JPH0597906A - Method for producing polymer fine particles - Google Patents

Abstract

(57) [Summary] [Objective] To develop a method for stably and efficiently producing polymer fine particles having a narrow particle size distribution on the order of microns. [Structure] A monomer composed of a vinyl aromatic compound or a (meth) acrylic acid ester is dissolved in a solvent in which the (meth) acrylic acid ester is dissolved in a solvent which dissolves the monomer and does not dissolve the (co) polymer produced. A (co) polymer (component A) composed of monomer units and a monomer of a type different from the above-mentioned component A, composed of monomer units of vinyl aromatic compound and (meth) acrylic acid ester. This is a method of producing polymer fine particles by (co) polymerization using an AB type block copolymer composed of a (co) polymer (B component) containing units as a dispersion stabilizer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polymer fine particles, and more specifically, by using a specific dispersion stabilizer, polymer fine particles of micron order and narrow particle size distribution can be produced stably and efficiently. Regarding the method.

[0002]

2. Description of the Related Art Micron is used in various fields such as toners used for electrophotography, electrostatic photography, electrostatic recording, carriers for column chromatograms, cosmetic powder for blocking ultraviolet rays, and medical clinical diagnosis. Orders, especially 0.
Fine particles having a particle size distribution of 5 to 30 microns and a narrow particle size distribution are strongly desired.

[0003] Conventionally, it has been studied to produce resin particles for these uses by an emulsion polymerization method, a seed emulsion polymerization method, and a suspension polymerization method. However, depending on the emulsion polymerization method, there is a problem that only resin particles of 1 micron or less can be obtained. Further, in the seed emulsion polymerization method, particles having a narrow particle size distribution on the order of microns are obtained (for example, JP-A-58-106554).
This is because the preparation of polymer fine particles having a particle size of about 0.5 micron is required, and then the particle size needs to be increased by the polymerization of the next several steps in order to increase the particle size, and the operation is extremely complicated. is there. Furthermore, the suspension polymerization method can only give particles having a large particle size, and the particle size distribution is wide.

On the other hand, J. Polym. Sci. Polym.
There is known a method of dispersion polymerization in an organic solvent system as shown in Chem. Ed. Vol. 24, p. 2995 to 3007 (1986). In this method, the fine particles of the polymer are obtained by dissolving the monomer in an organic solvent in which the monomer is dissolved but not the produced polymer, and polymerization is performed. In addition, JP-A-6
3-191805 and 63-191806, in producing monodisperse particles by this dispersion polymerization method, as a dispersion polymerization stabilizer, partially saponified polyvinyl alcohol or partially saponified polyvinyl alcohol having a mercapto group at the molecular end. Is proposed to be used.

[0005]

Dispersion polymerization using the above organic solvent gives fine polymer particles having a uniform particle size on the order of microns, but in order to control the particle size, narrow polymerization conditions must be set. It has the drawback of not becoming. For example, it is very difficult to obtain monodisperse resin particles with a desired particle size, because the particle size distribution greatly varies with the particle size due to changes in the polymerization temperature and the amount of the polymerization initiator. Further, when producing a resin having a relatively large particle size, if polymerization is advanced to a high polymerization rate, there is a problem in polymerization stability such as blocking or generation of particles having a small particle size.

By the way, conventionally, as the dispersion stabilizer in the above-mentioned dispersion polymerization, those which are uniformly dissolved in an organic solvent in which a monomer is dissolved but a produced polymer is not dissolved have been used. It is considered that this dispersion stabilizer is adsorbed on the surface of particles generated during dispersion polymerization and acts as a protective colloid, and the dispersion stabilizer and the polymer form a graft or block copolymer during the polymerization. It is speculated that this copolymer functions as a protective colloid agent. However, this graft or block copolymer is produced during polymerization, and its production rate and production amount are substantially difficult to control. Especially when obtaining monodisperse resin particles in the micron order, the amount of dispersion stabilizer is kept as small as possible to keep the polymerization site inside the particles and suppress the polymerization in the solution to generate new particles as much as possible. You must stop. In such a case, there are many cases where a problem occurs in the polymerization stability or the monodispersity is destroyed at the final stage of the polymerization. In addition, the particle size and distribution of the resin particles to be obtained largely change due to slight changes in the polymerization conditions, particularly the polymerization temperature and the amount of catalyst added, and this adjustment is extremely difficult.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for stably and efficiently producing monodisperse polymer fine particles having a particle size on the order of microns and an extremely narrow particle size distribution. It is in. The inventors of the present invention have made extensive studies to develop a method for producing resin particles which is easy to control the particle size and particle size distribution and has excellent polymerization stability. As a result, as the dispersion stabilizer, a homopolymer or copolymer (component A) composed of acrylic acid ester and / or methacrylic acid ester monomer units and a vinyl aromatic compound, acrylic acid ester and / or An AB block copolymer composed of a methacrylic acid ester monomer unit and a homopolymer or copolymer (component B) containing a monomer unit of a different type from the component A. It was found that the above object can be achieved by using The present invention has been completed based on these findings.

That is, the present invention dissolves and produces one or more monomers selected from the group consisting of vinyl aromatic compounds, acrylic esters and methacrylic esters. Consisted of one or more monomer units selected from the group consisting of acrylic acid esters and methacrylic acid esters in an organic solvent that does not dissolve the polymer or copolymer or a mixed solvent of the organic solvent and water. A homopolymer or copolymer (component A), a vinyl aromatic compound, one or more monomer units selected from the group consisting of acrylic acid esters and methacrylic acid esters, and Use as a dispersion stabilizer an AB block copolymer composed of a homopolymer or copolymer (component B) containing a different type of monomer unit from the component A Te, there is provided a method for producing polymer microparticles, characterized in carrying out the polymerization or copolymerization.

In the method of the present invention, the monomers to be polymerized or copolymerized (raw material monomers) are vinyl aromatic compounds, acrylic acid esters and methacrylic acid esters, which may be used alone. Well, two or more kinds may be used in combination. Here, as the vinyl aromatic compound,
Examples thereof include various ones, for example, alkyl vinyl benzene (alkyl styrene) such as styrene, α-methyl styrene, α-ethyl styrene, p-methyl styrene, o.
Preferable examples include alkyl nucleus-substituted styrenes such as -methylstyrene and p-ethylstyrene, and further divinylbenzene. Moreover, as acrylic acid ester or methacrylic acid ester (hereinafter, acrylic acid or methacrylic acid is collectively abbreviated as (meth) acrylic acid), methyl (meth) acrylate, ethyl (meth) acrylate, (meth ) Propyl acrylate,
Butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate,
Suitable examples include stearyl (meth) acrylate and the like.

The solvent used in the method of the present invention is an organic solvent which dissolves the above-mentioned monomer but does not dissolve the produced polymer or copolymer, or a mixed solvent of this organic solvent and water. .. Here, as the organic solvent,
As described above, various substances can be used without particular limitation as long as they dissolve the monomer as the raw material but do not dissolve the polymer or copolymer to be produced. Of these, monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol and butyl alcohol, ether alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monobutyl ether, ethers such as tetrahydrofuran and dimethoxyethane are preferred. Examples thereof include organic acid esters such as methyl acetate and ethyl acetate. You may use these organic solvents individually or in mixture of 2 or more types. The solvent used in the method of the present invention is the above organic solvent or a mixed solvent of this organic solvent and water. The proportion of water in this mixed solvent varies depending on the properties of the monomer used and the polymer to be produced, and the type of the organic solvent to be mixed, and cannot be unambiguously determined, but usually, it is based on the total amount of the mixed solvent. 40% by weight or less. Further, in the method of the present invention, the mixing ratio of the solvent and the monomer as the raw material may be appropriately selected according to various situations, but usually solvent / monomer = 60/40 to 95.
/ 5 (weight ratio), preferably 70/30 to 90/10
(Weight ratio).

The dispersion stabilizer used in the method of the present invention is
As described above, from a homopolymer or copolymer (component A) composed of one or more monomer units composed of (meth) acrylic acid ester, a vinyl aromatic compound and (meth) acrylic acid ester. An AB block copolymer composed of one or more kinds of monomer units, and a homopolymer or copolymer (B component) containing a monomer unit of a different type from the above-mentioned A component. It is a polymer. The component A in the AB block copolymer is a component which is dissolved and compatible with an organic solvent or a mixed solvent of organic solvent / water, and which functions as a protective colloid for the resin particles produced, ) Acrylic ester polymer.

Here, the (meth) acrylic acid ester-based polymer includes methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and hexyl (meth) acrylate. , A homopolymer obtained by polymerizing or copolymerizing one or more of octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, or the like. It is a copolymer. In addition, this (meth) acrylic acid ester-based polymer may have a functional group such as a carboxyl group, a sulfonic acid group, an ammonium salt group or a silyl group in the molecule, if necessary, in order to improve the compatibility with the solvent used. It may contain a group. The molecular weight of the component (A) composed of the (meth) acrylic acid ester-based polymer is not particularly limited, and its preferred range varies depending on various situations, but it is usually 5,000 to 200,000, preferably 7,000 to 7,000 as a number average molecular weight. 10
It is 0000. If the number average molecular weight is less than 5,000, the role of the produced polymer as a protective colloid is not sufficiently exhibited. On the contrary, if the number average molecular weight is more than 200,000, problems may occur during production of the AB block copolymer. is there.

On the other hand, the component B of the dispersion stabilizer has a property of being dissolved or compatible with the monomer as a raw material (preferably a property of being dissolved), although it is not dissolved in the above-mentioned solvent to form micelles. It has the property of becoming the core of time. The component B of the dispersion stabilizer preferably has the property of being dissolved or compatible with the polymer produced. The component B is composed of one or more monomer units selected from the group consisting of vinyl aromatic compounds and (meth) acrylic acid esters, and is of a type different from the above component A. Homopolymers or copolymers containing monomer units are used. Here, specific examples of the vinyl aromatic compound and the (meth) acrylic acid ester include the same as the above-mentioned raw material monomer. However,
The raw material monomer used and the monomer constituting the B component may not necessarily be the same kind. Further, the component A and the component B of the dispersion stabilizer each express the above-mentioned function, and both can contain a (meth) acrylic acid ester as a constituent monomer thereof. Needs to contain a monomer unit of a different type from the monomer unit constituting the component A. The number average molecular weight of component B is not particularly limited, but is generally 300 to 50,000, preferably 70.
It is 0 to 20000. When the number average molecular weight is less than 300, when added to the reaction system, the cohesive force may be insufficient and micelle formation may be incomplete. Again 50,000
If it exceeds, the micelle nucleus may become too large to form stable micelles, and there is a problem that the number of micelles cannot be controlled sufficiently.

As described above, the dispersion stabilizer used in the method of the present invention is an AB type block copolymer consisting of both components A and B, but the dispersion stabilizer does not impair the intended function. In addition, it is also possible to add other components as needed. Further, the A and B components in this AB type block copolymer can take arbitrary values within the ranges of the number average molecular weights described above. As described above, the dispersion stabilizer of the present invention is characterized in that it has both the A component that functions as a protective colloid of the polymer to be produced and the B component that functions as the nucleus of the micelle to be formed, and that it exerts two functions at the same time. Have. When this dispersion stabilizer is dissolved by adding it to an organic solvent or a mixed solvent of this organic solvent and water, in which the monomer dissolves but the resulting polymer does not dissolve, it does not dissolve homogeneously and transparent, and a bluish white emulsion. Present. This indicates that micelles having the component B as the nucleus and the component A as the protective colloid were generated even when the monomer was not added. Therefore, by adjusting the addition amount of this dispersion stabilizer, the number of micelles can be easily controlled, and the particle size can also be freely controlled. Moreover, since polymerization outside the micelles hardly occurs, it provides excellent monodispersity. Further, the decrease in dispersion stability due to the progress of polymerization can be easily suppressed by adjusting the molecular weight of each component of the AB block copolymer. Further, even if the polymerization temperature or the amount of the catalyst used changes to some extent, the generation rate or the amount of the graft or block copolymer does not change unlike the conventional stabilizer, and therefore the particle size and the monodispersity are improved. It does not change significantly. The method of the present invention is similar to seed emulsion polymerization in the mechanism that seed particles are generated before polymerization, the field of polymerization is only in micelles, and the particles increase as the polymerization proceeds. However, it is remarkably different in that micron-order monodisperse resin particles can be obtained by a single reaction. The method of using the AB block copolymer as a dispersion stabilizer as in the method of the present invention is essentially different from the dispersion stabilizers which are conventionally known to be dissolved in an organic solvent. , Is a completely new method. In the method of the present invention, the amount (blending ratio) of the dispersion stabilizer made of the AB block copolymer is not particularly limited and may be appropriately determined according to various situations, but it is usually 0.5 to 25 parts by weight based on 100 parts by weight of the raw material monomer,
It is preferably selected in the range of 2 to 15 parts by weight.

The dispersion stabilizer of the present invention can be manufactured by various methods. Among them, suitable manufacturing methods are as follows (1) to (5). (1) First, thioacetic acid is used as a chain transfer agent to polymerize the monomer constituting the component A or the component B in the presence of a polymerization initiator to obtain a polymer having a thioacetic acid group at the molecular end. Next, the thioacetic acid group is hydrolyzed in the presence of an acid or alkali catalyst to synthesize a polymer having a thiol group at the molecular end, and the other component is added in the presence of the polymer containing the thiol group. According to the method of polymerizing the above, the desired AB type block copolymer is obtained. (2) A desired AB type block copolymer is produced by the method described in Kogaku Kobunshi Vol. 44, p. 73-79 (1987).
That is, by using a polymer having a plurality of peroxide bonds in the molecule as an initiator to polymerize component A or component B, and then polymerize the other component, an AB type block copolymer is prepared. Is obtained. (3) A method by living anionic polymerization using a catalyst such as butyllithium. (4) First, a monomer constituting one component is subjected to living anion polymerization, then carbon dioxide gas is charged into the system to prepare a polymer having a carboxyl group introduced at the molecular end of the polymer. Next, a polymer having an amino group at the terminal of a molecule prepared by polymerizing a monomer of another component using a radical initiator having an amino group is separately prepared, and both polymers are condensed and coupled by a method of coupling. The desired AB block copolymer is produced. (5) By introducing a functional group into the polymer end of each of the A and B components, and subsequently coupling these polymers with a polyvalent isocyanate compound or a polyvalent epoxy compound, the desired AB type A block copolymer is obtained.

In the method of the present invention, the monomers are polymerized or copolymerized in the presence of the above-mentioned dispersion stabilizer. In this case, it is preferable to use a polymerization initiator. However, it is also possible to initiate the polymerization by irradiation with active energy rays such as radiation without using a polymerization initiator. When a polymerization initiator is used, various types of polymerization initiator can be used as long as they are soluble in the solvent used. For example, general radical initiators such as benzoyl peroxide, azobisisobutyronitrile and lauroyl peroxide can be used. The compounding ratio of the polymerization initiator is not particularly limited, but is generally 0.1 to 1 with respect to 100 parts by weight of the raw material monomer.
It is 0 part by weight, preferably 0.5 to 5 parts by weight. When a polymerization initiator having a short half-life is used, it may be added all at once at the initial stage of polymerization, or may be added afterward (delay addition) at appropriate intervals. In carrying out the method of the present invention, the reaction temperature is appropriately set depending on the particle size of the intended resin particles, but it should generally be set in the range of 40 to 90 ° C, preferably 50 to 75 ° C. is there.

An example of the manufacturing process in the method of the present invention will be briefly described as follows. That is, a solvent is charged into a polymerization tank equipped with a stirrer, a reflux condenser, and a nitrogen introducing device, and then the above-mentioned dispersion stabilizer is added, and the nitrogen is sufficiently replaced with stirring, followed by heating and dissolving at a predetermined temperature.
At this time, the system shows a pale milky white color, confirming that the dispersion stabilizer forms micelles. Then, a predetermined amount of monomer and a polymerization initiator are added to start the polymerization reaction. The produced polymer proceeds in the micelle, and the particle size increases with the polymerization rate. After the polymerization is carried out for a predetermined time, it is cooled to stop the polymerization reaction. The obtained resin fine particles are washed and dried after draining. Regarding the operation after the polymerization, various methods such as repeated washing and freeze-drying can be used.

According to the method of the present invention, the average particle size is 0.5 to 3
Polymer fine particles having a diameter of 0 μm, preferably 1 to 10 μm, and a variation coefficient (standard deviation / average particle size × 100) of 30% or less are easily obtained. Also, in carrying out this method,
An organic or inorganic pigment such as carbon black or silica, a wax, a monomer having a dye structure, a polyvalent vinyl compound, an antistatic agent or the like may be appropriately added to the system for polymerization.

[0019]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto. In the examples, "%" and "parts" are based on weight unless otherwise specified. Example 1 Styrene was polymerized in a toluene solvent using thioacetic acid as a chain transfer agent to obtain polystyrene having a thioacetic acid group at the molecular end. The polystyrene was hydrolyzed with a thioacetic acid group using a sodium hydroxide catalyst to produce polystyrene having a thiol group at the molecular end. The gel permeation chromatograph (G
When the (PC) measurement was carried out, the polystyrene reduced number average molecular weight was 6,300 and the weight average molecular weight was 13,200. Next, in the presence of polystyrene having a thiol group at its molecular end, block copolymerization of butyl acrylate is carried out in a toluene solvent at 60 ° C. to obtain A of polystyrene (component B) and polybutyl acrylate (component A). A B-type block copolymer was obtained. When the molecular weight of the obtained block copolymer was measured by GPC analysis, the number average molecular weight of the polystyrene portion was 6300 and the number average molecular weight of the polybutyl acrylate portion was 36000. In a 500 ml glass separable flask equipped with an inclined paddle stirrer, a thermometer, a nitrogen inlet, a monomer inlet and a reflux condenser, 180 ml of ethyl alcohol and 120 ml of methyl acetate were placed as a solvent, After 3.6 g of an AB type block copolymer was charged and the atmosphere was sufficiently replaced with nitrogen, the internal temperature was raised to 70 ° C. At this time, the inside of the flask was pale milky white, and it was confirmed that micelles were generated. A mixture of 45 g of styrene and 0.45 g of azobisisobutyronitrile as a polymerization initiator was added, and the polymerization was continued at 70 ° C. for 12 hours. Polymerization rate is 98.2
%, The dispersibility of the slurry was stable both during and after the polymerization, and no polymer adhesion to the stirrer or the vessel wall was observed. The average particle size, standard deviation and coefficient of variation of the polymer fine particles obtained using a Coulter counter (manufactured by Coulter Electronics Co .; Model Coulter Multisize II) were measured to find 5.9 μm and 0.68 μm, respectively. It was 11.5%.

Example 2 Using thioacetic acid as a chain transfer agent, polymerization of methyl methacrylate was carried out in a toluene solvent at 60 ° C. to obtain polymethyl methacrylate having a thioacetic acid group at the molecular end. The thioacetic acid group was hydrolyzed from this methyl polymethacrylate using a sodium hydroxide catalyst to produce methyl polymethacrylate (component A) having a thiol group at the molecular end. Next, styrene was polymerized in the presence of this methyl polymethacrylate (component B) to produce an AB type block copolymer. The number-average molecular weight of the component A of the obtained AB type block copolymer was 34000, and B
The number average molecular weight of the component was 9,000. Using the same polymerization apparatus as in Example 1, the above AB block copolymer 3. was added to 300 ml of a mixed solvent of methyl alcohol and methyl acetate (methyl alcohol: methyl acetate = 1: 1). Charge 0 g, replace with nitrogen and adjust the internal temperature to 65 ° C.
The temperature was raised to. Also at this time, it was confirmed that milky white emulsion-like micelles were formed. Next, in the polymerization device,
45 g of styrene and benzoyl peroxide as a polymerization initiator.
5 g was charged and the polymerization was continued at 65 ° C. for 20 hours. To see the particle size and particle size distribution of the obtained polymer particles,
When measured with a Coulter counter, the average particle size due to weight distribution was 4.4 μm, the standard deviation was 1.02 μm, and the coefficient of variation was 23.2%.

Example 3 In addition to using 4.5 g of the block copolymer used in Example 2, a mixture of styrene 31.5 g and butyl methacrylate 13.5 g was used as a monomer, and the polymerization temperature was 65 ° C. The polymerization reaction was carried out in the same manner as in Example 1 except that the polymerization time was 40 hours. The polymer particles thus obtained were measured with a Coulter counter to see the particle size and particle size distribution. The average particle size by weight distribution was 8.4 μm, the standard deviation was 1.08 μm, and the coefficient of variation was 12.9.
%Met. When the molecular weight of this polymer was measured by GPC, the weight average molecular weight of the polymer was 44600 and the number average molecular weight was 18500.

Example 4 Anionic living polymerization of styrene was carried out in a toluene solvent using butyllithium as a polymerization catalyst. After polymerization,
Carbon dioxide was introduced into the polymerization system while cooling to obtain polystyrene (component B) having a carboxyl group at the molecular end.
On the other hand, 2,2'-azobis (2-amidinopropane) 2
Butyl methacrylate was polymerized in ethyl acetate using the hydrochloride as a polymerization catalyst to produce polybutyl methacrylate (component A) having an amino group at the molecular end. From the GPC analysis of the obtained polymers of both components A and B, the number average molecular weight of polystyrene was 3200 and the number average molecular weight of butyl polymethacrylate was 125,000. The two polymers were mixed in γ-butyrolactone at 180 ° C. for 2
After dehydration condensation for 0 hour, an AB type block copolymer was produced. Instead of the block copolymer used in Example 2,
Dispersion polymerization was carried out in the same manner as in Example 2, except that 30 g of methyl methacrylate and 15 g of styrene were used, except that the above block copolymer was used. The particle size and particle size distribution of the obtained polymer particles were measured with a Coulter counter, and the average particle size by weight distribution was 2.1 μm.
m, the standard deviation was 0.48 μm, and the coefficient of variation was 22.9%.

Example 5 Polymerization was carried out by changing the amount of azobisisobutyronitrile as a polymerization initiator in the polymerization reaction carried out in Example 1. With respect to the obtained polymer slurry, the average particle diameter and the standard deviation due to the weight distribution of the polymer particles were measured with a Coulter counter. The results are shown in Table 1.

[0024]

[Table 1]

It can be seen from Table 1 that the polymerization rate of styrene changes greatly depending on the amount of the catalyst added, but the particle size and particle size distribution do not change significantly and take a substantially constant value.

Comparative Example 1 The dispersion polymerization of styrene was carried out in the same manner as in Example 1 except that polybutyl acrylate having a number average molecular weight of 32000 was used instead of the dispersion stabilizer used in Example 1. When a polymerization time of 6 hours (polymerization rate of 39%), aggregation of the polymer started and polystyrene adhered to the stirrer and the vessel wall, and the polymerization could not be continued. In addition, when the obtained polymer was observed with an electron microscope, spherical particles were not formed.

Comparative Example 2 The same as in Example 1, except that the precursor of the block copolymer prepared in Example 2 and methyl polymethacrylate having a thiol group at the end (number average molecular weight 13300) were used as dispersion stabilizers. Dispersion polymerization of styrene was carried out in the same manner as in Example 2 except that the concentration of the polymerization initiator and the polymerization temperature were changed under the experimental conditions of. The particle size and particle size distribution of the obtained polymer particles were measured with a Coulter counter. The average particle size by weight distribution was 5.3 μm, and the standard deviation was
The coefficient of variation was 3.49 μm and the coefficient of variation was 65.8%.

Example 6 By the same method as in Example 2, lauryl acrylate was polymerized (component B) in the presence of methyl polymethacrylate having a thiol group at the molecular end (component A), and A-
A B-type block copolymer was produced. The number average molecular weight of the component A of the obtained AB block copolymer was 35,000, and the number average molecular weight of the component B was 10,000. Using a polymerization apparatus similar to that in Example 1, a mixed solvent of methyl alcohol and methyl acetate (methyl alcohol:
Methyl acetate = 2: 3) 300 ml and A above
-B-type block copolymer (3.0 g) was charged, and after nitrogen substitution,
The internal temperature was raised to 65 ° C. Also at this time, it was confirmed that milky white emulsion-like micelles were formed. Next, 45 g of lauryl methacrylate and 0.5 g of benzoyl peroxide as a polymerization initiator were charged into the above polymerization apparatus, and the mixture was heated at 65 ° C. for 2 hours.
Polymerization was continued for 0 hours. The particle size and particle size distribution of the obtained polymer particles were measured with a Coulter counter, and the average particle size by weight distribution was 3.8μ.
m, the standard deviation was 0.80 μm, and the coefficient of variation was 21.1%.

[0029]

EFFECTS OF THE INVENTION According to the method of the present invention, the resin particles obtained have excellent monodispersity, and moreover, the particle size of the resin particles can be freely adjusted only by adjusting the addition amount of the dispersion stabilizer used. Can be controlled. In addition, even if the polymerization conditions change to some extent, the particle size and particle size distribution of the resin particles obtained do not change significantly, and a stable dispersed state can be maintained until the end of the polymerization. The resin particles obtained by the method of the present invention are polymer fine particles having excellent monodispersity on the order of micron, and are used in electrophotography, electrostatic photography, electrostatic recording and the like, and column chromatograms. It is widely and effectively used in various fields such as a carrier for cosmetics, a cosmetic powder for blocking ultraviolet rays, and a medical clinical diagnosis.

Claims (1)

[Claims] 1. A polymer or copolymer which dissolves and produces one or more monomers selected from the group consisting of vinyl aromatic compounds, acrylic acid esters and methacrylic acid esters. A single polymer composed of one or more monomer units selected from the group consisting of acrylic acid esters and methacrylic acid esters in an organic solvent that does not dissolve the polymer or a mixed solvent of the organic solvent and water. A component or a copolymer (A component) and one or more monomer units selected from the group consisting of vinyl aromatic compounds, acrylic acid esters and methacrylic acid esters, and the A component is Polymerization or copolymerization is performed by using an AB type block copolymer composed of a homopolymer or a copolymer (component B) containing different types of monomer units as a dispersion stabilizer. A method for producing polymer fine particles, which comprises carrying out a combination.