JPWO2021171669A5 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to polymer particles obtained by a polymerization reaction and surface-active agent-modified polymer particles, and uses thereof. In particular, polymer particles that are suitably used as raw materials for optical members such as light diffusion films and antiglare films, and uses of these polymer particles (optical members, paint additives and anti-blocking agents: films and resin moldings containing these ), and a method for producing the polymer particles.

Polymer particles having a volume average particle diameter of 1 to 100 μm are used, for example, as additives for coating agents such as paints (matting agents, etc.), additives for inks (matting agents, etc.), main components of adhesives or Additives, additives for artificial marble (low shrinkage agents, etc.), paper treatment agents, fillers for external agents such as cosmetics (fillers for improving lubricity), column fillers used in chromatography, static charge It is used in applications such as additives for toner used in image development, anti-blocking agents for films, and light diffusion agents for optical members (optical films such as light diffusion films and anti-glare films, light diffusers, etc.). ing.

Such polymer particles can be produced by polymerizing polymerizable monomers. Suspension polymerization, seed polymerization, emulsion polymerization and the like are known as polymerization methods for polymerizing polymerizable monomers. In these polymerization methods, a surfactant is usually used so that the polymerization reaction can be stably performed and the generation of coarse particles can be suppressed.

For example, Patent Document 1 describes polymer particles composed of at least one of a (meth)acrylic polymer, a styrene polymer, and a (meth)acrylic-styrene copolymer. The polymer particles have a coefficient of variation of particle diameter of 15.0% or less, and a content of the surfactant having a polyoxyalkylene chain per unit surface area of the polymer particles of 2.0 to 15.0×10. ⁻³ g/m ² , and the content of the other surfactant per unit surface area of the polymer particles is 10.0×10 ⁻⁵ g/m ² or less.

In Patent Document 2, it is obtained by polymerizing a vinyl-based monomer in a medium containing a surfactant (another surfactant without a polyoxyalkylene chain in the examples), and is used as a light diffusing agent. Polymer particles are described. The amount of residual surfactant in these polymer particles is 0.05 parts by mass or less (0.005 to 0.036 parts by mass in the examples) with respect to 100 parts by mass of the fine resin particles.

WO2016/051814 JP 2006-233055 A

2. Description of the Related Art Optical films such as light diffusion films and anti-glare films are known in which a film substrate is coated with a resin composition containing polymer particles, a binder and an organic solvent.
When an optical film is produced in this manner, the polymer particles must be uniformly and stably dispersed in the resin composition and in the dry coating film obtained therefrom so as to obtain stable optical properties. . Furthermore, the time required for the polymer particles to uniformly and stably disperse in the resin composition is preferably as short as possible from the viewpoint of productivity.

The polymer particles disclosed in Patent Document 1 have a resin composition depending on the type of other surfactant contained in the polymer particles, the surface residue amount thereof, and the surface residue amount of non-volatile components contained in the polymer particles. The time required for uniform and stable dispersion of the polymer particles in the material can be lengthened.
When the polymer particles disclosed in Patent Document 2 are coated with the resin composition on a film substrate to form a coating film, the dispersed state of the polymer particles in the resin composition is not stable and uneven. As a result, local aggregation may occur.
As a result, the polymer particles do not spread uniformly over the entire coating film formed on the film substrate, and the optical properties of the optical film become non-uniform. rice field.

The present invention has been made in view of the above situation, and polymer particles that are uniformly and stably dispersed (excellent in dispersibility and dispersion stability) in a resin composition and in a dry coating film obtained therefrom. It is an object of the present invention to provide polymer particles in which the time required for the polymer particles to uniformly and stably disperse in a resin composition is short.

As a result of intensive studies in view of the above problems, the present inventors have found that in a resin composition containing polymer particles, the dispersion stability of the polymer particles is correlated with the change in viscosity over time.
In order to improve the dispersion stability and shorten the time until the dispersion stabilizes, the type and solubility parameter (SP value) of the surfactant contained in the polymer particles, the surface residue amount thereof, and the amount of non-volatile components It is important to optimize the surface residue amount, so that it can be uniformly and stably dispersed in the resin composition containing the polymer particles and in the dry coating film obtained therefrom (in terms of dispersibility and dispersion stability The inventors have found that polymer particles can be obtained, and have completed the present invention.

Specifically, the present invention is as follows.
[1]
(a) The content of the surfactant having a solubility parameter (SP value) of 9.0 to 12.0 and having a polyoxyalkylene chain is 1.0×10 ⁻³ to 6.0×10 −3 per unit surface area of the polymer particles. 0×10 ⁻³ g/m ² ,
(b) the content of the surfactant having a solubility parameter (SP value) of 9.0 to 12.0 and having no polyoxyalkylene chain is 5.0 × 10 ^-5 to 13 per unit surface area of the polymer particle; .0×10 ⁻⁵ g/m ² ,
(c) the surface residual amount of non-volatile components is 2.0×10 ⁻³ g/m ² or less per unit surface area of the polymer particles;
is a polymer particle.
[2]
The polymer particles according to [1], which have a volume average particle diameter of 1 to 20 μm and a coefficient of variation (CV value) of 15% or less for the particle diameter of the polymer particles obtained by the following formula.
Variation coefficient (CV value) of particle size of polymer particles = (standard deviation of volume-based particle size distribution of polymer particles/volume average particle size of polymer particles) x 100
[3]
The polymer particles of [1] or [2], wherein the surfactant having a polyoxyalkylene chain with an SP value of 9.0 to 12.0 is a phosphate ester anionic surfactant.
[4]
Any one of [1] to [3] composed of one or more polymers selected from the group consisting of (meth)acrylic polymers, styrene polymers, and (meth)acrylic-styrene copolymers polymer particles.
[5]
A polymer particle according to any one of [1] to [4], which is used for an optical member.
[6]
A polymer particle according to any one of [1] to [4], which is used as an additive for paints.
[7]
A polymer particle according to any one of [1] to [4], which is used as an antiblocking agent.
[8]
[1] to [4] A resin composition containing the polymer particles and a resin binder.
[9]
An optical member having a layer of the resin composition of [8] on a substrate.

The polymer particles of the present invention are excellent in dispersibility and dispersion stability in the resin composition when a resin composition containing the polymer particles, a binder and an organic solvent is formed, and The time required for uniformly and stably dispersing the polymer particles is shortened, resulting in excellent workability.
In addition, since the dispersibility and dispersion stability of the polymer particles are maintained even when the resin composition is applied to form a coating film, excessive aggregation of the polymer particles during coating film formation is suppressed. be able to. For this reason, the polymer particles uniformly spread over the entire coating film formed on the film base material, and provide the coating film with uniform and stable optical properties such as light diffusion and antiglare properties. can.
Furthermore, the type of surfactant contained in the polymer particles (e.g., the presence or absence of a polyoxyalkylene chain, the solubility parameter (SP value) of the surfactant, etc.), the amount of surfactant per unit surface area of the polymer particles, In addition, it is possible to adjust the dispersibility of the polymer particles in the resin composition by adjusting the surface residual amount of the non-volatile component per unit surface area of the polymer particles. Therefore, it is not necessary to change the monomer composition of the polymer particles for adjusting the dispersibility of the polymer particles and to adjust the refractive index accordingly, which has been conventionally performed, and the workability can be further improved.
Furthermore, since the polymer particles of the present invention have a small difference in surface state between polymer particles, when a resin composition is formed by mixing with a resin binder and an organic solvent, the polymer particles are uniformly dispersed in the resin composition. It will be excellent in quality. In addition, since it is possible to reduce temporal changes in the surface state of the polymer particles and differences in the surface state between production lots of the polymer particles, the quality stability is excellent, and the dispersion state between production lots of the resin composition is improved. difference is small, and the dispersion stability is excellent.

[Polymer particles]
In the present invention, the solubility parameter (SP value) is the various atomic groups according to Okitsu described in Table 1 below, described in Toshinao Okitsu, "Adhesion", Kobunshi Kankokai, Vol. 40, No. 8 (1996), p. 342-350 means the solubility parameter δ calculated by the following formula (1) using the ΔF and Δv values of In the case of mixed solvents and copolymers, it means the solubility parameter δ calculated by the following formula (2).
δ=ΣΔF/ΣΔv (1)
δmix=φ1δ1+φ2δ2+...φnδn (2)
In formula (1), ΔF represents ΔF in Table 1 below, and Δv represents molar volume Δv in Table 1 below. In formula (2), φ represents a volume fraction or a molar fraction, and φ1+φ2+ . . . φn=1.

本明細書中においては、上記により算出される溶解度パラメータを、単にＳＰ値という場合がある。
以下、本発明について詳細に説明する。

In this specification, the solubility parameter calculated as described above may be simply referred to as the SP value.
The present invention will be described in detail below.

<Polymer>
The polymer constituting the polymer particles of the present invention is not particularly limited, and examples include vinyl polymers (acrylic polymers, styrene polymers, acrylic styrene polymers, olefin polymers, vinyl polymers, etc.), polyester-based polymers, polyamide-based polymers, polyurethane-based polymers, and the like.
Among these, a vinyl polymer which is a copolymer of a monofunctional vinyl monomer having one ethylenically unsaturated group and a polyfunctional vinyl monomer having two or more ethylenically unsaturated groups is preferred.

(Monofunctional vinyl monomer)
Examples of the monofunctional vinyl-based monomers include (meth)acrylic acid ester-based monomers, aromatic vinyl-based monomers, fatty acid vinyl ester-based monomers, halogenated olefin-based monomers, cyanide From vinyl-based monomers, unsaturated carboxylic acid-based monomers, unsaturated polycarboxylic acid ester-based monomers, unsaturated carboxylic acid amide-based monomers, unsaturated carboxylic acid amide-based methylol compound-based monomers, etc. One or more selected from the group consisting of can be used.
In the present specification, the (meth)acrylic acid ester-based monomer means an acrylic acid ester-based monomer or a methacrylic acid ester-based monomer.
Examples of (meth)acrylic acid ester-based monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and (meth)acrylic acid. Alkyl (meth)acrylate monomers such as 2-ethylhexyl, n-octyl (meth)acrylate, isononyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate, glycidyl (meth)acrylate (Meth)acrylic acid esters having an epoxy group (glycidyl group) such as acrylate, hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, dimethylaminoethyl (meth) At least one selected from the group consisting of (meth)acrylic acid esters having an amino group such as acrylates and diethylaminoethyl (meth)acrylate.

Examples of aromatic vinyl-based monomers include one or more selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, ethylvinylbenzene, and the like.
As the fatty acid vinyl ester-based monomer, for example, one or more selected from the group consisting of vinyl acetate, vinyl propionate, vinyl versatate and the like can be used.
As the halogenated olefinic monomer, for example, one or more selected from the group consisting of vinyl chloride, vinylidene chloride, tetrafluoroethylene, vinylidene fluoride and the like can be used.
As the vinyl cyanide-based monomer, for example, one or more selected from the group consisting of (meth)acrylonitrile and the like can be used.
The unsaturated carboxylic acid-based monomers include unsaturated carboxylic acids, salts or anhydrides thereof, such as (meth)acrylic acid, crotonic acid, citraconic acid, itaconic acid, maleic acid, fumaric acid, One or more selected from the group consisting of ammonium, metal salts, maleic anhydride and the like thereof can be used.

The unsaturated polycarboxylic acid ester monomers include unsaturated dicarboxylic acid monoesters, salts thereof, and unsaturated dicarboxylic acid diesters. Examples include monobutyl maleic acid, their ammonium and metal salts, maleic acid One or more selected from the group consisting of dimethyl and the like can be used.
As the unsaturated carboxylic acid amide-based monomer, for example, one or more selected from the group consisting of (meth)acrylamide, diacetone(meth)acrylamide, and the like can be used.
Examples of unsaturated carboxylic acid amide methylolated monomers include N-methylolacrylamide, N-methylolmethacrylamide, methylolated diacetoneacrylamide, and these monomers and alcohols having 1 to 8 carbon atoms. One or more selected from the group consisting of etherified products of (eg, N-isobutoxymethylacrylamide) can be used.

(Polyfunctional vinyl-based monomer)
The polyfunctional vinyl-based monomer is not particularly limited as long as it is a monomer having two or more ethylenically unsaturated groups. For example, allyl (meth)acrylate, divinylbenzene, diallyl phthalate, triallyl cyanurate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, triethylene glycol di(meth) One or more selected from the group consisting of acrylates, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate and the like can be used.

The polymer particles of the present invention are preferably composed of at least one type of polymer selected from (meth)acrylic polymers, styrene polymers and (meth)acrylic-styrene copolymers. Thereby, polymer particles having high light transmittance can be realized.
(Meth)acrylic polymer is a polymer of (meth)acrylic acid ester-based monomer, or (meth)acrylic acid ester-based monomer, (meth)acrylic acid ester-based monomer and styrene It is a copolymer with a vinyl monomer other than a monomer.
Styrenic polymers are polymers of styrene monomers, or copolymers of styrene monomers with vinyl monomers other than (meth)acrylic acid ester monomers and styrene monomers. It is a coalescence.
(Meth) acrylic - styrene copolymer is a copolymer of a (meth) acrylic ester monomer and a styrene monomer, or a (meth) acrylic ester monomer and a styrene It is a copolymer of a monomer and other vinyl monomers.

Among these, polymer particles composed of a (meth)acrylic-styrene copolymer are preferred from the viewpoint of light diffusion and antiglare properties, and polymers having a specific gravity of more than 1.0 are more preferred. .
Here, the specific gravity of the polymer particles is a measured value obtained by measuring according to A method in JIS K5101-11-1.
Specifically, the specific gravity was measured in a temperature-controlled room at 20°C as follows.
A Wardon-type pycnometer having an internal capacity of 50 ml was completely filled with ethanol, and the mass of the pycnometer including the contents at this time was weighed and designated as A (g).
Next, after the ethanol in the pycnometer was emptied, about 3 g of polymer particles as a sample was transferred into the pycnometer, and the mass of the transferred polymer particles was weighed and designated as B (g).
Additional ethanol was added into the pycnometer to completely fill the pycnometer with polymer particles and ethanol. The mass of the pycnometer including the contents at this time was defined as Cg.
The specific gravity of the polymer particles was calculated by the following formula.
Specific gravity (g/ml) = B x 0.7950/(AC + B)

Moreover, the polymer constituting the polymer particles is preferably a copolymer (crosslinked polymer) of a monofunctional vinyl-based monomer and a polyfunctional vinyl-based monomer. In the present invention, it is particularly preferable that the polymer constituting the polymer particles is a (meth)acrylic-styrene crosslinked polymer from the viewpoint of light diffusion and antiglare properties.
The amount of structural units derived from a polyfunctional vinyl monomer in the crosslinked polymer is 1 to 70% by mass, preferably 3 to 60% by mass, more preferably 5 to 50% by mass with respect to 100% by mass of the crosslinked polymer. %.
If the amount of structural units derived from the polyfunctional vinyl-based monomer is less than 1% by mass, the degree of cross-linking of the polymer will be low. Therefore, when the polymer particles are mixed with a binder and a solvent to form a resin composition, the polymer particles swell, increasing the viscosity of the resin composition and possibly reducing the coating workability. Furthermore, as a result of the decrease in the degree of cross-linking of the polymer, in applications where the polymer particles are mixed with a binder and molded (so-called kneading applications), when heat is applied to the polymer particles during mixing or molding, the polymer Particles become more susceptible to dissolution or deformation.
If the amount of structural units derived from the polyfunctional vinyl monomer is more than 70% by mass, an improvement in the effects commensurate with the amount of the polyfunctional vinyl monomer used may not be observed, and production costs may increase. be.

<Surfactant having a polyoxyalkylene chain with an SP value of 9.0 to 12.0>
In a surfactant having a polyoxyalkylene chain with an SP value of 9.0 to 12.0, the SP value range is more preferably 9.1 to 11.9, more preferably 9.3 to 11.7. , most preferably between 9.6 and 11.2.
The alkylene group in the polyoxyalkylene chain includes, for example, an alkylene group having 2 to 6 carbon atoms, preferably an ethylene group, a propylene group, a trimethylene group or a butylene group, and particularly preferably an ethylene group.
As a surfactant having a polyoxyalkylene chain with an SP value of 9.0 to 12.0, if the SP value is within the range of 9.0 to 12.0, anionic, cationic, nonionic and amphoteric any surfactant.
In the present invention, it is possible to ensure more stable dispersion of the vinyl-based monomer in the liquid medium and to obtain polymer particles having a uniform particle diameter when the vinyl-based monomer is polymerized. Therefore, at least one of an anionic surfactant and a nonionic surfactant is preferable, and at least an anionic surfactant having a polyoxyalkylene chain is more preferably used. This makes it possible to prevent aggregation during the polymerization reaction and ensure dispersion stability.

As an anionic surfactant having a polyoxyalkylene chain, any of known anionic surfactants such as fatty acid salt type, sulfate type, sulfonate type, phosphate ester salt type, and phosphate ester type can be used. can be used.
For example, polyoxyethylene alkyl phenyl ether sulfate salts, polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene alkyl sulfates, polyoxyethylene styrenated phenyl ether sulfate ammonium, etc. Ethylene styrenated phenyl ether sulfates, polyoxyethylene alkylphenyl ether phosphates such as polyoxyethylene nonyl phenyl ether phosphates (e.g. sodium polyoxyethylene nonyl phenyl ether phosphate), polyoxyethylene styrenated phenyl ether phosphates One or more selected from the group consisting of acid esters, polyoxyethylene alkyl ether phosphates, and the like can be used.

As the nonionic surfactant having a polyoxyalkylene chain, any of known nonionic surfactants such as ester type, ether type and ester/ether type can be used.
For example, polyoxyethylene alkyl ether such as polyoxyethylene tridecyl ether, polyoxyethylene alkylphenyl ether such as polyoxyethylene octylphenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene monolaurate At least one selected from the group consisting of polyoxyethylene sorbitan fatty acid esters such as sorbitan, polyoxyethylene alkylamines, oxyethylene-oxypropylene block polymers, and the like can be used.

Among these, polyoxyethylene alkylphenyl ether phosphates such as polyoxyethylene nonylphenyl ether phosphate (e.g. sodium polyoxyethylene nonylphenyl ether phosphate), polyoxyethylene styrenated phenyl ether phosphate, polyoxyethylene It is preferable to use one or more phosphate anionic surfactants such as ethylene alkyl ether phosphate. Examples of such phosphate-based anionic surfactants include Plysurf (AL, A210G, A208F, etc.) manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and Phosphanol (LO-529, etc.) manufactured by Toho Chemical Industry Co., Ltd. One or more kinds selected from commercially available products such as and salts thereof can be used.

The content of the surfactant having a polyoxyalkylene chain with an SP value of 9.0 to 12.0 is 1.0×10 ⁻³ to 6.0×10 ⁻³ g/m ² per unit surface area of the polymer particles. , preferably 1.1×10 ⁻³ to 4.25×10 ⁻³ g/m ² , more preferably 1.4×10 ⁻³ to 2.8×10 ⁻³ g/m ² . Thereby, when a resin composition containing polymer particles is formed, the dispersibility and dispersion stability of the polymer particles can be enhanced. Moreover, it is possible to adjust the dispersibility and the dispersion stability without changing the monomer composition of the polymer particles.
The present inventors found that the content of a surfactant having a polyoxyalkylene chain with an SP value of 9.0 to 12.0 is 4.4 × 10 ^-3 to 6.0 per unit surface area of the polymer particles. ×10 ⁻³ g/m ² , the dispersibility and dispersion stability of the polymer particles can be improved when a resin composition containing the polymer particles is formed. We have found that it is possible to adjust the dispersibility and dispersion stability without changing the monomer composition.

There are no particular restrictions on the means for incorporating a surfactant having a polyoxyalkylene chain with an SP value of 9.0 to 12.0 into the polymer particles. Examples thereof include a method of mixing polymer particles and a surfactant, and a method of allowing a surfactant to coexist during the formation of polymer particles.
In the present invention, in particular, a vinyl-based polymer is polymerized in the presence of a surfactant having a polyoxyalkylene chain, and the content is adjusted as necessary to form a polyoxyalkylene chain on the polymer particles. It is preferable to use a method of containing (remaining) a surfactant having

In particular, it is preferable to carry out seed polymerization in the presence of seed particles, a vinyl-based monomer and a surfactant having a polyoxyalkylene chain, and adjust the content in a washing step or the like. Polymer particles obtained by seed polymerization have little variation in particle size, and when used for optical members such as anti-glare films and light diffusion films, improve optical properties such as anti-glare properties and light diffusion properties of optical members. can be made

<Surfactant not having a polyoxyalkylene chain with an SP value of 9.0 to 12.0>
In a surfactant having no polyoxyalkylene chain with an SP value of 9.0 to 12.0, the SP value range is more preferably 9.0 to 11.8, more preferably 9.1 to 11.5. Yes, most preferably between 9.2 and 11.4.
As a surfactant having no polyoxyalkylene chain with an SP value of 9.0 to 12.0, if the SP value is within the range of 9.0 to 12.0, anionic, cationic, nonionic and both Any ionic surfactant may be used.
In the present invention, when a vinyl monomer is polymerized in the presence of a surfactant, the dispersion of the vinyl monomer in the liquid medium can be more stably ensured, and the particle diameter can be reduced. It is more preferable to use at least one of an anionic surfactant and a nonionic surfactant, since uniform polymer particles can be obtained. This makes it possible to prevent aggregation during the polymerization reaction and ensure dispersion stability.

As the anionic surfactant not having a polyoxyalkylene chain, any of known anionic surfactants such as fatty acid salt type, sulfate ester salt type, sulfonate type, and phosphate ester salt type can be used. .
For example, sodium oleate, fatty acid soaps such as castor oil potash soaps, alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, alkylnaphthalenesulfonates, and alkanesulfonates , di(2-ethylhexyl) sodium sulfosuccinate, dialkyl sulfosuccinate such as sodium dioctyl sulfosuccinate, alkenyl succinate such as (mono or di)sodium alkenyl succinate, alkyl phosphate ester salt, naphthalene sulfonic acid formalin condensate One or more selected from the group consisting of can be used.

As the nonionic surfactant having no polyoxyalkylene chain, any of known nonionic surfactants such as ester type, ether type and ester/ether type can be used.
For example, a group consisting of polyoxyalkylene alkyl ethers such as polyoxyalkylene tridecyl ethers in which the alkylene group has 3 or more carbon atoms, sorbitan fatty acid esters, glycerin fatty acid esters, isopropyl palmitate, fatty acid esters such as sorbitan trioleate, and the like. One or more selected from can be used.

As the cationic surfactant not having a polyoxyalkylene chain, any of known cationic surfactants such as amine salt type and quaternary ammonium salt type can be used. Activators are advantageous in terms of their handling.
For example, alkylamine salts such as laurylamine acetate and stearylamine acetate, alkyltrimethylammonium chlorides such as lauryltrimethylammonium chloride, hexadecyltrimethylammonium chloride, cocoyltrimethylammonium chloride and dodecyltrimethylammonium chloride, hexadecyldimethylbenzylammonium chloride, lauryl One or more selected from the group consisting of alkyldimethylbenzylammonium chloride such as dimethylbenzylammonium chloride can be used.

Amphoteric surfactants having no polyoxyalkylene chain include, for example, one or more selected from the group consisting of lauryl dimethylamine oxide, phosphate surfactants, phosphite ester surfactants, and the like. can be used.

Among these, di(2-ethylhexyl)sodium sulfosuccinate and other dialkylsulfosuccinates, alkenylsuccinates (mono- or di)sodium alkenylsuccinates, alkyl phosphates, alkyl sulfates such as sodium lauryl sulfate One or more polyoxyalkylene chain-free anionic surfactants selected from the group consisting of salts, and one or more polyoxygens selected from the group consisting of fatty acid esters such as isopropyl palmitate and sorbitan trioleate. It is preferable to use one or more nonionic surfactants having no alkylene chain.

The content of the surfactant having no polyoxyalkylene chain with an SP value of 9.0 to 12.0 is 5.0×10 ⁻⁵ to 13.0×10 ⁻⁵ g/m per unit surface area of the polymer particles. ² , preferably 5.2×10 ⁻⁵ to 12.7×10 ⁻⁵ g/m ² , particularly preferably 7.3×10 ⁻⁵ to 10.4×10 ⁻⁵ g/m ² . Thereby, when a resin composition containing polymer particles is formed, the dispersibility and dispersion stability of the polymer particles can be enhanced. Moreover, it is possible to adjust the dispersibility and dispersion stability without changing the monomer composition of the polymer particles.

There is no particular limitation on the means for incorporating a surfactant having an SP value of 9.0 to 12.0 and having no polyoxyalkylene chain into the polymer particles. Examples thereof include a method of mixing polymer particles and a surfactant, and a method of allowing a surfactant to coexist during the formation of polymer particles.
In the present invention, in particular, the vinyl polymer is polymerized in the presence of a surfactant, and the content is adjusted as necessary to allow the polymer particles to contain (remain) the surfactant. It is preferred to use the method.
In particular, it is preferable to carry out seed polymerization in the presence of seed particles, a vinyl-based monomer and a surfactant, and adjust the content by a washing step or the like. Polymer particles obtained by seed polymerization have little variation in particle size, and when used for optical members such as anti-glare films and light diffusion films, improve optical properties such as anti-glare properties and light diffusion properties of optical members. can be made

<Non-volatile component>
The non-volatile component in the polymer particles of the present invention means a non-volatile component contained in the supernatant after the polymer particles are dispersed in water and centrifuged to separate the polymer particles and the supernatant.
Specifically, 15.0 g of water was added to 5.0 g of polymer particles, and dispersion treatment was performed for 60 minutes using an ultrasonic cleaner to disperse the polymer particles in water. A non-volatile component contained in the supernatant collected after centrifugation using a centrifuge with a K factor of 6943 and a rotation time of 30 minutes.

Such a non-volatile component is a component that does not dissipate and remains even after heating at 110° C. and 1 atm for 10 hours. For example, when the polymer particles are obtained by seed polymerization, by-products such as polymerization products obtained by polymerizing monomers that have not been absorbed by the seed particles correspond. For example, minute components having a diameter of 1 μm or less contained in polymer particles may be mentioned.

The amount of residual non-volatile components on the surface of the polymer particles is obtained by using the content of the non-volatile components in the polymer particles and the specific surface area of the polymer particles, and the surface area of the non-volatile components per unit surface area of the polymer particles according to the following formula. A residue amount is calculated.
Surface residue amount of non-volatile components per unit surface area of polymer particles (g/m ² ) = (content of non-volatile components in polymer particles (g/1 g of polymer particles)/specific surface area of polymer particles ( ^m2 /g)
The surface residual amount of non-volatile components in the polymer particles of the present invention is 2.0×10 ⁻³ g/m ² or less, preferably 0.01×10 ⁻³ to 2.0× per unit surface area of the polymer particles. 10 ⁻³ g/m ² , more preferably 0.04×10 ⁻³ to 1.95×10 ⁻³ g/m ² , still more preferably 0.7×10 ⁻³ to 1.3×10 ⁻³ g / ^m2 .
This makes it possible to reduce variations in the amount of non-volatile components present on the surface of each polymer particle, and when the polymer particles are dispersed in a medium, particularly in a mixture of an organic solvent and a binder, Dispersion uniformity can be improved.

<Volume average particle size>
The volume average particle diameter of the polymer particles of the invention is, for example, 1 to 20 μm, preferably 1.5 to 15 μm, more preferably 1.5 to 10 μm. As a result, when the polymer particles are used in an optical member such as an antiglare film or a light diffusion film, optical properties such as antiglare property and light diffusion property of the optical member can be improved.
In the present invention, the volume average particle diameter of polymer particles refers to the arithmetic mean of the volume-based particle size distribution measured by the Coulter method, for example, the method described in the Examples.

<Coefficient of variation of particle size (CV value)>
The coefficient of variation (CV value) of the particle size of the polymer particles of the present invention is determined by the following formula.
Variation coefficient (CV value) of particle size of polymer particles = (standard deviation of volume-based particle size distribution of polymer particles/volume average particle size of polymer particles) x 100
The coefficient of variation (CV value) of the particle size in the present invention is preferably 15% or less, more preferably 12% or less, still more preferably 11% or less. Thereby, the dispersion uniformity of the polymer particles can be further improved.

<Gel fraction>
The gel fraction of the polymer particles of the present invention is 90% or more, preferably 94% or more, more preferably 96% or more, still more preferably 97% or more.
If the gel fraction is less than 90%, sufficient solvent resistance cannot be ensured. When forming an optical film such as a diffusion film, the polymer particles may be dissolved in an organic solvent, resulting in insufficient optical properties such as light diffusing properties and antiglare properties. In addition, the gel fraction in this specification shall refer to the gel fraction measured, for example by the method described in the Example.

<Refractive index>
The refractive index of the polymer particles of the invention is preferably 1.490 to 1.600. As a result, the polymer particles having the above configuration exhibit good optical properties (e.g., light transmittance, antiglare properties, light diffusion properties, etc.) when used in optical members such as antiglare films and light diffusion films. It is possible to realize an optical member having
Until now, polymer particles produced from a homopolymer having a high refractive index (e.g., a styrene-based monomer) and a highly hydrophilic monomer have generally used a highly hydrophilic monomer. Because of the low refractive index of homopolymers (for example, 1.488 or less), it has been difficult to achieve polymer particles with a refractive index of 1.570 to 1.600. In contrast, the polymer particles of the present invention can impart hydrophilicity to the polymer particles without requiring the addition of highly hydrophilic monomers. Hydrophilic polymer particles can be easily obtained.

[Method for producing polymer particles]
Examples of the method for producing the polymer particles of the present invention include a method of mixing the polymer particles and a surfactant, and a method of allowing the surfactant to coexist during the formation of the polymer particles.
In the present invention, in particular, the vinyl polymer is polymerized in the presence of a surfactant, and the content is adjusted as necessary to allow the polymer particles to contain (remain) the surfactant. It is preferred to use the method.
In particular, (i) a surfactant having an SP value of 9.0 to 12.0 and having a polyoxyalkylene chain in a liquid medium and a surfactant having an SP value of 9.0 to 12.0 and having a polyoxyalkylene chain a polymerization step of polymerizing a vinyl-based monomer in the presence of a surfactant containing a surfactant to obtain a crude product containing the polymer particles containing the surfactant and the medium; ) A solid-liquid separation step in which the crude product is put into a filter, the medium contained in the crude product is passed through the filter medium of the filter and removed, and the polymer particles contained in the crude product are retained on the filter medium. (iii) A washing liquid is introduced into the filter holding the polymer particles on the filter medium, and the polymer particles on the filter medium and the washing liquid are brought into contact with each other. A method comprising a washing step to obtain polymer particles on a filter medium, (iv) optionally a drying step and/or a classifying step is preferred.

As the polymerization step (i), it is particularly preferable to carry out seed polymerization in the presence of seed particles, a vinyl-based monomer and a surfactant, and adjust the content by a washing step or the like. Polymer particles obtained by seed polymerization have little variation in particle size, and when used for optical members such as anti-glare films and light diffusion films, improve optical properties such as anti-glare properties and light diffusion properties of optical members. can be made

Further, in the production of the polymer particles of the present invention, the solid-liquid separation step and washing step can affect the uniformity of the amount of residual components on the surface of the polymer particles and the resulting uniformity of the surface condition. If these steps become unstable, unnecessary portions of the surfactant used in the production of the polymer particles (surfactants having surplus polyoxyalkylene chains that do not contribute to modification of the polymer particle surface and Other surfactants used as necessary) and polymer dispersion stabilizers used as necessary have an adverse effect on the removal, and the amount of residual components on the surface of the polymer particles varies.
Each step of the method for producing polymer particles of the present invention will be described in detail below.

<Polymerization process>
In the polymerization step, in a liquid medium, a surfactant having an SP value of 9.0 to 12.0 and a polyoxyalkylene chain, and a surfactant having an SP value of 9.0 to 12.0 and not having a polyoxyalkylene chain a step of polymerizing a vinyl-based monomer in the presence of a surfactant containing a surfactant to obtain a crude product containing polymer particles containing the surfactant and the medium.

Any of water, organic solvents, and mixtures thereof can be used as the liquid medium. In the present invention, an aqueous medium is preferable, and for example, water, lower alcohols having 5 or less carbon atoms such as methyl alcohol and ethyl alcohol, mixtures of water and lower alcohols, and the like can be used.
As a surfactant having a polyoxyalkylene chain with an SP value of 9.0 to 12.0, a surfactant having a polyoxyalkylene chain with an SP value of <9.0 to 12.0 in the [polymer particles] Agent> is used.
As a surfactant having an SP value of 9.0 to 12.0 and having no polyoxyalkylene chain, the above [polymer particles] <SP value 9.0 to 12.0 does not have a polyoxyalkylene chain Surfactant> is used.
As the vinyl-based monomer and its composition, the vinyl-based monomer and its composition described in <Polymer> in the above [Polymer particles] are used.

A surfactant having an SP value of 9.0 to 12.0 and having a polyoxyalkylene chain and an SP value of 9.0 to 12.0 and having no polyoxyalkylene chain in the polymerization of vinyl monomers The amount of surfactant used is not particularly limited, but the total amount of surfactant is 0.01 to 10 parts by mass, preferably 0.01 to 5 parts by mass, per 100 parts by mass of the vinyl monomer. Further, it is preferable that a surfactant having an SP value of 9.0 to 12.0 and having a polyoxyalkylene chain is contained in an amount of 50 to 99% by mass, preferably 70 to 99% by mass, based on the entire surfactant.
If the total amount of the surfactant is less than the above range, the polymerization stability may be lowered, and it may be difficult to control the amount of the surfactant contained in the polymer particles. Further, if the amount of the surfactant used is more than the above range, it is uneconomical in terms of cost, and it becomes difficult to adjust the amount of each surfactant contained in the polymer particles within the specified range. may become

In the present invention, dispersion stability during polymerization of the vinyl-based monomer in the liquid medium can be ensured, and polymer particles having a uniform particle size can be obtained. Therefore, the SP value is 9.0 to 12. An anionic surfactant having a polyoxyalkylene chain with an SP value of .0 and a nonionic surfactant having an SP value of 9.0 to 12.0 and having a polyoxyalkylene chain are used at least.

The polymerization method of the vinyl monomer is not particularly limited as long as it is a known polymerization method using a liquid medium and a surfactant. For example, methods such as emulsion polymerization, suspension polymerization, and seed polymerization can be used.
Emulsion polymerization involves mixing a liquid medium, a vinyl-based monomer that is difficult to dissolve in this medium, and a surfactant (emulsifier), and then adding a polymerization initiator that is soluble in the medium to carry out polymerization. Legal. Emulsion polymerization can reduce the variation in particle size of the resulting polymer particles.
Suspension polymerization is a polymerization method in which a vinyl-based monomer and an aqueous medium such as water are mechanically stirred to suspend the vinyl-based monomer in the aqueous medium for polymerization. By suspension polymerization, polymer particles having a small particle size and relatively regular particle size can be obtained.

Seed polymerization is a method in which seed particles made of a polymer of vinyl monomers separately prepared are added to initiate polymerization of vinyl monomers.
For example, polymer particles made of a vinyl monomer polymer are used as seed particles, the vinyl monomer is absorbed into the seed particles in an aqueous medium, and the vinyl monomer is polymerized within the seed particles. Thereby, the seed particles can be grown, and polymer particles having a particle diameter larger than that of the original seed particles can be obtained. In particular, it is possible to seed-polymerize a vinyl-based monomer in the presence of seed particles and a surfactant in a liquid medium to obtain a crude product containing polymer particles containing the surfactant and the medium. preferable.
Among these polymerization methods, emulsion polymerization or seed polymerization is preferred, and seed polymerization is the most preferred, because the resulting polymer particles have the least variation in particle size.
A general method of seed polymerization will be described below, but the polymerization method in the production method of the present invention is not limited to this method.

First, an emulsion (suspension) containing an aqueous medium, a vinyl monomer, and a surfactant is prepared.
Here, the aqueous medium is water or a mixture of water and an organic solvent (for example, a lower alcohol having 5 or less carbon atoms). Further, the surfactant is a surfactant having an SP value of 9.0 to 12.0 and a polyoxyalkylene chain, and a surfactant having an SP value of 9.0 to 12.0 and having no polyoxyalkylene chain. Contains drugs.
The amount of surfactant to be used is preferably in the range of 0.01 to 5 parts by mass with respect to 100 parts by mass of the vinyl monomer.
A known method can be used to prepare the emulsion (suspension). For example, an emulsified liquid can be obtained by adding a vinyl-based monomer and a surfactant to an aqueous medium and dispersing the mixture with a fine emulsifier such as a homogenizer, an ultrasonic processor, or Nanomizer (registered trademark).
It is preferable that the particle size of the droplets of the vinyl-based monomer present in the obtained emulsion is smaller than the particle size of the seed particles to be added next, because the droplets are efficiently absorbed by the seed particles.

Next, seed particles are added to the resulting emulsion (suspension).
The seed particles may be added to the emulsion as they are, or may be added to the emulsion in the form of being dispersed in an aqueous medium. When the seed particles are added to the emulsion, the seed particles absorb the vinyl-based monomer. As a method for allowing the seed particles to absorb the vinyl-based monomer, a method of stirring the emulsified liquid at room temperature (about 20° C.) for 1 to 12 hours is usually mentioned. In addition, the emulsion may be heated to about 30 to 50° C. in order to promote the absorption of the vinyl-based monomer into the seed particles.

When the seed particles absorb the vinyl-based monomer, the seed particles swell. The mixing ratio of the vinyl monomer and the seed particles is preferably in the range of 5 to 300 parts by mass, more preferably 50 to 250 parts by mass, per 1 part by mass of the seed particles. More preferably within
If the mixing ratio of the vinyl-based monomer is smaller than the above range, the increase in particle size due to polymerization becomes small, resulting in a decrease in production efficiency. If the mixing ratio of the vinyl-based monomer exceeds the above range, the vinyl-based monomer will not be completely absorbed by the seed particles, and suspension polymerization will occur independently in the aqueous medium, resulting in an unintended and abnormal particle size. Polymer particles may be produced. The completion of the absorption of the vinyl-based monomer into the seed particles can be determined by confirming the enlargement of the particle size by observation with an optical microscope.
Polymer particles are then obtained by polymerizing the vinyl-based monomer absorbed in the seed particles. The polymer particles may be obtained by repeating the step of allowing the seed particles to absorb the vinyl-based monomer and polymerizing the same a plurality of times.

If necessary, a polymerization initiator may be used in the polymerization of the vinyl-based monomer. The polymerization initiator may be mixed in advance with the vinyl-based monomer and then dispersed in the aqueous medium, or both the polymerization initiator and the vinyl-based monomer may be separately dispersed in the aqueous medium.
The polymerization initiator to be used is not particularly limited. For example, benzoyl peroxide, lauroyl peroxide, o-chlorobenzoyl peroxide, o-methoxy benzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-ethylhexanoate, di -Organic peroxides such as tert-butyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2, 3-dimethylbutyronitrile), 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,3,3-trimethylbutyronitrile), 2,2'-azobis (2 -isopropylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), (2-carbamoylazo)isobuty One or more selected from the group consisting of azo compounds such as lonitrile, 4,4'-azobis(4-cyanovaleric acid), dimethyl-2,2'-azobisisobutyrate and the like. The polymerization initiator is preferably used within the range of 0.1 to 1.0 parts by mass with respect to 100 parts by mass of the vinyl monomer.

The polymerization temperature and polymerization time for seed polymerization can be appropriately selected according to the type of vinyl monomer and the type of polymerization initiator used as necessary. The polymerization temperature can be, for example, 25-110°C, preferably 50-100°C. Polymerization time can be, for example, 1 to 12 hours.
The polymerization reaction of seed polymerization may be carried out under an atmosphere of an inert gas (for example, nitrogen) that is inert to the polymerization.
In the production of the polymer particles of the present invention, the polymerization reaction of the seed polymerization can be carried out by raising the temperature after the vinyl-based monomer and optionally used polymerization initiator are completely absorbed by the seed particles. preferable.

In seed polymerization, a polymer dispersion stabilizer may be added to the polymerization reaction system in order to improve the dispersion stability of the polymer particles. Polymer dispersion stabilizers include, for example, polyvinyl alcohol, polycarboxylic acid, celluloses (hydroxyethyl cellulose, carboxymethyl cellulose, etc.), polyvinylpyrrolidone, and the like. Moreover, the polymer dispersion stabilizer may be used in combination with an inorganic water-soluble polymer compound such as sodium tripolyphosphate. Among these polymeric dispersion stabilizers, it is preferable to use polyvinyl alcohol and polyvinylpyrrolidone. The amount of polymer dispersion stabilizer to be added is preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the vinyl monomer.

Nitrite such as sodium nitrite, sulfites, hydroquinones, ascorbic acids, water-soluble vitamins are added to suppress the generation of emulsion polymerization products (polymer particles with too small particle size) in the aqueous medium during the polymerization reaction. A water-soluble polymerization inhibitor such as B group, citric acid, and polyphenols may be added to the aqueous medium. When a polymerization inhibitor is used, the amount added is preferably in the range of 0.02 to 0.2 parts by mass with respect to 100 parts by mass of the vinyl monomer.

The method for preparing seed particles used for seed polymerization is not particularly limited, and dispersion polymerization, emulsion polymerization, soap-free emulsion polymerization (emulsion polymerization that does not use a surfactant as an emulsifier), seed polymerization, suspension polymerization, etc. may be used. can be done.
In order to obtain polymer particles having substantially uniform particle diameters by seed polymerization, it is necessary to first use seed particles having substantially uniform particle diameters and grow these seed particles substantially uniformly.
Seed particles having a substantially uniform particle size, which is a raw material, can be obtained by subjecting a vinyl-based monomer to emulsion polymerization, dispersion polymerization, or the like. Emulsion polymerization, soap-free emulsion polymerization, seed polymerization and dispersion polymerization are preferably used.

A polymerization initiator is optionally used in the polymerization for obtaining seed particles. Examples of the polymerization initiator include polymerization initiators that can be used in the seed polymerization. The amount of the polymerization initiator to be used is preferably in the range of 0.1 to 3 parts by mass with respect to 100 parts by mass of the vinyl-based monomer used to obtain the seed particles. The weight average molecular weight of the resulting seed particles can be adjusted by adjusting the amount of the polymerization initiator used.

A molecular weight modifier may be used to adjust the weight average molecular weight of the seed particles during the polymerization of the seed particles. Examples of molecular weight modifiers include mercaptans such as n-octyl mercaptan and tert-dodecyl mercaptan, α-methylstyrene dimer; terpenes such as γ-terpinene and dipentene, and halogenated hydrocarbons such as chloroform and carbon tetrachloride. One or more selected from the group consisting of can be used. The weight average molecular weight of the obtained seed particles can be adjusted by adjusting the amount of the molecular weight modifier used.

<Solid-liquid separation step>
In the solid-liquid separation step when producing the polymer particles of the present invention, the crude product containing the surfactant-containing polymer particles obtained in the polymerization step and the medium is put into a filter, and the crude product is filtered. In this step, the medium contained in the crude product is passed through the filter medium of the filter to be removed, and the polymer particles contained in the crude product are held on the filter medium for solid-liquid separation.

In the solid-liquid separation step, the amount of medium passing through the filter medium per unit time is expressed by the following formula (3);
X≦5.50×A (3)
(In formula (3), X is the amount of medium passing through the filter medium per unit time (kg/min), and A is the interface area (m ² ) between the filter medium and the substance to be filtered.)
is preferably satisfied.
In the solid-liquid separation step, by controlling the amount of the medium passing through the filter medium per unit time so as to satisfy the above formula (3), the medium and by-products generated during the polymerization reaction (emulsion polymerization product ), surplus surfactants, polymer dispersion stabilizers used as needed, and additives such as polymerization inhibitors used as needed can be removed. This makes it possible to easily adjust (reduce) the amounts of the surfactant and non-volatile components contained in the polymer particles remaining on the filter medium.

The filter used in the solid-liquid separation step is not particularly limited. For example, using a pressurized filter comprising a pressure container having a cylindrical inner space, a filter material arranged in the inner bottom of the pressure container, and a compressed gas supply device for supplying compressed gas into the pressure container. can be done. In the pressure filter, the area of the bottom surface (filtering area) of the cylindrical internal space of the pressure vessel can be made substantially the same as the area of the interface between the filter medium and the material to be filtered (crude product).

The solid-liquid separation step using such a pressure filter includes, for example, the following method.
(a) Charge the crude product in the form of a slurry solution into the pressure vessel of the pressure filter.
(b) Load the crude product onto the filter media in a pressure vessel.
(c) The compressed gas supply device supplies compressed gas to the upper space of the filter medium inside the pressure vessel, and pressurizes the upper space of the filter medium inside the pressure vessel.
(d) By pressurizing the upper space, the crude product is pressed against the filter medium, the liquid medium contained in the crude product passes through the filter medium, and is discharged outside the pressure vessel as a filtrate, and the polymer is deposited on the filter medium. A cake of particles can be obtained.

The pressure-resistant container is preferably made of, for example, stainless steel and has a pressure resistance of 0.50 MPa or higher.
The filter medium is not particularly limited as long as it can reliably collect the polymer particles. For example, filter cloth such as woven fabric or non-woven fabric made of natural fiber, synthetic fiber, etc., wire mesh made of sintered metal, non-woven fabric made of sintered metal, filter plate (perforated plate) made of natural fiber, glass fiber, etc., synthetic One or more selected from the group consisting of resin nets, filter paper, glass fiber filters, etc., and filter cloth is particularly preferred.

In the solid-liquid separation step, the pressurization conditions when pressurizing the upper space of the filter medium in the pressure vessel using the pressurized filter are not particularly limited as long as the above formula (3) is satisfied. For example, it is preferable to apply pressure so that the internal pressure of the pressure vessel is within the range of 0.01 MPa to 0.50 MPa. In the solid-liquid separation step, the internal pressure of the pressure vessel is preferably kept substantially constant from the start of pressurization to the end of the solid-liquid separation step so as to satisfy the above formula (3). After pressurization, the internal pressure of the pressure vessel gradually decreases as the medium contained in the crude product passes through the filter medium. Specifically, when the amount of medium passing through the filter medium decreases or almost disappears, the compressed air pressure in the pressure vessel is released from the bottom, making it difficult to maintain the internal pressure of the pressure vessel at the pressurized pressure.

In the solid-liquid separation process, the amount of medium contained in the crude product put into the filter (pressure filter) (when all the crude products obtained in the polymerization process are put into the filter, the It is preferable to remove the medium contained in the crude product by performing until 70% by mass or more, preferably 75 to 85% by mass of the medium passes through the filter medium with respect to 100% by mass of the medium used). . As a result, by-products (emulsion polymerization products) generated during the polymerization reaction, surplus surfactants, polymer dispersion stabilizers used as necessary, polymerization inhibitors used as necessary, etc. Unnecessary components such as additives can be removed. This makes it possible to easily adjust (reduce) the amounts of the surfactant, non-volatile components and unnecessary components contained in the polymer particles remaining on the filter medium.
In the solid-liquid separation step, when the amount of medium passing through the filter medium (discharge amount) is less than 70% by mass with respect to 100% by mass of the amount of medium contained in the crude product, unnecessary components can be sufficiently removed. In some cases, it may be difficult to adjust (reduce) the amounts of the surfactant and non-volatile components contained in the polymer particles remaining on the filter medium.

In the solid-liquid separation step, when a pressure filter is used as a filter, the amount of medium is 70% by mass or more with respect to 100% by mass of the medium contained in the crude product introduced into the pressure filter. It is preferable that the process is terminated when the pressure has passed through the filter medium and the internal pressure of the pressure vessel has become 2/3 or less of the pressure at the time of pressurization. As a result, the residual amount of unnecessary components in the polymer particles remaining on the filter medium can be reliably reduced.

In the solid-liquid separation step, there is no particular limitation on the dewatering rate when removing the medium from the slurry composed of the crude product containing the polymer particles and the medium. For example, the range is 0.025 to 0.095 kg/min·m ² , preferably 0.025 to 0.08 kg/min·m ² , more preferably 0.028 to 0.075 kg/min·m ² . can.
If the dewatering speed is too fast, unnecessary components contained in the polymer particles may not be sufficiently removed, making it difficult to adjust (reduce) the amount of surfactant and non-volatile components contained in the polymer particles. may become.
If the dewatering rate is too slow, the solid-liquid separation step takes a long time, resulting in poor workability, and the surfactant contained in the polymer particles may be lost more than necessary.

<Washing process>
In the washing step for producing the polymer particles of the present invention, a washing solution is introduced into the filter holding the polymer particles on the filter medium after the solid-liquid separation step, and the polymer particles on the filter medium and the washing solution are separated from each other. and removing the washing liquid from the filter medium to obtain the washed polymer particles on the filter medium.
In the washing step, the present inventors have determined that the polymer particles (cake of polymer particles) on the filter medium obtained in the solid-liquid separation step are 10 times or less, preferably 1 to 9 times the volume of the polymer particles. After being immersed in a washing solution of 1.7 to 8 times more preferably 1.5 to 7 times more preferably 1.5 to 7 times, a washing treatment is performed, and if necessary, the polymer particles on the filter medium after washing are removed. , Again immersed in a cleaning solution of 10 times or less, preferably 1 to 9 times, more preferably 1.7 to 8 times, and still more preferably 1.5 to 7 times the volume of the polymer particles to perform cleaning treatment. We found a way to repeat the operation. They also found that the amount of surfactant present in the polymer particles can be controlled by immersing the polymer particle cake in the cleaning liquid.

For example, in the washing process, a pressurized filtration comprising a pressure vessel having a cylindrical inner space, a filter material arranged at the inner bottom of the pressure vessel, and a compressed gas supply device for supplying compressed gas into the pressure vessel When a vessel is used, the cake of polymer particles remaining on the filter medium is brought into contact with the washing liquid by feeding the washing liquid into the pressure vessel while the cake of polymer particles remains on the filtering medium. At this time, the cake is immersed in the cleaning liquid, and the cake is liquefied, so that cracks in the cake are self-repaired. This eliminates the short pass of the cleaning liquid, suppresses the amount of cleaning liquid used, and enables efficient cleaning.

Next, the compressed gas is supplied to the upper space of the filter medium in the pressure vessel by the compressed gas supply device to pressurize the upper space of the filter medium. As a result, the cake comes into contact with the washing liquid and is washed, and the washed washing liquid is discharged out of the pressure vessel as a filtrate.
In the washing step, after the washing liquid is introduced into the filter and brought into contact with the polymer particles, the washing liquid supplied into the filter and the cake are mixed with a stirrer to form a slurry before pressurization. may
Cracks in the cake may be repaired using a stirrer before supplying the cleaning liquid for cleaning. As a result, the short pass of the cleaning liquid is eliminated, and efficient cleaning can be performed.

In the washing step, there is no particular limitation on pressurization conditions when pressurizing the upper space of the filter medium in the pressure vessel using the pressurized filter. For example, it is preferable to apply pressure so that the internal pressure of the pressure vessel is in the range of 0.01 to 0.50 MPa. Moreover, the upper space of the filter medium is preferably pressurized at a rate of 0.01 to 0.30 MPa/min. In addition, in the washing process, it is preferable that the internal pressure of the pressure vessel is kept substantially constant from the start of pressurization to the end of the washing process. After pressurization, the internal pressure of the pressure-resistant container gradually decreases as the introduced washing liquid passes through the filtering material. Specifically, when the amount of washing liquid passing through the filter medium decreases or almost disappears, the compressed air pressure in the pressure vessel is released from the bottom, making it difficult to maintain the internal pressure of the pressure vessel at the pressurized pressure.

In the washing step, the amount of medium contained in the crude product put into the filter (pressure filter) (when all the crude product obtained in the polymerization step was put into the filter, It is preferable to remove the medium contained in the polymer particles until 70% by mass or more, preferably 90 to 97% by mass of the medium per 100% by mass of the medium passes through the filter medium. As a result, by-products (emulsion polymerization products) generated during the polymerization reaction, surplus surfactants, polymer dispersion stabilizers used as necessary, polymerization inhibitors used as necessary, etc. Unnecessary components such as additives can be removed. This makes it possible to easily adjust (reduce) the amount of surfactant and non-volatile components contained in the polymer particles remaining on the filter medium.
In the washing step, if the amount of medium passing through the filter medium (discharge amount) is less than 70% by mass with respect to 100% by mass of the amount of medium contained in the crude product, there is a possibility that unnecessary components cannot be sufficiently removed. It may be difficult to adjust (reduce) the amount of surfactant and non-volatile components contained in the polymer particles remaining on the filter medium.

In the washing step, when a pressure filter is used as the filter, 70% by mass or more of the medium is used as the filter material with respect to 100% by mass of the medium contained in the crude product put into the pressure filter. It is preferable to finish the process when the pressure has passed and the internal pressure of the pressure vessel has become 2/3 or less of the pressure at the time of pressurization. As a result, the residual amount of unnecessary components in the polymer particles remaining on the filter medium can be reliably reduced.

The washing liquid used in the washing step is preferably an aqueous medium, and examples thereof include water, lower alcohols having 5 or less carbon atoms such as methyl alcohol and ethyl alcohol, and mixtures thereof. In particular, it is preferable to use the same medium as used in the polymerization step.
The mass of the washing liquid used in the washing process is the mass of the polymer particles retained on the filter medium (when all the crude products obtained in the polymerization process in the solid-liquid separation process are put into the filter, It is preferably 10 times or less, preferably 1 to 9 times, more preferably 1.7 to 8 times, still more preferably 1.5 to 7 times the total amount of vinyl monomers used). In the present invention, by immersing the cake of polymer particles held on the filter medium in the washing liquid, the cake is liquefied and cracks in the cake are self-repaired. As a result, there is no short pass of the cleaning liquid, efficient cleaning can be performed, and there is no need to use a large amount of cleaning liquid. When the mass of the cleaning liquid used in the cleaning step is 10 times or less, it is possible to prevent the surfactant and non-volatile components from eluting more than necessary in the cleaning step, and the surfactant and The amount of non-volatile components can be easily controlled.

The mass of the washing liquid used in the washing process is adjusted to an appropriate amount in consideration of the type of each surfactant used in the polymerization process, thereby further reducing the content of each component adhering to the surface of the polymer particles. can be done. For example, if the amount of the washing liquid exceeds an appropriate amount, the surfactant having an SP value of 9.0 to 12.0 and having a polyoxyalkylene chain is gradually eluted, and the SP value contained in the polymer particles is reduced. 9.0 to 12.0 and the amount of surfactant having a polyoxyalkylene chain may not reach the predetermined amount.

In the washing step, the filtration rate for removing the washing liquid from the polymer particles is not particularly limited. For example, the range is 0.025 to 0.095 kg/min·m ² , preferably 0.025 to 0.08 kg/min·m ² , more preferably 0.028 to 0.075 kg/min·m ² . can.
If the dewatering speed is too fast, unnecessary components contained in the polymer particles may not be sufficiently removed, making it difficult to adjust (reduce) the amount of surfactant and non-volatile components contained in the polymer particles. may become.
If the dewatering rate is too slow, the solid-liquid separation step takes a long time, resulting in poor workability, and the surfactant contained in the polymer particles may be lost more than necessary.

The temperature of the washing liquid used for washing is a temperature at which the surfactant used in the polymerization is sufficiently eluted, for example, 40 to 80°C, preferably 50 to 80°C. As a method of washing by heating the cleaning liquid to a certain temperature, a method of supplying the heated cleaning liquid to the filter may be used. A method of heating the cleaning liquid may also be used.

In the washing process, the conductivity of the washing liquid that has passed through the filter medium is 2.0 times or less than the conductivity of the washing liquid before being put into the filter (pressure filter), and the internal pressure of the pressure container is pressurized. It is preferable to terminate when the pressure becomes 2/3 or less of the pressure.
By performing washing until the conductivity of the washing liquid that has passed through the filter medium is reduced to 2.0 times or less, the residual amount of unnecessary components contained in the finally obtained polymer particles can be reliably reduced. In addition, by washing until the internal pressure of the pressure container is 2/3 or less of the pressure at pressurization, the amount of water that can be absorbed by the polymer particles can be reduced, and the polymer particles can be dried after washing. The time required can be shortened.

<Drying process and classification process>
The polymer particles obtained in the washing step are preferably dried with a known dryer to remove the washing liquid. Although the dryer is not particularly limited, it is preferable to use a vacuum dryer, for example, a vacuum stirring dryer (crushing dryer) incorporating stirring blades. The washing liquid is almost completely removed by drying, and if necessary, classification (preferably, airflow classification) is performed to obtain polymer particles that can be used as a product.

The drying conditions in the present invention are appropriately adjusted according to the capacity and performance of the dryer to be used. For example, the following conditions can be adopted.
The degree of vacuum (vs. atmospheric pressure) can be, for example, in the range of -0.001 to -0.5 MPa, preferably -0.05 to -0.1 MPa.
The drying temperature can range, for example, from 40 to 80°C, preferably from 50 to 70°C.
The drying time can be, for example, 4 to 10 hours (hr), preferably 7 to 9 hours.
The operating conditions of the dryer used can be such that the agitation shear coefficient calculated by the following formula (4) is in the range of 1,800 to 2,800, preferably 1,900 to 2,800, and more preferably 1,950 to 2,750.
Stirring shear factor = [total area of stirring blades (m ² ) × number of revolutions (rpm) × time (hr)]/[weight of polymer particles (kg) × bulk specific gravity of polymer particles (unitless)] (4)
(Measurement of bulk specific gravity is based on JIS Z 8807: 2012)
If the value of the agitation shear coefficient is greater than 2800, the agitation force acting on the resin becomes excessive, and the particles may break.
If the value of the agitation shear coefficient is less than 1800, the agitation force acting on the resin will be too small, and the separation of the non-volatile component from the particles by shearing will be insufficient, and there is a risk that the remaining amount will be more than necessary.
The amount of polymer particles to be put into the dryer can be in the range of 0.1 to 1000 kg, preferably 0.5 to 500 kg.

In the present invention, in the drying step, the surfactant is eluted from the surface of the polymer particles into water, and then a crushing dryer is used to scrape off the non-volatile components together with water from the particle surface by the action of stirring shear. , can be fractionated by aspiration. This makes it possible to adjust the content of the surfactant per unit surface area of the polymer particles and the surface residual amount of the non-volatile components in the polymer particles.

By prewarming the cake after washing, it becomes possible to easily adjust the surfactant on the surface of the particles to a specified amount. In addition, the crushing drying process shears the non-volatile components, resulting in most fractionation. Then, the surface of the polymer particles is effectively modified with the surfactant, and polymer particles with excellent dispersion uniformity and improved dispersibility can be obtained.

According to such a method for producing polymer particles, it is possible to remove an appropriate amount of the surfactant adhering to the polymer particles in the polymerization step together with the medium and the washing liquid. Furthermore, a surfactant having an SP value of 9.0 to 12.0 and a polyoxyalkylene chain, a surfactant having an SP value of 9.0 to 12.0 and not having a polyoxyalkylene chain, and other surfactants When polymerization of vinyl monomers is carried out in the presence of surfactants containing active agents, most of the other surfactants can be sufficiently removed together with the medium and washing liquid. As a result, the SP value per unit surface area of the polymer particles is 9.0 to 12.0 and the surfactant having a polyoxyalkylene chain and the SP value being 9.0 to 12.0 and having a polyoxyalkylene chain The content (residual amount) of surfactants not having the can also be adjusted appropriately.

[Use of polymer particles]
The polymer particles of the present invention can be used for various purposes. For example, it can be used as an optical member, an additive for paints, and an anti-blocking agent.
For example, a resin composition containing polymer particles and a resin binder is formed and used to obtain an optical film such as an antiglare film or a light diffusion film or an optical member such as a light diffuser, particularly an antiglare member. be able to.
For example, a paint can be obtained as the polymer particles themselves or as a mixture thereof with binder resins, additives and the like.
For example, a resin molded product can be obtained by molding the polymer particles themselves or a mixture of the same and a resin.
For example, the polymer particles themselves can be mixed with a resin as an antiblocking agent to form a resin composition, and a resin molding such as a film can be formed.

[Resin composition]
The resin composition of the present invention contains the polymer particles of the present invention and a resin binder.

<Binder>
The binder is not particularly limited and may be appropriately selected according to the required properties such as transparency, dispersibility of polymer particles, light resistance, moisture resistance and heat resistance.
For example, (meth) acrylic resin, (meth) acrylic-urethane resin, urethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, melamine resin, styrene resin, alkyd resin, phenol resin, silicone resins such as epoxy resins, polyester resins, and polysiloxane resins; modified silicone resins such as (meth)acryl-silicone resins, silicone-alkyd resins, silicone-urethane resins, and silicone-polyester resins; One or more resin binders selected from the group consisting of fluorine-based resins such as polyvinylidene fluoride and fluoroolefin vinyl ether polymers may be used.

From the viewpoint of improving the durability of the resin composition, the resin binder is preferably a curable resin capable of forming a crosslinked structure through a crosslinking reaction. Curable resins can be cured under various curing conditions, and include thermosetting resins, photo-curing resins, ultraviolet-curing resins, ionizing radiation-curing resins such as electron beam-curing resins, and temperature-curing resins. can be used.
As the thermosetting resin, one or more selected from the group consisting of thermosetting urethane resins composed of acrylic polyol and isocyanate prepolymer, phenol resins, urea melamine resins, epoxy resins, unsaturated polyester resins, silicone resins, etc. is given.

As the ionizing radiation curable resin, a polyfunctional (meth)acrylate resin such as a polyhydric alcohol polyfunctional (meth)acrylate; 1 or more selected from the group consisting of polyfunctional urethane acrylate resins such as those described above.
The ionizing radiation-curable resin preferably contains a polyfunctional (meth)acrylate resin, and more preferably contains a polyhydric alcohol polyfunctional (meth)acrylate having 3 or more (meth)acryloyl groups in one molecule. preferable. Polyhydric alcohol polyfunctional (meth)acrylates having 3 or more (meth)acryloyl groups in one molecule include, for example, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, 1,2 , 4-cyclohexane tri(meth)acrylate, pentaglycerol triacrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol tetra(meth) One or more selected from the group consisting of acrylates, dipentaerythritol hexa(meth)acrylate, tripentaerythritol triacrylate, tripentaerythritol hexaacrylate, and the like.

In addition to these, the ionizing radiation-curable resin is selected from the group consisting of polyether resins, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, etc., having acrylate-based functional groups. can also be used.
The resin binder may contain a thermoplastic resin in addition to the curable resin. Examples of thermoplastic resins include cellulose derivatives such as acetylcellulose, nitrocellulose, acetylbutylcellulose, ethylcellulose and methylcellulose, vinyl acetate homopolymers and copolymers, vinyl chloride homopolymers and copolymers, and vinylidene chloride homopolymers. Vinyl resins such as polymers and copolymers, acetal resins such as polyvinyl formal and polyvinyl butyral, homopolymers and copolymers of acrylic acid esters, homopolymers and copolymers of methacrylic acid esters (meth) At least one selected from the group consisting of acrylic resins, polystyrene resins, polyamide resins, linear polyester resins, polycarbonate resins and the like can be used.

As the resin binder, a rubber binder such as synthetic rubber or natural rubber, an inorganic binder, or the like can also be used. Examples of the rubber binder resin include one or more selected from the group consisting of ethylene-propylene copolymer rubber, polybutadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, and the like.
Examples of the inorganic binder include one or more selected from the group consisting of silica sol, alkali silicate, silicon alkoxide, phosphate, and the like. As the inorganic binder, an inorganic or organic-inorganic composite matrix obtained by hydrolyzing and dehydrating condensation of metal alkoxide or silicon alkoxide can also be used. As the inorganic or organic-inorganic composite matrix, a silicon oxide matrix obtained by hydrolyzing and dehydrating condensation of silicon alkoxide such as tetraethoxysilane can be used.

The amount of the polymer particles in the resin composition is 2 parts by mass or more, preferably 4 parts by mass or more, more preferably 6 parts by mass or more based on 100 parts by mass of the solid content of the resin binder.
By setting the amount of the polymer particles to 2 parts by mass or more, the layer (coating film) formed from the resin composition can sufficiently exhibit optical properties such as matte properties. As a result, optical properties such as anti-glare properties and light diffusing properties of the optical member obtained by coating the resin composition on the base material can be made sufficient.
The amount of the polymer particles in the resin composition is 300 parts by mass or less, preferably 200 parts by mass or less, more preferably 100 parts by mass or less based on 100 parts by mass of the solid content of the binder. When the amount is 300 parts by mass or less, it becomes easy to obtain sufficient linear permeability of the coating film formed from the coating resin composition.

When a photocurable resin or an ultraviolet curable resin is used among the ionizing radiation curable resins, a photopolymerization initiator can be added to the resin binder.
Any photopolymerization initiator may be used, but it is preferable to use one suitable for the photocurable resin or ultraviolet curable resin to be used.
Examples of photopolymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, α-hydroxyalkylphenones, α-aminoalkylphenones, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfoniums, onium salts, borate salts, active halogen compounds, α-acyloxime esters, etc. can be used.
The amount of the photopolymerization initiator used is usually within the range of 0.5 to 20% by mass, preferably within the range of 1 to 5% by mass, based on 100% by mass of the binder.

The resin composition may contain an organic solvent, if necessary. In particular, when the resin composition is applied onto a base material, the coating can be easily performed by containing an organic solvent. Examples of organic solvents include aromatic solvents such as toluene and xylene; alcohol solvents such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol and propylene glycol monomethyl ether; ester solvents such as ethyl and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone and cyclohexanone; 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, ethylene glycol dimethyl ether, ethylene glycol Glycol ethers such as diethyl ether, diethylene glycol dimethyl ether, propylene glycol methyl ether, 2-methoxyethyl acetate, 2-ethoxyethyl acetate (ethyl cellosolve acetate), 2-butoxyethyl acetate, propylene glycol methyl ether acetate, etc. Chlorine solvents such as chloroform, dichloromethane, trichloromethane, and methylene chloride, ether solvents such as tetrahydrofuran, diethyl ether, 1,4-dioxane, and 1,3-dioxolane, N-methylpyrrolidone, dimethylformamide , dimethylsulfoxide, and dimethylacetamide.

In the resin composition of the present invention, the dispersibility (compatibility) of the polymer particles is correlated with the viscosity value.
In the polymer particles of the present invention, the content of a surfactant having a polyoxyalkylene chain with an SP value of 9.0 to 12.0 is 1.0×10 ⁻³ to 6.0 per unit surface area of the polymer particles. ×10 ⁻³ g/m ² and the amount of the surfactant having no polyoxyalkylene chain with an SP value of 9.0 to 12.0 is 5.0×10 ⁻⁵ to 13.0×10 ⁻⁵ g /m ² , and the surface residue amount of non-volatile components is 2.0×10 ⁻³ g/m ² or less.
For this reason, when measuring the change in viscosity over time using an ultra-trace sample viscometer ("m-VROC" manufactured by Leosence), the dispersibility in the resin composition is
(1) As the particles become more familiar with the solvent, the particles are uniformly dispersed, the viscosity value increases, and the maximum peak (A value) is reached at a certain time.
(2) As the familiarity stabilizes, the dispersion area narrows again and the viscosity value decreases.
(3) the viscosity stabilizes at a certain stable value (B value) after a certain period of time;
A series of viscosity changes appear over time, resulting in excellent dispersion stability in the resin composition.
In the present invention, the maximum peak value of viscosity (value A), the stable value of viscosity (value B), and the time h (hr) until the viscosity stabilizes are expressed by the following formulas (5) and (6).
A×0.1≦B≦A×0.5 (5)
h<12 (6)
When both are satisfied, the dispersion stability in the resin composition is good, and when the resin composition is coated to produce an optical member, it has been found to exhibit uniform optical properties (excellent dispersion uniformity). did.
In formula (5), when the B value is smaller than the appropriate range, the viscosity is low and aggregates, and when the B value is greater than the appropriate range, the viscosity is too high and the surfactant aggregates to slow down the movement of the particles. It is thought that

The above A value, B value and h were specifically obtained by the following measurement methods.
-Used equipment-
Ultra-trace sample viscometer ("m-VROC" manufactured by Leosence)
-procedure-
(i) Put 0.50 g of polymer particles into a 50 cc sample bottle and add 5.0 g of toluene. After that, it is dispersed for 5 minutes using an ultrasonic cleaner.
(ii) 0.3 g of an acrylic resin (manufactured by DIC, "Acrydic (registered trademark) A-814") is added, and then dispersed for 5 minutes using an ultrasonic cleaner to prepare a sample.
(iii) Measure the viscosity of the prepared sample at 10 minute intervals until the rate of change in viscosity is less than 3%.
Let the maximum peak value be A value among the measured viscosities.
The viscosity value (stable value) when the rate of change in viscosity is less than 3% and the viscosity is stabilized is defined as the B value.
Let h be the time until the viscosity stabilizes.

[Optical member]
The optical member of the present invention has a layer of the resin composition on a substrate.
In the present invention, a layer of the resin composition can be formed by applying the resin composition containing the polymer particles of the present invention and a resin binder onto a substrate.
Examples of the optical member include a light diffusion film or an antiglare film for light diffusion or antiglare.

The substrate is preferably transparent. Examples of transparent substrates include glass, polyester polymers such as polyethylene terephthalate (PET) and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose (TAC), polycarbonate polymers, polymethyl cellulose, and the like. (Meth)acrylic polymers such as methacrylates, styrene polymers such as polystyrene and acrylonitrile/styrene copolymers, polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and olefin polymers such as ethylene/propylene copolymers , vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamides, polyimide-based polymers, polysulfone-based polymers, polyethersulfone-based polymers, polyetheretherketone-based polymers, polyphenylsulfide-based polymers coalescence, vinyl alcohol-based polymer, vinylidene chloride-based polymer, vinyl butyral-based polymer, arylate-based polymer, polyoxymethylene-based polymer, epoxy-based polymer, mixture containing at least one or more of these polymers, A laminate or the like of these polymers can be used as a substrate. Among these, those having a particularly low birefringence are preferably used.
Furthermore, on at least one surface of these substrates, an easy-adhesion layer such as (meth)acrylic resin, copolymerized polyester resin, polyurethane resin, styrene-maleic acid grafted polyester resin, acrylic grafted polyester resin, etc. The provided material can be used as a base material.
The thickness of the base material can be determined as appropriate, but is generally within the range of 10 to 500 μm from the viewpoints of strength, workability such as handling, and thinness. It is preferably 20 to 300 μm, more preferably 30 to 200 μm.
The substrate may contain additives. Examples of additives include ultraviolet absorbers, infrared absorbers, antistatic agents, refractive index modifiers, enhancers, and the like.
The method of applying the resin composition onto the substrate is not particularly limited. For example, known coating methods such as bar coating, blade coating, spin coating, reverse coating, die coating, spray coating, roll coating, gravure coating, micro gravure coating, lip coating, air knife coating, and dip coating can be used. can.

When the resin binder contained in the resin composition has ionizing radiation curability, the resin composition is applied, and after forming a layer of the resin composition on the substrate, it is irradiated with an active energy ray and dried. Can be cured.
Examples of active energy rays include ultraviolet rays and infrared rays emitted from light sources such as LEDs, xenon lamps, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, carbon arc lamps, and tungsten lamps, and Cockcroft-Walton of usually 20 to 2000 KeV. electron beams, α-rays, β-rays, γ-rays, etc. extracted from electron beam accelerators such as type, Van de Graaff type, resonance transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type accelerators can be used.
The thickness (dry thickness) of the layer of the resin composition is not particularly limited, and is appropriately determined according to the particle size of the polymer particles. For example, it can be 1-10 μm, preferably 3-7 μm.

[Resin molding]
The polymer particles of the present invention can be used alone or mixed with other resins to prepare resin moldings by various molding methods. As the other resin, a transparent resin can be preferably used, and the polymer particles can function as light diffusion particles in the resin molding.
The resin molded body functions as a light diffuser such as a light diffusion plate, and can be used as an LED lighting cover or the like.

Examples of transparent resins include (meth)acrylic resins, polycarbonate resins, polystyrene resins, (meth)acrylic-styrene resins (copolymers of (meth)acrylic acid esters and styrene), and the like. More than one type can be used. Among them, polystyrene resins or (meth)acrylic-styrene resins are preferred.

When preparing a resin molded article from the polymer particles of the present invention and a transparent resin, the amount of the polymer particles contained in the resin molded article is in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of the transparent resin. Preferably, it can be in the range of 0.1 to 5 parts by mass. The resin molding may contain additives such as ultraviolet absorbers, antioxidants, heat stabilizers, light stabilizers, and fluorescent brighteners, if necessary.
The thickness, shape, etc. of the resin molding can be appropriately selected depending on the application.

The resin molding can be obtained by melt-kneading the transparent resin and the polymer particles using a single-screw extruder, a twin-screw extruder, or the like. Alternatively, the resin composition obtained by melt-kneading may be molded into a plate shape through a T-die and a roll unit to obtain a resin molding. Furthermore, the resin composition obtained by melt-kneading may be pelletized, and the pellets may be molded by injection molding, press molding, or the like to obtain a resin molding.
The resin molded article containing the polymer particles of the present invention is excellent in the uniformity of dispersion of the polymer particles, and exhibits optical properties such as uniform light diffusion and anti-glare properties.

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Unless otherwise specified, "%" means "% by mass" and "parts" means parts by mass.
Various measurement methods in Examples and Comparative Examples are as follows.

[Volume average particle diameter of polymer particles and standard deviation of particle size distribution]
The volume average particle diameter and the standard deviation of the particle size distribution of the polymer particles are calibrated using Coulter Multisizer (TM) 3 (manufactured by Beckman Coulter, Inc.) according to the Multisizer (TM) 3 User's Manual published by Beckman Coulter, Inc. measured using an aperture.
Incidentally, the aperture used for the measurement is appropriately selected according to the size of the polymer particles to be measured. Current (aperture current) and Gain are appropriately set according to the size of the selected aperture. For example, if an aperture with a size of 50 μm is selected, Current (aperture current) is set to −800 and Gain is set to 4.

As a sample for measurement, 0.1 g of polymer particles was added to 10 ml of a 0.1% by mass nonionic surfactant aqueous solution, a touch mixer (manufactured by Yamato Scientific Co., Ltd., "TOUCHMIXER MT-31") and an ultrasonic cleaner ( A dispersion liquid obtained by dispersing using "ULTRASONIC CLEANER VS-150" manufactured by Vervoclear Co., Ltd. is used.
During the measurement, the inside of the beaker is gently stirred to the extent that air bubbles do not enter, and the measurement is terminated when 100,000 polymer particles are measured.
The volume average particle diameter of the polymer particles is the arithmetic mean of the volume-based particle size distribution of 100,000 particles.

[Coefficient of variation of particle size (CV value)]
The coefficient of variation (CV value) of the particle size of the polymer particles is calculated by the following formula.
Variation coefficient (CV value) of particle size of polymer particles = (standard deviation of volume-based particle size distribution of polymer particles/volume average particle size of polymer particles) x 100

[Volume average particle diameter of seed particles]
The volume average particle diameter of the seed particles used in the production of the polymer particles is measured using a laser diffraction/scattering particle size distribution analyzer ("LS 13 320" manufactured by Beckman Coulter, Inc.) and a universal liquid sample module.
As a measurement sample, 0.1 g of a slurry containing seed particles was added to 10 ml of a 0.1% by mass nonionic surfactant aqueous solution using a touch mixer (manufactured by Yamato Scientific Co., Ltd., "TOUCHMIXER MT-31") and ultrasonic cleaning. A dispersion liquid obtained by dispersing using a device (“ULTRASONIC CLEANER VS-150” manufactured by Vervoclear Co., Ltd.) is used.

The measurement was performed with the seed particles dispersed by pump circulation in the universal liquid sample module and with the ultrasonic unit (ULM ULTRASONIC MODULE) activated, and the volume average particle diameter of the seed particles ( Arithmetic mean diameter in volume-based particle size distribution) is calculated. Measurement conditions are shown below.

Medium: Water Refractive index of medium: 1.333
Refractive index of solid: refractive index of seed particles PIDS relative concentration: about 40-55%

[Content of surfactant in polymer particles]
The surfactant content in the polymer particles is measured by extracting the polymer particles with a solvent and using a liquid chromatograph mass spectrometer (LC/MS/MS device).
As the LC/MS/MS apparatus, "UHPLC ACCELA" manufactured by Thermo Fisher Scientific and "Linear Ion Trap LC/MSn LXQ" manufactured by Thermo Fisher Scientific were used.

In the polymer particles of Examples 1 to 17 and Comparative Examples 1 to 10, as a surfactant,
a: POEPS: Phosphanol LO-529 (manufactured by Toho Chemical Industry Co., Ltd.)
→ Sodium polyoxyethylene nonylphenyl ether phosphate b: POSPS: Plysurf AL (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
→ Polyoxyethylene styrenated phenyl ether phosphate c: POELE: Plysurf A210G (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
→ Polyoxyethylene lauryl ether phosphate d: POEAS: Plysurf A208F (Daiichi Kogyo Seiyaku Co., Ltd.)
→ Polyoxyethylene alkyl ether phosphate e: POEKG: Polyoxyethylene glyceryl caprylate f: POERS: Sodium polyoxyethylene lauryl ether phosphate g: POESM: Polyoxyethylene sorbitan monostearate i: DSS: Rapisol A-80 (Japan manufactured by Yusha)
→ Di(2-ethylhexyl) sodium sulfosuccinate
ii: ASK: sodium alkenyl succinate
iii: RSN: sodium lauryl sulfate
At least one of iv: PAI: isopropyl palmitate v: TOS: sorbitan trioleate was used, and the surfactant content in the polymer particles of Examples and Comparative Examples was measured by the method shown below. did.

About 0.10 g of polymer particles as a sample is precisely weighed into a centrifugal tube, 5 ml of methyl alcohol as an extract is added with a whole pipette, and the polymer particles and the extract are thoroughly mixed. After performing ultrasonic extraction for 15 minutes at room temperature, centrifugation is performed for 15 minutes at 3500 rpm, and the resulting supernatant is used as the test solution.

The surfactant concentration in this test solution is measured using an LC/MS/MS device. Then, the measured surfactant concentration (μg / ml) in the test solution, the mass of the polymer particles used as a sample (sample mass (g)), and the amount of extract (extract amount (ml)) , the surfactant content (μg/g) in the polymer particles is obtained from the following formula. In addition, the extract volume is 5 ml.

Surfactant content (μg/g)
= {Surfactant concentration in test solution (μg/ml) × amount of extract (ml)} ÷ sample mass (g)
The surfactant concentration is calculated from a calibration curve prepared in advance from peak area values on the obtained chromatogram using an LC/MS/MS device. Further, when the polymer particles contain multiple types of surfactants, a calibration curve is prepared for each of these surfactants, the concentration of the surfactant is calculated from the prepared calibration curve, and each calculated The content of the surfactant in the polymer particles is determined by taking the sum of the surfactant concentrations of the surfactants as the "surfactant concentration (μg/ml) in the test solution" in the above formula.

The method for preparing the calibration curve is as follows.
<Calibration curve of surfactant having polyoxyethylene chain>
For example, in the case of polyoxyethylene nonylphenyl ether phosphate, after preparing an intermediate standard solution (methyl alcohol solution) of about 1000 ppm of polyoxyethylene nonyl phenyl ether phosphate, further dilute it stepwise with methyl alcohol to 0.1 ppm. , 0.5 ppm, 1.0 ppm, 2.0 ppm, and 10.0 ppm are prepared as standard solutions for creating a calibration curve. The standard solution for creating a calibration curve at each concentration was measured under the LC measurement conditions and MS measurement conditions described later, and the monitor ion m / z = 502.3 (precursor ion) → 485.2 (product ion) on the chromatogram Obtain the peak area value. By plotting each concentration and area value, an approximate curve (quadratic curve) is obtained by the method of least squares, and this is used as a calibration curve for quantification.
Calibration curves for surfactants with other polyoxyethylene chains were similarly prepared.

<Calibration curve of surfactant without polyoxyethylene chain>
For example, in the case of di(2-ethylhexyl) sulfosuccinic acid, after preparing an intermediate standard solution (methyl alcohol solution) of about 1000 ppm of di(2-ethylhexyl) sulfosuccinate, further dilute it stepwise with methyl alcohol to 0.1 ppm. , 0.2 ppm, 0.5 ppm, 1.0 ppm, and 2.0 ppm are prepared as standard solutions for creating a calibration curve. The standard solution for creating a calibration curve at each concentration was measured under the LC measurement conditions and MS measurement conditions described later, and the monitor ion m / z = 421.3 (precursor ion) → 227.2 (product ion) on the chromatogram Obtain the peak area value. By plotting each concentration and area value, an approximate curve (quadratic curve) is obtained by the method of least squares, and this is used as a calibration curve for quantification.
A calibration curve for surfactants without other polyoxyethylene chains was also prepared in the same manner.

<LC measurement conditions>
Measuring device: UHPLC ACCELA (manufactured by Thermo Fisher Scientific)
Column: Hypersil GOLD C18 1.9 μm (inner diameter 2.1 mm, length 100 mm) (manufactured by Thermo Fisher Scientific)

<MS measurement conditions>
Measuring device: Linear Ion Trap LC/MSn LXQ (manufactured by Thermo Fisher Scientific)
Ionization: (ESI/negative)
Sheath Gas: 30arb
Auxiliary gas (AUX Gas): 10arb
Sweep Gas: 0arb
Spray voltage (I Spray Voltage): 5.0 kV
Capillary Temp: 350°C
Capillary Voltage: -20V
Tube lens Voltage: -100V
Monitoring ion (m/Z): 200-2000

(Surfactant with polyoxyethylene chain)
For example, in the case of polyoxyethylene nonylphenyl ether phosphate, it can be calculated from monitor ions as (n=502.3/n2=485.2).
Surfactants with other polyoxyethylene chains were calculated similarly.

(Surfactant without polyoxyethylene chain)
For example, in the case of di(2-ethylhexyl)sulfosuccinic acid, it can be calculated from monitor ions as (n=421.3/n2=227.2).
Other surfactants without polyoxyethylene chains were calculated similarly.

[Specific surface area of polymer particles]
The specific surface area of the polymer particles was measured by the BET method (nitrogen adsorption method) described in ISO 9277 1st edition JIS Z 8830:2001.
For the target polymer particles, the BET nitrogen adsorption isotherm is measured using an automatic specific surface area/pore size distribution measuring device (manufactured by Shimadzu Corporation, "Tristar 3000"), and the BET multipoint method is used from the amount of nitrogen adsorption. to calculate the specific surface area.
The measurement was performed using nitrogen as an adsorbate after pretreatment by hot gas purging, and a constant volume method was used under the conditions of an adsorbate cross-sectional area of 0.162 nm ² . In the pretreatment, specifically, while heating the container containing the polymer particles at 65° C., nitrogen purge is performed for 20 minutes, and after cooling to room temperature, the container is heated at 65° C. Vacuum degassing was carried out until the pressure in the container became 0.05 mmHg or less.

[Content of surfactant (per unit surface area of polymer particles)]
Using the surfactant content in the polymer particles obtained above and the specific surface area of the polymer particles obtained above, the surfactant content per unit surface area of the polymer particles is calculated by the following formula. amount was calculated.
Surfactant content per unit surface area of polymer particles (g/m ² ) = (content of surfactant in polymer particles (g/1 g of polymer particles)/specific surface area of polymer particles (m ² /g)

[Surface residual amount of non-volatile components (per unit surface area of polymer particles)]
<Quantification of non-volatile components>
When the polymer particles are dispersed in water and centrifuged, the polymer particles having the desired particle size settle, while the by-product (emulsion polymerization product) contained in the polymer particles floats to a small amount. of water constitutes the supernatant liquid. Therefore, here, the content of the by-product (emulsion polymerization product) in the polymer particles is measured as the content of the non-volatile component in the supernatant.

(Preparation of supernatant liquid)
5.0 g of the polymer particles obtained in each example and each comparative example are placed in a sample bottle having a capacity of 50 ml, and 15.0 g of water is added. Thereafter, dispersion treatment is performed for 60 minutes using an ultrasonic cleaner (“ULTRASONIC CLEANER VS-150” manufactured by Vervoclear Co., Ltd., oscillation frequency: 50 Hz, high frequency output: 150 W) to disperse the polymer particles in water. to obtain a dispersion. If the polymer particles are difficult to disperse in water, the polymer particles may be moistened with a trace amount (upper limit of 0.8 g) of alcohol (for example, ethyl alcohol) and then dispersed in water.
Next, 20.0 g of the dispersion is placed in a centrifuge tube with an inner diameter of 24 mm, for example, a centrifuge tube with an inner capacity of 50 ml and an inner diameter of 24 mm (manufactured by Thermo Fisher Scientific, product name “Nalgene (registered trademark) 3119-0050”). The centrifuge tube is set in a rotor, such as an angle rotor (model number “RR24A”, manufactured by Hitachi Koki Co., Ltd., in which eight centrifuge tubes with a content of 50 ml are set), and centrifuged, such as a high-speed cooling centrifuge (high -Speed refrigerated centrifuge) (model number "CR22GII", manufactured by Hitachi Koki Co., Ltd.), and set the rotor to K factor 6943 using the high-speed cooling centrifuge (when the angle rotor is used, the rotation speed is 4800 rpm Sometimes the K factor becomes 6943), the supernatant is collected after centrifugation under the conditions of rotation time of 30 minutes.

(Quantification of by-products)
The content of by-products contained in 5.0 g of the recovered supernatant was determined as follows.
5.0 g of the supernatant liquid is weighed into a 10 ml sample bottle whose mass has been weighed in advance, and placed in a vacuum oven at a temperature of 60° C. for 5 hours to evaporate water. Weigh the mass (g) of the sample bottle containing the evaporated to dryness residue, i.e. the non-volatile components.
From the mass (g) of the sample bottle containing non-volatile components, the mass (g) of the sample bottle, and the mass (g) of the supernatant liquid in the sample bottle (= 5.0 g), the supernatant is The concentration (% by mass) of non-volatile components (corresponding to by-products (emulsion polymerization products)) in the liquid was calculated.
(Concentration of non-volatile components in supernatant liquid) (% by mass) = {(mass of sample bottle containing non-volatile components) (g) - (mass of sample bottle) (g)} ÷ (supernatant in sample bottle Mass of liquid) (g) x 100

<Calculation of surface residue amount of non-volatile components (per unit surface area of polymer particles)>
Using the content of the non-volatile components in the polymer particles obtained above and the specific surface area of the polymer particles, the surface residual amount of the non-volatile components per unit surface area of the polymer particles is calculated by the following formula. did.
Surface residue amount of non-volatile components per unit surface area of polymer particles (g/m ² ) = (content of non-volatile components in polymer particles (g/1 g of polymer particles)/specific surface area of polymer particles ( ^m2 /g)

[Gel fraction of polymer particles]
The gel fraction of polymer particles indicates the degree of cross-linking of polymer particles, and is measured by the following method.
1.0 g of polymer particles as a sample and 0.03 g of boiling stone were precisely weighed and charged into a 200 ml eggplant flask, and 100 ml of toluene was added. The eggplant flask is immersed in an oil bath kept at ℃ and refluxed for 24 hours.
After refluxing, the content (dissolution liquid) in the eggplant flask was weighed by attaching glass fiber filters "GB-140 (φ37 mm)" and "GA-200 (φ37 mm)" manufactured by ADVANTEC. Filtration is performed using a Buchner funnel type filter 3G (glass particle pore diameter 20 to 30 μm, volume 30 mL), and the solid content is collected in the Buchner funnel type filter 3G. Then, the solid content collected in the Buchner funnel filter 3G is dried together with the Buchner funnel filter 3G in a vacuum oven at 130° C. for 1 hour, and then dried at a gauge pressure of 0.06 MPa for 2 hours to obtain toluene. Remove and cool to room temperature.
After cooling, the total mass of the Buchner funnel filter 3G, the glass fiber filter and the solid content is measured with the solid content contained in the Buchner funnel filter 3G. Then, the mass (g) of the dry powder is obtained by subtracting the mass of the Buchner funnel filter 3G and the glass fiber filter and the mass of the boiling stone from the measured total mass.
Using the mass (g) of the dry powder and the mass (g) of the sample put into the round-bottomed flask, the gel fraction is calculated by the following formula.
Gel fraction (% by mass) = {dry powder (g) / sample mass (g)} x 100

[viscosity]
(i) Put 0.50 g of polymer particles into a 50 cc sample bottle and add 5.0 g of toluene. After that, it is dispersed for 5 minutes using an ultrasonic cleaner.
(ii) 0.3 g of an acrylic resin (manufactured by DIC, "Acrydic (registered trademark) A-814") is added, and then dispersed for 5 minutes using an ultrasonic cleaner.
(iii) The viscosity is measured with an ultra-trace sample viscometer ("m-VROC" manufactured by Leosence) at intervals of 10 minutes until the rate of change in viscosity is less than 3%. In the measurement of each elapsed time, evaluation was performed after 1 minute dispersion with ultrasonic waves and after standing for 10 minutes.

[Dispersibility]
(i) 0.1 g of polymer particles and 5 g of toluene are weighed in a plastic pot "A-4 (30)", and a defoaming stirrer (Thinky Corporation, rotation / revolution mixer (atmospheric pressure type) AR-100 (Product name: Thinky Mixer AR-100 (THINKYMIXER (Non Vacuum) AR-100)) to prepare a sample. The stirring conditions were 3 minutes after stirring, 0 minute defoaming, and 70 g for balance adjustment.
(ii) One drop of sample was set between a 5-window type cover glass and a slide glass, and then observed and photographed with a digital microscope (manufactured by Keyence Corporation, VHX-500). Two to three images were taken at a magnification of 700 and evaluated according to the following criteria.
Evaluation criteria:
Uniform dispersion throughout (aggregation rate is less than 10%): A
Dispersed throughout (aggregation rate is 10% or more and less than 30%): B
Partial aggregation (aggregation ratio is 30% or more and less than 70%): C
Aggregate as a whole (aggregation rate is 70% or more): D
(In the evaluation criteria, A evaluation is the best.)

[Time until uniform dispersion]
(i) Put 0.50 g of polymer particles into a 50 cc sample bottle and add 5.0 g of toluene. After that, it is dispersed for 5 minutes using an ultrasonic cleaner.
(ii) 0.3 g of an acrylic resin (manufactured by DIC, "Acrydic (registered trademark) A-814") is added, and then dispersed for 5 minutes using an ultrasonic cleaner to prepare a sample.
(iii) The viscosity of the prepared sample is measured at 10-minute intervals using an ultra-trace sample viscometer ("m-VROC" manufactured by Leosence) until the rate of change in viscosity is less than 3%.
The time until the rate of change in viscosity becomes less than 3% and the viscosity stabilizes is defined as the time until uniform dispersion.

[optical properties]
Using the polymer particles obtained in Examples 1-17 and Comparative Examples 1-10, resin compositions were prepared.
The resin composition was coated on one side of a transparent polyester film so as to have a dry film thickness of X μm to prepare an optical film.
A test piece was obtained by cutting an optical film into a square shape of 6 cm × 6 cm. The haze of is measured according to JIS K 7136 with a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., "NDH-4000"). Then, using the maximum value, minimum value, and average value of the haze (%) measured at the five locations, the haze difference (%) is calculated by the following formula, and the haze difference (%) is evaluated as follows. Evaluated according to the standard.

<Formula for haze difference (%)>
R=[(HzMAX−HzMIN)/HzAVE]×100
R: Haze difference (%)
HzMAX: maximum value of haze (%) at 5 locations HzMIN: minimum value of haze (%) at 5 locations HzAVE: average value of haze (%) at 5 locations

<Evaluation Criteria>
A: Haze difference is less than 0.4% B: Haze difference is 0.4% or more and less than 1.0% C: Haze difference is 1.0% or more and less than 2.0% D: Haze difference is 2.0% or more (In the evaluation criteria, A evaluation is the best.)

[Production example of seed particles]
[Production Example 1 of Seed Particles]
A separable flask equipped with a stirrer, a thermometer and a reflux condenser was charged with 1300 g of water as an aqueous medium, 70 g of methyl methacrylate as a (meth)acrylic acid ester-based monomer, and n-octyl as a molecular weight modifier. 0.70 g of mercaptan was charged, and the inside of the separable flask was replaced with nitrogen while stirring the contents of the separable flask, and the internal temperature of the separable flask was raised to 70°C. Furthermore, while maintaining the internal temperature of the separable flask at 70° C., an aqueous solution obtained by dissolving 0.35 g of potassium persulfate as a polymerization initiator in 50 g of water was added to the contents of the separable flask, followed by polymerization for 5 hours. reacted.
After that, 256 g of methyl methacrylate and 2.56 g of n-octyl mercaptan as a molecular weight modifier were newly charged and introduced into the polymerization reaction solution. was heated to 70°C. While maintaining the internal temperature of the separable flask at 70° C., an aqueous solution prepared by dissolving 1.28 g of potassium persulfate as a polymerization initiator in 50 g of water was added to the contents of the separable flask, and then the polymerization reaction was carried out for 12 hours. let me
The reaction solution after polymerization was filtered through a wire mesh of 400 mesh (opening of 32 μm) to prepare a slurry containing 20% by mass of seed particles (referred to as seed particles (1)) composed of polymethyl methacrylate as a solid content. The seed particles (1) contained in this slurry were true spherical particles with a volume average particle diameter of 0.54 μm.

[Production Example 2 of Seed Particles]
3300 g of water as an aqueous medium, 400 g of methyl methacrylate as a (meth)acrylic acid ester-based monomer, and 2 n-octyl mercaptans as a molecular weight modifier are placed in a 5-liter reactor equipped with a stirrer and a thermometer. A slurry of seed particles (1) produced in Seed Particle Production Example 1 was added so that the solid content (seed particles) was 40.0 g, and the inside was replaced with nitrogen while stirring the contents. Then, the internal temperature of the reactor was raised to 70°C. Further, while maintaining the internal temperature of the reactor at 70° C., an aqueous solution prepared by dissolving 2.0 g of potassium persulfate as a polymerization initiator in 60 g of water was added to the contents of the reactor, followed by polymerization for 12 hours. rice field.
The reaction solution after polymerization was filtered through a wire mesh of 400 mesh (32 μm opening) to prepare a slurry containing 20% by mass of seed particles (hereinafter referred to as seed particles (2)) made of polymethyl methacrylate as a solid content. . The seed particles (2) contained in this slurry were true spherical particles with a volume average particle diameter of 1.02 μm.

[Production Example 3 of Seed Particles]
3500 g of water as an aqueous medium, 500 g of methyl methacrylate as a (meth)acrylic acid ester-based monomer, and 5 n-octyl mercaptan as a molecular weight modifier are placed in a 5-liter reactor equipped with a stirrer and a thermometer. A slurry of seed particles (1) produced in Seed Particle Production Example 1 was added so that the solid content (seed particles) was 40.0 g, and the inside was replaced with nitrogen while stirring the contents. Then, the internal temperature of the reactor was raised to 70°C. Furthermore, while maintaining the internal temperature of the reactor at 70° C., an aqueous solution obtained by dissolving 5.0 g of 2,2′-azobis(2,4-dimethylvaleronitrile) as a polymerization initiator in 60 g of water was added to the inside of the reactor. After adding to the contents, the polymerization reaction was carried out for 12 hours. After that, the internal temperature of the reactor was raised to 70° C., and the reaction was carried out for 1 hour and 30 minutes. The reaction solution after polymerization was filtered through a wire mesh of 400 mesh (32 μm opening) to prepare a slurry containing 20% by mass of seed particles (hereinafter referred to as seed particles (3)) composed of polymethyl methacrylate as a solid content. . The seed particles (3) contained in this slurry were true spherical particles with a volume average particle diameter of 2.30 μm.

[Production of polymer particles: Example 1]
(1) Polymerization step 300 g of methyl methacrylate (MMA), 200 g of styrene (St), 300 g of ethylene glycol methacrylate (EGDMA), and 9.7 g of 2,4-dimethylvaleronitrile (polymerization initiator) are dissolved to obtain a monomer. A body mixture was prepared.
The above monomer mixture, sodium di(2-ethylhexyl) sulfosuccinate in 900 g of ion-exchanged water (manufactured by NOF Corporation, product name “Rapizol (registered trademark) A-80”, solubility in water at a liquid temperature of 25 ° C.; 1.5 g / 100 ml; an anionic surfactant (other surfactant) having no polyoxyalkylene chain) was mixed with an aqueous surfactant solution containing 15 g of pure content, and a homomixer (manufactured by Primix Co., Ltd.) TK Homomixer MARK II 2.5") and treated at 8000 rpm for 10 minutes to obtain an emulsified liquid. To this emulsion, the seed particle slurry obtained in Seed Particle Production Example 1 was added so that the solid content (seed particles) was 18.75 g, and the mixture was stirred at 30°C for 5 hours to obtain a dispersion. .
To this dispersion, polyoxyethylene nonylphenyl ether sodium phosphate (manufactured by Toho Chemical Co., Ltd., product name “Phosphanol (registered trademark) LO-529”; anionic surfactant having a polyoxyalkylene chain) is purely added. 2250 g of an aqueous solution in which 15 g was dissolved was added, and then the mixture was stirred at 75° C. for 4 hours and then at 100° C. for 1.5 hours to carry out a polymerization reaction to obtain a slurry of polymer particles.

(2) Solid-Liquid Separation Step The obtained slurry of polymer particles was put into the pressure container of the pressure filter, and the slurry of the polymer particles was filled on the filter cloth in the pressure container. After that, the pressurized inside of the pressure vessel (the space above the filter medium) was supplied by supplying the compressed gas to the space above the filter medium in the pressure vessel by means of the compressed gas supplier.
As a result, the polymer particle slurry was subjected to pressure filtration and dehydration, and the aqueous medium (water) was removed as a filtrate from the polymer particle slurry. Deliquoring was performed at a rate of 0.061 [kg/min·m ² ] until 78% of the charged water was recovered as filtrate. As a result, a cake of polymer particles was obtained on the filter medium.

(3) Washing step The filtrate port and the filtrate outlet of the pressure filter are closed, and while the polymer particle cake is held on the filter medium, water at 60°C is supplied as a washing liquid in an amount twice that of the polymer particles. and soaked for 1 hour. After that, the inside of the pressure vessel (the space above the filter medium) was pressurized by supplying the compressed gas to the space above the filter medium in the pressure vessel by means of the compressed gas supplier.
As a result, pressure filtration and dehydration were carried out, the cake of the polymer particles was washed, water after washing was removed as a filtrate, and polymer particles after washing were obtained on the filter medium. The filtration rate was set to 0.100 [kg/min·m ² ], and washing was carried out until 95% of the washing liquid was collected at the filtrate outlet.

(4) Drying step The polymer particles after washing obtained in the washing step are warmed in advance to 60°C, and the weight measured by the Karl Fischer method using a vacuum dryer (vacuum stirring dryer (crushing dryer)). Drying was performed until the water content of the coalesced particles became less than 1.0% by mass.
The conditions of the drying process were a degree of vacuum of −0.075 MPa, a drying temperature of 60° C., a drying time of 8 hours, and a stirring shear coefficient of 2,323.

(5) Classification step (removal of coarse particles)
The polymer particles after drying obtained in the drying step are subjected to an air classifier ("Turbo Classifier (registered trademark) TC-15" manufactured by Nisshin Engineering Co., Ltd.) to determine the particle size of the desired polymer particles. The polymer particles were obtained by classifying so as to remove particles having a particle diameter of 2.5 times or more.

[Production of polymer particles: Example 2]
As an anionic surfactant (another surfactant) having no polyoxyalkylene chain, 10 g of pure sodium alkenyl succinate was used.
In the drying process, the degree of vacuum was set to -0.100 MPa, and the stirring shear coefficient was set to 2,441.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Example 3]
The solid-liquid separation process was carried out until 79% of the charged water was recovered as filtrate.
In the drying process, the degree of vacuum was set to -0.050 MPa, and the stirring shear coefficient was set to 1,983.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Example 4]
The monomer composition was 300 g methyl methacrylate (MMA), 200 g styrene (St), 300 g ethylene glycol methacrylate (EGDMA), and 45 g polyethylene glycol-propylene glycol-monomethacrylate.
As an anionic surfactant having a polyoxyalkylene chain, 15 g of pure polyoxyethylene styrenated phenyl ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name "Plysurf AL") was used.
The solid-liquid separation process was carried out until 79% of the charged water was recovered as filtrate.
The washing step operation was repeated three times.
In the drying process, the degree of vacuum was -0.075 MPa, and the stirring shear coefficient was 2,475.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Example 5]
The monomer composition was 300 g methyl methacrylate (MMA), 200 g styrene (St), 300 g ethylene glycol methacrylate (EGDMA), and 45 g polyethylene glycol-propylene glycol-monomethacrylate.
As an anionic surfactant having a polyoxyalkylene chain, 15 g of pure polyoxyethylene lauryl ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name "Plysurf A210G") was used.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Example 6]
The monomer composition was 300 g methyl methacrylate (MMA), 200 g styrene (St), 300 g ethylene glycol methacrylate (EGDMA), and 45 g polyethylene glycol-propylene glycol-monomethacrylate.
As an anionic surfactant having no polyoxyalkylene chain (another surfactant), 25 g of pure sodium di(2-ethylhexyl)sulfosuccinate was used.
As an anionic surfactant having a polyoxyalkylene chain, 15 g of a pure polyoxyethylene alkyl ether phosphate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name "Plysurf A208F") was used.
In the washing process, the filtration rate was set to 0.200 [kg/min·m ² ].
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Example 7]
The monomer composition was 900 g of styrene (St) and 108 g of divinylbenzene (DVB).
As an anionic surfactant having a polyoxyalkylene chain, 15 g of pure polyoxyethylene styrenated phenyl ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name "Plysurf AL") was used.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Example 8]
As an anionic surfactant having a polyoxyalkylene chain, 35 g of pure polyoxyethylene styrenated phenyl ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name "Plysurf AL") was used.
In the solid-liquid separation step, the dewatering rate was set to 0.070 [kg/min·m ² ], and the process was continued until 80% of the charged water was collected as a filtrate.
In the washing process, the filtration rate was set to 0.200 [kg/min·m ² ].
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Example 9]
In the solid-liquid separation step, the dewatering rate was set to 0.030 [kg/min·m ² ], and 83% of the charged water was collected as filtrate.
In the washing process, the filtration rate was set to 0.035 [kg/min·m ² ].
In the drying process, the degree of vacuum was set to -0.100 MPa, and the stirring shear coefficient was set to 2056.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Example 10]
A slurry of seed particles (2) obtained in Seed Particle Production Example 2 was used as a slurry of seed particles, and the amount thereof used was 6.3 g as a solid content (seed particles).
The monomer composition was 560 g methyl methacrylate (MMA) and 300 g ethylene glycol methacrylate (EGDMA).
As an anionic surfactant having no polyoxyalkylene chain (another surfactant), 5 g of pure sodium di(2-ethylhexyl)sulfosuccinate was used.
In the washing process, the filtration rate was set to 0.085 [kg/min·m ² ].
In the drying process, the vacuum degree was -0.060 MPa, and the stirring shear coefficient was 2030.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Example 11]
The slurry of the seed particles (1) was used as the slurry of the seed particles (3) obtained in Seed Particle Production Example 3, and the amount used was 4.7 g as a solid content (seed particles).
The monomer composition was 560 g methyl methacrylate (MMA) and 300 g ethylene glycol methacrylate (EGDMA).
As an anionic surfactant having a polyoxyalkylene chain, 20 g of pure polyoxyethylene styrenated phenyl ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name "Plysurf AL") was used.
In the drying process, the degree of vacuum was -0.060 MPa, the drying time was 9 hours, and the stirring shear coefficient was 2,579.
Polymer particles of interest were obtained in the same manner as in Example 10 except for the above.

[Production of polymer particles: Example 12]
As an anionic surfactant having no polyoxyalkylene chain (another surfactant), 15 g of pure sodium lauryl sulfate was used.
In the drying process, the stirring shear coefficient was set to 2545.
Polymer particles of interest were obtained in the same manner as in Example 11 except for the above.

[Production of polymer particles: Example 13]
As an anionic surfactant (another surfactant) having no polyoxyalkylene chain, 15 g of pure sodium lauryl sulfate was used.
As an anionic surfactant having a polyoxyalkylene chain, 13 g of pure polyoxyethylene lauryl ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name "Plysurf A210G") was used.
In the drying process, the stirring shear coefficient was set to 2709.
Polymer particles of interest were obtained in the same manner as in Example 11 except for the above.

[Production of polymer particles: Example 14]
As an anionic surfactant having a polyoxyalkylene chain, 15 g of pure polyoxyethylene glyceryl caprylate was used.
In the drying process, the agitation shear coefficient was set to 2673.
Polymer particles of interest were obtained in the same manner as in Example 11 except for the above.

[Production of polymer particles: Example 15]
As an anionic surfactant having a polyoxyalkylene chain, 13 g of pure polyoxyethylene styrenated phenyl ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name "Plysurf AL") was used.
In the solid-liquid separation step, the dewatering rate was set to 0.065 [kg/min·m ² ], and the process was continued until 80% of the charged water was collected as a filtrate.
In the washing process, the filtration rate was set to 0.150 [kg/min·m ² ].
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Example 16]
As an anionic surfactant having a polyoxyalkylene chain, 35 g of polyoxyethylene styrenated phenyl ether phosphate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name "Plysurf AL") was used as a pure content.
In the solid-liquid separation step, the dewatering rate was set to 0.070 [kg/min·m ² ], and the process was continued until 80% of the charged water was collected as a filtrate.
In the washing step, the polymer particles were immersed for 0.5 hours by supplying water at 60° C. in an amount twice that of the polymer particles as a washing liquid.
In the drying process, the stirring shear coefficient was set to 2376.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Example 17]
As an anionic surfactant having a polyoxyalkylene chain, 35 g of pure polyoxyethylene styrenated phenyl ether phosphate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name "Plysurf AL") was used.
In the solid-liquid separation step, the dewatering rate was set to 0.055 [kg/min·m ² ], and the process was continued until 80% of the charged water was collected as a filtrate.
In the washing step, twice as much water as the polymer particles was supplied as a washing liquid at 60° C., and the particles were immersed for 0.5 hours, and the filtration rate was set to 0.085 [kg/min·m ² ].
In the drying process, the degree of vacuum was set to -0.055 MPa, and the stirring shear coefficient was set to 2,344.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Comparative Example 1]
As an anionic surfactant having a polyoxyalkylene chain, 10 g of pure polyoxyethylene nonylphenyl ether sodium phosphate (manufactured by Toho Chemical Co., Ltd., product name “Phosphanol (registered trademark) LO-529”) is used. did.
The washing process was repeated 5 times.
In the drying process, the vacuum degree was -0.085 MPa, and the stirring shear coefficient was 2,620.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Comparative Example 2]
To the composition of Example 1 was added 45 g of the hydrophilic monomer polyethylene glycol-propylene glycol-monomethacrylate.
In the solid-liquid separation step, the dewatering rate was set to 0.100 [kg/min·m ² ], and 80% of the charged water was collected as filtrate.
In the washing process, the filtration rate was set to 0.300 [kg/min·m ² ].
In the drying process, the agitation shear coefficient was set to 2553.
Otherwise, the same procedure as in Comparative Example 1 was carried out to obtain the desired polymer particles.

[Production of polymer particles: Comparative Example 3]
The monomer composition was 300 g methyl methacrylate (MMA), 200 g styrene (St), 300 g ethylene glycol methacrylate (EGDMA), and 45 g polyethylene glycol-propylene glycol-monomethacrylate.
As an anionic surfactant having no polyoxyalkylene chain (another surfactant), 35 g of pure sodium di(2-ethylhexyl)sulfosuccinate was used.
As an anionic surfactant having a polyoxyalkylene chain, 15 g of pure polyoxyethylene styrenated phenyl ether phosphate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name "Plysurf AL") was used.
Except for the above, the desired polymer particles were obtained in the same manner as in Example 1.

[Production of polymer particles: Comparative Example 4]
In the solid-liquid separation step, the dewatering speed was set to 0.020 [kg/min·m ² ].
In the drying process, the degree of vacuum was -0.090 MPa, and the shear coefficient of stirring was 2,620.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Comparative Example 5]
As an anionic surfactant having a polyoxyalkylene chain, 15 g of pure polyoxyethylene styrenated phenyl ether phosphate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name "Plysurf AL") was used.
In the drying process, the degree of vacuum was -0.020 MPa and the stirring shear coefficient was 1,260.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Comparative Example 6]
As an anionic surfactant having a polyoxyalkylene chain, 15 g of pure sodium polyoxyethylene lauryl ether phosphate was used.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Comparative Example 7]
As an anionic surfactant having a polyoxyalkylene chain, 15 g of pure polyoxyethylene sorbitan monostearate was used.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Comparative Example 8]
As an anionic surfactant having no polyoxyalkylene chain (another surfactant), 15 g of pure isopropyl palmitate was used.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Comparative Example 9]
As an anionic surfactant having no polyoxyalkylene chain (another surfactant), 15 g of pure sorbitan trioleate was used.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

[Production of polymer particles: Comparative Example 10]
As an anionic surfactant having no polyoxyalkylene chain (another surfactant), 15 g of pure isopropyl palmitate was used.
As an anionic surfactant having a polyoxyalkylene chain, 15 g of pure sodium polyoxyethylene lauryl ether phosphate was used.
In the drying process, the degree of vacuum was -0.015 MPa and the stirring shear coefficient was 996.
The desired polymer particles were obtained in the same manner as in Example 1 except for the above.

Regarding Examples 1 to 17 and Comparative Examples 1 to 10, the volume average particle diameter, CV value, gel fraction, specific surface area, type and SP value of each surfactant, polymer particle unit of the obtained polymer particles Tables 2 to 4 show the amount of each surfactant per surface area, the amount of non-volatile components per unit surface area of polymer particles, the viscosity measurement results, the dispersibility, the time until uniform dispersion, and the optical properties.

Symbols in Tables 2, 3 and 4 are as follows.
a: POEPS: Phosphanol LO-529 (manufactured by Toho Chemical Industry Co., Ltd.)
→ Sodium polyoxyethylene nonylphenyl ether phosphate b: POSPS: Plysurf AL (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
→ Polyoxyethylene styrenated phenyl ether phosphate c: POELE: Plysurf A210G (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
→ Polyoxyethylene lauryl ether phosphate d: POEAS: Plysurf A208F (Daiichi Kogyo Seiyaku Co., Ltd.)
→ Polyoxyethylene alkyl ether phosphate e: POEKG: Polyoxyethylene glyceryl caprylate f: POERS: Sodium polyoxyethylene lauryl ether phosphate g: POESM: Polyoxyethylene sorbitan monostearate

i: DSS: Rapisol A-80 (manufactured by NOF Corporation)
→ Di(2-ethylhexyl) sodium sulfosuccinate
ii: ASK: sodium alkenyl succinate
iii: RSN: sodium lauryl sulfate
iv: PAI: isopropyl palmitate v: TOS: sorbitan trioleate

The invention may be embodied in many other forms without departing from its spirit or essential characteristics. Therefore, the above-described embodiments are merely illustrative in all respects and should not be construed in a restrictive manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Furthermore, all modifications and changes within the equivalent range of claims are within the scope of the present invention.

Claims (9)

(a) The content of the surfactant having a solubility parameter (SP value) of 9.0 to 12.0 and having a polyoxyalkylene chain is 1.0×10 ⁻³ to 6.0×10 −3 per unit surface area of the polymer particles. 0×10 ⁻³ g/m ² ,
(b) the content of the surfactant having a solubility parameter (SP value) of 9.0 to 12.0 and having no polyoxyalkylene chain is 5.0 × 10 ^-5 to 13 per unit surface area of the polymer particle; .0×10 ⁻⁵ g/m ² ,
(c) the surface residual amount of non-volatile components is 2.0×10 ⁻³ g/m ² or less per unit surface area of the polymer particles;
is a polymer particle. 2. The polymer particles according to claim 1, which have a volume average particle diameter of 1 to 20 μm and a coefficient of variation (CV value) of the particle diameter of the polymer particles obtained by the following formula of 15% or less.
Variation coefficient (CV value) of particle size of polymer particles = (standard deviation of volume-based particle size distribution of polymer particles/volume average particle size of polymer particles) x 100 3. The polymer particles according to claim 1, wherein the surfactant having a polyoxyalkylene chain with an SP value of 9.0 to 12.0 is a phosphate ester anionic surfactant. (Meth)acrylic polymer, styrenic polymer, and (meth)acrylic-styrenic copolymer according to any one of claims 1 to 3, composed of one or more polymers selected from the group consisting of polymer particles. 5. The polymer particles according to any one of claims 1 to 4, which are used for optical members. 5. The polymer particles according to any one of claims 1 to 4, which are used as additives for paints. 5. The polymer particles according to any one of claims 1 to 4, which are used as an antiblocking agent. A resin composition comprising the polymer particles according to any one of claims 1 to 4 and a resin binder. An optical member comprising a layer of the resin composition according to claim 8 on a substrate.