Composition

Abstract

This invention provides a composition comprising, in a specific ratio, particles of a tetrafluoroethylene-based polymer, hollow particles, and particles of a specific inorganic compound, capable of forming a molded article with excellent dispersibility, low coefficient of linear expansion, low dielectric constant, and low dielectric loss tangent, as well as excellent thermal conductivity and adhesion. The composition of this invention comprises: a first particle of a tetrafluoroethylene-based polymer, a second hollow particle, and a third particle of an inorganic compound with an aspect ratio greater than 1, wherein the volume concentration ratio of the first particle to the second particle is greater than 1, and the volume concentration ratio of the third particle to the second particle is less than 0.6.

Description

Technical Field

[0001] This invention relates to a specific composition comprising: a first particle of a tetrafluoroethylene-based polymer, a hollow second particle, and a third particle of an inorganic compound having an aspect ratio greater than 1. Prior Technology

[0002] In recent years, in order to cope with the increasing speed and frequency of mobile communication devices such as mobile phones, the materials of printed circuit boards for communication devices have been sought to be high thermal conductivity, low coefficient of linear expansion, low dielectric constant and low dielectric loss tangent. As a result, tetrafluoroethylene-based polymers with low dielectric constant and low dielectric loss tangent have attracted attention. In order to obtain materials with better physical properties, the composition of tetrafluoroethylene-based polymers with other components is studied. Patent Document 1 proposes a powder composition of tetrafluoroethylene-based polymer particles and boron nitride particles. Previous technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-224228 Summary of the Invention

[0004] [The problem the invention aims to solve]

[0005] Tetrafluoroethylene-based polymers have low surface tension and low affinity for other components. Therefore, in molded articles formed from compositions containing tetrafluoroethylene-based polymers and other components, the physical properties of each component are not fully expressed. The inventors have found that it is difficult to obtain compositions capable of forming molded articles with low coefficients of linear expansion and excellent electrical properties, thermal conductivity, and adhesion; more specifically, it is difficult to obtain compositions capable of forming molded articles possessing these properties and with sufficiently low dielectric loss tangent. The inventors have discovered that compositions comprising particles of a tetrafluoroethylene-based polymer, hollow particles, and particles of a specific inorganic compound in a specific ratio exhibit excellent dispersibility, low coefficient of linear expansion, low dielectric constant, and low dielectric loss tangent in their molded articles, and excellent thermal conductivity and adhesion, especially with a low dielectric loss tangent, thereby completing the present invention. The object of this invention is to provide this composition. [Technical means to solve the problem]

[0006] The present invention has the following form. [1] A composition comprising: a first particle of a tetrafluoroethylene polymer, a second particle of hollow structure, and a third particle of an inorganic compound having an aspect ratio greater than 1, wherein the volume concentration of the first particle is greater than 1 relative to the volume concentration of the second particle, and the volume concentration of the third particle is less than 0.6 relative to the volume concentration of the second particle. [2] The composition as described in [1], wherein, relative to the total volume of the first particle, the second particle and the third particle, the volume concentration of the first particle, the second particle and the third particle are 40-70%, 20-50% and 5% or more but less than 30%, respectively. [3] The composition as in [1] or [2], wherein the first particle is a particle of a thermomeltable tetrafluoroethylene polymer, and the thermomeltable tetrafluoroethylene polymer is a thermomeltable tetrafluoroethylene polymer with an oxygen-containing polar group having a melting temperature of 200~320°C. [4] The composition of any one of [1] to [3] comprises particles of a hot-melt tetrafluoroethylene polymer and particles of a non-hot-melt tetrafluoroethylene polymer as the first particle mentioned above. [5] The composition of any one of [1] to [4], wherein the average particle size of the first particle is 0.01 μm or more and less than 10 μm.

[0007] [6] The composition of any one of [1] to [5], wherein the second particle is a hollow silicon dioxide particle or a hollow glass particle. [7] The composition of any one of [1] to [6], wherein the average particle size of the second particle is 1 to 100 μm. [8] A composition of any one of [1] to [7], wherein the third particle is a boron nitride particle, a silicon nitride particle or an aluminum nitride particle. [9] The composition of any one of [1] to [8], wherein the average particle size of the third particle is 1 to 50 μm.

[10] A composition of any one of [1] to [9], wherein the third particle is a particle that has been surface-treated with a silane coupling agent.

[0008]

[11] The composition of any one of [1] to

[10] , wherein the average particle size of the first particle is smaller than either the average particle size of the second particle or the average particle size of the third particle.

[12] The composition of any one of [1] to

[11] , wherein the ratio of the average particle size of the second particle to the average particle size of the third particle is 0.5 to 3.

[13] The composition of any one of [1] to

[12] is used to obtain a molded article having a dielectric constant of 2.8 or less and a dielectric loss tangent of 0.0025 or less.

[14] A method for manufacturing a sheet, wherein a composition as described in any one of [1] to

[13] above is extruded to obtain a sheet comprising the above-described tetrafluoroethylene polymer, the above-described second particle and the above-described third particle.

[15] A method for manufacturing a laminate, wherein a composition as described in any one of [1] to

[13] is disposed on the surface of a substrate to form a polymer layer comprising the tetrafluoroethylene polymer, the second particle and the third particle, thereby obtaining a laminate having a substrate layer comprising the substrate and the polymer layer. [Effects of the Invention]

[0009] According to the present invention, a composition comprising particles of a tetrafluoroethylene-based polymer, hollow particles, and particles of a specific inorganic compound, and exhibiting excellent dispersibility is provided. This composition can be used to form molded articles with low coefficients of linear expansion, low dielectric constants and dielectric loss tangents, excellent thermal conductivity and adhesion, and particularly low dielectric loss tangents. Implementation

[0010] The following terms have the following meanings. "Average particle size (D50)" is the particle size at 50% of the volume reference obtained by laser diffraction scattering. That is, in order to determine the particle size distribution by laser diffraction scattering, the total volume of the particle cluster is set to 100%, and a cumulative curve is obtained. The particle size at the point where the cumulative volume is 50% on the cumulative curve is the particle size. The D50 of the particles is determined by dispersing the particles in water and analyzing them using a laser diffraction particle size distribution measuring device (manufactured by Horiba Corporation, LA-920 measuring instrument). "D90" refers to the cumulative volumetric particle size, which is the cumulative 90% particle size based on the volumetric reference of the particle, obtained in the same way as "D50". "Melting temperature" refers to the temperature corresponding to the maximum value of the polymer's melting peak as measured by differential scanning calorimetry (DSC). The "glass transition point (Tg)" is a value obtained by analyzing and measuring polymers using the dynamic viscoelasticity assay (DMA). "Viscosity" was determined using a Type B viscometer at 25°C and a rotation speed of 30 rpm. The measurement was repeated three times, and the average of the three measurements was used. The "thixotropic ratio" is calculated by dividing the viscosity η1 of the composition measured at 30 rpm by the viscosity η2 measured at 60 rpm. Each viscosity measurement was performed three times, and the average of the three measurements was used. In polymers, a "unit" refers to a group of atoms of a monomer formed by the polymerization of a monomer into a single molecule. A unit can be formed directly through a polymerization reaction, or it can be a unit whose structure is partially transformed by processing the polymer. Hereinafter, units based on monomer a will be abbreviated as "monomer a unit".

[0011] The composition of the present invention (hereinafter also referred to as "the composition") comprises: a first particle of a tetrafluoroethylene-based polymer (hereinafter also referred to as "F polymer"), a hollow second particle, and a third particle of an inorganic compound with an aspect ratio greater than 1. The volume concentration ratio of the first particle to the second particle is greater than 1, and the volume concentration ratio of the third particle to the second particle is less than 0.6.

[0012] This composition exhibits excellent dispersibility, readily forming molded articles that possess the properties of the F polymer, the second particle, and the third particle, with low coefficients of linear expansion, dielectric constant, and dielectric loss tangent, excellent thermal conductivity and adhesion, and particularly low dielectric loss tangent. The reasons for this are not necessarily clear, but are believed to be as follows.

[0013] Hollow particles, due to the air they contain, reduce the dielectric constant and dielectric loss tangent of the molded article containing them. However, they are also prone to breakage, making it difficult to fully express their physical properties in the molded article. Therefore, in this composition, the volume concentration of low-hardness and low-slip polymer F particles (first particles) is higher than the volume concentration of hollow particles (second particles). In this composition, the first particles buffer the stress applied to the second particles, suppressing breakage of the second particles. In particular, this suppression effect becomes more pronounced when this composition is processed and molded. Furthermore, this composition contains inorganic compound particles (third particles) with an aspect ratio greater than 1 at a volume concentration relative to the second particles that does not reach a specific ratio. It is believed that the insufficient content of the third particles makes them less prone to aggregation, resulting in a state where they are easily and uniformly dispersed with the first and second particles. Moreover, it is also believed that when this composition is processed and molded, the dense filling of the excessively contained second particles promotes the highly oriented configuration of the third particles in the molded article; in other words, it promotes the formation of thermally conductive channels for the third particles in the molded article. The results suggest that the composition yields molded articles with high physical properties of the F polymer, the second particle, and the third particle; specifically, with low coefficient of linear expansion, dielectric constant, and dielectric loss tangent, as well as excellent thermal conductivity and adhesion.

[0014] The F polymer system in this invention comprises polymers based on tetrafluoroethylene (hereinafter also referred to as "TFE unit") units. The F polymer can be heat-melt or non-heat-melt. Thermomeltable polymers refer to polymers that, under a load of 49 N, exhibit a melt flow rate of 1 to 1000 g / 10 minutes. Non-meltable polymers refer to polymers that do not exhibit a melt flow rate of 1-1000 g / 10 minutes under a load of 49 N. The melting temperature of the hot-melt polymer F is preferably 200°C or higher, and more preferably 260°C or higher. The melting temperature of the aforementioned polymer F is preferably 325°C or lower, and more preferably 320°C or lower. The melting temperature of the aforementioned polymer F is preferably 200~320°C. Under these conditions, the processability of the composition is easily improved, and the heat resistance of the molded article formed from the composition is easily improved.

[0015] The glass transition point of polymer F is preferably above 50°C, and more preferably above 75°C. The glass transition point of polymer F is preferably below 150°C, and more preferably below 125°C. The fluorine content of polymer F is preferably 70% by mass or more, and more preferably 72-76% by mass. The surface tension of polymer F is preferably 16~26 mN / m. Furthermore, the surface tension of polymer F can be measured by placing droplets of a wetting tension test mixture (manufactured by Wako Pure Chemical Industries Co., Ltd.) as specified in JIS K 6768 on a plate made of polymer F.

[0016] The polymer F is preferably polytetrafluoroethylene (PTFE), a polymer containing TFE units and ethylene-based units, a polymer containing TFE units and propylene-based units, a polymer containing TFE units and perfluoro(alkyl vinyl ether) (PAVE)-based units (PAVE units) (PFA), a polymer containing TFE units and hexafluoropropylene-based units (FEP), more preferably PFA and FEP, and even more preferably PFA. These polymers may further contain units based on other comonomers. PAVE is preferably CF 2=CFOCF 3, CF 2=CFOCF 2CF 3 and CF 2=CFOCF 2CF 2CF 3 (hereinafter also referred to as "PPVE"), and even better is PPVE.

[0017] The F polymer preferably has an oxygen-containing polar group, more preferably has a hydroxyl-containing group or a carbonyl-containing group, and even more preferably has a carbonyl-containing group. In this case, the first particle easily interacts with the second and third particles, resulting in excellent dispersibility of the composition. Furthermore, this composition readily yields molded articles with low coefficients of linear expansion, dielectric constants, and dielectric loss tangents, as well as excellent thermal conductivity and adhesion. The hydroxyl group is preferably an alcoholic hydroxyl group, and more preferably -CF2CH2OH and -C(CF3)2OH. The carbonyl group is preferably a carboxyl group, alkoxycarbonyl group, amide group, isocyanate group, carbamate group (-OC(O)NH 2), acid anhydride residue (-C(O)OC(O)-), amide imine residue (-C(O)NHC(O)-, etc.) and carbonate group (-OC(O)O-), and more preferably an acid anhydride residue. When polymer F contains oxygen-containing polar groups, the number of oxygen-containing polar groups in polymer F is preferably 10 to 5000 per 1 × 10⁶ carbons in the main chain, and more preferably 100 to 3000. Furthermore, the number of oxygen-containing polar groups in polymer F can be quantified by the composition of the polymer or by the method described in International Publication No. 2020 / 145133.

[0018] The oxygen-containing polar group can be contained in the monomer-based unit of the F polymer, or it can be contained in the terminal group of the F polymer backbone, with the former being preferred. Examples of the latter include: F polymers having oxygen-containing polar groups as terminal groups derived from polymerization initiators, chain transfer agents, etc.; and F polymers obtained by plasma treatment or ionizing radiation treatment of F polymers. Monomers containing a carbonyl group are preferably itanic anhydride, citric anhydride and 5-norconene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"), and more preferably NAH.

[0019] Polymer F is preferably a polymer containing carbonyl groups, comprising TFE units and PAVE units, and more preferably a polymer comprising TFE units, PAVE units, and units based on monomers containing carbonyl groups, and comprising, in sequence, 90-99 mol%, 0.99-9.97 mol%, and 0.01-3 mol% of these units relative to all units. As a specific example of polymer F, the polymer described in International Publication No. 2018 / 16644 can be cited.

[0020] The first particle in this invention is a particle of polymer F, and is not a hollow particle. The first particle can also be granular. The D50 of the first particle is preferably 0.01 μm or more, more preferably 0.3 μm or more, and even more preferably 1 μm or more. The D50 of the first particle is preferably less than 10 μm, more preferably less than 8 μm. Under these conditions, the dispersibility and processability of the composition are easily improved. Furthermore, this composition readily yields molded articles with low coefficients of linear expansion, low dielectric constants and low dielectric loss tangents, and excellent thermal conductivity and adhesion. The preferred specific surface area of ​​the first particle is 1~25 m2 / g.

[0021] The first particle is preferably a particle of a thermoplastic F polymer, and more preferably a particle of a thermoplastic F polymer with an oxygen-containing polar group and a melting temperature of 200~320℃. In this situation, the stress buffering effect of the first particle in the above-mentioned mechanism is easily enhanced. Furthermore, the interaction between dissimilar particles is improved, the aggregation of individual particles is easily suppressed, and the dispersibility of this composition is easily improved.

[0022] This composition may contain two or more types of first particles. Specifically, examples include: compositions containing two or more first particles of different F polymers; compositions containing two or more first particles with different amounts of or types of the following byproducts; and compositions containing first particles from two or more first particle powders with different D50 values. As a form in which this composition contains two or more types of first particles, it is preferable to have a composition containing two or more first particles of different F polymers. When the composition comprises two or more first particles of different F polymers, at least one of the two or more first particles is preferably a particle of the aforementioned thermoplastic F polymer.

[0023] When the composition contains two types of first particles, it is preferable that the composition contains both hot-melt F polymer particles and non-hot-melt F polymer particles as first particles. In this case, the buffering and agglomeration inhibition effects of the second particles caused by the hot-melt F polymer particles are balanced with the retention effects of the second and third particles caused by the fibrillation of the non-hot-melt F polymer, thus easily improving the dispersibility of the composition. Furthermore, the resulting molded articles exhibit the high electrical properties of the non-hot-melt F polymer, making it easy to obtain molded articles with particularly low dielectric loss tangent. The particles of the former are preferably particles of a thermoplastic F polymer with a melting temperature of 200-320°C, and more preferably particles of a thermoplastic F polymer with a melting temperature of 200-320°C and containing oxygen-containing polar groups. The suitable morphology of the thermoplastic F polymer with oxygen-containing polar groups in the former particles is the same as the suitable morphology of the F polymer with oxygen-containing polar groups mentioned above. The particles used in the latter category are preferably non-thermally fusible PTFE particles. Furthermore, relative to the total volume of the two types of first particles, the volume concentration of the former particles is preferably 50% or less, and more preferably 25% or less. Also, the aforementioned volume concentration is preferably 0.1% or more, and more preferably 1% or more. Furthermore, the D50 of the former particles is preferably 1~4 μm, and the D50 of the latter particles is preferably 0.1~1 μm.

[0024] The first particle is a particle containing F polymer, preferably containing F polymer. The first particle may contain resin or inorganic compounds other than F polymer, and may form a core-shell structure with F polymer as the core and resin or inorganic compounds other than F polymer as the shell, or may form a core-shell structure with F polymer as the shell and resin or inorganic compounds other than F polymer as the core. Examples of resins other than polymer F include: aromatic polyesters, polyamide imides, polyimides, and maleimides. Examples of inorganic compounds include: silicon dioxide and boron nitride.

[0025] The second particle in this invention is a hollow particle. This composition may contain two or more types of second particles. The shape of the second particle may be spherical, needle-like (fibrous), or plate-like, preferably spherical. In this case, the dispersibility and processability of the composition are easily improved. Furthermore, this composition readily yields molded articles with excellent electrical properties.

[0026] The second spherical particle is preferably approximately true spherical. Approximately true spherical means that when observing particles using a scanning electron microscope (SEM), the proportion of particles with a minor axis to major axis ratio of 0.7 or higher is 95% or higher.

[0027] The second particle can be a resin particle or an inorganic particle, preferably an inorganic particle. In this case, the composition readily yields molded articles with excellent electrical properties, thermal conductivity, and low linear expansion. Examples of resins as particles include: cured products of heat-resistant thermoplastic resins and thermosetting resins. Specific examples of the aforementioned thermoplastic or cured resins include: polyester resins such as liquid crystal aromatic polyesters, polyimide resins, polyamide-imide resins, epoxy resins, maleimide resins, polyurethane resins, polyphenylene ether resins, polyphenylene oxide resins, and polyphenylene sulfide resins. Examples of inorganic particles include carbon, inorganic nitrides and inorganic oxides, with preferred examples being carbon fibers, glass, boron nitride, aluminum nitride, beryllium oxide, silicon dioxide, wollastonite, talc, cerium oxide, aluminum oxide, magnesium oxide, zinc oxide and titanium oxide.

[0028] The second particle is preferably a hollow glass particle and a hollow silicon dioxide particle, more preferably a hollow glass particle. In this case, a molded article with excellent electrical properties can be easily obtained from this composition. The hollow glass particles are preferably hollow borosilicate glass particles and hollow sodium-calcium borosilicate glass particles, and more preferably hollow sodium-calcium borosilicate glass particles. Specific examples of hollow silica particles include: the "E-SPHERES" series (manufactured by Pacific Cement Corporation), the "SiliNax" series (manufactured by Nippon Steel Mining Corporation), and the "Ecco sphere" series (manufactured by Emerson & Cuming Corporation). Specific examples of insulating glass particles include: the "S4630", "S3240-VS", "S60HS", "S32HS", "iM16K", and "iM30K" grades of the "Glass Bubbles" series (manufactured by 3M).

[0029] The D50 of the second particle is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 10 μm or more. The D50 of the second particle is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 20 μm or less. The true density of the second particle is preferably 0.2~1 g / cm3, more preferably 0.3~0.8 g / cm3. The bulk density of the second particle is preferably 0.1~0.5 g / cm3, more preferably 0.2~0.4 g / cm3. The compressive strength of the second particle is preferably 30 MPa or higher, more preferably 100 MPa or higher, and even more preferably 150 MPa or higher. The upper limit of the compressive strength is preferably 200 MPa. Furthermore, the compressive strength is measured by ASTM D 3102-78. Specifically, the compressive strength is defined as the pressure at which the hollow particles are broken down by 10% after adding an appropriate amount of hollow particles to glycerin and applying pressure.

[0030] The surface of the second particle is preferably treated with a silane coupling agent. Silane coupling agents can partially react and also form polysiloxane backbones. The hydrolyzable silane alkyl group in the silane coupling agent is preferably a monoalkoxysilane, dialkoxysilane, or trialkoxysilane, and more preferably a trialkoxysilane. The hydrolyzable silane alkyl group can be hydrolyzed. Examples of organic groups in silane coupling agents include: monovalent organic groups such as vinyl, epoxy, styrene, acryloxy, methacryloxy, amino, isocyanate, mercapto, benzotriazolyl, and acid anhydride; preferably monovalent organic groups such as vinyl, epoxy, benzotriazolyl, phenyl, or urea; and more preferably monovalent organic groups with an epoxy group. Silane coupling agents may have a plurality of different types of organic groups, or a plurality of the same type of organic groups.

[0031] The silane coupling agent is preferably a compound having a trialkoxysilyl group and a benzotriazolyl group or an epoxy group, and more preferably a compound having a trialkoxysilyl group and an epoxy group. Examples of silane coupling agents include: compounds with benzotriazolyl and trimethoxysilyl groups at the two ends of the main chain, compounds with three epoxy groups in the main chain and multiple triethoxysilyl groups in the side chain, compounds with a siloxane structure in the main chain and amino groups at both ends of the main chain, compounds with a butadiene structure in the main chain and one anhydride group and one trimethoxysilyl group in the side chain, and compounds with an alkoxysiloxane structure in the main chain and multiple epoxy groups in the side chain.

[0032] Examples of silane coupling agents include: vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-isocyanopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane. Alkane, p-styryltrimethoxysilane, 3-trimethoxysilylpropylsuccinic anhydride, N-2-(aminomethyl)-8-aminooctyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Specific examples of silane coupling agents include: "KBM-573", "KBM-403", "KBM-903", "KBE-903", "KBM-1403", "X-12-967C", "X-12-1214A", "X-12-984S", "X-12-1271A", "KBP-90", "KBM-6803", "X-12-1287A", "KBM-402", "KBE-402", "KBE-403", "KR-516", "KBM-303", "KBM-4803", "KBM-3063", and "KBM-13" (all manufactured by Shin-Etsu Chemical Industry Co., Ltd.).

[0033] One method for surface-treating the second particle using a silane coupling agent is to mix the second particle with a solution containing the silane coupling agent and then dry it. During the mixing process, the mixture of the solution and the second particle can be heated or water can be added to promote the reaction of the silane coupling agent. Alternatively, a reaction catalyst can be used to accelerate the reaction of the silane coupling agent. Furthermore, after drying, the second particle, which has been surface-treated with the silane coupling agent, can be broken down or graded.

[0034] The second particle, which is a hollow silicon dioxide particle or a hollow glass particle, is preferably cleaned by immersion in an alkaline solution or by washing with the aforementioned alkaline solution to reduce the sodium content on its surface. An example of an alkaline solution is an aqueous solution of ammonium hydroxide. The sodium oxide content on the surface of the second particle, which is a hollow silicon dioxide particle or hollow glass particle, is preferably 1-4% by mass. Furthermore, this content is obtained by XPS (x-ray photoelectron spectroscopy) surface analysis. In this case, the second particle easily interacts with the first or third particle, resulting in excellent dispersibility and processability of the composition. Moreover, this composition readily yields molded articles with excellent electrical properties and particularly low dielectric loss tangent. The second particle, which is a hollow silicon dioxide particle or hollow glass particle, is preferably immersed in an alkaline solution or washed and then surface-treated with a silane coupling agent. In this case, the second particle can easily interact with the first or third particle.

[0035] The second particle is preferably treated at high temperature to remove water. In this case, the water content of the molded article formed from this composition can be reduced, and a molded article with excellent electrical properties can be easily obtained. The optimal temperature for high-temperature treatment is 500~1000℃.

[0036] The third particle in this invention is an inorganic particle with an aspect ratio greater than 1, and is a non-hollow particle. This composition may contain two or more types of third particles. The third particle can be spherical, needle-like (fibrous), or plate-like in shape. Specifically, it can be spherical, scaly, layered, leaf-like, almond-like, columnar, cockscomb-like, equiaxed, leaf-like, mica-like, blocky, flat, wedge-shaped, rose-like, net-like, or prismatic, with scaly being preferred. In this case, the third particle easily forms a thermally conductive channel in the molded article formed from this composition, resulting in excellent thermal conductivity and low linear expansion of the molded article.

[0037] The aspect ratio of the third particle is greater than 1, preferably greater than 2, and even more preferably greater than 5. The aspect ratio is preferably less than 10,000. As for the inorganic material in the third particle, examples can be the same as those in the second particle mentioned above. Specifically, examples include: boron nitride, silicon nitride, aluminum nitride, silicon dioxide, zinc oxide, titanium oxide, talc, block talc, etc. Among these, the third particle is preferably boron nitride particles, silicon nitride particles, and aluminum nitride particles, more preferably boron nitride particles, and even more preferably hexagonal boron nitride. It is believed that when the third particle is a flake-shaped boron nitride particle, a lamellar structure is easily formed in the composition and the molded article formed from the composition, thus creating a heat conduction channel. As a result, the composition exhibits excellent dispersibility, and the molded article also has excellent thermal conductivity and low linear expansion, making it superior.

[0038] The D50 of the third particle is preferably 1 μm or more, more preferably 5 μm or more. The D50 of the third particle is preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less.

[0039] This composition may contain third particles from two or more third particle powders with different D50 values. In this case, the composition preferably contains coarse particles from third particle powders with a D50 of 10-50 μm and fine particles from third particle powders with a D50 of 0.5-4 μm. By including coarse and fine particles as third particles in this composition, fine particles can be filled between the coarse particles, thereby increasing the filling rate of the third particles in the molded article formed from this composition. When this composition contains coarse and fine particles as third particles, the proportion of coarse particles relative to the total amount of third particles is preferably 70% or more, and more preferably 75% or more. If the proportion of coarse particles is within this range, the third particles in the molded article tend to be densely filled.

[0040] The surface of the third particle is preferably treated with a silane coupling agent. Examples of silane coupling agents that are the same as those used for the surface treatment of the second particle can be cited, and their suitable range and treatment methods are also the same.

[0041] Specific examples of silicon dioxide particles include the "Admafine" series (manufactured by Admatechs) and the "SFP" series (manufactured by Denka). As a specific example of zinc oxide particles, the "FINEX" series (manufactured by Sakai Chemical Co., Ltd.) can be cited. Specific examples of titanium dioxide particles include the "Tipaque" series (manufactured by Ishihara Sangyo Co., Ltd.) and the "JMT" series (manufactured by Teikoku Co., Ltd.). As a specific example of talc particles, one can cite the "SG" series (manufactured by NIPPON TALC). As a specific example of block talc particles, one can cite the "BST" series (manufactured by NIPPON TALC). Specific examples of boron nitride particles include: the "UHP" series (manufactured by Showa Denko Corporation), and the "GP" and "HGP" grades of the "Denka Boron Nitride" series (manufactured by Denka Corporation). 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 nitride fillers include: the "High Purity Aluminum Nitride" series (Tokuyama Corporation) and the "TOYAL TecFiller TFZ" series (manufactured by Toyo Aluminium Corporation).

[0042] The D50 of the first particle is preferably smaller than either the D50 of the second particle or the D50 of the third particle. The ratio of the D50 of the first particle to the D50 of the second particle is preferably 0.8 or less, more preferably 0.5 or less. The above ratio is preferably 0.05 or more, more preferably 0.1 or more. The ratio of the D50 of the first particle to the D50 of the third particle is preferably 0.8 or less, more preferably 0.5 or less. The ratio is preferably 0.1 or more, more preferably 0.2 or more. The average particle size of the second particle relative to the D50 of the third particle is preferably 3 or less, more preferably 2.5 or less. The above ratio is preferably 0.5 or more, more preferably 1 or more, and even more preferably 1.5 or more.

[0043] Relative to the total volume of the first, second, and third particles in the composition, the volume concentration of the first particle is preferably 40% or more, more preferably 50% or more. The volume concentration of the first particle is preferably 70% or less. Relative to the total volume of the first, second, and third particles in the composition, the volume concentration of the second particle is preferably 20% or more, more preferably 30% or more. The volume concentration of the second particle is preferably 50% or less, more preferably 40% or less. Relative to the total volume of the first, second, and third particles in the composition, the volume concentration of the third particle is preferably 5% or more, more preferably 10% or more. The volume concentration of the third particle is preferably less than 30%, more preferably less than 20%. Relative to the total volume of the first, second, and third particles in the composition, the volume concentrations of the first, second, and third particles are preferably 40-70%, 20-50%, and 5% or more but less than 30%, respectively.

[0044] The volume concentration ratio of the first particle to the volume concentration of the second particle in this composition is greater than 1, preferably 1.2 or more. The ratio is preferably 5 or less, and more preferably 3 or less. The volume concentration of the third particle relative to the volume concentration of the first particle in this composition is preferably 0.5 or less, more preferably 0.4 or less. The above ratio is preferably 0.05 or more, more preferably 0.1 or more. The volume concentration ratio of the third particle to the volume concentration of the second particle in this composition is less than 0.6, preferably less than 0.5. More preferably, the ratio is 0.1 or higher, and even more preferably 0.3 or higher. When the volume concentration or volume concentration ratio is within this range, the above-described mechanism facilitates excellent dispersibility of the composition. Furthermore, this composition readily yields molded articles with low coefficients of linear expansion, dielectric constants, and dielectric loss tangents, as well as excellent thermal conductivity and adhesion.

[0045] This composition may further include a resin different from polymer F. This other resin may be included in the composition in the form of non-hollow particles, or, when the composition includes a liquid dispersion medium, may be dissolved or dispersed in the liquid dispersion medium. Other examples of resins include thermoplastic resins and thermosetting resins, which are hardening resins. Specific examples of the aforementioned thermoplastic or hardening resins include polyester resins such as liquid crystal aromatic polyesters, amide resins, epoxy resins, maleimide resins, polyurethane resins, polyphenylene ether resins, polyphenylene oxide resins, and polyphenylene sulfide resins. Other resins are preferably aromatic polymers, and more preferably at least one aromatic amide polymer selected from the group consisting of aromatic polyimides, aromatic polyamides, aromatic polyamides, and precursors of aromatic polyamides. The aromatic polymer is preferably contained in the composition in the form of a varnish dissolved in a liquid dispersion medium. Specific examples of aromatic amide polymers include: the "UPIA-AT" series (manufactured by Ube Industries, Inc.); the "Neopulim" series (manufactured by Mitsubishi Gas Chemical Co., Ltd.); the "SPIXAREA" series (manufactured by SOMAR Corporation); the "Q-PILON" series (manufactured by PI Technology Research Institute); the "WINGO" series (manufactured by Wingo Technology Co., Ltd.); the "TOHMIDE" series (manufactured by T&K TOKA Co., Ltd.); the "KPI-MX" series (manufactured by Kawamura Industries Co., Ltd.); and "HPC-1000" and "HPC-2100D" (both manufactured by Showa Denko Materials Co., Ltd.).

[0046] In this composition containing other resins, the volume concentration of the other resins relative to the total volume of the first particle, the second particle, and the third particle is preferably 0.1% by volume or more, more preferably 1% by volume or more. The aforementioned volume concentration is preferably 15% by volume or less, more preferably 10% by volume or less.

[0047] This composition may be in powder form or may further contain a liquid dispersion medium to be in liquid form. The liquid dispersion medium is a compound that is liquid at atmospheric pressure and 25°C, preferably a compound with a boiling point of 50-240°C. This composition may contain two or more liquid dispersion media. When two liquid dispersion media are contained, the two liquid dispersion media are preferably miscible. The liquid dispersion medium is preferably a compound selected from the group consisting of water, amides, ketones and esters. Examples of amides include: N-methyl-2-pyrrolidone, N,N-dimethylmethoxymethylamine, N,N-dimethylacetamide, N,N-dimethylpropionic acid, 3-methoxy-N,N-dimethylpropionic acid, 3-butoxy-N,N-dimethylpropionic acid, N,N-diethylmethoxymethylamine, hexamethylphosphatidyltriamine, and 1,3-dimethyl-2-imidazolidinedone. 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, and γ-valerolactone.

[0048] When the composition contains a liquid dispersion medium, the content of the liquid dispersion medium is preferably 40% by volume or more, more preferably 60% by volume or more. The content of the liquid dispersion medium is preferably 90% by volume or less, more preferably 80% by volume or less. When the composition contains a liquid dispersion medium, the concentration of solids in the composition is preferably 20% by volume or more, more preferably 40% by volume or more. The concentration of solids is preferably 80% by volume or less, more preferably 70% by volume or less. Furthermore, solids refer to the total amount of substances forming solids in the molded article formed from the composition. Specifically, the first particle, the second particle, and the third particle are solids; when the composition contains other resins, the other resins are also solids, and the total volume concentration of these components is the concentration of solids in the composition.

[0049] When the composition contains a liquid dispersion medium, from the viewpoint of improving the dispersion stability of the first particle, the second particle and the third particle, the composition preferably further contains a nonionic surfactant. Nonionic surfactants are preferably glycol-based, acetylene-based, silicone-based, and fluorine-based surfactants, with silicone-based surfactants being more preferred. Two or more nonionic surfactants may be used. When two nonionic surfactants are used, silicone-based and glycol-based surfactants are preferred. 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); the "Unidyne" series (manufactured by Daikin Industries); "BYK-347", "BYK-349", "BYK-378", "BYK-3450", "BYK-3451", "BYK-3455", and "BYK-3456" (manufactured by BYK-Chemie Japan); "KF-6011" and "KF-6043" (manufactured by Shin-Etsu Chemical Co., Ltd.); and the "Tergitol" series (manufactured by Dow Chemical Company, such as "Tergitol TMN-100X"). When the composition contains a nonionic surfactant, the content of the nonionic surfactant in the composition is preferably 1 to 15% by volume.

[0050] The composition preferably further comprises a silane coupling agent. In this case, the bonding force of the first, second, and third particles is enhanced, and the composition easily forms a molded article in which particle shedding is suppressed. As a silane coupling agent, examples can be given of silane coupling agents that are the same as those used for the surface treatment of the second particle, and their suitable range is also the same. When the composition contains a silane coupling agent, the content of the silane coupling agent in the composition is preferably 1 to 10 volumes.

[0051] This composition may further contain various fillers and additives, such as thixotropic agents, viscosity modifiers, defoamers, dehydrating agents, plasticizers, weathering agents, antioxidants, heat stabilizers, lubricants, antistatic agents, whitening agents, colorants, conductive agents, release agents, surface treatment agents, flame retardants, and conductive fillers.

[0052] When the 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 composition is preferably 10000 mPa·s or less, more preferably 3000 mPa·s or less. When the composition contains a liquid dispersion medium and is in a liquid state, its thixotropic ratio is preferably 1.0 to 3.0. When this composition contains water as a liquid dispersion medium, its pH value is preferably 8-10 from the viewpoint of improving long-term shelf life. The pH value of this composition can be adjusted by pH adjusters (amines, ammonia, citric acid, etc.) or pH buffers (tris(hydroxymethyl)aminomethane, ethylenediaminetetraacetic acid, ammonium bicarbonate, ammonium carbonate, ammonium acetate, etc.).

[0053] This composition is obtained by mixing the first particle, the second particle and the third particle, and other resins, liquid dispersion media, surfactants, silane coupling agents, additives, etc., as needed. This composition can be obtained by mixing the first particle together with the second and third particles, or by mixing them separately and sequentially. Alternatively, a masterbatch of these particles can be prepared in advance and mixed with the remaining components. There are no particular restrictions on the order of mixing, and the mixing method can involve mixing all at once or mixing in multiple stages. Examples of mixing devices for obtaining this composition include: Henschel mixers, pressure kneaders, Bamboo mixers, and planetary mixers with blades; ball mills, grinding mills, basket mills, sand mills, sand grinders, DYNO-MILL, Dispermat, SC-MILL, Spike Mills, and stirred mills with media pulverizing devices; and micro-spray homogenizers, nanomers, ULTIMAIZERs, ultrasonic homogenizers, high-speed dispersers, dispersers, high-speed impellers, thin-film rotary high-speed mixers, self-rotating and revolution-rotating mixers, and V-type mixers with other dispersing mechanisms.

[0054] A suitable method for manufacturing this composition containing a liquid dispersion medium is exemplified by the following method: The first particle is pre-mixed with a portion of the liquid dispersion medium to obtain a mixture, and then the mixture is added to the remaining liquid dispersion medium to obtain the composition. The liquid dispersion medium used in mixing and adding can be the same type of liquid dispersion medium or different types of liquid dispersion media. The second particle, the third particle, or different resins, surfactants, silane coupling agents, and additives can be mixed during mixing or when the mixture is added to the liquid dispersion medium.

[0055] The mixture obtained by mixing can be in the form of a paste (a paste with a viscosity of 1,000 to 100,000 mPa·s, etc.) or a wet powder (a wet powder with a viscosity of 10,000 to 100,000 Pa·s, etc., as measured by Capillograph). Furthermore, the viscosity measured by the Capillograph was obtained using a capillary with a length of 10 mm and a radius of 1 mm, with the furnace diameter set to 9.55 mm, the load cell capacity set to 2 t, the temperature set to 25℃, and the shear rate set to 1 s⁻¹.

[0056] The mixing process is best carried out using a planetary mixer. A planetary mixer is a mixing device with two rotating and revolving agitators. The mixing during addition is preferably carried out using a thin-film rotary high-speed mixer. The thin-film rotary high-speed mixer is a stirring device that uses the inner wall of a cylindrical stirring tank to spread the first particle and liquid dispersion medium into a thin film and rotate it, while applying centrifugal force to mix them.

[0057] Through the above-described mechanism of action, this composition readily yields molded articles with a dielectric constant of 2.8 or less and a dielectric loss tangent of 0.0025 or less. Preferably, the dielectric constant of the molded article is 2.4 or less, more preferably 2.0 or less. Furthermore, the dielectric constant is preferably greater than 1.0. Preferably, the dielectric loss tangent of the molded article is 0.0022 or less, more preferably 0.0020 or less. Furthermore, the dielectric loss tangent is preferably greater than 0.0010.

[0058] If this composition is used in molding methods such as extrusion, molded articles such as sheets can be obtained. When the composition contains a liquid dispersion medium and is in a liquid state, it is preferable to extrude the composition into a sheet. The extruded sheet can then be subjected to compression molding, calendering, or other processes to produce a cast sheet. Preferably, the sheet is then heated to remove the liquid dispersion medium and to calcine the F polymer. When the composition is in powder form, it is preferable to melt extrude the composition. Extrusion molding can be performed using a single-screw extruder, a multi-screw extruder, or the like. Alternatively, this composition can be injection molded to obtain a molded article. When forming a molded article, the composition can be directly melt-extruded or injection-molded, or the composition can be melt-kneaded to form granules, and the granules can be melt-extruded or injection-molded to obtain sheets or other molded articles.

[0059] The sheet obtained from this composition preferably has a thickness of 25 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more. The sheet thickness is preferably 200 μm or less. The suitable ranges for the dielectric constant and dielectric loss tangent of the sheet are the same as those for the dielectric constant and dielectric loss tangent of the above-mentioned molded material. The coefficient of linear expansion of the sheet material is preferably below 100 ppm / ℃, more preferably below 80 ppm / ℃. The lower limit of the coefficient of linear expansion of the sheet material is 30 ppm / ℃. Furthermore, the coefficient of linear expansion refers to the value obtained by measuring the coefficient of linear expansion of a test piece in the range of 25℃ to 260℃ according to the test method specified in JIS C 6471:1995. The in-plane thermal conductivity of the sheet material is preferably 1.0 W / m·K or higher, and more preferably 3.0 W / m·K or higher. The upper limit for the thermal conductivity of the sheet material is 20 W / m·K.

[0060] If the sheet is laminated onto a substrate, a laminate can be formed. Examples of methods for manufacturing the laminate include: using a co-extruder as the extruder to extrude the raw material of the substrate and the composition together; extruding the composition onto the substrate; and hot-pressing the sheet to the substrate. Examples of substrates include: metal substrates (copper, nickel, aluminum, titanium, and alloys thereof, etc.), heat-resistant resin films (polyimide, polyamide, polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamideimide, liquid crystal polyester, tetrafluoroethylene polymers, etc.), prepreg substrates (precursors to fiber-reinforced resin substrates), ceramic substrates (silicon carbide, aluminum nitride, silicon nitride, etc.), and glass substrates.

[0061] Examples of substrate shapes include: planar, curved, and uneven. Furthermore, substrate shapes can be any of the following: foil, plate, film, or fibrous. The preferred surface roughness of the substrate is 0.01~0.05 μm. The surface of the substrate can be surface-treated with a silane coupling agent or subjected to plasma treatment. The preferred silane coupling agent is a functionalized silane coupling agent such as 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, or 3-isocyanopropyltriethoxysilane. The peel strength between the sheet and the substrate is preferably 10 N / cm or more, and more preferably 15 N / cm or more. The peel strength is preferably 100 N / cm or less.

[0062] If this composition is disposed on the surface of a substrate to form a polymer layer comprising polymer F, a second particle, and a third particle, a laminate having a substrate layer comprising the substrate and a polymer layer can be obtained. The polymer layer is preferably formed by placing the composition containing a liquid dispersion medium on the surface of a substrate, heating to remove the dispersion medium, and then heating to calcine the F polymer. As a substrate, examples and substrates similar to those used in the above-mentioned sheet laminations can be cited, and their suitable forms are also the same.

[0063] Examples of methods for preparing this composition include: coating, droplet spraying, and dipping, with roller coating, blade coating, bar coating, die coating, or spraying being preferred. The heating for removing the liquid dispersion medium is preferably performed at 100-200°C for 0.1-30 minutes. During this heating, the liquid dispersion medium does not need to be completely removed; it is sufficient to remove it to the point where the layer formed by the filling of the first, second, and third particles can maintain a self-supporting film. Furthermore, air can be blown during heating to promote the removal of the liquid dispersion medium through air drying. The heating during the calcination of polymer F is preferably carried out at a temperature above the calcination temperature of polymer F, and more preferably at 360~400°C for 0.1~30 minutes. Examples of heating devices used in various heating processes include ovens and ventilated drying furnaces. The heat source in these devices can be a contact heat source (hot air, hot plate, etc.) or a non-contact heat source (infrared rays, etc.). Furthermore, each heating can be carried out under normal pressure or under reduced pressure. Furthermore, the gas atmosphere used in each heating process can be either an air atmosphere or an inert gas atmosphere (helium, neon, argon, nitrogen, etc.).

[0064] The polymer layer is formed through the steps of preparing and heating the composition. These steps may be performed once or repeatedly more than twice. For example, the composition may be prepared on the surface of a substrate, heated to form a polymer layer, and then the composition may be prepared on the surface of the polymer layer and heated to form a second polymer layer. Alternatively, the composition may be prepared on the surface of a substrate and heated to remove the liquid dispersion medium, and then the composition may be prepared on the surface of the substrate and heated to form a polymer layer. This composition can be disposed on only one surface of the substrate, or on both sides of the substrate. In the former case, a laminate having a substrate layer and a polymer layer disposed on one surface of the substrate layer can be obtained; in the latter case, a laminate having a substrate layer and polymer layers disposed on both surfaces of the substrate layer can be obtained.

[0065] Suitable examples of laminates include: metal foil laminates having a metal foil and a polymer layer disposed on at least one surface of the metal foil, and multilayer films having a polyimide film and polymer layers disposed on two surfaces of the polyimide film. The suitable ranges for the thickness, dielectric constant, dielectric loss tangent, coefficient of linear expansion, in-plane thermal conductivity, and peel strength between the polymer layer and the substrate layer are the same as those for the sheet obtained from this composition.

[0066] This composition can be used to impart insulation, heat resistance, corrosion resistance, chemical resistance, water resistance, impact resistance, and thermal conductivity to materials. Specifically, this composition can be used in: printed wiring boards, thermal interface materials, power module substrates, coils for motors and other power devices, vehicle engines, heat exchangers, vials, syringes, ampoules, medical wiring, secondary batteries such as lithium-ion batteries, primary batteries such as lithium batteries, free radical batteries, solar cells, fuel cells, lithium-ion capacitors, hybrid capacitors, capacitors, capacitors (aluminum electrolytic capacitors, tantalum electrolytic capacitors, etc.), electrochromic elements, electrochemical switching elements, electrode adhesives, electrode separators, and electrodes (positive and negative electrodes). Furthermore, this composition can also be used as an adhesive for bonding parts. Specifically, this composition can be used to bond ceramic parts, bond metal parts, bond IC (integrated circuit) chips or electronic components such as resistors and capacitors in the substrate of semiconductor elements or module parts, bond circuit boards to heat sinks, and bond LED (light emitting diode) chips to substrates. Furthermore, this composition, which includes conductive fillers, is also suitable for applications requiring conductivity, such as in the field of printed electronics. Specifically, it can be used to manufacture conductive components in printed circuit boards, sensor electrodes, etc.

[0067] The molded articles, sheets and laminates formed from this composition can be used as antenna parts, printed circuit boards, aircraft parts, automotive parts, sporting goods, food industry supplies, heat dissipation parts, coatings, cosmetics, etc. Specifically, it can be used as: wire sheathing materials (aircraft wires, etc.), enameled wire sheathing materials for motors in electric vehicles, electrical insulating tapes, insulating tapes for oil excavation, oil transport hoses, hydrogen tanks, materials for printed circuit boards, separation membranes (microfiltration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, gas separation membranes, etc.), electrode adhesives (for lithium secondary batteries, fuel cells, etc.), replication rollers, covers for furniture, automotive dashboards, and household appliances, sliding components (load bearings, yaw bearings, sliding shafts, valves, bearings, bushings, seals, thrust washers, wear-resistant parts). Pistons, toggle switches, gears, cams, belt conveyors, food conveyor belts, tension ropes, wear-resistant pads, wear-resistant strips, tubular lights, test sockets, wafer conductors, wear parts for centrifugal pumps, chemical and water supply pumps, tools (shovels, files, cones, saws, etc.), boilers, hoppers, pipes, ovens, baking molds, chutes, stringing for rackets, molds, toilets, container covering materials, heat dissipation base plates for power devices, heat dissipation components for wireless communication devices, transistors, thyristors, rectifiers, transformers, power MOSFETs (metal-oxide-semiconductor field-effect transistors), CPUs (central processing units), heat sinks, metal heat sinks, blades for windmills or wind power generation equipment or aircraft, housings for computers or monitors, electronic device materials, interior and exterior components for automobiles, sealing materials for processing machines or vacuum ovens that undergo heat treatment under low oxygen conditions, plasma treatment equipment, heat dissipation components within processing units of sputtering or various dry etching equipment, and electromagnetic wave shielding. The molded articles, sheets and laminates formed from this composition can be used as electronic substrate materials such as flexible printed wiring boards and rigid printed wiring boards; protective films or heat dissipation substrates, especially heat dissipation substrates for automobiles. When using molded articles, sheets, and laminates formed from this composition as heat dissipation components, they can be directly bonded to a substrate to which the molded article, sheet, or laminate is the target, or they can be bonded to the substrate to which the target is the substrate through an adhesive layer such as a silicone adhesive layer. Example

[0068] The present invention will now be described in detail with reference to embodiments, but the present invention is not limited thereto. 1. Preparation of each ingredient [Particle 1] Particle 1: A tetrafluoroethylene polymer (melting temperature: 300℃) containing 97.9 mol% TFE units, 0.1 mol% NAH units, and 2.0 mol% PPVE units, with 1000 carbonyl groups per 1×10⁶ carbon atoms in the main chain (D50: 2.1 μm, non-hollow). Particle 2: Non-thermal-melting polytetrafluoroethylene particles (D50: 0.3 μm, non-hollow) Particle 3: Particles of a tetrafluoroethylene polymer (melting temperature: 305℃) containing 98.7 mol% TFE units and 1.3 mol% PPVE units, and without oxygen-containing polar groups (D50: 1.8 μm, non-hollow). [Particle 2] Particle 4: Sodium calcium borosilicate glass particles (D50: 16 μm, compressive strength: 180 MPa, spherical and substantially true spherical and hollow) surface-treated with vinyltrimethoxysilane. [Third Particle] Particle 5: Boron nitride particles (D50: 7 μm, flaky and non-hollow, aspect ratio: 5 or higher) that have been surface-treated with an epoxy-containing silane coupling agent. [Liquid Dispersion Medium] NMP: N-methyl-2-pyrrolidone [Other Resins] Varnish 1: NMP varnish of thermoplastic aromatic polyimide (PI1)

[0069] 2. Example of manufacturing the composition [Example 1] Varnish 1 and NMP are added to a crucible and mixed. Then, a mixture of powders consisting of particles 1, 4, and 5 is added to the crucible and mixed to prepare a compound. This compound is then kneaded in a planetary mixer and removed to obtain a mixed powder 1 containing particles 1, 4, 5, PI1, and NMP in a volume ratio of 50:33:17:5:30. Mixed powder 1 is in a wet powder state. NMP was added to the mixed powder 1 in several portions while simultaneously defoaming and stirring using a planetary mixer at 2000 rpm. Then, NMP was added in several portions and stirred to prepare a liquid composition, resulting in composition 1 containing particles 1, 4, 5, PI1, and NMP in a volume ratio of 50:33:17:5:110. The viscosity of composition 1 was 400 mPa·s. [Example 2] By changing particle 1 to particles 1 and 2, composition 2, comprising particles 1, 2, 4, 5, PI1, and NMP in a volume ratio of 20:30:33:17:5:110, was obtained in the same manner as in Example 1. The viscosity of composition 1 was 500 mPa·s.

[0070] [Example 3] Particle 1 was replaced with particle 3. Otherwise, composition 3 was obtained in the same manner as in Example 1, comprising particles 3, 4, 5, PI1, and NMP in a volume ratio of 50:33:17:5:110 in sequence. The viscosity of composition 3 was 500 mPa·s. [Example 4] Particle 1 was changed to particle 3, and the amount of particle 4 was further changed. Otherwise, composition 4, which contains particles 3, 4, 5, PI1 and NMP in a volume ratio of 50:50:17:5:110, was obtained in the same manner as in Example 1. The viscosity of composition 4 is 900 mPa·s. [Example 5] Particle 1 was changed to particle 3, and the amount of particle 4 was further changed. Otherwise, composition 5, containing particles 3, 4, 5, PI1, and NMP in a volume ratio of 50:25:17:5:110, was obtained in the same manner as in Example 1. The viscosity of composition 5 was 300 mPa·s. The particle ratios, volume concentrations of each particle, and solid content concentrations in each composition are summarized in Table 1.

[0071] [Table 1] Composition Number 1 2 3 4 5 Compared to A, ※ 1[vol% / vol%] 1.5 1.5 1.5 1.0 2.0 Compared to B, ※ 2[vol% / vol%] 0.5 0.5 0.5 0.3 0.7 Concentration 1※ 3 [vol%] 50 50 50 43 54 Second concentration※ 4 [vol%] 33 33 33 43 27 Concentration 3※ 5 [vol%] 17 17 17 14 19 Solid content concentration [vol%] 49 49 49 53 59 ※1: "Ratio A" indicates the ratio of the volume concentration of the first particle to the volume concentration of the second particle. ※2: "B" indicates the ratio of the volume concentration of the third particle to the volume concentration of the second particle. ※3: "First concentration" refers to the volume concentration of the first particle out of the total volume of the first to third particles. ※4: "Second concentration" refers to the volume concentration of the second particle in the total volume of the first to third particles. ※5: "Third concentration" refers to the volume concentration of the third particle out of the total volume of the first to third particles.

[0072] 3. Manufacturing of laminated bodies Using a bar coater, composition 1 is coated onto the surface of a strip of copper foil with a thickness of 18 μm to form a wet film. Next, the copper foil with the wet film is dried in a drying oven at 110°C for 5 minutes to form a dry film. Subsequently, the copper foil with the dry film is heated in a nitrogen oven at 380°C for 3 minutes. This produces a laminate 1 having a copper foil and a polymer layer disposed on the surface of the copper foil, the polymer layer comprising molten calcined particles 1, particles 4, particles 5, and PI1, with a thickness of 100 μm. Laminates 2 to 5 are manufactured from compositions 2 to 5 in the same manner as laminate 1.

[0073] 4. Evaluation 4-1. Evaluation of the dispersibility and stability of the composition After storing each composition in a container at 25°C, its dispersibility was visually confirmed, and its dispersion stability was evaluated according to the following criteria. [Evaluation Criteria] ○: No aggregates were detected. △: Aggregates can also be observed at the bottom of the container. If shear force is applied and the mixture is stirred, it will redisperse evenly. ×: Aggregates were also observed at the bottom of the container. Even with shear force and stirring, they were difficult to disperse again.

[0074] 4-2. Evaluation of the peel strength of laminates Rectangular specimens (100 mm long and 10 mm wide) are cut from each laminate. Then, the specimen is fixed at a position 50 mm from one end along the length direction, and the copper foil and polymer layer are peeled off at a 90° angle relative to the specimen from one end along the length direction at a stretching speed of 50 mm / min. Then, the maximum load applied at this time is set as the peel strength (N / cm), and the measurement is performed and evaluated according to the following criteria. [Evaluation Criteria] ○: 15 N / cm or higher △: 10 N / cm or higher but less than 15 N / cm ×: Not reaching 10 N / cm

[0075] 4-3. Evaluation of the linear expansion coefficient of laminated bodies For each laminate, the copper foil of the laminate was removed by etching with an aqueous ferric chloride solution to prepare a sheet as a separate polymer layer. Square specimens of 180 mm were cut from the prepared sheets, and the coefficient of linear expansion (ppm / °C) of the specimens was measured in the range of 25°C to 260°C according to the test method specified in JIS C 6471:1995. The specimens were evaluated according to the following criteria. [Evaluation Criteria] ○: Below 80 ppm / ℃ △: Exceeding 80 ppm / ℃ but below 100 ppm / ℃ ×: Exceeding 100 ppm / ℃

[0076] 4-4. Evaluation of the electrical properties of laminates A 5 cm × 10 cm square test piece was cut from the center of each sheet obtained in the same manner as in 4-3. The dielectric constant and dielectric loss tangent of the sheet were measured by SPDR (split post dielectric resonator) method (measurement frequency: 10 GHz), and evaluated according to the following criteria. [Evaluation Criteria for Dielectric Constant] ○: Below 2.4 △: Above 2.4 and below 2.8 ×: Exceeds 2.8 [Evaluation Criteria for Dielectric Loss Tangent] ○: 0.0020 or less △: More than 0.0020 and less than 0.0025 ×: Exceeds 0.0025

[0077] 4-5. Evaluation of the thermal conductivity of laminated bodies A 10 mm × 10 mm square test piece was cut from the center of each sheet obtained in the same manner as in 4-3, and its in-plane thermal conductivity (W / m·K) was measured and evaluated according to the following criteria. [Evaluation Criteria] ○: 3 W / m·K or higher △: 1 W / m·K or higher but less than 13 W / m·K ×: Not reaching 1 W / m·K The results are summarized in Table 2.

[0078] [Table 2] Composition or laminate number 1 2 3 4 5 Dispersion stability ○ ○ △ × △ Peel strength ○ ○ △ × △ coefficient of linear expansion ○ ○ △ × × Dielectric constant ○ ○ △ △ × Dielectric loss tangent △ ○ △ △ × thermal conductivity ○ ○ △ × × [Industrial Applicability]

[0079] Based on the above results, it can be seen that the composition has excellent dispersion stability. The laminate formed by the composition highly exhibits the physical properties of polymer F, the second particle and the third particle, with excellent peel strength, low linear expansion, electrical properties and thermal conductivity. Furthermore, the entire contents of the specification, scope of application and abstract of Japanese Patent Application No. 2021-109686, filed on June 30, 2021, are incorporated herein as disclosure of the present invention.

Claims

1. A composition comprising: a first particle of a tetrafluoroethylene-based polymer, a second hollow particle, and a third particle of an inorganic compound having an aspect ratio greater than 1, wherein the volume concentration of the first particle is greater than 1 relative to the volume concentration of the second particle, and the volume concentration of the third particle is less than 0.6 relative to the volume concentration of the second particle, wherein the second particle is a hollow silicon dioxide particle or a hollow glass particle, and the third particle is a boron nitride particle, a silicon nitride particle, or an aluminum nitride particle.

2. The composition of claim 1, wherein, relative to the total volume of the first particle, the second particle, and the third particle, the volume concentration of the first particle, the second particle, and the third particle are respectively 40-70%, 20-50%, and 5% or more but less than 30%.

3. The composition of claim 1 or 2, wherein the first particle is a particle of a thermomeltable tetrafluoroethylene polymer, and the thermomeltable tetrafluoroethylene polymer is a thermomeltable tetrafluoroethylene polymer having an oxygen-containing polar group and a melting temperature of 200 to 320°C.

4. The composition of claim 1 or 2, comprising particles of a heat-melting tetrafluoroethylene polymer and particles of a non-heat-melting tetrafluoroethylene polymer as the first particle mentioned above.

5. The composition of claim 1 or 2, wherein the average particle size of the first particle is 0.01 μm or more but less than 10 μm.

6. The composition of claim 1 or 2, wherein the average particle size of the second particle is 1 to 100 μm.

7. The composition of claim 1 or 2, wherein the average particle size of the third particle is 1 to 50 μm.

8. The composition of claim 1 or 2, wherein the third particle is a particle that has been surface-treated with a silane coupling agent.

9. The composition of claim 1 or 2, wherein the average particle size of the first particle is smaller than either the average particle size of the second particle or the average particle size of the third particle.

10. The composition of claim 1 or 2, wherein the ratio of the average particle size of the second particle to the average particle size of the third particle is 0.5 to 3.

11. The composition of claim 1 or 2, used to obtain a molded article having a dielectric constant of 2.8 or less and a dielectric loss tangent of 0.0025 or less.

12. A method for manufacturing a sheet, wherein a composition of any one of claims 1 to 11 is extruded to obtain a sheet comprising the aforementioned tetrafluoroethylene polymer, the aforementioned second particle, and the aforementioned third particle.

13. A method for manufacturing a laminate, wherein a composition of any one of claims 1 to 11 is disposed on the surface of a substrate to form a polymer layer comprising the aforementioned tetrafluoroethylene polymer, the aforementioned second particle and the aforementioned third particle, thereby obtaining a laminate having a substrate layer comprising the aforementioned substrate and the aforementioned polymer layer.