JP7385734B2 - Hollow particles, resin compositions, and resin molded bodies and laminates using the resin compositions - Google Patents

Description

The present invention relates to hollow particles, a resin composition, and a resin molded article and a laminate using the resin composition.

For example, in recent years, in the field of information and communication equipment, there has been a demand for electronic components (typically resin components) to have lower dielectric constants and lower dielectric loss tangents in order to support communications in high frequency bands. In order to achieve this, it has been proposed, for example, to include air with a low dielectric constant in the member. Specifically, it has been proposed to introduce air using hollow particles (for example, see Patent Document 1). In this way, containing air can also contribute to reducing the weight of the member.

On the other hand, it is also required to ensure the durability of the member (for example, mechanical strength such as flexural modulus, and dimensional stability).

Japanese Patent Application Publication No. 2007-56158

The present invention has been made to solve the above problems, and one of the objects is to achieve a lower dielectric constant and a lighter weight while ensuring durability.

According to one aspect of the invention, hollow particles are provided. The hollow particles contain silica, have an aspect ratio of 2 or more, and are plate-shaped.
In one embodiment, the length of the hollow particle is 0.1 μm or more and 10 μm or less.
In one embodiment, the thickness of the hollow particles is 0.01 μm or more and 5 μm or less.
In one embodiment, the shell thickness of the hollow particles is 10 nm or more and 100 nm or less.
In one embodiment, the hollow particles have a hollowness ratio of 20% or more and 95% or less.

According to another aspect of the invention, a resin composition is provided. This resin composition includes a resin and the hollow particles described above.

According to yet another aspect of the present invention, a resin molded article is provided. This resin molded body is formed from the above resin composition.

According to yet another aspect of the invention, a laminate is provided. This laminate has a resin layer formed from the above resin composition.
In one embodiment, the thickness of the resin layer is 25 μm or less.

According to the present invention, by using plate-shaped hollow particles, it is possible to achieve a lower dielectric constant and a lighter weight while ensuring durability.

It is a schematic diagram explaining a major axis and thickness. It is a schematic sectional view of the layered product in one embodiment of the present invention. It is a TEM observation photograph (10000 times) of the hollow particle of Example 1. 1 is a TEM observation photograph (100,000 times magnification) of the hollow particles of Example 1. This is a SEM observation photograph (20,000 times) of the core particles used in Example 1.

Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

(Definition of terms)
Definitions of terms used herein are as follows.
1. Long diameter of particles This is a value measured by scanning electron microscopy (SEM) or transmission electron microscopy (TEM) observation, and is the average value of the long diameters (for example, L in FIG. 1) of randomly selected primary particles. Note that primary particles are the smallest particles observed by SEM or TEM, and are distinguished from aggregated particles (secondary particles).
2. Particle Thickness This is a value measured by SEM or TEM observation, and is the average value of the thicknesses of randomly selected primary particles (for example, T in FIG. 1).
3. Aspect ratio (length/thickness)
This is a value calculated by dividing the thickness of the particle from the major axis of the particle.
4. Particle size Particle size is the average particle size in particle size distribution measurement.

A. Hollow Particles Hollow particles in one embodiment of the invention are typically formed of silica. The content of silica in the hollow particles is, for example, 95% by weight or more, preferably 97% by weight or more, and more preferably 98% by weight or more.

The hollow particles have a plate-like shape. By adopting a plate shape, the above-mentioned durability, low dielectric constant, and weight reduction can be achieved at the same time. Further, it is possible to sufficiently cope with downsizing (thinning) of the members used. Furthermore, it is easy to achieve both a high hollowness ratio and the strength of the hollow particles.

The aspect ratio of the hollow particles is 2 or more, preferably 3 or more, and more preferably 4 or more. On the other hand, the aspect ratio of the hollow particles is, for example, 100 or less, preferably 60 or less, and more preferably 50 or less. According to such an aspect ratio, for example, processability when producing a resin composition described below can be excellent.

The long axis of the hollow particles is preferably 0.1 μm or more, more preferably 0.2 μm or more. With such a long axis, the hollowness ratio described below can be fully satisfied. On the other hand, the length of the hollow particles is preferably 10 μm or less, more preferably 5 μm or less. Such a long axis can greatly contribute to the above-mentioned size reduction (thin film reduction).

The thickness of the hollow particles is preferably 0.01 μm or more, more preferably 0.05 μm or more, particularly preferably 0.1 μm or more. With such a thickness, the hollowness ratio described below can be fully satisfied. On the other hand, the thickness of the hollow particles is preferably 5 μm or less, more preferably 3 μm or less, particularly preferably 2 μm or less. Such a thickness can greatly contribute to the above-mentioned size reduction (thin film reduction).

The shell thickness of the hollow particles is preferably 10 nm or more, more preferably 15 nm or more. Such a thickness can effectively prevent the hollow particles from being broken, for example, when producing the resin composition described below. On the other hand, the thickness of the shell of the hollow particles is preferably 100 nm or less, more preferably 60 nm or less. Such a thickness can sufficiently satisfy the hollowness ratio described below, and can greatly contribute to lower dielectric constant and weight reduction. Note that the thickness of the shell can be measured by TEM observation. For example, it can be determined by measuring the shell thickness of randomly selected hollow particles and calculating the average value.

The hollowness ratio of the hollow particles is preferably 20% or more, more preferably 30% or more, still more preferably 40% or more, particularly preferably 50% or more. Such a hollowness ratio can greatly contribute to lower dielectric constant and weight reduction, for example. On the other hand, the hollowness ratio of the hollow particles is preferably 95% or less, more preferably 90% or less. According to such a hollowness ratio, it is possible to effectively prevent the hollow particles from being broken, for example, when producing the resin composition described below. Note that the hollowness ratio can be calculated from the volume of the core particle and the volume of the hollow particle, which will be described later.

The pore volume of the hollow particles is preferably 1.5 cm ³ /g or less, more preferably 1.0 cm ³ /g or less.

The particle size of the hollow particles is preferably 0.1 μm or more, more preferably 0.5 μm or more. On the other hand, the particle size of the hollow particles is preferably 10 μm or less, more preferably 5 μm or less.

The BET specific surface area of the hollow particles may be, for example, 10 m ² /g or more, or 30 m ² /g or more. On the other hand, the BET specific surface area of the hollow particles is preferably 250 m ² /g or less, more preferably 200 m ² /g or less.

In one embodiment, the hollow particles are surface-treated with any suitable surface treatment agent. Examples of surface treatment agents include higher fatty acids, anionic surfactants, cationic surfactants, phosphate esters, coupling agents, esters of polyhydric alcohols and fatty acids, acrylic polymers, and silicone treatment agents. At least one selected from the group consisting of is used.

Any suitable method may be employed as the method for manufacturing the hollow particles. In one embodiment, a method for producing hollow particles includes coating a core particle with a shell-forming material to obtain a core-shell particle, and removing the core particle from the core-shell particle.

As the core particles, any suitable particles may be employed as long as the hollow particles can be produced. Specifically, the shape of the core particle is preferably plate-like. The aspect ratio of the core particles is preferably 2 or more, more preferably 3 or more. On the other hand, the aspect ratio of the core particles is preferably 100 or less, more preferably 70 or less.

The major diameter of the core particle is preferably 0.1 μm or more, more preferably 0.2 μm or more. On the other hand, the major diameter of the core particles is preferably 10 μm or less, more preferably 5 μm or less. The thickness of the core particle is preferably 0.01 μm or more, more preferably 0.1 μm or more. On the other hand, the thickness of the core particle is preferably 5 μm or less, more preferably 2 μm or less.

As the material for forming the core particles, for example, a material that can be dissolved in an acidic solution, which will be described later, is used. In this case, the material for forming the core particles includes, for example, hydroxides such as magnesium hydroxide, hydrotalcite, magnesium oxide, and calcium hydroxide; oxides of hydrotalcite; oxides such as zinc oxide and calcium oxide; Examples include carbonate compounds such as calcium carbonate. Among these, magnesium hydroxide and hydrotalcite are preferably used, and magnesium hydroxide is particularly preferably used. For example, this is because it can exist stably in an aqueous system. In addition, gas (for example, carbon dioxide gas) is not generated when the particles are dissolved in an acidic solution, which will be described later, and defects can be suppressed from occurring in the hollow particles obtained.

As the shell forming material, for example, alkoxysilanes such as water glass (Na ₂ O.nSiO ₂ ) and tetraethoxysilane (Si(OCH ₂ CH ₃ ) ₄ ) are used.

The amount of coverage with shell-forming material may be adjusted by any suitable method. For example, the amount of coating can be adjusted by controlling the pH value when coating core particles with a shell-forming material containing water glass. Specifically, the water glass may be stable in a high pH region (eg, pH 11 or higher). Thus, for example, by lowering the pH value (eg, to pH 7 or lower) using a pH adjuster, water glass molecules can be condensed and silica can be efficiently precipitated onto the core particles. As the pH adjuster, preferably an acidic solution is used. Specifically, solutions of strong acids such as hydrochloric acid, nitric acid, and sulfuric acid, and solutions of weak acids such as ammonium nitrate and ammonium sulfate are preferably used. The amount of the pH adjuster added is preferably, for example, 85% to 98% in terms of neutralization rate with respect to water glass. If the neutralization rate is too high, there is a risk that not only silica will precipitate on the core particles, but also individual silica particles will be produced. Furthermore, there is a risk that the core particles will be dissolved during coating with the shell-forming material. Note that the formation of the shell (specifically, the precipitation and formation rate of the shell) can also be promoted by heating (eg, to 80° C. to 90° C.) when the core particles are coated with the shell-forming material.

The core particles are typically removed by dissolving them in an acidic solution. As the acidic solution, for example, hydrochloric acid, sulfuric acid, and nitric acid are used. The melting temperature is, for example, 30°C to 90°C, preferably 50°C to 70°C. According to such a temperature, the core particles can be efficiently dissolved while suppressing problems such as the shell becoming easily broken. In one embodiment, hydrochloric acid is used as the acidic solution, for example, from the viewpoint of reusing the substance (eg, salt) obtained by reacting with the core particles.

Preferably, the hollow particle manufacturing method further includes firing the shell (for example, under an atmospheric atmosphere). By performing the calcination, for example, the hydrophobicity of the shell can be improved (specifically, the silanol groups of the shell are changed to siloxane), and the dielectric properties of the obtained hollow particles can be improved. Firing can be performed at any suitable timing. Preferably, this is carried out after removing the core particles from the core-shell particles. The firing temperature is, for example, 300°C to 1300°C. The firing time is, for example, 1 hour to 20 hours.

In one embodiment of the present invention, the hollow particles are used as a functional agent for resin materials. The resin composition containing the hollow particles described above will be explained below.

B. Resin Composition A resin composition in one embodiment of the present invention includes a resin and the hollow particles described above.

Any appropriate resin may be selected as the resin, depending on, for example, the intended use of the resulting resin composition. For example, the resin may be a thermoplastic resin or a thermosetting resin. Specific examples of the resin include epoxy resin, polyimide resin, polyamide resin, polyamideimide resin, polyetheretherketone resin, polyester resin, polyhydroxypolyether resin, polyolefin resin, fluororesin, liquid crystal polymer, and modified polyimide. These may be used alone or in combination of two or more.

The content of the hollow particles in the resin composition is preferably 0.1% by weight or more, more preferably 0.5% by weight or more. On the other hand, the content ratio is preferably 90% by weight or less, more preferably 85% by weight or less.

In the resin composition, the hollow particles are preferably contained in an amount of 0.5 parts by weight or more, more preferably 1 part by weight or more, based on 100 parts by weight of the resin. On the other hand, the hollow particles are preferably contained in an amount of 300 parts by weight or less, more preferably 200 parts by weight or less, per 100 parts by weight of the resin.

The volume ratio of hollow particles in the resin composition is preferably 0.1% or more, more preferably 0.5% or more. On the other hand, the volume ratio of hollow particles in the resin composition is preferably 70% or less, more preferably 60% or less. For example, this is because the processability when producing a resin composition can be excellent.

The resin composition may contain optional components. Optional components include, for example, a curing agent (specifically, a curing agent for the above resin), a stress reducing agent, a coloring agent, an adhesion improver, a mold release agent, a fluidity regulator, a defoaming agent, a solvent, and a filler. can be mentioned. These may be used alone or in combination of two or more. In one embodiment, the resin composition includes a curing agent. The content of the curing agent is, for example, 1 part by weight to 150 parts by weight based on 100 parts by weight of the resin.

Any suitable method may be employed as a method for producing the resin composition. Specifically, the resin composition is obtained by dispersing the hollow particles in the resin using any appropriate dispersion method. Examples of the dispersion method include dispersion using various stirrers such as a homomixer, a disper, and a ball mill, dispersion using an autorotation-revolution mixer, dispersion using shear force using three rolls, and dispersion using ultrasonic treatment.

The resin composition is typically formed into a resin molded article into a desired shape. For example, it is a resin molded body formed into a desired shape using a mold. When molding a resin molded article, the resin composition may be subjected to any appropriate treatment (for example, curing treatment).

In one embodiment of the present invention, the resin composition is used as a resin layer included in a laminate. Hereinafter, a laminate having a resin layer formed from the above resin composition will be explained.

C. Laminate FIG. 2 is a schematic cross-sectional view of a laminate in one embodiment of the present invention. The laminate 10 has a resin layer 11 and a metal foil 12. The resin layer 11 is formed from the above resin composition. Specifically, the resin layer 11 includes the resin and the hollow particles. In the resin layer 11, it is preferable that the in-plane direction of the plate-shaped hollow particles is oriented in the in-plane direction of the resin layer 11. This is because it can contribute to making the resin layer thinner. Although not shown, the laminate 10 may include other layers. For example, a base material (typically a resin film) that is laminated on one side of the resin layer 11 (the side on which the metal foil 12 is not placed) may be used. The laminate 10 is typically used as a printed circuit board.

The thickness of the resin layer is, for example, 5 μm or more, preferably 10 μm or more. On the other hand, the thickness of the resin layer is, for example, 100 μm or less, preferably 50 μm or less, and more preferably 25 μm or less. With such a thickness, for example, it is possible to sufficiently cope with the miniaturization of electronic components in recent years.

Any suitable metal may be used as the metal forming the metal foil. Examples include copper, aluminum, nickel, chromium, and gold. These may be used alone or in combination of two or more. The thickness of the metal foil is, for example, 2 μm to 35 μm.

Any suitable method may be employed as a method for producing the laminate. For example, the resin composition is coated on the base material to form a coating layer, and the metal foil is laminated on the coating layer to obtain a laminate. As another specific example, a laminate is obtained by coating the metal foil with the resin composition to form a coating layer. Typically, the coating layer is cured by applying a treatment such as heating or light irradiation to the coating layer at any appropriate timing. During coating, the resin composition may be dissolved in any suitable solvent.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. The method for measuring each characteristic is as follows unless otherwise specified.
1. Long axis of particle The long axis was calculated by SEM observation or TEM observation. Specifically, the major diameters of 100 primary particles randomly selected from SEM photographs or TEM photographs of the particles were measured, and the arithmetic mean (average major diameter) of the obtained measured values was determined. Note that the magnification for SEM observation of the core particles was 20,000 times, and the magnification for TEM observation of the hollow particles was 10,000 times.
2. Thickness The thickness of the particles and the thickness of the shell of the particles were calculated by SEM observation or TEM observation. Specifically, the thickness of 100 primary particles randomly selected from SEM photographs or TEM photographs of the particles was measured, and the arithmetic mean (average thickness) of the obtained measured values was determined. Note that the magnification for SEM observation of the core particle was 50,000 times, and the magnification for TEM observation of the hollow particle was 10,000 times and 10,000 times.
3. Aspect Ratio Aspect ratio was calculated by SEM observation or TEM observation. Specifically, the aspect ratio was calculated by dividing the average major axis of the particles by the average thickness of the particles.
4. Hollowness ratio Calculated from the volume of the core particle and the volume of the hollow particle. Specifically, it was calculated from (volume per core particle)/(volume per hollow particle)×100. The volume per particle of the core particle and the hollow particle was calculated by approximating the actual shape by the volume of a cylinder, using the major axis as the diameter of the circle, and the thickness as the height of the cylinder.
5. Particle size Particle size (average secondary particle size) was measured by dynamic light scattering using "ELSZ-2" manufactured by Otsuka Electronics (analysis conditions were scattering intensity distribution). A sample for measurement was prepared by adding 0.05 g of particles to 70 mL of water and then subjecting the mixture to ultrasonication at 300 μA for 3 minutes.
6. Pore volume Measured using "BELsorp-max" manufactured by Microtrac Bell Co., Ltd. Specifically, it was measured by a constant volume gas adsorption method using nitrogen gas, and the pore volume was determined by analysis using the BJH method.
7. BET specific surface area Measured using "BELsorp-mini" manufactured by Microtrac Bell Co., Ltd. Specifically, it was measured by a constant volume gas adsorption method using nitrogen gas, and the specific surface area was determined by analysis using the BET multipoint method.

[Example 1]
Plate-shaped magnesium hydroxide particles having a major diameter of 0.8 μm, a thickness of 0.2 μm, and an aspect ratio of 4 were adjusted to a solid content concentration of 60 g/L using ion-exchanged water to obtain a slurry of magnesium hydroxide.

Next, 6.7 L of the obtained slurry of magnesium hydroxide was heated to 80° C. while stirring, and 0.57 mol/L of No. 3 water glass (Na ₂ O 3.14 SiO ₂ , Fuji Film Wa 268 ml of Hikari Pure Chemical Industries, Ltd.) was added over 10 minutes. Thereafter, 1340 ml of No. 3 water glass and 3.25 L of 0.5N hydrochloric acid were simultaneously added. Here, No. 3 water glass was added over 50 minutes, and hydrochloric acid was added over 60 minutes. The slurry thus obtained was aged for 30 minutes, then dehydrated and washed with water to obtain a cake of core-shell particle precursors.

Next, the obtained core-shell particle precursor cake was adjusted to a solid concentration of 60 g/L with ion-exchanged water, heated to 80°C while stirring, and added with 268 ml of No. 3 water glass containing 0.57 mol/L. was added over 10 minutes. Thereafter, 670 ml of No. 3 water glass and 1.9 L of 0.5N hydrochloric acid were simultaneously added. Here, No. 3 water glass was added over 25 minutes, and hydrochloric acid was added over 35 minutes. The slurry thus obtained was aged for 30 minutes, then dehydrated and washed with water to obtain a cake of core-shell particles.
Here, when the core-shell particles obtained using FT-IR ("FT/IR-4100" manufactured by JASCO) were measured by the ATR method, only a peak derived from OH of magnesium hydroxide near 3500 to 3800 cm ^-1 was found. Instead, a peak derived from Si--O--Si near 1,000 to 1,300 cm ^-1 was confirmed.

Next, 21.6 L of 0.7N hydrochloric acid was added to the obtained core-shell particles, and the particles were resuspended under stirring at room temperature. After adjusting the solid content concentration of the core-shell particles to 25 g/L, the particles were heated to 60°C. The core particles were dissolved by heating and aging for 1 hour to obtain a slurry of hollow silica.
The obtained hollow silica slurry was dehydrated and washed with water to form a hollow silica cake, and this hollow silica cake was dried at 60°C for 28 hours to form hollow silica particles (length: 0.86 μm, thickness: 0.26 μm, aspect ratio: ratio: 3.3, shell thickness: 30 nm, hollow ratio: 66%, particle size: 0.95 μm, pore volume: 0.67 cm ³ /g, BET specific surface area: 123 m ² /g).

When hollow silica particles obtained using FT-IR (JASCO's "FT/IR-4100") were measured by the ATR method, an OH-derived peak near 3500 to 3800 cm ^-1 of magnesium hydroxide particles was confirmed. However, only a peak derived from Si--O--Si near 1000 to 1300 cm ^-1 was confirmed. Further, when the hollow silica particles were analyzed by X-ray diffraction ("EMPYRIAN" manufactured by PANalytical), no magnesium hydroxide peak was observed, indicating that the particles were amorphous silica. Note that, based on the weight of the hollow silica particles obtained, the proportion of silica in the core-shell particles was 26% by weight.

[Example 2]
When forming core-shell particles, hollow particles (length: 0.88 μm, thickness: 0.28 μm, aspect ratio: 3. 1. Shell thickness: 40 nm, hollow ratio: 59%, particle size: 1.20 μm, pore volume: 0.50 cm ³ /g, BET specific surface area: 81 m ² /g).

[Example 3]
Instead of plate-shaped magnesium hydroxide particles with a major diameter of 0.8 μm, a thickness of 0.2 μm, and an aspect ratio of 4, plate-shaped hydrotalcite particles with a major diameter of 0.2 μm, a thickness of 0.07 μm, and an aspect ratio of 2.9 (Kyowa Chemical Industry Co., Ltd.) were used. Hollow particles (long diameter: 0.246 μm, thickness: 0.116 μm, aspect ratio: 2.1, shell thickness: 23 nm, hollow ratio: 53%, particle size: 0.94 μm, pore volume: 0.85 cm ³ /g, BET specific surface area :135 m ² /g) was obtained.

<TEM observation>
The results of observation of the hollow particles of Example 1 using a transmission electron microscope (JEM-2100PLUS manufactured by JEOL Ltd.) are shown in FIG. From FIG. 3, it was confirmed that the particles were plate-shaped hollow particles with a shell (silica layer) thickness of 30 nm. Incidentally, FIG. 4 shows a SEM photograph of the magnesium hydroxide particles used as the core particles, and it was confirmed from FIGS. 3 and 4 that the particles were hollow particles that maintained the plate-like shape of the core particles.

<Resin composition>
(1) Mixing by ultrasonication 1 g of bisphenol F type epoxy resin (“JER806” manufactured by Mitsubishi Chemical Corporation), 0.38 g of curing agent (“LV11” manufactured by Mitsubishi Chemical Corporation) and obtained in Example 1. A resin composition 1 was obtained by mixing 0.04 g of hollow silica particles. The mixing was performed by applying ultrasonic treatment for 1 minute using "NS-200-60" manufactured by Nippon Seiki Seisakusho Co., Ltd.
(2) Mixing using a homogenizer 5 g of bisphenol F type epoxy resin (“JER806” manufactured by Mitsubishi Chemical Corporation), 1.9 g of curing agent (“LV11” manufactured by Mitsubishi Chemical Corporation) and hollow particles obtained in Example 1 Resin composition 2 was obtained by mixing 0.2 g of silica particles. Mixing was performed using a handy homogenizer ("T10 Basic" manufactured by IKA Japan Co., Ltd.) at 8000 rpm for 5 minutes.
(3) Mixing using a rotation-revolution mixer 5 g of bisphenol F-type epoxy resin (“JER806” manufactured by Mitsubishi Chemical Corporation), 2.5 g of curing agent (“LV11” manufactured by Mitsubishi Chemical Corporation) and obtained in Example 1. 0.875 g of hollow silica particles were mixed to obtain a resin composition 3. The mixing was performed using a rotation and revolution mixer ("Kakuhunter SK-300SVII" manufactured by Photo Chemical Co., Ltd.) at 1700 rpm for 3 minutes.

<Resin molded body>
Each of the resin compositions 1-3 was poured into a silicone resin mold with a thickness of 2 mm, and cured at 80° C. for 3 hours to obtain a resin molded article 1-3.

The obtained molded body was cut with a cross-section polisher (“IB-09010CP” manufactured by JEOL), and the cross section was observed with an SEM (“JSM-7600F” manufactured by JEOL). However, no destruction of hollow particles was confirmed. Furthermore, in any of the resin molded bodies 1-3, no resin was found to have penetrated into the interior of the hollow particles.

The hollow particles of the present invention can typically be suitably used for electronic materials. In addition, it can be used in, for example, heat insulating materials, soundproofing materials, impact buffering materials, stress buffering materials, optical materials, and lightweight materials.

L Long axis T Thickness 10 Laminated body 11 Resin layer 12 Metal foil

Claims (9)

A resin containing plate-shaped hollow particles containing silica , having an aspect ratio of 2 or more and 100 or less, a shell thickness of 10 nm or more and 100 nm or less, and a pore volume of 1.5 cm ³ /g or less , and a resin. Composition . The resin composition according to claim 1, wherein the hollow particles have a major axis of 0.1 μm or more and 10 μm or less. The resin composition according to claim 1 or 2 , wherein the hollow particles have a thickness of 0.01 μm or more and 5 μm or less. The resin composition according to any one of claims 1 to 3 , wherein the hollow particles have a hollowness ratio of 20% to 95% . A resin molded article formed from the resin composition according to any one of claims 1 to 4 . A method for producing the resin composition according to claim 1, comprising:
obtaining the hollow particles by coating the core particles with a shell-forming material, and removing the core particles from the core shell particles;
A method for producing a resin composition, comprising: The method for producing a resin composition according to claim 6, wherein the core particles are magnesium hydroxide or hydrotalcite. The method for producing a resin composition according to claim 6 or 7, wherein the shell forming material is water glass. The method for producing a resin composition according to any one of claims 6 to 8, wherein the hollow particles are fired after removing the core particles.

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