JP3196335B2 - Method for producing polymer fine particles and polymer fine particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polymer fine particles and a method for producing polymer fine particles, and more particularly, to a method for producing polymer fine particles having a large and uniform particle diameter and an average particle diameter of 1 to 100 .mu.m It relates to a polymer fine particle having a diameter dispersion index of 1 or less.

[0002]

2. Description of the Related Art Polymer particles used for column fillers, various spacers, diagnostic drug carriers, and the like are required to have a large particle size of 1 to 100 μm and have a uniform particle size. As one method to meet this demand, a method has been proposed in which a polymerizable monomer is added in the presence of a seed latex to perform seed emulsion polymerization. However, 1 μm
In order to obtain polymer particles having the above-mentioned particle diameter, it is necessary to extremely slow down the polymerization reaction, which is not industrially practical. A method has been proposed in which a polymerizable monomer is mixed with water, and an emulsion obtained by dispersion treatment with a powerful stirrer, homogenizer, colloid mill, ultrasonic dispersion emulsifier, or the like is polymerized. However, in this method, even if stirring is performed for a long time with a strong stirring force, the uniformity of the particle diameter of the polymer particles is not sufficient, and it is impossible to control the particle diameter to an arbitrary size. A method in which the swelling aid is absorbed by the seed particles, and then the polymerizable monomer is further absorbed to carry out polymerization (JP-A-54-1).
26288). However, in this method, the swelling aid and the polymerizable monomer need to be absorbed in the seed particles in two stages, and the process is complicated. As another method, a method has been proposed in which a liquid to be a dispersed phase is pressed into a liquid to be a continuous phase through a microporous membrane having a uniform pore diameter to obtain an emulsion (Japanese Patent Laid-Open No. 2-95433). ing. Indeed, by this method,
Initially, an emulsion having a uniform particle size can be obtained, but as time elapses, the emulsion has a wide particle size distribution, so that even when this emulsion is polymerized, the particle size of the polymer particles becomes non-uniform. In addition, there is a method of classifying polymer particles having a wide particle diameter distribution obtained by the above-described method and the like to classify the particle diameters, but this method is complicated and time-consuming, but the particle diameter is uniform. The yield of good polymer particles is low. Therefore, there is a demand for a method for producing uniform polymer fine particles having a large particle diameter.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing uniform polymer fine particles having a large particle diameter and a polymer fine particle having an average particle diameter of 1 to 100 .mu.m and a particle diameter dispersion index of 1 or less. Is to provide. The present inventors have conducted intensive studies to achieve this object, and as a result, obtained an emulsion obtained by extruding an oil phase liquid containing a specific organic compound and a polymerizable monomer through a porous membrane into an aqueous phase liquid. It has been found that this object can be achieved by polymerization,
The present invention has been completed based on this finding.

[0004]

According to the present invention, an oil phase containing an organic compound A having a solubility in water at 20 ° C. of 0.015% by weight or less and a molecular weight of 5000 or less and a polymerizable monomer is provided. A method for producing polymer fine particles, comprising polymerizing an emulsion obtained by extruding a liquid through a porous membrane into an aqueous phase liquid, and polymer fine particles obtained by this production method, wherein the average particle diameter is 1 to 3. 100 μm
The polymer fine particles having a particle diameter dispersion index of 1 or less are provided.

The oil phase liquid used in the present invention has a solubility in water at 20 ° C. of 0.015% by weight or less and a molecular weight of 50%.
It consists of an organic compound A and a polymerizable monomer of 00 or less.

The organic compound A used in the present invention is an organic compound which does not cause a polymerization initiation reaction and does not undergo a polymerization growth reaction. The solubility of organic compound A in water at 20 ° C. is 0.1.
015% by weight or less, preferably 0.01% by weight or less, and a molecular weight of 5000 or less, preferably 80 to 4500.
It is. The solubility in water at 20 ° C. is 0.015% by weight.
When an organic compound A having a super molecular weight or a molecular weight exceeding 5,000 is used, the particle size distribution of the polymer fine particles is widened. When an oligomer is used as the organic compound A, the molecular weight is a weight average molecular weight of the oligomer measured by gel permeation chromatography based on polystyrene. The solubility of the organic compound A in the polymerizable monomer is not particularly limited.

As the organic compound A, for example, hexane,
Alkanes such as heptane and octane; 1-chlorododecane, 2-bromododecane, 2-chloroundecane, 1-
Halogenated hydrocarbons such as chlorodecane; esters such as dioctyl adipate and stearyl methacrylate; oligomers having a molecular weight of 5,000 or less obtained by polymerizing a hydrophobic polymerizable monomer described below in the presence of a chain transfer agent. Can be. In particular, it is preferable to use an oligomer obtained by polymerizing a halogenated hydrocarbon such as 1-chlorododecane or a hydrophobic polymerizable monomer since more uniform polymer fine particles can be obtained.

The amount of the organic compound A is from 0.2 to 10% by weight, preferably from 0.5 to 10% by weight, based on the polymerizable monomer.
8% by weight. When the content is less than 0.2% by weight, the particle size distribution of the polymer fine particles is widened. On the contrary, when the content is more than 10% by weight, not only the average particle size of the polymer fine particles is reduced, but also the organic compound A becomes an impurity. It is not preferable because the fine particles cannot be used as a drug carrier or the like.

The polymerizable monomer used in the present invention is a hydrophobic polymerizable monomer having a solubility in water at 20 ° C. of 10% by weight or less. For example, vinyl aromatic monomers such as styrene, alkylstyrene, and vinylnaphthalene; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ( (Meth) trifluoroethyl acrylate, (meth)
Tetrafluoropropyl acrylate, dibutyl maleate, dibutyl fumarate, ethyl maleate, methoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxyethoxyethyl (meth) acrylate,
Cyanomethyl (meth) acrylate, 2-cyanoethyl (meth) acrylate, 1-cyanopropyl (meth) acrylate, 2-ethyl-6-cyanohexyl (meth) acrylate, 3-cyanopropyl (meth) acrylate, Hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, 2-
Ethylenically unsaturated carboxylic acid ester monomers such as sulfoethyl acrylate and 2-sulfopropyl methacrylate; fluoroalkyl vinyl ethers such as fluoroethyl vinyl ether; vinyl pyridines; non-alkyl groups such as vinyl norbornene, dicyclopentadiene and 1,4-hexadiene Conjugated diene monomers; olefins such as ethylene and propylene; 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene and chloroprene Conjugated diene monomers; and the like. These hydrophobic polymerizable monomers can be used alone or in combination of two or more.

The polymerizable monomer used in the present invention may contain a hydrophilic polymerizable monomer, if necessary. The hydrophilic polymerizable monomer is one having a solubility in water at 20 ° C. of more than 10% by weight. As a specific example,
(Meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N
-Ethylenically unsaturated amide monomers such as propoxymethyl (meth) acrylamide; ethylenically unsaturated nitrile monomers such as acrylonitrile, methacrylonitrile, fumaronitrile, α-chloroacrylonitrile, α-cyanoethylacrylonitrile; acrylic acid, methacrylic acid acid,
Itaconic acid, maleic acid, fumaric acid, maleic anhydride,
And ethylenically unsaturated carboxylic acid monomers such as citraconic anhydride and salts thereof. Particularly, a hydrophilic polymerizable monomer that is miscible with the above-described hydrophobic polymerizable monomer is preferably used. The amount of the hydrophilic polymerizable monomer used is less than 10% by weight, preferably 8% by weight based on the hydrophobic polymerizable monomer.
Is less than. When the content is 10% by weight or more, the particle size distribution of the polymer fine particles becomes wide.

The oil phase liquid used in the present invention preferably contains a polymerization initiator in order to obtain fine polymer particles having a more uniform particle diameter. Examples of the polymerization initiator include peroxides such as lauroyl peroxide, octanoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, and benzoyl peroxide; azo compounds such as azobisisobutyronitrile; Persulfates such as potassium sulfate and ammonium persulfate; and the like. Further, a redox polymerization initiator obtained by combining a peroxide and a reducing agent can also be used. In particular, a polymerization initiator having a solubility in water at 20 ° C. of 0.015% by weight or less, such as octanoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, and benzoyl peroxide, is preferably used. The amount of the polymerization initiator that can be contained in the oil phase liquid is 0.1 to the polymerizable monomer.
05 to 10% by weight. When the content is 10% by weight or more, it is difficult to control the polymerization reaction, which is not preferable.

The method for preparing the oil phase liquid used in the present invention is not particularly limited. For example, a method in which an organic compound A is added to a polymerizable monomer and dispersed or dissolved by stirring, or a method in which a polymerizable monomer is added to the organic compound A Any method such as a method of adding and stirring and dispersing or dissolving the body may be adopted.

The aqueous phase liquid used in the present invention is water or a liquid in which an emulsifier or a water-soluble polymer is dissolved in water. In particular, when a liquid in which a water-soluble polymer is dissolved in water is used as the aqueous phase liquid,
Aggregates are less likely to occur during polymerization, and polymer fine particles having a more uniform particle size can be obtained.

The water-soluble polymer has a molecular weight of 2,000 or more,
Preferably it is 5000 or more. Specific examples thereof include hydroxyl group-containing polymers such as polyvinyl alcohol; polyvinyl esters such as polyvinyl acetate; polyethers such as polyethylene oxide; amide group-containing polymers such as polyacrylamide; and carboxyl group-containing polymers such as polyacrylic acid. Polyvinylpyrrolidone; celluloses; polysaccharides; These water-soluble polymers can be used alone or in combination of two or more. In particular, a water-soluble polymer used as a dispersant in polymerization of polyvinyl alcohol, polyacrylamide, polyacrylic acid, polyvinyl acetate and the like is preferable. When a liquid in which a water-soluble polymer is dissolved in water is used as the aqueous phase liquid, the amount of the water-soluble polymer used is 0.1 to the polymerizable monomer.
It is 1 to 20% by weight, preferably 1 to 10% by weight.
If the amount is less than 0.1% by weight, agglomerates are formed during polymerization. Conversely, if it exceeds 20% by weight, it is not economical.

Examples of the emulsifier include nonionic emulsifiers such as polyoxyethylene alkylene ether, polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ester and polyoxyethylene sorbitan alkyl ester; myristic acid, palmitic acid, oleic acid and linolenic acid. Fatty acids such as acids and their salts,
Anionic emulsifiers such as alkyl allyl sulfonates, higher alcohol sulfates and alkyl sulfosuccinic acids;
Ammonium chlorides such as trimethylammonium chloride and dialkylammonium chloride, and cationic emulsifiers such as benzylammonium salts and the like and quaternary ammonium salts; sulfoesters of α, β-unsaturated carboxylic acids and α, β-unsaturated carboxylic acids Copolymerizable emulsifiers containing double bonds such as sulfate esters and sulfoalkylaryl ethers can be mentioned. These emulsifiers can be used alone or in combination of two or more. When a liquid in which an emulsifier is dissolved in water is used as the aqueous phase liquid, the amount of the emulsifier used is 0.1 to 10% by weight based on the polymerizable monomer. If it is less than 0.1% by weight,
Aggregates form during polymerization. Conversely, if it exceeds 10% by weight, the average particle size of the polymer fine particles becomes small.

The porous membrane used in the present invention is a porous membrane having a uniform pore size. The uniform pore diameter is defined as the pore diameter (φ) when the cumulative amount from the larger pore diameter is 10% in the relative cumulative pore diameter distribution curve.
₁₀ ) divided by the pore diameter at 90% (φ ₉₀ ) is 1
It is within the range of ~ 2.5. Outside this range,
The particle size of the polymer fine particles becomes non-uniform. Further, in order to maintain the mechanical strength of the membrane and reduce the pressure loss, the average pore diameter of the porous membrane is preferably 0.1 to 50 μm in median diameter, and the thickness of the porous membrane is 0 μm. .3-2
mm.

Specific examples of the porous film include porous ceramics such as alumina, zirconia, magnesia, araldite, and carborundum; CaO-B
_{2 O 3 -SiO 2 -Al 2 O} 3 based porous glass (Japanese 62-25618 _{JP), CaO-B 2 O 3} -SiO
₂ -Al ₂ O ₃ -Na ₂ O-based porous glass, CaO-B
Film-shaped molded articles of porous glass such as ₂ O ₃ —SiO ₂ —Al ₂ O ₃ —Na ₂ O—MgO based porous glass (Japanese Patent Application Laid-Open No. 61-40841). In particular, a porous glass film-shaped product is preferably used because the average pore diameter can be arbitrarily adjusted and the pore diameter is uniform. The porous membrane used in the present invention may be one that has been surface-treated with a silylating agent, a silane coupling agent, or the like, if necessary.

In the present invention, an oil phase solution is extruded through a porous membrane into an aqueous phase solution to obtain an emulsion, and then the emulsion is polymerized.

In order to extrude the oil phase liquid through the porous membrane into the aqueous phase liquid, the pressure (P _O ) on the oil phase liquid side partitioned by the porous membrane as shown in FIGS. Pressure (P
_W ) must be higher. Specific methods for extruding the oil phase liquid into the aqueous phase liquid include, for example, a method in which the oil phase liquid side is pressurized with a compressor or the like; a method in which the aqueous phase liquid side is depressurized with a vacuum pump or the like; A method of adjusting the pressure difference from the phase liquid side by the difference between the flow rates of the oil phase liquid and the aqueous phase liquid, and the like can be given.

When the oil phase liquid is extruded into the aqueous phase liquid, the oil phase liquid is preferably fluidized by stirring, circulation or the like in order to prevent phase separation or sedimentation of the polymerizable monomer or the organic compound A. In addition, as shown in FIG. 2, the aqueous phase liquid is preferably fluidized by stirring, circulation and the like in order to facilitate the separation of the oil phase liquid extruded into the aqueous phase liquid from the porous membrane.

The pressure difference between the oil phase liquid side and the aqueous phase side is preferably 1.1 to 6 times the pressure loss of the porous membrane separating the oil phase liquid and the aqueous phase liquid. If it is less than 1.1 times, the pushing speed of the oil phase liquid will be low. Conversely, if it exceeds 6 times, the particle diameter of the polymer fine particles becomes non-uniform. The pressure loss of the porous membrane is a value determined by the interfacial tension, contact angle, viscosity, pore diameter, thickness and the like of the oil phase liquid.

When the oil phase liquid is extruded into the aqueous phase liquid, the temperature of the oil phase liquid is not particularly limited. However, when a polymerization initiator is contained in the oil phase liquid, the polymerization is carried out by the polymerization initiator. The temperature is preferably lower than the temperature at which the polymerization reaction of the reactive monomer starts, and is usually 0 to 50 ° C. Further, the temperature of the aqueous phase liquid is not particularly limited, and need not be the same as the temperature of the oil phase liquid.

The amount of the oil phase liquid extruded into the aqueous phase liquid is 1 to 100 parts by weight, preferably 5 to 100 parts by weight, based on 100 parts by weight of the aqueous phase liquid.
７０70 parts by weight. When the amount is less than 1 part by weight, the productivity of the polymer fine particles is low because the emulsion concentration is low. Conversely 10
If it exceeds 0 parts by weight, the particle size of the polymer fine particles will be non-uniform.

The polymerization of the emulsion obtained by extruding the oil phase liquid through the porous membrane into the aqueous phase liquid is carried out by polymerizing the emulsion as it is in the container used for extruding the oil phase liquid into the aqueous phase liquid, or The emulsion is transferred to another polymerization reactor and polymerized. When the emulsion is transferred to another polymerization reactor for polymerization, the method of charging the emulsion to the polymerization reactor is not particularly limited, and the method of charging the emulsion in a batch to the reactor, the emulsion continuously or in the polymerization reactor. A method such as an intermittent supply method can be appropriately adopted.

As the polymerization method, a suspension polymerization method is usually used. The type of the polymerization reactor and the stirring method are not particularly limited. The polymerization temperature varies depending on the polymerization initiator used, but is usually 0 to 90 ° C.

As the polymerization initiator, the same polymerization initiator as described above which can be contained in the oil phase liquid is used. The polymerization initiator is added to the reactor during the polymerization when the polymerization initiator is not contained in the oil phase liquid, and is necessary for the polymerization when the polymerization initiator is contained in the oil phase liquid. To the reactor according to. The method of adding the polymerization initiator is not particularly limited. For example, a method in which the polymerization initiator is charged into the reactor all at once; a method in which the polymerization initiator is continuously or intermittently supplied; and a part of the polymerization initiator is added. Any method such as a method in which the reactor is charged in a lump and the remaining portion is continuously or intermittently supplied and added may be used. When the polymerization initiator is not contained in the oil phase liquid, the amount of the polymerization initiator is usually 0.05 to 10% by weight based on the polymerizable monomer. When a polymerization initiator is contained in the oil phase liquid, it is added in a range where the total amount of the polymerization initiator used is 10% by weight or less based on the polymerizable monomer. If the content is less than 0.05% by weight, the polymerization reaction is too slow, so that it is not practical. Conversely, if it exceeds 10% by weight, it becomes difficult to control the polymerization reaction.

If necessary, a water-soluble polymer, an emulsifier, a chain transfer agent and the like are supplied to the reactor all at once when starting the polymerization, or continuously or intermittently during the polymerization. Can be added. As the water-soluble polymer, the same water-soluble polymer that can be contained in the aqueous phase liquid is used. The amount of the water-soluble polymer added is 0.1 to 20% by weight based on the polymerizable monomer when a liquid in which the water-soluble polymer is not dissolved in water is used as the aqueous phase liquid. When a liquid in which a water-soluble polymer is dissolved in water is used as the aqueous phase liquid, the total amount of the water-soluble polymer used is within a range of 20% by weight or less. If it exceeds 20% by weight, it is not economical. Conversely, if it is less than 0.1% by weight, agglomerates are formed during polymerization.

As the emulsifier, the same emulsifier that can be contained in the aqueous phase liquid is used. When a liquid in which the emulsifier is not dissolved in water is used as the aqueous phase liquid, the amount of the emulsifier added is 0.1 to 10% by weight based on the polymerizable monomer. When a liquid in which an emulsifier is dissolved in water is used as the aqueous phase liquid, the total amount of the emulsifier used is within a range of 10% by weight or less. If the amount is less than 0.1% by weight, aggregates are formed during polymerization. Conversely, if it exceeds 10% by weight, the particle size of the polymer fine particles becomes small.

As the chain transfer agent, those usually used in radical polymerization may be used. For example, mercaptans such as t-dodecyl mercaptan; xanthogen disulfide; halogenated hydrocarbons such as carbon tetrachloride; α-methylstyrene dimer and the like. Oligomers of aromatic vinyl monomers;
And the like. The amount used is not particularly limited.

[0030]

As described above, according to the present invention, a method for producing uniform polymer fine particles having a large particle size and a polymer fine particle having an average particle size of 1 to 100 μm and a particle size dispersion index of 1 or less are provided. Provided.

[0031]

The present invention will be described below in more detail with reference to examples. In the examples, parts and percentages are by weight unless otherwise specified.

[Evaluation Method] (Average Particle Size and Particle Size Distribution of Polymer Fine Particles) Measured with a Coulter Multisizer (manufactured by Coulter). The average particle diameter was evaluated by the median diameter (D ₅₀ ), and the particle diameter distribution was evaluated by the particle diameter dispersion index shown in Formula 1.

[0033]

(Equation 1)

Here, D ₁₀ , D ₅₀ and D ₉₀ are the cumulative amounts of 10%, 50% and 9 respectively in the cumulative particle size distribution curve.
It is the particle diameter when indicating 0%.

[Membrane Emulsion Apparatus] As shown in FIG. 3, the membrane emulsification apparatus used in the embodiment is a double pipe (9) using a cylindrical porous membrane (3) as an inner pipe, a pump (5), It comprises an oil phase liquid container (10), an aqueous phase liquid container (11) and a valve.
The aqueous phase liquid (2) is pump (5), and the aqueous phase liquid container (11)
From there, it flows through the inner pipe of the double pipe (9) via the aqueous phase liquid line (7), and returns to the aqueous phase liquid container (11). On the other hand, the oil phase liquid (1) flows from the oil phase liquid container (10) to the outer pipe of the double pipe (9) via the oil phase liquid line (8) by another pump, and Return to the container (10). The pressure difference between the oil phase liquid side and the aqueous phase liquid side is adjusted by adjusting the flow rate of the oil phase liquid and the aqueous phase liquid by opening the valve so that the oil phase liquid side pressure is higher than the aqueous phase liquid side pressure. Make it higher. The oil phase liquid is extruded from the outer tube of the double tube (9) through the porous membrane into the inner tube to form emulsion particles. The particles of the emulsion flow along the flow of the aqueous phase liquid. Emulsions increase in concentration over time. After a predetermined time, a desired emulsion is obtained in the aqueous phase liquid container (2).

Example 1 100 parts of styrene, 5 parts of 1-chlorododecane (solubility in water at 20 ° C .: 0.01% by weight or less) and 2 parts of benzoyl peroxide were mixed and stirred to obtain an oil phase liquid. On the other hand, 5 parts of polyvinyl alcohol (Gohsenol GH23: manufactured by Nippon Synthetic Chemical Co., Ltd.) was added to 1000 parts of distilled water and stirred to obtain an aqueous phase solution in which polyvinyl alcohol was dissolved. After each of the oil phase liquid and the aqueous phase liquid was charged into a predetermined container of a membrane emulsifying apparatus as shown in FIG. 3, the average pore diameter (median diameter) was 1.1 μm.
m, φ10 / φ90 = 1.1, an aqueous phase liquid (liquid temperature 20 ° C) is circulated inside a cylinder made of porous glass having a thickness of 1 mm,
An oil phase liquid (liquid temperature of 20 ° C.) is applied from the outside of the cylinder to a pressure difference of 0.5.
The emulsion was extruded into the cylinder at 2 kg / cm @ 2. Next, the inside of a 2 l reactor equipped with a stirring blade, a cooling condenser, a nitrogen gas inlet tube and a thermometer was replaced with nitrogen,
The whole amount of the emulsion was charged into the reactor, heated to 70 ° C., and continuously stirred for 15 hours , followed by filtration and drying to obtain polymer fine particles (a). Table 1 shows the evaluation results of the polymer fine particles.

Example 2 A cylinder made of porous glass having an average pore diameter (median diameter) of 2.9 μm, φ ₁₀ / φ ₉₀ = 1.2 and a thickness of 1 mm was used instead of the cylinder made of porous glass of Example 1. And polymer fine particles (b) were obtained in the same manner as in Example 1 except that the pressure difference was 0.26 kg / cm ² . Table 1 shows the evaluation results of the polymer fine particles.

Example 3 Except that an oil phase liquid and an aqueous phase liquid having the formulation shown in Table 1 were used,
Polymer fine particles (c) to (g) were obtained in the same manner as in Example 1. Table 1 shows the evaluation results of these polymer fine particles.

Comparative Example 1 Except that the oil phase liquid and the aqueous phase liquid having the formulation shown in Table 1 were used,
Polymer fine particles (h) to (j) were obtained in the same manner as in Example 1. Table 1 shows the evaluation results of these polymer fine particles.

Comparative Example 2 An oil phase liquid and an aqueous phase liquid having the same composition as the oil phase liquid and the aqueous phase liquid used in Example 1 were mixed, and mixed with a magnetic stirrer.
After dispersing for 0 minute, the mixture was dispersed and mixed for 30 minutes with an ultrasonic emulsifier (UH-8-3, manufactured by Ultrasonic Industry Co., Ltd.) to obtain an emulsion. Next, the inside of a 2 liter reactor equipped with a stirring blade, a cooling condenser, a nitrogen gas inlet tube, and a thermometer was purged with nitrogen, the entire amount of the emulsion was charged into the reactor, the temperature was raised to 70 ° C., and stirring was performed for 15 hours. Then, polymer fine particles (k) were obtained. Table 1 shows the evaluation results of the polymer fine particles.
Shown in

[0041]

[Table 1]

According to Table 1, the solubility in water was 0.015.
When the organic compound is used in an amount of more than 1% by weight (polymer fine particles (i)) or an organic compound having a molecular weight of more than 5,000 (polymer fine particles (j)), the particle diameter of the polymer fine particles is not uniform. You can see that there is. It can be seen that the particle size of the polymer fine particles is not uniform in the mechanical dispersion method such as ultrasonic waves (polymer fine particles (k)). On the other hand, according to the present invention, it is understood that uniform polymer fine particles having a large particle diameter can be obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a mechanism in which an oil phase liquid is extruded through a porous membrane into an aqueous phase liquid to form an emulsion.

FIG. 2 is an enlarged view of the vicinity of the porous membrane of FIG.

FIG. 3 is a conceptual diagram of a membrane emulsifying device.

[Explanation of symbols]

 1. Oil phase liquid 2. Water phase liquid 3. Porous membrane 4. Emulsion particles 5. Pump 6. Flow meter 7. Water phase liquid line 8. Oil phase liquid line 9. ..Double pipe 10..Oil phase liquid container 11..Aqueous phase liquid container

Claims (2)

(57) [Claims] 1. The solubility in water at 20 ° C. is 0.015.
Organic compound A having a molecular weight of 5,000 or less by weight or less
And producing an emulsion obtained by extruding an oil phase solution containing a polymerizable monomer through a porous membrane into an aqueous phase solution. 2. Polymer fine particles obtained by the production method according to claim 1, wherein the average particle diameter is 1 to 100 μm and the particle diameter dispersion index is 1 or less.