WO2018181669A1 - Composite particles and production method for composite particles - Google Patents

Abstract

Provided are composite particles that are each provided with a coating layer that is formed on the surface of an organic particle and that contains inorganic particles, and that can have improved heat resistance, etc. Also, provided is a composite particle production method for producing the composite particles while avoiding deformation or breaking of the organic particles. Composite particles (100) each have an organic particle (10) and a coating layer (20) which covers the surface of the organic particle (10), wherein the coating layer (20) is formed by having included therein a polymer of a metal alkoxide. The method for producing the composite particles comprises an inorganic particle production step for polymerizing the metal alkoxide to produce inorganic particles, and a coating step for depositing the inorganic particles around each organic particle to form a coating layer.

Description

Composite particle and composite particle manufacturing method

The present invention relates to composite particles and composite particle manufacturing methods.

Conventionally, organic particles containing organic substances have been widely used as toner components for printing presses, components contained in scattering agents added to films, and the like. Recently, organic particles containing semiconductor particles (so-called quantum dots) containing cadmium and selenium have been studied.

Further, as an example of other organic particles, Patent Document 1 proposes organic particles having silica particles attached to the surface. Specifically, in Patent Document 1, stress is applied to silica particles having a primary particle volume average particle size of 200 nm or less and having a predetermined functional group, and organic particles larger than the volume average particle size of the silica particles. Silica-coated organic particles obtained by mixing while adding and adhering the silica particles to the surface of the organic particles are disclosed. Patent Document 1 describes that the above adhesion is performed by applying stress between organic particles and silica particles by stirring and the like. Patent Document 1 describes that the agitation is performed by high-speed rotation capable of applying a stress greater than the force that plastically deforms the surface of the organic particles between the particles.

Japanese Unexamined Patent Publication No. 2016-124729

By the way, in general, organic particles are easy to manufacture and handle, but there is room for improvement in terms of heat resistance, durability, and acid resistance (hereinafter also referred to as heat resistance) compared to inorganic particles. was there. According to the disclosure of Patent Document 1 described above, an improvement in heat resistance and the like of the particles is expected by attaching an inorganic substance to the surface of the organic particles as compared to before coating. However, in such a case, the silica particles collide with and adhere to the surface of the organic particles to such an extent that the form of the organic particles can be changed.

The present invention has been made in view of the above problems. That is, the present invention provides a composite particle that includes a coating layer containing an inorganic substance on the surface of the organic particle, and that can improve heat resistance and the like, provides a composition containing the composite particle, Provided is a composite particle manufacturing method for manufacturing the composite particles while avoiding destruction.

The composite particles of the present invention are characterized in that they have organic particles and a coating layer that covers the surface of the organic particles, and the coating layer includes a polymer of metal alkoxide.

The composition of the present invention includes the composite particles of the present invention.

Moreover, the composite particle manufacturing method of the present invention includes an inorganic particle preparation step in which metal alkoxide is polymerized to prepare inorganic particles, and a coating step in which the inorganic particles are deposited around the organic particles to form a coating layer. It is characterized by.

Since the composite particles of the present invention are provided with a coating layer configured to have a metal alkoxide polymer on the surface of the organic particles, heat resistance and the like can be improved as compared with the case where the coating layer is not provided.

According to the composition of this invention, the outstanding property which enjoyed the effect of the composite particle of this invention is shown.
Moreover, according to the manufacturing method of this invention, the composite particle provided with the coating layer containing an inorganic particle can be manufactured, avoiding a deformation | transformation and destruction of an organic particle.

It is a schematic diagram of the composite particle of this invention. It is a conceptual diagram of the inorganic particle in the composite particle of this invention. 2 is an electron micrograph obtained by observing the peripheral surface of the composite particles of Example 1. FIG. 2 is an electron micrograph of the cut surface of the composite particle of Example 1 observed. 4 is an electron micrograph of the cut surface of organic particles A of Comparative Example 1 observed. 6 is an electron micrograph of the peripheral surface of Example 5 observed.

[Composite particles]
Below, the composite particle 100 of this invention is demonstrated using FIG. 1, FIG. FIG. 1 is a schematic view showing an embodiment of the composite particle 100 of the present invention, and a part of the coating layer 20 is not shown for explaining the organic particle 10. FIG. 2 is a conceptual diagram of the inorganic particles 30 in the composite particle 100 and shows the inorganic particles 30 that are hydrolyzed polycondensation products of tetraethoxysilane. The composite particle 100 of the present invention has an organic particle 10 and a coating layer 20 that covers the surface of the organic particle 10. The coating layer 20 is configured to have a metal alkoxide polymer. When the composite particle 100 includes the coating layer 20, heat resistance and the like can be improved as compared to the organic particle 10 that does not have the coating layer 20.
In addition, in the following description, the preferable numerical range of this invention may be shown suitably. In this case, a preferable range, a more preferable range, and a particularly preferable range regarding the upper limit and the lower limit of the numerical range can be determined from all combinations of the upper limit and the lower limit.
In the present invention, the average particle diameter of the organic particles 10 or the inorganic particles 30 is 100 particles randomly selected from a microscopic observation photograph taken in a scanning electron microscope observation (magnification about 50,000 times). It means an arithmetic average value calculated by actually measuring the particle diameter and using the obtained actual measurement value. The average particle diameter of Examples described later was also obtained in the same manner.

In the prior art, regarding organic particles whose surfaces are coated with inorganic particles, it has only been disclosed that silica particles are attached to the surface of organic particles by stress as in the above-described prior art 1. In contrast, according to the present invention, the coating layer is configured by including a metal alkoxide polymer, and the coating layer 20 can be provided without depending on physical stress.

In the following description, an example in which the coating layer 20 includes a plurality of inorganic particles 30 composed of a polymer of metal alkoxide will be described. However, this does not limit the present invention in any way. The purpose of the present invention is to provide composite particles whose heat resistance and the like can be improved by providing a coating layer containing an inorganic substance around the organic particles. Therefore, the coating layer in the present invention is a deposition layer formed by depositing a particulate inorganic material, a coating layer formed by forming a non-particulate inorganic material into a film, or a part of which is composed of a particulate inorganic material and another part. Includes an embodiment composed of a non-particulate inorganic substance. Whether or not the coating layer 20 contains particulate inorganic substances (that is, inorganic particles) is determined based on observation at a magnification of about 50,000 times using a scanning electron microscope, or determined from the method for manufacturing the composite particles 100. Is possible. For example, the coating layer 20 in the composite particle 100 manufactured by a manufacturing method using a Stover method to be described later is presumed that the coating layer 20 contains a particulate inorganic substance regardless of observation with a scanning electron microscope. In addition, the inorganic substance here contains both the compound which consists only of an inorganic component, or the compound which mainly consists of an inorganic component including an organic component.
Hereinafter, the composite particle 100 will be described in detail. The description regarding the inorganic substance which comprises the inorganic particle 30 in the following can be referred as description of the inorganic substance contained in the coating layer formed into a film suitably.

(Coating layer)
The constituent components of the coating layer 20 are mainly inorganic particles 30. However, the above constituent components may contain other components other than the inorganic particles 30 without departing from the gist of the present invention. Here, the constituent component being mainly the inorganic particles 30 means that the inorganic particles 30 are 50% by mass or more when the coating layer 20 at the time of drying is 100% by mass. From the viewpoint of improving heat resistance and the like, the inorganic particles 30 described above are preferably 70% by mass or more, and more preferably 90% by mass or more. According to the composite particle manufacturing method of the present invention, which will be described later, the coating layer 20 can be substantially composed of only the inorganic particles 30.

The coating layer 20 may be a single layer or may be configured in multiple layers.
The multi-layer coating layer 20 is configured by laminating two or more layers on the peripheral surface of the organic particle 10. The multilayer here includes a case where the critical plane between adjacent layers is clear and a case where the critical plane is unclear. For example, by performing the coating process for producing the coating layer 20 a plurality of times, a multilayer coating layer 20 in which the same number of layers as the number of times of the coating process are stacked can be configured. The thickness of the cover layer 20 can be significantly increased by being configured in multiple layers. As a result, the heat resistance and the like of the composite particle 100 can be significantly improved.
As one of the preferable aspects regarding the multilayer coating layer 20, the coating layer 20 is comprised from the inorganic particle 30, The average particle diameter of the inorganic particle 30 which comprises one layer in the coating layer 20, and said one layer The aspect from which the average particle diameter of the inorganic particle 30 which comprises another adjacent layer differs is mentioned. In the above aspect, the adhesion between the one layer and the other layer is improved. From such a viewpoint, the coating layer 20 has one layer and another layer adjacent to the side opposite to the organic particle 10 of the one layer, and the average particle diameter of the inorganic particles 30 constituting the one layer. However, an aspect larger than the average particle diameter of the inorganic particles 30 constituting the other layer is more preferable. According to this aspect, the other layer constituted by the relatively small particle size inorganic particles 30 is laminated on the outer periphery of the one layer constituted by the relatively large particle size inorganic particles 30. Therefore, it is possible to fill the gaps between the large-sized particles exposed on the outer surface side of the one layer with the small-sized inorganic particles 30. As a result, a dense coating layer 20 is formed. In addition, in the multilayer coating layer 20 composed of the inorganic particles 30, the method for making the average particle diameter of the inorganic particles 30 different for each layer is not particularly limited. For example, it can be carried out by changing any coating conditions such as the concentration of the material used, the number of stirring, the stirring speed, or the temperature for each repeated coating process.
Moreover, in the coating layer 20 which is a multilayer, the adjacent layer may be comprised from the same kind of material, and may be comprised from a different material. Here, being composed of different materials means that the compositions of materials constituting one layer and another layer adjacent thereto are different from each other.

The constituent component of the inorganic particles 30 is mainly a polymer of metal alkoxide. However, in the range which does not deviate from the main point of this invention, other components other than the polymer of a metal alkoxide may be included. Here, that the constituent component is mainly a polymer of metal alkoxide means that the metal alkoxide is 50% by mass or more when the inorganic particles 30 at the time of drying are 100% by mass. From the viewpoint of satisfactory formation of the coating layer 20, the metal alkoxide described above is preferably 70% by mass or more, and more preferably 90% by mass or more.

In the present invention, the metal alkoxide is a compound represented by the general formula M (OR) _n or a modified product thereof. Here, M is a metal, n is an oxidation number of M, and R is an alkyl group. Examples of the metal represented by M include silicon, magnesium, germanium, vanadium, and the like.

The polymer of the metal alkoxide is a compound obtained by polymerizing the metal alkoxide, and the polymerization method is not particularly limited. From the viewpoint of easily obtaining good effects such as heat resistance, the compound constituting the inorganic particles 30 of the present invention is preferably a polycondensate of metal alkoxide, and a polycondensate of hydrolyzate of metal alkoxide. It is more preferable that Metal alkoxide causes steric hindrance due to its structure. Therefore, the metal alkoxide may have low reactivity of the condensation polymerization reaction. In such a case, it is preferable to first produce a hydrolyzate of metal alkoxide and then subject the hydrolyzate to a condensation polymerization reaction. Thereby, a polymer of a metal alkoxide having a high density and three-dimensional polymerization and high heat resistance can be obtained. A three-dimensional polymer of metal alkoxide is preferable as a constituent component of the inorganic particles 30. Compared with a linear polymer, the three-dimensional polymer can easily obtain the inorganic particles 30 having a nano-sized particle diameter and can easily form the coating layer 20.

Examples of the metal alkoxide include, but are not limited to, alkoxysilane, alkoxymagnesium, alkoxygermanium, alkoxyvanadium, and the like. Among these, as the metal alkoxide, alkoxysilane is preferable as a material for the polymer constituting the inorganic particles 30 of the present invention. Among the metal alkoxides, alkoxysilanes can easily form inorganic particles 30 having a nano-size particle size and made of a three-dimensionally bonded polymer. Therefore, the alkoxysilane can constitute a desirable coating layer 20. For example, by performing the Stover method, it is possible to produce inorganic particles 30 that are nano-sized and have a relatively uniform particle size from alkoxysilane.

As the alkoxysilane, tetraethoxysilane or tetramethoxysilane is preferable. With these hydrolytic condensation polymers, inorganic particles 30 having a nano-sized particle size and made of a three-dimensionally bonded polymer can be satisfactorily constituted.

Tetraethoxysilane and tetramethoxysilane are generally known to be difficult to polycondensate due to steric hindrance. However, by performing the so-called Stover method, a compound preferable as the inorganic particle 30 in the present invention can be easily produced. The Stover method will be described later.

For example, particles obtained by hydrolytic condensation polymerization of tetraethoxysilane are constituted by three-dimensional bonds including a bond of Si—O—Si as shown in FIG.

The average particle diameter of the inorganic particles 30 is not particularly limited. For example, the lower limit of the average particle diameter of the inorganic particles 30 is preferably 3 nm or more, more preferably 5 nm or more, and further preferably 10 nm or more. preferable. Further, the upper limit of the average particle size of the inorganic particles 30 is preferably 150 nm or less, more preferably 120 nm or less, and further preferably 90 nm or less. The nano-sized inorganic particles 30 in the above range are suitable for forming the coating layer 20 by covering the surface of the organic particles 10 having an average particle diameter of about 0.01 μm to 30 μm without any gap.

The coating amount of the coating layer 20 is not particularly limited. In terms of significantly improving the heat resistance and the like of the composite particle 100, when the composite particle 100 is 100% by mass, the mass of the coating layer 20 is preferably 10% by mass to 70% by mass, and 20% by mass. It is more preferable that the content is not less than 60% and not more than 60% by mass. When the coating amount of the coating layer 20 is equal to or greater than the above numerical range, a remarkable improvement effect such as heat resistance is easily obtained. Moreover, when the coating amount is equal to or less than the upper limit of the above numerical range, the original function and effect of the organic particles 10 are easily exhibited satisfactorily. The mass ratio of the coating layer 20 to the composite particle 100 described above is that the mass W1 of the composite particle 100 is measured, and then the composite particle 100 is subjected to a thermogravimetric / differential thermal measurement test (simultaneous differential thermal-thermogravimetric measurement; TG-DTA). ), The mass W2 of the residue after the end of combustion is measured, and the percentage (%) of W2 with respect to W1 is calculated.

(Organic particles)
Next, the organic particles 10 will be described. The organic particle 10 is a granular compound mainly composed of an arbitrary organic substance. Although the organic particles 10 may not have sufficient heat resistance or the like as compared with the inorganic material, the composite particles 100 of the present invention include the coating layer 20, so that the heat resistance and the like are improved compared to the organic particles 10 alone. In addition, the organic particle 10 in the present invention includes any form of a particle substantially made only of an organic substance or a particle mainly containing an organic substance and containing an inorganic substance. In the present invention, the organic substance includes a polymerizable organic compound, an already polymerized organic compound, a polymerizable organic substance that is a mixture thereof, and a non-polymerizable organic substance mainly composed of a non-polymerizable organic compound.

For example, the organic particles 10 are configured to include a (meth) acrylic resin. The (meth) acrylic resin is an example of a polymerizable organic material. Organic particles 10 composed of (meth) acrylic resins are used in a wide range of technical fields. Since the composite particles 100 in which the coating layer 20 is provided on the organic particles 10 made of (meth) acrylic resin can be improved in heat resistance and the like, it can be used in more severe use environments and new technical fields. In the present specification, (meth) acrylic resin means acrylic resin or methacrylic resin, and (meth) acrylate means acrylate or methacrylate.

The acrylic resin or the methacrylic resin is a polymer obtained by polymerization using one or more of (meth) acrylate monofunctional monomer, bifunctional monomer, or polyfunctional monomer. Especially, the aspect in which a bifunctional or polyfunctional (meth) acrylic-type monomer is contained as a material which comprises the organic particle 10 is preferable. In the above aspect, the inorganic particles 30 are easily deposited on the surface of the organic particles 10. Thereby, the coating layer 20 that sufficiently contributes to improvement in heat resistance and the like is easily formed. In the present invention, the term “depositing the inorganic particles 30 on the surface of the organic particles 10” means that the inorganic particles 30 having an average particle size smaller than the average particle size of the organic particles 10 are physically collided with the surface of the organic particles 10. It means that it adheres regardless of the stress. The adhesion can be realized by a chemical bond between the organic particles 10 and the inorganic particles 30 or an intermolecular attractive force, a chemical bond between the inorganic particles 30 or an intermolecular attractive force, or a combination thereof.

Examples of the monofunctional (meth) acrylic monomer include stearyl (meth) acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, and tridecyl (meth) acrylate.
Examples of the bifunctional (meth) acrylic monomer include di (meth) acrylates such as tricyclodecane dimethanol di (meth) acrylate or polypropylene glycol di (meth) acrylate.

The polyfunctional (meth) acrylate monomer is a (meth) acrylate monomer containing three or more functional groups, and the number of functional groups depends on the stress caused by the collision. From the viewpoint of good deposition, it is preferably trifunctional or higher, more preferably tetrafunctional or higher. Examples of the polyfunctional (meth) acrylate resin include polyester acrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and the like.

From the viewpoint of easily depositing the inorganic particles 30 on the surface of the organic particles 10 to easily form the coating layer 20, the organic particles 10 preferably contain a compound having a polar group. Here, the polar group means a reactive group capable of imparting polarity to the organic particles 10. Examples of the reactive group include an electron-withdrawing group such as a carboxyl group or an electron-donating group such as an amino group. The organic particle 10 containing a compound having a polar group is, for example, an embodiment in which a compound having an arbitrary polar group is bonded to a base resin constituting the organic particle 10 or a compound having a polar group inside the organic particle 10 Including an embodiment in which is simply buried. In the composite particle 100, the polar group includes a state before being bonded to another reactive group, or a state in which the polar group is bonded to another reactive group.

Examples of the compound having a polar group include carboxylic acid-containing acrylates such as carboxy-polycaprolactone monoacrylate, epoxy group-containing acrylates such as glycidyl methacrylate, and hydroxyl group-containing acrylates such as 4-hydroxybutyl acrylate. Among these, from the viewpoint that the coating layer 20 can be formed by satisfactorily bonding the inorganic particles 30 and the carboxyl group in the Stover method described later, a carboxylic acid-containing acrylate is preferable as the compound having a polar group.

As a preferred embodiment of the compound having a polar group described above, a silane coupling agent can be exemplified. The silane coupling agent has two or more different reactive groups in the molecule. Therefore, the silane coupling agent binds to the compound constituting the organic particle 10 in one reactive group and binds to the inorganic substance constituting the coating layer 20 in the other reactive group. By the bonding, the coating layer 20 can be favorably formed on the outer periphery of the organic particle 10. That is, since the organic particles 10 contain a silane coupling agent, the organic particles 10 and the inorganic particles 30 are chemically bonded sufficiently by the silane coupling agent. As a result, the coating layer 20 is formed satisfactorily. Here, the silane coupling agent means a compound containing silane and having two types of functional groups having different reactivity in one molecule. Examples of the silane coupling agent include a first functional group that can be chemically bonded to an inorganic material (for example, methoxy group or ethoxy group) and a second functional group that can be chemically bonded to an organic material (for example, vinyl group, epoxy). And a group having an amino group, an amino group, a (meth) acryl group, a styryl group, or a mercapto group) are preferable. Among these, it is preferable to select a silane coupling agent having the same functional group as that of the monomer constituting the organic particles 10. For example, when the monomer used to constitute the organic particles 10 is a (meth) acrylate monomer, a silane coupling agent having a (meth) acryl group as one functional group is suitable.

Specific examples of the silane coupling agent include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane. Methacrylic silane coupling agent with methacrylic group; Acrylic silane coupling agent with acrylic group such as 3-acryloxypropyltrimethoxysilane; Vinyl-based silane with vinyl group such as vinyltrimethoxysilane or vinyltriethoxysilane Coupling agent; 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glyci Epoxy-based silane coupling agents having an epoxy group such as xylpropylmethyldiethoxysilane or 3-glycidoxypropyltriethoxysilane; styryl-based silane coupling agents having a styryl group such as p-styryltrimethoxysilane; N -2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3 -Triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane or N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane Amino groups such as hydrochloride Amino-based silane coupling agent comprising; or 3-mercaptopropyl methyl dimethoxy silane, or 3-mercaptopropyltrimethoxysilane mercapto silane coupling agent comprising a mercapto group such as and the like.
In the silane coupling agent described above, from the viewpoint of easy bonding with the organic particles 10, a vinyl silane coupling agent containing a double bond in the functional group, a styryl silane coupling agent, and a methacrylic silane coupling agent. Or, an acrylic silane coupling agent is preferable, and a methacrylic silane coupling agent or an acrylic silane coupling agent is more preferable.

The organic particles 10 are made of an organic material such as a (meth) acrylic resin as described above, but may optionally contain other materials. Examples of the other materials include various additives for producing the organic particles 10 or functional materials for imparting a specific function to the organic particles 10. That is, this invention includes the aspect in which the organic particle 10 contains a functional material.
The functional material for imparting a specific function to the organic particles 10 is contained, and the coating layer 20 is provided on the surface of the organic particles 10, whereby the heat resistance of the organic particles 10 to which the specific functions are imparted. Etc. are improved. In this case, the organic substance itself that constitutes the organic particles 10 has an aspect in which only a functional material is supported, an aspect in which the organic substance itself is expected to have some function, or some function in relation to the organic substance and the functional material. Any of the modes to be exhibited may be used.

Here, the functional material for imparting a specific function to the organic particles 10 is not particularly limited. Examples of the functional material include a semiconductor material such as an organic semiconductor material or an inorganic semiconductor material, a metal or metal oxide such as a zirconia material, a silica material or an alumina material, a conductive material such as an organic conductive material or a metal conductive material, Examples include ultraviolet absorbers (UVA) and cellulose nanofibers (CNF). In particular, when the functional material is a material with relatively low heat resistance, or when a high temperature is expected in the use environment, the functional material is contained in the organic particles 10 in the composite particle 100. It is preferable. This is because the effect of improving the heat resistance of the functional material itself is substantially exhibited. The shape, content, or size of the functional material is not particularly limited as long as it is contained in the organic particles. Examples of the shape of the functional material include, but are not limited to, a particle shape, a powder shape, and a fiber shape.

Examples of the functional material contained in the organic particles 10 include a particulate semiconductor material (hereinafter referred to as semiconductor particles). For example, the organic particles 10 may include one or more semiconductor particles.
The term “semiconductor particles” as used herein refers to a particulate material having semiconductor properties. The semiconductor particles include so-called quantum dots (also referred to as Quantum dots; QD), which are fluorescent fine particles having a nano-size particle size. A quantum dot is a material with excellent color rendering properties that emits bright fluorescence having a specific wavelength depending on the particle diameter when an excitation wavelength such as ultraviolet rays is applied. In recent years, quantum dots have been tried to be used in the field of luminescent materials in the technical field of display devices and the like. The quantum dots are generally fine particles having a particle size of several nm, and there is a possibility that aggregation occurs when the quantum dots are filled into the carrier as they are. On the other hand, the aggregation of quantum dots can be avoided with the fluorescent composite particles 100 in which the coating layer 20 is provided on the organic particles 10 containing one or more quantum dots. In addition, since the composite particles 100 are excellent in heat resistance, the fluorescent composite particles 100 described above can provide a fluorescent material having an excellent effect that can withstand repeated ultraviolet irradiation and heating. The fluorescent composite particle 100 can increase the lifetime of the quantum dots. The fluorescent composite particle 100 described above is suitable as a fluorescent material used in a display device. However, the fluorescent composite particle 100 can be used in other technical fields (for example, using a fluorescent probe in a living body), and the above-described excellent effects can be desirably exhibited in each technical field.

The average particle diameter of the organic particles 10 is not particularly limited, but is preferably 0.01 μm or more and 30 μm or less, and more preferably 0.5 μm or more and 10 μm or less. The average particle size is a suitable size as organic particles used in various technical fields from the viewpoints of form retention, ease of production, dispersibility when added to any material, and the like. It is particularly preferable that the average particle size of the inorganic particles 30 deposited on the surface of the organic particles 10 having the average particle size in the above range is in the numerical range described above. The inorganic particles 30 having an average particle diameter in the above range are easily deposited on the peripheral surface of the organic particles 10 having the average particle diameter, and can easily form the coating layer 20 that can cover substantially the entire peripheral surface.

In the composite particle 100, the average particle diameter of the organic particles 10 is 0.01 μm or more and 30 μm or less, and the average film thickness of the coating layer 20 is 5 nm or more and 400 nm or less, which is a preferable example in this embodiment. By covering the peripheral surface of the organic particles 10 exhibiting an average particle size in an appropriate range with the coating layer 20 that is an inorganic material having a film thickness in the numerical range, the organic particles 10 can sufficiently exhibit their original functions, Heat resistance etc. can be improved favorably. In addition, the average film thickness of the coating layer 20 described above is obtained by observing the cut surfaces of five randomly selected composite particles 100 in a scanning electron micrograph (magnification 50,000 times), and covering each composite particle 100 with a coating. In the layer 20, three points are selected at equal intervals in the circumferential direction, the thickness is measured, and an average value obtained by arithmetically averaging all the measured values is indicated.

[Composite particle production method]
Next, the composite particle manufacturing method of the present invention (hereinafter also referred to as the manufacturing method of the present invention) will be described. The production method of the present invention described below is a preferred embodiment of the production method of the composite particles of the present invention. However, within the scope not departing from the gist of the present invention, the production method of the composite particles includes a part of the following contents. May be changed as appropriate, or additional steps may be performed. According to the production method of the present invention described below, composite particles including a coating layer containing inorganic particles can be produced. As a different production method of the composite particle of the present invention, a composite particle including a coating layer formed by forming an inorganic substance whose particle shape is not specified around an organic particle can be produced by a production method including a general sol-gel method. It is. In addition, about the composite particle of this invention and each material which comprises this, since the description regarding the composite particle 100 mentioned above can be referred, it omits suitably in the following description.

The manufacturing method of the present invention includes an inorganic particle preparation step and a coating step. The inorganic particle preparation step is a step of preparing inorganic particles by polymerizing metal alkoxide. The coating step is a step of forming a coating layer by depositing the inorganic particles produced in the inorganic particle production step around the organic particles. The production method of the present invention can produce composite particles comprising organic particles coated with an inorganic substance without deforming or destroying the shape of the organic particles that serve as the core. Below, the aspect also including the organic particle preparation process which produces the organic particle used in a coating process is demonstrated.

(Organic particle production process)
In the organic particle production step, the organic particles are prepared by a conventionally known method (for example, suspension polymerization or emulsion polymerization) capable of producing organic particles having a desired average particle diameter. From the viewpoint that it is easy to prepare organic particles having a desired average particle size range, and to easily include an optional material such as a quantum dot inside the particles as needed, an organic particle production step for producing organic particles by suspension polymerization Is preferably implemented.
More specifically, in the organic particle preparation step, an organic material such as an acrylic monomer is added to water or an aqueous solvent, suspended by mechanical stirring to form suspended particles, and heat energy or light energy is added. As a result, the organic material constituting the suspended particles is polymerized to produce organic particles. The stirring conditions during suspension may be appropriately determined with reference to a known suspension polymerization method. For example, the stirring may be performed at a rotational speed of 2000 rpm to 20000 rpm for 1 minute to 1 hour. During the polymerization reaction, stirring may be performed so that suspended particles can be dispersed in water or an aqueous solvent. The stirring is desirably about 100 rpm to 500 rpm. If necessary, a polymerization initiator such as a radical generator or a suspension stabilizer such as polyvinyl alcohol may be added together with the organic material. When preparing an organic particle containing an arbitrary material that exhibits a desired function such as a quantum dot, suspension polymerization may be performed using a mixed liquid containing the arbitrary material and an organic material for constituting the organic particle. Thereby, the organic particle which hold | maintained the said arbitrary material inside can be prepared. For example, when preparing organic particles containing quantum dots by suspension polymerization, it is possible to prepare organic particles containing one or more quantum dots by adjusting the amount of quantum dots added to the mixture. It is.

The method for imparting a polar group to the organic particles 10 is not particularly limited. For example, organic particles containing a compound having a polar group by suspension polymerization using a monomer and a compound having a polar group constituting the organic particle 10 are used. It can be easily manufactured.

For example, by using the monomer and the silane coupling agent that constitute the organic particle 10 and suspension polymerization, one reactive group of the silane coupling agent and the monomer are combined with each other, and another reaction of the silane coupling agent is performed. Organic particles 10 having a group (polar group) can be easily produced.

In addition, in the manufacturing method of this invention, instead of implementing the organic particle preparation process mentioned above, you may prepare commercially available organic particle suitably and may use it for the coating process mentioned later.

(Inorganic particle production process)
The inorganic particle production step is performed by appropriately selecting from known methods capable of producing particles having a desired average particle diameter. For example, it is preferable that the inorganic particle preparation step includes implementation of a sol-gel method. The sol-gel method in the present embodiment means a method for producing inorganic particles by using a metal alkoxide solution, hydrolyzing and polycondensing the metal alkoxide. By carrying out the sol-gel method, inorganic particles having a metal alkoxide polymer having an average particle size of nano-size and a relatively uniform particle size can be easily produced. Further, as will be described later, when the inorganic particle preparation step and the coating step are performed in the presence of organic particles, if the sol-gel method is used, the reaction is performed at a temperature lower than the temperature at which the organic particles are burned or decomposed. Particles can be prepared and composite particles can be manufactured in a series of steps.

For example, when the metal alkoxide is alkoxysilane, the Stover method is preferably performed in the inorganic particle manufacturing step. In the present invention, the Stover method is a kind of the sol-gel method described above, and a method for hydrolyzing an alkoxysilane in a large amount of a basic solvent and then subjecting it to condensation polymerization to provide a particulate condensation polymer. Point to. More specifically, for example, tetraethoxysilane is added to a basic solvent to which ethanol or the like is added, and gently stirred at a rotation speed of 100 rpm to 1500 rpm for 2 hours to 48 hours. At this time, the mixture is preferably stirred at a liquid temperature of 25 ° C. or lower. Regarding the rotational speed, the outermost peripheral speed is preferably in the range of 0.1 m / s to 10 m / s. For example, a magnetic stirrer or the like may be used and gently stirred. Thereby, the hydrolysis reaction of the following formula 1 occurs, and the reaction is promoted, whereby all the alkoxy groups of tetraethoxysilane are hydrolyzed, and finally Si (OH) ₄ is obtained. When the stirring is further continued, as shown in the following formula 2, a polycondensation reaction occurs between two molecules of Si (OH) ₄ , and this is accelerated to obtain a hydrolytic polycondensation product of alkoxysilane.

[Chemical 1]
_n Si (OC ₂ H ₅ ) ₄ + _n H ₂ 0
→ _n Si (OH) (OC ₂ H ₅ ) ₃ + _n C ₂ H ₅ OH (Formula 1)

[Chemical formula 2]
Si (OH) ₄ + Si (OH) ₄ → (OH) ₃ Si—O—Si (OH) ₃ (Formula 2)

Alkoxysilane can be hydrolyzed in an acidic solvent and then subjected to polycondensation, but according to this, the obtained hydrolytic polycondensate has a structure close to a straight chain. On the other hand, by hydrolyzing and polycondensating alkoxysilane in a basic solvent, a polymer with high density and advanced three-dimensionality can be obtained. From the viewpoint of forming the coating layer with inorganic particles and thereby improving the heat resistance and the like of the organic particles serving as the core, the inorganic particles are preferably composed of a polymer that has become three-dimensional. Therefore, it is preferable to carry out the Stover method in which the reaction is promoted in a basic solvent in the inorganic particle preparation step.

(Coating process)
The coating step is carried out by gently stirring a mixed liquid in which the organic particles produced in the organic particle production step and the inorganic particles produced in the inorganic particle production step are added to an arbitrary liquid. By carrying out the coating step, it is possible to deposit inorganic particles on the surface of the organic particles without deforming the shape of the organic particles and to coat the organic particles with the inorganic particles. The stirring condition of the mixed liquid is appropriately determined within a range in which there is no fear that the organic particles and the inorganic particles collide and at least one of the shapes is deformed. For example, the above mixed solution may be stirred at a rotation speed of 100 rpm to 1500 rpm in a range of 2 hours to 48 hours, preferably at a liquid temperature of 25 ° C. or less. The agitation time described above is a substantially agitating time, and may be continuously agitated for a predetermined time or may be agitated intermittently. As said arbitrary liquid, alcohol, such as ethanol, is mentioned, for example. In the case where the coating step is carried out continuously from the inorganic particle production step, the above arbitrary liquid in the coating step may be an alcohol and a basic solvent in the inorganic particle production step.

As described above, when it is desired to form a coating layer more satisfactorily under mild stirring conditions, it is preferable to use organic particles containing a compound having a polar group. This is because the inorganic particles can be favorably deposited on the surface of the organic particles.

The coating layer formed on the surface of the organic particles by performing the coating process preferably has a large thickness from the viewpoint of improving heat resistance and the like. In other words, it is preferable that the amount of inorganic particles deposited on the organic particles is large. As a desirable method for increasing the thickness of the coating layer, a method of repeating the coating step a plurality of times can be mentioned. That is, using a mixed solution containing inorganic particles at an appropriate concentration, a coating step is performed to produce composite particles, and the composite particles are taken out from the reaction vessel in which the coating step has been performed. And the liquid mixture with which the taken-out said composite particle and the inorganic particle produced in the said inorganic particle preparation process or the inorganic particle preparation raw material were added is stirred like the above. When the coating step is repeated in this way, composite particles in which a coating layer in which inorganic particles are densely deposited are formed in multiple layers can be produced. The number of repetitions of the coating step is not particularly limited. For example, the thickness of the coating layer can be increased efficiently by performing the coating step in the range of 2 to 10 times. Further, as a different method for increasing the thickness of the coating layer, it is also effective to sufficiently increase the concentration of alkoxysilane or basic catalyst used as the inorganic particle raw material used in the coating step.

That is, regarding the manufacturing method of the present invention in which the coating process is repeated, more specifically, the coating process includes a first coating process and a second coating process.
The first coating step is a step in which a mixed liquid containing the inorganic particles and the organic particles is added to a reaction vessel and stirred to produce composite particles including a single coating layer. An inorganic particle production raw material may be used instead of the inorganic particles, and the inorganic particle production process and the coating process may be performed continuously.
In the second coating step, after completion of the first coating step, the composite particles having a single layer coating layer are taken out from the reaction vessel in the first coating step, and then the single layer coating layer is placed in the reaction vessel in the second coating step. Is a step of adding a mixed liquid containing composite particles and inorganic particles (or inorganic particle production raw materials) and stirring them to produce composite particles having a multilayer coating layer. After completion of the first coating step, the composite particles taken out from the reaction layer may be dried as necessary, and then added to the reaction vessel in the second coating step.
The reaction tanks in the first coating step and the second coating step may be used together or may be different. When the reactor is also used, after the first coating process is completed, drain the used mixed solution used in the first coating process from the reaction tank and add a new mixed solution for the second coating process. Or it is good to add a necessary material to the said used liquid mixture, and to adjust for a 2nd coating process.
In the first coating step and the second coating step, the coating conditions and the materials used may be the same or different. By changing the coating conditions in the first coating step and the second coating step, the average particle diameter of the inorganic particles constituting the first layer formed in the first coating step and the second coating step are formed. It is possible to make the average particle diameter of the inorganic particles constituting the second layer different.
In the above description, the first coating process and the second coating process have been described for the coating process that is repeated a plurality of times, but the third coating process, the fourth coating process, and any number of coating processes may be repeated. it can. Each coating process after the third coating process can be carried out in the same manner as the second coating process except that the composite particles having a multilayer coating layer are taken out from the reaction vessel in the immediately preceding coating process.

By the coating step, composite particles having a coating layer of inorganic particles on the surface of the organic particles can be produced. After the coating step, the produced composite particles may be isolated by appropriately performing a centrifugation step, a washing step, and the like.

In the production method of the present invention, the order in which the organic particle production process, the inorganic particle production process, and the coating process described above are performed is not particularly limited. Each process may be implemented independently, may be implemented continuously, and may overlap with the process in which a part of process is followed. By carrying out the inorganic particle preparation step and the coating step continuously in the same liquid phase, the inorganic particle preparation step and the coating step may be carried out continuously. Thereby, the manufacturing method of the present invention can shorten the manufacturing process.

As a more specific step of the production method of the present invention, for example, organic particles prepared in advance and an alcohol such as ethanol having a small carbon number (preferably an alcohol having 3 or less carbon atoms) are mixed, and then ammonia water or the like. The basic solvent is added and stirred, and alkoxysilane such as tetraethoxysilane is further added and stirred under predetermined conditions. As a result, in the presence of organic particles, an inorganic particle preparation process is carried out in which hydrolysis and polycondensation of alkoxysilane proceeds, and a coating process in which the prepared inorganic particles are deposited on the surface of the organic particles is continuously executed. can do. Such an embodiment can efficiently produce composite particles.

As a different aspect, the production method of the present invention may prepare inorganic particles and organic particles obtained by polymerizing metal alkoxide, for example, by purchasing a commercially available product. The production method of the present invention includes a method for producing composite particles, characterized in that, using these, a coating step is performed in which the inorganic particles are deposited around the organic particles to form a coating layer. In such an embodiment, for example, organic particles and inorganic particles are added to an appropriate liquid (for example, alcohol such as ethanol), a basic solvent or an acidic solvent is added as appropriate, and the stirring conditions shown in the coating step described above are used. It is carried out by stirring.

According to the production method of the present invention described above, it is possible to provide composite particles including a coating layer containing inorganic particles while avoiding deformation and destruction of organic particles serving as a core.

[Composition]
The present invention includes a composition comprising the composite particle of the present invention described above. The composition of the present invention includes organic particles and a composite particle that includes a coating layer that covers the surface of the organic particle, and the coating layer includes a metal alkoxide polymer. Therefore, the composition of the present invention can avoid impairing the function of the organic particles even when environmental conditions such as heat are severe during production or use.

As a composition of this invention, compositions other than the said composite particle are not limited at all. For example, the composition of the present invention includes a composite particle composition substantially composed of the composite particles and a solvent for suspending the composite particles, a resin composition mainly comprising any resin material including the composite particles, It includes various embodiments such as a composition including composite particles and an arbitrary inorganic material, or a composite composition including the above composite particles, an arbitrary resin material, and an arbitrary inorganic material.
Speaking from the mode of use of the composition, specific examples of the composition include inks, adhesives, paints, and the like that appropriately include necessary components. For example, in embodiments as described above, the composition can be filmed on any substrate. According to the present invention, even when the filmed composition is exposed to a severe thermal environment or the like, the composite particles contained in the composition are less likely to impair the function of the organic particles contained in the composition as compared with the conventional one. In addition, it is possible to extend the service life of the organic particles.

Examples of the present invention will be described below. The organic particles A, the organic particles B, and the organic particles C used in each of the examples and the comparative examples are composed of 500 ml separable flasks containing the materials shown in Table 1 and 300 parts by mass of a 1.5% by mass aqueous polyvinyl alcohol solution. To 7000 rpm, 10 minutes, 25 ° C., immerse the suspension in a 90 ° C. water bath and heat polymerize with stirring at 250 rpm for 4 hours to produce particles, which are filtered and washed with water It was prepared by doing.

Example 1
0.1 g of organic particles A was added to 50 ml of ethanol to prepare an organic particle mixed solution. Add 0.6 ml of 28% ammonia water to the above organic particle mixture and use a magnetic stirrer (manufactured by Ishii Science Equipment Co., Ltd., Super Stirrer MS-2) to set the degree of stirring to medium for 25 minutes for 25 minutes. Stirred at 0 ° C. to obtain a stirrer. To the agitated material, 0.3 ml of tetraethoxysilane (TEOS) was added as a metal alkoxide. And it stirred using the same magnetic stirrer as the above on the conditions of 25 degreeC for 24 hours. As a result, hydrolytic condensation polymerization of tetraethoxysilane is performed to produce fine particles which are hydrolyzed polycondensation products of tetraalkoxysilane (inorganic particle production step; Stover method), and the fine particles are deposited on the surface of organic particles A. Thus, composite particles were prepared (coating process). Then, after centrifuging at 15000 rpm for 10 minutes, the stirred product was filtered through a 5 μm membrane to take out composite particles, washed with neoethanol (manufactured by Daishin Chemical Co., Ltd.), and vacuum dried at 60 ° C. The composite particle thus obtained was designated as Example 1.

(Example 2)
A composite particle was produced under the same conditions as in Example 1 except that the inorganic particle production process, the coating process, and the filtration process were set as one set, and this was repeated 5 times.

(Example 3)
A composite particle was produced under the same conditions as in Example 1 except that the addition amount of 28% ammonia water and tetraethoxysilane was increased five times that in Example 1, and this was designated as Example 3.

Example 4
A composite particle was produced under the same conditions as in Example 1 except that the organic particle used was changed to the organic particle B, and this was designated as Example 4.

(Example 5)
A composite particle was produced under the same conditions as in Example 4 except that the addition amounts of 28% ammonia water and tetraethoxysilane were increased five times as much as in Example 4. This was designated as Example 5.

(Example 6)
A composite particle was produced under the same conditions as in Example 1 except that the organic particle used was changed to the organic particle C, and this was designated as Example 6.

(Example 7)
Composite particles were produced under the same conditions as in Example 6 except that the addition amounts of 28% ammonia water and tetraethoxysilane were increased five times as much as in Example 6. This was designated as Example 7.

(Comparative Examples 1 to 3)
Organic particles A, organic particles B, and organic particles C were used as Comparative Example 1, Comparative Example 2, and Comparative Example 3, respectively.

Each Example and each Comparative Example obtained as described above were observed with an electron microscope and evaluated as follows. The evaluation results are shown in Table 2. Note that the arrows shown in Table 2 indicate that the values are the same as those on the left.

[Electron microscope observation]
An electron micrograph of each example and each comparative example was taken using a scanning electron microscope, and the appearance and the cut surface were observed as necessary. The coating layer formation evaluation was performed by such observation. The average particle size of the organic particles and the average particle size of the particulates present on the surface of the composite particles were measured as follows.

(Coating layer formation evaluation)
The appearance of the particles of each Example and each Comparative Example was observed with a scanning electron microscope (magnification 50,000 times). In addition, regarding the appearance of the particles in which the accumulation of particulate matter was not confirmed on the peripheral surface, the particles were cut, and the cut surface was observed with a scanning electron microscope (magnification 20,000 times). And the presence or absence of the coating layer formation in an Example and a comparative example was performed as follows. Specifically, when it corresponds to the following (A) or (B) below, it is judged that the coating layer exists on the surface, and when it corresponds to the following (C), it was judged that the coating layer does not exist. .
(A) A coating layer in which a large number of fine particles were deposited on the surface of the particle was observed .... (B) A layer distinct from the central particle was observed on the outer edge of the cut surface of the particle.・ ・ ・ ・ ・ Yes (C) No layer distinct from the central particle was observed on the outer edge of the cut surface of the particle.

(Measurement of average particle size of organic particles)
The organic particles A, the organic particles B, and the organic particles C were observed with an electron microscope using a scanning electron microscope (magnification of 50,000 times), the particle diameter was measured, and an average value was obtained. Table 2 shows the average particle diameters of the organic particles A, the organic particles B, and the organic particles C, and the lower limit value and the upper limit value of the actually measured values. In addition, regarding the measured value and average particle diameter of the particle size, Comparative Example 1 corresponds to organic particle A, Comparative Example 2 corresponds to organic particle B, and Comparative Example 3 corresponds to organic particle C.

(Measurement of average particle size of particulate matter on peripheral surfaces of Examples and Comparative Examples)
The peripheral surface was observed about the Example and the comparative example by the said electron microscope observation. As a result, in Example 2, Example 3, Example 5, and Example 7, many particulate matters were confirmed on the peripheral surface. On the other hand, in Example 1, Example 4, Example 6, and Comparative Example 1, Comparative Example 2, and Comparative Example 3, no particulate matter was confirmed on the peripheral surface, or a very small number of particulate matter was confirmed. .
Therefore, regarding Example 2, Example 3, Example 5, and Example 7 in which a large number of particulate matters were confirmed, the particle diameters of the particulate matters were measured and the average particle diameter was determined. The average particle diameter was obtained by measuring the particle diameters of 100 randomly selected particles in an electron micrograph and calculating the arithmetic average. In addition, regarding Example 4 in which a very small number of particulate matter was confirmed on the peripheral surface, the particle size of the particulate matter was measured.
The average particle diameter of the particulate matter of each Example obtained by the above measurement and the lower limit value and the upper limit value of the actually measured values are shown in Table 2 (for Example 4, only the lower limit value and the upper limit value).

(Overall observation)
In the electron microscope observation (magnification of 50,000 times), the particulate matter constituting the coating layer on the peripheral surfaces of Example 1, Example 6, Comparative Example 1, Comparative Example 2, and Comparative Example 3 was not confirmed. In Example 4, although minute particulate matter (measured value of 10 nm or more and 30 nm or less) was observed sparsely on the peripheral surface, it was not enough to cover the peripheral surface. As an example of the example in which no particulate matter was observed on the peripheral surface, a microscopic observation photograph of the appearance of Example 1 is shown in FIG.
Next, the composite particles of Example 1, Example 4, Example 6, Comparative Example 1, Comparative Example 2, and Comparative Example 3 (that is, organic particles A, organic particles B, and organic particles C) were cut, and the cut surface Were observed with a scanning electron microscope (magnification: 20,000 times). As an example of the cut surface photograph, the cut surface photograph of Example 1 is shown as FIG. 4A, and the photograph of Comparative Example 1 (organic particles A) is shown as FIG. 4B.
As a result of the observation, a whitish layer that substantially circulates around the outer edge of the cut surface of the center particle (that is, organic particle) was observed in the cut surfaces of Example 1, Example 4, and Example 6. On the other hand, in the observation of the cut surfaces of Comparative Example 1, Comparative Example 2, and Comparative Example 3 with an electron microscope, no whitish layer as described above was observed on the outer edge of the cut surface. In Example 1, Example 4, and Example 6, the coating layer was formed on the peripheral surface of the organic particles used, and the percentage of the residual material described later was higher than that of the target comparative example. Since the ratio increased, it was confirmed that the coating layer which consists of an inorganic substance was formed in the surrounding surface of an organic particle. In addition, since these examples were formed by the Stover method, it was inferred that such a coating layer was a film-like layer in which inorganic fine particles having a very small particle size were deposited on the surface of organic particles. .

In the electron microscope observation (magnification of 50,000 times), in Example 2, Example 3, Example 5, and Example 7, the particulate matter is densely concentrated on the entire surface of the composite particle, whereby a coating layer is formed. It was observed that In Example 2, Example 3, Example 5, and Example 7, a plurality of polycondensates of hydrolyzed particulate metal alkoxide are formed by the Stover method, and these are deposited on the peripheral surface of the organic particles. It was inferred that it was provided with a coated layer. A photograph of Example 5 is shown in FIG. 5 as an example of appearance observation of an example in which a large number of particulates are deposited on the peripheral surface.

(Percentage of residue%)
Each example and each comparative example were subjected to a combustion test (thermogravimetric / differential heat measurement test). In the above test, a thermogravimetric / differential thermal analyzer (model name: TG8120, manufactured by Rigaku Corporation) was used and heated from room temperature to 600 ° C. at a heating rate of 10 ° C./min in an air atmosphere, and then at 600 ° C. After heating for 30 minutes, the mass W2 (g) of the residue was measured. And the ratio (percentage%) of the mass W2 (g) of the residue with respect to the sample mass W1 (g) before combustion was calculated.

(Heat-resistant peak temperature)
The peak temperature of the exothermic peak indicating the end of combustion shown in the DTA curve obtained in the combustion test described above was defined as the heat resistant peak temperature. The higher the heat-resistant peak temperature indicating the end of combustion, the higher the heat resistance. In the DTA curve in this example, a slightly smaller exothermic peak appeared in the temperature range from the latter half of 400 ° C. to less than 600 ° C. after the appearance of the maximum exothermic peak. In the present invention, the heat-resistant peak temperature was measured by setting a slightly small exothermic peak appearing after the maximum exothermic peak as a peak representing the end of combustion.

As shown in Table 2, it was confirmed that the coating layer was formed in the surface of the organic particle from the result of the percentage of a residue in all the Examples.
More specifically, after completion of the combustion test, Example 1, Example 2, and Example 3 in which a coating layer was formed on organic particles A were significantly different from Comparative Example 1 using only organic particles A. The residual amount was confirmed and it was confirmed that the coating layer comprised with the inorganic substance was formed.
Similarly, compared to Comparative Example 2 using only organic particles B, Examples 4 and 5 in which a coating layer was formed on organic particles B, and Comparative Example 3 using only organic particles C were organic. In Examples 6 and 7 in which the coating layer was formed on the particles C, a significant residual amount was confirmed after the combustion test.
In Example 1, the coating process was performed once, and the combustion substance residual ratio was 1%, whereas in Example 2 in which the coating process was performed five times, the amount of residuals was more than five times that of Example 1. The ratio is shown. From this, it was confirmed that the formation efficiency of the coating layer was improved by using the composite particles in which the coating layer made of inorganic particles was formed and further repeating the coating process.
Although Comparative Examples 2 and 3 do not have a coating layer, the silica component (SiO ₂ in the silane coupling agent contained in the organic particle B or the organic particle C in the measurement of the percentage (%) of the residue. ) Remained unburned, so it was assumed that a significant value was shown.

Example 6 showed a similar heat-resistant peak temperature to Example 7 although the amount of the basic catalyst used was small. This is because Example 6 and Example 7 use organic particles C containing a large amount of a silane coupling agent, so that the binding efficiency between the organic particles C and the inorganic material is good, and the basic catalyst is relative. Even in Example 6 with a small amount, it was presumed that the coating layer was sufficiently formed.

From the results of the heat-resistant peak temperature of each example and the percentage of the residue, the larger the percentage value of the residue, the higher the heat-resistant peak temperature tends to be, and the heat resistance is improved by providing the composite particle with a coating layer. Confirmed to do.

In contrast to Example 1, Example 2, and Example 3, Example 4, Example 5, Example 6, and Example 7 using organic particles B and C containing a silane coupling agent are heat resistant peak temperatures. (Specifically, Example 4 and Example 6 are referred to for Example 1, and Example 5 and Example 7 are referred to for Example 2). Thereby, the effectiveness of including the silane coupling agent in the organic particles was confirmed.

From the above results, it was confirmed that the coating layer is formed by depositing fine inorganic particles on the surface of the organic particles regardless of physical stress by the composite particle manufacturing method of the present invention. In addition, it was confirmed that the composite particles having a coating layer composed of a plurality of inorganic particles on the surface of the organic particles have improved heat resistance.

The above embodiment includes the following technical idea.
(1) having organic particles and a coating layer covering the surface of the organic particles;
The composite particle, wherein the coating layer includes a polymer of a metal alkoxide.
(2) The composite particle according to (1), wherein the metal alkoxide polymer is a condensation polymer of metal alkoxide or a hydrolyzate of metal alkoxide.
(3) The composite particle according to (1) or (2), wherein the metal alkoxide is alkoxysilane.
(4) The composite particle according to (3), wherein the alkoxysilane is tetraethoxysilane or tetramethoxysilane.
(5) The composite particle according to any one of (1) to (4), wherein the organic particle includes a (meth) acrylic resin.
(6) The composite particle according to any one of (1) to (5), wherein the organic particle includes a compound having a polar group.
(7) The composite particle according to (6), wherein the compound includes a silane coupling agent.
(8) The composite particle according to any one of (1) to (7), wherein the organic particle contains a functional material.
(9) The functional material is a semiconductor particle,
The composite particles according to claim 8, wherein the organic particles include one or more of the semiconductor particles.
(10) The composite particle according to any one of (1) to (9), wherein the coating layer includes a plurality of inorganic particles composed of a polymer of the metal alkoxide.
(11) The composite particles according to (10), wherein the average particle diameter of the organic particles is 0.01 μm or more and 30 μm or less, and the average particle diameter of the inorganic particles is 3 nm or more and 150 nm or less.
(12) The average particle diameter of the organic particles is 0.01 μm or more and 30 μm or less, and the average film thickness of the coating layer is 5 nm or more and 400 nm or less, according to any one of (1) to (11) above. Composite particles.
(13) The composite particle according to any one of (1) to (12), wherein the coating layer is configured in multiple layers.
(14) A composition comprising the composite particles according to any one of (1) to (13) above.
(15) an inorganic particle production step of polymerizing metal alkoxide to produce inorganic particles;
A coating step of depositing the inorganic particles around the organic particles to form a coating layer;
A method for producing composite particles, comprising:
(16) The method for producing composite particles according to (15), wherein the inorganic particle production step includes implementation of a sol-gel method.
(17) The metal alkoxide is an alkoxysilane,
The method for producing composite particles according to the above (15) or (16), wherein the inorganic particle production step includes a Stover method.
(18) The method for producing composite particles according to any one of (15) to (17), including an organic particle production step of producing the organic particles by suspension polymerization.
(19) The method for producing composite particles according to any one of (15) to (18), wherein the inorganic particle preparation step and the coating step are continuously performed in the same liquid phase.
(20) The coating step includes a first coating step and a second coating step,
The first coating step is a step of adding composite liquid containing the inorganic particles and the organic particles to a reaction vessel and stirring to produce composite particles including a single-layer coating layer.
In the second coating step, after completion of the first coating step, the composite particles including the single-layer coating layer are taken out from the reaction tank, and the single-layer composite particles and the inorganic particles or the inorganic particles are prepared in the reaction tank. The method for producing composite particles according to any one of (15) to (19), wherein the mixed solution containing a raw material is added and stirred to produce composite particles having a multilayer coating layer.

DESCRIPTION OF SYMBOLS 10 ... Organic particle 20 ... Coating layer 30 ... Inorganic particle 100 ... Composite particle

Claims (18)

Organic particles and a coating layer covering the surface of the organic particles,
The composite particle, wherein the coating layer includes a polymer of a metal alkoxide. The composite particle according to claim 1, wherein the polymer of the metal alkoxide is a condensation polymer of metal alkoxide or a hydrolyzate of metal alkoxide. The composite particle according to claim 1, wherein the metal alkoxide is alkoxysilane. The composite particle according to claim 3, wherein the alkoxysilane is tetraethoxysilane or tetramethoxysilane. The composite particle according to any one of claims 1 to 4, wherein the organic particle contains a (meth) acrylic resin. The composite particle according to claim 1, wherein the organic particle includes a compound having a polar group. The composite particle according to claim 6, wherein the compound contains a silane coupling agent. The composite particles according to claim 1, wherein the organic particles contain a functional material. The functional material is a semiconductor particle;
The composite particles according to claim 8, wherein the organic particles include one or more of the semiconductor particles. The composite particle according to any one of claims 1 to 9, wherein the coating layer includes a plurality of inorganic particles composed of a polymer of the metal alkoxide. 11. The composite particle according to claim 10, wherein the average particle diameter of the organic particles is 0.01 μm or more and 30 μm or less, and the average particle diameter of the inorganic particles is 3 nm or more and 150 nm or less. 12. The composite particle according to claim 1, wherein an average particle diameter of the organic particles is 0.01 μm or more and 30 μm or less, and an average film thickness of the coating layer is 5 nm or more and 400 nm or less. A composition comprising the composite particles according to any one of claims 1 to 12. An inorganic particle production step of polymerizing metal alkoxide to produce inorganic particles;
A coating step of depositing the inorganic particles around the organic particles to form a coating layer;
A method for producing composite particles, comprising: The composite particle manufacturing method according to claim 14, wherein the inorganic particle manufacturing step includes implementation of a sol-gel method. The metal alkoxide is alkoxysilane;
The composite particle manufacturing method according to claim 14 or 15, wherein the inorganic particle manufacturing step includes a Stover method. The method for producing composite particles according to any one of claims 14 to 16, further comprising an organic particle production step of producing the organic particles by suspension polymerization. The composite particle manufacturing method according to any one of claims 14 to 17, wherein the inorganic particle preparation step and the coating step are continuously performed in the same liquid phase.

Images