JP2016142811A - Composite particle, toner external additive and method for producing composite particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite particle having high adhesion strength of fine particles to core particles, and capable of securing excellent charge amount and high fluidity.SOLUTION: The composite particles comprises core particles and fine particles. The principal component of the core particle is one of an organic material and an inorganic material. The fine particles are present on the core particles, and the principal component of the fine particle is the other of the organic material and the inorganic material. The average particle size of the core particles is 80-300 nm, and the coefficient of variation of average particle size is 2-10%. The average particle size of fine particle is 5-30 nm, and the average particle size of the fine particle/the average particle size of the core particle is 0.016-0.25. The composite particle has: an average particle size of 90-350 nm. In the composite particle; a ratio β/βof multipliers in a volume resistance (α×10) and a surface resistance (α×10) is 0.7-1.4; and the number variation of the fine particle existing on the core particle is 0.5 to 5% before and after irradiating a dispersion using water as a dispersion medium and including composite particles of 1 wt.% with an ultrasonic wave having an output of 110 W and a frequency of 31 kHz for 30 minutes.SELECTED DRAWING: Figure 1

Description

  The present invention relates to, for example, applicable composite particles as a component of a toner external additive used externally to an electrophotographic toner, a method for producing the same, and an external additive for toner containing the composite particles. .

Since the composite particle has a portion formed from an organic material and a portion formed from an inorganic material, both the processability derived from the organic material and the characteristics derived from the inorganic material can be combined. It is a functional material that is expected to be applied to various uses that take advantage of material properties.
As types of composite particles, so-called core-shell type particles having a structure in which the surface of resin particles constituting the core portion is coated with an inorganic material layer constituting the shell portion (for example, see Patent Documents 1 to 4), organic materials Known so-called raspberry type particles (for example, refer to Patent Documents 5 to 9) having a structure in which fine particles of small particle size formed from an inorganic material are attached to the surface of the formed core particle of large particle size are known. Those having various shapes and configurations have been developed depending on the application.

Here, when the composite particles are used as a component of an external toner additive that is externally added to the toner for electrophotography, the composite particles are subjected to shearing force and friction during contact with members in an image forming apparatus such as a copying machine. Receive various stresses such as strength. When applying composite particles to applications such as electrophotographic toner, the charge amount of the composite particles needs to be controlled within an appropriate range according to the application, and for electrophotographic toners to which composite particles are applied. On the other hand, it is necessary to provide fluidity according to the application.
As described above, the composite particles applied to uses such as an electrophotographic toner have sufficient strength to withstand the stress as described above and a good charge amount, and an electrophotographic image using the composite particles is applied. Appropriate fluidity according to the application is required for the toner for use.

JP 2012-189881 JP 2005-173480 A JP 2012-13776 JP 2012-073468 Special Table 2007-504307 JP 2002-131976 JP 2005-202131 A JP 2005-202133 A JP 2014-065014 A

However, conventional composite particles have a problem that it is difficult to meet the above requirements.
In the core-shell type composite particles disclosed in Patent Documents 1 to 4, since the flexibility of the spherical organic particles constituting the core is high, the shape of the core part easily changes when subjected to stress as described above. There is a possibility that the spherical shape cannot be maintained. When the composite particles cannot maintain a spherical shape, the fluidity of the composite particles decreases, and it becomes difficult to impart an appropriate level of fluidity to the electrophotographic toner.
Since the conventional raspberry type composite particles disclosed in Patent Documents 5 to 8 have a structure in which fine particles are simply attached on the core particles, the adhesion strength of the fine particles on the core particles is low. When the adhesion strength of the fine particles on the core particles is low, the initial characteristics are difficult to maintain because the fine particles are easily detached from the core particles when subjected to the stress as described above.
In contrast, the conventional raspberry type composite particles disclosed in Patent Document 9 have a structure in which fine particles formed from an inorganic material and fine particles formed from an organic material are combined with an organic hydrophobizing agent. It is considered that the adhesion strength between the particles is higher than the conventional raspberry type composite particles disclosed in Patent Documents 5 to 8 described above. However, in the conventional raspberry type composite particles disclosed in Patent Document 9, many organic components derived from the organic hydrophobizing agent are exposed on the surface. Since the organic component has a higher charge amount than the inorganic component, if a large amount of the organic component is present on the surface of the composite particle, it becomes difficult to control the charge amount of the composite particle.

On the other hand, for example, raspberry-type composite particles having a structure in which nano-sized inorganic particles are attached to the surface of core particles formed from an organic polymer are fine irregularities formed by inorganic particles present on the surface. It is utilized as a water-repellent material because it exhibits water repellency by the so-called lotus leaf effect based on its shape. Further, such raspberry type composite particles are utilized as a catalyst carrier because of their large specific surface area compared to spherical particles having no irregularities on the surface. As described above, the raspberry-type composite particles are also attracting attention because there is room for expanding the application to new applications due to the characteristics derived from the structure and surface shape.
Therefore, in order to further utilize the raspberry type composite particles and expand the application range thereof, it is necessary to solve the above-mentioned problems.

  The present invention has been made to solve the above-described problems, and has high adhesion strength of fine particles onto the core particle, and can provide a composite particle capable of securing a good charge amount and high fluidity, a method for producing the same, and Another object of the present invention is to provide an external additive for toner containing the composite particles.

  In order to solve the above-described problems, the present invention has the following configuration.

(Configuration 1)
In composite particles comprising core particles and fine particles,
The main component of the core particle is one of an organic material and an inorganic material,
When the fine particles are present on the core particles and the main component of the core particles is an organic material, the main component of the fine particles is an inorganic material, and the main component of the core particles is an inorganic material. In some cases, the main component of the fine particles is an organic material,
The average particle diameter of the core particles is 80 nm or more and 300 nm or less, and the coefficient of variation of the average particle diameter of the core particles is 2% or more and 10% or less,
The average particle size of the fine particles is 5 nm or more and 30 nm or less, and the ratio of the average particle size of the fine particles to the average particle size of the core particles is 0.016 or more and 0.25 or less,
The composite particles have an average particle size of 90 nm or more and 350 nm or less,
A multiplier ratio β ₁ / β _{2 in} the volume resistance ρv = α ₁ × 10 ^β1 (Ω · cm) and surface resistance ρs = α ₂ × 10 ^β2 (Ω / cm ² ) of the composite particles is 0.7 or more. 4 or less,
The fine particles present on the core particles before and after irradiating the composite particle dispersion in which the composite particles are dispersed in water so as to be 1% by weight under the conditions of an output of 110 W and a frequency of 31 kHz for 30 minutes. Composite particles having a number change of 0.5% or more and 5% or less.

(Configuration 2)
The composite particle according to Configuration 1, wherein the composite particle has a relative dielectric constant of 2 or more and 300 or less.

(Configuration 3)
The composite particle according to Configuration 1 or 2, wherein a coverage of the fine particles on the surface of the core particle is 5% or more and less than 68%.

(Configuration 4)
The composite particle according to any one of configurations 1 to 3, wherein the core particle is formed of an organic material, and the fine particle is formed of an inorganic material.

(Configuration 5)
Furthermore, the composite particle according to Configuration 4, comprising fine particles formed from an organic material.

(Configuration 6)
The composite particle according to Configuration 4 or 5, wherein the inorganic material is selected from the group consisting of silica, titania, cerium oxide, and strontium titanate.

(Configuration 7)
The composite particle according to any one of configurations 1 to 3, wherein the core particle is formed of an inorganic material, and the fine particle is formed of an organic material.

(Configuration 8)
Furthermore, the composite particle of the structure 7 provided with the microparticles | fine-particles formed from an inorganic material.

(Configuration 9)
The composite particle according to Configuration 7 or 8, wherein the inorganic material is selected from the group consisting of silica, titania, cerium oxide, and strontium titanate.

(Configuration 10)
10. The composite particle according to any one of configurations 1 to 9, wherein the composite particle includes an inorganic material layer that covers the surface of the core particle and the fine particle.

(Configuration 11)
11. An external toner additive comprising the composite particles according to any one of configurations 1 to 10.

(Configuration 12)
In a method for producing composite particles comprising core particles and fine particles,
The fine particles adhere to the surface of the core particles from a dispersion liquid containing the core particles mainly composed of one of an organic material and an inorganic material and the fine particles mainly composed of either the organic material or the inorganic material. A particle adhering body forming step for forming the particle adhering body,
A silane coupling agent and a basic substance that binds to and interacts with one of the core particles and the fine particles are added to the dispersion in which the particle adhering body is formed, and the core particles are added. And a composite particle forming step of forming the composite particle having the fine particles immobilized on the surface thereof.

According to the composite particle according to the present invention, in the composite particle comprising the core particle and the fine particle, the main component of the core particle is one of an organic material and an inorganic material, and the fine particle exists on the core particle, The main component of the fine particle is either the organic material or the inorganic material, that is, when the main component of the core particle is an organic material, the main component of the fine particle is the inorganic material, and the main component of the core particle Is an inorganic material, the main component of the fine particles is an organic material, the average particle diameter of the core particles is 80 nm or more and 300 nm or less, and the variation coefficient of the average particle diameter of the core particles is 2% or more and 10%. The average particle diameter of the fine particles is 5 nm or more and 30 nm or less, and the ratio of the average particle diameter of the fine particles to the average particle diameter of the core particles is 0.016 or more and 0.25 or less. Child diameter is not less 90nm or 350nm or less, the composite particles ^{_{ρv = α 1 × 10 β1 (}} Ω · cm) and the surface resistivity ^{_{ρs = α 2 × 10 β2 (}} Ω / cm 2) Ratio of the multiplier in the beta ₁ / beta ₂ Before and after irradiating the composite particle dispersion liquid in which the composite particles are dispersed in water so that the composite particles are 1% by weight under the conditions of an output of 110 W and a frequency of 31 kHz for 30 minutes. The change in the number of fine particles present on the core particles is 0.5% or more and 5% or less.
The composite particles having the above physical properties have the following effects.
(I) The composite particles are present in the form of fine particles on the surface of the core particles, and the change in the number of fine particles existing on the surface of the core particles before and after ultrasonic irradiation under a predetermined condition is extremely small. The adhesion strength of the fine particles on the core particles is high compared to the conventional composite particles simply deposited on the top. Since the adhesion strength of the fine particles onto the core particles is high, the fine particles are not easily detached from the core particles even when subjected to various stresses such as shearing force.
(Ii) The composite particles have a volume resistance ρv and a surface resistance ρs in a predetermined numerical range, and a relative dielectric constant is in a predetermined range. Good charge amount can be secured. This good charge amount can be maintained for a long period of time because the adhesion strength of the fine particles onto the core particles is high and the fine particles are not easily detached from the core particles.
(Iii) Since the core particles and the fine particles have an average particle diameter in a predetermined numerical range, a ratio of the average particle diameter, and a covering ratio in a predetermined numerical range, for example, as a component such as an external additive for toner When used, the toner and the composite particles are always in contact with the toner and fine particles present on the composite particles, so that high fluidity can be secured as an initial characteristic without lowering the rolling property. The composite particles having high fluidity can be favorably applied as a component such as an external additive for toner. High fluidity can be maintained for a long period of time because the adhesion strength of the fine particles onto the core particles is high and the fine particles are not easily detached from the core particles.
Therefore, the composite particles according to the present invention have high adhesion strength of fine particles onto the core particles, and can secure a good charge amount and high fluidity.

According to the method for producing composite particles according to the present invention, in the method for producing composite particles comprising core particles and fine particles, the core particles, organic materials, and inorganic materials mainly composed of one of an organic material and an inorganic material are used. A particle adhering body forming step of forming a particle adhering body in which fine particles adhere to the surface of the core particle from a dispersion liquid containing fine particles containing either one of the main components as a main component; And forming a composite particle in which fine particles are immobilized on the surface of the core particle by adding a silane coupling agent and a basic substance that binds to and interacts with either one of the fine particles And comprising.
In the particle adhesion formation process, fine particles are present on the core particles by hetero-aggregation to form a particle adhesion body in which the particles are electrostatically adhered to the surface of the core particles. In the composite particle formation process, silane coupling is performed. By the action of the agent, composite particles in which fine particles are immobilized on the surface of the core particles are formed. This composite particle can have each of the physical properties described above.
Therefore, according to the method for producing composite particles according to the present invention, it is possible to produce composite particles that have high adhesion strength of fine particles onto the core particles, and can ensure a good charge amount and high fluidity.

  The toner external additive according to the present invention includes the composite particles described above. Therefore, this external additive for toner has a high adhesion strength of fine particles onto the core particle, and can secure a good charge amount and high fluidity, so it has a higher deterioration resistance than conventional ones and has been used for a long time. The adhesion between the additive and the toner particles can be maintained, the transfer efficiency can be maintained at a high level, and the external additive for toner is not easily released from the toner particles, so that image defects caused by member contamination are suppressed and stable. Image quality can be provided.

It is a schematic diagram which shows the external appearance of a composite particle based on the image (SEM image) by a scanning electron microscope. FIG. 2 is an enlarged cross-sectional view schematically showing a part of the surface structure of the composite particle shown in FIG. 1. It is a schematic diagram for demonstrating how to obtain | require the average particle diameter of the composite particle shown in FIG. It is a schematic diagram for demonstrating how to obtain | require the average particle diameter of the particle | grains which comprise some composite particles shown in FIG. It is a circuit diagram for measuring the volume resistance of a composite particle. It is a circuit diagram for measuring the surface resistance of composite particles.

  Hereinafter, embodiments of the present invention will be specifically described. In addition, the following embodiment is one form at the time of actualizing this invention, Comprising: This invention is not limited to the range.

Embodiment 1 FIG.
A. Composite Particle The composite particle according to the first embodiment includes core particles and fine particles. The main component of the core particle is an organic material (hereinafter, the core particle may be referred to as an organic core particle), the fine particle is present on the core particle, and the main component of the fine particle is an inorganic material (hereinafter, the fine particle is Sometimes called inorganic fine particles). The composite particles also have the following physical properties (1) to (6).
Physical property (1): The average particle diameter of the organic core particles is 80 nm or more and 300 nm or less.
Physical property (2): The variation coefficient of the average particle diameter of the organic core particles is 2% or more and 10% or less.
Physical property (3): The average particle diameter of the inorganic fine particles is 5 nm or more and 30 nm or less, and the ratio of the average particle diameter of the inorganic fine particles to the average particle diameter of the organic core particles (hereinafter, the average particle diameter of the inorganic fine particles / the ratio of the organic core particles) The average particle diameter is 0.016 or more and 0.25 or less.
Physical property (4): The average particle diameter of the composite particles is 90 nm or more and 350 nm or less.
Physical property (5): The ratio β ₁ / β ₂ of the multiplier in the volume resistance ρv = α ₁ × 10 ^β1 (Ω · cm) and the surface resistance ρs = α ₂ × 10 ^β2 (Ω / cm ² ) of the composite particles is 0. 7 or more and 1.4 or less.
Physical property (6): On the organic core particle before and after irradiating the composite particle dispersion liquid in which the composite particle is 1% by weight with ultrasonic waves for 30 minutes under the conditions of an output of 110 W and a frequency of 31 kHz. The number change of the inorganic fine particles present is 0.5% or more and 5% or less.
In the present specification, dimensions such as the average particle diameter are included in the physical properties.

  The organic material forming the organic core particles is preferably a material having the mechanical strength required for the organic core particles constituting the particle center of the composite particles. Polyolefin such as (meth) acrylic resin, polystyrene, polyethylene, Examples thereof include polyesters such as vinyl chloride and polyethylene terephthalate, and copolymers thereof, epoxy resins, and urethane resins, but are not limited thereto.

  Inorganic materials that form inorganic fine particles include silicon oxide (silica), titanium oxide (titania), zirconium oxide (zirconia), and oxidation in consideration of the use of composite particles and the type of organic material that forms organic core particles. Aluminum (alumina), cerium oxide, tungsten oxide, antimony oxide, copper oxide, tellurium oxide, manganese oxide, tin oxide, indium oxide, beryllium oxide, lead oxide, bismuth oxide, barium titanate, strontium titanate, magnesium titanate, It can be appropriately selected from inorganic materials such as silicon nitride and carbon nitride. In particular, the inorganic material forming the inorganic fine particles is preferably selected from the group consisting of silica, titania, cerium oxide, and strontium titanate, but is not limited thereto.

Here, the shapes of the composite particles, the organic core particles, and the inorganic fine particles, and the relationship between the organic core particles and the inorganic fine particles will be described.
FIG. 1 is a schematic view showing the appearance of the composite particles based on the SEM image, and FIG. 2 is an enlarged cross-sectional view schematically showing a part of the surface structure of the composite particles shown in FIG.
For example, as shown in FIG. 1, the composite particles are so-called raspberry type particles having a spherical shape as a whole, and one organic core particle A having a large particle diameter constituting the particle center and the organic It is roughly composed of a plurality of inorganic fine particles B having a smaller particle diameter than the organic core particles A, which are fixed and united on the surface of the core particles A.

Since both the organic core particle A and the inorganic fine particle B are manufactured by the manufacturing method described later, they have a spherical shape.
As shown in FIG. 1, a plurality of inorganic fine particles B are immobilized on the surface of the organic core particle A in such a manner as to constitute at least a part of the surface of the organic core particle A. In this embodiment, it is desirable that the plurality of inorganic fine particles B constituting at least a part of the surface of the organic core particle A be fixed uniformly without being biased over the entire surface of the organic core particle A. The presence of the inorganic fine particles B that are unevenly immobilized on a part of the surface of the organic core particle A causes the characteristics of the composite particles to be biased, and because the composite particles cannot maintain a spherical shape. This is because the fluidity required for the composite particles may be lowered, which is not preferable. Further, as long as it is not biased to a part of the surface of the organic core particle A, a part of the surface of the organic core particle A may be in a state where the inorganic fine particles B are exposed.

  The organic core particle A is C1, C2, C3,... Cn (n is 1 or more) in FIG. As shown by (integer integer), organic particles mainly composed of different kinds of organic materials may be combined to constitute one organic core particle as a whole. Moreover, each particle | grains united in order to comprise one organic core particle may have a different particle diameter.

  The above physical properties (1) to (4) are related to the average particle diameters of the composite particles, the organic core particles A, and the inorganic fine particles B, and these average particle diameters are all determined by SEM image observation. .

Hereinafter, a method for obtaining the average particle size of the composite particles by SEM image observation will be described.
FIG. 3 is a schematic diagram for explaining how to obtain the average particle diameter of the composite particles shown in FIG. 1, and FIG. 4 is an average particle of the particles that constitute a part of the composite particles shown in FIG. It is a schematic diagram for demonstrating how to obtain | require a diameter.
In SEM image observation, the SEM images of a total of 100 composite particles are binarized while changing the field of view of the SEM image, and binarized images of the obtained composite particles are obtained. Based on such a binarized image, as shown in FIG. 3, when it is assumed that the circular contour of the composite particle cross section corresponds to the surface of the organic core particle A, the surface of the organic core particle A is The assumed maximum inscribed circle (shown by an inner broken line in FIG. 3) having a diameter DA (average particle diameter of the organic core particle A) of the circular contour. The substantially circular portion protruding from the assumed maximum inscribed circle corresponds to the inorganic fine particles B existing on the surface of the organic core particle A. Therefore, it can be assumed that the portion of the substantially circular portion that protrudes from the assumed maximum inscribed circle is the portion farthest from the assumed maximum inscribed circle corresponding to the outer surface of the composite particle. It can be represented by an assumed maximum circumscribed circle (indicated by an outer broken line in FIG. 3) having a diameter D (average particle diameter of the composite particles) of a portion farthest from the assumed maximum inscribed circle.
Further, how to obtain the average particle diameter before the organic core particle A and the inorganic fine particle B are combined will be described.
In this case as well, the SEM image observation is used, and the SEM images for the total 100 organic core particles A or inorganic fine particles B are binarized while changing the field of view of the SEM images. A binarized image of the obtained organic core particle A or inorganic fine particle B is obtained. From such a binarized image, the diameter DA of the organic core particles A or the diameter DB of the inorganic fine particles B can be obtained. That is, as shown in FIG. 4 based on the binarized image, at least two strings X and Y are arbitrarily drawn in a substantially circular portion corresponding to the particle surface. As shown in FIG. 4, the distance between the intersection of the orthogonal lines (perpendicular lines) to these two strings X and Y and the position farthest from the intersection in the substantially circular portion is the radius DA / of the organic core particle A. 2 or the radius DB / 2 of the inorganic fine particle B, the diameter DA of the organic core particle A (the average particle diameter of the organic core particle A) or the diameter DB ( The average particle diameter of the inorganic fine particles B can be determined.

Hereinafter, the physical properties (1) to (4) will be described individually.
The numerical range of the average particle diameter of the organic core particle A having the physical properties (1) is, for example, practically appropriate when the composite particle is used as a constituent component such as an external additive for toner. The particle size range of the organic core particle A before immobilization on the top is shown.
As described above, the average particle diameter of the organic core particle A is 80 nm or more and 300 nm or less, and preferably 80 nm or more and 200 nm or less.
Here, when the average particle diameter of the organic core particles A is less than 80 nm, particles having a small particle diameter are also mixed. Therefore, composite particles including organic core particles having a small particle diameter are, for example, a toner having a large particle diameter. This is not preferable in that the spacer effect required as an external additive cannot be sufficiently exhibited. When the average particle size of the organic core particle A exceeds 300 nm, particles having a very large particle size are also mixed. Therefore, the average particle size of the composite particles including the average particle size of the inorganic fine particles B is, for example, for toner Since it becomes too large as a constituent component of the external additive, it is not preferable in that the adhesion force of the toner external additive to the toner particles is reduced.

The numerical range of the coefficient of variation of the average particle diameter of the organic core particle A having the physical properties (2) is, for example, organic in the inorganic fine particles B, which is practically appropriate when the composite particle is used as a component such as an external additive for toner. The range of the dispersion | variation in the average particle diameter of the organic core particle A before fixing on the core particle A is shown. This coefficient of variation is calculated from standard deviation of measured value distribution of particle diameter of organic core particle A ÷ average particle diameter × 100.
Here, when the variation coefficient of the average particle diameter of the organic core particle A exceeds 10%, the dispersion of the particle diameter of the organic core particle A is too large. For example, the composite particle is used as a component such as an external additive for toner. When used, it is not preferable in that the adhesion of the composite particles to the toner is not stable and the toner characteristics are not stable.

The numerical range of the average particle diameter of the inorganic fine particle B of the physical property (3) / the average particle diameter of the organic core particle A is practically appropriate when, for example, the composite particle is used as a component such as an external additive for toner. The balance between the average particle diameter of the inorganic fine particles B and the average particle diameter of the organic core particles A before immobilization of the inorganic fine particles B on the organic core particles A is shown.
The particle size of the inorganic fine particles having physical properties (3) is 5 nm or more and 30 nm or less, and the average particle size of the inorganic fine particles B / the average particle size of the organic core particles A is 0.016 or more and 0.25 or less as described above. Preferably, it is 0.018 or more and 0.2 or less.
Here, if the particle diameter of the inorganic fine particles is less than 5 nm, it becomes difficult to exist in the form of primary particles, and it cannot be uniformly present in the form of core particles. On the other hand, when the thickness exceeds 30 nm, the fine particles are easily detached when subjected to stress, and it is not preferable in that fluidity cannot be secured as an external additive for toner. Further, when the average particle diameter of the inorganic fine particles B / the average particle diameter of the organic core particles A is less than 0.016, the average particle diameter of the inorganic fine particles B is extremely small with respect to the average particle diameter of the organic core particles A. The particle size is poorly balanced, and the composite particles in the case where the average particle diameter of the organic core particles A takes a value in the vicinity of 80 nm are not preferable because, for example, it is difficult to obtain a large particle diameter capable of exhibiting the spacer effect. When the average particle diameter of the inorganic fine particles B / the average particle diameter of the organic core particles A exceeds 0.25, the average particle diameter of the inorganic fine particles B is extremely large with respect to the average particle diameter of the organic core particles A. This is not preferable because the size balance is poor, the core particles and the fine particles are easily detached when subjected to stress, and fluidity cannot be secured as an external additive for toner.

The numerical range of the average particle diameter of the composite particles having the physical properties (4) indicates a particle size range of the composite particles that is practically appropriate when the composite particles are used as a component such as an external additive for toner.
As described above, the average particle size of the composite particles having physical properties (4) is 90 nm or more and 350 nm or less, and preferably 90 nm or more and 250 nm or less.
Here, if the numerical range of the average particle diameter of the composite particles is less than 90 nm, the composite particles are too small. For example, the composite particles are not preferable in that they do not easily exert the spacer effect. If the numerical range of the average particle diameter of the composite particles exceeds 350 nm, it is not preferable because, for example, the composite particles are too large as a component such as an external additive for toner.

  In addition, each average particle diameter of the composite particle, the organic core particle A, and the inorganic fine particle B related to the physical properties (1) to (4) is also obtained by a method (for example, dynamic light scattering method) other than the above-described SEM image observation. be able to. For specific composite particles other than the composite particles of the present invention, even if the average particle diameter obtained by a method other than the SEM image observation described above is different from the numerical range of the physical properties (1) to (4), When the average particle diameter obtained by the above-mentioned SEM image observation is included in the numerical range of physical properties (1) to (4), the specific composite particles have physical properties (1) to (4). It can be recognized as having.

As described above, the composite particles having the physical properties (1) to (4) further have a volume resistance ρv = α ₁ × 10 ^β1 (Ω · cm) and a surface resistance ρs = α ₂ × 10 ^β2 ( The physical property (5) is such that the multiplier ratio β ₁ / β ₂ in Ω / cm ² ) is 0.7 or more and 1.4 or less. Here, the multiplier ratio β ₁ / β ₂ may be referred to as a resistance ratio ρr. α ₁ and α ₂ are real numbers of 1 or more and less than 10, β ₂ and β ₂ are integers of 0 or more and 20 or less, and α ₁ , α ₂ , β ₂ , and β ₂ may each be the same numerical value. Also, different numerical values may be used.
The numerical range of the resistance ratio ρr of the composite particle having physical properties (5) is, for example, the volume resistance ρv of the composite particle, which is practically appropriate when the composite particle is used as a constituent component such as an external additive for toner, and the composite particle. This shows the balance with the surface resistance ρs. The volume resistance ρv of the composite particle depends on the electrical resistance of the organic material forming the organic core particle A and the inorganic material forming the fine particle B. The surface resistance ρs of the composite particle forms the surface of the composite particle. It depends on the electrical resistance specific to the material. Therefore, the resistance ratio ρr is determined by the balance of both resistance values. If the balance between the volume resistance ρv of the composite particles and the surface resistance ρs of the composite particles is appropriate and the resistance ratio ρr is in the above numerical range, the charge charged on the composite particles is transferred from the entire surface of the composite particles to other particles, etc. Therefore, the composite particles have good charging characteristics such as charging speed, charge amount (μC / g), and stability.

As described above, β ₁ / β ₂ is 0.7 or more and 1.4 or less in the volume resistance ρv and the surface resistance ρs of the composite particles having the physical properties (5). In such composite particles, the volume resistance ρv depends on the electrical resistances of the organic material forming the organic core particle A and the inorganic material forming the inorganic fine particle B, and the surface resistance ρs is the surface of the composite particle. Depends on the electrical resistance specific to the material forming. Since the electrical resistance of the inorganic material forming the inorganic fine particles B is lower than that of the organic material forming the organic core particles A, the composite particles having the above-described configuration have a high volume resistance ρv and a low surface resistance ρs. In general, the electric charge charged on the particle surface enters the inside of the particle or travels through the particle surface, and from the other surface of the particle (for example, the contact surface with the toner particle to which the composite particle is externally added) to other particles. It is thought that it will shift to. In the composite particle including the organic core particle A and the inorganic fine particle B, the electric charge charged on the surface does not enter the inside of the composite particle (part of the organic core particle A), but the surface of the composite particle (mainly the surface of the inorganic fine particle B). It is estimated that the surface charge of the composite particle is small, the internal charge of the composite particle is increased, and the uniformity of the charge held by the composite particle is impaired. For this reason, it is important that the relationship between the volume resistance ρv and the surface resistance ρs is in an appropriate numerical range of the physical property (5).
Here, when the resistance ratio ρr is less than 0.7, the surface resistance ρs of the composite particles is extremely small with respect to the volume resistance ρv, so that the surface charge of the composite particles is likely to leak to the outside, and the charge amount of the composite particles is reduced. This is not preferable because it cannot be maintained within an appropriate range. When the resistance ratio ρr exceeds 1.4, on the contrary, the surface resistance ρs of the composite particle is extremely larger than the volume resistance ρv. For example, when the composite particle is used as a component of the external additive for toner, the composite particle Overcharge (charge-up) is likely to occur on the surface of the surface, which may lead to image degradation, and the uniformity of the charge held by the composite particles is impaired due to leakage of surface charges to the outside, etc. This is not preferable because the amount cannot be maintained within an appropriate range.

Here, a method for measuring the volume resistance ρv (Ω · cm) and the surface resistance ρs (Ω / cm ² ) of the composite particles necessary for obtaining the resistance ratio ρr of the composite particles will be described.
FIG. 5 is a circuit diagram for measuring the volume resistance of the composite particles, and FIG. 6 is a circuit diagram for measuring the surface resistance of the composite particles.
<Measurement of volume resistance>
First, composite particles and a thermosetting epoxy resin are added to methanol, and the composite particles are dispersed and kneaded in a thermosetting epoxy resin to obtain a kneaded product. Thereafter, the kneaded product is crushed with a pestle and a mortar for a predetermined time to obtain a gel-like substance. The obtained gel-like substance is poured into a mold, pressed and molded, and the molded product is dried to obtain pellets composed of composite particles and a composite of epoxy resin.
A main electrode is attached to one surface of the pellet, a counter electrode is attached to the opposite surface with silver paste, and a guard electrode is attached to the surface surrounding the main electrode with silver paste on one surface where the main electrode is attached, for volume resistance measurement shown in FIG. A circuit is constructed and the volume resistance of the pellet is determined. Perform the same measurement by changing the compounding ratio of composite particles and epoxy resin in the pellet, draw a calibration curve based on the change in volume resistance with respect to the epoxy resin ratio, and the value of the intercept of the coordinate axis where this calibration curve intersects (epoxy resin Is calculated as the volume resistance (Ω · cm) of the composite particles.
<Measurement of surface resistance>
For the surface resistance, the same pellets as described above are used. A main electrode and a counter electrode are attached to one surface of the pellet, and a guard electrode is attached to the opposite surface with silver paste to form a surface resistance measuring circuit shown in FIG. 6, and the surface resistance of the pellet is obtained.
In this case as well, the same measurement is performed by changing the compounding ratio of the composite particles and the epoxy resin into the pellet, and a calibration curve is drawn based on the change in surface resistance with respect to the ratio of the epoxy resin, and the intercept of the coordinate axis where the calibration curve intersects (Surface resistance when the ratio of epoxy resin is 0%) is calculated as the surface resistance (Ω / cm ² ) of the composite particles.

  The resistance ratio ρr of the composite particles having the physical property (5) can be obtained by a method other than the method of measuring using the measurement circuit shown in FIGS. For specific composite particles other than the composite particles of the present invention, when the resistance ratio ρr determined by a method other than the method of measuring using the measurement circuit shown in FIGS. 5 and 6 is different from the numerical range of the physical property (5) Even when the specific composite particles are obtained by the method of measuring using the measurement circuit shown in FIG. 5 and FIG. 6 and the resistance ratio ρr is included in the numerical range of the physical properties (5), These composite particles can be recognized as having physical properties (5).

In addition, if the resistance ratio ρr of the composite particle having the physical property (5) is in the above-described numerical range, the composite particle has good charging characteristics such as charging speed, charge amount (μC / g), and stability thereof.
A good charge amount of the composite particles is from −300 to −100, preferably from −250 to −150.
The charge amount of the composite particles can be measured by the following method.
First, ferrite particles coated with styrene / methyl methacrylate resin are weighed in a plastic plastic container with a lid, and then the composite particles are weighed in a state of being placed on the ferrite particles. After that, it was allowed to stand under normal temperature and normal humidity (23 ° C./50% RH) and seasoned for 24 hours, and then stirred and shaken with a turbuler mixer for 3 minutes. Give the load to be generated. The charge amount (μC / g) of the particles is measured with a flying charge measuring device (electric field flying charge measuring device II-DC electric field (trade name), manufactured by DIT Corporation).

As described above, the composite particles having the physical properties (1) to (5) are further subjected to the conditions of 110 W output and 31 kHz frequency in the composite particle dispersion in which the composite particles are dispersed in water so that the composite particles are 1% by weight. Thus, the physical property (6) is that the number change of the inorganic fine particles B existing on the surface of the organic core particles A before and after the irradiation with ultrasonic waves for 30 minutes is 0.5% or more and 5% or less.
The numerical range of the number change of the inorganic fine particles B immobilized on the surface of the organic core particle A before and after the ultrasonic irradiation of the physical property (6) is, for example, when the composite particles are used as a constituent component such as an external additive for toner. The adhesion strength of the inorganic fine particles B onto the organic core particles A, which is practically appropriate, is shown.
The change in the number of physical properties (6) is 0.5% or more and 5% or less as described above.
Here, when the number change exceeds 5%, the adhesion strength of the inorganic fine particles B onto the organic core particles A is low, and the inorganic fine particles B are likely to be detached. When used as a component, it is not preferable because it causes toner deterioration and image deterioration.

Here, how to obtain the change in the number of physical properties (6) will be described.
First, for 100 composite particles in a dried state, the number of inorganic fine particles B present on the surface of the organic core particle A is measured by the above-described SEM image observation (number before ultrasonic irradiation).
On the other hand, using the same composite particles, a composite particle dispersion is prepared by dispersing in water at a blending ratio of 1% by weight of the composite particles. Thereafter, the composite particle dispersion is irradiated with ultrasonic waves for 30 minutes under conditions of an output of 110 W and a frequency of 31 kHz. Thereafter, the composite particle dispersion is subjected to solid-liquid separation by centrifugal sedimentation, the sediment is collected, and the sediment is dried. With respect to 100 composite particles in the dried solid, the number of inorganic fine particles B present on the surface of the organic core particle A is measured by the above-described SEM image observation (number after ultrasonic irradiation).
The number change (%) before and after the ultrasonic irradiation is obtained by comparing the number before the ultrasonic irradiation and the number after the ultrasonic irradiation thus obtained.
As described above, the measurement condition for the change in the number of physical properties (6) is that the composite particle dispersion to be irradiated with ultrasonic waves with an output of 110 W and a frequency of 31 kHz is a 1% by weight aqueous dispersion of composite particles. The irradiation time is 30 minutes. The output, frequency, and irradiation time of the ultrasonic wave, for example, give the composite particles a load corresponding to stress such as shear force that may be applied when the composite particles are used as a component such as an external additive for toner. To be able to In addition, the amount of the composite particles in the 1% by weight aqueous dispersion of the composite particles is such that the composite particles in the dispersion are not excessively dense and the composite particles in the dispersion are not excessively diluted. The composite particles are set in consideration of the point that the composite particles are dispersed in the dispersion liquid and the irradiation efficiency of the ultrasonic waves is not hindered. Therefore, obtaining the change in the number according to the measurement conditions described above corresponds to a substantial durability test when, for example, the composite particles are used as a constituent component such as an external additive for toner. It becomes possible to know the degree of adhesion strength on the organic core particle A relatively accurately and in a short time.

  In addition, the number change of the physical property (6) is obtained by a durability test other than the durability test by the ultrasonic irradiation described above (for example, a durability test by stirring and shaking using a tumbler mixer described later) and the SEM image observation described above. Can be obtained by combining other methods of obtaining (for example, obtaining by microscopic observation using a TEM image). For specific composite particles other than the composite particles of the present invention, the number change obtained by a method combining a durability test other than the durability test by ultrasonic irradiation described above and a method other than the method of determining by SEM image observation described above is a physical property. Even if it is different from the numerical range of (6), the change in the number of the specific composite particles obtained by combining the durability test by the above-described ultrasonic irradiation and the above-described method of obtaining by SEM image observation is a physical property. When included in the numerical range of (6), the specific composite particles can be recognized as having physical properties (6).

The composite particles having the above physical properties (1) to (6) preferably further have a physical property (hereinafter referred to as physical property (7)) having a relative dielectric constant of 2 or more and 300 or less.
The numerical range of the ratio of the physical property (7) indicates the relative dielectric constant of the composite particle that is practically appropriate when the composite particle is used as a constituent component such as an external additive for toner. The relative dielectric constant of the composite particle is the ratio of the dielectric constant of the composite particle to the dielectric constant of vacuum. That is, when the dielectric constant of vacuum is ε ₀ and the dielectric constant of the composite particle is ε, the relative dielectric constant εr of the composite particle satisfies the relational expression of ε / ε ₀ = εr. In addition, the relative dielectric constant of the composite particles changes according to changes in the volume resistance ρv and the surface resistance ρs of the composite particles described above.
As described above, the relative dielectric constant of the physical property (7) is 2 or more and 300 or less, preferably 2 or more and 200 or less.
Here, if the relative dielectric constant is less than 2, the composite particles exhibit high insulation, which is not preferable in that the charge amount of the composite particles is reduced. When the relative dielectric constant exceeds 300, the composite particles exhibit a relatively high conductivity, which is not preferable in terms of charge leakage.
The dielectric constant ε of the composite particles necessary for obtaining the relative dielectric constant εr of the composite particles is obtained by using the above-described pellets used for measuring the volume resistance and surface resistance. For example, the dielectric constant measuring device (E4991A RF impedance / material It can be obtained by the following method using an analyzer (trade name), manufactured by Keysight Technology LLC.
Measure the dielectric constant with the above-mentioned dielectric constant measuring device by changing the compounding ratio of the composite particles and epoxy resin in the above pellets, draw a calibration curve based on the change in dielectric constant with respect to the epoxy resin ratio, and this calibration curve intersects The value of the intercept of the coordinate axis (dielectric constant when the epoxy resin ratio is 0%) is obtained as the dielectric constant ε (F / m) of the composite particles. Thereafter, the ratio of the dielectric constant ε of the composite particles to the dielectric constant ε _{0 of} vacuum (about 8.854 × 10 ⁻¹² F / m) (relative dielectric constant of the composite particles: εr = ε / ε ₀ ) is calculated.

  The relative dielectric constant of the physical property (7) can be obtained by combining pellets other than the pellets used for measuring the volume resistance and surface resistance described above and devices other than the dielectric constant measuring apparatus described above. For specific composite particles other than the composite particles of the present invention, the specific dielectric constant determined by a method of combining pellets other than the above-described pellets and devices other than the above-described devices is different from the numerical range of the physical properties (7). However, for the specific composite particles, when the relative dielectric constant obtained by combining the above-described pellets and the above-described apparatus is included in the numerical range of the physical properties (7), the specific composite particles have the physical properties (7 ).

The composite particles having the physical properties (1) to (6) described above or the composite particles having the physical properties (1) to (7) described above are further coated with the inorganic fine particles B on the surface of the organic core particles A. It is desirable to have a physical property of 5% or more and less than 68% (hereinafter referred to as physical property (8)).
As described above, the coverage of the physical property (8) is 5% or more and less than 68%, preferably 5% or more and 50% or less.
Here, if the coverage is less than 5%, the surface of the composite particle, that is, the uneven shape formed by the inorganic fine particles B on the surface of the organic core particle A is not sufficient. When used as a fluidity improver such as an external additive, the number of times that the composite particles roll to contact the organic core particles A constituting the other composite particles and the surface of the toner increases. It is not preferable in that it cannot be obtained sufficiently. Further, when the coverage exceeds 68%, the inorganic fine particles B overlap each other on the surface of the organic core particle A. Therefore, the inorganic fine particles B are not in contact with the surface of the organic core particle A and overlap the inorganic fine particles B. The adhesion strength of the fine particles B is lowered, and it is not preferable in that it easily detaches and causes fine powder.

The coverage of the physical property (8) can be obtained from the SEM image observation described above.
First, as in the case of obtaining the average particle diameter described above, SEM images for a total of 100 composite particles are obtained while changing the field of view of the SEM image. Thereafter, a rectangular region is set for the projected image of the composite particle of the obtained SEM image, and the area covered with the inorganic fine particles B on the surface of the organic core particle A is obtained within the region, and the inorganic with respect to the area of the region is determined. The coverage (%) of the fine particles B is determined.

  The coverage of the physical property (8) can be obtained by a method other than the SEM image observation described above. For specific composite particles other than the composite particles of the present invention, even if the coverage obtained by a method other than the SEM image observation described above is different from the numerical range of the physical properties (8), When the coverage obtained by the SEM image observation described above is included in the numerical range of the physical property (8), the specific composite particles can be recognized as having the physical property (8).

The composite particles having the above physical properties (1) to (6) or the composite particles having the physical properties (1) to (6) and the physical properties (7) or (8) are shown in FIG. As shown, it is desirable to further include an inorganic material layer N that covers the surface of the organic core particle A and the surface of the inorganic fine particle B.
The inorganic material layer N is formed by interacting with the organic core particle A and bonding (condensing) with a hydroxyl group (OH group) present on the surface of the inorganic fine particle B under basic conditions. As such a substance, a silane coupling agent is preferably used. Under basic conditions, the hydroxyl group (OH group) on the surface of the inorganic fine particle B and the silane coupling agent itself constitute a network structure, and silicon is contained inside. An inorganic material layer N having a structure similar to the amorphous structure of silica having (Si) is formed.
Thus, since the inorganic material layer N has a network structure that covers the surface of the organic core particle A and the surface of the inorganic fine particle B, the role of increasing the adhesion strength of the inorganic fine particle B on the organic core particle A and silicon Since it has a structure similar to the amorphous structure of silica by containing (Si), it exhibits an electrical resistance comparable to that of a film formed from an inorganic material such as silica. It plays a role of adjusting the balance of the surface resistance ρs.
As the silane coupling agent used for forming the inorganic material layer N, the formula R ¹ —Si (OR ² ) ₃ (wherein R ¹ has 1 to 6 carbon atoms containing one or both of oxygen and nitrogen). Or a hydrocarbon group having 1 to 18 carbon atoms which does not contain oxygen and nitrogen, and R ² is a monovalent hydrocarbon group having 1 to 6 carbon atoms). Among them, compounds that can form the above-described silicon-containing network structure are exemplified. Specifically, as the silane coupling agent used for forming the inorganic material layer N, 3- (trimethoxysilyl) propyl methacrylate (hereinafter referred to as MAPTMS), 3- (trimethoxysilyl) propyl acrylate, triethoxy (3-glycidyloxypropyl) silane, octadecyltriethoxysilane, allyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltriethoxy Examples thereof include, but are not limited to, silane, 3-ureidopropyltriethoxysilane, aminopropyltriethoxysilane.
Such a silane coupling agent is appropriately selected according to the type of organic material forming the organic core particle A. For example, if the organic material forming the organic core particle A is an acrylic resin or a methacrylic resin, a silane having a reactive bonding group (for example, an alkoxy group such as a methoxy group) that interacts with a functional group of the acrylic resin or the methacrylic resin A coupling agent is selected. If the organic material is a polyester resin, a silane coupling agent having a reactive bonding group (isocyanate group) that interacts with a functional group of the polyester resin is selected. If the organic material is an epoxy resin, a silane coupling agent having a reactive bonding group (epoxy group) that interacts with a functional group of the epoxy resin is selected. If the organic material is a urethane resin, a silane coupling agent having a reactive bonding group (urethane group) that interacts with a functional group of the urethane resin is selected. Here, the interaction differs depending on the type of the organic material, but forms a network structure based on the affinity between the functional group of the organic material and the reactive binding group of the silane coupling agent, and Sufficient intermolecular force to maintain.
The basic condition is pH 8 or more and pH 13 or less, preferably pH 8 or more and pH 12 or less.
Examples of basic substances used to obtain basic conditions include, but are not limited to, ammonia, sodium hydroxide, potassium hydroxide, and the like.

The composite particles according to the first embodiment having the above-mentioned physical properties have the positively charged inorganic fine particles B present on the negatively charged organic core particles A due to heteroaggregation, and both particles are electrostatically attached. By using the inorganic material layer N formed by the action of the silane coupling agent on the surface of the particle adhering body obtained by combining the inorganic fine particles B with the surface of the organic core particles A, The surface of the core particle A and the surface of the inorganic fine particle B are coated and the inorganic fine particle B is immobilized on the surface of the organic core particle A. Examples corresponding to such composite particles are Examples 1-1 to 1-17 described later.
Further, at the time of compositing as described above, the organic fine particles charged negatively by the hetero-aggregation can be present on the surface of the organic core particles A that are positively charged as a whole, and can be electrostatically attached. . And, by the inorganic material layer N formed by the action of the above-mentioned silane coupling agent on the surface of the particle adhesion body obtained by combining and combining the inorganic fine particles B and the organic fine particles on the surface of the organic core particles A, The surfaces of the organic core particles A, the inorganic fine particles B, and the organic fine particles can be coated to form composite particles that are present in the inorganic fine particles B and the organic fine particles on the surface of the organic core particles A. That is, the composite particles are formed by combining the organic core particles A, the inorganic fine particles B and the organic fine particles (not shown) existing on the surface of the organic core particles A. Examples corresponding to such composite particles are Examples 3-1 to 3-6 described later.

B. Manufacturing method of composite particle This manufacturing method of a composite particle is a manufacturing method of a composite particle provided with the organic core particle A and the inorganic fine particle B, and includes a particle adhering body formation process and a composite particle formation process.
This manufacturing method is an example of a manufacturing method capable of manufacturing the composite particles having the physical properties described in A above.
Hereinafter, it demonstrates for every process.

1. Particle Adherent Forming Step In this particle adhering body forming step, the inorganic fine particles B are formed on the surface of the organic core particles A from a dispersion containing the organic core particles A and the inorganic fine particles B (hereinafter sometimes referred to as organic inorganic particle dispersion). This is a step of forming a particle adhering body to which is attached. This particle adhesion body is an intermediate product formed before producing composite particles obtained by the subsequent composite particle forming step.
First, prior to the particle adhering body forming step, as a preliminary preparation, an organic-inorganic particle dispersion is prepared as follows.

  In order to prepare the organic / inorganic particle dispersion, the organic core particles A and the inorganic fine particles B are individually formed as a preliminary preparation.

(A) Formation of Organic Core Particle A As described below, the organic core particle A comprises (i) preparation of raw materials for the organic core particle A, (ii) synthesis of the organic core particle A, and (iii) reaction residue. It is formed through each step of removal.

(I) Preparation of raw material of organic core particle A As raw materials, a starting material, a composite assistant, a reaction initiator, and a particle size control agent of the organic material forming the organic core particle A are prepared.
Examples of the starting material for the organic material include monomers and oligomers of the organic material described in A above. If the organic material is an acrylic resin material, the starting material may be an alkoxy group such as methyl methacrylate (MMA), isobornyl (meth) acrylate, benzyl (meth) acrylate, hydroxyethyl (meth) acrylate, butyl (meth) acrylate, etc. Monomers, oligomers, and the like having, are not limited to these.
Examples of the alkoxy group in the starting material include, but are not limited to, a methyl group, an ethyl group, and a propyl group.
If the organic material is an acrylic resin material, the composite aids include 3- (trimethoxysilyl) propyl methacrylate (hereinafter referred to as MAPTMS), 3- (trimethoxysilyl) propyl acrylate, 3- (acrylic acid 3- ( Triethoxysilyl) propyl, allyltrimethoxysilane, allyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and other monomers having an alkoxy group, oligomers, and the like can be mentioned, but the invention is not limited thereto.
Examples of the alkoxy group in the composite aid include, but are not limited to, a methyl group, an ethyl group, and a propyl group.
If the organic material is an acrylic resin material, examples of the reaction initiator include potassium persulfate (hereinafter referred to as KPS), sodium persulfate, and azobisisobutyronitrile, but are not limited thereto. .
Examples of the particle size control agent include, but are not limited to, sodium p-styrenesulfonate (hereinafter referred to as NaSS) and ammonium p-styrenesulfonate.

(Ii) Synthesis of Organic Core Particle A Organic core particle A is synthesized using the prepared starting material and the like.
For example, after adding a predetermined amount of water to a reaction vessel equipped with a cooler, a thermometer, and a nitrogen introduction tube, the atmosphere in the reaction vessel is replaced with a nitrogen gas atmosphere to remove oxygen. Then, after adding MMA, NaSS and MAPTMS and stirring, a predetermined amount of KPS is added to the mixed solution, MMA and MAPTMS are polymerized in the mixed solution, MMA is crosslinked by MAPTMS, and the particle size is controlled. Polymethyl methacrylate (hereinafter referred to as PMMA) particles are synthesized, and a dispersion in which the PMMA particles are dispersed is obtained.
The blending amounts of water, MMA, MAPTMS, and KPS into the reaction system are determined in consideration of the mechanical strength required for the organic core particles A, and the blending amount of NaSS is the particle size required for the organic core particles A. It is decided in consideration.
The polymerization reaction temperature is 0 ° C. or higher and 150 ° C. or lower, preferably 25 ° C. or higher and 80 ° C. or lower. The polymerization reaction time is 15 minutes to 24 hours, preferably 1 hour to 16 hours.

(Iii) Removal of reaction residue in dispersion The PMMA particles in the dispersion are subjected to a series of operations such as solid-liquid separation by centrifugal sedimentation, decantation of the supernatant, and addition of a predetermined amount of distilled water, for example. Finally, a predetermined amount of water is added to obtain an aqueous dispersion of PMMA particles (organic core particles A).

(B) Formation of inorganic fine particles B The inorganic fine particles B are subjected to the steps of (i) preparation of raw materials for the inorganic fine particles B, (ii) preparation of components, (iii) synthesis of the inorganic fine particles B and removal of reaction residues. ,It is formed.

(I) Preparation of raw materials for inorganic fine particles B As raw materials, a starting material of inorganic material for forming inorganic fine particles B, an organic solvent, and a catalyst are prepared.
As a starting material of the inorganic material, a compound containing an inorganic substance (for example, silicon, titanium, zirconium, aluminum) in the inorganic material described in A above can be given. If the inorganic material is silica, examples of the starting material include a formula: R ² R ³ Si (OR ¹ ) ₂ , a formula: R ² Si (OR ¹ ) ₃ , a formula: Si (OR ¹ ) ₄ (wherein Each R ¹ in each formula is a monovalent hydrocarbon group having 1 to 6 carbon atoms, and R ² and R ³ are both hydrocarbon groups having 1 to 20 carbon atoms) and its silane compound Examples include hydrolysis condensates.
Examples of the silane compound include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, tetraethoxysilane, dimethyldiethoxysilane, ethyltrimethoxysilane, isobutyltrimethoxysilane, and propylmethyl. Examples include, but are not limited to, silane compounds (monomer components) such as diethoxysilane, propyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane. Examples of the hydrolysis condensate of the above silane compound include hydrolysis condensates (such as dimers and oligomers) obtained by condensing hydrolyzable groups (methoxy group, ethoxy group, etc.) in the above silane compound. However, it is not limited to these.

  Examples of the organic solvent include, but are not limited to, protic solvents and aprotic solvents. Examples of protic solvents include ethanol, 1-propanol, and 2-propanol. Examples of the aprotic solvent include acetonitrile, acetone, methyl isobutyl ketone, methyl ethyl ketone, and toluene.

  Examples of the catalyst include, but are not limited to, basic compounds such as ammonia, dimethylamine, diethylamine, trimethylamine, sodium hydroxide, and potassium hydroxide.

(Ii) Preparation of Containing Component A component containing a silane compound or hydrolysis condensate (hereinafter referred to as an organosilicon compound) as a starting material (hereinafter referred to as a silicon-containing component) and a component containing a catalyst (hereinafter referred to as a catalyst-containing component). ) Individually.
First, a predetermined amount of an organosilicon compound and an organic solvent are mixed to prepare a silicon-containing component.
On the other hand, a catalyst-containing component is prepared by mixing a predetermined amount of a basic compound and a solvent.
Each compounding amount of the organosilicon compound and the organic solvent in the silicon-containing component is determined in consideration of mechanical strength required for the inorganic fine particles B, and each compounding amount of the basic compound and the solvent in the catalyst-containing component is The amount is determined in consideration of the compounding amount of the silicon-containing component.

(Iii) Synthesis of inorganic fine particles B and removal of reaction residue First, the liquid temperature of the prepared silicon-containing component is controlled and stirred.
On the other hand, the liquid temperature of the prepared catalyst-containing component is controlled to be the liquid temperature of the silicon-containing component, and after the liquid temperature is reached, the catalyst-containing component is added to the silicon-containing component all at once and mixed.
Then, the liquid mixture containing both components is stirred and concentrated by heating until the liquid volume becomes half. Thereafter, for example, a series of operations of solid-liquid separation by centrifugal sedimentation, decantation of the supernatant, and addition of a predetermined amount of distilled water are repeated, and finally, a predetermined amount of water is added to remove the reaction residue. A dispersion in which the inorganic fine particles B) are dispersed is obtained.
Each compounding amount of the silicon-containing component and the catalyst-containing component in the reaction system is determined in consideration of the mechanical strength required for the inorganic fine particles B.
The reaction temperature is 0 ° C. or higher and 100 ° C. or lower, preferably 15 ° C. or higher and 80 ° C. or lower. The reaction time is 1 hour or more and 24 hours or less, preferably 2 hours or more and 12 hours or less.

<Formation of particle adhesion>
The particle adhering is performed using the organic core particles A synthesized as described above and the inorganic fine particles B synthesized as described above, (i) a step of preparing an organic-inorganic particle dispersion, (ii) organic-inorganic particles It is formed through a stirring step after preparation of the dispersion, (iii) a pH adjustment step of the organic-inorganic particle dispersion, and (iv) an adhesion step.

(I) Preparation Step of Organic Inorganic Particle Dispersion First, a dispersion containing organic core particles A (eg, PMMA core particles) and a dispersion containing inorganic fine particles B (eg, silica fine particles) are stirred in a reaction vessel. While mixing, an organic-inorganic particle dispersion is obtained.
The blending ratio of the organic core particles A and the inorganic fine particles B in the organic inorganic particle dispersion liquid and the blending ratio of the two particles are based on the size relationship between the average particle diameters of the organic core particles A and the inorganic fine particles B. It is determined in consideration of the assumed number of inorganic fine particles B to be adhered to the surface of the material.
The liquid temperature during the preparation of the organic / inorganic particle dispersion is from 0 ° C. to 100 ° C., and preferably from 15 ° C. to 80 ° C.

(Ii) Stirring step after preparation of organic-inorganic particle dispersion The organic-inorganic particle dispersion is then stirred for a predetermined time at a predetermined liquid temperature, if necessary.
In this stirring step, the organic core particles A and the inorganic fine particles B are sufficiently dispersed in the organic-inorganic particle dispersion in the neutral region, giving the opportunity for contact between the two particles, and a large amount of inorganic on the surface of the organic core particles A. Presence of fine particles B. At this stage, the surfaces of the organic core particles A and the inorganic fine particles B are both negatively charged, so it is considered that both particles are not electrostatically coupled.
The liquid temperature of the dispersion in the stirring step is 0 ° C. or higher and 100 ° C. or lower, preferably 15 ° C. or higher and 80 ° C. or lower, and the stirring time is 0 hour or longer and 24 hours or shorter, preferably 15 minutes or longer. 15 hours or less.

(Iii) pH adjustment step of the organic / inorganic particle dispersion liquid Subsequently, the inorganic material that forms the inorganic fine particles B in the dispersion liquid while measuring the pH of the organic / inorganic particle dispersion liquid whose liquid temperature and stirring speed are maintained. The acidic solution is continuously added dropwise over time until the electric point (silica, pH 2.0) is reached, and when the isoelectric point (silica, pH 2.0) is reached, the dropping of the acidic solution is stopped.
In this pH adjustment step, the surface of the inorganic fine particles B in the dispersion is acidified in the vicinity of pH 2 from the neutral region by lowering the dispersion from the neutral region to the isoelectric point (pH 2.0 in the case of silica). The region is negatively charged, but changes to a positive charge below the isoelectric point. On the other hand, the surface of the organic core particles A in the dispersion continues to be negatively charged from the neutral region to below the isoelectric point of the inorganic material. Therefore, if the pH of the dispersion is at the isoelectric point, the organic core particles A and the inorganic fine particles B are charged with opposite charges, so that they tend to aggregate with each other, and both particles can be attached electrostatically. .
Examples of the acidic solution include hydrochloric acid, sulfuric acid, nitric acid, acetic acid and the like, but are not limited thereto.

(Iv) Adhesion step Thereafter, the organic inorganic particle dispersion liquid is heated to a predetermined liquid temperature, and then stirred at a predetermined liquid temperature for a predetermined time, so that the surface of the organic core particle A (for example, PMMA core particle) is inorganic. A particle adhering body to which fine particles B (for example, silica fine particles) are adhered is formed.
In this adhesion step, the inorganic fine particles B are present on the organic core particles A by heteroaggregation, and the inorganic fine particles B charged to the positive charge in the pH adjustment step described above on the surface of the organic core particles A charged to the negative charge. Is attached electrostatically to form a particle adhering body.
The liquid temperature is 0 ° C. or higher and 100 ° C. or lower, preferably 15 ° C. or higher and 80 ° C. or lower.
The stirring time is from 0 hour to 24 hours, preferably from 5 minutes to 12 hours.

2. Composite particle forming step This composite particle forming step interacts with the reactive binding group present on the surface of the organic core particle A in the dispersion in which the particle adhering body is formed, and under basic conditions. The surface of the organic core particle A is formed by the inorganic material layer N obtained by adding a silane coupling agent and a basic substance that are bonded to the hydroxyl group (OH group) present on the surface of the inorganic fine particle B and causing the silane coupling agent to act. And a step of forming composite particles in which the surface of the inorganic fine particles B is coated and the inorganic fine particles B are immobilized on the surface of the organic core particles A. Examples of the reactive bonding group herein include, but are not limited to, alkoxy groups such as a hydroxyl group, a carboxyl group, a urethane group, and a methoxy group.
In such a composite particle forming step, electrostatic adhesion of the inorganic fine particles B present on the organic core particles A by heteroaggregation in the particle adhering member forming step to the organic core particles A is performed by using a silane coupling agent. The inorganic material layer N formed by the action immobilizes the inorganic fine particles B on the organic core particles A, and improves the adhesion strength of the inorganic fine particles B on the organic core particles A.

As the silane coupling agent used for forming the inorganic material layer N, the formula R ¹ —Si (OR ² ) ₃ (wherein R ¹ has 1 to 6 carbon atoms containing one or both of oxygen and nitrogen). Or a hydrocarbon group having 1 to 18 carbon atoms which does not contain oxygen and nitrogen, and R ² is a monovalent hydrocarbon group having 1 to 6 carbon atoms). Among them, compounds that can form a silicon-containing network structure are included. Specifically, as the silane coupling agent used for forming the inorganic material layer N, 3- (trimethoxysilyl) propyl methacrylate (MAPTMS), 3- (trimethoxysilyl) propyl acrylate, vinyltriethoxysilane , Vinyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltriethoxysilane, octadecyltriethoxysilane, 3-ureidopropyltriethoxysilane, aminopropyltriethoxysilane, triethoxy (3-glycidyloxypropyl) silane , 3-isocyanatopropyltriethoxysilane and the like, but are not limited thereto.
Such a silane coupling agent is appropriately selected according to the type of organic material forming the organic core particle A. For example, if the organic material forming the organic core particle A is an acrylic resin or a methacrylic resin, a silane having a reactive bonding group (for example, an alkoxy group such as a methoxy group) that interacts with a functional group of the acrylic resin or the methacrylic resin A coupling agent is selected. If the organic material is a polyester resin, a silane coupling agent having a reactive bonding group (isocyanate group) that interacts with a functional group of the polyester resin is selected. If the organic material is an epoxy resin, a silane coupling agent having a reactive bonding group (epoxy group) that interacts with a functional group of the epoxy resin is selected. If the organic material is a urethane resin, a silane coupling agent having a reactive bonding group (isocyanate group) that interacts with a functional group of the urethane resin is selected.
The basic condition is pH 8 or more and pH 13 or less, preferably pH 8 or more and pH 10 or less.
Examples of basic substances used to obtain basic conditions include, but are not limited to, ammonia, sodium hydroxide, potassium hydroxide, and the like.

  In the above-mentioned particle adhering body formation step in the case where the composite particles are formed by combining organic core particles, inorganic fine particles and organic fine particles present on the surface of the organic core particles, first, the organic core particles By adjusting the pH of the dispersion containing inorganic fine particles to the isoelectric point (for example, pH 2.0) of the inorganic fine particle forming material, the inorganic fine particles are present on the organic core particles by heteroaggregation, and the organic core particles The inorganic fine particles are electrostatically attached to the surface, and then a dispersion containing organic fine particles is added to the dispersion. A particle adhering body in which the fine particles are further electrostatically adhered is formed. By performing the subsequent composite particle forming step in the same manner as the above-described composite particle forming step, composite particles in which inorganic fine particles and organic fine particles are immobilized on the surface of the organic core particles can be obtained.

3. Particle Recovery Step This particle recovery step can be performed as a step of recovering the composite particles from the composite particle dispersion obtained in the above-described composite particle formation step.
In this step, only the composite particles are separated and recovered from the composite particle dispersion. The recovery method is not particularly limited as long as it does not deform the surface of the composite particles in the dispersion and does not damage the composite particles. For example, heating concentration using an evaporator, centrifugation Examples thereof include solid-liquid separation using a settling machine and freeze-drying.
Since the composite particles recovered by the particle recovery process can have the physical properties described in A above, the adhesion strength of the inorganic fine particles B to the organic core particles A is high, and the good charge amount and high fluidity are obtained. It can be secured.

4). Particle Hydrophobization Process This particle hydrophobization process is a process of reacting a hydroxyl group (OH group) remaining on a part of the composite particle surface with a hydrophobizing agent to introduce a hydrophobic group into the composite particle surface, thereby This is a process of hydrophobizing. This particle hydrophobizing step is optionally performed according to the use for which high hydrophobicity is required, such as when composite particles are used as a constituent component such as an external additive for toner.
As the composite particles to be hydrophobized in this particle hydrophobization step, the composite particles recovered in the above-described particle recovery step or the sol state dispersed in the dispersion liquid of the composite particles formed in the above-described composite particle formation step Any of these composite particles may be used. In the former case, composite particles are produced in the order of the composite particle formation step, the particle recovery step, and the particle hydrophobization step. In the latter case, composite particles are produced in the order of the composite particle formation step, the particle hydrophobization step, and the particle recovery step.

As hydrophobizing agents, hexamethyldisilazane (HMDS), 1,3-diphenyltetramethyldisilazane, 1,3-bis (3,3,3-trifluoropropyl) -1,1,3,3-tetramethyl Silazane compounds such as disilazane, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, methyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, isobutyltrimethoxysilane, octyltriethoxysilane, Silane compounds such as decyltriethoxysilane, trimethylmethoxysilane, and triethylmethoxysilane can be exemplified, but are not limited thereto.
Examples of the solvent for the silazane compound or silane compound that function as a hydrophobizing agent include protic solvents such as water, ethanol, and methanol, or aprotic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. Can do.

  Since the composite particles whose surface has been hydrophobized by the above-described particle hydrophobization process have both the physical properties and the hydrophobicity described in A above, the adhesion strength of the inorganic fine particles B to the organic core particles A is high, and good charging is achieved. The amount and high fluidity can be secured, and a high degree of hydrophobicity can be maintained.

C. Toner External Additive The toner external additive includes the composite particles described in A above.
The composite particles as the toner external additive have high adhesion strength of the inorganic fine particles B to the organic core particles A, and the inorganic fine particles B are difficult to be detached from the organic core particles A. Therefore, the toner external additives containing the composite particles Even when subjected to various stresses such as shearing force during use, it adheres firmly to the toner particles over a long period of time. Further, the composite particles as the toner external additive can ensure a good charge amount and high fluidity. Toner with external addition of composite particles as an external additive for toner has high deterioration resistance and can be used while maintaining high transfer efficiency over a long period of time. The resulting image degradation can be suppressed and stable image quality can be provided.
Further, when the composite particles as the external additive for the toner have a relatively small average particle size in the numerical range of the average particle size of the above physical property (4), high fluidity can be imparted to the toner particles. .
Furthermore, when the composite particles as the external additive for the toner have a relatively large average particle diameter in the numerical range of the average particle diameter of the above physical property (4), the spacer effect can be sufficiently exhibited.

According to the composite particle of Embodiment 1, in the composite particle including the organic core particle A and the inorganic fine particle B, the main component of the organic core particle A is an organic material, and the inorganic fine particle B is on the organic core particle A. And the main component of the inorganic fine particles B is an inorganic material, the average particle diameter of the organic core particles A is 80 nm or more and 300 nm or less, and the variation coefficient of the average particle diameter of the organic core particles A is 2% or more and 10% or less. The average particle diameter of the inorganic fine particles is 5 nm or more and 30 nm or less, and the ratio of the average particle diameter of the inorganic fine particles B to the average particle diameter of the organic core particles A is 0.016 or more and 0.25 or less; The average particle diameter of the composite particles is 90 nm or more and 350 nm or less, the ratio ρr of the volume resistance ρv and the surface resistance ρs of the composite particles is 0.7 or more and 1.4 or less, and is dispersed in water so that the composite particles are 1 wt%. Let The number change of the inorganic fine particles B present on the organic core particles A before and after the composite particle dispersion is irradiated with ultrasonic waves for 30 minutes under the conditions of an output of 110 W and a frequency of 31 kHz is 0.5% or more and 5% or less. .
The composite particles having the above physical properties have the following effects.
(I) In the composite particles, inorganic fine particles B exist in the organic core particles A, and the change in the number of inorganic fine particles B present in the organic core particles A before and after ultrasonic irradiation under a predetermined condition is extremely small. Compared to conventional composite particles in which the fine particles B are simply attached to the organic core particles A, the adhesion strength of the inorganic fine particles B on the organic core particles A is high. Since the adhesion strength of the inorganic fine particles B onto the organic core particles A is high, the inorganic fine particles B are not easily detached from the cored particles A even when subjected to various stresses such as shearing force.
(Ii) Since the composite particles have a volume resistance ρv and a surface resistance ρs in a predetermined numerical range, a favorable charge amount can be secured as an initial characteristic. This good charge amount can be maintained for a long period of time because the adhesion strength of the inorganic fine particles B onto the organic core particles A is high and the inorganic fine particles B are not easily detached from the organic core particles A.
(Iii) Since the organic core particles A and the inorganic fine particles B have a ratio of the average particle diameter and the average particle diameter in a predetermined numerical range and have a coverage in a predetermined numerical range, for example, an external additive for toner When the toner is used as a component of the toner, the toner and the composite particles always come into contact with the toner and the fine particles present on the composite particles, so that high fluidity can be secured as an initial characteristic without lowering rolling properties. . The composite particles having high fluidity can be favorably applied as a component such as an external additive for toner. The high fluidity can be maintained over a long period of time because the adhesion strength of the inorganic fine particles B onto the organic core particles A is high and the inorganic fine particles B are not easily detached from the organic core particles A.
Therefore, the composite particles of Embodiment 1 have high adhesion strength of the inorganic fine particles B onto the organic core particles A, and can ensure a good charge amount and high fluidity.

According to the method for producing composite particles of the first embodiment, in the method for producing composite particles comprising organic core particles A and inorganic fine particles B, the organic core particles A mainly composed of an organic material and the inorganic material as a major component. A particle adhering body forming step of forming a particle adhering body in which the inorganic fine particle B adheres to the surface of the organic core particle A from the dispersion liquid containing the inorganic fine particle B, and an organic core particle in the dispersion liquid in which the particle adhering body is formed. Silane coupling agent and basic substance that interacts with the reactive binding group present on the surface of A and binds (condenses) with the hydroxyl group (OH group) present on the surface of the inorganic fine particle B under basic conditions And a composite particle forming step of forming composite particles in which the inorganic fine particles B are immobilized on the surface of the organic core particles A.
In the particle adhering body forming step, the inorganic fine particle B is present on the organic core particle A by hetero-aggregation, and the particle adhering body in which the inorganic fine particle B is electrostatically adhered to the surface of the organic core particle A is formed, and the composite In the particle forming step, composite particles in which the inorganic fine particles B are immobilized on the surface of the organic core particles A can be formed by the inorganic material layer N formed by the action of the silane coupling agent. This composite particle can have each of the physical properties described above.
Therefore, according to the method for producing composite particles of Embodiment 1, it is possible to produce composite particles that have high adhesion strength of the inorganic fine particles B onto the organic core particles A, and that can ensure a good charge amount and high fluidity. it can.

  According to the external additive for toner of Embodiment 1, the composite particles described above are included. Therefore, the external additive for toner has high adhesion strength of the inorganic fine particles B onto the organic core particles A, and can secure a good charge amount and high fluidity. In addition, the adhesion between the toner external additive and the toner particles can be maintained, the transfer efficiency can be maintained at a high level, and the toner external additive is not easily separated from the toner particles, thereby suppressing image defects caused by contamination of the member. In addition, stable image quality can be provided.

Embodiment 2. FIG.
A. Composite particles Unlike the composite particles according to the first embodiment, the composite particles include core particles mainly composed of an inorganic material (hereinafter, the core particles may be referred to as inorganic core particles), and the inorganic particles on the inorganic core particles. And fine particles mainly containing an organic material (hereinafter, the fine particles may be referred to as organic fine particles). The composite particles also have the following physical properties (1) to (6) as in the first embodiment.
Physical property (1): The average particle diameter of the inorganic core particles is 80 nm or more and 300 nm or less.
Physical property (2): The variation coefficient of the average particle diameter of the inorganic core particles is 2% or more and 10% or less.
Physical property (3): The average particle diameter of the organic fine particles is 5 nm or more and 30 nm or less, and the ratio of the average particle diameter of the organic fine particles to the average particle diameter of the inorganic core particles (hereinafter, the average particle diameter of the organic fine particles / inorganic core particles The average particle diameter is 0.016 or more and 0.25 or less.
Physical property (4): The average particle diameter of the composite particles is 90 nm or more and 350 nm or less.
Physical property (5): Ratio ρr of volume resistance ρv and surface resistance ρs of the composite particles is 0.7 or more and 1.4 or less.
Physical property (6): Present in inorganic core particles before and after irradiating ultrasonic waves for 30 minutes under conditions of an output of 110 W and a frequency of 31 kHz on a composite particle dispersion in which the composite particles are dispersed in water so that the composite particles are 1% by weight. The change in the number of organic fine particles is 0.5% or more and 5% or less.

The core particles and fine particles constituting the composite particles have the following common points and differences from the core particles and fine particles constituting the composite particles according to Embodiment 1.
<Inorganic core particles>
The inorganic core particles are the same as the inorganic fine particles B in the first embodiment in that the main component is the same inorganic material as that described in A of the first embodiment.
However, since the inorganic core particle is a core particle, the inorganic fine particle according to the first embodiment has an average particle diameter satisfying only the physical property (3) in that it has an average particle diameter satisfying the physical properties (1) to (3). Different from B.
<Organic fine particles>
The organic fine particles are common to the organic core particles A in the first embodiment in that the organic material similar to the organic material described in A of the first embodiment is the main component.
However, since the organic fine particles are fine particles, the organic core particles A in the first embodiment having an average particle size satisfying the physical properties (1) to (3) in that they have an average particle size satisfying only the physical property (3). Is different.

  In the composite particles, the volume resistance ρv depends on the resistance of the inorganic material forming the inorganic core particles and the organic material forming the fine particles B, and the surface resistance ρs depends on the electrical resistance specific to the surface of the composite particles. . Since the electrical resistance of the inorganic material forming the inorganic core particles is lower than that of the organic material forming the organic fine particles, the composite particles having the above-described configuration have a low volume resistance ρv and a high surface resistance ρs. In general, the electric charge charged on the particle surface enters the inside of the particle or travels through the particle surface, and from the other surface of the particle (for example, the contact surface with the toner particle to which the composite particle is externally added) to other particles. It is thought that it will shift to. However, in composite particles comprising inorganic core particles and organic fine particles, the charge charged on the surface is limited to transfer to other particles (for example, toner particles). It is estimated that it will gradually accumulate. For this reason, it is important that the relationship between the volume resistance ρv and the surface resistance ρs is in an appropriate numerical range of the physical property (5).

The composite particles having the above physical properties (1) to (6) preferably have the physical property (7) that the relative dielectric constant is 2 or more and 300 or less, similarly to the composite particles according to the first embodiment. .
The composite particles having the above physical properties (1) to (6) or the composite particles having the physical properties (1) to (6) and the physical property (7) are the same as the composite particles according to the first embodiment. Furthermore, it is desirable to have the physical property (8) that the coverage of the organic fine particles on the surface of the inorganic core particles is 5% or more and less than 68%.

The composite particles having the above physical properties (1) to (6), or the composite particles having both the physical properties (1) to (6) and the physical properties (7) or (8) are according to the first embodiment. As with the composite particles, it is desirable to further include an inorganic material layer N that covers the surfaces of the inorganic core particles and the organic fine particles.
The inorganic material layer N is formed by the action of a silane coupling agent that interacts with organic fine particles and bonds (condenses) with a hydroxyl group (OH group) present on the surface of the inorganic core particle under basic conditions. . Due to the action of this silane coupling agent, under basic conditions, the hydroxyl group (OH group) on the surface of the inorganic core particles and the silane coupling agent itself constitute a network structure, with silicon (Si) inside, An inorganic material layer N having a structure similar to the amorphous structure of silica is formed.
Thus, since the inorganic material layer N has a network structure that covers the surface of the inorganic core particles and the surface of the organic fine particles, the role of increasing the adhesion strength of the organic fine particles on the inorganic core particles and silicon (Si) Since it has a structure similar to the amorphous structure of silica by including it, it exhibits the same electrical resistance as a film formed from an inorganic material such as silica, so that the volume resistance ρv and surface resistance ρs of the composite particles And the role of adjusting the balance.

In the composite particles according to the second embodiment having the above-mentioned physical properties, organic particles finely charged negatively exist on the inorganic core particles charged positively by heteroaggregation, and both particles are electrostatically attached. Then, the surface of the inorganic core particle is formed by the inorganic material layer N formed by the action of the above-mentioned silane coupling agent on the surface of the particle adhering body obtained by combining the organic fine particles with the surface of the inorganic core particle. In addition, the surface of the organic fine particles is coated and the organic fine particles are immobilized on the surface of the inorganic core particles. Examples corresponding to such composite particles are Examples 2-1 to 2-8 described later.
Further, at the time of compositing, inorganic fine particles charged positively by heteroaggregation can be present on the surface of the composite particles charged negatively as a whole, and can be electrostatically attached. Then, the inorganic core is formed on the surface of the particle adhering body obtained by combining organic fine particles and inorganic fine particles on the surface of the inorganic core particles to form the inorganic core by the inorganic material layer N formed by the action of the silane coupling agent. It is possible to form composite particles in which the surfaces of the particles, organic fine particles, and inorganic fine particles are coated to fix the organic fine particles and the inorganic fine particles on the surfaces of the inorganic core particles. That is, this composite particle is formed by combining inorganic core particles, organic fine particles and inorganic fine particles immobilized on the surface of the inorganic core particles. Examples corresponding to such composite particles are Examples 4-1 to 4-6 described later.

B. Method for producing composite particle This method for producing a composite particle is a method for producing a composite particle comprising inorganic core particles and organic fine particles. In the method for producing composite particles, inorganic core particles mainly composed of an inorganic material and organic fine particles mainly composed of an organic material are used. Forming a particle adhering body in which organic fine particles adhere to the surface of the inorganic core particles from a dispersion liquid containing a reactive bond existing on the surface of the organic fine particles in the dispersion liquid in which the particle adhering bodies are formed A silane coupling agent that interacts with a group and binds (condenses) with a hydroxyl group (OH group) present on the surface of the inorganic core particle under a basic condition and a basic substance are added. And a composite particle forming step of forming composite particles in which organic fine particles are fixed on the surface.
In the particle adhering body forming step, organic fine particles are present on the inorganic core particles by hetero-aggregation, and a particle adhering body in which the organic fine particles are electrostatically attached to the surface of the inorganic core particles is formed. The composite material in which organic fine particles are immobilized on the surface of the inorganic core particles is formed by the inorganic material layer N formed by the action of the silane coupling agent.
This manufacturing method is an example of a manufacturing method capable of manufacturing the composite particles having the physical properties described in A above.
The particle adhering body formation step, the preparation in advance, and the composite particle formation step are the production of composite particles according to Embodiment 1 except that the organic core particles A are replaced with inorganic core particles and the inorganic fine particles B are replaced with organic fine particles. It can be performed in the same manner as the particle adhering body forming step, its preparatory preparation, and the composite particle forming step in the method.

  Further, in the particle adhering body forming step in the case where the composite particle is formed by combining the inorganic core particle, the organic fine particle and the inorganic fine particle existing on the surface of the inorganic core particle, first, the inorganic core particle and the organic By adjusting the pH of the dispersion containing fine particles to the isoelectric point of the inorganic core particle forming material (for example, pH 2.0), the organic fine particles are present on the inorganic core particles by heteroaggregation, and the surface of the inorganic core particles The organic fine particles are electrostatically attached to the surface, and then the dispersion containing inorganic fine particles is added to the dispersion, whereby the inorganic fine particles are adhered to the surface of the inorganic core particles electrostatically attached to the surface. To form a particle adhering body on which the particles are further electrostatically attached. The subsequent composite particle forming step is performed in the same manner as the composite particle forming step in the composite particle manufacturing method according to Embodiment 1 except that the organic core particles A are replaced with inorganic core particles and the inorganic fine particles B are replaced with organic fine particles. Thus, composite particles in which organic fine particles and inorganic fine particles are immobilized on the surface of the inorganic core particles can be obtained.

C. Toner External Additive The toner external additive includes the composite particles described in A above.
Composite particles as external additives for toner have high adhesion strength of organic fine particles to inorganic core particles, and organic fine particles are difficult to be detached from inorganic core particles. Even when subjected to various stresses such as shearing force, it adheres firmly to the toner particles over a long period of time. Further, the composite particles as the toner external additive can ensure a good charge amount and high fluidity. Toner with external addition of composite particles as an external additive for toner has high deterioration resistance and can be used while maintaining high transfer efficiency over a long period of time. The resulting image degradation can be suppressed and stable image quality can be provided.
Further, when the composite particles as the external additive for the toner have a relatively small average particle size in the numerical range of the average particle size of the above physical property (4), high fluidity can be imparted to the toner particles. .
Furthermore, when the composite particles as the external additive for the toner have a relatively large average particle diameter in the numerical range of the average particle diameter of the above physical property (4), the spacer effect can be sufficiently exhibited.

According to the composite particle of the second embodiment, in the composite particle including the inorganic core particle and the organic fine particle, the main component of the inorganic core particle is an inorganic material, and the organic fine particle exists on the inorganic core particle, and is organic The main component of the fine particles is an organic material, the average particle diameter of the inorganic core particles is from 80 nm to 300 nm, the variation coefficient of the average particle diameter of the inorganic core particles is from 2% to 10%, and the average particle of the organic fine particles The diameter is 5 nm or more and 30 nm or less, the ratio of the average particle diameter of the organic fine particles to the average particle diameter of the inorganic core particles is 0.016 or more and 0.25 or less, and the average particle diameter of the composite particles is 90 nm or more and 350 nm or less. A composite particle dispersion in which the volume ratio ρv of the composite particles and the ratio ρr of the surface resistance ρs is 0.7 or more and 1.4 or less, and is dispersed in water so that the composite particles are 1% by weight, Power 110W, at a frequency of 31 kHz, before and after applying ultrasonic waves for 30 minutes, the number changes of the organic fine particles present in the inorganic core particle is 5% or less than 0.5%.
The composite particles having the above physical properties have the following effects.
(I) In the composite particles, the organic fine particles are immobilized on the inorganic core particles, and the change in the number of organic fine particles present on the inorganic core particles before and after ultrasonic irradiation under a predetermined condition is extremely small. Compared to conventional composite particles simply attached on the inorganic core particles, the adhesion strength of the organic fine particles on the inorganic core particles is high. Since the adhesion strength of the organic fine particles on the inorganic core particles is high, the organic fine particles are not easily detached from the inorganic core particles even when subjected to various stresses such as shearing force.
(Ii) Since the composite particles have a volume resistance ρv and a surface resistance ρs in a predetermined numerical range, a favorable charge amount can be secured as an initial characteristic. This good charge amount can be maintained for a long period of time because the adhesion strength of the organic fine particles onto the inorganic core particles is high and the organic fine particles are not easily detached from the inorganic core particles.
(Iii) Since the inorganic core particles and the organic fine particles have an average particle diameter in a predetermined numerical range, a ratio of the average particle diameter, and a coverage in a predetermined numerical range, for example, a configuration of an external additive for toner, etc. When used as a component, the toner and the composite particles always come into contact with the toner and the fine particles present on the composite particles, so that high fluidity can be secured as an initial characteristic without lowering rolling properties. The composite particles having high fluidity can be favorably applied as a component such as an external additive for toner. High fluidity can be maintained for a long period of time because the adhesion strength of the organic fine particles onto the inorganic core particles is high and the organic fine particles are not easily detached from the inorganic core particles.
Therefore, the composite particles of Embodiment 2 have high adhesion strength of the organic fine particles onto the inorganic core particles, and can secure a good charge amount and high fluidity.

According to the method for producing composite particles of the second embodiment, in the method for producing composite particles comprising inorganic core particles and organic fine particles, the inorganic core particles mainly composed of inorganic material and the organic fine particles mainly composed of organic material. A particle adhering step for forming a particle adhering body in which organic fine particles adhere to the surface of the inorganic core particles from a dispersion liquid containing a reactive substance present on the surface of the organic fine particles in the dispersion liquid in which the particle adhering body is formed Addition of a silane coupling agent that interacts with the bonding group and binds (condenses) with a hydroxyl group (OH group) present on the surface of the inorganic core particle under basic conditions, and a basic substance A composite particle forming step of forming composite particles in which organic fine particles are fixed on the surface of the composite particles.
In the particle adhering body forming step, organic fine particles are present on the inorganic core particles by hetero-aggregation, and a particle adhering body in which the organic fine particles are electrostatically attached to the surface of the inorganic core particles is formed. By the inorganic material layer N formed by the action of the silane coupling agent, composite particles in which organic fine particles are immobilized on the surface of the inorganic core particles can be formed. This composite particle can have each of the physical properties described above.
Therefore, according to the method for producing composite particles of Embodiment 2, it is possible to produce composite particles that have high adhesion strength of organic fine particles onto inorganic core particles, and that can ensure a good charge amount and high fluidity.

  According to the external additive for toner of Embodiment 2, the composite particles described above are included. Therefore, this external additive for toner has high adhesion strength of organic fine particles onto the inorganic core particles, and can secure a good charge amount and high fluidity. The adhesion between the external additive and the toner particles can be maintained, the transfer efficiency can be maintained at a high level, and the external additive for the toner is difficult to be separated from the toner particles, thereby suppressing image defects caused by the contamination of the member, Stable image quality can be provided.

EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, each Example does not limit this invention.
The following examples explain the case where the composite particles according to the present invention are used as an external additive for toner.
Prior to the description of Examples and Comparative Examples, the contents of various measurement methods and evaluation tests in Examples and Comparative Examples will be described.

<How to find the average particle size>
The average particle diameters of the composite particles, the core particles before composite formation, and the fine particles were determined by SEM image observation as follows.
1. Average particle diameter of composite particles In SEM image observation, the SEM images of a total of 100 composite particles were binarized while changing the field of view of the SEM images, and the binarized image of the obtained composite particles was obtained. Obtained.
Based on the binarized image, after obtaining the assumed maximum inscribed circle (indicated by the inner dashed line in FIG. 3) from the circular contour of the composite particle cross section shown in FIG. 3, the average particle diameter of the composite particles is The diameter D of the portion (indicated by the outer broken line in FIG. 3) farthest from the assumed maximum inscribed circle was obtained.
2. Average particle size of core particles and fine particles before complexing In this case as well, SEM images of 100 core particles or fine particles in total are used in the same manner as described above, using SEM image observation and changing the field of view of the SEM images. Were binarized, and the obtained binarized image of the core particles or fine particles was obtained. As shown in FIG. 4 based on such a binarized image, the diameter DA of the core particle or the diameter DB of the fine particle is an orthogonal line to any two strings (strings X and Y shown in FIG. 4). It was determined as twice the distance between the intersection of (perpendicular line) and the position farthest from the intersection in the substantially circular portion corresponding to the particle surface.

<Evaluation of volume resistance and surface resistance of composite particles>
The measured values of volume resistance and surface resistance were determined by the following methods.
1. Measurement of volume resistance First, 10 g of composite particles and 3.3 g of a thermosetting epoxy resin (SPECIFIX-20 (trade name), Stolmouth) are added to 10 g of methanol, and the composite particles are added to the thermosetting epoxy resin. The kneaded material obtained by dispersing and kneading was pulverized for 1 hour using a pestle and mortar. The obtained gel-like substance is poured into a mold, molded by applying a pressure of 20 MPa using a hydraulic press machine, and then the molded product is dried at 80 ° C. for 12 hours. From the composite of composite particles and epoxy resin The resulting pellet was obtained. Electrodes were attached to both sides of the obtained pellets using silver paste to constitute a volume resistance measurement circuit shown in FIG. 5, and the volume resistance was determined. Perform the same measurement by changing the compounding ratio of composite particles and epoxy resin in the pellet, draw a calibration curve based on the change in volume resistance with respect to the epoxy resin ratio, and the value of the intercept of the coordinate axis where this calibration curve intersects (epoxy resin The volume resistivity when the ratio of 0 is 0%) was calculated as the volume resistivity (Ω · cm) of the composite particles.
2. Measurement of surface resistance As for surface resistance, a surface resistance measurement circuit shown in FIG. 6 is constructed using the same pellets as described above, and the surface resistance (Ω / cm ² ) of the composite particles is determined by the same method as described above. It was measured.
<Measurement of relative dielectric constant of composite particles>
The relative dielectric constant of the composite particles was determined by the following method.
Measure the dielectric constant with the above-mentioned dielectric constant measuring device by changing the compounding ratio of the composite particles and epoxy resin in the above pellets, draw a calibration curve based on the change in dielectric constant with respect to the epoxy resin ratio, and this calibration curve intersects The value of the intercept of the coordinate axis (dielectric constant when the epoxy resin ratio is 0%) was determined as the dielectric constant ε (F / m) of the composite particles. Thereafter, the ratio of the dielectric constant ε of the composite particles to the dielectric constant ε _{0 of} vacuum (about 8.854 × 10 ⁻¹² F / m) (relative dielectric constant of the composite particles: εr = ε / ε ₀ ) was calculated.

<Evaluation of charge amount of composite particles>
30 parts by mass of ferrite particles (volume average particle diameter: 35 μm) coated with styrene / methyl methacrylate resin are weighed in a glass bottle with a lid, and then 1 part by mass of composite particles are weighed on the ferrite particles. did. After that, it was allowed to stand under normal temperature and normal humidity (25 ° C./50% RH) and seasoned for 24 hours, and then stirred and shaken with a turbuler mixer for 3 minutes. The resulting load was applied. The charge amount (μC / g) of the particles was measured with a flying charge amount measuring device (electric field flying charge amount measuring device II-DC electric field (trade name), manufactured by DIT Corporation). The volume average particle size of the ferrite particles was measured using a particle size distribution measuring device (Multisizer (registered trademark), manufactured by Beckman Coulter, Inc.).

<Evaluation of adhesion strength of fine particles on core particles in composite particles>
First, for 100 composite particles in a dried state, the number of fine particles present on the surface of the core particle was measured by SEM image observation (number before ultrasonic irradiation).
On the other hand, using the same composite particles, a composite particle dispersion was prepared by dispersing in water at a blending ratio of 1% by weight of the composite particles. Thereafter, the composite particle dispersion was irradiated with ultrasonic waves for 30 minutes under conditions of an output of 110 W and a frequency of 31 kHz. Thereafter, the composite particle dispersion was subjected to solid-liquid separation by centrifugal sedimentation, the sediment was collected, and the sediment was dried by freeze drying. With respect to 100 composite particles in the dried solid, the number of fine particles present in the core particles was measured by SEM image observation (number after ultrasonic irradiation).
The number change (%) before and after ultrasonic irradiation was determined by comparing the number before and after ultrasonic irradiation obtained in this way.
A: The number change is 0.5% or more and less than 3%, the adhesion strength of the fine particles on the core particles is extremely high, and it is judged that the fine particles are fixed to the core particles by the extremely high adhesion strength (use suitably) Yes).
B: The number change is 3% or more and less than 5, the adhesion strength of the fine particles on the core particles is high, and it is determined that the fine particles are fixed to the core particles due to the high adhesion strength (can be used sufficiently).
C: The change in the number is 5% or more and less than 10%, the adhesion strength of the fine particles on the core particles is low, and it is judged that the fine particles are adhered on the core particles due to the low adhesion strength. Level to separate).
D: The number change is 10% or more, the adhesion strength of the fine particles on the core particles is extremely low, and it is judged that the fine particles are adhered on the core particles due to the extremely low adhesion strength (regardless of the application, Unsuitable level).

<Evaluation of fluidity of composite particles>
To 100 parts by weight of acrylic particles (MX-1000 (trade name), manufactured by Soken Chemical Co., Ltd.), 2 parts by weight of the composite particles are added, blended at 10,000 rpm for 30 seconds in a sample mill, and 102 parts by weight of the particle mixture is added. Obtained. Out of 102 parts by weight of the obtained particle mixture, 2.0 parts by mass of composite particles were weighed in a glass bottle with a lid for evaluation, and allowed to stand under normal temperature / normal humidity (23 ° C./50% RH) for 24 hours. Then, the initial degree of aggregation was measured with a powder tester (trade name, manufactured by Hosokawa Micron Corporation) equipped with a three-stage sieve. Further, 1 part by weight of particles separated from 100 parts by weight of the remaining particle mixture and 30 parts by weight of ferrite particles (volume average particle diameter: 35 μm) coated with styrene / methyl methacrylate resin are weighed in a glass bottle with a lid, The durability test for the above composite particles was performed by stirring and shaking with a tumbler mixer in an environment of normal temperature / normal humidity (23 ° C./50% RH) for 1 hour. Thereafter, the degree of agglomeration after the durability test was measured with the above-described powder tester for the composite particles remaining after the ferrite particles were removed with a magnet, and the change in the degree of agglomeration relative to the initial degree of aggregation was determined. This endurance test gives stress to the composite particles due to collision with ferrite particles having a specific gravity larger than that of the composite particles. When the composite particles cannot maintain the spherical shape due to the stress or adhere to the ferrite resin, the composite particles lose fluidity and the degree of aggregation changes greatly. The volume average particle size of the ferrite particles was measured using a particle size distribution measuring device (Multisizer (registered trademark), manufactured by Beckman Coulter, Inc.).
A: The change in the degree of aggregation is less than 10%, and it is judged that extremely high fluidity is ensured even after the durability test (preferably usable).
B: The change in aggregation degree is 10% or more and less than 20%, and it is judged that high fluidity is ensured even after the durability test (can be used sufficiently).
C: The change in the degree of aggregation is 20% or more and less than 30%, and it is determined that there are not a few particles that have lost fluidity after the durability test (the level at which use is determined depending on the application).
D: It is judged that the change in aggregation degree is 30% or more, and there are many particles that have lost fluidity after the endurance test (a level unsuitable for use regardless of application).

Below, the formation method of an organic particle and an inorganic particle is demonstrated.
The organic particles are formed by the following synthesis examples 1 to 6, and are used as either core particles or fine particles to constitute a part of the composite particles. The inorganic particles are formed by the following synthesis examples 7 to 12, and are used as either fine particles or core particles to constitute a part of the composite particles.

Synthesis Example 1
<Synthesis of organic particles>
2400 g of water was added to a 3 liter reaction vessel equipped with a cooler, a thermometer, and a nitrogen introduction tube, and nitrogen gas was introduced into the reaction vessel for 1 hour to remove oxygen in the reaction vessel. Thereafter, 150 g of methyl methacrylate (MMA) (manufactured by Tokyo Chemical Industry), 5 g of sodium p-styrenesulfonate (NaSS) as a particle size control agent, and 30 g of 3- (trimethoxysilyl) propyl methacrylate (MAPTMS) were added. Thereafter, 5 g of potassium persulfate (KPS) as a reaction initiator was added and reacted at 80 ° C. for 6 hours to obtain polymethyl methacrylate (PMMA) particles crosslinked by MAPTMS as organic particles.
Thereafter, the PMMA particles were separated into solid and liquid by centrifugal sedimentation, and the supernatant was removed by decantation. Then, 500 g of distilled water was added and stirred for 1 hour to obtain a dispersion. A series of operations of adding 500 g of distilled water, solid-liquid separation by centrifugal sedimentation, and decantation of the supernatant was repeated 3 times in total, and finally 820 g of water was added to obtain an aqueous dispersion of PMMA particles. The obtained PMMA particles had an average particle size of 80 nm as observed by SEM image, and the coefficient of variation of the average particle size was 5%.
Table 1 below shows a list of blending amounts of MMA, NaSS, MAPTMS, KPS, and water described in Synthesis Example 1.

Synthesis Examples 2-5
Except for changing the blending amounts of MMA, NaSS, MAPTMS, KPS, and water to the blending amounts shown in Table 1 below, PMMA particles (average by SEM image observation) as organic particles in the same manner as in Synthesis Example 1 (Particle diameter: 8 nm to 300 nm, variation coefficient of core average particle diameter: 2% to 10%) was synthesized.

Synthesis Example 6
<Synthesis of silica particles>
In a 5 liter reaction vessel equipped with a cooler, a thermometer, and a nitrogen inlet tube, 1250 g of ethanol, 1250 g of acetonitrile and 178 g of tetraethoxysilane are placed, controlled at 50 ° C. and stirred at 150 rpm, and 600 g of distilled water. And a 10% aqueous ammonia 40 g mixture were heated to 50 ° C. and immediately added all at once. Then, after stirring for 10 hours at 50 ° C., 1000 g of distilled water was added, concentrated using an evaporator until the liquid volume became half, and solid-liquid separation was performed by centrifugal sedimentation. After removing the supernatant by decantation, 800 g of distilled water was added and stirred for 1 hour, and solid-liquid separation was performed in the same manner. A series of operations of adding 800 g of distilled water, solid-liquid separation by centrifugal sedimentation, and decantation of the supernatant was repeated 3 times in total. Finally, 200 g of water was added and silica particles (average particle diameter by SEM image observation: 20 nm) A white dispersion liquid in which a coefficient of variation in average particle diameter: 10%) was dispersed was obtained.
Table 2 below shows a list of blending amounts of ethanol, acetonitrile, tetraethoxysilane, water, and 10% ammonia described in Synthesis Example 6.

Synthesis Examples 6 to 11
Silica particles (average by SEM image observation) as inorganic particles in the same manner as in Synthesis Example 7 except that the amounts of tetraethoxysilane, water, and 10% ammonia described above were changed to the amounts shown in Table 2 below. (Particle diameter: 9 to 290 nm, coefficient of variation of average particle diameter of core particles: 2% to 10%) was synthesized.

Synthesis Example 12
<Synthesis of strontium titanate>
A reaction vessel was prepared in the glove box, and 18 g of metal strontium (manufactured by Nacalai Tex Co., Ltd.) was dissolved in 1100 g of 2-methoxyethanol (manufactured by Wako Pure Chemical Industries, Ltd.). After the metal strontium was completely dissolved, 48 g of titanium tetraethoxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the lid was taken out from the glove box.
Next, a strontium titanate dispersion was obtained by installing a cooler, a thermometer, and a nitrogen introduction tube in the reaction vessel and refluxing for 2 hours in a nitrogen atmosphere. Thereafter, 1000 g of distilled water was added, the solution was concentrated using an evaporator until the liquid volume was reduced to half, and solid-liquid separation was performed by centrifugal sedimentation. After removing the supernatant by decantation, 800 g of distilled water was added and stirred for 1 hour, and solid-liquid separation was performed in the same manner. A series of operations of adding 800 g of distilled water, solid-liquid separation by centrifugal sedimentation, and decantation of the supernatant was repeated a total of 3 times, and finally 200 g of water was added to disperse strontium titanate having a particle size of 18 nm. A liquid was obtained.
Table 2 below shows the blending amounts of strontium, 2-methoxyethanol, and titanium tetraethoxide of Synthesis Example 13 described above.

Examples 1-1 to 1-14
Examples 1-1 to 1-14 are production examples of composite particles including one kind of organic core particles and one kind of inorganic fine particles.

Example 1-1
<Production of composite particles>
1. Particle adhering body forming step 555 g of an organic particle dispersion containing 100 g of PMMA particles (average particle diameter: 80 nm) synthesized in Synthesis Example 1 at a liquid temperature of 30 ° C. in a reaction vessel equipped with a cooler, a thermometer, and a nitrogen introduction tube. And 1565 g of an inorganic fine particle dispersion containing 313 g of silica fine particles (average particle size: 20 nm) synthesized in Synthesis Example 6 at a liquid temperature of 30 ° C. were mixed to obtain a dispersion. Thereafter, distilled water was added until the total amount of the dispersion became 2500 g. Thereafter, the dispersion was stirred for 3 hours while being kept at 30 ° C. Thereafter, while measuring the pH of the dispersion with the liquid temperature and stirring maintained, a 0.1 M hydrochloric acid solution was continuously added dropwise over 2 hours until the pH reached 2.0. When the pH reached 2.0, the hydrochloric acid was added dropwise. Stopped. Then, after heating up to 60 degreeC, it stirred at 60 degreeC for 5 hours, and the particle | grain adhesion body which made the silica fine particle adhere to PMMA particle | grains was formed.

2. Composite particle formation step After cooling the dispersion with the particle adhering body formed to room temperature, 50.0 g of MAPTMS was added to the dispersion at a stretch and stirred for 10 hours until 10% aqueous ammonia was adjusted to pH 8.0. And gradually dropped. After confirming that the dispersion became pH 8.0, the temperature was raised to 50 ° C. while maintaining the pH, and the reaction was carried out at 50 ° C. for 6 hours to immobilize silica fine particles on the surface of the PMMA particles. Got.
Then, after solid-liquid separation by centrifugal sedimentation, the supernatant was removed by decantation, 500 g of distilled water was added, and the mixture was stirred for 1 hour to obtain a dispersion again. A series of operations of adding 500 g of distilled water, solid-liquid separation by centrifugal sedimentation, and decantation of the supernatant was repeated a total of 3 times, and finally solid-liquid separation was performed again by centrifugation, and the precipitate was freeze-dried for 24 hours. This gave a white powder.

3. Particle hydrophobization step Thereafter, 10 g of the white powder obtained by the composite particle formation step is added to a mixture of 200 g of water and 15 g of hexamethyldisilazane (HMDS), stirred at room temperature for 30 minutes, and further at 60 ° C. for 4 hours. After stirring, solid-liquid separation is performed, and the resulting precipitate is washed with methanol, and then dried at 50 ° C. for 48 hours, whereby white particles of composite particles whose surfaces are hydrophobized (average by SEM image observation) Particle size: 122 nm) was obtained.
Table 3 below shows a list of blending amounts of organic particles, inorganic particles, water, MAPTMS, and HMDS in Example 1-1.

<Confirmation of physical properties of composite particles of Example 1-1>
The average particle diameter of the core particles, the coefficient of variation thereof, the fine particle average particle diameter / core particle average particle diameter, the resistance ratio ρr, the average particle diameter of the composite particles, the relative dielectric constant, and the coverage of the composite particles of Example 1-1. Each physical property value is shown in Table 1, Table 2 and Table 3 below. Further, as can be seen from the evaluation of the adhesion strength of the fine particles to the core particles, the number change was less than 3%.
Thereby, it confirmed that the composite particle of Example 1-1 had the above-mentioned physical property (1)-(8).
<Evaluation of Composite Particles of Example 1-1>
The evaluation of the adhesion strength of the fine particles with respect to the core particles and the fluidity evaluation by changing the degree of aggregation of the composite particles of Example 1-1 were both “A” evaluation. Further, it was confirmed that the composite particles of Example 1-1 had a good charge amount.

Examples 1-2 to 1-11
<Production of Composite Particles of Examples 1-2 to 1-11>
As composite particles of these Examples 1-2 to 1-11, except that the blending amounts of organic particles, silica particles, and water are changed to blending amounts shown in Table 3 below, they are the same as those of Example 1-1. The composite particles produced by the method were used.

Example 1-12
<Production of Composite Particles of Example 1-12>
In Example 1-12, composite particles produced by the same method as in Example 1-1 were used except that the silica particles were changed to strontium titanate synthesized in Synthesis Example 12.

Example 1-13
<Production of Composite Particles of Example 1-13>
Further, in Example 1-13, the silica particles were changed to titanium oxide SRD-02W (manufactured by Sakai Chemical Industry Co., Ltd.): average particle diameter of 9 nm, and the same method as in Example 1-1 was used. The produced composite particles were used.

Example 1-14
<Production of Composite Particles of Example 1-14>
Further, in Example 1-14, the silica particle was cerium oxide TECNADIS-CE-115 (manufactured by TECNAN): a composite produced by the same method as in Example 1-1 except that the average particle diameter was changed to 5 nm. Particles were used.

  Table 3 below shows a list of blending amounts of organic particles, inorganic particles, water, MAPTMS, and HMDS in Examples 1-2 to 1-14.

<Confirmation of physical properties of composite particles of Examples 1-2 to 1-14>
For each composite particle of Examples 1-2 to 1-14, the average particle diameter of the core particles, the coefficient of variation thereof, the fine particle average particle diameter / core particle average particle diameter, the resistance ratio ρr, the average particle diameter of the composite particles, the ratio The physical properties of dielectric constant and coverage are shown in Table 1, Table 2 and Table 3 below.
Examples 1-2, 1-3, 1-5, 1-6, 1-8, 1-9, 1-11 to 1-14, as seen from the evaluation of the adhesion strength of the fine particles to the core particles Further, the number change is less than 3%, and as can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of each of the composite particles of Examples 1-4, 1-7, and 1-10, the number change is 3% or more and 5 %.
Thereby, it was confirmed that each of the composite particles of Examples 1-2 to 1-14 has the above physical properties (1) to (8).
<Evaluation of Composite Particles of Examples 1-2 to 1-14>
Of the composite particles of Examples 1-2 to 1-14, except that the adhesion strength evaluation of the fine particles to the core particles of Examples 1-4, 1-7, and 1-10 was “B” evaluation, Was also rated “A”.
Among the composite particles of Examples 1-2 to 1-14, except that the fluidity evaluation by changing the aggregation degree of Examples 1-4, 1-7, 1-10, 1-13 was “B” evaluation. All were "A" evaluation.
It was confirmed that all the composite particles of Examples 1-2 to 1-14 had a good charge amount.

Examples 2-1 to 2-8
Examples 2-1 to 2-8 are production examples of composite particles including one kind of inorganic core particles and one kind of organic fine particles.

Example 2-1
<Production of Composite Particles of Example 2-1>
1. Particle Adherent Forming Step 500 g of inorganic particle dispersion containing 100 g of silica particles (average particle size: 110 nm) synthesized in Synthesis Example 9 at a liquid temperature of 30 ° C. in a reaction vessel equipped with a cooler, a thermometer, and a nitrogen introduction tube. Then, 888 g of an organic fine particle dispersion containing 160 g of PMMA fine particles (average particle size: 8 nm) synthesized in Synthesis Example 5 at a liquid temperature of 30 ° C. were mixed to obtain a dispersion. Thereafter, distilled water was added until the total amount of the dispersion became 2500 g. Thereafter, the dispersion was stirred for 3 hours while being kept at 30 ° C. Thereafter, while measuring the pH of the dispersion with the liquid temperature and stirring maintained, a 0.1 M hydrochloric acid solution was continuously added dropwise over 2 hours until the pH reached 2.0. When the pH reached 2.0, the hydrochloric acid was added dropwise. Stopped. Then, after heating up to 60 degreeC, the PMMA fine particle was made to adhere to the silica core particle surface by stirring at 60 degreeC for 5 hours.

2. Composite particle forming step After the dispersion liquid in which the particle adhering body is formed is cooled to room temperature, 50.0 g of MAPTMS is added to the dispersion liquid all at once, and while stirring, 2% until 10% aqueous ammonia becomes pH 8.0. It was dripped gradually over the time. After confirming that the dispersion reached pH 8.0, a particle adhering body in which silica particles were immobilized on the surface of the core particles was obtained by reacting at room temperature for 6 hours while maintaining the pH.
Thereafter, 100 g of distilled water was added, concentrated using an evaporator until the liquid volume was reduced to half, and solid-liquid separation was performed by centrifugal sedimentation. After removing the supernatant by decantation, 300 g of distilled water was added, and solid-liquid separation was performed in the same manner. A series of operations of 300 g of distilled water, solid-liquid separation by centrifugal sedimentation, and decantation of the supernatant was repeated a total of 3 times, and then the precipitate was freeze-dried for 24 hours to obtain a white powder.

3. Particle hydrophobization step Thereafter, 10 g of the white powder obtained by the composite particle formation step is added to a mixture of 200 g of water and 15 g of hexamethyldisilazane (HMDS), stirred at room temperature for 30 minutes, and further at 60 ° C. for 4 hours. After stirring, solid-liquid separation is performed, and the resulting precipitate is washed with methanol, and then dried at 50 ° C. for 48 hours, whereby white particles of composite particles whose surfaces are hydrophobized (average by SEM image observation) Particle size: 125 nm) was obtained.
Table 4 below shows a list of blending amounts of organic particles, inorganic particles, water, MAPTMS, and HMDS in Example 2-1.

<Confirmation of physical properties of composite particles of Example 2-1>
The average particle diameter of the core particles, the coefficient of variation thereof, the fine particle average particle diameter / core particle average particle diameter, the resistance ratio ρr, the average particle diameter of the composite particles, the relative dielectric constant, and the coverage of the composite particles of Example 2-1. Each physical property value is shown in Table 1, Table 2 and Table 4 below. Further, as can be seen from the evaluation of the adhesion strength of the fine particles to the core particles, the number change was less than 3%.
Thereby, it confirmed that the composite particle of Example 2-1 had the said physical property (1)-(8) together.
<Evaluation of Composite Particles of Example 2-1>
The evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Example 2-1 was “B” evaluation, and the fluidity evaluation by change in the degree of aggregation was “A” evaluation. In addition, it was confirmed that the composite particles of Example 2-1 had a good charge amount.

Examples 2-2 to 2-8
<Production of Composite Particles of Examples 2-2 to 2-8>
As composite particles of these Examples 2-2 to 2-8, except that the blending amounts of organic particles, inorganic particles, and water are changed to blending amounts shown in Table 4 below, the same as in Example 2-1. The composite particles produced by the method were used.
Table 4 below shows a list of blending amounts of organic particles, inorganic particles, water, MAPTMS, and HMDS in Examples 2-2 to 2-8.

<Confirmation of physical properties of composite particles of Examples 2-2 to 2-8>
For each composite particle of Examples 2-2 to 2-8, the average particle diameter of the core particle, its coefficient of variation, fine particle average particle diameter / core particle average particle diameter, resistance ratio ρr, average particle diameter of the composite particle, ratio The physical properties of dielectric constant and coverage are shown in Table 1, Table 2 and Table 4 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of each of the composite particles of Examples 2-2 to 2-8, the number change was less than 3%.
Thereby, it was confirmed that each of the composite particles of Examples 2-2 to 2-8 also has the above physical properties (1) to (8).
<Evaluation of Composite Particles of Examples 2-2 to 2-8>
Evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Examples 2-2 to 2-8 was “A” evaluation.
Among the composite particles of Examples 2-2 to 2-8, all were “A” evaluations except that the fluidity evaluation by the change in aggregation degree of Example 2-5 was “B” evaluation.
It was confirmed that each of the composite particles of Examples 2-2 to 2-8 had a good charge amount.

Examples 3-1 to 3-6
Examples 3-1 to 3-6 are examples of producing composite particles including one type of organic core particle, one type of inorganic fine particle, and one type of organic fine particle.

Example 3-1.
<Production of Composite Particles of Example 3-1>
1. Particle adhering body forming step 555 g of an organic particle dispersion containing 100 g of PMMA particles (average particle diameter: 80 nm) synthesized in Synthesis Example 1 at a liquid temperature of 30 ° C. in a reaction vessel equipped with a cooler, a thermometer, and a nitrogen introduction tube. Then, 400 g of an inorganic particle dispersion containing 80 g of silica fine particles (average particle size: 20 nm) synthesized in Synthesis Example 6 at a liquid temperature of 30 ° C. and 1564 g of distilled water were mixed to obtain a dispersion. Thereafter, the dispersion was stirred for 3 hours while being kept at 30 ° C. Thereafter, while measuring the pH of the dispersion with the liquid temperature and stirring maintained, a 0.1 M hydrochloric acid solution was continuously added dropwise over 2 hours until the pH reached 2.0. When the pH reached 2.0, the hydrochloric acid was added dropwise. Stopped. Then, after heating up to 60 degreeC, the silica fine particle was made to adhere to the PMMA core particle surface by stirring at 60 degreeC for 5 hours.
Thereafter, 194 g of a dispersion liquid containing 35 g of PMMA fine particles (average particle size: 8 nm) synthesized in Synthesis Example 5 that had been heated to 60 ° C. in advance was immediately added and stirred at 60 ° C. for 5 hours. A particle adhering body in which PMMA fine particles were further adhered to the surface of the PMMA core particles having silica fine particles adhered to the surface was formed. In this step, distilled water was added until the total amount of the dispersion reached 2500 g, and the total amount of the distilled water was 2285 g.

2. Composite particle forming step After the dispersion liquid in which the particle adhering material has been formed is cooled to room temperature, 10.0 g of MAPTMS is added to the dispersion liquid at once, and 10% aqueous ammonia is gradually added to pH 8.0 over 2 hours. It was dripped. After confirming that the dispersion reached pH 8.0, the mixture was reacted at room temperature for 6 hours while maintaining the pH to obtain composite particles in which silica fine particles and PMMA fine particles were immobilized on the surface of the PMMA core particles.
Thereafter, 100 g of distilled water was added and concentrated using an evaporator until the liquid volume was reduced to half, and the product was subjected to solid-liquid separation by centrifugal sedimentation. After removing the supernatant by decantation, 300 g of distilled water was added, and solid-liquid separation was performed in the same manner. A series of operations of 300 g of distilled water, solid-liquid separation by centrifugal sedimentation, and decantation of the supernatant was repeated a total of 3 times, and then the precipitate was freeze-dried for 24 hours to obtain a white powder.

3. Particle hydrophobization step Thereafter, 10 g of the white powder obtained by the composite particle formation step is added to a mixture of 200 g of water and 15 g of hexamethyldisilazane (HMDS), stirred at room temperature for 30 minutes, and further at 60 ° C. for 4 hours. After stirring, solid-liquid separation is performed, and the resulting precipitate is washed with methanol, and then dried at 50 ° C. for 48 hours, whereby white particles of composite particles whose surfaces are hydrophobized (average by SEM image observation) Particle size: 123 nm) was obtained.
Table 5 below shows a list of blending amounts of organic particles, inorganic particles, water, MAPTMS, and HMDS in Example 3-1.

<Confirmation of physical properties of composite particles of Example 3-1>
The average particle diameter of the core particles, the coefficient of variation thereof, the fine particle average particle diameter / core particle average particle diameter, the resistance ratio ρr, the average particle diameter of the composite particles, the relative dielectric constant, and the coverage of the composite particles of Example 3-1. Each physical property value is shown in Table 1, Table 2 and Table 5 below. Further, as can be seen from the evaluation of the adhesion strength of the fine particles to the core particles, the number change was less than 3%.
Thereby, it was confirmed that the composite particles of Example 3-1 also have the above physical properties (1) to (8).
<Evaluation of Composite Particles of Example 3-1>
The evaluation of the adhesion strength of the fine particles with respect to the core particles and the fluidity evaluation by changing the degree of aggregation of the composite particles of Example 3-1 were both “A” evaluations. Further, it was confirmed that the composite particles of Example 3-1 had a good charge amount.

Examples 3-2 to 3-6
<Production of Composite Particles of Examples 3-2 to 3-6>
As composite particles of these Examples 3-2 to 3-6, except that the blending amounts of organic particles, inorganic particles, and water were changed to blending amounts shown in Table 5 below, the same as in Example 3-1. The composite particles produced by the method were used.
Table 5 below shows a list of blending amounts of organic particles, inorganic particles, water, MAPTMS, and HMDS in Examples 3-2 to 3-6.

<Confirmation of physical properties of composite particles of Examples 3-2 to 3-6>
For each composite particle of Examples 3-2 to 3-6, the average particle diameter of the core particles, the coefficient of variation thereof, the fine particle average particle diameter / core particle average particle diameter, the resistance ratio ρr, the average particle diameter of the composite particles, The physical properties of dielectric constant and coverage are shown in Table 1, Table 2 and Table 5 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of each of the composite particles of Examples 3-2 to 3-6, the number change was less than 3%.
Thereby, it was confirmed that each of the composite particles of Examples 3-2 to 3-6 has the above physical properties (1) to (8).
<Evaluation of Composite Particles of Examples 3-2 to 3-6>
Evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Examples 3-2 to 3-6 was “A” evaluation.
Among the composite particles of Examples 3-2 to 3-6, except that the fluidity evaluation by the change in aggregation degree of Examples 3-2 and 3-5 was “B” evaluation, all were “A” evaluations. there were.
It was confirmed that all the composite particles of Examples 3-2 to 3-6 had a good charge amount.

Examples 4-1 to 4-6
Examples 4-1 to 4-6 are production examples of composite particles including inorganic core particles, one kind of organic fine particles, and one kind of inorganic fine particles.

Example 4-1
<Production of composite particles of Example 4-1>
1. Particle Adherent Forming Step 500 g of inorganic particle dispersion containing 100 g of silica particles (average particle size: 110 nm) synthesized in Synthesis Example 9 at a liquid temperature of 30 ° C. in a reaction vessel equipped with a cooler, a thermometer, and a nitrogen introduction tube. Then, 167 g of an organic fine particle dispersion containing 30 g of PMMA fine particles (average particle size: 8 nm) synthesized in Synthesis Example 5 at a liquid temperature of 30 ° C. and 1863 g of distilled water were mixed to obtain a dispersion. Thereafter, the dispersion was stirred for 3 hours while being kept at 30 ° C. Then, while measuring the pH of the dispersion with the liquid temperature and stirring speed maintained, 0.1M hydrochloric acid solution was continuously added dropwise over 2 hours until the pH reached 2.0. The dripping was stopped. Then, after heating up to 60 degreeC, the PMMA fine particle was made to adhere to the silica core particle surface by stirring at 60 degreeC for 5 hours.
Thereafter, 125 g of a dispersion containing 25 g of silica fine particles (average particle size: 20 nm) synthesized in Synthesis Example 6 that had been heated to 60 ° C. in advance was immediately added, and the mixture was stirred at 60 ° C. for 5 hours. A particle adhering body in which silica fine particles were further adhered to the surface of silica core particles having PMMA fine particles adhered to the surface was formed. In this step, distilled water was added until the total amount of the dispersion reached 2500 g, and the total amount of the distilled water was 2345 g.

2. Composite particle forming step After the dispersion liquid in which the particle adhering material has been formed is cooled to room temperature, 10.0 g of MAPTMS is added to the dispersion liquid at once, and 10% aqueous ammonia is gradually added to pH 8.0 over 2 hours. It was dripped. After confirming that the dispersion reached pH 8.0, the reaction was allowed to proceed at room temperature for 6 hours while maintaining the pH to obtain composite particles in which the PMMA fine particles and silica fine particles were immobilized on the surface of the silica core particles.
Thereafter, 100 g of distilled water was added, concentrated using an evaporator until the liquid volume was reduced to half, and solid-liquid separation was performed by centrifugal sedimentation. After removing the supernatant by decantation, 300 g of distilled water was added, and solid-liquid separation was performed in the same manner. A series of operations of 300 g of distilled water, solid-liquid separation by centrifugal sedimentation, and decantation of the supernatant was repeated a total of 3 times, and then the precipitate was freeze-dried for 24 hours to obtain a white powder.

3. Particle hydrophobization step Thereafter, 10 g of the white powder obtained by the composite particle formation step is added to a mixture of 200 g of water and 15 g of hexamethyldisilazane (HMDS), stirred at room temperature for 30 minutes, and further at 60 ° C. for 4 hours. After stirring, solid-liquid separation is performed, and the resulting precipitate is washed with methanol, and then dried at 50 ° C. for 48 hours, whereby the white particles of the composite particles whose surfaces are hydrophobized (average particles by SEM image observation) Diameter: 153 nm).
Table 6 below shows a list of blending amounts of organic particles, inorganic particles, water, MAPTMS, and HMDS in Example 4-1.

<Confirmation of physical properties of composite particles of Example 4-1>
The average particle diameter of the core particles, the coefficient of variation thereof, the fine particle average particle diameter / core particle average particle diameter, the resistance ratio ρr, the average particle diameter of the composite particles, the relative dielectric constant, and the coverage of the composite particles of Example 4-1. Each physical property value is shown in Table 1, Table 2 and Table 6 below. Further, as can be seen from the evaluation of the adhesion strength of the fine particles to the core particles, the number change was less than 3%.
Thus, it was confirmed that the composite particles of Example 4-1 had the above physical properties (1) to (8).
<Evaluation of Composite Particles of Example 4-1>
The evaluation of the adhesion strength of the fine particles to the core particles and the evaluation of the fluidity by changing the degree of aggregation of the composite particles of Example 4-1 were both “A” evaluations. Further, it was confirmed that the composite particles of Example 4-1 had a good charge amount.

Examples 4-2 to 4-6
<Production of Composite Particles of Examples 4-2 to 4-6>
As composite particles of Examples 4-2 to 4-6, organic particles, inorganic particles, and water were mixed in the same amounts as in Example 4-1 except that the amounts shown in Table 6 below were changed. The composite particles produced by the method were used.
Table 6 below shows a list of blending amounts of organic particles, inorganic particles, water, MAPTMS, and HMDS in Examples 4-2 to 4-6.

<Confirmation of physical properties of composite particles of Examples 4-2 to 4-6>
For each composite particle of Examples 4-2 to 4-6, the average particle diameter of the core particles, the coefficient of variation thereof, the fine particle average particle diameter / core particle average particle diameter, the resistance ratio ρr, the average particle diameter of the composite particles, the ratio The physical properties of dielectric constant and coverage are shown in Table 1, Table 2 and Table 6 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of each of the composite particles of Examples 4-2 to 4-6, the number change was less than 3%.
Thereby, it was confirmed that each of the composite particles of Examples 4-2 to 4-6 also has the above physical properties (1) to (8).
<Evaluation of Composite Particles of Examples 4-2 to 4-6>
Evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Examples 4-2 to 4-6 was “A” evaluation.
Among the composite particles of Examples 4-2 to 4-6, all were “A” evaluations except that the fluidity evaluation based on the change in aggregation degree of Example 4-2 was “B” evaluation.
It was confirmed that all the composite particles of Examples 4-2 to 4-6 had a good charge amount.

Comparative Example 1
<Production of composite particles of Comparative Example 1>
As a composite particle of Comparative Example 1, a particle adhering material in which the silica fine particles (average particle size: 20 nm) synthesized in Synthesis Example 6 were adhered to the PMMA core particles (average particle size: 80 nm) synthesized in Synthesis Example 1 The composite particles produced by the same method as in Example 1-1 were used except that the surface treatment by MAPTMS was not performed.
Table 7 below shows a list of blending amounts of organic particles, inorganic particles, water, and HMDS in Comparative Example 1.

<Confirmation of physical properties of composite particles of Comparative Example 1>
Core particle average particle diameter, coefficient of variation thereof, fine particle average particle diameter / core particle average particle diameter, resistance ratio ρr, composite particle average particle diameter, relative dielectric constant, and coverage of the composite particles of Comparative Example 1 Values are shown in Table 1, Table 2 and Table 7 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Comparative Example 1, the number change is 5% or more and less than 10%, the resistance ratio ρr is 1.5, and the physical properties (5) It was confirmed that the numerical range was not satisfied.
<Evaluation of Composite Particles of Comparative Example 1>
In the composite particles of Comparative Example 1, the adhesion strength evaluation of the fine particles with respect to the core particles and the fluidity evaluation due to the change in the degree of aggregation were both “C” evaluations, and the charge amount was −320 lower than the appropriate range.
Therefore, it was confirmed that the composite particles of Comparative Example 1 had not a few particles that lost fluidity, and the amount of charge was small. This evaluation result is considered to be caused by the fact that the resistance ratio ρr of the composite particles of Comparative Example 1 does not satisfy the numerical range of the physical property (5).

Comparative Example 2
<Production of composite particles of Comparative Example 2>
As a composite particle of Comparative Example 2, the particle adhering body in which the silica fine particles (average particle size: 30 nm) synthesized in Synthesis Example 7 were adhered to the PMMA core particles (average particle size: 80 nm) synthesized in Synthesis Example 1 The composite particles produced by the same method as in Example 1-4 were used except that the surface treatment by MAPTMS was not performed.
Table 7 below shows a list of blending amounts of organic particles, inorganic particles, water, and HMDS in Comparative Example 2.

<Confirmation of physical properties of composite particles of Comparative Example 2>
Core particle average particle diameter, coefficient of variation thereof, fine particle average particle diameter / core particle average particle diameter, resistance ratio ρr, composite particle average particle diameter, relative dielectric constant, and coverage of the composite particles of Comparative Example 2 Values are shown in Table 1, Table 2 and Table 7 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Comparative Example 2, the number change is 10% or more, the resistance ratio ρr is 3, and the numerical values of the above physical properties (5) and (6) Confirmed that the range was not met.
<Evaluation of Composite Particles of Comparative Example 2>
The evaluation of the adhesion strength of the fine particles with respect to the core particles and the evaluation of the fluidity by changing the degree of aggregation of the composite particles of Comparative Example 2 were both “D” evaluation.
Therefore, it was confirmed that the composite particles of Comparative Example 2 had low adhesion strength and lost fluidity. This evaluation result is considered to result from the fact that the change in the number of composite particles and the resistance ratio ρr of Comparative Example 2 do not satisfy the numerical ranges of the physical properties (5) and (6).

Comparative Example 3
<Production of composite particles of Comparative Example 3>
As a composite particle of Comparative Example 3, a particle adhering material in which the silica fine particles (average particle size: 9 nm) synthesized in Synthesis Example 8 were attached to the PMMA core particles (average particle size: 80 nm) synthesized in Synthesis Example 1 The composite particles produced by the same method as in Example 1-5 were used except that the surface treatment by MAPTMS was not performed.
Table 7 below shows a list of blending amounts of organic particles, inorganic particles, water, and HMDS in Comparative Example 3.

<Confirmation of physical properties of composite particles of Comparative Example 3>
Core particle average particle diameter, coefficient of variation thereof, fine particle average particle diameter / core particle average particle diameter, resistance ratio ρr, composite particle average particle diameter, relative dielectric constant, physical properties of the composite particles of Comparative Example 3 Values are shown in Table 1, Table 2 and Table 7 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Comparative Example 3, the number change is 5% or more and less than 10%, the resistance ratio ρr is 1.6, and the above physical properties (5) and (6 ) Was not met.
<Evaluation of Composite Particles of Comparative Example 3>
In the composite particles of Comparative Example 3, the adhesion strength evaluation of the fine particles with respect to the core particles is “C” evaluation, the fluidity evaluation due to the change in aggregation degree is “B” evaluation, and the charge amount is −350 lower than the appropriate range. there were.
Therefore, it was confirmed that the composite particles of Comparative Example 3 had extremely low adhesion strength and lost fluidity. This evaluation result is considered to result from the fact that the change in the number of composite particles of Comparative Example 3 and the resistance ratio ρr do not satisfy the numerical ranges of the physical properties (5) and (6).

Comparative Example 4
<Production of Composite Particles of Comparative Example 4>
As a composite particle of Comparative Example 4, a particle adhering material in which the silica fine particles (average particle size: 20 nm) synthesized in Synthesis Example 6 were adhered to the PMMA core particles (average particle size: 205 nm) synthesized in Synthesis Example 2 was used. The composite particles produced by the same method as in Example 1-6 were used except that the surface treatment by MAPTMS was not performed.
Table 7 below shows a list of blending amounts of organic particles, inorganic particles, water, and HMDS in Comparative Example 4.

<Confirmation of physical properties of composite particles of Comparative Example 4>
Core particle average particle diameter, coefficient of variation thereof, fine particle average particle diameter / core particle average particle diameter, resistance ratio ρr, composite particle average particle diameter, relative dielectric constant, and physical properties of composite particles of Comparative Example 4 Values are shown in Table 1, Table 2 and Table 7 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Comparative Example 4, the number change is 5% or more and less than 10%, the resistance ratio ρr is 1.5, and the above physical properties (5) and It was confirmed that the numerical range of (6) was not satisfied.
<Evaluation of Composite Particles of Comparative Example 4>
In the composite particles of Comparative Example 4, the evaluation of the adhesion strength of the fine particles to the core particles and the evaluation of the fluidity due to the change in the degree of aggregation were both “C” evaluations, and the charge amount was −400, which was lower than the appropriate range.
Therefore, it was confirmed that the composite particles of Comparative Example 4 had low adhesion strength and lost fluidity. This evaluation result is considered to result from the fact that the change in the number of composite particles and the resistance ratio ρr of Comparative Example 4 do not satisfy the numerical ranges of the physical properties (5) and (6).

Comparative Example 5
<Production of Composite Particles of Comparative Example 5>
As a composite particle of Comparative Example 5, the particle adhering material in which the silica fine particles (average particle size: 20 nm) synthesized in Synthesis Example 6 were adhered to the PMMA core particles (average particle size: 300 nm) synthesized in Synthesis Example 3 The composite particles produced by the same method as in Example 1-9 were used except that the surface treatment by MAPTMS was not performed.
Table 7 below shows a list of blending amounts of organic particles, inorganic particles, water, and HMDS in Comparative Example 5.

<Confirmation of physical properties of composite particles of Comparative Example 5>
Core particle average particle diameter, coefficient of variation thereof, fine particle average particle diameter / core particle average particle diameter, resistance ratio ρr, composite particle average particle diameter, relative dielectric constant, and coverage of the composite particles of Comparative Example 5 Values are shown in Table 1, Table 2 and Table 7 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Comparative Example 5, the number change is 5% or more and less than 10%, the resistance ratio ρr is 1.5, and the physical properties (5) and It was confirmed that the numerical range of (6) was not satisfied.
<Evaluation of Composite Particle of Comparative Example 5>
The evaluation of the adhesion strength of the fine particles with respect to the core particles and the fluidity evaluation due to the change in the degree of aggregation of the composite particles of Comparative Example 5 were both “C” evaluation, and the charge amount was −330, which was lower than the appropriate range.
Therefore, it was confirmed that the composite particles of Comparative Example 5 had low adhesion strength and lost fluidity. This evaluation result is considered to result from the fact that the change in the number of composite particles and the resistance ratio ρr of Comparative Example 5 do not satisfy the numerical ranges of the physical properties (5) and (6).

Comparative Example 6
<Production of Composite Particles of Comparative Example 6>
As the composite particles of Comparative Example 6, the PMMA fine particles (average particle size: 8 nm) synthesized in Synthesis Example 5 were attached to the silica core particles (average particle size: 110 nm) synthesized in Synthesis Example 9 The composite particles produced by the same method as in Example 2-2 were used except that the surface treatment by MAPTMS was not performed.
Table 7 below shows a list of blending amounts of organic particles, inorganic particles, water, and HMDS in Comparative Example 6.

<Confirmation of physical properties of composite particles of Comparative Example 6>
Core particle average particle diameter, coefficient of variation thereof, fine particle average particle diameter / core particle average particle diameter, resistance ratio ρr, composite particle average particle diameter, relative dielectric constant, and coverage of the composite particles of Comparative Example 6 Values are shown in Table 1, Table 2 and Table 7 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Comparative Example 6, the number change is 5% or more and less than 10%, the resistance ratio ρr is 1.5, and the above physical properties (5) and It was confirmed that the numerical range of (6) was not satisfied.
<Evaluation of Composite Particle of Comparative Example 6>
In the composite particles of Comparative Example 6, the evaluation of the adhesion strength of the fine particles to the core particles and the evaluation of the fluidity due to the change in the degree of aggregation were both “C” evaluation, and the charge amount was −420, which was lower than the appropriate range.
Therefore, it was confirmed that the composite particles of Comparative Example 6 had low adhesion strength and lost fluidity. This evaluation result is considered to result from the fact that the change in the number of composite particles of Comparative Example 6 and the resistance ratio ρr do not satisfy the numerical ranges of the physical properties (5) and (6).

Comparative Example 7
<Production of Composite Particles of Comparative Example 7>
As the composite particles of Comparative Example 7, the PMMA fine particles (average particle size: 8 nm) synthesized in Synthesis Example 5 were adhered on the silica core particles (average particle size: 80 nm) synthesized in Synthesis Example 10 Composite particles produced by the same method as in Example 2-5 were used except that the surface treatment by MAPTMS was not performed.
Table 7 below shows a list of blending amounts of organic particles, inorganic particles, water, and HMDS in Comparative Example 7.

<Confirmation of physical properties of composite particles of Comparative Example 7>
Core particle average particle diameter, coefficient of variation thereof, fine particle average particle diameter / core particle average particle diameter, resistance ratio ρr, composite particle average particle diameter, relative dielectric constant, and coverage of the composite particles of Comparative Example 7 Values are shown in Table 1, Table 2 and Table 7 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Comparative Example 7, the number change is 10% or more, the resistance ratio ρr is 1.5, and the above physical properties (5) and (6) It was confirmed that the numerical range of was not satisfied.
<Evaluation of Composite Particle of Comparative Example 7>
In the composite particles of Comparative Example 7, the adhesion strength evaluation of the fine particles with respect to the core particles is “D” evaluation, the fluidity evaluation by the change in aggregation degree is “C” evaluation, and the charge amount is −460 lower than the appropriate range. there were.
Therefore, it was confirmed that the composite particles of Comparative Example 7 had extremely low adhesion strength and lost fluidity. This evaluation result is considered to result from the fact that the change in the number of composite particles of Comparative Example 7 and the resistance ratio ρr do not satisfy the numerical ranges of the physical properties (5) and (6).

Comparative Example 8
<Production of Composite Particles of Comparative Example 8>
As the composite particles of Comparative Example 8, the PMMA fine particles (average particle size: 8 m) synthesized in Synthesis Example 5 were attached to the silica core particles (average particle size: 290 m) synthesized in Synthesis Example 11 Composite particles produced by the same method as in Example 2-7 were used except that the surface treatment by MAPTMS was not performed.
Table 7 below shows a list of blending amounts of organic particles, inorganic particles, water, and HMDS in Comparative Example 8.

<Confirmation of physical properties of composite particles of Comparative Example 8>
Core particle average particle diameter, coefficient of variation thereof, fine particle average particle diameter / core particle average particle diameter, resistance ratio ρr, composite particle average particle diameter, relative dielectric constant, and physical properties of the composite particles of Comparative Example 8 Values are shown in Table 1, Table 2 and Table 7 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles of the composite particles of Comparative Example 8, the number change is 5% or more and less than 10%, the resistance ratio ρr is 1.5, and the physical properties (5) and It was confirmed that the numerical range of (6) was not satisfied.
<Evaluation of Composite Particles of Comparative Example 8>
In the composite particles of Comparative Example 8, the evaluation of the adhesion strength of the fine particles to the core particles and the fluidity evaluation due to the change in the degree of aggregation were both “C” evaluation, and the charge amount was −390, which was lower than the appropriate range.
Therefore, it was confirmed that the composite particles of Comparative Example 8 had low adhesion strength and lost fluidity. This evaluation result is considered to result from the fact that the change in the number of composite particles and the resistance ratio ρr of Comparative Example 8 do not satisfy the numerical ranges of the physical properties (5) and (6).

Comparative Example 9
<Production of Particles of Comparative Example 9>
As the particles of Comparative Example 9, the surface of the silica particles (average particle size: 110 nm) synthesized in Synthesis Example 9 was treated with hexamethyldisilazane (HMDS) in the same manner as in the hydrophobizing step of Example 2-1. Hydrophobized silica particles were used. The particles of Comparative Example 9 are not composite particles but inorganic particles, and the surface is not subjected to surface treatment with MAPTMS.
Table 7 below shows a list of blending amounts of organic particles, inorganic particles, water, and HMDS in Comparative Example 9.

<Confirmation of physical properties of particles of Comparative Example 9>
The average particle diameter of the core particles, the coefficient of variation thereof, the resistance ratio ρr, and the physical properties of the relative dielectric constant of the particles of Comparative Example 9 are shown in Tables 1 and 2 and Table 7 below.
Since the particles of Comparative Example 9 are not composite particles, they do not satisfy the numerical ranges of the above physical properties (3) and (6).
<Evaluation of Particles of Comparative Example 9>
The fluidity evaluation by the change in the degree of aggregation of the particles of Comparative Example 9 was “C” evaluation.
Therefore, it was confirmed that the particles of Comparative Example 9 lost fluidity. This evaluation result is considered to be due to the separation from the acrylic resin during the stirring and shaking by the tumbler mixer and the transition to the ferrite resin.

Comparative Example 10
<Production of Particles of Comparative Example 10>
As the particles of Comparative Example 10, the PMMA particles synthesized in Synthesis Example 1 (average particle size: 80 nm) were used as they were. The particles of Comparative Example 10 are not composite particles but organic particles, and the surface is not subjected to surface treatment with MAPTMS.
Table 7 below shows a list of blending amounts of organic particles, inorganic particles, and water in Comparative Example 10.

<Confirmation of physical properties of particles of Comparative Example 10>
The average particle diameter of the core particles, the coefficient of variation thereof, the resistance ratio ρr, and the physical properties of the relative dielectric constant of the particles of Comparative Example 10 are shown in Tables 1 and 2 and Table 7 below.
Since the particles of Comparative Example 10 are not composite particles, they do not satisfy the numerical ranges of the above physical properties (3) and (6).
<Evaluation of Particles of Comparative Example 10>
The fluidity evaluation by the change in the degree of aggregation of the particles of Comparative Example 10 was “D” evaluation.
Therefore, it was confirmed that the particles of Comparative Example 10 lost fluidity. This evaluation result is considered to be due to the separation from the acrylic resin during the stirring and shaking by the tumbler mixer and the transition to the ferrite resin.
Moreover, it was found that the charge amount was −480 and could not be controlled within an appropriate range.

Comparative Example 11
<Production of Composite Particles of Comparative Example 11>
As the composite particles of Comparative Example 11, PMMA core particles synthesized in Synthesis Example 1 (average particle size: 80 nm) and silica fine particles synthesized in Synthesis Example 6 (average particle size: 20 nm) were attached, and then the surface by MAPTMS Without treatment, the mixture was stirred and shaken for 30 minutes using a tumbler mixer, 200 g of water and 15 g of hexamethyldisilazane (HMDS) were added, and the mixture was stirred at room temperature for 30 minutes and further stirred at 60 ° C. for 4 hours. Thereafter, solid-liquid separation was performed, and the resulting precipitate was washed with methanol and then dried for 48 hours, and composite particles were used.
Table 7 below shows a list of blending amounts of organic particles, inorganic particles, water, and HMDS in Comparative Example 11.

<Confirmation of physical properties of composite particles of Comparative Example 11>
Core particle average particle diameter, coefficient of variation thereof, fine particle average particle diameter / core particle average particle diameter, resistance ratio ρr, composite particle average particle diameter, relative dielectric constant, and physical properties of the composite particles of Comparative Example 11 Values are shown in Table 1, Table 2 and Table 7 below.
As can be seen from the evaluation of the adhesion strength of the fine particles to the core particles, the composite particles of Comparative Example 11 have a number change of 10% or more and a resistance ratio ρr of 1.5, and the above physical properties (5) and (6) It was confirmed that the numerical range of was not satisfied.
<Evaluation of Composite Particle of Comparative Example 11>
In the composite particles of Comparative Example 11, the evaluation of the adhesion strength of the fine particles to the core particles and the fluidity evaluation due to the change in the degree of aggregation were both “D” evaluations, and the charge amount was −350, which was lower than the appropriate range.
Therefore, it was confirmed that the particles of Comparative Example 11 had low adhesion strength and lost fluidity. This evaluation result is considered to be due to the insufficient adhesion strength between the core particles and the fine particles in the production method such as the particles of Comparative Example 11.

  In the above-described embodiment, an example in which the composite particle of the present invention is applied to an external additive for toner is described. In the above-described embodiment, the composite particle of the present invention is a fine particle required for an external additive for toner. Although it was confirmed that the adhesion strength on core particles, good charge amount, and high fluidity could be secured, the composite particles of the present invention were used for powder coatings, water repellents, displays, anti-glare films (anti-reflection films), etc. Even when applied to other uses, the same effects as those shown in the above-described embodiments can be obtained, so that the present invention can also be suitably used in each of these uses.

In the above-described embodiment, the example in which the composite particle of the present invention includes one core particle mainly composed of one kind of organic material or inorganic material has been described. However, the present invention is not limited to this, One core particle may be, for example, an aggregate formed by combining particles mainly composed of a plurality of types of organic materials or inorganic materials indicated by C1, C2, C3... Cn in FIG. As described above, the composite particles of the present invention including the core particles which are aggregates formed by combining a plurality of types of particles can obtain the same effects as those shown in the above-described examples.
In the above-described embodiments, an example in which an acrylic resin is used as an organic material for forming organic core particles or organic fine particles has been described. However, the present invention is not limited to this, and polyester resin, epoxy resin, urethane is used. Even when other organic materials such as a resin are used, the same effects as those shown in the above-described embodiments can be obtained.
Further, in the above-described embodiment, the example in which silica is used as the inorganic material for forming the inorganic core particles or the inorganic fine particles has been described. However, the present invention is not limited thereto, and other inorganic materials are used. Even so, it is possible to obtain the same effects as those shown in the above-described embodiments.

A, C1, C2, C3... Cn core particle, B fine particle,
N inorganic material layer, D average particle diameter of composite particles,
DA core particle average particle size, DB fine particle average particle size,
X, Y strings.

Claims (12)

In composite particles comprising core particles and fine particles,
The main component of the core particle is one of an organic material and an inorganic material,
When the fine particles are present on the core particles and the main component of the core particles is an organic material, the main component of the fine particles is an inorganic material, and the main component of the core particles is an inorganic material. In some cases, the main component of the fine particles is an organic material,
The average particle diameter of the core particles is 80 nm or more and 300 nm or less, and the coefficient of variation of the average particle diameter of the core particles is 2% or more and 10% or less,
The average particle size of the fine particles is 5 nm or more and 30 nm or less, and the ratio of the average particle size of the fine particles to the average particle size of the core particles is 0.016 or more and 0.25 or less,
The composite particles have an average particle size of 90 nm or more and 350 nm or less,
A multiplier ratio β ₁ / β _{2 in} the volume resistance ρv = α ₁ × 10 ^β1 (Ω · cm) and surface resistance ρs = α ₂ × 10 ^β2 (Ω / cm ² ) of the composite particles is 0.7 or more. 4 or less,
The fine particles present on the core particles before and after irradiating the composite particle dispersion in which the composite particles are dispersed in water so as to be 1% by weight under the conditions of an output of 110 W and a frequency of 31 kHz for 30 minutes. Composite particles having a number change of 0.5% or more and 5% or less.   The composite particle according to claim 1, wherein a relative dielectric constant of the composite particle is 2 or more and 300 or less.   The composite particle according to claim 1 or 2, wherein a coverage of the fine particles on the surface of the core particle is 5% or more and 68% or less.   The composite particle according to any one of claims 1 to 3, wherein the core particle is formed from an organic material, and the fine particle is formed from an inorganic material.   The composite particle according to claim 4, further comprising fine particles formed from an organic material.   The composite particle according to claim 4 or 5, wherein the inorganic material is selected from the group consisting of silica, titania, cerium oxide, and strontium titanate.   The composite particle according to any one of claims 1 to 3, wherein the core particle is formed of an inorganic material, and the fine particle is formed of an organic material.   The composite particle according to claim 7, further comprising fine particles formed from an inorganic material.   The composite particle according to claim 7 or 8, wherein the inorganic material is selected from the group consisting of silica, titania, cerium oxide, and strontium titanate.   The composite particle according to any one of claims 1 to 9, wherein the composite particle includes an inorganic material layer that covers the surface of the core particle and the fine particle.   An external toner additive comprising the composite particles according to claim 1. In a method for producing composite particles comprising core particles and fine particles,
The fine particles adhere to the surface of the core particles from a dispersion liquid containing the core particles mainly composed of one of an organic material and an inorganic material and the fine particles mainly composed of either the organic material or the inorganic material. A particle adhering body forming step for forming the particle adhering body,
A silane coupling agent and a basic substance that binds to and interacts with one of the core particles and the fine particles are added to the dispersion in which the particle adhering body is formed, and the core particles are added. And a composite particle forming step of forming the composite particle having the fine particles immobilized on the surface thereof.

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