Methods for producing dispersions, pastes and doughs

Abstract

Provided are: a method for producing a dispersion which includes a powder of a tetrafluoroethylene-based polymer and either an inorganic filler or a resin different from the tetrafluoroethylene-based polymer and is excellent in terms of dispersibility; a paste; and a kneaded powder.　The method for producing a dispersion comprises kneading a powder of a tetrafluoroethylene-based polymer, at least one other material selected from the group consisting of inorganic fillers and resins different from the tetrafluoroethylene-based polymer, and a liquid compound to obtain a kneaded mixture and mixing the kneaded mixture with a liquid compound to obtain the dispersion. The paste or kneaded powder is obtained by kneading a powder of a tetrafluoroethylene-based polymer and said other material.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a dispersion containing a tetrafluoroethylene polymer powder and other specified materials, and to a paste and a dough suitable for use in the production method. [Background technology]

[0002] Tetrafluoroethylene-based polymers have excellent physical properties, such as electrical insulation, water and oil repellency, chemical resistance, and heat resistance. Therefore, dispersions in which these powders are dispersed in water or oil-based solvents are useful as materials for forming resists, adhesives, electrical insulating layers, lubricants, inks, paints, etc. However, tetrafluoroethylene-based polymers have low surface energy, and the powders thereof tend to aggregate. For this reason, it is difficult to obtain low-viscosity dispersions with excellent dispersion stability. For example, Patent Document 1 discloses a non-aqueous dispersion liquid using an additive in order to improve the dispersibility of the dispersion liquid and adjust the liquid properties thereof. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 159102 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the dispersion liquid described in Patent Document 1 still does not have sufficient dispersion stability. Furthermore, a dispersion containing a tetrafluoroethylene-based polymer powder and further containing another functional material such as an inorganic filler or a resin different from the tetrafluoroethylene-based polymer may be able to impart the physical properties of the other functional material to a molded article formed from the dispersion.

[0005] However, the affinity between tetrafluoroethylene-based polymers and other functional materials is generally low, and the dispersion stability of such dispersions tends to be further reduced. Furthermore, when other functional materials are added, if high shear is applied to disperse the tetrafluoroethylene polymer powder, foaming and aggregation are likely to occur due to air entrapment and deterioration of the tetrafluoroethylene polymer. As a result, the molded product obtained from the dispersion tends to have a lower uniformity in the distribution of components and a lower water resistance due to the generation of voids.

[0006] The present inventors have investigated a method for producing a dispersion having excellent dispersion stability, which contains a tetrafluoroethylene-based polymer powder and at least one other material selected from the group consisting of an inorganic filler and a resin different from the tetrafluoroethylene-based polymer, and have completed the present invention. An object of the present invention is to provide a method for producing a dispersion containing a tetrafluoroethylene polymer powder and the other materials described above and having excellent dispersion stability, and to provide a paste and a dough suitable for use in the production method. [Means for solving the problem]

[0007] The present invention has the following aspects. [1] A method for producing a dispersion, comprising kneading a powder of a tetrafluoroethylene-based polymer, at least one other material selected from the group consisting of an inorganic filler and a resin different from the tetrafluoroethylene-based polymer, and a liquid compound to obtain a kneaded mixture, and mixing the kneaded mixture with the liquid compound to obtain a dispersion. [2] The method of [1], wherein the solid content of the kneaded product is 40% by mass or more. [3] The manufacturing method according to [1] or [2], wherein the kneaded product contains the inorganic filler, and the ratio of the powder to the inorganic filler in the kneaded product is such that the mass of the inorganic filler is 0.5 to 2 relative to the mass of the powder, where 1 is the mass of the powder. [4] The manufacturing method according to any one of [1] to [3], wherein the inorganic filler is a silica filler or a boron nitride filler. [5] The manufacturing method according to any one of [1] to [4], wherein the kneaded product contains the different resin, and the ratio of the powder to the different resin in the kneaded product is 0.01 to 0.5 by mass relative to the powder mass of 1. [6] The manufacturing method according to any one of [1] to [4], wherein the kneaded product contains the different resin, and the ratio of the powder to the different resin in the kneaded product is 1 by mass of the powder, and the ratio of the mass of the different resin is 2 to 1000. [7] The method according to any one of [1] to [6], wherein the different resin is an aromatic polymer. [8] The manufacturing method according to any one of [1] to [7], wherein the liquid compound is a low viscosity liquid or a high viscosity liquid. [9] A method for producing a dispersion, comprising kneading a powder of a tetrafluoroethylene-based polymer, a resin other than the tetrafluoroethylene-based polymer, a liquid compound, and a surfactant to obtain a kneaded mixture, and mixing the kneaded mixture with the liquid compound to obtain a dispersion.

[10] A method for producing a dispersion, comprising kneading a mixture containing a powder of a tetrafluoroethylene-based polymer and an inorganic filler with a mixture containing a resin other than the tetrafluoroethylene-based polymer and a liquid compound to obtain a kneaded mixture, and mixing the kneaded mixture with the liquid compound to obtain a dispersion.

[11] A paste having a solid content of 40% by mass or more and a viscosity of 800 to 100,000 mPa·s, obtained by kneading a powder of a tetrafluoroethylene-based polymer, at least one other material selected from the group consisting of an inorganic filler and a resin different from the tetrafluoroethylene-based polymer, and a liquid compound.

[12] The paste according to

[11] , which contains the inorganic filler, and the ratio of the powder to the inorganic filler is 0.5 to 2 by mass relative to the powder mass being 1.

[13] The paste according to

[11] or

[12] , which contains the different resin, and the ratio of the powder to the different resin is 1 by mass of the powder to 0.01 to 0.5 by mass of the different resin.

[14] A kneaded powder obtained by kneading a powder of a tetrafluoroethylene-based polymer, at least one other material selected from the group consisting of an inorganic filler and a resin different from the tetrafluoroethylene-based polymer, and a liquid compound.

[15] The dough according to

[14] , which contains the different resin, and the ratio of the powder to the different resin is 1 by mass of the powder to 0.01 to 0.5 by mass of the different resin. [Effects of the Invention]

[0008] According to the present invention, a dispersion liquid having excellent dispersion stability can be produced, which contains a tetrafluoroethylene-based polymer powder and at least one other material selected from the group consisting of an inorganic filler and a resin different from the tetrafluoroethylene-based polymer. Also, according to the present invention, a paste and a kneaded powder containing a tetrafluoroethylene-based polymer powder and other materials are provided. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following terms have the following meanings: A "tetrafluoroethylene-based polymer" is a polymer containing units based on tetrafluoroethylene, and is also simply referred to as an "F polymer." The "glass transition temperature (Tg) of a polymer" is a value measured by analyzing a polymer using dynamic mechanical analysis (DMA). 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). "D50" is the average particle size of a target substance (powders and fillers) and is the cumulative 50% diameter based on volume of the target substance determined by laser diffraction / scattering. In other words, the particle size distribution of the target substance is measured by laser diffraction / scattering, and a cumulative curve is calculated with the total volume of the target substance group as 100%. D50 is the particle size at the point on that cumulative curve where the cumulative volume is 50%. "D90" is the cumulative volume particle size of the object, and is the volume-based cumulative 90% diameter of the object that can be determined in the same manner as "D50". The "viscosity of the paste and dispersion" is a value measured for the dispersion 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 "unit based on a monomer" refers to an atomic group based on the monomer formed by polymerization of the monomer. The unit may be a unit formed directly by the polymerization reaction, or may be a unit in which a part of the unit is converted into a different structure by treating the polymer. Hereinafter, a unit based on monomer a may also be simply referred to as a "monomer a unit."

[0010] The manufacturing method of the present invention (hereinafter also referred to as this method) is a method in which a powder of F polymer (hereinafter also referred to as this powder), at least one other material (hereinafter also referred to as the other material) selected from the group consisting of an inorganic filler and a resin different from F polymer (hereinafter also referred to as the different resin) is kneaded with a liquid compound (hereinafter also referred to as liquid compound 1) to obtain a kneaded mixture (hereinafter also referred to as this kneaded mixture), and this kneaded mixture is mixed with a liquid compound (hereinafter also referred to as liquid compound 2) to obtain a dispersion (hereinafter also referred to as this dispersion). This dispersion is a dispersion in which the present powder is dispersed.

[0011] 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 fluorine content of the F polymer is preferably 70 to 76% by mass. While such F polymers with a high fluorine content have excellent electrical and other physical properties, they have low polarity, which not only reduces their affinity with other materials but also makes their powder prone to aggregation. Therefore, when a dispersion is prepared, its dispersibility is further reduced. According to this method, even in such a dispersion, the physical properties of the F polymer as a whole are not impaired, and a dispersion with excellent dispersibility can be obtained.

[0012] Since F polymer is a highly rigid polymer, it is thought that it is easily denatured in the dispersion when mixed with the dispersion medium by applying shear, which is a common method for improving dispersibility, and as a result, the dispersibility of F polymer in the dispersion medium may decrease. According to this method, it is possible to mix the liquid compound 1 and the liquid compound 2 without applying high shearing, and therefore the present dispersion can be obtained without impairing dispersibility. Furthermore, this method allows the production of this dispersion while suppressing the entrapment of air contained in this powder and other materials. As a result, dense molded products can be obtained from this dispersion, and the molded products are thought to have excellent water resistance, uniformly contain F polymer and other materials, and highly express the physical properties of both.

[0013] The melting temperature of the F polymer in the present invention 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 particularly preferably 180 to 325° C. The glass transition point of the F polymer is preferably 50° C. or higher, more preferably 75° C. or higher. The glass transition point of the F polymer is preferably 150° C. or lower, more preferably 125° C. or lower.

[0014] The F polymer is preferably polytetrafluoroethylene (hereinafter also referred to as PTFE), 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), or a copolymer containing units based on TFE and hexafluoropropylene (hereinafter also referred to as FEP), more preferably PFA or FEP, and even more preferably PFA. These polymers may further contain units based on other comonomers. As the PAVE, CF2=CFOCF3, CF2=CFOCF2CF3 or CF2=CFOCF2CF2CF3 (hereinafter also referred to as PPVE) is preferred, and PPVE is more preferred.

[0015] The F polymer preferably has an atomic group containing an oxygen atom. According to this method, the physical properties of the F polymer based on such an atomic group are not impaired, and the physical properties of the molded product obtained using this dispersion are further improved. The atomic group may be contained in a monomer unit in the F polymer or in a terminal group of the main chain of the polymer. The latter embodiment includes an F polymer having the atomic group as a terminal group derived from a polymerization initiator, a chain transfer agent, etc. The atomic group containing an oxygen atom is preferably a hydroxyl group-containing group or a carbonyl group-containing group, and particularly preferably a carbonyl group-containing group. The number of carbonyl-containing groups in the F polymer is 1 × 10 6 The number per unit is preferably 10 to 5000, more preferably 100 to 3000, and even more preferably 50 to 1500. The number of carbonyl group-containing groups in the F polymer can be quantified based on the polymer composition or the method described in WO 2020 / 145133.

[0016] The hydroxyl group-containing group is preferably a group containing an alcoholic hydroxyl group, more preferably -CF2CH2OH or -C(CF3)2OH. The carbonyl group-containing group is a group containing a carbonyl group (>C(O)), and is preferably 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.) or a carbonate group (-OC(O)O-), more preferably an acid anhydride residue.

[0017] The F polymer is preferably a polymer containing PTFE units and PAVE units, with 1.5 to 5.0 mol% of PAVE units relative to all units, and with a melting temperature of 280 to 320°C. More preferred is F polymer (1) containing TFE units and PAVE units and having an atomic group containing an oxygen atom, or F polymer (2) containing TFE units and PAVE units, with 2 to 5 mol% of PAVE units relative to all monomer units, and having no atomic group containing an oxygen atom. These polymers form microspherulites in molded articles, which tends to improve the properties of the molded articles.

[0018] The polymer (1) is preferably a polymer containing TFE units, PAVE units, and units derived from a monomer having a hydroxyl group-containing group or a carbonyl group-containing group. The polymer (1) preferably contains 90 to 98 mol% TFE units, 1.5 to 9.97 mol% PAVE units, and 0.01 to 3 mol% units derived from the above monomers, based on the total units. The monomer is preferably itaconic anhydride, citraconic anhydride, or 5-norbornene-2,3-dicarboxylic anhydride (also known as himic anhydride; hereinafter, also referred to as "NAH"). Specific examples of F polymer (1) include the polymers described in WO 2018 / 16644.

[0019] The F polymer (2) is composed of only TFE units and PAVE units, and preferably contains 95 to 98 mol % of TFE units and 2 to 5 mol % of PAVE units based on the total monomer units. The content of PAVE units in the F polymer (2) is preferably 2.1 mol % or more, more preferably 2.2 mol % or more, based on the total monomer units. The term "F polymer (2) does not have an atomic group containing an oxygen atom" means that the number of carbon atoms constituting the polymer main chain is 1 × 10 6 This means that the number of atomic groups containing oxygen atoms in the polymer per unit is less than 500. The number of atomic groups containing oxygen atoms is preferably 100 or less, and more preferably less than 50. The lower limit of the number of atomic groups containing oxygen atoms is usually 0.

[0020] The F polymer (2) may be produced using a polymerization initiator or a chain transfer agent that does not generate an atomic group containing an oxygen atom as a terminal group of the polymer chain, or may be produced by fluorinating an F polymer having an atomic group containing an oxygen atom. Fluorination methods include methods using fluorine gas (see, for example, JP 2019-194314 A).

[0021] The present powder in the present invention is a powder containing an F polymer, and the amount of the F polymer in the present powder is preferably 80% by mass or more, and more preferably 100% by mass. The D50 of the present powder is preferably 20 μm or less, more preferably 8 μm or less. The D50 of the present powder is preferably 0.1 μm or more, more preferably 0.3 μm or more. Furthermore, the D90 of the present powder is more preferably 50 μm or less. If the D50 and D90 of the present powder are within these ranges, the surface area of ​​the present powder is increased, and the dispersibility of the present powder is likely to be further improved.

[0022] The powder may contain other resins or inorganic substances different from the F polymer. Specific examples of other resins include aromatic polymers, such as aromatic polyimides, aromatic polyamideimides, aromatic maleimides, aromatic elastomers such as styrene elastomers, and aromatic polyamic acids. A specific example of the inorganic material is silica. The present powder containing other resins or inorganic substances preferably has a core-shell structure with the F polymer as the core and the other resins or inorganic substances as the shell. Such a present powder can be obtained, for example, by coalescence (collision, aggregation, etc.) of the F polymer powder with the other resins or inorganic substances.

[0023] The other material in the present invention may be only an inorganic filler, may be only the different resin, or may be both an inorganic filler and the different resin. A preferred embodiment of the inorganic filler will be described in detail in the later-described Method (1), and a preferred embodiment of the different resin will be described in detail in the later-described Method (2).

[0024] The liquid compound 1 in the present invention is a liquid that has the function of dissolving, dispersing, or gelling the present powder and other materials, and when the present powder and other materials are combined with the liquid compound to form a composition, the composition is usually a liquid composition, specifically a slurry or gel composition. In the present invention, the liquid compound 1 used for kneading and the liquid compound 2 mixed with this kneaded product to obtain a dispersion may be the same or different. It is preferable that both are the same.

[0025] Liquid compounds 1 and 2 may be used singly or in combination of two or more. Liquid compounds 1 and 2 are preferably degassed to prevent deterioration of the uniformity of the component distribution in the molded product and suppress voids. The liquid compounds 1 and 2 are preferably low viscosity liquids or high viscosity liquids.

[0026] The low viscosity liquid is preferably a liquid compound having a viscosity of more than 0 mPa·s and not more than 10 mPa·s at 25°C, and is a liquid compound that does not react with the F polymer and other resins. The boiling point of the low viscosity liquid is preferably 75° C. or higher, more preferably 100° C. or higher, and is preferably 300° C. or lower, more preferably 250° C. or lower. The low viscosity liquid may be water or a non-aqueous dispersion medium, preferably an amide, a ketone, or an ester.

[0027] Examples of ketones include acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl n-pentyl ketone, methyl isopentyl ketone, 2-heptanone, cyclopentanone, cyclohexanone, and cycloheptanone. Examples of the ester include methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethyl 3-ethoxypropionate, γ-butyrolactone, and γ-valerolactone.

[0028] Examples of the amide include 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, and 1,3-dimethyl-2-imidazolidinone. Specific examples of suitable low viscosity liquids include water, N-methyl-2-pyrrolidone, γ-butyrolactone, cyclohexanone, and cyclopentanone.

[0029] The highly viscous liquid is preferably a liquid compound having a viscosity of more than 10 mPa·s at 25°C, and is preferably a liquid compound that does not react with the F polymer and other resins. The viscosity of the highly viscous liquid is preferably 200 mPa·s or less. The boiling point of the highly viscous liquid is preferably 100°C or more. The boiling point of the highly viscous liquid is preferably 350°C or less, and more preferably 300°C or less. The highly viscous liquid is preferably a glycol, glycol ether or glycol acetate, more preferably a glycol monoalkyl ether, glycol monoaryl ether, glycol monoalkyl ether acetate or glycol monoaryl ether acetate, and even more preferably a glycol monoalkyl ether.

[0030] Specific examples of highly viscous liquids include ethylene glycol mono-2-ethylhexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monobutyl ether, triethylene glycol monomethyl ether, tripropylene glycol monobutyl ether, propylene glycol monophenyl ether, diethylene glycol monoethyl ether acetate, and diethylene glycol monobutyl ether acetate.

[0031] In the present invention, the present powder, other materials and liquid compound 1 are kneaded to obtain the present kneaded product. During kneading, it is preferable to knead the present powder, other materials, and liquid compound 1 so that the total mass does not change substantially, and it is preferable to knead in a closed system. That is, it is preferable to knead the present powder, other materials, and liquid compound 1 so that liquid compound 1 does not evaporate during kneading. As a result, each component is kneaded uniformly, and a highly defoamed present kneaded product is obtained. For kneading, it is preferable to use a kneader equipped with a stirring tank and single- or multiple-shaft stirring blades. The number of stirring blades is preferably two or more to obtain a high kneading effect. The kneading method may be either batch or continuous.

[0032] The kneading machine used for batch mixing is preferably a Henschel mixer, pressure kneader, Banbury mixer, or planetary mixer, with a planetary mixer being more preferred. A planetary mixer has two agitating blades that rotate and revolve around each other, and is designed to agitate and knead the mixture in the mixing vessel. This reduces the dead space in the mixing vessel where the agitating blades do not reach, reducing the load on the blades and enabling advanced mixing. In other words, while suppressing aggregation of the F polymer, the F powder can be wetted with the liquid compound, allowing the F powder and other materials to interact with each other to a high degree while being mixed. Furthermore, after mixing is complete, the dispersion medium can be added directly to the resulting kneaded mixture to produce the dispersion. That is, the kneading in this method is preferably carried out in a stirring vessel having two stirring blades that rotate and revolve around each other.

[0033] Furthermore, when the powder, other materials, and liquid compound 1 are heated to a predetermined temperature and kneaded, the F polymer becomes viscous, placing a load on the mixing blades of the mixer, which tends to increase the shear force on the F polymer. In particular, when multiple mixing blades are used, shear force is likely to be applied to the F polymer between the mixing blades or between the mixing blades and the mixing vessel. As a result, when the other material is an inorganic filler, not only are the powder and the inorganic filler thoroughly mixed, but the powder or inorganic filler is also pulverized, making it easier to form a dense mixture. Furthermore, when the other material is a different resin, a mixture is formed that can be considered a composite in which the powder and the different resin highly interact, making it easier to form a dense mixture.

[0034] The end point of the kneading can be determined by the change in the current consumption when monitored, since the load on the stirring blades decreases as the kneading progresses and the current consumption of the kneader decreases. Alternatively, the kneading may be controlled by dividing the load current of the kneader by the shear rate of the kneader and using this value as the force and energy applied to the kneaded material or composition. Specifically, it is preferable to increase the load current from the start of kneading and then gradually decrease it.

[0035] Examples of continuous kneaders include twin-screw extrusion kneaders and millstone kneaders. A twin-screw extrusion kneader is, for example, a twin-screw type continuous kneading device that kneads a material or composition by the shear force between two screws that are arranged parallel and close to each other. A millstone-type kneader is, for example, a kneader having a cylindrical fixed part with an internal space through which the kneaded material or composition can pass, and a rotating part that is arranged in the internal space of the fixed part and rotates to continuously knead the kneaded material passing through the internal space while conveying it in the direction of the rotation axis.

[0036] Examples of the kneading method include a method in which the present powder, other materials, and liquid compound 1 are kneaded all at once, a method in which these are mixed to form a composition and then kneaded, a method in which the present powder and other materials are added sequentially to liquid compound 1 while kneading, and a method in which the present powder and other materials are added sequentially to liquid compound 1 and then kneaded together.Other methods include a method in which a mixture of the present powder and other materials is prepared in advance and then kneaded with liquid compound 1, and a method in which a composition of the present powder and liquid compound 1 and a composition of the other materials and liquid compound 1 are prepared separately, and then the two compositions are mixed and kneaded. Among these methods, a method in which the present powder, other materials and liquid compound 1 are mixed to form a composition, and the resulting composition is kneaded is preferred, and it is more preferred that the composition is a liquid composition.

[0037] The kneaded product obtained as described above has high viscosity and is usually a semi-solid or solid kneaded product, preferably a paste or a dough. In this specification, the term "paste" refers to a kneaded product having fluidity and viscosity, and the term "dough" refers to a lump-like or clay-like kneaded product.

[0038] The viscosity of the present kneaded product (hereinafter also referred to as the present paste) in the form of a paste is preferably 800 mPa·s or more, more preferably 1000 mPa·s or more, and even more preferably 10000 mPa·s or more. The viscosity of the present paste is preferably 100,000 mPa·s or less, and more preferably 80,000 mPa·s or less. The viscosity of the present paste is preferably 800 to 100,000 mPa·s, and more preferably 1000 to 100,000 mPa·s.

[0039] A preferred embodiment of the paste is a paste containing the powder, other materials, and a liquid compound, with a solid content of 40% by mass or more and a viscosity of 800 to 100,000 mPa·s.

[0040] In the present paste containing an inorganic filler, the ratio of the present powder to the inorganic filler, where the mass of the present powder is 1, is preferably 0.5 to 2, more preferably 0.6 to 1.5, and even more preferably 0.7 to 1. In such a case, the present paste tends to have excellent dispersion stability.

[0041] In the paste containing the different resin, the mass ratio of the powder to the different resin is preferably 0.01 to 0.5 or 2 to 1000, where the mass of the powder is 1. In this case, the paste is likely to have excellent dispersibility, and the resulting dispersion is likely to have excellent dispersion stability. That is, when the ratio is in the former range, a component that can be considered a composite in which the powder is coated with the different resin is formed, and the dispersibility of the paste is likely to be improved. On the other hand, when the ratio is in the latter range, the powder is highly dispersed in the different resin, and the dispersibility of the paste is likely to be improved. The ratio in the former range is more preferably 0.05 to 0.2, and even more preferably 0.08 to 0.1, and the ratio in the latter range is more preferably 3 to 500, and even more preferably 5 to 100. In this case, the paste and the resulting dispersion liquid tend to have excellent dispersion stability even when they do not contain a surfactant.

[0042] The solid content of the paste refers to the total amount of substances that form solids in a molded product formed from the paste or dispersion. For example, if the paste contains the F polymer and an inorganic filler and / or a different resin (described later), the total content of these components is the solid content of the paste. The solid content of the paste is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more. The solid content is preferably 90% by mass or less, more preferably 80% by mass or less. In this case, the dispersion liquid having excellent dispersion stability can be easily obtained from the paste.

[0043] In the paste, the content of the powder in the solid content is preferably 25% by mass or more, more preferably 30% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less. In the paste containing an inorganic filler, the content of the inorganic filler in the solid content is preferably 10% by mass or more, more preferably 25% by mass or more, and is preferably 75% by mass or less, more preferably 60% by mass or less. In the paste containing the different resin, the content of the different resin in the solid content is preferably 1% by mass or more, more preferably 5% by mass or more, and is preferably 20% by mass or less, more preferably 10% by mass or less. In the present paste containing both an inorganic filler and the present different resin, it is preferable that at least one of the inorganic filler or the present different resin is within the above range, and more preferably both are within the above range. For example, the total amount of the present powder, inorganic filler, and present different resin in the solid content is preferably 25% by mass or more of the present powder, 25% by mass or more of the inorganic filler, or 1% by mass or more of the present different resin, assuming the solid content to be 100% by mass; more preferably 25% by mass or more of the present powder, 25% by mass or more of the inorganic filler, and 1% by mass or more of the present different resin, assuming the solid content to be 100% by mass. For example, the ratio of the present powder to the inorganic filler and the present different resin is preferably such that the mass of the present powder is 1, and the mass of the inorganic filler is 0.5 to 2, or the mass of the present different resin is 0.01 to 0.5, and more preferably the mass of the present powder is 1, and the mass of the inorganic filler is 0.5 to 2, and the mass of the present different resin is 0.01 to 0.5.

[0044] The solid content of the paste refers to the total amount of substances that form the solid content in a molded product formed from the paste or dispersion. For example, if the paste contains the F polymer and an inorganic filler and / or a different resin (described later), the total content of these components is the solid content of the paste. The content of liquid compound 1 in the paste is preferably 50% by mass or less, more preferably 40% by mass or less. The content of liquid compound 1 in the dough is preferably 20% by mass or more, more preferably 25% by mass or more.

[0045] The solid content of the present kneaded product (hereinafter also referred to as the present kneaded powder) is preferably more than 50% by mass, more preferably 60% by mass or more. The solid content is preferably 99% by mass or less, more preferably 95% by mass or less. In this case, the present kneaded powder tends to have excellent dispersibility, and the resulting present dispersion tends to have excellent dispersion stability. The solid content of the present kneaded powder means the total amount of substances that form the solid content in the molded product formed from the present kneaded powder or the present dispersion. For example, if the present kneaded powder contains F polymer and an inorganic filler and / or a different resin (described below), the total content of these components is the solid content of the present kneaded powder. When the present dough contains an inorganic filler, the ratio of the present powder to the inorganic filler is preferably 0.5 to 2, more preferably 0.6 to 1.5, and even more preferably 0.7 to 1, with the mass of the present powder being 1.

[0046] When the present dough contains the different resin, the ratio of the present powder to the different resin is preferably 0.01 to 0.5 or 2 to 1000, with the mass of the present powder being 1. In this case, the present dough tends to have excellent dispersibility, and the resulting present dispersion tends to have excellent dispersion stability. That is, when the above ratio is in the former range, a component that can be considered a composite in which the present powder is coated with the different resin is formed, and the dispersibility of the dough tends to be improved. On the other hand, when the above ratio is in the latter range, the present powder is highly dispersed in the different resin, and the dispersibility of the dough tends to be improved. The ratio in the former range is more preferably 0.05 to 0.2, and even more preferably 0.08 to 0.1. The ratio in the latter range is more preferably 3 to 500, and even more preferably 5 to 100. In this case, the present batter and the resulting present dispersion tend to have excellent dispersion stability even when they do not contain a surfactant. When the dough contains both an inorganic filler and the different resin, it is preferred that at least one of the inorganic filler or the different resin is within the above range, and more preferred that both are within the above range. For example, the ratio of the present powder to the inorganic filler and the present different resin is preferably such that the mass of the present powder is 1, and the mass of the inorganic filler is 0.5 to 2, or the mass of the present different resin is either 0.001 to 0.5, or 2 to 1000; more preferably, the mass of the present powder is 1, and the mass of the inorganic filler is 0.5 to 2, and the mass of the present different resin is 0.001 to 0.5, or 2 to 1000.

[0047] In the present knead containing inorganic filler and / or different resin, the content of the present powder in the solid content is preferably 25% by mass or more, more preferably 30% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less. In the present kneaded powder, the content of the inorganic filler relative to the solid content is preferably 10% by mass or more, more preferably 25% by mass or more, and is preferably 75% by mass or less, more preferably 60% by mass or less. In the present kneaded powder, the content of the present different resin in the solid content is preferably 1% by mass or more, more preferably 5% by mass or more, and preferably 50% by mass or less, more preferably 20% by mass or less. When the dough contains both an inorganic filler and the different resin, it is preferred that at least one of the inorganic filler or the different resin is within the above range, and more preferred that both are within the above range. When the present dough contains both an inorganic filler and the present different resin, the total amount of the present powder, the inorganic filler, and the present different resin in the solid content is preferably 25% by mass or more of the present powder, and either 10% by mass or more of the inorganic filler or 1% by mass or more of the present different resin, assuming the solid content to be 100% by mass; more preferably 25% by mass or more of the present powder, 10% by mass or more of the inorganic filler, and 1% by mass or more of the present different resin, assuming the solid content to be 100% by mass.

[0048] The content of liquid compound 1 in the dough is preferably 50% by mass or less, more preferably 40% by mass or less, and preferably 20% by mass or more, more preferably 25% by mass or more. The present dough preferably has a viscosity of 10,000 to 100,000 Pa·s when measured with a capillograph (temperature: 25°C, shear rate: 1 / sec, capillary length: 10 mm, capillary radius: 1 mm, furnace diameter: 9.55 mm, load cell capacity: 2 t). In particular, when the viscosity of the present dough having a solid content of 60 to 70 mass% is in this range, the dispersibility when mixed with liquid compound 2 and the dispersion stability of the resulting dispersion are particularly likely to be improved. The present dough having such a viscosity can be produced by controlling the kneading time and shear force during kneading; specifically, it can be produced by extending the kneading time and increasing the shear force.

[0049] If the present kneaded product is mixed with the liquid compound 2, the present dispersion is obtained, and if the present paste or the present kneaded powder is mixed with the liquid compound 2 as the present kneaded product, the present dispersion can be obtained more efficiently. In the present invention, the kneaded product and liquid compound 2 are preferably mixed using 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, from the viewpoint of dispersibility and dispersion stability of the resulting dispersion. It is more preferable to use a media-using disperser.

[0050] In addition, mixing using an impact disperser improves the dispersion stability of the present dispersion, so it is preferable to use an impact disperser, which is a disperser that causes pressurized liquid compound 2 to collide with the present paste, thereby dispersing the paste by the impact force or the like. The dispersing machine may be either a dispersing machine that pressurizes the present paste and the liquid compound 2 and causes them to collide, or a dispersing machine that causes the pressurized liquid compound 2 to collide with the present paste. The former type of dispersing machine includes Nanomizer, Genus PY, Ultimizer, and Aqua. Examples of the latter dispersing machine include a homogenizer.

[0051] Further, examples of the method for mixing the present kneaded product with the liquid compound 2 include a method in which, following the kneading for preparing the present kneaded product, the present kneaded product is mixed with the liquid compound 2 in a kneader having a stirring tank and stirring blades used for kneading, and a method in which the present kneaded product is removed from the kneader used for kneading and mixed with the liquid compound 2 in another kneader. Examples of the kneader include batch and continuous kneaders similar to those mentioned above.

[0052] The viscosity of the dispersion 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 dispersion 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 thixotropy ratio of the present dispersion is preferably 1 to 10, more preferably 1 to 7. The present dispersion having such a thixotropy ratio has excellent coatability and uniformity. The thixotropy ratio is calculated by dividing the viscosity of the present dispersion measured at a rotation speed of 30 rpm by the viscosity of the present dispersion measured at a rotation speed of 60 rpm.

[0053] From the viewpoint of preventing a decrease in uniformity of component distribution and voids in the molded article obtained from the dispersion, the foam volume ratio in the dispersion 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 dispersion liquid (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

[0054] A first preferred embodiment of the present invention (hereinafter also referred to as the present method (1)) includes a method in which the present powder, inorganic filler, and liquid compound 1 are kneaded to obtain the present kneaded product (hereinafter also referred to as the present kneaded product 1), and the present kneaded product 1 is mixed with liquid compound 2 to obtain the present dispersion (hereinafter also referred to as the present dispersion 1). Examples of the kneading method include a method in which the present powder, inorganic filler, and liquid compound 1 are kneaded all at once, a method in which they are mixed to form a composition and then kneaded, a method in which the present powder and inorganic filler are added sequentially to liquid compound 1 while being kneaded, and a method in which the present powder and inorganic filler are added sequentially to liquid compound 1 and then kneaded together.Other methods include a method in which a mixture of the present powder and inorganic filler is prepared in advance and then kneaded with liquid compound 1, and a method in which a composition of the present powder and liquid compound 1 and a composition of the inorganic filler and liquid compound 1 are prepared separately, and then the two compositions are mixed and kneaded. The composition in the present method (1) is preferably a liquid composition. The present kneaded product 1 in the present method (1) may be a paste (hereinafter also referred to as the present paste 1) or a dough (hereinafter also referred to as the present dough 1). Among these methods, a method in which the present powder, inorganic filler, and liquid compound 1 are mixed to form a composition, the obtained composition is kneaded to obtain the present kneaded product 1, and the present kneaded product 1 and liquid compound 2 are mixed to obtain the present dispersion liquid 1 is preferred.

[0055] The inorganic filler in Method (1) is used to improve the physical properties of the resulting molded product when Dispersion 1 is used to form various molded products, and the type of filler is appropriately selected depending on the purpose of the molded product. For example, when the purpose is to improve the dielectric constant of a molded product, a high-dielectric-constant inorganic filler is used. A high-dielectric-constant inorganic filler means a filler having a dielectric constant at 25°C of 10 or more, preferably 25 or more, and more preferably 50 or more. Such inorganic filler is preferably a perovskite-type ferroelectric filler or a bismuth-layered perovskite-type ferroelectric filler. 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.

[0056] For example, when the dielectric constant and dielectric loss tangent or linear expansion coefficient of a molded product is to be reduced, an inorganic filler having a low dielectric constant and dielectric loss tangent or a low linear expansion coefficient is used. Such inorganic fillers are preferably boron nitride fillers, beryllium oxide fillers (beryllia fillers), silicon oxide fillers (silica fillers), wollastonite fillers, or magnesium metasilicate fillers (steatite fillers).

[0057] For example, when the thermal conductivity or scratch resistance of a molded product is to be improved, a metal oxide filler is used. The metal oxide is preferably at least one selected from the group consisting of aluminum oxide, lead oxide, iron oxide, tin oxide, magnesium oxide, titanium oxide, zinc oxide, antimony pentoxide, zirconium oxide, lanthanum oxide, neodymium oxide, cerium oxide, and niobium oxide, and aluminum oxide is more preferred. These metal oxides (particularly aluminum oxide) are also preferred in terms of their high thermal conductivity and Mohs hardness.

[0058] In addition, other inorganic fillers such as glass fiber filler and carbon filler may also be used. Examples of the carbon filler include carbon fillers containing at least one selected from the group consisting of carbon fiber, carbon black, graphene, graphene oxide, fullerene, graphite, and graphite oxide. Examples of the carbon fiber include polyacrylonitrile-based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, and carbon nanotubes (single-wall, double-wall, multi-wall, cup-laminated, etc.).

[0059] From the viewpoint of dispersibility of the present dispersion 1, the inorganic filler is preferably a boron nitride filler, a silica filler, or a magnesium metasilicate filler, more preferably a silica filler or a boron nitride filler, and even more preferably a silica filler. These fillers may also be fired ceramic fillers. The inorganic filler is preferably a filler containing silicon oxide or magnesium metasilicate. The content of silicon oxide or magnesium metasilicate in this inorganic filler is preferably 50% by mass or more, more preferably 75% by mass. The content of silicon oxide or magnesium metasilicate is preferably 100% by mass or less, more preferably 90% by mass or less.

[0060] The shape of the inorganic filler is appropriately selected depending on the purpose, and may be particulate or fibrous. If a particulate filler is used, the surface flatness of the molded product is improved, the surface sliding property is improved, and the scratch resistance is likely to be improved. On the other hand, if a fibrous inorganic filler is used, part of the filler particles are exposed on the surface of the molded product, and for example, the wear resistance and scratch resistance of the product surface are likely to be improved. Specific shapes of the inorganic filler include spherical, scale-like, layer-like, leaf-like, apricot-like, columnar, cockscomb-like, equiaxed, leaf-like, micaceous, block-like, flat, wedge-like, rosette-like, net-like, and prismatic shapes, with spherical or scale-like shapes being preferred. In the case of a particulate inorganic filler, its average particle diameter D50 is preferably 0.02 to 200 μm, more preferably 0.1 to 20 μm, and even more preferably 1 to 10 μm. In the case of a fibrous inorganic filler, its average fiber length is preferably 0.05 to 300 μm. The average fiber diameter of the fibrous inorganic filler is preferably 0.01 to 15 μm.

[0061] In addition, the inorganic filler may have various shapes such as a hollow shape or a honeycomb shape in addition to the above shapes, but it is preferable that the inorganic filler have a hollow shape from the viewpoint of improving the low dielectric constant and low dielectric loss tangent of the molded product. The hollow ratio, which is the average volume ratio of voids per particle of the hollow inorganic filler, is preferably 40 to 80%. The particle strength of the hollow inorganic filler is preferably 20 MPa or more. The particle strength is the particle strength when the remaining rate of the hollow inorganic filler after pressure pressing is 50%. The particle strength can be calculated from the apparent density of the hollow inorganic filler and the apparent density of the pellet obtained by pressure pressing the medium-spherical inorganic filler.

[0062] The inorganic filler is preferably at least partially surface-treated. Examples of surface treatment agents used for such 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 alkanolamines, trimethylamine, and triethylamine, paraffin wax, silane coupling agents, silicones, and polysiloxanes.

[0063] The inorganic filler is preferably an inorganic filler that has been surface-treated with a silane coupling agent. Such inorganic fillers have excellent affinity with the present powder and tend to improve the dispersibility of the present dispersion. Furthermore, when the F polymer is melted and sintered to form a molded product from the present dispersion containing the inorganic filler, the inorganic filler is thermally decomposed to generate gas, which is thought to promote the flow of the inorganic filler and tend to improve the uniformity of the molded product. The silane coupling agent is preferably a silane coupling agent having a functional group, and more preferably 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, or 3-isocyanatopropyltriethoxysilane.

[0064] The inorganic filler may be one type of inorganic filler used alone or two or more types of inorganic fillers may be used in combination. In the latter case, it is preferable to use at least a silica filler, and more preferable to use two types of silica fillers. In addition, in the latter case, it is preferable to use a hollow inorganic filler and a non-hollow inorganic filler in combination.

[0065] Specific examples of suitable inorganic fillers include silica fillers (such as the "Admafine (registered trademark)" series manufactured by Admatechs Co., Ltd.), zinc oxide 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 (such as the "SFP (registered trademark)" series manufactured by Denka Co., Ltd.), titanium oxide coated with a polyhydric alcohol and an inorganic substance (such as the "Tipaque (registered trademark)" series manufactured by Ishihara Sangyo Kaisha, Ltd.), and rutile-type titanium oxide surface-treated with alkylsilane (such as the "Teikai (registered trademark)" series manufactured by Teika Co., Ltd.). "JMT (registered trademark)" series, etc.), hollow silica filler ("E-SPHERES" series manufactured by Taiheiyo Cement Corporation, "Silinax" series manufactured by Nittetsu Mining Co., Ltd., "Ecocospher" series manufactured by Emerson & Cumming Co., Ltd., etc.), talc filler ("SG" series manufactured by Nippon Talc Co., Ltd., etc.), steatite filler ("BST" series manufactured by Nippon Talc Co., Ltd., etc.), boron nitride filler ("UHP" series manufactured by Showa Denko KK, "Denka Boron Nitride" series ("GP", "HGP" grades), etc. manufactured by Denka Co., Ltd.).

[0066] In the present method (1), the content of the liquid compound 1 in the present kneaded product 1 is preferably 10% by mass or more. The content of the liquid compound 1 is preferably 60% by mass or less, more preferably 25% by mass or less. In this case, the present powder is always kept in a wet state while kneading proceeds, and the present powder, inorganic filler, and liquid compound 1 are uniformly mixed, making it easy to obtain a highly degassed present kneaded product 1.

[0067] The solid content of the present kneaded product 1 contains the present powder and an inorganic filler. The solid content of the present kneaded product 1 also includes substances other than the present powder and inorganic filler that form solid content in a molded product formed from the present dispersion 1. When the present kneaded product 1 is the present paste 1, the solid content is preferably 40% by mass or more, and more preferably 50% by mass or more, where the total mass of the present paste 1 is 100% by mass, from the viewpoint of easily obtaining the present paste 1 with excellent dispersibility by kneading. Also, from the viewpoint of the dispersibility of the present dispersion 1, the solid content is preferably 90% by mass or less, and more preferably 75% by mass or less. The solid content may contain non-volatile components other than the present powder and inorganic filler, and the total amount of the present powder and inorganic filler 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 being 100% by mass. The total amount is preferably 100% by mass or less.

[0068] In the present method (1), the ratio of the present powder to the inorganic filler in the present kneaded product 1 is preferably such that the mass of the present powder is 1 to the mass of the inorganic filler in the range of 0.5 to 2. The amount of the present powder in the solid content is preferably 25% by mass or more, more preferably 30% by mass or more, based on 100% by mass of the solid content, and is preferably 50% by mass or less, more preferably 40% by mass or less. Apart from the above ratio, the amount of inorganic filler in the solid content of the kneaded product 1 is preferably 25% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, based on 100% by mass of the solid content, from the viewpoint of the electrical properties of the molded product molded from the dispersion liquid 1. The amount of inorganic filler is preferably 75% by mass or less, more preferably 60% by mass or less.

[0069] In the present method (1), when the present kneaded product 1 is obtained by kneading the composition 1, the composition 1 can be prepared by mixing the present powder, an inorganic filler, and the liquid compound 1. The mixing method may include a method in which the present powder, inorganic filler, and liquid compound 1 are mixed all at once, and a method in which the present powder, inorganic filler, and liquid compound 1 are mixed while being added in sequence. Specific mixing methods include, for example, a method in which the present powder and inorganic filler are added to liquid compound 1 all at once and mixed; a method in which the present powder and inorganic filler are added to liquid compound 1 sequentially while mixing; a method in which the present powder and inorganic filler are mixed in advance and the resulting mixture is mixed with liquid compound 1; a method in which the present powder and liquid compound 1 are mixed in advance, and then an inorganic filler and liquid compound 1 are mixed in advance, and then the resulting two mixtures are further mixed; Among these methods, from the viewpoint of dispersibility of the composition 1, a method in which the present powder and an inorganic filler are mixed in advance, and the obtained mixture is mixed with the liquid compound 1 is preferred.

[0070] The kneaded product 1 in the present method (1) may contain components other than the present powder, inorganic filler, and liquid compound 1. Such components may be components that form solid content in a molded product formed from the present dispersion 1, or may be components that do not form solid content. Such components include resins different from the F polymer. Examples of the different resin include resins similar to the present different resin in the present method (2) described below, and aromatic polymers are preferred from the viewpoint of improving the adhesiveness and low linear expansion of the molded product. When such a component is a component that forms a solid content, the amount of such a component contained in the solid content of the present kneaded product 1 is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0071] The aromatic polymer is preferably an aromatic polyimide, an aromatic maleimide, an aromatic elastomer such as a styrene-based elastomer, or an aromatic polyamic acid, more preferably an aromatic polyimide, an aromatic maleimide, a polyphenylene ether, or an aromatic elastomer such as a styrene-based elastomer, and even more preferably an aromatic polyimide or an aromatic polyamic acid. The aromatic polyimide may be thermoplastic or thermosetting. A thermoplastic polyimide refers to a polyimide in which imidization is complete and no further imidization reaction occurs. When the kneaded product 1 in the method (1) contains a different resin, the kneaded product 1 is preferably obtained by mixing the powder with an inorganic filler, mixing the resulting mixture with the liquid compound 1 and the different resin to prepare a composition 1, and kneading the composition 1.

[0072] In the present method (1), it is preferable to knead the composition 1 to obtain the present kneaded product 1. In the present method (1), the present kneaded product 1 is preferably the present paste 1 or the present dough 1. In order to improve the dispersion stability and handleability of the dispersion, the kneaded product 1 in the method (1) preferably contains a surfactant. The surfactant-containing paste may be prepared by kneading the powder, inorganic filler, liquid compound 1, and surfactant all at once, or by kneading a surfactant-containing composition 1, or by kneading a surfactant-free composition 1, and then adding and kneading the resulting mixture.

[0073] The surfactant may be anionic, cationic or nonionic, with nonionic surfactants being preferred. The hydrophilic portion of the surfactant preferably has an oxyalkylene group or an alcoholic hydroxyl group. The oxyalkylene group may be composed of one type or two or more types, and in the latter case, the different types of oxyalkylene groups may be arranged randomly or in blocks. The oxyalkylene group is preferably an oxyethylene group.

[0074] 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 an acetylene-based surfactant, a silicone-based surfactant, or a fluorine-based surfactant, and more preferably a silicone-based surfactant. As the fluorosurfactant, a fluorosurfactant having a hydroxyl group, particularly an alcoholic hydroxyl group, or an oxyalkylene group and a perfluoroalkyl group or a perfluoroalkenyl group is preferred.

[0075] 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 KK), and "KF-6011" and "KF-6043" (manufactured by Shin-Etsu Chemical Co., Ltd.). When the present kneaded product 1 contains a surfactant, the content thereof in the present kneaded product 1 is preferably 1 to 15 mass %. In this case, the affinity between the components increases, and the dispersion stability of the present dispersion liquid 1 is more likely to be improved.

[0076] A second preferred embodiment of the present method (hereinafter also referred to as the present method (2)) is an embodiment in which the present powder, the present resin, and liquid compound 1 are kneaded to obtain a kneaded product (hereinafter also referred to as the present kneaded product 2), and the present kneaded product 2 and liquid compound 2 are mixed to obtain a dispersion (hereinafter also referred to as the present dispersion 2). Methods for obtaining the present kneaded product 2 include, for example, a method of kneading the present powder, the present different resin, and liquid compound 1 all at once, a method of mixing them to form a composition and kneading the resulting composition, a method of kneading while sequentially adding the present powder and the present different resin to liquid compound 1, and a method of adding the present powder and an inorganic filler sequentially to liquid compound 1 and finally kneading them.Other methods include a method of preparing a masterbatch of the present powder and the present different resin in advance and kneading it with liquid compound 1, and a method of preparing a composition of the present powder and liquid compound 1 and a composition of the present different resin and liquid compound 1 separately, and mixing and kneading the two compositions. The composition in the present method (2) is preferably a liquid composition. The present kneaded product 2 in the present method (2) may be a paste (hereinafter also referred to as the present paste 2) or a dough (hereinafter also referred to as the present dough 2). Among these methods, a preferred method is to mix the present powder, the present different resin, and liquid compound 1 to form a composition (hereinafter also referred to as composition 2), knead the obtained composition 2 to obtain the present kneaded product 2, and then mix the present kneaded product 2 with liquid compound 2 to obtain the present dispersion liquid 2.

[0077] The different resin in method (2) is a resin different from the F polymer and is a polymer that does not contain a TFE unit. The different resin may be a thermosetting resin or a thermoplastic resin. The different resins include aromatic polyesters, aromatic polyimides, aromatic polyamic acids, aromatic polyamideimides, epoxy resins, maleimide resins, urethane resins, thermoplastic elastomers, non-aromatic polyamideimides, polyphenylene ethers, polyphenylene oxides, liquid crystal polyesters, polysaccharides, nylons, acrylic resins, methacrylic resins, butyral, cyanate ester resins, ABR rubber, cellulose, PVA acrylic methacrylic Examples of the fluoropolymer include fluoropolymers other than fluorocarbon polymers, polyalkylene ethers, polyoxyethylene alkyl ethers, and F polymers.

[0078] The different resin is preferably an aromatic polyester, an aromatic polyimide, an aromatic polyamic acid, an aromatic polyamideimide, a polyphenylene ether, an epoxy resin, a maleimide resin, or a thermoplastic elastomer. The aromatic polyimide may be thermoplastic or thermosetting. The different resin is preferably an aromatic polymer. Specific examples of aromatic polyimides include the "Neoprim (registered trademark)" series (manufactured by Mitsubishi Gas Chemical Company, Inc.), the "Spixeria (registered trademark)" series (manufactured by Somar), the "Q-PILON (registered trademark)" series (manufactured by PI Technical Research Institute), the "WINGO" series (manufactured by Wingo Technology Co., Ltd.), the "Tomide (registered trademark)" series (manufactured by T&K TOKA Corporation), the "KPI-MX" series (manufactured by Kawamura Sangyo Co., Ltd.), and the "UPIA (registered trademark)-AT" series (manufactured by Ube Industries, Ltd.). Specific examples of aromatic polyamideimides include "HPC-1000" and "HPC-2100D" (manufactured by Showa Denko Materials Co., Ltd.).

[0079] The urethane resin may be, for example, urethane fine particles containing an acrylic component, or may be a homopolymer or copolymer. Specific examples include commercially available Dimic Beads CM (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), Art Pearl (manufactured by Negami Chemical Industry Co., Ltd.), and Grand Pearl (manufactured by Aica Kogyo Co., Ltd.).

[0080] Examples of polysaccharides include xanthan gum, guar gum, casein, gum arabic, gelatin, amylose, agarose, agaropectin, arabinan, curdlan, callose, carboxymethyl starch, chitin, chitosan, quince seed, glucomannan, gellan gum, tamarin seed gum, dextran, nigeran, hyaluronic acid, pustulan, funoran, pectin, porphyran, laminaran, lichenan, carrageenan, alginic acid, tragacanth gum, alkaloid gum, and locust bean gum.

[0081] Examples of acrylic or methacrylic resins include polyacrylic acid, polymethacrylic acid, ethylene-methyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene Examples of suitable copolymers include vinyl acetate copolymers. As the acrylic resin or methacrylic resin, for example, commercially available products include the Neocryl series manufactured by Kusumoto Chemicals Co., Ltd.

[0082] Nylons include ε-caprolactam (nylon 6), undecanolactam (nylon 11), lauryllactam (nylon 12), aminocaproic acid, enantholactam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, and α-pyrrolactam. and copolymers obtained by copolymerizing a diamine such as hexamethylenediamine, nonanediamine, nonan-methylenediamine, methylpentadiamine, undecanemethylenediamine, dodecanemethylenediamine, or metaxylenediamine with a carboxylic acid compound such as a dicarboxylic acid such as adipic acid, sebacic acid, terephthalic acid, isophthalic acid, dodecanedicarboxylic acid, or glutaric acid, or a mixture of these polymers or copolymers.

[0083] Examples of commercially available butyral resins include S-LEC (registered trademark) B series, K (KS) series, and SV series manufactured by Sekisui Chemical Co., Ltd., and Mobital (registered trademark) series manufactured by Kuraray Co., Ltd.

[0084] Examples of cyanate ester resins include resins made of at least difunctional aliphatic cyanate esters, at least difunctional aromatic cyanate esters, or mixtures thereof. Specific examples of cyanate ester resins include at least one polymer of at least one polyfunctional cyanate ester selected from the group consisting of 1,3,5-tricyanatobenzene, 1,3-dicyanatonaphthalene, 1,4-dicyanatonaphthalene, 1,6-dicyanatonaphthalene, 1,8-dicyanatonaphthalene, 2,6-dicyanatonaphthalene, and 2,7-dicyanatonaphthalene; bisphenol A cyanate ester resins or hydrogenated products thereof with the addition of hydrogen; bisphenol F cyanate ester resins or hydrogenated products thereof with the addition of hydrogen; 6F bisphenol A dicyanate ester resins, bisphenol E dicyanate ester resins, tetramethyl bisphenol F dicyanate ester resins, bisphenol M dicyanate ester resins, dicyclopentadiene bisphenol dicyanate ester resins, and cyanate novolac resins.

[0085] Examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, phenol novolac epoxy resins, and tert-butyl-catechol. type epoxy resins, naphthalene type epoxy resins, naphthylene ether type epoxy resins, glycidyl amine type epoxy resins, cresol novolac type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexanedimethanol type epoxy resins, trimethylol type epoxy resins, halogenated epoxy resins, etc.

[0086] Thermoplastic elastomers are elastomers that plasticize when heated, and examples thereof include olefin-based elastomers, styrene-based elastomers, vinyl chloride-based thermoplastic elastomers, urethane-based elastomers, polyamide-based elastomers, polyester-based elastomers, polybutadiene-based elastomers, acrylic-based elastomers, and silicone-based elastomers. Examples of the olefin-based elastomer include an olefin-based elastomer in which an olefin-based rubber is finely dispersed in a matrix of an olefin-based resin such as PP. Examples of styrene-based elastomers include styrene-butadiene copolymers, hydrogenated styrene-butadiene copolymers, hydrogenated styrene-isoprene copolymers, styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, hydrogenated styrene-butadiene-styrene block copolymers, and hydrogenated styrene-isoprene-styrene block copolymers. Examples of polyester-based elastomers include polyester-polyether copolymers, polyurethane-polyether / polyester copolymers, and nylon-polyether / polyester copolymers.

[0087] Commercially available products include the TR series (styrene-butadiene thermoplastic elastomer, manufactured by JSR Corporation), the RB series (polybutadiene-based thermoplastic elastomer, manufactured by JSR Corporation), JSR EXELINK (olefin-based thermoplastic elastomer, manufactured by JSR Corporation), the DYNARON (registered trademark) series (hydrogenated thermoplastic elastomer, manufactured by JSR Corporation), Thermorun (registered trademark) (olefin-based thermoplastic elastomer, manufactured by Mitsubishi Chemical Corporation), Epox TPE series (olefin-based thermoplastic elastomer, manufactured by Sumitomo Chemical Co., Ltd.), Septon (registered trademark) series (hydrogenated styrene-based thermoplastic elastomer, manufactured by Kuraray Co., Ltd.), and Tuftec (registered trademark) (hydrogenated styrene-based thermoplastic elastomer, manufactured by Asahi Kasei Corporation). Examples of fluoropolymers other than F polymers include polyvinyl fluoride, polyvinylidene fluoride, and polychlorotrifluoroethylene.

[0088] The different resin may be a binder resin, such as a water dispersion of a vinyl resin, a thermoplastic resin, a curable resin, a thermoplastic block copolymer, or an elastomer. Examples of the vinyl resin include aqueous dispersions of vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include aqueous dispersions of polyolefin resin, ethylene-vinyl acetate copolymer, polyamide resin, and the like. Examples of the curable resin include aqueous dispersions of epoxy resin, urethane resin, polyimide resin, unsaturated polyester resin, etc. The curable resin may be any of room temperature curable resin, thermosetting resin, and photocurable resin.

[0089] The different resin may be a compound that polymerizes or crosslinks with external energy such as heat or light to become the resin, or may be made of a monomer of the resin, a reaction product of the monomer, or a curing agent. Examples of such embodiments include a combination of an isocyanate and a diol in a urethane resin, a combination of a copolymer of bisphenol A and epichlorohydrin in an epoxy resin with a curing agent such as a polyamine or an acid anhydride, and a cyanate ester in a cyanate ester resin. These embodiments are determined appropriately based on the monomers of the different resins selected for inclusion in the dispersion 2. For example, in the case of cyanate esters, the above-mentioned cyanate esters can be used. In the case of epoxy resins, the above-mentioned copolymers that give epoxy resins can be used. Furthermore, the resin components in these embodiments do not need to be completely polymerized or crosslinked, and may be partially unpolymerized or uncrosslinked.

[0090] The present kneaded product 2 in the present method (2) may further contain an inorganic filler. The definition and range of the inorganic filler in the present method (2), including preferred embodiments, are the same as those of the inorganic filler in the present method (1). When the present kneaded product 2 contains an inorganic filler, the amount of the inorganic filler in the present kneaded product 2 is preferably 1 to 50 mass % from the viewpoints of the dispersion stability of the present kneaded product 2 and the present dispersion 2, and the low dielectric loss tangent and low linear expansion of the molded product molded from the present dispersion 2. In the present method (2), the content of liquid compound 1 in the present kneaded product 2 is preferably 10% by mass or more. The content of liquid compound 1 is preferably 60% by mass or less, more preferably 25% by mass or less. This allows the present powder and the present resin to be constantly maintained in a semi-dissolved or swollen state while kneading proceeds, and the present powder, the present resin, and liquid compound 1 are uniformly mixed.

[0091] The solid content of the present kneaded product 2 contains the present powder, the F polymer, and the present different resin. The solid content of the present kneaded product 2 also includes substances other than the present powder and the present different resin that form solid content in a molded product formed from the present dispersion 2, such as the inorganic filler. From the viewpoint of easily obtaining the present paste 2 having excellent dispersibility by kneading, the solid content is preferably 40% by mass or more, and more preferably 50% by mass or more, where the total mass of the present kneaded product 2 is 100% by mass. Moreover, from the viewpoint of dispersibility of the present dispersion, the solid content is preferably 90% by mass or less, and more preferably 75% by mass or less. The solid content may contain non-volatile components other than the powder and the resin, and the total amount of the powder and the resin in the solid content is preferably 60% by mass or more, more preferably 70% by mass or more, based on the total mass of the solid content being 100% by mass. The total amount is preferably 100% by mass or less.

[0092] In the present method (2), the mass ratio of the present powder to the present different resin in the present kneaded product 2 is preferably 0.01 to 0.5 or 2 to 1000, where the mass of the present powder is 1. In this case, the present kneaded product 2 is likely to have excellent dispersibility, and the obtained present dispersion 2 is likely to have excellent dispersion stability. That is, when the above ratio is in the former range, a component that can be considered a composite in which the present powder is coated with the present different resin is formed, and the dispersibility of the present paste 2 is likely to be improved. On the other hand, when the above ratio is in the latter range, the present powder is highly dispersed in the present different resin, and the dispersibility of the present paste 2 is likely to be improved. The ratio in the former range is more preferably 0.005 to 0.2, and even more preferably 0.01 to 0.1. The ratio in the latter range is more preferably 3 to 500, and even more preferably 5 to 100. In this case, the present kneaded product 2 and the present dispersion liquid 2 obtained tend to have excellent dispersion stability even when they do not contain a surfactant.

[0093] Furthermore, apart from the above ratio, from the viewpoints of the dispersion stability of the present kneaded product 2 and the present dispersion 2 and the low dielectric loss tangent of a molded product formed from the present dispersion 2, the amount of the present powder in the solid content of the present kneaded product 2 is preferably 25% by mass or more, and more preferably 50% by mass or more, with the solid content being 100% by mass. The amount of the present powder is preferably 99% by mass or less, and more preferably 90% by mass or less. The amount of the different resin in the solid content is preferably 1% by mass or more, more preferably 5% by mass or more, and is preferably 30% by mass or less, more preferably 20% by mass or less, based on 100% by mass of the solid content. It is more preferable that the amount of the present powder in the solid content is 25% by mass or more, and the amount of the present different resin is 1% by mass or more, assuming that the solid content is 100% by mass.

[0094] In the present method (2), when the present kneaded product 2 is obtained by kneading the composition 2, the composition 2 can be prepared by mixing the present powder, the present different resin, and the liquid compound 1. The mixing method may be a method in which the present powder, the present different resin, and the liquid compound 1 are mixed all at once, or a method in which the present powder, the present different resin, and the liquid compound 1 are mixed while being added sequentially.

[0095] Specific mixing methods include, for example, a method in which the present powder and the present different resin are added to liquid compound 1 all at once and mixed; a method in which the present powder and the present different resin are added to liquid compound 1 sequentially while mixing; a method in which the present powder and the present different resin are mixed in advance and the resulting mixture is mixed with liquid compound 1; a method in which the present powder and liquid compound 1 are mixed in advance, and the present different resin and liquid compound 1 are mixed in advance, and the resulting two mixtures are further mixed. Among the above mixing methods, from the viewpoint of dispersibility of the composition, a method in which the different resin and liquid compound 1 are mixed in advance, and the obtained mixture is then mixed with the powder is preferred.

[0096] In the present method (2), it is preferable to knead the composition 2 to obtain the present kneaded product 2. The present kneaded product 2 in the present method (2) is preferably the present paste 2 or the present dough 2. The present paste 2 preferably contains a surfactant, such as the same surfactants as those used in the present method (1) described above. When the present paste 2 contains a surfactant, the content of the surfactant in the present paste 2 is preferably 1 to 15 mass %. In this case, the affinity between the components increases, and the dispersion stability of the present dispersion 2 is more likely to be improved.

[0097] The present paste 2 containing a surfactant may be prepared by kneading a composition containing the present powder, the present different resin, and a surfactant, or by kneading a composition containing the present powder, the present different resin, and liquid compound 1, and then adding a surfactant and kneading the mixture, or by kneading a composition containing the present powder, a surfactant, and liquid compound 1, and then adding the present different resin and kneading the mixture, or it is preferably prepared by kneading a composition containing the present powder, the present different resin, and liquid compound 1, and then adding a surfactant and kneading the mixture. In this case, the present powder is more likely to be subjected to shear when the composition is kneaded, the viscosity of the present paste 2 is reduced, and the dispersion stability of the present dispersion 2 obtained is more likely to be improved. In addition, a preferred method for obtaining the present dispersion 2 containing the present different resin, a surfactant, and an inorganic filler is to knead a mixture of the inorganic filler and the present powder with the liquid compound 1 and the present different resin to obtain a kneaded mixture, knead the kneaded mixture with the surfactant to obtain the present paste 2, and then mix the present paste 2 with the liquid compound 2.

[0098] When the present dispersion contains both an inorganic filler and the different resin as other materials, the present method may be carried out in such a manner that a mixture containing the present powder and the inorganic filler is kneaded with a mixture containing the different resin and liquid compound 1 to obtain the present kneaded mixture, and then the kneaded mixture is mixed with liquid compound 2 to obtain the present dispersion. The mixture containing the present powder and the inorganic filler is preferably in powder form. This embodiment not only improves the dispersion stability of the kneaded mixture and the resulting dispersion, but also tends to improve the storage stability of the dispersion during long-term storage. Furthermore, when the present dispersion is left standing at 25°C for 30 days, the absolute value of the fluctuation range of the thixotropy ratio is preferably 3 or less, and preferably less than 1. In such an embodiment, the present kneaded product or the present dispersion preferably does not contain a surfactant. Even if a surfactant is not contained, the present paste and the resulting present dispersion tend to have excellent dispersion stability, and a molded product with excellent electrical properties is likely to be obtained. These effects tend to be particularly significant when the present kneaded product is the present powder.

[0099] This dispersion is applied to the surface of a substrate and heated to form a layer made of the F polymer (hereinafter also referred to as the F layer), thereby producing a laminate having the substrate and the F layer. In producing the laminate, it is sufficient that an F layer is formed on at least one surface of the substrate, and an F layer may be formed on only one surface of the substrate, or an F layer may be formed on both surfaces of the substrate. The surface of the substrate may be surface-treated with a silane coupling agent or the like. The dispersion can be applied by any of the following coating methods: spraying, roll coating, spin coating, gravure coating, microgravure coating, gravure offset, knife coating, kiss coating, bar coating, die coating, fountain-meyer bar coating, and slot die coating.

[0100] The F layer is preferably formed by removing the liquid compound 1 and liquid compound 2 (hereinafter also collectively referred to as liquid compounds) by heating, and then baking the F polymer by further heating. The temperature for removing the liquid compounds is preferably as low as possible, and is preferably 50 to 150°C lower than the lower of the boiling points of liquid compounds 1 and 2. For example, when N-methyl-2-pyrrolidone, which has a boiling point of about 200°C, is used as liquid compounds 1 and 2, it is preferable to heat the dispersion to 150°C or lower, preferably 100 to 120°C. It is preferable to blow air in the step of removing the liquid compounds. After removing the liquid compound, the substrate is preferably heated to a temperature range where the F polymer is baked to form an F layer, and for example, the F polymer is preferably baked in the range of 300 to 400° C. That is, the F layer preferably contains a baked product of the F polymer.

[0101] As described above, the F layer is formed through the steps of coating the dispersion, drying, and baking. Each of these steps may be carried out once or twice or more times. For example, the F layer may be formed by applying the present dispersion to the surface of a substrate, heating to remove the liquid compound, and then repeating the process of forming a film twice, and then heating the thicker film to bake the F polymer. From the viewpoint of easily obtaining a thick F layer with excellent smoothness, it is preferable to carry out the steps of applying and drying the present dispersion twice. 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.

[0102] The peel strength between the F layer and the substrate 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 the present dispersion, the present 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, and is preferably 0.01% or more, more preferably 0.1% or more. The void ratio is determined by determining the void area in the F layer through image processing of an SEM photograph of the cross section of the molded product observed using a scanning electron microscope (SEM), and is the percentage (%) obtained by dividing the area occupied by the void area by the area of ​​the F layer. The area occupied by the void area is calculated by approximating the void area as a circle.

[0103] Examples of the substrate include metal substrates such as metal foils of copper, nickel, aluminum, titanium, alloys thereof, etc.; resin films such as polyimide, polyarylate, polysulfone, polyarylsulfone, polyamide, polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamideimide, liquid crystalline polyester, and liquid crystalline polyesteramide; and prepregs which are precursors of fiber-reinforced resin substrates. The shape of the substrate may be flat, curved or irregular, and may further be any of foil, plate, film or fiber. The ten-point mean roughness of the substrate surface is preferably less than 0.1 μm, more preferably 0.05 μm or less. The ten-point mean roughness is preferably 0.001 μm or more. Even with such an unroughened substrate, a laminate with excellent peel strength can be obtained from the dispersion, and a printed circuit board or the like with excellent transmission characteristics can be formed from such a laminate. The ten-point mean roughness of the substrate surface is the value specified in Appendix JA of JIS B 0601:2013. The thickness of the substrate is preferably 2 to 100 μm. When the substrate is a metal foil, the thickness of the substrate is preferably 1 to 35 μm. The substrate may also be a metal foil with a carrier, which is an ultrathin copper foil having a thickness of 2 to 5 μm laminated on a carrier copper foil via a release layer.

[0104] Suitable embodiments of the laminate include a metal-clad laminate having a metal foil and an F layer formed on at least one surface thereof, and a multilayer film having a resin film and an F layer formed on at least one surface thereof. The metal foil in the metal clad laminate is preferably copper foil, and such a metal clad laminate is particularly useful as a printed circuit board material. 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. Specific examples of polyimide films include "Kapton 50EN-S" (manufactured by DuPont-Toray Co., Ltd.), "Kapton 100EN" (manufactured by DuPont-Toray Co., Ltd.), "Kapton 100H" (manufactured by DuPont-Toray Co., Ltd.), "Kapton 100KJ" (manufactured by DuPont), "Kapton 100JP" (manufactured by DuPont-Toray USA), and "Kapton 100LK" (manufactured by DuPont-Toray Co., Ltd.). The printed circuit board includes a flexible printed circuit board and a rigid printed circuit board.

[0105] A multilayer laminate may be formed by laminating another substrate on the opposite side of the substrate of Layer F. Lamination can be performed, for example, by thermocompression bonding. Examples of the structure of such a multilayer laminate include substrate / F layer / other substrate / F layer / substrate, metal substrate layer / other substrate layer / F layer / other substrate layer / metal substrate layer, etc. Each layer may further contain glass cloth or filler. Such laminates are useful as antenna parts, printed circuit boards, aircraft parts, automobile parts, sports equipment, food industry supplies, paints, cosmetics, etc., and specifically as wire coating materials for aircraft electric wires, etc., 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, etc., copy rolls, covers for furniture, automobile dashboards, home appliances, etc., sliding members such as load bearings, sliding shafts, valves, bearings, gears, cams, belt conveyors, and food transport belts, tools such as shovels, files, saws, and other tools, boilers, hoppers, pipes, ovens, baking molds, chutes, dies, toilets, and container coating materials.

[0106] The dispersion is impregnated into a woven fabric, which is then dried by heating to obtain an impregnated woven fabric in which the F polymer is impregnated into the woven fabric. The impregnated woven fabric can also be called a coated woven fabric in which the woven fabric is coated with an F layer or embedded in 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 enhance adhesion to the F layer. The total content of the F polymer in the impregnated woven fabric is preferably 30 to 80% by mass. Methods for impregnating the woven fabric with the dispersion include immersing the woven fabric in the dispersion and applying the dispersion to the woven fabric.

[0107] When drying the woven fabric, the F polymer may be calcined, for example, 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 polymer may be carried out in one step. The impregnated woven fabric has excellent properties such as high adhesion (adhesion) between the F layer and the woven fabric, high surface smoothness, and little distortion. By thermocompression bonding such an impregnated woven fabric and a metal foil, a metal clad laminate having high peel strength and resistance to warping can be obtained, which can be suitably used as a material for printed circuit boards.

[0108] In addition, in the production of an impregnated woven fabric, a woven fabric impregnated with the present dispersion may be placed on the surface of a substrate by adhering or the like, and then heated and dried to form an impregnated woven fabric layer containing the F polymer and the woven fabric, thereby producing a laminate in which the substrate and the impregnated woven fabric layer are laminated in this order. The mode of production is not particularly limited, and by attaching a woven fabric impregnated with the present dispersion to part or all of the inner wall surface of a member such as a tank, pipe, or container, and then heating the member while rotating, an impregnated woven fabric layer can be formed on part or all of the inner wall surface of the member. This production method is also useful as a method for lining the inner wall surface of members such as tanks, pipes, and containers.

[0109] As described above, the present dispersion has excellent dispersion stability and can be efficiently impregnated into porous or fibrous materials, including 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 an inorganic filler, etc. These materials may also 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 embodiment in which a molded article is produced by impregnating such a material with the present dispersion includes an embodiment in which a fibrous material carrying a curable resin or a cured product thereof is impregnated with the present dispersion.

[0110] Examples of fibrous materials include high-strength, low-elongation fibers such as carbon fibers, aramid fibers, silicon carbide fibers, etc. Preferred curable resins are thermosetting resins such as epoxy resins, unsaturated polyester resins, and polyurethane resins. 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 present dispersion 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, fisheries, and slings.

[0111] As described above, according to the present method, the present kneaded product is obtained by kneading the present powder, at least one other material selected from the group consisting of an inorganic filler and the present different resin, with liquid compound 1, and the present kneaded product is mixed with liquid compound 2 to obtain the present dispersion liquid having excellent dispersibility and dispersion stability.

[0112] Although the method for producing the dispersion, the paste, and the kneaded powder of the present invention have been described above, the present invention is not limited to the configurations of the above-described embodiments. For example, the method for producing a dispersion of the present invention may have any other step added to the configuration of the above embodiment, or may be replaced with any other step that produces a similar effect. Furthermore, in the paste and dough of the present invention, any other components may be added to the components of the above-described embodiments, or any other components that exhibit the same function may be substituted. [Example]

[0113] 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 ingredient [powder] Powder 1: 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 with a main chain carbon number of 1 × 10 6 Powder made of polymer with 1000 particles per particle (D50: 2.1 μm) Powder 2: Contains 98.7 mol% TFE units and 1.3 mol% PPVE units, in that order, and has a carbonyl group with a main chain carbon number of 1 × 10 6Powder made of polymer with 40 particles per particle (D50: 1.8 μm)

[0114] [Inorganic filler] Filler 1: Hollow spherical silica filler (D50: 0.7 μm, surface treated with a silane coupling agent) Filler 2: Solid silica filler (D50: 0.4 μm, particle strength: 20 MPa or more) Filler 3: Steatite filler Filler 4: A flake-like filler made of boron nitride (D50: 14.6 μm)

[0115] [Aromatic polymer] Varnish 1: Varnish in which thermoplastic aromatic polyimide (PI1) is dissolved in NMP [Surfactants] Surfactant 1: CH2=C(CH3)C(O)OCH2CH2(CF2)6F and CH2=C(CH3)C(O)(OCH2CH2) 23 Copolymer with OH [Liquid compounds] NMP: N-methyl-2-pyrrolidone [Polyimide film] Polyimide film 1: Aromatic polyimide film with a thickness of 50 μm (manufactured by Toray DuPont Co., Ltd., "Kapton 100LK")

[0116] 2. Dispersion liquid production example [Example 1] First, Powder 1 and NMP were placed in a pot and mixed, followed by Filler 1, Filler 2, Surfactant 1 and Varnish 1, which were then mixed to prepare a liquid composition. The prepared liquid composition was then added to a planetary mixer and kneaded to obtain Paste 1 containing Powder 1 (35 parts by mass), Filler 1 (14 parts by mass), Filler 2 (14 parts by mass), PI1 (7 parts by mass), Surfactant 1 (3 parts by mass), and NMP (27 parts by mass). The viscosity of Paste 1 was 28,000 mPa s. NMP was added to Paste 1 in several batches, stirred, and degassed for 1 minute at 2000 rpm using a planetary centrifugal mixer. Furthermore, NMP was added in several batches and stirred, and a total of 80 parts by mass of NMP was added to Paste 1, yielding Dispersion 1. The viscosity of Dispersion 1 was 400 mPa s.

[0117] [Examples 2 to 4] Pastes 2 to 4 were obtained in the same manner as Paste 1, except that the types or amounts of the powder and filler were changed, and Dispersions 2 to 4 were prepared in the same manner as Dispersion 1.

[0118] [Example 5] Varnish 1 and NMP were placed in a pot and mixed. Furthermore, a dry blend of Powder 1, Filler 1 and Filler 2 was placed in the pot and mixed to prepare a liquid composition. The liquid composition was then added to a planetary mixer and kneaded. Surfactant 1 was then added to the planetary mixer and kneaded to obtain Paste 5, which contained Powder 1 (35 parts by mass), Filler 1 (14 parts by mass), Filler 2 (14 parts by mass), PI1 (7 parts by mass), Surfactant 1 (3 parts by mass), and NMP (27 parts by mass). The viscosity of Paste 5 was 11,000 mPa s. NMP was added to Paste 5 in several batches and stirred, and the mixture was degassed for 1 minute at 2000 rpm using a planetary centrifugal mixer. Furthermore, NMP was added in several batches and stirred, and a total of 80 parts by mass of NMP was added to Paste 5 to prepare a dispersion, yielding Dispersion 5. The viscosity of Dispersion 5 was 200 mPa s.

[0119] [Example 6] Varnish 1 and NMP were placed in a pot and mixed, and then Powder 1 was placed in the pot and mixed to prepare a liquid composition. The prepared liquid composition was then charged into a planetary mixer and kneaded to obtain Paste 6 containing Powder 1 (5 parts by mass), PI1 (50 parts by mass), and NMP (45 parts by mass). The viscosity of Paste 6 was 30,000 mPa·s. NMP was added to Paste 6 in several batches, stirred, and degassed for 1 minute at 2000 rpm using a planetary centrifugal mixer. Furthermore, NMP was added in several batches, and a total of 80 parts by mass of NMP was added to Paste 6 to prepare a dispersion, yielding Dispersion 6. The viscosity of Dispersion 6 was 300 mPa s.

[0120] [Example 7 (Comparative Example)] Powder 1, Filler 1, Filler 2, Varnish 1, Surfactant 1, and NMP were placed in a pot, and zirconia balls were then placed in. The pot was then rolled at 150 rpm for 1 hour to obtain Dispersion 7 containing Powder 1 (35 parts by mass), Filler 1 (14 parts by mass), Filler 2 (14 parts by mass), PI1 (7 parts by mass), Surfactant 1 (3 parts by mass), and NMP (97 parts by mass) without obtaining a paste.

[0121] The ingredients and viscosities of each paste are summarized in Table 1 below. [Table 1]

[0122] [Example 8] Varnish 1 and NMP were added to a pot and mixed. A powder mixture of Powder 1 and Filler 4 was then added to the pot and mixed to prepare a composition. This composition was kneaded in a planetary mixer and then removed to obtain Dough 1, which contained Powder 1 (50 parts by mass), Filler 4 (40 parts by mass), PI1 (10 parts by mass), and NMP (30 parts by mass). Dough 1 was lumpy and clay-like. NMP was added to the kneaded powder 1 in several batches while stirring at 2000 rpm with a planetary centrifugal mixer while degassing. Furthermore, NMP was added in several batches, and a total of 80 parts by mass of NMP was added to the kneaded powder 1 to prepare a dispersion, and dispersion 8 was obtained. The viscosity of dispersion 8 was 300 mPa s.

[0123] [Example 9] Powder 1, Filler 4, Varnish 1, and NMP were added to a pot and mixed to prepare a composition. This composition was kneaded in a planetary mixer and then removed to obtain Dough 2, which contained Powder 1 (50 parts by weight), Filler 4 (40 parts by weight), PI1 (10 parts by weight), and NMP (30 parts by weight). Dough 2 was lumpy and clay-like. NMP was added to the kneaded powder 2 in several batches while stirring at 2000 rpm with a planetary centrifugal mixer while degassing. Furthermore, NMP was added in several batches, and a total of 80 parts by mass of NMP was added to the kneaded powder 2 to prepare a dispersion, and dispersion 9 was obtained. The viscosity of dispersion 9 was 300 mPa s.

[0124] [Example 10 (Comparative Example)] Powder 1 (35 parts by mass) and Filler 1 (30 parts by mass) were added and stirred and mixed to obtain Powder Mixture 1. The obtained Powder Mixture 1 was mixed with NMP (110 parts by mass) to obtain Dispersion Liquid 10. Immediately after preparation, precipitation of aggregates was visually observed in Dispersion Liquid 10, and the dispersibility was poor.

[0125] A paste equivalent to Paste 1 was also obtained by kneading in the same manner as in Example 1, except that a dry blend of Powder 1, Filler 1, and Filler 2 was added to a planetary mixer and then a liquid composition containing Surfactant 1, Varnish 1, and NMP was added.

[0126] 3. Example of laminate manufacturing [Laminate 1] Dispersion Liquid 1 after long-term storage was applied to the surface of a long copper foil with a thickness of 18 μm using a bar coater to form a wet film. The copper foil with this wet film 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 a nitrogen oven. This produced Laminate 1, which had a copper foil and a 20 μm-thick polymer layer on its surface as a molded product containing the molten and fired product of Powder 1, Filler 1, Filler 2, and PI1.

[0127] [Laminates 2 to 9] Laminates 2 to 9 were produced in the same manner as Laminate 1, except that Dispersion 1 was changed to Dispersions 2 to 9. In Laminates 8 and 9, the thickness of the polymer layer was set to 50 μm. Dispersion 10 had poor dispersibility, so no laminates were produced from it.

[0128] [Laminate 10] Dispersion 1 was applied to the surface of a long copper foil with a thickness of 18 μm using a bar coater to form a wet film. Next, the copper foil on which this wet film was formed was passed through a drying oven at 110 ° C for 5 minutes and dried by heating to obtain a dry film. Furthermore, the dispersion was applied to the dry film using a bar coater to form a wet film, and then the dry film and the copper foil on which the wet film was formed were passed through a drying oven at 110 ° C for 5 minutes and dried by heating to obtain a two-layer dry film. Thereafter, a polymer layer with a thickness of 50 μm was formed in the same manner as in the laminate 1, and laminate 10 was produced. Furthermore, when the cross section of the polymer layer was observed using a scanning electron microscope (SEM), the porosity of the polymer layer of the laminates other than laminate 7 was 5% or less, and the porosity of the polymer layer of laminate 7 was more than 5%.

[0129] 4. Evaluation 4-1. Evaluation of dispersion stability of dispersion liquid After each dispersion was stored in a container at 25°C for a long period of time, its dispersibility was visually confirmed and the dispersion stability was evaluated according to the following criteria. [Evaluation criteria] ◯: No aggregates are visible. △: Fine aggregates were visible on the side wall of the container. Upon gentle stirring, the mixture was uniformly redispersed. ×: Aggregates were visible at the bottom of the container. Strong shear stirring was required for redispersion.

[0130] 4-2. Evaluation of thixotropy stability of dispersion Each dispersion was stored in a container at 25°C for 30 days, and the range of change in the thixotropy ratio before and after storage was measured, and the thixotropy stability was evaluated according to the following criteria. [Evaluation criteria] ○: The fluctuation range (absolute value) of the thixotropy ratio is less than 1 △: The fluctuation range (absolute value) of the thixotropy ratio is 1 or more and 3 or less ×: The fluctuation range (absolute value) of the thixotropy ratio is more than 3

[0131] The evaluation results for the dispersion are shown in Table 2 below. [Table 2]

[0132] 4-3. Evaluation of the linear expansion coefficient of laminates For each laminate, the copper foil of the laminate was removed by etching with an aqueous ferric chloride solution to produce a single polymer layer. Square test pieces measuring 180 mm square were cut from the produced polymer layer, and the linear expansion coefficients of the test pieces were measured in the range of 25°C to 260°C in accordance with the measurement method specified in JIS C 6471:1995, and evaluated according to the following criteria. Note that Laminate 7 was not evaluated because the porosity of the polymer layer was high. [Evaluation criteria] ○: Less than 50 ppm / ℃. △: More than 50 ppm / ℃ and 75 ppm / ℃ or less. ×: More than 75 ppm / °C.

[0133] 4-4. Evaluation of dielectric loss tangent of laminate For each laminate, the copper foil of the laminate was removed by etching with an aqueous ferric chloride solution to produce a single polymer layer, and the dielectric loss tangent of the polymer layer (measurement frequency: 10 GHz) was measured using the SPDR (split post dielectric resonance) method and evaluated according to the following criteria. Note that Laminate 7 was not evaluated because the porosity of the polymer layer was high. [Evaluation criteria] ◯: The dielectric loss tangent is less than 0.0010. △: The dielectric loss tangent is 0.0010 or more and 0.0025 or less. ×: The dielectric loss tangent is more than 0.0025.

[0134] The evaluation results for the laminate are shown in Table 3 below. [Table 3]

[0135] 5. Example of laminated film manufacturing Dispersion 3 prepared from paste 3 was applied to one side of polyimide film 1 by a small-diameter gravure reverse method, and the film was passed through a ventilation drying oven at a furnace temperature of 150°C for 3 minutes to remove the NMP and form a dry coating. Furthermore, the dispersion liquid 3 was similarly applied to the other surface of the polyimide film 1 and dried to form a dry coating. Next, the polyimide film with the dry coatings formed on both sides was passed through a far-infrared oven for 20 minutes to melt and bake Powder 1. The oven temperature near the inlet and outlet of the far-infrared oven was 300°C, and the oven temperature near the center was 340°C. As a result, a 25 μm-thick polymer layer containing F polymer 1 and PI1 was formed on both sides of Polyimide Film 1, and Laminated Film 1 was obtained in which the polymer layer, the polyimide film, and the polymer layer were directly formed in this order. When the cross section of the laminated film 1 was observed using a scanning electron microscope (SEM), the porosity of the polymer layer was found to be 5% or less. The linear expansion coefficient and dielectric loss tangent of the laminated film 1 were evaluated in the same manner as above, and the linear expansion coefficient was "good" and the dielectric loss tangent was "good". [Industrial Applicability]

[0136] As is clear from the above results, the dispersion prepared by this method was excellent in dispersibility and dispersion stability, and the cross section of the laminate obtained by applying it to a substrate was dense and void-free. Therefore, the laminate using the dispersion prepared by this method had excellent uniformity of component distribution and excellent physical properties.

Claims

1. A method for producing a dispersion, comprising kneading a tetrafluoroethylene-based polymer powder, at least one other material selected from the group consisting of an inorganic filler and a resin different from the tetrafluoroethylene-based polymer, and a liquid compound to obtain a kneaded mixture having a solid content of 50 mass% or more, and mixing the kneaded mixture with the liquid compound to obtain a dispersion in which the tetrafluoroethylene-based polymer powder is dispersed and which has a viscosity of 50 mPa s or more and less than 10,000 mPa s.

2. The manufacturing method according to claim 1 , wherein the kneaded product contains the inorganic filler, and a ratio of the powder to the inorganic filler in the kneaded product is 0.5 to 2 by mass relative to the powder mass being 1.

3. The method according to claim 1 or 2, wherein the inorganic filler is a silica filler or a boron nitride filler.

4. 4. The manufacturing method according to claim 1, wherein the kneaded product contains the different resin, and a ratio of the powder to the different resin in the kneaded product is such that the mass of the powder is 1 and the mass of the different resin is 0.01 to 0.

5.

5. The manufacturing method according to any one of claims 1 to 3, wherein the kneaded product contains the different resin, and a ratio of the powder to the different resin in the kneaded product is such that the mass of the powder is 1 and the mass of the different resin is 2 to 1000.

6. The method of claim 1 , wherein the different resin is an aromatic polymer.

7. The method according to claim 1 , wherein the liquid compound is a low-viscosity liquid or a high-viscosity liquid.

8. A method for producing a dispersion comprising kneading a tetrafluoroethylene-based polymer powder, a resin other than the tetrafluoroethylene-based polymer, a liquid compound, and a surfactant to obtain a kneaded mixture having a solid content of 50 mass% or more, and mixing the kneaded mixture with the liquid compound to obtain a dispersion in which the tetrafluoroethylene-based polymer powder is dispersed and which has a viscosity of 50 mPa s or more and less than 10,000 mPa s.

9. A method for producing a dispersion comprising kneading a mixture containing a tetrafluoroethylene-based polymer powder and an inorganic filler with a mixture containing a resin different from the tetrafluoroethylene-based polymer and a liquid compound to obtain a kneaded mixture having a solid content of 50 mass% or more, and mixing the kneaded mixture with the liquid compound to obtain a dispersion in which the tetrafluoroethylene-based polymer powder is dispersed and which has a viscosity of 50 mPa·s or more and less than 10,000 mPa·s.

10. A paste having a solid content of 40 mass% or more and a viscosity of 800 to 100,000 mPa s, obtained by kneading a powder of a tetrafluoroethylene-based polymer, at least one other material selected from the group consisting of an inorganic filler and a resin different from the tetrafluoroethylene-based polymer, and a liquid compound.

11. The paste according to claim 10, comprising the inorganic filler, wherein the ratio of the powder to the inorganic filler is 1 by mass of the powder to 0.5 to 2 by mass of the inorganic filler.

12. 12. The paste according to claim 10 or 11, comprising the different resin, wherein the ratio of the powder to the different resin is 1 by mass of the powder to 0.01 to 0.5 by mass of the different resin.

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