JP2008231306A - Colored resin particle and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a colored resin particle having a coloring agent localized on a particle surface layer by a simple way. <P>SOLUTION: This method for manufacturing the colored resin particle comprises subjecting, to a suspension polymerization, a polymerizable monomer composition comprising a polymerizable monomer of 100 pts.wt., a polymer of 0.5-50 pts.wt. soluble in the polymerizable monomer, a silicon macromonomer of 0.1-20 pts.wt., and a pigment, in an aqueous solvent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to colored resin particles and a method for producing the same. More specifically, the present invention relates to a colored resin particle having a pigment localized in a particle surface layer and a method for producing the same.

  Colored resin particles obtained by dispersing and blending various pigments typified by titanium oxide in various resin materials are widely used, for example, as paints, additives for imparting design properties of resin moldings, and raw materials for electrophotographic toners. It has been.

  As a method for producing such colored resin particles, a pigment component is blended with a resin material, melt-kneaded after melt-kneading to obtain colored resin particles, a pigment component is dispersed and blended in a polymerizable monomer, A suspension polymerization method for producing colored resin particles by suspension polymerization in an aqueous medium is known.

Among these, the suspension polymerization method has been used frequently in recent years because particles having a relatively uniform particle size distribution and a spherical shape can be obtained.
Many pigments, including titanium oxide, increase in degree of coloring when the pigment content in the colored resin particles is increased. However, since the specific gravity of titanium oxide is heavier than that of the resin component, increasing the amount thereof increases the specific gravity of the colored resin particles. As a result, when the colored resin particles are blended with a solution such as a paint, the particles are likely to settle with time, and the stability with time deteriorates.

  In order to eliminate this defect, it is conceivable to localize the pigment in the particle surface layer. That is, even if the pigment content of the entire particle is the same amount, an improvement in the coloring degree of the particle can be expected if it can be localized. In addition, since the pigment content inside the particles can be reduced, it is expected that the temporal stability of the paint can be improved by reducing the specific gravity of the particles.

  Japanese Unexamined Patent Publication No. 4-370160 (Patent Document 1) is known as a method for producing particles in which a colorant is localized in the particle surface layer. This publication describes a method for producing colored resin particles in which carbon black is localized on the particle surface side for the purpose of improving the blackness and the affinity between the resin and the binder. In this publication, carbon black is used as a particle surface layer by using a carbon black graft polymer and using a polymer whose solubility parameter is larger than the monomer component constituting the particle or the solubility parameter of the polymer. Is localized.

  Japanese Patent Application Laid-Open No. 9-106106 (Patent Document 2) has a purpose of obtaining a high image density with a small amount of toner consumption and uses a carbon black graft polymer so that the colorant is compared with the toner central part. There is described a toner for an electrostatic charge image phenomenon that is densely dispersed in a surface layer.

  In addition, as colored resin particles containing a macromonomer, Japanese Patent Application Laid-Open No. 3-136005 (Patent Document 3) discloses static polymerization by suspension polymerization of a polymerizable monomer containing a colorant in the presence of a macromonomer. A method for obtaining a toner for charge image phenomenon is described.

JP-A-4-370160 JP 9-106106 A Japanese Patent Laid-Open No. 3-136005

  However, the methods described in Patent Documents 1 and 2 require a pretreatment for grafting a polymer to a colorant. Therefore, it is not a simple production method because the production process becomes complicated and it is necessary to set optimum grafting conditions according to the colorant.

  Furthermore, the method described in Patent Document 3 has a problem that the colorant is unevenly distributed in the particles. The inventors of the present invention speculate that this is because the use of silicon macromonomer reduces the stability of the colorant in the oil droplets during polymerization.

Thus, according to the present invention, 0.5 to 50 parts by weight of the polymer soluble in the polymerizable monomer, 0.1 to 20 parts by weight of the silicon macromonomer, and 100 parts by weight of the polymerizable monomer There is provided a method for producing colored resin particles, wherein a polymerizable monomer composition containing a pigment is subjected to suspension polymerization in an aqueous medium.
Furthermore, according to the present invention, 0.5 to 50 parts by weight of the polymer soluble in the polymerizable monomer and 0.1 to 20 parts by weight of the silicon macromonomer with respect to 100 parts by weight of the polymerizable monomer. And a colored resin particle obtained by suspension polymerization of a polymerizable monomer composition containing a pigment in an aqueous medium, wherein the colored resin particle has a particle surface layer in which the pigment is localized. A colored resin particle is provided.

  According to the present invention, the coloring agent is localized on the particle surface layer, and colored resin particles having excellent coloring degree can be easily obtained. Moreover, since the colored resin particle obtained by this invention is excellent in coloring degree, it can reduce pigment content. Furthermore, since the pigment content can be reduced, the specific gravity of the colored resin particles can be reduced. As a result, when colored resin particles are dispersed in a solution, the dispersion stability over time in the solution can be improved.

The term “particle surface layer” used in the present invention, as shown in FIG. 1, is a surface within a layer thickness range of 4 to 15% of the particle diameter of the resin from the surface of the colored resin particles. Means layer. Further, the term “pigments are localized in the particle surface layer” means a state where most of all pigments of the colored resin particles are present in the particle surface layer, as shown in FIG.
The polymerizable monomer used in the present invention is not particularly limited as long as suspension polymerization is possible, and various commonly used vinyl monomers can be used.

  Examples of such vinyl monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, Styrene monomers such as o-chlorostyrene, m-chlorostyrene, p-chlorostyrene; methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, cyclohexyl acrylate, acrylic acid n-octyl, dodecyl acrylate, 2-ethylhexyl acrylate, tetrahydrofurfuryl acrylate, stearyl acrylate, glycidyl acrylate, trifluoroethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, acrylic acid 2- Droxybutyl, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacryl Cyclohexyl acid, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, tetrahydrofurfuryl methacrylate, stearyl methacrylate, glycidyl methacrylate, trifluoroethyl methacrylate, 2-hydroxyethyl methacrylate, 2-methacrylic acid 2- Hydroxypropyl, 2-hydroxybutyl methacrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, dimethylamino methacrylate (Meth) acrylic acid ester monomers such as noethyl and diethylaminoethyl methacrylate; acrylic acid, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, methacrylic acid, 2-methacryloyloxy Examples include ethyl succinic acid, 2-methacryloyloxyethyl hexahydrophthalic acid, vinyl chloride, vinyl acetate, acrylonitrile, acrylamide, methacrylamide, N-vinyl pyrrolidone and the like. These vinyl monomers can be used alone or in combination of two or more. In addition, (meth) acryl means acryl or methacryl.

  For example, when using colored resin particles as an additive for imparting design properties to paints and resin moldings, the main component is a (meth) acrylic acid ester monomer in terms of weather resistance and heat resistance. Is preferred. The main component means 50% by weight or more of the total monomer amount.

  In addition, for the purpose of imparting solvent resistance, for example, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane triacrylate as crosslinking agents. Diethylenically unsaturated carboxylic acid esters such as acrylate, allyl methacrylate, t-butylaminoethyl methacrylate, tetraethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, N, N-divinylaniline, divinyl ether, divinyl sulfide, It is also possible to copolymerize all divinyl compounds of divinyl sulfonic acid and compounds having three or more vinyl groups.

Further, when the colored resin particles according to the present invention are used as a toner, those containing a styrene monomer and / or a (meth) acrylic acid ester monomer as a main component can be preferably used.
As the pigment used in the present invention, pigments well known to those skilled in the art can be used. For example, any of organic pigments, inorganic pigments, or a mixture thereof can be used.

  Examples of inorganic pigments include titanium oxide, alumina, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, and cerium oxide. , Bengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silica fine powder, silicon carbide, silicon nitride, boron carbide, tungsten carbide, titanium carbide, cerium oxide and the like.

  Examples of organic pigments include yellows such as Navels Yellow, Naphthol Yellow S, Hanser Yellow G, Hanser Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, and condensed azo. Pigments, orange pigments such as Kiribden Orange, Permanent Orange RK, Benzidine Orange G, Indanthrene Brilliant Orange GK, Permanent Red 4R, Resor Red, Pyrazolone Red 4R, Watching Red Calcium Salt, Lake Red D, Quinacridone, Anthraquinone, Brilliant Carmine 6B, Eomin Lake, Rhodamine Lake B, Buzarin Lake, Brilliant Carmine B, red pigments such as condensed azo, Fast Violet B, Methyl Purple pigments such as iolet lake, alkali blue lake, Victoria blue lake, copper phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partial chloride, fast sky blue, indanthrene blue BC and other blue pigments, pyrachite green lake, And green pigments such as chlorinated copper phthalocyanine green and final yellow green G.

  In order to obtain a magnetic toner, it is also possible to add, for example, a powder of a ferromagnetic metal such as iron, cobalt or nickel, or a powder of a magnetic metal compound such as magnetite, hematite or ferrite. is there. Since these magnetic powders also act as a colorant, these magnetic powders can be used as a colorant either alone or in combination with the above-described pigment when obtaining a magnetic toner.

  In the present invention, the blending amount of the pigment in the polymerizable monomer composition is not particularly limited, and also depends on the type of the colorant used, etc. The coloring agent is preferably 1 to 50 parts by weight, more preferably 3 to 30 parts by weight with respect to parts.

  If the colorant is less than 1 part by weight, the degree of coloration in the resulting colored resin particles will not be sufficient, while if it exceeds 50 parts by weight, the effect of increasing the amount of addition will not be seen so much. Since the specific gravity is increased, it is not preferable because it tends to settle in a solution such as a paint.

  The polymer soluble in the polymerizable monomer is used for the purpose of stabilizing the dispersion of the pigment in the polymerizable monomer composition, and if it is soluble in the polymerizable monomer, its type and Any molecular weight can be used.

  Whether the above polymer is soluble or insoluble in the polymerizable monomer, for example, the polymer is added to the polymerizable monomer, and a stirrer such as a homomixer at room temperature (25 ° C.). It can be easily judged by whether or not it becomes transparent.

There are the following methods for determining solubility in more detail.
That is, for example, 3 g of a polymer is precisely weighed (Ag), 100 g of a polymerizable monomer is added to this polymer, and the mixture is stirred at 25 ° C. for 24 hours using a rotary shaker (R-II manufactured by Taiyo Kagaku Kogyo). I do. Then, it filters using the funnel (Bg) which set the glass fiber filter paper (Advantech GF-75). After filtration, the funnel containing the filter paper is dried by heating at 60 ° C. for 24 hours, and the weight after drying is measured (Cg). Based on the weighed weight, the solubility of the polymer in the polymerizable monomer is determined using the following formula.

Solubility (% by weight) = [1-{(CB) / A}] × 100
In the present invention, the polymer is soluble in the polymerizable monomer when the solubility is 95% or more. In addition, a preferable solubility range is 95 to 100 weight%, More preferably, it is 99 to 100 weight%.

  Examples of the polymer used in the present invention include acrylic acid ester polymer, methacrylic acid ester polymer, styrene polymer, vinyl chloride polymer, vinyl acetate polymer, ethyl cellulose resin, rosin resin and the like. These polymers can be used alone or in combination of two or more. Moreover, you may use these copolymers. The polymer is preferably the same as the polymer obtained from the polymerizable monomer used in the present invention, more preferably the same type.

  The addition amount of the polymer soluble in the polymerizable monomer is, for example, preferably 0.5 to 50 parts by weight, more preferably 1 to 30 parts by weight with respect to 100 parts by weight of the polymerizable monomer. . When the polymer soluble in the polymerizable monomer is less than 0.5 part by weight, the dispersibility of the colorant in the polymerizable monomer composition becomes unstable, and the colorant is introduced into the aqueous medium during the polymerization. This is not preferable because it causes the generation of aggregated particles. On the other hand, if the amount exceeds 50 parts by weight, the effect of increasing the addition amount is not so much observed, and the polymerization of the polymerizable monomer composition may not proceed sufficiently.

  The present invention is characterized in that a polymer soluble in a polymerizable monomer and a silicon macromonomer are used in combination.

  The reason why the colored resin particles in which the colorant is localized in the particle surface layer is obtained by the combined use of the polymer soluble in the polymerizable monomer and the silicon macromonomer is not clear, but is as follows. The inventors have speculated. That is, the polymer soluble in the polymerizable monomer serves to stabilize the dispersion of the colorant in the polymerizable monomer. Further, it is presumed that as the polymerization proceeds, the silicon macromonomer undergoes microphase separation, and the colorant is pushed out to the particle surface layer.

Examples of the silicon macromonomer used in the present invention include the following formula:
(R ₁ and R ₃ are a hydrogen atom or a methyl group, R ₂ and R ₄ are a phenyl group, a methyl group, an ethyl group, or a butyl group, n is an integer of 10 to 400, and m is 1 or more. Is an integer)
The thing which has a structure shown by these is mentioned. n is more preferably 10 to 150, and m is more preferably 3 to 10. A mixture of two or more of the above silicon macromonomers may be used.

  It is preferable to use a silicon macromonomer having a molecular weight of about 400 to 50,000.

  Examples of more specific silicon macromonomers include, for example, one-end methacryloyl group-modified polymethyl methacrylate, one-end methacryloyl group-modified polyethyl methacrylate, one-end methacryloyl group-modified polybutyl methacrylate, and one-end methacryloyl group-modified polymethacrylate. Examples include octyl acid, one-terminal methacryloyl group-modified polydecyl methacrylate, and the like.

  The addition amount of the silicon macromonomer is, for example, preferably 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer.

  If the addition amount of the silicon macromonomer is less than 0.1 parts by weight, the colorant is difficult to localize in the particle surface layer, which is not preferable. On the other hand, if it exceeds 20 parts by weight, it is not preferable because the colorant is difficult to localize in the particle surface layer and tends to be unevenly distributed inside the particle.

  In the present invention, a polymerization initiator may be added to accelerate the polymerization of the polymerizable monomer.

  Examples of the polymerization initiator include polymerization initiators that are soluble in polymerizable monomers that have been used in conventional suspension polymerization.

  As polymerization initiators, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, cyclohexanone peroxide, t- Peroxide initiators such as butyl hydroperoxide and diisopropylbenzene 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-trimethylbutyronitrile), 2, 2′-azobis (2-isopropylbutyronitrile), 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.

  Among these, benzoyl peroxide, lauroyl peroxide, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile) are preferably used. These polymerization initiators may be used alone or in combination. The use ratio of the polymerization initiator is preferably about 0.01 to 1 part by weight with respect to 100 parts by weight of the polymerizable monomer.

  In the present invention, a dispersion stabilizer may be used. A well-known thing can be used as a dispersion stabilizer. For example, water-soluble polymer compounds such as methyl cellulose, hydroxyethyl cellulose, and polyvinyl alcohol, or poorly water-soluble inorganic salts such as tricalcium phosphate, magnesium hydroxide, magnesium pyrophosphate, and barium sulfate can be used.

  However, when a water-soluble polymer compound is used as a dispersion stabilizer, it is difficult to completely remove the stabilizer from the particle surface obtained after polymerization. Sometimes.

On the other hand, when a poorly water-soluble inorganic salt is used as the dispersion stabilizer, it is easy to remove the dispersion stabilizer from the particle surface obtained after polymerization. Therefore, the problem caused by the remaining dispersion stabilizer does not occur. Therefore, it is particularly preferable to use a hardly water-soluble inorganic salt as the dispersion stabilizer.
Although the usage-amount of a dispersion stabilizer is not specifically limited, Usually, it is 0.1-20 weight part per 100 weight part of colored resin particles finally obtained.

In the production method of the present invention, a surfactant may be further used.
The surfactant is not particularly limited, and those usually used in suspension polymerization in an aquatic medium can be used. For example, anionic surfactants, cationic surfactants, zwitterionic surfactants, nonionic surfactants and the like can be mentioned. Of these, anionic surfactants are preferred from the viewpoint of the stability of suspended particles.

  Examples of anionic surfactants include fatty acid oils such as sodium oleate and castor oil potassium, alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalene sulfonates. , Alkane sulfonate, dialkyl sulfosuccinate, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene alkyl sulfate, and the like. The amount of these used is not particularly limited, but is usually 0.005 to 0.3% by weight based on the aqueous medium.

In the production method of the present invention, coloring of carboxylic acid, sulfonic acid, sulfuric acid ester, phosphoric acid ester, phosphonic acid, and salts thereof, coupling agents such as silane, titanate, and aluminate, etc., as necessary An agent dispersant may be used. Moreover, you may use the coloring agent dispersing agent as described in patent 3816009 and patent 2872876.
The amount of the colorant dispersant added is preferably 1 to 20 parts by weight with respect to 100 parts by weight of the colorant.

Next, an example of the order of addition of the polymerizable monomer, pigment, polymer soluble in the polymerizable monomer, silicon macromonomer, polymerization initiator, dispersion stabilizer, and surfactant in the present invention will be described.
First, in the suspension polymerization method, a polymerizable monomer composition obtained by dispersing a pigment in a polymerizable monomer, a polymer soluble in the polymerizable monomer, a silicon macromonomer, and a polymerization initiator, Colored resin particles can be obtained by suspending in an aqueous medium and polymerizing.

  The order of adding the constituent components of the polymerizable monomer composition is not particularly limited. For example, the order in which the silicon macromonomer is added to the mixture in which the pigment is dispersed in the polymerizable monomer and then the polymer is dissolved, the colorant, the polymer, and the silicon macromonomer are simultaneously added to the polymerizable monomer. And the order in which the pigment is dispersed in the obtained mixture. Among these, the order of adding the master batch in which the pigment is dispersed in the polymer to the polymerizable monomer together with the silicon macromonomer is most preferable because the process is simplified.

  The apparatus for dispersing the pigment is not particularly limited. For example, a media type dispersion device such as a ball mill, an attritor, and a sand mill, a shear type dispersion device such as a homomixer, a homogenizer, and a biomixer, and an ultrasonic dispersion device are preferably exemplified.

The polymerizable monomer composition in which the pigment is dispersed is suspended in an aqueous medium. Here, examples of the aqueous medium include water or a mixture of water and a water-soluble organic solvent (for example, a lower alcohol).
The average particle diameter of the colored resin particles according to the present invention can be appropriately adjusted by adjusting the mixing conditions and stirring conditions of the polymerizable monomer composition and the aqueous medium.
The average particle size can be reduced by increasing the amount of the aqueous medium for the polymerizable monomer composition, increasing the amount of the surfactant, increasing the stirring speed, or increasing the stirring time.

  In order to stabilize the suspended particles, it is preferable to use 0.1 to 30 parts by weight of a dispersion stabilizer in 100 parts by weight of the polymerizable monomer composition in the aqueous medium. The dispersion stabilizer is preferably added to the aqueous medium before the addition of the polymerizable monomer composition.

  In order to disperse the polymerizable monomer composition in the aqueous medium with fine droplets, for example, a stirring method such as a propeller blade, a general homogenizer that is a disperser using a high shear composed of a rotor and a stator. Examples include a method using a mixer, a method using an ultrasonic disperser, a method using a high-pressure disperser using a collision force against a machine wall such as a microfluidizer or a nanomizer, or a collision force between droplets.

  Next, the polymerization reaction can be started by suspending the polymerizable monomer composition and the aqueous medium and then raising the temperature while stirring. The stirring speed at this time is preferably a speed that can prevent oil droplets from floating and particles after polymerization.

  The polymerization start temperature is preferably 40 to 90 ° C. And it is preferable to make it superpose | polymerize generally about 1 to 10 hours, hold | maintaining at this temperature. Thereafter, the polymerization temperature may be about 95 to 120 ° C., and the polymerization reaction may be completed in about 0.1 to 5 hours.

After the completion of the polymerization reaction, the obtained colored resin particles are separated from the aqueous medium, washed and dried by a conventional method, and then subjected to a classification step as necessary to obtain a desired particle size, for example, an average particle size of 0.5. Colored resin particles of ˜100 μm, more preferably 1-20 μm can be obtained.
The resulting colored resin particles are used in the chemical field such as paints, inks and adhesives such as matting agents, the cosmetics field such as slip agents and extender pigments, the electronic industry field such as electrophotographic toners and LCD spacers, light diffusing agents, It can be used in general industrial fields such as resin modifiers.

  Hereinafter, the present invention will be described more specifically with reference to examples. In the following description, “part” means part by weight and “%” means weight% unless otherwise specified.

  The average particle diameter of the colored resin particles, the dispersion state of the colorant in the colored resin particles, and the degree of coloring are measured by the following methods.

(Average particle size)
The average particle diameter is a value obtained by measurement with Multisizer II. According to REFERENCE MANUAL FOR THE COULTER MULTISIZER (1987) published by Coulter Electronics Limited, an aperture is selected according to the particle size, and calibration is performed for measurement.

  Specifically, 0.1 g of resin particles are predispersed in 10 ml of a 0.1% nonionic surfactant solution using a touch mixer and ultrasonic waves, and this is provided with ISOTON II (manufactured by Beckman Coulter, Inc .: In a beaker filled with the electrolyte for measurement), drop gently with a dropper while stirring gently, and adjust the concentration meter reading on the main body screen to around 10%. Next, when the aperture size is 100 μm in the Multisizer II body, Current is input as 1600, Gain as 2, and Polarity as +, and measurement is performed manually. During the measurement, the beaker is stirred gently to the extent that bubbles do not enter, and the measurement is terminated when 100,000 particles are measured.

(Confirmation of colorant dispersion in colored resin particles)
Colored resin particles are embedded in an epoxy resin, an ultrathin section is prepared, and a cross section is observed with a transmission electron micrograph.
As the transmission electron microscope apparatus, for example, “H-7600” manufactured by Hitachi, Ltd. can be used.

(Coloring degree)
The coloring degree of the colored resin particles is measured by the following method.
(1) Preparation of paint In 70 parts of solvent containing toluene, ethyl acetate, and butyl acetate in a weight ratio of 70:20:10, 30 parts of acrylic resin (Mitsubishi Rayon Co., Ltd. Dianar BR-106) is dissolved to form a binder solution. To do.
6 parts of colored resin particles are weighed in 50 parts of the above binder solution in a 100 ml plastic container, and dispersed using a stirring defoaming machine (Shinky Awatori Nertaro) under conditions of stirring time of 3 minutes and defoaming time of 30 seconds. And paint.

(2) Preparation of coating film A coating material is prepared by coating a coating material on a substrate made of a PET film using a coater having a squeegee of 50 μm, and drying in a constant temperature dryer at 70 ° C. for 10 hours after coating.
(3) Coloring degree evaluation Using a color difference meter (CR-300 manufactured by Minolta Co., Ltd.), the color difference of the coating film placed on the black plate is measured in the Lab color specification mode to obtain an L value as the coloring degree.

Example 1
90 parts of methyl methacrylate, 10 parts of diethylene glycol dimethacrylate, 5 parts of silicon macromonomer having a number average molecular weight of 1000 (Silane Plain FM-0711 manufactured by Chisso Corporation), acetoalkoxyaluminum diisopropylate (Plenact AL-M manufactured by Ajinomoto Fine Techno Co., Ltd.) 0.3 parts, 10 parts of polymethyl methacrylate (solubility: 100%), and 10 parts of titanium oxide (JR600A manufactured by Teika) as a white pigment are weighed, and 15 parts at 8000 rpm using a homomixer (manufactured by Special Machine Industries). A polymerizable monomer composition was prepared by dispersing for a minute. Here, 0.3 part of 2,2′-azobisisobutyronitrile, 0.2 part of benzoyl peroxide and lauryl phosphoric acid (Phosten HLP manufactured by Nikko Chemical Co., Ltd.) are added and dissolved in the polymerizable monomer composition. did. Next, it is put into 600 parts of water in which 0.02% sodium dodecylbenzenesulfonate and 2% magnesium pyrophosphate prepared in advance are dispersed, and stirred at 5000 rpm for 3 minutes using a homomixer (manufactured by Tokushu Kika Co., Ltd.). To obtain a suspension.

The suspension was heated with uniform stirring so that the suspension did not settle under a nitrogen atmosphere, and polymerization was carried out at 60 ° C. for 8 hours. Furthermore, the temperature was raised to 100 ° C. and polymerization was continued for 2 hours.
Next, after cooling to room temperature and adding hydrochloric acid to dissolve magnesium pyrophosphate as a suspension stabilizer, solid-liquid separation and water washing were repeated, followed by drying in a hot air dryer at 70 ° C. for 24 hours, classification. Thus, colored resin particles were obtained.

  The average particle diameter of the obtained colored resin particles was 5.7 μm. As a result of observing the dispersion state of titanium oxide inside the colored resin particles with a transmission electron microscope (magnification 22500 times), it was observed that the titanium oxide was localized in the particle surface layer as shown in FIG.

Comparative Example 1
Colored resin particles were obtained in the same manner as in Example 1 except that no silicon macromonomer was used.
The average particle diameter of the obtained colored resin particles was 5.6 μm. As a result of observing the dispersion state of the titanium oxide in the colored resin particles with a transmission electron microscope (magnification 16100 times), it was not observed that the titanium oxide was localized in the particle surface layer as shown in FIG. .

Comparative Example 2
Colored resin particles were obtained in the same manner as in Example 1 except that the silicon macromonomer was 30 parts.
The average particle diameter of the obtained colored resin particles was 6.2 μm. As a result of observing the dispersion state of the titanium oxide inside the colored resin particles with a transmission electron microscope, it was not observed that the titanium oxide was partially unevenly distributed inside the particles and localized in the particle surface layer.

Example 2
90 parts of methyl methacrylate, 10 parts of diethylene glycol dimethacrylate, 5 parts of silicon macromonomer (Silane Plain FM-0711 manufactured by Chisso), vinyl chloride-vinyl acetate copolymer (Solvine C5 manufactured by Nissin Chemical Industry Co., Ltd.) , 3 parts of solubility), 14 parts of titanium oxide (Microlith White RK manufactured by Ciba Specialty Chemicals Co., Ltd.), a white pigment, was weighed and dispersed at 8000 rpm for 15 minutes using a homomixer (manufactured by Special Machinery Corporation) To prepare a polymerizable monomer composition. Here, 0.3 part of 2,2′-azobisisobutyronitrile and 0.2 part of benzoyl peroxide were added and dissolved in the polymerizable monomer composition. Next, 600 parts of water in which 0.02% sodium dodecylbenzenesulfonate and 2% magnesium pyrophosphate prepared in advance are dispersed is added and stirred at 5000 rpm for 3 minutes using a homomixer (manufactured by Tokushu Kika Co., Ltd.). To obtain a suspension.

  The suspension was heated with uniform stirring so that the suspension did not settle under a nitrogen atmosphere, and polymerization was carried out at 60 ° C. for 8 hours. Furthermore, the temperature was raised to 100 ° C. and polymerization was continued for 2 hours.

Next, after cooling to room temperature and adding hydrochloric acid to dissolve magnesium pyrophosphate as a suspension stabilizer, solid-liquid separation and water washing were repeated, followed by drying in a hot air dryer at 70 ° C. for 24 hours, classification. Thus, colored resin particles of the present invention were obtained.
The average particle diameter of the obtained colored resin particles was 5.2 μm. As a result of observing the dispersion state of titanium oxide inside the colored resin particles with a transmission electron microscope, it was observed that the titanium oxide was localized in the particle surface layer.

Comparative Example 3
Colored resin particles were obtained in the same manner as in Example 1 except that polymethyl methacrylate was not used.
The average particle diameter of the obtained colored resin particles was 5.9 μm. As a result of observing the dispersion state of titanium oxide in the colored resin particles with a transmission microscope, it was found that the titanium oxide was partially unevenly distributed in the particles and localized in the particle surface layer.

Example 3
Number average molecular weight using 10 parts of magenta pigment (Microlith Magenta 5B-K, Ciba Specialty Chemicals Co., Ltd., 40% vinyl chloride-vinyl acetate copolymer resin) instead of 14 parts of white oxide titanium oxide Colored resin particles were obtained in the same manner as in Example 2 except that 3 parts of silicon macromonomer (Silane Plan FM-0721 manufactured by Chisso Corporation) was used instead of 5 parts of 1000 silicon macromonomer.
The average particle diameter of the obtained colored resin particles was 5.5 μm. As a result of observing the dispersion state of the magenta pigment in the colored resin particles with a transmission electron microscope, it was observed that the magenta pigment was localized in the particle surface layer.

Example 4
Colored resin particles were obtained in the same manner as in Example 1 except that 25 parts of polymethyl methacrylate and 8 parts of silicon macromonomer were replaced.
The average particle diameter of the obtained colored resin particles was 6.8 μm. As a result of observing the dispersion state of titanium oxide inside the colored resin particles with a transmission electron microscope, it was observed that the titanium oxide was localized in the particle surface layer.

Comparative Example 4
Colored resin particles were obtained in the same manner as in Example 1 except that polyethylene wax was used instead of polymethyl methacrylate.
The average particle diameter of the obtained colored resin particles was 6.5 μm. As a result of observing the dispersion state of titanium oxide in the colored resin particles with a transmission microscope, it was found that the titanium oxide was partially unevenly distributed in the particles and localized in the particle surface layer.

Example 5
85 parts of methyl methacrylate, 15 parts of diethylene glycol dimethacrylate, 0.5 parts of silicon macromonomer having a number average molecular weight of 5000 (Chiraso Silaplane FM-0721), acetoalkoxyaluminum diisopropylate (Plainact AL-manufactured by Ajinomoto Fine Techno Co., Ltd.) M) 0.1 part, 1 part of polymethyl methacrylate (solubility 100%), 2 parts of carbon black (MA-100 manufactured by Mitsubishi Chemical Corporation) as a black pigment were weighed and mixed, and a homomixer (specialized machinery company) And then dispersed in a 500 ml container with 100 g of 1.5 mm glass beads, dispersed and mixed for 20 minutes in a desktop sand mill, and then all of the glass beads are removed to form a polymerizable monomer composition. A product was prepared. Here, 0.3 part of 2,2′-azobisisobutyronitrile, 0.2 part of benzoyl peroxide and 0.1 part of lauryl phosphoric acid (Phosten HLP manufactured by Nikko Chemical Co., Ltd.) were added to the polymerizable monomer composition. And dissolved. Next, it is put into 600 parts of water in which 0.02% sodium dodecylbenzenesulfonate and 3% magnesium pyrophosphate prepared in advance are dispersed, and stirred at 5000 rpm for 3 minutes using a homomixer (manufactured by Tokushu Kika Co., Ltd.). To obtain a suspension.

The suspension was heated with uniform stirring so that the suspension did not settle under a nitrogen atmosphere, and polymerization was carried out at 60 ° C. for 8 hours. Furthermore, the temperature was raised to 100 ° C. and polymerization was continued for 2 hours.
Next, after cooling to room temperature and adding hydrochloric acid to dissolve magnesium pyrophosphate as a suspension stabilizer, solid-liquid separation and water washing were repeated, followed by drying in a hot air dryer at 70 ° C. for 24 hours, classification. Thus, colored resin particles were obtained.

The average particle diameter of the obtained colored resin particles was 4.7 μm. As a result of observing the dispersion state of the carbon black inside the colored resin particles with a transmission electron microscope, it was observed that the carbon black was localized in the particle surface layer.
The L values of the above Examples and Comparative Examples were measured, and the results are shown in Table 1.

  From the results of Table 1, it can be seen that the coating film containing the colored resin particles obtained by the production method of the present invention has a high L value representing whiteness and is excellent in coloring effect.

2 is a transmission electron micrograph of colored resin particles obtained in Example 1. FIG. 2 is a transmission electron micrograph of colored resin particles obtained in Comparative Example 1.

Claims (2)

  Polymerization containing 0.5 to 50 parts by weight of a polymer soluble in the polymerizable monomer, 0.1 to 20 parts by weight of a silicon macromonomer, and a pigment with respect to 100 parts by weight of the polymerizable monomer A method for producing colored resin particles, comprising subjecting a polymerizable monomer composition to suspension polymerization in an aqueous medium.   Polymerization containing 0.5 to 50 parts by weight of a polymer soluble in the polymerizable monomer, 0.1 to 20 parts by weight of a silicon macromonomer, and a pigment with respect to 100 parts by weight of the polymerizable monomer Colored resin particles obtained by suspension polymerization of a polymerizable monomer composition in an aqueous medium, wherein the colored resin particles have a particle surface layer in which pigments are localized particle.