JP2003212913A - Method for producing colored resin particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain colored resin particles excellent in the dispersedness of a colorant. <P>SOLUTION: The method for producing colored resin particles is one comprising suspending a polymerizable monomer composition prepared by dispersing at least a colorant in a polymerizable monomer in an aqueous dispersion medium containing a stabilizer, wherein the colorant has been dispersed in the polymerizable monomer in the presence of a colorant dispersing agent and a preventive against the transfer of the colorant to the water phase. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing colored resin particles.

[0002]

2. Description of the Related Art Colored resin particles obtained by dispersing and mixing various pigments typified by carbon black into various resin materials are used, for example, to impart a design property to paints and resin moldings. It is widely used as an additive, a raw material for an electrophotographic toner, and display particles for an electrophoretic display device. Examples of the method for producing such colored resin particles include a melt-kneading method in which a pigment component is blended with a resin material and melt-kneaded and then pulverized to obtain colored resin particles, and a pigment component is dispersed and blended in a polymerizable monomer to prepare an aqueous system. A suspension polymerization method and the like in which colored resin particles are produced by carrying out suspension polymerization in a medium are known.

Among them, the suspension polymerization method has been widely used in recent years because particles having a relatively uniform particle size distribution and a spherical shape can be obtained. For example, Patent No. 28
Japanese Patent No. 72876 proposes a method of obtaining particles having a uniform particle size by suspension polymerization in the presence of a dispersant comprising magnesium pyrophosphate and a diester of phosphite or a partial ester of phosphoric acid. However, many colorants such as carbon black have a weak affinity for other substances, for example, water, an organic solvent, or an organic polymer as compared with the cohesive force between particles, and are likely to cause secondary coagulation.
Therefore, when carrying out the suspension polymerization as described above, how to uniformly disperse the colorant becomes a problem.

In JP-A-60-254050, a phenol / terpene copolymer is added for the purpose of improving the stability of a suspension polymerization system when additives such as carbon black and a charge control agent are added. A method of doing so is disclosed. Further, JP-A-7-199536 discloses that the dispersibility of a colorant is improved by adding a monomer or polymer having a polar functional group in the oil phase, particularly sodium styrenesulfonate and p-carboxystyrene. A method is disclosed.

By adding these substances, the stability of suspension polymerization can be improved or the colorant can be dispersed in the polymerizable monomer.
Although it is improved as compared with that without addition, it is still not sufficiently stable, and aggregation immediately starts. Therefore, the dispersion stability in the polymerizable monomer is insufficient, the dispersion stability during suspension and during the polymerization is poor, and the particles are localized or aggregated. Is not only non-uniform, but also causes a decrease in the uniformity of the amount of the colorant present among the individual particles. Further, the residual ratio of the colorant in the colored resin particles decreases because the colorant migrates to the aqueous phase during suspension and polymerization.
It also causes problems such as deterioration of coloring power, loss of raw materials, pollution of colored resin particles by free colorant transferred to the aqueous phase, and pollution of waste water. This problem was particularly remarkable in the case of a coloring agent having a hydrophilic group such as carbon black.

In order to improve the dispersibility of carbon black, Japanese Patent Publication No. 2996785 reports a technique of using a coordination compound having a specific structure containing titanium as a central metal as a dispersion aid. However, even with this technique, the colorant is not sufficiently dispersed, and further improvement in dispersibility has been desired. In addition, an electrophoretic display device generally has two substrates, at least one of which is transparent, arranged to face each other with a spacer interposed therebetween so as to form a closed space, and the colored particles for display are placed in the closed space. And a display panel filled with a display liquid dispersed in a dispersion medium colored in a different color tone, and an electric field is applied to this display panel to obtain a display. It becomes the display surface. By applying an electric field to the display liquid, the dispersed particles in the display liquid move to the transparent plate side, and the color of the dispersed particles appears on the surface. By applying an electric field in the opposite direction,
The dispersed particles move to the back side, and the color of the dispersion medium colored with the dye appears on the surface.

Such an electrophoretic display device obtains a desired display by controlling the direction of the electric field.
Attention is paid to it as an inexpensive display device because it has the advantages that the display liquid is a relatively low-cost material that is relatively easily available, its viewing angle is as wide as normal printed matter, power consumption is low, and it has memory properties. . Further, in order to produce an image with higher contrast, it is considered desirable to use a method of illuminating black particles suspended in a transparent medium with a backlight. On the other hand, in the field of toner and the like, black particles are generally manufactured by using a raw material such as carbon black as a colorant. However, the resin particles colored by a colorant such as carbon black obtained by the conventional technique have the above-mentioned electrical conductivity due to the non-uniformity inside the colorant particles and the adhesion of the free colorant transferred to the aqueous phase. When used as display particles for electrophoretic display devices, the long-term display stability is sufficient due to the non-uniformity of the coloring agent, which reduces the uniformity of the contrast, and the effect of the free coloring agent such as carbon black having conductivity. The thing having the excellent performance was not obtained.

[0008]

Thus, according to the present invention, a polymerizable monomer composition obtained by dispersing a colorant in at least a polymerizable monomer is suspended in an aqueous dispersion medium containing a suspension stabilizer. In producing colored resin particles by polymerizing, the colorant is characterized by being dispersed in the polymerizable monomer in the presence of a colorant dispersant and a colorant aqueous phase transfer inhibitor. A manufacturing method is provided.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method for producing colored resin particles by suspension polymerization, wherein dispersion of a colorant into a polymerizable monomer is performed by using a colorant dispersant and a colorant aqueous phase transfer inhibitor. By carrying out in the presence, the dispersion stability of the colorant in the polymerizable monomer is improved. When the dispersion treatment of the colorant in the polymerizable monomer in the presence of the colorant dispersant,
Dispersion stability of the colorant in the polymerizable monomer becomes good,
The colorant in the resulting colored resin particles is uniformly dispersed, and
The uniformity of the colorant content among the colored resin particles also becomes high.
Further, by adding a colorant water phase transfer inhibitor, it is possible to reduce the transfer of the colorant to the aqueous phase during suspension in the aqueous medium and during the polymerization process, so that the colorant in the resulting colored resin particles The residual rate becomes high, and the problem of contamination by the free colorant transferred to the aqueous dispersion medium can be suppressed. Hereinafter, the present invention will be described in more detail.

The polymerizable monomer used in the method for producing colored resin particles of the present invention is not particularly limited as long as it is suspension-polymerizable, and various vinyls generally used are used. A system monomer can be used. For example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m.
-Styrene-based monomers such as chlorostyrene and p-chlorostyrene; methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic acid Stearyl, 2-ethylhexyl acrylate, tetrahydrofurfuryl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate,
Isobutyl methacrylate, n-octyl methacrylate,
(Meth) acrylic acid ester monomers such as dodecyl methacrylate, 2-ethylhexyl methacrylate, tetrahydrofurfuryl methacrylate, stearyl methacrylate; olefinic resins such as ethylene, propylene, butylene, acrylic acid, methacrylic acid, Vinyl chloride, vinyl acetate, acrylonitrile, acrylamide, methacrylamide, N-vinylpyrrolidone and the like can be used alone or in combination of two or more.

For example, when resin particles are used as an additive for imparting a design property to paints and resin moldings, a (meth) acrylic acid ester-based monomer is used as a main component from the viewpoint of weather resistance and heat resistance. Those that do can be preferably used.

Further, for the purpose of imparting solvent resistance, as a crosslinking agent, for example, divinylbenzene, divinylnaphthalene,
Aromatic divinyl compounds such as derivatives thereof, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane triacrylate, allyl methacrylate, t-butylaminoethyl methacrylate, tetraethylene glycol dimethacrylate, 1,
A diethylenically unsaturated carboxylic acid ester such as 3-butanediol dimethacrylate, N, N-divinylaniline, divinyl ether, divinyl sulfide, all divinyl compounds of divinyl sulfonic acid and a compound having three or more vinyl groups are used together. It can also be polymerized.

When used as a toner, those containing a styrene-based monomer and / or a (meth) acrylic acid ester-based monomer as a main component can be preferably used. Further, forming a styrene- (meth) acrylic acid ester copolymer by using a styrene-based monomer and a (meth) acrylic acid ester-based monomer is advantageous in terms of low-temperature fixability and storage stability. Desirably, 50% by weight of styrene is added from the viewpoint of the thermal characteristics of the toner using the binder resin obtained.
The styrene- (meth) acrylic acid ester mixture containing the above is preferable.

When the polymerizable monomer component is thus suspension polymerized to obtain colored resin particles, another polymer such as polyester may be present in the monomer component,
Further, a known additive such as a chain transfer agent for adjusting the degree of polymerization may be appropriately added. A crosslinking agent may be used during suspension polymerization. As the colorant to be dispersed in the polymerizable monomer, pigments and dyes well known to those skilled in the art can be used.
For example, it may be an organic pigment, an inorganic pigment, or a mixture thereof.

Examples of the inorganic pigments include alumina, titanium dioxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth and various inorganic pigments. Oxide pigments, chromium oxide, cerium oxide,
Powders or particles such as red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, fine silica powder, silicon carbide, silicon nitride, boron carbide, tungsten carbide, titanium carbide, and cerium oxide can be mentioned. .

Examples of organic pigments include carbon black, Navels yellow, Naphthol yellow S,
Yellow pigments such as Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, Kiribden Orange, Permanent Orange RK, Benzidine Orange G, Indanthrene Brilliant. Orange pigments such as orange GK, permanent red 4R, resole red, pyrazolone red 4R, watching red calcium salt, lake red D, brilliant carmine 6B, eomine lake, rhodamine lake B, buzalin lake, brilliant carmine B and other red pigments, fast violet B , Purple pigments such as methyl violet lake, alkali blue lake, Victoria blue lake, phthalocyanine blue,
Examples thereof include metal-free phthalocyanine blue, phthalocyanine blue partial chloride, blue pigments such as fast sky blue and indanthrene blue BC, and green pigments such as pyrachite green lake and final yellow green G.

When a magnetic toner is to be obtained, magnetic powder such as powder of ferromagnetic metal such as iron, cobalt and nickel, powder of metal compound such as magnetite, hematite and ferrite is added. It is also possible to do so. Since these magnetic powders also act as colorants,
When obtaining a magnetic toner, these magnetic powders can be used alone or in combination with the above-mentioned pigments as a colorant.

In the present invention, the amount of the colorant compounded in the polymerizable monomer composition is not particularly limited, and depends on the kind of the colorant used and the like. Colorant 1 to 100 parts by weight of the monomer
The amount is preferably 100 parts by weight, more preferably about 3 to 50 parts by weight. When the amount of the colorant is less than 1 part by weight, the degree of coloring in the obtained colored resin particles is not sufficient, while when it exceeds 100 parts by weight, the effect of increasing the addition amount is not seen so much and the polymerizability is high. It is not preferable because the polymerization of the monomer composition may not proceed sufficiently.

In the present invention, such a colorant is dispersed in the polymerizable monomer composition in the presence of the colorant dispersant. Examples of the colorant dispersant include aluminum coupling agents such as acetoalkoxyaluminum diisopropylate. In particular,
Aluminum 9-octadecenyl acetoacetate diisopropoxide, aluminum (III) diisopropoxide ethyl acetoacetate, aluminum (I
II) Diisopropoxide stearyl acetoacetate etc. can be mentioned. Among them, aluminum (III) diisopropoxide stearyl acetoacetate represented by the following formula (1) is preferable.

[0020]

[Chemical 1]

Among the colorant dispersants used in the present invention, the aluminum-based coupling agent has many functional groups responsible for the surface treatment, and in particular, it forms a film on the particle surface of the carbon black-based organic pigment. Is more likely to spread, and is more effective than other coupling agents (for example, silane coupling agents), and is most preferable in the present invention. As the addition amount of such a colorant dispersant,
For example, with respect to 100 parts by weight of the colorant, the colorant dispersant 1 to
The amount is preferably 20 parts by weight, more preferably about 2 to 15 parts by weight. If the amount of the colorant dispersant is less than 1 part by weight, the effect of improving the dispersion stability of the colorant due to its addition and the effect of preventing the colorant from migrating to the aqueous phase during suspension and in the polymerization process cannot be sufficiently expected. If the amount is more than parts by weight, the effect is not improved so much even if the amount added is increased, which is not preferable.

In the present invention, a colorant / water phase transfer inhibitor is added to the polymerizable monomer composition during suspension polymerization. The addition of the colorant aqueous phase transfer inhibitor can more effectively suppress the transfer of the colorant to the aqueous phase during suspension and polymerization. Examples of the colorant aqueous phase transfer inhibitor include acidic organic modified phosphoric acid compounds, and examples of these acidic organic modified phosphoric acid compounds include phosphorous acid monoesters or phosphorous acid diesters, phosphoric acid monoesters, and phosphoric acid diesters. These phosphorous acid monoesters or phosphorous acid diesters, phosphoric acid monoesters, and phosphoric acid diesters are not particularly limited, but include lauryl phosphoric acid, polyoxyethylene (1) lauryl ether phosphoric acid, dipolyoxyethylene (2) alkyl ether phosphorus. Acid, dipolyoxyethylene (4) alkyl ether phosphoric acid, dipolyoxyethylene (6) alkyl ether phosphoric acid, dipolyoxyethylene (8) alkyl ether phosphoric acid, dipolyoxyether (4) nonylphenyl ether phosphoric acid , Caprolactone EO-modified phosphoric acid dimethacrylate, 2-methacryloyloxyethyl acid phosphate, and the like. Of these compounds, lauryl phosphoric acid and caprolactone EO-modified phosphoric acid dimethacrylate are preferable.

These colorant aqueous phase transfer inhibitors are added in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the polymerizable monomer composition containing the polymerizable monomer, the colorant and the colorant dispersant. It is preferably used, more preferably 0.01 to 3 parts by weight, still more preferably 0.01 to 2 parts by weight. In suspension polymerization, a suspension stabilizer can be added to the aqueous dispersion medium in order to stabilize the suspended particles.

The suspension stabilizer is not particularly limited as long as the intended resin particles can be obtained, but examples thereof include phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate and the like. , Calcium pyrophosphate, magnesium pyrophosphate, aluminum pyrophosphate, pyrophosphate such as zinc pyrophosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, colloidal Examples thereof include dispersion stabilizers of poorly water-soluble inorganic compounds such as silica. Among them, it is preferable to use an inorganic compound that can be easily dissolved and removed by adjusting the pH of the system after the completion of polymerization. For example, it is preferable to use tricalcium phosphate, magnesium pyrophosphate, calcium pyrophosphate, or colloidal silica produced by the metathesis generation method, because it is possible to obtain the target resin particles more stably. Further, a surfactant such as an anionic surfactant, a cationic surfactant, a zwitterionic surfactant, or a nonionic surfactant may be added to the aqueous dispersion medium.

Examples of the anionic surfactant include fatty acid oils such as sodium oleate and potassium castor oil, alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalene. Examples thereof include sulfonates, alkane sulfonates, dialkyl sulfosuccinates, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkylphenyl ether sulfuric acid ester salts, and polyoxyethylene alkyl sulfuric acid ester salts.

The suspension stabilizer should be used by appropriately adjusting the composition and the amount used so that the resulting colored resin particles have a predetermined particle size, for example, 1 to 100 μm, preferably 3 to 20 μm. Kimono and polymerizable monomer composition 1
0.1 to 30 parts by weight is preferable with respect to 00 parts by weight,
It is more preferably 0.5 to 20 parts by weight. The surfactant is 0.0 per 100 parts by weight of the polymerizable monomer composition.
1 to 5 parts by weight is preferable, and more preferably 0.05 to 3
Parts by weight.

As the polymerization initiator used for the polymerization,
An oil-soluble peroxide type or azo type initiator which is usually used in suspension polymerization can be used. To give an example, for example,
Benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, benzoyl orthochloroperoxide, benzoyl orthomethoxy peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, cyclohexanone peroxide, t-butyl hydroperoxide, diisopropyl Peroxide initiators such as benzene hydroperoxide, 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-triazobis (2-methyl) Butyronitrile), 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) isobutyronitrile, 4,4'-azobis (4-cyanovaleric acid), dimethyl-2,2'-azobisisobutyrate and the like. The addition amount of the polymerization initiator is preferably 0.05 to 10 parts by weight, and particularly preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the polymerizable monomer composition. Further, when used as an electrophotographic toner, an offset inhibitor, a charge control agent and the like can be added to the polymerizable monomer composition.

The offset preventive agent to be added to the polymerizable monomer composition, if necessary, is not particularly limited, but a polymer having a softening point of 80 to 180 ° C., for example,
A polyolefin having a weight average molecular weight of 1,000 to 45,000, more preferably about 2,000 to 6,000, so-called polyolefin wax can be used. For example,
As the polyolefin wax, homopolymers such as polyethylene, polypropylene and polybutylene, ethylene-
Propylene copolymer, ethylene-butene copolymer, ethylene-pentene copolymer, ethylene-3-methyl-1-
Olefin copolymers such as butene copolymers and ethylene-propylene-butene copolymers, or olefins and other monomers, for example vinyl ethers such as vinyl methyl ether, vinyl-n-butyl ether, vinyl phenyl ether, Vinyl acetates such as vinyl acetate and vinyl butyrate, vinyl fluoride, vinylidene fluoride,
Haloolefins such as tetrafluoroethylene, vinyl chloride, vinylidene chloride and tetrachloroethylene, methyl acrylate, ethyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, stearyl methacrylate, N, N- (Meth) acrylic acid esters such as dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, acrylonitrile,
Acrylic acid derivatives such as N, N-dimethylacrylamide, organic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, diethyl fumarate,
Examples thereof include copolymers with β-pinene and the like.

Further, as the anti-offset agent, besides the above-mentioned polyolefins, natural or synthetic paraffin waxes, particularly high melting point paraffin waxes having a melting point of 60 to 70 ° C., zinc salt of stearic acid, barium salt, Lead salts, cobalt salts, calcium salts and magnesium salts and magnesium salts, olefinic acid zinc salts, manganese salts, iron salts, lead salts, and palmitic acid zinc salts, cobalt salts, magnesium salts, and other fatty acid metal salts, especially carbon. Higher fatty acid salts of 17 or more, similarly higher alcohols such as myricyl alcohol, polyhydric alcohol esters such as stearic acid glyceride and palmitic acid glyceride, fatty acid esters such as myricyl stearate and myricyl palmitate, montan Partial saponification of fatty acids such as partially saponified acid Ester compounds, stearic acid, palmitic acid, higher fatty acids such as montanic acid, a mixture such as a fatty acid amide and of these such as ethylene bis-stearoyl amide is used.

Further, as the charge control agent, for example, nigrosine, monoazo dye, zinc, hexadecyl succinate, alkyl ester or alkylamide of naphthoic acid, nitrohumic acid, N, N-tetramethyldiaminebenzophenone, N, N- Examples thereof include tetramethylbenzidine, triazine, and metal salicylate complex. Incidentally, such a charge control agent, rather than added during suspension polymerization,
It is desirable to add externally to the resin particles obtained after suspension polymerization.

Next, the order of adding the polymerizable monomer composition, the colorant, the colorant dispersant, the colorant aqueous phase transfer inhibitor and the suspension stabilizer in the present invention will be described. First, in the suspension polymerization method, a colorant and other additives (for example, a polymerization initiator, a cross-linking agent, etc.) are added to and mixed with a polymerizable monomer in advance, and the resulting mixture is added to an aqueous dispersion medium. Suspended,
Colored resin particles are obtained by the polymerization treatment.

First, the colorant dispersant is either dissolved or dispersed in the polymerizable monomer in advance, and then the colorant is added to the polymerizable monomer composition, or the colorant dispersant is added to the colorant. It is preferable to add them at the same time and then to disperse the colorant using an appropriate stirring device or the like. When the colorant dispersant is added after the colorant is dispersed in the polymerizable monomer composition, sufficient dispersion stability of the colorant cannot be obtained, and therefore the colorant cannot be effectively suppressed from aggregating and migrating to an aqueous system. Not preferable.

The device for dispersing the colorant is not particularly limited, but examples thereof include media type dispersing devices such as ball mills, attritors and sand mills, and shear type such as homomixers, homogenizers and biomixers. A dispersing device and an ultrasonic dispersing device can be preferably exemplified. Next, the colorant aqueous phase transition inhibitor may be added to the polymerizable monomer composition at the same time as the dispersion treatment of the colorant in the presence of the colorant dispersant or after the dispersion of the colorant dispersant and the colorant. Is preferred.

The polymerizable monomer composition in which the colorant is dispersed by the colorant dispersant and the colorant aqueous phase transfer inhibitor is suspended in an aqueous dispersion medium. Here, in order to stabilize the suspended particles, 100 parts by weight of the polymerizable monomer composition,
It is preferable to use 100 to 1000 parts by weight of the aqueous dispersion medium. Here, the aqueous dispersion medium may be water or a mixture of water and a water-soluble solvent (eg, lower alcohol).
The suspension stabilizer is preferably added to the aqueous dispersion medium before the addition of the polymerizable monomer composition. For suspension polymerization, an aqueous dispersion medium is used, for example, 40 to 120 ° C., preferably 45 to 110 ° C.
It can be carried out by heating to the temperature. After the suspension polymerization is completed, the obtained colored resin particles are separated from the aqueous dispersion medium, washed, and dried, and if necessary, subjected to a classification step to obtain a desired particle diameter, for example, an average particle diameter of 1 to 100 μm. Preferably, colored resin particles of about 1 to 20 μm can be obtained.

The colored resin particles according to the present invention have a very good dispersion of the colorant and a high uniformity of dispersion among the particles. Therefore, it can be suitably used as an additive for imparting the design property of the paint. Also,
The colored resin particles obtained as described above, as they are,
Alternatively, if necessary, an additive such as a charge control agent for adjusting electric charge or a fluidizing agent, which is commonly used in a toner for developing an electrostatic charge, may be externally added to the toner for electrophotography. It can be preferably used. Examples of the fluidizing agent that can be used include inorganic fine particles such as colloidal silica, hydrophobic silica, hydrophobic titania, hydrophobic zirconia, and talc, and organic fine particles such as polystyrene beads and (meth) acrylic resin beads.

The colored resin particles thus obtained are
The average particle size is, for example, 2 to 20 μm, preferably 3.
It is about 5 to 15 μm, and the colorant is uniformly dispersed in each particle with a sufficient content, and the colorant content among the particles is uniform. Therefore, when an image is formed using the resin particles as a toner, the obtained image has a sufficient degree of coloring or blackening, and the charge amount between the toners is uniform and stable. It is possible to obtain a stable image without fogging. Further, the colored resin particles obtained by the present invention have high uniformity of the colorant and further have no free colorant, and thus can be suitably used as display particles for an electrophoretic display device.

When the colored resin particles of the present invention are used as display particles for an electrophoretic display device, generally two substrates, at least one of which is transparent, are arranged at a predetermined interval via a spacer to form a closed space. Then, this closed space is filled with a display liquid in which colored resin particles are dispersed in a dispersion medium to form a display panel, and an electric field is applied to this display panel to obtain a display. Although it is a display surface, the structure of the display panel is not particularly limited.

For example, the display liquid for electrophoretic display filled in the closed space is benzene, toluene, xylene, phenylxylylethane, diisopropylnaphthalene, aromatic hydrocarbons such as naphthenic hydrocarbons, hexane, dodecylbenzene, Cyclohexane, kerosene, dispersion medium of aliphatic hydrocarbons such as paraffin hydrocarbons, display particles,
Nonionic (nonionic) surfactants that can be dissolved or mixed in a dispersion medium, and ionic surfactants such as anionic surfactants, cationic surfactants, and amphoteric surfactants. However, the present invention is not limited thereto. By applying an electric field to the display liquid, the dispersed particles in the display liquid move and the color of the display particles appears. By applying an electric field in the opposite direction, the dispersed particles move and the display form can be changed.

[0039]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the following, "parts" means "parts by weight" and "%" means "% by weight" unless otherwise specified. Example 1 85 parts of methyl methacrylate, 15 parts of diethylene glycol dimethacrylate, 7 parts of carbon black (MA-100 manufactured by Mitsubishi Chemical Corporation), an aluminum-based coupling agent (acetoalkoxyaluminum diisopropylate) as a colorant dispersant; A polymerizable monomer composition was prepared using 0.4 parts of Ajinomoto Fine Techno Co., Ltd .; trade name Planeact AL-M).

The aluminum-based coupling agent of the above-mentioned polymerizable monomer composition is dissolved in a monomer mixture consisting of methyl methacrylate and diethylene glycol dimethacrylate in advance, and then carbon black is added.
It was put in a 500 ml container together with 100 g of 1.5 mm glass beads, and dispersed and mixed for 20 minutes by a tabletop sand mill. As a result of observing the dispersion mixture of the polymerizable monomer composition with an optical microscope, it was confirmed that carbon black was uniformly finely dispersed, and the dispersion stability was also good.

From the dispersion mixture of the polymerizable monomer composition, the entire amount of 1.5 mm glass beads was removed, and the ABNR
1 part (manufactured by Nippon Hydrazine Industry Co., Ltd.) and ABNV
0.5 part (manufactured by Japan Hydrazine Industry Co., Ltd.) and alkyl phosphoric acid (lauryl phosphoric acid, trade name HLP manufactured by Nikko Chemical Co., Ltd.) were added to and dissolved in the polymerizable monomer composition. Next, it was added to 400 parts by weight of water in which 0.04% sodium dodecylbenzenesulfonate and 4% magnesium pyrophosphate, which had been adjusted in advance, were dispersed, and the mixture was mixed with a homomixer (manufactured by Tokushu Kika Co., Ltd.) at 8000 rpm. 5
After stirring for a minute, a suspension was obtained. As a result of observing this suspension with an optical microscope, individual particles were uniformly colored in black, and no uncolored transparent particles were found.

The temperature of this suspension is raised under a nitrogen atmosphere while uniformly stirring the whole so that polymer particles do not settle, and the temperature is raised to 50
Polymerization was carried out at 8 ° C for 8 hours. Furthermore, the temperature was raised to 80 ° C. and the polymerization was continued for 4 hours. The particle size of this polymerization liquid was measured by Coulter Multisider II (manufactured by Coulter Co.), and as a result, the weight average particle size was 5.3 μm. Then, cool to room temperature, add hydrochloric acid to dissolve magnesium pyrophosphate as a suspension stabilizer, repeat solid-liquid separation and water washing, and then dry with a hot air dryer at 70 ° C. for 24 hours. The colored resin particles of the invention were obtained.

The amount of carbon black in the colored resin particles was measured with a thermal analyzer (high sensitivity Tg, TGA-50S manufactured by Shimadzu Corporation). The measuring method is as follows: heating at a temperature rising rate of 10 ° C./min from room temperature to 500 ° C. in a nitrogen atmosphere to completely decompose the polymer components, and then heating in an air atmosphere to 1000 ° C. at the same temperature rising rate, and in an air atmosphere The weight loss% of was defined as the amount of carbon black. As a result, the amount of carbon black in the colored resin particles was 6.4%. The residual rate of carbon black in the colored particles is 99%. As a result of observing the dispersed state of carbon black in the colored resin particles with an optical microscope, individual particles are uniformly colored black,
No clear, uncolored particles were found.

Example 2 85 parts of styrene, 15 parts of divinylbenzene, 10 parts of carbon black (MA-100 manufactured by Mitsubishi Chemical Co., Ltd.), an aluminum coupling agent (acetoalkoxyaluminum diisopropylate Ajinomoto Fine Co., Ltd.) as a colorant dispersant. A polymerizable monomer composition was prepared using 0.7 part of Techno Co., Ltd. The aluminum-based coupling agent of the polymerizable monomer composition was previously dissolved in a monomer mixture of styrene and divinylbenzene, carbon black was added, and then 1.5 mm glass beads 100 were added.
Put it in a 500 ml container with g and use a tabletop sand mill for 2
The mixture was dispersed and mixed for 0 minutes. As a result of observing this polymerizable monomer composition dispersion mixture with an optical microscope, it was confirmed that carbon black was uniformly finely dispersed, and the dispersion stability was also good.

From this polymerizable monomer composition dispersion mixture,
All 1.5 mm glass beads were removed, and 1 part of ABNR (manufactured by Japan Hydrazine Industry Co., Ltd.) and 1 part of ABNV (manufactured by Japan Hydrazine Industry Co., Ltd.) and alkyl phosphoric acid (lauryl phosphoric acid trade name HLP Nikko Chemical ( Co., Ltd.) was added to and dissolved in the polymerizable monomer composition. This polymerizable monomer composition dispersion liquid was adjusted to 0.04%
Was added to 500 parts by weight of water containing sodium dodecylbenzenesulfonate of 4% and calcium phosphate of 4%, and a homomixer (made by Tokushu Kika Co., Ltd.) was used at 5 rpm at 8000 rpm.
After stirring for a minute, a suspension was obtained. As a result of observing this suspension with an optical microscope, individual particles were uniformly colored in black, and no uncolored transparent particles were found.

This suspension was heated in a nitrogen atmosphere while uniformly stirring the whole so that polymer particles did not settle, and the temperature was raised to 80
Polymerization was carried out at 6 ° C for 6 hours. Then, the temperature was further raised to 90 ° C. and the polymerization was continued for 4 hours. The particle size of this polymerization solution was measured by Coulter Multisider II (manufactured by Coulter Co.), and as a result, the weight average particle size was 7.3 μm. Then, the mixture was cooled to room temperature, calcium phosphate was dissolved with hydrochloric acid, solid-liquid separation and washing were repeated to thoroughly wash, and then dried with a hot air dryer at 60 ° C. for 24 hours to obtain colored resin particles of the present invention.

The carbon black in the colored resin particles of the colored resin particles was measured by the same method as in Example 1. As a result, the amount of carbon black in the colored resin particles was 7.1%. The residual rate of carbon black in the colored resin particles is 100%. As a result of observing the dispersed state of carbon black of the colored resin particles with an optical microscope, the individual particles were uniformly colored black, and no uncolored transparent particles were found.

Comparative Example 1 Comparative colored resin particles were obtained by the same composition and operation as in Example 1 except that the aluminum-based coupling agent of the polymerizable monomer composition of Example 1 was not added. Each step was evaluated in the same manner as in Example 1. As a result, the dispersion state of carbon black in the dispersion mixture of the polymerizable monomer composition was observed with an optical microscope. As a result, the dispersion of carbon black was poor, and it contained coarse particles of 1 μm or more, and the dispersion stability. The secondary agglomeration was immediately caused by the absence of the agglomerates.

As a result of observing the suspension with an optical microscope, the blackness of the individual particles was not uniform, and the presence of transparent particles was recognized. The weight average particle diameter of the comparative colored resin particles obtained by polymerization was 5.8 μm. The carbon black in the colored resin particles of the comparative colored resin particles was measured in the same manner as in Example 1. As a result, the amount of the car pump rack in the colored resin particles was 2.8%. The residual rate of carbon black in the colored resin particles is 40%.

Comparative Example 2 Comparative colored resin particles were obtained with the same composition and operation as in Example 2, except that the acidic alkyl phosphoric acid in the polymerizable monomer composition of Example 1 was not used. Each step was evaluated in the same manner as in Example 1. As a result, the dispersion state of carbon black in the dispersion mixture of the polymerizable monomer composition was observed with an optical microscope. As a result, the dispersion of carbon black was poor, and it contained coarse particles of 1 μm or more and had no dispersion stability. Therefore, secondary aggregation immediately occurred.

As a result of observing the suspension with an optical microscope, the blackness of the individual particles was not uniform, and the presence of transparent particles was recognized. The weight average particle diameter of the comparative colored resin particles obtained by the polymerization was 12.1 μm. As a result of observing the dispersion of the carbon black in the particles of the comparative color resin particles, the carbon black was found to be an individual particle. The degree of blackness was uneven and the presence of transparent particles was observed. Carbon black in the colored resin particles of the comparative colored resin particles was measured in the same manner as in Example 1. As a result, the amount of carbon black in the resin particles was 3.3%. The residual ratio of carbon black in the colored resin particles is 46%.

Comparative Example 3 Comparative colored resin particles were prepared in the same composition and operation as in Example 1, except that the colorant dispersant for the polymerizable monomer composition of Example 1 was 3 parts of p-carboxystyrene. Obtained. Each step was evaluated in the same manner as in Example 1. As a result, the dispersion state of carbon black in the dispersion mixture of the polymerizable monomer composition was observed with an optical microscope. As a result, carbon black was found to be finely dispersed and coarse particles were not contained, but the dispersion stability was low. The dispersion was likely to cause secondary aggregation.

As a result of observing the suspension with an optical microscope, the blackness of the individual particles was not uniform, but the presence of transparent particles was not recognized. The weight average particle diameter of the comparative colored resin particles obtained by polymerization was 6.1 μm. The dispersion of carbon black in the particles of the comparative colored resin particles is SE
As a result of observation with an M photograph, it was in a dispersed state in which carbon black was attached to the surface of the particles and partly desorbed. Carbon black in the colored resin particles of the comparative colored resin particles was measured in the same manner as in Example 1. As a result, the amount of carbon black in the colored resin particles was 4.2%. The residual rate of carbon black in the colored resin particles is 58%.

[0054]

As described above, the dispersion of the colorant in the colored resin particles obtained by the present invention is uniform, and the uniformity of the colorant content among the colored resin particles is high. Further, the polymerizable monomer composition obtained by dispersing the colorant in the polymerizable monomer composition in the presence of the specific coupling agent as described above has a specific dispersant aqueous migration inhibitor. Under the conditions below, during the suspension in the aqueous medium and during the polymerization process, the migration of the coloring agent to the aqueous phase is small, so that the residual ratio of the coloring agent in the obtained colored resin particles is high, and the migration to the aqueous phase is free. There is also an advantage in manufacturing that the problem of contamination by the colorant is eliminated.

Continued front page    F-term (reference) 4J011 AA08 JA01 JA02 JA03 JA04                       JA05 PA03 PA04 PA07 PA08                       PA13 PA14 PA16 PA22 PA25                       PA39 PA46 PB25 PB40 PC02                 4J026 AC00 BA01 BA02 BA03 BA05                       BA10 BA20 BA25 BA27 BA31                       BA32 BA40 DB03

Claims (4)

[Claims] 1. When producing colored resin particles by suspending and polymerizing a polymerizable monomer composition in which a colorant is dispersed in at least a polymerizable monomer in an aqueous dispersion medium containing a suspension stabilizer. A method for producing colored resin particles, wherein the colorant is dispersed in the polymerizable monomer in the presence of the colorant dispersant and the colorant aqueous phase transfer inhibitor. 2. The method for producing colored resin particles according to claim 1, wherein the colorant dispersant is used in an amount of 1 to 20 parts by weight based on 100 parts by weight of the colorant. 3. The method for producing colored resin particles according to claim 1, wherein the colorant aqueous phase transfer inhibitor is used in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the polymerizable monomer composition. Method. 4. The polymerizable monomer composition 10 wherein the suspension stabilizer is a polymerizable monomer composition 10.
The method for producing colored resin particles according to claim 1, wherein 0.1 to 30 parts by weight is used with respect to 0 parts by weight.