WO2023238797A1

WO2023238797A1 - Composition

Info

Publication number: WO2023238797A1
Application number: PCT/JP2023/020651
Authority: WO
Inventors: 雄一 ▲桑▼原; 敦美光永; 博道加茂
Original assignee: Ａｇｃ株式会社
Priority date: 2022-06-08
Filing date: 2023-06-02
Publication date: 2023-12-14

Abstract

Provided is a composition that includes a fluoroelastomer or a hot-melt tetrafluoroethylene polymer, the composition being suitable for use as a thermal interface material and making it possible to form molded articles, such as sheets, that have excellent mechanical properties and heat resistance, have a low linear expansion coefficient, dielectric constant, and dielectric tangent, and, in particular, have excellent thermal conductivity while still being electrically insulating. A composition according to the present invention includes a fluoroelastomer or a hot-melt tetrafluoroethylene polymer that has a melting temperature of above 100°C but not above 325°C, a thermally conductive inorganic filler that has an average particle diameter of at least 10 μm, and a thermally conductive filler that has an average particle diameter of less than 2 μm.

Description

Composition

The present invention relates to a composition containing a fluoroelastomer or a tetrafluoroethylene polymer and a plurality of predetermined thermally conductive fillers.

Generated from electronic components such as computer chips (CPUs), video graphics arrays, servers, game consoles, smartphones, and LED boards, as well as semiconductor modules including power semiconductors used in inverters and converters for electric vehicles and power transmission systems. In order to dissipate a large amount of heat, a thermal interface material (hereinafter also referred to as "TIM") is used as a heat dissipation material. The TIM typically has the role of transferring excess heat from the electronic components to a heat spreader and then transferring the heat to a heat sink.
Traditionally, phase change materials such as paraffin wax, grease-like materials, and elastomeric tapes are used as TIMs because they can be spread in very thin layers and provide intimate contact between adjacent surfaces; However, there are problems in that the performance is likely to deteriorate.
Compositions of fluoroethylene-based polymers and other components have been proposed to obtain heat dissipating materials applicable to TIMs. Patent Document 1 proposes a heat dissipating material in which a fluoroelastomer of a predetermined viscosity is blended with an insulating thermally conductive filler. Patent Document 2 proposes a heat dissipation material in which boron nitride filler with a predetermined particle size is blended with a heat-melting tetrafluoroethylene polymer.

Japanese Patent Application Publication No. 2019-085559 International Publication No. 2020/045260

Fluoroethylene-based polymers have low surface tension and low affinity with other components. Therefore, in a molded article formed from a composition containing a fluoroethylene-based polymer and a thermally conductive inorganic filler, interaction between the components is insufficient, making it difficult to fully exhibit the physical properties of each component. The present inventors have discovered that even with the compositions described in prior art documents, there is still room for improvement in order to achieve the electrical insulation, heat resistance, thermal conductivity, and mechanical properties required for TIM. I have knowledge.

The present inventors have discovered that a composition containing a fluoroelastomer or a tetrafluoroethylene polymer, a predetermined thermally conductive inorganic filler, and a predetermined thermally conductive filler has excellent dispersibility, and that molded products thereof have excellent mechanical properties, The inventors have discovered that they have excellent heat resistance, low coefficient of linear expansion, low dielectric constant, and low dielectric loss tangent, and are particularly excellent in thermal conductivity while maintaining electrical insulation properties, leading to the present invention.
It is an object of the present invention to provide such a composition and a thermal interface material containing the composition.

The present invention has the following aspects.
[1] A fluoroelastomer or a heat-melting tetrafluoroethylene polymer with a melting temperature of more than 100°C and 325°C or less,
A thermally conductive inorganic filler having an average particle size of 10 μm or more,
A composition comprising: a thermally conductive filler having an average particle diameter of less than 2 μm.
[2] The composition of [1], comprising the fluoroelastomer, the thermally conductive inorganic filler having an average particle size of 10 μm or more, and the thermally conductive filler having an average particle size of less than 2 μm.
[3] The total amount of the thermally conductive inorganic filler and the thermally conductive filler in the total amount of the fluoroelastomer, the thermally conductive inorganic filler, and the thermally conductive filler is more than 50% by volume, [2] Composition.
[4] The composition according to [2] or [3], wherein the amount of the thermally conductive inorganic filler in the total amount of the thermally conductive inorganic filler and the thermally conductive filler is more than 30% by volume.
[5] The composition according to any one of [2] to [4], wherein the thermally conductive filler has an average particle diameter of more than 0.05 μm and less than 1 μm.
[6] The composition according to any one of [2] to [5], wherein the thermally conductive inorganic filler is boron nitride, aluminum nitride, silicon nitride, or aluminum oxide.
[7] Any of [2] to [6], wherein the thermally conductive filler is aluminum oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, carbon fiber, graphite, graphene, carbon nanotube, silver or copper. composition.
[8] A sheet containing a fluoroelastomer, a thermally conductive inorganic filler having an average particle size of 10 μm or more, and a thermally conductive filler having an average particle size of less than 2 μm.
[9] The heat-melting tetrafluoroethylene polymer having a melting temperature of more than 100°C and 325°C or less, the thermally conductive inorganic filler having an average particle size of 10 μm or more, and the heat-melting inorganic filler having an average particle size of less than 2 μm. The composition of [1], comprising a conductive filler.
[10] The total amount of the thermally conductive inorganic filler and the thermally conductive filler in the total amount of the thermally meltable tetrafluoroethylene polymer, the thermally conductive inorganic filler, and the thermally conductive filler is more than 50% by volume. The composition of [9].
[11] The composition according to [9] or [10], wherein the amount of the thermally conductive inorganic filler in the total amount of the thermally conductive inorganic filler and the thermally conductive filler is more than 30% by volume.
[12] The composition according to any one of [9] to [11], wherein the thermally conductive filler has an average particle diameter of more than 0.05 μm and less than 1 μm.
[13] The composition according to any one of [9] to [12], wherein the thermally conductive inorganic filler is boron nitride, aluminum nitride, silicon nitride, or aluminum oxide.
[14] Any of [9] to [13], wherein the thermally conductive filler is aluminum oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, carbon fiber, graphite, graphene, carbon nanotube, silver or copper. composition.
[15] A heat-melting tetrafluoroethylene polymer with a melting temperature of more than 100°C and 325°C or less, a thermally conductive inorganic filler with an average particle size of 10 μm or more, and a thermally conductive filler with an average particle size of less than 2 μm. and sheets, including.

According to the present invention, a composition containing a fluoroelastomer or a tetrafluoroethylene polymer, a predetermined thermally conductive inorganic filler, and a predetermined thermally conductive filler and having excellent dispersibility is provided. From such a composition, it is possible to form a molded article such as a sheet that has excellent mechanical properties and heat resistance, has a low linear expansion coefficient, dielectric constant, and dielectric loss tangent, and has excellent thermal conductivity while maintaining electrical insulation properties. It can be suitably used as a thermal interface material.

The following terms have the following meanings:
"Volume" is a value calculated by dividing the mass of an object by its specific gravity.
"Average particle diameter (D50)" is the volume-based cumulative 50% diameter of particles determined by laser diffraction/scattering method. That is, the particle size distribution is measured by a laser diffraction/scattering method, a cumulative curve is determined with the total volume of the particle population as 100%, and the particle diameter is the point on the cumulative curve where the cumulative volume becomes 50%.
The D50 of the particles is determined by dispersing the particles in water and analyzing the particles using a laser diffraction/scattering method using a laser diffraction/scattering particle size distribution analyzer (LA-920 analyzer manufactured by Horiba, Ltd.).
"Melting temperature" is the temperature corresponding to the maximum value of the melting peak of the polymer as measured by differential scanning calorimetry (DSC).
"Glass transition point (Tg)" is a value measured by analyzing a polymer using a dynamic mechanical analysis (DMA) method.
A "unit" in a polymer means an atomic group based on the monomer formed by polymerization of the monomer. The unit may be a unit directly formed by a polymerization reaction, or may be a unit in which a part of said unit is converted into another structure by processing the polymer. Hereinafter, a unit based on monomer a will also be simply referred to as a "monomer a unit."

The composition according to the first embodiment of the present invention (hereinafter also referred to as "the present composition") comprises a fluoroelastomer and a thermally conductive inorganic filler (hereinafter referred to as "first filler") having an average particle size of 10 μm or more. ) and a thermally conductive filler (hereinafter also referred to as "second filler") having an average particle diameter of less than 2 μm.

This composition has excellent dispersibility, has high physical properties of the fluoroelastomer, the first filler, and the second filler, has excellent mechanical properties, heat resistance, and has low linear expansion coefficient, dielectric constant, and dielectric loss tangent. It is easy to form molded products such as sheets that have low thermal conductivity while maintaining electrical insulation. Although the reason is not necessarily clear, it is thought to be as follows.

Fluoroelastomers have low compatibility with other materials. Therefore, particularly in the case of a particulate filler such as the above-mentioned second filler, the second fillers tend to aggregate with each other in the composition, and not only is it difficult to exhibit its physical properties, but also the mechanical properties of the molded product obtained therefrom are etc. are also likely to decrease.
Therefore, in this composition, a first filler having a sufficiently large average particle diameter (D50) is used in combination with the second filler to promote interaction between the two fillers. In other words, it can be considered that aggregation of the second filler is suppressed by using the first filler as a base particle and having the second filler on the surface or in the vicinity thereof. When the fillers in the composition are in such a state, their surface area increases relatively, promoting interaction between each filler and the fluoroelastomer, and improving the uniform dispersibility of the composition. it is conceivable that. In a molded article such as a sheet formed from such a composition, the second filler is efficiently and densely filled into the gap packed by the first filler, and a highly advanced filler path is likely to be formed, which leads to molding. It is thought that this improves thermal conductivity while maintaining the heat resistance, coefficient of linear expansion, and electrical properties of the material, especially electrical insulation. Furthermore, it is thought that the contact interface between the fluoroelastomer and the first filler and the second filler became larger, and the mechanical properties such as the bending strength of the molded product were also improved.

Such a tendency is achieved when the total amount of the first filler and the second filler is preferably more than 50% by volume in the total amount of the fluoroelastomer, the first filler, and the second filler, and the total amount of the first filler and the second filler is preferably more than 50% by volume. This becomes even more noticeable when the amount of 1 filler is preferably more than 30% by volume.

Fluoroelastomers are polymers containing units based on fluoroolefins, such as tetrafluoroethylene (TFE), hexafluoropropylene (HFP), vinylidene fluoride (VdF), vinyl fluoride (VF) and chlorotrifluoroethylene (CTFE). Polymers containing units based on at least one fluoroolefin selected from the group consisting of are preferred. Further, the fluoroelastomer is an elastic polymer having no melting point and exhibiting a storage modulus of 80 or more at 100° C. and 50 cpm as measured according to ASTM D6204.
One type of fluoroelastomer may be used, or two or more types may be used in combination.

The fluoroelastomer may be a fluoroelastomer consisting only of one or more units selected from the group consisting of TFE units, HFP units, VdF units, VF units, and CTFE units, and the above units and monomers other than the above units It may also be a fluoroelastomer containing a base unit.

Specific examples of monomers other than the above units include ethylene (E), propylene (P), and perfluoro(alkyl vinyl ether) (PAVE).
Specific examples of PAVE include perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), and perfluoro(butyl vinyl ether).

Examples of fluoroelastomers include TFE/P-containing polymers (meaning polymers containing TFE units and P units. The same applies to the following description), HFP/VdF-containing polymers, and TFE/PAVE-containing polymers. . In addition, the sum of each unit connected by "/", for example, in the case of a TFE/P-containing polymer, the ratio of the sum of TFE units and P units is preferably 50 mol% or more of all units constituting the polymer. . The same applies to other "containing polymers".
Note that the TFE/PAVE-containing polymer does not include a polymer that further contains a P unit or a VdF unit, even if it has a TFE unit and a PAVE unit. Further, the HFP/VdF-containing polymer does not include a polymer that further contains a P unit, even if it has an HFP unit and a VdF unit.

Examples of TFE/P-containing polymers include TFE/P (meaning a polymer consisting of TFE units and P units. The same applies to others), TFE/P/VF, TFE/P/VdF, TFE/P/ E, TFE/P/TFP, TFE/P/PAVE, TFE/P/1,3,3,3-tetrafluoropropene, TFE/P/2,3,3,3-tetrafluoropropene, TFE/P/ Examples include TrFE, TFE/P/DiFE, TFE/P/VdF/TFP, and TFE/P/VdF/PAVE.
HFP/VdF-containing polymers include HFP/VdF, TFE/VdF/HFP, TFE/VdF/HFP/TFP, TFE/VdF/HFP/PAVE, VdF/HFP/TFP, and VdF/HFP/PAVE.
TFE/PAVE-containing polymers include TFE/PAVE, TFE/PMVE, and TFE/PMVE/PPVE.

The Mooney viscosity (ML ₁₊₁₀ , 121° C.) of the fluoroelastomer is preferably from 20 to 200, more preferably from 30 to 150, even more preferably from 40 to 120. Mooney viscosity is a measure of molecular weight and is measured according to JIS K6300-1:2000. A large value indicates a high molecular weight, and a small value indicates a low molecular weight. If the Mooney viscosity is within the above range, molded articles such as sheets formed from the composition will have excellent mechanical properties.

The thermal conductivity of each of the first filler and the second filler contained in the present composition alone is preferably 20 W/m·K or more, and more preferably 30 W/m·K or more. The upper limit of the thermal conductivity of each of the first filler and the second filler alone is not particularly limited and is preferably higher, but generally it is preferably 3000 W/m・K or less, and 2500 W/m・K or less. K or less is more preferable.

The shape of the first filler may be spherical, needle-like (fibrous), or plate-like. It may be equiaxed, leaf-like, mica-like, block-like, flat-plate-like, wedge-like, rosette-like, mesh-like, or prismatic.
Among these, the shape of the first filler is preferably non-spherical, and more preferably scale-like or columnar. In this case, it is considered that in the present composition and the molded product such as a sheet formed from the present composition, the first filler tends to take a card house structure and easily forms a heat conduction path. As a result, the present composition has excellent dispersibility, and the molded product tends to have excellent thermal conductivity (thermal conductivity) and low linear expansion.
The aspect ratio of the first filler is preferably more than 1, more preferably 2 or more, and even more preferably 5 or more. The aspect ratio is preferably 10,000 or less.

Examples of the first filler include silicon compounds such as quartz powder, silica, wollastonite, talc, silicon nitride, silicon carbide, and mica; nitrogen compounds such as boron nitride and aluminum nitride; aluminum oxide, zinc oxide, titanium oxide, and titanium oxide. Examples include metal oxides such as cerium, beryllium oxide, magnesium oxide, nickel oxide, vanadium oxide, copper oxide, iron oxide, and silver oxide. The first filler may be used alone or in combination of two or more.
Among these, it is preferable that the first filler is boron nitride, aluminum nitride, silicon nitride, or aluminum oxide, and boron nitride is more preferable.

Specific examples of boron nitride fillers include the "HP-40MF" series, the "HP-40J" series (all manufactured by JFE Minerals), the "UHP" series (manufactured by Showa Denko), and the "Denka Boron Nitride" series. Examples include "GP" and "HGP" grades (manufactured by Denka Corporation).
Specific examples of aluminum nitride fillers include the "High Purity Aluminum Nitride" series (manufactured by Tokuyama Co., Ltd.) and the "Toyal Tech Filler TFZ" series (manufactured by Toyo Aluminum Co., Ltd.).
Specific examples of silicon nitride fillers include the "Denka Silicon Nitride" series (manufactured by Denka Corporation) and the "UBE Silicon Nitride" series (manufactured by UBE Corporation).
Specific examples of aluminum oxide fillers include the "Alumina Beads CB" series (Showa Denko Co., Ltd.) and the "Taimicron" series (Daimei Kagaku Kogyo Co., Ltd.).

D50 of the first filler is 10 μm or more, preferably 20 μm or more, and more preferably 30 μm or more. D50 of the first filler is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 60 μm or less.
The true density of the first filler is preferably 0.2 to 1 g/cm ³ .
The bulk density of the first filler is preferably 0.1 to 0.5 g/cm ³ .
The compressive strength of the first filler is preferably 30 to 200 MPa. Note that the compressive strength is the compressive strength measured in accordance with ASTM D 3102-78.

The surface of the first filler may be surface-treated with a silane coupling agent. Examples of the silane coupling agent include vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-isocyanatepropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, p-styryltrimethoxysilane, 3-trimethoxysilylpropylsuccinic anhydride, N-2-(amino methyl)-8-aminooctyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxy cyclohexyl)ethyltrimethoxysilane.

The shape of the second filler may be spherical, acicular (fibrous), or plate-like, but the heat conductivity of molded products such as sheets obtained from the present composition and TIM containing the present composition is From the viewpoint of further improving properties, a spherical shape is preferable.
The spherical second filler may have an elliptical shape, but is preferably substantially spherical. Here, "substantially spherical" means that when the filler is observed using a scanning electron microscope (SEM), the proportion of particles with a ratio of the short axis to the long axis of 0.7 or more is 95% or more. .
In this case, the present composition tends to have excellent dispersibility and processability. In addition, in a molded product such as a sheet formed from the present composition, the second filler is efficiently arranged and densely packed in the gap packed by the first filler, making it easy to form a heat conduction path and machine It is easy to obtain molded products such as sheets that have excellent physical properties, low coefficient of linear expansion, low dielectric constant, and low dielectric loss tangent, and have excellent thermal conductivity while maintaining electrical insulation.

The second filler is more densely packed into the gap where the first filler is packed in a molded product such as a sheet, forming a filler path, and highly exhibits the physical properties of the second filler itself, thereby forming a molded product. From the viewpoint of improving the thermal conductivity of the product, it is preferable that the filler is not surface-treated. Note that "surface treatment" includes surface treatment using an organic surface treatment agent such as a silane coupling agent, an inorganic surface treatment agent such as an inorganic acid, or a physical manipulation.

Examples of the second filler include metal oxides such as aluminum oxide, zinc oxide, titanium oxide, cerium oxide, beryllium oxide, magnesium oxide, nickel oxide, vanadium oxide, copper oxide, iron oxide, and silver oxide; boron nitride, aluminum nitride Nitrogen compounds such as quartz powder, silica, wollastonite, talc, silicon nitride, silicon carbide, mica, etc.; carbon fibers; carbon allotropes such as graphite, graphene, carbon nanotubes; metals such as silver, copper; Can be mentioned. One type of second filler may be used, or two or more types may be used in combination.
Among these, the second filler is preferably aluminum oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, carbon fiber, graphite, graphene, carbon nanotube, silver, or copper.
In this case, it is easy to obtain a molded article with excellent electrical properties, low linear expansion, and thermal conductivity from the present composition.

The D50 of the second filler is preferably more than 0.05 μm and less than 1 μm.
The D50 of the second filler is more preferably 0.08 μm or more, and even more preferably 0.1 μm or more. The D50 of the second filler is more preferably 0.8 μm or less, and even more preferably 0.5 μm or less.
The true density of the second filler is preferably 0.2 to 1 g/cm ³ .
The bulk density of the second filler is preferably 0.1 to 0.5 g/cm ³ .
The compressive strength of the second filler is preferably 30 to 200 MPa. Note that the compressive strength is the compressive strength measured in accordance with ASTM D 3102-78.

Specifically, "UCP-030N" (Sumitomo Manufactured by Kinzoku Mining Co., Ltd., copper powder, D50: 0.27 μm, oval shape), “TM-5D” (manufactured by Daimei Chemical Co., Ltd., D50: 0.2 μm, oval shape), “FS-1” (manufactured by JFE Mineral Co., Ltd.) , boron nitride powder, D50: 0.2 μm, plate shape), etc.

In the present composition, it is preferable that the first filler has a non-spherical shape (scaly, columnar), and the second filler has a spherical shape. Further, the first filler and the second filler may be the same type of filler with different D50s, but the first filler and the second filler may be of different types.
In this composition, the ratio of the D50 of the first filler to the D50 of the second filler is preferably 30 or more, more preferably 50 or more. The above ratio is preferably 500 or less, more preferably 250 or less.

In the present composition, the total amount of the first filler and the second filler in the total amount of the fluoroelastomer, the first filler, and the second filler is preferably more than 50 volume %, more preferably 55 volume % or more. , more preferably 60% by volume or more. . The total amount of the first filler and the second filler in the total amount of the fluoroelastomer, the first filler, and the second filler is preferably 75% by volume or less. Due to the above-mentioned mechanism of action, even when the total amount of filler is within this range, the present composition has excellent dispersibility and can impart the respective filler physical properties to a high degree to the molded product.

Further, in the present composition, the amount of the first filler in the total amount of the first filler and the second filler is preferably more than 30 volume%, more preferably more than 50 volume%, and more than 60 volume%. It is more preferable that The amount of the first filler in the total amount of the first filler and the second filler is preferably 95% by volume or less, more preferably 90% by volume or less.
In this case, in the above-described working mechanism, it is likely that the second filler can be densely filled into the gap between the packings of the first filler. Furthermore, the interaction between different types of fillers is enhanced, and aggregation of the first filler and the second filler is easily suppressed, and the dispersibility of the present composition is likely to be improved.

In the total volume of the fluoroelastomer, the first filler, and the second filler in the present composition, the volume concentration of the fluoroelastomer, the volume concentration of the first filler, and the volume concentration of the second filler are, in this order, 10 to 60%, 30% 80%, preferably 10% to 30%.
When the volume concentration is within this range, the composition tends to have excellent dispersibility. Further, from this composition, it is easy to obtain molded products such as sheets that have a low coefficient of linear expansion, a low dielectric constant, and a low dielectric loss tangent, and have excellent thermal conductivity while maintaining electrical insulation.

The present composition may further contain other resins other than the fluoroelastomer as long as the effects of the present invention are not impaired. Such other resins may be contained in the present composition as non-hollow particles, or when the present composition includes a liquid dispersion medium described below, they may be contained dissolved or dispersed in the liquid dispersion medium. good.
Other resins include fluororesins other than fluoroelastomers, polyester resins such as liquid crystalline aromatic polyesters, polyimide resins, polyamideimide resins, epoxy resins, maleimide resins, urethane resins, polyphenylene ether resins, polyphenylene oxide resins, and polyphenylene sulfide. Examples include resin.
The other resin is preferably an aromatic polymer, and more preferably at least one aromatic imide polymer selected from the group consisting of aromatic polyimide, aromatic polyamic acid, aromatic polyamideimide, and a precursor of aromatic polyamideimide. . Preferably, the aromatic polymer is included in the composition as a varnish dissolved in a liquid dispersion medium.

Specific examples of aromatic imide polymers include the "Yupia-AT" series (manufactured by UBE), the "Neoprim (registered trademark)" series (manufactured by Mitsubishi Gas Chemical Co., Ltd.), and the "Spixeria (registered trademark)" series (manufactured by Somar). ), “Q-PILON (registered trademark)” series (manufactured by P.I. Technology Institute), “WINGO” series (manufactured by Wingo Technology), “TOMIDE (registered trademark)” series (manufactured by T&K TOKA), “KPI-” MX” series (manufactured by Kawamura Sangyo Co., Ltd.), “HPC-1000” and “HPC-2100D” (all manufactured by Showa Denko Materials Co., Ltd.).

When the present composition further contains other resins, the volume concentration of the other resins relative to the total volume of the fluoroelastomer, the first filler, and the second filler is preferably 0.1% by volume or more, more preferably 1% by volume or more. preferable. The volume concentration is preferably 15% by volume or less, more preferably 10% by volume or less.

The present composition may be in powder form, or may be in liquid form containing a liquid dispersion medium.
The liquid dispersion medium is preferably a compound that is liquid at 25°C under atmospheric pressure and has a boiling point of 50 to 240°C. One type of liquid dispersion medium may be used, or two or more types may be used. When two types of liquid dispersion media are used, it is preferable that the two types of liquid dispersion media are compatible with each other.

The liquid dispersion medium is preferably a compound selected from the group consisting of water, hydrocarbons, amides, ketones, and esters.
Examples of hydrocarbons include alicyclic skeleton hydrocarbons such as hexane, heptane, octane, decane, and methylcyclohexane, and aromatic hydrocarbons such as toluene, ethylbenzene, and xylene.
Amides include N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropanamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy- Examples include N,N-dimethylpropanamide, N,N-diethylformamide, hexamethylphosphoric triamide, and 1,3-dimethyl-2-imidazolidinone.
Examples of ketones include acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl n-pentyl ketone, methyl isopentyl ketone, 2-heptanone, cyclopentanone, cyclohexanone, and cycloheptanone.
Examples of esters include methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethyl 3-ethoxypropionate, γ-butyrolactone, γ- One example is valerolactone.

When the present composition contains a liquid dispersion medium, the content of the liquid dispersion medium is preferably 10% by volume or more, more preferably 20% by volume or more. The content of the liquid dispersion medium is preferably 60% by volume or less, more preferably 50% by volume or less.
When the present composition contains a liquid dispersion medium, the solid content concentration in the present composition is preferably 50% by volume or more. The solid content concentration is preferably 90% by volume or less. In addition, solid content means the total amount (total mass or total volume) of substances forming solid content in a molded article formed from the present composition. Specifically, the fluoroelastomer, the first filler, and the second filler are solids, and if the composition includes other resins, the other resins are also solids, and the total volume concentration of these components is the solid content concentration in this composition.

The present composition, particularly the present composition containing a liquid dispersion medium, preferably further contains a nonionic surfactant from the viewpoint of improving the dispersion stability of the fluoroelastomer, the first filler, and the second filler.
Examples of nonionic surfactants include glycol surfactants, acetylene surfactants, silicone surfactants, and fluorine surfactants.
Specific examples of nonionic surfactants include the "Ftergent" series (manufactured by Neos), the "Surflon" series (manufactured by AGC Seimi Chemical), the "Megafac" series (manufactured by DIC), and the "Unidyne" series (manufactured by DIC). BYK-347, BYK-349, BYK-378, BYK-3450, BYK-3451, BYK-3455, BYK-3456 (BYK-3456) Japan Co., Ltd.), "KF-6011", "KF-6043" (manufactured by Shin-Etsu Chemical Co., Ltd.), "Tergitol" series (manufactured by Dow Chemical Co., Ltd., "Tergitol TMN-100X", etc.).
When the composition contains a nonionic surfactant, the content of the nonionic surfactant in the composition is preferably 1 to 15% by volume.

The composition further includes a thixotropic agent, a viscosity modifier, an antifoaming agent, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a whitening agent, a coloring agent, It may contain additives such as a conductive agent, a mold release agent, and a flame retardant.

When the present composition contains a liquid dispersion medium and is in a liquid state, its viscosity is preferably 10 mPa·s or more, more preferably 100 mPa·s or more. The viscosity of the present composition is preferably 10,000 mPa·s or less, more preferably 3,000 mPa·s or less.
When the present composition is liquid and contains a liquid dispersion medium, the thixotropic ratio thereof is preferably 1.0 to 3.0.

The present composition is obtained by mixing the fluoroelastomer, the first filler, the second filler, and other resins, liquid dispersion medium, surfactant, additives, etc. as necessary.
The present composition may be obtained by mixing the fluoroelastomer, the first filler, and the second filler all at once, or may be obtained by mixing them separately in sequence, or by preparing a masterbatch of these in advance and mixing it with the remaining components. may be mixed. There is no particular restriction on the order of mixing, and the mixing method may be all at once or divided into multiple batches.
Mixing devices for obtaining the present composition include stirring devices equipped with blades such as Henschel mixer, pressure kneader, Banbury mixer, and planetary mixer, ball mill, attritor, basket mill, sand mill, sand grinder, dyno mill, Grinding equipment equipped with media such as Dispermat, SC mill, spike mill, and agitator mill, microfluidizer, nanomizer, ultimizer, ultrasonic homogenizer, resolver, disperser, high-speed impeller, thin-film rotating high-speed mixer, rotation-revolution stirrer and a dispersion device equipped with other mechanisms such as a V-type mixer.

The method for producing the present composition containing a liquid dispersion medium includes first adding a first filler to a liquid dispersion medium containing a fluoroelastomer, then adding a second filler and mixing the fluoroelastomer, first filler, and This is preferable from the viewpoint of improving the dispersibility of the second filler.
More specifically, the fluoroelastomer is dissolved in a portion of the liquid dispersion medium in advance, then the first filler and the second filler are sequentially added and kneaded, and the resulting kneaded product is added to the remaining liquid dispersion medium. Examples include manufacturing methods for obtaining the present composition. The liquid dispersion medium used during kneading and addition may be the same type of liquid dispersion medium or may be different types of liquid dispersion medium. Other resins, surfactants, and additives may be mixed during kneading or may be mixed during addition.

The kneaded product obtained by kneading may be in the form of a paste (such as a paste with a viscosity of 1000 to 100000 mPa·s), or in the form of a wet powder (a wet powder with a viscosity of 10000 to 100000 Pa·s as measured by a capillograph). etc.) may be used.
In addition, the viscosity measured by capillograph means that a capillary with a capillary length of 10 mm and a capillary radius of 1 mm is used, the furnace body diameter is 9.55 mm, the load cell capacity is 2 t, the temperature is 25°C, and the shear rate is 1 s ^. This value is measured as ¹ .

Mixing during kneading is preferably performed using a planetary mixer. A planetary mixer is a stirring device having two shaft stirring blades that rotate and revolve around each other.
Mixing during addition is preferably carried out using a thin film swirling type high speed mixer. A thin film swirling type high speed mixer spreads a kneaded material containing a fluoroelastomer, a first filler and a second filler, and a liquid dispersion medium into a thin film on the inner wall surface of a cylindrical stirring tank, and swirls the mixture to generate centrifugal force. This is a stirring device that mixes while applying

From this composition, it is easy to obtain molded products having a thermal conductivity of 2.0 W/m·K or more. The thermal conductivity of such a molded article is preferably 2.0 to 100 W/m·K.
The dielectric constant of a molded product obtained from the present composition is preferably 2.4 or less, more preferably 2.0 or less. Moreover, it is preferable that the dielectric constant is more than 1.0. The dielectric loss tangent of the molded product is preferably 0.0022 or less, more preferably 0.0020 or less. Moreover, it is preferable that the dielectric loss tangent is more than 0.0010.

If this composition is subjected to a molding method such as extrusion, a molded product such as a sheet containing a fluoroelastomer, a first filler, and a second filler can be obtained.
When the present composition contains a liquid dispersion medium and is in a liquid state, it is preferable to extrude the present composition into a sheet form. The sheet obtained by extrusion may be further subjected to press molding, calendar molding, etc. and then cast. Preferably, the sheet is further heated to remove the liquid dispersion medium.
When the composition is in powder form, it is preferred to melt extrude the composition. Extrusion molding can be performed using a single screw extruder, a multi-screw extruder, or the like.
Alternatively, the composition may be injection molded to obtain a molded product.
When forming a molded product, the present composition may be directly melt-extruded or injection molded, or the composition is melt-kneaded to form pellets, and the pellets are melt-extruded or injection molded to form a molded product such as a sheet. You may obtain .

The thickness of the sheet obtained from the present composition is preferably 50 μm or more, more preferably 75 μm or more, and even more preferably 100 μm or more. The thickness of the sheet is preferably 1000 μm or less.
The preferable ranges of the thermal conductivity, dielectric constant, and dielectric loss tangent of the sheet are the same as the ranges of the thermal conductivity, dielectric constant, and dielectric loss tangent of the molded article, respectively. Note that the thermal conductivity of the sheet means the thermal conductivity in the in-plane direction of the sheet.
The coefficient of linear expansion of the sheet is preferably 100 ppm/°C or less, more preferably 80 ppm/°C or less. The lower limit of the linear expansion coefficient of the sheet is 30 ppm/°C. Note that the linear expansion coefficient means a value obtained by measuring the linear expansion coefficient of a test piece in the range of 25° C. or higher and 260° C. or lower according to the measurement method specified in JIS C 6471:1995.

A laminate can be formed by laminating such sheets on a base material. The method for producing the laminate includes a method of extruding the present composition together with a raw material for the base material using a coextruder as the extruder, a method of extruding the present composition on the base material, and a method of extruding the present composition on the base material. Examples include a method of thermocompression bonding with materials.
As a base material, metal substrates such as metal foils such as copper, nickel, aluminum, titanium, and alloys thereof; polyester, polyimide, polyamide, polyetheramide, polyphenylene sulfide, polyallyletherketone, polyamideimide, liquid crystalline polyester, Suitable examples include films of heat-resistant resins such as tetrafluoroethylene polymers; prepreg substrates (precursors of fiber-reinforced resin substrates); ceramic substrates such as silicon carbide, aluminum nitride, and silicon nitride; and glass substrates.

Examples of the shape of the base material include a planar shape, a curved shape, and an uneven shape. Further, the shape of the base material may be any of foil, plate, film, and fiber.
The ten-point average roughness of the surface of the base material is preferably 0.01 to 0.05 μm.
The peel strength between the sheet and the base material is preferably 10 N/cm or more, more preferably 15 N/cm or more. The peel strength is preferably 100 N/cm or less.

By disposing the present composition on the surface of a base material and forming a polymer layer containing a fluoroelastomer, a first filler, and a second filler, a laminate having a base material layer and a polymer layer composed of the base material can be obtained. is obtained. The polymer layer is preferably formed by disposing the present composition containing a liquid dispersion medium on the surface of a substrate and heating to remove the dispersion medium. By separating the base material from such a laminate, a sheet containing a fluoroelastomer, a first filler, and a second filler can be obtained.
Examples of the base material include those similar to those that can be laminated with the sheet described above, and preferred embodiments thereof are also the same.

Methods for disposing the composition include a coating method, a droplet discharge method, and a dipping method, with roll coating, knife coating, bar coating, die coating, and spraying being preferred.
Heating during removal of the liquid dispersion medium is preferably carried out at 100 to 200° C. for 0.1 to 30 minutes. During this heating, a polymer layer is formed by packing the fluoroelastomer, the first filler, and the second filler. During heating, air may be blown to encourage removal of the liquid dispersion medium by air drying.
Examples of the heating device include an oven and a ventilation drying oven. The heat source in the device may be a contact heat source (hot air, hot plate, etc.) or a non-contact heat source (infrared rays, etc.).
Heating may be performed under normal pressure or under reduced pressure.
The atmosphere for heating may be either an air atmosphere or an inert gas (helium gas, neon gas, argon gas, nitrogen gas, etc.) atmosphere.

The polymer layer is formed through the steps of placing and heating the composition. These steps may be performed once or may be repeated two or more times. For example, the composition may be placed on the surface of a base material and heated to form a polymer layer, and then the composition may be placed on the surface of the polymer layer and heated to form a second polymer layer. . Further, at the stage where the present composition is placed on the surface of the substrate and heated to remove the liquid dispersion medium, the present composition may be further placed on the surface and heated to form a polymer layer.

This composition is useful as a material for imparting insulation, heat resistance, corrosion resistance, chemical resistance, water resistance, impact resistance, and thermal conductivity.
Specifically, the present composition is used in printed wiring boards, thermal interface materials, power module substrates, coils used in power devices such as motors, in-vehicle engines, heat exchangers, vials, syringes, Ampules, medical wires, secondary batteries such as lithium ion batteries, primary batteries such as lithium batteries, radical batteries, solar cells, fuel cells, lithium ion capacitors, hybrid capacitors, capacitors, capacitors (aluminum electrolytic capacitors, tantalum electrolytic capacitors, etc.) ), electrochromic devices, electrochemical switching devices, electrode binders, electrode separators, and electrodes (positive and negative electrodes).
The composition is also useful as an adhesive for bonding parts together. Specifically, this composition can be used for adhesion of ceramic parts, adhesion of metal parts, adhesion of electronic parts such as IC chips, resistors, and capacitors on substrates of semiconductor elements and module parts, adhesion of circuit boards and heat sinks, and adhesion of LEDs. Can be used to bond chips to substrates.

The present invention is also a thermal interface material (TIM) containing the present composition. The TIM containing this composition has the physical properties of the fluoroelastomer, the first filler, and the second filler to a high degree, has excellent mechanical properties and heat resistance, and has a low linear expansion coefficient, dielectric constant, and dielectric loss tangent. Excellent thermal conductivity.
This composition is suitable for electronic components such as computer chips (CPUs), video graphics arrays, servers, game consoles, smartphones, and LED boards, as well as semiconductors including power semiconductors used in electric vehicles, inverters and converters of power transmission systems, etc. It can be particularly suitably used in TIM applications for dissipating large amounts of heat generated from modules and the like.

The present invention is also a sheet containing a fluoroelastomer, a first filler, and a second filler. Details of the fluoroelastomer, the first filler, the second filler, and other optional components in such a sheet are the same as those described above in the description of the present composition.
Such sheets are preferably formed from the composition in the manner described above. The preferable ranges of the sheet thickness, thermal conductivity, dielectric constant, dielectric loss tangent, and coefficient of linear expansion are the same as described above. Such a sheet can be suitably used as a TIM.

Molded products such as sheets and laminates formed from the present composition are useful as antenna parts, printed circuit boards, aircraft parts, automobile parts, sports equipment, food industry products, heat dissipation parts, and the like.
Specifically, electric wire coating materials (aircraft wires, etc.), enameled wire coating materials used in motors of electric vehicles, electrical insulation tape, oil drilling insulation tape, oil transportation hoses, hydrogen tanks, printed circuit boards, etc. materials, separation membranes (precision filtration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, gas separation membranes, etc.), electrode binders (for lithium secondary batteries, fuel cells, etc.), copy rolls, Covers for furniture, automobile dashboards, home appliances, etc., sliding parts (load bearings, yaw bearings, sliding shafts, valves, bearings, bushes, seals, thrust washers, wear rings, pistons, slide switches, gears, cams, belt conveyors) , food conveyance belts, etc.), tension ropes, wear pads, wear strips, tube lamps, test sockets, wafer guides, centrifugal pump wear parts, chemical and water supply pumps, tools (shovels, files, chisels, saws, etc.), Boilers, hoppers, pipes, ovens, baking molds, chutes, racket guts, dies, toilet bowls, container coverings, mounted heat dissipation boards for power devices, heat dissipation components for wireless communication devices, transistors, thyristors, rectifiers, transformers, power MOS FETs , CPUs, heat dissipation fins, metal heat dissipation plates, blades for wind turbines, wind power generation equipment, aircraft, etc., casings for personal computers and displays, electronic device materials, interior and exterior of automobiles, processing machines and vacuum ovens that perform heat treatment under low oxygen conditions, It is useful as a sealing material for plasma processing equipment, a heat dissipation component in processing units such as sputtering and various dry etching equipment, and an electromagnetic wave shield.

Molded articles such as sheets and laminates formed from the present composition are useful as electronic board materials such as flexible printed wiring boards and rigid printed wiring boards, protective films, and heat dissipation boards, particularly as heat dissipation boards for automobiles.
When using a sheet formed from the present composition as a TIM, the sheet may be directly attached to the target substrate, or it may be attached to the target substrate via an adhesive layer such as a silicone adhesive layer. It's okay.

The composition according to the second embodiment of the present invention (hereinafter also referred to as "second composition of the present invention") is a heat-melting tetrafluoroethylene polymer (hereinafter referred to as (also referred to as "F polymer"), a thermally conductive inorganic filler (hereinafter also referred to as "first filler") with an average particle diameter of 10 μm or more, and a thermally conductive filler (hereinafter also referred to as "first filler") with an average particle diameter of less than 2 μm. (hereinafter also referred to as "second filler").

The second composition of the present invention has excellent dispersibility, has high physical properties of the F polymer, the first filler, and the second filler, has excellent mechanical properties, heat resistance, linear expansion coefficient, dielectric constant, and dielectric constant. It has a low tangent, making it easy to form molded products such as sheets that have excellent thermal conductivity while maintaining electrical insulation. Although the reason is not necessarily clear, it is thought to be as follows.

F polymer has low affinity with other materials. Therefore, particularly in the case of a particulate filler such as the above-mentioned second filler, the second fillers tend to aggregate with each other in the composition, and not only is it difficult to exhibit its physical properties, but also the mechanical properties of the molded product obtained therefrom are etc. are also likely to decrease.
Therefore, in the second composition of the present invention, a first filler having a sufficiently large average particle diameter (D50) is used in combination with the second filler to promote interaction between the two fillers. In other words, it can be considered that aggregation of the second filler is suppressed by using the first filler as a base particle and having the second filler on the surface or in the vicinity thereof. When the fillers in the composition are in such a state, their surface areas are relatively increased, the interaction between each filler and the F polymer is promoted, and the uniform dispersibility of the composition is improved. it is conceivable that. In a molded article such as a sheet formed from such a composition, the second filler is efficiently and densely filled into the gap packed by the first filler, and a highly advanced filler path is likely to be formed, which leads to molding. It is thought that this improves thermal conductivity while maintaining the heat resistance, coefficient of linear expansion, and electrical properties of the material, especially electrical insulation. Furthermore, it is thought that the contact interface between the F polymer and the first filler and the second filler became larger, and the mechanical properties such as the bending strength of the molded product were also improved.

Such a tendency is achieved by setting the total amount of the first filler and the second filler to preferably more than 50% by volume in the total amount of the F polymer, the first filler, and the second filler, and making the total amount of the first filler and the second filler more than 50% by volume. This becomes even more noticeable when the amount of 1 filler is preferably more than 30% by volume.

The F polymer in the present invention includes a unit based on tetrafluoroethylene (hereinafter also referred to as "TFE") (hereinafter also referred to as "TFE unit"), and has a heat-melting property with a melting temperature of more than 100°C and 325°C or less. It is a polymer. Here, the term "thermofusible polymer" means a polymer that exists at a temperature at which the melt flow rate is 1 to 1000 g/10 minutes under a load of 49N.
The melting temperature of the F polymer is preferably 180°C or higher, more preferably 200°C or higher. The melting temperature of the F polymer is preferably 320°C or lower. In this case, the second composition of the present invention tends to have excellent processability, and the molded product formed from the second composition of the present invention tends to have excellent heat resistance.

The glass transition point of the F polymer is preferably 50°C or higher, more preferably 75°C or higher. The glass transition point of the F polymer is preferably 150°C or lower, more preferably 125°C or lower.
The fluorine content of the F polymer is preferably 70% by mass or more, more preferably 72 to 76% by mass.
The surface tension of the F polymer is preferably 16 to 26 mN/m. The surface tension of F polymer can be measured by placing droplets of a wet tension test mixture (manufactured by Wako Pure Chemical Industries, Ltd.) specified in JIS K 6768 on a flat plate made of F polymer. .

F polymers include polytetrafluoroethylene (PTFE), polymers containing TFE units and units based on ethylene (ETFE), polymers containing TFE units and units based on propylene, TFE units and perfluoro(alkyl vinyl ether) (PAVE) Polymers (PFA) containing units based on (PAVE units), polymers (FEP) containing TFE units and units based on hexafluoropropylene are preferred, PFA and FEP are more preferred, and PFA is even more preferred. These polymers may further contain units based on other comonomers.
PAVE is preferably CF ₂ =CFOCF ₃ , CF ₂ =CFOCF ₂ CF ₃ and CF ₂ =CFOCF ₂ CF ₂ CF ₃ (hereinafter also referred to as "PPVE"), and PPVE is more preferred.

The F polymer preferably has an oxygen-containing polar group, more preferably a hydroxyl group-containing group or a carbonyl group-containing group, and even more preferably a carbonyl group-containing group.
In this case, the F polymer tends to interact with the first filler and the second filler, and the second composition of the present invention tends to have excellent dispersibility. Further, from the second composition of the present invention, it is easy to obtain molded products such as sheets that have a low coefficient of linear expansion, a low dielectric constant, and a low dielectric loss tangent, and have excellent heat resistance and thermal conductivity.
The hydroxyl group-containing group is preferably a group containing an alcoholic hydroxyl group, more preferably -CF ₂ CH ₂ OH and -C(CF ₃ ) ₂ OH.
Carbonyl group-containing groups include carboxyl group, alkoxycarbonyl group, amide group, isocyanate group, carbamate group (-OC(O)NH ₂ ), acid anhydride residue (-C(O)OC(O)-), imide Residues (-C(O)NHC(O)-, etc.) and carbonate groups (-OC(O)O-) are preferred, and acid anhydride residues are more preferred.
When the F polymer has an oxygen-containing polar group, the number of oxygen-containing polar groups in the F polymer is preferably 10 to 5,000, more preferably 100 to 3,000 per 1×10 ⁶ carbon atoms in the main chain. Note that the number of oxygen-containing polar groups in the F polymer can be quantified by the composition of the polymer or the method described in International Publication No. 2020/145133.

The oxygen-containing polar group may be contained in a unit based on a monomer in the F polymer, or may be contained in a terminal group of the main chain of the F polymer, but the former is preferred. Examples of the latter embodiment include an F polymer having an oxygen-containing polar group as a terminal group derived from a polymerization initiator, a chain transfer agent, etc., and an F polymer obtained by subjecting the F polymer to plasma treatment or ionizing radiation treatment.
The monomer having a carbonyl group-containing group is preferably itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"), and more preferably NAH.

The F polymer is preferably a polymer having carbonyl group-containing groups, including TFE units and PAVE units, and includes units based on monomers having TFE units, PAVE units and carbonyl group-containing groups, and for the total units: More preferably, the polymer contains 90 to 99 mol%, 0.99 to 9.97 mol%, and 0.01 to 3 mol% of these units in this order. Specific examples of such F polymers include the polymers described in International Publication No. 2018/16644.

In the present invention, the F polymer is preferably included as particles (hereinafter also referred to as "F particles") having an average particle diameter (D50) of 0.1 μm or more and 25 μm or less. The F particles may be solid particles or pellets.
The D50 of the F particles is preferably 0.3 μm or more, more preferably 1 μm or more. D50 of the F particles is preferably less than 10 μm, more preferably 6 μm or less. In this case, the second composition of the present invention tends to have excellent dispersibility and processability. Further, from the second composition of the present invention, it is easy to obtain molded products such as sheets that have a low coefficient of linear expansion, a low dielectric constant, and a low dielectric loss tangent, and have excellent heat resistance and thermal conductivity.
The specific surface area of the F particles is preferably 1 to 25 m ² /g, more preferably 3 to 15 m ² /g.

The F particles are particles containing F polymer, and are preferably composed of F polymer.
More preferably, the F particles are particles of a heat-melting F polymer having an oxygen-containing polar group and having a melting temperature of 100 to 320°C. In this case, the above-mentioned mechanism of action is more fully expressed, and aggregation of F particles is more likely to be suppressed.
The F particles may contain a resin or an inorganic compound other than the F polymer, or may form a core-shell structure in which the F polymer is the core and the shell is a resin or inorganic compound other than the F polymer. A core-shell structure may be formed in which the shell is made of a resin other than F polymer or an inorganic compound is made of a core.
Here, examples of the resin other than the F polymer include aromatic polyester, polyamideimide, polyimide, and maleimide, and examples of the inorganic compound include silica and boron nitride.

One type of F particles may be used, or two or more types may be used.
Further, the F particles may be used in combination with particles of a non-thermofusible tetrafluoroethylene polymer. As the F particles, particles of a thermofusible F polymer having a melting temperature of 100 to 325°C are preferred, and particles of a thermofusible F polymer having a melting temperature of 180 to 320°C and having an oxygen-containing polar group are more preferred. As the non-thermo-fusible tetrafluoroethylene polymer particles, non-thermo-fusible PTFE particles are preferred. In this case, the agglomeration inhibiting effect of the heat-fusible F polymer particles and the retention effect of the fibrillation of the non-thermo-fusible tetrafluoroethylene polymer are balanced, and the dispersibility of the second composition of the present invention is likely to improve. . Moreover, in the molded article obtained therefrom, the electrical properties of the non-thermofusible tetrafluoroethylene polymer tend to be highly expressed.

The physical properties such as thermal conductivity and shape of each of the first filler and second filler included in the second composition of the present invention are the same as those in the first embodiment described above, including their preferred aspects. .
The specific example of the first filler, including its preferred aspects, is the same as the aspect of the first filler in the first embodiment described above.
The D50 of the first filler, including its suitable range, is the same as the aspect of the first filler in the first embodiment described above.
The surface aspect of the first filler, including its preferred aspect, is the same as the surface aspect of the first filler in the first embodiment described above.
The shape of the second filler, including its preferred aspect, is the same as the aspect of the first filler in the first embodiment described above.
The specific example of the second filler, including its preferred aspects, is the same as the aspect of the first filler in the first embodiment described above.
The D50 of the second filler, including its suitable range, is the same as the aspect of the first filler in the first embodiment described above.

In the second composition of the present invention, when the F polymer is contained as F particles, the ratio of D50 of the F particles to D50 of the first filler is preferably 1 or less, more preferably 0.1 or less. The above ratio is preferably 0.01 or more.
The ratio of D50 of the F particles to D50 of the second filler is preferably 20 or less, more preferably 10 or less. The above ratio is preferably 1 or more, more preferably 5 or more.

In the second composition of the present invention, the total amount of the first filler and the second filler in the total amount of the F polymer, the first filler, and the second filler is preferably more than 50 volume %, and is 55 volume % or more. is more preferable, and even more preferably 60% by volume or more. The total amount of the first filler and the second filler in the total amount of the F polymer, the first filler, and the second filler is preferably 75% by volume or less. Due to the above-mentioned mechanism of action, even when the total amount of fillers is within this range, the second composition of the present invention has excellent dispersibility, and the molded product thereof can be provided with a high degree of physical properties of each filler.

Furthermore, in the second composition of the present invention, the amount of the first filler in the total amount of the first filler and the second filler is preferably more than 30% by volume, more preferably more than 50% by volume, and 60% by volume. It is more preferable that the amount is % by volume or more. The amount of the first filler in the total amount of the first filler and the second filler is preferably 95% by volume or less, more preferably 90% by volume or less.
In this case, in the above-described working mechanism, it is likely that the second filler can be densely filled into the gap between the packings of the first filler. Furthermore, the interaction between different types of fillers increases, and aggregation of the first filler and the second filler is likely to be suppressed, and the dispersibility of the second composition of the present invention is likely to be improved.

The volume concentration of the F polymer (F particles), the volume concentration of the first filler, and the volume concentration of the second filler in the total volume of the F polymer (F particles), the first filler, and the second filler in the second composition of the present invention are preferably 10% to 60%, 30% to 80%, and 10% to 30% in this order.
When the volume concentration is within this range, the second composition of the present invention tends to have excellent dispersibility. Further, from the second composition of the present invention, it is easy to obtain a molded product such as a sheet having a low coefficient of linear expansion, a low dielectric constant, and a low dielectric loss tangent, and which has excellent thermal conductivity while maintaining electrical insulation.

The second composition of the present invention may further contain other resins different from the F polymer as long as the effects of the present invention are not impaired.
The manner in which other resins are included and their specific types, including their preferred aspects, are the same as those of the other resins in the first embodiment described above.

The second composition of the present invention may be in powder form, or may be in liquid form containing a liquid dispersion medium.
The aspects of the liquid dispersion medium, including its preferred aspects, are the same as those of the liquid dispersion medium in the first embodiment described above.

When the second composition of the present invention contains a liquid dispersion medium, the content of the liquid dispersion medium is the same as the content of the liquid dispersion medium in the first embodiment described above.

The second composition of the present invention, particularly the second composition of the present invention containing a liquid dispersion medium, further has a nonionic surfactant from the viewpoint of improving the dispersion stability of the F polymer (F particles), the first filler, and the second filler. It is preferable to include an agent.
The aspects of the nonionic surfactant, including its preferred aspects, are the same as those of the nonionic surfactant in the first embodiment described above.

The second composition of the present invention further includes a thixotropic agent, a viscosity modifier, an antifoaming agent, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a whitening agent, It may contain additives such as colorants, conductive agents, mold release agents, and flame retardants.

When the second composition of the present invention is liquid and contains a liquid dispersion medium, its viscosity is preferably 10 mPa·s or more, more preferably 100 mPa·s or more. The viscosity of the second composition of the present invention is preferably 10,000 mPa·s or less, more preferably 3,000 mPa·s or less.
When the second composition of the present invention is liquid and contains a liquid dispersion medium, its thixotropic ratio is preferably 1.0 to 3.0.

The second composition of the present invention is obtained by mixing the F polymer (F particles), the first filler, the second filler, and other resins, liquid dispersion medium, surfactant, additives, etc. as necessary. .
The second composition of the present invention may be obtained by mixing the F polymer (F particles), the first filler, and the second filler all at once, or may be obtained by mixing them separately in sequence, or by preparing these master batches in advance. may be prepared and mixed with the remaining ingredients. There is no particular restriction on the order of mixing, and the mixing method may be all at once or divided into multiple batches.
As the mixing device, the same device as described above can be mentioned.

The method for producing the second composition of the present invention containing a liquid dispersion medium includes first adding the first filler to the liquid dispersion medium containing the F polymer (F particles), and then adding and mixing the second filler. This is preferable from the viewpoint of improving the dispersibility of the F particles, the first filler, and the second filler.
More specifically, the F polymer (F particles) and a part of the liquid dispersion medium are kneaded in advance, then the first filler and the second filler are sequentially added and kneaded, and the resulting kneaded product is mixed with the remaining A manufacturing method for obtaining the second composition of the present invention by adding it to a liquid dispersion medium can be mentioned. The liquid dispersion medium used during kneading and addition may be the same type of liquid dispersion medium or may be different types of liquid dispersion medium. Other resins, surfactants, and additives may be mixed during kneading or may be mixed during addition.

Mixing during kneading is preferably performed using a planetary mixer.
Mixing during addition is preferably carried out using a thin film swirling type high speed mixer. A thin film swirl type high speed mixer spreads a kneaded material containing F polymer (F particles), a first filler and a second filler, and a liquid dispersion medium in a thin film shape on the inner wall surface of a cylindrical stirring tank and swirls the mixer. This is a stirring device that mixes while applying centrifugal force.

From the second composition of the present invention, it is easy to obtain a molded product having a thermal conductivity of 10 W/m·K or more. The thermal conductivity of such a molded article is preferably 10 to 100 W/m·K.
The dielectric constant of the molded product obtained from the second composition of the present invention is preferably 2.4 or less, more preferably 2.0 or less. Moreover, it is preferable that the dielectric constant is more than 1.0. The dielectric loss tangent of the molded product is preferably 0.0022 or less, more preferably 0.0020 or less. Moreover, it is preferable that the dielectric loss tangent is more than 0.0010.

When the second composition of the present invention is subjected to a molding method such as extrusion, a molded product such as a sheet containing the F polymer, the first filler, and the second filler can be obtained.
When the second composition of the present invention contains a liquid dispersion medium and is in liquid form, it is preferable to extrude the second composition of the present invention into a sheet form. The sheet obtained by extrusion may be further subjected to press molding, calendar molding, etc. and then cast. Preferably, the sheet is further heated to remove the liquid dispersion medium and sinter the F polymer.
When the second composition of the present invention is in powder form, it is preferable to melt-extrude the second composition of the present invention. Extrusion molding can be performed using a single screw extruder, a multi-screw extruder, or the like.
Alternatively, a molded article may be obtained by injection molding the second composition of the present invention.
When forming a molded article, the second composition of the present invention may be directly melt-extruded or injection molded, or the second composition of the present invention may be melt-kneaded to form pellets, and the pellets may be melt-extruded or injection molded. A molded product such as a sheet may also be obtained.

The thickness of the sheet obtained from the second composition of the present invention is preferably 50 μm or more, more preferably 75 μm or more, and even more preferably 100 μm or more. The thickness of the sheet is preferably 1000 μm or less.
The preferable ranges of the thermal conductivity, dielectric constant, and dielectric loss tangent of the sheet are the same as the ranges of the thermal conductivity, dielectric constant, and dielectric loss tangent of the molded article, respectively. Note that the thermal conductivity of the sheet means the thermal conductivity in the in-plane direction of the sheet.
The coefficient of linear expansion of the sheet is preferably 100 ppm/°C or less, more preferably 80 ppm/°C or less. The lower limit of the linear expansion coefficient of the sheet is 30 ppm/°C. Note that the linear expansion coefficient means a value obtained by measuring the linear expansion coefficient of a test piece in the range of 25° C. or higher and 260° C. or lower according to the measurement method specified in JIS C 6471:1995.

A laminate can be formed by laminating such sheets on a base material. The method for producing the laminate includes a method of extruding the second composition of the present invention together with a raw material for the base material using a coextruder as the extruder, and a method of extruding the second composition of the present invention onto the base material. Examples include a method of thermocompression bonding the sheet and the base material, and the like.
As a base material, metal substrates such as metal foils such as copper, nickel, aluminum, titanium, and alloys thereof; polyester, polyimide, polyamide, polyetheramide, polyphenylene sulfide, polyallyletherketone, polyamideimide, liquid crystalline polyester, Suitable examples include films of heat-resistant resins such as tetrafluoroethylene polymers; prepreg substrates (precursors of fiber-reinforced resin substrates); ceramic substrates such as silicon carbide, aluminum nitride, and silicon nitride; and glass substrates.

By disposing the second composition of the present invention on the surface of the base material and forming a polymer layer containing the F polymer, the first filler, and the second filler, the base material layer and the polymer layer composed of the base material can be separated. A laminate having the following properties is obtained. The polymer layer is preferably formed by disposing the second composition of the present invention containing a liquid dispersion medium on the surface of the substrate, heating to remove the dispersion medium, and further heating to bake the F polymer. By separating the base material from such a laminate, a sheet containing the F polymer, the first filler, and the second filler can be obtained.
Examples of the base material include those similar to those that can be laminated with the sheet described above, and preferred embodiments thereof are also the same.

Examples of the method for disposing the second composition of the present invention include a coating method, a droplet discharge method, and a dipping method, and preferred are a roll coating method, a knife coating method, a bar coating method, a die coating method, and a spray method.
Heating during removal of the liquid dispersion medium is preferably carried out at 100 to 200° C. for 0.1 to 30 minutes. In this heating, the liquid dispersion medium does not need to be completely removed, but may be removed to the extent that the layer formed by packing the F particles, the first filler, and the second filler can maintain a self-supporting film. Furthermore, during heating, air may be blown to encourage removal of the liquid dispersion medium by air drying.

Heating during firing of the F polymer is preferably carried out at a temperature equal to or higher than the firing temperature of the F polymer, more preferably at 360 to 400°C for 0.1 to 30 minutes.
Examples of heating devices for each heating include an oven and a ventilation drying oven. The heat source in the device may be a contact heat source (hot air, hot plate, etc.) or a non-contact heat source (infrared rays, etc.).
Moreover, each heating may be performed under normal pressure or under reduced pressure.
Further, the atmosphere in each heating may be an air atmosphere or an inert gas (helium gas, neon gas, argon gas, nitrogen gas, etc.) atmosphere.

The polymer layer is formed through the steps of disposing and heating the second composition of the present invention. These steps may be performed once or may be repeated two or more times. For example, the second composition of the present invention is placed on the surface of a base material and heated to form a polymer layer, and the second composition of the present invention is further placed on the surface of the polymer layer and heated to form a second polymer layer. may be formed. Further, at the stage where the second composition of the present invention is placed on the surface of the base material and heated to remove the liquid dispersion medium, the second composition of the present invention is further placed on the surface and heated to form a polymer layer. Good too.
The second composition of the present invention may be placed only on one surface of the base material, or may be placed on both sides of the base material. In the former case, a laminate is obtained that has a base layer and a polymer layer on one surface of the base layer, and in the latter case, a laminate is obtained that has a base layer and a polymer layer on both surfaces of the base layer. A laminate is obtained.

Preferred specific examples of the laminate include a metal clad laminate having a metal foil and a polymer layer on at least one surface of the metal foil, and a multilayer film having a polyimide film and a polymer layer on both surfaces of the polyimide film. can be mentioned.
Preferred ranges of the thickness of the polymer layer, thermal conductivity, dielectric constant, dielectric loss tangent, coefficient of linear expansion, and peel strength between the polymer layer and the base material layer are the thickness of the sheet obtained from the second composition of the present invention described above. The preferred ranges are the same as those for thermal conductivity, dielectric constant, dielectric loss tangent, coefficient of linear expansion, and peel strength between the sheet and the base material.

The second composition of the present invention is useful as a material for imparting insulation, heat resistance, corrosion resistance, chemical resistance, water resistance, impact resistance, and thermal conductivity.
Specific uses include the use of the composition in the first embodiment described above.

The present invention is also a thermal interface material (TIM) containing the second composition of the present invention. The TIM containing the second composition of the present invention has the physical properties of the F polymer, the first filler, and the second filler to a high degree, has excellent mechanical properties and heat resistance, and has low linear expansion coefficient, dielectric constant, and dielectric loss tangent. It has low heat conductivity and particularly excellent thermal conductivity.
Examples of the TIM use of the second composition of the present invention include the TIM use of the composition in the first embodiment described above.

The present invention also provides a sheet containing an F polymer, a first filler, and a second filler. Details of the F polymer, the first filler, the second filler, and other optional constituent components in such a sheet are the same as those described above in the description of the second composition of the present invention.
Such a sheet is preferably formed from the second composition of the present invention by the method described above. The preferable ranges of the sheet thickness, thermal conductivity, dielectric constant, dielectric loss tangent, and coefficient of linear expansion are the same as described above.
Such a sheet can be suitably used as a TIM.

Molded products such as sheets and laminates formed from the second composition of the present invention are useful as antenna parts, printed circuit boards, aircraft parts, automobile parts, sports equipment, food industry products, heat dissipation parts, and the like.
Specific uses are the same as those of the composition in the first embodiment described above.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.
1. Preparation of each component [fluoroelastomer, F polymer]
F elastomer 1: TFE/P-containing polymer. Product name “AFLAS (registered trademark) 400E” (manufactured by AGC)
F polymer 1: Contains 97.9 mol%, 0.1 mol%, and 2.0 mol% of TFE units, NAH units, and PPVE units in this order, and carbonyl group-containing groups per 1 × 10 ⁶ main chain carbon atoms. Tetrafluoroethylene polymer with 1000 polymers (melting temperature: 300°C)
《Preparation of fluoroelastomer solution》
Fluoroelastomer solution 1 was prepared by adding 40 parts by mass of F elastomer 1 into 60 parts by mass of butyl acetate (manufactured by Kanto Kagaku Co., Ltd., Shika 1 grade) and stirring at 25°C for 30 hours or more, which was used in the following example. .
<<Preparation of dispersion containing particles of F polymer>>
Dispersion liquid 1 in which particles of F polymer 1 (D50: 2.1 μm, non-hollow) are dispersed in N-methylpyrrolidone, containing 50% by mass of particles of F polymer 1, and using N-methylpyrrolidone as a dispersion medium was prepared and used in the following examples.
[Thermally conductive inorganic filler]
Boron nitride 1: Trade name "HP-40MF100" (manufactured by JFE Mineral Co., Ltd., D50: 36 μm, agglomerated structure)
Boron nitride 2: Product name "HP-40J2" (manufactured by JFE Minerals, D50: 16 μm, agglomerated structure)
Aluminum nitride 1: High purity aluminum nitride (D50: 30 μm, agglomerated structure)
[Thermal conductive filler]
Alumina 1: Product name "TM-5D" (manufactured by Daimei Chemical Industry Co., Ltd., D50: 0.2 μm, oval shape)
Alumina 2: Product name “Alunabeads (registered trademark) CB-P02” (manufactured by Showa Denko, D50: 2 μm, spherical structure)
Aluminum nitride 2: High purity aluminum nitride (manufactured by Tokuyama, D50: 1 μm, oval shape)

2-1. Production example of composition [Example 1]
53.8 parts by mass of fluoroelastomer solution 1 was added to 7.7 parts by mass of butyl acetate, and then 32.4 parts by mass of boron nitride 1 was added as a thermally conductive inorganic filler. After kneading for 1 minute at 2000 rpm using Awatori Rentaro (registered trademark) ARE-310 (trade name), the mixture was defoamed at 2000 rpm for 3 minutes. Thereafter, 6.1 parts by mass of alumina 1 was added as a thermally conductive filler, and after kneading for 1 minute at 2000 rpm using a rotation-revolution mixer, degassing treatment was performed at 2000 rpm for 3 minutes to obtain composition 1. Ta. Composition 1 was in the form of a slurry, and in the solid content of Composition 1, F elastomer 1 was 45% by volume, boron nitride 1 was 50% by volume, and alumina 1 was 5% by volume.
[Examples 2 to 15]
The types of thermally conductive inorganic filler and thermally conductive filler used were changed as shown in Table 1, and the volume ratios of F elastomer 1, thermally conductive inorganic filler, and thermally conductive filler were changed as shown in Table 1. Except for this, Compositions 2 to 15 were obtained in the same manner as in Example 1.

3. Manufacture of Sheet Composition 1 was applied to the surface of a polyethylene terephthalate (PET) substrate using an applicator to form a wet film. Next, the PET substrate on which this wet film was formed was dried in a drying oven at 140° C. for 1 hour to form a dry film. Thereafter, the dry film was peeled off from the PET substrate to produce Sheet 1.
Sheets 2 to 15 were produced from compositions 2 to 15 in the same manner as sheet 1.

4. Evaluation 4-1. Sheet Thickness The thickness of each sheet was measured using a micrometer.
4-2. Thermal conductivity of the sheet A 10 mm x 10 mm square test piece was cut out from each sheet, and the thermal conductivity (W/m・K) in the in-plane direction was measured using a xenon flash analyzer (LFA467 HyperFlash manufactured by Netsch). , measured at 25°C. Furthermore, the density required for calculating the thermal conductivity was obtained by dividing the mass by the volume measured by a micrometer.
The above results are summarized in Tables 1 and 2.

As is clear from the above results, the sheets formed from the compositions of Examples 1 to 4, Examples 8 to 9, and Examples 13 to 14, which satisfy the provisions of the present invention, have excellent thermal conductivity, and have excellent electrical insulation and compatibility. It also had excellent bendability.
5. Manufacturing example of the second composition (manufacturing example of the second composition of the present invention)
[Example 21]
31.0 parts by mass of F particle 1 dispersion was added to 24.5 parts by mass of N-methylpyrrolidone, then 25.4 parts by mass of boron nitride was added as a thermally conductive inorganic filler, and then 25.4 parts by mass of boron nitride was added as a thermally conductive filler. 19.1 parts by mass of Alumina 1 was added and mixed for 1 minute at 2000 rpm using a rotation and revolution mixer (manufactured by Shinky Co., Ltd., trade name "Awatori Rentaro (registered trademark) ARE-310") to obtain Composition 21. Obtained. Composition 21 was in the form of a slurry, and the solid content of Composition 21 contained 30% by volume of F particles 1, 50% by volume of boron nitride, and 20% by volume of alumina 1.
[Examples 22-23]
Compositions 22 to 23 were obtained in the same manner as in Example 21, except that the volume ratios of F particles 1, boron nitride, and alumina 1 were changed as shown in Table 3.

6. Manufacture of Sheet Composition 1 was applied to the surface of a copper foil having a thickness of 0.2 μm using an applicator to form a wet film. Next, the glass substrate on which the wet film was formed was dried by passing it through a drying oven at 120° C. for 3 minutes to form a dry film.
Furthermore, the copper foil substrate having the dry film was cut into a size of 3 cm x 3 cm, and hot pressed at 340° C. and 10 MPa for 3 minutes. Thereafter, the copper foil was removed by immersing it in a ferric chloride aqueous solution for 2 hours to obtain a sheet 21.
Sheets 22-23 were produced from compositions 22-23 in the same manner as sheet 21.

7. Rating 7-1. Thickness of Sheet The thickness of each sheet and its thermal conductivity were measured by the method described above. The above results are summarized in Table 3.

As is clear from the above results, the sheet formed from the composition of the example satisfying the provisions of the present invention had excellent thermal conductivity, and was also excellent in electrical insulation and bendability.

The composition of the present invention and the sheet formed from the composition of the present invention highly exhibit the physical properties of the fluoroelastomer, thermally conductive inorganic filler, and thermally conductive filler, and have thermal conductivity, heat resistance, and electrical insulation properties. It is excellent and can be effectively used as a thermal interface material.
The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2022-092826 and Japanese Patent Application No. 2022-092827 filed on June 8, 2022 are cited here, and the present invention is It is hereby incorporated by reference as disclosure in the specification.

Claims

A fluoroelastomer or a heat-melting tetrafluoroethylene polymer with a melting temperature of more than 100°C and 325°C or less,
A thermally conductive inorganic filler having an average particle size of 10 μm or more,
A composition comprising: a thermally conductive filler having an average particle diameter of less than 2 μm.
The composition according to claim 1, comprising the fluoroelastomer, the thermally conductive inorganic filler having an average particle size of 10 μm or more, and the thermally conductive filler having an average particle size of less than 2 μm.
The composition according to claim 2, wherein the total amount of the thermally conductive inorganic filler and the thermally conductive filler in the total amount of the fluoroelastomer, the thermally conductive inorganic filler, and the thermally conductive filler is more than 50% by volume. thing.
The composition according to claim 2, wherein the amount of the thermally conductive inorganic filler in the total amount of the thermally conductive inorganic filler and the thermally conductive filler is more than 30% by volume.
The composition according to claim 2, wherein the thermally conductive filler has an average particle diameter of more than 0.05 μm and less than 1 μm.
The composition according to claim 2, wherein the thermally conductive inorganic filler is boron nitride, aluminum nitride, silicon nitride, or aluminum oxide.
The composition according to claim 2, wherein the thermally conductive filler is aluminum oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, carbon fiber, graphite, graphene, carbon nanotubes, silver, or copper.
A sheet containing a fluoroelastomer, a thermally conductive inorganic filler with an average particle size of 10 μm or more, and a thermally conductive filler with an average particle size of less than 2 μm.
The heat-melting tetrafluoroethylene polymer having a melting temperature of more than 100° C. and 325° C. or less, the thermally conductive inorganic filler having an average particle size of 10 μm or more, and the thermally conductive filler having an average particle size of less than 2 μm. The composition according to claim 1, comprising:
A total amount of the thermally conductive inorganic filler and the thermally conductive filler in the total amount of the thermally meltable tetrafluoroethylene polymer, the thermally conductive inorganic filler, and the thermally conductive filler is more than 50% by volume. The composition according to item 9.
The composition according to claim 9, wherein the amount of the thermally conductive inorganic filler in the total amount of the thermally conductive inorganic filler and the thermally conductive filler is more than 30% by volume.
The composition according to claim 9, wherein the thermally conductive filler has an average particle diameter of more than 0.05 μm and less than 1 μm.
The composition according to claim 9, wherein the thermally conductive inorganic filler is boron nitride, aluminum nitride, silicon nitride, or aluminum oxide.
The composition according to claim 9, wherein the thermally conductive filler is aluminum oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, carbon fiber, graphite, graphene, carbon nanotubes, silver, or copper.
Contains a heat-melting tetrafluoroethylene polymer with a melting temperature of more than 100°C and 325°C or less, a thermally conductive inorganic filler with an average particle size of 10 μm or more, and a thermally conductive filler with an average particle size of less than 2 μm. , sheet.