KR20200132863A - Colored organic resin particles and manufacturing method thereof - Google Patents

Abstract

The present invention provides a colored organic resin particle having a sufficiently high volume resistivity and high dispersibility in a solvent. Specifically, the present invention is a colored organic resin particle composed of a core portion made of resin particles derived from a polymerizable vinyl-based monomer and a shell portion made of a π-conjugated polymer compound on the surface of the core portion, and the volume resistivity is 1×10 ^{3 to} 1×10 ⁸ (Ω·cm), and in the color difference measurement based on JIS Z 8781-5 “color display method-L*a*b* color system”, the following equation: 10≦ΔE'=L *+|a*|+|b*|≤48 (in the formula, ΔE' represents blackness, L* represents brightness, and a* and b* represent color coordinates) to provide.

Description

Colored organic resin particles and manufacturing method thereof

The present invention relates to colored organic resin particles and a method for producing the same.

Conventionally, in a liquid crystal display (LCD) or the like, it is known to use a resin particle having a predetermined particle diameter as a spacer in order to properly maintain the thickness of the liquid crystal layer by forming a gap between two substrates. As the resin particles for spacers, colored resin particles are used, in particular, from the viewpoint of improving the image quality by improving the contrast of a color liquid crystal panel.

For example, Patent Document 1 describes a method for producing colored resin particles having a core-shell structure in which a polymer obtained by oxidative polymerization of an aromatic amine monomer is present on the entire surface of polymer fine particles obtained by polymerization of an ethylenically unsaturated monomer. have.

In addition, Patent Document 2 discloses a resin particle formed of a polymerizable vinyl-based monomer, and a colored resin particle having a core-shell structure composed of a coating layer as a colorant covering the surface of the resin particle, wherein the coating layer contains a π-conjugated polymer compound. The colored resin particles to be included are described.

Japanese Patent Laid-Open Publication No. 2007-254558 International Publication No. 2012/042918

Since the colored fine particles obtained by the production method described in Patent Document 1 have low dispersibility in a solvent, there is a problem that the colored fine particles aggregate in a solvent.

The colored resin particles described in Patent Document 2 have a large amount of π-conjugated polymer compound coated and not subjected to undoping treatment, so that the amount of anions such as sulfate ions as a dopant contained in the coating layer increases. Thus, there is a problem that the conductivity of the colored resin particles increases. Further, there is a problem that the volume resistivity of the colored resin particles decreases due to an increase in the conductivity of the colored resin particles.

Accordingly, it is an object of the present invention to provide colored organic resin particles having a sufficiently high volume resistivity and high dispersibility in a solvent.

The inventors of the present invention have conducted extensive research in order to achieve the above object, and as a result, a colored organic resin composed of a core part made of resin particles derived from a polymerizable vinyl monomer, and a shell part made of a π-conjugated polymer compound on the surface of the core part. It was found that by controlling the amount of dopant contained in the shell portion of the particles, colored organic resin particles that solve the above object were obtained. The present invention is based on these findings and has been completed through further studies.

That is, the present invention provides the invention of the aspect to be posted below.

Item 1. A colored organic resin particle comprising a core portion made of resin particles derived from a polymerizable vinyl monomer, and a shell portion made of a π-conjugated polymer compound on the surface of the core portion,

The volume resistivity is 1×10 ³ ∼ 1×10 ⁸ (Ω·cm), and

In the color difference measurement based on JIS Z 8781-5 "Color Display Method-L*a*b* Color System", the following equation:

10≤ΔE'=L*+｜a*｜+｜b*｜≤48

(In the formula, ΔE' represents blackness, L* represents brightness, and a* and b* represent color coordinates)

Colored organic resin particles satisfying the relational expression represented by.

Item 2. The polymerizable vinyl monomer is at least one selected from the group consisting of a monofunctional (meth)acrylic acid ester monomer, a polyfunctional (meth)acrylic acid ester monomer, a monofunctional styrene monomer, and a polyfunctional styrene monomer. The colored organic resin particles according to item 1 which are monomers.

Item 3. The colored organic resin particles according to item 1 or 2, wherein the π-conjugated polymer compound is a polymer of a nitrogen-containing heteroaromatic compound.

Item 4. As the colored organic resin particles according to any one of items 1 to 3,

The colored organic resin particles in which the content of the sulfur element in the colored organic resin particles measured by fluorescence X-ray analysis is 0.12% by mass or less.

Item 5. As the colored organic resin particles according to any one of items 1 to 4,

The colored organic resin particles, wherein the colored organic resin particles have a volume average particle diameter of 1 to 100 µm, and a coefficient of variation of the volume-based particle diameter of the colored organic resin particles is 20% or less.

Item 6. The colored organic resin particles according to any one of items 1 to 5 used as a light control device or a spacer of a light control film.

Item 7. As a method for producing colored organic resin particles according to any one of items 1 to 6,

A step of forming a core shell structure by covering the surface of a core portion made of resin particles obtained by polymerizing a polymerizable vinylic monomer in an aqueous medium with a shell portion made of a polymer compound having conjugated π electrons;

A step of dispersing the core shell structure in an alkaline aqueous solution, and

A method for producing colored organic resin particles comprising a step of separating and washing the core shell structure from the alkaline aqueous solution.

According to the present invention, it is possible to provide colored organic resin particles having a sufficiently high volume resistivity and high dispersibility in a solvent.

Hereinafter, preferred embodiments of the present invention will be described in detail.

The present invention includes colored organic resin particles and a method for producing the same. In the present specification, the term "high dispersibility in a solvent" means a state in which the dispersed colored organic resin particles are dispersed in the state of primary particles when the colored organic resin particles and water or organic solvent are mixed, and the dispersed colored organic resin particles are It means that the resin particles are not in the state of secondary particles such as aggregation, and are not dissolved with each other.

In this specification, (meth)acrylic means acrylic or methacrylic, and "(meth)acrylate" means acrylate or methacrylate.

1. Colored organic resin particles

The colored organic resin particles of the present invention have a core portion made of resin particles derived from a polymerizable vinyl-based monomer, and a core-shell structure formed of a shell portion made of a ?-conjugated polymer compound on the surface of the core portion.

The colored organic resin particles of the present invention are composed of a core portion made of resin particles derived from a polymerizable vinyl-based monomer, and a shell portion made of a ?-conjugated polymer compound on the surface of the core portion. That is, the colored organic resin particles of the present invention are colored organic resin particles having a core-shell structure.

The shell portion made of the ?-conjugated polymer compound is disposed on the surface of the core portion made of resin particles derived from a polymerizable vinyl-based monomer. That is, the shell portion made of the ?-conjugated polymer compound covers the entire surface of the core portion made of resin particles derived from the polymerizable vinyl-based monomer.

In the colored organic resin particles of the present invention, the ?-conjugated polymer compound is preferably a nitrogen-containing heteroaromatic compound.

The colored organic resin particles of the present invention have a volume resistivity of 1×10 ^{3 to} 1×10 ⁸ (Ω·cm), and are based on JIS Z 8781-5 “color display method-L*a*b* color system”. For color difference measurement, the following equation:

10≤ΔE'=L*+｜a*｜+｜b*｜≤48

(In the formula, ΔE' represents blackness, L* represents brightness, and a* and b* represent color coordinates)

Satisfies the relational expression expressed as

(Volume resistivity)

The colored organic resin particles of the present invention have a volume resistivity in the range of 1×10 ^{3 to} 1×10 ⁸ (Ω·cm). When the volume resistivity is less than 1×10 ³ (Ω·cm), the dimming device or the dimming film is shorted when the colored organic resin particles are used as a dimming device or a spacer of a dimming film.

When the volume resistivity is less than 1×10 ³ (Ω·cm), the dispersibility of the colored organic resin particles in a polar solvent such as water, alcohol, or ester is low, and an aggregate of colored organic resin particles is formed. When the volume resistivity is larger than 1×10 ⁸ (Ω·cm), the shell portion is removed from the colored organic resin particles, thereby inhibiting the coloring of the colored organic resin particles.

The volume resistivity of the colored organic resin particles is preferably 1×10 ^{4 to} 8×10 ⁷ (Ω·cm), from the viewpoint of improving dispersibility in the polar solvent, and 2.5×10 ⁴ to 7×10 ⁷ ( Ω·cm), more preferably 5×10 ⁴ to 6×10 ⁷ (Ω·cm), and particularly preferably 1×10 ^{5 to} 5×10 ⁷ (Ω·cm). The method of measuring the volume resistivity is as described in Examples.

(Color difference)

In the color difference measurement based on JIS Z 8781-5 "color display method -L*a*b* color system", the colored organic resin particles of the present invention, the following formula:

10≤ΔE'=L*+｜a*｜+｜b*｜≤48

(In the formula, ΔE' represents blackness, L* represents brightness, and a* and b* represent color coordinates)

Satisfies the relational expression represented by That is, the colored organic resin particles of the present invention are black organic resin particles.

In the present specification, as the coating amount of the π-conjugated polymer compound forming the shell portion to the core portion increases, the colored portion increases, so that the blackness of the colored organic resin particles increases.

When ΔE'<10, since black appears too strongly, transmission of light is inhibited. On the other hand, when ΔE'>48, since the blackness of the colored organic resin particles of the present invention is insufficient, white color appears strong, and the target blackness cannot be achieved.

ΔE' is preferably 12≤ΔE'≤46, more preferably 14≤ΔE'≤44, more preferably 16≤ΔE'≤42, and particularly preferably 18≤ΔE'≤40.

In the present invention, when the coating amount of the ?-conjugated polymer compound forming the shell portion is 30% by mass or less based on the total mass of the core portion, the value of ?E' is 10 or more.

In the present invention, when the coating amount of the ?-conjugated polymer compound forming the shell portion is 1% by mass or more based on the total mass of the core portion, the value of ?E' is 48 or less.

The mass ratio of the core part and the shell part constituting the colored organic resin particles of the present invention can be calculated from the ratio of the amount of the polymerizable vinyl-based monomer used in the production of the core part and the amount of nitrogen-containing aromatic compound used in the production of the shell part. have.

The detailed blackness measurement method is as described in Examples.

(Content of sulfur element in colored organic resin particles)

In the present invention, since the anion such as sulfate ion is a dopant, the content of the sulfur element in the colored organic resin particles is the content of the residual dopant contained in the shell portion made of a π-conjugated polymer compound (a coating layer containing a polymer of a nitrogen-containing aromatic compound) Corresponds to

In the present invention, the upper limit of the sulfur element content in the colored organic resin particles measured by fluorescence X-ray analysis is preferably 0.12% by mass, more preferably 0.10% by mass, and 0.09% by mass from the viewpoint of dispersibility in the solvent. Is more preferable, and 0.08 mass% is especially preferable.

In the present invention, the lower limit of the content of the sulfur element in the colored organic resin particles measured by fluorescence X-ray analysis is preferably 0.005% by mass, more preferably 0.008% by mass, and 0.01% by mass from the viewpoint of dispersibility in the solvent. Is more preferable, and 0.012 mass% is particularly preferable.

Among the upper and lower limits of the content, when the content of the sulfur element in the colored organic resin particles measured by fluorescence X-ray analysis is 0.012% by mass to 0.08% by mass, the dispersibility of the colored organic resin particles in the solvent is remarkable. Is improved.

(Volume average particle diameter in colored organic resin particles and coefficient of variation of particle diameter based on volume)

In the colored organic resin particles of the present invention, it is preferable that the volume average particle diameter of the colored organic resin particles is 1 to 100 μm, and the coefficient of variation of the particle diameter based on the volume of the colored organic resin particles is 20% or less. When the volume average particle diameter of the colored organic resin particles is within the above range, the coating formation of the shell portion is stabilized. Further, when the coefficient of variation of the particle diameter based on the volume of the colored organic resin particles is within the above range, the function as a spacer is improved.

It is more preferable that the volume average particle diameter of the colored organic resin particles is 1.2 to 75 µm, and the coefficient of variation of the volume-based particle diameter of the colored organic resin particles is 16% or less. When the volume average particle diameter of the colored organic resin particles is within the above range, the coating formation of the shell portion is more stable. Further, when the coefficient of variation of the particle diameter based on the volume of the colored organic resin particles is within the above range, the function as a spacer is further improved.

It is more preferable that the volume average particle diameter of the colored organic resin particles is 1.4 to 50 µm, and the coefficient of variation of the volume-based particle diameter of the colored organic resin particles is 14% or less. When the volume average particle diameter of the colored organic resin particles is within the above range, the coating formation of the shell portion is more stable. Further, when the coefficient of variation of the particle diameter based on the volume of the colored organic resin particles is within the above range, the function as a spacer is further improved.

(Use of colored organic resin particles)

It is preferable that the colored organic resin particle of this invention is used as a light control device or a spacer of a light control film. Specifically, it is used in the field of various devices such as liquid crystal spacers and smart window devices (light modulators).

1-1. Core portion made of resin particles derived from polymerizable vinyl monomers

The method for producing the resin particles derived from the polymerizable vinyl monomer is not limited, but, for example, the seed particles are preferably absorbed by the polymerizable vinyl monomer in the aqueous emulsion to polymerize the absorbed polymerizable vinyl monomer. Can be manufactured.

<Seed Particle>

It is preferable that the seed particle is a resin particle derived from a monomer for seed particle production. Seed particles can be prepared by applying a known method. For example, seed particles can be produced by applying the method described in International Publication No. 2013/030977.

As a monomer for producing seed particles, for example, (meth) methyl acrylate, (meth) ethyl acrylate, (meth) acrylate n-propyl, (meth) acrylate isopropyl, (meth) acrylate n-butyl, (meth) acrylate iso And (meth)acrylic acid C _1-4 alkyl ester monomers such as butyl and t-butyl (meth)acrylate. These monomers may be used alone or in combination of two or more.

The weight average molecular weight of the seed particles is usually 150,000 to 1 million, and preferably 200,000 to 800,000 as measured by GPC (gel permeation chromatography).

Meanwhile, the size and shape of the seed particles are not particularly limited. As the seed particles, spherical particles having a particle diameter of 0.1 to 5 μm are usually used. The particle diameter of the seed particle can be measured with a laser diffraction scattering particle size distribution measuring device.

<Method of manufacturing seed particles>

The method for producing the seed particles is not particularly limited, and known methods such as emulsion polymerization, soap-free emulsion polymerization, seed polymerization, and suspension polymerization can be used. The production method is preferably emulsion polymerization, soap-free emulsion polymerization, and seed polymerization in view of the uniformity of the particle diameter of the seed particles and the simplicity of the production method. The weight average molecular weight of the seed particles can be adjusted by the amount of the polymerization initiator used or the molecular weight modifier added.

As an aqueous medium for producing the seed particles, for example, water or a mixed solvent of water and an organic solvent (eg, a hydrophilic organic solvent such as a lower alcohol having 5 or less carbon atoms) may be mentioned.

Polymerization can be carried out in the presence of a polymerization initiator. Known polymerization initiators can be widely used as the polymerization initiator, and examples thereof include peroxides such as benzoyl peroxide, lauroyl peroxide, and tert-butylperoxyisobutyrate; Children such as 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), and 2,2-azobis-(2-methylpropionate) Crude compound; And peroxide salts such as potassium persulfate and ammonium persulfate. It is preferable to use the polymerization initiator in the range of 0.1 to 10 parts by mass per 100 parts by mass of the monomer for producing seed particles.

Polymerization can be carried out in the presence of a molecular weight modifier. As a molecular weight modifier, α-methylstyrene dimer; mercaptans such as n-octyl mercaptan (1-octane thiol) and t-dodecyl mercaptan; terpenes such as t-terpinene and dipentene; Chain transfer agents such as halogenated hydrocarbons (eg, chloroform, carbon tetrachloride) can be used. It is preferable to use a molecular weight modifier in the range of 0.1-10 mass parts with respect to 100 mass parts of monomers for seed particle production.

The polymerization can be carried out in the presence of a dispersion stabilizer. Examples of the dispersion stabilizer include polyvinyl alcohol, polycarboxylic acid, cellulose compounds (hydroxyethyl cellulose, carboxymethyl cellulose, etc.), and polyvinylpyrrolidone. In addition, the addition amount of the dispersion stabilizer is preferably 1 to 10 parts by mass per 100 parts by mass of the monomer containing the monomer for seed particle production.

1-2. Method for producing resin particles derived from polymerizable vinyl monomers

In the present invention, a known polymerizable vinyl monomer can be widely used as the polymerizable vinyl monomer. Among these, it is preferred that it is at least one monomer selected from the group consisting of a monofunctional (meth)acrylic acid ester monomer, a polyfunctional (meth)acrylic acid ester monomer, a monofunctional styrene monomer, and a polyfunctional styrene monomer.

As the monofunctional (meth)acrylic acid ester monomer, a known monofunctional (meth)acrylic acid ester monomer commonly used in this field may be widely used. For example, acrylic acid esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, and 2-ethylhexyl acrylate; Methyl methacrylate (methyl methacrylate; MMA), ethyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate , 2-methoxyethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, diethylaminoethyl methacrylate, trifluoroethyl methacrylate, heptadecafluorodecyl methacrylate, methacrylate Methacrylic acid esters such as n-butyl acrylate, t-butyl methacrylate, and 2-ethylhexyl methacrylate, and (meth)acrylic acid esters having a hydroxyl group at the terminal and a long-chain alkylene oxide moiety can be used. These monofunctional (meth)acrylic acid ester monomers can be used either individually or in combination of two or more. Among these monofunctional (meth)acrylic acid ester monomers, methyl methacrylate (methyl methacrylate; MMA), n-butyl methacrylate, and a hydroxyl group at the terminal from the viewpoint of affinity with the shell portion made of the π-conjugated polymer compound. A (meth)acrylic acid ester having a long chain alkylene oxide moiety is preferred.

As the polyfunctional (meth)acrylic acid ester monomer. Known polyfunctional (meth)acrylic acid ester monomers commonly used in this field can be widely used. For example, trimethylolpropane triacrylate, ethylene glycol dimethacrylate (ethylene glycol dimethacrylate), diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, decaethylene glycol dimethacrylate, dimethacrylate Pentadecaethylene glycol acrylate, pentaconthaconthahexanethylene glycol dimethacrylate, 1,3-butylene dimethacrylate, allyl methacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, dimethacrylate Diethylene glycol phthalate acrylate, etc. can be used. These polyfunctional (meth)acrylic acid ester monomers can be used either individually or in combination of two or more. Among these polyfunctional (meth)acrylic acid ester monomers, ethylene glycol dimethacrylate (ethylene glycol dimethacrylate) is preferable from the viewpoint of affinity with the shell portion made of the ?-conjugated polymer compound.

As the monofunctional styrene-based monomer, a known monofunctional styrene-based monomer commonly used in this field may be widely used. For example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, and the like can be used. These monofunctional styrene-based monomers can be used individually or in combination of two or more. Among these monofunctional styrene-based monomers, styrene is preferred from the viewpoint of affinity with a shell portion made of a ?-conjugated polymer compound.

As the polyfunctional styrene monomer, a known polyfunctional styrene monomer commonly used in this field may be widely used. For example, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof can be used. These polyfunctional styrene-based monomers can be used alone or in combination of two or more. Among these polyfunctional styrene-based monomers, divinylbenzene is preferred from the viewpoint of affinity with the shell portion made of a ?-conjugated polymer compound.

As a polymerization method for producing resin particles derived from a polymerizable vinyl monomer, a polymerization method commonly used in this field can be widely used. For example, methods such as bulk polymerization, emulsion polymerization, soap-free emulsion polymerization, seed polymerization, and suspension polymerization can be mentioned.

In the present invention, the resin particles derived from the polymerizable vinyl-based monomer are preferably produced by seed polymerization, since variations in the particle diameter of the produced resin particles can be suppressed. The general method of the seed polymerization method is described below.

First, seed particles are added to an aqueous emulsion composed of a polymerizable vinylic monomer and an aqueous medium. Examples of the aqueous medium include water or a mixed solvent of water and an organic solvent (eg, a hydrophilic organic solvent such as a lower alcohol having 5 or less carbon atoms).

It is preferable that the aqueous medium contains a surfactant. As the surfactant, anionic, cationic, nonionic, and amphoteric surfactants can all be used.

Examples of anionic surfactants include fatty acid oils such as sodium oleate and potassium castor oil, alkyl sulfate ester salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkyl Naphthalene sulfonic acid salt, alkanesulfonic acid salt, dialkyl sulfosuccinate salt such as sodium dioctyl sulfosuccinate, alkenyl succinate (di potassium salt, etc.), alkyl phosphate ester salt, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkylphenyl ether Sulfate ester salt, polyoxyethylene alkyl ether sulfate, such as polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene alkyl sulfate ester salt, etc. are mentioned.

Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.

As a nonionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, etc. can be used.

Examples of amphoteric ionic surfactants include lauryl dimethylamine oxide, phosphate ester, and phosphorous acid ester surfactants.

The surfactant may be used alone or in combination of two or more. Among the above surfactants, anionic surfactants are preferred from the viewpoint of dispersion stability during polymerization.

An aqueous emulsion can be prepared by a known method. For example, an aqueous emulsion can be obtained by adding a polymerizable vinylic monomer to an aqueous medium and dispersing it with a fine emulsifier such as a homogenizer, an ultrasonic treatment device, or a nanomizer. The particle diameter of the droplets of the polymerizable vinylic monomer in the obtained aqueous emulsion is preferably smaller than the seed particles because the polymerizable vinylic monomer is efficiently absorbed by the seed particles.

Seed particles can be added directly to the aqueous emulsion. Further, a dispersion (dispersion containing seed particles) in which seed particles are dispersed in an aqueous medium may be added to the aqueous emulsion while stirring.

When the seed particles are added directly to the aqueous emulsion, after the seed particles are added to the aqueous emulsion, the polymerizable vinylic monomer is absorbed in the seed particles. This absorption can usually be carried out by stirring the aqueous emulsion after the seed particles are added at room temperature (20°C to 25°C) for 1 to 12 hours. In addition, by heating the aqueous emulsion to about 30 to 50°C, absorption can be promoted.

The seed particles swell by absorbing the polymerizable vinylic monomer. The mixing ratio of the polymerizable vinylic monomer and the seed particles is preferably in the range of 5 to 300 parts by mass, and more preferably in the range of 100 to 250 parts by mass with respect to 1 part by mass of the seed particles. When the mixing ratio of the polymerizable vinylic monomer and the seed particles is within the above range, the efficiency of the polymerization reaction in the aqueous emulsion is improved. On the other hand, the termination of absorption of the polymerizable vinyl-based monomer by the seed particles (completion of the polymerization reaction) can be determined by confirming the enlargement of the particle diameter by observation of an optical microscope.

A polymerization initiator can be added to the aqueous emulsion. As a polymerization initiator, for example, benzoyl peroxide, lauroyl peroxide, orthochloro benzoyl peroxide, orthomethoxy benzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-ethylhexano Organic peroxides such as acid and di-t-butyl peroxide; Azobisisobutyronitrile (2,2'-azobis(2-methylpropionitrile)), 1,1'-azobiscyclohexanecarbonitrile, 2,2'-azobis(2,4-dimethylvale Azo compounds, such as ronitrile), etc. are mentioned. It is preferable to use a polymerization initiator in the range of 0.1-1 mass parts with respect to 100 mass parts of polymerizable vinyl-type monomers.

Subsequently, by polymerizing the polymerizable vinyl-based monomer absorbed by the seed particles, resin particles derived from the polymerizable vinyl-based monomer are obtained. The polymerization temperature can be appropriately selected according to the type of the polymerizable vinyl monomer and polymerization initiator. The polymerization temperature is preferably 25 to 110°C, more preferably 50 to 100°C. The polymerization reaction is preferably carried out after the seed particles have completely absorbed the monomer, optionally the polymerization initiator, and then heated up. The polymerization time is preferably 1 to 12 hours. After completion of polymerization, if necessary, the resin particles derived from the polymerizable vinyl-based monomer are centrifuged to remove the aqueous medium, washed with water or water and a solvent, and dried and isolated.

In the above polymerization step, in order to improve the dispersion stability of the resin particles derived from the polymerizable vinyl-based monomer, a dispersion stabilizer may be added. Examples of the dispersion stabilizer include polyvinyl alcohol, polycarboxylic acid, cellulose compounds (hydroxyethyl cellulose, carboxymethyl cellulose, etc.), and polyvinylpyrrolidone. Further, inorganic water-soluble polymer compounds such as sodium tripolyphosphate can also be used in combination. Among these dispersion stabilizers, polyvinyl alcohol and polyvinylpyrrolidone are preferred. The amount of the dispersion stabilizer added is preferably 1 to 10 parts by mass per 100 parts by mass of the polymerizable vinylic monomer.

In addition, in order to suppress the generation of emulsified particles in the aqueous system in the polymerization step, water-soluble polymerization inhibitors such as nitrite compounds, sulfite compounds, hydroquinone compounds, ascorbic acid compounds, water-soluble vitamin B compounds, citric compounds, and polyphenol compounds. You can use

2. Method for producing colored organic resin particles

The manufacturing method of the colored organic resin particles of the present invention includes (1) coating the surface of a core portion made of resin particles obtained by polymerizing a polymerizable vinylic monomer in an aqueous medium with a shell portion made of a polymer compound having conjugated π electrons. , The process of forming the core-shell structure, (2) the process of dispersing the core-shell structure formed in the step (1) in an alkaline aqueous solution, and (3) the core-shell structure dispersed in the aqueous alkali solution in the step (2) is alkaline. The step of separating from the aqueous solution and washing is included in this order.

Hereinafter, steps (1) to (3) will be described.

2-1. Process (1)

Step (1) is a step of forming a core-shell structure by covering the surface of a core portion made of resin particles obtained by polymerizing a polymerizable vinyl-based monomer in an aqueous medium with a shell portion made of a polymer compound having conjugated π electrons.

The core shell structure in step (1) contains resin particles derived from a polymerizable vinyl-based monomer obtained by the seed polymerization method described above, etc., in an aqueous medium containing a persulfate, optionally containing a nitrogen-containing heteroaromatic compound as a monomer. The amount is added and obtained by oxidation polymerization. The nitrogen-containing heteroaromatic compound is a compound composed of a polymer colored black by oxidation polymerization.

<Nitrogen-containing aromatic compound>

Examples of the nitrogen-containing aromatic compounds as monomers include nitrogen-containing heterocyclic aromatic compounds such as pyrrole, indole, imidazole, pyridine, pyrimidine, and pyrazine, and their alkyl and halogen substituents (e.g., fluoro group, chloro Group, a substituent with a halogen group such as a bromo group), a nitrile substituent, an alkoxy substituent, a hydroxy substituent, a methoxy substituent, and a derivative such as a carboxy substituent. These monomers can be used alone to form a homopolymer. In addition, two or more types of these monomers may be used in combination to form a copolymer. Examples of the alkyl substituent include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n- Decyl group, etc. are mentioned.

As the π-conjugated polymer compound forming the shell portion of the colored organic resin particles of the present invention, a more uniform shell portion is easily formed, and a color having a volume resistivity of 1×10 ^{3 to} 1×10 ⁸ (Ω·cm) From the viewpoint of obtaining organic resin particles, a polymer of a pyrrole and a polymer of a derivative of a pyrrole are preferred.

The derivatives of pyrrole include 3-methylpyrrole, 3-butylpyrrole, 3-octylpyrrole, 3-decylpyrrole, 3,4-dimethylpyrrole, 3,4-dibutylpyrrole, 3-hydroxypyrrole, 3 -Methyl-4-hydroxypyrrole, 3-methoxypyrrole, 3-ethoxypyrrole, 3-octoxypyrrole, 3-carboxylpyrrole, 3-methyl-4-carboxylpyrrole, and the like. Among these derivatives of pyrrole, 3,4-dimethylpyrrole is preferred.

The addition amount of the nitrogen-containing aromatic compound as a monomer is preferably 1 to 30 parts by mass, more preferably 3 to 20 parts by mass with respect to 100 parts by mass of the resin particles derived from the polymerizable vinyl-based monomer.

When it is within the above range, the entire surface of the resin particles derived from the polymerizable vinyl-based monomer is uniformly coated with a polymer of a nitrogen-containing aromatic compound, so that resin particles having a desired blackness can be obtained.

<Persulfate>

Persulfate is a compound that acts as an oxidizing agent for nitrogen-containing aromatic compounds. Examples of the persulfate salt include alkali metal persulfate salts such as lithium persulfate, potassium persulfate and sodium persulfate; Magnesium persulfate, calcium persulfate, ammonium persulfate, etc. are mentioned. Among these persulfates, ammonium persulfate is preferable.

The amount of persulfate added is preferably 1 to 10 parts by mass, more preferably 1 to 5 parts by mass, based on 1 part by mass of the nitrogen-containing aromatic compound.

When it is within the above range, the entire surface of the resin particles derived from the polymerizable vinyl-based monomer is uniformly coated with the polymer of the nitrogen-containing aromatic compound, so that the desired blackness can be imparted to the resin particles.

<aqueous medium>

Persulfate is added to the aqueous medium and is used to dissolve nitrogen-containing aromatic compounds as an aqueous medium of a predetermined pH. As the aqueous medium, a known aqueous medium can be widely used. For example, water or alcohol, such as water, methanol, ethanol, n-propanol, isopropanol (isopropyl alcohol), n-butanol, t-butanol, diethyl ether, isopropyl ether, n-butyl ether, methyl And mixed media of ethers such as cellosolve and tetrahydrofuran, ketones such as acetone, methyl ethyl ketone, and diethyl ketone.

It is preferable that the aqueous medium to which persulfate is added has a pH of 3-10.

When it is within the above range, the entire surface of the resin particles derived from the polymerizable vinyl-based monomer is uniformly coated with the polymer of the nitrogen-containing aromatic compound, so that the desired blackness can be imparted to the resin particles.

<Surfactant>

Surfactants can be added to the aqueous medium. As the surfactant, any of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants can be used.

Examples of anionic surfactants include fatty acid oils such as sodium oleate and potassium castor oil, alkyl sulfate ester salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkyl Naphthalene sulfonic acid salt, alkanesulfonic acid salt, dialkyl sulfosuccinate salt such as sodium dioctyl sulfosuccinate, alkenyl succinate (di potassium salt, etc.), alkyl phosphate ester salt, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkylphenyl ether Sulfate ester salt, polyoxyethylene alkyl ether sulfate, such as polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene alkyl sulfate ester salt, etc. are mentioned.

Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.

As a nonionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, etc. can be used.

Examples of amphoteric ionic surfactants include lauryl dimethylamine oxide, phosphate ester, and phosphorous acid ester surfactants.

The surfactant may be used alone or in combination of two or more. Among the above surfactants, anionic surfactants are preferred from the viewpoint of dispersion stability during polymerization. The amount of the surfactant to be added is preferably 0.0001 to 1 part by weight based on 100 parts by weight of the aqueous medium.

In addition to surfactants, dispersion stabilizers may be added to the aqueous medium. As a dispersion stabilizer, polyacrylic acid, polymethacrylic acid, polyvinylpyrrolidone, hydroxypropyl cellulose (HPC), etc. are mentioned, for example. The dispersion stabilizer can be used in combination with the above-described surfactant.

<Oxidation polymerization>

A core-shell structure in which the surface of the core portion made of resin particles derived from a polymerizable vinyl monomer is covered with a shell portion made of a π-conjugated polymer compound (a coating layer containing a polymer of a nitrogen-containing aromatic compound) is obtained, for example, by the following method. I can.

That is, an emulsion (suspension) and a nitrogen-containing aromatic compound in which resin particles derived from polymerizable vinylic monomers obtained by the above-described seed polymerization method or the like are dispersed are added to an aqueous medium containing persulfate to obtain a mixture. Subsequently, the mixture is stirred at a temperature of -20 to 40° C. for 0.5 to 10 hours to obtain a core-shell structure.

The core shell structure obtained by the above method is separated and cleaned. Specifically, the core-shell structure obtained by the above-described method is separated by means such as filtration or centrifugation, and washed with water or a solvent. The separated and cleaned core shell structure is isolated as a hydrous cake. As water, ion water, distilled water, etc. are mentioned, for example. As a solvent, toluene, benzene, xylene, etc. are mentioned, for example.

2-2. Process (2)

Step (2) is a step of dispersing the core shell structure formed in step (1) in an alkaline aqueous solution. This step is a step of removing dopants (anions such as sulfate ions) in the core shell structure formed in step (1) by performing an undoping treatment.

<Dedoping treatment>

The core-shell structure isolated by the hydrous cake is dispersed in an alkaline aqueous solution, stirred for 1 hour or more, and subjected to undoping treatment (alkali treatment) to release (remove) anions such as sulfate ions, which are dopants in the core-shell structure. I can.

The alkaline aqueous solution can be prepared from a common base such as sodium hydroxide and ammonia. The pH of the alkaline aqueous solution is preferably from 7.5 to 14, more preferably from 8 to 13.5, still more preferably from 8.5 to 13, and particularly preferably from 9 to 12.5 from the viewpoint of the time efficiency of the undoping treatment.

The stirring time is usually 1 hour or more and 15 hours or less, preferably 2 hours or more and 14 hours or less, more preferably 3 hours or more and 13 hours or less, even more preferably, since anions such as sulfate ions, which are dopants, can be released. It is preferably 4 hours or more and 12.5 hours or less, particularly preferably 4.5 hours or more and 12 hours or less.

The temperature at the time of stirring is usually 0 to 100°C, preferably 10 to 95°C, more preferably 20 to since the separation of anions such as dopant sulfate ions is accelerated and dedoping treatment in a short time is possible. 90°C, more preferably 30 to 85°C, particularly preferably 40 to 80°C.

2-3. Process (3)

Step (3) is a step of separating and washing the core shell structure dispersed in the aqueous alkali solution in the step (2) from the aqueous alkaline solution.

In the step (2), the core shell structure dispersed in the aqueous alkali solution is separated from the aqueous alkaline solution by filtration or centrifugation, and washed with water.

As the water, for example, natural water, purified water, distilled water, ion-exchanged water, pure water, and the like can be used.

The separated and washed core shell structure is then dried by a known method such as an oven, a vacuum (reduced pressure) oven, and a stirring (vacuum) dryer, and isolated as a powder. The powder isolated in this way is the colored organic resin particles of the present invention.

Example

Hereinafter, the present invention will be specifically described based on Examples, but the present invention is not limited thereto.

The ion-exchanged water used in Examples and Comparative Examples is water that has been deionized with an ion-exchange resin, and has a conductivity of 1.0 µS/cm or less.

First, a measurement method and a calculation method in Examples and Comparative Examples are described.

(Average particle diameter of seed particles)

The average particle diameter of the seed particles was measured with a laser diffraction scattering particle size distribution measuring device (manufactured by Beckman Coulter, Model LS230). Specifically, 0.1 g of seed particles and 10 ml of a 0.1% by weight nonionic surfactant solution were put into a test tube, and mixed for 2 seconds with a touch mixer (manufactured by Yamato Scientific Co., Ltd. "TOUCHMIXER MT-31"). Thereafter, the seed particles in the test tube were dispersed over 10 minutes using a commercially available ultrasonic cleaner (manufactured by Belvo Clear Co., Ltd., "ULTRASONIC CLEANER VS-150") to obtain a dispersion. While irradiating the dispersion with ultrasonic waves, the average particle diameter of the seed particles in the dispersion was measured with a laser diffraction scattering particle size distribution measuring device (manufactured by Beckman Coulter, type LS230). The optical model at the time of the measurement was matched to the refractive index of the produced seed particle. When one type of monomer was used for the production of seed particles, the refractive index of the homopolymer of the monomer was used as the refractive index of the seed particles. When plural kinds of monomers were used for the preparation of seed particles, the average value obtained by weighting the refractive index of the homopolymer of each monomer as the refractive index of the seed particles was used by the amount of each monomer.

(Measurement method of volume average particle diameter of resin particles derived from polymerizable vinyl monomer)

The volume average particle diameter of the resin particles derived from the polymerizable vinylic monomer was measured by Coulter Multisizer ^™ 3 (a measuring apparatus manufactured by Beckman Coulter Co., Ltd.). The measurement was performed using the aperture calibrated according to the Multisizer ^TM 3 user manual issued by Beckman Coulter.

The aperture used for measurement was appropriately selected according to the size of the resin particles to be measured. Current (aperture current) and Gain (gain) were appropriately set according to the size of the selected aperture. For example, when an aperture having a size of 50 mu m is selected, Current (aperture current) is set to -800 and Gain (gain) is set to 4.

As a sample for measurement, 0.1 g of the resin particles are contained in 10 ml of a 0.1% by weight nonionic surfactant aqueous solution. VS-150") and used as a dispersion liquid. During the measurement, the beaker was stirred slowly so that no air bubbles would enter the beaker, and the measurement was terminated when 100,000 resin particles were measured.

(Measurement method of coefficient of variation of the particle diameter based on the volume of the resin particles derived from the polymerizable vinyl monomer)

The coefficient of variation (CV value) of the volume-based particle diameter of the resin particles derived from the polymerizable vinyl monomer was calculated by the following equation.

Coefficient of variation of the particle diameter based on the volume of the resin particles derived from the polymerizable vinyl monomer = (Standard deviation of the particle size distribution based on the number of resin particles derived from the polymerizable vinyl monomer) / (Derived from the polymerizable vinyl monomer The volume average particle diameter of the resin particles) × 100

(Measurement method of volume average particle diameter of colored organic resin particles)

The volume average particle diameter of the colored organic resin particles was measured by Coulter Multisizer ^™ 3 (Measurement apparatus manufactured by Beckman Coulter Corporation). The measurement was performed using the aperture calibrated according to the Multisizer ^TM 3 user manual issued by Beckman Coulter. The aperture used for measurement was appropriately selected according to the size of the colored organic resin particles to be measured. Current (aperture current) and Gain (gain) were appropriately set according to the size of the selected aperture. For example, when an aperture having a size of 50 mu m is selected, Current (aperture current) is set to -800 and Gain (gain) is set to 4.

As a sample for measurement, 0.1 g of colored organic resin particles are contained in 10 ml of a 0.1% by weight nonionic surfactant aqueous solution, a touch mixer (manufactured by Yamato Scientific Co., Ltd., ``TOUCHMIXER MT-31'') and an ultrasonic cleaner (manufactured by Belvo Clear Co., Ltd. CLEANER VS-150") was used to disperse and used as a dispersion. During the measurement, the inside of the beaker was stirred slowly so that no air bubbles would enter, and the measurement was terminated when 100,000 colored organic resin particles were measured. The volume average particle diameter of the colored organic resin particles is an arithmetic average in the particle size distribution based on the volume of 100,000 particles.

(Measurement method of coefficient of variation of particle diameter based on volume of colored organic resin particles)

The coefficient of variation (CV value) of the particle diameter based on the volume of the colored organic resin particles was calculated by the following equation.

Coefficient of variation of the particle diameter based on the volume of the colored organic resin particles = (standard deviation of the particle size distribution based on the volume of the colored organic resin particles/volume average particle diameter of the colored organic resin particles) × 100

(Measurement method of volume resistivity of colored organic resin particles)

The volume resistivity of the colored organic resin particles was measured using a powder resistance measurement system. Specifically, by using the "powder resistance measurement system MCP-PD51 type" (manufactured by Mitsubishi Chemical Analytech Co., Ltd.), a load is applied to the colored organic resin particles filled in the probe from 0 to 20 kN in 4 kN increments. , Volume resistivity was measured for the colored organic resin particles in a state to which each load (0, 4kN, 8kN, 12kN, 16kN, and 20kN) was applied. Among the volume resistivity obtained by measuring under each load, the lowest value was taken as the volume resistivity of the colored organic resin particles.

For the colored organic resin particles, the moisture content was measured in advance by Curl Fischer moisture measurement, and it was confirmed that the moisture content was 1% by weight or less. As a resistivity meter used in the "powder resistance measurement system MCP-PD51 type", a low resistivity meter "Loresta (registered trademark)-GX MCP-T700" (manufactured by Mitsubishi Chemical Analytech Co., Ltd.) was used.

(Measurement method of sulfur element content in colored organic resin particles)

As for the content of the sulfur element in the colored organic resin particles, the peak height of the sulfur element was measured by fluorescence X-ray spectroscopy, and the amount of elements contained in the sulfur element was determined by order analysis (FP bulk method). Specifically, using a fluorescence X-ray analyzer (RIX-2100, manufactured by Rigaku Co., Ltd.), the intensity of S-Kα was measured under the following equipment conditions and qualitative element conditions, and colored organic resin particles by order analysis The content of the sulfur element in the was measured.

First, a conductive carbon double-sided tape (manufactured by Nissin EM) was affixed on a carbon sample stand (manufactured by Nissin EM). 20 mg of a sample (the colored organic resin particles produced in each Example and Comparative Example) was weighed on the affixed conductive carbon double-sided tape, and the sample was adjusted so as not to spread more than 10 mmφ. Thereafter, a PP film (polypropylene film) was coated and set in a sample case for 10 mmφ attached to the apparatus to obtain a measurement sample.

Subsequently, under the following conditions, the peak height of the sulfur element was measured, and the amount of elements contained in the sulfur element was determined by an order analysis method.

<Device conditions>

Device: RIX-2100

·X-ray district target: Rh

Analysis method: order analysis method (FP bulk method)

·Measurement diameter: 10㎜

・Spin: Yes

·Atmosphere: vacuum

·Sample form: Metal

Balance component: C8H8

・Sample protective film correction: Yes (PP film)

Smoothing: 11 points

·Flux component, dilution rate, removal of impurities: none

<Qualitative element conditions>

·S-Kα

District: Rh(30㎸-100㎃)

1st filter: OUT

・Attenuator: 1/1

Slit: Std.

Spectroscopic crystal: Ge

2Θ: 110.820deg (Measurement range: 107∼114deg)

·Detector: PC

PHA L.L.:150 U.L.:300

Step: 0.05deg

·Time: 0.4sec

(Measurement method of blackness of colored organic resin particles)

The blackness ΔE' of the colored organic resin particles is evaluated by color difference measurement based on JIS Z 8781-5 "Color display method -L*a*b* color system".

For the measurement, a color difference meter (manufactured by Konica Minolta Sensing, brand name "CR-400") and a standard white plate calibration plate (Y: 94.3, x: 0.3144, y: 0.3208) were used for standard adjustment.

Specifically, 2.5 g of colored organic resin particles are charged into a measurement container (a powder cell manufactured by Konica Minolta Sensing, brand name "CR-A50"). For arbitrary 10 points of the vertical and horizontal planes of the colored organic resin particles, the measurement area was measured as φ8 mm, and the average value was calculated from the calculated brightness L* value, color coordinate a* value, and b* value by the following equation. As ΔE' was calculated.

ΔE'=L*+｜a*｜+｜b*｜

From the obtained ΔE', blackness was evaluated according to the following criteria.

10≤ΔE'≤48: good

ΔE'<10 and 48<ΔE': poor

(Measurement method of solvent dispersibility of colored organic resin particles)

0.5 g of colored organic resin particles were each added to a beaker containing water, a beaker containing isopropanol, and a beaker containing 20 g of ethyl acetate, and the mixture was stirred at 20°C for 10 minutes with a stirrer. One minute after stirring, and after completion of stirring, the solvent dispersibility of the colored organic resin particles in water, isopropanol, and ethyl acetate was visually observed, and the solvent dispersibility was evaluated according to the following criteria. On the other hand, if it is "A" or "B" evaluation, it is evaluated that there is no problem even in practical use.

<Criteria for determining solvent dispersibility>

A: Within 1 minute after stirring, colored organic resin particles were dispersed in the state of primary particles in water, isopropanol, and ethyl acetate. Specifically, the dispersed colored organic resin particles did not dissolve with each other, and an aggregate of colored organic resin particles could not be confirmed.

B: Within 10 minutes after stirring, colored organic resin particles were dispersed in the state of primary particles in water, isopropanol, and ethyl acetate. Specifically, the dispersed colored organic resin particles did not dissolve with each other, and an aggregate of colored organic resin particles could not be confirmed.

C: Within 10 minutes after stirring, in water, isopropanol, and ethyl acetate, the colored organic resin particles were not dispersed in the state of primary particles, and a large number of aggregates of the colored organic resin particles were confirmed.

(Seed Particle Synthesis Example 1)

In a beaker, an oil phase in which 14 g of methyl methacrylate (MMA) and 0.14 g of n-octyl mercaptan were mixed as a molecular weight modifier was prepared (hereinafter, referred to as oil phase 1). On the other hand, in another beaker, 78 g of ion-exchanged water and 0.2 g of potassium persulfate were prepared as a polymerization initiator, the oil phase 1 was mixed, and soap-free polymerization was performed at 70° C. for 12 hours to obtain seed particles 1. The volume average particle diameter of the obtained seed particle 1 was 0.44 µm.

(Seed Particle Synthesis Example 2)

In a beaker, an oil phase in which 9 g of methyl methacrylate (MMA) and 0.09 g of n-octyl mercaptan were mixed as a molecular weight modifier was prepared (hereinafter, referred to as oil phase 2). On the other hand, in another beaker, 80 g of ion-exchanged water, 6.25 g of a dispersion containing seed particle 1 prepared in Seed Particle Synthesis Example 1, and 0.045 g of potassium persulfate as a polymerization initiator were prepared, and the oil phase 2 was mixed at 70°C. Seed particle 2 was obtained by performing soap-free polymerization for 12 hours. The volume average particle diameter of the obtained seed particle 2 was 11 µm.

(Seed Particle Synthesis Example 3)

In a beaker, an oil phase in which 5 g of methyl methacrylate (MMA) and 0.05 g of n-octyl mercaptan were mixed as a molecular weight modifier was prepared (hereinafter referred to as oil phase 3). On the other hand, in another beaker, an aqueous phase obtained by mixing 20 g of ion-exchanged water and 0.05 g of sodium dioctyl sulfosuccinate as a surfactant was prepared. The obtained aqueous phase and the oil phase 3 were mixed, and treated at 8000 rpm for 10 minutes with a TK homomixer (manufactured by Primix Corporation) to obtain an aqueous emulsion.

To the obtained aqueous emulsion, 2.5 g of a dispersion containing seed particles 2 prepared in the seed particle synthesis example 2 was added while stirring. After stirring for 1 hour, 0.2 g of polyvinylpyrrolidone as a dispersion stabilizer was dissolved in 10 g of ion-exchanged water, and a solution was added, followed by seed polymerization at 55°C for 12 hours to obtain seed particles 3. The volume average particle diameter of the obtained seed particle 3 was 2.82 µm. This particle was made into seed particle 3.

(Preparation Example 1 of Resin Particles Derived from Polymerizable Vinyl Monomer)

In a 5L reactor equipped with a stirrer and thermometer, as a polymerizable vinylic monomer, 70 g of methyl methacrylate (MMA), 300 g of ethylene glycol dimethacrylate (EGDMA), and 2,2'-azobis ( 2-methylpropionitrile) 0.6 g and benzoyl peroxide 0.4 g were mixed. The obtained mixture was mixed with a solution in which 0.5 g of sodium dioctyl sulfosuccinate was added as a surfactant to 100 g of ion-exchanged water, and treated at 8000 rpm for 10 minutes with a TK homomixer (manufactured by Primix) to obtain an aqueous emulsion. To this aqueous emulsion, 17 g of a dispersion containing seed particles 1 was added while stirring.

After stirring was continued for 3 hours, 200 g of an aqueous solution in which 0.03 g of polyvinyl alcohol was dissolved as a dispersion stabilizer was put into a reactor, polymerization was performed at 60°C for 6 hours while stirring, and then further reacted at 105°C for 3 hours. After filtering the obtained resin particles, they were washed with 12 times the amount of ion-exchanged water and dried in an oven at 60°C to obtain resin particles A derived from polymerizable vinyl monomers. The volume average particle diameter of the resin particles A was 1.5 µm, and the coefficient of variation of the particle diameter on a volume basis was 12.2%.

(Preparation Example 2 of Resin Particles Derived from Polymerizable Vinyl Monomer)

In the same manner as in Preparation Example 1 of the resin particles derived from the polymerizable vinyl-based monomer, except for using 5 g of the dispersion containing the seed particles 2 instead of 17 g of the dispersion containing the seed particles 1, Resin particle B was obtained. The volume average particle diameter of the resin particles B was 5.89 µm, and the coefficient of variation of the particle diameter on a volume basis was 10.7%.

(Production Example 3 of Resin Particles Derived from Polymerizable Vinyl Monomer)

In the same manner as in Preparation Example 1 of the resin particles derived from the polymerizable vinyl-based monomer, except for using the dispersion solution containing the seed particles 3 instead of 17 g of the dispersion containing the seed particles 1 Resin particle C was obtained. The volume average particle diameter of the resin particles C was 12.2 µm, and the coefficient of variation of the particle diameter on a volume basis was 9.1%.

(Example 1)

To a solution in which 40 g of ammonium persulfate was dissolved in 600 g of ion-exchanged water, a suspension in which 60 g of resin particles A were dispersed in 60 g of isopropanol was added and stirred. This suspension was cooled to 15°C, 10 g of pyrrole was added, and the mixture was stirred at 15°C or lower for 3 hours to perform polymerization. The obtained dispersion was suction filtered to obtain a solid content. The solid content was taken out and washed with ion-exchanged water. The obtained hydrous cake was redispersed in 600 g of ion-exchanged water, and treated with a TK homomixer (manufactured by Primix Co., Ltd.) at 5000 rpm for 10 minutes. 15 g of sodium hydroxide was added to the obtained aqueous solution and stirred. When the pH of the aqueous solution after stirring was measured with a pH meter (manufactured by Horiba Corporation, D21), the pH was 10. Then, it stirred at 40 degreeC for 12 hours further. The obtained dispersion was filtered, separated from an aqueous sodium hydroxide solution, and washed with ion water. Then, the separated particles were dried at 60° C. for 12 hours using a vacuum dryer to obtain black colored organic resin particles.

The volume average particle diameter of the obtained colored organic resin particles was 1.61 µm, and the coefficient of variation of the particle diameter on a volume basis was 14.8%.

(Example 2)

To a solution in which 40 g of ammonium persulfate was dissolved in 600 g of ion-exchanged water, a suspension in which 60 g of resin particles B were dispersed in 60 g of isopropanol was added and stirred. This suspension was cooled to 15°C, 10 g of pyrrole was added, and the mixture was stirred at 15°C or lower for 3 hours to perform polymerization. The obtained dispersion was suction filtered to obtain a solid content. The solid content was taken out and washed with ion-exchanged water. The obtained hydrous cake was redispersed in 600 g of ion-exchanged water, and treated with a TK homomixer (manufactured by Primix Co., Ltd.) at 5000 rpm for 10 minutes. 15 g of sodium hydroxide was added to the obtained aqueous solution and stirred. When the pH of the aqueous solution after stirring was measured with a pH meter (manufactured by Horiba Corporation, D21), the pH was 10. Then, it stirred at 40 degreeC for 12 hours further. The obtained dispersion was filtered, separated from an aqueous sodium hydroxide solution, and washed with ion water. Then, the separated particles were dried at 60° C. for 12 hours using a vacuum dryer to obtain black colored organic resin particles.

The volume average particle diameter of the obtained colored organic resin particles was 6.01 µm, and the coefficient of variation of the particle diameter on a volume basis was 8.1%.

(Example 3)

To a solution in which 40 g of ammonium persulfate was dissolved in 600 g of ion-exchanged water, a suspension in which 60 g of resin particles C were dispersed in 60 g of isopropanol was added and stirred. This suspension was cooled to 15°C, 10 g of pyrrole was added, and the mixture was stirred at 15°C or lower for 3 hours to perform polymerization. The obtained dispersion was suction filtered to obtain a solid content. The solid content was taken out and washed with ion-exchanged water. The obtained hydrous cake was redispersed in 600 g of ion-exchanged water, and treated with a TK homomixer (manufactured by Primix Co., Ltd.) at 5000 rpm for 10 minutes. To the obtained aqueous solution, 10 g of sodium hydroxide was added and stirred. When the pH of the aqueous solution after stirring was measured with a pH meter (manufactured by Horiba Corporation, D21), the pH was 9. Then, it stirred at 40 degreeC for 12 hours further. The obtained dispersion was filtered, separated from an aqueous sodium hydroxide solution, and washed with ion water. Then, the separated particles were dried at 60° C. for 12 hours using a vacuum dryer to obtain black colored organic resin particles.

The volume average particle diameter of the obtained colored organic resin particles was 12.3 µm, and the coefficient of variation of the particle diameter on a volume basis was 8.9%.

(Example 4)

To a solution in which 40 g of ammonium persulfate was dissolved in 600 g of ion-exchanged water, a suspension in which 60 g of resin particles A were dispersed in 60 g of isopropanol was added and stirred. This suspension was cooled to 15°C, 10 g of pyrrole was added, and the mixture was stirred at 15°C or lower for 3 hours to perform polymerization. The obtained dispersion was suction filtered to obtain a solid content. The solid content was taken out and washed with ion-exchanged water. The obtained hydrous cake was redispersed in 600 g of ion-exchanged water, and treated with a TK homomixer (manufactured by Primix Co., Ltd.) at 5000 rpm for 10 minutes. 15 g of sodium hydroxide was added to the obtained aqueous solution and stirred. When the pH of the aqueous solution after stirring was measured with a pH meter (manufactured by Horiba Corporation, D21), the pH was 10. Then, it stirred at 40 degreeC for 6 hours further. The obtained dispersion was filtered, separated from an aqueous sodium hydroxide solution, and washed with ion water. Then, the separated particles were dried at 60° C. for 12 hours using a vacuum dryer to obtain black colored organic resin particles.

The volume average particle diameter of the obtained colored organic resin particles was 1.61 µm, and the coefficient of variation of the particle diameter based on the volume was 13.4%.

(Comparative Example 1)

To a solution in which 40 g of ammonium persulfate was dissolved in 600 g of ion-exchanged water, a suspension in which 60 g of resin particles A were dispersed in 60 g of isopropanol was added and stirred. This suspension was cooled to 15°C, 10 g of pyrrole was added, and the mixture was stirred at 15°C or lower for 3 hours to perform polymerization. The obtained dispersion was suction filtered to obtain a solid content. The solid content was taken out and washed with ion-exchanged water. Thereafter, the washed particles were dried at 60° C. for 12 hours using a vacuum dryer to obtain black colored organic resin particles.

The volume average particle diameter of the obtained colored organic resin particles was 1.61 µm, and the coefficient of variation of the particle diameter on a volume basis was 14.2%.

(Comparative Example 2)

A colored organic resin particle was obtained in the same manner as in Comparative Example 1 except that 20 g of ammonium persulfate was used and 3 g of pyrrole was added.

The volume average particle diameter of the obtained colored organic resin particles was 1.61 µm, and the coefficient of variation of the particle diameter on a volume basis was 14.3%.

(evaluation)

For the colored organic resin particles obtained in Examples 1 to 4 and Comparative Examples 1 to 2, the content of the sulfur element, volume resistivity, blackness, and solvent dispersibility were measured. Table 1 shows these results.

(result)

Since the colored organic resin particles obtained in Examples 1 to 4 were subjected to undoping treatment by adding sodium hydroxide, a result was obtained that the content of the sulfur element was significantly less than that of the colored organic resin particles obtained in Comparative Examples 1 and 2. Therefore, the colored organic resin particles obtained in Examples 1 to 4 have a volume resistivity in the range of 1×10 ^{3 to} 1×10 ⁸ (Ω·cm) by decreasing the amount of sulfate ions as a dopant and decreasing the conductivity. Showed.

As described above, in the colored organic resin particles obtained in Examples 1 to 4, sulfate ions as a dopant were released from the π-conjugated polymer compound that contributes to the expression of conductivity by undoping, and a hydroxyl group in the aqueous alkali solution was introduced instead. As, it is thought that the result of being dispersed in the state of primary particles in a solvent such as water, isopropanol, and ethyl acetate was obtained due to a decrease in electrical conductivity.

The colored organic resin particles obtained in Comparative Example 1 were not subjected to undoping treatment, and the sulfate ions, which are dopants, were not released from the π-conjugated polymer compound that contributes to the development of conductivity, and the conductivity was not decreased. It is thought that a low value of ² (Ω·cm) was displayed. As a result, it is considered that the solvent dispersibility was poor, and the colored organic resin particles formed an aggregate.

The colored organic resin particles obtained in Comparative Example 2 had less amounts of ammonium persulfate and pyrrole added than in Comparative Example 1, and were not subjected to undoping treatment. For this reason, it is thought that the coating amount of the π-conjugated polymer compound was small, the value of the blackness (ΔE') was 50, and white color appeared strong. In addition, the colored organic resin particles obtained in Comparative Example 2 exhibited a high volume resistivity of 1.2×10 ⁷ (Ω·cm) because the coating amount of the π-conjugated polymer compound contributing to the development of conductivity was small, but a hydroxyl group was present. Since it does not, it is thought that the result of solvent dispersibility "C" was obtained.

Claims (7)

As colored organic resin particles composed of a core portion made of resin particles derived from a polymerizable vinyl monomer, and a shell portion made of a π-conjugated polymer compound on the surface of the core portion,
The volume resistivity is 1×10 ³ ∼ 1×10 ⁸ (Ω·cm), and
In the color difference measurement based on JIS Z 8781-5 "Color Display Method-L*a*b* Color System", the following equation:
10≤ΔE'=L*+｜a*｜+｜b*｜≤48
(In the formula, ΔE' represents blackness, L* represents brightness, and a* and b* represent color coordinates)
Colored organic resin particles satisfying the relational expression represented by. The method of claim 1,
Coloring wherein the polymerizable vinyl monomer is at least one monomer selected from the group consisting of a monofunctional (meth)acrylic acid ester monomer, a polyfunctional (meth)acrylic acid ester monomer, a monofunctional styrene monomer, and a polyfunctional styrene monomer Organic resin particles. The method according to claim 1 or 2,
The ?-conjugated polymer compound is a polymer of a nitrogen-containing heteroaromatic compound. As the colored organic resin particles according to any one of claims 1 to 3,
The colored organic resin particles in which the content of the sulfur element in the colored organic resin particles measured by fluorescence X-ray analysis is 0.12% by mass or less. As the colored organic resin particles according to any one of claims 1 to 4,
The colored organic resin particles, wherein the colored organic resin particles have a volume average particle diameter of 1 to 100 µm, and a coefficient of variation of the volume-based particle diameter of the colored organic resin particles is 20% or less. The method according to any one of claims 1 to 5,
Colored organic resin particles used as a light control device or a spacer of a light control film. As a method for producing the colored organic resin particles according to any one of claims 1 to 6,
A step of forming a core shell structure by covering the surface of a core portion made of resin particles obtained by polymerizing a polymerizable vinylic monomer in an aqueous medium with a shell portion made of a polymer compound having conjugated π electrons;
A step of dispersing the core shell structure in an alkaline aqueous solution, and
A method for producing colored organic resin particles comprising a step of separating and washing the core shell structure in the alkaline aqueous solution.