JP2009256639A - Method for producing monodisperse polymer particles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymerization method, whereby polymer particles with a uniform grain size distribution can be prepared through the seed polymerization of hydrophobic monomer molecules. <P>SOLUTION: The method for producing mono dispersion polymer particles by seed polymerization comprises causing seed particles to absorb monomer molecules in an aqueous medium and then polymerizing the monomer molecules. Problems are solved by the method for producing mono dispersion polymer particles, wherein the monomers contain 5 wt.% or more of a hydrophobic vinylic monomer and 80 pts.wt or more of the monomers are absorbed by 1 pt.wt of the seed particles, and the aqueous medium contains a surfactant in an amount 9 to 24 times greater than critical micelle concentration. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing monodisperse polymer particles. More specifically, the present invention relates to a method for producing monodisperse polymer particles by a seed polymerization method.

  A seed polymerization method is known as a method for producing monodisperse polymer particles. The seed polymerization method is a method in which a monomer emulsion prepared in advance in an aqueous medium is absorbed with a monomer emulsion and polymerized. For example, as a seed polymerization method, there is a method described in JP-A-8-169907 (Patent Document 1). In this method, the concentration of the surfactant in the aqueous medium is adjusted to 1 to 6 times the critical micelle concentration, the aqueous medium is stirred, the seed particles absorb the monomer, and the polymerization starts to dissolve in the monomer. Monodisperse polymer particles are obtained by polymerizing the monomer in the seed particles in the presence of the agent.

JP-A-8-169907

  However, within the critical micelle concentration range described in the above publication, elution of the hydrophobic vinyl monomer into the aqueous medium is insufficient, and as a result, the residual vinyl monomer that is not absorbed into the seed particles There arises a problem that the body droplets are polymerized as they are and are mixed into the product as small particles and coarse particles. In particular, when the swelling ratio is increased in order to obtain large particles with good productivity, the above problem is remarkable. Therefore, even when a hydrophobic vinyl monomer is used in the seed polymerization method, it has been desired to provide a production method capable of giving polymer particles having higher monodispersibility with high productivity.

A method for producing monodisperse polymer particles by a seed polymerization method in which a monomer is absorbed in seed particles in an aqueous medium and then the monomer is polymerized,
The monomer contains 5% by weight or more of a hydrophobic vinyl monomer and is absorbed by the seed particles by 80 parts by weight or more with respect to 1 part by weight of the seed particles;
The method for producing monodisperse polymer particles, wherein the aqueous medium contains a surfactant in an amount of 9 to 24 times the critical micelle concentration.

According to the production method of the present invention, polymer particles having a uniform particle diameter with high productivity (high monodispersibility) can be obtained.
Furthermore, according to the production method of the present invention, when the particle diameter of the seed particles is 1, larger monodisperse polymer particles having a particle diameter of 4.5 or more can be obtained.
Furthermore, by using an anionic surfactant as the surfactant, the absorption of the monomer seed particles can be further promoted, so that polymer particles with high monodispersibility can be obtained.
Further, according to the production method of the present invention, small particles having a particle size of 2.2% or less in terms of volume or 25% or less in terms of number (particles having a particle size of 80% or less of the average particle size of monodisperse polymer particles) And high monodisperse polymer particles can be obtained.

FIG. 4 is a particle size distribution diagram expressed in number% of the polymer particles obtained in Example 1 and Comparative Example 1. 2 is an electron micrograph of polymer particles obtained in Example 1 and Comparative Example 1. FIG.

The present invention relates to a method for producing monodisperse polymer particles by a seed polymerization method in which a monomer is absorbed in seed particles in an aqueous medium and then the monomer is polymerized.
The monomer contains 5% by weight or more of a hydrophobic vinyl monomer. According to the method of the present invention, even when a hydrophobic vinyl monomer is contained in an amount of 5% by weight or more, the generation of small particles and coarse particles is suppressed, and highly monodisperse polymer particles are produced with high productivity. Obtainable. Further, even if the content of the hydrophobic vinyl monomer is 20% by weight or more, further 40% by weight or more, and further 60% by weight or more, the monodispersity High polymer particles can be obtained with high productivity. The upper limit of the content is 100% by weight.
In the present specification, hydrophobic means that the solubility in water at 25 ° C. is 1 g / L or less.

Examples of hydrophobic vinyl monomers include monofunctional styrenes such as styrene, p-methylstyrene, p-chlorostyrene, and α-methylstyrene, polyfunctional styrenes such as divinylbenzene, butyl acrylate, and acrylic acid 2 -Ethylhexyl, butyl methacrylate, trimethylolpropane triacrylate and the like. These monomers can be used alone or in combination of two or more.
Other monomers may be added to the hydrophobic vinyl monomer. Other monomers include monomers having a water solubility at 25 ° C. of greater than 1 g / L. The other monomer is used in an amount of 95% by weight or less based on the total monomer.

Other monomers include acrylic esters such as methyl acrylate, ethyl acrylate and diethylaminoethyl acrylate, methacrylic esters such as methyl methacrylate, ethyl methacrylate and diethylaminoethyl methacrylate, ethylene glycol mono (meth) Glycol esters of (meth) acrylic acid such as acrylate and polyethylene glycol mono (meth) acrylate, alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, vinyl esters such as vinyl acetate and vinyl butyrate, N-methylacrylamide, N- N-alkyl substituted (meth) acrylamides such as ethyl acrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, nitrile such as acrylonitrile, methacrylonitrile, etc. It can be used Le acids. Moreover, polyfunctional monomers, such as ethylene glycol di (meth) acrylate, can also be used by mixing with acrylic acid esters or methacrylic acid esters. These monomers can be used alone or in combination of two or more.
Preferred other monomers are methyl acrylate, ethyl acrylate, methyl methacrylate and ethyl methacrylate.
In the present specification, “(meth) acryl” means “acryl” or “methacryl”.

Examples of the aqueous medium include water and a mixed medium of water and a water-soluble solvent (for example, lower alcohol).
The aqueous medium contains a surfactant. As the surfactant, any of anionic, cationic, nonionic and zwitterionic compounds can be used.

  Examples of anionic surfactants include fatty acid oils such as sodium oleate and castor oil, alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalene sulfone. Acid salts, alkane sulfonates, dialkyl sulfosuccinates such as sodium dioctyl sulfosuccinate, alkenyl succinates (dipotassium salts), alkyl phosphate esters, naphthalene sulfonate formalin condensates, polyoxyethylene alkyl phenyl ether sulfates Examples thereof include salts, polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate, and polyoxyethylene alkyl sulfate salts.

Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.
Examples of zwitterionic surfactants include lauryl dimethylamine oxide and phosphate ester or phosphite ester surfactants.
You may use the said surfactant individually or in combination of 2 or more types. Of the above surfactants, anionic surfactants are preferred from the viewpoint of dispersion stability during polymerization.

In the present invention, the surfactant is used in an amount of 9 to 24 times the critical micelle concentration. The critical micelle concentration is a concentration at which the surfactant starts to form molecular aggregates called micelles in water. In the present specification, the critical micelle concentration is a value measured by the Wilhelmy method.
The reason why the surfactant content is 9 to 24 times the critical micelle concentration is less than 9 times the critical micelle concentration, and is occupied by small particles of 80% (80% diameter) or less of the average particle size. This is because the proportion may increase and the monodispersibility may decrease, and conversely if it is more than 24 times, the polymer particles may aggregate and monodisperse polymer particles may not be obtained. A more preferable content is 9 to 16 times the critical micelle concentration.

(Seed particles)
The seed particles that can be used in the present invention are not particularly limited, and examples thereof include vinyl resin particles such as acrylic particles and styrene particles.
Examples of the acrylic particles include particles derived from (meth) acrylic monomers. Examples of (meth) acrylic monomers include acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, dodecyl acrylate, stearyl acrylate, 2-acrylic acid 2- Ethylhexyl, tetrahydrofurfuryl acrylate, diethylaminoethyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, methacrylic acid Examples include dodecyl acid, 2-ethylhexyl methacrylate, stearyl methacrylate, and diethylaminoethyl methacrylate. These monomers may be used alone or in combination of two or more.

  Other monomers may be added to the acrylic monomer. Other monomers include glycol esters of (meth) acrylic acid such as ethylene glycol mono (meth) acrylate and polyethylene glycol mono (meth) acrylate, alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, vinyl acetate, butyric acid Vinyl esters such as vinyl; N-alkyl substituted (meth) acrylamides such as N-methylacrylamide, N-ethylacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide; nitriles such as acrylonitrile and methacrylonitrile; Polyfunctional monomers such as divinylbenzene, ethylene glycol di (meth) acrylate, trimethylolpropane triacrylate, styrene, p-methylstyrene, p-chlorostyrene, chloromethylstyrene, - it includes styrene monomers such as methylstyrene. These other monomers may be used alone or in combination of two or more.

  Examples of the styrene particles include particles derived from styrene monomers such as styrene, p-methylstyrene, p-chlorostyrene, chloromethylstyrene, and α-methylstyrene. These styrene monomers may be used alone or in combination of two or more.

  You may add another monomer to the said styrene-type monomer. Other monomers include glycol esters of (meth) acrylic acid such as ethylene glycol mono (meth) acrylate and polyethylene glycol mono (meth) acrylate, alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, vinyl acetate, butyric acid Vinyl esters such as vinyl; N-alkyl substituted (meth) acrylamides such as N-methylacrylamide, N-ethylacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide; nitriles such as acrylonitrile and methacrylonitrile; Polyfunctional monomers such as divinylbenzene, ethylene glycol di (meth) acrylate, trimethylolpropane triacrylate, acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic Isobutyl acrylate, t-butyl acrylate, dodecyl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, tetrahydrofurfuryl acrylate, diethylaminoethyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacryl (Meth) acrylic monomers such as n-butyl acid, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate and diethylaminoethyl methacrylate It is done. These other monomers may be used alone or in combination of two or more.

The average particle size of the seed particles can be appropriately adjusted depending on the conditions such as the amount of the vinyl monomer to be absorbed and the desired particle size of the monodisperse polymer particles.
When the seed particles are acrylic particles, the acrylic resin constituting the seed particles preferably has a weight average molecular weight of 10,000 to 40,000. If it is less than 10,000, it may be difficult to obtain polymer particles having excellent monodispersibility. In addition, phase separation may occur when the molecular structure of the seed particle and the absorbed monomer are different. In this case, as the polymerization proceeds, internal voids and cracks are generated, and the mechanical strength of the resulting monodisperse polymer particles may be significantly reduced. When it is larger than 40,000, the monomer absorption rate may decrease. A more preferred weight average molecular weight is 10,000 to 30,000.

When the seed particles are styrene particles, the weight average molecular weight of the styrene resin constituting the seed particles is preferably 10,000 to 40,000 for the same reason as the acrylic particles. A more preferred weight average molecular weight is 10,000 to 30,000.
The seed particles can be obtained by a known method such as an emulsion polymerization method or a suspension polymerization method.
The seed particles may be isolated from the polymerization system, or may be used as they are for the production of monodisperse polymer particles without isolation.

Here, from the viewpoint of suppressing the generation of small particles and coarse particles, the weight of the seed particles is adjusted so that the monodisperse polymer particles have a weight of 80 or more when the weight of the seed particles is 1. . The weight of the preferable monodisperse polymer particle is 100 to 300, and the more preferable weight is 100 to 250. Thus, even if the weight of the monodisperse polymer particles is increased with respect to the weight of the seed particles, highly monodisperse polymer particles can be obtained.
Further, from the same viewpoint as described above, the average particle size of the seed particles is adjusted so that the monodisperse polymer particles have a particle size of 4.5 or more when the particle size of the seed particles is 1. Is preferred.

The method of the present invention may be referred to a known seed polymerization method. A general method of the seed polymerization method will be described below, but is not limited to this method.
First, seed particles are added to an emulsion composed of a monomer and an aqueous medium. The emulsion can be prepared by a known method. For example, an emulsion can be obtained by adding a monomer to an aqueous medium and dispersing the monomer with a fine emulsifier such as a homogenizer, an ultrasonic processor, or a nanomizer. The monomer may contain a polymerization initiator as necessary. The polymerization initiator may be premixed with the monomer and then dispersed in an aqueous medium, or a mixture of both separately dispersed in an aqueous medium. The particle diameter of the monomer droplets in the obtained emulsion is preferably smaller than the seed particles because the polymerizable monomer is efficiently absorbed by the seed particles.
The seed particles may be added directly to the emulsion, or may be added in a form in which the seed particles are dispersed in an aqueous dispersion medium (hereinafter referred to as seed particle dispersion).

After the seed particles are added to the emulsion, the seed particles are allowed to absorb the monomer. This absorption can usually be performed by stirring the emulsion after addition of seed particles at room temperature (about 20 ° C.) for 1 to 12 hours. Moreover, you may accelerate | stimulate absorption by heating an emulsion to about 30-50 degreeC.
The seed particles swell due to the absorption of the monomer. The mixing ratio of the monomer and the seed particle is 80 parts by weight or more of the monomer with respect to 1 part by weight of the seed particle, and is preferably in the range of 100 to 300 parts by weight of the monomer, and 100 to 250 parts by weight. Part is more preferred. When the monomer mixing ratio decreases, the increase in particle diameter due to polymerization decreases, resulting in a decrease in productivity. May produce particles. The end of absorption can be determined by confirming the enlargement of the particle diameter by observation with an optical microscope.

  Examples of the polymerization initiator to be added as needed include benzoyl peroxide, lauroyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, and t-butyl peroxide. Organic peroxides such as oxy-2-ethylhexanoate and di-t-butyl peroxide; 2,2′-azobisisobutyronitrile, 1,1′-azobiscyclohexanecarbonitrile, 2,2 ′ -Azo compounds such as azobis (2,4-dimethylvaleronitrile). The polymerization initiator is preferably used in the range of 0.1 to 1.0 part by weight with respect to 100 parts by weight of the polymerizable monomer.

Next, the monomer absorbed in the seed particles is polymerized to obtain monodisperse polymer particles.
The polymerization temperature can be appropriately selected according to the type of monomer and polymerization initiator. The polymerization temperature is preferably 25 to 110 ° C, more preferably 50 to 100 ° C. The polymerization reaction is preferably carried out by raising the temperature after the monomer particles, and optionally the polymerization initiator, are completely absorbed by the seed particles. After completion of the polymerization, the monodisperse polymer particles are centrifuged as necessary to remove the aqueous medium, washed with water and a solvent, and then dried and isolated.

In the polymerization step, a polymer dispersion stabilizer may be added in order to improve the dispersion stability of the monodisperse polymer particles.
Examples of the polymer dispersion stabilizer include polyvinyl alcohol, polycarboxylic acid, celluloses (such as hydroxyethyl cellulose and carboxymethyl cellulose), and polyvinyl pyrrolidone. An inorganic water-soluble polymer compound such as sodium tripolyphosphate can also be used in combination. Of these, polyvinyl alcohol and polyvinyl pyrrolidone are preferable. The addition amount of the polymer dispersion stabilizer is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the monomer.
In order to suppress the generation of emulsified particles in an aqueous system, water-soluble polymerization inhibitors such as nitrites, sulfites, hydroquinones, ascorbic acids, water-soluble vitamin Bs, citric acid, and polyphenols may be used. Good.

According to the method of the present invention, the production of small particles and coarse particles derived from a vinyl monomer is suppressed, and polymer particles having good productivity and good monodispersibility can be obtained.
For example, a monodispersed polymer in which the amount of small particles having a particle size of 80% or less of the average particle size of monodispersed polymer particles is suppressed to 2.2% or less by volume or 25% or less by number. It becomes possible to obtain particles.
Further, the amount of coarse particles having a particle diameter of 120% or more of the average particle diameter of the monodisperse polymer particles is suppressed to 4.5% or less by volume or 2.0% or less by number. It becomes possible to obtain polymer particles.

  The monodisperse polymer particles obtained by the present invention can be used as a light diffusing agent. In addition to light diffusing agents, paints such as LCD spacers, silver salt film surface modifiers, magnetic tape film modifiers, thermal paper running stabilizers, etc., rheology control agents, matting agents, etc.・ Chemical field such as ink and adhesive, medical field such as antigen-antibody reaction test particle, cosmetic field such as slip agent and extender pigment, low shrinkage agent of resin such as unsaturated polyester, paper, dental material, anti It can be used in general industrial fields such as blocking agents, matting agents, and resin modifiers.

EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited by these Examples. In addition, the measuring method of a weight average molecular weight, an average particle diameter, and a variation coefficient is described below.
(Measurement of weight average molecular weight)
The weight average molecular weight is measured using gel permeation chromatography (GPC). The measuring method is as follows. In addition, a weight average molecular weight means a polystyrene (PS) conversion weight average molecular weight.
Measuring device: GPC HLC-8020 manufactured by Tosoh Corporation
Guard column: TOSOH TSK guard column HHR (S) x 1 (7.5 mm ID x 7.5 cm)
Column: TOSOH TSK-GEL GMHHR-H (S) × 3 (7.8 mm ID × 30 cm)
Measurement conditions: column temperature (40 ° C.), mobile phase (primary THF / 45 ° C.),
S. PUMP / R. PUMP flow rate (0.8 / 0.5 mL / min),
RI temperature (35 ° C), INLET temperature (35 ° C),
Measurement time (55 min), detector (UV254 nm, RI)
Measurement method: 50 mg of a sample is left standing overnight in 10 mL primary THF (mobile phase) and dissolved, and then filtered through a 0.45 μm or 0.20 μm filter.
Standard polystyrene for calibration curve: manufactured by Showa Denko KK, trade name “shodex”, weight average molecular weight: 1030000, manufactured by Tosoh Corporation, weight average molecular weight: 5480000, 3840000, 355000, 102000, 37900, 9100, 2630, 495

(Measurement of average particle size and coefficient of variation)
The average particle diameter is measured by performing calibration using a 50 μm aperture in accordance with Reference MANUAL FOR THE COULTER MULTISIZER (1987) published by Coulter Electronics Limited.
Specifically, 0.1 g of resin particles are predispersed in 10 ml of 0.1% nonionic surfactant using a touch mixer and ultrasonic waves, and this is provided with ISOTON II (Beckman Coulter, Inc .: electrolysis for measurement) provided in the main body. In a beaker filled with (Liquid), drop with a dropper while gently stirring, and adjust the reading of the densitometer on the main body screen to about 10%. Next, an aperture size of 50 μm, a current of 800, a gain of 4, and a polarity of + are input to the body of a Coulter Multisizer II (manufactured by Beckman Coulter, Inc .: measuring device) and measured manually. During the measurement, the beaker is gently stirred to the extent that bubbles do not enter, and the measurement ends when 100,000 resin particles are measured. The average value of volume weight (arithmetic average particle diameter in volume% mode: volume median diameter) is calculated as the average particle diameter (x) of the resin particles.
The coefficient of variation (Cv value) is a value calculated from the standard deviation (σ) and the average particle diameter (x) by the following formula.
Cv value (%) = (σ / x) × 100

Example 1
[Manufacture of seed particles]
First, 3000 g of ion-exchanged water, and then 500 g of ethyl methacrylate (EMA) in which 10 g of 1-octanethiol was dissolved as a molecular weight regulator were added, and the temperature was raised to 55 ° C. in a nitrogen stream while stirring. A monodisperse polyEMA having an average particle size of 0.5 μm and a weight average molecular weight of 13,000 is charged after 2.6 g of potassium persulfate is dissolved in 100 g of ion-exchanged water and stirred for 12 hours at 55 ° C. Dispersion (solid content 14.3%) was obtained.

  Next, a monomer mixture obtained by dissolving 5.5 g of 2,2′-azobisisobutyronitrile and 11 g of 1-octanethiol in 550 g of methyl methacrylate (MMA) was added to sodium dioctylsulfosuccinate. Mixed with 2200 g of ion-exchanged water containing 5 g; It was put into K homomixer Mark 2.5 type (made by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 5 minutes to obtain an emulsion.

  To this emulsion, 390 g of a seed particle dispersion (solid content: 14.3%) having an average particle size of 0.5 μm obtained above was added and stirred at room temperature for 3 hours. When the dispersion at that time was observed with an optical microscope, it was confirmed that the monomer in the emulsion was completely absorbed by the seed particles. To this dispersion was added 1100 g of a 3.6% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd., GH-17), followed by polymerization at 55 ° C. for 6 hours and then at 80 ° C. for 1.5 hours, and the average particle size was A dispersion liquid (solid content: 14.3%) of monodisperse polymethyl methacrylate having 1.50 μm and a weight average molecular weight of 16,000 was obtained.

[Production of monodisperse polymer particles]
First, 450 g of MMA, 180 g of styrene, 370 g of divinylbenzene, 6 g of 2,2′-azoisobutyronitrile and 6 g of benzoyl peroxide were dissolved in a monomer mixture, and 20 g of sodium dioctylsulfosuccinate (critical micelle concentration) (16 times as much as 0.125% by weight) is mixed with 1000 g of ion-exchanged water. The mixture was placed in K homomixer Mark 2.5 type (manufactured by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 10 minutes to obtain an emulsion.

  60 g of the seed particle dispersion (solid content: 14.3%) having an average particle diameter of 1.50 μm obtained above was added to this emulsion and stirred at 30 ° C. for 5 hours. To this dispersion was added 2000 g of a 4% aqueous solution of polyvinyl alcohol GH-17 and 0.6 g of sodium nitrite, and then the mixture was stirred at 60 ° C. for 5 hours and then at 105 ° C. for 2.5 hours to carry out a polymerization reaction.

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 8.0 μm, the coefficient of variation was 7.2%, and the particle size of 7.3 μm or less was 0.00 in the volume% distribution. 9%, 7.3-9.1 [mu] m is 96.6%, 9.1 [mu] m or more is 2.5%, 25% diameter is 7.6 [mu] m, 75% diameter is 8.1 [mu] m in the number% distribution, 80 Since the ratio of small particles having a% diameter (6.4 μm) or less is 1.13% in terms of volume and 16.6% in terms of number, it is recognized that the particles have very uniform particle diameters. It was.

Example 2
[Manufacture of seed particles]
First, 3000 g of ion-exchanged water, and then 500 g of MMA in which 10 g of 1-octanethiol was dissolved as a molecular weight regulator were added. The temperature was raised to 70 ° C. in a nitrogen stream while stirring, and 2.5 g of potassium persulfate as a polymerization initiator. Was dissolved in 100 g of ion-exchanged water and stirred for 12 hours at 70 ° C. to carry out a polymerization reaction. A dispersion of monodisperse polyMMA having an average particle size of 0.5 μm and a weight average molecular weight of 24,000 (solid content) 14.3%).

  Next, a monomer mixture obtained by dissolving 5 g of 2,2′-azobisisobutyronitrile and 5 g of 1-octanethiol in 200 g of MMA was mixed with 2000 g of ion-exchanged water containing 5 g of sodium dioctylsulfosuccinate. Mixed, T.W. It was put into K homomixer Mark 2.5 type (made by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 5 minutes to obtain an emulsion.

  140 g of the seed particle dispersion (solid content: 14.3%) having an average particle diameter of 0.5 μm obtained above was added to this emulsion, and the mixture was stirred at room temperature for 3 hours. When the dispersion at that time was observed with an optical microscope, it was confirmed that the monomer in the emulsion was completely absorbed by the seed particles. To this dispersion was added 1800 g of a 3.6% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd., GH-17), followed by polymerization at 70 ° C. for 6 hours, an average particle size of 1.00 μm, and a weight average molecular weight of 2. A dispersion of 30,000 monodispersed polyMMA (solid content 10.0%) was obtained.

[Production of monodisperse polymer particles]
First, a monomer mixture obtained by dissolving 6 g of 2,2′-azoisobutyronitrile and 6 g of benzoyl peroxide using 100 g of MMA, 600 g of styrene and 300 g of ethylene glycol dimethacrylate, 15 g of sodium dioctylsulfosuccinate (critical) Mixed with 1000 g of ion-exchanged water containing 12 times the micelle concentration). The mixture was placed in K homomixer Mark 2.5 type (manufactured by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 10 minutes to obtain an emulsion.

  To this emulsion, 45 g of a seed particle dispersion (solid content 10.0%) having an average particle size of 1.00 μm obtained above was added and stirred at 30 ° C. for 4 hours. To this dispersion, 2000 g of a 4% aqueous solution of polyvinyl alcohol GH-17 and 0.6 g of sodium nitrite were added, followed by stirring at 60 ° C. for 3 hours and then at 105 ° C. for 2.5 hours to carry out a polymerization reaction.

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 6.0 μm, the coefficient of variation was 9.1%, and the particle size was 5.2 μm or less in the volume% distribution. 9%, 5.2 to 6.5 μm is 94.4%, 6.5 μm or more is 3.7%, and in the number% distribution, the 25% diameter is 5.7 μm, and the 75% diameter is 6.2 μm. Since the ratio of small particles having a% diameter (4.8 μm) or less was 1.99% in terms of volume and 22.8% in terms of number, it was confirmed that the particles were very well aligned.

Example 3
[Manufacture of seed particles]
The polymerization reaction was carried out under the same conditions as in Example 2.
[Production of monodisperse polymer particles]
The composition of the monomer mixture is 200 g of MMA, 500 g of styrene, 300 g of ethylene glycol dimethacrylate, 6 g of 2,2′-azoisobutyronitrile, 6 g of benzoyl peroxide, and 11.5 g of sodium dioctylsulfosuccinate. The polymerization reaction was carried out under the same conditions as in Example 2 except that the addition amount of the seed particle dispersion was changed to 70 g (9 times the critical micelle concentration).

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 5.4 μm, the coefficient of variation was 7.3%, and the particle size was 4.7 μm or less in the volume% distribution. 1%, 4.7 to 5.8 μm is 95.5%, 5.8 μm or more is 3.4%, and in the number% distribution, the 25% diameter is 5.1 μm, and the 75% diameter is 5.5 μm. Since the ratio of small particles having a% diameter (4.3 μm) or less is 1.16% in terms of volume and 12.7% in terms of number, it is recognized that the particles have very uniform particle diameters. It was.

Example 4
[Manufacture of seed particles]
The polymerization reaction was carried out under the same conditions as in Example 2.
[Production of monodisperse polymer particles]
First, a monomer mixture obtained by dissolving 4.8 g of 2,2′-azoisobutyronitrile and 4.8 g of benzoyl peroxide using 80 g of MMA, 480 g of styrene, and 240 g of ethylene glycol dimethacrylate was converted into dioctylsulfosuccinic acid. Mixed with 800 g of ion-exchanged water containing 24 g of sodium (24 times the critical micelle concentration); The mixture was placed in K homomixer Mark 2.5 type (manufactured by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 10 minutes to obtain an emulsion.

  To this emulsion, 36 g of a seed particle dispersion (solid content: 10.0%) having an average particle diameter of 1.00 μm obtained above was added and stirred at 30 ° C. for 4 hours. To this dispersion were added 2400 g of a 4% aqueous solution of polyvinyl alcohol GH-17 and 0.64 g of sodium nitrite, and then the mixture was stirred at 60 ° C. for 3 hours and then at 105 ° C. for 2.5 hours to carry out a polymerization reaction.

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 6.0 μm, the coefficient of variation was 7.7%, and the particle size was 5.2 μm or less in the volume% distribution. 1%, 5.2 to 6.5 μm is 95.8%, 6.5 μm or more is 3.1%, 25% diameter is 5.7 μm, 75% diameter is 6.1 m in the number% distribution, 80 Since the ratio of small particles having a% diameter (4.8 μm) or less was 1.17% in terms of volume and 20.2% in terms of number, it was confirmed that the particles were very well aligned.

Example 5
[Manufacture of seed particles]
The polymerization reaction was carried out under the same conditions as in Example 2.
[Production of monodisperse polymer particles]
The polymerization reaction was carried out under the same conditions as in Example 2 except that sodium dodecylbenzenesulfonate was changed to sodium dioctylsulfosuccinate to 9.6 g (12 times the critical micelle concentration (0.08 wt%)). .

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 6.0 μm, the coefficient of variation was 7.6%, and the particle size of 5.2 μm or less was 1. 4%, 5.2 to 6.5 μm is 95.2%, 6.5 μm or more is 3.4%, 25% diameter is 5.7 μm, and 75% diameter is 6.1 μm in the number% distribution, 80 Since the ratio of small particles having a% diameter (6.4 μm) or less is 1.55% in terms of volume and 11.0% in terms of number, it is recognized that the particles have very uniform particle diameters. It was.

Example 6
[Manufacture of seed particles]
The polymerization reaction was carried out under the same conditions as in Example 2.
[Production of monodisperse polymer particles]
The composition of the monomer mixture is 500 g of MMA, 200 g of styrene, 300 g of ethylene glycol dimethacrylate, 6 g of 2,2′-azoisobutyronitrile, 6 g of benzoyl peroxide, and 11.5 g of sodium dioctylsulfosuccinate. The polymerization reaction was carried out under the same conditions as in Example 2 except that the addition amount of the seed particle dispersion was changed to 55 g (9 times the critical micelle concentration).

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 5.4 μm, the coefficient of variation was 7.5%, and the particle size was 4.7 μm or less in the volume% distribution. 2%, 4.7 to 5.8 μm is 95.4%, 5.8 μm or more is 3.4%, and in the number% distribution, the 25% diameter is 5.2 μm and the 75% diameter is 5.6 μm. Since the ratio of small particles having a% diameter (4.3 μm) or less is 1.28% in terms of volume and 12.9% in terms of number, it is recognized that the particles have very well-equipped particles. It was.

Example 7
[Manufacture of seed particles]
First, 3000 g of ion-exchanged water and then 500 g of ethyl methacrylate (EMA) in which 10 g of 1-octanethiol was dissolved as a molecular weight regulator were added, and the temperature was raised to 55 ° C. in a nitrogen stream while stirring. After 2.6 g of potassium sulfate was dissolved in 100 g of ion-exchanged water, it was added and stirred at 55 ° C. for 12 hours to conduct a polymerization reaction. A monodispersed polyEMA having an average particle size of 0.5 μm and a weight average molecular weight of 13,000 A dispersion (solid content: 14.3%) was obtained.

[Production of monodisperse polymer particles]
First, using 720 g of styrene and 98 g of divinylbenzene, 6 g of 2,2′-azoisobutyronitrile and 6 g of benzoyl peroxide were dissolved, and 2.4 g of polyoxyethylene octylphenyl ether (critical) Mixed with 1000 g of ion-exchanged water containing 20 times the micelle concentration). The mixture was placed in K homomixer Mark 2.5 type (manufactured by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 10 minutes to obtain an emulsion.

  46 g of the seed particle dispersion (solid content: 14.3%) having an average particle diameter of 0.5 μm obtained above was added to this emulsion and stirred at 30 ° C. for 5 hours. To this dispersion, 2000 g of a 4% aqueous solution of polyvinyl alcohol GH-17 and 0.6 g of sodium nitrite were added, followed by stirring at 60 ° C. for 3 hours and then at 105 ° C. for 2.5 hours to carry out a polymerization reaction.

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 3.5 μm, the coefficient of variation was 8.7%, and the particle size of 3.3 μm or less was 1. 1%, 3.3-4.2 μm is 94.2%, 4.2 μm or more is 4.7%, and the 25% diameter is 3.4 μm and the 75% diameter is 3.6 μm in the number distribution, 80 Since the ratio of small particles having a% particle size (2.8 μm) or less is 1.02% in terms of volume and 9.75% in terms of number, it is recognized that the particles have very uniform particle sizes. It was.

Example 8
[Manufacture of seed particles]
First, 3000 g of ion-exchanged water and then 500 g of MMA in which 10 g of 1-octanethiol was dissolved as a molecular weight regulator were added, and the temperature was raised to 70 ° C. in a nitrogen stream while stirring, and 2.5 g of potassium persulfate as a polymerization initiator. Was dissolved in 100 g of ion-exchanged water, and stirred at 70 ° C. for 12 hours to conduct a polymerization reaction. A dispersion of monodisperse polyMMA having an average particle size of 0.5 μm and a weight average molecular weight of 24,000 (solid content) 14.3%).

[Production of monodisperse fine particles]
First, a monomer mixture obtained by dissolving 6 g of 2,2′-azoisobutyronitrile and 6 g of benzoyl peroxide using 550 g of MMA, 150 g of styrene and 300 g of ethylene glycol dimethacrylate, 11.5 g of sodium dioctylsulfosuccinate (9 times the critical micelle concentration) and mixed with 1000 g of ion-exchanged water. The mixture was placed in K homomixer Mark 2.5 type (manufactured by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 10 minutes to obtain an emulsion.

  To this emulsion, 40 g of a seed particle dispersion (solid content: 14.3%) having an average particle size of 0.5 μm obtained above was added and stirred at 30 ° C. for 3 hours. To this dispersion was added 2000 g of a 4% aqueous solution of polyvinyl alcohol GH-17 and 0.6 g of sodium nitrite, and then the mixture was stirred at 60 ° C. for 3 hours and then at 105 ° C. for 2.5 hours to carry out a polymerization reaction.

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 2.4 μm, the coefficient of variation was 12.8%, and the particle size was 2.0 μm or less in the volume% distribution. 2%, 2.0-3.2 μm is 95.6%, 3.2 μm or more is 2.0%, 25% diameter is 2.24 μm, 75% diameter is 2.44 μm in the number distribution, 80 Since the ratio of small particles having a% diameter (1.9 μm) or less was 2.00% in terms of volume and 9.83% in terms of number, it was confirmed that the particles were very well aligned.

Example 9
[Manufacture of seed particles]
First, 3000 g of ion-exchanged water and then 500 g of MMA in which 10 g of 1-octanethiol was dissolved as a molecular weight regulator were added, and the temperature was raised to 70 ° C. in a nitrogen stream while stirring, and 2.5 g of potassium persulfate as a polymerization initiator. Was dissolved in 100 g of ion-exchanged water, and stirred at 70 ° C. for 12 hours to conduct a polymerization reaction. A dispersion of monodisperse polyMMA having an average particle size of 0.5 μm and a weight average molecular weight of 24,000 (solid content) 14.3%).

  Next, a monomer mixture obtained by dissolving 5 g of 2,2′-azobisisobutyronitrile and 5 g of 1-octanethiol in 200 g of MMA was mixed with 2000 g of ion-exchanged water containing 5 g of sodium dioctylsulfosuccinate. Mixed, T.W. It was put into K homomixer Mark 2.5 type (made by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 5 minutes to obtain an emulsion.

  To this emulsion, 140 g of a seed particle dispersion (solid content: 14.3%) having an average particle size of 0.5 μm obtained above was added and stirred at room temperature for 3 hours. When the dispersion at that time was observed with an optical microscope, it was confirmed that the monomer in the emulsion was completely absorbed by the seed particles. To this dispersion was added 1800 g of a 3.6% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd., GH-17), followed by polymerization at 70 ° C. for 6 hours, an average particle size of 1.00 μm, and a weight average molecular weight of 2. A dispersion of 30,000 monodispersed polyMMA (solid content 10.0%) was obtained.

[Production of monodisperse fine particles]
First, 650 g of MMA, 50 g of styrene, 300 g of ethylene glycol dimethacrylate, 6 g of 2,2′-azoisobutyronitrile and 6 g of benzoyl peroxide were dissolved in a monomer mixture obtained by adding 11.5 g of sodium dioctylsulfosuccinate. (9 times the critical micelle concentration) and mixed with 1000 g of ion-exchanged water. The mixture was placed in K homomixer Mark 2.5 type (manufactured by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 10 minutes to obtain an emulsion.

  To this emulsion, 45 g of a seed particle dispersion (solid content 10.0%) having an average particle size of 1.00 μm obtained above was added and stirred at 30 ° C. for 2 hours. To this dispersion was added 2000 g of a 4% aqueous solution of polyvinyl alcohol GH-17 and 0.6 g of sodium nitrite, and then the mixture was stirred at 60 ° C. for 3 hours and then at 105 ° C. for 2.5 hours to carry out a polymerization reaction.

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 6.2 μm, the coefficient of variation was 7.4%, and the particle size was 5.4 μm or less in the volume% distribution. 4%, 5.4 to 6.7 μm is 94.8%, 6.7 μm or more is 3.8%, and the 25% diameter is 5.9 μm and the 75% diameter is 6.3 μm in the number distribution, 80 Since the ratio of small particles having a% diameter (5.0 μm) or less was 1.21% in terms of volume and 10.9% in terms of number, it was confirmed that the particles were very well aligned.

Example 10
[Manufacture of seed particles]
First, 3000 g of ion-exchanged water and then 100 g of MMA in which 10 g of 1-octanethiol was dissolved as a molecular weight regulator were added. The temperature was raised to 70 ° C. in a nitrogen stream while stirring, and 0.5 g of potassium persulfate as a polymerization initiator. Was dissolved in 50 g of ion-exchanged water and charged, and stirred at 70 ° C. for 12 hours to carry out a polymerization reaction. Next, 400 g of MMA in which 4 g of 1-octanethiol was dissolved and 2 g of potassium persulfate dissolved in 50 g of ion-exchanged water were added, and the mixture was further stirred at 70 ° C. for 3 hours. A dispersion of 40,000 monodispersed polyMMA (solid content 20.0%) was obtained.

[Production of monodisperse polymer particles]
First, a monomer mixture obtained by dissolving 4.8 g of 2,2′-azoisobutyronitrile and 4.8 g of benzoyl peroxide using 700 g of styrene and 100 g of divinylbenzene was dissolved in 8.8 g of sodium dioctylsulfosuccinate. Mixed with 800 g of ion-exchanged water containing 9 times the critical micelle concentration. The mixture was placed in K homomixer Mark 2.5 type (manufactured by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 10 minutes to obtain an emulsion.

  30 g of the seed particle dispersion (solid content: 20.0%) having an average particle diameter of 0.6 μm obtained above was added to this emulsion and stirred at 30 ° C. for 3 hours. To this dispersion, 2000 g of a 4% aqueous solution of polyvinyl alcohol GH-17 and 0.6 g of sodium nitrite were added, followed by stirring at 60 ° C. for 3 hours and then at 105 ° C. for 2.5 hours to carry out a polymerization reaction.

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 3.0 μm, the coefficient of variation was 12.5%, and the particle size was 2.4 μm or less in the volume% distribution. 2%, 2.4-3.6 μm is 92.1%, 3.6 μm or more is 5.7%, and in the number% distribution, the 25% diameter is 2.80 μm, and the 75% diameter is 3.03 μm. Since the ratio of small particles having a% diameter (2.4 μm) or less is 2.18% in terms of volume and 10.6% in terms of number, it is recognized that the particles have very uniform particle diameters. It was.

Example 11
[Manufacture of seed particles]
First, 3000 g of ion-exchanged water, and then 500 g of MMA in which 10 g of 1-octanethiol was dissolved as a molecular weight regulator were added. The temperature was raised to 70 ° C. in a nitrogen stream while stirring, and 2.5 g of potassium persulfate as a polymerization initiator. Was dissolved in 100 g of ion-exchanged water and stirred for 12 hours at 70 ° C. to carry out a polymerization reaction. A dispersion of monodisperse polyMMA having an average particle size of 0.5 μm and a weight average molecular weight of 24,000 (solid content) 14.3%).

  Next, a monomer mixture obtained by dissolving 8 g of 2,2′-azobisisobutyronitrile and 12 g of 1-octanethiol in 800 g of MMA, ion-exchanged water containing 5.5 g of sodium dioctylsulfosuccinate. Mixed with 2200 g; It was put into K homomixer Mark 2.5 type (made by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 5 minutes to obtain an emulsion.

  To this emulsion, 140 g of a seed particle dispersion (solid content: 14.3%) having an average particle diameter of 0.5 μm obtained above was added and stirred at room temperature for 3 hours. When the dispersion at that time was observed with an optical microscope, it was confirmed that the monomer in the emulsion was completely absorbed by the seed particles. To this dispersion, 1200 g of a 3.6% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd., GH-17) was added, followed by polymerization at 70 ° C. for 6 hours, an average particle size of 1.2 μm, and a weight average molecular weight of 1. A 60,000 monodispersed polyMMA dispersion (solid content 20.0%) was obtained.

[Production of monodisperse polymer particles]
First, a monomer mixture obtained by dissolving 6 g of 2,2′-azoisobutyronitrile and 6 g of benzoyl peroxide using 100 g of MMA, 600 g of styrene and 300 g of ethylene glycol dimethacrylate, 11.5 g of sodium dioctylsulfosuccinate (9 times the critical micelle concentration) and mixed with 1000 g of ion-exchanged water. The mixture was placed in K homomixer Mark 2.5 type (manufactured by Tokushu Kika Kogyo Co., Ltd.) and treated at 10,000 rpm for 10 minutes to obtain an emulsion.

  To this emulsion, 57 g of a seed particle dispersion (solid content: 10.0%) having an average particle size of 1.2 μm obtained above was added and stirred at 30 ° C. for 3 hours. To this dispersion, 2000 g of a 4% aqueous solution of polyvinyl alcohol GH-17 and 0.6 g of sodium nitrite were added, followed by stirring at 60 ° C. for 3 hours and then at 105 ° C. for 2.5 hours to carry out a polymerization reaction.

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 5.9 μm, the coefficient of variation was 7.9%, and the particle size was 5.3 μm or less in the volume% distribution. 5%, 5.3 to 6.5 μm is 94.6%, 6.5 μm or more is 3.9%, 25% diameter is 5.7 μm, 75% diameter is 6.1 μm in the number% distribution, 80 Since the ratio of small particles having a% diameter (4.7 μm) or less was 0.95% in terms of volume and 14.6% in terms of number, it was confirmed that the particles were very well aligned.

Comparative Example 1
[Manufacture of seed particles]
The polymerization reaction was carried out under the same conditions as in Example 1.
[Production of monodisperse polymer particles]
The polymerization reaction was carried out under the same conditions as in Example 1 except that the amount of sodium dioctylsulfosuccinate used was 7.5 g (six times the critical micelle concentration).

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 8.1 μm, the coefficient of variation was 10.8%, and the particle size was 7.3 μm or less in the volume% distribution. 4%, 7.3 to 9.1 μm is 96.4%, 9.1 μm or more is 1.2%, and in the number% distribution, the 25% diameter is 1.3 μm, the 75% diameter is 8.0 μm, and 80%. Since the ratio of small particles having a diameter (6.5 μm) or less is 2.39% in terms of volume and 64.6% in terms of number, the number of particles having a small particle size is increased and monodispersed compared to Example 1. Decreased.

Comparative Example 2
[Manufacture of seed particles]
The polymerization reaction was carried out under the same conditions as in Example 2.
[Production of monodisperse polymer particles]
The polymerization reaction was carried out under the same conditions as in Example 2 except that the amount of sodium dioctylsulfosuccinate used was 10 g (8 times the critical micelle concentration).

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 5.8 μm, the coefficient of variation was 13.8%, and the particle size was 5.2 μm or less in the volume% distribution. 7%, 5.8-6.5 μm is 89.6%, 6.5 μm or more is 3.7%, 25% diameter is 2.5 μm, 75% diameter is 6.0 μm in the number% distribution, and 80%. The proportion of small particles having a diameter (4.6 μm) or less is 6.66% in terms of volume and 44.6% in terms of number. Decreased.

Comparative Example 3
[Manufacture of seed particles]
The polymerization reaction was carried out under the same conditions as in Example 2.
[Production of monodisperse polymer particles]
The polymerization reaction was carried out under the same conditions as in Example 3 except that the amount of sodium dioctylsulfosuccinate used was 10 g (8 times the critical micelle concentration).

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 5.2 μm, the coefficient of variation was 10.9%, and the particle size was 4.7 μm or less in the volume% distribution. 1%, 4.7-5.8 μm is 92.4%, 5.8 μm or more is 5.5%, 25% diameter is 3.6 μm, 75% diameter is 5.4 μm and 80% in the number% distribution. Since the proportion of small particles having a diameter (4.2 μm) or less is 3.11% in terms of volume and 26.8% in terms of number, the number of particles having a small particle size is increased as compared with Example 3 and monodispersed. Decreased.

Comparative Example 4
[Manufacture of seed particles]
The polymerization reaction was carried out under the same conditions as in Example 2.
[Production of monodisperse polymer particles]
The polymerization reaction was carried out under the same conditions as in Example 4 except that the amount of sodium dioctylsulfosuccinate used was 32 g (32 times the critical micelle concentration), but the particles were aggregated to obtain monodisperse polymer particles. I couldn't.

Comparative Example 5
[Production of seed particles by the dispersion polymerization method]
Polyvinylpyrrolidone (weight average molecular weight 40,000) 20 g, styrene 300 g, and t-butyl peroxyoctoate 15 g were dissolved in isopropyl alcohol 1000 g. The temperature was raised to 70 ° C. in a nitrogen stream while stirring, and the mixture was heated at 70 ° C. for 24 hours. Polymerization reaction was performed to obtain polymer particles having an average particle diameter of 3.5 μm and a weight average molecular weight of 46,000.

[Production of monodisperse polymer particles]
A monomer mixture prepared by dissolving 0.5 g of 2,2′-azobis- (2,4-dimethylvaleronitrile) in 176 g of styrene and 24 g of divinylbenzene (80% pure) was added to 1.6 g of sodium dodecylbenzenesulfonate ( 5 times the critical micelle concentration) and 400 g of dissolved ion-exchanged water. It processed for 10 minutes at 8000 rpm using K homomixer Mark2.5 type (made by Tokushu Kika Kogyo). When the obtained emulsion is added to 200 g of an aqueous dispersion (10% solid content) of polystyrene seed particles obtained by the dispersion polymerization method and stirred at room temperature for 2 hours, the monomers in the emulsion are completely seed particles. Was absorbed. After adding 400 g of 5% aqueous solution of polyvinyl alcohol GH-23 (manufactured by Nippon Synthetic Chemical Industry) to this dispersion, polymerization was carried out at 70 ° C. for 8 hours. When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 6.5 μm, the particle size of 7.5 μm or more was 6.6%, and 6.0 to 7.5 μm. 92.3%, 6.0 μm or less was 1.1%, and many coarse particles were generated.

Comparative Example 6
[Manufacture of seed particles]
The polymerization reaction was carried out under the same conditions as in Example 8.
[Production of monodisperse fine particles]
The polymerization reaction was carried out under the same conditions as in Example 8, except that the amount of sodium dioctylsulfosuccinate used was 5 g (4 times the critical micelle concentration).

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 2.6 μm, the coefficient of variation was 33.4%, and the particle size was 2.0 μm or less in the volume% distribution. 4%, 2.0-3.2 μm is 90.3%, 3.2 μm or more is 7.3%, 25% diameter is 2.23 μm, 75% diameter is 2.45 μm in the number% distribution, and 80% Since the proportion of small particles having a diameter (2.1 μm) or less is 4.08% in terms of volume and 19.3% in terms of number, the coefficient of variation is significantly increased compared to Example 8 and monodispersity is achieved. Decreased.

Comparative Example 7
[Manufacture of seed particles]
The polymerization reaction was carried out under the same conditions as in Example 9.
[Production of monodisperse fine particles]
The polymerization reaction was carried out under the same conditions as in Example 9, except that the amount of sodium dioctylsulfosuccinate used was 5 g (4 times the critical micelle concentration).

  When the particle size distribution of the obtained polymer particles was measured with a Coulter counter manufactured by Coulter, the average particle size was 5.9 μm, the coefficient of variation was 10.6%, and the particle size of 5.4 μm or less was 5 in the volume% distribution. 0.0%, 5.4 to 6.7 μm is 92.7%, 6.7 μm or more is 2.3%, and in the number% distribution, the 25% diameter is 3.5 μm, the 75% diameter is 6.3 μm, and 80 The ratio of small particles having a% diameter (4.7 μm) or less is 4.3% in terms of volume and 29.9% in terms of number. Dispersibility decreased.

FIG. 1 shows the particle size distribution represented by the number% of the polymer particles obtained in Example 1 and Comparative Example 1 above. Furthermore, those electron micrographs are shown in FIG.
From these results, it can be seen that the polymer particles obtained in Example 1 are superior in monodispersibility as compared with the polymer particles obtained in Comparative Example 1.
Moreover, it shows in Table 1 collectively about each composition used for manufacture of the polymer particle in said Examples 1-11 and Comparative Examples 1-7, and the obtained polymer particle.

In Examples 1 to 11, the amount of the surfactant used was set to 9 to 24 times the critical micelle concentration, and as a result, polymer particles excellent in monodispersibility were obtained.
However, in Comparative Examples 1 to 3 and Comparative Examples 5 to 7, the amount of surfactant used was set to less than 9 times the critical micelle concentration, resulting in the generation of many small particles and excellent monodispersity. Polymer particles could not be obtained.
In Comparative Example 4, the amount of the surfactant used was set to a value exceeding 24 times the critical micelle concentration. As a result, the polymer particles aggregated and primary particles could not be obtained.
Therefore, the method of the present invention is an excellent method for obtaining polymer particles having a uniform particle diameter (highly monodispersed) with high productivity in seed polymerization of a hydrophobic monomer.

Claims (7)

A method for producing monodisperse polymer particles by a seed polymerization method in which a monomer is absorbed in seed particles in an aqueous medium and then the monomer is polymerized,
The monomer contains 5% by weight or more of a hydrophobic vinyl monomer and is absorbed by the seed particles by 80 parts by weight or more with respect to 1 part by weight of the seed particles;
The method for producing monodisperse polymer particles, wherein the aqueous medium contains a surfactant in an amount of 9 to 24 times the critical micelle concentration. The monodisperse polymer particles include small particles of 2.2% or less in terms of volume, or 25% or less in terms of number,
The method for producing monodisperse polymer particles according to claim 1, wherein the small particles are particles having a particle diameter of 80% or less of an average particle diameter of the monodisperse polymer particles.   The method for producing monodisperse polymer particles according to claim 1 or 2, wherein the monodisperse polymer particles have a particle diameter of 4.5 or more when the particle diameter of the seed particles is 1.   The method for producing monodisperse polymer particles according to any one of claims 1 to 3, wherein the surfactant is an anionic surfactant.   The hydrophobic vinyl monomer is a monomer having a solubility in water at 25 ° C. of 1 g / L or less, and the monomer is a monomer other than the hydrophobic vinyl monomer. The manufacturing method of the monodisperse polymer particle as described in any one of Claims 1-4 containing 95 weight% or less.   The method for producing monodisperse polymer particles according to any one of claims 1 to 5, wherein the monomer is absorbed by the seed particles in an amount of 100 to 300 parts by weight with respect to 1 part by weight of the seed particles.   The method for producing monodisperse polymer particles according to any one of claims 1 to 6, wherein the hydrophobic vinyl monomer is selected from monofunctional or polyfunctional styrenes.