Thermoplastic resin composition

Abstract

To provide a new thermoplastic resin composition excellent in vibration-damping properties and a method for producing the same, an additive for improving vibration-damping properties of a thermoplastic resin, and a vibration-damping material containing the thermoplastic resin composition.SOLUTION: A thermoplastic resin composition contains composite particles in which a thermoplastic resin and polymer graft chain are bonded to each other on the surface of the particles.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic resin composition and a method for producing the same, an additive for improving the vibration-damping properties of a thermoplastic resin, and a vibration-damping material containing the thermoplastic resin composition. [Background technology]

[0002] In recent years, there has been a growing demand for vibration control measures for various types of equipment, particularly in fields such as automobiles, home appliances, and precision instruments. Generally, highly vibration-damping materials include composite materials such as metal plates bonded to vibration-absorbing materials such as rubber or asphalt, or composite materials such as vibration-damping steel plates, which sandwich a vibration-absorbing material between metal plates. These vibration-damping materials maintain their shape with highly rigid metal plates and absorb vibrations with a vibration-absorbing material. Metal-only alloy materials also exist, which utilize twin crystals or ferromagnetism to convert kinetic energy into thermal energy to absorb vibrations. However, composite materials have limitations in formability due to the bonding of different materials, and the use of metal steel plates results in heavy products. Furthermore, alloy materials, which are made solely of metal, are heavy and lack sufficient vibration-damping performance.

[0003] In response to such conventional techniques, functional resin compositions with vibration-damping properties have been proposed. For example, Patent Document 1 discloses a vibration-damping molded resin article obtained by molding a polypropylene-based resin composition in which a reinforcing inorganic filler is blended with a resin component in which high-density polyethylene (PE) and an aromatic hydrocarbon resin are added and mixed with crystalline polypropylene (PP), characterized in that the resin composition further contains a hydrogenated product of an aromatic vinyl-conjugated diene block copolymer as a resin component. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-331329 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention relates to a new thermoplastic resin composition having excellent vibration-damping properties, a method for producing the same, an additive for improving the vibration-damping properties of thermoplastic resins, and a vibration-damping material containing the thermoplastic resin composition. [Means for solving the problem]

[0006] The present invention relates to the following [1] to [4]. [1] A thermoplastic resin composition comprising a thermoplastic resin and composite particles having polymer graft chains bonded to the particle surface. [2] A method for producing a thermoplastic resin composition, comprising the step of melt-kneading a thermoplastic resin and composite particles having polymer graft chains bonded to the particle surface. [3] An additive for improving the vibration damping properties of thermoplastic resins, comprising composite particles with polymer graft chains bonded to the particle surface. [4] A vibration-damping material comprising the thermoplastic resin composition according to [1], which comprises a thermoplastic resin and composite particles having polymer graft chains bonded to the particle surface. [5] A vibration-damping material comprising a thermoplastic resin and composite particles having polymer graft chains bonded to the particle surface. [6] A method for producing a vibration-damping material, comprising the step of melt-kneading a thermoplastic resin with composite particles having polymer graft chains bonded to the particle surface. [7] Use of composite particles having polymer graft chains bonded to the particle surface to improve the vibration damping properties of thermoplastic resins. [8] A method for improving the vibration damping properties of thermoplastic resins using composite particles with polymer graft chains bonded to the particle surface. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a new thermoplastic resin composition having excellent vibration-damping properties, a method for producing the same, an additive for improving the vibration-damping properties of a thermoplastic resin, and a vibration-damping material containing the thermoplastic resin composition. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present inventors have newly discovered that vibration-damping properties can be improved by forming some kind of bond between the elastomer and filler added to a thermoplastic resin composition and strengthening the interface between them. While the mechanism is unclear, it is believed that strengthening the interface between the elastomer and filler increases the strain energy in the elastomer. The present inventors have also newly discovered that excellent vibration-damping properties can be achieved by using composite particles in which an elastomer and a filler are bonded together, which are obtained by the grafting-from method, in which polymer graft chains corresponding to the elastomer are polymerized from polymerization initiation points on the surface of the particles used as the filler. It is believed that this is because the grafting-from method significantly strengthens the interface between the elastomer and filler by bonding the polymer graft chains to the particle surface at a high density.

[0009] [Thermoplastic resin composition] The thermoplastic resin composition of the present invention contains a thermoplastic resin and composite particles having polymer graft chains bonded to the particle surface.

[0010] [Thermoplastic resin] Examples of thermoplastic resins include polyolefin resins, polyester resins, polyamide resins, ABS resins, polystyrene resins, polycarbonate resins, vinyl chloride resins, acrylic resins, etc. Among these, from the viewpoint of ease of handling of the resulting resin composition, such as moldability, preferably one or more resins selected from the group consisting of polyolefin resins, polyamide resins, and ABS resins, more preferably one or more resins selected from the group consisting of polyolefin resins, and even more preferably polypropylene resin.

[0011] The mass average molecular weight of the thermoplastic resin is not particularly limited, but those having a mass average molecular weight of 5,000 to 500,000 can be used.

[0012] The amount of thermoplastic resin in the thermoplastic resin composition of the present invention is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more, from the viewpoint of obtaining a molded article or vibration-damping material exhibiting the desired elastic modulus. On the other hand, from the viewpoint of obtaining a molded article or vibration-damping material exhibiting the desired vibration-damping properties, it is preferably 95% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less. When two or more thermoplastic resins are blended, the blending amount is the total amount of the thermoplastic resins.

[0013] [Composite particles] Composite particles have polymer graft chains bonded to their surfaces. Known fillers can be used as the particles, including metal oxides, metal oxide salts, metal hydroxides, metal carbonates, and cellulose. Preferably, the filler is one or more selected from the group consisting of metal oxides, metal oxide salts, metal hydroxides, and metal carbonates. More preferably, the filler is one or more selected from the group consisting of silicon oxides such as silica, and silicates such as mica and talc. Silica is even more preferred. The shape of the particles is not particularly limited, and examples include plate-like, granular, needle-like, and fibrous shapes. In this specification, the term "particle" refers to particles used in the production of composite particles. Examples of polymer graft chains include homopolymers or copolymers of styrene-based monomers, nitrile-based monomers, (meth)acrylic monomers, unsaturated olefins, conjugated diene-based monomers, etc., and from the viewpoint of obtaining molded articles and vibration-damping materials that exhibit the desired vibration-damping properties, they are preferably one or more homopolymers or copolymers selected from the group consisting of acrylic acid, methacrylic acid, and derivatives thereof, more preferably one or more homopolymers or copolymers selected from methacrylic acid and its derivatives, and even more preferably polybutyl methacrylate. From the viewpoint of obtaining molded articles and vibration-damping materials that exhibit the desired vibration-damping properties, the bond is preferably a chemical bond, and even more preferably a covalent bond.

[0014] The glass transition temperature (Tg) of the polymer graft chain in the composite particle is preferably -30°C or higher, more preferably -10°C or higher, even more preferably 10°C or higher, and even more preferably 25°C or higher from the viewpoint of vibration damping property development, and from the same viewpoint, it is preferably 80°C or lower, more preferably 50°C or lower, and even more preferably 40°C or lower. Furthermore, the polymer graft chain in the composite particle may have two or more glass transition temperatures (Tg), or may have a Tg other than a Tg of -30°C or higher and 80°C or lower. The glass transition temperature (Tg) of the polymer graft chain in the composite particle can be controlled by the monomer, molecular weight, and molecular weight distribution used in the production of the composite particle. For example, in the case of composite particles, it is known that Tg increases when the graft density increases and the polymer chain becomes an extended chain. In such a case, Tg can be controlled by adjusting the graft density. In the temperature range around Tg, the viscoelasticity tan δ of the resin becomes maximum, which is effective in developing vibration damping property, and controlling Tg allows the desired temperature The glass transition temperature (Tg) can be measured by the method described in the Examples below.

[0015] The graft density of the polymer graft chains in the composite particles is preferably 0.001 chains / nm from the viewpoint of increasing the strain energy in the elastomer. 2 More preferably, 0.01 chains / nm 2 More preferably, 0.1 chains / nm or more 2 On the other hand, from the viewpoint of ease of grafting of polymer chains, it is preferable to have 5 chains / nm 2 Less than or equal to 3 chains / nm, more preferably 2 More preferably, 1 chain / nm or less 2 More preferably, 0.3 chains / nm or less 2 The graft density is measured by the method described in the Examples below.

[0016] The thickness of the polymer graft chains in the composite particles is preferably 1 nm or more, more preferably 3 nm or more, and even more preferably 5 nm or more, from the viewpoint of efficiently increasing the strain energy in the elastomer. From the same viewpoint, the thickness is preferably 1 μm or less, more preferably 100 nm or less, even more preferably 40 nm or less, and even more preferably 15 nm or less. The thickness of the polymer graft chains is calculated by the method described in the Examples below.

[0017] The number average molecular weight of the polymer graft chains in the composite particles is preferably 10,000 or more, more preferably 20,000 or more, and even more preferably 30,000 or more, from the viewpoint of controlling the film thickness of the polymer graft chains. From the same viewpoint, it is preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 200,000 or less. The number average molecular weight of the polymer graft chains is measured by the method described in the Examples below.

[0018] The amount of composite particles in the thermoplastic resin composition of the present invention is preferably 1% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and even more preferably 25% by mass or more, from the viewpoint of exhibiting vibration-damping properties. On the other hand, from the viewpoint of obtaining a molded product or vibration-damping material exhibiting a desired elastic modulus, it is preferably 75% by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, and even more preferably 50% by mass or less. When two or more types of composite particles are contained, the amount is the total amount of composite particles.

[0019] The amount of composite particles in the thermoplastic resin composition of the present invention is preferably 1 part by mass or more, more preferably 20 parts by mass or more, even more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, per 100 parts by mass of the thermoplastic resin, from the viewpoint of vibration-damping property expression. On the other hand, from the viewpoint of obtaining a molded article or a vibration-damping material exhibiting a desired elastic modulus, it is preferably 300 parts by mass or less, more preferably 200 parts by mass or less, even more preferably 100 parts by mass or less, and even more preferably 90 parts by mass or less. The content of polymer graft chains in the composite particles in the thermoplastic resin composition of the present invention is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the thermoplastic resin, from the viewpoint of vibration-damping property expression. On the other hand, from the viewpoint of obtaining a molded article or a vibration-damping material exhibiting a desired elastic modulus, it is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less.

[0020] The dispersed particle size of the composite particles in the thermoplastic resin composition of the present invention is preferably 10 nm or more, more preferably 100 nm or more, and even more preferably 1 μm or more from the viewpoint of exhibiting vibration-damping properties, and from the same viewpoint, is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 10 μm or less. The composite particles may exist alone or in the form of aggregates. The dispersed particle size of the composite particles is measured by the method described in the Examples below.

[0021] [Method of manufacturing composite particles] Composite particles can be obtained by attaching polymer graft chains to particle surfaces. There are no particular limitations on the method for attaching polymer graft chains to particle surfaces, as long as it is a method that can graft polymer chains. A preferred method is the grafting-from method, in which polymer graft chains are polymerized from polymerization initiation points on the particle surface. The polymerization method is not particularly limited, but examples include radical polymerization, anionic polymerization, and cationic polymerization. Among these, living radical polymerization, living anionic polymerization, and living cationic polymerization are preferred from the viewpoints of ease of control of the molecular weight and molecular weight distribution of the polymer chains and ease of grafting various copolymers. Living radical polymerization is even more preferred from the viewpoint of its applicability to a wide range of monomers. Examples of living radical polymerization methods that can be used include atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer polymerization (RAFT), and nitroxide-mediated living radical polymerization (NMP). From the same viewpoint, atom transfer radical polymerization (ATRP) is preferred.

[0022] More specifically, an example of a method for producing composite particles includes the following step 2, and if necessary, the following step 1 may also be carried out. The following steps 1 and 2 can be carried out under known conditions for living radical polymerization. Step 1: Binding a polymerization initiating group to the particle surface Step 2: A step of contacting particles having polymerization initiation groups on the surface with a monomer under living radical polymerization conditions.

[0023] The particles having polymerization initiating groups on their surfaces in step 2 are not particularly limited as long as they have a binding group that bonds the particle surface to the polymer chain. From the viewpoint of bonding a polymer graft chain to the particle surface, the polymerization initiating group is a living radical polymerization initiating group, preferably an atom transfer radical polymerization initiating group, more preferably a haloacyl group, even more preferably an α-haloacyl group, even more preferably an α-bromoacyl group, and even more preferably a 2-bromoisobutyryl group. Compounds that serve as the raw material for the binding group include compounds having a group that bonds to the particle surface and a polymerization initiating group, and compounds having a group that bonds to the particle surface or a polymerization initiating group. Step 1 includes a step of introducing amino groups or hydroxy groups onto the particle surface and a step of introducing polymerization initiating groups. From the viewpoint of bonding a polymer graft chain to the particle surface, it is preferable to include a step of introducing polymerization initiating groups onto the particle surface after the step of introducing amino groups or hydroxy groups onto the particle surface. The compound used in the step of introducing amino or hydroxyl groups onto the particle surface is a compound having a group that bonds to the particle surface and an amino or hydroxyl group. From the viewpoint of easy availability, it is preferably a silane compound, more preferably an aminoalkylsilane compound, and even more preferably 3-aminopropyltrimethoxysilane. The compound used in the step of introducing polymerization initiating groups onto the particle surface is a compound having a polymerization initiating group and a functional group that reacts with an amino or hydroxyl group. From the viewpoint of bonding a polymer graft chain to the particle surface, it is preferably a haloalkanoic acid derivative, more preferably a bromoalkanoic acid derivative, even more preferably a 2-bromo-2-methylpropionic acid derivative, and even more preferably 2-bromoisobutyl bromide. For example, if the particles originally contain polymerization initiating sites or are formed as a result of surface treatment such as plasma treatment, they will have polymerization initiating groups, so step 1 is not necessary. However, step 1 may be performed when using silica, mica, talc, glass filler, etc. that do not have polymerization initiating groups. Note that, from the viewpoint of adjusting the graft density, in step 1, a silane coupling agent that does not contain polymerization initiating groups may be added to the polymerization initiating group-containing silane coupling agent. In the step 1 of bonding the polymerization initiation groups to the particle surface, a method of dispersing the particles in a dispersion medium is preferred from the viewpoint of preventing the particles from agglomerating.

[0024] The monomer used in step 2 can be a monomer that constitutes a thermoplastic elastomer known as a vibration-damping elastomer. Examples of monomers that constitute such thermoplastic elastomers include styrene-based monomers, nitrile-based monomers, (meth)acrylic monomers, unsaturated olefins, and conjugated diene-based monomers, and other monomers having specific groups on their side chains can also be used. In step 2, the particles having polymerization initiation groups on their surfaces are brought into contact with the monomer under living radical polymerization conditions. In order to prevent aggregation of the particles, monomers, and composite particles, it is preferable to disperse the particles, monomers, and composite particles in a dispersion medium and then polymerize them.

[0025] After polymerization, the composite particles may be optionally purified. In the purification step of the composite particles, a method of dispersing the composite particles in a polymer in a dispersion medium and removing the solvent is preferred from the viewpoint of preventing aggregation of the composite particles. Furthermore, a method of removing the metal catalyst used in the polymerization step is preferred.

[0026] The thermoplastic resin composition of the present invention may contain, as components other than those described above, chain extenders, plasticizers, organic crystal nucleating agents, inorganic crystal nucleating agents, hydrolysis inhibitors, flame retardants, antioxidants, lubricants such as hydrocarbon waxes and anionic surfactants, ultraviolet absorbers, antistatic agents, antifogging agents, light stabilizers, pigments, mildew inhibitors, antibacterial agents, foaming agents, other polymeric materials, and the like.

[0027] [Method of producing thermoplastic resin composition] A method for producing the thermoplastic resin composition of the present invention includes a step of melt-kneading a thermoplastic resin with composite particles having polymer graft chains bonded to the particle surface. For melt-kneading, a known kneading machine such as an internal kneader, a single-screw or twin-screw extruder, or an open-roll kneader can be used. After melt-kneading, the melt-kneaded mixture may be dried or cooled according to a known method. Alternatively, the raw materials may be uniformly mixed in advance using a Henschel mixer, a super mixer, or the like before being subjected to melt-kneading. The melt-kneading temperature and time are not necessarily set depending on the type of raw materials used, but are preferably 170 to 240°C and 15 to 900 seconds.

[0028] In the process of melt-kneading a thermoplastic resin and composite particles having polymer graft chains bonded to their particle surfaces, the amount of composite particles having polymer graft chains bonded to their particle surfaces added is preferably 1 part by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, per 100 parts by mass of the thermoplastic resin, from the viewpoint of exhibiting vibration-damping properties; and from the same viewpoint, is preferably 200 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 90 parts by mass or less.

[0029] [Additives] The additive of the present invention comprises composite particles having polymer graft chains bonded to their surfaces. The additive of the present invention may optionally contain chain extenders, plasticizers, organic crystal nucleating agents, inorganic crystal nucleating agents, hydrolysis inhibitors, flame retardants, antioxidants, lubricants such as hydrocarbon waxes and anionic surfactants, UV absorbers, antistatic agents, antifogging agents, light stabilizers, pigments, mildew inhibitors, antibacterial agents, and foaming agents. Furthermore, the additive of the present invention may contain a portion of the resin (e.g., 0.1 to 50.0 mass% of the additive) that is melt-kneaded with the additive. The additive of the present invention is used as an additive for improving the vibration-damping properties of thermoplastic resins. Therefore, the present invention also discloses a method for using composite particles having polymer graft chains bonded to their surfaces to improve the vibration-damping properties of thermoplastic resins.

[0030] [Vibration-damping materials] The thermoplastic resin composition of the present invention can be suitably used as a vibration-damping material for products such as acoustic equipment, electrical products, buildings, industrial equipment, automobile parts, motorcycle parts, containers, or their parts or housings, by using various molding and processing methods such as injection molding, extrusion molding, and thermoforming.

[0031] For example, when a part or a housing containing the thermoplastic resin composition of the present invention is produced by injection molding, pellets of the thermoplastic resin composition of the present invention are filled into an injection molding machine and then injected into a mold for molding.

[0032] For injection molding, a known injection molding machine can be used. For example, an injection molding machine having a cylinder and a screw inserted therein as main components (J75E-D, J110AD-180H (manufactured by The Japan Steel Works, Ltd.), etc.) can be used. Note that although the raw materials for the thermoplastic resin composition of the present invention may be supplied to a cylinder and melt-kneaded as is, it is preferable to melt-knead the raw materials in advance and then charge the mixture into the injection molding machine.

[0033] Furthermore, when a molding method other than injection molding is used, the molding may be carried out according to a known method, and there are no particular limitations.

[0034] The molded article of the thermoplastic resin composition of the present invention can be suitably used as a vibration-damping material for products such as acoustic equipment, electrical appliances, buildings, industrial equipment, automobile parts, motorcycle parts, containers, etc., or for parts or housings thereof. The application to these can be appropriately determined depending on the manufacturing method, application location, and desired purpose of the parts, housings, devices, and equipment, and can be used in accordance with common methods in the technical field. [Example]

[0035] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples in any way.

[0036] <Glass transition temperature of polymer graft chains in composite particles> Measurement was performed according to the method of JIS K 7121. Using a differential scanning calorimeter (DSC7020 manufactured by Hitachi High-Tech Science), the composite particles were heated from 40°C to 200°C at a rate of 10°C / min. The midpoint glass transition temperature Tmg (°C) was determined as the temperature at the point where a line equidistant along the vertical axis from the extended line of each baseline intersects with the curve of the step-like change in the glass transition in the DSC thermogram.

[0037] <Number average molecular weight of polymer graft chains in composite particles> The number-average molecular weight of the polymer graft chains in the composite particles was measured by measuring the number-average molecular weight of the polymer chains not bonded to the composite particles, which were simultaneously produced during the composite particle production process. The number-average molecular weight was measured by gel permeation chromatography (GPC) using a GMHHR-H + GMHHR-H (cation) column, chloroform as the solvent, a flow rate of 1.0 mL / min, and a column temperature of 40°C, using polystyrene as the molecular weight standard.

[0038] <Graft density of polymer chains in composite particles> Graft density (chains / nm 2 ) was calculated by measuring the graft amount (W) and the number average molecular weight (Mn) of the graft chains and using the following formula. The graft amount was calculated by thermal weight loss measurement (TG). More specifically, the temperature was raised from 40°C to 500°C at a rate of 10°C / min in the atmosphere, and the weight loss rate was measured. The number average molecular weight of the graft chains was calculated by the gel permeation chromatography (GPC) method shown below. Graft density (chains / nm 2 ) = graft amount (g / nm 2 ) / number average molecular weight of grafted chains × (Avogadro's number)

[0039] <Film thickness of polymer graft chains in composite particles> The film thickness was calculated using the following formula: The polymer density of the polymer chains not bonded to the composite particles, which are simultaneously produced in the process of producing the composite particles, was taken as the polymer density of the polymer graft chains. It was measured by the pycnometer method in accordance with JIS K 7112.

[0040]

number

[0041] <Dispersion particle size of composite particles> The fracture surface of a test piece of the composite particles in the thermoplastic resin was observed using a scanning electron microscope (SEM). From the SEM image, the cross sections of 30 composite particles were selected, and the major axis of each was visually read, and the average value was taken as the dispersed particle size. conditions Equipment: Field emission scanning electron microscope (S-4000, Hitachi, Ltd.) Acceleration magnification: 10kV Spot diameter: 8mm Magnification: 400x~5000x

[0042] [Preparation of Composite Particle 1] a) A step of bonding a polymerization initiating group to the particle surface a-1) Introduction of amino groups onto the surface of silica particles 40 g of silica microparticles (SILFIL NSS-3N, manufactured by Tokuyama Corporation, average particle size 120 nm) and 2 g of 3-aminopropyltrimethoxysilane (KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to 200 mL of ethanol. The mixture was stirred at room temperature for 12 hours. After washing with ethanol, the silica microparticles were collected using a centrifuge and then heated at 110°C for 1 hour to obtain amino-group-introduced silica microparticles.

[0043] a-2) Introduction of polymerization initiation groups onto the surface of amino group-introduced silica particles 40 g of the above amino group-introduced silica microparticles, 200 mL of anhydrous THF, 1 mL of anhydrous triethylamine (Tokyo Chemical Industry Co., Ltd.), and 1 mL of 2-bromoisobutyl bromide (BIBB, Tokyo Chemical Industry Co., Ltd.) were placed in a 500 mL eggplant-shaped flask and stirred at room temperature for 2 hours. After that, the mixture was washed with THF and methanol, and the polymerization initiator group-introduced silica microparticles with 2-bromoisobutyryl groups introduced as polymerization initiator groups were recovered by centrifugation and stored as a polymerization initiator group-introduced silica microparticle methanol solution.

[0044] b) contacting particles having polymerization initiation groups on their surfaces with a monomer under living radical polymerization conditions; A 500 mL eggplant-shaped flask was charged with a methanol solution containing 40 g of the prepared silica microparticles with polymerization initiator groups, 160 mL of methanol, 40 mL of water, and 35 g of butyl methacrylate (Tokyo Chemical Industry Co., Ltd.), followed by 1 hour of nitrogen bubbling. A methanol solution prepared by stirring 11 mg of Cu(II)Br (Tokyo Chemical Industry Co., Ltd.) and 90 mg of pentamethyldiethylenetriamine (Tokyo Chemical Industry Co., Ltd.) in 2 mL of methanol was then added. After thorough stirring, a 90 mg aqueous solution of ascorbic acid (Tokyo Chemical Industry Co., Ltd.) was added to initiate polymerization. The mixture was then heated to 40°C and stirred for 4 hours. The silica microparticles grafted with polybutyl methacrylate were then washed with methanol and collected by centrifugation. The polymer graft chain content was 35.5% by mass.

[0045] [Preparation of Composite Particle 2] b) contacting particles having polymerization initiation groups on their surfaces with a monomer under living radical polymerization conditions; A 500 mL eggplant-shaped flask was charged with an anisole solution containing 40 g of silica microparticles with polymerization initiator groups (prepared in step a) of the preparation of Composite Particles 1), 20 mL of anisole, and 60 g of butyl methacrylate (Tokyo Chemical Industry Co., Ltd.). The mixture was heated to 60°C, thoroughly stirred, and then nitrogen bubbling was performed for 1 hour. Then, an anisole solution prepared by stirring 144 mg of Cu(I)Br (Tokyo Chemical Industry Co., Ltd.) and 346 mg of pentamethyldiethylenetriamine (Tokyo Chemical Industry Co., Ltd.) in 2 mL of anisole was added to initiate polymerization. The mixture was then stirred for 10 hours. The resulting mixture was then dispersed in chloroform, washed with methanol and aqueous ammonia, and solvent-dried to obtain silica microparticles grafted with polybutyl methacrylate. The polymer graft chain content was 32.0% by mass.

[0046] [Preparation of Composite Particle 3] Composite particles were prepared in the same manner as Composite Particle 2, except that the amount of silica microparticles added was 6 g, the amount of anisole added was 60 mL, the amount of butyl methacrylate added was 180 g, the polymerization temperature was 80°C, the amount of Cu(I)Br stirred in 2 mL of anisole was 431 mg, the amount of pentamethyldiethylenetriamine was 1040 mg, and the polymerization time was 5 minutes.

[0047] [Preparation of Composite Particle 4] Composite particles were prepared in the same manner as Composite Particle 3, except that the polymerization time was changed to 15 minutes.

[0048] [Preparation of Composite Particle 5] Composite particles were prepared in the same manner as in Composite Particle 3, except that the polymerization time was changed to 30 minutes.

[0049] [Preparation of Composite Particle 6] Composite particles 2 were prepared in the same manner as Composite particles 2, except that the amount of silica fine particles added was changed to 20 g, the amount of anisole added to 3 mL, the amount of butyl methacrylate added to 100 g, and the polymerization temperature to 80°C.

[0050] [Preparation of Composite Particle 7] Composite particles were prepared in the same manner as in Composite Particles 3, except that the silica fine particles were changed to Nipsil AQ and the polymerization time was changed to 20 minutes.

[0051] [Preparation of Composite Particle 8] Composite particles were prepared in the same manner as in Composite Particle 3, except that the silica fine particles were replaced with mica fine particles A-21S and the polymerization time was changed to 20 minutes.

[0052] [Preparation of Composite Particle 9] Composite particles were prepared in the same manner as composite particles 3, except that the amount of silica microparticles added was 12 g, the amount of Cu(I)Br added was 861 mg, the amount of pentamethyldiethylenetriamine added was 2080 mg, the polymerization time was 10 minutes, and butyl methacrylate was replaced with hexyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.).

[0053] [Preparation of Thermoplastic Resin Composition] Examples 1 to 3, Comparative Example 1 c) Melting and kneading the composite particles with a thermoplastic resin Using a Laboplastomill (manufactured by Toyo Seiki Seisakusho, Ltd.), the components shown in Table 1 were blended in the amounts shown in Table 1 and melt-kneaded at 200°C to obtain a thermoplastic resin composition.

[0054] Examples 4 to 13, 15 to 17 Thermoplastic resin compositions were obtained in the same manner as in Examples 1 to 3, except that the formulations were changed as shown in Tables 2 and 3.

[0055] Example 14 Thermoplastic resin compositions were obtained in the same manner as in Examples 1 to 3, except that the formulation was changed as shown in Table 3, the melt-kneading temperature was changed to 240°C, the melting temperature for press molding was changed to 240°C, and the cooling temperature was changed to 80°C.

[0056] <Loss coefficient> Using an automatic press molding machine (Toyo Seiki Seisakusho), the material was melted at 200°C and cooled to 30°C to form loss factor test specimens (127 mm × 12.7 mm × 1.6 mm). The loss factor was calculated from the second-order resonance peak of the frequency response function measured using the central excitation method based on JIS K7391 using the half-width method. A system consisting of a Type 3160 oscillator, a Type 2718 amplifier, a Type 4810 exciter, and a Type 8001 acceleration sensor (all manufactured by B&K) was used, along with the loss factor measurement software MS18143. The measurement environment was controlled by a thermostatic chamber (Espec Corporation, PU-3J), and measurements were performed over a temperature range from 0°C to 80°C. The results at 20°C and 80°C are shown in Tables 1 to 3.

[0057] [Table 1]

[0058] [Table 2]

[0059] [Table 3]

[0060] Details of each component shown in Tables 1 to 3 are as follows. Polypropylene: MA03 (Japan Polypropylene) PBMA: Polybutyl methacrylate (Sigma-Aldrich) SiO2: SILFIL NSS-3N (Tokuyama Corporation) GF:T-480 (manufactured by Nippon Electronic Glass Co., Ltd.) Composite particle 7 SiO2: Nipsil AQ (Tosoh Silica Corporation) Composite particle 8: Mica A-21S (Yamaguchi Mica Co., Ltd.) Polyamide: Amilan CM1017 (Toray Industries, Inc.) ABS: Toyolac 7000-314 (Toray Industries)

[0061] The thermoplastic resin compositions of Example 3 and Comparative Example 1 were injection molded and subjected to the following plate vibration test, fan vibration test, and fan rotation noise test. The results are shown in Tables 4 and 5.

[0062] <Plate vibration test> The thermoplastic resin compositions of Example 3 and Comparative Example 1 were injection molded using an injection molding machine (J11AD-180H, manufactured by Japan Steel Works, Ltd.) to mold flat plate test specimens (100 mm × 100 mm × 2 mm). The cylinder temperatures were set at 200 °C for the first five units from the nozzle tip, 170 °C for the remaining unit, and 45 °C below the hopper. The mold temperature was set at 50 °C. For the vibration test, a system consisting of a Type 3160 oscillator, a Type 2718 amplifier, a Type 4810 vibrator, a Type 8001 acceleration sensor, and a 4189-A-029 sound level meter (all manufactured by B&K) was used. The center of the molded flat plate was attached to a contact tip and fixed to the acceleration sensor, and then random vibration was applied. The vibration level was calculated from the ratio of the vibration acceleration detected by the acceleration sensor to the vibration force in the range of 20 Hz to 12,000 Hz. Additionally, the noise level was calculated from the ratio of the sound pressure detected by a sound level meter at a height of 100 mm at the center of the plate to the excitation force. The measurement environment was controlled at 20°C or 80°C in a thermostatic chamber (PU-3J, manufactured by Espec Corporation). A smaller value indicates greater reduction in vibration and noise.

[0063] <Fan vibration test> The thermoplastic resin compositions of Example 3 and Comparative Example 1 were injection molded using an injection molding machine (SE180D manufactured by Sumitomo Heavy Industries, Ltd.) to produce plate fan molded articles with the same shape as a plate fan manufactured by Fantech Co., Ltd. (PLF125-18, 150 mm diameter, 8 blades). The cylinder temperatures were set at 200°C for the first five units from the nozzle tip, 170°C for the remaining unit, and 45°C below the hopper. The mold temperature was set at 50°C. For vibration testing, a system consisting of a Type 3160 oscillator, a Type 2718 amplifier, a Type 4810 vibrator, a Type 8001 acceleration sensor, and a 4189-A-029 sound level meter (all manufactured by B&K) was used. The center of the plate fan was attached to a contact tip and fixed to the acceleration sensor, and random vibration was applied. The vibration level was calculated from the ratio of the vibration acceleration detected by the acceleration sensor to the vibration force in the range of 20 Hz to 12,000 Hz. The measurement environment was controlled at 80°C in a thermostatic chamber (PU-3J, manufactured by Espec Corporation). A smaller value indicates a greater reduction in vibration.

[0064] <Fan rotation noise test> The same plate fan molded body as above was used. The fan molded body was attached to the rotating shaft of a motor (AC motor manufactured by Kusatsu Electric Co., Ltd.) and rotated at various rotation speeds. The noise generated during this process was collected using a sound level meter (4189-A-029 manufactured by B&K Co., Ltd.) positioned 100 mm to the side and 200 mm below the fan, and FFT analysis was performed. The measurement time was 60 seconds, the average number of points per frequency was 358, and the frequency weighting characteristic was A-weighting. The measurement environment was controlled at 80°C in a thermostatic chamber (PU-3J manufactured by Espec Co., Ltd.). During the FFT analysis of the fan noise at each rotation speed, the frequency and noise level of the rotation noise peak corresponding to F = 2NZ / 60 were measured. A smaller value indicates a greater reduction in rotation noise.

[0065] [Table 4]

[0066] [Table 5]

[0067] As can be seen from Table 1, the thermoplastic resin composition of Example 3, which contains composite particles with polymer graft chains bonded to the particle surface, had a higher loss factor at both 20°C and 80°C and excellent vibration damping properties compared to the thermoplastic resin composition of Comparative Example 1, in which the same amount of filler and elastomer were added without bonding. This confirmed that vibration and noise could also be further reduced in injection-molded samples, as shown in Tables 4 and 5. Furthermore, as shown in Tables 1 to 3, Examples 1, 2, 4 to 13, 16, and 17, which contain composite particles with polymer graft chains bonded to the particle surface, Example 14, which used a polyamide resin, and Example 15, which used an ABS resin, also showed high loss factors. The loss coefficient was high and the vibration damping was excellent. [Industrial Applicability]

[0068] The thermoplastic resin composition of the present invention can be suitably used in products such as acoustic equipment, electrical appliances, buildings, industrial equipment, automobile parts, motorcycle parts, and containers.

Claims

1. The composite particle includes a thermoplastic resin and a polymer graft chain bonded to the particle surface, and the graft density of the polymer graft chain is 0.001 chain / nm ２ More than 5 chains / nm ２ a thermoplastic resin composition having a thickness of 1 nm or more and 100 nm or less, a polymer graft chain having a thickness of 1 nm or more and 100 nm or less, and a dispersed particle size of composite particles in the thermoplastic resin composition having a thickness of 1 μm or more and 100 μm or less.

2. The thermoplastic resin composition according to claim 1, wherein the amount of the composite particles in the thermoplastic resin composition is 1 part by mass or more and 300 parts by mass or less per 100 parts by mass of the thermoplastic resin.

3. The thermoplastic resin composition according to claim 1 or 2, wherein the blending amount of the thermoplastic resin in the thermoplastic resin composition is 30% by mass or more and 95% by mass or less.

4. The thermoplastic resin composition according to any one of claims 1 to 3, wherein the thermoplastic resin is one or more resins selected from the group consisting of polyolefin resins, polyamide resins, and ABS resins.

5. 5. The thermoplastic resin composition according to claim 1, wherein the particles are metal oxides, metal oxide salts, metal hydroxides, or metal carbonates.

6. The thermoplastic resin composition according to any one of claims 1 to 5, wherein the polymer graft chain is a polymer composed of one or more monomers selected from the group consisting of styrene-based monomers, nitrile-based monomers, (meth)acrylic monomers, unsaturated olefins, and conjugated diene-based monomers.

7. The thermoplastic resin composition according to any one of claims 1 to 6, wherein the polymer graft chains have a glass transition temperature of -30°C or higher and 80°C or lower.

8. The thermoplastic resin composition according to any one of claims 1 to 7, wherein the content of the polymer graft chain of the composite particles in the thermoplastic resin composition is 1 part by mass or more and 100 parts by mass or less per 100 parts by mass of the thermoplastic resin.

9. The thermoplastic resin composition according to any one of claims 1 to 8, wherein the dispersed particle size of the composite particles in the thermoplastic resin composition is 1 µm or more and 50 µm or less.

10. A method for producing a thermoplastic resin composition, comprising: a step of bonding polymer graft chains to particle surfaces; and a step of melt-kneading a thermoplastic resin with composite particles having polymer graft chains bonded to the particle surfaces, wherein the film thickness of the polymer graft chains in the composite particles is 1 nm or more and 100 nm or less; and the method comprises the following steps 1 and 2, wherein the dispersed particle size of the composite particles in the thermoplastic resin composition is 1 μm or more and 100 μm or less. Step 1: A step of bonding a polymerization initiating group to the particle surface Step 2: A step of contacting particles having polymerization initiation groups on the surface with a monomer under living radical polymerization conditions

11. The method for producing the thermoplastic resin composition according to claim 10, further comprising a molding process.

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