Method for producing tetrafluoroethylene-based polymer composition, composition, metal clad laminate and stretched sheet

Abstract

Provided are a composition comprising particles of a tetrafluoroethylene-based polymer and inorganic-oxide particles and having excellent dispersion stability and a method for producing the composition.　The composition production method comprises mixing inorganic-oxide particles with particles of a tetrafluoroethylene-based polymer (1) having a carbonylated group and / or a hydroxylated group to give a mixture and mixing the mixture with particles of a tetrafluoroethylene-based polymer (2), which is different from the tetrafluoroethylene-based polymer (1).

Description

[Technical Field]

[0001] The present invention relates to a method for producing a composition containing tetrafluoroethylene-based polymer particles and inorganic oxide particles, the composition, a metal clad laminate, and a stretched sheet. [Background technology]

[0002] Tetrafluoroethylene-based polymers have been attracting attention in recent years as materials for printed circuit boards due to their excellent electrical properties, such as low dielectric constant and low dielectric loss tangent. Patent Document 1 describes a molded product formed from a composition containing multiple types of tetrafluoroethylene-based polymers and inorganic particles as a high-frequency printed circuit board with high thermal conductivity, low dielectric loss tangent, and a wide range of dielectric constants. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-050860 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the composition described in Patent Document 1 does not have sufficient interaction between the components and therefore does not have sufficient dispersion stability, and therefore, molded articles formed from it have problems such as poor physical properties due to aggregation of inorganic particles, and the inorganic particles are prone to peeling off. Furthermore, there is a demand for a printed circuit board material, particularly a rigid printed circuit board material for high frequency applications, that has a further improvement in the adhesiveness of the molded article to other resins or metals and a further reduction in the linear expansion of the molded article.

[0005] The present inventors have discovered a composition containing a tetrafluoroethylene-based polymer and inorganic oxide particles, which has excellent dispersion stability, excellent adhesion to other resins and metals, and can form molded articles with a low linear expansion coefficient, a method for producing the composition, and a metal-clad laminate comprising the composition. The present invention aims to provide such a composition, a method for producing the composition, and a metal-clad laminate and stretched sheet that are particularly useful as rigid printed circuit board materials. [Means for solving the problem]

[0006] The present invention has the following aspects. [1] A method for producing a composition, comprising mixing particles of a tetrafluoroethylene-based polymer (1) having at least one of a carbonyl group-containing group and a hydroxyl group-containing group with inorganic oxide particles to prepare a mixture, and further mixing the mixture with particles of a tetrafluoroethylene-based polymer (2) different from the tetrafluoroethylene-based polymer (1). [2] The method according to [1], wherein a dispersion of particles of the tetrafluoroethylene-based polymer (2) dispersed in water is mixed with the mixture. [3] The tetrafluoroethylene-based polymer (1) has a main chain carbon number of 1 × 10 6 The method according to [1] or [2], wherein the polymer has 10 to 5,000 carbonyl-containing groups per polymer. [4] The method according to any one of [1] to [3], wherein the tetrafluoroethylene-based polymer (2) is polytetrafluoroethylene. [5] The method according to any one of [1] to [4], wherein the inorganic oxide is silicon oxide.

[0007] [6] A composition comprising particles of a tetrafluoroethylene-based polymer (1) having at least one of a carbonyl group-containing group and a hydroxyl group-containing group, particles of a tetrafluoroethylene-based polymer (2) different from the tetrafluoroethylene-based polymer, and inorganic oxide particles, wherein the average particle size of the inorganic oxide particles is in the range of 1 to 1000% of the average particle size of the particles of the tetrafluoroethylene-based polymer (1), and the content of the inorganic oxide particles is 5 to 75% by mass based on the total mass of the particles of the tetrafluoroethylene-based polymer (1), the particles of the tetrafluoroethylene-based polymer (2), and the inorganic oxide particles. [7] The composition according to [6], further comprising an aromatic polymer. [8] The composition according to [6] or [7], further comprising water. [9] The composition according to any one of [6] to [8], wherein the tetrafluoroethylene-based polymer (2) is polytetrafluoroethylene.

[10] The composition according to any one of [6] to [9], wherein the inorganic oxide is silicon oxide.

[11] The composition according to any one of [6] to

[10] , wherein the mass of the tetrafluoroethylene-based polymer (2) is 25 mass% or more based on the total mass of the tetrafluoroethylene-based polymer (1) and the tetrafluoroethylene-based polymer (2).

[0008]

[12] A metal clad laminate having a metal foil and a polymer layer formed on at least one surface of the metal foil, wherein the polymer layer contains a tetrafluoroethylene-based polymer (1) having at least one of a carbonyl group-containing group and a hydroxyl group-containing group, polytetrafluoroethylene, and inorganic oxide particles, and the content of the inorganic oxide particles is 5 to 75 mass% based on the total mass of the tetrafluoroethylene-based polymer (1), the polytetrafluoroethylene, and the inorganic oxide particles.

[13] The metal clad laminate according to

[12] , wherein the polymer layer further contains an aromatic polymer.

[14] The metal clad laminate according to

[12] or

[13] , wherein the polymer layer has a thickness of 50 μm or more.

[15] A stretched sheet that has been stretched, comprising a tetrafluoroethylene-based polymer (1) having at least one of a carbonyl group-containing group and a hydroxyl group-containing group, polytetrafluoroethylene, and inorganic oxide particles, wherein the content of the inorganic oxide particles is 5 to 75 mass% based on the total mass of the tetrafluoroethylene-based polymer (1), the polytetrafluoroethylene, and the inorganic oxide particles. [Effects of the Invention]

[0009] According to the present invention, there are provided a composition containing tetrafluoroethylene-based polymer particles and inorganic oxide particles and having excellent dispersion stability, and a method for producing the same. Such a composition has the respective physical properties of the tetrafluoroethylene-based polymer and the inorganic oxide, and can form a molded product having excellent adhesion and low linear expansion and suppressed component peeling. According to the present invention, there are provided a metal-clad laminate and a stretched sheet that are useful as printed circuit board materials, particularly rigid printed circuit board materials. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following terms have the following meanings: A "tetrafluoroethylene-based polymer" is a polymer containing units based on tetrafluoroethylene (hereinafter also referred to as "TFE"). The "melting temperature (melting point) of a polymer" is the temperature corresponding to the maximum value of the melting peak measured by differential scanning calorimetry (DSC). The "glass transition temperature (Tg) of a polymer" is a value measured by analyzing a polymer using dynamic mechanical analysis (DMA). "Particle D50" is the average particle size of a target object, and is the volume-based cumulative 50% diameter of the particle determined by laser diffraction / scattering. In other words, particle size distribution is measured by laser diffraction / scattering, and a cumulative curve is calculated with the total volume of the particle group as 100%. D50 is the particle size at the point on that cumulative curve where the cumulative volume is 50%. "D90 of particles" is the volume-based cumulative 90% diameter of particles, which is determined in the same manner as "D50". The "viscosity of a liquid" is a value measured for a target object using a Brookfield viscometer at room temperature (25°C) and a rotation speed of 30 rpm. The measurement is repeated three times, and the average value of the three measurements is used. The term "monomer-based unit" in a polymer refers to an atomic group formed directly from one monomer molecule by polymerization, or an atomic group formed by converting a part of the atomic group into a different structure by treating the resulting polymer. Hereinafter, a unit based on monomer a will also be referred to simply as a "monomer a unit."

[0011] The production method of the present invention (hereinafter also referred to as this method) is a method for producing a composition, which comprises mixing particles (hereinafter also referred to as "the present particles (1)") of a tetrafluoroethylene-based polymer (1) (hereinafter also referred to as "F polymer (1)") having at least one of a carbonyl group-containing group and a hydroxyl group-containing group with inorganic oxide particles (hereinafter also referred to as "the present inorganic particles") to form a mixture, and then further mixing the mixture with particles (hereinafter also referred to as "the present particles (2)") of a tetrafluoroethylene-based polymer (2) (hereinafter also referred to as "F polymer (2)") different from the tetrafluoroethylene-based polymer (1). Hereinafter, F polymer (1) and F polymer (2) will be collectively referred to as "F polymer." This method allows the production of compositions with excellent dispersion stability. The reason for this is not entirely clear, but the mechanism of action is presumed to be as follows.

[0012] Tetrafluoroethylene-based polymers are highly rigid and have extremely low affinity with other components, so when preparing compositions such as dispersions, their dispersibility is generally improved by shearing. However, shearing of tetrafluoroethylene-based polymers can cause deterioration such as fibrillation, leading to aggregation and a decrease in the dispersion stability of the composition. This tendency is particularly pronounced when the F polymer (2) is polytetrafluoroethylene or when the composition is a liquid composition (dispersion), particularly when the dispersion medium is water, which is highly polar. Therefore, in this method, the present particles (1) and the present inorganic particles are mixed in advance, and then the present particles (2) are mixed to produce a composition. The F polymer (1) has a predetermined functional group and is prone to forming microspherulites at the molecular aggregate level, which tend to have a micro-irregular structure on its surface. Therefore, the properties of the present particles (1) are not lost when the present particles (1) and the present inorganic particles are mixed, and the mixture is thought to form a pseudo-coalescence of the present particles (1) and the present inorganic particles. This hard coalescence containing the present inorganic particles buffers the shear force during mixing with the present particles (2), suppressing deterioration of the F polymer (2), and is highly compatible with the F polymer (2). Therefore, a composition containing the F polymer (1), the F polymer (2), and the present inorganic particles with excellent dispersion stability was obtained.

[0013] The F polymer (1) in this method has at least one of a carbonyl group-containing group and a hydroxyl group-containing group. The carbonyl group-containing group is a group containing a carbonyl group (>C(O)). Preferred carbonyl group-containing groups include a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (-OC(O)NH), an acid anhydride residue (-C(O)OC(O)-), an imide residue (-C(O)NHC(O)-, etc.), and a carbonate group (-OC(O)O-), with an acid anhydride residue being more preferred. As the hydroxyl group-containing group, a group containing an alcoholic hydroxyl group is preferred, and -CF2CH2OH and -C(CF3)2OH are more preferred.

[0014] When the F polymer (1) has a carbonyl group-containing group, the number of carbonyl group-containing groups in the F polymer is 1×10 6 The number of carbonyl-containing groups per particle is preferably 10 to 5,000, more preferably 50 to 4,000, and even more preferably 100 to 2,000. In this case, the F polymer (1) easily interacts with the inorganic particles or the F polymer (2), and the composition tends to have excellent processability and stability. The number of carbonyl-containing groups in the F polymer can be quantified by the polymer composition or the method described in WO 2020 / 145133.

[0015] When polymer F (1) has a carbonyl group-containing group, the carbonyl group-containing group may be contained in a unit contained in the polymer or in a terminal group of the polymer main chain. Examples of the latter polymer include polymers having a carbonyl group-containing group as a terminal group derived from a polymerization initiator, a chain transfer agent, etc., and polymers having a carbonyl group-containing group prepared by plasma treatment, ionizing radiation treatment, or radiation treatment.

[0016] The fluorine content of the F polymer (1) is preferably 70 to 76% by mass. An F polymer (1) with such a high fluorine content has excellent physical properties such as electrical properties of the F polymer (1), but is prone to aggregation due to low polarity. Therefore, for example, when a dispersion is prepared, its dispersibility is likely to decrease. According to this method, even in such a dispersion, the physical properties of the F polymer (1) as a whole are not impaired, and a composition with excellent dispersibility can be obtained. Furthermore, peeling of the inorganic particles from a molded article formed from the composition is suppressed, and a molded article with excellent low linear expansion can be obtained.

[0017] The melting temperature of the F polymer (1) is preferably 200° C. or higher, more preferably 260° C. or higher. The melting temperature of the F polymer (1) is preferably 325° C. or lower, more preferably 320° C. or lower. The melting temperature of the F polymer (1) is particularly preferably 260° C. or higher and 325° C. or lower. The glass transition point of the F polymer (1) is preferably 50° C. or higher, more preferably 75° C. or higher. The glass transition point of the F polymer (1) is preferably 150° C. or lower, more preferably 125° C. or lower.

[0018] As the F polymer (1), a polymer containing TFE units and ethylene units, a polymer containing TFE units and units based on perfluoro(alkyl vinyl ether) (hereinafter also referred to as PAVE) (hereinafter also referred to as PAVE units) (hereinafter also referred to as PFA), and a copolymer containing TFE and hexafluoropropylene units (hereinafter also referred to as FEP) are preferred, with PFA and FEP being more preferred, and PFA being even more preferred. These polymers may further contain units based on other comonomers. As PAVE, CF2=CFOCF3, CF2=CFOCF2CF3 and CF2=CFOCF2CF2CF3 (hereinafter also referred to as PPVE) are preferred, and PPVE is more preferred.

[0019] The F polymer (1) is preferably a polymer having a carbonyl group-containing group containing TFE units and PAVE units, more preferably a polymer containing TFE units, PAVE units, and units derived from a monomer having a carbonyl group-containing group, and even more preferably a polymer containing these units in the following amounts, in that order, relative to the total units. When such a polymer is contained, the composition tends to have excellent adhesion to the inorganic particles. Furthermore, molded articles formed from the composition tend to be dense and have excellent low linear expansion. As the monomer having a carbonyl group-containing group, itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH") are preferred. Specific examples of such F polymer (1) include the polymers described in WO 2018 / 16644.

[0020] The particles (1) are particles containing the F polymer (1), and the amount of the F polymer (1) in the particles is preferably 80% by mass or more, more preferably 100% by mass. The D50 of the present particles (1) is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less. The D50 of the present particles (1) is preferably 0.1 μm or more, more preferably 0.5 μm or more. Furthermore, the D90 of the present particles (1) is more preferably 50 μm or less. When the D50 and D90 of the present particles (1) are within the above ranges, the surface area of ​​the present particles (1) increases, and the dispersibility of the present particles (1) is likely to be further improved.

[0021] The present particles (1) may contain a polymer different from the F polymer. Specific examples of polymers different from the F polymer include heat-resistant resins such as aromatic polyesters, aromatic polyimides, aromatic polymaleimides, polyamideimides, polyphenylene ethers, polyphenylene oxides, and polymaleimides.

[0022] The present inorganic particles are inorganic oxide particles used to improve the physical properties of a molded product obtained from a composition, and the type of the inorganic particles is appropriately selected depending on the purpose of the molded product. The present inorganic particles may be fired ceramic particles. For example, when the dielectric constant of a molded product is to be improved, inorganic oxide particles with a high dielectric constant are used. The dielectric constant of the inorganic oxide particles with a high dielectric constant at 25°C is 10 or more, preferably 25 or more, and more preferably 50 or more. As such inorganic oxide particles, perovskite-type ferroelectric particles and bismuth-layered perovskite-type ferroelectric particles are preferred. Examples of perovskite-type ferroelectrics include barium titanate, lead zirconate titanate, lead titanate, zirconium oxide, and titanium oxide, while examples of bismuth-layered perovskite-type ferroelectrics include bismuth strontium tantalate, bismuth strontium niobate, and bismuth titanate.

[0023] For example, when the dielectric constant and dielectric loss tangent or linear expansion coefficient of a molded product is to be reduced, inorganic oxide particles having a low dielectric constant and dielectric loss tangent or a low linear expansion coefficient are used. As such inorganic oxide particles, beryllium oxide particles (beryllia particles), silicon oxide particles (silica particles), wollastonite particles, and magnesium metasilicate particles (steatite particles) are preferred.

[0024] For example, metal oxide particles are used to improve the thermal conductivity or scratch resistance of a molded product. The metal oxide is preferably aluminum oxide, lead oxide, iron oxide, tin oxide, magnesium oxide, titanium oxide, zinc oxide, antimony pentoxide, zirconium oxide, lanthanum oxide, neodymium oxide, cerium oxide, or niobium oxide, and more preferably aluminum oxide, which is particularly preferred because of its high thermal conductivity.

[0025] As the inorganic particles, silica particles and magnesium metasilicate particles are preferred, and silica particles are more preferred. When the inorganic particles are silica particles or magnesium metasilicate particles, the content of silica or magnesium metasilicate is preferably 80% by mass or more, more preferably 95% by mass, and is preferably 100% by mass or less, more preferably 90% by mass or less.

[0026] The shape of the inorganic particles of the present invention can be appropriately selected depending on the purpose, and can be spherical, scale-like, layer-like, flat, leaf-like, apricot-like, columnar, cockscomb-like, equiaxial, leaf-like, mica-like, block-like, flat, wedge-like, rosette-like, net-like, or prismatic, and is preferably scale-like or spherical, more preferably spherical.If spherical inorganic particles are used, the composition is likely to have excellent dispersibility and stability, and the molded product formed from the composition is likely to have excellent low linear expansion. The D50 of the present inorganic particles is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less.The D50 of the present particles is preferably 0.01 μm or more, more preferably 0.1 μm or more, and even more preferably 0.3 μm or more.

[0027] When the inorganic particles are spherical, they are preferably nearly spherical. In this case, the ratio of the minor axis to the major axis is preferably 0.5 or more, more preferably 0.8 or more. The ratio is preferably less than 1. By using such highly nearly spherical inorganic particles, the composition is likely to have excellent stability and dispersibility. Furthermore, molded articles formed from the composition are likely to have excellent adhesion and low linear expansion.

[0028] It is preferable that at least a portion of the surface of the present inorganic particles is surface-treated. In this case, the present particles (1) and the present inorganic particles are likely to form composite particles, and the composition obtained by this method is likely to have excellent dispersibility and stability. Furthermore, when heating the composition to form a molded product, the surface treatment agent is thermally decomposed to generate gas, which promotes the flow of the present inorganic particles and is thought to easily improve the uniformity of the molded product. Examples of the surface treatment agent used for the surface treatment include polyhydric alcohols such as trimethylolethane, pentaerythritol, and propylene glycol; saturated fatty acids such as stearic acid and lauric acid and esters thereof; amines such as alkanolamine, trimethylamine, and triethylamine; paraffin wax; silane coupling agents; silicones; and polysiloxanes, with silane coupling agents being preferred.

[0029] As the silane coupling agent, a silane coupling agent having a functional group is preferred, and 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, phenylaminosilane, and 3-isocyanatopropyltriethoxysilane are more preferred.

[0030] The inorganic particles may be one type of inorganic oxide particles used alone, or two or more types of inorganic oxide particles may be used in combination. Specific preferred examples of the inorganic particles include silica particles (such as the "Admafine (registered trademark)" series manufactured by Admatechs Co., Ltd.), zinc oxide particles surface-treated with an ester such as propylene glycol dicaprate (such as the "FINEX (registered trademark)" series manufactured by Sakai Chemical Industry Co., Ltd.), spherical fused silica particles (such as the "SFP (registered trademark)" series manufactured by Denka Corporation), titanium oxide particles coated with a polyhydric alcohol and an inorganic substance (such as the "Tipaque (registered trademark)" series manufactured by Ishihara Sangyo Kaisha, Ltd.), rutile-type titanium oxide particles surface-treated with an alkylsilane (such as the "JMT (registered trademark)" series manufactured by Teika Corporation), hollow silica particles (such as the "E-SPHERES" series manufactured by Taiheiyo Cement Corporation, the "Silinax" series manufactured by Nittetsu Mining Co., Ltd., and the "Ecocosphere" series manufactured by Emerson & Cumming Co., Ltd.), talc particles (such as the "SG" series manufactured by Nippon Talc Co., Ltd.), and steatite particles (such as the "BST" series manufactured by Nippon Talc Co., Ltd.).

[0031] The F polymer (2) is a tetrafluoroethylene-based polymer different from the F polymer (1), and is preferably a tetrafluoroethylene-based polymer that does not contain the carbonyl group-containing group and the hydroxyl group-containing group.

[0032] As the F polymer (2), non-thermofusible polytetrafluoroethylene (hereinafter also referred to as "non-thermofusible PTFE") is more preferable. The non-thermofusible PTFE is polytetrafluoroethylene (PTFE), and includes not only TFE homopolymers but also so-called modified PTFEs, which are copolymers of TFE with trace amounts of comonomers such as PAVE, HFP, FAE, etc. The proportion of TFE units in the non-thermofusible PTFE is preferably 99.5 mol % or more, more preferably 99.9 mol % or more, of all units.

[0033] The non-thermofusible PTFE preferably has fibrillar properties. The non-thermofusible PTFE having fibrillar properties means PTFE that can be paste-extruded as unsintered polymer powder, and is preferably polytetrafluoroethylene having a number-average molecular weight (Mn) of 200,000 or more, calculated according to the following formula (1): Mn = 2.1 × 10 10 ×ΔHc -5.16 ··· (1) In formula (1), Mn represents the number average molecular weight of PTFE, and ΔHc represents the heat of crystallization (cal / g) of PTFE measured by differential scanning calorimetry. The present particles (2) are particles containing the F polymer (2), and the amount of the F polymer (2) in the present particles (2) is preferably 80% by mass or more, more preferably 100% by mass. The D50 of the present particles (2) is preferably 20 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. The D50 of the present particles (2) is preferably 0.1 μm or more, more preferably 0.2 μm or more. Furthermore, the D90 of the present particles (2) is more preferably 20 μm or less. When the D50 and D90 of the present particles (2) are within the above ranges, the surface area is increased, and the dispersibility of the present particles is likely to be further improved.

[0034] The present particles (2), like the present particles (1), may contain a polymer different from the F polymer or an inorganic substance. Specific examples of polymers and inorganic substances different from the F polymer include the same compounds as those mentioned above.

[0035] In this method, first, the present particles (1) and the present inorganic particles are mixed. The mixing of the two is usually carried out by mixing a powder that is an aggregate of the present particles (1) (hereinafter also referred to as "powder (1)") with a powder that is an aggregate of the present inorganic particles (hereinafter also referred to as "the present inorganic powder"). The mixing method using powders is not particularly limited as long as it is a method that allows powder (1) and the present inorganic powder to be mixed uniformly. Powder (1) and the present inorganic powder may be mixed all at once, or one of them may be added in multiple batches and mixed, or they may be added continuously and mixed. Mixers used for mixing include mixers with stirring blades, Henschel mixers, ribbon blenders, rocking mixers, and vibration mixers.

[0036] When powder (1) and the present inorganic powder are mixed, it is preferable to mix them so that the present particle (1) serves as a core and the present inorganic particle adheres to the surface of this core, or the present inorganic particle serves as a core and the present particle (1) adheres to the surface of this core. To achieve this embodiment, it is preferable to mix the present particles (1) and the present inorganic particles in a manner that causes them to collide, aggregate, or the like, so that they coalesce.

[0037] In this method, the present particles (1) and the present inorganic particles can also be mixed in the presence of a liquid medium. Alternatively, the present particles (1) and the present inorganic particles can be mixed using a dispersion, such as a dispersion in which the present particles (1) are dispersed in a liquid medium. In this case, the resulting mixture contains a liquid medium. In this case, as in the above, it is preferable to mix the present particles (1) and the present inorganic particles in a manner that causes them to collide, aggregate, or otherwise adhere to each other. Specific examples of mixing in the presence of a liquid medium include simultaneous mixing of powder (1), the present inorganic powder, and a liquid medium, mixing in which a liquid medium is added to a mixture of powder (1) and the present inorganic powder, and mixing of the present inorganic powder with a dispersion in which the present particles (1) are dispersed in a liquid medium. Water is preferred as the liquid medium. Because water has high polarity and poor affinity with the F polymer, it was thought that the dispersibility of the particles (1) in such a mixture would be low. However, due to the above-mentioned mechanism of action, a mixture with excellent dispersion stability can be obtained.

[0038] When water is used, it is preferable to knead a mixture containing the present particles (1), the present inorganic particles, and water, and more preferably to mix the powder (1) and the present inorganic powder, and then add water and knead them together. For example, it is preferable to premix the powder (1) and the present inorganic powder using various mixers such as a tumbler or a Henschel mixer, and then add water to the mixture and knead it further.

[0039] It is preferable to knead the components in a closed system. For kneading, it is preferable to use a kneader equipped with a stirring tank and a single or multiple stirring blades. To obtain a high kneading effect, two or more stirring blades are preferred. The kneading method may be either batch or continuous.

[0040] As the kneader used for the batch kneading, a Henschel mixer, a pressure kneader, a Banbury mixer and a planetary mixer are preferred, and a planetary mixer is more preferred. Examples of continuous kneaders include twin-screw extrusion kneaders and millstone kneaders.

[0041] When the kneading is carried out in the presence of water, a liquid mixture containing the present particles (1) and the present inorganic particles in a slurry or sol state is obtained. When water is present, the amount of water in the mixture is preferably 10 to 70 mass %, more preferably 20 to 50 mass %. The resulting slurry or sol mixture is highly viscous and typically semi-solid. Its viscosity is typically 10,000 mPa·s or higher, and in some cases 25,000 mPa·s or higher. The viscosity is preferably 100,000 mPa·s or lower, and more preferably 80,000 mPa·s or lower.

[0042] In this method, the mixture containing the present particles (1) and the present inorganic particles is then mixed with the present particles (2) to obtain a composition. The method and mixer used for mixing the mixture with the present particles (2) are the same as those used for mixing the present particles (1) and the present inorganic particles. The present particles (2) may be mixed with the mixture as a powder, or may be mixed with the mixture as a dispersion obtained by dispersing the present particles (2) in a liquid medium in advance. Water is preferred as the liquid medium. When mixing the mixture with the present particles (2), it is preferable to use an aqueous dispersion of the present particles (2). When mixing with an aqueous dispersion of the present particles (2), the mixture may contain water. When mixing with an aqueous dispersion of the present particles (2), it is preferable to knead the mixture with the dispersion. The kneading method and kneader may be the same as those described above. Since water is highly polar and has poor affinity with the F polymer, it was thought that the dispersibility of the particles (2) would decrease during such mixing. However, due to the mechanism of action described above, a composition with excellent dispersion stability can be obtained. When a dispersion liquid in which the present particles (2) are dispersed in water is used, the amount of water in the dispersion liquid is preferably from 20 to 80% by mass, more preferably from 40 to 70% by mass.

[0043] Furthermore, when at least either the mixture or the present particles (2) contains water, from the viewpoint of the dispersibility and dispersion stability of the resulting composition, it is preferable to use a media-using disperser such as an ultrasonic homogenizer, Baind shaker, ball mill, attritor, basket mill, sand mill, sand grinder, Dyno Mill, Dispermat, SC mill, spike mill, or agitator mill, or a media-free disperser such as an ultrasonic homogenizer, Nanomizer, Dissolver, Disper, or high-speed impeller disperser for kneading, and it is more preferable to use a media-using disperser for kneading.

[0044] In this method, a third component other than the present particles (1), the present particles (2), and the present inorganic particles may be used. The third component may be mixed in advance with a liquid medium such as water before use. The third component can be used when mixing the present particles (1) and the present inorganic particles to form a mixture containing the third component, or can be used when mixing the mixture containing the present particles (1) and the present inorganic particles with the present particles (2) to produce a composition containing the third component. Examples of the third component include an ultraviolet absorber, a polymer different from the F polymer (hereinafter also referred to as "other polymer"), a surfactant, a pH adjuster, and a nonionic water-soluble polymer.

[0045] The ultraviolet absorber is preferably an ultraviolet absorber having a phenolic hydroxyl group and a nitrogen-containing heterocyclic structure, more preferably an ultraviolet absorber having a hydroxybenzophenone structure, and an ultraviolet absorber having a phenolic hydroxyl group and a triazine structure or a benzotriazole structure, the latter of which preferably has a structure in which various substituents are substituted on a hydroxyphenyltriazine structure or a hydroxyphenyl structure.

[0046] Other polymers include (meth)acrylic polymers and aromatic polymers. (Meth)acrylic polymers are a general term for polymers containing units based on acrylic acid, methacrylic acid, acrylate, or methacrylate. The glass transition temperature of the (meth)acrylic polymer is preferably 30 to 120° C., more preferably 40 to 110° C., and even more preferably 60 to 100° C. The (meth)acrylic polymer preferably has a hydroxy group. In this case, the interaction with the F polymer (1) or the F polymer (2) is also likely to be improved.

[0047] As the (meth)acrylic polymer, a (meth)acrylate polymer containing a unit based on a monomer having a hydroxy group, and a (meth)acrylate polymer having a hydroxy group at the end of the polymer chain obtained by polymerizing a (meth)acrylate in the presence of a chain transfer agent (such as an alkanethiol) and an alcohol such as methanol, ethanol, or propanol are preferred.

[0048] Examples of the (meth)acrylate having a hydroxy group include hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and (meth)acrylates obtained by adding monoglycidyl ether or glycidol to (meth)acrylic acid.

[0049] The (meth)acrylic polymer preferably contains units based on at least one (meth)acrylate selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobornyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, and benzyl (meth)acrylate.

[0050] The aromatic polymer is preferably an aromatic imide polymer, and more preferably an aromatic polyimide, an aromatic polyimide precursor which is a polyamic acid or a salt thereof, an aromatic polyamideimide, an aromatic polyamideimide precursor, an aromatic polyetherimide, or an aromatic polyetherimide precursor, and more preferably an aromatic polyimide precursor or an aromatic polyamideimide. These aromatic polymers may be modified aromatic polymers further having an acidic group such as a carboxylic acid group or a phenolic hydroxyl group introduced therein.

[0051] When water is used in this method, the aromatic polymer is preferably water-soluble. A water-soluble aromatic polymer can be prepared by adjusting the acid value or the basicity of the composition obtained by this method. For example, if the aromatic polymer is an aromatic polyamic acid, the water-soluble aromatic polymer can be prepared by reacting the aromatic polyamic acid with aqueous ammonia or an organic amine to form a polyamic acid salt. Specifically, the water-soluble aromatic polymer preferably has an acid value of 20 to 100 mg KOH / g, more preferably 35 to 70 mg KOH / g. Furthermore, in the case of a composition using a water-soluble aromatic polymer, the pH of the composition is preferably 5 to 10, more preferably 7 to 9. When the acid value of the aromatic polymer and the pH of the resulting composition are within these ranges, not only is the dispersion stability of the resulting composition improved, but the aromatic polymer is also highly dispersed when a molded product is formed from the dispersion, which facilitates improving the physical properties of the molded product, such as UV absorbency, flexibility, and adhesion. Specific examples of aromatic polymers include "Ultem 1000F3SP" (manufactured by SABIC), "HPC-1000" and "HPC-2100D" (all manufactured by Showa Denko Materials KK).

[0052] When water is used in this method, a surfactant may be used as a third component in order to improve the dispersion stability and handling properties of the resulting liquid composition. The surfactant is preferably nonionic. The hydrophilic portion of the surfactant preferably has a polyoxyalkylene chain or an alcoholic hydroxyl group. The polyoxyalkylene chain may be composed of two or more types of oxyalkylene groups, in which case the different types of oxyalkylene groups may be arranged randomly or in blocks. The oxyalkylene group is preferably an oxyethylene group.

[0053] The hydrophobic portion of the surfactant preferably has an acetylene group, a polysiloxane group, a perfluoroalkyl group, or a perfluoroalkenyl group. In other words, the surfactant is preferably a polyoxyalkylene alkyl ether surfactant, an acetylene surfactant, a silicone surfactant, or a fluorine surfactant, and more preferably a silicone surfactant. The silicone surfactant is preferably an organopolysiloxane having a polyoxyalkylene chain as the hydrophilic group and a polydimethylsiloxane structure as the hydrophobic group. When using a silicone surfactant, a polyoxyalkylene alkyl ether surfactant may be used in combination from the viewpoint of improving the long-term storage stability of the liquid composition.

[0054] Specific examples of surfactants include the "Ftergent" series (manufactured by Neos Corporation, Ftergent is a registered trademark), the "Surflon" series (manufactured by AGC Seimi Chemical Co., Ltd., Surflon is a registered trademark), the "Megafac" series (manufactured by DIC Corporation, Megafac is a registered trademark), the "Unidyne" series (manufactured by Daikin Industries, Ltd., Unidyne is a registered trademark), "BYK-347", "BYK-349", "BYK-378", "BYK-3450", "BYK-3451", "BYK-3455", "BYK-3456" (manufactured by BYK Japan), and "KF-6011" and "KF-6043" (manufactured by Shin-Etsu Chemical Co., Ltd.). Polyoxyalkylene alkyl ethers are commercially available, and specific examples include "Tergitol TMN-100X" (manufactured by The Dow Chemical Company), "Lutensol TO8," "Lutensol XL70," "Lutensol XL80," "Lutensol XL90," "Lutensol XP80," and "Lutensol M5" (all manufactured by BASF), "Newcol 1305," "Newcol 1308FA," and "Newcol 1310" (all manufactured by Nippon Nyukazai Co., Ltd.), and "Leocol TDN-90-80" and "Leocol SC-90" (all manufactured by Lion Specialty Chemicals). When a surfactant is contained, its content in the liquid composition is preferably 1 to 15% by mass, which increases the affinity between the components and tends to further improve the dispersion stability of the composition obtained by this method.

[0055] When water is used in this method, a basic compound may be used as a pH adjuster to adjust the pH of the liquid composition to 5 to 10, from the viewpoint of the stability of the resulting liquid composition after long-term storage. Examples of the basic compound include ammonia, dimethylamine, diethylamine, diisopropylamine, diethanolamine, triethanolamine, tripropanolamine, triethylamine, triamylamine, pyridine, and N-methylmorpholine. In this case, a pH buffer may be further added to stabilize the pH of the liquid composition. Examples of pH buffers include tris(hydroxymethyl)aminomethane, ethylenediaminetetraacetic acid, ammonium bicarbonate, ammonium carbonate, and ammonium acetate.

[0056] When water is used in this method, the resulting liquid composition may further contain a nonionic water-soluble polymer. In this case, the dispersion stability and rheological properties of the resulting liquid composition are likely to be further improved, and its film-forming ability tends to be improved. As a result, thick molded articles and the like can be more easily formed from this dispersion. In particular, if the water-soluble polymer has a nonionic hydroxyl group, not only will this tendency be more pronounced, but the resulting molded articles are also likely to be improved. In particular, if the water-soluble polymer has a nonionic hydroxyl group, not only will this tendency be more pronounced, but the resulting molded articles are also likely to be improved. As the nonionic water-soluble polymer, polyvinyl alcohol polymers, polyvinylpyrrolidone polymers and polysaccharides are preferred.

[0057] The polyvinyl alcohol polymer may be a partially acetylated or partially acetalized polyvinyl alcohol. Examples of polysaccharides include glycogens, amicropectins, dextrins, glucans, fructans, chitins, amyloses, agaroses, amicropectins, and celluloses, such as methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, and hydroxypropylcellulose.

[0058] As the nonionic water-soluble polymer, nonionic polysaccharides are more preferred, and nonionic celluloses are particularly preferred. Preferred nonionic celluloses include hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose. Specific examples of such nonionic polysaccharides include the "Sunrose (registered trademark)" series (manufactured by Nippon Paper Industries Co., Ltd.), the "Metolose (registered trademark)" series (manufactured by Shin-Etsu Chemical Co., Ltd.), and "HEC CF Grade" (manufactured by Sumitomo Seika Chemicals Co., Ltd.).

[0059] When the liquid composition obtained by this method contains a nonionic water-soluble polymer, its amount is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, based on the total mass of the liquid composition. Furthermore, this amount is preferably 5% by mass or less. The ratio of the mass of the water-soluble polymer to the total mass of the present particles (1) and (2) in the liquid composition is preferably 0.01 or more. Furthermore, this ratio is preferably 0.1 or less.

[0060] In this method, components other than the present particles (1), the present particles (2), the present inorganic particles, and the third component may be used. Examples of other components include organic substances such as organic particles, organic pigments, metal soaps, lubricants, organic monomers, and organic oligomers with a degree of polymerization of 50 or less, thixotropic agents, viscosity modifiers, antifoaming agents, silane coupling agents, dehydrating agents, plasticizers, weathering agents, antioxidants, heat stabilizers, lubricants, antistatic agents, brighteners, colorants, conductive agents, release agents, surface treatment agents, and flame retardants.

[0061] The composition of the present invention (hereinafter also referred to as "the composition") contains the present particles (1), the present particles (2), and the present inorganic particles, the average particle size of the present inorganic particles being in the range of 1 to 1000% of the average particle size of the present particles (1), and the content of the present inorganic particles being 5 to 75% by mass based on the total mass of the present particles (1), the present particles (2), and the present inorganic particles. The composition is preferably a composition produced by the method of the present invention. The types and average particle sizes of the present particles (1), the present particles (2) and the present inorganic particles are as described above. In the present composition, however, the average particle size of the present inorganic particles is in the range of 1 to 1000%, preferably 5 to 300%, more preferably 10 to 100% of the average particle size of the present particles (1). A more preferred specific embodiment is one in which the D50 of the present particles (1) is 0.1 to 20 μm, the D50 of the present inorganic particles is 0.01 to 20 μm, and the average particle size of the present inorganic particles is in the range of 20 to 100% of the average particle size of the present particles (1).

[0062] The content of the present particles (1) in the present composition is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total mass of the present particles (1), the present particles (2), and the present inorganic particles, and is preferably 60% by mass or less, more preferably 30% by mass or less. The content of the particles (2) in the composition is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total mass of the particles (1), (2), and the inorganic particles, and is preferably 60% by mass or less, more preferably 30% by mass or less.

[0063] The content of the F polymer (2) in the composition is preferably 25% by mass or more, more preferably 50% by mass or more, based on the total mass of the F polymer (1) and the F polymer (2). The content of the F polymer (2) in the composition is preferably 90% by mass or less, more preferably 80% by mass or less, based on the total mass of the F polymer (1) and the F polymer (2). The content of the present inorganic particles in the present composition is preferably 40% by mass or more and 70% by mass or less, based on the total mass of the present particles (1), the present particles (2) and the present inorganic particles.

[0064] When the present composition contains a liquid medium such as water, the components other than the liquid medium in the present composition (hereinafter also referred to as "the present liquid composition") (hereinafter referred to as "the present liquid composition") (solid content) include the present particles (1), (2), and the present inorganic particles. The solid content in the present liquid composition also includes other components in the present liquid composition other than the present particles (1), (2), and the present inorganic particles. From the viewpoint of easily obtaining a thick molded product from the present liquid composition, the solid content concentration in the present liquid composition is preferably 20% by mass or more, more preferably 40% by mass. Furthermore, from the viewpoint of the dispersibility of the present liquid composition, the solid content concentration is preferably 80% by mass or less, more preferably 60% by mass or less. The solid content may contain components other than the present particles (1), (2), and the present inorganic particles, and the total amount of the present particles (1), (2), and the present inorganic particles in the solid content is preferably 80% by mass or more, more preferably 90% by mass or more, based on the total mass of the solid content.

[0065] Specific examples of other components in the present liquid composition include the third component described above, and more preferred examples include aromatic polyimides for the reasons described above, with aromatic polyimide precursors and aromatic polyamideimide precursors being particularly preferred.

[0066] The viscosity of the present liquid composition is preferably 50 mPa·s or more, more preferably 75 mPa·s or more, and even more preferably 100 mPa·s or more. The viscosity of the present liquid composition is preferably less than 10,000 mPa·s, more preferably 5,000 mPa·s or less, and even more preferably 1,000 mPa·s or less. The present liquid composition having such a viscosity has excellent coatability and uniformity. The thixotropy ratio of the present liquid composition is preferably 1.0 to 2.2. A present liquid composition having such a thixotropy ratio exhibits excellent coatability and uniformity. The thixotropy ratio is calculated by dividing the viscosity of the present liquid composition measured at a rotation speed of 30 rpm by the viscosity of the present liquid composition measured at a rotation speed of 60 rpm. From the viewpoint of preventing a decrease in uniformity of component distribution and voids in the molded product obtained from the liquid composition, the foam volume ratio in the liquid composition is preferably less than 10%, more preferably less than 5%, and is preferably 0% or more. The foam volume ratio is calculated by dividing the volume of the liquid composition (V N ) and the combined volume of the bubbles when it is decompressed to 0.003 MPa (V V ) and the value is calculated using the following formula. Foam volume ratio [%] = 100 × (V V -V N ) / V N is.

[0067] The present liquid composition preferably has excellent long-term storage stability, and preferably has a dispersion rate of 60% or more after long-term storage. The "dispersibility after long-term storage" is a value calculated using the following formula from the height of the entire liquid composition in the vial and the height of the dispersion layer after sealed storage when 20 mL of the liquid composition is placed in a 30 mL vial and sealed and stored at 25°C for 30 days. If no dispersion layer is observed and there is no change in the state after sealed storage, the dispersibility is considered to be 100%, assuming that there is no change in the overall height of the liquid composition. The higher the dispersibility, the better the dispersion stability. Dispersion rate (%) = (height of dispersion layer) / (height of entire liquid composition) × 100

[0068] The present composition and the present liquid composition can be obtained by the above-mentioned present method, which uses the present particles (1), the present particles (2), and the present inorganic particles, and, if necessary, a liquid medium such as water, in predetermined amounts, to obtain the present composition and the present liquid composition. Furthermore, by appropriately using the third component or other components in this method, the present composition and the present liquid composition containing these components can be obtained.

[0069] When the present composition does not contain a liquid medium such as water, the present composition is in a powder form. The present powder composition can be used to form a coating film, such as a powder coating. The present powder composition can also be melt-kneaded with the third component and other components as needed, and the resulting melt-kneaded product can be used as a molding material. Furthermore, the present powder composition can be melt-extruded to form molding materials in the form of pellets, granules, or the like. The powdered composition or the molding material obtained therefrom can be melt-molded to obtain a molded product such as a film containing the F polymer (1), the F polymer (2), and the inorganic particles. Examples of melt-molding include extrusion molding and injection molding, with extrusion molding being preferred. Extrusion molding can be carried out using a single-screw extruder, a multi-screw extruder, or the like.

[0070] From this composition, a laminate can be formed having a polymer layer containing F polymer (1), F polymer (2), and the inorganic particles, and a substrate. When the composition does not contain a liquid medium such as water, methods for producing a laminate include using a co-extruder as the extruder to extrude the composition or a molding material obtained from the composition together with the raw materials for the substrate, extrusion molding the composition or a molding material obtained from the composition onto the substrate, or thermocompression bonding an extrusion molded product of the composition or a molding material obtained from the composition to the substrate. Examples of substrates include those similar to those in the laminate formed from the liquid composition described below. A preferred embodiment of the polymer layer is the F layer described below.

[0071] In the case of the present liquid composition, a laminate having a substrate and a polymer layer can be produced by applying the present liquid composition to the surface of a substrate and heating it to form a polymer layer containing F polymer (1), F polymer (2), and the present inorganic particles. Suitable embodiments of the laminate include a metal-clad laminate having a metal foil and a polymer layer formed on at least one surface thereof, and a multilayer film having a resin film and a polymer layer formed on at least one surface thereof. The polymer layer is preferably an F layer, as described below.

[0072] The metal foil in the metal clad laminate is preferably copper foil. Such metal clad laminates are particularly useful as printed circuit board materials. The metal foil may be a low-roughness metal foil, for example, a metal foil having a ten-point average roughness of 0.01 to 0.1 μm. The resin film in the multilayer film is preferably a polyimide film, and such a multilayer film is useful as a wire covering material and a printed circuit board material.

[0073] In the production of the laminate, it is sufficient that a polymer layer is formed on at least one surface of the substrate, and a polymer layer may be formed on only one surface of the substrate, or on both surfaces of the substrate. The surface of the substrate may be surface-treated with a silane coupling agent or the like. When applying the liquid composition, a coating method such as spraying, roll coating, spin coating, gravure coating, microgravure coating, gravure offset coating, knife coating, kiss coating, bar coating, die coating, fountain-meyer bar coating, or slot die coating can be used.

[0074] The polymer layer is preferably a layer formed by removing water by heating and then baking the polymer by heating (hereinafter also referred to as "layer F"). It is preferable to blow air in the water removal step.

[0075] After removing the water, the substrate is preferably heated to a temperature range where the F polymer is baked, and the polymer is preferably baked, for example, in the range of 300 to 400° C. The F layer preferably contains a baked product of at least one of the F polymer (1) and the F polymer (2). As described above, the F layer is formed through the steps of applying, drying, and baking the present liquid composition. These steps may be performed once or twice or more times. For example, the present liquid composition is applied and then heated to remove water to form a coating film. The present liquid composition may be further applied onto the formed coating film, and the liquid medium such as water may be removed by heating, and the polymer may be baked by further heating to form the coating film. From the viewpoint of easily obtaining a thick film with excellent smoothness, the steps of applying, drying, and baking the present liquid composition may be performed multiple times.

[0076] The thickness of the F layer is preferably 0.1 μm or more, more preferably 1 μm or more. The upper limit of the thickness is 200 μm. Within this range, an F layer with excellent crack resistance can be easily formed. The peel strength between the F layer and the substrate layer is preferably 10 N / cm or more, more preferably 15 N / cm or more. The peel strength is preferably 100 N / cm or less. By using this liquid composition, such a laminate can be easily formed without impairing the physical properties of the F polymer in the F layer. The porosity of the F layer is preferably 5% or less, more preferably 4% or less. The porosity is preferably 0.01% or more, more preferably 0.1% or more. The porosity is determined by determining the void areas of the F layer through image processing of an SEM photograph of the cross section of a molded product observed using a scanning electron microscope (SEM), and then dividing the area occupied by the void areas by the area of ​​the F layer (%). The area occupied by the void areas is determined by approximating the void areas as circles.

[0077] Examples of the substrate material include metals such as copper, nickel, aluminum, titanium, and alloys thereof; heat-resistant resins such as polyimide, polyarylate, polysulfone, polyarylsulfone, polyamide, polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamideimide, liquid crystalline polyester, and liquid crystalline polyesteramide; and glass. The substrate may have a flat, curved, or irregular shape, and may also be in the form of a foil, plate, film, or fiber. Examples of the substrate include metal substrates such as metal foil, heat-resistant resin films, heat-resistant resin sheets, fiber-reinforced resin substrates, prepreg sheets that are precursors of fiber-reinforced resin substrates, glass films, and glass sheets. Specific examples of laminates include a metal-clad laminate having a metal foil and an F layer on at least one surface of the metal foil, and a multilayer film having a polyimide film and an F layer on both surfaces of the polyimide film. These laminates have excellent physical properties such as electrical properties and are suitable as printed circuit board materials. Specifically, such laminates can be used to produce flexible printed circuit boards and rigid printed circuit boards.

[0078] One embodiment of the laminate is a laminate of prepreg / F layer / metal foil. The substrate is preferably a prepreg having a polymer layer on the surface of glass cloth, obtained by impregnating glass cloth with the heat-resistant resin or tetrafluoroethylene-based polymer. The polymer layer may be formed from a plurality of polymer layers, and in such a case, each polymer layer is preferably formed from a different polymer. Having an F layer between the prepreg and the metal foil is preferable because the prepreg and the metal foil are less likely to peel off.

[0079] Such laminates can be used for applications such as insulating layers for printed wiring boards, thermal interface materials, power module substrates, and coils used in power devices such as motors, impregnated therein, and then dried to form thermally conductive, heat-resistant coatings; for bonding ceramic and metal parts together in automotive engines; for imparting corrosion resistance to heat exchangers and the fins or tubes that make them up; and for coating the interior and exterior of glass containers. They are particularly suitable for coatings that impart impact resistance. Laminates of F layers and substrates are useful for antenna components, printed circuit boards, aircraft parts, automotive parts, sports equipment, food industry supplies, heat dissipation components, paints, cosmetics, and the like. In the case of printed circuit boards, they can also be used as a new printed circuit board material to replace conventional glass epoxy boards, preventing temperature rise in printed circuit boards with densely packed electronic components.

[0080] Specifically, these include wire coating materials for aircraft wires and the like, enameled wire coating materials used in motors for electric vehicles and the like, electrical insulating tape, insulating tape for oil drilling, materials for printed circuit boards, separation membranes such as microfiltration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, and gas separation membranes, electrode binders for lithium secondary batteries and fuel cells, copy rolls, covers for furniture, automobile dashboards, and home appliances, load bearings, sliding shafts, valves, bearings, bushings, seals, thrust washers, wear rings, pistons, slide switches, gears, cams, sliding parts such as belt conveyors and food transport belts, wear pads, wear strips, tube lamps, test sockets, wafer guides, wear parts for centrifugal pumps, hydrocarbon, chemical, and water supply pumps, tools such as shovels, files, saws, and other tools, boilers, hoppers, pipes, ovens, baking molds, chutes, dies, toilets, container coating materials, power devices, transistors, thyristors, rectifiers, transformers, and power MOS It is useful for FET, CPU, heat sink, and metal heat sink. More specifically, the material is useful as a sealing material for processing machines, vacuum ovens, plasma processing equipment, etc. that are heat-treated under low-oxygen conditions, such as housings for personal computers and displays, electronic device materials, and the interior and exterior of automobiles, as well as heat-dissipating parts in processing units such as sputtering and various dry etching equipment.

[0081] By impregnating a woven fabric with the liquid composition and drying it by heating, an impregnated woven fabric is obtained in which the F polymer and the inorganic particles are impregnated into the woven fabric. The impregnated woven fabric can also be said to be a coated woven fabric in which the woven fabric is coated with an F layer. The woven fabric is preferably a glass fiber woven fabric, a carbon fiber woven fabric, an aramid fiber woven fabric, or a metal fiber woven fabric, and more preferably a glass fiber woven fabric or a carbon fiber woven fabric. The woven fabric may be treated with a silane coupling agent to improve adhesion to the F layer. The total content of the F polymer in the woven fabric is preferably 30 to 80 mass%. Methods for impregnating the woven fabric with the liquid composition include immersing the woven fabric in the liquid composition and applying the liquid composition to the woven fabric.

[0082] When drying the woven fabric, the F polymer may be calcined. The F polymer may be calcined by passing the woven fabric through a forced-air drying oven in an atmosphere of 300 to 400°C. The drying of the woven fabric and the calcination of the F polymer may be carried out in one step. This woven fabric has excellent properties, such as high adhesion (bonding) between the F layer and the woven fabric, high surface smoothness, and little distortion. By thermocompression bonding this woven fabric and metal foil, a metal clad laminate with high peel strength and resistance to warping can be obtained, which can be suitably used as a printed circuit board material.

[0083] Furthermore, in the production of the present woven fabric, a woven fabric impregnated with the present liquid composition may be applied to the surface of a substrate and heated and dried to form an impregnated woven fabric layer containing the F polymer, the present inorganic particles, and the woven fabric, thereby producing a laminate in which the substrate and the impregnated woven fabric layer are laminated in this order. The manner in which this is done is not particularly limited. For example, by applying a woven fabric impregnated with the present liquid composition to part or all of the inner wall surface of a component such as a tank, pipe, or container, and then heating the component while rotating, an impregnated woven fabric layer can be formed on part or all of the inner wall surface of the component. This production method is also useful as a method for lining the inner wall surface of components such as tanks, pipes, and containers.

[0084] The present liquid composition has excellent dispersion stability and can be efficiently impregnated into porous or fibrous materials. Examples of such porous or fibrous materials include materials other than the woven fabrics described above, specifically, plate-like, columnar, or fibrous materials. These materials may be pretreated with a curable resin, a silane coupling agent, or the like, and may further be filled with inorganic oxide particles, etc. Furthermore, these materials may be twisted together to form threads, cables, or wires. When twisting, an intervening layer made of another polymer, such as polyethylene, may be disposed. An example of an embodiment in which such a material is impregnated with the present liquid composition to produce a molded product is an embodiment in which the present liquid composition is impregnated into a fibrous material carrying a curable resin or its cured product.

[0085] Examples of fibrous materials include high-strength, low-elongation fibers such as carbon fiber, aramid fiber, and silicon carbide fiber. Preferred curable resins include thermosetting resins such as epoxy resin, unsaturated polyester resin, and thermosetting polyurethane resin. A specific example of such an embodiment is a composite cable formed by impregnating a cable made of twisted carbon fibers carrying a thermosetting resin with the liquid composition and then heating the cable to bake the F polymer. Such composite cables are useful as cables for large structures, ground anchors, oil drilling, cranes, cableways, elevators, agriculture, forestry, and fisheries, and for slings.

[0086] A preferred embodiment of the laminate is a metal clad laminate (hereinafter also referred to as "the laminate") having a metal foil and the polymer layer formed on at least one surface of the metal foil, wherein the polymer layer contains F polymer (1), polytetrafluoroethylene, and the present inorganic particles, and the content of the present inorganic particles is 5 to 75 mass% relative to the total mass of the F polymer (1), polytetrafluoroethylene, and the present inorganic particles (hereinafter referred to as "total mass"). Due to the inclusion of F polymer (1), this laminate not only has high adhesion between the polymer layer and the metal foil, but also tends to have high uniformity of polytetrafluoroethylene and the inorganic particles in the polymer layer, and has electrical properties and mechanical properties such as resistance to warping and flexibility, making it useful as a printed circuit board material.

[0087] This tendency is more likely to be improved when the relationship between the contents of the F polymer (1), polytetrafluoroethylene, and the present inorganic particles is within the ranges shown below. That is, the content of the F polymer (1) in the polymer layer is more preferably 10% by mass or more, more preferably 30% by mass or less, and particularly preferably 20% by mass or less, based on the total mass.

[0088] The content of polytetrafluoroethylene in the polymer layer is preferably 5% by mass or more, more preferably 10% by mass or more, relative to the total mass, and is preferably 60% by mass or less, more preferably 30% by mass or less. The content of the inorganic particles in the polymer layer is preferably 5% by mass or more, more preferably 40% by mass or more, based on the total mass, and is preferably 80% by mass or less, more preferably 70% by mass or less.

[0089] Furthermore, the mass of polytetrafluoroethylene in the polymer layer is preferably 50% by mass or more, more preferably more than 50% by mass, based on the total mass of the F polymer (1) and polytetrafluoroethylene in the polymer layer. The mass of polytetrafluoroethylene in the polymer layer is preferably 90% by mass or less, more preferably 80% by mass or less, based on the total mass of the F polymer (1) and polytetrafluoroethylene in the polymer layer.

[0090] The thickness of the polymer layer in the present laminate is preferably 50 μm or more, more preferably 100 μm or more. The upper limit of the thickness is 1000 μm. Due to the above-mentioned tendency, a metal clad laminate having such a thick polymer layer is less likely to warp due to the inclusion of the present inorganic particles, and is therefore particularly useful as a rigid printed circuit board material.

[0091] The polymer layer in the present laminate preferably further contains an aromatic polymer, more preferably an aromatic polyamide or aromatic polyimideamide. In this case, the binder effect of the aromatic polymer increases the density between the components and the adhesion between the metal foil and the polymer layer, further reducing powder shedding of components from the polymer layer and warping of the present laminate. Furthermore, the ultraviolet absorption ability of the aromatic polymer improves the UV absorption of the polymer layer, which tends to improve the UV laser processability of the present laminate. Therefore, the present laminate is particularly useful as a rigid printed circuit board with a thick polymer layer.

[0092] Alternatively, the present composition may be extrusion-molded as described above and then stretched to form a stretched sheet, or the metal foil of the present laminate may be removed and the resulting polymer layer may be stretched to form a stretched sheet. Such a stretched sheet may be formed by molding the present composition, in which the F polymer (2) is polytetrafluoroethylene, into a sheet and then stretching it. Such a stretched sheet is a sheet in which the present inorganic particles are firmly supported by the action of the F polymer (1), and which has the physical properties of expanded polytetrafluoroethylene, such as porosity and mechanical strength. Such a stretched sheet is also useful as a printed circuit board material, having high adhesion, a low linear expansion coefficient, and excellent electrical properties.

[0093] A preferred embodiment of such a stretched sheet is a stretched sheet (hereinafter also referred to as "this stretched sheet") that contains F polymer (1), polytetrafluoroethylene, and the present inorganic particles, and that has been subjected to a stretching treatment, and in which the content of the present inorganic particles is 5 to 75 mass% based on the total mass of F polymer (1), polytetrafluoroethylene, and the present inorganic particles. The relationship between the contents of the F polymer (1), polytetrafluoroethylene, and inorganic particles in the present stretched sheet is the same as the relationship between the contents in the present laminate. The stretching device may be a biaxial stretching device, and the stretching conditions may be a speed of 5 to 1000% / sec and a stretch ratio of 200% or more.

[0094] As described above, the present invention provides a method for producing a composition containing F polymer particles and the present inorganic particles, which has excellent stability and dispersibility, and the composition. It also provides a laminate and a stretched sheet containing the composition, which are useful as printed circuit board materials and have electrical properties and mechanical properties such as resistance to warping and flexibility.

[0095] Although the present method, the present composition, the present laminate, and the present stretched sheet have been described above, the present invention is not limited to the configurations of the above-described embodiments. For example, the method may include any other step in addition to the configuration of the above embodiment, or may be replaced with any other step that produces a similar effect.Furthermore, the composition, the laminate, and the stretched sheet may include any other step in addition to the configuration of the above embodiment, or may be replaced with any other step that produces a similar function. [Example]

[0096] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. 1. Preparation of each component and part [F Polymer] Powder A: Contains 97.9 mol% of TFE units, 0.1 mol% of NAH units, and 2.0 mol% of PPVE units, in that order, and has a carbonyl group-containing group with a main chain carbon number of 1 × 10 6 A powder consisting of particles with a D50 of 2.1 μm, made of F polymer (1) with a melting temperature of 300°C and 1000 particles per particle. Dispersion B: An aqueous dispersion in which PTFE particles having a D50 of 0.3 μm made of a non-thermofusible PTFE F polymer (2) are dispersed in water, the aqueous dispersion containing 60% by mass of PTFE particles (manufactured by AGC, "Product No. AD-911E") Powder C: A powder consisting of an F polymer containing 98.5 mol% TFE units and 1.5 mol% PPVE units, in that order, with no carbonyl group-containing groups, a melting point of 300°C, and particles with a D50 of 2.4 μm. [Inorganic oxides] Powder G: A powder consisting of spherical silica with a D50 of 0.5 μm, surface-treated with phenylaminosilane [Imide resin varnish] Varnish A: Aqueous varnish containing a precursor of aromatic polyamideimide (PAI. Acid value: 50 mg KOH / g) [Surfactants] Surfactant A: Polyoxyalkylene-modified polydimethylsiloxane with dimethylsiloxane units in the main chain and oxyethylene groups in the side chains [Water-soluble polymer] Water-soluble polymer A: Hydroxyethyl cellulose, a nonionic polysaccharide Water-soluble polymer B: Carboxymethylcellulose, an anionic polysaccharide

[0097] 2. Example of production of liquid composition (part 1) (Example 1-1) A mixture was obtained by dry blending powder A and powder G. The mixture, water, and surfactant A were added to a planetary mixer and kneaded to obtain a mixture containing powder A particles (18.5 parts by mass), powder G particles (60 parts by mass), surfactant A (1 part by mass), and water (40 parts by mass) with a viscosity of 28,000 mPa s. The above mixture was placed in a pot, and then the mixture of Dispersion B and Varnish A and water were added in several batches and stirred to obtain a liquid composition P with a viscosity of 400 mPa s, containing F polymer (1) particles (18.5 parts by mass), PTFE particles (20 parts by mass), spherical silica particles (60 parts by mass), PAI (1.5 parts by mass), surfactant (1 part by mass), and water (100 parts by mass). The dispersion rate of the obtained liquid composition P after long-term storage was 60% or more, and redispersibility after dispersion rate measurement was also good.

[0098] (Example 1-2) A mixture was obtained in the same manner as in Example 1-1, except that Powder A, Powder G, water, and Surfactant A were separately charged into a planetary mixer, and then Liquid Composition Q was prepared from the mixture. Liquid Composition Q had a viscosity of 600 mPa s, and the dispersibility of Liquid Composition Q after long-term storage was 60% or more, but the redispersibility after dispersibility measurement had decreased.

[0099] (Example 1-3) Liquid composition R was obtained in the same manner as in Example 1-1, except that powder A was changed to powder C. The dispersion rate of liquid composition R after long-term storage was less than 60%. Furthermore, after the dispersion rate measurement, it was difficult to redisperse liquid composition R.

[0100] (Example 1-4) Powder A, dispersion B, varnish A, surfactant A, and water were mixed to prepare a liquid mixture containing F polymer (1) particles (18.5 parts by mass), PTFE particles (20 parts by mass), PAI (1.5 parts by mass), surfactant (1 part by mass), and water (100 parts by mass). An attempt was made to prepare a liquid composition by adding powder G (60 parts by mass) to this mixture; however, the composition thickened with the addition of powder G, and its dispersion stability decreased. As a result, it was not possible to directly form a liquid composition containing water (100 parts by mass) with a viscosity of 1000 mPa·s or less.

[0101] 3. Example of laminate manufacturing The liquid composition P produced in Example 1-1 was applied to the surface of a long copper foil (thickness: 18 μm) using a bar coater to form a wet film. The copper foil on which the wet film had been formed was then passed through a drying oven at 110°C for 5 minutes and dried by heating to obtain a dry film. The dry film was then heated at 380°C for 3 minutes in an oven under a nitrogen gas atmosphere. This produced a laminate 1 having a copper foil and, on its surface, a polymer layer containing F polymer (1), PTFE, spherical silica particles, and PAI, with a thickness of 100 μm as a molded product.

[0102] The copper foil of the laminate 1 was removed by etching with an aqueous ferric chloride solution to produce a single polymer layer, and the dielectric loss tangent measured by the SPDR (split post dielectric resonance, measurement frequency: 10 GHz; the same applies below) method was 0.0010 or less. The copper foil of Laminate 1 was removed by etching with an aqueous ferric chloride solution to produce a single polymer layer, and a 180 mm square test piece was cut out. The cut test piece was measured at 25°C or higher and 260°C or lower according to the measurement method specified in JIS C 6471:1995. The linear expansion coefficient of the test piece was 30 ppm / °C or lower.

[0103] A rectangular test piece measuring 100 mm in length and 10 mm in width was cut out from the laminate 1. The test piece was fixed at a position 50 mm from one end in the longitudinal direction, and the copper foil and the polymer layer were peeled off from one end in the longitudinal direction at a 90° angle to the test piece at a pulling rate of 50 mm / min. The maximum load at the time of peeling was taken as the peel strength (N / cm). The peel strength was 10 N / cm or more. Furthermore, the inorganic oxide particles 1 were firmly supported in the polymer layer 1 and did not fall off.

[0104] When liquid composition P was replaced with liquid composition R to produce a laminate having a polymer layer with a thickness of 100 μm as a molded product, powder fell off from the polymer layer significantly, and a laminate having a smooth polymer layer could not be obtained.

[0105] 4. Example of liquid composition production (part 2) (Example 2-1) A mixture was obtained by dry blending powder A and powder G. The mixture, water, water-soluble polymer A, and surfactant A were charged into a planetary mixer and kneaded to obtain a mixture containing powder A particles (18.5 parts by mass), powder G particles (60 parts by mass), water-soluble polymer A (1 part by mass), surfactant A (1 part by mass), and water (40 parts by mass). The above mixture was placed in a pot, and then the mixture of Dispersion B and Varnish A and water were added in several batches and stirred to obtain a liquid composition S having a viscosity of 500 mPa·s, containing F polymer (1) particles (18.5 parts by mass), PTFE particles (20 parts by mass), spherical silica particles (60 parts by mass), PAI (1.5 parts by mass), water-soluble polymer (1 part by mass), surfactant (1 part by mass), and water (100 parts by mass). The dispersion rate of liquid composition S after long-term storage was 60% or more, and redispersibility after dispersion rate measurement was also good.

[0106] (Example 2-2) A mixture was obtained in the same manner as in Example 1-1, except that the water-soluble polymer A was changed to the water-soluble polymer B, and a liquid composition T was prepared therefrom. 5. Evaluation example of laminate Laminate 2 was obtained in the same manner as in "3. Example of Laminate Production" above, except that liquid composition P was changed to liquid composition S, and laminate 3 was obtained in the same manner, except that liquid composition P was changed to liquid composition T. The dielectric loss tangent of a single polymer layer prepared by removing the copper foil of laminate 2 by etching with an aqueous ferric chloride solution was 0.0010 or less, and the dielectric loss tangent of a single polymer layer prepared from laminate 3 was greater than 0.0010.

[0107] Furthermore, the amount of liquid composition applied was adjusted as in "3. Example of laminate production" above, and the thickness of the polymer layer that could be formed in one polymer layer formation process was evaluated for Liquid Compositions P, S, and T. As a result, the polymer layer thickness increased in the order of Liquid Composition S, Liquid Composition T, and Liquid Composition P. [Industrial Applicability]

[0108] As is clear from the above results, the liquid composition prepared by this method exhibited excellent dispersibility and stability, and the polymer layer obtained by applying it to a substrate exhibited excellent electrical properties and low linear expansion. Furthermore, the polymer layer and substrate exhibited excellent adhesion, and the inorganic oxide particles were firmly supported in the F layer. Therefore, laminates using the composition prepared by this method are believed to have excellent uniformity of component distribution and to highly express the properties of the inorganic oxide particles. Furthermore, no voids are formed at the layer interface, and a decrease in water resistance is believed to be suppressed. Such laminates possess electrical properties and mechanical properties such as resistance to warping and flexibility, and are therefore believed to be useful as printed circuit board materials. The entire contents of the specifications, claims and abstracts of Japanese Patent Application No. 2021-001123 filed on January 6, 2021 and Japanese Patent Application No. 2021-083690 filed on May 18, 2021 are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims

1. A method for producing a composition, comprising kneading particles of a tetrafluoroethylene-based polymer (1) having at least one of a carbonyl group-containing group and a hydroxyl group-containing group with inorganic oxide particles in the presence of water to form a mixture, and further kneading the mixture with a dispersion of polytetrafluoroethylene particles dispersed in water.

2. The tetrafluoroethylene polymer (1) has a main chain carbon number of 1×10 ６ The method according to claim 1, wherein the polymer has 10 to 5,000 carbonyl-containing groups per polymer.

3. The method according to claim 1 or 2, wherein the inorganic oxide is silicon oxide.

4. A composition comprising particles of a tetrafluoroethylene-based polymer (1) having at least one of a carbonyl group-containing group and a hydroxyl group-containing group, polytetrafluoroethylene particles, and inorganic oxide particles kneaded together, and water, wherein the average particle size of the inorganic oxide particles is in the range of 1 to 1000% of the average particle size of the particles of the tetrafluoroethylene-based polymer (1), the content of the inorganic oxide particles is 5 to 75 mass% of the total mass of the particles of the tetrafluoroethylene-based polymer (1), the polytetrafluoroethylene particles, and the inorganic oxide particles, and the dispersion rate after long-term storage, as defined below, is 60% or more. "Dispersion rate after long-term storage": When 20 mL of the composition is placed in a 30 mL vial and stored in a sealed state at 25°C for 30 days, the value is calculated using the following formula from the height of the entire composition in the vial and the height of the dispersion layer after the sealed storage. Dispersion rate (%) = (height of dispersion layer) / (height of entire composition) x 100

5. The composition of claim 4 further comprising an aromatic polymer.

6. 6. The composition of claim 4, wherein the inorganic oxide is silicon oxide.

7. The composition according to any one of claims 4 to 6, wherein the mass of the polytetrafluoroethylene relative to the total mass of the tetrafluoroethylene-based polymer (1) and the polytetrafluoroethylene is 25 mass% or more.

8. A method for producing a metal clad laminate having a metal foil and a polymer layer formed on at least one surface of the metal foil, by applying the composition described in any one of claims 4 to 7 to the surface of a metal foil and heating it, wherein the polymer layer contains a tetrafluoroethylene-based polymer (1) having at least one of a carbonyl group-containing group and a hydroxyl group-containing group, polytetrafluoroethylene and inorganic oxide particles, and the content of the inorganic oxide particles is 5 to 75 mass% relative to the total mass of the tetrafluoroethylene-based polymer (1), the polytetrafluoroethylene and the inorganic oxide particles.

9. The method for producing a metal clad laminate according to claim 8 , wherein the polymer layer further contains an aromatic polymer.

10. The method for producing a metal clad laminate according to claim 8 or 9, wherein the polymer layer has a thickness of 50 μm or more.

11. A method for producing a stretched sheet, comprising applying the composition according to any one of claims 4 to 7 to the surface of a metal foil, heating the composition to obtain a metal clad laminate having a metal foil and a polymer layer formed on at least one surface of the metal foil, and then removing the metal foil from the metal clad laminate to obtain a polymer layer which is then subjected to a stretching treatment, wherein the polymer layer contains a tetrafluoroethylene-based polymer (1) having at least one of a carbonyl group-containing group and a hydroxyl group-containing group, polytetrafluoroethylene, and inorganic oxide particles, and the content of the inorganic oxide particles is 5 to 75 mass% relative to the total mass of the tetrafluoroethylene-based polymer (1), the polytetrafluoroethylene, and the inorganic oxide particles.