WO2023163025A1

WO2023163025A1 - Composition

Info

Publication number: WO2023163025A1
Application number: PCT/JP2023/006416
Authority: WO
Inventors: 敦美光永
Original assignee: Ａｇｃ株式会社
Priority date: 2022-02-28
Filing date: 2023-02-22
Publication date: 2023-08-31
Also published as: TW202344599A

Abstract

The present invention provides a composition that contains, in prescribed ranges, tetrafluoroethylene-based polymer particles and spheroidal and non-spheroidal boron nitride particles having a prescribed average particle diameter, that has excellent dispersibility, and that makes it possible to form a molded article which has low linear expansion coefficient, low dielectric constant, and low dielectric loss tangent, and which has excellent thermal conductivity, excellent bending tolerance, and excellent adhesiveness.　Provided is a composition comprising: tetrafluoroethylene-based polymer particles; spheroidal boron nitride particles that have an average particle diameter of 5-40 μm; and non-spheroidal boron nitride particles that have an average particle diameter of less than 15 μm, wherein the mass ratio of the non-spheroidal boron nitride particles with respect to the total mass of the spheroidal boron nitride particles and the non-spheroidal boron nitride particles is less than 30%.

Description

Composition

The present invention relates to a predetermined composition containing particles of a tetrafluoroethylene-based polymer, spherical boron nitride particles, and non-spherical boron nitride particles.

In recent years, in order to respond to the high speed and high frequency of mobile communication devices such as mobile phones, materials with high thermal conductivity, low coefficient of linear expansion, low dielectric constant and low dielectric loss tangent are required for printed circuit boards of communication devices. A tetrafluoroethylene-based polymer, which has a low dielectric constant and a low dielectric loss tangent, has attracted attention.
Compositions of tetrafluoroethylene-based polymers and other components have been studied in order to obtain materials with better physical properties. Patent Document 1 proposes a powder composition of tetrafluoroethylene-based polymer particles and two types of boron nitride particles having different particle sizes.

JP 2016-098301 A

A tetrafluoroethylene-based polymer has a low surface tension and low affinity with other components. Therefore, in a molded article formed from a composition in which other components are inorganic particles such as boron nitride particles, the physical properties of each component may not be sufficiently exhibited.
The present inventors have found that the composition of Patent Document 1 described above has a high melt viscosity during melt mixing and is difficult to improve the dispersibility of the boron nitride particles. It has been found that it is difficult to obtain a composition that is excellent in adhesiveness (peel strength) to a material and capable of forming a molded article such as a sheet.
The present inventors have found that a composition containing particles of a tetrafluoroethylene-based polymer and spherical and non-spherical boron nitride particles having a predetermined average particle size in a predetermined range has excellent dispersibility even if the average particle size is small. The molded product has a low coefficient of linear expansion, low dielectric constant and dielectric loss tangent, and is excellent in thermal conductivity, bending resistance and adhesiveness. The inventors have found that it is excellent in bendability such as bending resistance, and have arrived at the present invention.
It is an object of the present invention to provide such compositions and methods for their production, methods for producing sheets and laminates obtained from such compositions, and such laminates.

The present invention has the following aspects.
[1] containing particles of a tetrafluoroethylene-based polymer, spherical boron nitride particles having an average particle diameter of 5 μm or more and 40 μm or less, and non-spherical boron nitride particles having an average particle diameter of less than 15 μm, A composition, wherein the mass proportion of said non-spherical boron nitride particles relative to the total mass of said boron nitride particles and said non-spherical boron nitride particles is less than 30%.
[2] The composition according to [1], wherein the tetrafluoroethylene-based polymer is a hot-melt tetrafluoroethylene-based polymer.
[3] The composition according to [1] or [2], wherein the tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer having an oxygen-containing polar group.
[4] The average particle size of the tetrafluoroethylene-based polymer particles is smaller than both the average particle size of the spherical boron nitride particles and the average particle size of the non-spherical boron nitride particles, [1] to [ 3].
[5] The composition according to any one of [1] to [4], wherein the average particle size of the non-spherical boron nitride particles is smaller than the average particle size of the spherical boron nitride particles.
[6] The composition according to any one of [1] to [5], wherein the ratio of the average particle size of the spherical boron nitride to the average particle size of the non-spherical boron nitride particles is 2.5 or more. thing.
[7] The mass ratio of the tetrafluoroethylene-based polymer particles to the total mass of the tetrafluoroethylene-based polymer particles, the spherical boron nitride particles, and the non-spherical boron nitride particles is 20% or more and 80% or less. The composition according to any one of [1] to [6].
[8] The total content of the tetrafluoroethylene-based polymer particles, the spherical boron nitride particles, and the non-spherical boron nitride particles in the composition is 50% or more, [1] to [7] ] The composition according to any one of the above.
[9] The composition according to any one of [1] to [8], further comprising a liquid dispersion medium.
[10] Tetrafluoroethylene-based polymer particles, spherical boron nitride particles having an average particle size of 5 μm or more and 40 μm or less, non-spherical boron nitride particles having an average particle size of less than 15 μm, and a liquid dispersion medium The method for producing the composition according to [9], wherein the composition is sheared.
[11] The method for producing a composition according to [10], wherein the shearing treatment is performed by mixing in a tank equipped with a thin film swirl stirring mechanism or a rotation and revolution stirring mechanism.
[12] The composition according to any one of [1] to [9] is extruded to form a sheet containing the tetrafluoroethylene-based polymer, the spherical boron nitride particles, and the non-spherical boron nitride particles. A sheet manufacturing method.
[13] The composition according to any one of [1] to [9] is applied to the surface of a substrate and heated to obtain the tetrafluoroethylene-based polymer, the spherical boron nitride particles, and the non-spherical A method for producing a laminate, comprising forming a polymer layer containing boron nitride particles of and obtaining a laminate having a base material layer composed of the above base material and the above polymer layer.
[14] A substrate layer, the tetrafluoroethylene-based polymer, the spherical boron nitride particles, and the non-spherical boron nitride formed from the composition according to any one of [1] to [9] and a polymer layer containing particles.
[15] The laminate according to [14], wherein the polymer layer has a thickness of 20 μm or more and 100 μm or less.

According to the present invention, there is provided a highly dispersible composition containing tetrafluoroethylene-based polymer particles and spherical and non-spherical boron nitride particles having a predetermined average particle size within a predetermined range. Molded articles and laminates having low linear expansion coefficients, low dielectric constants and low dielectric loss tangents, and excellent thermal conductivity, bending resistance and adhesion can be formed from such compositions. Molded articles obtained from the present composition are excellent in bendability such as flex resistance and bending resistance, even when they are thin molded articles such as sheets and films.

The following terms have the following meanings.
"Average particle diameter (D50)" is the volume-based cumulative 50% diameter of particles determined by a laser diffraction/scattering method. That is, the particle size distribution is measured by a laser diffraction/scattering method, and the cumulative curve is obtained with the total volume of the group of particles being 100%.
The D50 of the particles is obtained by dispersing the particles in water and analyzing them by a laser diffraction/scattering method using a laser diffraction/scattering particle size distribution analyzer (LA-920 measuring instrument manufactured by Horiba, Ltd.).
"Melting temperature" is the temperature corresponding to the maximum melting peak of the polymer as measured by differential scanning calorimetry (DSC).
"Glass transition point (Tg)" is a value determined by analyzing a polymer by dynamic viscoelasticity measurement (DMA).
"Viscosity" is determined by measuring a composition using a Brookfield viscometer at 25°C and a rotation speed of 30 rpm. The measurement is repeated 3 times, and the average value of the 3 measurements is taken.
The “thixotropic ratio” is a value calculated by dividing the viscosity η ₁ of the composition measured at a rotation speed of 30 rpm by the viscosity η ₂ measured at a rotation speed of 60 rpm. Each viscosity measurement is repeated three times, and the average value of the three measurements is taken.
A "unit" in a polymer means an atomic group based on the monomer formed by polymerization of the monomer. The units may be units directly formed by a polymerization reaction, or may be units in which some of said units have been converted to another structure by treatment of the polymer. Hereinafter, units based on monomer a are also simply referred to as "monomer a units".

The composition of the present invention (hereinafter also referred to as "this composition") comprises particles (hereinafter also referred to as "F particles") of a tetrafluoroethylene polymer (hereinafter also referred to as "F polymer"), Spherical boron nitride particles having an average particle size of 5 μm or more and 40 μm or less (hereinafter also referred to as “spherical BN particles”) and non-spherical boron nitride particles having an average particle size of less than 15 μm (hereinafter referred to as “non-spherical BN The mass ratio of the non-spherical boron nitride particles to the total mass of the spherical boron nitride particles and the non-spherical boron nitride particles is less than 30%.

This composition has excellent dispersibility, and from this composition, the physical properties of F polymer and boron nitride particles are highly provided, the linear expansion coefficient, dielectric constant and dielectric loss tangent are low, thermal conductivity, bending resistance and Molded products with excellent adhesiveness can be formed. In particular, even a thin molded product such as a sheet or film can easily be formed to have excellent bendability such as bending resistance and bending resistance. Although the reason is not necessarily clear, it is considered as follows.

If spherical boron nitride particles with a small average particle size are added alone to a resin for the purpose of improving physical properties such as thermal conductivity, the melt viscosity of the composition will increase and the moldability will decrease, and the thermal conductivity will be reversed. , and it tends to be difficult to fully exhibit the physical properties in the molded product. In addition, when non-spherical boron nitride particles such as plate-like or scale-like particles are blended alone, they are oriented in the flow direction during melt molding. direction tends to be worse. When two kinds of particles, spherical boron nitride particles and non-spherical boron nitride particles, are mixed in a resin, improvement of these tendencies can be expected. Become.

The composition contains two types of boron nitride particles, spherical BN particles and non-spherical BN particles, each having an average particle size within a specific range. This makes it easier for the non-spherical BN particles to be sandwiched between two or more spherical BN particles inside the molded article made from the present composition. It is considered that the formation of a network between particles is promoted while the coating is performed, and this improves the thermal conductivity in the plane direction when the composition is formed into a sheet or film.

In particular, the composition contains non-spherical BN particles in a proportion less than a predetermined amount with respect to the total amount of spherical BN particles and non-spherical BN particles. It is believed that the non-spherical BN particles contained in such an excessively small amount are excellent in dispersibility and are difficult to agglomerate, promoting uniform dispersion of the F particles and the spherical BN particles. Furthermore, when the composition is processed and molded, a dense and stable packing of spherical BN particles in excess as boron nitride particles tends to form, which leads to a high degree of non-spherical BN particles in the molding. In other words, it promotes the formation of heat conduction paths by the non-spherical BN particles in the molded product, and also contributes to the improvement of the bending resistance of the molded product.
As a result, the physical properties of the F polymer and the boron nitride particles are highly provided, specifically, the coefficient of linear expansion, the dielectric constant and the dielectric loss tangent are low, and the thermal conductivity, bending resistance and adhesiveness are excellent. It is believed that thin moldings such as sheets and films were obtained from this composition.
In this specification, hereinafter, the term "sheet" is used as a generic term for both sheets and films.

The F polymer in the present invention is a polymer containing units (hereinafter also referred to as "TFE units") based on tetrafluoroethylene (hereinafter also referred to as "TFE").
The F polymer may be hot-meltable or non-hot-meltable. Here, the hot-melt polymer means a polymer having a temperature at which the melt flow rate is 1 to 1000 g/10 minutes under a load of 49 N. A non-thermally fusible polymer means a polymer that does not have 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 heat-meltable F polymer is preferably 180° C. or higher, more preferably 200° C. or higher, and even more preferably 260° C. or higher. The melting temperature of the F polymer is preferably 325° C. or lower, more preferably 320° C. or lower. The melting temperature of the F polymer is preferably 180 to 320°C. Within this range, the present composition tends to be excellent in processability, and a molded product formed from the present composition tends to be excellent in heat resistance.

The glass transition point of 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. Such F polymer having a high fluorine content has a low affinity with inorganic particles such as boron nitride particles, but due to the mechanism of action described above, according to the present invention, a composition (present composition) having excellent dispersibility can be obtained. be done.
The surface tension of the F polymer is preferably 16-26 mN/m. The surface tension of the F polymer can be measured by placing a droplet of a liquid mixture for wet tension test (manufactured by Wako Pure Chemical Industries, Ltd.) specified in JIS K 6768 on a flat plate made of the F polymer. .

F polymers include polytetrafluoroethylene (PTFE), polymers containing TFE units and ethylene-based units, polymers containing TFE units and propylene-based units, based on TFE units and perfluoro(alkyl vinyl ether) (PAVE). A polymer (PFA) containing units (PAVE units) and a polymer (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 also 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”), more preferably PPVE.

The F polymer preferably has oxygen-containing polar groups. As the oxygen-containing polar group, a hydroxyl group-containing group or a carbonyl group-containing group is preferable, and a carbonyl group-containing group is more preferable.
In this case, the F particles tend to interact with the spherical BN particles and the non-spherical BN particles, and the present composition tends to have excellent dispersibility. In addition, from the present composition, it is easy to obtain a molded article having a low coefficient of linear expansion, a low dielectric constant and a low dielectric loss tangent, and having excellent thermal conductivity and adhesiveness.
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.
Examples of 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)-), Imido residue (-C(O)NHC(O)-, etc.), formyl group, halogenoformyl group, urethane group (-NHC(O)O-), carbamoyl group (-C(O)-NH ₂ ), ureido The group (--NH--C(O)--NH ₂ ), oxamoyl group (--NH--C(O)--C(O)--NH ₂ ) and carbonate group (--OC(O)O--) are preferred, and acid anhydride is more preferred.
When the F polymer has oxygen-containing polar groups, 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. 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 WO2020/145133.

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, the former being 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"), more preferably NAH.

The F polymer is preferably a polymer having carbonyl-containing groups containing TFE units and PAVE units, comprising units based on monomers containing TFE units, PAVE units and carbonyl-containing groups, for all 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 WO2018/16644.

The F particles in the present invention are particles of the F polymer, preferably non-hollow particles. D50 of F particles is preferably 0.01 μm or more, more preferably 0.3 μm or more, and even more preferably 1 μm or more. D50 of the F particles is preferably less than 10 μm, more preferably less than 8 μm. In this case, the present composition is excellent in dispersibility and workability. In addition, from the present composition, it is easy to obtain a molded article having a low coefficient of linear expansion, a low dielectric constant and a low dielectric loss tangent, and having excellent thermal conductivity and adhesiveness (adhesion to a substrate).
The specific surface area of the F particles is preferably 1 to 25 m ² /g.
From the viewpoint of dispersion stability of the present composition, the bulk density of the F particles is preferably 0.05 g/mL or more, more preferably 0.08 g/mL or more. The bulk density of the F particles is preferably 0.5 g/mL or less, more preferably 0.4 g/mL or less.

One type of F particles may be used, or two or more types may be used. The F particles are preferably at least particles of a heat-melting F polymer, more preferably particles of a heat-melting F polymer having a melting temperature of 180 to 320° C. and having an oxygen-containing polar group. In this case, the interaction among the F particles, the spherical BN particles, and the non-spherical BN particles in the mechanism of action described above is enhanced, and aggregation of the respective particles is easily suppressed, and the dispersibility of the present composition is easily improved.

When two or more types of F particles are used, the F particles are preferably a mixture of heat-melting F polymer particles and non-heat-melting F polymer particles. In this case, the effect of suppressing aggregation by the particles of the hot-melt F polymer and the retention effect of the fibrillation of the non-heat-meltable F polymer are balanced, and the dispersibility of the present composition is likely to be improved. In addition, the molded article obtained therefrom exhibits the electrical properties of the non-thermally fusible F-polymer to a high degree, and a molded article having a particularly low dielectric loss tangent is easily obtained.
Particles of the heat-melting F polymer are preferably particles of the heat-melting F polymer having a melting temperature of 180 to 320° C., and a heat-melting F polymer having a melting temperature of 180 to 320° C. and having an oxygen-containing polar group. are more preferred. Preferred embodiments of the heat-fusible F polymer having oxygen-containing polar groups in the heat-fusible F-polymer particles are the same as the above-described preferred embodiments of the F-polymer having oxygen-containing polar groups.
Particles of non-heat-melting PTFE are preferred as the particles of non-heat-melting F polymer.
In addition, the ratio of the particles of the hot-melt F polymer to the total mass of the two or more kinds of F particles is preferably 50% by mass or less, more preferably 40% by mass or less. Moreover, the above ratio is preferably 5% by mass or more, more preferably 10% by mass or more.
The D50 of the heat-fusible F-polymer particles is preferably 1-4 μm, and the D50 of the non-heat-fusible F-polymer particles is preferably 0.1-1 μm.

The F particles may contain a resin or an inorganic compound other than the F polymer, and may form a core-shell structure in which the F polymer is the core and the resin or inorganic compound other than the F polymer is the shell. may form a core-shell structure in which a resin or an inorganic compound other than the F polymer is used as a core.
Here, examples of resins other than F polymer include aromatic polyesters, polyamideimides, polyimides and maleimides, and examples of inorganic compounds include silica and boron nitride.

The spherical BN particles contained in this composition are substantially spherical. Here, the term “substantially spherical” refers to the ratio of particles having a ratio of short diameter to long diameter (length/short diameter, aspect ratio) of 0.7 or more when observing particles with a scanning electron microscope (SEM). is 95% or more. The aspect ratio of the spherical BN particles is preferably 1-5, more preferably 1-2.
One type of spherical BN particles may be used, or two or more types may be used. When two or more types of spherical BN particles are used, the present composition tends to be excellent in dispersibility and workability. In addition, it is easy to obtain a molded article having excellent thermal conductivity and electrical properties from the present composition.
Spherical BN particles can be produced, for example, by the methods described in JP-A-2012-056818 and JP-A-5305656.
The average particle diameter (D50) of the spherical BN particles is 5 μm or more and 40 μm or less, preferably 10 μm or more, and more preferably 15 μm or more.
The spherical BN particles may be spherical aggregate particles of primary particles of boron nitride. In this case, it is preferably an aggregate of flat boron nitride primary particles such as scale-like or plate-like.

The non-spherical BN particles contained in the present composition are all boron nitride particles that are not contained in the above-described spherical BN particles, and their shape may be needle-like (fibrous), scale-like, plate-like, etc. Often scaly is more preferred. In this case, the present composition tends to be excellent in dispersibility and workability. In addition, it is easy to obtain a molded product having excellent electrical properties from the present composition.
The average particle size (D50) of the non-spherical BN particles is less than 15 μm, preferably 12 μm or less, more preferably 10 μm or less. D50 of the non-spherical BN particles is preferably 1 μm or more, more preferably 3 μm or more.
The aspect ratio of the non-spherical BN particles is preferably greater than 5, more preferably 10 or greater. The aspect ratio of the non-spherical BN particles is preferably 10,000 or less.
The non-spherical BN particles are preferably plate-like or scale-like. Such non-spherical BN particles are industrially produced. mentioned.

The composition contains F particles, spherical BN particles and non-spherical BN particles, and the mass ratio of the non-spherical BN particles to the total mass of the spherical BN elementary particles and the non-spherical BN particles is less than 30%. The mass ratio of the non-spherical BN particles to the total mass of the spherical BN elementary particles and the non-spherical BN particles is preferably 25% or less, more preferably 20% or less. Such a ratio is preferably 1% or more, more preferably 5% or more.
In the present composition, the D50 of the F particles is preferably smaller than both the D50 of the spherical BN particles and the D50 of the non-spherical BN particles.
Moreover, in the present composition, the D50 of the non-spherical BN particles is preferably smaller than the D50 of the spherical BN particles.
The ratio of D50 of spherical BN particles to D50 of non-spherical BN particles is preferably 2.5 or more, more preferably 4 or more. Also, the above ratio is preferably 8 or less.

In the present composition, the mass ratio of F particles to the total mass of F particles, spherical BN particles and non-spherical BN particles is preferably 20% or more and 80% or less. The mass ratio of the F particles to the total mass of the F particles, spherical BN particles and non-spherical BN particles is more preferably 35% or more, more preferably 40% or more. Such a ratio is more preferably 70% or less, even more preferably 60% or less.
The total content of F particles, spherical BN particles and non-spherical BN particles in the present composition is preferably 50% by mass or more.
When the content and content ratio of the F particles, the spherical BN particles and the non-spherical BN particles, and the D50 relationship of the respective particles are within such ranges, the present composition has excellent dispersibility due to the mechanism of action described above. Moreover, it is preferable from the viewpoint that a thin sheet having a low coefficient of linear expansion, a low dielectric constant and a low dielectric loss tangent, and excellent thermal conductivity, bending resistance and adhesiveness can be easily obtained from the composition.

In the present composition, the surfaces of spherical BN particles and non-spherical BN particles are preferably surface-treated with a silane coupling agent.
The silane coupling agent may be partially reacted and may form a polysiloxane skeleton.
Specific products of silane coupling agents include, for example, "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”, “KBM-13” (Shin-Etsu Chemical Co., Ltd. made).

A method of surface-treating the surfaces of spherical BN particles and non-spherical BN particles with a silane coupling agent includes, for example, a method of mixing a solution containing a silane coupling agent with spherical BN particles or non-spherical BN particles, followed by drying. is mentioned. In the mixing treatment, a mixture of the solution and the spherical BN particles or the non-spherical BN particles may be heated or hydrated to promote the reaction of the silane coupling agent. Also, the reaction catalyst may accelerate the reaction of the silane coupling agent. Furthermore, after drying, the spherical BN particles or non-spherical BN particles surface-treated with a silane coupling agent may be pulverized or classified.
The spherical BN particles and non-spherical BN particles used in the present composition may be mixed in advance, and the surface treatment with the silane coupling agent described above may be performed at once.

The present composition may further contain other inorganic particles different from the above spherical BN particles and non-spherical BN particles within a range that does not impair the effects of the present invention. The shape of the other inorganic particles may be spherical, acicular, fibrous or plate-like. Inorganic compounds in other inorganic particles include, for example, carbon fiber, glass, aluminum nitride, beryllia, silica, wollastonite, talc, cerium oxide, aluminum oxide, magnesium oxide, zinc oxide, or titanium oxide.
When the composition further contains other inorganic particles, the content thereof is preferably 1 to 20% by mass based on the total composition.

The composition may further comprise other resins different from the F polymer. Such other resins may be contained as particles in the present composition, or may be dissolved or dispersed in the liquid dispersion medium when the present composition contains a liquid dispersion medium described later.
Other resins include 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 resins.
The other resin is preferably an aromatic polymer, more preferably at least one aromatic imide polymer selected from the group consisting of aromatic polyimides, aromatic polyamic acids, aromatic polyamideimides, and aromatic polyamideimide precursors. . The aromatic polymer is preferably included in the composition as a varnish dissolved in a liquid carrier medium.
When the present composition further contains other resins, the content thereof is preferably 0.1 to 5% by mass based on the total composition.

The present composition may be in the form of a powder, a liquid containing a liquid dispersion medium (dispersion, slurry), or a paste. Alternatively, the present composition in powder form may be further melted to form the present composition in pellet form.
The present composition is preferably in a liquid form (dispersion liquid form, slurry form) further containing a liquid dispersion medium. In addition to excellent dispersibility of F particles, spherical BN particles and non-spherical BN particles when the present composition is liquid, the above-described action mechanism based on spherical BN particles and non-spherical BN particles is more easily expressed, thermal conductivity and It is easy to obtain a sheet with excellent bending resistance.
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 liquid dispersion media are used, the two liquid dispersion media are preferably compatible with each other.

The liquid dispersion medium is preferably a compound selected from the group consisting of water, amides, ketones and esters.
Amides include, for example, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropanamide, 3-methoxy-N,N-dimethylpropanamide, 3- butoxy-N,N-dimethylpropanamide, N,N-diethylformamide, hexamethylphosphoric triamide, 1,3-dimethyl-2-imidazolidinone.
Ketones include, for example, 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-valerolactone may be mentioned.

When the present composition contains a liquid dispersion medium, the content of the liquid dispersion medium is preferably in the range of 10 to 70% by mass based on the entire composition.
When the present composition contains a liquid dispersion medium, the solid content concentration in the present composition is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. The solid content concentration is preferably 90% by mass or less, more preferably 60% by mass or less.
The solid content means the total amount of substances forming the solid content in a molded product such as a sheet formed from the present composition. Specifically, the F particles, spherical BN particles and non-spherical BN particles are solids, and when the composition contains other resins or other inorganic particles, these other resins or other inorganic particles It is a solid content, and the total mass ratio of these components is the solid content concentration in the present composition.

When the present composition contains a liquid dispersion medium, the present composition preferably further contains a surfactant from the viewpoint of improving dispersion stability. Such surfactants are preferably nonionic surfactants.
Specific examples of nonionic surfactants include "Futergent" series (manufactured by Neos), "Surflon" series (manufactured by AGC Seimi Chemical), "Megafac" series (manufactured by DIC), "Unidyne" series (manufactured by DIC). Daikin Industries, Ltd.), “BYK-347”, “BYK-349”, “BYK-378”, “BYK-3450”, “BYK-3451”, “BYK-3455”, “BYK-3456” (BYK-Chemie Japan), “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 present composition contains a nonionic surfactant, the content of the nonionic surfactant in the present composition is preferably 0.1 to 10% by mass based on the entire present composition.

The composition may further contain a silane coupling agent, if necessary. Examples of the silane coupling agent include the same silane coupling agents that may be used for surface treatment of spherical BN particles and non-spherical BN particles. When the present composition contains a silane coupling agent, the content of the silane coupling agent in the present composition is preferably 0.1 to 10% by mass based on the entire present composition.

The present composition further contains 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 brightener, a colorant, Additives such as a conductive agent, a mold release agent, a surface treatment agent other than the silane coupling agent described above, and a flame retardant may be contained.

When the present composition contains a liquid dispersion medium and is liquid, the viscosity thereof is preferably 10 mPa·s or more, more preferably 100 mPa·s or more. The viscosity of the present composition is preferably 10000 mPa·s or less, more preferably 3000 mPa·s or less.
When the present composition contains a liquid dispersion medium and is liquid, its thixotropic ratio is preferably 1.0 to 3.0.
When the present composition contains water as a liquid dispersion medium, its pH is more preferably 8 to 10 from the viewpoint of improving long-term storage stability. The pH of the present composition can be controlled by adding a pH adjuster (amine, ammonia, citric acid, etc.) or a pH buffer (tris(hydroxymethyl)aminomethane, ethylenediaminetetraacetic acid, ammonium hydrogencarbonate, ammonium carbonate, ammonium acetate, etc.). can be adjusted by

This composition is mixed with F particles, spherical BN particles and non-spherical BN particles, and if necessary, other resins, other inorganic particles, liquid dispersion medium, surfactants, silane coupling agents, additives, etc. obtained by
The present composition may be obtained by mixing F particles, spherical BN particles, and non-spherical BN particles all at once, or may be separately sequentially mixed, or a masterbatch of these may be prepared in advance, and the remaining may be mixed. The order of mixing is not particularly limited, and the method of mixing may be batch mixing or mixing in multiple batches.
Mixing devices for obtaining the present composition include stirring devices equipped with blades such as Henschel mixers, pressure kneaders, Banbury mixers and planetary mixers, ball mills, attritors, basket mills, sand mills, sand grinders, dyno mills, Grinding equipment with media such as dispermat, SC mill, spike mill and agitator mill, microfluidizer, nanomizer, ultimizer, ultrasonic homogenizer, desolver, disper, high speed impeller, thin film swirling high speed mixer, rotation and revolution stirrer and dispersing devices with other mechanisms such as V-type mixers.
A planetary mixer is a stirring device having two stirring blades that rotate and revolve with each other. A thin-film swirling high-speed mixer is a stirring device that spreads F particles and a liquid dispersion medium in a thin film form on the inner wall surface of a cylindrical stirring tank, swirls them, and mixes them while exerting centrifugal force.

As an example of a method for producing the present composition containing a liquid dispersion medium, F particles, spherical BN particles, non-spherical BN particles and a liquid dispersion medium are preferably added all at once, and sheared to obtain the present composition. manufacturing methods. In this case, the shearing treatment is preferably carried out by mixing in a tank equipped with a thin film swirl stirring mechanism or a rotation and revolution stirring mechanism, such as a thin film swirl high-speed mixer, planetary mixer, or rotation/revolution. It is preferable to carry out the shearing treatment with a stirrer.
Further, as another example of the method for producing the present composition containing a liquid dispersion medium, F particles, spherical BN particles, non-spherical BN particles, and part of the liquid dispersion medium are kneaded in advance to obtain a kneaded product. and a production method in which the kneaded product is added to the remaining liquid dispersion medium to obtain the present composition. The liquid dispersion medium used for kneading and addition may be the same type of liquid dispersion medium or different types of liquid dispersion mediums. Spherical BN particles, non-spherical BN particles, other resins, other inorganic particles, surfactants, silane coupling agents, and additives may be mixed during kneading or may be mixed during addition. Mixing in kneading is preferably carried out using a planetary mixer or a rotation-revolution stirrer.

The kneaded product obtained by kneading may be in the form of a paste (such as a paste having a viscosity of 1,000 to 100,000 mPa s), or in the form of a wet powder (wet powder having a viscosity of 10,000 to 100,000 Pa s as measured by a capillograph. etc.).
The viscosity measured by a capillary graph is defined by using a capillary with a capillary length of 10 mm and a capillary radius of 1 mm, a furnace body diameter of 9.55 mm, a load cell capacity of 2 t, a temperature of 25 ° C., and a shear rate of 1 s ⁻ It is a value measured as ¹ .

A molded product such as a sheet can be obtained by subjecting the composition to a molding method such as extrusion.
When the composition is liquid containing a liquid dispersion medium, it is preferred to extrude the composition into a sheet. The sheet obtained by extrusion may be further subjected to press molding, calender molding, or the like, and cast. The sheet is preferably further heated to remove the liquid dispersion medium and calcine the F polymer.
If the composition is in powder form, it is preferred to melt extrude the composition. Extrusion can be carried out using a single-screw extruder, a multi-screw extruder, or the like.
In addition, the present composition may be injection molded to obtain a molded product.
When forming a molded article, the present composition may be directly melt-extruded or injection-molded. The composition is melt-kneaded to form pellets, and the pellets are melt-extruded or injection-molded to form articles such as sheets. may be obtained.

The thickness of the sheet obtained from this composition is preferably 20 μm or more and 100 μm or less. Such a sheet is excellent in bendability such as bending resistance and folding resistance even though it is thin, due to the above-described mechanism of action of the present composition.
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 1 ppm/°C. The coefficient of linear expansion means the value obtained by measuring the coefficient of linear expansion of the test piece in the range of 25° C. or more and 260° C. or less according to the measurement method specified in JIS C 6471:1995.
The thermal conductivity in the in-plane direction of the sheet is preferably 1.0 W/m·K or more, more preferably 3.0 W/m·K or more. The upper limit of the sheet thermal conductivity is 100 W/m·K.

A laminate can be formed by laminating such a sheet on a substrate. As a method for producing a laminate, a co-extruder is used as the extruder, a method of extruding the present composition together with the raw material of the substrate, a method of extruding the present composition on the substrate, a method of extruding the sheet and the substrate A method of thermocompression bonding the material and the like can be mentioned.
As the base material, metal substrates (copper, nickel, aluminum, titanium, metal foils of their alloys, etc.), heat-resistant resin films (polyimide, polyamide, polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamideimide, Liquid crystalline polyester, heat-resistant resin film such as tetrafluoroethylene polymer), prepreg substrate (precursor of fiber reinforced resin substrate), ceramic substrate (ceramic substrate such as silicon carbide, aluminum nitride, silicon nitride), glass substrate be done.

Examples of the shape of the base material include planar, curved, uneven, and the like. Moreover, the shape of the substrate may be any of foil, plate, film, and fiber.
The ten-point average roughness of the substrate surface is preferably 0.01 to 0.05 μm.
The surface of the substrate may be surface-treated with a silane coupling agent or plasma-treated. Examples of such silane coupling agents include 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3 - Silane coupling agents with functional groups such as isocyanatopropyltriethoxysilane are preferred.
The peel strength between the sheet and the substrate is preferably 2 kN/m or more, more preferably 2.5 kN/m or more. The peel strength is preferably 10 kN/m or less.

Further, if the present composition is applied to the surface of a substrate and heated to form a polymer layer containing F polymer, spherical BN particles and non-spherical BN particles, the substrate layer composed of the substrate and the polymer A laminate having a layer is obtained.
The polymer layer is preferably formed by disposing the present composition containing a liquid dispersion medium on the surface of a substrate, removing the dispersion medium by heating, and baking the F polymer by further heating.
Examples of the base material include those similar to the base material that can be laminated with the sheet described above, and preferred embodiments thereof are also the same.

Examples of the method for disposing the present composition include a coating method, a droplet discharge method, and an immersion method, and roll coating, knife coating, bar coating, die coating, and spraying are preferred.
Heating for removing 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 have to be completely removed, and may be removed to such an extent that the layer formed by the packing of F particles, spherical BN particles and non-spherical BN particles can maintain a self-supporting film. Also, during the heating, air may be blown to facilitate the removal of the liquid dispersion medium by air-drying.
Heating for sintering the F polymer is preferably performed at a temperature equal to or higher than the sintering temperature of the F polymer, and more preferably at 360 to 400° C. for 0.1 to 30 minutes.
A heating apparatus for each heating includes an oven and a ventilation drying oven. The heat source in the apparatus may be a contact heat source (hot air, hot plate, etc.) or a non-contact heat source (infrared radiation, etc.).
Further, each heating may be performed under normal pressure or under reduced pressure.
Moreover, the atmosphere in each 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 disposing the present composition and heating. These steps may be performed once each, or may be repeated twice or more. For example, the present composition may be placed on the surface of a substrate and heated to form a polymer layer, and further the present composition may be placed on the surface of the polymer layer and heated to form a second polymer layer. . In addition, 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.
The thickness of the polymer layer is preferably 20 μm or more and 100 μm or less. The thickness of the polymer layer is more preferably 50 μm or less, and even more preferably less than 50 μm.
Due to the mechanism of action of the present composition described above, such a polymer layer is excellent in bendability such as flex resistance and bending resistance even if it is thin.
The composition may be placed on only one surface of the substrate or may be placed on both sides of the substrate. In the former case, a laminate having a base layer and a polymer layer on one surface of the base layer is obtained, and in the latter case, a base layer and a polymer layer are obtained on both surfaces of the base layer. A laminate is obtained.

Preferred specific examples of the laminate include a metal foil and a metal-clad laminate having a polymer layer on at least one surface of the metal foil, a polyimide film, and a multilayer film having a polymer layer on both surfaces of the polyimide film. is mentioned.
The preferred range of the linear expansion coefficient of the polymer layer, the thermal conductivity in the in-plane direction, and the peel strength between the polymer layer and the substrate layer is determined by the linear expansion coefficient of the sheet obtained from the present composition described above, and the thermal conductivity in the in-plane direction. It is the same as the preferred range of the peel strength between the rate and the sheet and the substrate.

The 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 can be used for printed wiring boards, thermal interface materials, substrates for power modules, coils used in power devices such as motors, automotive engines, heat exchangers, vials, syringes, Ampoules, 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 elements, electrochemical switching elements, electrode binders, electrode separators, and electrodes (positive and negative electrodes).
The composition is also useful as an adhesive for bonding parts together. Specifically, the 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, LED It can be used for bonding chips to substrates.
In addition, the present composition can also be suitably used in applications requiring electrical conductivity, such as the field of printed electronics. Specifically, it can be used to manufacture energization elements in printed circuit boards, sensor electrodes, and the like.

Molded articles, sheets and laminates formed from the composition are useful as antenna parts, printed circuit boards, aircraft parts, automobile parts, sporting goods, food products, heat dissipation parts and the like.
Specifically, electric wire coating materials (wires for aircraft, etc.), enameled wire coating materials used for motors such as electric vehicles, electrical insulating tapes, insulating tapes for oil drilling, oil transportation hoses, hydrogen tanks, printed circuit boards materials, separation membranes (microfiltration 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, Furniture, automobile dashboards, home appliance covers, sliding parts (load bearings, yaw bearings, slide shafts, valves, bearings, bushes, seals, thrust washers, wear rings, pistons, slide switches, gears, cams, belt conveyors , food conveyor belts, etc.), tension ropes, wear pads, wear strips, tube ramps, test sockets, wafer guides, wear parts for centrifugal pumps, chemical and water supply pumps, tools (shovels, files, awls, saws, etc.), Boilers, hoppers, pipes, ovens, baking molds, chutes, racket guts, dies, toilet bowls, container coverings, mounting heat dissipation substrates for power devices, heat dissipation materials for wireless communication devices, transistors, thyristors, rectifiers, transformers, power MOS FETs , CPUs, heat radiating fins, metal heat radiating plates, blades for wind turbines, wind power generation equipment, aircraft, etc., PC and display housings, electronic device materials, interior and exterior of automobiles, processing machines and vacuum ovens that heat under low oxygen conditions, It is useful as a sealing material for plasma processing equipment, heat radiation components in processing units such as sputtering and various dry etching equipment, and electromagnetic wave shields.
Molded articles, sheets and laminates formed from the present composition are particularly suitable for electronic applications such as flexible printed wiring boards for car electronics such as LED headlamps, power control units or electric control units, rigid printed wiring boards and the like. It is useful as a substrate material, a heat dissipation sheet, a heat dissipation substrate, and a heat dissipation substrate for automobiles.
When using the molded article, sheet or laminate formed from the present composition as a heat dissipating member, the molded article, sheet or laminate may be directly adhered to a target substrate, or may be coated with a silicone adhesive layer or the like. may be attached to the target substrate via the adhesive layer.

Although the present composition, the method for producing the present composition, the method for producing a sheet, the method for producing a laminate, and the laminate have been described above, the present invention is not limited to the configurations of the above-described embodiments.
For example, the present composition and laminate may be added with any other configuration in the configurations of the above-described embodiments, or may be replaced with any configuration that exhibits similar functions. In addition, each of the present composition, sheet, or laminate manufacturing method may additionally have any other step in the configuration of the above embodiment, or may be replaced with any step that produces the same effect. you can

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these.
1. Preparation of each component [F polymer]
F particle 1: 97.9 mol%, 0.1 mol% and 2.0 mol% of TFE units, NAH units and PPVE units in this order, and a carbonyl group-containing group per 1 × 10 ⁶ main chain carbon atoms Particles (D50: 2.1 μm) of tetrafluoroethylene polymer (melting temperature: 300° C.) with 1000 particles
[Boron nitride particles]
Boron nitride particles 1: spherical boron nitride particles (D50: 12 μm)
Boron nitride particles 2: spherical boron nitride particles (D50: 45 μm)
Boron nitride particles 3: non-spherical (scaly) boron nitride particles (D50: 4 μm)
Boron nitride particles 4: Non-spherical (scaly) boron nitride particles (D50: 15 μm)
[Liquid dispersion medium]
NMP: N-methyl-2-pyrrolidone

2. Production example of composition [Example 1]
F particles 1, boron nitride particles 1, boron nitride particles 3, and NMP are kneaded in a planetary mixer to obtain a wet powder-like dough 1, and NMP is added in multiple portions and stirred, and F Liquid composition 1 containing particles 1 (30 parts by mass), boron nitride particles (30 parts by mass; boron nitride particles 1: boron nitride particles 3 = 80:20 (mass ratio)), and NMP (40 parts by mass) Obtained.
[Example 2]
F particles 1 (30 parts by mass) and boron nitride particles (30 parts by mass. Boron nitride particles 1: boron nitride A liquid composition 2 containing particles 3 (=75:25 (mass ratio)) and NMP (40 parts by mass) was obtained.

[Example 3]
F particles 1 (30 parts by mass), boron nitride particles (30 parts by mass), boron nitride particles 2: boron nitride particles 3 = 70 : 30 (mass ratio)) and NMP (40 parts by mass) to obtain a liquid composition 3.
[Example 4]
F particles 1 (30 parts by mass), boron nitride particles (30 parts by mass), boron nitride particles 1: boron nitride particles 4 = 70 : 30 (mass ratio)) and NMP (40 parts by mass) to obtain a liquid composition 4.
[Example 5]
F particles 1, boron nitride particles 1, and NMP are kneaded in a planetary mixer to obtain a wet powder-like dough 1, and NMP is added in multiple portions and stirred to obtain F particles 1 (30 parts by mass), boron nitride particles (30 parts by mass), and NMP (40 parts by mass) to obtain a liquid composition 5.

3. Production of Laminate Composition 1 was applied to the surface of a long copper foil using a bar coater to form a wet film. Then, the copper foil on which the wet film was formed was passed through a drying furnace at 110° C. for 5 minutes to dry it, thereby forming a dry film. The copper foil with dry film was then heated in a nitrogen oven at 380° C. for 3 minutes. Thus, a laminate 1 having a copper foil and a polymer layer having a thickness of 100 μm containing the fused and sintered F particles 1, the boron nitride particles 1 and the boron nitride particles 3 was produced.
Laminates 2-5 were produced from Compositions 2-5 in the same manner as Laminate 1.

4. Evaluation of laminate 4-1. Peel Strength of Laminate A rectangular test piece (length 100 mm, width 10 mm) was cut out from each laminate. Then, the copper foil and the polymer layer were separated from one longitudinal end of the test piece at a position 50 mm from one end in the longitudinal direction, and at a pulling speed of 50 mm/min at 90° to the test piece.
The maximum load applied at this time was measured as the peel strength (N/cm) and evaluated according to the following criteria.
[Evaluation criteria]
○: 2 kN/m or more △: 1 kN/m or more and less than 2 kN ×: less than 1 kN/m

4-2. Bendability 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 single polymer layer. Cut out a 5 mm square square test piece from the prepared sheet, bend it 180 ° under the condition of a curvature radius (300 μm), apply a load (50 mN, 1 minute) from above, then bend it back, and check the appearance of the test piece according to the following criteria. evaluated with
[Evaluation criteria]
◯: No abnormality in appearance is observed in the crease portion.
Δ: Whitening was observed at the crease.
x: Broken at the crease.

4-3. Thermal conductivity A 10 mm x 10 mm square test piece was cut from the center of each sheet obtained in the same manner as in 4-2, and the thermal conductivity (W / m K) in the in-plane direction was measured. Evaluated according to criteria.
[Evaluation criteria]
○: More than 2 W/m·K △: 1 W/m·K or more and 2 W/m·K or less ×: Less than 1 W/m·K Table 1 summarizes the above evaluation results.

As is clear from the above results, the present composition has excellent dispersion stability, and the laminate formed from the present composition exhibits the physical properties of the F polymer and boron nitride particles to a high degree, and exhibits peel strength (adhesiveness ), excellent thermal conductivity, and excellent bending resistance.

In addition, the entire contents of the specification, claims and abstract of Japanese Patent Application No. 2022-030107 filed on February 28, 2022 are cited here and incorporated as disclosure of the specification of the present invention. is.

Claims

tetrafluoroethylene-based polymer particles, spherical boron nitride particles having an average particle diameter of 5 μm or more and 40 μm or less, and non-spherical boron nitride particles having an average particle diameter of less than 15 μm, wherein the spherical boron nitride particles and wherein the mass proportion of said non-spherical boron nitride particles relative to the total mass of said non-spherical boron nitride particles is less than 30%.
The composition according to claim 1, wherein the tetrafluoroethylene-based polymer is a hot-melt tetrafluoroethylene-based polymer.
The composition according to claim 1 or 2, wherein the tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer having an oxygen-containing polar group.
3. The tetrafluoroethylene-based polymer according to claim 1, wherein the average particle size of the particles of the tetrafluoroethylene polymer is smaller than both the average particle size of the spherical boron nitride particles and the average particle size of the non-spherical boron nitride particles. Composition.
The composition according to claim 1 or 2, wherein the average particle size of the non-spherical boron nitride particles is smaller than the average particle size of the spherical boron nitride particles.
The composition according to claim 1 or 2, wherein the ratio of the average particle size of said spherical boron nitride to the average particle size of said non-spherical boron nitride particles is 2.5 or more.
The mass ratio of the tetrafluoroethylene-based polymer particles to the total mass of the tetrafluoroethylene-based polymer particles, the spherical boron nitride particles, and the non-spherical boron nitride particles is 20% or more and 80% or less. 3. The composition according to Item 1 or 2.
3. The composition according to claim 1, wherein the total content of the tetrafluoroethylene-based polymer particles, the spherical boron nitride particles, and the non-spherical boron nitride particles in the composition is 50% or more. thing.
The composition according to claim 1 or 2, further comprising a liquid dispersion medium.
Tetrafluoroethylene-based polymer particles, spherical boron nitride particles having an average particle size of 5 μm or more and 40 μm or less, non-spherical boron nitride particles having an average particle size of less than 15 μm, and a liquid dispersion medium are sheared. 10. A method for producing a composition according to claim 9.
The method for producing the composition according to claim 10, wherein the shearing treatment is performed by mixing in a tank equipped with a thin film swirl stirring mechanism or a rotation and revolution stirring mechanism.
A method for producing a sheet, comprising extruding the composition according to claim 1 or 2 to obtain a sheet containing the tetrafluoroethylene-based polymer, the spherical boron nitride particles, and the non-spherical boron nitride particles.
The composition according to claim 1 or 2 is applied to the surface of a substrate and heated to obtain a polymer containing the tetrafluoroethylene-based polymer, the spherical boron nitride particles, and the non-spherical boron nitride particles. A method for producing a laminate, comprising forming layers to obtain a laminate having a substrate layer composed of the substrate and the polymer layer.
a substrate layer; and a polymer layer comprising the tetrafluoroethylene-based polymer, the spherical boron nitride particles, and the non-spherical boron nitride particles, which are formed from the composition according to claim 1 or 2. Laminate with
The laminate according to claim 14, wherein the polymer layer has a thickness of 20 µm or more and 100 µm or less.