JP2005068381A - Solvent discoloration resistant dye-colored spherical particle of polymer and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide dye-colored spherical particles of a polymer, colored by an oil soluble dyestuff, having an excellent dissolution resistance against a solvent and excellent discoloration resistance associated with the elution of the colored dyestuff, and a method for producing the same. <P>SOLUTION: The dye-colored spherical particles of the polymer having a shell-core structure containing the dye stuff is provided by cross-linking a shell layer of a (meth)acrylic polymer formed by performing a seed polymerization of a hydrophobic (meth)acrylic monomer containing the oil soluble dye stuff and core particles in an aqueous emulsion system, by a cross-linking agent of which molecular structure is expressed by formula (1), having more hydrophilic tendency than that of the (meth)acrylic monomer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to spherical particles of a dye-colored organic polymer excellent in solvent-bleaching resistance of a colored dye. More specifically, the spherical particles of a dye-colored organic polymer colored with an oil-soluble dye are superior to a solvent. The present invention relates to solvent-bleachable dye-colored polymer spherical particles which are solvent-resistant and have excellent resistance to fading associated with solvent elution of colored dyes, and a method for producing the same.

  In the past, nano-sized toner for electrophotographic image formation, ink for IJ (inkjet) printer, ink for printing, ink for writing, ink for stamping, coating agent, paint, cosmetics, etc. in connection with colored fine particles Micron-sized colored polymer spherical fine particles are widely used as various coloring materials. Typically, such colorants are used as fluids, viscous bodies, pastes or solid bodies of any solid-liquid dispersion emulsion containing an aqueous or oily solvent. Further, for the aqueous or oil-based dispersion solvent, it is generally important that the coloring is fading resistant to the dispersion solvent and is resistant to the dispersion solvent including the particulate material. In recent years, as such a solid-liquid dispersion system, as a tracer for a diagnostic agent, and in a display device such as a PLD, colored fine spherical particles as a display medium are dispersed in an insulating organic fluid.・ Migration to display images and prints.

  Conventionally, various dye-colored spherical particles have been proposed in which spherical particles of an organic polymer are prepared by polymerizing a polymerizable monomer in which a dye is dissolved during polymerization of the polymer to encapsulate the dye. The organic polymer spherical particles thus prepared contain the dye during particle formation to prevent the dye from eluting in the reaction polymerization system, and as already mentioned above, the colored dye in actual use as a colorant. Must be prevented from fading due to elution into the dispersion solvent (or dispersion fluid).

  Under such circumstances, for example, [Patent Document 1] describes a monomer composition containing a specific monomer used for writing ink, printing ink, IJ recording ink, paint, color filter, and the like. Containing nano-sized colored fine particles obtained by emulsion polymerization of a product, an oil-soluble dye, and an organosilicon monomer in combination with a polymerization initiator, a reactive emulsifier (or polymerizable emulsifier) and a non-reactive emulsifier Colored resin emulsions have been proposed. In particular, it has been proposed as a colored resin emulsion in which a dye is uniformly mixed at a high concentration and excellent in durability such as heat resistance, light resistance, solvent resistance, water resistance and peel resistance, and its colored fine particles.

  In recent years, electrophoretic display devices have been disclosed in JP-A-9-185087, [Patent Document 2], etc., in connection with chargeable colored resin fine particles that are electrically charged and electrophoresed in an electrophoretic display cell. Has been proposed. For example, [Patent Document 2] proposes an electrophoretic display device that enables display contrast by simple matrix driving, and in a cell in which a transparent organic insulating fluid such as silicone oil, toluene, xylene, and high-purity petroleum is enclosed. Colored resin particles having an average particle diameter of 0.5 to 20 μm relating to black, white or RGB are described as the charged charged electrophoretic fine particles.

  [Patent Document 3] proposes a method for producing acrylic spherical particles by a seed polymerization method, and is a polyfunctional monomer such as ethylene glycol dimethacrylate, trimethylolpropane triacrylate (hereinafter abbreviated as TMPTA). It is described that by using a cross-linking agent as a body, polymer spherical particles having good solvent resistance against solvents such as acetone, toluene, phenol, ethyl acetate, and dichloromethane can be obtained.

  Furthermore, [Patent Document 4] proposes acrylic colored resin fine particles having an average particle size of 0.5 to 100 μm containing an oil-soluble dye. For example, a (meth) acrylic monomer and a styrene monomer are used. Colored resin fine particles made of a copolymer are also disclosed. As a preparation method thereof, an acrylic monomer and an oil-soluble dye are absorbed and polymerized on seed particles having an average particle diameter of 0.05 to 1 μm prepared by emulsion polymerization or suspension polymerization dispersed in an aqueous medium. Is. Examples of the seed particles include (co) polymers of (meth) acrylic monomers, styrene (co) polymers, and copolymers of (meth) acrylic monomers and styrene monomers. Examples of acrylic monomers include alkyl (meth) acrylates whose alkyl groups are methyl, ethyl, propyl, butyl, isobutyl, 2-ethylhexyl, cyclohexyl, 2-hydroxyethyl, methoxyethyl, glycidyl, etc., and their polymerization growth It is described that a polyfunctional monomer such as ethylene glycol di (meth) acrylate or trimethylolpropane tri (meth) acrylate (or abbreviated as TMPTA) is cross-linked to an alkyl (meth) acrylate polymer. ing.

JP 2000-297126 A JP2001-249366 JP 08-120005 JP 2001-89510 A

  Under the circumstances as described above, until recently, electrically charged colored organic resin fine particles colored with a dye / pigment are electrically charged in an insulating colorless transparent or colored transparent organic fluid filled in an electrophoretic display cell. A paper-like display (PLD) that automatically migrates and displays images and / or prints has been reviewed as a third display form for practical use. The technical aim of this PLD is to display and erase a high-visibility image many times as long as video display and rewrite frequency are not desired, and it has the characteristics of hard copy and can be rewritten. Furthermore, compared to conventional display devices such as CRTs and liquid crystal devices, and electrophotographic image forming apparatuses such as copiers and laser printers, etc. It is expected as a display form that is excellent in portability and display quality.

  However, since the spherical particles of the colored organic resin, which is the display medium (or display medium), are in a solid-liquid dispersion that is always immersed in an organic fluid (or organic solvent), the display medium (or display medium) The spherical particles of the colored organic polymer of the medium) always have a solvent resistance to the resin itself, and the emphasis is on the resistance to dissolution of the colored dye and the resistance to fading caused by the dissolution. In addition, in order to make the dye coloring of the colored organic polymer spherical particles, which are display media for PLD, fade-resistant in this way, the electric field in the opposing electrode display cell that enables a display form in a solid-liquid dispersion system is possible. It must not impair the chargeability of the system that is easily responsive to electricity. In addition, from the viewpoint of smooth migration display properties, the agglomeration of the migrating particles is prevented, and the spherical particles with a regular particle shape are impaired, such as the monodisperse particles having a small particle size distribution degree (variation degree). must not.

  In addition, as a spherical particle of a colored organic polymer used in connection with a similar solid-liquid dispersion system, conventionally, toner for electrophotographic image formation, ink for IJ printer, ink for printing, ink for writing, coating agent, paint, For cosmetics and the like, nano- to micron-sized colored resin fine particles colored with dyes and pigments, and emulsion fluids, viscous bodies, pastes or solid bodies in which the colored resin fine particles are dispersed are widely used. The colored polymer spherical particles dispersed as such a solid-liquid dispersion are similarly colored organic polymer spherical particles, the resin itself is always solvent resistant, and the colored dye is resistant to dissolution. It is important to be discoloration resistant to the resulting dispersion medium fluid.

  Therefore, for such nano-sized to micron-sized dye-colored organic polymer spherical particles and a method for producing the same, including various proposal examples already described in the above-mentioned patent literature, It has been proposed to react with a monomer and fix it, or to polymerize an aqueous emulsion of a polymerizable monomer that dissolves a dye in the presence of a surfactant and a cosurfactant called a mini-emulsion polymerization method. Yes. Thus, as is clear from the conventional proposal example, the method for preparing the colored resin fine spherical particles for stably fixing the colored dye, which is the coloring material, in the fine resin particles is relatively complicated and not necessarily cost effective. In fact, it is not an inexpensive manufacturing method, and the colored fine particles obtained are related to the solvent resistance, and the colored dyes are not necessarily fully satisfied with respect to the solvent fading resistance.

  From the above, the object of the present invention is to color filters, inks for IJ printers, inks for printing, inks for writing, stamp inks, etc., color materials such as coating agents, paints, cosmetics, or PLDs. As is clear from any application of the display medium used, the coloring of the dye dispersed in various organic fluids (or organic solvents) as an emulsion fluid, emulsion viscous or emulsion solid in a solid-liquid dispersion system It is an object to provide dye-colored polymer spherical particles of a (meth) acrylic polymer, wherein the organic polymer spherical particles are excellent in solvent resistance and solvent fading resistance.

  Another object of the present invention is to provide nano- to micron-sized dye-colored spherical particles that are excellent in dissolution resistance and solvent fading resistance as described above, without requiring a special process. An object of the present invention is to provide a method for producing a dye-colored polymer spherical particle having excellent solvent fading resistance, characterized by being efficiently prepared.

  As a result of intensive studies on the above-mentioned problems, the inventors of the present invention tend to be more hydrophilic than (meth) acrylic polymerizable monomers in aqueous emulsion systems containing (meth) acrylic polymerizable monomers and oil-soluble dyes. When the cross-linking agent type is selected and the dye-colored spherical particles having a shell-core structure are cross-linked and polymerized, the obtained dye-colored polymer particles are resistant to organic solvents such as alcohol, acetone, MEK, and toluene. The present invention has been completed by finding that it is soluble and the colored dye is remarkably excellent in solvent fading resistance.

  According to the present invention, the core particle colored with an oil-soluble dye is formed so as to cover the shell particle, which is a crosslinked polymer of a (meth) acrylic monomer, by a seed polymerization reaction method. It is a dye-colored spheroid having a shell-core structure. This oil-soluble dye is encapsulated in the core particles during the reaction polymerization in which the shell layer is formed, and a cross-linking agent that is a polyfunctional monomer having a specific molecular structure is formed near the surface of the shell layer. A dye-colored polymer spherical particle having a shell-core structure, which is cross-linked so as to be more closely localized [shell layer of crosslinked polymer of acrylic monomer-color core particle of dye inclusion] .

  That is, the acrylic polymer dye-colored spherical particles colored with an oil-soluble dye and having excellent solvent fading resistance are formed by coating a core layer with a shell layer as a cross-linked polymer. It has a structure.

  Further, the shell layer formed so as to cover the core particles is polymerized and formed by an aqueous emulsion system (or aqueous emulsion system) containing a (meth) acrylic monomer, an oil-soluble dye, and core particles (meth). It is a cross-linked polymer of acrylic monomers, and the cross-linking structure is that the cross-linking agent having a specific molecular structure to be used is cross-linked so that it is more closely localized in the surface vicinity layer of the shell layer. Dye-colored polymer spherical particles (hereinafter sometimes simply referred to as colored spherical particles).

This cross-linking agent is trimethylolpropane having a specific molecular structure that tends to be more hydrophilic than the (meth) acrylic monomer used for shell layer formation from the molecular structure represented by the following formula (1). It is a tri (meth) acrylate (or abbreviated as TMPTA) type polyfunctional monomer. Moreover, in the present invention, this TMPTA is (EO) -TMPTA or (PO) -TMPTA modified with ethylene oxide (hereinafter abbreviated as EO) or propylene oxide (hereinafter abbreviated as PO). Modified trimethylolpropane tri (meth) acrylate is used as a crosslinking agent.

  From the above, since it is a dye-colored polymer spherical particle having a shell-core structure having such structural characteristics, the dye contained in the core particle is remarkably excellent in solvent fading resistance. Dye-colored polymer spherical particles characterized by the following.

  Further, according to the present invention, the colored spherical particles having excellent solvent resistance and solvent fading resistance desired by the shell layer having such a characteristic cross-linked structure are converted into oil-soluble dyes by a polymerization reaction coloring method in an aqueous emulsion system. As a colored spherical particle having a shell-core structure and excellent in solvent fading resistance, the core particle is encapsulated and the core particle is coated with a shell layer which is a (meth) acrylic crosslinked polymer. Provided is a method for producing a dye-colored polymer spherical particle having excellent solvent fading resistance, characterized in that it can be easily and highly efficiently prepared without requiring a process.

  That is, according to the method for producing dye-colored spherical particles of a (meth) acrylic polymer having a shell-core structure according to the present invention, a core in which an oil-soluble dye is encapsulated and colored by a polymerization reaction coloring method in an aqueous emulsion system. In the vicinity of the surface of the shell layer formed so that the crosslinked polymer of the (meth) acrylic monomer is coated on the particle, it has a shell-core structure that is crosslinked so that the crosslinking agent is more densely localized. Dye-colored spherical particles of (meth) acrylic polymer are produced.

で表される架橋剤を溶解させた原料溶液を調製させる。 First, the (meth) acrylic monomer has an oil-soluble dye and a molecular structure that is more hydrophilic than the (meth) acrylic monomer.

A raw material solution in which the cross-linking agent represented by is dissolved is prepared.

  Next, after adding a predetermined amount of water, a predetermined amount of emulsifier, and a predetermined amount of polymerization initiator, the spherical core particles of the organic polymer prepared in advance are dispersed at a concentration of 5 to 40% expressed in solid content concentration. Aqueous emulsification in which emulsion-like spherical particles are formed by coating a (meth) acrylic monomer that dissolves oil-soluble dye around spherical core particles by adding a predetermined amount of aqueous emulsion suspension under stirring. A reactive suspension of the system is prepared.

Then, under stirring, the reactive aqueous suspension is heated and colored in multiple stages in the temperature range of 40 to 95 ° C., the dye is encapsulated and colored, the shell layer is polymerized, the shell layer is crosslinked and aged. Thus, dye-colored spherical particles of a (meth) acrylic polymer having a shell-core structure are produced as dye-colored polymer spherical particles having excellent solvent fading resistance.

From the above, the dye-colored acrylic polymer spherical particles having excellent solvent fading resistance according to the present invention have a molecular structure represented by the following formula (1) in order to crosslink the shell layer when the shell layer is formed on the core particle. A modified polyfunctional monomer (referred to as EO-TMPTA or PO-TMPTA) to which ethylene oxide (referred to as EO) and / or propylene oxide (referred to as PO) of trimethylolpropane triacrylate (referred to as TMPTA) is added, Moreover, the modified EO (or modified PO) -TMPTA added with EO or PO in the range of 6 to 60 mol is cross-linked to the shell layer of the (meth) acrylic polymer that is formed so as to cover the core particles. Yes.

  Therefore, in the aqueous emulsion system of the present invention, a (meth) acrylic monomer layer interposed so as to spherically coat the surface of the spherical core particles encapsulated with the oil-soluble dye to be dispersed is formed by polymerization (meta ) When the modified EO (or modified PO) -TMPTA having this specific molecular structure reacts as a cross-linking agent with respect to the shell layer of the acrylic polymer layer, in the present invention, in the aqueous emulsion system, Because it acts as a hydrophilic cross-linking agent, the cross-linking direction of the cross-linking agent advances from the core particle direction toward the (meth) acrylic polymer layer that is the hydrophilic side of the dispersed emulsion particles. Then, this modified EO (or modified PO) -TMPTA cross-linking agent cross-links so as to be more densely localized in the vicinity of the surface layer of the shell layer to be formed. It is believed to form a E le layer.

  As a result, as is apparent from the fact relating to the solvent fading resistance shown in the examples described later, the surface layer near the surface of the shell layer is formed with a denser cross-linked structure than the core particle layer side. The elution of the colored dye contained in the organic solvent to be immersed next is effectively guarded by this shell layer, and the diffusion and penetration of the solvent is remarkably suppressed, and the elution of the colored dye is remarkably suppressed. This makes it difficult to effectively prevent discoloration of the colored dye by the solvent.

  Hereinafter, the best mode for carrying out the invention in connection with the (meth) acrylic dye-colored polymer spherical particles having excellent solvent fading resistance according to the present invention and the production method thereof will be further described.

シェル層に形成する架橋構造は、この反応系での特性が生かされて、その表面近傍層により密に局在するように架橋されてなる［アクリル系ポリマーの架橋重合体なるシェル層−染料内包着色のコア粒子］のシェル−コア構造の染料着色ポリマー球状粒子であることを特徴としている。 As already described above, the dye-colored colored spherical particles of the (meth) acrylic polymer having a shell-core structure in which the oil-soluble dye according to the present invention is encapsulated and colored are formed on the core particle by the seed polymerization reaction method. It is characterized by being dye-colored polymer spherical particles having a shell-core structure formed so as to cover a shell layer as a crosslinked polymer of the polymer. Moreover, this oil-soluble dye is encapsulated in the core particles at the time of the reaction polymerization for forming the shell layer, and by the polyfunctional monomer having a specific molecular structure represented by the following formula (1),

The cross-linked structure formed in the shell layer is cross-linked so as to be localized more closely in the layer near the surface by taking advantage of the characteristics in this reaction system [shell layer of acrylic polymer cross-linked polymer-dye inclusion Colored core particles] are dye-colored polymer spherical particles having a shell-core structure.

  In the present invention, the molecular structure of the crosslinking agent having such a specific structure is represented in order to make use of the characteristics of the aqueous emulsion reaction system in which the shell layer is formed and to localize and crosslink near the surface of the shell layer. In the above formula (1), the [l + m + n] numerical value is preferably 6 to 60, more preferably 6 to 50, and particularly preferably 6 to 18, which is suitably used as a crosslinking agent as appropriate in the present invention. Can do. When this value is 6 or less, which is the lower limit, in this solid-liquid dispersion aqueous emulsion, the cross-linking agent tends to be more hydrophobic than the (meth) acrylic monomer in terms of dispersion characteristics already defined above. It is difficult to form a crosslinked structure that exhibits the above-described superiority in connection with the crosslinking reaction. On the other hand, when the upper limit of 60 is exceeded, the hydrophilicity is rather too strong, and it is not preferable because it behaves as a reactive emulsifier rather than a crosslinking monomer and significantly inhibits the polymerization stability of the shell layer. Therefore, in the present invention, the polyfunctional monomer before modification is not necessarily limited to a modified polyfunctional monomer corresponding to trimethylolpropane tri (meth) acrylate (TMPTA), but other than TMPTA, for example, pentaerythritol tri (meth) acrylate, Pentaerythritol tetra (meth) acrylate, glycerin tri (meth) acrylate, 1,1,1-trishydroxymethylethanetri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolpropane tetra (meth) acrylate And polyfunctional monomers obtained by similarly modifying dipentaerythritol hexa (meth) acrylate and the like.

  Further, the dye-colored spherical particles of the (meth) acrylic polymer having a shell-core structure according to the present invention are coated with (meth) the core particles using the spherical core particles prepared in advance as described above. This is a colored spherical particle having a shell-core structure formed by coating a crosslinked polymer of an acrylic polymer. In the present invention, the polymer species of the core particle is not particularly limited, and may be (meth) acrylic or non- (meth) acrylic, such as (meth) acrylic. Examples of the system include (meth) acrylic, (meth) acrylic-styrene, fluorine-substituted (meth) acrylic, and fluorine-substituted (meth) acrylic-styrene.

  In addition, the core particles used in this way preferably have an average particle size expressed on a volume basis of 0.05 to 40 μm, and more preferably 0.07 to 20 μm. The dispersion can be dispersed in an aqueous emulsion to form a shell layer. The dye-colored spherical particles of the (meth) acrylic polymer having a shell-core structure according to the present invention obtained by forming a shell layer on the core particles having such a particle size preferably have an average particle size of 0.00 on the volume basis. Dye-colored polymer spherical particles having a particle size of 1 to 50 μm, more preferably 0.15 to 30 μm, and excellent in solvent fading resistance, can be suitably provided.

  In addition, the solvent-bleachable dye-colored spherical particles according to the present invention are used as, for example, a desired electrostatic electrostatic toner used in an electric field system of an electrophotographic image apparatus, or used in a PLD as desired chargeability. As a display medium that exhibits electrophoretic properties, the average particle diameter charged uniformly by the particle surface is in the range of 1.0 to 30 μm, preferably in the range of 1.0 to 10 μm, and more preferably in the range of 1.0 to Since it can be used for the PLD of 5 μm or as the charged colored particles constituting the electrostatic toner, when the above-mentioned shell layer is formed, a (meth) acrylic monomer species rich in surface chargeability is previously selected. A shell layer can be formed by appropriately selecting.

  Therefore, the (meth) acrylic monomer used in the present invention is a polymerizable monomer for forming a shell layer in the present invention, and dissolves an oil-soluble dye or a crosslinking agent having a specific molecular structure as described above. In addition, in the present invention, preferably a (meth) acrylic monomer described below, in which polymer spherical core particles prepared in advance are dispersed to form emulsion particles of an aqueous emulsion system. A monomer can be used suitably suitably.

  Examples of (meth) acrylic monomers for forming a shell layer in the present invention include, for example, alkyl acrylate esters; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) acrylic Isopropyl acid, butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, (meth) Lauryl acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, phenyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, (meth ) Propoxyethyl acrylate, butoxye (meth) acrylate , Ethoxypropyl (meth) acrylate and the like, examples of the dialkylaminoalkyl (meth) acrylate; diethylaminoethyl (meth) acrylate and the like, and examples of the (meth) acrylic acid alkoxyesters; ) Methoxyethyl acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxypropyl (meth) acrylate, and the like of (poly) alkylene glycol Diacrylates: ethylene glycol diacrylate, diethyl glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol And (poly) alkylene glycol dimethacrylates include: ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene Examples include glycol dimethacrylate, polyethylene glycol diacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate, and more. Examples of the acid esters include trimethylolpropane trimethacrylate. Examples of the polyvalent methacrylic acid ester include trimethylolpropane trimethacrylic acid ester. Examples of vinyl compounds include vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl persate, vinyl laurate, vinyl stearate, vinyl benzoate, p- Examples thereof include vinyl t-butylbenzoate. Further, acrylic acid esters of alicyclic alcohols such as cyclohexyl acrylate, methacrylic acid esters of alicyclic alcohols such as cyclohexyl methacrylate, and the like can be given.

  In addition, the dye-colored polymer spherical particles according to the present invention are used in various applications, for example, as a display medium for PLD. Modified EO (or modified PO) -TMPTA which is a (meth) acrylic monomer having a group and / or a substituent in the molecule and used as a crosslinking agent for the reason already described in the present invention as the functional group or substituent In the range which does not inhibit the hydrophilic tendency, for example, carbonyl group, vinyl group, phenyl group, amino group, amide group, imide group, hydroxyl group, halogen group, sulfonic acid group, epoxy group, urethane bond and the like can be mentioned. it can. Depending on the type of the functional group or substituent, the chargeability may include monomer species that tend to exhibit (−) chargeability and (+) chargeability, respectively.

  Therefore, examples of the polymerizable monomer for forming a shell layer that tends to have (−) chargeability include (meth) acrylic acid annealed esters; phenyl (meth) acrylate, benzyl (meth) acrylate, and the like. Examples of the halogen group include: vinyl salicylate, vinylidene chloride, vinyl chlorohexanecarboxylate, 2-chloroethyl acrylate, 2-chloroethyl methacrylate, and the nitrile type; acrylonitrile, methacrylonitrile, and the like. Examples of epoxy group-containing polymerizable compounds include: glycidyl methacrylate, maleic acid mono- and diglycidyl esters, fumaric acid mono- and diglycidyl esters, crotonic acid mono- and diglycidyl esters, tetrahydrophthalic acid mono- and di- Glycidyl ester, Ita Mono- and diglycidyl esters of acid, mono- and diglycidyl esters of butenetricarboxylic acid, mono- and diglycidyl esters of citraconic acid, mono- and glycidyl esters of allyl succinic acid, p-styrene carboxylic acid Examples of the epoxy group-containing polymerizable compounds include: allyl glycidyl ether, glycidyl ether acrylate, glycidyl ether methacrylate, acrylate-2-ethylglycidyl ether, methacrylic acid Examples include 2-ethylglycidyl ether, 2-methylallyl glycidyl ether, styrene-p-glycidyl ether, glycidyl acrylate, and the like. Examples of the hydroxy group-containing polymerizable compounds include: acrylic acid-2- Droxyethyl, methacrylic acid-2-hydroxyethyl, acrylic acid-2-hydroxypropyl, monoester of acrylic acid or methacrylic acid and polypropylene glycol or polyethylene glycol, lactones and 2-hydroxyethyl (meth) acrylate Examples of fluorine vinyl monomers include: fluorine-substituted methacrylic acid alkyl ester, fluorine-substituted acrylic acid alkyl ester, etc., and unsaturated carboxylic acids: acrylic acid, methacrylic acid, tetrahydro Phthalic acid, itaconic acid, citraconic acid, crotonic acid, maleic acid, fumaric acid, isocrotonic acid, norbornene dicarboxylic acid, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid, etc. In addition, anhydrous as these derivatives Maleic acid, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic anhydride, acid halide, etc. Examples of vinyl compound monomers include: vinyltrimethyoxysilane, γ-methacryloxypropyltrimethoxysilane, trimethosilylpropylanilamine, 2-methoxyethoxytrimethoxysilane, and the like.

  In addition, (poly) alkylene glycol diacrylates include: ethylene glycol diacrylate, diethyl glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate Examples of the dimethacrylic acid ester of (poly) alkylene glycol include: ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and triethylene glycol dimethacrylate. Methacrylic acid ester, polyethylene glycol diacrylic acid ester, propylene glycol dimethacrylic acid ester, dipropylene glycol Dimethacrylic acid ester of tripropylene, dimethacrylic acid ester of tripropylene glycol, and the like as fluorine-substituted (meth) acrylic monomers; trifluoromethylmethyl (meth) acrylate, (meth) acrylic acid 2-trifluoromethylethyl, (meth) acrylic acid-2-perfluoromethylethyl, (meth) acrylic acid-2-perfluoroethyl-2-perfluorobutylethyl, (meth) acrylic acid-2- Examples thereof include perfluoroethyl, perfluoromethyl (meth) acrylate, diperfluoromethylmethyl (meth) acrylate, and the like.

  On the other hand, as an (+) chargeable acrylic monomer, for example, amide group-containing vinyl monomers: methacrylamide, N-methylol methacrylamide, N-methoxyethyl methacrylamide, N-butoxymethyl methacryl Examples of the amino group-containing ethylenically unsaturated compounds include: aminoethyl (meth) acrylate, propylaminoethyl (meth) acrylate, dimethylaminoethyl methacrylate, aminopropyl (meth) acrylate, methacryl Alkyl ester derivatives of acrylic acid or methacrylic acid such as phenylaminoethyl acid, cyclohexylaminoethyl methacrylate, vinylamine derivatives such as N-vinyldiethylamine and N-acetylvinylamine, allylamine, methacrylamine, N Allylamine derivatives such as methylacrylamine, N, N-dimethylacrylamide, N, N-dimethylaminopropylacrylamide, acrylamide derivatives such as acrylamide and N-methylacrylamide, aminostyrenes such as p-aminostyrene, N-methylol Examples include (meth) acrylamides such as (meth) acrylamide and diacetone acrylamide, 6-aminohexyl succinimide, 2-aminoethyl succinimide, and the like.

  Further, for example, acrylic acid such as aminoethyl (meth) acrylate, propylaminoethyl (meth) acrylate, dimethylaminoethyl methacrylate, aminopropyl (meth) acrylate, phenylaminoethyl methacrylate, cyclohexylaminoethyl methacrylate, etc. Or alkyl ester derivatives of methacrylic acid, vinylamine derivatives such as N-vinyldiethylamine, N-acetylvinylamine, allylamine, methacrylamine, N-methylacrylamine, N, N-dimethylacrylamide, N, N-dimethyl Allylamine derivatives such as aminopropylacrylamide, acrylamide derivatives such as acrylamide and N-methylacrylamide, aminostyrenes such as N-aminostyrene, and 6-aminohexyl succinic acid , Monomers having an amino group-containing ethylenic unsaturated bond such as 2-aminoethyl succinimide can be suitably used as appropriate.

  Therefore, the dye as the colorant used in the present invention is an achromatic black oil-soluble dye and / or a chromatic color oil-soluble dye from various uses. As long as it can be dissolved or uniformly dispersed, it is appropriately selected without particular limitation. In the present invention, any oil-soluble dye that is preferably less soluble in water than the monomer is suitably used. Examples of the oil-soluble dye include black Solvent Black 27Cr (trivalent) 5%, Pigment Black 7 / water, red Solvent RED8Cr (trivalent) 5.8%, blue Solvent Blue 35, yellow Solvent Yellow 16, Solvent Yellow 33, magenta Solvent RED149, Solvent RED49, Solvent RED52, cyan 4% Solvent Blue 70Cu, orange Solvent Orange 80, Solvent Orange 6Cr 2.7%, brown Solvent Yellow 116, and the like. In addition, for example, dyes commonly used in writing recording liquids such as clarine, perylene, dicyanopinyl, azo, quinophthalone, aminopyrazole, methine, dicyanoimidazole, indoaniline, phthalocyanine, A leuco dye used as a heat-sensitive recording paper or a temperature-sensitive color material, and, for example, rhodamine B stearate (red 215), tetrachlorotetrabromofluoresene (red 218), tetrabromofluorescene (red 223) No.), Sudan 3 (red No. 225), dibromofluorescein (orange No. 201), diiodofluorescein (orange No. 206), fluorescein (yellow No. 201), quinoline yellow SS (yellow No. 204), quinizarin green SS ( Green 202), azurin purple SS (purple 201), medicine Cosmetics such as Scarlet (Red 501), Oil Red XO (Red 505), Orange SS (Orange 403), Yellow AB (Yellow 404), Yellow OB (Yellow 405), Sudan Blue B (Blue 403) The tar-type dye currently used for can also be mentioned. In the present invention, these dyes are used alone or in admixture of two or more, and various direct dyes, acid dyes, basic dyes, azoic dyes, reactive dyes, fluorescent dyes and fluorescent dyes are used as necessary. A whitening agent or the like can be appropriately selected and used according to a desired color tone.

  Therefore, in the present invention, these dyes are used alone or in admixture of two or more kinds, and various direct dyes, acid dyes, basic dyes, azoic dyes, reactive dyes, fluorescent dyes as necessary. In addition, it is possible to disperse in a fluorescent whitening agent or even a (meth) acrylic monomer, for example, titanium white, bengara, ultramarine blue, carbon black (or chargeable carbon black), magnetic fine powder, conductive metal fine powder. Various inorganic / organic dyes and pigments such as bodies and functional powders can also be used. In addition, these dyes and pigments (or dyes and pigments) are used in accordance with the desired color tone, etc., in the above-described various monomer types for forming colored spherical fine particles having a shell-core structure, and the use of the colored particles. It can be selected and used as appropriate.

  Therefore, as a method for producing a dye-colored polymer spherical particle having excellent solvent resistance and solvent fading resistance according to the present invention as described above, the (meth) acrylic monomer described above and the crosslinking agent having the specific molecular structure described above are used. , And the oil-soluble dyes described above, for example, can be prepared under emulsion polymerization, suspension polymerization or seed polymerization, and a typical production method thereof will be described below.

  In the production method in the present invention, the core particles prepared in advance have an average particle size expressed by volume in the range of 0.05 to 40 μm, preferably in the range of 0.1 to 20 μm, and preferably, An aqueous suspension of core particles having a substantially spherical shape, more preferably substantially monodispersed particles, and dispersed at a concentration of 5 to 40% expressed as a solid content concentration, is appropriately prepared.

  As already described above, the core particles used in the present invention may be acrylic or non-acrylic, and are used without particular limitation. For example, as an acrylic core particle, a system containing 200 to 350 parts by weight of water in 100 parts by weight of a (meth) acrylic monomer is heated to 65 to 85 ° C. with strong stirring, and then persulfuric acid. Acrylic spherical polymer core particles having an average particle size of 0.05 to 0.5 μm are prepared by adding 0.3 to 0.6 parts by weight of potassium and polymerizing under heating and stirring. . Usually, the core particle prepared in this way can be used as an aqueous suspension (S-1) of the core particle which is expressed by solid content concentration and is dispersed at 5 to 30% by weight. Next, separately, 0.8 to 1.2 parts by weight of benzoyl peroxide is dissolved in 80 to 95 parts by weight of the (meth) acrylic monomer under strong stirring, and then 180 to 250 of water with strong stirring. For example, 3.0 to 4.0 parts by weight of polyoxyethylene polycyclic phenyl ether sulfate ester salt and 0.05 to 0.15 parts by weight of sodium nitrite are mixed as an emulsifier. Next, after adding 28 to 35 parts by weight of the aqueous suspension (S-1), the reaction is performed in the range of 60 to 80 ° C. with gentle stirring, and a new (meth) acrylic monomer is superposed and formed. An aqueous suspension (S-2) of core particles in which core particles having an average particle diameter of 0.1 to 2 μm are dispersed at 5 to 40% by weight in terms of solid content concentration is prepared. Thus, by repeating the repeated polymerization formation in the same manner, the core particles having an average particle diameter of 0.05 to 40 μm are expressed in terms of solid content concentration and dispersed at a concentration of 5 to 40%. Aqueous suspension (SN) can be prepared as appropriate.

で表される架橋剤を、好ましくは、５〜５０重量部で、更に好ましくは、８〜４０重量部を溶解して原料溶液を調製する。このような水性乳化系において、本発明においては、この架橋剤が下限値の５重量部以下では、本発明が目的とする架橋効果が発揮できず、一方、上限値の５０重量部を超えると、架橋剤が水に溶解傾向になり、重合安定性を低下させて、このように親水性傾向にある架橋剤を使用することによる本発明が目的とするシェル層の架橋構造を形成させることが不可能である。 In the present invention, as already described above, the core particle thus prepared is encapsulated with an oil-soluble dye, while forming a shell layer of (meth) acrylic polymer and crosslinking the shell layer. A shell-core structure in which the cross-linking agent is cross-linked and polymerized so that the cross-linking agent is more densely localized in the vicinity of the surface of the shell layer by utilizing the dispersion characteristics of the cross-linking agent in the aqueous emulsion reaction system, and the dye is encapsulated and colored (Meth) acrylic polymer having colored spherical particles. First, per 100 parts by weight of the (meth) acrylic monomer, 1 to 50 parts by weight of the oil-soluble dye, and as apparent from the molecular structure, it tends to be more hydrophilic than the (meth) acrylic monomer for forming the shell layer. The molecular structure is the following formula (1):

Is preferably 5 to 50 parts by weight, and more preferably 8 to 40 parts by weight, to prepare a raw material solution. In such an aqueous emulsification system, in the present invention, when the cross-linking agent is 5 parts by weight or less of the lower limit value, the cross-linking effect intended by the present invention cannot be exhibited, while when the upper limit value of 50 parts by weight is exceeded. The cross-linking agent tends to dissolve in water, lowers the polymerization stability, and thus forms a cross-linked structure of the shell layer intended by the present invention by using a cross-linking agent that tends to be hydrophilic. Impossible.

  Next, similarly, per 100 parts by weight of the (meth) acrylic monomer, 50 to 500 parts by weight of water, and as an emulsifier, for example, 7 to 12 parts by weight of polyoxyethylene polycyclic phenyl ether sulfate, and polymerization start As an agent, for example, 0.05 to 0.15 parts by weight of sodium nitrite was added and stirred vigorously, and then prepared in advance, for example, the average particle diameter represented by the above-mentioned volume standard was 0.05 to 40 μm. 1 to 50 parts by weight of an aqueous suspension (SN) in which spherical core particles of an organic polymer are dispersed at a concentration of 5 to 40% expressed as a solid content concentration is added with vigorous stirring. As a result, the aqueous suspension is a reactive suspension of an aqueous emulsion system in which emulsion particles of core particles formed so as to coat (meth) acrylic monomers in which oil-soluble dyes are dissolved around spherical core particles are dispersed. Prepared.

  Then, under stirring, this reactive aqueous suspension is colored by encapsulating the dye while raising the temperature in a multi-stage within a temperature range of 40 to 95 ° C., polymerizing the shell layer, crosslinking the shell layer, and aging. Thus, an acrylic polymer dye-colored spherical particle having a shell-core structure, for example, having an average particle size expressed by volume of 0.1 to 50 μm is formed. In the present invention, a colored dye can be produced as a dye-colored polymer spherical particle having excellent solvent fading resistance.

  From the above, a shell characteristic of a cross-linked structure is obtained by encapsulating an oil-soluble dye in core particles by a polymerization reaction coloring method in an aqueous emulsion system and coating the core particles with a shell layer that is a (meth) acrylic cross-linked polymer. It is possible to easily and efficiently prepare dye-colored spherical particles of a (meth) acrylic polymer excellent in dissolution resistance and solvent fading resistance desired by forming in a layer without requiring a special process. It is possible to provide a method for producing a dye-colored polymer spherical particle having excellent solvent fading resistance.

  As the polymerization initiator, for example, in preparing the core particles, persulfates such as potassium persulfate and ammonium persulfate, peroxides such as benzoyl peroxide and laurium peroxide, asobisisobutyronitrile, etc. An azo compound etc. are mentioned. Examples of polymerization initiators preferably used for coloring and polymerization include azo polymerization initiators such as 2,2′-azobis (2-methylpropopionitrile) and 2,2′-azobis (2-methylbutylene). Tyrolonitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-dichloropropylpropionitrile), 1,1′-azobis (cyclohexane-1-carbonitrile) , Dimethyl-2,2′-azobis (2-methylpropionate) and the like. Therefore, in the present invention, at the time of coloring and polymerization, these polymerization initiators are preferably 0.01 to 5 per 100 parts by weight of the (meth) acrylic monomer when preparing the core particles. May be in the range of 0.5 to 2 parts by weight.

  Moreover, as an emulsifier, it can select from the anionic surfactant normally used, a cationic surfactant, or a nonionic surfactant as needed, and can use it individually or in combination. Examples of anionic surfactants include sodium and potassium salts such as dodecyl benzene sulfonate, dodecyl benzene sulfonate, and tridecyl benzene sulfonate. Cationic surfactants include cetyltrimethylammonium promide, hexadecyl chloride, and the like. Examples thereof include pyridinium and hexadecyltrimethylammonium chloride, and examples of the nonionic surfactant include lipiridinium. In addition, anionic, cationic or nonionic reactive emulsifiers (for example, emulsifiers having a polymerizable group such as acryloyl group and methacryloyl group) may be used without particular limitation. In the present invention, emulsifiers preferably used for dye coloring and shell layer formation include alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, polyethylene glycol alkyl ethers such as polyethylene glycol nonylphenyl ether, and polyoxyethylene alkyl ethers. , Polyoxyethylene polycyclic phenyl ether, allyl ether and sulfate thereof. Therefore, these emulsifiers may usually be in the range of 0.01 to 5 parts by weight per 100 parts by weight of the (meth) acrylic monomer. In the present invention, these emulsifiers are known per se. Other additives (compounding agents) such as heat stabilizers, dispersants, preservatives, surface tension regulators, pH regulators, antifoaming agents, rust inhibitors, chelating agents, antioxidants, antistatic agents An agent, a near-infrared absorber, an ultraviolet absorber, a fluorescent agent, a fluorescent brightening agent, a fragrance and the like can be added and dispersed according to a formulation known per se.

  From the above, the (meth) acrylic dye-colored polymer spherical particles having a particle size of nano to micron according to the present invention are used in various applications as a colorant (or color material) having excellent solvent fading resistance. Involved in solid-liquid dispersion colored emulsion fluids, viscous bodies, pastes, solids, already known colors for IJ printers, printing inks, writing inks, stamping inks, etc., thermal recording paper It can be suitably used suitably for color developing agents, temperature-sensitive color materials, coating agents, paints and cosmetics, color filters and the like. Further, it can also be suitably used for colored spherical particles of display media such as DPL, which are used as a similar solid-liquid dispersion.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

<Evaluation of color tone>
In this example, in order to evaluate the color tone of the dye-colored particles, an aqueous dispersion of colored particles (10 parts by weight as a solid content) was used as a test sample, 3 g of the sample was placed in a container, and a thickness of 1.7 mm was formed on the top. Cover with a transparent glass plate, and measure with a color ace MODEL TC-P3 manufactured by Tokyo Denshoku Co., Ltd., and L ^* a ^* b ^* solid color system value (L ^* , A ^* , b ^* ) are obtained respectively. The L ^* value obtained here represents lightness (L ^* is zero when black and L ^* is 100 when white), and chromaticity indicating hue and saturation is represented by a ^* and b ^* values, respectively. The + a ^* value is an indicator in the red direction, the -a ^* value is in the green direction, the + b ^* value is in the yellow direction, and the -b ^* value is in the blue direction. As a reference example, for example, color values L ^* a ^* b ^* values of yellow (Y), magenta (M), and cyan (C) used as Japan colors are as shown in [Table 1].

<Preparation of aqueous suspension of core particles>
100 parts by weight of methyl methacrylate (MMA), a (meth) acrylic monomer, and 300 parts by weight of water were added to a 1 liter four-necked flask equipped with a thermometer and a nitrogen inlet tube and stirred and mixed. Further, the temperature was raised to about 80 ° C. with stirring in a nitrogen atmosphere. Next, 0.5 part by weight of potassium persulfate was added to the mixed solution, reacted for about 6 hours while maintaining at about 80 ° C., and observed with an electron microscope, the average particle size was 0.4 m, and a substantially spherical shape. An aqueous suspension (S-1) was prepared in which the particles were expressed as a solid content concentration and dispersed at 26.5% by weight. Next, 91.7 parts by weight of MMA and 1.3 parts by weight of benzoyl peroxide are charged into a similar one-liter four-necked flask and dissolved, and further 200 parts by weight of water, polyoxyethylene 3.3 parts by weight of polycyclic phenyl ether sulfate and 0.1 parts by weight of sodium nitrite were added and mixed with vigorous stirring, and then 31.3 parts by weight of the aqueous suspension (S-1) described above was added. Added and reacted for 2 hours while gradually raising the temperature from room temperature to 78 ° C., and an aqueous suspension in which substantially spherical particles having an average particle size of 0.9 μm are dispersed at a solid content concentration of 31% by weight (S -2) was prepared. Subsequently, 95 parts by weight of MMA and 1.3 parts by weight of benzoyl peroxide are added and dissolved in the same manner. Further, 200 parts by weight of water and 3.3 parts of polyoxyethylene polycyclic phenyl ether sulfate are added. Part by weight, 0.1 part by weight of sodium nitrite was added and stirred vigorously, 16.1 parts by weight of the above-mentioned aqueous suspension (S-2) was added, and the polymerization reaction was carried out in the same manner. An aqueous suspension (S-3) was prepared in which core spherical particles used in the present invention having a substantially spherical shape of 41 μm were dispersed at a solid content concentration of 32.5% by weight.

(Example 1)
<Preparation of Solvent-Fade Resistant Dye-Colored Polymer Spherical Particles According to the Present Invention>
A black dye-colored acrylic polymer spherical particle having a shell-core structure was prepared using ethylene oxide-modified trimethylolpropane triacrylate [(EO) -TMPTA] as a crosslinking agent for crosslinking the formed shell layer.

  44 parts by weight of MMA, 30 parts by weight of (EO) -TMPTA, and 6 parts by weight of 2-hydroxyethyl methacrylate are charged into a one-liter four-necked flask equipped with a thermometer and a nitrogen inlet tube. did. Next, 1.5 parts by weight of dimethyl-2,2′-azobis-2-methylpropionate, 5 parts by weight of CI solvent black 27, 0.1 part by weight of CI solvent red 8, and CI solvent yellow 16 parts by weight of 0.1 part by weight and dissolved, 250 parts by weight of water, 10 parts by weight of polyoxyethylene polycyclic phenyl ether sulfate as an emulsifier, and 0.1 parts by weight of sodium nitrite And mixed under strong stirring. Next, 61.5 parts by weight of the above-described aqueous suspension (S-3) was added to this aqueous emulsification system, reacted for 2 hours while gradually raising the temperature from room temperature to 78 ° C. After aging for 2 hours, an aqueous suspension was prepared in which approximately monospherical black monodispersed spherical particles having an average particle diameter of 3.9 μm were dispersed at a solid content concentration of 32% by weight. Subsequently, the obtained aqueous suspension was filtered, dried, and powdered black spherical particles were used as Sample A to evaluate the solvent fading resistance of the colored dye.

(Comparative Example 1)
A black colored sphere having a shell-core structure was used in the same manner as in Example 1 except that 30 parts by weight of ethylene glycol dimethacrylate was used as the crosslinking agent in place of the crosslinking agent (EO) -TMPTA used in Example 1. Particles were prepared. The obtained black colored spherical particles had an average particle size of 3.9 μm and were aqueous suspensions dispersed at a solid content concentration of 32% by weight. The black spherical particles obtained in the same manner were used as Sample H-1, and the solvent fading resistance of the colored dye was evaluated.

(Comparative Example 2)
A shell-core structure under exactly the same conditions as in Example 1 except that the 4-liter flask having a volume of 1 liter used in Example 1 was replaced with 69 parts by weight of MMA and 5 parts by weight of (EO) -TMPTA. Of black colored spherical particles were prepared. The obtained black colored spherical particles had an average particle size of 3.9 μm and were aqueous suspensions dispersed at a solid content concentration of 32% by weight. The black spherical particles obtained in the same manner were used as Sample H-2 to evaluate the solvent fading resistance of the colored dye.

<Evaluation of solvent fading resistance>
After washing 100 g of each spherical particle colored with the black dye obtained in Examples and Comparative Examples with methyl ethyl ketone (MEK) until the non-volatile content is 30%, the color saturation (or coloring property) of the black spherical particle is determined. It was measured with a color difference meter (manufactured by Tokyo Denshoku Co., Ltd .: Color Ace Model TC-P3), and the elution resistance of the coloring dye was evaluated from the decrease in the color saturation. The results are shown in [Table 2]. L ^* a ^* b ^* was used as the color system, and the change in L ^* value, which is an evaluation of the blackness, was measured. The closer the L ^* value is to 0, the more black it is, and the closer the L ^* value is to 100, the more white it is.

  As is clear from the results shown in [Table 2], in Sample A according to the present invention, the elution of the dye is suppressed by washing with the solvent MEK twice. On the other hand, in H-1 of the comparative example, there are many dissolved dyes by MEK washing, and the elution is not completely suppressed, and as a result, the color to be perceived is faintly black and discolored to near gray. Furthermore, in the comparative example H-2, the crosslinking degree of the shell layer was insufficient, and sufficient solvent resistance against MEK could not be exhibited. From the above, in the (meth) acrylic polymer dye-colored spherical particles according to the present invention, the surface layer near the surface of the shell layer is more closely cross-linked with (EO) -TMPTA than the core particle layer side, and is secondarily immersed. Effectively suppresses diffusion / penetration of organic solvents such as MEK into particles, elution of colored dyes encapsulated is effectively guarded by this shell layer and remarkably suppresses elution of colored dyes, It effectively prevents discoloration of colored dyes by solvents.

  From the above, the (meth) acrylic dye-colored polymer spherical particles having a shell-core structure according to the present invention are used for various solvents (or various organic fluids) that are secondarily immersed or contacted in various applications. Colored dyes that are solvent-resistant and encapsulated are dye-colored (meth) acrylic polymer spherical particles that are characterized by their outstanding cross-linking shell layer that exhibits outstanding solvent fading resistance. Therefore, it can be provided as colored spherical fine particles excellent in solvent resistance and solvent fading resistance in the following applications.

  Spherical particles colored in chromatic or achromatic black are ballpoint pen ink, IJ printer ink, printing ink, writing ink, stamp ink, other temperature sensitive colorants, coating agents, paints and color makeup. As a color coloring agent such as a colorant, 100 to 500 nm spherical particles dyed and colored in black achromatic colors can be provided as black spherical particles for forming a structural color.

The charged polymer dye colored spherical particles according to the present invention are appropriately prepared as (+) charged or (−) charged particles depending on the functional group of the (meth) acrylic monomer that forms the shell layer. As a desired electrostatic charging toner used in the electric field system of the apparatus, it can be provided as a display medium that exhibits desired charging and electrophoretic properties and displays an image and / or prints for PLD.

Claims (6)

In acrylic dye-colored polymer spherical particles that are colored with oil-soluble dyes and have excellent solvent fading resistance,
The dye-colored polymer spherical particles are colored spherical particles having a shell-core structure in which a core layer is formed with a shell layer as a crosslinked polymer.
The shell layer of the (meth) acrylic polymer formed by polymerization in an aqueous emulsion system containing a (meth) acrylic monomer, an oil-soluble dye, and the core particles has a molecular structure that is more hydrophilic than the (meth) acrylic monomer. The following formula (1)

A solvent-bleachable dye-colored polymer spherical particle, wherein the cross-linking agent represented by the formula (1) is cross-linked so that it is more closely localized in the vicinity of the surface layer of the shell layer.   The dye-colored polymer spherical particles having a shell-core structure have an average particle size of 0.1 to 0.1 on a volume basis in which the shell layer is formed on core particles having an average particle size of 0.05 to 40 μm on a volume basis. 2. Solvent fading-resistant dye-colored polymer spherical particles according to claim 1, characterized in that it is -50 [mu] m.   The solvent-bleachable dye-colored polymer spherical particles according to claim 1 or 2, wherein the dye is an achromatic black oil-soluble dye and / or a chromatic oil-soluble dye. The core particles, in which oil-soluble dyes are encapsulated and colored by the polymerization reaction coloring method in an aqueous emulsion system, are more closely localized in the surface layer of the shell layer, which is a (meth) acrylic polymer. In the method for producing dye-colored polymer spherical particles of a (meth) acrylic polymer having a shell-core structure that is cross-linked and excellent in solvent fading resistance,
The (meth) acrylic monomer has an oil-soluble dye and a molecular structure that is more hydrophilic than the (meth) acrylic monomer.

The raw material solution is prepared by dissolving the crosslinking agent represented by
Next, after adding a predetermined amount of water, a predetermined amount of emulsifier and a predetermined amount of polymerization initiator under stirring to prepare an aqueous emulsified solution, the organic polymer spherical core particles prepared in advance under stirring are prepared. Add a predetermined amount of suspension, expressed as solids concentration and dispersed at 5-40% concentration,
Next, dye-encapsulated polymer-colored polymer spheres having resistance to fading, characterized by dye-encapsulated coloring, shell layer polymerization formation, shell layer crosslinking, and aging while heating in a multi-step temperature range of 40 to 95 ° C. with stirring Particle production method.   When preparing the raw material solution, 1 to 50 parts by weight of the oil-soluble dye and 5 to 50 parts by weight of the crosslinking agent are dissolved per 100 parts by weight of the (meth) acrylic monomer. In preparing the aqueous emulsion solution, 50 to 500 parts by weight of water, a predetermined amount of emulsifier and a predetermined amount of polymerization initiator are added per 100 parts by weight of the (meth) acrylic monomer. After that, 1 to 50 parts by weight of the suspension in which the polymer spherical particles for core particles are dispersed is added, The method for producing solvent-bleachable dye-colored polymer spherical particles according to claim 4. The average particle size of the spherical core particles prepared in advance is 0.05 to 40 μm on a volume basis, and the average particle size of the obtained dye-colored polymer spherical particles is 0.1 to 50 μm on a volume basis. 6. The method of producing solvent-bleachable dye-colored polymer spherical particles according to claim 4 or 5, wherein the shell layer is formed so as to satisfy the following conditions.