JP5537258B2 - Method for producing bell structure particles - Google Patents

Description

The present invention relates to a bell structure particle that has few manufacturing limitations, is excellent in heat resistance, and has a high ability to attenuate vibration and sound.

In recent years, bell structures have attracted attention as materials for damping materials such as damping materials and sound insulation plates used for the purpose of absorbing vibration or absorbing sound. The bell structure means a structure in which core fine particles smaller than the shell are encapsulated in the holes of the shell. When such a bell structure is irradiated with vibration or sound, the incident kinetic energy is converted into the motion of the nuclear particles in the vacancies of the shell and consumed. Can be attenuated. For example, Patent Document 1 describes a vibration damping material including such a bell structure.

In Patent Document 1, the core particles are arranged in the pores of the porous plate-like body. For example, if particles having a bell structure (bell structure particles) are used, the bell structure particles are dispersed in an appropriate binder. By applying them, it is possible to easily manufacture a member to which vibration damping properties and sound insulation properties are imparted.

Patent Literature 2 and Patent Literature 3 disclose bell structure particles having a shell having a hollow portion and a nucleus that absorbs kinetic energy incident on the hollow portion from the outside.
In Patent Document 2, an intermediate material having sublimation characteristics or evaporation characteristics is provided between the shell of the organic material and the core of the inorganic material, and the intermediate material is heated to a predetermined temperature to be sublimated or evaporated outside the shell. A method for producing the bell structure particles is described. In Patent Document 3, an intermediate material made of a polar solvent is provided between the shell of the organic material and the core of the inorganic material, and the intermediate material is heated to a predetermined temperature to evaporate the shell material. A method for producing bell structure particles is described which forms a space between the shell and the nucleus inside.

However, since the bell structure particles described in Patent Documents 1 and 2 use a sublimable material or an organic solvent as a space forming material, the space forming material layer becomes unstable at the time of shell formation, and a uniform bell structure particle is manufactured. There was a problem that it was difficult to do. In addition, the bell structure particles described in Patent Documents 1 and 2 are either shells or core fine particles, or both are made of a resin material. While the bell structure particles using such a resin material are easy to manufacture, there is a problem that the heat resistance is low. Further, when the shell body is made of a resin material, there is a problem that the shell body is melted or broken due to heating or impact during kneading with the matrix constituting the damping material. Furthermore, in the case of bell structure particles using a resin material, there is a problem that the consumption efficiency of incident kinetic energy is low, and vibrations and sounds may not be attenuated as expected.

On the other hand, in Patent Document 4, the difference between the shrinkage rates is used when the core-shell particles of the ceramic material that is the core material and the ceramic material that is the shell material are prepared and then sintered. Thus, a method for forming a void between the nucleus and the shell is described. However, in the method described in Patent Document 4, the core and the shell may be fused during sintering, and the material is extremely limited. There was a problem.

In Patent Document 5, a carbonate intermediate layer is formed on the surface of a core made of an inorganic material, a metal oxide shell is formed on the surface of the intermediate layer, and then the carbonate is removed with an acid. Is disclosed. However, in the method described in Patent Document 5, when the carbonate is removed with an acid, the shell of the metal oxide is deteriorated, or pores from which the carbonate is eluted are formed in the shell. As a result, the bell structure particles having sufficient strength cannot be produced.

Japanese Patent Laid-Open No. 9-226035 JP 2000-148156 A JP 2006-249150 A JP 2006-335611 A JP 2008-74645 A

It is an object of the present invention to provide bell structure particles that have few manufacturing restrictions, are excellent in heat resistance, and have a high ability to attenuate vibration and sound.

The present invention is a bell structure particle in which core fine particles smaller than the shell body are encapsulated in pores of the shell body, and both the shell body and the core fine particle are bell structure particles made of an inorganic material.
The present invention is described in detail below.

As a result of intensive studies, the present inventor has produced bell structure particles in which both the shell and the core particles are made of an inorganic material simply and easily by using a resin for the intermediate layer between the core and the core particles. I found out that I can do it. Then, the bell structure particles produced by this production method, both of the shell and the core fine particles made of an inorganic material, are found to be extremely excellent in heat resistance and have a high ability to attenuate vibrations and sounds. Was completed.

The bell structure particle of the present invention has a structure in which core fine particles smaller than the shell are encapsulated in the pores of the shell. The schematic diagram showing an example of the bell structure particle | grains of this invention was shown in FIG.1 and FIG.2.

The above shell means particles having pores. In FIG. 1 and FIG. 2, it is described as a single-pore particle having only one hole, but it is not limited to this. That is, a porous particle having a plurality of pores may be used as long as it has pores that can contain the above-mentioned core fine particles.
The shape (external appearance) of the shell is not particularly limited, but a spherical shape is preferable.
The shape of the holes in the shell is not particularly limited, but a spherical shape is preferable.

The number of core fine particles contained in the pores of the shell may be one, or two or more. FIG. 1 shows a bell structure particle containing only one core particle, and FIG. 2 shows a bell structure particle containing two or more core particles.
The shape of the core fine particle is not particularly limited, but a spherical shape is preferable.

Both the shell and the core fine particles are made of an inorganic material. High heat resistance can be exhibited when the shell and the core fine particles are made of an inorganic material. In addition, since the nuclear fine particles are inorganic materials, the specific gravity is heavier than that of resin materials, so that the kinetic energy consumption efficiency is higher than that of conventional resin-made bell structure particles, and vibration and sound are attenuated. Performance can be improved.

The inorganic material constituting the shell and the core fine particles is not particularly limited, and examples thereof include metals of 4 to 14 groups, alloys containing these as main components, and oxides, nitrides, and carbides thereof.
Examples of the metal include aluminum, silicon, titanium, vanadium, iron, cobalt, copper, nickel, zinc, germanium, zirconium, molybdenum, rhodium, palladium, indium, tin, platinum, and gold.
Examples of the alloy include stainless steel and solder.
The oxides, nitrides, and carbides of the above metals and alloys containing them as main components include, for example, aluminum oxide, silicon oxide, titanium oxide, iron oxide, zinc oxide, indium oxide, tin oxide, oxide (indium-tin), Examples thereof include oxidation (zinc-aluminum), oxidation (zinc-gallium), silicon nitride, and silicon carbide.
These inorganic materials may be used independently and 2 or more types may be used together. Of these, silicon oxide (silica), titanium oxide (titania), iron oxide (ferrite), silicon carbide, and nickel are suitable as the inorganic material constituting the core fine particles because they can be manufactured at low cost.
In addition, the inorganic material which comprises the said shell, and the inorganic material which comprises the said nuclear fine particle may be the same, and may differ.

In the bell structure particles of the present invention, only the core fine particles may be included in the pores of the shell, or a liquid may be included in addition to the core fine particles. By including the liquid, the performance of attenuating vibration and sound can be further improved.

The particle diameter of the bell structure particles of the present invention varies depending on the application, but the preferable lower limit is 500 nm and the preferable upper limit is 100 μm. If the particle diameter of the bell structure particles of the present invention is less than 500 nm, the mass of the core fine particles becomes too small, and it may be difficult to consume sufficient kinetic energy. When the particle diameter of the bell structure particles of the present invention exceeds 100 μm, the physical properties of the vibration control material using the bell structure particles of the present invention are greatly affected by the bell structure particles, and the mechanical strength may be lowered. The more preferable lower limit of the particle diameter of the bell structure particles of the present invention is 1 μm, and the more preferable upper limit is 50 μm.

The size of the nuclear fine particle is not particularly limited as long as it is smaller than the shell, but in order to exert sufficient vibration and sound damping capability, the nuclear fine particle can freely move within the shell pores. It is important to be able to exercise. On the other hand, even if the nuclear fine particles are too small as compared with the holes of the shell, sufficient ability to attenuate vibration and sound cannot be exhibited. The volume of the core fine particles (in the case of two or more, the total volume of all the core fine particles) is preferably 5 to 50% of the volume of the vacancies in the shell body in which the core fine particles are encapsulated. .

The particle diameter of the core fine particles depends on the material (specific gravity) of the core fine particles, but the preferable lower limit is 100 nm and the preferable upper limit is 95 μm. When the particle diameter of the nuclear fine particles is less than 100 nm, the mass of the nuclear fine particles becomes too small, and it may be difficult to consume sufficient kinetic energy. If the particle diameter of the above-mentioned core fine particle exceeds 95 μm, the particle diameter of the bell structure particle has to be increased in order to exhibit sufficient ability to attenuate vibration and sound, and the control using the bell structure particle of the present invention is inevitable. The physical properties of the seismic material are greatly affected by the bell structure particles, and the mechanical strength may decrease.

The thickness of the shell is not particularly limited, and may be appropriately selected according to the purpose of use. The preferable lower limit is 100 nm, and the preferable upper limit is 5 μm. If the thickness of the shell is less than 100 nm, the shell may be broken during kneading into the binder resin or due to vibration of the core fine particles. If the thickness of the shell exceeds 5 μm, the particle size and mass of the tin structure particles will increase. Therefore, in order to exhibit a sufficient vibration control function, a large amount of bell structure particles must be added to the vibration control body. No longer.

The bell structure particles of the present invention can be produced, for example, by the following two production methods.
The first production method is a method for producing the bell structure particles of the present invention in which one core fine particle is encapsulated in the pores of the shell.
The second production method is a method for producing the bell structure particles of the present invention in which two or more nuclear fine particles are encapsulated in the pores of the shell.
These manufacturing methods are also one aspect of the present invention. Below, the manufacturing method of the bell structure particle | grains of this invention is demonstrated in detail.

The first production method includes a step of preparing a coated particle by coating one inorganic fine particle with a resin, a step of preparing a double-coated particle by further coating the coated particle with an inorganic material, and the double It is a manufacturing method of a bell structure particle which has a process of heating covering particles.

In the first method for producing bell-shaped particles, first, a step of preparing coated particles by coating one inorganic fine particle with a resin.
The inorganic fine particles are to be core fine particles in the resulting bell structure particles of the present invention.

The resin is not particularly limited as long as it burns and decomposes under air, nitrogen, and argon, and examples thereof include polystyrene resin, acrylic resin, vinyl ester resin, acetal resin, cellulose derivative, and epoxy resin. These resins may be used alone or in combination of two or more.
Among these, resins mainly composed of polystyrene, polymethyl methacrylate, polyisobutyl methacrylate, and t-butyl polymethacrylate that depolymerize and vaporize at a relatively low temperature are preferable.

The method for preparing the coated particles by coating the inorganic fine particles with a resin is not particularly limited, and examples thereof include a method using an interfacial polymerization method, a method using a graft polymerization method, and a method using heteroaggregation.
In addition, when a relatively thick resin layer is required, after forming a seed layer on the surface of the inorganic fine particles by each of the above methods and absorbing the polymerizable monomer that is a raw material of the resin in the seed layer, A seed polymerization method in which the polymerizable monomer is polymerized to form a thick resin layer is also suitable. As the seed layer, a polymer compound that can absorb the polymerizable monomer is used.

In the first method for producing the bell structure particles, a step of preparing double coated particles by further coating the coated particles with an inorganic material is performed. The coating layer made of the inorganic material is a shell in the resulting bell structure particles of the present invention.

The method for preparing the double coated particles by further coating the coated particles with an inorganic material is not particularly limited, and for example, an interfacial sol-gel method, plating, or the like can be used.
When silicon oxide (silica) or titanium oxide (titania), which is a relatively hard and highly durable material, is used as the inorganic material, the interfacial sol-gel method is preferably used.
Furthermore, in order to form a relatively thick shell layer, a method in which the powder of the inorganic material is accumulated on the surface of the coated particles by a heteroaggregation method or a mechanochemical method, and then a sol-gel method or a plating method is also suitable.

In the manufacturing method of the first bell structure particles, the step of heating the double-coated particles is then performed. The coating layer made of the resin is decomposed by heating, and the coating layer made of the inorganic material is sintered. Thereby, the bell structure particles of the present invention are formed.
The said temperature is more than the decomposition temperature of the used resin, and more than the temperature which sinters the coating layer which consists of the said inorganic material. For example, when the coating layer made of resin is polymethyl methacrylate and the coating layer made of an inorganic material is silicon oxide, the depolymerization temperature of polymethyl methacrylate is 300 ° C. or higher, and the sintering temperature of silicon oxide is 500 ° C. or higher. It is. Therefore, when the heating temperature is 500 ° C. or higher, the coating layer made of the resin can be decomposed and the coating layer made of the inorganic material can be sintered.

The second production method includes a step of preparing resin particles containing a plurality of inorganic fine particles, a step of coating the resin particles with an inorganic material to prepare coated particles, and a step of heating the coated particles. This is a method for producing bell structure particles.

In the second bell structure particle manufacturing method, first, a step of preparing resin particles containing a plurality of inorganic fine particles is performed.
About the said inorganic fine particle and resin, it is the same as that of the manufacturing method of the 1st bell structure particle.

The method for preparing the resin particles containing a plurality of the above-mentioned inorganic fine particles is not particularly limited. For example, the composite particles are prepared by suspension polymerization, emulsion polymerization, etc. of the polymerizable monomer and inorganic particles used as the raw material of the resin. A method of compounding the polymerizable monomer and inorganic particles by bulk polymerization or solution polymerization and pulverizing, or a method of coacervation, phase inversion emulsification, A method of compounding by a drying method, a granulation method, or the like is used. Furthermore, wet or dry classification may be performed in order to make the particle diameter uniform. In order to obtain true spherical resin particles, suspension polymerization, emulsion polymerization, coacervation, phase inversion emulsification, and submerged drying are preferably used.

In the second method for producing the bell structure particles, a step of coating the resin particles with an inorganic material to prepare coated particles is then performed. The coating layer made of the inorganic material is a shell in the resulting bell structure particles of the present invention.

A method for preparing the coated particles by coating the resin particles with an inorganic material is not particularly limited, and for example, an interfacial sol-gel method, plating, or the like can be used.
When silicon oxide (silica) or titanium oxide (titania), which is a relatively hard and highly durable material, is used as the inorganic material, the interfacial sol-gel method is preferably used.
Furthermore, in order to form a relatively thick shell layer, a method in which the inorganic material powder is heteroaggregated on the surface of the coated particles and then a sol-gel method or a plating method is also suitable.

In the second bell structure manufacturing method, the step of heating the coated particles is then performed. The resin is decomposed by heating, and the coating layer made of the inorganic material is sintered. Thereby, the bell structure particles of the present invention are formed.
The said temperature is more than the decomposition temperature of the used resin, and more than the temperature which sinters the coating layer which consists of the said inorganic material.

The bell structure particles of the present invention are used for various applications by taking advantage of their excellent sound absorption, sound insulation and vibration control. For example, it is suitable as a part for automobiles, airplanes, trains, home appliances, electronic devices, structural materials, and soundproofing materials.

According to the present invention, it is possible to provide bell structure particles that are less restricted in production, excellent in heat resistance, and high in ability to attenuate vibrations and sounds.

It is a schematic diagram showing an example of the bell structure particle of the present invention in which one core fine particle is encapsulated in the pores of the shell. It is a schematic diagram showing an example of the bell structure particle | grains of this invention which encloses two or more nuclear fine particles in the void | hole of a shell.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
Hydrophobic surface is obtained by dispersing 20 g of silica particles having a particle size of 450 nm (manufactured by Nissan Chemical Co., Ltd., MP-4540M) in 100 mL of ethanol and adding 2 g of 3-methacryloylpropyltrimethoxysilane, followed by stirring at 70 ° C. for 12 hours. Silica particles were obtained.
After 10 g of the obtained surface hydrophobized silica particles were dispersed in an 80% ethanol aqueous solution, 10 g of styrene and 0.1 g of azobisisobutyronitrile were added, and dispersion polymerization was performed at 70 ° C. in a nitrogen atmosphere. Silica particles (coated particles) having a film (styrene resin layer) containing styrene resin as a main component were obtained.
The thickness of the styrene resin layer in the obtained coated particles was about 200 nm.

The obtained coated particles were dispersed in 200 g of 80% ethanol aqueous solution, and after adding 28 g-ammonia water 1 g, 100 g of 20% tetraethoxysilane-ethanol solution was added dropwise over 12 hours to cause sol-gel reaction. Double-coated particles having a silica layer formed on the surface of the particles were obtained.
The thickness of the silica layer that is the outermost layer of the obtained double-coated particles was about 150 nm.

The obtained double-coated particles are heated in an electric furnace at 500 ° C. for 3 hours to decompose the methyl methacrylate resin and sinter the outermost silica layer. The bell structure particles 1 in which the core particles were encapsulated were obtained.
The resulting bell structure particle 1 had a particle size of 1.1 μm.

(Example 2)
After 10 g of silica particles having a particle diameter of 5 μm (Micropearl SI, manufactured by Sekisui Chemical Co., Ltd.) are dispersed in an 80% ethanol aqueous solution, 1 g of styrene and 0.01 g of azobisisobutyronitrile are added, and the atmosphere is 70 under a nitrogen atmosphere. Silica particles having a styrene resin thin film (seed layer) on the surface were obtained by dispersion polymerization at ° C.
The obtained silica particles having a seed layer are washed, dispersed in a 1% sodium lauryl sulfate aqueous solution, 10 g of styrene and 0.01 g of benzoyl peroxide are added, stirred at room temperature for 24 hours, and further at 70 ° C. for 12 hours. By carrying out seed polymerization, silica particles (coated particles) having a film (styrene resin layer) containing styrene resin as a main component on the surface were obtained.
The thickness of the styrene resin layer in the obtained coated particles was about 1 μm.

The obtained coated particles were dispersed in a 20% ethanol aqueous solution, silica particles having a particle diameter of 450 nm (manufactured by Nissan Chemical Co., Ltd., MP-4540M) were added, and heteroaggregated on the surface of the styrene resin layer. After washing with water, dispersing in 200 g of 80% ethanol aqueous solution, adding 1 g of 28% -ammonia water, and then dropping 100 g of 20% tetraethoxysilane-ethanol solution over 12 hours to cause sol-gel reaction, the surface of the coated particles Double-coated particles having a silica layer formed thereon were obtained.
The thickness of the silica layer which is the outermost layer of the obtained double-coated particles was about 0.5 μm.

The obtained double-coated particles are heated in an electric furnace at 500 ° C. for 3 hours to decompose the styrene resin and sinter the outermost silica layer. The bell structure particles 2 containing the particles were obtained.
The resulting bell structure particle 2 had a particle size of 8.0 μm.

(Example 3)
Surface dispersion is made by dispersing 10 g of silica particles having a particle size of 200 nm (manufactured by Nissan Chemical Co., MP-2040) in 100 mL of ethanol and adding 1 g of 3-methacryloylpropyltrimethoxysilane, followed by stirring at 70 ° C. for 12 hours. Silica particles were obtained.
After uniformly dispersing 10 g of methyl methacrylate, 5 g of surface hydrophobized silica particles, and 0.01 g of azobisisobutyronitrile, the mixture was suspended in 1000 g of a 5% polyvinylpyrrolidone K30 aqueous solution with stirring at 200 rpm. By polymerizing at a temperature of 12 ° C. for 12 hours, methyl methacrylate resin particles containing a plurality of silica particles were obtained. The average particle diameter of the resulting methyl methacrylate resin particles encapsulating silica particles was about 10 μm.

Silica particle-encapsulated methyl methacrylate resin particles obtained are dispersed in a 20% ethanol aqueous solution, silica particles having a particle size of 450 nm (manufactured by Nissan Chemical Co., Ltd., MP-4540M) are added, and heteroaggregated on the surface of the methyl methacrylate resin particles. It was. After washing with water, dispersing in 200 g of a 0% ethanol aqueous solution, adding 1 g of 28% -ammonia water, then dropping 150 g of a 20% tetraethoxysilane-ethanol solution over 12 hours and causing a sol-gel reaction, the methacrylic silica containing silica particles Coated particles in which a silica layer was formed on the surfaces of the acid methyl resin particles were obtained.
The thickness of the silica layer which is the outermost layer of the obtained coated particles was about 0.8 μm.

The obtained coated particles are heated in an electric furnace at 500 ° C. for 3 hours to decompose the methyl methacrylate resin and to sinter the outermost silica layer, so that a plurality of nuclei are contained in the holes of the shell. Bell structure particles 3 in which fine particles were encapsulated were obtained.
The resulting bell structure particle 3 had a particle size of 11.5 μm.

(Evaluation)
Polypropylene resin ("LA880" manufactured by Mitsui Chemicals, Inc.) is plastmilled at 200 ° C, and the bell structure particles 1 obtained in Example 1, the bell structure particles 2 obtained in Example 2, and the example 3 The bell structure particles 3 and silica particles having a particle diameter of 10 μm as Comparative Example 1 were added in an amount of 40% by weight and kneaded for 60 seconds. The obtained kneaded material was heated and pressed at 180 ° C. for 1 minute using a heating press apparatus to prepare a resin plate having a length of 300 mm, a width of 2.5 mm, and a thickness of 5 mm.
In addition, as Reference Example 1, a resin plate made only of a polypropylene resin without adding soundproof particles was also produced.

The resin plates according to each of the examples, comparative examples, and reference examples were measured with a loss factor measuring instrument (RION sound and vibration signal analyzer SA-74) manufactured by Lion under an environment of 20 ° C. (Η) was measured.
The results are shown in Table 1.
In addition, if the numerical value of loss factor ((eta)) is 0.1 or more, it can generally be said that it has sufficient performance as a soundproof member.

According to the present invention, it is possible to provide bell structure particles that are less restricted in production, excellent in heat resistance, and high in ability to attenuate vibrations and sounds.

1 Bell structure particle that encloses one core particle in a shell hole 1 'Bell structure particle that includes two or more core particles in a shell hole 2 Shell body 3 Core particle book

Claims (4)

A step of preparing a coated particle by coating one inorganic fine particle with a resin, a step of preparing a double-coated particle by further coating the coated particle with an inorganic material, and heating the double-coated particle to A method for producing bell-structured particles having a step of decomposing a coating layer made of a resin ,
The inorganic fine particles and the inorganic material are metals of 4 to 14 metals, alloys containing 4 to 14 metals, 4 to 14 metals or oxides of alloys, 4 to 14 metals or alloys of nitrides, or 4 to 14 metal or alloy carbides,
The resin burns and decomposes under air, nitrogen and argon,
The step of heating the double-coated particles to decompose the coating layer made of the resin is performed by heating at a temperature equal to or higher than the decomposition temperature of the resin and the temperature for sintering the coating layer made of the inorganic material. A method for producing bell-structured particles, characterized in that it is performed . A bell having a step of preparing resin particles containing a plurality of inorganic fine particles, a step of coating the resin particles with an inorganic material to prepare coated particles, and a step of heating the coated particles to decompose the resin A method for producing structured particles, comprising:
The inorganic fine particles and the inorganic material are metals of 4 to 14 metals, alloys containing 4 to 14 metals, 4 to 14 metals or oxides of alloys, 4 to 14 metals or alloys of nitrides, or 4 to 14 metal or alloy carbides,
The resin burns and decomposes under air, nitrogen and argon,
The step of decomposing the resin by heating the coated particles is performed by heating at a temperature equal to or higher than a decomposition temperature of the resin and a temperature equal to or higher than a temperature at which the coating layer made of the inorganic material is sintered. A method for producing bell structure particles characterized by the above. The inorganic material is silicon oxide or titanium oxide, and the resin contains polystyrene, polymethyl methacrylate, polyisobutyl methacrylate, or t-butyl polymethacrylate, and the double-coated particles are heated to The method for producing bell-structured particles according to claim 1, wherein heating is performed to 500 ° C or higher in the step of decomposing the coating layer made of resin. The inorganic material is silicon oxide or titanium oxide, and the resin contains polystyrene, polymethyl methacrylate, polyisobutyl methacrylate, or t-butyl polymethacrylate, and decomposes the resin by heating the coated particles. The method for producing bell structure particles according to claim 2, wherein heating is performed to 500 ° C or higher in the step of performing.

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