JP5875027B2 - Method for producing emulsified dispersion - Google Patents

Description

  The present invention relates to a method for producing an emulsified dispersion in which monodisperse particles are highly dispersed. More specifically, the present invention relates to a method for producing an emulsified dispersion in which monodisperse particles having an average particle diameter of 300 nm or less are highly dispersed using a microreactor.

  Polymer fine particle materials are used in various industrial fields, and their industrial value is remarkable. Due to its excellent physical properties, it is used in a wide range of fields such as optical materials, molding materials, printing materials, paints, adhesives, and various coating materials. As a method for producing polymer monodisperse fine particles, a top-down method in which monomer droplets are uniformly controlled and polymerized, and a bottom-up method in which polymer nuclei are formed in a reaction system and grown to form polymer particles. Can be broadly classified. A soap-free emulsion polymerization method is known as one of the methods for obtaining monodisperse fine particles by a bottom-up method. However, in order to stabilize the polymerization system or to control the particle size to 300 nm or less, a water-soluble polymer or the like is used. It was necessary to add protective colloids and surfactants.

  In recent years, a drastic review of the manufacturing method of chemical products has been urged due to soaring petroleum energy. In this context, interest in microreactors has increased. A microreactor is a device that performs a reaction in a narrow space, and it is not necessary to introduce a large-scale device, and it is expected to reduce investment costs and manufacturing costs. Further, it is known that the microreactor has a feature that the reaction surface temperature is easy because the reaction is performed in a narrow space, and the specific surface area per unit volume is large.

  Many methods of producing microparticles using a microreactor have been disclosed so far (see, for example, Patent Document 1), but the top-down method is used because the particle size of the target microparticles was as large as 1 μm or more. Was almost. In the continuous phase flowing through the microreactor, a dispersed phase containing a polymerizable monomer is discharged from a connected opening, and droplets composed of the dispersed phase dispersed are produced in the continuous phase. In the production method for obtaining monodisperse fine particles by polymerization, monodisperse fine particles having an average particle diameter of 50 nm to 500 nm by forming uniform monodisperse droplets by applying a uniform shearing force to the droplets from the outside Has been disclosed (see, for example, Patent Document 2), but it is necessary to add a surfactant and to apply a uniform shearing force. .

JP 2002-544309 A JP 2008-31419 A

  An object of the present invention is to provide an emulsified dispersion containing monodisperse fine polymer particles having a particle size of 300 nm or less, which was obtained only by adding a protective colloid such as a water-soluble polymer or a surfactant. An object of the present invention is to provide an emulsification containing monodisperse polymer fine particles having a particle size of 300 nm or less, which can be obtained only by adding a protective colloid such as a water-soluble polymer or a surfactant by using a microreactor. It is an object of the present invention to provide a production method capable of producing a dispersion without using a protective colloid such as a water-soluble polymer or a surfactant.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the reaction rate of the radical polymerizable monomer is 0.1 to 50% in the presence of the water-soluble radical initiator in the microtubular channel. After emulsion polymerization, the obtained emulsion polymerization solution is reacted in a reaction kettle equipped with a stirring blade to a reaction rate of 95% or more, thereby satisfying the following (1), (2), (3): It has been found that an emulsified dispersion of monodisperse fine particles can be obtained.
(1) An emulsified dispersion can be obtained in which the monodispersed fine particles contained have a particle size of 300 nm or less and a variation coefficient CV of particle size distribution of 15% or less.
(2) It is stable even when the solid content of the emulsified dispersion is 15% or more.
(3) The emulsified dispersion obtained by the production method is stable without containing a dispersion stabilizer or a surfactant.

  That is, in the present invention, in a microtubular channel having a micromixer and a heat transfer reaction vessel inside, a reaction rate of 0.1 to 50% is obtained in the presence of a water-soluble radical initiator. After the polymerization reaction until the reaction rate is 95% or higher using a reaction vessel equipped with a stirrer, the micromixer is water-soluble. It has a structure in which an aqueous medium containing a radical initiator and a radical polymerizable monomer can be mixed, and a structure in which the flow path diameter is reduced in the flow direction of the fluid after mixing. A feature of the present invention is to provide a method for producing an emulsified dispersion.

  In the present invention, as described above, an emulsified dispersion containing no dispersion stabilizer or surfactant can be provided, but a dispersion stabilizer or surfactant may be added depending on the intended use. Examples of the dispersion stabilizer include water-soluble polymer compounds that function as protective colloids. Examples of such water-soluble polymers include polyvinyl alcohol, polyethylene glycol, hydroxycellulose, carboxymethylcellulose, methylcellulose, polyacrylamide, polyacrylic acid, polymethacrylic acid and the like.

  These can be mixed with a fluid containing a water-soluble radical initiator and used at the time of emulsion polymerization in a microtubule, but when using a water-soluble polymer having a low heat resistance temperature, it is added at the time of subsequent batch reaction. You can also.

  According to the present invention, a monodisperse polymer having a particle size of 300 nm or less, which can be obtained only by adding a protective colloid such as a water-soluble polymer or a surfactant by using a combination of a microreactor and a batch reaction kettle. An emulsified dispersion containing fine particles can be produced and provided stably and with high production efficiency.

It is a disassembled perspective view which shows three types of plate structures of the chemical reaction device 1 used for this invention. It is a perspective view which shows the plate structure of the chemical reaction device 1 in FIG. It is a horizontal sectional view showing the whole schematic diagram composition including the joint part of chemical reaction device 1 used for the present invention. It is a disassembled perspective view which shows two types of plate structures of the chemical reaction device 2 used for the manufacturing method of this invention. It is a perspective view which shows the plate structure of the chemical reaction device 2 in FIG. It is a horizontal sectional view showing the whole schematic diagram composition including the joint part of chemical reaction device 2 used for the present invention. It is a perspective view which shows the plate structure of the chemical reaction device 3 used for this invention. It is a horizontal sectional view showing the whole schematic diagram composition including the joint part of chemical reaction device 3 used for the present invention. It is a disassembled perspective view which shows two types of plate structures of the chemical reaction device 1 in FIG. It is a schematic block diagram which shows typically the manufacturing apparatus used in the Example. These are monodisperse fine particles obtained in Example 2. These are monodisperse fine particles obtained in Example 2.

Next, details necessary for carrying out the present invention will be described in detail.
The emulsified dispersion containing the monodispersed fine particles of the present invention is prepared by emulsion-polymerizing a radical polymerizable monomer to a reaction rate of 0.1 to 50% in the presence of a water-soluble radical initiator in a microtubule, followed by stirring. It can manufacture by making it react to 95% or more of reaction rate in the reaction kettle provided with the blade | wing.

  There are no particular restrictions on the water-soluble radical initiator used in the present invention, and various types of water-soluble radical polymerization initiators conventionally used in radical polymerization can be used depending on the type of raw material radical polymerizable monomer. It can be selected and used accordingly. As such a water-soluble initiator, for example, water-soluble organic peroxides, water-soluble azo compounds, redox initiators, persulfates and the like are preferably used.

  Examples of the water-soluble organic peroxide include t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1 , 3,3-tetramethyl hydroperoxide and the like. Examples of water-soluble azo compounds include 2,2′-diamidinyl-2,2′-azopropane monohydrochloride, 2,2′-diamidinyl-2,2′-azobutane monohydrochloride, 2,2 Examples include '-diamidinyl-2,2'-azopentane monohydrochloride and 2,2'-azobis (2-methyl-4-diethylamino) butyronitrile hydrochloride.

  Furthermore, examples of the redox initiator include a combination of hydrogen peroxide and a reducing agent. In this case, as the reducing agent, divalent iron ions, copper ions, zinc ions, cobalt ions, vanadium ions and other metal ions, ascorbic acid, reducing sugars and the like are used. Examples of the persulfate include ammonium persulfate and potassium persulfate.

  One of these water-soluble radical polymerization initiators may be used alone, or two or more thereof may be used in combination.

  The radical polymerizable monomer used in the production method of the present invention is not particularly limited as long as it is a compound having a radical polymerizable unsaturated group. For example, methyl (meth) acrylate, ethyl (meta ) Acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) ) Acrylic unsaturated monomers of C1-C30 alkyl (meth) acrylates such as acrylates;

For example, alkyl styrene such as styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene and octyl styrene; fluorostyrene, chlorostyrene, bromostyrene, Halogenated styrene such as dibromostyrene and chloromethylstyrene; Styrenic unsaturated monomers such as nitrostyrene, acetylstyrene, methoxystyrene, α-methylstyrene, vinyltoluene;
Carboxylic acid group-containing unsaturated compounds such as (meth) acrylic acid, itaconic acid or its monoester, maleic acid or its monoester, fumaric acid or its monoester, itaconic acid or its monoester, crotonic acid, p-vinylbenzoic acid Monomers and salts thereof; 2- (meth) acrylamide-2-methylpropanesulfonic acid, vinylsulfonic acid, styrenesulfonic acid, (meth) allylsulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, sulfonic acid group-containing unsaturated monomers such as α-methylstyrene sulfonic acid and salts thereof;

Dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, vinylpyrrolidone, N-methylvinylpyridium chloride, (meth) allyltriethylammonium chloride, 2-hydroxy-3- (meth) acryloyloxypropyltrimethylammonium chloride, etc. A tertiary or quaternary amino group-containing unsaturated monomer; a hydroxyl-containing unsaturated monomer such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, or polyethylene glycol mono (meth) acrylate; ) Amide-containing unsaturated monomers such as acrylamide, N-hydroxyalkyl (meth) acrylamide, N-alkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide, vinyl lactams

Unsaturated dibasic acid diesters such as maleic acid, fumaric acid, itaconic acid, aromatic unsaturated monomers such as styrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, chloromethylstyrene, vinyltoluene Nitrile unsaturated monomers such as acrylonitrile and methacrylonitrile; conjugated diolefin unsaturated monomers such as butadiene and isoprene;
Multifunctional unsaturation such as divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, allyl methacrylate, diallyl phthalate, trimethylolpropane triacrylate, glyceryl diallyl ether, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate Monomer;

Vinyl unsaturated monomers such as ethylene, propylene and isobutylene;
Vinyl ester unsaturated monomers such as vinyl acetate, vinyl propionate, octyl vinyl ester, Veova 9, Veova 10, Veova 11 [Beova: Shell Chemical Company, Ltd.]; ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, cyclohexyl Vinyl ether unsaturated monomers such as vinyl ether; allyl ether unsaturated monomers such as ethyl allyl ether;

Halogen-free products such as vinyl chloride, vinyl bromide, vinylidene chloride, vinylidene fluoride, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, pentafluoropropylene, perfluoro (propyl vinyl ether), perfluoroalkyl acrylate, and fluoromethacrylate Saturated monomers, etc .;
Epoxy group-containing unsaturated monomers such as glycidyl acrylate and glycidyl methacrylate; vinyl silanes such as vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, and γ-methacryloxypropyltrimethoxysilane Unsaturated monomers;

Examples thereof include carbonyl group-containing unsaturated monomers such as acrolein, diacetone acrylamide, vinyl methyl ketone, vinyl butyl ketone, diacetone acrylate, acetonitrile acrylate, acetoacetoxyethyl (meth) acrylate, vinyl acetophenone and vinyl benzophenone.

  The emulsified dispersion containing the monodispersed fine particles of the present invention is obtained by emulsion-polymerizing a radical polymerizable monomer to a reaction rate of 0.1 to 50% in the presence of a water-soluble initiator in a microtubule, and then stirring blades. It can manufacture by making it react to 95% or more of reaction rates.

  The emulsified dispersion containing the monodispersed fine particles of the present invention preferably has a residual monomer amount of 500 ppm or less.

  More specifically, the emulsified dispersion containing the monodispersed fine particles of the present invention uses a micromixer having a microtubular channel formed therein and a reaction vessel having a microtubular channel formed therein, and uses a water-soluble radical. In the presence of an initiator, after the emulsion polymerization to a reaction rate of 0.1 to 50% of the radical polymerizable monomer, it can be produced by reacting to a reaction rate of 95% or more in a reaction kettle equipped with a stirring blade. it can.

  More specifically, the emulsified dispersion containing monodisperse fine particles of the present invention uses a micromixer having a microtubular channel formed therein and a reaction vessel having a microtubular channel formed therein, By mixing a fluid of an aqueous medium containing a water-soluble radical initiator and a medium containing a radical polymerizable monomer with a micromixer in which a microtubular channel is formed, oil droplets of the radical polymerizable monomer are After being formed in an aqueous medium containing a water-soluble radical initiator, the radical polymerizable monomer partially dissolved in the aqueous medium is decomposed by the decomposition of the water-soluble radical initiator in a reaction vessel in which a microtubular channel is formed. The polymer begins to polymerize, and due to the increase in hydrophobicity due to the increase in chain length, precipitation aggregation occurs and fine particle nuclei are formed. From the droplets of radically polymerizable monomers finely dispersed in the aqueous phase, the particle nucleus surface Radically polymerizable Polymerization proceeds by supplying the monomer, and after emulsion polymerization to a reaction rate of 0.1 to 50% of the radical polymerizable monomer, the reaction rate is reacted to 95% or more in a reaction kettle equipped with a stirring blade. Can be manufactured.

  By using a micromixer, the mixing of the aqueous medium containing the water-soluble radical initiator and the medium containing the radical polymerizable monomer is a mixture of small segments, so the contact area becomes large, so the energy is small. However, mixing is promoted, and the radical polymerizable monomer can be finely dispersed in an aqueous medium containing a water-soluble radical initiator even at a relatively low flow rate. Fine dispersion is preferable because monodisperse particle nuclei grow by supplying radically polymerizable monomers smoothly and uniformly from the oil droplets of radically polymerizable monomers to the surface of the particle nuclei.

  In general, polymer particles obtained by soap-free emulsion polymerization as described above are stabilized by repulsion due to the charge of the radical initiator segment and adsorption of the oligo soap produced as a by-product to the particle surface. Generation of and stabilization of fine particle nuclei is promoted by decomposing more radical initiators in a reaction vessel in which uniform oil droplets are formed and microtubular channels are formed inside. Nucleation and growth of monodisperse fine particles having a smaller particle diameter obtained in (1) can be realized.

  A commercially available micromixer can be used as the micromixer having a microtubular channel formed therein. For example, a microreactor having an interdigital channel structure, an institute, a fool, a microtechnique, a mainz ( IMM) single mixer and caterpillar mixer; Microglass microglass reactor; CPC Systems Cytos; Yamatake YM-1, YM-2 mixer; Shimadzu GLC mixing tee and tee (T-shaped connector) ); IMT chip reactor manufactured by Micro Chemical Engineering Co., Ltd .; Toray Engineering developed product, Micro High Mixer, etc., and any of them can be used in the present invention.

  Furthermore, as a preferred form of the micromixer system, an aqueous medium containing a water-soluble radical initiator and a radical polymerizable monomer are circulated in separate flow paths and mixed at the outlets of both the flow paths. After mixing using a micromixer, a micromixer that further promotes mixing by supplying and flowing to a flow path whose flow path cross-sectional area is reduced in the flow direction is preferable. Mixing can be further promoted by a turbulent flow effect caused by further contracting the flow path.

  After mixing using a micromixer that mixes at the outlets of both the flow paths, mixing is promoted by supplying the flow to a flow path whose flow path cross-sectional area is reduced in the flow direction. By using a micromixer, it becomes possible to promote dispersion of a radical polymerizable monomer in an aqueous medium containing a water-soluble radical initiator.

  After mixing using a micromixer that mixes at the outlets of both the flow paths, mixing is promoted by supplying the flow to the flow path whose flow path cross-sectional area is reduced in the flow direction. The micromixer microtubular flow path may be a combination of at least two members and a space formed between the members is used as the flow path. It may be used as a road.

  For example, the chemical reaction device 1 is exemplified as a preferable form of the micromixer that is mixed at the junction provided at the outlet of the flow path used in the present invention. Moreover, the device 2 for chemical reaction is illustrated as a micromixer which accelerates | stimulates mixing by the flow path by which the flow-path cross-sectional area was reduced in the flow direction.

Hereinafter, the chemical reaction device 1 and the chemical reaction device 2 provided with a flow channel in a preferable form used in the present invention will be specifically described. FIG. 1 shows a plate in which a microtubular channel through which a fluid containing a radical polymerizable monomer passes, a plate in which a microtubular channel through which a fluid containing a water-soluble radical initiator passes, and heat exchange are performed. It is a schematic structural example of the reaction apparatus formed by laminating | stacking the plate which installed the flow path through which a fluid flows. FIG. 2 shows a chemical reaction device 1 formed by laminating a plate on which microtubular channels for flowing the mixed liquid in the device of FIG. 1 are arranged and a plate on which a channel for flowing a fluid for heat exchange is installed. This is a schematic configuration example.
The chemical reaction device 1 includes, for example, a plurality of first plates (5 in FIG. 1) and second plates (8 in FIG. 1) alternately formed in the same rectangular plate shape in FIG. Configured. Further, as required, a third plate (3 in FIG. 1) is laminated as shown in FIG. Each one first plate is provided with a flow path through which a fluid containing a radical polymerizable monomer passes. The second plate is provided with a flow path (hereinafter referred to as a reaction flow path) through which a fluid containing a water-soluble radical initiator passes (hereinafter, the plate provided with the reaction flow path is referred to as a process plate). The third plate is provided with a flow channel for temperature control fluid (hereinafter referred to as a temperature control channel) (hereinafter, the plate provided with the temperature control channel is referred to as a temperature control plate).

  As shown in FIG. 3, these supply ports and discharge ports are dispersed and arranged in each region of the end faces 15b, 15c and side surfaces 15d, 15e of the chemical reaction device 1, and a water-soluble radical initiator is placed in these regions. Fluid containing δ (in FIG. 2 indicates a fluid flow of a fluid containing a water-soluble radical initiator), fluid containing a radical polymerizable monomer (ε in FIG. 2 is a fluid flow of a fluid containing a radical polymerizable monomer) , And a joint portion 32 composed of a connector 30 and a joint portion 31 for flowing a temperature control fluid (γ in FIG. 2 indicates the flow of the temperature control fluid). Further, the outlet mixing is achieved by the fluid containing the radical polymerizable monomer and the fluid containing the water-soluble radical initiator joining in the space 33 formed by the end face 15c of the chemical reaction device 1 and the connector 30. .

Via these joints, a fluid containing a radical polymerizable monomer and a fluid containing a water-soluble radical initiator are supplied from the end face 15b, discharged to the end face 15c, and a temperature-controlled fluid is supplied from the side face 15d. It is discharged to the side surface 15e.
The planar view shape of the device for chemical reaction 1 is not limited to the rectangular shape as shown in the figure, and may be a square shape or a rectangular shape with the side surfaces 15d and 15e longer than between the end surfaces 15b and 15c. Therefore, in accordance with the illustrated shape, the direction from the end face 15b to the end face 15c is referred to as the longitudinal direction of the process plate and the temperature control plate of the chemical reaction device 1, and the direction from the side face 15d to the side face 15e is referred to as the chemical reaction device. This is referred to as the short direction of the process plate 1 and the temperature control plate.
The chemical reaction device 2 includes, for example, a fourth plate (14 in FIG. 4) having the same rectangular plate shape in FIG. 4, and a temperature control plate (3 in FIG. 4) in FIG. As shown, they are stacked. Each one fourth plate is provided with a flow path through which the fluid mixed in the chemical reaction device 1 passes.
Then, as shown in FIG. 6, these supply ports and discharge ports are distributed and arranged in each region of the end surfaces 16b, 16c, and side surfaces 16d, 16e of the chemical reaction device 2, and in these regions, radically polymerizable single molecules are disposed. For flowing a fluid containing a mer and a fluid containing a water-soluble radical initiator (α in FIG. 5 indicates a liquid fluid) and, if necessary, a temperature adjusting fluid (γ indicates a temperature adjusting fluid in FIG. 5) A joint part 32 composed of a connector 30 and a joint part 31 is connected to each other.

Through these joint portions, a fluid containing a fluid containing a radical polymerizable monomer and a fluid containing a water-soluble radical initiator is supplied from the end face 16b, discharged to the end face 16c, and the temperature control fluid is discharged from the side face 16e. It is supplied and discharged to the side surface 16d.
The shape of the chemical reaction device 2 in plan view is not limited to the rectangular shape shown in the figure, and may be a square shape or a rectangular shape with the side surfaces 16d and 16e longer than between the end surfaces 16b and 16c. Therefore, in accordance with the illustrated shape, the direction from the end face 16b to the end face 16c is referred to as the longitudinal direction of the process plate and the temperature control plate of the chemical reaction device 2, and the direction from the side face 16d to the side face 16e is referred to as the chemical reaction device. The short direction of the process plate 2 and the temperature control plate will be referred to.

As shown in FIG. 1, the temperature control plate is provided with a temperature control flow path 6 having a concave groove shape on one surface 3 a at a predetermined interval. The cross-sectional area of the temperature control channel 6 is not particularly limited as long as heat can be transferred to the reaction channel, but is approximately in the range of 1 × 10 −2 to 2.5 × 102 (mm ² ). . More preferably, it is 0.32-4.0 (mm < ² >). The number of the temperature control flow paths 6 can adopt an appropriate number in consideration of heat exchange efficiency, and is not particularly limited, but is, for example, 1 to 1000, preferably 10 to 100 per plate. It is.

As shown in FIGS. 1 and 4, the temperature control channel 6 flows in a plurality of main channels 6 a arranged along the longitudinal direction of the temperature control plate, and upstream and downstream ends of the main channel 6 a, respectively. You may provide the supply side flow path 6b and the discharge side flow path 6c which are arrange | positioned substantially orthogonally to the path | route 20, and are connected to each main flow path 6a. In FIGS. 1 and 4, the supply-side flow path 6b and the discharge-side flow path 6c are bent at right angles twice and open to the outside from the side surfaces 3d and 3e of the temperature control plate. As for the number of each temperature control channel 6, only the main channel 6 a portion of the temperature control channel 6 is arranged, and the supply side channel 6 b and the discharge side channel 6 c are each composed of one. .
In the emulsified dispersion according to the present invention, a radical polymerizable monomer is finely dispersed in an aqueous medium containing a water-soluble radical initiator by the micromixer, and then a reaction vessel in which a microtubular channel is formed. The emulsion can be produced by emulsion polymerization to a reaction rate of 0.1 to 50% of the radical polymerizable monomer and then reacting to a reaction rate of 95% or more in a reaction kettle equipped with a stirring blade.

The flow path used in the production method of the present invention can be any micro-tubular flow path, and other requirements are not particularly limited. A simple pipe or pipe shape may be used as the reaction channel. In addition, a space formed between the members can be used as a reaction channel by combining at least two members.
The emulsified dispersion according to the present invention promotes the generation and stabilization of fine particle nuclei by emulsion polymerization of a radical polymerizable monomer in a temperature range of 70 ° C. to 200 ° C. Nucleation and growth of smaller monodispersed fine particles obtained by batch reaction can be realized.

  Usually, when preparing an emulsified dispersion containing polymer monodispersed fine particles only in a batch reaction kettle, the reaction temperature is set to 50 ° C to 90 ° C. This is set together with the 10-hour half-life temperature of persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate that are usually used in soap-free emulsion polymerization. This may lead to runaway of the water, and the boiling point of water may exceed 100 ° C. Therefore, it is very dangerous except for batch reactors with special measures such as pressure resistance setting. On the other hand, in the microreactor, it is possible to increase the temperature and pressure safely and easily by providing a pressure adjusting valve at the outlet of the flow path. For this reason, no problem occurs even when the temperature of the aqueous medium exceeds 100 ° C.

In general, the radical decomposition rate constant of the radical polymerization initiator can be obtained by the following formula.
k = A × EXP (−E / RT)
k: radical decomposition rate constant (h ⁻¹ ) of polymerization initiator, A: frequency factor (h ⁻¹ ),
E: activation energy (J / mol), R: gas constant (= 8.314 J / mol · K)
T: Absolute temperature (K)

As is apparent from the above calculation formula, radical decomposition increases exponentially with increasing temperature. In a reaction vessel having a microtubular channel formed therein, the fluid temperature is increased to a range of 70 ° C. to 200 ° C., thereby rapidly increasing the amount of initiator slices that contribute to the nucleation and stability of fine particles. be able to. Compared to ordinary batch reaction kettles, it is safe, convenient, efficient, monodisperse fine particles with extremely high dispersion stability and small particle size without the addition of protective colloids such as water-soluble polymers and surfactants. Can also be generated.
The reaction temperature is preferably 70 ° C to 200 ° C, more preferably 90 ° C to 180 ° C, and most preferably 110 ° C to 160 ° C. When the temperature is 70 ° C. or lower, there is no difference from the batch, and when the temperature is 200 ° C. or higher, the initiator is decomposed too quickly, so there is almost no difference in effect. The above-mentioned effect can be most obtained at 70 ° C. to 200 ° C.

Further, in the present invention, the water-soluble radical polymerization is initiated by continuously controlling the Reynolds number in the reaction vessel of the fluid containing the water-soluble radical initiator and the radical polymerizable monomer at 0.25 to 300. Since the mixing property of the fluid containing the agent and the radical polymerizable monomer is further enhanced by the turbulent flow effect, it can be manufactured more efficiently.
Here, by controlling the movement of the fluid in the flow path at a value larger than the Reynolds number 0.25, the mixing property of the fluid containing the water-soluble radical polymerization initiator and the radical polymerizable monomer is not significantly reduced, As a result, the particle nuclei are preferably grown uniformly and problems such as blockage of the flow path due to aggregation can be avoided. In addition, it is difficult to control the Reynolds number to 300 or more, and if the Reynolds number is too large, the collision frequency between particles increases and the repetition frequency of particle coalescence and separation increases. May spread.

  The Reynolds number as used in the present invention is calculated according to the following formula (1).

Reynolds number = (D × u × ρ) / μ (1)
Here, D (inner diameter of the flow path), u (average flow velocity), ρ (fluid density), and μ (fluid viscosity).

The ratio of the fluid containing the water-soluble radical initiator and the fluid containing the radical polymerizable monomer in the microtubule depends on the polymer fine particle concentration of the target emulsified dispersion. In order to promote the generation and stabilization of fine particle nuclei in the flow path, it is possible to obtain an emulsified dispersion having a smaller particle size and a higher solid content concentration than in a normal batch reaction. The ratio of the fluid containing the radical polymerizable monomer in the fluid containing the water-soluble radical initiator in the microtubule is usually 5-60%, preferably 10-50%, more preferably 15-40%. is there. If it exceeds 60%, there is a high possibility that the particles will aggregate and settle even by the method of the present invention. It becomes possible to obtain a stable emulsified dispersion by setting the ratio of the fluid containing the radical polymerizable monomer in the fluid containing the water-soluble radical initiator to 5-60%.
As the reaction apparatus used in the production method of the present invention, a reaction apparatus in which a flow path is installed in a heat transfer reaction vessel is preferable. Since the flow path is a microtubule, heating can be quickly controlled. preferable. The microtubular channel is preferably of a size that can adjust the time to reach the polymerization reaction temperature in a short time and is sufficiently large to prevent clogging, and has a fluid cross-sectional area of 0.1 to 4 A flow path having a gap size of 0.0 mm ² is preferable because it is easy to adjust the time to reach the polymerization reaction temperature in a short time and is sufficiently large to prevent clogging. In the present invention, “cross section” means a cross section perpendicular to the flow direction in the flow path, and “cross section” means the cross section.

  The cross-sectional shape of the channel is a square, a rectangle including a rectangle, a polygon including a trapezoid, a parallelogram, a triangle, a pentagon, etc. (a shape with rounded corners, a high aspect ratio, ie including a slit shape) It may be a star shape, a semicircle, a circle including an ellipse, or the like. The cross-sectional shape of the channel need not be constant.

  The method of forming the reaction channel is not particularly limited, but generally, the member (X) having a groove on the surface thereof is laminated, bonded, or the like on the surface having the groove. It is fixed and formed as a space between the member (X) and the member (Y).

  The channel may further be provided with a heat exchange function. In that case, for example, a groove for flowing the temperature adjusting fluid is provided on the surface of the member (X), and another member is bonded or laminated on the surface provided with the groove for flowing the temperature adjusting fluid. What is necessary is just to fix. In general, a member (X) having a groove on the surface and a member (Y) provided with a groove for flowing a temperature-controlled fluid include a surface provided with a groove, and a surface provided with a groove of another member. A flow path may be formed by fixing the opposite surface, and a plurality of these members (X) and members (Y) may be fixed alternately.

  At this time, the groove formed on the member surface may be formed as a so-called groove lower than the peripheral portion thereof, or may be formed between the walls standing on the member surface. The method of providing the groove on the surface of the member is arbitrary, and for example, methods such as injection molding, solvent casting method, melt replica method, cutting, etching, photolithography (including energy beam lithography), and laser ablation can be used.

  The layout of the flow paths in the member may be in the form of a straight line, a branch, a comb, a curve, a spiral, a zigzag, or any other arrangement according to the purpose of use.

The outer shape of the member need not be particularly limited, and can take a shape according to the purpose of use. The shape of the member may be, for example, a plate shape, a sheet shape (including a film shape, a ribbon shape, etc.), a coating film shape, a rod shape, a tube shape, and other complicated shapes. External dimensions such as thickness are preferably constant. The material of the member is arbitrary, and may be, for example, a polymer, glass, ceramic, metal, semiconductor, or the like.
The reaction vessel having a microtubular channel formed therein for obtaining the emulsified dispersion of the present invention has a structure in which a heat conductive plate-like structure having a plurality of grooves formed on the surface is laminated. An apparatus can be used.
The reaction vessel having a microtubular channel formed therein has a heat exchange function and a fluid cross-sectional area flowing in a liquid-tight manner in the microtubular channel is 0.1 to 4.0 mm ^2. Those having a microtubular channel having a void size are preferable, and other requirements are not particularly limited. Examples of such a reaction container include a reaction container in which the channel (hereinafter, simply referred to as “microchannel”) is provided in a member used as a chemical reaction device.
Hereinafter, the reaction vessel having a microtubular channel formed therein will be specifically described. FIG. 7 shows a reaction vessel in which a plate provided with a microtubular flow channel for flowing a mixed solution and a plate provided with a flow channel for flowing a fluid that exchanges heat between the mixed solution are alternately stacked. A schematic configuration example of a reaction vessel (chemical reaction device 3) having a microtubular channel having a void size in which a fluid cross-sectional area flowing in a liquid-tight manner in the microtubular channel is 0.1 to 4.0 mm ² It is.

  The chemical reaction device 3 includes, for example, a first plate (process plate) (2 in FIG. 7) and a second plate (temperature control plate) (in FIG. 7) having the same rectangular plate shape in FIG. And 3) are alternately stacked. Each one first plate is provided with a reaction channel. The second plate is provided with a temperature control channel.

  As shown in FIG. 8, these supply ports and discharge ports are dispersed and arranged in each region of the end surfaces 1b, 1c, side surfaces 1d, 1e of the chemical reaction device 3, and in these regions, radical polymerizable monomers are arranged. The joint part 32 including the connector 30 and the joint part 31 for flowing the fluid containing the water-soluble radical initiator and the temperature control fluid is connected to each other.

  Via these joint portions, a fluid containing a radical polymerizable monomer and a water-soluble radical initiator is supplied from the end surface 1b and discharged to the end surface 1c, and a temperature-controlled fluid is supplied from the side surface 1e to the side surface 1d. It is supposed to be discharged.

  The shape of the chemical reaction device 3 in plan view is not limited to the rectangular shape shown in the figure, and may be a square shape or a rectangular shape with the side surfaces 1d and 1e longer than between the end surfaces 1b and 1c. Therefore, in accordance with the illustrated shape, the direction from the end surface 1b to the end surface 1c is referred to as the longitudinal direction of the process plate and temperature control plate of the chemical reaction device 1, and the direction from the side surface 1d to the side surface 1e is referred to as the chemical reaction device. 3 is referred to as the short direction of the process plate and the temperature control plate.

  As shown in FIG. 9, the process plate is formed by extending a flow path 4 having a concave groove shape in one surface 2a in the longitudinal direction of the process plate and arranging a plurality of the process plates at a predetermined interval p0 in the short direction. It is. Let L be the length of the flow path 4. The cross-sectional shape is a width w0 and a depth d0.

  The cross-sectional shape of the flow path 4 can be appropriately set according to the type of fluid containing the radical polymerizable monomer and the water-soluble radical initiator, the flow rate, and the flow path length L. In order to ensure uniformity, the width w0 and the depth d0 are set in the range of 0.1 to 500 [mm] and 0.1 to 5 [mm], respectively. In addition, description of a width | variety and a depth is a case where a drawing is referred, Comprising: This value can be interpreted suitably so that it may become a wide value with respect to a heat transfer surface. Although it does not specifically limit, For example, 1-1000 pieces per plate, Preferably it is 10-100 pieces.

  The fluid containing the radical polymerizable monomer and the water-soluble radical initiator is caused to flow into each flow path 4 and is supplied from one end face 2b side as indicated by an arrow in FIGS. It is discharged to the end face 2c side.

  The plurality of process plates and temperature control plates are stacked by alternately stacking process plates and temperature control plates in the same direction, and are fixed to each other and stacked.

  Therefore, in the form of the chemical reaction device 3, each flow path 4 and the temperature control flow path 6 are covered with a lower surface of a plate on which the opening surface of the groove is laminated, and a tunnel shape having a rectangular cross section with both ends opened. It is said.

  Each process plate and temperature control plate can be made of an appropriate metal material. For example, a flow path 4 and a temperature control path 6 are formed by etching a stainless steel plate, and the flow path surface is changed. It can be manufactured by electrolytic polishing finish.

  As an apparatus having a chemical reaction device provided with a flow path used in the manufacturing method of the present invention, for example, a manufacturing apparatus shown in FIG. 10 can be exemplified.

  In FIG. 10, the fluid containing the radical polymerizable monomer is composed of the outlet of the tank 62 (first tank) into which the fluid (61) containing the radical polymerizable monomer and the inlet of the plunger pump 65 are placed. An outlet of a tank 64 (first tank) for containing a fluid containing a water-soluble radical initiator and an inlet of a plunger pump 66 are connected to each other through a piping that passes through the water-soluble radical initiator. It is connected via a pipe through which the fluid (63) it contains passes. Pipes through which a fluid containing a radical polymerizable monomer or a fluid containing a water-soluble radical initiator passes from the outlet of the plunger pump 65 and the outlet of the plunger pump 66 through the plunger pump 65 or the plunger pump 66, respectively. These pipes are connected to the inlet of the micromixer 67 which mixes at the junction provided at the outlet of the flow path exemplified as the chemical device 1 shown in FIGS. 1, 2, and 3. It is connected.

  In this micromixer 67, a fluid (61) containing a radical polymerizable monomer and a fluid (63) containing a water-soluble radical initiator are mixed, and the chemical device 2 shown in FIGS. The fluid is mixed with the radical polymerizable monomer and the water-soluble radical initiator by being guided to the micromixer 73 that promotes mixing by the flow path whose flow path cross-sectional area is reduced in the illustrated flow direction. . This fluid moves through the pipe connected to the outlet of the micromixer 73 to the inlet 1b of the reaction vessel 40 exemplified as the chemical device 3 shown in FIGS. A temperature control device 68 is connected to the reaction vessel 40. The radical polymerizable monomer is finely dispersed in the aqueous medium containing the water-soluble radical initiator by moving through the micro flow path in the reaction vessel 40 and dissolved in the aqueous medium by the decomposition of the water-soluble radical initiator. The core of fine particles is formed by polymerization precipitation of the radically polymerizable monomer, and the radically polymerizable monomer is supplied to the surface of the particle core from the oil droplets of the radically polymerizable monomer finely dispersed in the aqueous phase. Polymerization proceeds, moves through the micro flow path in the reaction vessel 40, and reaches the outlet 1 c of the reaction vessel 40. Then, it moves to the inflow port of the cooling heat exchanger 70 through the pipe connected to the outflow port. In the reaction container 40 of the manufacturing apparatus of FIG. 10, the residence time can be controlled by connecting several chemical devices 3 described in FIGS. 7, 8 and 9 as a part of the reaction container through the flow path. .

  As for the residence time, the reaction rate at the outlet of the reaction vessel is suitably 0.1 to 50%, more preferably 0.5 to 30%, depending on the reaction temperature and flow rate. When the reaction rate is lower than 0.1%, the monodispersity of the particles cannot be obtained, and in order to react more than 50%, it is necessary to lengthen the flow path. There is a risk of clogging the flow path due to adhesion of the polymer component. By controlling the content to 0.1 to 50%, an emulsified dispersion containing fine particles with high monodispersibility can be obtained, and the flow path can be stably blocked without clogging.

  Such a residence time depends on the reaction temperature, flow rate, and the type of water-soluble radical initiator used, but when using a persulfate as the water-soluble radical initiator, 0.1 to 30 minutes, preferably Is 0.2 to 20 minutes, more preferably 0.5 to 15 minutes.

  The emulsified dispersion obtained from the outlet of the flow path can be polymerized to a reaction rate of 95% or more in an ordinary batch reaction kettle equipped with a stirrer by adding a water-soluble radical initiator as necessary.

  As the water-soluble radical initiator to be added, the aforementioned water-soluble organic peroxides, water-soluble azo compounds, redox initiators, persulfates and the like are preferably used.

  At this time, a radical polymerizable monomer may be added for the purpose of introducing a functional group on the particle surface. The radical polymerizable monomer described above can be added as the radical polymerizable monomer to be added.

  There is no particular limitation on the reaction temperature, but when using a persulfate as a water-soluble radical initiator and a batch reaction kettle used under normal atmospheric pressure, 50-90 ° C., more preferably 60 ° C.-85 ° C is preferred.

  Although the reaction time depends on the temperature, it is usually 0.5 hours to 10 hours. In the present invention, as described above, in the microtubular channel, the radical polymerizable monomer is emulsion-polymerized to a reaction rate of 0.1 to 50% in the presence of a water-soluble radical initiator, and then provided with a stirring blade. By reacting to a reaction rate of 95% or more in the reaction kettle, the particle size of the monodispersed fine particles contained is 300 nm or less, the coefficient of variation CV of the particle size distribution is 15% or less, and the solid content of the monodispersed fine particles is An emulsified dispersion containing 15% or more and having a residual monomer amount of 500 ppm or less and containing no dispersion stabilizer or surfactant can be obtained.

  In general, polymer particles obtained by soap-free emulsion polymerization as described above are stabilized by repulsion due to the charge of radical initiator segments and adsorption of by-product oligosoap to the particle surface. In the reaction, in order to obtain monodisperse fine particles of 300 nm or less, it was necessary to carry out under extremely dilute conditions, or the system became unstable. In order to promote the generation and stabilization, an emulsified dispersion containing a dispersion stabilizer or a surfactant having a smaller particle size and a higher solid content than a normal batch reaction can be obtained.

Hereinafter, the present invention will be described in more detail by way of examples. In the examples,% and weight are based on weight unless otherwise specified.

<Micromixer used in this example>
In this embodiment, the process plates 5 and 8 having the structure shown in FIG. 1 were used as the micromixer as a micromixer for mixing at the junction provided at the outlet of the flow path. Further, as a micromixer that promotes mixing by a flow path whose flow path cross-sectional area is reduced in the flow direction, a process plate 14 having a structure shown in FIG. 4 was used as the micromixer. The structure of the micromixer includes a chemical reaction device in which the temperature control plate 3 is stacked on the top and bottom of the micromixer laminate in which the plate 5 is stacked on the plate 8, and a chemical in which the temperature control plate 3 is stacked on the top and bottom of the plate 14 A structure in which a reaction device was connected in series was used. Specifically, an aqueous fluid in which a water-soluble radical initiator was dissolved was introduced into the flow channel 20 of the plate 5 into the flow channel 21 of the radical polymerizable monomer plate 8, and the respective fluids were united at the plate outlet. Thereafter, the radical polymerizable monomer was further finely dispersed in an aqueous fluid in which a water-soluble radical initiator was dissolved by passing through the flow path 22 of the plate 14. The process plates 5, 8, and 14 and the temperature control plate 3 are made of SUS304, and the plate thicknesses of the plates 5 and 14 are 0.4 mm and the plate 8 is 1 mm. The cross-sectional dimension of the reaction channel 21 is 1.0 mm wide × 0.5 mm deep, the cross-sectional dimension of the temperature control channel 6 is 1.2 mm wide × 0.5 mm deep, and the cross-sectional dimension of the reaction channel 20 is 6 mm wide × The depth is 0.2 mm, and the cross-sectional dimension of the reaction channel 22 is 4 mm wide × 0.2 mm deep at the wide portion and 0.2 mm wide × 0.2 mm deep at the contracted portion.

<Reaction container device used in this example>
In this example, a reaction vessel device having the structure shown in FIG. 7 was used. As a structure, the process plate 2 and the temperature control plate 3 are alternately laminated. A flow path 4 is formed in the process plate, and a temperature control flow path 6 is formed in the temperature control plate.
The reaction vessel device is formed by alternately laminating three temperature control plates with five temperature control channels 6 formed by etching, as well as two process plates with five reaction channels 4 formed by dry etching. Yes. The material of the process plate 2 and the temperature control plate 3 is SUS304, and the plate thickness is 1 mm. The cross-sectional dimensions of the reaction channel 4 and the temperature control channel 6 are both width 1.2 mm × depth 0.5 mm.

<Measurement method of residual monomer amount>
Measurement was performed using a GCMS device GCMS-QP5050ACI manufactured by Shimadzu Corporation. The polymerization solution was dissolved in acetone and measured.

<Measuring method of particle size and monodispersity>
Measurement was performed using a Nikkiso Co., Ltd. Microtrac particle size distribution analyzer UPA-ST150. The emulsified dispersion was diluted about 100 times and placed in a cell for measurement. The coefficient of variation (CV) of the particle size distribution of the monodisperse fine particles according to the present invention is defined by the following equation in the average particle size (d) and standard deviation (SD) of the particle size distribution obtained by measurement. For example, it is obtained by the measurement of the particle size distribution meter.
CV (%) = 100 × SD / d

<Measurement method of solid content of emulsion dispersion polymer>
1 g of the emulsified dispersion was weighed in a metal petri dish with a precision balance, diluted with 1 g of ion-exchanged water, and then dried for 2 hours in a dryer set at 110 ° C. The polymer solid content in the emulsified dispersion was measured from the resin solid content remaining in the petri dish after drying and the amount of the emulsified dispersion initially weighed.

Example 1
Two syringe pumps and a 2.17 mm tube were connected to the outlet of each syringe via a pressure gauge, a safety valve, a filter, and a check valve. Each tube was connected to the micromixer shown in FIGS. 1 and 4, and further connected to a 2.17 mm × 12 m tube. The 2.17 mm × 12 m tube was immersed in a thermostatic bath so that it could be heated. Further, a 2.17 mm × 2 m tube was connected, and this was immersed in water so that it could be cooled. Finally, a back pressure valve was connected so that the discharged reaction mixture could be received in a container.

  In one syringe, an aqueous solution in which 0.075 g of sodium persulfate was dissolved in 100 g of ion-exchanged water was prepared and charged. The other syringe was charged with methyl methacrylate (MMA). A reaction tube having an inner diameter of 2.17 mm with a sodium persulfate aqueous solution at a flow rate of 16 g / min and an MMA solution at a flow rate of 4 g / min so that the reaction mixture has a flow rate of 20 g / min (hereinafter referred to as g / min). Introduced. The temperature of the thermostatic bath was 160 ° C. The viscosity was 1 mPa · s, the Reynolds number in the reaction vessel was 40, and the residence time was 2.1 minutes. The emulsified dispersion was produced by receiving the discharged liquid in a receiving container. At this time, the pressure in the pipe was adjusted to 2.0 MPa by the exhaust pressure valve.

When the obtained emulsified dispersion was analyzed, the particle size was 76 nm, the solid content was 4.9%, and the reaction rate was 24.5%. The properties of the emulsified dispersion at the microreactor outlet are summarized in Table 1. Further, 100 g of the obtained polymerization solution was charged into a 0.5 liter reaction kettle equipped with a stirrer, a nitrogen introduction tube, and a temperature sensor for measuring the temperature in the reaction kettle while introducing nitrogen, and then sodium persulfate 0. After adding an aqueous solution in which 02 g was dissolved in 2 g of ion-exchanged water, the internal temperature of the reaction kettle was maintained at 80 ° C. for 2 hours.
The properties of the resulting emulsified dispersion are summarized in Table 2. Analysis of the resulting emulsified dispersion revealed a particle size of 97 nm, a particle size distribution variation coefficient of 14.4%, a solid content of 18.6%, and a residual monomer content of 244 ppm.
Without adding a protective colloid such as a water-soluble polymer or a surfactant, a stable emulsified dispersion in which monodispersed fine particles having a particle diameter of less than 100 nm were dispersed was obtained.

(Example 2)
An emulsified dispersion was prepared in the same manner as in Example 1 except that the temperature of the thermostatic bath was 140 ° C. When the emulsion dispersion discharged from the microreactor was analyzed, the particle size was 93 nm, the solid content was 4.6%, and the reaction rate was 23.0%.
The finally obtained emulsified dispersion had a particle size of 169 nm, a particle size distribution variation coefficient of 8.2%, a solid content of 18.6%, and a residual monomer amount of 307 ppm.
A stable emulsified dispersion in which monodisperse fine particles having a particle size of 300 nm or less were dispersed without adding a protective colloid such as a water-soluble polymer or a surfactant could be obtained. The atomic force microscope AFM observation results of the monodisperse particles obtained at this time are shown in FIGS.

(Example 3)
An emulsified dispersion was prepared in the same manner as in Example 1 except that the temperature of the thermostatic bath was 110 ° C. When the emulsion dispersion discharged from the microreactor was analyzed, the particle size was 118 nm, the solid content was 1.2%, and the reaction rate was 5.9%.
The finally obtained emulsified dispersion had a particle size of 307 nm, a particle size distribution variation coefficient of 13.2%, a solid content of 19.3%, and a residual monomer amount of 40 ppm or less.
Without adding a protective colloid such as a water-soluble polymer or a surfactant, it was possible to obtain a stable emulsified dispersion in which monodisperse fine particles of about 300 nm were dispersed.

Example 4
An emulsified dispersion was prepared in the same manner as in Example 1 except that the temperature of the thermostatic bath was 90 ° C. When the emulsion dispersion discharged from the microreactor was analyzed, the particle size was 118 nm, the solid content was 0.1%, and the reaction rate was 0.5%.
In the finally obtained emulsified dispersion, the particle size was 417 nm, the coefficient of variation of particle size distribution was 16.6%, the solid content was 18.9%, and the residual monomer amount was 40 ppm or less.
Although the particle size exceeded 300 nm and the monodispersibility was slightly inferior, a stable emulsified dispersion could be obtained without adding a protective colloid such as a water-soluble polymer or a surfactant.

(Example 5)
A sodium persulfate aqueous solution was flowed at a flow rate of 40 g / min so that the reaction mixture had a flow rate of 50 g / min (hereinafter referred to as g / min), and instead of MMA, a mixed solution of MMA 200 g and butyl acrylate (BA) 200 g was used. The emulsified dispersion was prepared in the same manner as in Example 1 except that the MMA / BA mixed solution was introduced into a reaction tube having an inner diameter of 2.17 mm at a flow rate of 10 g / min and the temperature of the thermostatic bath was 150 ° C. went. When the emulsion dispersion discharged from the microreactor was analyzed, the particle size was 116 nm, the solid content was 2.1%, and the reaction rate was 10.5%.
The finally obtained emulsified dispersion had a particle size of 172 nm, a particle size distribution variation coefficient of 10.6%, a solid content of 18.9%, and a residual monomer amount of 40 ppm or less.
A stable emulsified dispersion in which monodisperse fine particles having a particle size of 300 nm or less were dispersed without adding a protective colloid such as a water-soluble polymer or a surfactant could be obtained.

(Example 6)
An aqueous sodium persulfate aqueous solution at a flow rate of 8 g / min and an MMA / BA mixed solution at a flow rate of 2 g / min so that the reaction mixture has a flow rate of 10 g / min (hereinafter referred to as g / min), an inner diameter of 2.17 mm. The emulsified dispersion was prepared in the same manner as in Example 1 except that the temperature of the thermostatic bath was 150 ° C. When the emulsion dispersion discharged from the microreactor was analyzed, the particle size was 99.4 nm, the solid content was 4.1%, and the reaction rate was 20.5%.
In the finally obtained emulsified dispersion, the particle size was 151 nm, the coefficient of variation of the particle size distribution was 10.6%, the solid content was 17.2%, and the residual monomer amount was 95 ppm or less.
A stable emulsified dispersion in which monodisperse fine particles having a particle size of 300 nm or less were dispersed without adding a protective colloid such as a water-soluble polymer or a surfactant could be obtained.

(Example 7)
A reaction tube having an inner diameter of 2.17 mm with a sodium persulfate aqueous solution at a flow rate of 13 g / min and an MMA solution at a flow rate of 7 g / min so that the reaction mixture has a flow rate of 20 g / min (hereinafter referred to as g / min). The emulsified dispersion was prepared in the same manner as in Example 1 except that the temperature of the thermostatic bath was 150 ° C. When the emulsion dispersion discharged from the microreactor was analyzed, the particle size was 112 nm, the solid content was 9.7%, and the reaction rate was 27.7%.
100 g of the obtained polymerization solution was charged into a 0.5 liter reaction kettle equipped with a stirrer, a nitrogen inlet tube, and a temperature sensor for measuring the temperature in the reaction kettle while introducing nitrogen, and then 0.035 g of sodium persulfate. After adding an aqueous solution in which 2 g of ion exchange water was dissolved, the internal temperature of the reaction kettle was maintained at 80 ° C. for 2 hours.
In the finally obtained emulsified dispersion, the particle size was 139 nm, the variation coefficient of the particle size distribution was 14.7%, the solid content was 35.3%, and the residual monomer amount was 40 ppm or less.
Without adding a protective colloid such as a water-soluble polymer or a surfactant, it was possible to obtain a high concentration and stable emulsified dispersion in which monodisperse fine particles of 300 nm or less were dispersed.

(Example 8)
An emulsified dispersion was prepared in the same manner as in Example 1 except that a mixed solution of MMA and BA was charged in one syringe instead of MMA and the temperature of the thermostatic bath was set to 150 ° C. When the emulsified dispersion discharged from the microreactor was analyzed, the particle size was 102 nm, the solid content was 2.0%, and the reaction rate was 10.0%. Further, 1.7 g of dimethylacrylamide (DMMA) was added to 100 g of the obtained polymerization solution, and nitrogen was introduced into a 0.5 liter reaction kettle equipped with a stirrer, a nitrogen inlet tube, and a temperature sensor for measuring the temperature in the kettle. After charging while introducing, an aqueous solution in which 0.02 g of sodium persulfate was dissolved in 2 g of ion-exchanged water was added, and then the internal temperature of the reaction kettle was maintained at 80 ° C. for 2 hours.
In the finally obtained emulsified dispersion, the particle size was 212 nm, the variation coefficient of the particle size distribution was 14.4%, the solid content was 20.8%, and the residual monomer amount was 112 ppm.
A stable emulsified dispersion in which monodisperse fine particles having a particle size of 300 nm or less were dispersed without adding a protective colloid such as a water-soluble polymer or a surfactant could be obtained.

Example 9
In one syringe, a mixed solution of MMA 392 g and acrylic acid (AA) 8 g was charged instead of MMA, and an emulsion dispersion was prepared in the same manner as in Example 1 except that the temperature of the thermostatic bath was set to 150 ° C. When the emulsified dispersion discharged from the microreactor was analyzed, the particle size was 93 nm, the solid content was 6.2%, and the reaction rate was 31.0%.
In the finally obtained emulsified dispersion, the particle size was 155 nm, the particle size distribution variation coefficient was 10.1%, the solid content was 18.3%, and the residual monomer amount was 154 ppm.
A stable emulsified dispersion in which monodisperse fine particles having a particle size of 300 nm or less were dispersed without adding a protective colloid such as a water-soluble polymer or a surfactant could be obtained.

(Example 10)
Instead of a tube having an inner diameter of 2.17 mm and a length of 12 m, ten reaction vessel devices shown in FIG. 7 were connected and used as a reaction vessel.

  In one syringe, an aqueous solution in which 0.075 g of sodium persulfate was dissolved in 100 g of ion-exchanged water was prepared and charged. The other syringe was charged with methyl methacrylate (MMA). An aqueous sodium persulfate solution was introduced into the reaction vessel device at a flow rate of 8 g / min and an MMA solution at a flow rate of 2 g / min so that the reaction mixture had a flow rate of 10 g / min (hereinafter referred to as g / min). . The temperature of the thermostatic bath was 150 ° C. The viscosity was 1 mPa · s, the Reynolds number in the reaction vessel was 20, and the residence time was 1.8 minutes. The emulsified dispersion was produced by receiving the discharged liquid in a receiving container. At this time, the pressure in the pipe was adjusted to 2.0 MPa by the exhaust pressure valve.

When the obtained emulsified dispersion was analyzed, the particle diameter was 97 nm, the solid content was 4.9%, and the reaction rate was 24.5%. The properties of the emulsified dispersion at the microreactor outlet are summarized in Table 1. Further, 100 g of the obtained polymerization solution was charged into a 0.5 liter reaction kettle equipped with a stirrer, a nitrogen introduction tube, and a temperature sensor for measuring the temperature in the reaction kettle while introducing nitrogen, and then sodium persulfate 0. After adding an aqueous solution in which 02 g was dissolved in 2 g of ion-exchanged water, the internal temperature of the reaction kettle was maintained at 80 ° C. for 2 hours.
Analysis of the resulting emulsified dispersion revealed a particle size of 134 nm, a particle size distribution variation coefficient of 9.4%, a solid content of 18.9%, and a residual monomer content of 135 ppm.
Without adding a protective colloid such as a water-soluble polymer or a surfactant, a stable emulsified dispersion in which monodispersed fine particles having a particle diameter of less than 100 nm were dispersed was obtained.

(Comparative Example 1)
After stirring 80 g of ion-exchange water and 0.08 g of sodium persulfate in a 0.5 liter reaction kettle equipped with a stirrer, a nitrogen inlet tube, and a temperature sensor for measuring the temperature inside the kettle, sodium perchlorate was dissolved. While adding MMA 20 g and stirring at 150 rpm, introducing nitrogen, raising the internal temperature of the reaction kettle at 80 ° C. and holding for 2 hours, the emulsified dispersion agglomerates with time and an emulsified dispersion is obtained. There wasn't. When the aggregate was dispersed in water and the particle size was measured, the particle size was 431 nm.

(Comparative Example 2)
A 0.5 liter reaction kettle equipped with a stirrer, a nitrogen inlet tube, and a temperature sensor for measuring the temperature in the reaction kettle is charged with 80 g of ion-exchanged water and 0.08 g of polyvinyl alcohol [Kuraray Poval PVA-217 (manufactured by Kuraray Co., Ltd.)]. Then, 0.08 g of sodium persulfate was added to dissolve sodium perchlorate, then 20 g of MMA was added and stirred at 150 rpm, nitrogen was introduced and the internal temperature of the reaction kettle was raised to 80 ° C. for 2 hours. Retained. Analysis of the resulting emulsified dispersion revealed a particle size of 540 nm, a coefficient of variation of particle size distribution of 13.1%, a solid content of 21.7%, and a residual monomer amount of 40 ppm or less. In order to obtain a monodisperse emulsified dispersion, it was necessary to add a water-soluble polymer. The particle size of the fine particles contained in the obtained emulsified dispersion was over 500 nm. The obtained emulsified dispersion was slightly poor in stability, and partly coagulated and settled when stored for a while.

δ ······································································· Temperature control fluid First plate (process plate)
5a: the surface of the first plate 5b: the end surface of the first plate 5c: the end surface of the first plate 5d: the side surface of the first plate 5e: Side face of the first plate 3 .... Third plate (temperature control plate)
3a: the surface of the third plate 3b: the end surface of the third plate 3c: the end surface of the third plate 3d: the side surface of the third plate 3e: Side surface of third plate 6... Temperature control flow path with cross-sectional groove shape 6 a... Main flow path with cross-section groove shape 6 b.・ ・ ・ ・ ・ Drain-side channel with cross-sectional groove shape 8 ・ ・ ・ ・ ・ ・ Second plate (process plate)
8a: the surface of the second plate 8b: the end surface of the second plate 8c: the end surface of the second plate 8d: the side surface of the second plate 8e: Side of second plate 14 ... Fourth plate (process plate)
14a ... the surface of the fourth plate 14b ... the end surface of the fourth plate 14c ... the end surface of the fourth plate 14d ... the side surface of the fourth plate 14e ... the side surface of the fourth plate 15 ... Chemical reaction device 1
15b .... End face of the device 1 for chemical reaction 15c ... ... End face of the device 1 for chemical reaction 15d ... Side face of the device 1 for chemical reaction 15e ... Side face of the device 1 for chemical reaction 16 .... Chemical reaction device 2
16b... End surface of chemical reaction device 2 16c... End surface of chemical reaction device 2 16d... Side surface of chemical reaction device 2 16e. ... Device for chemical reaction 3
DESCRIPTION OF SYMBOLS 1b ... End face of device 3 for chemical reaction 1c ... End face of device 3 for chemical reaction 1d ... Side face of device 3 for chemical reaction 1e ... Device 3 for chemical reaction Side 2 ... The first plate (process plate)
2a: the first plate surface 2b: the first plate end surface 2c: the first plate end surface 2d: the first plate side surface 2e: Side surface of the first plate 3 .... 2nd plate (temperature control plate)
3a: the surface of the second plate 3b: the end surface of the second plate 3c: the end surface of the second plate 3d: the side surface of the second plate 3e: Side face of second plate 4... Channel with groove in cross section p0 ... Predetermined interval w0 ... Width d0 ... Depth L ... Flow Path length 30 ... Connector 31 ... Joint part 32 ... Joint part 40 ... Reaction vessel (chemical reaction device 3)
61. Compound (A) (fluid containing water-soluble radical initiator)
62... First tank 63... Compound (B) (fluid containing radical polymerizable monomer)
64 ... Second tank 65 ... Plunger pump 66 ... Plunger pump 67 ... Micromixer 68 ... Temperature controller 69 ... -Heat exchanger for cooling 70 ... Temperature controller 71 ... Exhaust pressure valve 72 ... Receptacle container 73 ... Micromixer 79 ... Used in the examples Schematic configuration diagram schematically showing the resin manufacturing equipment

Claims (3)

  In a microtubular channel having a micromixer and a heat transfer reaction vessel inside thereof, after the radical polymerizable monomer is polymerized to a reaction rate of 0.1 to 50% in the presence of a water-soluble radical initiator A method for producing an emulsified dispersion in which the obtained polymerization reaction liquid is subjected to a polymerization reaction to a reaction rate of 95% or more using a reaction kettle equipped with a stirrer, wherein the micromixer is water containing a water-soluble radical initiator. An emulsified dispersion having a structure in which a medium and a radically polymerizable monomer can be mixed, and a structure in which a flow path diameter is reduced in the flow direction of the mixed fluid Manufacturing method.   The heat transfer reaction vessel in the microtubular channel is characterized by polymerizing a fluid in which an aqueous medium containing a water-soluble radical initiator and a radical polymerizable monomer are mixed in a temperature range of 70 ° C. to 200 ° C. The method for producing an emulsified dispersion according to claim 1. 3 or 2 is continuously supplied so that the Reynolds number in a reaction vessel of a fluid obtained by mixing an aqueous medium containing the water-soluble radical initiator and a radical polymerizable monomer is 0.25 to 300. A method for producing the emulsified dispersion as described.