 micrometers is mentioned.

  Further, the diameter (the direction perpendicular to the length direction) of the sixth microchannel 6 for forming the core-shell particles is not particularly limited, but is preferably 300 to 2000 μm from the viewpoint of efficiently producing good-quality core-shell particles. About, More preferably, about 500-1500 micrometers is mentioned.

  The particle diameter of the core-shell particles produced by the production method of the present invention can be adjusted by the diameter of the microchannel (the direction perpendicular to the length direction). For example, the diameter of the first, second, and third microchannels is 300 μm. The core-shell particles having a particle diameter of about 150 to 250 μm are obtained, and when the diameter is about 500 μm, the core-shell particles having a particle diameter of about 350 to 450 μm are obtained, and the diameter is about 700 μm. In some cases, core-shell particles having a particle size of about 500 to 650 μm are obtained.

  Further, the length (flow direction) of the first microchannel 1 is not particularly limited, but is preferably about 0.1 to 8 mm, more preferably about 1 to 8 mm, from the viewpoint of efficiently producing good-quality core-shell particles. About 6 mm is mentioned. Although it does not restrict | limit especially as the length (flow direction) of the 2nd microchannel 2, From the same viewpoint, Preferably it is about 0.1-8 mm, More preferably, about 1-6 mm is mentioned. Although it does not restrict | limit especially as the length (flow direction) of the 3rd micro channel 3, From the same viewpoint, Preferably it is about 0.1-8 mm, More preferably, about 1-6 mm is mentioned.

  The length (flow direction) of the fourth and fifth microchannels 4 and 5 for supplying the aqueous medium 9 is not particularly limited, but is preferably 0.1 from the viewpoint of efficiently producing high-quality core-shell particles. About 8 mm, More preferably, about 1-6 mm is mentioned.

  The length (flow direction) of the sixth microchannel 6 for forming the core-shell particles is not particularly limited, but is preferably about 1 to 15 mm, more preferably 5 from the viewpoint of efficiently producing high-quality core-shell particles. About 10 mm.

  In the present invention, when producing solid core-shell particles, Step 3 of curing the core-shell particles 10 formed in the aqueous medium 9 in Step 2 described above can be performed. For example, when the first oil medium 7 and the second oil medium 8 contain a thermosetting or photocurable component, the core-shell particles 10 can be cured by heating or light irradiation.

  In step 3, step 3-1 for curing the core-shell particles 10 in the aqueous medium 9 may be provided.

  In step 3-1, the heating temperature in the case of heat-curing in the aqueous medium 9 is not particularly limited as long as it is a temperature not higher than the boiling point of the aqueous medium 9 and can cure the core part and the shell part, but preferably Is about 60 to 98 ° C. The heating time in the case of heat-curing in the aqueous medium 9 is not particularly limited, but preferably about 0.1 to 5 hours.

  In step 3-1, the core-shell particles 10 precured in the aqueous medium 9 at the heating temperature as described above may be further heated at a high temperature to be cured (main curing). Although it does not restrict | limit especially as heating temperature in this hardening, Preferably about 100-200 degreeC is mentioned. Although it does not restrict | limit especially as heating time in this hardening, Preferably about 0.5 to 8 hours are mentioned. The main curing in the aqueous medium 9 can be performed using, for example, a pressure vessel.

  Moreover, in the process 3, after separating the core-shell particle 10 and the aqueous medium 9, the process 3-2 which hardens the core-shell particle 10 may be provided.

  In step 3-2, the heating temperature when the core-shell particles 10 separated from the aqueous medium 9 are heated and cured can evaporate the oil solvent in the core part and the shell part, and the core part and the shell part are cured. Although it will not restrict | limit especially if it is temperature which can be performed, Preferably about 100-200 degreeC is mentioned.

  Further, in Step 3, after the core-shell particles 10 are cured in the aqueous medium 9, the core-shell particles 10 are separated from the core-shell particles 10 cured in the step 3-1 (pre-cured) and the aqueous medium 9, and then the core-shell particles. Step 3-2 for further curing (main curing) 10 may be provided.

  When including Step 3-1 and Step 3-2, in Step 3-1, heating is performed at a temperature higher than the curing temperature of the core portion and lower than the boiling point of the oily solvent contained in the second oily medium 8, and subsequently In step 3-2, it is preferable to heat the core-shell particles 10 at a temperature higher than the curing temperature of the shell portion and higher than the boiling point of the oily solvent contained in the first oily medium 7 and the second oily medium 8. Thereby, first, the core part hardens | cures with the shell part being liquid state by the preliminary hardening of process 3-1, When the core part hardens | cures, the oil-based solvent contained in a core part can be transferred to a shell part. Next, in the main curing in Step 3-2, along with the curing of the shell portion, the oil-based solvent contained in the shell portion is evaporated, and solid high-quality core-shell particles can be produced.

  When performing heat curing in two stages of curing in step 3-1 (preliminary curing) and curing in step 3-2 (main curing), the heating temperature in step 3-1 is preferably about 60 to 98 ° C. The heating temperature in step 3-2 is preferably about 100 to 200 ° C. The heating time in preliminary curing and main curing is not particularly limited, and examples thereof include the above-described heating times.

  The method for separating the core-shell particles 10 from the aqueous medium 9 is not particularly limited, and examples thereof include known methods such as filtration and drying.

  The manufacturing method of the present invention includes, for example, a first microchannel 1, a second microchannel 2, a third microchannel 3, a fourth microchannel 4, a fifth microchannel 5, and a sixth microchannel as shown in FIG. 6, it is also possible to manufacture using a microchip having a plurality of first junction points P and a plurality of second junction points Q.

  For example, in the microchip shown in FIG. 7, the first oil medium 7 supplied from the first oil medium supply port 1a flows in the first microchannel 1 in two directions. Similarly, the second oil medium 8 supplied from the second oil medium supply port 2 a also flows in the second microchannel 2 in two directions. Thereafter, the first oil medium 7 flowing through the first microchannel 1 and the second oil medium 8 flowing through the second microchannel 2 are respectively connected to the first junction P of the first microchannel 1 and the second microchannel 2. Join at. (Step 1). Furthermore, following the step 1, the first oil medium 7 and the second oil medium 8 flowing through the third microchannel 3 continuing downstream from the first confluence P are discharged into the aqueous medium 9, and the first oil medium 7 Can form core-shell particles 10 in which the core portion and the second oil-based medium 8 constitute the shell portion (step 2).

  In the microchip shown in FIG. 7, the aqueous medium 9 supplied from the aqueous medium supply port 4a also flows in the fourth microchannel 4 in two directions. Similarly, the aqueous medium 9 supplied from the supply port 5a of the aqueous medium 9 also flows in the fifth microchannel 5 in two directions. As described above, at the second confluence point Q, the flowing direction of the aqueous medium 9 flowing through the fourth microchannel 4 and the flowing direction of the aqueous medium 9 flowing through the fifth microchannel 5 form an angle of less than 180 °. As shown, the aqueous medium 9 flowing through the fourth microchannel 4 and the aqueous medium 9 flowing through the fifth microchannel 5 merge.

  In the microchip shown in FIG. 7, the number of first joining points P and second joining points Q is eight, and the number of third microchannels 3 and sixth microchannels 6 is also eight. is there.

  By the production method of the present invention described above, the core-shell particles can be suitably produced. For example, as shown in FIG. 3, the core-shell particle 10 produced by the production method of the present invention includes a core part 11 and a shell part 12 that covers the surface of the core part 11.

  Although it does not restrict | limit especially as a diameter of the core part 11, As what is manufactured suitably by the manufacturing method of this invention, Preferably it is 900 micrometers or less, More preferably, about 100-700 micrometers is mentioned.

  Although it does not restrict | limit especially as thickness of the shell part 12, As what is manufactured suitably by the manufacturing method of this invention, Preferably it is 100 micrometers or less, More preferably, about 1-80 micrometers is mentioned.

  Although it does not restrict | limit especially as a particle diameter of the core-shell particle 10 of this invention, As what is manufactured suitably by the manufacturing method of this invention, Preferably it is 1000 micrometers or less, More preferably, about 100-800 micrometers is mentioned.

  The core-shell particle 10 can be suitably used, for example, as an insulating spacer for electronic equipment.

  Furthermore, the electroconductive particle 20 as shown in FIG. 4 is obtained by covering the surface of the core shell particle 10 with the electroconductive metal film 13.

  The conductive particles 20 include a core part 11, a shell part 12 that covers the surface of the core part 11, and a conductive metal film 13 that covers the surface of the shell part. In the conductive particle 20, the core part 11 and the shell part 12 are the same as the core-shell particle 10 described above. The conductive particles 20 of the present invention are obtained by forming the conductive metal film 13 on the surface of the core-shell particles 10 manufactured by the manufacturing method of the present invention.

  Although it does not restrict | limit especially as a metal which comprises the electroconductive metal film 13, From a viewpoint which exhibits the outstanding electroconductivity, for example, aluminum, copper, nickel, gold, titanium, chromium, silver, palladium, platinum, and these metals And an alloy containing at least one of the above.

  The thickness of the conductive metal film 13 is not particularly limited, but is preferably 200 μm or less, more preferably about 1 to 150 μm from the viewpoint of exhibiting excellent conductivity as fine particles.

  Although it does not restrict | limit especially as a particle diameter of the electroconductive particle 20 of this invention, From a viewpoint of exhibiting the outstanding electroconductivity as a fine particle, Preferably it is 1200 micrometers or less, More preferably, about 100-1000 micrometers is mentioned.

  The electroconductive particle 20 of this invention can be used conveniently in an electronic component etc. More specifically, it can be suitably used as a connector or the like disposed between conductive members (for example, between electrodes) on a substrate of an electronic component.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

(Measurement of interfacial tension)
In Examples and Comparative Examples, the interfacial tension γ1 between the first oily medium and the second oily medium, the interfacial tension γ2 between the first oily medium and the aqueous medium, and the interfacial tension γ3 between the second oily medium and the aqueous medium. Were measured using an automatic contact angle meter DMs-401 manufactured by Kyowa Interface Science Co., Ltd. From these values, values of γ1- (γ2 + γ3), γ2- (γ1 + γ3) and γ3- (γ1 + γ2) were calculated. These results are shown in Table 1.

(Confirmation of particle generation)
In the examples and comparative examples, the two-phase flow of the first oil medium and the second oil medium flowing in the third microchannel is in the aqueous medium at the second confluence point Q using the high speed camera FASTCAM MAX 120K manufactured by Photoron. The state of particle generation was confirmed by observing the state of being discharged into the nozzle. As a result, “○” indicates that particles with a uniform particle size are generated, “Δ” indicates that microparticles and lint-like precipitates are generated together with the particles, and a massive precipitate is generated without generating particles. The case was evaluated as “×”. The results are shown in Table 1.

(Confirmation of particle core-shell structure)
In the examples and comparative examples, the cross section of the obtained particles was observed with an electron microscope to confirm the presence or absence of the core-shell structure. The case where the core-shell structure was confirmed was evaluated as “◯”, and the case where the core-shell structure was not confirmed was evaluated as “x”. The results are shown in Table 1.
In Comparative Examples 1 and 2, particles were not obtained and the presence or absence of the core-shell structure could not be confirmed.

Example 1
As the first oily medium, one obtained by adding 33.4 parts by mass of toluene to 66.6 parts by mass of thermosetting liquid silicone rubber was used. Moreover, the solvent of a polyimide solution (made by Arakawa Chemical Industries, PIAD300) was distilled off with a vacuum dryer as the second oily medium, and 70.0 parts by mass of toluene was added to 30.0 parts by mass of the obtained polyimide solid. The mixture was stirred for 24 hours at room temperature to dissolve, and 2.2 parts by mass of a curing agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., TETRAD-X) was added and stirred for 5 minutes. As an aqueous medium, an aqueous solution in which 98.0 parts by mass of pure water was added to 2.0 parts by mass of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd., Gohsenol GL-03) was used.

  Using a microchip having microchannels as shown in FIG. 2, a first oil medium is supplied from the first microchannel 1 at a flow rate of 0.2 ml / hr using a syringe pump (KDS-200 manufactured by KD scientific). did. Similarly, the second oily medium was supplied from the second microchannel 2 at a flow rate of 0.2 ml / hr using a syringe pump (KDS-200 manufactured by KD scientific). Similarly, an aqueous medium was supplied from the fourth microchannel 4 and the fifth microchannel 5 at a flow rate of 100 ml / hr using a syringe pump (KDS-200 manufactured by KD scientific). The first oil medium 7 flowing through the first microchannel 1 and the second oil medium 8 flowing through the second microchannel 2 are merged at the first junction P of the first microchannel and the second microchannel; The first oil medium 7 and the second oil medium 8 flowing through the third microchannel 3 continuing downstream from the first junction P were discharged into the aqueous medium 9. As shown in FIG. 2, the first oil medium 7 and the second oil medium 8 are discharged into the aqueous medium 9 at the second confluence point Q. The first oil medium 7 and the second oil medium 8 that merged with the aqueous medium 9 at the second merge point Q passed through the sixth microchannel 6 and were discharged out of the microchip while forming core-shell particles. The discharged core-shell particles 10 and the aqueous medium 9 were collected in a 100 ml glass beaker containing 50.0 g of the aqueous medium 9. In FIG. 5, the photograph of the 2nd confluence | merging point Q is shown. Shooting was performed using a high-speed camera (FASTCAM MAX 120K manufactured by Photron) (shooting conditions: 500 fps, skip: 0), and the same applies to FIG. 6 described later.

  Next, the recovered core-shell particles 10 and the aqueous medium 9 were precured by heating at 95 ° C. for 1 hour after distilling off toluene under a reduced pressure of atmospheric pressure to −90 kPa. Next, after removing the aqueous medium by decantation, the core-shell particles were washed with pure water three times. Next, the washed core-shell particles were cured at 130 ° C. for 1 hour and then at 180 ° C. for 3 hours to obtain cured core-shell particles.

(Examples 2 to 6)
The first oily medium, the second oily medium, and the aqueous medium each having the composition shown in Table 1 were used, the first oily medium flowing through the first microchannel, and the second oily flowing through the second microchannel. Cured core-shell particles were obtained in the same manner as in Example 1 except that the flow rates of the medium and the aqueous medium flowing through the fourth and fifth microchannels were set to the values shown in Table 1, respectively.

(Comparative Examples 1 and 2)
The first oily medium, the second oily medium, and the aqueous medium each having the composition shown in Table 1 were used, the first oily medium flowing through the first microchannel, and the second oily flowing through the second microchannel. The production of particles was attempted in the same manner as in Examples 1 to 6 except that the flow rates of the aqueous medium flowing through the medium and the fourth and fifth microchannels were set to the values shown in Table 1, respectively. In Comparative Examples 1 and 2, particles were not formed at the second confluence point Q, and massive (string-like) precipitates were generated. That is, core-shell particles could not be produced. In FIG. 6, the photograph of the 2nd confluence | merging point Q in the comparative example 1 is shown. Comparative Example 2 was in the same state as Comparative Example 1.

  As is clear from the results shown in Table 1, using the microchip in which the microchannels as shown in FIG. 2 are formed, the values of the above-mentioned interfacial tensions γ1, γ2, and γ3 are the above formulas (1) to (1) to In Examples 1 to 6 using the first oily medium, the second oily medium, and the aqueous medium that satisfy the relationship (3), high-quality core-shell particles could be efficiently produced. On the other hand, in the same manner as in Examples 1 to 6, a microchip having a microchannel as shown in FIG. 2 was used, and the values of γ1, γ2, and γ3 were determined by the above formulas (1) and (3). In Comparative Examples 1 and 2 that satisfy the relationship (2) but do not satisfy the relationship (2), no particles were formed.

DESCRIPTION OF SYMBOLS 1 1st microchannel 1a 1st oily medium supply port 2 2nd microchannel 2a 2nd oily medium supply port 3 3rd microchannel 4 4th microchannel 4a Aqueous medium supply port 5 5th microchannel 5a Aqueous medium Supply port 6 Sixth microchannel 7 First oil medium 8 Second oil medium 9 Aqueous medium 10 Core-shell particle P First confluence Q Second confluence

Claims (11)

A step 1 of joining a first oily medium flowing through the first microchannel and a second oily medium flowing through the second microchannel at a first confluence of the first microchannel and the second microchannel;
Subsequent to the step 1, the first oil medium and the second oil medium flowing through the third microchannel continuing downstream from the first merge point are discharged into an aqueous medium, and the first oil medium is a core portion. Step 2 for forming core-shell particles, wherein the second oily medium constitutes a shell part;
With
The interfacial tension between the first oily medium and the second oily medium is γ1, the interfacial tension between the first oily medium and the aqueous medium is γ2, and the interface between the second oily medium and the aqueous medium is Using the first oily medium, the second oily medium, and the aqueous medium in which the values of γ1, γ2, and γ3 satisfy the following formulas (1) to (3) when the tension is γ3, Production method.
Formula (1): 0> γ1- (γ2 + γ3)
Formula (2): 0 <γ2- (γ1 + γ3) <151
Formula (3): 0> γ3- (γ1 + γ2)   The method for producing core-shell particles according to claim 1, wherein the first oily medium and the second oily medium each contain a polymer or a monomer.   The method for producing core-shell particles according to claim 1 or 2, wherein the first oil-based medium contains silicone and the second oil-based medium contains polyimide.   The method for producing core-shell particles according to claim 2 or 3, wherein at least one of the first oily medium and the second oily medium further contains a curing agent.   The manufacturing method of the core-shell particle in any one of Claims 1-4 in which the said aqueous medium contains polyvinyl alcohol.   The third microchannel, the fourth microchannel in which the aqueous medium flows, and the fifth microchannel in which the aqueous medium flows in a portion where the first oily medium and the second oily medium are discharged into the aqueous medium. The manufacturing method of the core-shell particle in any one of Claims 1-5 provided with the 2nd confluence | merging point with which a channel merges.   In the second confluence, the flow direction of the aqueous medium flowing through the fourth microchannel and the flow direction of the aqueous medium flowing through the fifth microchannel form an angle of 180 ° or less. The method for producing core-shell particles according to claim 6, wherein the aqueous medium flowing through 4 microchannels and the aqueous medium flowing through the fifth microchannel are merged.   The manufacturing method of the core-shell particle of Claim 7 provided with the process 3 which hardens a core-shell particle after the said process 2. FIG.   The method for producing core-shell particles according to claim 8, comprising the step 3-1 of curing the core-shell particles in the aqueous medium in the step 3.   The method for producing core-shell particles according to claim 8, further comprising a step 3-2 of curing the core-shell particles after separating the core-shell particles and the aqueous medium in the step 3. Step 3-1 in which the core-shell particles are cured in the aqueous medium in the step 3, and the core-shell particles cured in the step 3-1 are separated from the aqueous medium, and then the core-shell particles are cured 3- The method for producing core-shell particles according to claim 8, comprising 2.