JP2012254431A - Method for manufacturing fine particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent rough particles from being mixed in fine particles to be manufactured.SOLUTION: A method for manufacturing fine particles includes: a step of forming liquid droplets by spraying raw material liquid into a gas phase inside a spraying tank 20, and cooling and solidifying the liquid droplets to obtain final particles; and a step of discharging the obtained fine particles from the spraying tank 20 after agitation with an agitator 10 established in the spraying tank 20, or while being agitated. The agitator 10 has no part hanging from above.

Description

  The present invention relates to a method for producing fine particles.

  A technique for obtaining fine particles by solidifying droplets formed by spraying a spray liquid is industrially adopted.

  For example, in Patent Document 1, a dispersion in which an oil component is dispersed in an aqueous component aqueous solution in which a gel-forming agent of a non-crosslinked hydrogel having a gel point of 30 ° C. or higher is sprayed into the gas phase, A method for producing hydrogel particles by cooling and solidifying the droplets formed thereby is disclosed.

JP 2007-160277 A

  By the way, when manufacturing microparticles by solidifying droplets formed by spraying a spray liquid in a spray tank, coarse particles may be mixed into a product.

  An object of the present invention is to suppress the mixing of coarse particles into the fine particles to be produced.

  The present invention includes a step of forming droplets by spraying a raw material liquid in a gas phase in a spray tank, and cooling and solidifying it to obtain fine particles, and the obtained fine particles are installed in the spray tank. The method for producing fine particles includes a step of discharging from the spray tank after stirring using the stirring means or under stirring conditions. The stirring means does not have a member that hangs down from above.

  According to the present invention, since the stirring means installed in the spray tank does not have a member that hangs down from above, mixing of coarse particles into the fine particles to be manufactured can be suppressed.

It is a longitudinal cross-sectional view which shows an example of the spray tank provided with the stirrer which does not have the member drooping from upper direction. It is a longitudinal cross-sectional view which shows another example of the spray tank provided with the stirrer which does not have the member drooping from upper direction. It is a longitudinal cross-sectional view which shows the spray tank provided with the stirrer which has the stirring shaft drooping from upper direction. 2 is an observation photograph of fine particles produced in Example 1 with an optical microscope. 4 is an observation photograph of fine particles produced in Comparative Example 1 with an optical microscope.

  Hereinafter, embodiments will be described in detail.

  The method for producing fine particles according to the present embodiment includes a step of forming droplets by spraying a raw material liquid in a gas phase in a spray tank, and cooling and solidifying the liquid droplets to obtain fine particles, and the obtained fine particles And a step of discharging from the spray tank after stirring using the stirring means installed in the spray tank or under stirring conditions. And the stirring means used at this time does not have the member which hangs down from upper direction.

<Raw material liquid>
In the method for producing fine particles according to this embodiment, examples of the raw material liquid used as the spray include a gel-forming agent-containing liquid and a solid fat-containing liquid.

-Liquid containing gel former-
The gel-forming agent-containing liquid is a liquid that contains a gel-forming agent and is adjusted to a temperature at least equal to or higher than its gelation point (freezing point). Examples of the gel forming agent-containing liquid include an aqueous component aqueous solution in which a gel forming agent that generates a non-crosslinked hydrogel is dissolved. And hydrogel particle is manufactured from the gel formation agent containing liquid of this aqueous component aqueous solution.

Examples of the gel forming agent that generates a non-crosslinked hydrogel include water-soluble polymers such as agar, carrageenan, gellan gum, xanthan gum, and high methoxyl pectin. Of these, agar is preferable, and agar having a jelly strength of 147 kPa (1500 g / cm ² ) or less is preferable from the viewpoint of good touch when the produced hydrogel particles are applied to, for example, cosmetics. Agar that is 19.6 kPa (200 g / cm ² ) to 127 kPa (1300 g / cm ² ) is more preferable. Here, “agar” in the present application refers to hemicellulose containing galactose composed of 1,3 bonds and 1,4 bonds of galactose. The jelly strength can be determined by the Nissho Water method. Specifically, the jelly strength is determined by measuring a Nissho water type jelly strength on a gel prepared by preparing a 1.5 mass% aqueous component aqueous solution of a gel forming agent and allowing the aqueous component aqueous solution to stand at 20 ° C. for 15 hours to solidify. The maximum mass (g) per surface area of 1 cm ² when the gel withstands the load at 20 ° C. for 20 seconds at 20 ° C. can be determined.

  The gel-forming agent that produces a non-crosslinked hydrogel preferably has a gelation point (freezing point) of 30 ° C. or higher from the viewpoint that it can be cooled and solidified at room temperature to produce hydrogel particles. More preferably, it is 30 degreeC, and it is more preferable that it is 30-45 degreeC. Here, the gelation point (freezing point) is about 10 ml of an aqueous component aqueous solution in which the gel is dissolved in a medium-sized test tube (diameter 1.5 cm × 16 cm), a thermometer is inserted, and the test tube is sometimes inclined at an angle. It can be calculated as the temperature at which the stub is fixed and cannot move.

  The gel forming agent-containing liquid may contain a single type of gel forming agent or a plurality of types of gel forming agent. The gel-forming agent-containing liquid preferably has a gel-forming agent concentration of 0.1 to 8.0% by mass, and more preferably 0.3 to 7.0% by mass. The temperature at which the gel forming agent is dissolved needs to be maintained at a temperature not lower than the melting temperature of the gel forming agent and not higher than the boiling point of water, but preferably 75 to 100 ° C. when the gel forming agent is agar. 80 to 100 ° C. is more preferable. In addition, you may pressurize and heat up to 100 degreeC or more in order to accelerate | stimulate melt | dissolution.

  The gel-forming agent-containing liquid may contain a water-soluble component such as catechin other than the gel-forming agent.

  In addition to the gel-forming agent, the gel-forming agent-containing liquid contains an inorganic solid such as titanium oxide or zinc oxide or an organic solid such as a water-insoluble complex composed of catechin and PVP (polyvinylpyrrolidone). Also good.

  In the gel-forming agent-containing liquid, an oily component may be dispersed in an aqueous component aqueous solution. That is, the gel-forming agent-containing liquid may be an O / W type dispersion.

  Oily components include solid fats and liquid oils. Here, “solid fat” in the present application refers to an oily component having a melting point of 35 ° C. or higher, and “liquid oil” refers to an oily component having a melting point of less than 35 ° C. As the solid fat, those described in paragraphs [0037] to [0044] of JP-A-2007-160277 can be used. For example, solid ceramide, solid sphingolipid, solid paraffin, solid high-grade oil can be used. Alcohol, petroleum jelly, solid silicone, solid oil agent, solid fragrance | flavor, etc. are mentioned. As the liquid oil, those described in paragraphs [0045] to [0047] of JP-A-2007-160277 can be used, and examples thereof include liquid skin protectants, liquid oil agents, liquid fragrances, and the like. Can be mentioned. In addition, as a specific example of solid fat and liquid oil, what is enumerated by the description about the solid fat containing liquid mentioned later is mentioned.

  The oil component may be composed of a single type of various solid fats and liquid oils, or may be composed of a plurality of types.

  From the viewpoint of suppressing leakage of the oil component from the produced hydrogel particles, the oil component preferably has a melting point of 35 ° C. or higher, more preferably 40 to 90 ° C., 45 It is more preferable to use a material having a temperature of ˜90 ° C., and particularly preferably a material having a temperature of 50 ° C. to 80 ° C. From the same viewpoint, when solid fat is included in the oil component, the solid fat preferably has a melting point of 40 to 120 ° C, more preferably 50 to 90 ° C, and more preferably 50 to 80 ° C. It is more preferable to use those. The melting point of the oil component can be measured by differential scanning calorimetry (DSC).

  The gel forming agent-containing liquid of the O / W type dispersion has a mass ratio (aqueous component aqueous solution / oil component) of the aqueous component aqueous solution to the oil component of, for example, 99/1 to 40/60. The gel forming agent-containing liquid of the O / W type dispersion may contain an emulsifier and / or a dispersant on at least one of the aqueous component side and the oily component side. As the emulsifier and / or dispersant, those described in paragraphs [0024] to [0034] of JP-A-2007-160277 can be used. For example, a polymer emulsifying dispersant, an anionic surfactant, Examples include cationic surfactants, nonionic surfactants, and amphoteric surfactants.

-Solid fat-containing liquid-
The solid fat-containing liquid is a liquid containing solid fat and adjusted to a temperature equal to or higher than its melting point. And oil-based component particle | grains are manufactured from this solid fat containing liquid.

  Examples of the solid fat include solid ceramide, solid sphingolipid, solid paraffin, solid higher alcohol, petrolatum, solid silicone, solid fragrance, and other solid fats. Of these, solid ceramide, solid higher alcohol, petrolatum, solid silicone, and solid fragrance are preferred from the viewpoint of skin protection when the produced oily component particles are applied to cosmetics and the like.

  Examples of the solid ceramide include N- (2-hydroxy-3-hexadecyloxypropyl) -N-hydroxyethyl hexadecanamide.

  Examples of the solid sphingolipid include phytosphingosine.

  Examples of the solid paraffin include paraffin wax, microcrystalline wax, and ceresin described in JIS K 2235.

  Examples of solid higher alcohols include cetyl alcohol, stearyl alcohol, arachidyl alcohol, and behenyl alcohol.

  Examples of the solid silicone include alkyl-modified silicone, polymer silicone / alkyl co-modified acrylic resin, and the like.

  Examples of other solid fats include hardened oils and higher fatty acids. Examples of the hardened oil include hardened oil whose raw material oil is palm oil, palm oil, and beef tallow. Examples of the higher fatty acid include palmitic acid, behenic acid, stearic acid, and the like.

  Examples of solid fragrances include menthol and cedrol.

  The solid fat preferably has a melting point of 40 to 120 ° C, more preferably 50 to 90 ° C, and further preferably 50 to 80 ° C from the viewpoint of suppressing dissolution of the oily component particles produced. preferable.

  The solid fat-containing liquid may contain a single type of solid fat or a plurality of types.

  The solid fat-containing liquid may be composed only of solid fat, or may contain liquid oil in addition to the solid fat. That is, the solid fat-containing liquid may be a mixed oil of solid fat and liquid oil.

  Examples of liquid oils include liquid skin protectants, liquid fragrances, and other liquid oils. Among these, a liquid skin protective agent is preferable from the viewpoint of skin protection when the produced oil component particles are applied to cosmetics and the like.

  A liquid skin protectant is a component that prevents rough skin by softening or smoothing the skin. Examples of liquid skin protectants include liquid oils such as liquid paraffin, liquid ester oil, liquid higher alcohol, liquid squalane and liquid glyceride; liquid ceramide such as cetyloxypropyl glyceryl methoxypropyl myristamide A liquid sphingolipid such as 1- (2-hydroxyethylamino) -3-isostearyloxy-2-propanol;

  Other liquid oils include, for example, liquid hydrocarbon oils; liquid vegetable oils; liquid fatty acids; liquid ethylene glycol difatty acid esters (fatty acids having 12 to 36 carbon atoms), liquid dialkyl ethers (having 12 carbon atoms). Liquid oils such as ˜36); liquid silicones and the like. The liquid oil agent may be volatile or non-volatile.

  The solid fat-containing liquid of the mixed oil is from the viewpoint of suppressing leakage of the liquid oil component from the produced oily component particles, and from the viewpoint of ease of spreading on the skin when the oily component particles are applied to cosmetics, etc. The mass ratio of solid fat to liquid oil (solid fat / liquid oil) is preferably 10/90 to 99/1, more preferably 20/80 to 80/20, and 20/80 to 70 /. 30 is more preferable, and 20/80 to 50/50 is most preferable.

  In the case of the solid fat-containing liquid of the mixed oil, the melting point of the mixed oil is preferably 35 ° C. or higher, from the viewpoint of suppressing leakage of the liquid oil component from the produced oil component particles, and is 40 to 90 ° C. More preferably, it is more preferably 45 to 90 ° C, and particularly preferably 50 to 80 ° C.

  The solid fat-containing liquid may contain an inorganic solid such as titanium oxide or zinc oxide dispersed by addition of a dispersant or a surface treatment, or an organic solid such as an organic pigment may be dispersed. It may be.

  An aqueous component may be dispersed in the solid fat-containing liquid. That is, the solid fat-containing liquid may be a W / O type dispersion.

  Examples of the aqueous component include aqueous solutions of water-soluble components such as catechin, aqueous dispersions of hydrophilic solids such as inorganic powders and inorganic fine particles, and the like. The aqueous component may be composed of a single species or a plurality of species.

  The mass ratio of the oil component to the aqueous component (oil component / aqueous component) in the solid fat-containing liquid of the W / O type dispersion is not particularly limited as long as the W / O type dispersion is maintained. 99/1, preferably 45/55 to 92.5 / 7.5, more preferably 50/50 to 90/10. The solid fat-containing liquid of the W / O type dispersion may contain an emulsifier and / or a dispersant on at least one of the oil component side and the aqueous component side.

<Spraying raw material liquid>
In the method for producing fine particles according to the present embodiment, when the raw material liquid is sprayed onto the gas phase in the spray tank, droplets are formed by the surface tension or interfacial tension.

Regarding the spray tank for spraying the raw material liquid, the volume is not particularly limited as long as unsolidified spray droplets do not adhere to the inner wall surface of the spray tank, but is, for example, 0.3 to 10 m ³ , and the temperature control function in the tank It is preferable to have. Further, 2 to 10 m ³ is preferable from the viewpoint of reducing aggregates.

  The aspect ratio (L / D) of the spray layer is preferably 0.6 to 4.0, and preferably 0.8 to 3.0, from the viewpoint of suppressing the formation of coarse particles by aggregation of unsolidified droplets. Is more preferable.

  Examples of the gas phase in the spray tank for spraying the raw material liquid include an atmospheric phase and a nitrogen gas phase. The temperature of the gas phase is the temperature at which the raw material liquid is cooled and solidified, and therefore is below the gel point when the raw material liquid is a gel-forming agent-containing liquid, and when the raw material liquid is a solid fat-containing liquid, The following. Specifically, for example, the outside air temperature (10 to 30 ° C.) is used.

  The spraying means for spraying the raw material liquid into the gas phase is not particularly limited, and examples thereof include use of a spray nozzle having spray holes provided downward or obliquely downward in the upper part of the spray tank.

  Examples of the spray nozzle include a one-fluid nozzle that sprays the raw material liquid alone and a two-fluid nozzle that mixes and sprays the raw material liquid with air or the like. A multi-nozzle system using two or more nozzles or an atomizer composed of two or more nozzles may be used. Further, from the viewpoint of suppressing coalescence of fine particles, it is preferable to use a fan nozzle or an empty cone nozzle having a large spray angle.

  The spray amount of the raw material liquid is preferably 2 to 400 kg / h per nozzle, more preferably 4 to 300 kg / h, and still more preferably 5 to 250 kg / h. When spraying the raw material liquid alone, the liquid pressure of the raw material liquid at the time of spraying is preferably 0.1 to 10 MPa from the viewpoint of promoting uniform droplet formation and suppressing coalescence of the droplets, It is more preferable to set it as 0.2-5 Mpa, and it is still more preferable to set it as 0.3-3 Mpa. In addition, when air and the like are mixed and sprayed, the liquid pressure is preferably 0.01 to 2 MPa from the viewpoint of promoting uniform droplet formation and suppressing coalescence of droplets. More preferably, the pressure is set to ˜1 MPa, and more preferably 0.05 to 0.5 MPa. The flow rate of air is preferably 10 to 4000 L / min, and more preferably 30 to 2500 L / min.

<Formation of fine particles>
In the method for producing fine particles according to the present embodiment, fine particles are obtained by cooling and solidifying the liquid droplets of the raw material liquid in the gas phase in the spray tank.

  The volume average particle diameter of the fine particles is preferably 10 to 800 μm, more preferably 15 to 600 μm, still more preferably 15 to 500 μm, and more preferably 20 to 400 μm from the viewpoint of appearance and productivity. It is particularly preferred. The volume-based average particle diameter of the fine particles can be measured by a laser diffraction / scattering method using a laser diffraction / scattering particle size distribution measuring apparatus.

  The shape of the fine particles is not particularly limited, but it is preferable to have a shape of a rotating body constituted by a curved surface. Here, the “rotary body constituted by a curved surface” means a closed figure constituted by a virtual axis and a continuous curve, rotated by the virtual axis, and has a shape such as a triangular pyramid or a cylinder. Is not included. The shape of the fine particles is more preferably a spherical body from the viewpoint of aesthetics.

<Discharge / collection of fine particles>
In the method for producing fine particles according to this embodiment, the obtained fine particles are discharged from the spray tank and collected after stirring using a stirring means installed in the spray tank or under stirring conditions.

  The stirring of the fine particles may be performed continuously in parallel with the spraying of the raw material liquid into the spray tank and the formation of the fine particles, and the batch of the raw material liquid sprayed into the spray tank and the formation of the fine particles. May not be stirred and may be done after all of it is complete.

  The discharging / collecting of the fine particles may be performed continuously in parallel with the stirring of the fine particles, or may be performed after stopping the stirring of the fine particles in a batch manner. If spraying of the raw material liquid into the spray tank and formation of fine particles, stirring of the fine particles, and discharging / collecting of the fine particles are performed in parallel, the fine particles can be produced in a continuous manner.

  The fine particles may be discharged and collected in the form of a slurry dispersion dispersed in a liquid dispersion medium. Such a slurry-like dispersion can be used as a master batch.

  The slurry-like dispersion can be obtained by adding a dispersion medium to the fine particles stored in the spray layer and stirring with a stirring means. The dispersion medium may be added in parallel with the spraying of the raw material liquid into the spray tank and the formation of the fine particles, or after the spraying of the raw material liquid into the spray tank and the formation of the fine particles are all completed. Also good. In addition, the slurry-like dispersion is prepared by preparing a dispersion medium in the spray tank in advance before spraying the raw material liquid into the spray tank, spraying the raw material liquid on the dispersion medium, and dispersing the fine particles directly into the liquid. It can also be obtained by collecting in a medium.

  Examples of the liquid dispersion medium include pure water, water containing a preservative, and the like.

  Examples of the preservative include parabens, 2-phenoxyethanol, alcohols such as ethanol and isopropanol, and polyhydric alcohols that are raw materials for increasing the antiseptic power.

  The mixing ratio (mass ratio) of the fine particles and the liquid dispersion medium is not particularly limited, but considering that the concentration ratio is effective as a master batch, the fine particles / dispersion medium = 100/0 to 20/80, Preferably it is 95 / 5-30 / 70, More preferably, it is 90 / 10-40 / 60.

<Agitating means of spray tank>
In the method for producing fine particles of the present embodiment, for example, a spray tank provided with stirring means for stirring the storage S such as a slurry dispersion is used, and the stirring means has a member that hangs down from above. Absent. Moreover, it is preferable that a stirring means has a stirring blade in the center part of a tank bottom from a viewpoint of performing mixing uniformly.

  Here, the member that hangs down from above in the stirring means is, for example, a suspension shaft that hangs down from the drive motor toward the bottom of the spray tank and that has a stirring blade attached to the tip or the like, and protrudes inward from the inner wall of the spray tank. A member exposed to the spraying space in a state where it comes into contact with droplets dropped from above and sprayed into the spray tank in the production process of fine particles, such as stationary blades such as baffle plates hanging downward.

  On the other hand, as a stirring means that does not have a member that hangs down from above, for example, as shown in FIGS. 1 and 2, the drive motor 12 and the drive source 16 are provided below the spray tank 20 to transmit power. Are not arranged in the gas phase space in the spray tank 20 where the droplets sprayed from the spray nozzle N at the top of the spray tank 20 are cooled and solidified, and only the bottom part of the spray tank 20 is used. The structure arrange | positioned in is mentioned. 1 and 2, parts having the same name are denoted by the same reference numerals.

  FIG. 1 shows an example of a spray tank 20 provided with a stirrer 10 (stirring means) that does not have a member hanging from above.

  The agitator 10 is provided with a bearing member 11 at the bottom center of the spray tank 20, and a stirring shaft 13 having one end coupled to the drive motor 12 is connected to the bearing member 11 via a seal member 14 and the other end is in the tank. On the other hand, a stirring blade 15 formed so as to extend along the bottom surface of the spray tank 20 is attached to the other end of the stirring shaft 13 exposed in the tank. The stirrer 10 is configured to rotate the stirring blade 15 through the stirring shaft 13 by the drive motor 12 and stir the storage S stored in the spray tank 20 with the stirring blade 15. As described above, in the agitator 10, the stirring shaft 13 is inserted from the bottom of the spray tank 20, and the entire configuration is provided on the bottom side of the spray tank 20, and thus does not have a member that hangs down from above.

  FIG. 2 shows another example of the spray tank 20 provided with a stirrer 10 (stirring means) that does not have a member that hangs down from above. The detailed structure of the stirrer 10 is disclosed in Japanese Patent Application Laid-Open No. 2007-29870.

  In the agitator 10, a driving-side rotor 17 connected to a driving source 16 is accommodated in a recess 21 that is immersed inside the bottom center of the spray tank 20. A bearing member 11 is provided on the upper surface inside the tank of the recess 21, and a stirring shaft 13 to which a stirring blade 15 is attached is rotatably supported on the bearing member 11. Further, the driven rotor 18 that is suspended so as to be disposed outside the recess 21 is coupled to the stirring blade 15. And this stirrer 10 carries out non-contact coupling | bonding between the magnet M in the drive side rotor 17 and the magnet M in the driven side rotor 18 through the side wall 21a of the recessed part 21 of the spray tank 20 by a magnetic coupling. A magnetic coupling drive transmission mechanism is formed, and the stirring blade 15 is rotationally driven without contact with the drive-side rotor 17 outside the spray tank 20 via this magnetic coupling drive transmission mechanism, and is stored in the spray tank 20. The storage S is configured to be stirred by the stirring blade 15. As described above, the agitator 10 is rotationally driven in a non-contact manner by the drive-side rotor 17 in which the stirring blade 15 is accommodated in the recess 21 at the bottom of the spray tank 20, and the entire configuration is also provided on the bottom side of the spray tank 20. Therefore, there is no member that hangs down from above.

  Other examples of the stirrer (stirring means) that does not have a member that hangs down from above include a magnetic stirrer, bubbling by introducing gas into the reservoir S, and the like.

  As described above, according to the method for producing fine particles according to the present embodiment, the stirrer 10 provided in the spray tank 20 does not have a member that hangs down from above, thereby suppressing the mixing of coarse particles into the produced fine particles. can do. The reason why the formation of coarse particles is suppressed by the configuration of the present invention is not necessarily clear, but it is assumed that the presence or absence of a member that hangs down from above such as a stirring shaft changes the flow of air in the spray tank. . That is, by not having a member that hangs down from above, it is possible to suppress the generation of air flow that causes the spray liquid to agglomerate and avoid the formation of coarse particles by collecting unsolidified droplets. It is believed that there is. As a further reason, the liquid droplets of the raw material liquid formed by being sprayed in the spray tank 20 adhere to a member that hangs down from above the stirring shaft or the like before solidification, and unsolidified liquid droplets gather to form coarse particles. It is considered that the formation is avoided.

According to the method for producing fine particles according to the present embodiment, since the stirring shaft 13 of the stirrer 10 is not disposed so as to hang down from the upper side to the axial position of the spraying tank 20, as shown in FIGS. The raw material liquid can be sprayed downward in the center of the top of the spray tank 20, and as a result, the sprayed liquid droplets fly in the same condition in the spray tank 20, and the cooling solidification history of the liquid droplets can be obtained. There is also an effect that it can be made uniform. Furthermore, adhesion of unsolidified spray droplets to the inner wall surface of the spray tank 20 is reduced, and the spray tank 20 can be made compact.
In the prior art, as shown in FIG. 3, a stirring shaft 13 having one end coupled to the drive motor 12 and a stirring blade 15 attached to the other end is disposed at the axial position of the spray tank 20, so The spray nozzle N to be sprayed must be provided at an eccentric position. In this case, the sprayed droplets have different flight distances depending on the flight direction, and therefore the cooling and solidification history of the droplets is not uniform.

(Method for producing microparticles for test evaluation)
The following test evaluation fine particles of Example 1 and Comparative Example 1 were produced.

<Example 1>
Sodium polyoxyethylene lauryl phosphate (trade name: SPE-104NB, manufactured by Kao Corporation), acrylic acid / alkyl methacrylate copolymer (trade name: PEMULEN TR-1 manufactured by Nikko Chemicals), methyl paraoxybenzoate, agar ( Manufactured by Ina Food Industry Co., Ltd., trade name: AX-200, jelly strength 19.6 kPa), sodium hydroxide, and ion-exchanged water 0.05: 0.01: 0.30: 3.00: 0.02: 74. Aqueous component aqueous solution mixed at a mass ratio of 12 and adjusted to 90 ° C. was prepared. In addition, N- (2-hydroxy-3-hexadecyloxypropyl) -N-hydroxyethylhexadecamide (trade name: sphingolipid E manufactured by Kao Corporation), dipentaerythritol fatty acid ester (manufactured by Nisshin Oilio Group Co., Ltd.) Name: Cosmol 168ARV), polyglyceryl diisostearate (trade name: Cosmol 42V manufactured by Nisshin Oillio Group), and methylpolysiloxane (trade name: Silicone KF-96A (10 cs) manufactured by Shin-Etsu Chemical Co., Ltd.) 10.00: 2 An oily component mixed at a mass ratio of .50: 5.00: 5.00 and adjusted to 80 ° C. was prepared. The composition of the aqueous component aqueous solution and the oil component is also shown in Table 1.

  After the aqueous component aqueous solution is cooled to 80 ° C., the oil component and the aqueous component aqueous solution are adjusted to 80 ° C. so that the mass ratio is oil component / aqueous component aqueous solution = 22.5 / 77.5 and the total is 20 kg. The mixed solution of the oily component and the aqueous component aqueous solution was prepared.

  Next, this mixed solution was transferred to an emulsifier (trade name: TK homomixer MARK II 40 type, manufactured by Tokushu Kika Co., Ltd.) adjusted to 80 ° C., and operated for 15 minutes at a rotational speed of 5500 r / min, and O / W A mold dispersion was prepared. The viscosity of the O / W type dispersion was 60 mPa · s.

  And with this O / W type dispersion liquid adjusted to 80 ° C., using a spray nozzle (trade name: SUE28B manufactured by Spraying Systems Japan Co., Ltd.), the liquid flow rate is 30.0 kg / h and the air pressure is 0.5 MPa. In the tank at room temperature, 10 kg was sprayed vertically downward into the gas phase from the top of the tank.

  The spray tank used at this time has the same configuration as shown in FIG. 1 and has a height of 1.9 m and a diameter of 1.8 m, and a bearing member is provided at the center of the bottom of the spray tank. In addition, a stirring shaft having one end coupled to the drive motor is inserted and supported through a seal member so that the other end is exposed in the tank, while the other end of the stirring shaft exposed in the tank is connected to the other end of the spray tank. A stirring blade formed so as to extend along the bottom surface is attached.

  After spraying, 300 kg of ion-exchanged water was poured into the tank, mixed uniformly with a stirring blade, and then recovered as a fine particle slurry. The production of these fine particles (hydrogel particles) was taken as Example 1.

<Comparative Example 1>
The spray tank has the same configuration as that shown in FIG. 3, and has a stirring shaft having a height of 1.9 m and a diameter of 1.8 m, one end coupled to the drive motor and a stirring blade attached to the other end. Fine particles were produced in the same manner as in Example 1 except that the one disposed at the position was used and the position of the spray nozzle was changed to a position eccentric from the center of the spray tank top as shown in FIG. This was designated as Comparative Example 1.

(Test evaluation method)
For each of the fine particle slurries of Example 1 and Comparative Example 1, the shape of the fine particles was observed using an optical microscope (trade name: Digital Microscope VHX-100F, manufactured by KEYENCE).

(Test evaluation results)
FIG. 4 shows the fine particles produced in Example 1. FIG. 5 shows the fine particles produced in Comparative Example 1.

  In the particle shape observation with an optical microscope, uniform fine particles could be obtained in Example 1 using a spray tank without a stirring axis in the spray space, but a spray tank having a stirring shaft in the spray space was used. In Comparative Example 1, coarse particles in which a plurality of fine particles were aggregated were mixed, and uniform fine particles could not be obtained.

  The present invention is useful for a method for producing fine particles.

10 Stirrer (stirring means)
DESCRIPTION OF SYMBOLS 11 Bearing member 12 Drive motor 13 Stirring shaft 14 Sealing member 15 Stirring blade 16 Drive source 17 Drive side rotor 18 Driven side rotor 20 Spraying tank 21 Recessed part 21a Partition M Magnet N Spray nozzle (spraying means)
S storage

Claims (4)

A step of forming droplets by spraying the raw material liquid into the gas phase in the spray tank, and cooling and solidifying it to obtain fine particles;
The step of discharging the fine particles obtained above from the spray tank after stirring using stirring means installed in the spray tank or under stirring conditions;
A method for producing fine particles having
The said stirring means is a manufacturing method of microparticles | fine-particles which do not have the member drooping from upper direction.   The fine particle production according to claim 1, wherein spraying means for spraying the raw material liquid into the gas phase in the spray tank is provided at the center of the top of the spray tank so as to spray the raw material liquid downward. Method.   The method for producing fine particles according to claim 1 or 2, wherein the raw material liquid is a gel-forming agent-containing liquid containing a gel-forming agent.   The method for producing fine particles according to any one of claims 1 to 3, wherein the fine particles are discharged from the spray tank in the form of a slurry dispersion in which the fine particles are dispersed in a dispersion medium.