JP5949698B2 - Method for producing organic resin particles - Google Patents

Description

  The present invention relates to an inorganic dispersion stabilizer for suspension polymerization, and a method for producing organic resin particles using the same. The present invention is a dispersion stabilizer for suspension polymerization that can improve the stability during suspension polymerization, and by using this, the particle size distribution is narrow, and the obtained organic resin particles are taken out as dry particles. It is possible to obtain organic resin particles with excellent fluidity at the time, no adhesion and coalescence of particles, good environmental characteristics, and excellent redispersibility when dispersion in liquid is necessary The present invention relates to a method for producing organic resin particles. Furthermore, the present invention relates to a method for producing organic resin particles useful as a negatively charged electrostatic image developing toner, and an electrostatic image developing toner using the organic resin particles.

  In electrophotography, an electrical latent image is formed on a photoreceptor composed of an inorganic photoconductor material such as selenium, zinc oxide, cadmium sulfide, or an organic photoconductor material, and this is developed with a powder developer. It is transferred to paper and fixed.

  Conventionally, toner used for electrophotographic development is generally obtained by melting and dispersing a colorant and other additives (charge control agent, anti-offset agent, lubricant, etc.) in a thermoplastic resin, and then solidifying the resulting mixture. The product was pulverized and classified to produce colored fine particles having a desired particle size.

  However, the above-described method for producing toner by pulverization has various drawbacks. First, a process for producing a resin, a process for kneading a resin with a colorant and other additives, a process for pulverizing a solid, a process for classifying the pulverized product to obtain colored fine particles having a desired particle size, etc. Therefore, many processes and various devices associated therewith are required, and the toner produced by this method is inevitably expensive. In particular, in order to obtain a toner having an optimum particle size range for forming a clear image with little fogging, the classification step is an essential requirement, but there is a problem in productivity and yield. Secondly, it is extremely difficult for the colorant and other additives to be uniformly dispersed in the resin in the kneading step. Therefore, the toner produced by this method has poor dispersion of the colorant, charge control agent, and the like. However, the triboelectric charging characteristics of each particle are different, which leads to a decrease in resolution. Such a problem will become more prominent as the toner particle size becomes an essential condition for improving the image quality in the future. In other words, the current pulverizer has a limit in obtaining a toner having a small particle diameter, and even if a toner having a small particle diameter is obtained, the dispersion of the colorant and the charge control agent is poor, so that the variation in charge amount is larger. Occurs.

  In order to improve various drawbacks observed in the toner produced by these pulverization methods, a toner production method using a monomer suspension polymerization method has been proposed.

  These methods are methods in which a colorant substance such as carbon black and other additives are added to a polymerizable monomer and subjected to suspension polymerization to synthesize resin toner particles containing the colorant substance all at once. By this method, it is possible to considerably improve the disadvantages of the conventional grinding method. That is, since the pulverization step is not included at all, improvement in brittleness is not necessary, and since the shape is spherical and the fluidity is excellent, the triboelectric chargeability is uniform.

  However, in the production of resin particles by such a suspension polymerization method, polymerization is carried out in a stably suspended system in which the droplets of the monomer composition are not coalesced, and a uniform particle size is obtained by polymerization. Obtaining fine resin particles having a distribution is technically difficult.

  Therefore, when the polymerizable monomer composition is subjected to suspension polymerization in an aqueous medium, a dispersion stabilizer is conventionally used in order to prevent coalescence of polymer particles as the polymerization proceeds.

As the dispersion stabilizer, conventionally, an insoluble finely divided inorganic compound such as BaSO ₄ , CaSO ₄ , MgCO ₃ , BaCO ₃ , CaCO ₃ , Ca ₃ (PO ₄ ) ₂ , hardly soluble salts, diatomaceous earth, etc. Inorganic polymers such as talc, silicic acid, and clay, powders of metal oxides, or water-soluble polymers such as polyvinyl alcohol, gelatin, and starch are used (Patent Documents 1 and 2).

  However, when a poorly water-soluble inorganic substance is used as a dispersion stabilizer, there is a possibility that the particle size distribution of the obtained polymer particles may be relatively narrow, but when trying to obtain a desired particle size of about 2 to 30 μm. Due to the relatively large amount used and the surfactant (emulsifier) used as a dispersion stabilizing aid, there are problems in controlling the particle size distribution, such as the generation of fine particles caused by concurrent emulsion polymerization. It was. Furthermore, there has been a drawback that an operation of removing the dispersion stabilizer by the pickling and / or water washing treatment after the polymerization step is necessary, and if this is insufficient, there is a problem that the electrical characteristics are deteriorated.

  On the other hand, when a water-soluble polymer is used as the dispersion stabilizer, the resin particles obtained by suspension polymerization of the monomer contain many particles having a small particle size, so that the particle size distribution is wide. Therefore, in order to obtain resin particles having a narrow particle size distribution, a plurality of complicated operations such as classification are required. In addition, since it is difficult to remove the dispersion stabilizer attached to the surface of the resin particles, there are disadvantages in that electrical characteristics are extremely deteriorated and adhesion and coalescence of particles occur.

  The use of a hydrophobic inorganic oxide (hydrophobic silica) as an improvement of the above dispersion stabilizer is also disclosed in Patent Document 3, but the above dispersion stabilizer (a poorly water-soluble inorganic substance and a water-soluble polymer) is disclosed. Resin particles can be produced better than the above), but the dispersion of hydrophobic silica shape and particle size distribution also varies the particle size distribution and particle shape of the produced organic resin particles, and the performance of the organic resin particles. There is a drawback that a problem occurs.

JP-A-63-198075 JP-A-4-127162 Japanese Patent No. 4704317

  Accordingly, an object of the present invention is to provide a method for producing organic resin particles using novel hydrophobic spherical silica particles as a dispersion stabilizer in the production of organic resin particles by suspension polymerization of monomers. It is.

  The present invention also provides a hydrophobic spherical silica particle dispersion stabilizer capable of improving the stability during suspension polymerization, and a narrow particle size distribution by using the same, and the obtained organic resin particles are used as dry particles. Excellent fluidity when taken out, no adhesion and coalescence of particles, good environmental characteristics, and when it is necessary to disperse in liquid, obtain organic resin particles with excellent redispersibility It aims at providing the manufacturing method of the resin particle which can be used.

  Furthermore, since the present invention has a narrow particle size distribution, the classification process can be simplified, the yield is high and the productivity is excellent, and when used as an electrostatic image developing toner, the particle size distribution is extremely narrow and good. Resin capable of obtaining organic resin particles useful as a negatively charged electrostatic charge image developing toner having excellent image characteristics such as stable image, good reproducibility of fine lines, and no fogging based on electrical characteristics It aims at providing the manufacturing method of particle | grains.

  As a result of intensive studies to solve the above problems, the present inventors have reached the present invention.

The object is to disperse a monomer composition containing a polymerizable monomer in the presence of a dispersion stabilizer obtained by dispersing hydrophobic spherical silica particles in an aqueous medium in the presence of a hydrophilic organic compound, It is achieved by a method for producing organic resin particles characterized by polymerizing.
Specifically, the present application includes the following <1> to <12> inventions.

  <1> A monomer composition containing a polymerizable monomer is subjected to suspension polymerization in the presence of a dispersion stabilizer obtained by dispersing hydrophobic spherical silica particles in an aqueous medium in the presence of a hydrophilic organic compound. The silica resin particles having a particle diameter (volume-based median diameter) in the range of 0.005 to 1.00 μm (5 to 1000 nm) and a particle size distribution D90 / D10 of 3. A method for producing organic resin particles, comprising hydrophobic spherical silica particles having an average circularity of 0.8 to 1 and a hydrophobicity of 60% or more.

<2> The hydrophobic spherical silica particles are
(A1) a step of obtaining hydrophilic spherical silica particles substantially consisting of SiO ₂ units by hydrolyzing and condensing a tetrafunctional silane compound, a partially hydrolyzed condensation product thereof, or a mixture thereof;
(A2) R ¹ SiO _3/2 units (wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms) are introduced onto the surface of the hydrophilic spherical silica particles. Process,
(A3) Further, R ² ₃ SiO _1/2 units (wherein each R ² is the same or different and is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms) on the surface of the hydrophilic spherical silica particles. The method for producing organic resin particles according to <1>, wherein the method comprises the step of introducing

<3> The hydrophobic spherical silica particles are
(A1) General formula (I):
Si (OR ³ ) ₄ (I)
(Wherein each R ³ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms), a tetrafunctional silane compound, a partial hydrolysis product thereof, or a mixture thereof, In the presence of the substance, a mixed solvent dispersion of hydrophilic spherical silica particles substantially consisting of SiO ₂ units is obtained by hydrolysis and condensation in a mixed liquid of a hydrophilic organic solvent and water,
(A2) In the mixed solvent dispersion of the obtained hydrophilic spherical silica particles, the general formula (II):
R ¹ Si (OR ⁴ ) ₃ (II)
Wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and each R ⁴ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms. trifunctional silane compound, a partial hydrolysis product, or by treating the surface of the hydrophilic spherical silica particles was added to these mixtures, the surface of the hydrophilic spherical silica particles R ¹ SiO 3 _{/ 2} units (R ¹ is as described above) were introduced to obtain a mixed solvent dispersion of the first hydrophobic spherical silica particles,
(A3) To the resulting mixed solvent dispersion of the first hydrophobic spherical silica particles, the general formula (III):
R ² ₃ SiNHSiR ² ₃ (III)
(In the formula, each R ² is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms)
A silazane compound represented by the general formula (IV):
R ² ₃ SiX (IV)
(Wherein R ² is as defined in formula (III) and X is an OH group or a hydrolyzable group), or a mixture thereof, The surface of the first hydrophobic spherical silica particles is treated with the silazane compound, the monofunctional silane compound, or a mixture thereof, and the surface of the first hydrophobic spherical silica fine particles is R ² ₃ SiO _1/2. <1> or <2>, which is a hydrophobic spherical silica particle obtained as a second hydrophobic silica particle by introducing a unit (R ² is as defined in formula (III)) Manufacturing method of organic resin particles.

  <4> The method for producing organic resin particles according to <2> or <3>, including a concentration step between the production steps (A2) and (A3) of the silica particles.

  <5> The obtained organic resin particles have a volume average particle size of 0.1 to 500 μm and a particle size distribution (ratio of volume average particle size / number average particle size) of 1.6 or less. The manufacturing method of the organic resin particle as described in <1>-<4>.

  <6> The monomer composition is a composition containing a polymerizable monomer and at least one selected from a (co) polymer, a colorant, and other additives. <1>-<5> The manufacturing method of the organic resin particle as described in <5>.

  <7> The method for producing organic resin particles according to <6>, wherein the monomer composition is a composition containing a polymerizable monomer and a colorant.

  <8> An electrostatic charge image developing toner comprising the colored organic resin particles produced by the production method according to <7>.

  <9> A dispersion stabilizer for suspension polymerization of a polymerizable monomer, wherein the hydrophobic spherical silica particles are dispersed in an aqueous medium in the presence of a hydrophilic organic compound, the hydrophobic spherical silica particles However, the particle diameter (volume-based median diameter) is in the range of 0.005 to 1.00 μm (5 to 1000 nm), the value of the particle size distribution D90 / D10 is 3 or less, and the average circularity is 0.8 to 1. A dispersion stabilizer for suspension polymerization of a polymerizable monomer, characterized in that it is hydrophobic spherical silica particles having a hydrophobization degree of 60% or more.

<10> The hydrophobic spherical silica particles are
(A1) a step of obtaining hydrophilic spherical silica particles substantially consisting of SiO ₂ units by hydrolyzing and condensing a tetrafunctional silane compound, a partially hydrolyzed condensation product thereof, or a mixture thereof;
(A2) R ¹ SiO _3/2 units (wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms) are introduced onto the surface of the hydrophilic spherical silica particles. Process,
(A3) Further, R ² ₃ SiO _1/2 units (wherein each R ² is the same or different and is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms) on the surface of the hydrophilic spherical silica particles. The dispersion stabilizer for suspension polymerization of a polymerizable monomer according to <9>, wherein the dispersion stabilizer is produced by a method comprising a step of introducing

  <11> The dispersion stabilizer according to <9> or <10>, wherein the hydrophilic organic compound is an alcohol having 1 to 3 carbon atoms.

  <12> The dispersion stabilizer according to <9> to <11>, wherein the aqueous medium is water or a water / alcohol mixture.

  The organic resin particles obtained by the production method according to the present invention have a very narrow particle size distribution, excellent fluidity when dried and taken out as particles, no adhesion and coalescence of particles, and good environmental characteristics. . When used as an electrostatic charge image developing toner, based on an extremely narrow particle size distribution and good electrical characteristics, the image is stable, has excellent reproducibility of fine lines, and has excellent image characteristics such as no fogging. It is suitable as a toner material for image development.

Hereinafter, the present invention will be described in detail.
[Dispersion stabilizer]
The dispersion stabilizer for suspension polymerization of the present invention is characterized in that hydrophobic spherical silica particles are dispersed in an aqueous medium in the presence of a hydrophilic organic compound.

<Hydrophobic spherical silica particles>
The characteristics of the hydrophobic spherical silica particles used as a dispersion stabilizer for suspension polymerization when producing organic resin particles will be described in detail.
The hydrophobic spherical silica particles used in the present invention are
(A1) obtaining hydrophilic spherical silica particles substantially consisting of SiO ₂ units by hydrolyzing and condensing a tetrafunctional silane compound, a partially hydrolyzed condensation product thereof, or a combination thereof;
(A2) R ¹ SiO _3/2 units (wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms) are introduced onto the surface of the hydrophilic spherical silica particles. Process,
(A3) Further, R ² ₃ SiO _1/2 units (wherein each R ² is the same or different and is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms) on the surface of the hydrophilic spherical silica particles. And the step of introducing
Hydrophobic spherical silica particles (1) having a particle size in the range of 0.005 to 1.0 μm, a particle size distribution D90 / D10 of 3 or less, and an average circularity of 0.8 to 1.

Particle size The hydrophobic spherical silica particles have a particle size of 0.005 to 1.00 μm (5 to 1000 nm), preferably 0.01 to 0.30 μm (10 to 300 nm), particularly preferably 0.01 to 0.20 μm (10 to 200 nm). Here, the particle diameter is measured by a dynamic light scattering method / laser Doppler method nanotrack particle size distribution measuring apparatus (for example, Nikkiso Co., Ltd., trade name: UPA-EX150), and the volume-based median diameter is defined as the particle diameter. did. The median diameter is a particle diameter corresponding to 50% cumulative when the particle size distribution is expressed as a cumulative distribution. When the particle diameter is smaller than 0.005 μm, the effect of improving the dispersion stability of the polymerizable monomer composition droplets in the aqueous medium is reduced, which is not preferable. On the other hand, if it is larger than 1.00 μm, the effect of improving the dispersion stability of the polymerizable monomer composition droplets in the aqueous medium becomes too large.

-Particle size distribution The value of D90 / D10 which is an index of the particle size distribution of the hydrophobic spherical silica particles of the present invention is 3 or less. Here, D10 and D90 are values obtained by measuring the particle diameter, respectively. The particle size distribution of the particles is measured by a dynamic light scattering method / laser Doppler method nanotrack particle size distribution measuring device (for example, Nikkiso Co., Ltd., trade name: UPA-EX150), and the volume-based median diameter is used as the particle size. The particle diameter that is 10% cumulative from the smaller side is referred to as D10, and the particle diameter that is 90% cumulative from the smaller side is referred to as D90. As described above, the median diameter is a particle diameter corresponding to a cumulative 50% when the particle size distribution is expressed as a cumulative distribution. The hydrophobic spherical silica particles of the present invention are characterized in that D90 / D10 is 3 or less, and since the particle size distribution is sharp, the particle size distribution of the produced organic resin particles can be sharpened. preferable. The D90 / D10 is more preferably 2.9 or less.

-Average circularity The average circularity of the hydrophobic spherical silica particles of the present invention is preferably from 0.8 to 1, more preferably from 0.92 to 1. Here, “spherical” includes not only a true sphere but also a slightly distorted sphere. Such a “spherical” shape refers to a particle having an average circularity in the range of 0.8 to 1 when evaluated by circularity when particles are projected two-dimensionally. In the present application, the degree of circularity is (peripheral length of a circle equal to the particle area) / (particle peripheral length). This circularity can be measured by image analysis of a particle image obtained with an electron microscope or the like. The average circularity can be obtained by observing with an electron microscope, measuring 100 primary particles, and averaging them.

-Hydrophobicity Scale The hydrophobic scale of the hydrophobic spherical silica particles of the present invention is not particularly limited, but for example, the degree of hydrophobicity (methanol wettability) can be suitably used. A degree of hydrophobicity measured by the following procedure is preferably 60% or more, particularly 65% or more. If this value is less than 60%, the resulting organic resin particles may not be provided with good environmental resistance, or when the organic resin particles are applied as an electrostatic charge developing toner, the charging stability may deteriorate. is there.

Here, the said degree of hydrophobicity as used in the field of this invention means the numerical value obtained by the following procedures.
1) Weigh 0.2 g of sample into a 200 ml beaker and add 50 ml of pure water.
2) Add methanol below the liquid level while stirring magnetically.
3) The point at which the sample is no longer recognized on the liquid level is the end point.
4) The degree of hydrophobicity is calculated from the amount of methanol required by the following formula.

In the step (A1), the term “substantially composed of SiO ₂ units” means that the hydrophilic spherical silica particles are basically composed of SiO ₂ units, but are composed only of the units. It does not mean that at least the surface may have a large number of silanol groups as is generally known. In some cases, some of the hydrolyzable groups (hydrocarbyloxy groups) derived from the raw material tetrafunctional silane compound and / or its partial hydrolysis-condensation product are not converted into silanol groups but in a slight amount. It means that it may remain on the surface or inside.

  As described above, in the present invention, the small particle size sol-gel silica obtained by hydrolysis of a tetrafunctional silane compound such as tetraalkoxysilane in the step (A1) is used as a silica base (silica before hydrophobization treatment). In addition, when it is obtained as a powder by performing a specific surface treatment, the particle size after the hydrophobization treatment maintains the primary particle size of the silica raw material, is not agglomerated, and has a small particle size Thus, good hydrophobic silica particles can be obtained as a dispersion stabilizer for suspension polymerization.

  Use of tetraalkoxysilane having a small number of carbon atoms in the alkoxy group as a silica particle having a small particle diameter, use of an alcohol having a small number of carbon atoms as a solvent, increasing the hydrolysis temperature, during hydrolysis of tetraalkoxysilane By changing the reaction conditions such as lowering the concentration of the catalyst and lowering the concentration of the hydrolysis catalyst, a silica raw material having an arbitrary small particle diameter can be obtained.

  By subjecting this small particle size silica stock to a specific surface treatment, as described above and as described in more detail below, the desired hydrophobic silica particles are obtained.

  Next, one method for producing the hydrophobic spherical silica particles will be described in detail below.

<Method for producing hydrophobic spherical silica particles (1)>
The hydrophobic spherical silica particles of the present invention are
Step (A1): Step of synthesizing hydrophilic spherical silica particles from a tetrafunctional silane compound or the like,
Step (A2): surface treatment step with a trifunctional silane compound,
Step (A3): Obtained by a surface treatment step with a functional silane compound. Hereinafter, each process is demonstrated one by one.

Step (A1): Synthesis step of hydrophilic spherical silica particles General formula (I):
Si (OR ³ ) ₄ (I)
(Wherein each R ³ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms), a tetrafunctional silane compound, a partial hydrolysis product thereof, or a mixture thereof, Hydrolysis and condensation in a mixed solution of a hydrophilic organic solvent containing a hydrophilic substance and water provides a mixed solvent dispersion of hydrophilic spherical silica particles.

In the above general formula (I), R ³ is a monovalent hydrocarbon group having 1 to 6 carbon atoms, preferably a monovalent hydrocarbon group having 1 to 4 carbon atoms, particularly preferably 1 to 2 carbon atoms. is there. Examples of the monovalent hydrocarbon group represented by R ³ include an alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group; and an aryl group such as a phenyl group, preferably a methyl group, An ethyl group, a propyl group, or a butyl group, particularly preferably a methyl group or an ethyl group.

  Examples of the tetrafunctional silane compound represented by the general formula (I) include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane; and tetraphenoxysilane, preferably , Tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane and tetrabutoxysilane, particularly preferably tetramethoxysilane and tetraethoxysilane. Examples of the partial hydrolysis-condensation product of the tetrafunctional silane compound represented by the general formula (I) include alkyl silicates such as methyl silicate and ethyl silicate.

The hydrophilic organic solvent is not particularly limited as long as it dissolves the tetrafunctional silane compound represented by the general formula (I), the partial hydrolysis-condensation product, and water. For example, alcohols ; Cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, cellosolve acetate; ketones such as acetone and methyl ethyl ketone; ethers such as dioxane and tetrahydrofuran, etc., preferably alcohols and cellosolves, particularly preferably Examples include alcohols. Examples of the alcohols include general formula (V):
R ⁵ OH (V)
[Wherein, R ⁵ is a monovalent hydrocarbon group having 1 to 6 carbon atoms].

In the general formula (V), R ⁵ is a monovalent hydrocarbon group having 1 to 6 carbon atoms, preferably a monovalent hydrocarbon group having 1 to 4 carbon atoms, particularly preferably 1 to 2 carbon atoms. is there. Examples of the monovalent hydrocarbon group represented by R ⁵ include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group, preferably a methyl group, an ethyl group, a propyl group, and an isopropyl group. Preferably a methyl group and an ethyl group are mentioned. Examples of the alcohol represented by the general formula (V) include methanol, ethanol, propanol, isopropanol, butanol and the like, preferably methanol and ethanol. As the number of carbon atoms in the alcohol increases, the particle diameter of the produced spherical silica particles increases. Therefore, methanol is preferred in order to obtain the desired small particle size silica particles.

Examples of the basic substance include ammonia, dimethylamine, diethylamine and the like, preferably ammonia, diethylamine, and particularly preferably ammonia. These basic substances may be dissolved in water in a required amount, and the obtained aqueous solution (basic) may be mixed with the hydrophilic organic solvent.
The basic substance is used in an amount of 0.01 to 2 mol with respect to a total of 1 mol of the hydrocarbyloxy group of the tetrafunctional silane compound represented by the general formula (I) and / or its partial hydrolysis-condensation product. It is preferable that it is 0.02-0.5 mol, and it is especially preferable that it is 0.04-0.12 mol. At this time, the smaller the amount of the basic substance, the more desirable small particle size silica particles.

  The amount of water used in the hydrolysis and condensation is 0.000 per 1 mol in total of the hydrocarbyloxy groups of the tetrafunctional silane compound represented by the general formula (I) and / or the partial hydrolysis condensation product thereof. It is preferably 5 to 5 mol, more preferably 0.6 to 2 mol, and particularly preferably 0.7 to 1 mol. The ratio of the hydrophilic organic solvent to water (hydrophilic organic solvent: water) is preferably 0.5 to 10 in terms of mass ratio, more preferably 3 to 9, and more preferably 5 to 8. Particularly preferred. As the amount of the hydrophilic organic solvent is increased, silica particles having a desired small particle diameter can be obtained.

  Hydrolysis and condensation of the tetrafunctional silane compound represented by the general formula (I) can be carried out by a well-known method, that is, in a mixture of a hydrophilic organic solvent containing a basic substance and water in the general formula (I). It is performed by adding a tetrafunctional silane compound or the like shown.

  Generally the density | concentration of the silica particle in the mixed solvent dispersion liquid of the hydrophilic spherical silica particle obtained by this process (A1) is 3-15 mass%, Preferably it is 5-10 mass%.

Step (A2): Surface treatment step with a trifunctional silane compound In the mixed solvent dispersion of the hydrophilic spherical silica particles obtained in the step (A1), the general formula (II):
R ¹ Si (OR ⁴ ) ₃ (II)
Wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and each R ⁴ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms. By adding a trifunctional silane compound, or a partial hydrolysis product thereof, or a mixture thereof, and treating the surface of the hydrophilic spherical silica particles thereby, the surface of the hydrophilic spherical silica particles is R. ¹ SiO _3/2 unit (R ¹ is as described above) is introduced to obtain a mixed solvent dispersion of the first hydrophobic spherical silica particles.

  Step (A2) is indispensable for suppressing aggregation of silica particles in the subsequent concentration step. If the aggregation cannot be suppressed, the individual particles of the resulting silica-based powder cannot maintain the primary particle size, so that the effect as a dispersion stabilizer is deteriorated.

In the general formula (II), R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 3 carbon atoms, particularly preferably 1 to 2 carbon atoms. Is a valent hydrocarbon group. Examples of the monovalent hydrocarbon group represented by R ¹ include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, butyl group and hexyl group, preferably methyl group, ethyl group, n -A propyl group or an isopropyl group, particularly preferably a methyl group or an ethyl group. Further, some or all of the hydrogen atoms of these monovalent hydrocarbon groups may be substituted with halogen atoms such as fluorine atom, chlorine atom, bromine atom, preferably fluorine atom.

In the general formula (II), R ⁴ is a monovalent hydrocarbon group having 1 to 6 carbon atoms, preferably a monovalent hydrocarbon group having 1 to 3 carbon atoms, particularly preferably 1 to 2 carbon atoms. is there. Examples of the monovalent hydrocarbon group represented by R ⁴ include alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group, preferably a methyl group, an ethyl group, or a propyl group, and particularly preferably a methyl group. Or an ethyl group is mentioned.

  Examples of the trifunctional silane compound represented by the general formula (II) include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, and n-propyltriethoxy. Unsubstituted or halogen-substituted trisilane such as silane, isopropyltrimethoxysilane, isopropyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, trifluoropropyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane Alkoxysilane, etc., preferably methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane and ethyltriethoxysilane, more preferably methyltrimethoxysilane Emissions and methyltriethoxysilane, or they partially hydrolyzed condensation products thereof.

  The addition amount of the trifunctional silane compound represented by the general formula (II) is 0.001 to 1 mol, preferably 0.01 to 0.1 mol, per mol of Si atom of the hydrophilic spherical silica particles used. Most preferably, it is 0.01-0.05 mol. When the addition amount is less than 0.001 mol, the dispersibility of the obtained hydrophobic spherical silica particles is deteriorated, so that the dispersion stabilizing effect may be deteriorated. When the addition amount is more than 1 mol, the silica particles may be aggregated.

  The concentration of the silica particles in the mixed solvent dispersion of the first hydrophobic spherical silica particles obtained in the step (A2) is usually 3% by mass or more and less than 15% by mass, preferably 5 to 10% by mass. If the concentration is too low, the productivity may decrease, and if it is too high, the silica particles may aggregate.

-Concentration step The first hydrophobic spherical silica is obtained by removing a portion of the hydrophilic organic solvent and water from the mixed solvent dispersion of the first hydrophobic spherical silica particles thus obtained and concentrating. A mixed solvent concentrated dispersion of particles is obtained. At this time, the hydrophobic organic solvent may be added in advance (before the concentration step) or during the concentration step. In this case, the hydrophobic solvent used is preferably a hydrocarbon or ketone solvent. Specific examples of the solvent include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone and the like, and methyl isobutyl ketone is preferable. Examples of the method for removing a part of the hydrophilic organic solvent and water include distillation and distillation under reduced pressure. The concentrated dispersion obtained has a silica particle concentration of preferably 15 to 40% by mass, more preferably 20 to 35% by mass, and particularly preferably 25 to 30% by mass. If the amount is less than 15% by mass, the surface treatment in the subsequent process may not proceed smoothly. If the amount is more than 40% by mass, the silica particles may be aggregated.

  In the concentration step, the silazane compound represented by the general formula (III) and the monofunctional silane compound represented by the general formula (IV) used as a surface treatment agent in the next step (A3) react with alcohol or water. In addition, the surface treatment becomes insufficient, and when it is subsequently dried, aggregation occurs, and the resulting silica powder cannot maintain the primary particle size, and also has the significance of suppressing the disadvantage that the dispersion stabilizing effect is deteriorated. is there.

Step (A3): Surface treatment step with a functional silane compound: In the mixed solvent dispersion of the first hydrophobic spherical silica particles obtained in the step (A2) and optionally subjected to the concentration step, the mixture of the general formula (III ):
R ² ₃ SiNHSiR ² ₃ (III)
(In the formula, each R ² is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms)
Or a silazane compound represented by formula (IV):
R ² ₃ SiX (IV)
(Wherein R ² is as defined in formula (III), X is an OH group or a hydrolyzable group), and a monofunctional silane compound or a mixture thereof is added, whereby By treating the surface of the first hydrophobic spherical silica particles and introducing R ² ₃ SiO _1/2 units (where R ² is as defined in the general formula (III)) to the surface of the particles, Two hydrophobic spherical silica particles are obtained. By the treatment in this step, R ² ₃ SiO _1/2 units are introduced onto the surface in such a manner that silanol groups remaining on the surface of the first hydrophobic spherical silica particles are triorganosilylated.

In the above general formulas (III) and (IV), R ² is preferably a monovalent hydrocarbon group having 1 to 4 carbon atoms, particularly preferably 1 to 2 carbon atoms. The monovalent hydrocarbon group represented by R ² is, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group or a butyl group, preferably a methyl group, an ethyl group or a propyl group, particularly preferably , Methyl group or ethyl group. Further, some or all of the hydrogen atoms of these monovalent hydrocarbon groups may be substituted with a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom, preferably a fluorine atom.

  Examples of the hydrolyzable group represented by X include a chlorine atom, an alkoxy group, an amino group, and an acyloxy group, preferably an alkoxy group or an amino group, and particularly preferably an alkoxy group.

  Examples of the silazane compound represented by the general formula (III) include hexamethyldisilazane and hexaethyldisilazane, preferably hexamethyldisilazane. Examples of the monofunctional silane compound represented by the general formula (IV) include monosilanol compounds such as trimethylsilanol and triethylsilanol; monochlorosilanes such as trimethylchlorosilane and triethylchlorosilane; monoalkoxy such as trimethylmethoxysilane and trimethylethoxysilane. Silane; monoaminosilane such as trimethylsilyldimethylamine and trimethylsilyldiethylamine; monoacyloxysilane such as trimethylacetoxysilane, preferably trimethylsilanol, trimethylmethoxysilane or trimethylsilyldiethylamine, particularly preferably trimethylsilanol or trimethylmethoxysilane It is done.

  The amount of the silazane compound or / and functional silane compound used is 0.1 to 0.5 mol, preferably 0.2 to 0.4 mol, based on 1 mol of Si atoms in the used hydrophilic spherical silica particles. Most preferably, it is 0.25-0.35 mol. If the amount used is less than 0.1 mol, the dispersibility of the resulting hydrophobic silica particles will be poor, so the effect as a dispersion stabilizer will not appear. When the amount used is more than 0.5 mol, it is economically disadvantageous.

  The hydrophobic spherical silica particles can be obtained as a powder by an ordinary method such as atmospheric drying or reduced pressure drying.

<Hydrophilic organic compound>
In the present invention, the hydrophobic spherical silica particles are dispersed in the aqueous medium in the presence of the hydrophilic organic compound because it is difficult to uniformly disperse the hydrophobic spherical silica particles in the aqueous medium. As a uniform dispersion, hydrophobic spherical silica particles are effectively acted as a dispersion stabilizer in suspension polymerization.

  The hydrophilic organic compound is not particularly limited as long as it can uniformly disperse hydrophobic spherical silica particles in an aqueous medium, and various types of organic compounds can be used. Desirably, the organic resin obtained after suspension polymerization What can be removed more easily than particles is preferred. Specifically, for example, alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, ethers and acetals such as tetrahydrofuran, ketones and aldehydes such as acetone and diacetone alcohol, methyl lactate and the like Esters, polyhydric alcohol derivatives such as glycerin and ethylene glycol, carboxylic acids and anhydrides such as propionic acid, nitrogen-containing compounds such as N, N-dimethylformamide, dimethyl sulfoxide and the like Preferred examples include such sulfur-containing compounds, and fluorine compounds such as 2,2,3,3-tetrafluoropropanol. Particularly preferably, when the polymerizable monomer is suspended in an aqueous medium in which the hydrophobic spherical silica particles are excellent in uniform dispersion of the hydrophobic spherical silica particles and the hydrophobic spherical silica particles are uniformly dispersed. Organic resin obtained after suspension polymerization that is easy to control into droplets with a diameter (polymerizable monomer composition particles) and can be stably polymerized with little influence on the polymerizable monomer composition during suspension polymerization Alcohols, particularly methyl alcohol, ethyl alcohol, and isopropyl alcohol are preferred because they have little influence on the physical properties of the particles and can be easily removed.

The blending amount of the hydrophobic spherical silica particles and the hydrophilic organic compound in the dispersion stabilizer for suspension polymerization according to the present invention is not particularly limited, but in the usage form in the final suspension polymerization system, The blending amount of the hydrophobic spherical silica particles is 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer composition. When the blending amount of the hydrophobic spherical silica particles is less than 0.1 parts by mass with respect to 100 parts by mass of the polymerizable monomer composition, the dispersion stability of the droplets of the polymerizable monomer composition in the polymerization process is reduced. On the other hand, if it exceeds 20 parts by mass, the effect cannot be improved even if it exceeds 20 parts by mass, and it is not economical, and hydrophobic spherical silica particles fixed to the obtained organic resin particles increase, There exists a possibility of reducing the characteristic of an organic resin particle.
Moreover, the compounding quantity of a hydrophilic organic compound is 1-3000 mass parts with respect to 100 mass parts of hydrophobic spherical silica particles, More preferably, 10-1000 mass parts is suitable. When the blending amount of the hydrophilic organic compound is less than 1 part by mass with respect to 100 parts by mass of the hydrophobic spherical silica particles, the hydrophobic spherical silica particles cannot be uniformly dispersed in the suspension polymerization system, resulting in polymerization in the polymerization process. There is a possibility that the dispersion stability of the droplets of the functional monomer composition may not be sufficient. On the other hand, even if the blending amount exceeds 3000 parts by mass, not only is it not possible to improve the uniform dispersion of the hydrophobic spherical silica particles, it is not economical, but the formation of droplets of the polymerizable monomer composition is insufficient. Or the polymerization stability may be insufficient.

<Aqueous medium>
As an aqueous medium used for the dispersion stabilizer of the present invention, water or a water / alcohol mixture can be used. Examples of the alcohol include methyl alcohol, ethyl alcohol, and isopropyl alcohol. As the aqueous medium, water is preferred.

  In the method for producing organic resin particles according to the present invention, hydrophobic spherical silica particles are dispersed in an aqueous medium in the presence of a hydrophilic organic compound to form a uniform dispersion, and then the uniform dispersion (that is, the present invention). It is necessary to suspend the polymerizable monomer composition in the dispersion stabilizer) of the invention or, if necessary, in the dispersion obtained by further adding an aqueous medium.

  An emulsifying and dispersing apparatus for dispersing hydrophobic spherical silica particles in an aqueous medium in the presence of a hydrophilic organic compound to form a uniform dispersion is not particularly limited. K. High pressure shear turbine-type dispersers such as homomixers (manufactured by Tokushu Kika Kogyo Co., Ltd.), high pressures such as piston-type high-pressure homogenizers (from Gorin), microfluidizers (from Microfluidics), etc. Ultrasonic emulsifiers and dispersers such as jet homogenizers and ultrasonic homogenizers (manufactured by Nippon Seiki Seisakusho Co., Ltd.), medium agitating dispersers such as attritors (manufactured by Mitsui Mining Co., Ltd.), colloid mills (( It is desirable to carry out uniform dispersion treatment by using an emulsifying dispersion device such as a forced gap passage type disperser such as Nippon Seiki Seisakusho.

[Polymerizable monomer composition]
The polymerizable monomer composition contains a polymerizable monomer and, optionally, at least one selected from a (co) polymer, a colorant, and other additives.

<Polymerizable monomer>
In the method for producing organic resin particles of the present invention, the polymerizable monomer used is not particularly limited as long as it is capable of suspension polymerization. For example, styrene, o-methylstyrene, m-methyl Styrene monomers such as styrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, acrylic Methyl acid, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, methacryl Isobutyl acid, n-octyl methacrylate, Acrylic acid or methacrylic acid monomers such as dodecyl crylate, 2-ethylhexyl methacrylate, stearyl methacrylate, and other vinyl polymerizable monomers such as ethylene, propylene, butylene, vinyl chloride, vinyl acetate, and acrylonitrile. It can be used alone or in combination of two or more. Of these, styrene monomers, acrylic acid or methacrylic monomers, or combinations thereof are particularly desirable.

  Furthermore, when trying to obtain organic resin particles having a cross-linked structure between molecules, for example, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, decaethylene dimethacrylate Glycol, dimethacrylic acid pentadecaethylene glycol, dimethacrylic acid pentacontactor ethylene glycol, 1,3-butylene dimethacrylate, allyl methacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, phthalic dimethacrylate Aromatic divinylation of (meth) acrylic monomers, divinylbenzene, divinylnaphthalene, and their derivatives having multiple polymerizable double bond groups in the molecule such as diethylene glycol , N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfonic acid and other cross-linking agents, polybudadiene, polyisoprene unsaturated polyester, and JP-B-57-56507, JP-A-59-221304 It is also possible to use reactive polymers described in JP-A-59-221305, JP-A-59-221306, JP-A-59-221307, and the like.

<(Co) polymer>
The polymerizable monomer composition further comprises a (co) polymer or other (co) polymer having the same composition as that of the polymerizable monomer composition, such as a styrene resin, styrene acrylate. By adding a resin, a rosin derivative, an aromatic petroleum resin, a pinene resin, an epoxy resin, a coumarone resin, etc., the particle size distribution can be made uniform. Although it does not specifically limit as this (co) polymer, For example, the weight average molecular weight is about 500-100000, More preferably, the thing of about 1000-50000 is suitable. The amount of such (co) polymer added is suitably about 0 to 50 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

<Colorants and other additives>
Further, in the polymerizable monomer composition, a colorant such as a pigment or a dye, or other additives as necessary, such as magnetic powder, an offset preventing agent, a charge control agent, a plasticizer, a polymerization stabilizer, a charging agent. An inhibitor, a flame retardant, etc. can also be mix | blended or added.

-Pigment Examples of the pigment include inorganic pigments such as lead white, red lead, yellow lead, carbon black, ultramarine, zinc oxide, cobalt oxide, titanium dioxide, iron oxide, silica, titanium yellow, and titanium black; , Naphthol Yellow S, Hanser Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, etc .; Molybdenum Orange, Permanent Orange RK, Benzidine Orange G, Indanthren Brilliant Orange Orange pigments such as GK; Permanent Red 4R, Resol Red, Pyrazolone, Red 4R, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eomin Lake, Rhodamine Lake B, Azaline Red pigments such as violet and brilliant carmine B; purple pigments such as fast violet B, methyl violet lake and dioxane violet; alkali blue lake, victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partial chloride, fast sky Blue pigments such as blue and indanth blue BC; green pigments such as pigment green B, malachite green lake, and fanal yellow green G: other, isoindolinone, quinacridone, perinone pigment, perylene pigment, insoluble azo pigment, soluble azo Organic pigments such as pigments and dye lakes are used.

・ Dye As the above dye, for example, nitroso dye, nitro dye, azo dye, stilbene azo dye, diphenylmethane dye, triphenylmethane dye, xanthene dye, acridine dye, quinoline dye, methine dye, polymethine dye, thiazole dye, indamine dye Indophenol dyes, azine dyes, oxazine dyes, thiazine dyes, sulfur dyes and the like are used.

Magnetic powder Examples of the magnetic powder include powders of ferromagnetic metals such as iron, cobalt, and nickel; powders of metal compounds such as magnetite, hematite, and ferrite. These magnetic powders also act as colorants.

  These colorants and other additives may be surface-treated by various methods for the purpose of improving dispersibility in the polymerizable monomer. Surface treatment methods include treatment with long-chain hydrocarbons such as stearic acid and oleic acid, treatment with polymerizable monomers having polar groups such as acrylic acid and methacrylic acid, and various methods such as trimethylolpropane. A method of treating with a monohydric alcohol, a method of treating with an amine such as triethanolamine, a method of treating with various coupling agents, or an aziridine group capable of reacting with a functional group on the surface of a colorant or other additive, oxazoline A polymer having a reactive group such as a group, an N-hydroxyalkylamide group, an epoxy group, a thioepoxy group, an isocyanate group, a vinyl group, a silicon hydrolyzable group or an amino group at a temperature of 20 to 350 ° C. Or the method of grafting this polymer on the surface of another additive can be mentioned. In particular, for example, when carbon black is used as a colorant, it is preferable to use carbon black graft polymers described in JP-A-63-270767 and JP-A-63-265913 as the polymer. Specifically, the following two methods are preferable.

  (A) a method of surface-treating carbon black with a polymer (P) having a reactive group (X) capable of reacting with a functional group of carbon black, and (b) a double bond group in the presence of carbon black. A method of surface-treating carbon black by polymerizing one vinyl monomer (A).

  First, the method (A) will be described.

  The reactive group (X) capable of reacting with the functional group of carbon black is not particularly limited as long as it can react with the functional group of carbon black, but is not limited to an epoxy group, a thioepoxy group, an aziridine group, and an oxazoline group. Examples include heterocyclic groups such as isocyanate groups, N-hydroxyalkylamide groups and amino groups. Among these, a heterocyclic group is preferable, and an epoxy group, an aziridine group, and an oxazoline group are particularly preferable in consideration of reactivity with the functional group of carbon black. Although the number of reactive groups (X) depends on the relationship with the number of functional groups of carbon black, it is desirable that the average number per molecule of the polymer is 50 to 1, preferably about 20 to 1.

  The polymer (P) having a reactive group (X) is not particularly limited as long as it has a reactive group (X) that can react with the functional group of carbon black. Examples of the polymer (P) include a polysiloxane structure, a poly (meth) acrylic structure, a polyether structure, a polyester structure, a polyalkylene structure, a polyamide structure, a polyimide structure, a polyurethane structure, and a polystyrene structure. Examples thereof include a structure or a copolymer thereof, and may be a linear or branched structure.

  In particular, as the polymer (P), a vinyl polymer, a vinyl polymer and a block or a block can be used because the dispersibility in the vinyl monomer (B) having two or more double bond groups can be increased. A copolymer forming a graft type polymer is preferred. The vinyl polymer is not particularly limited, but is preferably a vinyl monomer having a reactive group (X) capable of reacting with a functional group of carbon black alone or another vinyl monomer copolymerizable with the monomer ( For example, vinyl polymers (poly (meth) acrylic, polystyrene) obtained by (co) polymerizing (meth) acrylic acid, (meth) acrylic acid esters, (meth) acrylamide, styrene, etc.) ).

  Further, if the polymer (P) has a reactive group (Y) capable of reacting with a vinyl monomer (B) having two or more double bond groups, a vinyl monomer (B ) And the reactive group (Y) as a result of the reaction, the carbon black is fixed in the resulting particles, so that the strength and hardness of the particles can be easily gap-controlled, and the bleeding of the pigment and impurities derived therefrom is This is preferable because a highly reliable colored spacer can be obtained.

The molecular weight of the polymer (P) is not particularly limited, but is preferably Mn = 200 to 1 × 10 ⁶ , more preferably from the viewpoint of the remarkable treatment effect on carbon black and the workability of carbon black. It is 300-1 * 10 < ⁵ >, More preferably, it is 1000-5 * 10 < ⁴ >.

  The reactive group (Y) capable of reacting with the vinyl monomer (B) having two or more double bond groups is not particularly limited, but includes a double bond group, a hydroxyl group, an amino group, a carboxyl group, and an alkoxysilyl group. It is preferable that it is at least 1 type or 2 types or more selected from the group which consists of, and a double bond group is especially preferable from a reactive point with a vinyl-type monomer (B). The number of reactive groups (Y) is not particularly limited, but is preferably 20 to 1 on average per polymer molecule, and more preferably about 10 to 1.

  The polymer (P) having these reactive groups (X) is prepared from a corresponding monomer by a conventionally known method such as bulk polymerization method, suspension polymerization method, emulsion polymerization method, precipitation polymerization method, solution polymerization method, etc. Can be obtained by polymerization. Moreover, after forming a polymer beforehand, you may introduce | transduce a reactive group into this polymer.

  The treatment of the carbon black and the polymer (P) having a reactive group (X) capable of reacting with the functional group of the carbon black can be performed by various methods. For example, the carbon black and the polymer (P ) With stirring under a temperature condition of from room temperature to 350 ° C. According to this method, when the carbon black in the secondary agglomerated state used as a raw material is stirred and mixed, the carbon black is efficiently crushed to have a fine and uniform particle diameter, and the reaction efficiency is improved.

  If necessary, the above reaction can also be carried out in the presence of a dispersion medium. As the dispersion medium to be used, a nonpolar solvent having a boiling point of 150 ° C. or lower is preferable because it does not react with the reactive group (X).

  The reaction between carbon black and polymer (P) in the presence of such a dispersion medium is, for example, 50 to 150 ° C., preferably 70 to 140 ° C., for 0.5 to 10 hours, preferably 1 to It is carried out by stirring and mixing for 5 hours.

  The ratio of the carbon black and the polymer (P) is not particularly limited, but the polymer (P) is 1 to 5000 parts by weight, preferably 1 to 1000 parts by weight, more preferably 2 to 100 parts by weight of the carbon black. It is desirable to set it to -250 mass parts. That is, if the proportion of the polymer (P) is less than 1 part by mass, it may be difficult to sufficiently modify the properties of carbon black, particularly the surface properties, while the proportion of the polymer (P). When the amount exceeds 5000 parts by mass, the proportion of the polymer (P) bonded to the carbon black increases, which is not economical and may impair the required characteristics of the carbon black.

  Next, the method (b) will be described.

  Although it does not specifically limit as a vinyl-type monomer (A) which has one double bond group, Preferably (meth) acrylic acid, (meth) acrylic acid esters, (meth) acrylamides, styrenes, vinyl Examples include esters. When these vinyl monomers (A) are polymerized, radicals at the growing end during polymerization are trapped in the benzene ring of carbon black, and the polymer of vinyl monomers (A) is grafted on the surface of carbon black. Is done. Even if the vinyl monomer (A) does not have the reactive group (X) as described above, the carbon black surface is treated with the polymer of the vinyl monomer (A) by the mechanism described above.

  Examples of the method for polymerizing the vinyl monomer (A) in the presence of carbon black include conventionally known polymerization methods such as a bulk polymerization method and a solution polymerization method. From the viewpoint that the polymer is efficiently grafted on the carbon black surface, the bulk polymerization method and the solution polymerization method are preferable, and the bulk polymerization method is most preferable. In the suspension polymerization method and the emulsion polymerization method using water, carbon black is present in water, so that the grafting efficiency is deteriorated. For example, the polymerization is performed by stirring and mixing carbon black and vinyl monomer (A) as they are or in the presence of a solvent, together with a polymerization initiator, at room temperature to 350 ° C., preferably 50 to 200 ° C. Is done.

  By this method, when the carbon black in the secondary agglomerated state used as a raw material is stirred and mixed and reacted, it is efficiently crushed and becomes a fine and uniform particle size.

  The ratio of carbon black and vinyl monomer (A) is not particularly limited, but vinyl monomer (A) is 1 to 5000, preferably 10 to 5000, more preferably 100 parts by mass of carbon black. Is preferably 20 to 5000 parts by mass. If the proportion of the vinyl monomer (A) is less than 1 part by mass, it may be difficult to sufficiently modify the properties of carbon black, particularly the surface properties, while if it exceeds 5000 parts by mass. Further, it becomes impossible to suppress the heat generation of the polymerization, and the ratio of the polymer bonded to the carbon black increases, which is not economical and may impair the required characteristics of the carbon black.

  The carbon black surface-treated with the polymer (P) obtained by the above methods (a) and (b) may be used as it is, but a method of removing a polymer that has not reacted with the carbon black surface. Is desirable.

  Further, when a colorant other than carbon black is used, a surface-treated colorant obtained by the method described in JP-A-1-118573 is preferable.

-Low molecular weight polymer Furthermore, the dispersibility to polymerizable monomers, such as carbon black, can be aimed at by adding a low molecular weight polymer in a polymerizable monomer composition. Although it does not specifically limit as a low molecular weight polymer, For example, a styrene resin, a styrene acrylate resin, a rosin derivative, an aromatic petroleum resin of a weight average molecular weight of about 500 to 100,000, more preferably about 1,000 to 50,000. , Pinene resin, epoxy resin, coumarone resin and the like. The addition amount of the low molecular weight polymer depends on the blending amount of carbon black or the like, but about 0 to 50 parts by mass is appropriate for 100 parts by mass of the polymerizable monomer.

-Anti-offset agent When an electrostatic charge image developing toner particle base material is to be produced by the method for producing organic resin particles of the present invention, an anti-offset agent is added in addition to the colorant and / or magnetic powder as described above. It is desirable to add. The offset preventing agent is not particularly limited, but a polymer having a ring and ball softening point of 80 to 180 ° C., for example, a polyolefin having a weight average molecular weight of 1000 to 45000, more preferably about 2000 to 6000, so-called polyolefin wax is used. Can be used. For example, polyolefin waxes include homopolymers such as polyethylene, polypropylene, and polybutylene, ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-pentene copolymers, and ethylene-3-methyl-1-butene copolymers. Olefin copolymers such as copolymers, ethylene-propylene-butene copolymers, or olefins and other monomers, for example, vinyl ethers such as vinyl methyl ether, vinyl-n-butyl ether, vinyl phenyl ether, vinyl acetate, Vinyl esters such as vinyl butyrate, vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, haloolefins such as vinyl chloride, vinylidene chloride, tetrachloroethylene, methyl acrylate, ethyl acrylate, n-butyl acrylate (Meth) acrylates such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, stearyl methacrylate, N, N-dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, acrylonitrile, N, Examples thereof include acrylic acid derivatives such as N-dimethylacrylamide, organic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid, and copolymers with diethyl fumarate, β-pinene, and the like.

  In addition to the above-mentioned polyolefins, as an anti-offset agent, natural or synthetic paraffin waxes, particularly high melting point paraffin waxes having a melting point of 60 to 70 ° C., zinc stearate, barium salt, lead salt, cobalt Salts, calcium and magnesium salts and magnesium salts, zinc salts of olefinic acids, manganese salts, iron salts, lead salts, and fatty acid metal salts such as zinc salts, cobalt salts, magnesium salts of palmitic acid, especially 17 carbon atoms Higher fatty acid salts as above, higher alcohols such as myricyl alcohol, polyhydric alcohol esters such as stearic acid glyceride and palmitic acid glyceride, fatty acid esters such as myricyl stearate and myricyl palmitate, montanic acid moiety Fatty acid partial saponified esters such as saponified esters , Stearic acid, palmitic acid, higher fatty acids such as montanic acid, fatty acid amides such as ethylene bis-stearoyl amide, and mixtures thereof and the like are used.

  Furthermore, it is also possible to use a crystalline (meth) acrylic acid ester polymer as described in JP-A-6-148936, JP-A-6-194874, JP-A-6-194877 and the like as an anti-offset agent. Is possible. Use of a crystalline (meth) acrylic acid ester polymer can be expected to improve various properties such as offset resistance, releasability, fluidity, and charge rise.

  As a crystalline (meth) acrylic acid ester-based polymer used as an offset inhibitor, for example, a monomer represented by the following general formula (VI) is preferably used as a constituent unit, preferably 100 to 50 mol%, more preferably 100 to The thing containing 60 mol%, More preferably, 100-70 mol% is mentioned.

(In the formula, R ⁶ represents hydrogen or a methyl group, and n is an integer of 15 to 32, more preferably an integer of 18 to 32, and still more preferably an integer of 21 to 32.)

  Specific examples of the monomer represented by the general formula (VI) include stearyl acrylate, stearyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate, heptadecyl acrylate, heptadecyl methacrylate, nonadecyl acrylate, and methacrylic acid. Nonadecyl, aralkyl acrylate, aralkyl methacrylate, behenyl acrylate, behenyl methacrylate, pentasil acrylate, pentasil methacrylate, heptacil acrylate, heptacyl methacrylate, nonacyl acrylate, nonacyl methacrylate, doteracyl acrylate, doteracyl methacrylate, etc. Is mentioned. Of these, stearyl acrylate, behenyl acrylate, behenyl methacrylate, pentasil acrylate, pentasil methacrylate and the like are particularly preferable.

  Examples of the monomer copolymerizable with the monomer represented by the general formula (VI) include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, and p-methoxy. Styrene monomers such as styrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene; methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic acid Isobutyl, dodecyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methyl α-chloroacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n methacrylate -Octyl, dodecyl methacrylate, methacryl Amorphous acrylic acid ester or amorphous methacrylic acid ester monomers such as 2-ethylhexyl acid; acrylic acid monomers such as acrylonitrile, methacrylonitrile, acrylamide; vinyl methyl ether, vinyl isobutyl ether, vinyl ethyl ether, etc. Vinyl ether monomers; vinyl ketone monomers such as vinyl methyl ketone, vinyl ethyl ketone and vinyl hexyl ketone; N-vinyl compound monomers such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; Other examples include various vinyl monomers such as ethylene, propylene, butylene, vinyl chloride, and vinyl acetate.

  The weight average molecular weight of such a crystalline (meth) acrylic acid ester polymer is about 35,000 to 500,000, more preferably about 35,000 to 450,000, and still more preferably about 35,000 to 400,000. That is, if the weight average molecular weight is less than 35,000, the melt viscosity is too low to obtain the desired offset prevention effect, and good dispersion of the crystalline (meth) acrylate polymer in the toner particles. On the other hand, if the weight average molecular weight exceeds 500,000, the melt viscosity is too high, the melt characteristics are lowered, and offset resistance can be exhibited. This is because there is a high risk of disappearance.

  In order to obtain a low-temperature fixing toner, it is also desirable to use coumarone resin, epoxy resin, low molecular weight polystyrene or the like in place of or in combination with the above-described offset preventive agent.

-Charge control agent Examples of the charge control agent used when obtaining an electrostatic charge image developing toner include nigrosine, monoazo dyes, zinc, hexadecyl succinate, alkyl esters or alkylamides of naphthoic acid, and nitrohumic acid. N, N-tetramethyldiamine benzophenone, N, N-tetramethylbenzidine, triazine, salicylic acid metal complex, and the like. As will be described later, such a charge control agent is preferably added externally to the resin particles obtained after suspension polymerization, rather than being added during suspension polymerization.

-Polymerization initiator As a polymerization initiator used for the polymerization of the polymerizable monomer, an oil-soluble peroxide-based or azo-based initiator usually used for suspension polymerization can be used. For example, for example, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, orthochloroperoxide benzoyl, orthomethoxybenzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, cyclohexanone peroxide, t -Peroxide initiators such as butyl hydroperoxide, 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-isopropylbuty Nitrile), 1,1′-azobis (cyclohexane-1-carbonitrile) 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2- (carbamoylazo) isobutyronitrile, 4, 4'-azobis (4-cyanovaleric acid), dimethyl-2,2'-azobisisobutyrate and the like. The polymerization initiator is preferably used in an amount of 0.01 to 20% by mass, particularly 0.1 to 10% by mass, based on the polymerizable monomer.

[Method for producing organic resin particles (suspension polymerization)]
<Production method>
The method for producing the organic resin particles according to the present invention includes the polymerizable monomer composition comprising the polymerizable monomer as described above and optionally various other compounds or additives as described above. The dispersion stabilizer is added to an aqueous medium containing the dispersion stabilizer, and stirred to form droplets (polymerizable monomer composition particles) having a desired particle size to perform suspension polymerization. In this suspension polymerization, the reaction is preferably carried out after regulating the particle size of the droplets or while regulating the particle size, but it is particularly preferred to carry out the reaction after regulating the particle size. The regulation of the particle diameter is, for example, that a suspension in which a predetermined component is dispersed in an aqueous medium is T.D. K. Stirring is performed with a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Alternatively, it is carried out by passing it once or several times through a high-speed stirrer such as a line mixer (for example, Ebara Milder manufactured by Ebara Seisakusho). In this way, the droplet diameter is set to a predetermined size, for example, 0.1 to 500 μm, preferably 0.5 to 100 μm, and more preferably about 0.5 to 50 μm.

<Surfactant>
In the method for producing organic resin particles of the present invention, a surfactant may be further added to improve the polymerization stability during suspension polymerization. As the surfactant, any of an anionic surfactant, a cationic surfactant, a zwitterionic surfactant, and a nonionic surfactant can be used.

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, alkyl phosphate ester salt, naphthalene sulfonate formalin condensate, polyoxyethylene alkylphenyl ether sulfate, polyoxyethylene alkyl sulfate, and the like.
Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.
Examples of the zwitterionic surfactant include lauryl dimethylamine oxide.
Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxyethylene- Examples include oxypropylene block polymers.

  These surfactants can be added in an amount of 0 to 5% by mass, preferably 0.1 to 1% by mass, based on the polymerizable monomer composition.

<Emulsion polymerization inhibitor>
In addition, in the method for producing organic resin particles of the present invention, an emulsion polymerization inhibitor can be further added during suspension polymerization in order to prevent emulsion polymerization occurring in the aqueous phase. Examples of emulsion polymerization inhibitors include inorganic water-soluble inhibitors such as ammonium thiocyanate, cupric chloride, copper acetate, vanadium pentoxide, sodium nitrite, potassium nitrite, potassium dichromate, potassium oxalate, and trisodium citrate. Water-soluble mercaptan compounds such as 2-mercaptoethanol, thioglycolic acid, cysteine, glutathione, dimercaprol, 1,4-dithiothreitol, dimercaptosuccinic acid, 2,3-dimercapto-1-propanesulfonic acid, ethylenediamine compounds, Examples include water-soluble nigrosine, borohydride, and metal complex compounds of monoazo dyes. Further, it has at least one structural unit selected from the group consisting of —SH, —S—S—, —COOH, —NO ₂ and —OH, as disclosed in JP-A-8-183807, and substantially contains water. Insoluble and poorly soluble in a polymerizable monomer, or a fragrance having at least one of —NO ₂ , —SO ₃ Na and a secondary amino group as disclosed in JP-A-7-316209 And emulsion polymerization inhibitors comprising a group compound.

<Polymerization temperature>
The polymerization temperature depends on the type of polymerizable monomer used and the like, but it is 10 to 90 ° C, preferably about 30 to 80 ° C.

[Organic resin particles]
The organic resin particles obtained by the method for producing organic resin particles of the present invention as described above are dispersed in suspension droplets by the action of the dispersion stabilizer for suspension polymerization as described above during suspension polymerization. Is maintained favorably, the volume average particle size is 0.1 to 500 μm, particularly 0.5 to 100 μm, more particularly about 0.5 to 50 μm, and the particle size distribution (volume average particle size / number average particle size Ratio) is 1.6 or less.

<Application>
Since the organic resin particles obtained by the production method of the present invention have a very narrow particle size distribution as described above, the obtained organic resin particles have excellent fluidity when taken out as dry particles, and the adhesion and coalescence of the particles are excellent. If the hydrophobic spherical silica particles added during suspension polymerization are fixed on the surface of the organic resin particles and the environmental properties such as moisture resistance are good, and further dispersion in the liquid is necessary Since it has excellent physical properties such as thermal properties, electrical properties, and powder properties, such as extremely excellent redispersibility, it is suitably used in various applications. In addition, since the particle size distribution is extremely narrow, the classification process can be simplified, the yield is high, and the productivity is excellent.

  For example, colored organic resin particles obtained by adding a colorant to a polymerizable monomer in suspension polymerization can be used as a toner for developing an electrostatic image.

<Toner for electrostatic image development>
Since the toner for developing an electrostatic charge image according to the present invention has a narrow particle size distribution, the classification process can be simplified, the yield is high and the productivity is excellent, and the organic product thus obtained is used. Since the hydrophobic spherical silica particles used as one component of the dispersion stabilizer are immobilized on the surface of the resin particles, the resulting organic resin particles have little change in electrical characteristics due to environmental conditions and are negatively charged. Therefore, when used as an electrostatic charge image developing toner, based on an extremely narrow particle size distribution and good electrical characteristics, the image is stable and fine line reproducibility is good. The toner can be suitably used as an electrostatic image developing toner having excellent image quality characteristics such as no fogging.

The electrostatic image developing toner according to the present invention is formed using the colored organic resin particles. In order to obtain an appropriate chargeability of the toner, the volume average particle size is set to 3.5 to 3.5. 20 μm, preferably 4 to 15 μm, and the particle size distribution (ratio of volume average particle size / number average particle size) is 1.6 or less. The colored organic resin particles can be directly used as a toner for developing an electrostatic image.
In addition, additives commonly used in ordinary toners such as charge control agents and fluidizing agents for charge adjustment may be appropriately blended.

  The method for blending the charge control agent is not particularly limited, and any conventionally known method can be adopted. For example, when a polymerizable monomer in which a colorant is dispersed is polymerized, a charge control agent is included in the monomer in advance, or the colored organic resin particles of the present invention are post-treated with a charge control agent. For example, a method of attaching the charge control agent to the surface of the colored organic resin particles can be appropriately employed. Further, by further externally adding a charge control agent to the surface of the organic resin particles, it is possible to easily adjust either positive or negative chargeability having desired charge characteristics.

  In addition, the organic resin particles of the present invention contain the organic resin particles in the resin composition, and prevent light blocking of the film molded product, slipperiness improver, and light diffusing (transparent) resin. Contains thermoplastic and thermosetting resin colorants, coating compositions, decorative board additives, artificial marble additives, and colorants for applications such as colorants and matting agents. In or not including chromatography column fillers, electrostatic charge image developing toner additives, Coulter counter display particles, immunodiagnostic carriers, cosmetic fillers, paper treatment agents, powder coatings, Moreover, it can be suitably used for spacers for liquid crystal display panels and spacers for touch panels.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The following examples do not limit the present invention.

[Synthesis of hydrophobic spherical silica particles]
<Synthesis Example 1>
Step (A1): Step of synthesizing hydrophilic spherical silica particles In a 3 liter glass reactor equipped with a stirrer, a dropping funnel and a thermometer, 989.5 g of methanol, 135.5 g of water, and 28% aqueous ammonia 66 .5 g and mixed. This solution was adjusted to 35 ° C., and 436.5 g (2.87 mol) of tetramethoxysilane was added dropwise over 6 hours while stirring. Even after this dropping was completed, the suspension was further stirred for 0.5 hours to perform hydrolysis, thereby obtaining a suspension of hydrophilic spherical silica particles.

Step (A2): Surface treatment step with trifunctional silane compound 4.4 g (0.03 mol) of methyltrimethoxysilane was added dropwise to the suspension obtained in step (A1) at room temperature over 0.5 hours. Then, stirring was continued for 12 hours after the dropping, and the dispersion of hydrophobic spherical silica particles was obtained by hydrophobizing the surface of the silica particles.

-Concentration step Next, an ester adapter and a condenser tube are attached to a glass reactor, and the dispersion obtained in the previous step is heated to 60 to 70 ° C to distill off 1021 g of a mixture of methanol and water, thereby forming a hydrophobic sphere. A mixed solvent concentrated dispersion of silica particles was obtained. At this time, the content of the hydrophobic spherical silica particles in the concentrated dispersion was 28% by mass.

Step (A3): Surface treatment step with a functional silane compound After adding 138.4 g (0.86 mol) of hexamethyldisilazane to the concentrated dispersion obtained in the previous step at room temperature, this dispersion Was heated to 50-60 ° C. and reacted for 9 hours to trimethylsilylate the silica particles in the dispersion. Subsequently, the solvent in this dispersion was distilled off at 130 ° C. under reduced pressure (6650 Pa) to obtain 186 g of hydrophobic spherical silica particles (1).

  The hydrophilic spherical silica particles obtained in the step (A1) were measured according to the following measuring method 1. Moreover, it measured according to the following measuring methods 2-4 about the hydrophobic spherical silica particle obtained through each step of said process (A1)-(A3). The obtained results are shown in Table 1.

[Measurement methods 1 to 4]
1. Particle size measurement of the hydrophilic spherical silica particles obtained in the step (A1) By adding a silica particle suspension to methanol so that the silica particles are 0.5% by mass, and applying ultrasonic waves for 10 minutes. The particles were dispersed. The particle size distribution of the particles thus treated was measured with a dynamic light scattering method / laser Doppler nanotrack particle size distribution measuring device (trade name: UPA-EX150, manufactured by Nikkiso Co., Ltd.), and the volume-based median diameter was determined. The particle diameter was taken. The median diameter is a particle diameter corresponding to 50% cumulative when the particle size distribution is expressed as a cumulative distribution.

2. Measurement of particle size of hydrophobic spherical silica particles obtained in step (A3) and measurement of particle size distribution D90 / D10 Add the silica particles to methanol so as to be 0.5% by mass, and apply ultrasonic waves for 10 minutes. Then, the particles were dispersed. The particle size distribution of the particles thus treated was measured with a dynamic light scattering method / laser Doppler nanotrack particle size distribution measuring device (trade name: UPA-EX150, manufactured by Nikkiso Co., Ltd.), and the volume-based median diameter was determined. The particle diameter was taken. The particle size distribution D90 / D10 was measured by setting the particle size at 10% cumulative from the small side to D10 and the particle size at 90% cumulative from the small side as D90. D90 / D10 was calculated from the value.

3. Measurement of shape of hydrophobic spherical silica particles The hydrophobic spherical silica particles were observed with an electron microscope (manufactured by Hitachi, Ltd., trade name: S-4700 type, magnification: 100,000 times) to confirm the shape. The term “spherical” includes not only a true sphere but also a slightly distorted sphere. The shape of such particles is evaluated by the circularity when the particles are projected two-dimensionally, and the average circularity is in the range of 0.8-1. Here, the circularity is (peripheral length of a circle equal to the particle area) / (peripheral length of particle). The average circularity was observed with the electron microscope, 100 primary particles were measured, and the average value was used.

4). Measurement of degree of hydrophobicity 0.2 g of a sample is weighed into a 200 ml beaker, 50 ml of pure water is added, and methanol is added below the liquid level while electromagnetically stirring. The end point is the point at which the sample is no longer recognized on the liquid level. The degree of hydrophobicity is calculated from the amount of methanol required by the following formula.

<Synthesis Example 2>
In Synthesis Example 1, except that the amounts of methanol, water, and 28% ammonia water in Step (A1) were changed to 1045.7 g of methanol, 112.6 g of water, and 33.2 g of 28% ammonia water, 188 g of hydrophobic spherical silica particles (2) were obtained. Measurement was performed in the same manner as in Synthesis Example 1 using these hydrophobic spherical silica particles. The results are shown in Table 1.

<Synthesis Example 3>
-Process (A1):
In a 3 liter glass reactor equipped with a stirrer, a dropping funnel and a thermometer, 623.7 g of methanol, 41.4 g of water and 49.8 g of 28% aqueous ammonia were added and mixed. The solution was adjusted to 35 ° C., and 1163.7 g of tetramethoxysilane and 418.1 g of 5.4% aqueous ammonia were simultaneously added to the solution while stirring. The former was added dropwise over 6 hours and the latter over 4 hours. did. Even after the tetramethoxysilane was dropped, the mixture was stirred for 0.5 hours for hydrolysis to obtain a suspension of silica particles.

-Process (A2):
To the suspension thus obtained, 11.6 g of methyltrimethoxysilane (molar ratio of 0.01 equivalent to tetramethoxysilane) was added dropwise at room temperature over 0.5 hours and stirred for 12 hours after the addition. Then, the silica particle surface was treated.

-Concentration step An ester adapter and a condenser tube were attached to the glass reactor, and 1440 g of methyl isobutyl ketone was added to the dispersion containing silica particles subjected to the above surface treatment, followed by heating to 80 to 110 ° C and methanol. Water was distilled off over 7 hours.

-Process (A3):
To the dispersion thus obtained, 357.6 g of hexamethyldisilazane was added at room temperature, heated to 120 ° C., and reacted for 3 hours to trimethylsilylate the silica particles. Thereafter, the solvent was distilled off under reduced pressure to obtain 472 g of hydrophobic spherical silica particles (3).

  The silica particles (3) thus obtained were measured in the same manner as in Synthesis Example 1. The results of silica particles (1) to (3) are shown in Table 1 together with the results of commercially available Aerosil R972 and R974 (manufactured by Nippon Aerosil Co., Ltd.) as comparative examples.

[Synthesis example of treated carbon black]
<Synthesis Example 4>
A flask equipped with a stirrer, an inert gas introduction tube, a reflux condenser, and a thermometer was charged with 400 parts of deionized water in which 0.2 part of polyvinyl alcohol was dissolved. A mixture prepared by dissolving 16 parts of benzoyl peroxide in a previously prepared polymerizable monomer consisting of 194.9 parts of styrene and 5.1 parts of glycidyl methacrylate was mixed and stirred uniformly at high speed. Liquid. Subsequently, the mixture was heated to 80 ° C. while blowing nitrogen gas, and stirred at this temperature for 5 hours to conduct a polymerization reaction, and then cooled to obtain a polymer suspension. This polymer suspension was filtered, washed and dried to obtain a polymer having an average of epoxy groups as reactive groups in one molecule. The molecular weight of this polymer was number average molecular weight Mn = 5,500 according to GPC measurement.

  Laboplast mill (Toyo Seiki Co., Ltd.) 40 parts of polymer having an average of epoxy groups as reactive groups and 20 parts of carbon black MA-100R (Mitsubishi Chemical Co., Ltd.) After being kneaded and reacted under conditions of 160 ° C. and 100 rpm, cooling and pulverization were performed to obtain treated carbon black (1).

[Manufacture of organic resin particles]
<Example 1>
8 g of hydrophobic spherical silica particles (1) are put into an aqueous medium composed of 30 g of ethyl alcohol and 120 g of ion-exchanged water, and a high shear mixing device is used. K. The mixture was stirred for 5 minutes at 4000 rpm with a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to prepare an aqueous dispersion in which hydrophobic spherical silica particles were uniformly dispersed. When the aqueous dispersion of the hydrophobic spherical silica particles was observed with an optical microscope (1000 times), the hydrophobic spherical silica particles were uniformly finely dispersed, and coarse particles of 1 μm or more were not observed.

[Polymerizable monomer composition]
85g of styrene
n-Butyl acrylate 15g
Divinylbenzene 0.3g
Carbon black (1) 10g
Low molecular weight polystyrene 5g
(Mw = 10,000)
Polyethylene wax 3g
(Mn = 2,000)
1,2'-azobisisobutyronitrile 1g
1,2'-azobis (2,4-dimethylvaleronitrile) 1g

  The polymerizable monomer composition is mixed with the pearl mill (manufactured by Ashizawa Co., Ltd.) at 30 ° C. with a residence time in the vessel of 30 minutes, and the pigment is uniformly dispersed. A dispersion was prepared. When this polymerizable monomer composition dispersion was observed with an optical microscope (1000 times), carbon black was uniformly finely dispersed, and coarse particles of 1 μm or more were not observed.

  Next, the aqueous dispersion of hydrophobic spherical silica particles prepared as described above was charged with the polymerizable monomer composition dispersion obtained above and 300 g of ion-exchanged water, and a mixer having a high shearing force at room temperature. Some T. K. A homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) was stirred at 10,000 rpm for 10 minutes to granulate droplets of the polymerizable monomer composition (monomer composition particles).

  The granulated polymerizable monomer composition aqueous dispersion is put into a reactor equipped with a stirring blade, and the whole is uniformly stirred to such an extent that the monomer composition particles do not settle, and the polyoxyethylene alkylsulfuric acid is preliminarily stirred. After charging 30 g of ion-exchanged water in which 0.4 g of phoammonium (Haitenol N-08, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was dissolved, the mixture was heated to 75 ° C. in a nitrogen atmosphere and stirred at this temperature for 6 hours. Subsequently, the suspension polymerization reaction was completed.

  The aqueous dispersion of the polymer composition obtained as described above is cooled to room temperature (40 ° C. or lower), separated into solid and liquid, washed repeatedly with water, and dried to obtain the organic resin particles (1) of the present invention. Obtained.

  When the particle diameter of the obtained organic resin particles (1) was measured using a Coulter counter (manufactured by Nikka Machine Co., Ltd., aperture 100 μm), the volume average particle diameter (dv) was 10.1 μm. The coarse particle size was small, and the particle size distribution, that is, the ratio (dv / dp) of the volume average particle size to the number average particle size (dp) was 1.26, indicating a narrow particle size distribution.

Further, the volume resistivity value of the organic resin particles (1) was measured using a dielectric loss measuring device (TR-1100 type, manufactured by Ando Electric Co., Ltd.) under the conditions of a temperature of 25 ° C. and a frequency of 1 kHz. Its volume resistivity was 5.3 × 10 ¹⁰ Ω · cm.

  Furthermore, when the organic resin particles (1) were observed with an optical microscope (1000 times), each particle showed a completely black sphere, and no ubiquitous carbon black was observed in the particles.

  30 g of the organic resin particles (1) and 720 g of a styrene acrylic resin-coated ferrite carrier were mixed to prepare a two-component developer. An image of this developer was evaluated with a Leo Dry 7610 copier (manufactured by Toshiba Corporation) at room temperature and humidity of 25 ° C. and 60% humidity. As a result, the image density was high and the resolution without fogging and unevenness was extremely good. A good image was obtained. In continuous image output, there was practically no image deterioration and a sharp high-density image was obtained. Furthermore, when the same image evaluation was performed in a high-temperature and high-humidity environment at a temperature of 35 ° C. and a humidity of 85%, a good image was obtained as in a normal temperature and normal humidity environment.

<Example 2>
The organic resin particles (2) of the present invention were obtained in the same manner as in Example 1, except that 6 g of the hydrophobic spherical silica particles (2) was used as the hydrophobic spherical silica particles in Example 1 above.

  When the particle diameter of the obtained organic resin particles (2) was measured using a Coulter counter (manufactured by Nikka Machine Co., Ltd., aperture 100 μm), the volume average particle diameter (dv) was 9.0 μm, The coarse particle size was small, and the particle size distribution, that is, the ratio (dv / dp) between the volume average particle size and the number average particle size (dp) was 1.21, and the particle size distribution was narrow.

Further, when the volume resistivity value of the organic resin fine particles (2) was measured using a dielectric loss measuring instrument (TR-1100 type, manufactured by Ando Electric Co., Ltd.) under the conditions of a temperature of 25 ° C. and a frequency of 1 kHz, Its volume resistivity was 5.2 × 10 ¹⁰ Ω · cm.

  Further, when the organic resin particles (2) were observed with an optical microscope (1000 times), each particle showed a completely black spherical shape, and no ubiquitous carbon black was observed in the particles.

  Using these organic resin particles (2), a two-component developer was prepared in the same manner as in Example 1, and image evaluation was performed. As a result, the image density was high both at room temperature and normal humidity, and at high temperature and high humidity. A very good image with uniform resolution was obtained. In continuous image output, there was practically no image deterioration and a sharp high-density image was obtained.

<Example 3>
In the said Example 1, the organic resin particle (3) of this invention was obtained by operation similar to Example 1 except the hydrophobic spherical silica particle (3) having been 10 g as a hydrophobic spherical silica particle.

  When the particle diameter of the obtained organic resin particles (3) was measured using a Coulter counter (manufactured by Nikka Kikai Co., Ltd., aperture 100 μm), the volume average particle diameter (dv) was 12.3 μm, The coarse particle size was small, and the particle size distribution, that is, the ratio (dv / dp) between the volume average particle size and the number average particle size (dp) was 1.25, indicating a narrow particle size distribution.

Moreover, when the volume resistivity value of this organic resin particle (3) was measured under conditions of a temperature of 25 ° C. and a frequency of 1 kHz using a dielectric loss measuring device (TR-1100 type, manufactured by Ando Electric Co., Ltd.), Its volume resistivity was 4.9 × 10 ¹⁰ Ω · cm.

  Furthermore, when this organic resin particle (3) was observed with an optical microscope (1000 times), each particle showed a completely black sphere, and no ubiquitous carbon black was observed within the particle.

  Using these organic resin particles (3), a two-component developer was prepared in the same manner as in Example 1, and image evaluation was performed. As a result, the image density was high both at normal temperature and normal humidity, and at high temperature and high humidity. A very good image with uniform resolution was obtained. In continuous image output, there was practically no image deterioration and a sharp high-density image was obtained.

<Comparative Example 1>
In Example 1 above, organic resin particles (4) were obtained in the same manner as in Example 1 except that 6 g of commercially available Aerosil R972 manufactured by Nippon Aerosil Co. was used as the hydrophobic spherical silica particles.

  When the particle diameter of the obtained organic resin particles (4) was measured using a Coulter counter (manufactured by Nikka Machine Co., Ltd., aperture 100 μm), the volume average particle diameter (dv) was 9.5 μm. The particle size distribution was large and the particle size distribution, that is, the ratio (dv / dp) of the volume average particle size to the number average particle size (dp) was 2.80, indicating a wide particle size distribution. .

Moreover, when the volume resistivity value of this organic resin particle (4) was measured under the conditions of a temperature of 25 ° C. and a frequency of 1 kHz using a dielectric loss measuring device (TR-1100 type, manufactured by Ando Electric Co., Ltd.), Its volume resistivity was 5.0 × 10 ¹⁰ Ω · cm.

  Further, when the organic resin particles (4) were observed with an optical microscope (1000 times), each particle showed a black spherical shape, but ubiquitous carbon black was observed in the particles.

  Using this organic resin particle (4), a two-component developer was prepared in the same manner as in Example 1, and image evaluation was performed. As a result, the image density was low under high temperature and high humidity, and the resolution without fogging and unevenness was obtained. A slightly blurred image was obtained.

<Comparative example 2>
In Example 1, organic resin particles (5) were obtained in the same manner as in Example 1 except that 5 g of commercially available Aerosil R974 manufactured by Nippon Aerosil Co. was used as the hydrophobic spherical silica particles.

  When the particle diameter of the obtained organic resin particles (5) was measured using a Coulter counter (manufactured by Nikka Machine Co., Ltd., aperture 100 μm), the volume average particle diameter (dv) was 8.8 μm. The particle size distribution was large and the particle size distribution, that is, the ratio (dv / dp) of the volume average particle size to the number average particle size (dp) was 2.75, indicating a wide particle size distribution. .

Moreover, when the volume resistivity value of this organic resin particle (5) was measured under the conditions of a temperature of 25 ° C. and a frequency of 1 kHz using a dielectric loss measuring device (TR-1100 type, manufactured by Ando Electric Co., Ltd.), Its volume resistivity was 5.1 × 10 ¹⁰ Ω · cm.

  Furthermore, when the organic resin particles (5) were observed with an optical microscope (1000 times), each particle showed a black spherical shape, but ubiquitous carbon black was observed in the particles.

  Using these organic resin particles (5), a two-component developer was prepared in the same manner as in Example 1, and image evaluation was performed. As a result, the image density was low under high temperature and high humidity, and the resolution without fogging and unevenness was obtained. A slightly blurred image was obtained.

<Note>
1) Particle size of hydrophilic spherical silica particles of dispersion obtained in step (A1) 2) Particle size of finally obtained hydrophobic silica particles

Claims (11)

  Organic obtained by suspension polymerization of a monomer composition containing a polymerizable monomer in the presence of a dispersion stabilizer in which hydrophobic spherical silica particles are dispersed in an aqueous medium in the presence of a hydrophilic organic compound. A method for producing resin particles, wherein the silica particles have a particle size (volume-based median diameter) in the range of 0.005 to 1.00 μm (5 to 1000 nm), and the particle size distribution D90 / D10 is 3 or less. A method for producing organic resin particles, comprising hydrophobic spherical silica particles having an average circularity of 0.8 to 1 and a hydrophobicity of 60% or more. The hydrophobic spherical silica particles are
(A1) a step of obtaining hydrophilic spherical silica particles substantially consisting of SiO ₂ units by hydrolyzing and condensing a tetrafunctional silane compound, a partially hydrolyzed condensation product thereof, or a mixture thereof;
(A2) R ¹ SiO _3/2 units (wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms) are introduced onto the surface of the hydrophilic spherical silica particles. Process,
(A3) Further, R ² ₃ SiO _1/2 units (wherein each R ² is the same or different and is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms) on the surface of the hydrophilic spherical silica particles. The method for producing organic resin particles according to claim 1, wherein the method comprises the step of: The hydrophobic spherical silica particles are
(A1) General formula (I):
Si (OR ³ ) ₄ (I)
(Wherein each R ³ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms), a tetrafunctional silane compound, a partial hydrolysis product thereof, or a mixture thereof, In the presence of the substance, a mixed solvent dispersion of hydrophilic spherical silica particles substantially consisting of SiO ₂ units is obtained by hydrolysis and condensation in a mixed liquid of a hydrophilic organic solvent and water,
(A2) In the mixed solvent dispersion of the obtained hydrophilic spherical silica particles, the general formula (II):
R ¹ Si (OR ⁴ ) ₃ (II)
Wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and each R ⁴ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms. trifunctional silane compound, a partial hydrolysis product, or by treating the surface of the hydrophilic spherical silica particles was added to these mixtures, the surface of the hydrophilic spherical silica particles R ¹ SiO 3 _/ Introducing ₂ units (R ¹ is as described above) to obtain a mixed solvent dispersion of the first hydrophobic spherical silica particles,
(A3) To the resulting mixed solvent dispersion of the first hydrophobic spherical silica particles, the general formula (III):
R ² ₃ SiNHSiR ² ₃ (III)
(In the formula, each R ² is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms)
A silazane compound represented by the general formula (IV):
R ² ₃ SiX (IV)
(Wherein R ² is as defined in the general formula (III), X is an OH group or a hydrolyzable group), or a mixture thereof, The surface of the first hydrophobic spherical silica particles is treated with the silazane compound, the monofunctional silane compound, or a mixture thereof, and the surface of the first hydrophobic spherical silica fine particles is subjected to R ² ₃ SiO _1/2. by introducing the unit (R ² is as defined in formula (III)), a hydrophobic spherical silica particles obtained as the second hydrophobic silica particles, organic according to claim 1 or 2 A method for producing resin particles.   The manufacturing method of the organic resin particle of Claim 2 or 3 including a concentration process between the manufacturing processes (A2) and (A3) of the said silica particle.   The obtained organic resin particles have a volume average particle size of 0.1 to 500 μm and a particle size distribution (ratio of volume average particle size / number average particle size) of 1.6 or less. Item 5. The method for producing organic resin particles according to any one of Items 1 to 4.   The monomer composition is a composition containing a polymerizable monomer and at least one selected from a (co) polymer, a colorant, and other additives. The manufacturing method of the organic resin particle of any one of 1-5.   The method for producing organic resin particles according to claim 6, wherein the monomer composition is a composition containing a polymerizable monomer and a colorant. Hydrophobic spherical silica particles are dispersed in an aqueous medium in the presence of a hydrophilic organic compound, a dispersion stabilizer for suspension polymerization of the polymerizable monomer, the hydrophobic spherical silica particles, the particles The diameter (volume-based median diameter) is in the range of 0.005 to 1.00 μm (5 to 1000 nm), the value of the particle size distribution D90 / D10 is 3 or less, the average circularity is 0.8 to 1, and A dispersion stabilizer for suspension polymerization of a polymerizable monomer, characterized by being hydrophobic spherical silica particles having a degree of hydrophobicity of 60% or more. The dispersion stabilizer according to claim 8 , wherein the hydrophilic organic compound is an alcohol having 1 to 3 carbon atoms. The dispersion stabilizer according to claim 8 or 9 , wherein the aqueous medium is water or a water / alcohol mixture. (A1) By substantially hydrolyzing and condensing a tetrafunctional silane compound, a partially hydrolyzed condensation product thereof, or a mixture thereof, SiO 2 ₂ Obtaining hydrophilic spherical silica particles composed of units;
(A2) On the surface of the hydrophilic spherical silica particles, R ¹ SiO _3/2 Unit (in the formula, R ¹ Is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms),
(A3) R is further added to the surface of the hydrophilic spherical silica particles. ² ₃ SiO _1/2 Unit (where each R ² Are the same or different and are substituted or unsubstituted monovalent hydrocarbon groups having 1 to 6 carbon atoms)
Hydrophobic spherical silica particles are produced by a method comprising, and the hydrophobic spherical silica particles are dispersed in an aqueous medium in the presence of a hydrophilic organic compound. The manufacturing method of the dispersion stabilizer for suspension polymerization of the polymerizable monomer as described in a term.