JPH0211603A - Production of monodisperse polymer particle - Google Patents

Abstract

PURPOSE:To produce monodisperse polymer particles having particle diameters larger than several mum with high productivity, by using a specific water-miscible org. solvent as both a solvent and a dispersion medium for a monomer and putting ice into a disperse system to increase the water content of the disperse system. CONSTITUTION:A monomer, a nucleating agent or seed polymer particles which swell by the monomer, a dispersion stabilizer and an oil-soluble polymn. initiator are dissolved or dispersed in a water-miscible org. solvent which dissolves the monomer but does not dissolve a polymer derived from the monomer, or in a mixture of said water-miscible org. solvent with water. By cooling the resulting disperse system to 0 deg.C, putting and dispersing ice in the disperse system with stirring, and heating to melt the ice to thereby increase the water-content of the disperse system, oil droplet particles comprising oil-soluble matters including the monomer, the polymn, initiator, etc., with the nucleating agent being at the center of the particles are formed, or the seed polymer particles are allowed to absorb the monomer and the polymn. initiator. The monomer in the oil droplet particles or absorbed in the seed polymer particles is selectively polymerized.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing monodisperse polymer particles, and more specifically, the present invention relates to a method for producing monodisperse polymer particles, and more specifically, the present invention relates to a method for producing monodisperse polymer particles, and more specifically, the particle size distribution is monodisperse without generating fine defective particles, and the particle size is The present invention relates to a method for producing spherical polymer particles having a diameter of several μm or more.

[Conventional technology]

Conventionally, emulsion polymerization, suspension polymerization, and dispersion polymerization are known as methods for producing spherical polymer particles. Each of these polymerization methods has its own characteristics in terms of particle size, particle size distribution, and molecular weight. In the emulsion polymerization method, monodisperse fine particles of polymers can be obtained, but only small particles with a particle size of 1°0 μm or less can be obtained. . On the other hand, although suspension polymerization can produce particles with a large particle size of 10 μm or more, it is only possible to synthesize particles with a polydisperse particle size distribution. Furthermore, in dispersion polymerization, although there are reports of the synthesis of monodisperse particles with a particle size of about 7 μm, it is not easy to control the molecular weight and particle size of the polymer constituting the particles, and the amount of monodisperse particles that can be used is limited. The body is also limited.

To improve these shortcomings, Journal of Polymer Science; Polymer Symposium 72
, 225-240 (1985), monodisperse particles synthesized by emulsion polymerization are swollen with oligomers or solvents,
A "two-step swelling method" has been proposed in which the material is then swollen with a monomer and then polymerized.

[Problems to be Solved by the Invention] However, the method of the above-mentioned prior art requires a complicated means of two-stage swelling, and the swelling operation itself requires a long time, resulting in a lack of productivity. be.

If spherical polymer particles with a particle size on the order of several μm to several tens of μm and a monodisperse particle size distribution can be obtained, they will have a sharp particle size distribution and do not require operations such as classification, so they can be used for electrophotography. It is expected to be used as a gap adjuster for toner liquid crystal display panels, standard particles for Coulter counters, column packing materials for chromatography, carriers for immunodiagnostics, bases for cosmetics, and other applications.

Therefore, an object of the present invention is to provide a method for producing monodisperse polymer particles having a particle size of several μm or more with good productivity.

Another object of the present invention is to shorten the solubility of the monomer in the dispersion medium by utilizing it to form monomer-containing oil droplets or to absorb the monomer in seed polymer particles. The object of the present invention is to provide a method capable of producing large-sized monodisperse polymer particles in a timely and efficient manner.

[Means for solving problems]

A water-miscible organic solvent that dissolves the monomer but does not dissolve the polymer, or a mixture of the water-miscible organic solvent and water, is used as the solvent to dissolve the monomer, the nuclear material, or the monomer. After dissolving or dispersing the swellable seed polymer particles, dispersion stabilizer, and oil-soluble polymerization initiator in the solvent, cooling the dispersion system to 0 ° C., and further dispersing ice with stirring, increasing the concentration of water in the dispersion by heating the dispersion to melt ice in the dispersion to form oil droplets consisting of a monomer and a polymerization initiator centered on the core material; Alternatively, a monomer and a polymerization initiator are absorbed into the nuclide polymer particles, and the monomers in the nuclear oil droplets or the monomers absorbed in the seed polymer particles are selectively polymerized. The object of the invention is achieved by producing coalesced particles.

[Effect]

The present inventors previously reported in Japanese Patent Applications No. 17321/1982 and 94284/1983 that they increased the concentration of water in the dispersion system to reduce the solubility of monomers in the dispersion system, and The monomer is precipitated into oil droplet particles consisting of a monomer and a polymerization initiator, or the monomer and the polymerization initiator are absorbed into the seed polymer particles, and the seed polymer particles are swollen. The particle size is increased to several microns or more, and the monomer in the oil droplet particles or the monomer absorbed in the seed polymer particles is selectively polymerized to form spherical particles with a particle size of several μm or more. A method for producing monodisperse polymer particles was proposed.

As a result of further investigation, the present inventors found that in order to increase the concentration of water, the method of simply dropping water into the dispersion system,
Because it is not evenly and uniformly supplied to the entire dispersion system, there are areas around the dropped water where the concentration of water is locally high, and the monomers in those areas are surrounded by water with which they have no affinity. ,
- Formation of oil droplet particles or swelling of seed polymer particles occurs, and only some particles around the water droplets grow, and eventually only those particles have a particle size that is smaller than that of other particles. It was discovered that if the concentration gradient of the layer increases, the monomer will precipitate in places other than the core material and seed polymer particles, forming oil droplets.

Therefore, in the present invention, the concentration of water in the dispersion system is increased by first cooling the dispersion system to 0°C, dispersing ice in the dispersion system, and then heating the dispersion system to make the dispersed ice. By dissolving the monomer, the concentration gradient in the dispersion system is eliminated as much as possible, and the monomer is precipitated or absorbed only in the core material or seed polymer particles, thereby achieving more monodisperse particle growth.

That is, when the dispersion system is cooled to O'C and then ice is added to the cooled dispersion system and stirred, the ice becomes uniformly dispersed throughout the dispersion system. Then, when this dispersion system is heated, the ice dispersed throughout the dispersion system begins to melt, and the melted hydraulic pressure permeates the entire dispersion system, causing a decrease in the solubility of the monomer to occur almost equally throughout the system, resulting in localized The concentration of water does not increase, and the precipitated monomer is precipitated and absorbed only by the dispersed core or seed polymer particles, and grows into monodisperse particles with uniform particle size in a short period of time and efficiently. can do.

In the present invention, it is important that polymerization is initiated selectively only with respect to the monomers absorbed in the oil droplets or the seed polymer; if the polymerization is initiated with respect to the monomers dissolved in the dispersion medium, Then, the monomer is absorbed into the resulting polymer particles, causing particle growth, making it difficult to obtain monodisperse polymer particles.The polymerization initiator is oil-soluble, and the monomer It needs to be absorbed into the oil droplet particles or seed polymer particles along with the oil droplets. In addition, when an oil-soluble substance is dissolved together with the nuclear material, seed polymer particles, dispersion stabilizer, polymerization initiator, etc., it forms oil droplets with other oil-soluble substances or is absorbed by the seed polymer and generated. It can also be incorporated into polymer particles to add functionality to the polymer. For example, colored particles can be obtained by dissolving oil-soluble dyes.

[Preferred aspect]

The monomer used in the present invention is an ethylenically unsaturated monomer having radical polymerizability, and suitable examples thereof include monovinyl aromatic monomer, acrylic monomer, and vinyl ester monomer. monomers, vinyl ether monomers, diolefin monomers, monoolefin monomers, halogenated olefin monomers, polyvinyl monomers, and the like.

The monovinyl aromatic monomer has the formula (wherein R1 is a hydrogen atom, a lower alkyl group, or a halogen atom, and R2 is a hydrogen atom, a lower alkyl group, a halogen atom, an alkoxy group, an amino group, a nitro group, a vinyl or carboxyl group), such as styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene,
Examples of o-1m-1p-chlorostyrene, p-ethylstyrene, sodium styrene sulfonate, and divinylbenzene may be used alone or in combination of two or more, and the other monomers mentioned above include the following, respectively. Can be mentioned.

(In the formula, R1 is a hydrogen atom or a lower alkyl group, and R4 is a hydrogen atom, a hydrocarbon group having up to 12 carbon atoms, a hydroxyalkyl group, a vinyl ester group, or an aminoalkyl group). Acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, β- Ethyl hydroxyacrylate, γ-butyl hydroxylate, δ-butyl hydroxyacrylate, β-hydroxyethyl methacrylate, γ-aminopropyl acrylate, r-N,N-diethylaminopropyl acrylate, ethylene glycol dimethacrylate, Tetraethylene glycol dimethacrylate, etc.

Vinyl esters of CH2=CH (wherein R5 is a hydrogen atom or a lower alkyl group), such as vinyl formate, vinyl acetate, vinyl propionate, etc.

Vinyl ethers of the formula (wherein R8 is a monovalent hydrocarbon group having up to 12 carbon atoms) such as vinyl methyl ether, vinyl ethyl ether, vinyl-n-butyl ether, vinyl phenyl ether, vinyl cyclohexyl ether, etc.

Diolefins of the formula (wherein each of R?, Re, Rq is a hydrogen atom, a lower alkyl group or a halogen atom), especially butadiene, isoprene, chloroprene and the like.

Monoolefins of the formula (wherein each of R2° and R11 is a hydrogen atom or a lower alkyl group), particularly ethylene, propylene, isoprene, butene-1, pentene-1,4-methylpentene-1, etc.

Examples of halogenated olefin monomers include vinyl chloride, vinylidene chloride, etc., and examples of polyvinyl monomers include divinylbenzene, diallylphthalate,
Triallyl cyanurate and the like can be mentioned.

These monomers can be used alone or in combination of two or more. Preferred monomers are styrene, (meth)acrylate, styrene/(meth)acrylate, styrene/divinylbenzene.

Examples of organic solvents miscible with Mi-colored chestnut water include methanol, ethanol,
Lower alcohols such as isopropanol; polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, diethylene glycol, and triethylene glycol; cellosolves such as methyl cellosolve and ethyl cellosolve; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran esters such as ethyl acetate; organic acids such as formic acid, acetic acid, and propionic acid; among these, the monomer dissolves, but the polymer does not dissolve. used in combination. Organic solvents that have excellent monomer solubility, can be mixed with water in any ratio, and are therefore particularly useful for the purposes of the present invention are lower alcohols such as ethanol.

This water-miscible organic solvent can be used alone or
It can also be used in the form of a mixture with water.

In the latter case, it is desirable to contain as much water as possible without practically reducing the solubility of the monomer.
The mixing ratio is determined by the monomer and organic solvent used.
For example, when lower alcohol is used as the organic solvent, the organic solvent and water can be used in a volume ratio of 10:1 to 3:5, particularly 4:3 to 3:4.

Wataru Hiratate The core substance used in the present invention is a substance that serves as a nucleus when monomers precipitated by utilizing the decrease in monomer solubility in a specific solvent and dispersion medium form oil droplets, and at the same time It acts as the core of the polymer.

This nuclear material may be any conventionally known fine particles, such as 81□03
, MnO□, 5iOz, SnO2, rhoz, Ti0
Z, ZnO, Mob, silica, gold, silver, inorganic pigments, organic pigments, magnetic powder, etc.

Among these, when magnetic powder is used as a nuclear material, magnetic particles can be obtained. Magnetic powders include ferromagnetic metals such as iron, cobalt, and nickel, or magnetite,
Alloys and compounds such as hematite and ferrite are used.

Further, when carbon black, an inorganic pigment, or an organic pigment is used as a core material, colored particles can be produced without adding any coloring agent. As the pigment, commonly used pigments can be used.

The above-mentioned core material has a monodisperse particle size distribution, and the particle size is generally in the range of 0.01 to 20 μm, particularly preferably in the range of 0.5 to 10 μm.

The seed polymer particles used in the present invention exhibit swellability with respect to the above-mentioned monomers, and are polymers obtained by polymerizing one or more of the above-mentioned monomers. It is a coalesced particle. These polymer particles are generally formed from the same type of monomer as the monomer used, but they may also be formed by polymerizing a monomer different from this monomer. An example is a combination of styrenic polymer particles and a styrenic monomer, and an example of the latter is a combination of acrylic polymer particles and a styrenic monomer.

The seed polymer particles have a monodisperse particle size distribution,
It is desirable that the particle size is generally in the range of 0.01 to 50 µm, particularly 0.5 to 20 t1m.Such seed polymer particles can be produced by a dispersion polymerization method, an emulsion polymerization method, or a polymerization method known per se. It can be easily obtained by crushing and classifying.

As the dispersion stabilizer for improving the dispersibility of the seed polymer particles in the solvent and dispersion medium, polyvinyl alcohol, methyl cellulose, ethyl cellulose, which are known per se, can be used.
Polymer dispersion stabilizers such as polyacrylic acid, polyacrylimide, polyethylene oxide, poly(hydroxystearate-g-methyl methacrylate-co-methacrylic acid) copolymers, nonionic surfactants, and anionic interfaces. Active agents, cationic surfactants, amphoteric surfactants, etc. are used.

Among these, polymeric dispersion stabilizers such as polyvinyl alcohol are preferred and give good results when combined with an organic solvent-water mixture.

As the polymerization initiator, any oil-soluble one can be used.For example, as a radical polymerization initiator,
Soluble in monomers such as azo compounds such as azobisisobutyronitrile and peroxides such as cumene hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, di-L-butyl peroxide, benzoyl peroxide, and lauroyl peroxide. things are used. Furthermore, in the case of polymerization using ultraviolet rays, oil-soluble photopolymerization initiators among known photopolymerization initiators can be used. Among oil-soluble initiators, it is particularly desirable to use a polymerization initiator that is difficult to dissolve in an organic solvent so that the monomer is difficult to polymerize alone in an organic solvent.

According to the present invention, first, a monomer is dissolved in a water-miscible organic solvent or a mixture of this and water. The amount of monomer dissolved varies considerably depending on the type and composition of the solvent and monomer, but is generally 0. Ol to 50% by weight, especially 1 to 20
Weight % ranges are preferred.

This solution contains a core material or seed polymer particles, a dispersion stabilizer,
and a polymerization initiator. The amounts of nuclear material and seed polymer particles added vary depending on the desired particle size. That is, most of the monomers present in the system are distributed by the number of core materials or seed polymers, so that the monomers necessary to form particles of the desired particle size are distributed by the number of core materials or seed polymers. Coalescence - It is necessary to determine the amount of nuclear material and seed polymer added so that they are distributed per unit. In general, the ratio between the core material or seed polymer particles and the monomers in the system is from 1:1 to 1:109, especially 1:10.
Preferably, it is present in a weight ratio of 1:10' to 1:10';
On the other hand, the concentration of seed polymer particles in the dispersion is generally 0.
．． It is preferable to use it in a range of 0.1 to 50%, particularly 0.1 to 20%. Further, the dispersion stabilizer is preferably used in an amount of 0.1 to 30% by weight, particularly 1 to 10% by weight, based on the seed polymer particles, while the polymerization initiator is used in an amount of 0.001 to 10% by weight, based on the monomer charged. %, especially 0°01 to 0.
It is preferable to use it at 5% by weight.

Then, this dispersion system is once cooled to 0° C., and ice is added while stirring to disperse it throughout the system. The ice to be added preferably has a small particle size and a large contact area with the dispersion system.

The particle size is generally 0.01 to 10 mm, especially 0.1 to 10 mm.
It is mm. Further, the amount of ice added to the dispersion system can be selected as appropriate.

Then, when the dispersion system in which water is dispersed is heated to gradually melt the ice, the increase in the concentration of water in the entire dispersion system becomes approximately equal. In addition, by adjusting the amount of heat during this heating to change the dissolution rate, fine control of the particle size of the growing particles can be performed.

The amount of heat to be heated can be appropriately selected depending on the amount of the core, seed polymer particles, and monomer, but the capacity of the dispersion system should be 100 mI! , the amount of ice melted is generally 0.1 to 100 mj27
It is preferable to apply a heating amount of min, particularly 5 to 50 mff1/min.

Then, the monomers absorbed into the polymer particles or the monomers in the oil droplets formed around the core material are polymerized. Polymerization is generally carried out in an inert atmosphere such as nitrogen at temperatures between -30°C and 90°C.
It is carried out at a temperature of 1°C, in particular 30°C to 80°C. Polymerization conditions vary depending on the type of polymerization initiator; for example, if a photopolymerization initiator is used, light of an appropriate wavelength may be irradiated. If the polymerization initiator is one that reacts at low temperatures, monomer polymerization may begin at the same time as absorption into the seed polymer, but it is better to start polymerization after absorption is complete. This is more desirable because there is no risk of polymerizing on its own to form particles with a small diameter.

The polymerization time is such that the polymerization of the absorbed monomer is completed, and a suitable time is generally 0.1 to 30 hours. The method of the present invention may be carried out in only one stage, or may be carried out in multiple stages until the grains are grown to a predetermined size. The resulting polymer generally has a particle size of 1 to 1000 μm, especially 5 to 1 μm.
00 μm, and is characterized by being highly monodisperse. The obtained polymer particles can be used for various purposes in the form of a suspension, or can be separated by filtration.
After washing with water if necessary, it can be used in powder form for various purposes.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

(Example 1) 20 parts of styrene, 36 parts of ion exchange water, 14 parts of ethanol
A mixed solution of 284 cm of azobisisobutyronitrile and 2 g of polyacrylic acid was placed in a 3-necked separable flask equipped with a reflux device, and reacted at 70°C for 12 hours while stirring at 1100 rpm under a nitrogen stream. , the polymerization was completed. When the polymer was observed with an optical microscope, it was found to be monodisperse particles of about 2 μm. Polymer 4 synthesized in this way
700 g of ethanol and 700 g of ion exchange water.

30g of styrene, 15g of polyvinyl alcohol and 2.
2°-azobis(2,4-dimethylvaleronitrile) 1
An emulsion was obtained by dispersing it in 5 g of solution.

The emulsion obtained above was cooled to O'C, transferred to a thermos flask, and 1 kg of crushed ice was added without stirring until the particle size became about 1 mm or less. Put an electric heater into this thermos flask and 8
Heat was applied at a rate of 0.00 cal/min. When the emulsion was observed under an optical microscope, the particle size was approximately 8 μm.
It was swollen to m.

Next, transfer the emulsion to a reflux device. Place in a separable flask and heat at 1100 rpm under nitrogen flow.
The reaction was carried out at 70° C. for 8 hours while stirring to complete the polymerization. After filtering the obtained polymer, it is dried to about 28
g of resin particles were obtained.

The particle size distribution of the obtained particles was measured using a Coulter counter, and as shown in Table 1, they were extremely monodisperse and spherical particles with an average particle diameter of 7.6 μm.

Table 1 (Example 2) Styrene 14, butyl acrylate 6d, ion-exchanged water 36d, ethanol 144#f, azobisisobutyronitrile 280cm, and polyacrylic acid 2g were mixed in a 300d container equipped with a reflux device. The mixture was placed in a separate parallel flask and reacted at 70° C. for 12 hours while stirring at 1100 rpm under a nitrogen stream to complete polymerization. When the polymer was observed under an optical microscope, it was found to be monodisperse particles of about 2 μm.

An emulsion was obtained by dispersing 4 g of the polymer obtained above in a solution consisting of 700 g of methanol, 700 g of ion-exchanged water, 150 g of styrene, 3 g of polyvinyl alcohol, and 15 g of benzoyl peroxide.

The concentration of water in the emulsion obtained above was increased using the same operations and conditions as in Example 1.

When the emulsion at this time was observed with an optical microscope, the particles were swollen to 14 μm.

Then, the emulsion was placed in a 31-meter rose variable flask equipped with a reflux device and heated at 1100 rpm under a nitrogen stream.
The reaction was carried out at 70° C. for 8 hours while stirring to complete the polymerization. After filtering the obtained polymer, it is dried and
0 g of resin particles were obtained.

The particle size distribution of the obtained particles was measured using a Coulter counter, and as shown in Table 2, they were extremely monodisperse and spherical particles with an average particle diameter of 13.4 μm.

(1-A”F, multiplied &) (Example 3) 201 d of styrene, 36 d of ion exchange water, 1 d of ethanol
44d, 2,2°-azobisisobutyronitrile 284
■ A solution of 4 g of polyacrylic acid was heated to a
The polymerization was completed in the same manner as in Example 1. When the polymer was observed with an optical microscope, it was found to be monodisperse polymer particles of about 1 μm.

4 g of the polymer obtained above, 350 g of ethanol, 600 g of ion-exchanged water, 400 g of methyl methacrylate, 30 g of oil-soluble dye (C, I, Solvent Red 27),
2.2'-(2,4-azobisisobutyronitrile)
An emulsion was obtained by dispersing it in a solution consisting of Log.

The concentration of water in the emulsion obtained above was increased using the same operations and conditions as in Example 1. When the emulsion was observed under an optical microscope, the particles were 10 μm in size.
It was swollen.

Then, the emulsion was placed in a 31-inch parallel flask equipped with a reflux device and heated at 1100 rpm under a nitrogen stream.
The reaction was carried out at 70° C. for 8 hours with stirring to complete the polymerization. The obtained polymer was filtered and dried to obtain about 400 g of red resin particles.

The obtained particles are true spherical red particles, and the particle size distribution is extremely monodisperse as shown in Table 3, with an average particle size of 9.4.
They were spherical particles of μm in size.

Table 3 (Example 4) Average particle size 20 nm (7) IJ ly (AE
1 mg of RO3IL130 (manufactured by Nippon Aerosil Co., Ltd.) was dispersed in distilled water 11. Propyl alcohol 600ml from which particles insoluble in water and alcohol have been completely removed by distillation or ultrafiltration! , water 700mj! , methyl methacrylate 40g, polyvinylpyrrolidone 1°5
0.3 ml of the above silica suspension was added to a solution consisting of 1.5 g of benzoyl peroxide.

The suspension obtained above was operated in the same manner as in Example 1 and the concentration of water was increased. When this was observed with an optical microscope, droplets with a particle size of about 10 μm were formed.

Next, the emulsion was placed in a 32-inch separable flask equipped with a reflux device and heated at 1100 rpm under a nitrogen stream.
The reaction was carried out at 70° C. for 8 hours while stirring at 50° C. to complete the polymerization. After filtering the obtained polymer, it is dried and
0 g of resin particles were obtained.

The particle size distribution of the obtained particles was measured using a Coulter counter, and as shown in Table 4, the particles were highly monodisperse and spherical with an average particle diameter of 10.1 μm.

(Example 4) Silica [8 ERO5IL 130 (
Img (manufactured by Nippon Aerosil Co., Ltd.) was dispersed in distilled water 11. 600mf of isopropyl alcohol from which particles insoluble in water and alcohol have been completely removed by distillation or ultrafiltration, 700ml of water, 40ml of methyl methacrylate
A suspension of the above silica was added to a solution consisting of g, 1.5 g of polyvinylpyrrolidone, and 1.5 g of benzoyl peroxide.
．． 3rne was added.

The concentration of water was increased using the same operations and conditions as in Example 1 for the above-obtained Susbenzin. When this was observed with an optical microscope, droplets with a particle size of 10 μm were formed.

Next, polymer particles 40 were formed by the same operation as in the above example.
I got g. The particle size distribution of the obtained particles was measured using a Coulter counter, and the results shown in Table 4 were obtained.

(t-zT, margin) Table 4 (Example 5) 3 g of spherical ferrite particles with an average particle size of 5 μm and the particle size shown in Table 5 (1) were dissolved in 0.1 g of sodium dodecylbenzenesulfonate. The mixture was dispersed in 100 g of distilled water using a ball mill.

Excess surfactant in this suspension was removed by dialysis, and distilled water was added to bring the total amount to 700 g. Further, 700 g of ethanol, 30 g of styrene monomer, 1.5 g of polyvinyl alcohol, and 1.5 g of azobis(2,4-dimethylvaleronitrile) were dissolved in this suspension to obtain a suspension.

The suspension obtained above was subjected to the same operations and conditions as in Example 1 to increase the concentration of water.

When this was observed with an optical microscope, droplets containing one ferrite particle were formed.

Next, the emulsion was placed in a three-necked separable flask equipped with a reflux device, and heated at 10,100 rpm under a nitrogen stream.
The reaction was carried out at 70° C. for 8 hours with stirring to complete the polymerization. After filtering the obtained polymer, it is dried to give about 30g.
magnetic resin particles were obtained.

The particle size distribution of the obtained magnetic particles was measured using a Coulter counter, and as shown in Table 5 (2), they were extremely monodisperse, with an average particle size of 10 μm.

They were spherical particles of 5 μm.

(1: Margin) Table 5 4 g of phthalocyanine green with an average particle size of 5 μm and having the particle size distribution shown in Table 6 (1) was added to 100 g of distilled water in which 0.8 g of sodium lauryl sulfate was dissolved using a ball mill. Dispersed. Excess surfactant in this suspension was removed by dialysis, and distilled water was further added to bring the total amount to 700 g. Next, 700 g of methanol, 30 g of methyl acrylate, 1.5 g of polyvinyl alcohol, and 1.5 g of benzoyl peroxide were dissolved in this subenzidine.

The suspension obtained above was subjected to the same operations and conditions as in Example 1 to increase the concentration of water.

When this was observed with an optical microscope, the particle size was approximately 10 μm.
Droplets containing one green pigment were formed.

Next, the emulsion was placed in a three-necked separable flask equipped with a reflux device and heated at 1100 rpm''' under a nitrogen stream.
The reaction was carried out at 70° C. for 8 hours without stirring to complete the polymerization. After filtering the obtained polymer, it is dried for about 30 minutes.
g of green resin particles were obtained.

The particle size distribution of the obtained green particles was measured using a Coulter counter, and as shown in Table 6 (2), they were extremely monodisperse and spherical particles with an average particle size of 10.degree. 5 .mu.m.

Table-6 (2) You can do that.

Claims (2)

[Claims] (1) A water-miscible organic solvent that dissolves the monomer but does not dissolve the polymer or a mixture of the water-miscible organic solvent and water is used as the solvent, and the monomer, the core substance, the dispersion stabilizer, and an oil-soluble polymerization initiator are dissolved or dispersed in the above solvent, the dispersion system is cooled to 0°C, ice is added while stirring to disperse the system, and the dispersion system is heated to dissolve or disperse the dispersion system. By melting the ice, the concentration of water in the dispersion system is increased to form oil droplet particles consisting of oil-soluble substances such as monomers centered on a core substance and a polymerization initiator, and in the oil droplet particles. A method for producing monodisperse polymer particles, which comprises selectively polymerizing monomers. (2) Using a water-miscible organic solvent that dissolves the monomer but does not dissolve the polymer, or a mixture of the water-miscible organic solvent and water as a solvent, seed polymer particles exhibiting swelling properties;
The dispersion stabilizer and the oil-soluble polymerization initiator are dissolved or dispersed in the solvent, the dispersion system is cooled to 0°C, ice is added while stirring, and the dispersion system is heated. increasing the concentration of water in the dispersion to absorb monomer and polymerization initiator into the seed polymer particles by melting the ice in the dispersion; 1. A method for producing monodisperse polymer particles, which comprises selectively polymerizing particles.