JP2000264906A - Production of polymer fine particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing polymer fine particles having a controlled particle diameter distribution and a standard deviation by a ready operation. SOLUTION: In this method for obtaining polymer fine particles by mixing seed polymer particles dispersed into an aqueous dispersion medium with a water dispersion of an oil-soluble ethylenic unsaturated monomer, absorbing the oil-soluble ethylenic unsaturated monomer in the seed polymer particles and polymerizing the monomer in the presence of an oil-soluble polymerization initiator, the mixing of the seed polymer particles dispersed in the aqueous dispersion medium and the water dispersion of the oil-soluble ethylenic unsaturated monomer is carried out by adding the seed polymer particles dispersed in the aqueous dispersion to the water dispersion stepwise or continuously.

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 having a controlled particle size distribution and standard deviation using a seed polymerization method.

[0002]

2. Description of the Related Art
As a method of obtaining particles with a controlled standard deviation or particle size distribution, a method of classifying particles having a large standard deviation obtained by suspension polymerization by a dry or wet method, and re-mixing a plurality of particles to obtain a particle size distribution. There is a method of controlling, a method of mixing several kinds of particles having a narrow particle size distribution obtained by seed polymerization, and the like.

However, when the suspension polymerization method is used, the classification operation is complicated, the yield is low, and the remixing is extremely inefficient. On the other hand, in the seed polymerization method, only those having a very small standard deviation after polymerization can be synthesized, and the particle size distribution is based on the seed polymer particles used, the amount of monomer absorbed by the seed polymer particles, and the amount of monomer absorbed. It was almost uniquely defined by factors such as the composition and the average particle size after polymerization, and had a bimodal distribution, so that it could be controlled only in a very limited range. Therefore, when the seed polymerization method is used, it is necessary to synthesize several kinds of particles having different average particle diameters in advance and then mix them, which also has a disadvantage that the efficiency is extremely low.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a seed polymer particle (hereinafter referred to as a seed polymer particle slurry) dispersed in an aqueous dispersion medium and an aqueous oil-soluble ethylenically unsaturated monomer dispersion (hereinafter referred to as a monodisperse). Water dispersion), and the oil-soluble ethylenically unsaturated monomer is absorbed by the seed polymer particles and polymerized in the presence of an oil-soluble polymerization initiator to obtain polymer fine particles. The present invention provides a method for producing polymer fine particles, wherein mixing of a polymer aqueous dispersion and a monomer aqueous dispersion is carried out by adding a seed polymer particle slurry stepwise or continuously.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The seed polymer particles used in the present invention are styrene-based or acrylic-based polymers which are conventionally known as seed polymers for seed polymerization. Non-crosslinked particles are preferred because they can increase the sphericity of the resulting polymer particles. These seed polymer particles can be obtained by soap-free polymerization, emulsion polymerization, non-aqueous precipitation polymerization, or the like. Further, the obtained fine particle polymer can be used as a seed polymer after being coarsened by a seed polymerization method.

The oil-soluble ethylenically unsaturated monomers used in the present invention include, for example, styrene monomers, (meth) acrylate monomers, alkyl vinyl ethers, vinyl ester monomers, N-alkyl-substituted (meth) acrylamide And nitrile monomers, polyfunctional monomers, and the like. Specific examples include those disclosed in JP-B-5-64964, column 4, lines 8 to 36. One or more of these monomers can be used.

The polymerization initiator used in the present invention is an oil-soluble polymerization initiator such as a peroxide-based initiator or an azo-based initiator. Some are disclosed in line 10. Further, at the time of polymerization, various surfactants, polymer protective colloids, or poorly water-soluble inorganic salts may be used in order to improve the dispersion stability of the polymer particles.

In the present invention, in order to add the seed polymer particle slurry stepwise or continuously, for example, a part of the seed polymer particle slurry is mixed with a monomer aqueous dispersion, and then the seed polymer particle slurry is added. There are a method of adding the remainder stepwise or continuously, and a method of adding the seed polymer particle slurry to the aqueous monomer dispersion stepwise or continuously. Further, during or after the addition of the seed polymer particle slurry stepwise or continuously, the monomer aqueous dispersion may be further added stepwise or continuously to carry out the polymerization.

In the present invention, in consideration of the particle size distribution of the seed polymer particles, in the stepwise addition, the number of divisions of the seed polymer particle slurry, the amount added in one operation, and the time interval for addition are defined. , And in continuous addition,
The standard deviation and the particle size distribution are controlled by specifying the time from the start to the end of the addition, the addition rate of the seed polymer particle slurry, and the concentration of the seed polymer particle slurry. Specifically, polymerization is performed several times while changing the factors of
Although polymer fine particles having a desired particle size distribution will be obtained, from several experimental results, to grasp the influence of each on the standard deviation and the particle size distribution, and simulate using this, Polymer fine particles having desired standard deviation and particle size distribution can be obtained by simpler operations.

The number of divisions of the seed polymer particle slurry to be added in the stepwise addition in the present invention is preferably at least two times, more preferably at least four times, in order to increase the standard deviation and increase the accuracy. From the viewpoint of simplicity of the operation, the number is preferably 50 or less, particularly preferably 16 or less. In addition, in the case of continuous addition, when an addition device or the like capable of precisely controlling the addition flow rate can be prepared, the particle size distribution pattern can be controlled very precisely.

The polymerization in the present invention is carried out by a conventional seed polymerization method in which a vinyl monomer is absorbed into fine particles made of a polymer such as styrene or (meth) acrylic polymer and then the polymerization is carried out, as disclosed in JP-B-57-24369. And the accelerated diffusion seed polymerization method described in JP-A-64-81810.

According to the polymerization method of the present invention, the existence probability of seed polymer particles having different swelling ratios is controlled, and a mixture of particles obtained without dividing and adding a seed polymer particle slurry is synthesized at once. You can think. In this method, the swelling ratio and the existence probability of the seed polymer particles can be delicately and independently controlled, so that either one of them can be controlled.
For example, by taking a small change in the swelling ratio and greatly changing the existence probability of the particles, it is possible to greatly change the particle size distribution while keeping the spread of the standard deviation to a minimum. More specifically, for example, using seed polymer particles that give a polymer particle having a bimodal particle size distribution when polymerization is performed without a split addition operation, a particle size distribution close to a normal distribution In the case of synthesizing the polymer particles, the amounts of the seed polymer particles and the oil-soluble ethylenically unsaturated monomer to be added are increased stepwise in the early stage of the addition and gradually decreased in the latter stage of the addition. Thus, by independently controlling the swelling ratio and the existence probability of the seed polymer particles, the standard deviation and the particle size distribution of the polymer fine particles can be freely controlled.

The production method of the present invention has an average particle diameter of 1 to 50 μm,
Standard deviation 0.18 to 2.4, particularly preferably used to obtain polymer fine particles having an average particle diameter of 2 to 30 μm, standard deviation of 0.19 to 2.0, the obtained polymer fine particles, for example, a gap holding material such as a spacer for a liquid crystal display device, It can be suitably used as a lubricant, a filler for liquid chromatography or gel permeation chromatography, a standard particle, a diagnostic agent and the like.

[0014]

EXAMPLES In the examples, "parts" means "parts by weight".

Reference Example (Production of seed polymer particles) 10 parts of polyvinylpyrrolidone (molecular weight: 40,000), Perex
A solution prepared by dissolving 3 parts of OT-P (manufactured by Kao Corporation, anionic surfactant) and 0.48 parts of azobisisobutyronitrile in 340 parts of methanol was heated to 60 ° C. under a nitrogen stream while stirring, Then, 32 parts of styrene was added, and the mixture was kept at the same temperature for 24 hours to obtain polymer particles. The average particle size of these particles is 1.60μ
m, the standard deviation of the particle size distribution was 0.045 μm.

Example 1 300 parts of ion-exchanged water and 0.8 part of sodium lauryl sulfate were added to 1.5 parts of the dry particles of the reference example and uniformly dispersed (dispersion A). 50 parts of styrene and divinylbenzene (purity 57
%) 100 parts of a monomer mixture consisting of 50 parts and 60 parts of ethanol
In addition, 600 parts of ion-exchanged water and 2 parts of sodium lauryl sulfate were mixed with 1 part of benzoyl peroxide and 1 part of benzoyl peroxide dissolved therein (dispersion B). To 30.2 parts of the dispersion A, 95.4 parts of the ultrasonically treated dispersion B was added, and the mixture was stirred at 40 ° C. for 1 hour (dispersion C). Subsequently, 60.5 parts of dispersion A and 95.4 parts of dispersion B subjected to ultrasonic treatment were added to dispersion C, and the mixture was stirred at 40 ° C. for 1 hour (dispersion D). To Dispersion D, 90.7 parts of Dispersion A and 95.4 parts of Ultrasonic Dispersion B were added, and the mixture was stirred at 40 ° C. for 1 hour (Dispersion E). To Dispersion E, 116.2 parts of Dispersion A and 95.4 parts of Dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 1 hour (Dispersion F). Next, the dispersion B 19 obtained by ultrasonically treating the dispersion F
0.7 parts was added and the mixture was stirred at 40 ° C. for 2 hours (dispersion liquid G).
Subsequently, 190.7 parts of ultrasonic dispersion-treated dispersion B was added to dispersion G, and the mixture was stirred at 40 ° C. for 2 hours (dispersion H). Next, polyvinyl alcohol (GH-17; saponification degree 86.5-
89 mol%, 3% aqueous solution of Nippon Synthetic Chemical Industry Co., Ltd. 3
After adding 00 parts, polymerization was carried out at 80 ° C. for 12 hours under a nitrogen stream while stirring. The obtained polymer fine particles were washed with ion-exchanged water and a solvent, then isolated and dried. The average particle size of the particles was 6.02 μm, and the standard deviation was 0.417 μm.

Example 2 Dispersion A was the same as in Example 1, and Dispersion B was 50 parts of methyl methacrylate and divinylbenzene (purity 57%).
%) 100 parts of a monomer mixture consisting of 50 parts and 60 parts of ethanol
Part A and 3 parts of benzoyl peroxide were dissolved in 600 parts of ion-exchanged water and 2 parts of sodium lauryl sulfate.
47.7 parts were added, and the mixture was stirred at 40 ° C for 30 minutes (dispersion liquid C).
Subsequently, 60.5 parts of dispersion A and 47.7 parts of dispersion B subjected to ultrasonic treatment were added to dispersion C, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion D). To Dispersion D, 90.7 parts of Dispersion A and 47.7 parts of Ultrasonic Dispersion B were added, and the mixture was stirred at 40 ° C. for 30 minutes (Dispersion E). To Dispersion E, 116.2 parts of Dispersion A and 47.7 parts of Dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (Dispersion F). Next, Dispersion B obtained by ultrasonically treating Dispersion F 190.7
The mixture was stirred at 40 ° C. for 2 hours (Dispersion G). Subsequently, 190.7 parts of the dispersion B subjected to ultrasonic treatment was added to the dispersion G,
The mixture was stirred at 40 ° C. for 2 hours (Dispersion H). Further, 190.8 parts of ultrasonically treated dispersion B was added to dispersion H, and the mixture was stirred at 40 ° C. for 2 hours (dispersion I). Next, polyvinyl alcohol was added to Dispersion I in the same manner as in Example 1, polymerization was performed by the same operation, and washing / isolation / drying was performed to obtain polymer fine particles. The average particle size of the particles was 6.04 μm, and the standard deviation was 0.209 μm.

Example 3 A dispersion A was the same as that in Example 1, and a dispersion B was a monomer mixture 100 composed of 30 parts of methyl methacrylate, 20 parts of ethylene glycol dimethacrylate, and 50 parts of divinylbenzene (purity: 57%). 60 parts of ethanol and 1 part of azobisisobutyronitrile were dissolved in 600 parts of ion-exchanged water, and 2 parts of sodium lauryl sulfate were mixed. Liquid B1
9.1 parts was added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion liquid C).
Subsequently, to dispersion C, 60.5 parts of dispersion A and 38.2 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion D). To Dispersion D, 90.7 parts of Dispersion A and 57.2 parts of Dispersion B which had been subjected to ultrasonic treatment were added, followed by stirring at 40 ° C. for 30 minutes (Dispersion E). To Dispersion E, 116.2 parts of Dispersion A and 76.3 parts of Dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (Dispersion F). Next, Dispersion B obtained by ultrasonically treating Dispersion F 190.7
The mixture was stirred at 40 ° C. for 2 hours (Dispersion G). Subsequently, 190.7 parts of the dispersion B subjected to ultrasonic treatment was added to the dispersion G,
The mixture was stirred at 40 ° C. for 2 hours (Dispersion H). Further, 190.8 parts of ultrasonically treated dispersion B was added to dispersion H, and the mixture was stirred at 40 ° C. for 2 hours (dispersion I). Next, polyvinyl alcohol was added to the dispersion I in the same manner as in Example 1, polymerization was carried out by the same operation, and washing / isolation / drying was performed to obtain polymer fine particles. The average particle size of the particles was 6.00 μm, and the standard deviation was 0.193 μm.

Example 4 The same dispersion as in Example 1 was used as dispersion A, and 100 parts of a monomer mixture composed of 40 parts of styrene, 10 parts of methacrylonitrile, and 50 parts of divinylbenzene (purity: 57%) was used as dispersion B. A mixture of 60 parts of ethanol and 1 part of benzoyl peroxide mixed with 600 parts of ion-exchanged water and 2 parts of sodium lauryl sulfate was used. Was added and stirred at 40 ° C. for 30 minutes (dispersion C). Subsequently, 40.3 parts of the dispersion A and 50.9 parts of the dispersion B subjected to ultrasonic treatment were added to the dispersion C, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion D). To Dispersion D, 60.5 parts of Dispersion A and 76.3 parts of Ultrasonic Dispersion B were added and stirred at 40 ° C. for 30 minutes (Dispersion E). To Dispersion E, 80.6 parts of Dispersion A and 101.7 parts of Ultrasonic Dispersion B were added, and the mixture was stirred at 40 ° C. for 30 minutes (Dispersion F). To Dispersion F, 100.7 parts of Dispersion A and 127.2 parts of Ultrasonic Dispersion B were added, and the mixture was stirred at 40 ° C. for 30 minutes (Dispersion G). Next, 190.7 parts of ultrasonically treated dispersion B was added to dispersion G, and the mixture was stirred at 40 ° C. for 2 hours (dispersion H). Subsequently, the dispersion liquid B 19 obtained by ultrasonically treating the dispersion liquid H was used.
0.8 parts was added and the mixture was stirred at 40 ° C. for 2 hours (dispersion liquid I).
Next, 300 parts of a 1% aqueous solution of polyvinylpyrrolidone (molecular weight of 40,000) was added to Dispersion I, and polymerization was carried out in the same manner as in Example 1, followed by washing / isolation / drying to obtain polymer fine particles. The average particle size of these particles is 5.95 μm, and the standard deviation is 0.328 μm
Met.

Example 5 A dispersion A was the same as in Example 1, and a dispersion B was a monomer mixture comprising 10 parts of methyl acrylate, 10 parts of acrylonitrile, and 80 parts of divinylbenzene (purity 81%).
A mixture of 60 parts of ethanol and 7 parts of benzoyl peroxide dissolved in 00 parts of ion-exchanged water of 600 parts and sodium lauryl sulfate of 2 parts was used. 6 parts were added and stirred at 40 ° C. for 30 minutes (dispersion C). Subsequently, 16.8 parts of the dispersion A and 21.2 parts of the dispersion B subjected to ultrasonic treatment were added to the dispersion C, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion D). To dispersion D, 25.2 parts of dispersion A and 31.8 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion E). To dispersion E, 33.6 parts of dispersion A and 42.4 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion F). To Dispersion F, 42.0 parts of Dispersion A and 53.0 parts of Dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (Dispersion G). To Dispersion G, 50.4 parts of Dispersion A and 63.6 parts of Dispersion B which had been subjected to ultrasonic treatment were added, followed by stirring at 40 ° C. for 30 minutes (Dispersion H). To dispersion H, 58.8 parts of dispersion A and 74.2 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion I). To Dispersion I, 67.1 parts of Dispersion A and 84.8 parts of Dispersion B which had been subjected to ultrasonic treatment were added, followed by stirring at 40 ° C. for 30 minutes (Dispersion J). Next, 193.7 parts of Dispersion B subjected to ultrasonic treatment was added to Dispersion J, and the mixture was stirred at 40 ° C. for 2 hours (Dispersion K). Subsequently, the dispersion liquid B 19 obtained by ultrasonically treating the dispersion liquid H was used.
3.7 parts were added and stirred at 40 ° C. for 2 hours (dispersion liquid L).
Next, polyvinylpyrrolidone was added to the dispersion L in the same manner as in Example 4, polymerization was carried out in the same manner, and washing / isolation / drying was performed to obtain polymer fine particles. The average particle size of these particles is 6.05μ
m, and the standard deviation was 0.428 μm.

Example 6 150 parts of ion-exchanged water, 0.5 part of sodium lauryl sulfate, and 10 parts of acetone were added to 1.5 parts of the dry particles of the reference example, and uniformly dispersed (dispersion A). Next, 136.8 parts of water was added to t-butyl peroxy 2-ethylhexanoate (Nippon Yushi Co., Ltd.)
3 parts perbutyl O), sodium lauryl sulfate 0.5
Was added and the mixture was sonicated (dispersion B). This dispersion B
Was added to Dispersion A and stirred at 30 ° C. for 12 hours. After stirring for 12 hours, the acetone was removed by vacuum evaporation (dispersion C).

50 parts of styrene and divinylbenzene (purity 81
%) Of 50 parts of a monomer mixture, 600 parts of ion-exchanged water and 2 parts of sodium lauryl sulfate were mixed (dispersion D). Dispersion C3 Dispersion D8 obtained by ultrasonically treating 0.23 parts
7.1 parts was added and the mixture was stirred at 40 ° C. for 1.5 hours (Dispersion E). Subsequently, 60.5 parts of dispersion C and 87.1 parts of dispersion D which had been subjected to ultrasonic treatment were added to dispersion E, and the mixture was stirred at 40 ° C. for 1.5 hours (dispersion F). To Dispersion F, 90.7 parts of Dispersion C and 87.1 parts of Dispersion D subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 1.5 hours (Dispersion G). To Dispersion G, 116.2 parts of Dispersion C and 87.1 parts of Dispersion D subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 1.5 hours (Dispersion H). Next, 174.1 parts of Dispersion D subjected to ultrasonic treatment was added to Dispersion H, and the mixture was stirred at 40 ° C. for 3 hours (Dispersion I). Subsequently, the dispersion D obtained by subjecting the dispersion I to ultrasonic treatment is
79.5 parts was added, and the mixture was stirred at 40 ° C. for 3 hours (dispersion liquid J).
Next, polyvinyl alcohol was added to Dispersion J in the same manner as in Example 1, polymerization was carried out by the same operation, and washing / isolation / drying was performed to obtain polymer fine particles. The average particle size of these particles is 5.90μ
m, the standard deviation was 0.486 μm.

Example 7 A dispersion A was the same as in Example 1, and a dispersion B was a monomer mixture comprising 10 parts of methyl acrylate, 10 parts of methacrylonitrile, and 80 parts of divinylbenzene (81% purity).
A mixture prepared by dissolving 60 parts of ethanol and 1 part of benzoyl peroxide in 100 parts of a mixture of 600 parts of ion-exchanged water and 2 parts of sodium lauryl sulfate was used. Was added and stirred at 40 ° C. for 30 minutes (dispersion C). Subsequently, 4.4 parts of Dispersion A and 8.4 parts of Ultrasonic Dispersion B were added to Dispersion C, and the mixture was stirred at 40 ° C. for 30 minutes (Dispersion D). To Dispersion D, 6.7 parts of Dispersion A and 12.6 parts of Ultrasonic Dispersion B were added, and the mixture was stirred at 40 ° C. for 30 minutes (Dispersion E). To Dispersion E, 8.9 parts of Dispersion A and 16.8 parts of Dispersion B which had been subjected to ultrasonic treatment were added, followed by stirring at 40 ° C. for 30 minutes (Dispersion F). To dispersion F, 11.1 parts of dispersion A and 21.0 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion G). To dispersion G, 13.3 parts of dispersion A and 25.2 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion H). To Dispersion H, 15.6 parts of Dispersion A and 29.5 parts of Dispersion B subjected to ultrasonic treatment were added, followed by stirring at 40 ° C. for 30 minutes (Dispersion I). To dispersion I, 17.8 parts of dispersion A and 33.7 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion J). To Dispersion J, 20.0 parts of Dispersion A and 37.9 parts of Ultrasonic Dispersion B were added, and the mixture was stirred at 40 ° C. for 30 minutes (Dispersion K). To dispersion K, 22.2 parts of dispersion A and 42.1 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion L). To Dispersion L, 24.5 parts of Dispersion A and 46.3 parts of Dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (Dispersion M). To dispersion M, 26.7 parts of dispersion A and 50.5 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion N). To Dispersion N, 28.9 parts of Dispersion A and 54.7 parts of Dispersion B which had been subjected to ultrasonic treatment were added, followed by stirring at 40 ° C. for 30 minutes (Dispersion O). To dispersion O, 31.1 parts of dispersion A and 58.9 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion P). To dispersion P, 33.3 parts of dispersion A and 63.1 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion Q). To dispersion Q, 35.6 parts of dispersion A and 67.3 parts of dispersion B subjected to ultrasonic treatment were added, and the mixture was stirred at 40 ° C. for 30 minutes (dispersion R). Subsequently, 190.8 parts of ultrasonically treated dispersion B was added to dispersion R, and the mixture was stirred at 40 ° C. for 2 hours (dispersion S). Next, polyvinylpyrrolidone was added to the dispersion S in the same manner as in Example 4, polymerization was carried out by the same operation, and washing / isolation / drying was performed to obtain polymer fine particles. The average particle size of the particles was 6.08 μm, and the standard deviation was 0.901 μm.

Example 8 300 parts of ion-exchanged water and 2.88 parts of sodium lauryl sulfate were added to 1.71 parts of the dry particles of the reference example and uniformly dispersed to prepare a seed polymer particle dispersion. 50 parts of styrene, 80 parts of divinylbenzene (purity 57%) and acrylonitrile
75 parts of ethanol in 150 parts of a monomer mixture consisting of 20 parts
Then, 750 parts of ion-exchanged water and 6.75 parts of sodium lauryl sulfate were added to a solution prepared by dissolving 8.34 parts of benzoyl peroxide and benzoyl peroxide, and uniformly mixed and dispersed to prepare a monomer / polymerization initiator dispersion.

Ultrasonicated monomer / polymerization initiator dispersion
To 198 parts, 30.5 parts of a seed polymer particle dispersion was added and stirred at 40 ° C. The time at which this addition was performed was set to 0 minutes, and after 30 minutes / 60 minutes / 90 minutes after stirring at 40 ° C., 61.0 parts / 91.4 parts / 121.
9 copies were added. After 120 minutes / 240 minutes / 360 minutes, 264 parts of the remaining ultrasonically treated monomer / polymerization initiator dispersion was added. After 480 minutes, polyvinyl alcohol (GH-17) and polyvinylpyrrolidone (BASF) are added to the above dispersion mixture.
Aqueous solution containing 3.7% each of LUVISKOL K-30)
324 parts was added, and polymerization was carried out at 80 ° C. for 14 hours under a nitrogen stream while stirring. The obtained polymer fine particles were washed with ion-exchanged water and a solvent, then isolated and dried. The particles had an average particle size of 6.62 μm and a standard deviation of 0.271 μm.

Example 9 A seed polymer particle dispersion and a monomer / polymerization initiator dispersion were prepared in the same manner as in Example 8, except that the amount of the seed polymer particles was changed to 2.02 parts. Ultrasonicated monomer / polymerization initiator dispersion
To 330 parts, a seed polymer particle dispersion was added at a constant flow rate of 3.37 mL / min for 93 minutes while stirring at 40 ° C. The addition start time was set to 0 minute, and after 120 minutes / 240 minutes / 360 minutes, 220 parts of the remaining monomer / polymerization initiator dispersion subjected to ultrasonic treatment was added. After 480 minutes, polymerization was carried out in the same manner as in Example 8, followed by washing / isolation / drying to obtain polymer fine particles. The particles had an average particle size of 6.12 μm and a standard deviation of 0.252 μm.

Comparative Example 1 Dispersions A and B were prepared in the same manner as in Example 1. Dispersion A, which had been subjected to ultrasonic treatment, was added to 302.3 parts of Dispersion A four times at an interval of 2 hours, each of 190.8 parts while stirring at 40 ° C. Next, polyvinyl alcohol was added to this dispersion in the same manner as in Example 1, polymerization was carried out in the same manner, and washing / isolation / drying was performed to obtain polymer fine particles. The average particle size of the particles was 6.01 μm, and the standard deviation was 0.174 μm.

Comparative Example 2 Dispersions C and D were prepared in the same manner as in Example 6. While stirring 302.3 parts of Dispersion C at 40 ° C., 702 parts of Ultrasonic Dispersion D was added. After stirring for 12 hours, polyvinyl alcohol was added to the dispersion in the same manner as in Example 1, polymerization was performed by the same operation, and washing / isolation / drying was performed to obtain polymer fine particles. The average particle size of the particles was 5.87 μm, and the standard deviation was 0.175 μm.

Comparative Example 3 To a mixture of 20 parts of styrene, divinylbenzene (purity: 57%) and 1 part of benzoyl peroxide, 900 parts of a 1% aqueous solution of polyvinyl alcohol (GH-17) was added, and a homogenizer (specialized machine) (TK-Homomixer), emulsified (8000 rpm, 5 minutes), and then stirred at 80 ° C. under a nitrogen stream.
For 12 hours, followed by washing / isolation / drying in the same manner as in Example 1 to obtain polymer fine particles. The average particle size of these particles is 7.15
μm, the standard deviation was 2.86 μm.

[0030]

According to the production method of the present invention, the particle size distribution and standard deviation of the obtained polymer fine particles can be controlled, and the particle size distribution of the polymer fine particles obtained by the seed polymerization method and the suspension polymerization method can be controlled. Polymer fine particles having a distribution located between them and polymer fine particles having a desired particle size distribution can be easily obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsuo Takano 1334 Minato 1334 Minato, Wakayama City, Wakayama Prefecture Inventor Yoshikazu Morii 1334 Minato 1 Minato Wakayama City, Wakayama Prefecture Research Institute, Kao Corporation (72) Inventor Shunji Kojima 1334 Minato, Wakayama-shi, Wakayama Prefecture F-term in the Kao Research Institute (reference) 4J011 JA03 JA13 JB08 JB16 JB26 PA65 PA68 PA69 PB06

Claims (3)

[Claims] An oil-soluble ethylenically unsaturated monomer is mixed with an aqueous dispersion of seed polymer particles and an oil-soluble ethylenically unsaturated monomer, and the oil-soluble ethylenically unsaturated monomer is absorbed by the seed polymer particles. When polymerizing in the presence of a soluble polymerization initiator to obtain polymer fine particles, a mixture of the seed polymer particles dispersed in the aqueous dispersion medium and the oil-soluble ethylenically unsaturated monomer aqueous dispersion is converted into an aqueous dispersion medium. A method for producing polymer fine particles, which is performed by adding dispersed seed polymer particles stepwise or continuously. 2. After mixing a part of the seed polymer particles dispersed in the aqueous dispersion medium and the aqueous dispersion of the oil-soluble ethylenically unsaturated monomer, the remaining part of the seed polymer particles dispersed in the aqueous dispersion medium is mixed. The production method according to claim 1, wherein the addition is carried out continuously or continuously. 3. During or after the stepwise or continuous addition of the seed polymer particles dispersed in the aqueous dispersion medium,
The method according to claim 1 or 2, wherein the polymerization is carried out by adding a stepwise or continuous addition of an aqueous dispersion of an oil-soluble ethylenically unsaturated monomer.