JP2005194425A - Method for producing fine particle and fine particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing fine particles by which non-spherical fine particles having extremely uniform shape and size in which cross sections have an arbitrary shapes such as circular, elliptical, polygonal, starlike or infinite form, can readily, efficiently and continuously be produced, and to provide fine particles produced by the method for producing the fine particles. <P>SOLUTION: The method for producing the fine particles comprises solidifying a disperse phase 6 composed of a liquid 5 solidified by reaction while charging dispersion obtained by dispersing the disperse phase 6 into a continuous phase 2 in which the disperse phase 6 is not substantially mixed with the liquid into a passage 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention is produced by a method for producing fine particles having a uniform shape and size, and capable of producing non-spherical fine particles easily and efficiently, and a method for producing the fine particles. It relates to fine particles.

Fine particles made of resin or the like are widely used in the chemical, medical, electronic material fields and the like. For example, conductive fine particles in which a metal conductive layer is provided on the surface of fine particles made of resin are used as an anisotropic conductive material for conducting conductive connection between electronic components such as IC chips.
In recent years, as the application range of these fine particles expands, fine particles having a very uniform particle diameter and the like have been demanded. In addition, depending on the application, such as for conductive fine particles, not only conventional spherical fine particles but also non-spherical fine particles such as an elliptical shape and a cubic shape have been demanded. Moreover, such non-spherical fine particles are also required to have a uniform shape and size at a high level.

As a method for producing resin fine particles, for example, a suspension polymerization method is known. In the suspension polymerization method, an aqueous medium in which a dispersion stabilizer is dissolved is charged into a reaction vessel equipped with a stirrer, and a polymerizable monomer in which a polymerization initiator is dissolved is charged and heated while stirring the aqueous medium. This is a method for obtaining resin fine particles by polymerizing a polymerizable monomer. However, the particle size distribution of the resin fine particles obtained by the suspension polymerization method is wide, and in applications where the particle size of the resin fine particles is required to be precise, such as column fillers, spacers, toners, foams, etc. A separate operation was required, which was very complicated.

Therefore, an emulsion polymerization method using an emulsifying means such as a high-speed stirrer, a homogenizer, or an in-line mixer has been proposed in order to adjust the particle size more uniformly. According to the emulsion polymerization method, resin fine particles having a uniform particle diameter can be obtained as compared with the suspension polymerization method. However, even in the emulsion polymerization method, since the region where the shearing force is applied by the emulsifying means such as a high-speed stirrer, homogenizer, and in-line mixer is limited to the vicinity of the emulsifying blade, the shearing force is uneven depending on the distance from the emulsifying blade Thus, there is a problem that the particle size distribution of the dispersed dispersed phase is widened, and the particle size distribution of the resin fine particles obtained is also widened.

As a method for continuously producing particles, for example, Patent Document 1 describes a method for continuously producing silica gel and resin particles using a micromixer. In this method, an emulsion is prepared by mixing raw materials with a micromixer, and a polymerization reaction is advanced by a reaction tube and a post-reaction zone connected to the micromixer.
However, in the technique described in Patent Document 1, although particles having a uniform particle size can be obtained to some extent, in applications where strict uniformity is required, it is necessary to further uniform the particle size by post-treatment such as classification. .

On the other hand, for non-spherical fine particles, the shape of each fine particle can be controlled fairly precisely, but none can be said to be uniform as an aggregate of several hundred or more. Patent Document 2 discloses a monomer mixture containing a (meth) acrylic acid ester monomer as a main component and a crosslinkable vinyl monomer in the presence of seed particles composed of vinyl polymer fine particles.
Disclosed is a method for producing flat, irregularly shaped microparticles that are emulsion-polymerized in an aqueous medium in the absence of a water-insoluble organic solvent using a water-soluble polymerization initiator. This method utilizes polymerization shrinkage during polymerization, and flat microparticles resembling erythrocytes are obtained. However, the shape of the fine particles obtained by this method is limited to a flat shape, and the shape and particle size of the obtained fine particles are not uniform.

US Pat. No. 6,492,471 Japanese Patent No. 3340197

In view of the above, the present invention provides a method for producing fine particles having uniform shape and size and capable of producing non-spherical fine particles easily and efficiently, and production of the fine particles. It aims at providing the microparticles | fine-particles manufactured by the method.

The present invention relates to a method for producing fine particles in which a dispersed phase composed of a liquid that is solidified by a reaction is dispersed in a continuous phase that is substantially immiscible with the liquid, and the dispersed phase is solidified while flowing into the flow path. is there.
The present invention is described in detail below.

In the method for producing fine particles according to the present invention, the dispersed phase is solidified while flowing the dispersed liquid in the continuous phase in which the dispersed phase composed of the liquid solidified by the reaction is substantially immiscible with the liquid. .
As the fine particles produced by the method for producing fine particles of the present invention, from the dispersed phase (solution) state,
There is no particular limitation as long as it is known to be obtained from an emulsion state, for example, inorganic fine particles such as silica, and organic (resin such as styrene and acrylic). ) Fine particles. Especially, the manufacturing method of the microparticles | fine-particles of this invention is suitable for manufacturing the resin microparticles | fine-particles used in field | areas, such as a chemistry, a medical treatment, and an electronic material.
By using a polymerizable monomer as a liquid that is solidified by the reaction, resin fine particles can be produced by the method for producing fine particles of the present invention, and by using a photopolymerization initiator or a thermal polymerization initiator in combination, The dispersed phase composed of the polymerizable monomer can be polymerized and solidified by heat or active light.

The polymerizable monomer is not particularly limited, and examples thereof include those that can be conventionally polymerized by a suspension polymerization method or the like. When the present invention is carried out by dispersing a lipophilic dispersed phase in a hydrophilic continuous phase (hereinafter also referred to as an oil-in-water system), examples of the polymerizable monomer include styrene, vinyl naphthalene, alkyl-substituted styrene, etc. Monovinyl aromatic compounds such as bromo- or chloro-styrene; halo-substituted styrenes such as bromo- or chloro-styrene; polyvinyl aromatic compounds such as divinylbenzene, divinyltoluene, divinylxylene, divinylnaphthalene, trivinylbenzene, divinyldiphenylether, divinyldiphenylsulfone; Haloolefins, vinyl halides; esters of α-β-ethylenically unsaturated carboxylic acids such as esters of acrylic acid or methacrylic acid, and oil-soluble polymerizable monomers such as methyl methacrylate, ethyl acrylate, vinyl acetate. . These may be used independently and 2 or more types may be used together.

When the present invention is carried out by dispersing a hydrophilic dispersed phase in an oleophilic continuous phase (hereinafter also referred to as a water-in-oil system), examples of the polymerizable monomer include acrylamide, methacrylamide, and fumaramide. Water-soluble polymerizable monomers such as ethylenically unsaturated carboxamides such as ethacrylamide, aminoalkyl esters of unsaturated carboxylic acids and acid anhydrides, ethylenically unsaturated carboxylic acids such as acrylic acid and methacrylic acid can be used. .

When the liquid solidified by the reaction is composed of a polymerizable monomer, it is preferable that a polymerization initiator is contained in the dispersed phase or the continuous phase.
The polymerization initiator is not particularly limited and includes conventionally known ones. When the present invention is carried out in an oil-in-water system, for example, benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, potassium persulfate, azobis Examples thereof include oil-soluble polymerization initiators such as isobutyronitrile and azobisvaleronitrile. When the present invention is carried out in a water-in-oil system, examples of the polymerization initiator include water-soluble polymerization initiators such as persulfate, hydrogen peroxide, and hydroperoxide.
In addition, according to the means for polymerizing the polymerizable monomer, a known polymerization aid such as a photopolymerization initiator or a chain transfer agent may be used in combination. Further, other sensitizers, solvents, surfactants for adjusting the surface tension and the like may be used in combination as long as they do not affect the polymerization of the polymerizable monomer.

In the method for producing fine particles of the present invention, the dispersed phase is solidified while a dispersion dispersed in a continuous phase that is substantially immiscible with the liquid that is solidified by the reaction is flowed into the flow path.
The continuous phase is not particularly limited as long as it is substantially immiscible with the liquid that is solidified by the reaction, and is appropriately determined according to the type of liquid that is solidified by the reaction.
In the present invention, the phrase “substantially not miscible” means that the degree of miscibility is, for example, in the order of ppm.

When the method for producing fine particles of the present invention is carried out in an oil-in-water system, water is usually used as the continuous phase.
In this case, it is preferable to add a dispersion stabilizer so as not to split or coalesce the dispersed phase.
Examples of the dispersion stabilizer include cellulose such as polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose, and hydroxymethyl cellulose, water-soluble polymers such as starch and gelatin, and poorly water-soluble inorganic salts such as tricalcium phosphate.
In addition, a surfactant for adjusting surface tension, a specific gravity adjusting agent, and the like may be added to the continuous phase.

Further, when the method for producing fine particles of the present invention is carried out in a water-in-oil system, examples of the continuous phase include aliphatic hydrocarbons such as n-hexane and n-octane; halogenated carbonization such as carbon tetrachloride. Hydrogen-based; aromatic hydrocarbons such as toluene and xylene are included.
In this case, for example, sodium alkylbenzene sulfonate may be added as a surfactant.

The flow path for flowing the dispersion is not particularly limited. For example, the cross-sectional shape is a circle, an ellipse, a polygon,
Examples include a tubular member having an arbitrary shape such as a star shape or an indefinite shape.

In the method for producing fine particles of the present invention, the liquid that is solidified by the reaction may be prepared by previously dispersing in a continuous phase to prepare a dispersion, and flowing the dispersion into the flow path. But,
In the continuous phase flowing in the flow path, the dispersed phase composed of the liquid that solidifies by the reaction,
It is preferable to disperse the liquid by discharging it from an opening connected to the flow path. By making the discharge amount of the dispersed phase into the continuous phase flowing in the flow path constant, the volume of the produced fine particles can be made constant, and fine particles having a uniform shape and size can be produced reliably. Because. Further, the apparatus can be simplified because only the flow paths need to be combined.

FIG. 1 is a cross-sectional view schematically showing how a dispersed phase is added to a flow path through which a continuous phase flows in the method for producing fine particles of the present invention.
As shown in FIG. 1, an opening 3 is provided in a tubular flow channel 1 through which a continuous phase 2 flows, and a liquid 5 that solidifies by reaction is supplied to the flow channel 1 in the opening 3. The tubular supply pipe 4 is connected. That is, a predetermined amount of the liquid 5 discharged from the supply pipe 4 through the opening 3 into the flow path 1 is cut off at the portion of the opening 3 by the flow of the continuous phase 2, so that the dispersed phase 6 in the flow path 1. Is formed.

In the method for producing fine particles of the present invention, it is preferable that at least the dispersion in the flow path when solidifying the dispersed phase is a laminar flow. In this case, the liquid that is solidified by the reaction has a substantially uniform pressure applied from the continuous phase when solidified in the flow path, and as a result, the shapes of the produced fine particles are very uniform. It will be.
In order to make the dispersion flowing through the flow path laminar, it is sufficient to reduce the Reynolds number of the dispersion flowing through the flow path. Various methods are conceivable, but a method of narrowing the flow path is simple. is there.

In the method for producing fine particles of the present invention, the equivalent diameter of the flow path when solidifying the dispersed phase is 1 mm.
Or less, more preferably 0.5 mm or less, and still more preferably 0.
2 mm or less. By setting the equivalent diameter of the channel to 1 mm or less, the dispersion flowing in the channel can be made almost laminar.
The equivalent diameter is also called an equivalent (straight) diameter and is a term used in the field of mechanical engineering. When an equivalent circular pipe is assumed for a pipe having an arbitrary cross-sectional shape (a flow path in the present invention), the diameter of the equivalent circular pipe is called an equivalent diameter, which is defined by the following formula (1).

d _eq = 4 A / p (1)

In the above formula (1), d _eq represents the equivalent diameter, A represents the cross-sectional area of the pipe, and p represents the wetted length (circumferential length) of the pipe.

If the flow path is a circular pipe, the equivalent diameter matches the diameter of the circular pipe, and this equivalent diameter is used to estimate the flow or heat transfer characteristics of the flow path based on the data of the equivalent circular pipe. And represents the spatial scale (typical length) of the phenomenon. For example, the equivalent diameter d _e of a side length of square tubes of a
_{q ^{is, d eq = 4a 2 / 4a}} = a , and the equivalent diameter _{d eq} of an equilateral triangle tube side a, _{d e
q} = a / ^3-2 , and the equivalent diameter d _eq is d _eq = 2 in the flow between the parallel plates with the path height h.
(Refer to “Mechanical Engineering Dictionary” edited by the Japan Society of Mechanical Engineers, 1997, Maruzen).

When the liquid solidified by the reaction is composed of the above-described polymerizable monomer, resin fine particles are produced by polymerizing the dispersed phase composed of the polymerizable monomer.
When the polymerizable monomer is polymerized by heat, a thermal polymerization initiator is added to the dispersed phase in advance, and the polymerized monomer is continuously polymerized by heating the dispersed phase composed of the polymerizable monomer by a heating mechanism such as a heater. Resin fine particles can be continuously produced. In this case, the resin fine particles produced may be transferred to a reaction tank with a stirring function and heated in the reaction tank for further polymerization.
Further, when the dispersed phase composed of the polymerizable monomer is polymerized by light, the dispersed phase includes:
A photopolymerization initiator is added in advance, and the resin is continuously polymerized by irradiating the above-mentioned flow path with an actinic ray such as ultraviolet rays, whereby resin fine particles can be continuously produced.

According to the method for producing fine particles of the present invention, fine particles can be produced easily and efficiently continuously because the fine particles are produced by reacting a dispersed phase comprising a liquid that is solidified by reaction in the dispersion. be able to. In particular, when the equivalent diameter of the flow path when solidifying the dispersed phase is 1 mm or less, the pressure that the dispersed phase receives from the continuous phase during the reaction becomes uniform, so the shape and size are very uniform. Fine particles can be easily and efficiently produced continuously.

In the method for producing fine particles of the present invention, the shape of the cross section perpendicular to the flow direction of the dispersion liquid in the flow path (hereinafter, also simply referred to as the cross section of the flow path) and the dispersed phase composed of the liquid solidified by the reaction are obtained. By appropriately changing or controlling the volume, it is possible to easily and efficiently continuously produce spherical or non-spherical fine particles having a uniform shape and size.
In this case, the change in the cross-sectional shape of the flow path may be performed at least in the portion where the dispersed phase is reacted, and the cross-sectional shape of the entire flow path is not necessarily changed.

In the method for producing fine particles of the present invention, the volume diameter of the dispersed phase composed of the liquid solidified by the reaction is adjusted to be smaller than the diameter of the maximum circle that can be drawn inside the cross section of the flow path. Thus, spherical particles can be easily and efficiently produced continuously.
In this case, since the dispersed phase becomes a sphere having a minimum surface tension in the continuous phase flowing in the flow path, true spherical particles are produced.
The “volume diameter” means the diameter of a true sphere corresponding to the volume of the dispersed phase.

On the other hand, in the method for producing fine particles of the present invention, the volume diameter of the dispersed phase composed of the liquid that is solidified by the reaction is adjusted so as to be larger than the area diameter of the cross section of the flow path. Fine particles can be easily and efficiently produced continuously.
In this case, since the disperse phase spreads over the entire cross section of the flow path, the produced fine particles are elongated, and the cross section perpendicular to the longitudinal direction has substantially the same shape as the cross section of the flow path. It becomes.
The “area diameter” means the diameter of a perfect circle corresponding to the cross-sectional area of the flow path.

2-5 is a figure which shows typically the flow path used when manufacturing non-spherical microparticles | fine-particles with the manufacturing method of the microparticles | fine-particles of this invention, and the microparticles | fine-particles manufactured, (a) in each figure. These are sectional drawings which show the cross-sectional shape of the direction perpendicular | vertical to the flow of the dispersion liquid of a flow path, (b) is a front view of the microparticles | fine-particles manufactured, (c) is a top view of microparticles | fine-particles.

As shown in FIG. 2 (a), when a dispersed phase is added to the flow channel 20 having a substantially square cross-sectional shape, the volume diameter is larger than the area diameter of the cross-section of the flow channel 20, the produced fine particles are Like the fine particles 21 shown in (b) and (c), it has an elongated shape with a substantially square shape when viewed from the front.

Further, as shown in FIG. 3 (a), fine particles produced by adding a dispersed phase in an amount that makes the volume diameter larger than the area diameter of the cross section of the flow path 30 to the flow path 30 having a substantially rectangular cross section. (B
) And a fine particle 31 shown in FIG.

Further, as shown in FIG. 4A, when a dispersed phase is added to the flow path 40 having a circular cross-sectional shape, the volume diameter is larger than the area diameter of the cross section of the flow path 40 (diameter of the cross section itself). The fine particles to be produced have a long and narrow shape (a bowl shape) that is substantially circular when viewed from the front, like the fine particles 41 shown in FIGS.

Further, as shown in FIG. 5 (a), when the dispersed phase is added to the flow channel 50 having a substantially triangular cross section, the volume diameter is larger than the area diameter of the cross section of the flow channel 50, the fine particles produced. (B
) And a fine particle 51 shown in FIG.

Conventionally, it has been difficult and easy to produce non-spherical fine particles easily and efficiently continuously, but according to the method for producing fine particles of the present invention, non-spherical fine particles can be easily produced. In addition, it can be produced efficiently and continuously, and further, by carrying out the reaction of the dispersed phase in a laminar flow as described above, non-spherical fine particles having a very uniform shape and size can be easily obtained. And it can manufacture efficiently and continuously.

The fine particles produced by the fine particle production method of the present invention are also one aspect of the present invention.
In the following description of the fine particles of the present invention, the fine particles mean an aggregate of at least several hundred fine particles unless otherwise specified.

The fine particles of the present invention preferably have a volume diameter variation coefficient of 10% or less. In the fine particles of the present invention, the volume diameter means the diameter of a true sphere corresponding to the volume of each fine particle, and thus the volume diameter is a value that means the size of the fine particles. If the coefficient of variation of the volume diameter exceeds 10%, the sizes of the fine particles are not uniform and may not be used for applications such as conductive fine particles. Especially, when the shape of the fine particles of the present invention is spherical, the volume diameter variation coefficient is preferably 1% or less.

The fine particles of the present invention are preferably substantially similar. That is, when arbitrary fine particles selected from an aggregate of several hundred or more fine particles are compared with each other, the shapes are preferably substantially the same.
Therefore, it can be said that the fine particles of the present invention are aggregates of fine particles having extremely uniform shapes and sizes.

The shape of the fine particles of the present invention may be spherical or non-spherical. In the case of a non-spherical shape, examples of the cross section perpendicular to the longitudinal direction of the fine particles include arbitrary shapes such as a circle, an ellipse, a polygon, and a star.
In addition, non-spherical fine particles produced by the method for producing fine particles of the present invention are also one aspect of the present invention.

Since the fine particles of the present invention are produced by the method for producing fine particles of the present invention, they can be produced easily and efficiently continuously, regardless of whether they are spherical or non-spherical. Also,
If the fine particles of the present invention are produced by carrying out a reaction of a dispersed phase consisting of a liquid that solidifies by reaction in a dispersion flowing in a substantially laminar flow, the shape and size are extremely uniform, In the medical and electronic material fields, etc., it can be suitably used for applications requiring strict uniformity in shape and size. Among these, it is particularly suitable as a base particle for conductive fine particles.
Conductive fine particles comprising substrate particles comprising the fine particles of the present invention and a conductive layer formed on the surface of the substrate particles are also one aspect of the present invention.

The conductive fine particles of the present invention may be spherical, but are preferably non-spherical.
When conducting conductive connection using conductive fine particles, it is considered preferable to use non-spherical conductive fine particles because a sufficient contact area with the electrode can be obtained compared to the case of using spherical conductive fine particles. In the prior art, non-spherical conductive fine particles having a uniform size and shape could not be produced. In the conductive fine particles of the present invention, by using the fine particles of the present invention as the base material particles, the size and shape can be sufficiently obtained and can be put to practical use.

Such non-spherical conductive fine particles preferably have, for example, a shape having a substantially flat plane portion on at least a part of the surface.
In the present specification, the plane portion is substantially flat. The plane portion has slight irregularities and curvatures when viewed strictly, but is compared with a portion other than the plane portion on the surface of the conductive fine particles. It means extremely flat. The shape of such a plane portion is not particularly limited, and examples thereof include an arbitrary shape such as a circle, an ellipse, a polygon, and an indefinite shape.

The conductive fine particles having a shape having a substantially flat plane part on at least a part of the surface have excellent connection reliability because the plane part and the object to be connected are in surface contact and the contact area increases. It becomes. In particular, when the planar portion is formed at two or more locations on the surface of the conductive fine particles, and these planar portions are opposed to each other, two connected objects using the conductive fine particles of the present invention are used. When conductively connecting between the conductive particles, the conductive fine particles can be brought into surface contact with any object to be connected, and connection reliability can be further improved.

As the size of the flat portion, the area is preferably 50% or more of the area of a circle corresponding to the volume diameter of the conductive fine particles of the present invention. If it is less than 50%, the flat portion formed on the surface of the conductive fine particles is too small, and the flat portion may not come to the connected object side when conducting conductive connection with the connected object. Further, even when the flat portion comes to the connected object side, the contact area with the connected object may be reduced and the connection reliability may be inferior.

Moreover, it is preferable that the conductive fine particles have a longer diameter in a direction parallel to the planar portion than a diameter in a direction perpendicular to the planar portion. That is, it is preferable that the conductive fine particles of the present invention have a flat shape having the above-mentioned flat portion as a bottom surface and / or a top surface. Such flat conductive fine particles can ensure that the flat portion comes to the connected object side during conductive connection with the connected object, so that the contact between the two is a surface contact. And the connection reliability can be improved. Furthermore, when the conductive fine particles have a flat shape, the height can be lowered. For example, when a plurality of semiconductor packages are conductively connected with the flat conductive fine particles to be three-dimensionally stacked, The obtained three-dimensionally stacked semiconductor package can be reduced in height.

The method for producing the conductive fine particles of the present invention is not particularly limited, and examples thereof include a method of providing a conductive layer on the substrate particles by a conventionally known method such as electrolytic plating or non-electrolytic plating. The conductive layer is not particularly limited. For example, a metal such as gold, silver, platinum, copper, nickel, tin, lead, cobalt, zinc, bismuth, palladium, or an alloy thereof, tin-doped indium oxide (I
TO), metal oxides such as zinc oxide and tin oxide, and metal nitrides such as TiN. These may be used independently and 2 or more types may be used together.

Examples of an object to be connected by the conductive fine particles of the present invention include a substrate having an electrode or a conductive pattern formed on the surface, a fine electronic component such as a film, a semiconductor package, or a semiconductor chip, a switch, or a connector. Etc. include electronic parts.

According to the present invention, a method for producing fine particles having a uniform shape and size and capable of producing non-spherical fine particles easily and efficiently, and a method for producing the fine particles are provided. Fine particles produced can be provided.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Example 1)
A micromixer in which a groove-like channel 4 having a width of 100 μm and a depth of 100 μm is connected to a groove-like channel 1 having a width of 200 μm and a depth of 100 μm as shown in FIG. A syringe pump (not shown) is connected to the upstream side of 1 and the upstream side of the supply pipe 4;
A heating reaction tube (not shown) was connected to the downstream side of the flow channel 1, and a stirring tank was connected downstream of the heating reaction tube to produce a fine particle production apparatus for reacting the dispersed phase by heating.

A divinylbenzene solution to which a polymerization initiator and benzoyl peroxide are added is prepared as a liquid to be solidified by reaction, and 3% of poval (GL-03, manufactured by Nippon Gosei Kagaku Co., Ltd.) as a continuous phase
A solution was prepared.
Next, using a syringe pump, the continuous phase is fed to the flow path 1 at a flow rate of 30 mL / hr, while the divinylbenzene solution is fed to the supply pipe 4 at a flow rate of 0.1 mL / hr to open the opening. 3 was supplied into the flow path 1, and the dispersed phase was dispersed in the continuous phase.
By heating the dispersion to 80 ° C. in a heated reaction tube, the dispersed phase is polymerized to form fine particles,
Resin fine particles were produced by further polymerizing the dispersion containing the fine particles in a stirring vessel.

When the obtained resin fine particles were observed with an SEM, they were substantially spherical. Further, when the particle size of the resin fine particles was measured with a Coulter counter, the average particle size was 81 μm, and the CV value of the particle size was 1.8%.

(Example 2)
As a liquid solidified by reaction, 50 parts by weight of isoamyl acrylate, 50 parts by weight of trimethylolpropane triacrylate, and 2,2-diphenylethane 1-one (“Iluca 651” manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator A reaction solution in which 0.5 part by weight was added and dissolved was prepared, and 3% polyvinyl alcohol (“GL-03” manufactured by Nippon Synthetic Chemical Co., Ltd.) was prepared as a continuous phase.
Using the same apparatus as in Example 1, using a syringe pump, the continuous phase is sent to the flow path 1 at a flow rate of 30 mL / hr, while the reaction solution is supplied to the supply pipe 4 at a flow rate of 0.1 mL / hr. The solution was fed and supplied from the opening 3 into the flow path 1 to disperse the dispersed phase in the continuous phase.
Thereafter, the dispersion phase was polymerized by irradiating the dispersion with ultraviolet rays using an ultraviolet irradiation device to produce resin fine particles.

When the obtained resin fine particles were observed with an SEM, they were substantially spherical. Further, when the particle diameter of the resin fine particles was measured by a Coulter counter, the average particle diameter was 84 μm, and the CV value of the particle diameter was 2.2%.

(Example 3)
Using the reaction solution and the continuous phase prepared in Example 2, non-spherical resin fine particles were produced.
The cross-sectional shape in the direction perpendicular to the flow of the dispersion liquid in the flow channel in the fine particle production apparatus produced in Example 1 was substantially rectangular like the flow channel 30 shown in FIG. The short side of the cross section of this channel is 30 μm
It was.
Using a syringe pump, the continuous phase is sent to the flow path 1 at a flow rate of 72 mL / hr, while the reaction solution is sent to the supply pipe 4 at a flow rate of 0.1 mL / hr and the flow path is opened from the opening 3. The dispersed phase was dispersed in the continuous phase.
Thereafter, the dispersion phase was polymerized by irradiating the dispersion with ultraviolet rays using an ultraviolet irradiation device to produce resin fine particles.
When the obtained resin fine particles were observed with an SEM, all of the front shapes were elongated with a substantially rectangular shape, and the sizes were uniform.

Example 4
Using the reaction solution and the continuous phase prepared in Example 2, non-spherical resin fine particles were produced.
The cross-sectional shape in the direction perpendicular to the flow of the dispersion liquid in the flow channel in the fine particle production apparatus produced in Example 1 was circular as in the reaction section 40 shown in FIG. The diameter of the cross section of this photoreactive part is 30 μm.
m.
Using a syringe pump, the continuous phase is sent to the flow path 1 at a flow rate of 72 mL / hr, while the reaction solution is sent to the supply pipe 4 at a flow rate of 0.1 mL / hr and the flow path is opened from the opening 3. The dispersed phase was dispersed in the continuous phase.
Thereafter, the dispersion phase was polymerized by irradiating the dispersion with ultraviolet rays using an ultraviolet irradiation device to produce resin fine particles.
When the obtained resin fine particles were observed with an SEM, all of the front shapes were circular and elongated, and the sizes were uniform.

(Example 5)
Using the reaction solution and the continuous phase prepared in Example 2, non-spherical resin fine particles were produced.
The cross-sectional shape in the direction perpendicular to the flow of the dispersion liquid in the flow channel in the fine particle production apparatus produced in Example 1 was substantially triangular like the reaction unit 50 shown in FIG. The depth of the cross section of this photoreactive part is 5
It was set to 0 μm.
Using a syringe pump, the continuous phase is sent to the flow path 1 at a flow rate of 72 mL / hr, while the reaction solution is sent to the supply pipe 4 at a flow rate of 0.1 mL / hr and the flow path is opened from the opening 3. The dispersed phase was dispersed in the continuous phase.
Thereafter, the dispersion phase was polymerized by irradiating the dispersion with ultraviolet rays using an ultraviolet irradiation device to produce resin fine particles.
When the obtained resin fine particles were observed with an SEM, all of the front shapes were elongated with a substantially triangular shape, and the sizes were uniform.

(Example 6)
Using the resin fine particles obtained in Examples 1 to 5 as base particles, a conductive layer made of gold having a thickness of 1 μm was formed on the surface by electroless plating to obtain conductive fine particles.
When the obtained conductive fine particles were observed with an SEM, they all had the same shape as the base particles, and their sizes were extremely uniform.

According to the present invention, a method for producing fine particles having a uniform shape and size and capable of producing non-spherical fine particles easily and efficiently, and a method for producing the fine particles are provided. Fine particles produced can be provided.

It is sectional drawing which shows typically a mode that a dispersed phase is added to the flow path through which a medium flows. (A) is sectional drawing which shows the cross-sectional shape of the direction perpendicular | vertical to the flow of the dispersion liquid of a flow path, (b) is a front view of the microparticles | fine-particles manufactured, (c) is a top view of microparticles | fine-particles. is there. (A) is sectional drawing which shows the cross-sectional shape of the direction perpendicular | vertical to the flow of the dispersion liquid of a flow path, (b) is a front view of the microparticles | fine-particles manufactured, (c) is a top view of microparticles | fine-particles. is there. (A) is sectional drawing which shows the cross-sectional shape of the direction perpendicular | vertical to the flow of the dispersion liquid of a flow path, (b) is a front view of the microparticles | fine-particles manufactured, (c) is a top view of microparticles | fine-particles. is there. (A) is sectional drawing which shows the cross-sectional shape of the direction perpendicular | vertical to the flow of the dispersion liquid of a flow path, (b) is a front view of the microparticles | fine-particles manufactured, (c) is a top view of microparticles | fine-particles. is there.

Explanation of symbols

1, 20, 30, 40, 50 Channel 2 Continuous phase 3 Opening 4 Supply pipe 5 Liquid solidified by reaction 6 Dispersed phases 21, 31, 41, 51 Fine particles

Claims (10)

A method for producing fine particles, characterized in that a dispersed phase composed of a liquid that solidifies by a reaction is dispersed in a continuous phase that is substantially immiscible with the liquid, and the dispersed phase is solidified while flowing in the flow path. . 2. The method for producing fine particles according to claim 1, wherein the volume diameter of the dispersed phase composed of the liquid solidified by the reaction is larger than the area diameter of the cross section perpendicular to the flow direction of the dispersion liquid in the flow path. 2. The equivalent diameter of the flow path when solidifying the dispersed phase is 1 mm or less.
Or the manufacturing method of microparticles | fine-particles of 2. 4. The liquid that solidifies by reaction is a polymerizable monomer.
The manufacturing method of microparticles | fine-particles of description. A dispersed phase composed of a liquid that solidifies by reaction is dispersed by discharging the liquid from an opening connected to the flow path in a continuous phase that is substantially immiscible with the liquid flowing in the flow path. The method for producing fine particles according to claim 1, 2, 3 or 4. 6. Fine particles produced by the method for producing fine particles according to claim 1, 2, 3, 4 or 5. The fine particles according to claim 6, which are non-spherical. 8. The fine particles according to claim 7, wherein the shape of a cross section perpendicular to the longitudinal direction is a circle, an ellipse, a polygon or a star. The coefficient of variation of the volume diameter is 10% or less and is substantially similar.
Or the fine particles according to 8. Conductive fine particles comprising base particles composed of the fine particles according to claim 6, 7, 8, or 9, and a conductive layer formed on a surface of the base particles.

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