JP2019005691A - Method for producing emulsion - Google Patents

Abstract

To provide a method for producing emulsion in which the control of particle size of dispersed particles can easily be done.SOLUTION: In the method for producing emulsion, the mixed liquid L of aqueous phase and oil phase is caused to circulate through the line 12 interposed with the pump 13 and the static type mixer 14 once or a plurality of times. The circulation of the mixed liquid L to the line 12 is controlled such that, at the initial circulation, the average particle size of dispersed particles in the mixed liquid L after leaving the pump 13 is 40.0% or more with respect to the average particle size of dispersed particles in the mixed liquid L before entering the pump 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing an emulsion and a method for producing microcapsule particles using the same.

  Emulsions are used in many fields such as recording materials, agricultural chemicals, medicines, fragrances, liquid crystals, adhesives and the like. And the method of manufacturing this emulsion using a static mixer is known. For example, Patent Documents 1 and 2 disclose a method for producing a water-in-oil emulsion in which a mixed liquid of an aqueous phase and an oil phase is circulated and circulated through a circulation line provided with a static mixer. . Patent Document 3 discloses a method for producing an oil-in-water emulsion in which a mixed liquid of an aqueous phase and an oil phase is passed through a static mixer in one pass.

JP 2011-26381 A JP 2008-63409 A JP 2003-305360 A

  The subject of this invention is providing the manufacturing method of the emulsion which can perform the particle size control of a dispersed particle easily.

  The present invention is a method for producing an emulsion in which a mixed liquid of an aqueous phase and an oil phase is circulated once or a plurality of times through a line in which a pump and a static mixer are interposed, and the mixed liquid is supplied to the line. In the initial distribution, the average particle diameter of the dispersed particles in the mixed liquid after leaving the pump is 40.0% with respect to the average particle diameter of the dispersed particles in the mixed liquid before entering the pump. It controls to become above.

  This invention is a manufacturing method of the microcapsule particle which polymerizes the said vinyl monomer, after obtaining the emulsion in which the said dispersion particle contains a vinyl monomer by the manufacturing method of the emulsion of this invention.

  According to the present invention, the flow of the mixed liquid to the line is the average of the dispersed particles of the mixed liquid after exiting the pump with respect to the average particle diameter of the dispersed particles in the mixed liquid before entering the pump during the initial distribution. Since the particle size is controlled to be 40.0% or more, the influence of the pump on the particle size of the dispersed particles is small. As a result, the particle size of the dispersed particles can be easily controlled by a static mixer. .

It is a figure which shows the structure of a 1st emulsion manufacturing apparatus. It is a perspective view which shows an example of a static mixer. It is sectional drawing of an example of a static mixer. It is a top view of the 1st element which comprises the unit of a static mixer. It is a top view of the 2nd element which comprises the unit of a static mixer. It is a perspective view which shows a flow-path hole. It is explanatory drawing which shows the flow of the liquid mixture in a static mixer. It is a figure which shows the structure of a 2nd emulsion manufacturing apparatus. It is a figure which shows the structure of the modification which provided the several static mixer in series. It is a figure which shows the structure of the modification which provided the several static mixer in parallel.

  Hereinafter, embodiments will be described in detail.

(Emulsion production method)
Drawing 1 shows the 1st emulsion manufacture device 10 which can be used for the manufacturing method of the emulsion concerning an embodiment.

  The first emulsion manufacturing apparatus 10 includes a mixed liquid storage tank 11 and an external circulation line 12 attached to the mixed liquid storage tank 11.

  The mixed liquid storage tank 11 is constituted by a storage tank provided with a stirrer 11a. Examples of the stirring blade provided in the stirrer 11a include an anchor blade, a propeller blade, a paddle blade, and a turbine blade. The stirrer 11a preferably has one or more of these stirring blades. The mixed liquid storage tank 11 is preferably provided with a temperature control function. In the first emulsion production apparatus 10, a mixed liquid L of an aqueous phase and an oil phase is charged into the mixed liquid storage tank 11, and the stirrer 11a agitates the mixed liquid L to change one of the aqueous phase and the oil phase to the other. Can be predispersed.

  The external circulation line 12 includes a pipe that is provided so as to extend from the bottom of the mixed liquid storage tank 11 and is coupled to the upper part of the mixed liquid storage tank 11.

  A pump 13 is interposed in the external circulation line 12. Examples of the pump 13 include a low shear pump such as a screw pump, an eccentric disk pump, a sine pump, and a peristaltic pump. Commercially available low shear pumps include, for example, “Hayshin Mono Pump”, a screw pump manufactured by Hyoji Equipment Co., Ltd., a snake pump manufactured by Yamada Tekko Co., Ltd., an eccentric disk pump manufactured by Movex, and a sign pump manufactured by Watson-Marlow. . In the first emulsion manufacturing apparatus 10, the pump 13 causes the liquid mixture L in the liquid mixture storage tank 11 to flow out from the bottom of the liquid mixture storage tank 11 to the external circulation line 12, and then the liquid mixture from the external circulation line 12. The liquid is fed so as to flow into the upper part of the storage tank 11, whereby the mixed liquid L in the mixed liquid storage tank 11 is circulated through the external circulation line 12 and circulated.

  A static mixer 14 is interposed between the pump 13 and the upper coupling portion of the mixed liquid storage tank 11 in the external circulation line 12, that is, downstream of the pump 13. The static mixer 14 is a mixer that does not have liquid feed driving means such as an agitator or a rotor. Examples of the static mixer 14 include a mixer having an orifice structure or a honeycomb structure. Examples of the commercially available static mixer 14 include “Dispersion-kun” and “Mixing-kun” manufactured by Fujikin, and “Ramond Nanomixer” manufactured by Nanocus. In the first emulsion production apparatus 10, the static mixer 14 shears the liquid mixture L flowing through the external circulation line 12 and passing through the static mixer 14, thereby reducing the diameter of the dispersed particles. Let

  FIGS. 2A and 2B show the schematic structure of “Dispersion-kun” manufactured by Fujikin as an example of a commercially available static mixer 14.

  The static mixer 14 has a structure in which disk-shaped first and second elements 141 and 142 are stacked to form a unit, and a single unit or a plurality of units are provided (5 units in FIGS. 2A and 2B). . The number of units is, for example, 1 or more and 10 or less. In the static mixer 14 provided with a plurality of units, the first and second elements 141 and 142 are alternately stacked.

  As shown in FIG. 3A, the first element 141 is provided with four through holes formed in the center portion so as to penetrate in the thickness direction so as to be arranged in a 2 × 2 square. . As shown in FIG. 3B, the second element 142 has five flow holes formed in the central portion so as to penetrate in the thickness direction, one at the center and two surrounding four holes. It is provided to be arranged in a square of × 2.

  As shown in FIG. 4, each flow path hole 143 of the first and second elements 141 and 142 includes a contracted portion 143 a that is the narrowest part of the flow path formed by a cylindrical hole having a small inner diameter at the center part, It has an inflow portion 143b and an outflow portion 143c provided on one side and the other side of the contracted portion 143a. Each of the inflow part 143b and the outflow part 143c is comprised by the truncated cone hole formed so that an internal diameter might become large gradually toward an opening continuously from the contraction part 143a. The inner diameter d1 of the contracted portion 143a is, for example, not less than 0.2 mm and not more than 10 mm. The length l of the contracted portion 143a is, for example, not less than 1.0 mm and not more than 4.0 mm. The opening diameter d2 of the inflow part 143b and the outflow part 143c is 1 mm or more and 50 mm or less, for example.

  The first and second elements 141 and 142 communicate with the respective flow passage holes 143 of the first element 141 and the three flow passage holes 143 of the second element 142, and each of the four flow passage holes 143 arranged squarely. Is positioned and laminated so that the diagonal line of the square with apex is shifted by 45 °.

  In the static mixer 14, as shown in FIG. 5, the mixed liquid L is divided into the inflow portions 143 b of the four flow path holes 143 in the first first element 141 and flows into the flow path holes 143. After flowing through the contracted flow part 143a, it flows out to the outflow part 143c. The mixed liquid L flowing out from the outflow portion 143c of each flow path hole 143 of the first element 141 is divided into the inflow portions 143b of the three flow path holes 143 in the next second element 142 and flows into the first element 141. The element 141 merges with the liquid mixture L from the other channel hole 143, flows through the contracted portion 143a of each channel hole 143, and then flows out to the outflow portion 143c. The mixed liquid L flowing out from the outflow portion 143c of each flow path hole 143 of the second element 142 is divided into the inflow portions 143b of the two or four flow path holes 143 and flows into the first element 141 of the next unit. At the same time, it merges with the mixed liquid L from the other channel hole 143 of the second element 142, flows through the contracted portion 143a of each channel hole 143, and then flows out to the outflow portion 143c. The mixed liquid L is sheared by repeating such division, merging, and contraction.

  In the emulsion manufacturing method using the first emulsion manufacturing apparatus 10, first, the mixed liquid L of the aqueous phase and the oil phase is charged into the mixed liquid storage tank 11. At this time, the mixed liquid storage tank 11 may be charged with the oil phase after charging the water phase, or may be charged with the water phase after charging the oil phase. You may throw in the liquid mixture L of an aqueous phase and an oil phase.

  The content of each of the water phase and the oil phase in the mixed liquid L depends on whether the oil-in-water (O / W) emulsion or the water-in-oil (W / O) emulsion is produced. Appropriately set in consideration of dispersion stability.

  It is preferable to contain a dispersion stabilizer in the aqueous phase or the oil phase or both. Examples of the dispersion stabilizer include an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, a water-soluble polymer, and an oil-soluble polymer. The content of the dispersion stabilizer in the mixed solution L is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and still more preferably, from the viewpoint of improving the productivity while forming an emulsion of uniform dispersed particles. Is 1.0% by mass or more, and from the same viewpoint, it is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, and still more preferably 3.0% by mass or less. The content of the dispersion stabilizer in the mixed liquid L is preferably 0.1% by mass or more and 5.0% by mass or less, more preferably 0.5% by mass or more and 4.0% by mass or less, and further preferably 1.0% by mass. % To 3.0% by mass.

  The average particle diameter D1 of the dispersed particles (hereinafter referred to as “initial average particle diameter D1”) before the initial distribution of the mixed liquid L charged in the mixed liquid storage tank 11 to the external circulation line 12 is the dispersed particles by the static mixer 14. From the viewpoint of improving the accuracy of particle size control, it is preferably 40 μm or more, more preferably 50 μm or more, and even more preferably 60 μm or more. Also, from the viewpoint of increasing the productivity of the emulsion by shortening the dispersion time, preferably 100 μm. Hereinafter, it is more preferably 90 μm or less, and still more preferably 80 μm or less. The initial average particle diameter D1 is preferably 40 μm or more and 100 μm or less, more preferably 50 μm or more and 90 μm or less, and still more preferably 60 μm or more and 80 μm or less. Here, all the average particle diameters in this application are volume median diameters. The volume median diameter is a particle diameter at which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle diameter.

  Before the initial distribution of the mixed liquid L to the external circulation line 12, from the viewpoint of obtaining the initial average particle diameter D1 of the dispersed particles as described above, the mixed liquid L is stirred to remove one of the aqueous phase and the oil phase. It is preferable to preliminarily disperse the other. The stirring time is, for example, 30 seconds or longer. The peripheral speed of the stirring blade is, for example, 0.7 m / second or more. In addition, after preparing the liquid mixture L to the liquid mixture storage tank 11, you may perform this preliminary dispersion by operating the stirrer 11a. Moreover, preparation of the liquid mixture L and this preliminary dispersion are carried out with the liquid mixture storage tank 11. After performing in a separate storage tank, the mixed liquid L after preliminary dispersion may be charged into the mixed liquid storage tank 11.

  The temperature of the mixed liquid L at the time of preliminary dispersion is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, further preferably 15 ° C. or higher, from the viewpoints of the operability of the preliminary dispersion and the solubility of the constituent components. From the same viewpoint, it is preferably 100 ° C. or lower, more preferably 40 ° C. or lower, still more preferably 30 ° C. or lower. The temperature of the liquid mixture L at the time of preliminary dispersion is preferably 5 ° C. or higher and 100 ° C. or lower, more preferably 10 ° C. or higher and 40 ° C. or lower, and further preferably 15 ° C. or higher and 30 ° C. or lower.

  Then, the pump 13 is operated. Thereby, the mixed liquid L in the mixed liquid storage tank 11 is fed by the pump 13, is circulated through the external circulation line 12, and is repeatedly passed once or a plurality of times through the static mixer 14, thereby dispersing the dispersed particles with a small diameter. To obtain an emulsion in the mixed solution storage tank 11.

  By the way, the inventors of the present invention have difficulty in controlling the particle size of the dispersed particles during the production of the emulsion using the static mixer 14, and the influence of the pump 13 that feeds the liquid mixture L of the aqueous phase and the oil phase. I found it big. Therefore, in the method for producing an emulsion according to the embodiment, the average particle diameter D2 of dispersed particles in the mixed liquid L before entering the pump 13 during the initial distribution (hereinafter referred to as “ (Referred to as “average particle diameter D2 before pump 13”) (hereinafter referred to as “average particle diameter D3 after pump 13”) (D3). / D2) × 100 is controlled to be 40.0% or more.

  According to the emulsion manufacturing method of this embodiment, the average particle diameter D3 after the pump 13 is compared with the average particle diameter D2 before the pump 13 during the initial distribution of the mixture L to the external circulation line 12. Therefore, the influence of the pump 13 on the particle size of the dispersed particles is small, and as a result, the particle size control of the dispersed particles by the static mixer 14 can be easily performed. . Such control can be performed by using the pump 13 having low shear applied to the mixed liquid L or setting the flow rate of the mixed liquid L by the pump 13, but a low shear pump is used as the pump 13 for feeding the mixed liquid L. It is preferable to use it.

  Here, in the emulsion production method using the first emulsion production apparatus 10, the initial circulation of the mixed liquid L to the external circulation line 12 means the average circulation from the start of the distribution of the mixed liquid L to the external circulation line 12. It is any time during which the number of times reaches one. The average number of circulations of the mixed liquid L to the external circulation line 12 is obtained by dividing the total flow rate flowing to the external circulation line 12 by the total volume of the mixed liquid L. The average number of circulation times of the mixed liquid L to the external circulation line 12 also corresponds to the average number of passage times of the mixed liquid L to the stationary mixer 14.

  At the first distribution of the mixed liquid L to the external circulation line 12, the average particle diameter D3 after the pump 13 is 40.0% or more with respect to the average particle diameter D2 before the pump 13. From the viewpoint of improving the accuracy of controlling the particle size of the dispersed particles, it is preferably 50% or more, more preferably 65% or more, still more preferably 80% or more, and from the same viewpoint, preferably 130% or less, more preferably Is 125% or less, more preferably 120% or less. At the first distribution of the mixed liquid L to the external circulation line 12, the average particle diameter D3 after the pump 13 is preferably 50% or more and 130% or less, more preferably 65% with respect to the average particle diameter D2 before the pump 13. It is 125% or less, more preferably 80% or more and 120% or less.

  During the initial distribution of the liquid mixture L to the external circulation line 12, the average particle size D2 before the pump 13 and the average particle size D3 after the pump 13 increase the accuracy of particle size control of the dispersed particles by the static mixer 14. From the viewpoint, it is preferably 40 μm or more, more preferably 50 μm or more, further preferably 60 μm or more, and from the viewpoint of increasing the productivity of the emulsion by shortening the dispersion time, preferably 100 μm or less, more preferably 90 μm or less, More preferably, it is 80 μm or less. The average particle diameter D2 before the pump 13 and the average particle diameter D3 after the pump 13 are preferably 40 μm to 100 μm, more preferably 50 μm to 90 μm, and still more preferably 60 μm to 80 μm.

  The average particle size difference (D2−D3) obtained by subtracting the average particle size D3 after the pump 13 from the average particle size D2 before the pump 13 during the initial distribution of the mixed liquid L to the external circulation line 12 is a static mixer. From the viewpoint of improving the accuracy of controlling the particle size of the dispersed particles by No. 14, it is preferably 35 μm or less, more preferably 20 μm or less, and further preferably 10 μm or less.

  At the first distribution of the mixed liquid L to the external circulation line 12, the average particle diameter difference obtained by subtracting the average particle diameter D3 after the pump 13 from the average particle diameter D2 before the pump 13 with respect to the average particle diameter D2 before the pump 13 ( The pump diameter reduction ratio ((D2-D3) / D2) × 100 of D2-D3) is preferably 60% or less, more preferably from the viewpoint of improving the accuracy of particle size control of the dispersed particles by the static mixer 14. Is 40% or less, more preferably 20% or less.

  When the mixed liquid L first flows to the external circulation line 12, the average particle diameter D4 of the dispersed particles of the mixed liquid L after coming out of the stationary mixer 14 (hereinafter referred to as the "average particle diameter D4 after the stationary mixer 14"). Is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 35 μm or more from the viewpoint of improving the accuracy of particle size control of the dispersed particles by the static mixer 14, and shortens the dispersion time. From the viewpoint of enhancing the productivity of the emulsion, it is preferably 80 μm or less, more preferably 70 μm or less, and still more preferably 60 μm or less. The average particle diameter D4 after the static mixer 14 is preferably 20 μm or more and 80 μm or less, more preferably 30 μm or more and 70 μm or less, and further preferably 35 μm or more and 60 μm or less.

  When the mixed liquid L is first circulated to the external circulation line 12, the average particle size difference (D2-D4) obtained by subtracting the average particle size D4 after the static mixer 14 from the average particle size D2 before the pump 13 is dispersed. From the viewpoint of shortening the time and improving the productivity of the emulsion, it is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. Further, the accuracy of controlling the particle size of the dispersed particles by the static mixer 14 is improved. From the viewpoint of increasing, the thickness is preferably 70 μm or less, more preferably 60 μm or less, and still more preferably 50 μm or less. This average particle size difference (D2-D4) is preferably 5 μm or more and 70 μm or less, more preferably 10 μm or more and 60 μm or less, and further preferably 15 μm or more and 50 μm or less.

  At the first distribution of the mixed liquid L to the external circulation line 12, the average particle size obtained by subtracting the average particle size D4 after the stationary mixer 14 from the average particle size D2 before the pump 13 with respect to the average particle size D2 before the pump 13 The diameter reduction ratio (D2-D4) / (D2) × 100 of the diameter difference (D2-D4) is preferably 10% or more, more preferably from the viewpoint of shortening the dispersion time and increasing the productivity of the emulsion. 15% or more, more preferably 20% or more, and from the viewpoint of improving the accuracy of particle size control of the dispersed particles by the static mixer 14, it is preferably 70% or less, more preferably 60% or less, still more preferably 55% or less. This line diameter reduction rate is preferably 10% to 70%, more preferably 15% to 60%, and still more preferably 20% to 55%.

  During the initial distribution of the mixed liquid L to the external circulation line 12, the average particle diameter D5 of the dispersed particles of the mixed liquid L circulated through the external circulation line 12 and stored in the mixed liquid storage tank 11 (hereinafter referred to as “the mixed liquid storage tank 11 The average particle diameter D5 ”) is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 15 μm or more, from the viewpoint of increasing the accuracy of particle size control of the dispersed particles by the static mixer 14. From the viewpoint of shortening the dispersion time and increasing the productivity of the emulsion, it is preferably 70 μm or less, more preferably 60 μm or less, and still more preferably 50 μm or less. The average particle diameter D5 of the mixed liquid storage tank 11 is preferably 5 μm or more and 70 μm or less, more preferably 10 μm or more and 60 μm or less, and further preferably 15 μm or more and 50 μm or less.

  The linear velocity of the liquid mixture L in the portion where the flow path in the static mixer 14 is the narrowest is preferably 1.0 m / second or more, more preferably 2. from the viewpoint of shortening the dispersion time and improving the productivity of the emulsion. 0 m / sec or more, more preferably 3.0 m / sec or more, and preferably from the viewpoint of increasing the accuracy of particle size control of dispersed particles by the static mixer 14 by suppressing an increase in pressure loss. It is 10 m / second or less, more preferably 8.0 m / second or less, and still more preferably 6.0 m / second or less. The linear velocity of the mixed liquid L in the portion where the flow path in the static mixer 14 is the narrowest is preferably 1.0 m / second or more and 10 m / second or less, more preferably 2.0 m / second or more and 8.0 m / second or less. More preferably, it is 3.0 m / sec or more and 6.0 m / sec or less. In the static mixer 14 having the channel hole 143 as shown in FIG. 4, the narrowest part of the channel corresponds to the contracted portion 143 a of the channel hole 143. The linear velocity of the mixed liquid L can be obtained by dividing the flow rate by the total cross-sectional area of the contracted portion.

  The pressure loss between the inlet and the outlet of the static mixer 14 is 0 MPa or more, and preferably 2.0 MPa or less from the viewpoint of increasing the accuracy of particle size control of the dispersed particles by the static mixer 14. More preferably, it is 1.0 MPa or less, and further preferably 0.6 MPa or less.

  The temperature of the liquid mixture L at the time of dispersion by the static mixer 14 is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, and further preferably 15 ° C. or higher, from the viewpoint of dispersion operability and component solubility. In addition, from the same viewpoint, it is preferably 100 ° C. or lower, more preferably 40 ° C. or lower, and further preferably 30 ° C. or lower. The temperature of the liquid mixture L during dispersion by the static mixer 14 is preferably 5 ° C. or higher and 100 ° C. or lower, more preferably 10 ° C. or higher and 40 ° C. or lower, and further preferably 15 ° C. or higher and 30 ° C. or lower.

  The average number of circulations of the mixed liquid L to the external circulation line 12 only needs to reach a target particle size, and is preferably at least once, more preferably 2 from the viewpoint of forming an emulsion of dispersed particles having a uniform particle size. From the viewpoint of increasing the emulsion productivity by shortening the dispersion time, it is preferably 10 times or less, more preferably 8 times or less, and even more preferably 7 times or less. . The average number of circulations of the mixed liquid L to the external circulation line 12 is preferably 1 to 10 times, more preferably 2 to 8 times, and even more preferably 3 to 7 times.

  The average particle diameter D6 of the dispersed particles in the emulsion obtained in the mixed liquid storage tank 11 after being circulated a plurality of times to the external circulation line 12 of the liquid mixture L (hereinafter referred to as “average particle diameter D6 of the emulsion”) is the use of the emulsion. However, it is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, and preferably 60 μm or less, more preferably 50 μm or less, and even more preferably 40 μm or less. The average particle diameter D6 of the emulsion is preferably 1 μm to 60 μm, more preferably 5 μm to 50 μm, and still more preferably 10 μm to 40 μm. The average particle diameter D6 of this emulsion can be controlled by the average number of circulations of the mixed liquid L to the external circulation line 12. 2A and 2B, when the static mixer 14 is used, the average particle diameter D6 of the emulsion is determined by the average number of circulations of the mixed liquid L to the external circulation line 12 and the first and second elements 141. , 142 in combination with the number of units.

  The average particle size difference (D1-D6) obtained by subtracting the average particle size D6 of the emulsion from the initial average particle size D1 is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more. The total thinning ratio ((D1-D6) / D1) × 100 of the average particle size difference (D1-D6) obtained by subtracting the average particle size D6 of the emulsion from the initial average particle size D1 with respect to the initial average particle size D1 is: Preferably it is 50% or more, More preferably, it is 60% or more, More preferably, it is 70% or more.

  FIG. 6 shows a second emulsion production apparatus 10 that can be used in the emulsion production method according to the embodiment. In addition, the part of the same name as the 1st emulsion manufacturing apparatus 10 is shown with the same code | symbol as the 1st emulsion manufacturing apparatus 10. FIG.

  The second emulsion manufacturing apparatus 10 includes a mixed liquid storage tank 11, a recovered liquid storage tank 15, and a mixed liquid feeding line 16 that connects them. A pump 13 and a static mixer 14 are provided in this order from the mixed solution storage tank 11 side in the mixed solution feeding line 16.

  The recovered liquid storage tank 15 is constituted by a storage tank. The recovered liquid storage tank 15 may be provided with a stirring function and a temperature control function. The mixed liquid feeding line 16 is configured by a pipe that is provided so as to extend from the bottom of the mixed liquid storage tank 11 and is coupled to the upper part of the recovered liquid storage tank 15. The liquid mixture storage tank 11, the pump 13, and the static mixer 14 have the same configuration as that of the first emulsion production apparatus 10.

  In the second emulsion manufacturing apparatus 10, a mixed liquid L of an aqueous phase and an oil phase is charged into the mixed liquid storage tank 11. The pump 13 causes the liquid mixture L in the liquid mixture storage tank 11 to flow from the bottom of the liquid mixture storage tank 11 to the liquid mixture feed line 16 and then flows from the liquid mixture feed line 16 to the upper part of the recovered liquid storage tank 15. So that the liquid is fed. At this time, the static mixer 14 passes through the liquid mixture feed line 16 and passes through the static mixer 14 once to give shear to the liquid mixture L, thereby reducing the diameter of the dispersed particles. Let When the liquid mixture L is repeatedly passed through the stationary mixer 14, the liquid mixture L recovered in the recovered liquid storage tank 15 may be returned to the liquid mixture storage tank 11 and recirculated through the liquid mixture feeding line 16. .

  In the first and second emulsion production apparatuses 10, one static mixer 14 is interposed in the external circulation line 12 and the mixed liquid feeding line 16. However, the present invention is not particularly limited thereto. However, from the viewpoint of improving the dispersion performance of the mixed liquid, as shown in FIG. 7A, a plurality of static mixers 14 may be provided in series, and from the viewpoint of improving the processing performance of the mixed liquid L, As shown in FIG. 7B, a plurality of static mixers 14 may be provided in parallel.

  In the first and second emulsion production apparatuses 10, the static mixer 14 is provided on the downstream side of the pump 13. However, the present invention is not limited to this, and the upstream side of the pump 13 is not limited thereto. The structure provided with the static mixer 14 may be sufficient.

(Method for producing microcapsule particles)
The method for producing microcapsule particles according to the embodiment will be described using an oil-in-water emulsion as an example.

  In the microcapsule particle manufacturing method according to the embodiment, first, an oil-in-water emulsion is manufactured by the emulsion manufacturing method according to the embodiment.

  At this time, the content of the aqueous phase of the dispersion medium in the mixed liquid L charged into the mixed liquid storage tank 11 is preferably 55% by mass or more, more preferably 60% by mass or more, and still more preferably 65% by mass from the viewpoint of dispersion stability. From the same viewpoint, it is preferably 80% by mass or less, more preferably 75% by mass or less, and still more preferably 70% by mass or less. The content of the aqueous phase in the mixed liquid L is preferably 55% by mass to 80% by mass, more preferably 60% by mass to 75% by mass, and still more preferably 65% by mass to 70% by mass.

  The aqueous phase contains ion-exchanged water or distilled water as water. The aqueous phase preferably contains a dispersion stabilizer. Examples of the dispersion stabilizer include water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, and polyacrylic acid. The dispersion stabilizer is preferably used including one or more of these, and from the viewpoint of forming uniform microcapsule particles and improving productivity, it is preferable to use polyvinyl alcohol.

  The weight average molecular weight of polyvinyl alcohol is preferably 10,000 or more, more preferably 20,000 or more, still more preferably 30,000 or more, and still more preferably 40,000, from the viewpoints of forming uniform microcapsule particles and increasing productivity. From the same viewpoint, it is preferably 500,000 or less, more preferably 300,000 or less, still more preferably 200,000 or less, and still more preferably 150,000 or less. The weight average molecular weight of polyvinyl alcohol is preferably 10,000 or more and 500,000 or less, more preferably 20,000 or more and 300,000 or less, still more preferably 30,000 or more and 200,000 or less, and still more preferably 40,000 or more and 150,000 or less.

  The degree of hydrolysis of polyvinyl alcohol is preferably 60% / mol or more, more preferably 70% / mol or more, still more preferably 80% / mol or more, from the viewpoint of improving productivity while forming uniform microcapsule particles. More preferably, it is 85% / mol or more, and from the same viewpoint, it is preferably 100% / mol or less, more preferably 96% / mol or less, still more preferably 93% / mol or less, and still more preferably 90% or less. % / Mol or less. The degree of hydrolysis of polyvinyl alcohol is preferably 60% / mol to 100% / mol, more preferably 70% / mol to 96% / mol, and still more preferably 80% / mol to 93% / mol. More preferably, it is 85% / mol or more and 90% / mol or less.

  The content of the dispersion stabilizer in the aqueous phase is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and still more preferably 0, from the viewpoint of forming uniform microcapsule particles and increasing productivity. .15% by mass or more, more preferably 0.30% by mass or more, and from the same viewpoint, it is preferably 10.0% by mass or less, more preferably 5.0% by mass or less, still more preferably 3. 0% by mass or less. The content of the dispersion stabilizer in the aqueous phase is preferably 0.05% by mass to 10.0% by mass, more preferably 0.10% by mass to 5.0% by mass, and still more preferably 0.15% by mass. It is more than 3.0 mass%, More preferably, it is 0.30 mass% or more and 3.0 mass% or less.

  In addition, the content of the aqueous phase dispersion stabilizer in the mixed liquid L is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the oil phase, from the viewpoint of forming uniform microcapsule particles and increasing productivity. More preferably 1.0 parts by mass or more, still more preferably 1.5 parts by mass or more, still more preferably 2.0 parts by mass or more, and from the same viewpoint, preferably 15 parts by mass or less, more preferably It is 10 parts by mass or less, more preferably 8.0 parts by mass or less, and still more preferably 6.0 parts by mass or less. The content of the aqueous phase dispersion stabilizer in the mixed liquid L is preferably 0.5 parts by mass or more and 15 parts by mass or less, more preferably 1.0 parts by mass or more and 10 parts by mass or less, with respect to 100 parts by mass of the oil phase. More preferably, they are 1.5 mass parts or more and 8.0 mass parts or less, More preferably, they are 2.0 mass parts or more and 6.0 mass parts or less.

  From the viewpoint of dispersion stability, the content of the oil phase of the dispersed particles in the mixed liquid L charged into the mixed liquid storage tank 11 is preferably 15% by mass or more, more preferably 20% by mass or more, and further preferably 25% by mass or more. From the same viewpoint, it is preferably 45% by mass or less, more preferably 40% by mass or less, and still more preferably 35% by mass or less. The content of the oil phase in the mixed liquid L is preferably 15% by mass to 45% by mass, more preferably 20% by mass to 40% by mass, and further preferably 25% by mass to 35% by mass.

  The oil phase contains a vinyl monomer that forms a polymer constituting the shell of the microcapsule particles and an oil-soluble polymerization initiator. The content of the vinyl monomer in the oil phase is, for example, 5% by mass or more and 50% by mass or less. The content of the oil-soluble polymerization initiator in the oil phase is, for example, 0.01 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the vinyl monomer content in the oil phase.

  Examples of the vinyl monomer include acrylic acid and methacrylic acid (hereinafter referred to as “A monomer”), alkyl acrylate and alkyl methacrylate (hereinafter referred to as “B monomer”), acryloyl group or methacryloyl group. And a monomer derived from a crosslinkable monomer having 2 or more (hereinafter referred to as “C monomer”).

  Examples of the A monomer include acrylic acid and methacrylic acid. The A monomer is preferably used including one or two of acrylic acid and methacrylic acid. The content of the A monomer in the vinyl monomer is, for example, 30% by mass or more and 60% by mass or less.

  Examples of the B monomer include methyl acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and the like. The B monomer is preferably used including one or more of these. The content of the B monomer in the vinyl monomer is, for example, 5% by mass or more and 30% by mass or less.

  Examples of the C monomer include ethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and tetraethylene glycol dimethacrylate. The C monomer is preferably used including one or more of these. The content of the C monomer in the vinyl monomer is, for example, 20% by mass or more and 50% by mass or less.

  Examples of the oil-soluble polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), lauroyl peroxide, benzoyl peroxide, and the like. The oil-soluble polymerization initiator is preferably used including one or more of these.

  The oil phase contains an oil component that constitutes the core of the microcapsule particles. The content of the oil component in the oil phase is, for example, 50% by mass or more and 95% by mass or less.

  Examples of the oil component include a fragrance, a fragrance precursor, an oil agent, an antioxidant, a cooling agent, a dye, a pigment, a silicone, a solvent, and an oil-soluble polymer. The oil component is preferably used including one or more of these. The oil component preferably contains at least one of a fragrance and a fragrance precursor.

  Examples of the fragrance include hydrocarbon fragrance, alcohol fragrance, aldehyde fragrance, ketone fragrance, ester fragrance, phenol fragrance, ether fragrance, amine fragrance, lactone fragrance, acetal fragrance, and nitrile fragrance. Etc. It is preferable to use a fragrance | flavor including 1 type, or 2 or more types of these. The fragrance may be a natural fragrance or a synthetic fragrance. The perfume may be solid at normal temperature and pressure, or may be liquid at normal temperature and pressure. Examples of the fragrance precursor include a silicate ester obtained by transesterification of an alcohol fragrance or a phenol fragrance and an alkoxysilane, an ester of an alcohol fragrance or a phenol fragrance and a fatty acid having 6 to 24 carbon atoms. Etc. Content of the fragrance | flavor and / or fragrance | flavor precursor in an oil-based component is 50 to 100 mass%, for example. When including a fragrance | flavor in an oil-based component, it is preferable to also include a fatty acid ester from a viewpoint of improving the stability.

  Examples of the oil agent include those generally used in pharmaceuticals, quasi drugs, cosmetics, toiletries and the like such as higher alcohols, silicones, ether oils, ester oils and hydrocarbons. Examples of the antioxidant include sodium sulfite and sodium ascorbate. Examples of the solvent include those generally used in pharmaceuticals, quasi drugs, cosmetics, toiletries and the like such as alcohol.

  In the method for producing microcapsule particles according to the embodiment, after obtaining an oil-in-water emulsion in the mixed liquid storage tank 11 or the recovered liquid storage tank 15 from the mixed liquid L charged in the mixed liquid storage tank 11, this oil-in-water emulsion is used. Transfer to a reaction vessel equipped with a stirrer and temperature control function, and stir the oil-in-water emulsion in the reaction vessel, and inactive in the polymerization of vinyl monomers such as nitrogen gas in the gas phase in the reaction vessel Degas by introducing gas.

  And the temperature of an oil-in-water emulsion is raised. At this time, the vinyl monomer contained in the dispersed particles in the oil phase is polymerized to form a polymer to form a shell, and microcapsule particles in which the oil component of the core is encapsulated in the polymer shell are manufactured. . In addition, you may perform superposition | polymerization of this vinyl monomer in the liquid mixture storage tank 11 or the collection | recovery liquid storage tank 15 which obtained the oil-in-water emulsion.

  The polymerization temperature is preferably 40 ° C. or higher, more preferably 60 ° C. or higher, from the viewpoint of forming uniform microcapsule particles and increasing productivity, and from the same viewpoint, preferably 90 ° C. or lower, more preferably Is 80 ° C. or lower. The polymerization temperature is preferably 40 ° C. or higher and 90 ° C. or lower, more preferably 60 ° C. or higher and 80 ° C. or lower.

  The polymerization time is preferably 3 hours or more, more preferably 5 hours or more from the viewpoint of forming uniform microcapsule particles and reducing the residual monomer, and from the same viewpoint, preferably 9 hours or less, more Preferably it is 8 hours or less. The polymerization time is preferably 3 hours or more and 9 hours or less, more preferably 5 hours or more and 8 hours or less.

  The average particle diameter D7 of the produced microcapsule particles is preferably 1.00 μm or more, more preferably 2.00 μm or more, still more preferably 5.00 μm or more, still more preferably 10.0 μm or more, and preferably Is 60.0 μm or less, more preferably 50.0 μm or less, still more preferably 40.0 μm or less, and even more preferably 30.0 μm or less. The average particle diameter D7 of the produced microcapsule particles is preferably 1.00 μm or more and 70.0 μm or less, more preferably 2.00 μm or more and 50.0 μm or less, further preferably 5.00 μm or more and 40.0 μm or less, and even more. Preferably they are 10.0 micrometers or more and 30.0 micrometers or less.

  The content of the shell in the produced microcapsule particles is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, still more preferably 35 parts by mass or more, and still more preferably 40 parts by mass with respect to 100 parts by mass of the core. In addition, it is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 60 parts by mass or less, and still more preferably 50 parts by mass or less. The content of the shell in the produced microcapsule particles is preferably 20 parts by mass or more and 80 parts by mass or less, more preferably 30 parts by mass or more and 70 parts by mass or less, and further preferably 35 parts by mass or more with respect to 100 parts by mass of the core. 60 mass parts or less, More preferably, it is 40 mass parts or more and 50 mass parts or less.

  In the method for producing microcapsule particles according to the embodiment, an example in which an oil-in-water emulsion is used has been shown. However, the present invention is not particularly limited to this, and an aqueous phase containing a monomer in the oil phase Even when a water-in-oil emulsion in which dispersed particles are dispersed is used, microcapsule particles can be produced by the same operation.

(Manufacture of emulsion and microcapsule particles)
Production experiments of emulsions and microcapsule particles of Examples 1-2 and Comparative Examples 1-3 below were conducted. The contents of each are also shown in Table 1.

<Example 1>
An emulsion production apparatus 10 having the same configuration as shown in FIG. 1 was prepared. “Moono pump model: 2NL06F” manufactured by Hyojin Equipment Co., Ltd., which is a screw pump of a low shear pump as the pump 13, and “Dispersion-kun” manufactured by Fujikin Co., Ltd. as the static mixer 14 (5 units, the contraction part of the flow path hole 143 143a inner diameter d1: 0.5 mm and length l: 1.8 mm, and inflow portion 143b and outflow portion 143c opening diameter d2: 6 mm) were used, respectively.

  First, 686 g of ion-exchanged water was charged into a 1 L glass beaker, and while stirring this, polyvinyl alcohol (Gosenol GH-20 manufactured by Nippon Synthetic Chemical Co., Ltd., weight average molecular weight: 80,000, hydrolysis degree: 86.5) while stirring. 89.0% / mol) was added. Then, this mixed liquid was heated up to 85 ° C. and stirred for 2 hours to dissolve polyvinyl alcohol, thereby preparing 700 g of a 2.0 mass% polyvinyl alcohol aqueous solution. This was the aqueous phase.

  Also, in a 500 mL glass beaker, 157.5 g of alcohol-based fragrance I-menthol, fatty acid ester 2-ethylhexanoic acid triglyceride (trade name: Exepearl TGO) 52.5 g, A monomer methacrylic acid 40 1.0 g, B monomer 13.3 g, C monomer ethylene glycol dimethacrylate 35.5 g, and oil-soluble polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) 1.2 g (V-65, manufactured by Wako Pure Chemical Industries, Ltd.) was charged, and these were stirred at room temperature to dissolve I-menthol to prepare 300 g of a solution. This was the oil phase.

  In addition, content of the oil-based component which consists of 2-ethylhexanoic acid triglyceride of 2-ethylhexanoic acid of alcohol perfume and fatty acid ester in an oil phase is 66.7 mass%. Content of the vinyl monomer which consists of A monomer, B monomer, and C monomer in an oil phase is 29.6 mass%. The content of each of the A monomer, B monomer, and C monomer in the vinyl monomer is 45% by mass, 15% by mass, and 40% by mass. The content of the oil-soluble polymerization initiator in the oil phase is 1.4 parts by mass with respect to 100 parts by mass of the vinyl monomer.

  Next, an anchor in which 700 g of an aqueous phase and 300 g of an oil phase were combined and mixed in a 4000 ml SUS storage tank having a Dimroth cooler and mixed, and the mixture was rotated at a peripheral speed of 1.1 m / sec at room temperature. The mixture was preliminarily dispersed by stirring for 30 seconds with a blade (blade diameter 0.14 m) to prepare a mixed liquid in which dispersed particles of the oil phase were dispersed in the aqueous phase. The obtained liquid mixture was 1020 ml. Moreover, in this liquid mixture, content of the polyvinyl alcohol of the dispersion stabilizer of the water phase with respect to 100 mass parts of oil phases is 4.7 mass parts.

  Next, the preliminarily dispersed mixed liquid L is charged into the mixed liquid storage tank 11 of the emulsion production apparatus 10 and the pump 13 is operated at room temperature, whereby the mixed liquid L is fed at a flow rate of 200 mL / min, and the external circulation line The oil-in-water emulsion was obtained in the mixed liquid storage tank 11 by being circulated through the liquid 12 and circulated through the stationary mixer 14. The linear velocity of the mixed liquid L at the contracted flow portion 143a of the static mixer 14 was 3.8 m / sec, and the pressure loss between the inlet and the outlet of the static mixer 14 was 0.16 MPa. . The average circulation number of the mixed liquid L to the external circulation line 12 was set to 7 times.

  Then, the dissolved oxygen concentration is reduced by introducing nitrogen gas into the gas phase in the mixed liquid storage tank 11 and degassing, and the temperature of the oil-in-water emulsion is raised to 65 ° C. to form dispersed oil phase particles. The A monomer, B monomer, and C monomer contained therein were polymerized for 5 hours, and further heated to 75 ° C. for 3 hours. Then, it cooled to room temperature and obtained the suspension liquid which the microcapsule particle which included I-menthol in the core in a polymer shell disperse | distributed.

<Example 2>
The same operation as in Example 1 was performed except that an eccentric disk pump of Movex, which is a low shear pump, was used as the pump 13 and the flow rate of the mixed liquid L was 300 mL / min. The linear velocity of the mixed liquid L at the contracted flow portion 143a of the static mixer 14 was 5.7 m / sec, and the pressure loss between the inlet and the outlet of the static mixer 14 was 0.42 MPa. .

<Comparative Example 1>
Iwaki's magnet gear pump as the pump 13 and Fujikin's “Dispersion-kun” as the static mixer 14 (5 units, inner diameter d1: 1 mm and length l: 1.8 mm of the flow-reducing portion 143a of the channel hole 143) , The opening diameter d2 of the inflow part 143b and the outflow part 143c: 6.0 mm), the flow rate of the mixed liquid L is 1200 mL / min, and the average circulation number of the mixed liquid L to the external circulation line 12 is 1 Except for this, the same operation as in Example 1 was performed. The linear velocity of the mixed liquid L at the contracted flow part 143a of the static mixer 14 was 5.7 m / sec, and the pressure loss between the inlet and the outlet of the static mixer 14 was 0.30 MPa. .

<Comparative Example 2>
The same operation as in Comparative Example 1 was performed except that the flow rate of the mixed liquid L was 800 mL / min and the average number of circulation times of the mixed liquid L to the external circulation line 12 was three. The linear velocity of the mixed liquid L at the contracted flow portion 143a of the static mixer 14 was 3.8 m / sec, and the pressure loss between the inlet and the outlet of the static mixer 14 was 0.20 MPa. .

<Comparative Example 3>
The same operation as in Example 1 except that the static mixer 14 is not provided, the flow rate of the liquid mixture L is 300 mL / min, and the average number of times the liquid mixture L passes through the external circulation line 12 is 3 times. Went.

(Test method)
About each of Examples 1-2 and Comparative Examples 1-3, the liquid mixture L after preliminary dispersion was sampled from the storage tank made from SUS, and the initial average particle diameter D1 after preliminary dispersion was measured using it.

  For each of Examples 1 and 2 and Comparative Examples 1 to 3, when the average number of circulations was 1, the mixed liquid L before sampling and after exiting from the pump 13 was sampled and pumped using them. Average particle diameters D2 and D3 before and after 13 were measured. And the percentage ((D3 / D2) * 100) of the average particle diameter D3 after the pump 13 with respect to the average particle diameter D2 before the pump 13 was calculated. Further, an average particle size difference (D2-D3) obtained by subtracting the average particle size D3 after the pump 13 from the average particle size D2 before the pump 13 is calculated, and the average particle size with respect to the average particle size D2 before the pump 13 is calculated. The pump diameter reduction ratio ((D2-D3) / D2) × 100 of the diameter difference (D2-D3) was calculated.

  For each of Examples 1 and 2 and Comparative Examples 1 and 2, when the average number of circulations is 1, the mixed liquid L after exiting from the static mixer 14 is sampled, and using that, the static mixer 14 is sampled. The latter average particle diameter D4 was measured. And the average particle diameter difference (D2-D4) which subtracted the average particle diameter D4 after the static mixer 14 from the average particle diameter D2 before the pump 13 is calculated, and further, with respect to the average particle diameter D2 before the pump 13, The line thinning ratio ((D2-D4) / D2) × 100 of the average particle size difference (D2-D4) was calculated.

  About each of Examples 1-2 and Comparative Examples 1-3, the average particle diameter D5 of the liquid mixture storage tank 11 was measured when the average circulation frequency was 1 time.

  About each of Examples 1-2 and Comparative Examples 1-3, the liquid mixture L was circulated through the external circulation line 12 a predetermined number of times, and the oil-in-water emulsion obtained in the liquid mixture storage tank 11 was sampled and used in The average particle diameter D6 of the oil droplet type emulsion was measured. And the average particle diameter difference (D1-D6) which subtracted the average particle diameter D6 of the oil-in-water emulsion from the average particle diameter D1 after preliminary dispersion is calculated, and the average particle diameter D1 after preliminary dispersion is further calculated. The total diameter reduction ratio ((D1-D6) / D1) × 100 of the average particle diameter difference (D1-D6) was calculated.

  For each of Examples 1-2 and Comparative Examples 1-3, the suspension obtained in the mixed solution storage tank 11 after the polymerization was sampled, and the average particle diameter D7 of the microcapsule particles was measured using the sample.

  The average particle diameters D1 to D7 of the mixed liquid L and the dispersed particles of the oil-in-water emulsion and the microcapsule particles of the suspension are volume median diameters, and are laser diffraction / scattering particle size distribution measuring devices ( LA-960, manufactured by Horiba Ltd.).

(Test results)
The test results are shown in Table 1.

  According to Table 1, in Examples 1 and 2, the average particle diameter D3 after the pump 13 is larger than the average particle diameter D2 before the pump 13 by 115% and 94.3%, respectively. It can be seen that the effect on the particle size of the is small. Therefore, the particle size control of the dispersed particles by the static mixer 14 can be easily performed.

  On the other hand, in Comparative Examples 1 and 2, the average particle diameter D3 after the pump 13 is smaller than the average particle diameter D2 before the pump 13 by 6.03% and 15.0%, respectively. It can be seen that the effect on the diameter is large. In Comparative Example 3, the average particle diameter D3 after the pump 13 is as large as 107% with respect to the average particle diameter D2 before the pump 13, but the static mixer 14 is not provided, and the particle diameter of the dispersed particles is not provided. Control cannot be performed.

  INDUSTRIAL APPLICATION This invention is useful about the technical field of the manufacturing method of an emulsion, and the manufacturing method of a microcapsule particle using the same.

DESCRIPTION OF SYMBOLS 10 Emulsion manufacturing apparatus 11 Liquid mixture storage tank 11a Stirrer 12 External circulation line 13 Pump 14 Static mixer 141 1st element 142 2nd element 143 Channel hole 143a Constriction part 143b Inflow part 143c Outflow part 15 Recovery liquid storage tank 16 Mixing Liquid feed line L Mixed liquid

Claims (15)

A method for producing an emulsion in which a mixed liquid of an aqueous phase and an oil phase is circulated once or a plurality of times through a line provided with a pump and a static mixer,
Distribution of the mixed liquid to the line is the average of the dispersed particles of the mixed liquid after leaving the pump with respect to the average particle diameter of the dispersed particles in the mixed liquid before entering the pump at the first distribution. A method for producing an emulsion, wherein the particle size is controlled to be 40.0% or more.   Distribution of the mixed liquid to the line is the average of the dispersed particles of the mixed liquid after leaving the pump with respect to the average particle diameter of the dispersed particles in the mixed liquid before entering the pump at the first distribution. The method for producing an emulsion according to claim 1, wherein the particle size is controlled to be 130% or less.   The method for producing an emulsion according to claim 1 or 2, wherein the pump is a screw pump, an eccentric disk pump, a sine pump, or a peristaltic pump.   The method for producing an emulsion according to any one of claims 1 to 3, wherein an average particle diameter of the dispersed particles before the first distribution of the mixed liquid to the line is 40 µm or more and 100 µm or less.   The method for producing an emulsion according to any one of claims 1 to 4, wherein the mixed liquid is preliminarily dispersed before the first distribution of the mixed liquid to the line.   The method for producing an emulsion according to any one of claims 1 to 5, wherein the static mixer is provided on the downstream side of the pump.   From the stationary mixer from the dispersed particles in the mixed liquid before entering the pump, with respect to the average particle diameter of the dispersed particles in the mixed liquid before entering the pump, at the first flow of the mixed liquid to the line The line thinning ratio (((D2-D4) / D2) × 100) of the average particle size difference obtained by subtracting the average particle size of the dispersed particles of the mixed liquid after coming out is 10% or more and 70% or less. Item 7. A method for producing an emulsion according to Item 6.   The method for producing an emulsion according to any one of claims 1 to 7, wherein a linear velocity of the mixed liquid in a portion where the flow path in the static mixer is the narrowest is 1.0 m / sec or more and 10 m / sec or less.   The method for producing an emulsion according to any one of claims 1 to 8, wherein the line is a circulation line, and the mixed liquid is circulated through the circulation line.   The method for producing an emulsion according to any one of claims 1 to 9, wherein the emulsion is an oil-in-water emulsion.   The method for producing an emulsion according to claim 10, wherein the content of the oil phase in the mixed solution is 20% by mass or more and 45% by mass or less.   The method for producing an emulsion according to claim 10 or 11, wherein the oil phase contains a vinyl monomer.   The method for producing an emulsion according to claim 12, wherein the content of the vinyl monomer in the oil phase is 5% by mass or more and 50% by mass or less.   The method for producing an emulsion according to any one of claims 10 to 13, wherein the oil phase contains at least one of a fragrance and a fragrance precursor.   The manufacturing method of the microcapsule particle which polymerizes the said vinyl monomer, after obtaining the emulsion in which the said dispersion particle contains a vinyl monomer by the manufacturing method of the emulsion in any one of Claims 1 thru | or 14.

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