JP5630266B2 - Method for producing polymer fine particles - Google Patents

Description

  The present invention relates to a method for producing polymer fine particles. More specifically, the present invention relates to a method for producing micron-sized polymer fine particles having a narrow particle size distribution and a uniform particle size by a dispersion polymerization method, using a specific dispersion stabilizer, with good productivity. About.

When a dispersion polymerization method is employed in which a vinyl monomer is polymerized in a solvent that dissolves the vinyl monomer in the presence of a dispersion stabilizer but does not substantially dissolve the resulting polymer. It is known that micron-sized polymer particles having a relatively narrow particle size distribution can be obtained.
In the dispersion polymerization method, a hydrophilic solvent or a non-hydrophilic solvent is used as a polymerization solvent. When performing dispersion polymerization in a hydrophilic solvent, polyvinyl pyrrolidone, polyethylene glycol, or the like has been conventionally used as a dispersion stabilizer. Also known is a dispersion polymerization method using a macromonomer having a radical polymerizable functional group at the end of a polyethylene oxide chain as a dispersion stabilizer (see Patent Document 1).
However, in the above dispersion polymerization technique, it is necessary to use a relatively large amount of a dispersion stabilizer in order to produce polymer fine particles having a target particle size and particle size distribution. In addition, a large amount of dispersion stabilizer remains in the resulting polymer fine particles, which tends to adversely affect the performance of the polymer fine particles. Moreover, the dispersion stabilization by the dispersion stabilizer is insufficient, and aggregation is likely to occur between the produced polymer fine particles. Furthermore, in the conventional dispersion polymerization technique described above, it is necessary to perform polymerization at a low concentration of the vinyl monomer in order to prevent aggregation between polymer fine particles generated by the polymerization, so that productivity is low. .

  In view of the above, the present inventors have studied to develop a method capable of smoothly producing micron-sized polymer fine particles having excellent monodispersibility by preventing the polymer fine particles from aggregating during dispersion polymerization. Has been repeated. As a result, the present inventors conducted dispersion polymerization using a macromonomer having a carboxyl group and having a vinylidene-type unsaturated bond at the molecular chain end as a dispersion stabilizer. It has been found that polymer fine particles having excellent monodispersibility can be obtained without causing aggregation (see Patent Document 2).

Micron-sized polymer fine particles with a narrow particle size distribution and a uniform particle size are used in applications such as light diffusing agents, anti-glare agents (matting agents), anti-blocking agents, and spacers. In any application, it is required to cope with high definition. Along with this, there are many cases where polymer fine particles having a smaller particle diameter are required.
From this point, the present inventors further examined the dispersion polymerization method of Patent Document 2 described above. As a result, when the dispersion stabilizer (macromonomer) described in Patent Document 2 is used, the polymer fine particles obtained tend to be larger than 2 μm, and polymer fine particles having a smaller particle size are obtained. In order to obtain it, it is necessary to increase the amount of the dispersion stabilizer (macromonomer) used, and it has been found that there is room for improvement in terms of preventing deterioration of the performance of the resulting polymer fine particles and suppressing cost increase. .

JP-A-9-157307 JP 2004-149469 A

An object of the present invention is to produce high-quality polymer fine particles having a narrow particle size distribution and having a smaller particle size than that of polymer fine particles obtained by conventional dispersion polymerization methods, and having a uniform particle size. It is to provide a method for producing smoothly without causing aggregation or the like in the meantime.
Furthermore, the object of the present invention is to reduce the amount of the dispersion stabilizer used in the conventional method and to prevent the adverse effect on the polymer fine particles due to the heavy use of the dispersion stabilizer. It is an object of the present invention to provide a method for producing excellent, high-quality fine polymer particles smoothly and with high productivity.
Another object of the present invention is to provide polymer fine particles by dispersion polymerization having the above-described excellent characteristics.

  The present inventors have repeatedly studied to achieve the above-described object. As a result, it was found that a macromonomer having a carboxyl group and an ethylenically unsaturated group in the middle of the molecular chain exhibits an extremely excellent dispersion stabilizing effect. Therefore, when the macromonomer (dispersion stabilizer) was used for dispersion polymerization in a hydrophilic solvent using the macromonomer as a dispersion stabilizer, the particle size distribution was narrow due to the very small amount of the macromonomer (dispersion stabilizer) used. It has been found that uniform-sized polymer fine particles can be produced smoothly without causing aggregation or the like between the polymer fine particles. Moreover, the polymer fine particles obtained thereby have a smaller particle size while maintaining a narrow particle size distribution as compared with the case where the above-described conventional dispersion stabilizer is used, and there is a demand for the above-described recent high definition. It was found to match. Furthermore, when using a dispersion stabilizer comprising the above-mentioned macromonomer having a carboxyl group and an ethylenically unsaturated group in the middle of the molecular chain, the present inventors have achieved excellent dispersion stabilization performance in an aqueous solvent. It has been found that since it is not necessary to reduce the concentration of the vinyl monomer, it is possible to produce polymer fine particles having a desired uniform size with high productivity. Further, since only a small amount of the macromonomer is used as a dispersion stabilizer, it is not necessary to remove excess dispersion stabilizer by washing or the like, as in a polymer fine particle dispersion using a conventional dispersion stabilizer, It has also been found that polymer resin fine particles having excellent physical properties and handleability can be produced with higher productivity and lower cost.

Further, the present inventors have described that the macromonomer used as a dispersion stabilizer includes an epoxy group and an ethylenically unsaturated group in a part of the carboxyl group of the polymer (A) having a carboxyl group in the middle of the molecular chain. The macromonomer obtained by the addition reaction of the compound (α) having an excellent dispersion stabilization performance, ease of production of the macromonomer, and a large degree of freedom in designing the macromonomer From the point of view, it was found preferable.
Furthermore, the present inventors, in the above-described macromonomer used as a dispersion stabilizer, when the content of ethylenically unsaturated groups and the content of carboxyl groups are in a specific range, the dispersion stabilization performance is more excellent Furthermore, it has been found that polymer fine particles having a narrower particle size distribution can be obtained, and that polymer fine particles having a smaller particle size can be obtained.
The present inventors have found that a (meth) acryloyl group is preferable as the ethylenically unsaturated group of the macromonomer from the viewpoints of dispersion stabilization performance, reduction in particle size, and the like.

In addition, the present inventors used a macromonomer having a carboxyl group and an ethylenically unsaturated group in the middle of the molecular chain as a dispersion stabilizer to hydrolyze the vinyl monomer as a vinyl monomer. Polymer fine particles having hydrolyzable silyl groups are produced using a vinyl monomer containing at least part of a vinyl monomer having a polymerizable silyl group, and hydrolyzable silyl groups in the polymer fine particles are hydrolyzed. Thus, it was found that crosslinked polymer fine particles having excellent strength, deformation resistance (particle shape maintaining property), heat resistance, handleability, fluidity, solvent resistance and the like can be obtained by causing a crosslinking reaction.
Further, the present inventors used a macromonomer having a carboxyl group and an ethylenically unsaturated group in the middle of a molecular chain as a dispersion stabilizer, and in conducting dispersion polymerization of a vinyl monomer, Even when a vinyl monomer containing at least a part of a polyfunctional vinyl monomer having two or more unsaturated groups is used, strength, deformation resistance (particle shape maintenance), heat resistance, handleability, flow It was found that crosslinked polymer fine particles having excellent properties and solvent resistance can be obtained.
Furthermore, the present inventors have developed a polymer fine particle obtained by dispersing and polymerizing a vinyl monomer using a macromonomer having a carboxyl group and an ethylenically unsaturated group in the middle of the molecular chain as a dispersion stabilizer. It is excellent in strength, deformation resistance (particle shape maintenance), heat resistance, handleability, fluidity, solvent resistance, etc. by polymerizing after absorbing vinyl monomers including functional vinyl monomers. The inventors have found that crosslinked polymer fine particles can be obtained, and have completed the present invention based on these various findings.

That is, the present invention is shown below.
1. A step of polymerizing a vinyl monomer in the presence of a dispersion stabilizer in a hydrophilic solvent that dissolves the vinyl monomer and the dispersion stabilizer but does not dissolve the resulting polymer (hereinafter referred to as “first” A method of producing polymer fine particles, comprising a polymerization step),
The dispersion stabilizer contains a polymer containing a macromonomer having a carboxyl group and an ethylenically unsaturated group in the middle of a molecular chain, and the polymer has an average of 0.2 to 1.74 per molecule. A method for producing polymer fine particles, which has one ethylenically unsaturated group .
2. The macromonomer is a polymer obtained by addition-reacting a compound having an epoxy group and an ethylenically unsaturated group to a part of the carboxyl group of the polymer (A) having a carboxyl group in the middle of the molecular chain. 2. The method for producing polymer fine particles as described in 1 above.
3. 3. The method for producing polymer fine particles as described in 2 above, wherein the polymer (A) is a polymer produced by emulsion polymerization.
4). The said polymer in the said dispersion stabilizer is manufacture of the polymer fine particle of any one of said 1-3 which has an average of 0.2-1.6 ethylenically unsaturated groups per molecule. Method.
5. The said dispersion stabilizer contains the polymer containing the said macromonomer, The average value of content of the carboxyl group in this polymer is 1-9 meq / g. A method for producing coalesced fine particles.
6). 6. The method for producing polymer fine particles according to any one of 1 to 5, wherein the macromonomer contains a (meth) acryloyl group.
7). 7. The polymer fine particles according to any one of 1 to 6 above, wherein the vinyl monomer contains at least a vinyl monomer having a hydrolyzable silyl group and produces fine particles comprising a polymer having a hydrolyzable silyl group. Manufacturing method.
8). The method according to 7 above, further comprising a step of hydrolyzing and condensing a hydrolyzable silyl group in the polymer as described in 7 above (hereinafter referred to as “hydrolysis step”), and producing fine particles comprising a crosslinked polymer. A method for producing polymer fine particles.
9. 8. The method for producing polymer fine particles according to any one of 1 to 7, wherein the vinyl monomer contains at least a polyfunctional vinyl monomer having two or more ethylenically unsaturated groups.
10. Furthermore, the polymer fine particles obtained by the production method according to any one of 1 to 6 described above are polymerized after the vinyl monomer containing the polyfunctional vinyl monomer is absorbed (hereinafter referred to as “second polymerization step”). The method for producing polymer fine particles according to any one of 1 to 6 above, wherein the polymer fine particles are produced.
11. The polymer fine particles obtained by any one of the production methods 1 to 10 above, having a volume average particle size of 0.7 to 2.0 μm and a coefficient of variation of particle size of 20% or less. Polymer fine particles.

In the present specification, “(meth) acryl” means acryl and / or methacryl, and “(meth) acrylate” means acrylate and / or methacrylate.
Carboxyl group included in the "macromonomer" is, -COOH and / or -COO ^- means.
Moreover, the weight average molecular weight (Mw) and number average molecular weight (Mn) of a polymer are the standard polystyrene conversion values obtained using the gel permeation chromatography (GPC) on the conditions in [Example] mentioned later. .

According to the method of the present invention, polymer fine particles having a small particle diameter and a small variation in particle diameter can be efficiently produced by the extremely excellent dispersion stabilization performance of a specific macromonomer in the reaction system. . And by using a very small amount of macromonomer, it is possible to maintain excellent dispersion stability of fine polymer particles with a narrow particle size distribution and uniform size without causing aggregation between the polymer particles. However, it can be manufactured smoothly, with good productivity and at low cost.
As the macromonomer, a polymer obtained by adding a compound having an epoxy group and an ethylenically unsaturated group to a part of the carboxyl group of the polymer (A) having a carboxyl group in the middle of the molecular chain was used. In this case, the desired polymer fine particles can be produced more smoothly from the viewpoint of excellent dispersion stabilization performance and the like. Such a macromonomer has a high degree of freedom in structural design and is easily manufactured.

When a vinyl monomer containing at least a vinyl monomer having a hydrolyzable silyl group is used in the first polymerization step, and then the hydrolyzable silyl group in the polymer is hydrolyzed and condensed in the hydrolysis step. For smooth cross-linked polymer particles with excellent strength, deformation resistance (particle shape maintenance), heat resistance, handleability, fluidity, solvent resistance, etc., narrow particle size distribution and uniform particle size Can be obtained.
In the first polymerization step, when a vinyl monomer containing at least a polyfunctional vinyl monomer having two or more ethylenically unsaturated groups is used, strength, deformation resistance (particle shape maintaining property), Crosslinked polymer fine particles having excellent heat resistance, handleability, fluidity, solvent resistance and the like, narrow particle size distribution and uniform particle size can be obtained smoothly.
Furthermore, in the first polymerization step, preferably, after producing fine particles made of an uncrosslinked polymer, when subjected to the second polymerization step, strength, deformation resistance (particle shape maintaining property), heat resistance, handling Crosslinked polymer fine particles having excellent properties, fluidity, solvent resistance and the like, narrow particle size distribution and uniform particle size can be obtained smoothly.

It is an image of magnification 2,000 times which imaged polymer fine particles (PA-1) obtained in Example 1 with FE-SEM. It is an image of magnification 12,000 times which imaged polymer fine particle (PA-1) obtained in Example 1 with FE-SEM. It is the image which the bridge | crosslinking polymer microparticles | fine-particles (PC-1) obtained in Example 11 image | photographed with FE-SEM (image before being immersed in methyl ethyl ketone). It is the image image | photographed by FE-SEM, after immersing the crosslinked polymer fine particle (PC-1) obtained in Example 11 in methyl ethyl ketone for 24 hours. It is the image which the bridge | crosslinking polymer microparticles | fine-particles (PC-13) obtained in Example 23 image | photographed with FE-SEM (image before being immersed in methyl ethyl ketone). It is the image image | photographed by FE-SEM, after immersing the crosslinked polymer fine particle (PC-13) obtained in Example 23 in methyl ethyl ketone for 24 hours.

The present invention is described in detail below.
The present invention is a method for producing polymer fine particles by a method including a first polymerization step using a dispersion polymerization method. More specifically, the present invention uses a dispersion stabilizer containing a macromonomer having a carboxyl group and an ethylenically unsaturated group in the middle of a molecular chain, and in the presence thereof, the vinyl monomer is converted into the vinyl monomer. And a method for producing polymer fine particles comprising a step of polymerizing in a hydrophilic solvent that dissolves the dispersion stabilizer but does not dissolve the polymer to be produced (first polymerization step). In this invention, you may perform a hydrolysis process, a separation process, a refinement | purification process, another polymerization process, etc. as needed after a 1st polymerization process.
In the first polymerization step according to the present invention, a hydrophilic solvent is used as the polymerization solvent. Therefore, the fine particles made of the polymer produced in this step are dispersed in the polymerization solvent containing the hydrophilic solvent.

In the present invention, a hydrophilic solvent is used as the polymerization solvent. Although the said hydrophilic solvent melt | dissolves the vinyl monomer and dispersion stabilizer which are mentioned later, if it is a compound which does not melt | dissolve the polymer to produce | generate, it will not specifically limit. As the hydrophilic solvent, a hydrophilic organic solvent (a hydrophilic organic solvent not containing water) or a mixed solvent of a hydrophilic organic solvent and water is used. At that time, as the hydrophilic organic solvent, those having a solubility in water at 20 ° C. of 5 g / 100 ml or more are preferably used.
Specific examples of the hydrophilic organic solvent include monoalcohols such as methanol, ethanol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, sec-butyl alcohol, and tetrahydrofurfuryl alcohol; ethylene glycol Polyhydric alcohols such as glycerin and diethylene glycol; ether alcohols such as methyl cellosolve, cellosolve, isopropylpyro cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether; acetone, Ketones such as methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; Ethers such as emissions; dimethylformamide, and dimethyl sulfoxide. Only one type of hydrophilic organic solvent may be used, or two or more types may be used in combination.

In the first polymerization step, the hydrophilic solvent is appropriately selected from the hydrophilic organic solvents described above according to the type of vinyl monomer used in the polymerization, the type of polymer to be generated, and the like. use.
Among these, as the hydrophilic organic solvent, lower alcohols such as methanol, ethanol and isopropyl alcohol are preferable. By using these alcohols, the dispersion stabilizing action of the dispersion stabilizer containing a specific macromonomer can be effectively exhibited, and polymer fine particles having a small particle diameter can be stably produced.

In the first polymerization step according to the present invention, when polymerization is performed in a hydrophobic solvent by conducting dispersion polymerization of a vinyl monomer in the presence of a dispersion stabilizer containing a specific macromonomer in a hydrophilic solvent. As compared with the above, it is possible to easily and smoothly control the particle diameter, particle size distribution, molecular weight and the like of the polymer fine particles to be generated while maintaining good polymerization stability.
In the present invention, the hydrophilic solvent is preferably a mixed solvent containing water and alcohol, and among them, a mixture comprising water and at least one selected from lower alcohols such as methanol, ethanol, isopropyl alcohol, and the like. A solvent is more preferable. When using a mixed solvent of water and the above alcohol as the hydrophilic solvent, by adjusting the mixing ratio of water and alcohol according to the type and composition of the vinyl monomer, The particle size, particle size distribution, molecular weight, etc. can be easily controlled. In addition, the risk of ignition, explosion, etc. can be reduced, and the burden on the environment is small.
In particular, as a hydrophilic solvent, a mixed solvent of water and methanol, of which a mixed solvent having a water: methanol mass ratio of 10:90 to 50:50, more preferably 20:80 to 40:60, is used. This is more preferable because polymer fine particles having a smaller diameter and a narrow particle size distribution can be produced smoothly.

  Note that a part of the hydrophilic solvent used in the first polymerization step may be replaced with a hydrophobic solvent having a solubility in water at 20 ° C. of less than 5 g / 100 ml. In this case, the ratio of the hydrophobic solvent is preferably 30% by mass or less, more preferably 15% by mass or less, and still more preferably 5% by mass or less with respect to the total amount of the solvent. When the content ratio of the hydrophobic solvent exceeds 30% by mass, the particle size distribution of the generated particles may be widened or aggregates may be generated in the first polymerization step.

In the first polymerization step according to the present invention, as a dispersion stabilizer at the time of dispersion polymerization of a vinyl monomer, a macromonomer having a carboxyl group and an ethylenically unsaturated group in the middle of the molecular chain (hereinafter referred to as “macromonomer (Ma)”). And also a dispersion stabilizer. The content ratio of the macromonomer (Ma) in this dispersion stabilizer is preferably 20 to 100% by mass, more preferably 50 to 100% by mass. When there is too little content of a macromonomer (Ma), the effect of this invention may not fully be acquired.
The dispersion stabilizer may contain other polymer. That is, the dispersion stabilizer can be a polymer composition (a mixture composed of a polymer) composed of a macromonomer (Ma) and another polymer. When the said dispersion stabilizer contains another polymer, the content rate of a macromonomer (Ma) becomes like this. Preferably it is 10-100 mass% with respect to all the polymers, More preferably, it is 30-100 mass%.
Examples of other polymers include polymers having a functional group such as a carboxyl group, a hydroxyl group, an amide group, a pyrrolidone group, and a morpholine group.
The dispersion stabilizer may comprise a macromonomer (Ma) or a polymer composition and an additive that does not inhibit the dispersion polymerization of the vinyl monomer, but the dispersion stabilizer in the present invention. Contains a polymer containing a macromonomer having a carboxyl group and an ethylenically unsaturated group in the middle of the molecular chain, and the polymer has an average of 0.2 to 1.74 ethylenic molecules per molecule. Has an unsaturated group .

The macromonomer (Ma) is Ru polymer der having a middle carboxyl group and an ethylenically unsaturated group of the molecular chain. In this macromonomer (Ma), the carboxyl group and ethylenically unsaturated group contained are not the ends of the molecular chain (polymer chain) constituting the macromonomer (Ma) but the molecular chain (polymer). At least in the middle of the chain).

Examples of the group having an ethylenically unsaturated group contained in the macromonomer (Ma) include a (meth) acryloyl group, an allyl group, an isopropenyl group, and a styryl group. The macromonomer (Ma) can have one or more of these groups. Moreover, the macromonomer which has an ethylenically unsaturated group in the middle and the terminal of a molecular chain can also be used as said macromonomer (Ma).
The group having an ethylenically unsaturated group is preferably a (meth) acryloyl group. When the macromonomer (Ma) having a carboxyl group and a (meth) acryloyl group is used in the middle of the molecular chain, the reactivity and dispersion stabilization performance of the vinyl monomer can be improved. And, by using a smaller amount of the dispersion stabilizer containing the macromonomer (Ma), the fine particle size distribution is narrow and the fine polymer particles having a uniform size can be stably stabilized without causing aggregation between the polymer particles. Can be manufactured.

  Further, the ethylenically unsaturated group contained in the macromonomer (Ma) may be directly bonded in the middle of the molecular chain of the macromonomer (Ma), or may be predetermined in the middle of the molecular chain of the macromonomer (Ma). You may couple | bond together in a suspended state through the coupling group. Furthermore, these two coupling types may be mixed.

  On the other hand, the carboxyl group contained in the macromonomer (Ma) is present at least in the middle of the molecular chain and may be present both in the middle and at the end of the molecular chain. Moreover, this carboxyl group may be directly bonded in the middle of the molecular chain of the macromonomer (Ma), or may be bonded in a suspended state via a predetermined bonding group in the middle of the molecular chain of the macromonomer (Ma). May be. Furthermore, these two coupling types may be mixed.

The content of the carboxyl group contained in the middle of the molecular chain of the macromonomer (Ma) is preferably 1 to 9 meq, more preferably 1.5 to 5 meq per 1 g of the macromonomer (Ma).
If the carboxyl group content in the macromonomer (Ma) is too small, the dispersion stabilizing performance of the macromonomer (Ma) tends to be lowered, whereas if the carboxyl group content is too large, the particle size distribution of the polymer fine particles May become wider and become uneven in size.

The carboxyl group that the macromonomer (Ma) has in the middle of the molecular chain is preferably neutralized with a base. The carboxyl group is dissociated into a carboxyl anion in a hydrophilic solvent by neutralization to cause electrostatic repulsion, thereby further improving the dispersion stabilization performance of the dispersion stabilizer containing the macromonomer (Ma). Aggregation between the polymer fine particles can be suppressed with a smaller amount of the dispersion stabilizer, and the polymer fine particles can be more stably produced.
As the neutralizing agent for the carboxyl group, ammonia and / or a low boiling point amine compound is preferably used because it can be easily removed after the production of the polymer fine particles.

  The macromonomer (Ma) is preferably a chain polymer having a chain molecular structure from the viewpoints of high dispersion stabilization effect, easy production, easy handling, and the like. When the macromonomer (Ma) is a chain polymer, the chain structure may be any of linear, branched, star-shaped, comb-shaped, etc., and of these, linear It is preferable that it is linear or substantially linear from the viewpoints of dispersion stabilization performance of the macromonomer (Ma), ease of production, ease of handling, and the like.

  As the macromonomer (Ma), a compound having an epoxy group and an ethylenically unsaturated group in part of the carboxyl group of the polymer (A) having a carboxyl group in the middle of the molecular chain (hereinafter referred to as “compound (α)”. And a macromonomer obtained by addition reaction (hereinafter referred to as “macromonomer (Ma1)”). This macromonomer (Ma1) has a high degree of freedom in structural design and is excellent in dispersion stability performance in the first polymerization step.

  Further, the number average molecular weight (Mn) of the macromonomer (Ma) is preferably 500 to 20,000, more preferably 1,000 to 2,000 from the viewpoints of dispersion stabilization performance, handleability, ease of production, and the like. 10,000.

The method for producing the macromonomer (Ma) is not particularly limited. For example, when the macromonomer (Ma) is a macromonomer (Ma1), a polymer (A) having a carboxyl group in the middle of a molecular chain as a precursor, and a compound having an epoxy group and an ethylenically unsaturated group ( α) may be reacted.
In the polymer (A), the carboxyl group may be directly bonded in the middle of the molecular chain of the polymer (A), or via a predetermined bonding group in the middle of the molecular chain of the polymer (A). The coupling may be performed in a suspended state, or the above two coupling forms may be mixed.
The polymer (A) is preferably a polymer having a carboxyl group in the middle of the molecular chain and having a chain molecular structure.
In the polymer (A), the number of carboxyl groups bonded in the middle of the molecular chain is preferably more than 2 on average per molecular chain of the polymer (A). More preferably, it is 4 or more.

  Although the manufacturing method of the said polymer (A) is not specifically limited, The homopolymerization or copolymerization of the vinyl monomer which has a carboxyl group, and the vinyl monomer which has a carboxyl group, and other vinyl monomers Copolymerization is preferable in that the degree of freedom in designing the molecular weight, composition, etc. of the polymer is large and a higher performance macromonomer (Ma1) can be obtained as a dispersion stabilizer.

  Examples of the vinyl monomer having a carboxyl group used for the production of the polymer (A) include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid and maleic acid; acrylic acid, methacrylic acid and the like. Dimer or higher oligomer which is a Michael addition reaction product of unsaturated carboxylic acid; ω-carboxypolycaprolactone mono (meth) acrylate, phthalate monohydroxyethyl (meth) acrylate, succinate monohydroxyethyl (meth) acrylate, etc. And carboxyl group-containing (meth) acrylates. These compounds may be used alone or in combination of two or more.

As the other vinyl monomer that can be copolymerized with a vinyl monomer having a carboxyl group in order to produce the polymer (A), a vinyl monomer having no carboxyl group can be used. This monomer may be a hydrophilic monomer or a hydrophobic monomer. Of these, hydrophobic vinyl monomers are preferred. Dispersion stabilization by the macromonomer (Ma1) obtained when the compound (α) is subjected to addition reaction with a part of the carboxyl group in the polymer (A) having a structural unit derived from a hydrophobic vinyl monomer. The performance can be further improved.
Specific examples of hydrophobic vinyl monomers that can be copolymerized with a vinyl monomer having a carboxyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, ( (Meth) acrylic acid isopropyl, (meth) acrylic acid n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid tert-butyl, (meth) acrylic acid n-hexyl, (meth) acrylic acid n-octyl, ( 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, decyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, (meth) acrylic acid (Meth) acrylic esters such as benzyl and perfluoroalkyl (meth) acrylate; acrylonitrile unsaturated nitrile monomers such as α-methylacrylonitrile; styrene monomers such as styrene and α-methylstyrene; vinyl esters of carboxylic acids such as vinyl acetate; unsaturated halogen compounds such as vinyl chloride and vinylidene chloride; ethylene And olefins such as propylene and isobutylene. These compounds may be used alone or in combination of two or more.

The polymer (A) is preferably a copolymer of a vinyl monomer having a carboxyl group and a hydrophobic vinyl monomer. In particular, the copolymerization ratio of the vinyl monomer having a carboxyl group and the hydrophobic vinyl monomer is, by mass ratio, preferably 95: 5 to 10:90, more preferably 80:20 to 20:80. A copolymer having a carboxyl group is preferred. When this copolymer is used, a macromonomer (Ma1) excellent in dispersion stabilization performance can be obtained smoothly. As a specific copolymer, acrylic acid and / or methacrylic acid is used as a vinyl monomer having a carboxyl group, and one or more selected from (meth) acrylic acid ester and styrene as other monomers. And a copolymer using the hydrophobic vinyl monomer. This copolymer is preferable from the viewpoints of dispersion stabilization performance, physical properties of the resulting polymer fine particles, and the like.
(Meth) acrylic acid esters such as methyl (meth) acrylate, isobutyl (meth) acrylate, (meth) acrylic aliphatic lower alcohol esters, (meth) acrylic acid cyclohexyl (meth) acrylic Acid alicyclic alcohol esters and the like are preferred. In particular, an aliphatic lower alcohol ester of (meth) acrylic acid is preferably used from the viewpoint of producing a macromonomer (Ma1) having an excellent dispersion stabilizing effect.

  The carboxyl group equivalent (number of moles of carboxyl groups per gram of polymer (A)) contained in the polymer (A) is preferably 1.5 to 10 meq / g, more preferably 2 to 6 meq / g. .

The number average molecular weight (Mn) of the polymer (A) is preferably 500 to 20,000, more preferably 1,000 to 10,000. By using the polymer (A) having the number average molecular weight (Mn), it is possible to form a macromonomer (Ma1) that is excellent in dispersion stabilization performance, handleability, physical properties of the resulting polymer fine particles, and the like.
In the production of the polymer (A), a molecular weight modifier may be used, and examples of the molecular weight modifier include mercapto compounds such as octyl thioglycolate, butyl mercaptan, dodecyl mercaptan and the like.

As a polymerization method for obtaining the polymer (A), an emulsion polymerization method is preferred. The emulsion polymerization method has a high polymerization rate and can narrow the composition distribution in the polymer. Since the polymer (A) is obtained as submicron-sized fine particles, the addition reaction of the compound (α) to the polymer (A) can be completed in a very short time.
In the emulsion polymerization for obtaining the polymer (A), a vinyl monomer having a carboxyl group is used alone, or a vinyl monomer having a carboxyl group and another vinyl monomer are used in water or in water. It can be carried out in the medium by employing the same method, polymerization conditions and the like as conventional general purpose emulsion polymerization. The use of the hydrophobic vinyl monomer as another vinyl monomer is preferable from the viewpoint that emulsion polymerization can be carried out stably. In the emulsion polymerization, polymerization initiators (polymerization catalysts) such as organic peroxides, azo compounds, and persulfuric compounds, which will be described later, are used in the first polymerization step (dispersion polymerization) for producing polymer fine particles. ) Can be used. Moreover, you may use an emulsifier as needed. It is more preferable to use a persulfuric acid compound such as ammonium persulfate or potassium persulfate as an initiator from the viewpoint that emulsion polymerization can be performed stably without using an emulsifier due to the stabilizing effect of the polymerization initiator section.

The compound (α) is a compound having an epoxy group and an ethylenically unsaturated group.
Examples of the group containing an ethylenically unsaturated group that the compound (α) has include a (meth) acryloyl group, an allyl group, an isopropenyl group, and a styryl group. Among these, it is preferable that the compound (α) contains a (meth) acryloyl group from the viewpoint of obtaining a macromonomer (Ma1) having a high reactivity and dispersion stabilizing effect.
Preferable specific examples of the compound (α) include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether and the like. These compounds may be used alone or in combination of two or more.

  When the polymer (A) is reacted with a compound (α) having an epoxy group and an ethylenically unsaturated group, the compound (α) is added to a part of the carboxyl group existing in the molecular chain of the polymer (A). The epoxy group in the inside is added to obtain a macromonomer (Ma1) in which an ethylenically unsaturated group is introduced in the middle of the molecular chain of the polymer (A). That is, a macromonomer (Ma1) having an ethylenically unsaturated group together with a carboxyl group in the middle of the molecular chain is generated. In the reaction system, the macromonomer (Ma1) and the unreacted polymer (A) may exist and usually coexist. In the present invention, a mixture comprising these polymers can be used as a dispersion stabilizer.

  When the polymer (A) is produced by emulsion polymerization, the addition reaction of the compound (α) to the polymer (A) can be performed using a fine particle dispersion of the polymer (A). After the production of the polymer (A), it is preferable to add the compound (α) to the dispersion of the polymer (A) while maintaining the dispersion state (suspension state). Thereby, since the addition reaction proceeds in the particles of the polymer (A), the reaction rate is extremely high, and the side reaction between the compound (α) and water is suppressed. Further, the solvent to be used is water, which is preferable from the viewpoint of cost and environment, and from the point of not bringing in another organic solvent in the dispersion polymerization stage.

In the addition reaction of the compound (α) to the polymer (A), the amount of the addition reaction of the compound (α) is preferably 0.2 to 1.6 mol (that is, 1 mol of the polymer (A) (that is, 0.2 to 1.6 equivalents), more preferably 0.6 to 1.2 mol (0.6 to 1.2 equivalents). The number of moles of the polymer (A) can be obtained by dividing (dividing) the mass of the actually used polymer (A) by the number average molecular weight (Mn) of the polymer (A).
That is, the number of moles of the compound (α) added per mole of the polymer (A) is the average introduction rate (f value) of the ethylenically unsaturated group per molecule (per polymer chain) of the macromonomer (Ma1). ). Actually, the amount of addition reaction of the compound (α) per molecule of the polymer (A) has a distribution, and there is an unreacted polymer (A) in which the compound (α) has not undergone addition reaction. And constitutes a composition.

Content of ethylenically unsaturated groups per molecule of polymer in the entire polymer containing macromonomer (Ma1) in the obtained polymer composition (mixture comprising polymer) containing macromonomer (Ma1) The average of is 0.2 to 1.74, preferably 0.2 to 1.6, and more preferably 0.6 to 1.2.
In addition, when preparing the said dispersion stabilizer using this polymer composition or a macromonomer (Ma), you may mix | blend another polymer as mentioned above. In this case, the average content of ethylenically unsaturated groups per polymer molecule calculated for the entire polymer contained in the dispersion stabilizer is 0.2 to 1.74, preferably 0.2 to 1.6, more preferably 0.6 to 1.2. When the content of the ethylenically unsaturated group is in the above range, the effect of the dispersion stabilizer is sufficiently exhibited.
If the content of the ethylenically unsaturated group is too small, the dispersion stabilization performance is lowered, and the physical properties of the resulting polymer fine particles are likely to be lowered.
On the other hand, if the content of the ethylenically unsaturated group is too large, the particle size distribution of the polymer fine particles obtained by dispersion polymerization of the vinyl monomer becomes wide, and the sizes tend to be uneven.

Moreover, in the polymer composition containing the macromonomer (Ma1) obtained by reacting the compound (α) with the polymer (A), the carboxyl group content of the whole polymer containing the macromonomer (Ma1) The average value D (unit: meq / g) of the amount is obtained from the following formula (1) based on the addition rate of the compound (α) to the polymer (A).
D = (X−Z) / (100 + Y) (1)
Where
X = carboxyl group amount of polymer (A) (meq / g) × 100
= Amount of carboxyl groups per 100 parts by mass of polymer (A) (meq)
Y = {preparation amount of compound (α) per 100 parts by mass of polymer (A)} × {reaction rate of compound (α) to polymer (A)}
Z = {Y / molecular weight of compound (α)} × 1000
= Amount (meq) of compound (α) added to 100 parts by mass of polymer (A)
It is.

  In addition, when preparing a dispersion stabilizer using the polymer composition containing the said macromonomer (Ma1), you may mix | blend another polymer as mentioned above. In this case, the average value of the carboxyl group content calculated for the whole polymer contained in the dispersion stabilizer is preferably 1 to 9 meq / g, more preferably 1.5 to 5 meq / g. If the content of the carboxyl group is in the above range, the effect of the dispersion stabilizer is sufficiently exhibited.

In the addition reaction of the compound (α) to the polymer (A), a tertiary amine compound, a quaternary ammonium salt compound, a phosphine compound, or the like can be used as a catalyst in order to increase the addition reaction rate. In particular, a tertiary amine compound such as triethylamine is preferably used because it also serves as a neutralizing agent for the carboxyl group of the polymer (A). In particular, when the addition reaction is carried out in an aqueous medium, it is more preferable to use a catalyst because the side reaction in which the compound (α) undergoes an addition reaction with water is reduced.
The carboxyl group remaining in the macromonomer (Ma1) obtained by addition reaction of the compound (α) with a part of the carboxyl group of the polymer (A) is neutralized with a base as described above. The performance as a dispersion stabilizer can be further improved.
Although the reaction conditions are not limited, the addition reaction of the compound (α) to the polymer (A) is usually performed by adding the compound (α) to the solution or dispersion of the polymer (A). , By heating to 50 ° C to 120 ° C.

  The polymer composition containing the macromonomer (Ma1) obtained by the addition reaction to the compound (α) to the polymer (A) has extremely excellent dispersion stabilization performance. That is, in the presence of the dispersion stabilizer containing the macromonomer (Ma), the vinyl monomer is dispersed and polymerized in a polymerization solvent containing a hydrophilic solvent, so that it is in the middle of the molecular chain of the macromonomer (Ma). An ethylenically unsaturated group can be copolymerized with a vinyl monomer to give extremely high dispersion stability to polymer fine particles produced by polymerization of the vinyl monomer. Such high dispersion stability means that the ethylenically unsaturated group is located in the middle of the molecular chain of the macromonomer (Ma), and that the macromonomer (Ma) also has a carboxyl group in the middle of the molecular chain. Is achieved by

Next, a vinyl monomer for producing polymer fine particles in the first polymerization step will be described.
As the vinyl monomer, a vinyl monomer that dissolves in a hydrophilic solvent before polymerization but does not dissolve in a hydrophilic solvent after polymerization can be used.
The vinyl monomer used for the dispersion polymerization is appropriately selected depending on the type and composition of the hydrophilic solvent. For example, (meth) acrylic acid ester; A vinyl monomer having a hydrolyzable silyl group; These monomers may be used alone or in combination of two or more. Moreover, these monomers are preferable from the point which the performance of the polymer fine particle obtained is excellent.

  Specific examples of the (meth) acrylic acid ester preferably used as the vinyl monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. Isopropyl, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, n-hexyl (meth) acrylate, n- (meth) acrylate Alkyl esters of (meth) acrylic acid such as octyl, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate; cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, etc. (Meth) acrylic acid alicyclic group-containing ester; (meth) acrylic acid glycidyl, (meta (Meth) acrylic acid-containing heterocyclic group-containing esters such as tetrahydrofurfuryl acrylate; (meth) acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; ) Alkoxyalkyl esters of (meth) acrylic acid such as 2-methoxyethyl acrylate; ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tetra (meth) ) Polyhydric alcohol esters of (meth) acrylic acid such as pentaerythritol acrylate; allyl (meth) acrylate and the like. These compounds may be used alone or in combination of two or more.

The vinyl monomer having a hydrolyzable silyl group is not particularly limited as long as it is a vinyl monomer having at least one hydrolyzable silyl group. For example, vinyl silanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinyldimethylmethoxysilane; silyl such as trimethoxysilylpropyl acrylate, triethoxysilylpropyl acrylate, and methyldimethoxysilylpropyl acrylate Group-containing acrylic acid esters; silyl group-containing methacrylates such as trimethoxysilylpropyl methacrylate, triethoxysilylpropyl methacrylate, methyldimethoxysilylpropyl methacrylate, dimethylmethoxysilylpropyl methacrylate; trimethoxysilylpropyl vinyl ether, etc. Silyl group-containing vinyl ethers; and silyl group-containing vinyl esters such as vinyl trimethoxysilylundecanoate. These compounds may be used alone or in combination of two or more.
Among them, as the vinyl monomer having a hydrolyzable silyl group, a hydrolyzable silyl group-containing acrylic acid ester and a hydrolyzable silyl group-containing methacrylate ester are preferable. Methoxysilylpropyl methacrylate) and the like are preferable.

  In order to obtain a polymer fine particle having a narrow particle size distribution, a uniform size, excellent physical properties, handleability, etc. by smoothly performing dispersion polymerization while preventing aggregation between the produced polymer fine particles, It is preferable that a monomer contains (meth) acrylic acid ester. The amount of the (meth) acrylic acid ester used is preferably 60% by mass or more, more preferably 65% by mass or more, and still more preferably 70% by mass, based on the total mass of the vinyl monomer used for the production of polymer fine particles. % Or more. As the (meth) acrylic acid ester at that time, an alkyl ester having 1 to 12 carbon atoms or a cycloalkyl ester having 3 to 12 carbon atoms of (meth) acrylic acid is preferable. In particular, an alkyl ester having 1 to 4 carbon atoms of (meth) acrylic acid is preferably used because the performance of the resulting polymer fine particles is excellent.

In the production of polymer fine particles, if a polyfunctional vinyl monomer having two or more ethylenically unsaturated groups (vinyl groups) and / or a vinyl monomer having a hydrolyzable silyl group is used, Polymer fine particles having excellent solvent properties can be produced.
When the vinyl monomer contains a polyfunctional vinyl monomer, fine particles made of a crosslinked polymer can be produced in the first polymerization step.
In addition, when the vinyl monomer includes a vinyl monomer having a hydrolyzable silyl group, the first polymerization step may include fine particles made of a crosslinked polymer by siloxane crosslinking. Fine particles made of the polymer (polymer having a hydrolyzable silyl group) are produced. After the first polymerization step, by performing a hydrolysis step as described later, fine particles made of a crosslinked polymer can be obtained.
When the obtained fine particles are made of a crosslinked polymer, there is little or no dissolution or morphological change in an organic solvent such as methyl ethyl ketone. Therefore, fine particles comprising a crosslinked polymer can be suitably used in applications where solvent resistance and heat resistance are required.

When a polyfunctional vinyl monomer having two or more ethylenically unsaturated groups is used in the first polymerization step, the crosslinking reaction also proceeds with the progress of polymerization. Therefore, if the ratio of the polyfunctional vinyl monomer is large, the polymer fine particles are likely to aggregate. In the case of producing polymer fine particles crosslinked with a polyfunctional vinyl monomer, the ratio of the polyfunctional vinyl monomer used is 0.5 It is preferable to set it as -10 mass%.
Examples of the polyfunctional vinyl monomer include ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth) acrylate. Examples thereof include polyhydric alcohol esters of (meth) acrylic acid and allyl (meth) acrylate. These compounds may be used alone or in combination of two or more.
Among these, allyl (meth) acrylate is preferred because it is easy to suppress aggregation between the polymer fine particles during dispersion polymerization.

In the first polymerization step, when a vinyl monomer having a hydrolyzable silyl group is used, the cross-linking reaction during the polymerization can be suppressed by maintaining the pH of the reaction solution at around neutral during the dispersion polymerization. Then, after polymerization, an acid catalyst or a basic catalyst is added to cause a hydrolysis-condensation-siloxane formation reaction of hydrolyzable silyl groups present in the uncrosslinked polymer fine particles, thereby forming a crosslinked polymer. Combined fine particles can be obtained. The catalyst is preferably a low-boiling basic compound such as ammonia or triethylamine. When these compounds are used, they can be easily removed after the hydrolysis condensation reaction.
When producing polymer fine particles crosslinked using a vinyl monomer having a hydrolyzable silyl group, the proportion of the vinyl monomer having a hydrolyzable silyl group is based on the total amount of the vinyl monomer. Preferably it is 0.5-50 mass%, More preferably, it is 1-30 mass%.
As the vinyl monomer having a hydrolyzable silyl group, the compounds listed above may be used alone or in combination of two or more.

In the first polymerization step, the vinyl monomer is subjected to dispersion polymerization in a hydrophilic solvent in the presence of a dispersion stabilizer containing a macromonomer (Ma).
As polymerization methods, batch polymerization method in which vinyl monomers are charged into a reactor all at once and dispersed and polymerized, split polymerization method in which vinyl monomers are divided and charged into a reactor to be dispersed and polymerized, Examples thereof include a continuous addition polymerization method (semi-batch polymerization method) in which the polymer is continuously added to the reactor and subjected to dispersion polymerization. When it is necessary to control the heat of polymerization, it is preferable to employ a continuous addition polymerization method.

  The amount of the dispersion stabilizer (solid content) containing the macromonomer (Ma) when producing polymer fine particles by dispersion polymerization of the vinyl monomer is based on the total amount of the vinyl monomer used for the dispersion polymerization. Preferably, it is 0.2-10 mass%, More preferably, it is 0.5-5.0 mass%. If the amount of the dispersion stabilizer containing the macromonomer (Ma) is too small, the stability at the time of polymerization is lowered, and the produced polymer tends to aggregate. On the other hand, when the amount of the dispersion stabilizer used is too large, the particle size distribution of the polymer fine particles to be produced becomes wide and the sizes are likely to be uneven.

  The amount of the hydrophilic solvent used in the dispersion polymerization of the vinyl monomer is preferably 1 to 50 times by mass, more preferably 2 to 10 times by mass with respect to the total amount of the vinyl monomer. If the amount of the hydrophilic solvent used is too small, the polymerization stability at the time of dispersion polymerization may be poor, and the particle size distribution tends to be wide. On the other hand, when the amount of the hydrophilic solvent used is too large, the yield of the polymer fine particles is lowered, and the productivity tends to deteriorate.

As the polymerization initiator for the dispersion polymerization of the vinyl monomer, a polymerization initiator usually used in radical polymerization can be used and is not particularly limited. Among them, a radical polymerization initiator that is soluble in a hydrophilic solvent is preferably used. Examples of the radical polymerization initiator that can be used in the present invention include t-butyl peroxypivalate, t-butyl peroxy-2-ethylhexanoate, di-t-butyl peroxide, benzoyl peroxide, and lauroyl peroxide. , Organic peroxides such as orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide; azobisisobutyronitrile, azobiscyclohexacarbonitrile, azobis (2,4- Azo compounds such as dimethylvaleronitrile), 2,2′-azobis (2-amidinopropane) dihydrochloride (V-50), 4,4′-azobis (4-cyanovaleric acid) (V-501); Examples thereof include persulfuric compounds such as potassium persulfate. The said polymerization initiator may use only 1 type and may use it in combination of 2 or more type.
Among these, as the polymerization initiator, t-butyl peroxypivalate and azobis (2,4-dimethylvaleronitrile) are preferably used from the viewpoint that polymer fine particles having a narrow particle size distribution can be produced with high productivity.

  The amount of the polymerization initiator used is not particularly limited, and can be appropriately determined in consideration of the molecular weight of the polymer fine particles to be produced, the decomposition temperature of the polymerization initiator to be used, and the like. In general, the polymerization initiator is preferably used in an amount of 0.1 to 40 parts by weight, and preferably in an amount of 1 to 10 parts by weight with respect to 100 parts by weight of the total amount of vinyl monomers. More preferred. If the amount of the polymerization initiator used is too small, the yield of the polymer fine particles tends to be low. On the other hand, if the amount of the polymerization initiator used is too large, the polymerization rate becomes too high and it is difficult to perform dispersion polymerization stably. Become.

  In the first polymerization step, the polymerization temperature during dispersion polymerization is preferably 40 ° C to 80 ° C, more preferably 45 ° C to 70 ° C. If the polymerization temperature is too low, the polymerization rate of the vinyl monomer will be low and it will be difficult to produce polymer fine particles with good productivity. On the other hand, if the polymerization temperature is too high, aggregation between the produced polymer fine particles will easily occur. In addition, the particle size distribution of the polymer fine particles becomes wide.

  In the present invention, in order to further improve the dispersion stability of the produced polymer fine particles and narrow the particle size distribution, to impart magnetism and conductivity to the polymer fine particles, or to color the polymer fine particles, These additives may be used in combination with a dispersion stabilizer comprising a macromonomer (Ma). Other additives include, for example, metals such as cobalt, iron and aluminum, and alloys thereof, fine powders made of metal oxides such as iron oxide, copper oxide and nickel oxide; pigments such as carbon black nigrosine dye and aniline blue Anionic surfactants such as higher alcohol sulfates, alkylbenzene sulfonates, α-olefin sulfonates and phosphates; Nonionic surfactants such as fatty acid amide derivatives and polyhydric alcohol derivatives; High polar polymer compounds such as propyl cellulose, polyacrylic acid, polyvinyl pyrrolidone, polyethylene glycol, and polyvinyl alcohol can be used. These may be used alone or in combination of two or more.

The polymer fine particles produced by the dispersion polymerization may be used in the form of a dispersion of polymer fine particles while being dispersed in a hydrophilic solvent, or may be used after being separated and recovered from the hydrophilic solvent.
As a method for separating and recovering the polymer fine particles from the hydrophilic solvent, for example, a sedimentation separation method, a centrifugal separation method, a decantation method or the like can be employed, and further, washing and drying are performed as necessary.
In the first polymerization step of the present invention, the produced polymer is precipitated and aggregated one after another without being dissolved in the hydrophilic solvent at the start of polymerization. At that time, the graft polymer of the macromonomer (Ma) and the vinyl monomer is simultaneously and efficiently produced a graft polymer having a very high dispersion stabilizing effect, so that more stable particles are formed at the very initial stage of the polymerization. Furthermore, at the stage where the polymerization of the vinyl monomer proceeds, the graft polymer (copolymerization of the macromonomer (Ma) and the vinyl monomer) is performed in accordance with the speed at which the initially formed stable particles grow as the polymerization proceeds. Produced mainly by the surface of the growing particle. Therefore, aggregation between particles and generation of new particles are highly suppressed. In addition, it is possible to produce polymer fine particles having a very excellent monodispersibility and a narrow particle size distribution with high reproducibility, stably and simply. Further, in the present invention, due to the effect of the macromonomer (Ma), it is possible to form smaller (more) initial stabilizing particles than when a conventional dispersion stabilizer is used. Since the growth can proceed stably, it is possible to produce polymer fine particles that are smaller and excellent in monodispersity.

The polymer fine particles obtained by the first polymerization step may be used as they are without being subjected to a crosslinking treatment or the like, or may be used after being further subjected to a crosslinking treatment or the like, if necessary. A treatment such as introducing a functional group may be performed.
In particular, when the polymer fine particles are non-crosslinked polymer fine particles, the polymer fine particles can be used as seed particles for further reaction. For example, the seed particles can be polymerized after absorbing a vinyl monomer containing a polyfunctional vinyl monomer (second polymerization step). By this second polymerization step, crosslinked polymer fine particles having improved heat resistance, chemical resistance, strength, solvent resistance and the like can be obtained.

As the polyfunctional vinyl monomer, a polyfunctional (meth) acrylate compound, a polyfunctional allyl compound, a polyfunctional propenyl compound, divinylbenzene and the like excellent in polymerizability are preferably used. These compounds may be used alone or in combination of two or more.
Polyfunctional (meth) acrylate compounds include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di ( Di (meth) acrylates of dihydric alcohols such as meth) acrylate; trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide modified tri (meth) acrylate, glycerin tri (meth) acrylate, pentaerythritol tri ( Poly (meth) acrylates such as tri (meth) acrylates and tetra (meth) acrylates of trihydric or higher polyhydric alcohols such as (meth) acrylates and pentaerythritol tetra (meth) acrylates Mention may be made of the rate. These compounds may be used alone or in combination of two or more. Among these, ethylene glycol di (meth) acrylate and trimethylolpropane tri (meth) acrylate can be easily absorbed into the seed particles, and can further increase the crosslink density, and polymerization stability. It is preferably used from the standpoint of superiority.

  The vinyl monomer to be absorbed and polymerized by the seed particles composed of the polymer fine particles obtained by the first polymerization step is a vinyl monomer mixture containing a monofunctional vinyl monomer together with the polyfunctional vinyl monomer described above. It is preferable from the point that absorption of the vinyl monomer to the seed particles and polymerization stability are improved. As the monofunctional vinyl monomer at that time, it is possible to use a vinyl monomer which is the same as or similar to the vinyl monomer used for the production of seed particles (polymer fine particles obtained by dispersion polymerization). This is preferable in that the polymer particles are swelled satisfactorily and thereby the absorption of the vinyl monomer mixture into the seed particles is promoted to obtain crosslinked polymer fine particles which are sufficiently crosslinked.

  In the second polymerization step, when the polymer fine particles obtained in the first polymerization step are used as seed particles to produce crosslinked polymer fine particles, the vinyl monomer containing the seed particles and the crosslinkable monomer is used. The proportion of the body (vinyl monomer mixture) used is preferably 0.5 to 10 parts by mass of vinyl monomer (vinyl monomer mixture) with respect to 1 part by mass of seed particles. More preferably, it is -5 mass parts. In that case, based on the total mass of a vinyl monomer mixture, it is preferable to make the ratio of a polyfunctional vinyl monomer into 3-95 mass%, especially 5-75 mass%.

The polymer fine particles obtained by the dispersion polymerization of the present invention described above generally have a volume average particle diameter (dv) of 0.7 to 0.7 in both cases of non-crosslinked polymer fine particles and crosslinked polymer fine particles. It is 2.0 μm, has a very fine particle shape, has a particle size variation coefficient (Cv) of 20% or less, has a narrow particle size distribution, and has a uniform size.
In the polymer fine particles obtained in the present invention, the volume average particle diameter (dv) is preferably 0.8 to 1.4 μm, and the particle size variation coefficient (Cv) is preferably 10% or less. The polymer fine particles can be produced smoothly by the method of the present invention.
Here, the volume average particle diameter (dv) of the polymer fine particles in the present specification is calculated based on a particle image obtained by taking a photograph of the polymer fine particles using a scanning electron microscope (dv). The detailed calculation method is as described in the following examples.
Further, the coefficient of variation (Cv) of the particle size of the polymer fine particles in this specification refers to the coefficient of variation (Cv) of the particle size obtained by the method described in the following examples.

  The polymer fine particles obtained by the dispersion polymerization method of the present invention have a very small particle size of micron size, and have a uniform size with a narrow particle size distribution, are monodisperse and have no aggregation between particles, Crosslinked polymer fine particles are also excellent in heat resistance, chemical resistance, strength and the like. Therefore, taking advantage of these properties, various applications including liquid crystal display spacers, light diffusing films for liquid crystal displays, light diffusion agents such as diffusion plates, conductive fine particles, column fillers, diagnostic reagents carriers, etc. Can be suitably used.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention concretely, this invention is not limited to the following examples at all.

1. Evaluation method of physical properties In the following examples, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer, the addition rate of the compound (α) to the polymer (A), the polymerization stability, the volume of the polymer fine particles The average particle diameter (dv), number average particle diameter (dn), coefficient of variation in particle size (Cv), amount of by-product small particles, and the method for measuring or evaluating the solvent resistance of crosslinked polymer fine particles are as follows: It is as follows.

1-1. Weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer
The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer (A) and the like were calculated in terms of polystyrene by gel permeation chromatography (GPC).
Specifically, “HLC-8120GPC” (model name) manufactured by Tosoh Corporation was used as the GPC apparatus. As the column, four “TSKgel super MP-M” (trade name) were used, tetrahydrofuran was used as a developing solvent, and measurement was performed under conditions of a flow rate of 0.35 ml / min and a column temperature of 40 ° C. The measurement results were analyzed using a calibration curve prepared with standard polystyrene, and the weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene were determined.
When the polymer (A) is measured, the volatile matter is removed from the dispersion and the polymer (A) is isolated. Then, the polymer (A) is dissolved in tetrahydrofuran, and the resulting solution (concentration 5 mg / ml).
When measuring a polymer composition containing a macromonomer (Ma) (a mixture composed of a polymer), it is as follows. The dispersion was acidified with an appropriate amount of hydrochloric acid, and then volatile components were removed. Next, the nonvolatile content was recovered and washed with water. Then, water was removed, the entire polymer containing the macromonomer (Ma) was dissolved in tetrahydrofuran, and the resulting solution (concentration 5 mg / ml) was used.

1-2. Addition rate of compound (α) to polymer (A) The residual amount of compound (α) and the amount of by-products produced were measured by gas chromatography (GC), and the compound (α) to polymer (A) was measured. ) Addition rate. In the following Production Examples 1 to 13, glycidyl methacrylate was used as the compound (α).
Specifically, using “GC-263-30” manufactured by Hitachi as a GC device, using an FID detector and Zebron ZB-5 (30 m) as a column, the reaction solution was diluted with distilled water. Samples added with methyl cellosolve acetate as an internal standard substance, nitrogen gas as a carrier gas, a flow rate of 10 ml / min, and a column temperature increased from 50 ° C. to 200 ° C. at 7.5 ° C./min. And measured. From the peak areas of the internal standard substance (methyl cellosolve acetate), glycidyl methacrylate, and the water adduct of glycidyl methacrylate, the amount of glycidyl methacrylate remaining unreacted and the amount of water adduct of glycidyl methacrylate were quantified. The water addition rate of glycidyl methacrylate was determined by dividing the amount of glycidyl methacrylate consumed by water addition by the total amount of glycidyl methacrylate. The addition rate of glycidyl methacrylate to the polymer (A) is obtained by subtracting the amount of residual glycidyl methacrylate and the amount of glycidyl methacrylate consumed by water addition from the total amount of glycidyl methacrylate, and dividing by the total amount of glycidyl methacrylate. It was.

1-3. Evaluation of Polymerization Stability After the dispersion of polymer fine particles obtained by polymerization was taken out from the reactor, the amount of polymer adhered to the inside of the reactor and the stirring blade was visually observed. Further, the dispersion of polymer fine particles taken out from the reactor is filtered through a 200 mesh polynet (aperture: 114 μm), and the amount of aggregate remaining on the polynet is visually observed. From these observation results, polymerization stability was evaluated according to the following evaluation criteria.

[Evaluation criteria for polymerization stability]
○: The polymer does not adhere to the inside of the reactor and the stirring blade, or the adhesion is negligible, and there is no or little residue of aggregates on the polyethylene.
(Triangle | delta): There is little adhesion of the polymer to the inside of a reactor and a stirring blade, and there is little residue of the aggregate on a polynet.
X: The amount of polymer adhered to the inside of the reactor and the stirring blade is large, and a large amount of aggregate remains on the polyethylene.

1-4. Volume average particle diameter (dv), number average particle diameter (dn), coefficient of variation of particle size (Cv) and amount of by-product small particles of polymer fine particles Volatile matter (polymerization solvent, The polymer fine particles recovered by removing the residual monomers and the like were photographed by SEM using a field emission scanning electron microscope (FE-SEM) “JSM-6330F” (model name) manufactured by JEOL Ltd. At that time, the magnification of photography by the SEM method was set to a magnification at which about 200 particles were photographed in one photograph, and three photographs were taken at different photographing positions.
In the above SEM image, the particle diameter (di), which is an area equivalent circle diameter determined from the area of the particle, is measured for all the polymer fine particles of 0.3 μm or more capable of accurate particle diameter measurement, and the following According to the mathematical formulas (I), (II) and (III), the volume average particle size (dv), the number average particle size (dn) and the coefficient of variation (Cv) of the particle size were calculated. ni represents the number of particles having a particle diameter of di.
Volume average particle diameter (dv) = (Σnidi ³ / Σni) ^1/3 (I)
Number average particle diameter (dn) = (Σnidi / Σni) (II)
Coefficient of variation of particle size (Cv) (%) = 100σ / dn (III)
σ (standard deviation) = (Σ (di−dn) ² / Σni) ^1/2 (IV)

  The coefficient of variation (Cv) means that the smaller the value (closer to zero), the narrower the particle size distribution, the uniform particle diameter, and the uniform particle size.

The amount of small particles (by-product small particles) having a particle diameter of less than 0.3 μm was evaluated according to the following criteria from the result of visual observation of the SEM image.
[Evaluation criteria for amount of by-product small particles]
○: By-product small particles are not generated or very little.
Δ: A small amount of by-product small particles are generated.
×: A large amount of by-product small particles are generated.

1-5. Solvent Resistance of Crosslinked Polymer Fine Particles Crosslinked polymer fine particles were dispersed in 20 mass times methyl ethyl ketone, and then allowed to stand at 25 ° C. for 24 hours. Thereafter, whether or not the polymer fine particles were dissolved or swollen in methyl ethyl ketone was visually observed. Next, for polymer fine particles that do not dissolve or coalesce (aggregate) between particles due to swelling and can be redispersed while maintaining the particle shape, methyl ethyl ketone is removed while standing at room temperature, and the above 1 Photographs were taken by the SEM method in the same manner as -4. Then, the SEM image is compared with the SEM image of the polymer fine particles before the test, and the change in particle size, the change in shape, and the presence or absence of the eluted polymer component are examined. evaluated.

[Evaluation criteria for methyl ethyl ketone resistance]
○: When comparing the SEM images of the polymer fine particles before and after the test, there is almost no change in the particle size and particle morphology.
Δ: SEM image of the polymer fine particle after the test confirms that it has a particle shape, but the particle size and / or the particle shape has changed or eluted to the outside of the polymer fine particle. The polymer component is confirmed.
X: Polymer fine particles are dissolved in methyl ethyl ketone, or coalescence between the polymer fine particles due to swelling is remarkable, and cannot be redispersed after standing for 24 hours.
This test was performed on the crosslinked polymer fine particles (PC-1) to (PC-15) obtained in Examples 11 to 25.

2. Production of liquid containing dispersion stabilizer Production Example 1 (Production of Dispersion (DS1))
Into a glass reactor equipped with a stirrer, reflux condenser, thermometer, nitrogen inlet pipe and liquid feed pipe connecting part, 200 parts by mass of ion-exchanged water was charged while stirring and blowing in nitrogen gas. The temperature was adjusted to 80 ° C.
On the other hand, 31.6 parts by mass of methyl methacrylate, 31.6 parts by mass of isobutyl methacrylate, 30.0 parts by mass of methacrylic acid, and 2-ethylhexyl thioglycolate in a glass container equipped with a liquid feeding pipe by a metering pump 8 parts by mass was charged and stirred to prepare a monomer mixture (100 parts by mass).
After confirming that the internal temperature of the reactor was stabilized at 80 ° C., a polymerization initiator aqueous solution in which 0.8 parts by mass of ammonium persulfate (polymerization initiator) was dissolved in 3.0 parts by mass of ion-exchanged water in the reactor. Was added. Then, after 5 minutes, using a metering pump, the supply of the monomer mixture to the reactor was started, and 100 parts by mass of the monomer mixture was added at a constant rate for 120 minutes. Supplied to. The internal temperature of the reactor was maintained at 80 ° C. even after the supply was completed. Thereafter, 90 minutes after the completion of the supply, an oxidizing agent aqueous solution in which 0.1 part by mass of t-butyl hydroperoxide (oxidizing agent) was dissolved in 2.0 parts by mass of ion-exchanged water was added, and further 5 minutes later, hydrosulfite. A reducing agent aqueous solution in which 0.3 parts by mass of sodium (reducing agent) was dissolved in 4.0 parts by mass of ion-exchanged water was added. Furthermore, the internal temperature of the reactor was maintained at 80 ° C. for 25 minutes to obtain a dispersion of a polymer (A) having a carboxyl group in the middle of the molecular chain (hereinafter referred to as polymer (A-1)). A small amount of the dispersion was sampled and dried, and then GPC measurement was performed. As a result, the polymer (A-1) had a weight average molecular weight (Mw) of 7500 and a number average molecular weight (Mn) of 3000. Moreover, the carboxyl group amount of the polymer (A-1) is calculated as 3.49 meq / g from the monomer composition.

Next, while maintaining the temperature of the dispersion of the polymer (A-1) in the reactor at 80 ° C., the nitrogen gas blowing was changed to air blowing, and immediately 14.1 parts by mass of triethylamine and methoxyhydroquinone 0.03 part by mass was added. And 15 minutes later, 4.73 parts by mass of glycidyl methacrylate was added and heated at an internal temperature of 80 ° C. for 3 hours to add glycidyl methacrylate to a part of the carboxyl groups of the polymer (A-1), and methacryloyl. A dispersion of a polymer composition (a mixture made of a polymer) containing a macromonomer having a group was produced. Hereinafter, this polymer composition is referred to as “polymer composition (Ma-1)”.
Then, a part was sampled from the dispersion liquid of the polymer composition (Ma-1) containing the macromonomer obtained above, and GC analysis was performed by said method. As a result of the measurement, glycidyl methacrylate was not detected. Further, a glycidyl methacrylate water adduct corresponding to 6% of glycidyl methacrylate was detected. From this result, it is calculated that the addition rate of glycidyl methacrylate to the polymer (A-1) is 94% and the water addition rate is 6%. Therefore, the polymer composition (Ma-1) is calculated by the calculation described later using the number average molecular weight (Mn) of the polymer (A-1) and the addition rate of glycidyl methacrylate to the polymer (A-1). It was found to have an average of 0.94 ethylenically unsaturated groups per molecule (per polymer chain). That is, it was found that the average introduction rate (f value) of ethylenically unsaturated groups was 94%.
Subsequently, ion-exchange water is added to the dispersion liquid of the polymer composition (Ma-1) obtained above, and a dispersion liquid having a solid content concentration of the polymer composition (Ma-1) of 30 mass% ( Hereinafter, “dispersion liquid (DS1)” was prepared.

  The average introduction rate (f value) of ethylenically unsaturated groups and the average value of the content of carboxyl groups in the polymer composition (Ma-1) obtained above were determined by the following calculation.

[Calculation of average introduction rate (f value) of ethylenically unsaturated groups in polymer composition]
The number of moles of 100 parts of the polymer (A-1) is 100/3000 using Mn (3000) of the polymer (A).
4.73 parts × 0.94 of glycidyl methacrylate is added to 100 parts of the polymer (A-1).
From the molecular weight (142) of glycidyl methacrylate, the number of moles added of glycidyl methacrylate is (4.73 parts × 0.94) / 142. Therefore,
f value = {number of moles of added glycidyl methacrylate} / {number of moles of polymer (A-1)}
= (4.73 × 0.94 / 142) / (100/3000)
= 0.94
Is obtained.

[Calculation of average value (meq / g) of carboxyl group content in polymer composition]
The average value (D) of the carboxyl group content in the polymer composition was determined according to the above mathematical formula (1).
In particular,
X = amount of carboxyl group per 100 parts by mass of polymer (A-1) = 349 (meq)
Y = {charging amount of glycidyl methacrylate with respect to 100 parts by mass of polymer (A-1)} × {addition ratio of glycidyl methacrylate to polymer (A-1)}
= 4.73 x 0.94
= 4.45 parts by mass (the amount of glycidyl methacrylate (parts by mass) added to 100 parts by mass of the polymer (A-1))
Z = {Y / molecular weight of glycidyl methacrylate} × 1000
= (4.45 / 142) x 1000
= 31.3 (meq) (the amount of glycidyl methacrylate (meq) added to 100 parts by mass of the polymer (A-1))
Thus, D = 3.04 meq / g was obtained.

  The average introduction rate (f value) of ethylenically unsaturated groups and the amount of carboxyl groups in the polymer compositions obtained in the following Production Examples 2 to 13 were also determined in the same manner as described above.

Production Examples 2 to 7 (Production of Dispersions (DS2) to (DS7))
Polymers (A-2) to (A-7) having a carboxyl group in the middle of the molecular chain by performing the same operation as in Production Example 1 using monomers having the compositions shown in Table 1 and Table 2 below. ) Dispersion was produced. After sampling and drying a small amount of the dispersion, GPC measurement was performed by the method described above. The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymers (A-2) to (A-7) were: It was as shown in Table 1 and Table 2. Moreover, the amount of carboxyl groups of the polymers (A-2) to (A-7) was as shown in Table 1 and Table 2 below from the monomer composition.
To the dispersions of the polymers (A-2) to (A-7) obtained above, the amounts of triethylamine and glycidyl methacrylate shown in Table 1 and Table 2 below were added, and in the same manner as in Production Example 1, Glycidyl methacrylate is added to a part of the carboxyl groups of the polymers (A-2) to (A-7) to form a polymer composition containing a macromonomer (polymer composition (Ma-2) to (Ma-7)). )) Dispersion.
Then, a part was sampled from the dispersion liquid containing polymer composition (Ma-2)-(Ma-7) obtained above, and GC analysis was performed by said method. As a result of the measurement, glycidyl methacrylate was not detected in all the dispersions. Further, the amount of glycidyl methacrylate water adduct was measured, and in the same manner as in Production Example 1, ethylene per molecule (per polymer chain) of polymer compositions (Ma-2) to (Ma-7). When the average number of the ethylenically unsaturated groups [average introduction rate of ethylenically unsaturated groups (f value)] was determined, it was as shown in Tables 1 and 2.
To the dispersions of the polymer compositions (Ma-2) to (Ma-7) obtained above, ion-exchanged water was added, and the dispersion (DS2 with a solid content concentration of the polymer composition of 30% by mass was added. ) To (DS7) were prepared.

Production Examples 8 to 13 (Production of Dispersions (DS8) to (DS13))
Polymers (A-8) to (A-13) having a carboxyl group in the middle of the molecular chain are obtained by performing the same operation as in Production Example 1 using monomers having the compositions shown in Table 3 and Table 4 below. ) Dispersion was produced. After sampling and drying a small amount of the dispersion, GPC measurement was performed by the method described above. The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymers (A-8) to (A-13) were As shown in Table 3 and Table 4 below. Moreover, the amount of carboxyl groups of the polymers (A-8) to (A-13) was as shown in Table 3 and Table 4 from the monomer composition.
To the dispersions of the polymers (A-8) to (A-13) obtained above, the amounts of triethylamine and glycidyl methacrylate shown in Table 3 and Table 4 below were added, and in the same manner as in Production Example 1, Glycidyl methacrylate is added to a part of the carboxyl groups of the polymers (A-8) to (A-13), and a polymer composition containing a macromonomer (polymer composition (Ma-8) to (Ma-13)). )) Dispersion.
Then, a part was sampled from the dispersion liquid containing the polymer composition (Ma-8)-(Ma-13) obtained above, and GC analysis was performed by said method. As a result of the measurement, glycidyl methacrylate was not detected in all the dispersions. Further, the amount of glycidyl methacrylate water adduct was measured, and in the same manner as in Production Example 1, ethylene per molecule (per polymer chain) of polymer compositions (Ma-8) to (Ma-13). The average number of ethylenically unsaturated groups [average introduction rate of ethylenically unsaturated groups (f value)] was determined and as shown in Tables 3 and 4.
Ion exchange water is added to the dispersions of the polymer compositions (Ma-8) to (Ma-13) obtained above, and the dispersion (DS8 having a solid content concentration of the polymer composition of 30% by mass is added. ) To (DS13) were prepared.

Production Example 14 (Production of dispersion stabilizer aqueous solution (DS14))
A 500 ml pressurized stirred tank reactor equipped with a hot oil heating device was filled with ethyl 3-ethoxypropionate. The reactor was heated to about 250 ° C., and the pressure in the reactor was set to be equal to or higher than the vapor pressure of ethyl 3-ethoxypropionate by a pressure controller.
Thereafter, 20 parts by mass of methyl methacrylate, 55 parts by mass of cyclohexyl acrylate, 25 parts by mass of acrylic acid and 0.1 part of di-t-butyl peroxide were weighed and mixed to prepare a monomer mixture. And this monomer mixed liquid was stored in the raw material tank.
Next, the monomer mixture prepared above was continuously supplied from the raw material tank to the reactor while keeping the pressure in the reactor constant. At this time, the feed rate was set so that the average residence time of the monomer mixture in the reactor was 12 minutes. A reaction solution corresponding to the supply amount of the monomer mixture was continuously withdrawn from the outlet of the reactor. During the continuous supply of the monomer mixture, the internal temperature of the reactor was maintained at 230 ° C. ± 2 ° C. The reaction liquid extracted from the outlet of the reactor is introduced into a thin film evaporator to remove volatile components such as unreacted monomers in the reaction liquid, and the polymer (A-14), that is, the end of the molecular chain A macromonomer (Mb-1) having a vinylidene group was obtained. After 90 minutes from the start of supplying the monomer mixture, the collection of the macromonomer (Mb-1) was started from the outlet of the thin film evaporator, and was collected for 60 minutes.

When the weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured for the macromonomer (Mb-1) obtained above, the weight average molecular weight (Mw) was 10600, and the number average molecular weight (Mn) was 3100. there were.
Moreover, in the macromonomer (Mb-1) obtained above, the terminal ethylenic unsaturation calculated from the concentration of the terminal ethylenically unsaturated bond and the number average molecular weight (Mn) measured by ¹ H-NMR. The introduction rate of the bond (terminal vinylidene group) was 98%.
Next, the macromonomer (Mb-1) obtained above is pulverized into flakes, and 100 parts by mass of the pulverized macromonomer (Mb-1), 260 parts by mass of water and 22.5 parts by mass of 25% aqueous ammonia. Was stirred in a glass flask with a condenser tube while heating in a 90 ° C. warm bath to make the macromonomer (Mb-1) water-soluble. After confirming that the macromonomer (Mb-1) was dissolved, water was added so that the solid content was 25% by mass, and an aqueous solution of the macromonomer (Mb-1) (hereinafter, “dispersion liquid (DS14)”). Manufactured). The pH of this solution (DS14) at 25 ° C. was 8.0.

  The contents of the dispersions (DS1) to (DS13) obtained in Production Examples 1 to 13 and the dispersion (DS14) obtained in Production Example 14 are shown in Tables 1 to 4.

3. Production of polymer fine particles (1)
Example 1 (Production of polymer fine particles (PA-1))
In a glass reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube, 110.9 parts by mass of ion-exchanged water, 464 parts by mass of methanol, and the polymer composition produced in Production Example 1 (dispersion stabilizer) A dispersion liquid (DS1) containing 6.67 parts by mass (equivalent to 2 parts by mass of solid content), 0.41 part by mass of 25% aqueous ammonia, 50 parts by mass of methyl methacrylate and 50 parts by mass of isobutyl methacrylate, and stirring and nitrogen The inner temperature of the reactor was adjusted to 55 ° C. while blowing gas.
After confirming that the internal temperature of the reactor was stabilized at 55 ° C., a 70% solution of t-butyl peroxypivalate (trade name “Perbutyl PV”, Nippon Oil & Fats Co., Ltd.) was used as a polymerization initiator in the reactor. Polymerization was started by adding 2.4 parts by mass). Immediately after the addition of the polymerization initiator, the reaction solution became turbid, gradually whitened to become milky white, and it was confirmed that polymer fine particles (hereinafter referred to as “polymer fine particles (PA-1)”) were produced. .

After the addition of the polymerization initiator, 240 minutes passed, the reaction solution was cooled to complete the polymerization. The polymerization reaction liquid was passed through a 200-mesh polynet to collect a dispersion of polymer fine particles (PA-1). There was no adhesion of the polymer to the inside of the reactor and the stirring blade after the polymerization reaction liquid was extracted, and further, no filtration residue was observed on the 200th polynet. It was judged.
Next, volatile matter was removed at room temperature from the dispersion of polymer fine particles (PA-1) obtained above, and polymer fine particles (PA-1) were recovered. And SEM observation was performed about polymer fine particles (PA-1) with the above-mentioned method. From the obtained SEM image, the volume average particle size (dv) was 1.43 μm, the number average particle size (dn) was 1.43 μm, and the coefficient of variation (Cv) in particle size was 5.4%. Further, from the SEM image, it was confirmed that the amount of by-product small particles of 0.3 μm or less was very small.
The SEM image of the polymer fine particles (PA-1) obtained in Example 1 is shown in FIGS. FIG. 1 was taken at a magnification of 2,000 times, and FIG. 2 was taken at a magnification of 12,000 times.

Examples 2 to 10 (Production of polymer fine particles (PA-2) to (PA-10))
Polymer fine particles (hereinafter referred to as “polymer fine particles (PA)” were used in the same manner as in Example 1 except that the type and amount of the dispersion and the amounts of 25% ammonia water and water used were as shown in Table 5. -2) to (PA-10) "). And when evaluation of polymerization stability was performed in the same manner as in Example 1, it was as shown in Table 5.
In all of the above-described Example 1 and Examples 2-10, the amount of water used was such that the total amount of water and 25% ammonia water in the dispersion was 116 parts by mass.
The volume average particle diameter (dv), number average particle diameter (dn), and coefficient of variation (Cv) of the particle size of the polymer fine particles (PA-2) to (PA-10) obtained above are shown in Example 1. As a result, the results were as shown in Table 5.
Moreover, when the production amount of by-product small particles of 0.3 μm or less was evaluated from the SEM image, it was as shown in Table 5.

Comparative Example 1 (Production of polymer fine particles (PB-1))
As a liquid containing a dispersion stabilizer, instead of the dispersion liquid (DS1), the dispersion liquid (DS14) obtained in Production Example 14 was used in an amount shown in Table 6 below, and further 25% aqueous ammonia and water were used. A dispersion of polymer fine particles (hereinafter referred to as “polymer fine particles (PB-1)”) was produced in the same manner as in Example 1 except that the amount was changed as shown in Table 6. When the polymerization stability was evaluated in the same manner as in Example 1, it was as shown in Table 6.
In Comparative Example 1 as well, the amount of water used was such that the total amount of water and 25% aqueous ammonia contained in the dispersion (DS14) was 116 parts by mass. The macromonomer (Mb-1) (dispersion stabilizer) contained in the dispersion liquid (DS14) used in Comparative Example 1 has already been neutralized with ammonia at the stage of water solubilization. Was not added anew.
When the volume average particle diameter (dv), number average particle diameter (dn), and coefficient of variation (Cv) of the particle size of the polymer fine particles (PB-1) obtained above were determined in the same manner as in Example 1. Table 6 shows the results.
Moreover, when the production amount of by-product small particles of 0.3 μm or less was evaluated from the SEM image, it was as shown in Table 6.

Comparative Example 2 (Production of polymer fine particles (PB-2))
As a dispersion stabilizer, instead of the polymer composition (Ma-1) containing a macromonomer, polyvinylpyrrolidone (trade name “K-30”, manufactured by Wako Pure Chemical Industries, Ltd., Example of JP-A-9-157307) 1) was used in the amounts shown in Table 6 below, and 25% aqueous ammonia and water were used in the same manner as in Example 1 except that the amounts used were changed as shown in Table 6. Hereinafter, a dispersion of “polymer fine particles (PB-2)” was produced. When the polymerization stability was evaluated in the same manner as in Example 1, it was as shown in Table 6.
In Comparative Example 2 as well, the amount of water used was such that the total amount of water and 25% ammonia water in the dispersion was 116 parts by mass.
The volume average particle size (dv), number average particle size (dn), and coefficient of variation (Cv) of the particle size of the polymer fine particles (PB-2) obtained above were determined in the same manner as in Example 1. Table 6 shows the results.
Moreover, when the production amount of by-product small particles of 0.3 μm or less was evaluated from the SEM image, it was as shown in Table 6.

Comparative Example 3 (Production of polymer fine particles (PB-3))
As a dispersion stabilizer, instead of the polymer composition (Ma-1) containing a macromonomer, polyethylene oxide having a methacryloyl group at one end (trade name “M-90G”, manufactured by Shin-Nakamura Chemical Co., Ltd., average ethylene oxide The number of additions is 9, and the other end is a methoxy group (used in Example 3 of JP-A-9-157307) in the amounts shown in Table 6 below, and further 25% ammonia water and water usage Was changed in the manner shown in Table 6 in the same manner as in Example 1 to produce a dispersion of polymer fine particles (hereinafter referred to as “polymer fine particles (PB-3)”). However, since a large amount of agglomerate was generated within 1 hour after the addition of the polymerization initiator and stirring became difficult, the polymerization was stopped and polymer fine particles (PB-3) could not be produced.

Comparative Example 4 (Production of polymer fine particles (PB-4))
Instead of the polymer composition (Ma-1) containing a macromonomer as a dispersion stabilizer, polyvinylpyrrolidone (trade name “K-30”, manufactured by Wako Pure Chemical Industries, Ltd., Example of JP-A-9-157307) 1) was used in the amounts shown in Table 6 below, and 25% aqueous ammonia and water were used in the same manner as in Example 1 except that the amounts used were changed as shown in Table 6. Polymer fine particles A dispersion liquid (hereinafter referred to as “polymer fine particles (PB-4)”) was produced. When the polymerization stability was evaluated in the same manner as in Example 1, it was as shown in Table 6.
In Comparative Example 4, the amount of water used was such that the total amount of water and 25% ammonia water in the dispersion was 116 parts by mass.
The volume average particle size (dv), number average particle size (dn), and variation coefficient (Cv) of the particle size of the polymer fine particles (PB-4) obtained above were determined in the same manner as in Example 1. Table 6 shows the results.
Moreover, when the production amount of by-product small particles of 0.3 μm or less was evaluated from the SEM image, it was as shown in Table 6.

  As can be seen from the results of Tables 5 and 6, Examples 1 to 10 are polymer compositions containing a macromonomer having a carboxyl group and an ethylenically unsaturated group in the middle of a molecular chain as a dispersion stabilizer ( This is an example in which dispersion polymerization of vinyl monomers (methyl methacrylate and isobutyl methacrylate) was performed in a hydrophilic solvent using Ma-1) to (Ma-7). By using a very small amount of dispersion stabilizer, polymer fine particles having a volume average particle size (dv) of 1.71 μm or less and a very small particle size are obtained with a narrow particle size distribution with a coefficient of variation of particle size (Cv) of 20% or less. Thus, it is smoothly obtained with good polymerization stability without causing aggregation or the like between the polymer fine particles.

On the other hand, Comparative Example 1 is an example using the polymer composition (Mb-1) as a dispersion stabilizer. The macromonomer contained in the polymer composition (Mb-1) is a macromonomer having a vinylidene group at the end of the molecular chain, and does not have an ethylenically unsaturated group in the middle of the molecular chain. The volume average particle diameter (dv) of the obtained polymer fine particles (PB-1) is 2.53 μm, and the size of the polymer fine particles is significantly larger than the polymer fine particles obtained in Examples 1 to 10. Met.
Moreover, in Comparative Example 1, it was necessary to use a polymer composition (Mb-1), which is a dispersion stabilizer, in a larger amount than in Examples 1 to 10 in order to perform dispersion polymerization stably.

  In addition, as seen in the results of Comparative Examples 2 and 4, when dispersion polymerization was performed using polyvinyl pyrrolidone used in the prior art such as Patent Document 1 as a dispersion stabilizer, a large amount of polyvinyl pyrrolidone was used. Can be used to produce polymer fine particles having a volume average particle diameter (dv) of 2 μm or less (Comparative Example 2). However, as seen in Comparative Example 4, when the amount of polyvinylpyrrolidone used is as small as 2.00 parts by mass in terms of solid content as in Examples 1 to 10, dispersion polymerization cannot be performed stably. Moreover, the polymer fine particles (PB-4) obtained by dispersion polymerization had a volume average particle diameter (dv) exceeding 3 μm, and it was impossible to produce fine polymer fine particles.

  Furthermore, as seen in the results of Comparative Example 3, when dispersion polymerization was performed using a macromonomer composed of polyethylene oxide having a methacryloyl group at one end used in the prior art such as Patent Document 1 as a dispersion stabilizer In spite of the use of a large amount of the macromonomer, the polymer agglomerates in the initial stage of the polymerization, so that the dispersion polymerization cannot be carried out, and consists of a polyethylene oxide having a methacryloyl group at one end. The macromonomer was greatly inferior in performance as a dispersion stabilizer.

4). Production of polymer fine particles (2)
Example 11 (Production of crosslinked polymer fine particles (PC-1))
In a glass reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introduction tube, 134.3 parts by mass of ion-exchanged water, 440.8 parts by mass of methanol, 0.21 parts by mass of 25% aqueous ammonia (for neutralization) Parts, 6.67 parts by mass of the liquid (DS4) containing the polymer composition (dispersion stabilizer) produced in Production Example 4, 40.0 parts by mass of methyl methacrylate and 50.0 parts by mass of isobutyl methacrylate were stirred and stirred. The internal temperature of the reactor was adjusted to 55 ° C. while blowing nitrogen gas.
After confirming that the internal temperature of the reactor was stabilized at 55 ° C., 10.0 parts by mass of trimethoxysilylpropyl methacrylate was added to the reactor, and 10 minutes later, the same polymerization as that used in Example 1 was performed. Polymerization was initiated by adding 2.4 parts by weight of an initiator (70% solution of t-butyl peroxypivalate). Immediately after the addition of the polymerization initiator, the reaction solution was turbid, gradually whitened to become milky white, and it was confirmed that polymer fine particles were generated. For 4 hours after the addition of the polymerization initiator, the internal temperature of the reactor was maintained at 55 ° C. to obtain a dispersion of polymer fine particles having hydrolyzable silyl groups.

Subsequently, 32.9 parts by mass of 25% aqueous ammonia was added as a basic catalyst for crosslinking the hydrolyzable silyl group. Thereafter, the internal temperature of the reactor was raised to 68 ° C. and held at that temperature for 3 hours to produce crosslinked polymer fine particles (hereinafter referred to as “crosslinked polymer fine particles (PC-1)”).
Next, the reaction liquid containing the crosslinked polymer fine particles (PC-1) obtained above was cooled, and then taken out from the reactor while being filtered through a 200-mesh polynet, to obtain crosslinked polymer fine particles (PC- The dispersion of 1) was recovered. No polymer adhered to the inside of the reactor or the stirring blade after the polymerization reaction liquid was extracted, and no filtration residue was observed on the 200th polynet. It was done.
Thereafter, the dispersion of the crosslinked polymer fine particles (PC-1) collected above was dried at 60 ° C. until the nonvolatile content when heated at 155 ° C. for 30 minutes was 98% by mass or more, and crushed after drying. Thus, crosslinked polymer fine particles (PC-1) were obtained. And in an uplifting way,
SEM observation was performed about cross-linked polymer fine particles (PC-1). From the obtained SEM image, the volume average particle size (dv) was 1.18 μm, the number average particle size (dn) was 1.17 μm, and the coefficient of variation (Cv) in particle size was 6.8%. Further, from the SEM image, it was confirmed that the amount of by-product small particles of 0.3 μm or less was very small.

Next, the above-mentioned crosslinked polymer fine particles (PC-1) were dispersed in 20 mass times methyl ethyl ketone and allowed to stand at 25 ° C. for 24 hours. After 24 hours, the crosslinked polymer fine particles (PC-1) were precipitated in methyl ethyl ketone. However, there was no aggregation or coalescence between the particles, and they could be easily redispersed. The re-dispersed crosslinked polymer fine particles (PC-1) were taken out from methyl ethyl ketone and dried at room temperature. And when it observed using SEM like the above, crosslinked polymer microparticles | fine-particles (PC-1) were not different from the crosslinked polymer microparticles | fine-particles (PC-1) before being immersed in methyl ethyl ketone. That is, the evaluation result of the solvent resistance (methyl ethyl ketone resistance) was determined to be “◯”. Thereby, it was confirmed that the crosslinked polymer fine particles (PC-1) are fine particles having excellent solvent resistance due to the crosslinking effect.
The SEM image of the crosslinked polymer fine particles (PC-1) before being immersed in methyl ethyl ketone is shown in FIG. 3 (magnification 12,000 times), and after being immersed in methyl ethyl ketone for 24 hours and then dried and obtained. An SEM image of the fine particles (PC-1) is shown in FIG. 4 (magnification 8,000 times).

Examples 12 to 17 (Production of crosslinked polymer fine particles (PC-2) to (PC-7))
As the liquid containing the dispersion stabilizer, the dispersions (DS4), (DS5), (DS6) or (DS12) shown in Table 7 below were used, and the amounts of 25% aqueous ammonia, water and methanol used are shown in Table 7. In the same manner as in Example 11 except that the compound shown in Table 7 was used as the vinyl monomer in the amount shown in Table 7, crosslinked polymer fine particles (hereinafter referred to as “crosslinked polymer fine particles (PC- 2) to (PC-7)), and the polymerization stability was evaluated in the same manner as in Example 1. The results were as shown in Table 7.
The crosslinked polymer fine particles (PC-2) to (PC-7) obtained above were observed using an SEM in the same manner as in Example 11, and the volume average particle diameter ( dv), number average particle diameter (dn), and coefficient of variation (Cv) of the particle size were as shown in Table 7 below.
Moreover, when the amount of by-product small particles produced of 0.3 μm or less was determined from the SEM image, it was as shown in Table 7 below.
The crosslinked polymer fine particles (PC-2) to (PC-7) obtained above were tested for methyl ethyl ketone resistance in the same manner as in Example 11. After 24 hours, the crosslinked polymer fine particles (PC-) were tested. 2) to (PC-7) were precipitated in methyl ethyl ketone. However, there was no aggregation or coalescence between the particles, and they could be easily redispersed. The redispersed polymer fine particles (PC-2) to (PC-7) were taken out from methyl ethyl ketone and dried at room temperature. And when it observed using SEM similarly to the above, crosslinked polymer microparticles | fine-particles (PC-2)-(PC-7) are crosslinked polymer microparticles | fine-particles (PC-2) before being immersed in methyl ethyl ketone. There was no difference from ~ (PC-7). That is, the evaluation result of the solvent resistance (methyl ethyl ketone resistance) was determined to be “◯”.

Examples 18 to 21 (Production of crosslinked polymer fine particles (PC-8) to (PC-11))
The dispersion (DS4) or (DS13) shown in Table 8 below is used as the liquid containing the dispersion stabilizer, and the amounts of 25% aqueous ammonia, water and methanol used are shown in Table 8 below. In the same manner as in Example 11 except that the compounds shown in Table 8 were used in the amounts shown in Table 8, crosslinked polymer fine particles (hereinafter referred to as “crosslinked polymer fine particles (PC-8) to (PC-11)” were used. When the polymerization stability was evaluated in the same manner as in Example 1, it was as shown in Table 8.
The crosslinked polymer fine particles (PC-8) to (PC-11) obtained above were observed using SEM in the same manner as in Example 11. From the obtained SEM image, the volume average particle diameter ( dv), number average particle diameter (dn), and coefficient of variation (Cv) of particle size were as shown in Table 8 below.
Moreover, when the amount of by-product small particles produced of 0.3 μm or less was determined from the SEM image, it was as shown in Table 8 below.
The crosslinked polymer fine particles (PC-8) to (PC-11) obtained above were tested for methyl ethyl ketone resistance in the same manner as in Example 11. After 24 hours, the crosslinked polymer fine particles (PC-) 8) to (PC-11) were precipitated in methyl ethyl ketone. However, there was no aggregation or coalescence between the particles, and they could be easily redispersed. The redispersed polymer fine particles (PC-8) to (PC-11) were taken out from methyl ethyl ketone and dried at room temperature. And when it observed using SEM like the above, crosslinked polymer microparticles | fine-particles (PC-8)-(PC-11) are crosslinked polymer microparticles | fine-particles (PC-8) before being immersed in methyl ethyl ketone. There was no change from ~ (PC-11). That is, the evaluation result of the solvent resistance (methyl ethyl ketone resistance) was determined to be “◯”.

Examples 22 to 24 (Production of crosslinked polymer fine particles (PC-12) to (PC-14))
The kind of liquid containing the dispersion stabilizer and the amount of use thereof, and the amounts of 25% aqueous ammonia, water and methanol used are as shown in Table 8 below, and further, a crosslinkable monomer with methyl methacrylate and isobutyl methacrylate. Except that allyl methacrylate was used as a body in the amount shown in Table 8, crosslinked polymer fine particles (hereinafter referred to as “crosslinked polymer fine particles (PC-12) to (PC-14)) in the same manner as in Example 1. Then, the polymerization stability was evaluated in the same manner as in Example 1, and the results were as shown in Table 8.
The crosslinked polymer fine particles (PC-12) to (PC-14) obtained above were observed using an SEM in the same manner as in Example 11, and the volume average particle diameter ( dv), number average particle diameter (dn), and coefficient of variation (Cv) of particle size were as shown in Table 8 below.
Moreover, when the amount of by-product small particles produced of 0.3 μm or less was determined from the SEM image, it was as shown in Table 8 below.
The crosslinked polymer fine particles (PC-12) to (PC-14) obtained above were tested for methyl ethyl ketone resistance in the same manner as in Example 11. After 24 hours, the crosslinked polymer fine particles (PC-12) were tested. ) To (PC-14) were precipitated in methyl ethyl ketone. However, there was no aggregation or coalescence between the particles, and they could be easily redispersed. The redispersed polymer fine particles (PC-12) to (PC-14) were taken out from methyl ethyl ketone and dried at room temperature. And when it observed using SEM similarly to the above, crosslinked polymer microparticles | fine-particles (PC-12)-(PC-14) are crosslinked polymer microparticles | fine-particles (PC-12) before being immersed in methyl ethyl ketone. There was no difference from ~ (PC-14). That is, the evaluation result of the solvent resistance (methyl ethyl ketone resistance) was determined to be “◯”.
The SEM image of the crosslinked polymer fine particles (PC-13) of Example 23 before being immersed in methyl ethyl ketone is obtained by drying after being immersed in FIG. 5 (magnification 12,000 times) and in methyl ethyl ketone for 24 hours. An SEM image of the crosslinked polymer fine particles (PC-13) is shown in FIG. 6 (5,000 magnifications).

  As seen in the results of Table 7 and Table 8 above, in Examples 11 to 24, the volume average particle size (dv) is less than 2 μm and the particle size is extremely small by using a very small amount of the dispersion stabilizer. In addition, crosslinked polymer fine particles having excellent solvent resistance can be obtained smoothly with good polymerization stability without causing aggregation or the like between polymer fine particles with a narrow particle size distribution with a coefficient of variation (Cv) of particle size of 20% or less. I was able to get it.

Example 25 (Production of crosslinked polymer fine particles (PC-15))
In a glass reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube, 299 parts by mass of ion-exchanged water, 3.0 parts by mass of 10% KOH aqueous solution, and the polymer fine particles obtained in Example 1 A dispersion 285.7 obtained by removing a part of the volatile matter (water, methanol) from the dispersion of (PA-1) under reduced pressure so that the solid content concentration of the polymer fine particles (PA-1) is 35% by mass. The internal temperature of the reactor was adjusted to 20 ° C. while charging a mass part and stirring.
On the other hand, 50.0 parts by mass of methyl methacrylate and 50.0 parts by mass of ethylene glycol dimethacrylate were charged into a stainless steel container and mixed with stirring. Thereafter, an emulsifier obtained by dissolving 1.5 parts by mass of a 30% aqueous solution of sodium lauryl sulfate (trade name “Emar 2F-30”, manufactured by Kao Corporation) as an emulsifier in 100 parts by mass of ion-exchanged water. An aqueous solution was added and emulsified using an emulsifier to prepare an emulsion of a vinyl monomer mixture.
Next, an emulsion of the vinyl monomer mixture prepared above was added to the reactor, and 2,2′-azobis (2,4-dimethylvaleronitrile) (trade name “V- 65 ”(manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred for 12 hours at an internal temperature of the reactor of 20 ° C. Thereby, the vinyl monomer mixture and the polymerization initiator were absorbed into the polymer fine particles (PA-1).

Thereafter, the internal temperature was raised from 20 ° C. to 70 ° C. over 2 hours while nitrogen gas was blown into the mixed liquid in the reactor from a nitrogen introduction tube set above the liquid level of the reactor. Thereby, the vinyl monomer mixture absorbed in the polymer fine particles (PA-1) was polymerized. After reaching 70 ° C., the internal temperature was maintained at 70 ° C. for 2 hours, and then triethylene glycol bis (3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate) (as an antioxidant) A solution obtained by dissolving 1 part by mass of a trade name “AO-70” (manufactured by ADEKA) in 19 parts by mass of methanol was added, and the mixture was further maintained at 70 ° C. for 30 minutes. Thereafter, a dispersion of polymer fine particles (PC-15) crosslinked by cooling was produced.
Next, the dispersion liquid of the crosslinked polymer fine particles (PC-15) obtained above was subjected to a centrifugal separation treatment, and the supernatant was removed to collect the precipitated cake of the crosslinked polymer fine particles. The recovered crosslinked polymer fine particle (PC-15) sediment was mixed with the same mass of ion exchange water and redispersed. Then, the centrifugation process was performed again, the supernatant was removed, and sediment was collect | recovered. The recovered material was dried at 80 ° C. until the nonvolatile content when heated at 155 ° C. for 30 minutes was 98% by mass or more, and then crushed to produce crosslinked polymer fine particles (PC-15). .

SEM observation was performed about the crosslinked polymer microparticles | fine-particles obtained above (PC-15). From the obtained images, the volume average particle size (dv) was 1.79 μm, the number average particle size (dn) was 1.79 μm, and the coefficient of variation (Cv) in particle size was 4.9%.
The crosslinked polymer fine particles (PC-15) obtained above were tested for methyl ethyl ketone resistance in the same manner as in Example 11. After 24 hours, the crosslinked polymer fine particles (PC-15) were found to be methyl ethyl ketone. Sedimented in. However, there was no aggregation or coalescence between the particles, and they could be easily redispersed. The redispersed polymer fine particles (PC-15) were taken out from methyl ethyl ketone and dried at room temperature. And when it observed using SEM like the above, crosslinked polymer particulates (PC-15) are compared with crosslinked polymer particulates (PC-15) before being immersed in methyl ethyl ketone, Although some elution of the non-crosslinked polymer component was observed, it was found that the particle shape was maintained. That is, the solvent resistance (methyl ethyl ketone resistance) was improved by crosslinking.

  The present invention is a method for producing polymer fine particles by a dispersion polymerization method using a macromonomer (Ma) having a carboxyl group and an ethylenically unsaturated group in the middle of a molecular chain as a dispersion stabilizer. As a result, non-crosslinked polymer fine particles or crosslinked polymer having a very small particle size of micron size, a narrow particle size distribution and a uniform particle size, monodispersed and without aggregation between particles Fine particles can be produced smoothly and with good productivity. Of the polymer fine particles obtained by the method of the present invention, the crosslinked polymer fine particles are excellent in heat resistance, solvent resistance, chemical resistance, strength and the like. Therefore, the polymer fine particles obtained by the method of the present invention make use of the above-described excellent characteristics, and light diffusion agents such as liquid crystal display spacers, liquid crystal display light diffusion films, and diffusion plates, and liquid crystal display AGs. It can be effectively used for various applications including AG agents such as films, anti-blocking agents for various films, conductive fine particles, column fillers, diagnostic agents and the like.

Claims (11)

Polymer fine particles comprising a step of polymerizing a vinyl monomer in the presence of a dispersion stabilizer in a hydrophilic solvent that dissolves the vinyl monomer and the dispersion stabilizer but does not dissolve the produced polymer. A method of manufacturing
The dispersion stabilizer contains a polymer containing a macromonomer having a carboxyl group and an ethylenically unsaturated group in the middle of the molecular chain, and the polymer has an average of 0.2 to 1.74 per molecule. A method for producing polymer fine particles, which has one ethylenically unsaturated group .   The macromonomer is a polymer obtained by addition-reacting a compound having an epoxy group and an ethylenically unsaturated group to a part of the carboxyl group of the polymer (A) having a carboxyl group in the middle of the molecular chain. The method for producing polymer fine particles according to claim 1.   The method for producing polymer fine particles according to claim 2, wherein the polymer (A) is a polymer produced by emulsion polymerization. 4. The polymer fine particle according to claim 1, wherein the polymer in the dispersion stabilizer has an average of 0.2 to 1.6 ethylenically unsaturated groups per molecule. Production method.   The said dispersion stabilizer contains the polymer containing the said macromonomer, The average value of content of the carboxyl group in this polymer is 1-9 meq / g, The any one of Claims 1-4 The manufacturing method of the polymer fine particle of description.   The method for producing polymer fine particles according to claim 1, wherein the macromonomer contains a (meth) acryloyl group.   The said vinyl monomer contains the vinyl monomer which has a hydrolyzable silyl group at least, and manufactures the microparticles | fine-particles which consist of a polymer which has a hydrolyzable silyl group. A method for producing polymer fine particles.   Furthermore, the manufacturing method of the polymer microparticles | fine-particles of Claim 7 which comprises the process of hydrolyzing and condensing the hydrolysable silyl group in the polymer of Claim 7, and manufacturing the microparticles | fine-particles which consisted of the crosslinked polymer.   The method for producing polymer fine particles according to any one of claims 1 to 7, wherein the vinyl monomer contains at least a polyfunctional vinyl monomer having two or more ethylenically unsaturated groups.   Furthermore, after the polymer fine particles obtained by the production method according to any one of claims 1 to 6 are absorbed with a vinyl monomer containing a polyfunctional vinyl monomer, they are polymerized and crosslinked. The method for producing polymer fine particles according to any one of claims 1 to 6, wherein the polymer fine particles are produced.   Polymer fine particles obtained by the production method according to any one of claims 1 to 10, wherein the volume average particle diameter is 0.7 to 2.0 µm, and the coefficient of variation in particle size is 20% or less. Polymer fine particles characterized by the above.