JP2008239935A - Method for producing monodisperse minute particles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide resin particles having a sharp particle diameter distribution in which a hydrophilic component having various adverse influences on performances does not remain in the resin particles, or on the surface thereof, and the hydrophobicity is high, and which is excellent in electrical property and powder characteristic. <P>SOLUTION: The method for producing monodisperse resin particles (B) comprises: dispersing a dispersed phase (DP) consisting of a vinyl monomer (A) or an organic solvent solution of this monomer (A) in a continuous phase (CP) through a micro-channel (M); and performing a polymerization reaction and the elimination of this organic solvent, to produce resin particles (B), wherein this continuous phase (CP) is carbon dioxide of a supercritical state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to monodispersed vinyl resin particles having a uniform particle diameter and a method for producing the same. More specifically, the present invention relates to a method for producing vinyl resin particles that are dispersed in carbon dioxide in a supercritical state via a microchannel.

Conventionally, as a method for producing vinyl resin fine particles, an emulsion polymerization method, a suspension polymerization method, a seed polymerization method, and the like are known. The emulsion polymerization method is a method of synthesizing fine particles by performing a polymerization reaction in a surfactant micelle, and the suspension polymerization method is a method of synthesizing fine particles by polymerizing the dispersed phase of an emulsion, and a seed polymerization method Is a method of enlarging the particles after synthesizing the seed particles (see, for example, Patent Document 1).
Also known is a method of obtaining highly monodisperse vinyl resin particles by dispersing a vinyl reactive monomer in water through a microchannel to produce droplets and then performing a polymerization reaction ( For example, see Patent Document 2).
However, in the above two methods, a surfactant having a hydrophilic group (surfactant, polymer protection) is used for the purpose of reducing the free energy of the interface in water at the time of production or imparting dispersion stability in water. Colloids, surface active particles, etc.) must be used.
However, when these surface active substances remain in the resin particles or on the particle surface, they contain water-soluble impurities such as surfactants having hydrophilic groups, so that the powder characteristics, electrical characteristics, thermal properties of the resin particles There is a drawback that it adversely affects performance such as characteristics and chemical stability.
JP-A-5-222204 JP2001-181309

An object of the present invention is to obtain resin particles in which hydrophilic components that have various adverse effects on performance do not remain in or on the resin particles and the particle size distribution is sharp.

As a result of intensive studies to solve these problems, the present inventors have reached the present invention.
That is, by using carbon dioxide in a supercritical state as a continuous phase (CP), highly monodispersed resin particles without using a surfactant having a hydrophilic group, a polymer protective colloid, surfactant fine particles, etc. Found that you can get.

The resin particles obtained by the production method of the present invention are resin particles that do not contain a surfactant having a hydrophilic group and have a sharp particle size distribution. For this reason, monodisperse resin particles having high hydrophobicity and excellent electrical characteristics and powder characteristics can be obtained.

The present invention is a production method capable of obtaining monodisperse resin particles having a very uniform particle diameter using a microchannel (M).
That is, a dispersed phase (DP) containing a vinyl monomer (A) is dispersed in a continuous phase (CP) composed of carbon dioxide in a supercritical state via a microchannel (M), and the vinyl monomer (A) By polymerizing, monodispersed resin particles (B) can be produced.

The vinyl monomers used in the present invention include the following (1) to (10). Further, these vinyl monomers may be polymerized alone or may be copolymerized with other copolymerizable vinyl monomers.
(1) Vinyl hydrocarbons:
(1-1) Aliphatic vinyl hydrocarbons: alkenes such as ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, α-olefins other than the above, etc .; alkadienes such as butadiene , Isoprene, 1,4-pentadiene, 1,6-hexadiene, 1,7-octadiene and the like.
(1-2) Alicyclic vinyl hydrocarbons: mono- or di-cycloalkenes and alkadienes such as cyclohexene, (di) cyclopentadiene, vinylcyclohexene, ethylidenebicycloheptene and the like; terpenes such as pinene, limonene, Inden etc.
(1-3) Aromatic vinyl hydrocarbons: Styrene and its hydrocarbyl (alkyl, cycloalkyl, aralkyl and / or alkenyl) substitutes such as α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethyl Styrene, isopropyl styrene, butyl styrene, phenyl styrene, cyclohexyl styrene, benzyl styrene, crotyl benzene, divinyl benzene, divinyl toluene, divinyl xylene, trivinyl benzene, etc .; and vinyl naphthalene.

(2) Carboxyl group-containing vinyl monomers and their salts:
C3-C30 unsaturated monocarboxylic acids, unsaturated dicarboxylic acids and anhydrides thereof and monoalkyl (C1-24) esters thereof such as (meth) acrylic acid, (anhydrous) maleic acid, monoalkyl maleate Carboxyl group-containing vinyl monomers such as esters, fumaric acid, fumaric acid monoalkyl esters, crotonic acid, itaconic acid, itaconic acid monoalkyl esters, itaconic acid glycol monoether, citraconic acid, citraconic acid monoalkyl esters, and cinnamic acid.

(3) Sulfonic group-containing vinyl monomers, vinyl sulfate monoesters and their salts:
Alkene sulfonic acids having 2 to 14 carbon atoms such as vinyl sulfonic acid, (meth) allyl sulfonic acid, methyl vinyl sulfonic acid, styrene sulfonic acid; and alkyl derivatives having 2 to 24 carbon atoms such as α-methyl styrene sulfonic acid Sulfo (hydroxy) alkyl- (meth) acrylate or (meth) acrylamide, such as sulfopropyl (meth) acrylate, 2-hydroxy-3- (meth) acryloxypropylsulfonic acid, 2- (meth) acryloylamino-2 , 2-dimethylethanesulfonic acid, 2- (meth) acryloyloxyethanesulfonic acid, 3- (meth) acryloyloxy-2-hydroxypropanesulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, 3- (Meth) acrylamide-2- Droxypropanesulfonic acid, alkyl (C3-18) allylsulfosuccinic acid, poly (n = 2-30) oxyalkylene (ethylene, propylene, butylene: single, random or block) sulfuric acid of mono (meth) acrylate Esters [poly (n = 5 to 15) oxypropylene monomethacrylate sulfate ester, etc.], polyoxyethylene polycyclic phenyl ether sulfate ester, sulfate ester or sulfonic acid group-containing monomer, and salts thereof.

(4) Phosphoric acid group-containing vinyl monomers and salts thereof:
(Meth) acryloyloxyalkyl (C1 to C24) phosphoric acid monoester, for example, 2-hydroxyethyl (meth) acryloyl phosphate, phenyl-2-acryloyloxyethyl phosphate, (meth) acryloyloxyalkyl (C1-24) Phosphonic acids such as 2-acryloyloxyethylphosphonic acid.
Examples of the salts (2) to (4) include alkali metal salts (sodium salts, potassium salts, etc.), alkaline earth metal salts (calcium salts, magnesium salts, etc.), ammonium salts, amine salts, or quaternary grades. An ammonium salt is mentioned.

(5) Hydroxyl group-containing vinyl monomer:
Hydroxystyrene, N-methylol (meth) acrylamide, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, (meth) allyl alcohol, crotyl alcohol, isocrotyl alcohol, 1- Buten-3-ol, 2-buten-1-ol, 2-butene-1,4-diol, propargyl alcohol, 2-hydroxyethylpropenyl ether, sucrose allyl ether, and the like.

(6) Nitrogen-containing vinyl monomer:
(6-1) Amino group-containing vinyl monomer:
Aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, t-butylaminoethyl methacrylate, N-aminoethyl (meth) acrylamide, (meth) allylamine, morpholinoethyl (meth) acrylate, 4-vinylpyridine, 2-vinylpyridine, crotylamine, N, N-dimethylaminostyrene, methyl α-acetaminoacrylate, vinylimidazole, N-vinylpyrrole, N-vinylthiopyrrolidone, N-arylphenylenediamine, aminocarbazole, aminothiazole, amino Indole, aminopyrrole, aminoimidazole, aminomercaptothiazole, and salts thereof.
(6-2) Amide group-containing vinyl monomers: (meth) acrylamide, N-methyl (meth) acrylamide, N-butyl acrylamide, diacetone acrylamide, N-methylol (meth) acrylamide, N, N′-methylene-bis (Meth) acrylamide, cinnamic amide, N, N-dimethylacrylamide, N, N-dibenzylacrylamide, methacrylformamide, N-methyl N-vinylacetamide, N-vinylpyrrolidone and the like.
(6-3) Nitrile group-containing vinyl monomers: (meth) acrylonitrile, cyanostyrene, cyanoacrylate and the like.
(6-4) Quaternary ammonium cationic group-containing vinyl monomers: tertiary such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, diallylamine and the like Quaternized products of amine group-containing vinyl monomers (quaternized with a quaternizing agent such as methyl chloride, dimethyl sulfate, benzyl chloride, dimethyl carbonate).
(6-5) Nitro group-containing vinyl monomers: nitrostyrene and the like.

(7) Epoxy group-containing vinyl monomers: glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, p-vinylphenylphenyl oxide and the like.

(8) Halogen element-containing vinyl monomers: vinyl chloride, vinyl bromide, vinylidene chloride, allyl chloride, chlorostyrene, bromostyrene, dichlorostyrene, chloromethylstyrene, tetrafluorostyrene, chloroprene and the like.

(9) Vinyl esters, vinyl (thio) ethers, vinyl ketones, vinyl sulfones:
(9-1) Vinyl esters such as vinyl acetate, vinyl butyrate, vinyl propionate, vinyl butyrate, diallyl phthalate, diallyl adipate, isopropenyl acetate, vinyl methacrylate, methyl 4-vinylbenzoate, cyclohexyl methacrylate, benzyl methacrylate, phenyl ( (Meth) acrylate, vinyl methoxyacetate, vinyl benzoate, ethyl α-ethoxy acrylate, alkyl (meth) acrylate having 1 to 50 carbon atoms [methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate , Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadec (Meth) acrylate, eicosyl (meth) acrylate, etc.], dialkyl fumarate (two alkyl groups are straight, branched or alicyclic groups having 2 to 8 carbon atoms), dialkyl maleate (Two alkyl groups are linear, branched or alicyclic groups having 2 to 8 carbon atoms), poly (meth) allyloxyalkanes [diallyloxyethane, triaryloxyethane, Tetraallyloxyethane, tetraallyloxypropane, tetraallyloxybutane, tetrametaallyloxyethane, etc.] vinyl monomers having a polyalkylene glycol chain [polyethylene glycol (molecular weight 300) mono (meth) acrylate, polypropylene glycol (molecular weight 500) Monoacrylate, methyl alcohol ethylene oxide 10 mol adduct (meta ) Acrylate, lauryl alcohol ethylene oxide 30 mole adduct (meth) acrylate, etc.], poly (meth) acrylates [poly (meth) acrylate of polyhydric alcohols: ethylene glycol di (meth) acrylate, propylene glycol di (meth) Acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, polyethylene glycol di (meth) acrylate, etc.].

(9-2) Vinyl (thio) ether, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether, vinyl 2-ethylhexyl ether, vinyl phenyl ether, vinyl 2-methoxyethyl ether, methoxy butadiene, vinyl 2- Butoxyethyl ether, 3,4-dihydro1,2-pyran, 2-butoxy-2′-vinyloxydiethyl ether, vinyl 2-ethylmercaptoethyl ether, acetoxystyrene, phenoxystyrene, (9-3) vinyl ketones such as vinyl Methyl ketone, vinyl ethyl ketone, vinyl phenyl ketone; vinyl sulfone, such as divinyl sulfide, p-vinyl diphenyl sulfide, vinyl ethyl sulfide, vinyl ethyl sulfone, divinyl Rufon, such as divinyl Gandolfo key side.

(10) Other vinyl monomers:
Isocyanatoethyl (meth) acrylate, m-isopropenyl-α, α-dimethylbenzyl isocyanate and the like.

Examples of the copolymer of vinyl monomers include polymers obtained by copolymerizing any of the above-mentioned (1) to (10) with a binary or combination thereof in an arbitrary ratio.
For example, styrene- (meth) acrylic acid ester copolymer, styrene-butadiene copolymer, (meth) acrylic acid-acrylic acid ester copolymer, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, Styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic acid, divinylbenzene copolymer, styrene-styrenesulfonic acid- (meth) acrylic acid ester copolymer, and the like.

The volume average particle size of the monodispersed resin particles (B) of the present invention is preferably 0.01 to 50 μm, more preferably 0.01 to 30 μm from the viewpoint of sharpening the particle size distribution.
The volume average particle diameter can be measured with a particle size distribution measuring apparatus based on the Coulter principle.

In the particle size distribution of the monodispersed resin particles (B) of the present invention, the variation coefficient of the particle size is preferably 0.1 to 10%, more preferably 0.1 to 5%, particularly preferably 0.1 to 3. %.
Here, the variation coefficient is a value calculated from the following calculation formula.
Coefficient of variation = (standard deviation / volume average particle size) × 100

  Examples of the organic solvent (U) for dissolving the vinyl monomer (A) include aromatic hydrocarbon solvents such as toluene, xylene, ethylbenzene, and tetralin; aliphatics such as n-hexane, n-heptane, mineral spirit, and cyclohexane; Alicyclic hydrocarbon solvents: halogen solvents such as methyl chloride, methyl bromide, methyl iodide, methylene dichloride, carbon tetrachloride, trichloroethylene, perchloroethylene; ethyl acetate, butyl acetate, methyl propionate, ethyl propionate , Ester solvents such as methoxybutyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, etc .; diethyl ether, tetrahydrofuran, dioxane, ethyl cellosolve, butyl cellosolve, propylene glycol monomer Ether solvents such as ether; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-butyl ketone and cyclohexanone; methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, 2 -Alcohol solvents such as ethylhexyl alcohol and benzyl alcohol; amide solvents such as formamide, dimethylformamide and dimethylacetamide; sulfoxide solvents such as dimethyl sulfoxide; heterocyclic compounds solvents such as N-methylpyrrolidone; The mixed solvent of seed | species or more is mentioned.

In order to stably disperse the vinyl monomer (A) or the solvent solution thereof in the supercritical carbon dioxide (X), it is preferable to use a hydrophobic dispersion stabilizer (C).
As such a dispersion stabilizer (C), it has a dimethylsiloxane group having an affinity for carbon dioxide and at least one functional group of a fluorine-containing group, and has a weight average molecular weight of 1,000 to 1,000,000. A high molecular compound is mentioned.
That is, a polymer compound having a functional group containing a fluorine atom and / or a dimethylsiloxane group in the molecule and having a weight average molecular weight of 1,000 to 1,000,000 is preferable.
Furthermore, a comb polymer having a weight average molecular weight of 1,000 to 1,000,000 in which a functional group containing a fluorine atom and / or a dimethylsiloxane group is bonded to a side chain in the molecule is hydrophobic. More preferable as a dispersion stabilizer.
Specifically, a copolymer of at least one monomer having a dimethylsiloxane group or a fluorine-containing monomer and a vinyl monomer or oligomer is preferable. The form of copolymerization may be random, block or graft, but block or graft is preferred.
The dispersion stabilizer (C) may be added to either the continuous phase (CP) or the dispersed phase (DP).

In the resin of the present invention, other additives (pigments, fillers, antistatic agents, colorants, mold release agents, charge control agents, ultraviolet absorbers, antioxidants, antiblocking agents, heat stabilizers, flame retardants Etc.) may be contained.
As this method, it is preferable that an additive is mixed with a vinyl monomer or a solvent solution thereof to form a dispersed phase (DP) and then dispersed in a continuous phase (CP).

The microchannel (M) has a structure in which a dispersed phase and a continuous phase are separated by a partition having a through hole (flow channel), and the dispersed phase is pushed into the continuous phase through the through hole (flow channel). If it exists, it will not specifically limit, A well-known thing (For example, the microchannel as described in Unexamined-Japanese-Patent No. 2000-15070 or Unexamined-Japanese-Patent No. 2006-110505 is mentioned.) Can be used. The dispersed phase extruded through the microchannel becomes droplets and is dispersed in the continuous phase.

It is known that the surface of the microchannel is preferably compatible with the continuous phase. Since the supercritical carbon dioxide used for the continuous phase in the present invention is hydrophobic, the microchannel may be hydrophobized. The method of hydrophobizing is not particularly limited, but if the material of the microchannel is glass or silicon, for example, treatment with a silane coupling agent may be mentioned. Specifically, it may be hydrophobized by a known method using a silane coupling agent such as octyltriethoxysilane, octadecyltrichlorosilane, hexamethyldisilazane and the like.

  In the present invention, carbon dioxide (X) in a supercritical state is used as a solvent for the continuous phase (CP). Carbon dioxide in a supercritical state represents carbon dioxide existing under temperature and pressure conditions above the critical point (temperature = 31 ° C., pressure = 7.4 MPa).

The pressure of the continuous phase (CP) is preferably 7.4 MPa or higher in order to satisfactorily disperse the dispersed phase (DP) in the supercritical carbon dioxide (X), which is preferable from the viewpoint of equipment cost and operation cost. Is 40 MPa or less. More preferably, it is 7.5-35 MPa, More preferably, it is 8-30 MPa, Most preferably, it is 8.5-25 MPa, Most preferably, it is 9-20 MPa.
The temperature and pressure of (CP) are set so that the vinyl monomer (A) does not dissolve in the supercritical carbon dioxide (X) and the droplets containing the vinyl monomer (A) do not coalesce. It is preferable to do. Usually, the lower the temperature and the lower the pressure, the more the vinyl monomer (A) tends to not dissolve in the supercritical carbon dioxide (X), and the higher the temperature and the higher the pressure, the droplets containing the vinyl monomer (A) are united. It tends to be easy.

  In order to adjust the physical property values (viscosity, diffusion coefficient, dielectric constant, solubility, interfacial tension, etc.) as the continuous phase, other gases may be appropriately contained in the continuous phase (CP). For example, nitrogen, helium, argon, An inert gas such as air can be mentioned.

The viscosity of the dispersed phase (DP) is preferably 1 to 5000 mPa · s (measured by a B-type viscometer, measurement temperature 25 ° C.), more preferably 10 to 1000 mPa · s, from the viewpoint of particle size uniformity.
When the viscosity of the dispersed phase (DP) is high, it is preferable to mix with the organic solvent (U) described above, or to reduce the viscosity to the above preferred range by increasing the temperature.

The temperature of the dispersed phase (DP) is preferably 30 ° C. or higher in order to prevent carbon dioxide from undergoing a phase transition in the pipe during decompression and block the flow path, and thermal degradation of the resin particles (B). In order to prevent this, 200 ° C. or lower is preferable. Furthermore, 30-150 degreeC is preferable, More preferably, it is 34-130 degreeC, Especially preferably, it is 35-100 degreeC, Most preferably, it is 40-80 degreeC.
The difference between the temperature of the dispersed phase (DP) and the temperature of the continuous phase (CP) is not particularly limited, but a smaller one is preferable.

A method for polymerizing the vinyl monomer (A) in the vinyl monomer (A) or a solvent solution thereof dispersed in carbon dioxide (X) in a supercritical state is not particularly limited.
For example, it is preferable to obtain a resin particle (B) by mixing and dispersing a polymerization initiator immediately before dispersing the vinyl monomer (A) or a solvent solution thereof in (X) and simultaneously dispersing the polymerization initiator.
By the polymerization reaction, a dispersion (Y) in which the resin particles (B) are dispersed in carbon dioxide (X) in a supercritical state is obtained.
The reaction may be completed before depressurization, or may be allowed to react to some extent, and after depressurizing to take out (B), it may be completed by aging in a thermostatic bath or the like. Moreover, well-known catalysts, such as a transition metal catalyst, can be used as needed. The polymerization temperature is preferably 30 to 120 ° C, more preferably 40 to 100 ° C.

  When obtaining the resin particles (B) from the dispersion (Y) in which the resin particles (B) are dispersed in the supercritical carbon dioxide (X), the supercritical carbon dioxide is removed under reduced pressure. At this time, it is possible to reduce the pressure stepwise by providing multiple pressure-controlled containers in multiple stages, or to reduce the pressure to normal temperature and normal pressure at once.

When the resin particles (B) contain an organic solvent, it is desirable to remove the organic solvent. Examples of the method include a method in which hot air or steam is brought into contact with the resin particles (B), and a method in which an organic solvent is extracted from the resin particles (B) into a carbon dioxide phase.
An extraction method is preferable from the viewpoint that coalescence between the resin particles (B) hardly occurs. Further, an operation of extracting the organic solvent by replacing carbon dioxide containing the organic solvent with carbon dioxide containing no organic solvent is repeatedly performed. It is preferable.

The method for collecting the resin particles (B) is not particularly limited, and examples thereof include a method of collecting with a filter and a method of collecting with a cyclone.

  Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto. In the following description, “parts” represents parts by weight and “%” represents% by weight.

In the following examples, model WMS1 manufactured by EPTEC Co., Ltd. was used as the microchannel. The conceptual diagram is as shown in FIG.

Production Example 1 <Production of dispersion stabilizer solution>
In a reaction vessel equipped with a stirrer, 700 parts of tetrahydrofuran (THF) was charged, and the air in the reaction vessel was purged with nitrogen, followed by heating to reflux temperature. Next, 150 parts of methyl methacrylate, 150 parts of methacryl-modified silicone (functional group equivalent: 12,000 g / mol, number average molecular weight 12,000, manufactured by Shin-Etsu Chemical Co., Ltd .: X22-2426), azobisisobutyronitrile After 5 parts of the mixture was properly placed in the reaction vessel in 2 hours, it was aged at reflux temperature for 6 hours to obtain a dispersion stabilizer solution (C-1). The weight average molecular weight was 43,000.

Example 1
The microchannel (M) was installed at the dispersed phase introduction site in the dispersion tank T2. In the experimental apparatus of FIG. 2, first, the valves V1 and V2 were closed, carbon dioxide (purity 99.99%) was introduced into the particle recovery tank T3 from the cylinder B2 and the pump P3, and the pressure was adjusted to 10 MPa and 40 ° C. The solution tank T1 is charged with 150.0 parts of divinylbenzene mixed with 1% benzoyl peroxide and 40.0 parts of the dispersion stabilizer solution (C-1) obtained in Production Example 1, and dispersed by stirring and mixing. A phase solution (DP-1) was obtained.

Carbon dioxide was introduced into the dispersion tank T2 from the cylinder B1 and the pump P2, and adjusted to 15 MPa and 40 ° C. Thereafter, the dispersed phase solution (DP-1) was introduced into the dispersion tank T2 at 15 MPa through the microchannel from the tank T1 and the pump P1.

After introducing the dispersed phase solution (DP-1), the valve V1 was opened, carbon dioxide previously adjusted to 10 MPa and 40 ° C. was charged into the particle recovery tank T3, the dispersion was introduced therein, and the pressure became constant. By the way, V1 was closed. By this operation, the solvent THF was extracted and removed from the resin particles.

Next, while introducing supercritical carbon dioxide into the particle recovery tank T3 from the pressure cylinder B2 and the pump P3, the pressure is maintained at 10 MPa by the pressure regulating valve V2, thereby removing the carbon dioxide containing the extracted solvent. While discharging | emitting to trap tank T4, the resin particle was capture | acquired by the filter F1.
The introduction of carbon dioxide into the particle recovery tank T3 from the pressure cylinder B2 and the pump P3 means that carbon dioxide is introduced when 8 times the amount of carbon dioxide introduced into the dispersion tank T2 is introduced into the particle recovery tank T3. Stopped. At the time of this stop, the operation of replacing carbon dioxide containing the solvent with carbon dioxide containing no solvent and capturing the resin particles in the filter F1 was completed.
Further, the pressure regulating valve V2 was opened little by little, and the inside of the particle recovery tank was reduced to atmospheric pressure to remove carbon dioxide, and the vinyl resin particles (B-1) of the present invention supplemented by the filter F1 were obtained. .

Example 2
A vinyl resin particle (B-2) was obtained using a dispersed phase solution (DP-2) obtained by diluting divinylbenzene to 50% with toluene as the dispersed phase solution.

Comparative Example 1
Resin particles (B-3) for comparison were obtained using divinylbenzene in which benzoyl peroxide was dissolved as the dispersed phase and water in which 1% sodium dodecyl sulfate was dissolved in the continuous phase.

<Measurement of physical properties>
The resin particles (B-1) and (B-2) obtained in Examples 1 and 2 and the resin particles (B-3) obtained in Comparative Example 1 were dispersed in water, and the volume average particle diameter and volume basis were determined. The variation coefficient of the particle size distribution was measured with a particle size distribution meter (manufactured by Coulter Inc .; Multisizer III). The measurement results are shown in Table 1.

  As is apparent from Table 1, the resin particles obtained from the production method of the present invention have a very large variation coefficient of particle size distribution equivalent to that of the comparative example according to the prior art without using a surfactant having a hydrophilic group. Small monodisperse fine particles.

  Resin particles obtained from the production method of the present invention are paint additives, cosmetic additives, paper coating additives, slush molding resins, powder paints, electronic component manufacturing spacers, catalyst carriers, electrophotographics. Very useful as toners, electrostatic recording toners, electrostatic printing toners, standard particles for electronic measuring instruments, particles for electronic paper, medical diagnostic carriers, chromatographic fillers, particles for electrorheological fluids, and other resin particles for molding materials is there.

An example of the shape of the microchannel (M) used for producing the monodisperse resin particles of the present invention, and a perspective view of the dispersed phase, continuous phase, and droplets as seen from obliquely above and a front view seen from the front FIG. Through the through hole of the microchannel (M), the lower dispersed phase (DP) is pushed out toward the upper continuous phase (CP) (D1), and droplets are generated (D2). It is a flowchart of the experimental apparatus used for preparation of the monodispersed resin particle in this invention.

Explanation of symbols

CP: Continuous phase DP: Dispersed phase D1: Droplets being generated D2: Droplets generated M: Microchannel T1: Solution tank T2: Dispersion tank (maximum operating pressure 20 MPa, maximum operating temperature 200 ° C.)
T3: Particle recovery tank (maximum operating pressure 20 MPa, maximum operating temperature 100 ° C.)
T4: Solvent trap F1: Ceramic filter (mesh: 0.5 μm)
B1, B2: Carbon dioxide cylinder P1: Solution pump P2, P3: Carbon dioxide pump V1: Valve V2: Pressure adjustment valve

Claims (5)

A dispersed phase (DP) composed of the vinyl monomer (A) or an organic solvent solution of the monomer (A) is dispersed in the continuous phase (CP) through the microchannel (M), and the polymerization reaction and the organic solvent are mixed. A method for producing monodisperse resin particles (B), wherein the continuous phase (CP) is carbon dioxide in a supercritical state in the method for producing resin particles (B) by removing. The method for producing resin particles according to claim 1, wherein the coefficient of variation of the particle size distribution of the resin particles (B) is 0.1 to 10%. The method for producing resin particles according to claim 1 or 2, wherein the dispersed phase (DP) is dispersed in the continuous phase (CP) in the presence of the hydrophobic dispersion stabilizer (C). The hydrophobic dispersion stabilizer (C) is a polymer compound having a functional group containing a fluorine atom and / or a dimethylsiloxane group in the molecule and having a weight average molecular weight of 1,000 to 1,000,000. Item 4. The production method according to Item 3. The production according to claim 3 or 4, wherein the hydrophobic dispersion stabilizer (C) is a comb polymer compound in which a functional group containing a fluorine atom and / or a dimethylsiloxane group is bonded to a side chain in the molecule. Method.

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