Composition, method for producing the composition, and method for producing a sheet

Abstract

This composition includes: particles containing polytetrafluoroethylene; particles containing a heat-fusible tetrafluoroethylene polymer; a liquid compound with a surface tension of less than 72 dyn / cm or water; and a surfactant. The content by mass of the liquid compound or water is less than the total content by mass of the particles containing polytetrafluoroethylene and the particles containing a heat-fusible tetrafluoroethylene polymer. The surface tension of a mixture of water and the surfactant is less than 72 dyn / cm.

Description

Technical Field

[0001] The present disclosure relates to a composition, a method for producing the composition, and a method for producing a sheet.

Background Art

[0002] Polytetrafluoroethylene is excellent in physical properties such as electrical insulation, water and oil repellency, chemical resistance, and heat resistance. Therefore, a dispersion in which polytetrafluoroethylene particles are dispersed in water or an oily solvent is useful as a material for forming resists, adhesives, electrical insulating layers, lubricants, inks, paints, and the like. When polytetrafluoroethylene is used as the above material, functional particles such as other fluororesins and inorganic particles other than polytetrafluoroethylene may be used in combination with polytetrafluoroethylene. However, polytetrafluoroethylene has a low surface energy, and its particles tend to aggregate. In addition, since the affinity between polytetrafluoroethylene particles and functional particles is low, it may be difficult to mix them without causing aggregation of both. As an example of a method for mixing a fluororesin and inorganic particles, for example, a method of separately preparing a co-aggregated powder obtained from a dispersion containing polytetrafluoroethylene particles and inorganic particles and then preparing a paste (see Japanese Patent Application Laid-Open No. 2015-44288) is known. Further, a method of mixing a mixture of polytetrafluoroethylene particles, copolymer particles of tetrafluoroethylene and perfluoropropyl vinyl ether, and inorganic particles with a large amount of naphtha as a molding aid to prepare a paste (see paragraph number "0050" of Japanese Patent Application Laid-Open No. 2015-164801) is known.

Summary of the Invention

Problems to be Solved by the Invention

[0003] However, the method described in Japanese Patent Publication No. 2015-44288 requires the separate preparation of co-aggregated powder, resulting in low production efficiency. Furthermore, the method described in Japanese Patent Publication No. 2015-164801 uses a large amount of naphtha as a molding aid to disperse polytetrafluoroethylene particles, requiring the removal of the molding aid, resulting in low production efficiency. This disclosure is made in view of the above-mentioned conventional circumstances, and aims to provide a composition that can shorten the process and time required for molding a molded product and can form a molded product in which powder shedding and the generation of aggregates are suppressed, a method for manufacturing this composition, and a method for manufacturing a sheet using this composition. [Means for solving the problem]

[0004] The specific means for achieving the aforementioned objectives are as follows: <1> A composition comprising particles containing polytetrafluoroethylene, particles containing a heat-meltable tetrafluoroethylene polymer, and a liquid compound having a surface tension of less than 72 dyn / cm, wherein the mass content of the liquid compound is less than the mass content of the polytetrafluoroethylene particles and the heat-meltable tetrafluoroethylene polymer particles. <2> The liquid compound comprises at least one selected from the group consisting of hydrocarbons and alcohols. <1> The composition described above. <3> The liquid compound comprises at least one selected from the group consisting of ethylene glycol, glycerin, and propylene glycol. <1> or <2> The composition described above. <4> A composition comprising particles containing polytetrafluoroethylene, particles containing a heat-meltable tetrafluoroethylene polymer, water, and a surfactant, wherein the mass content of the water is less than the mass content of the polytetrafluoroethylene particles and the heat-meltable tetrafluoroethylene polymer, and the surface tension of the mixture of water and the surfactant is less than 72 dyn / cm. <5> The melting temperature of the aforementioned heat-meltable tetrafluoroethylene polymer is 200 to 320°C. <1> ~ <4> A composition according to any one of the items. <6> The aforementioned heat-meltable tetrafluoroethylene polymer has an oxygen-containing polar group. <1> ~ <5> A composition according to any one of the items. <7> The proportion of particles containing polytetrafluoroethylene to the total of the particles containing polytetrafluoroethylene and the particles containing the heat-meltable tetrafluoroethylene polymer is 40 to 80% by mass. <1> ~ <6> A composition according to any one of the items. <8> Further containing inorganic particles <1> ~ <7> A composition according to any one of the items. <9> The inorganic particles include at least one selected from the group consisting of silica, boron nitride, and titanium dioxide. <8> The composition described above. <10> The amount of inorganic particles is 15% by mass or more relative to the total amount of the composition. <8> or <9> The composition described above. <11> Further comprising an aromatic polymer or its precursor <1> ~ <10> A composition according to any one of the items. <12> It is a mixture. <1> ~ <11> A composition according to any one of the items. <13> A method for producing a composition, comprising kneading particles containing polytetrafluoroethylene, particles containing a heat-meltable tetrafluoroethylene polymer, and a liquid compound having a surface tension of less than 72 dyn / cm to obtain a composition in which the mass-based content of the liquid compound is less than the mass-based total content of the particles containing polytetrafluoroethylene and the particles containing the heat-meltable tetrafluoroethylene polymer. <14> A method for producing a composition, comprising kneading particles containing polytetrafluoroethylene, particles containing a heat-meltable tetrafluoroethylene polymer, water, and a surfactant to obtain a composition in which the mass-based content of water is less than the mass-based total content of the particles containing polytetrafluoroethylene and the particles containing the heat-meltable tetrafluoroethylene polymer, and the surface tension of the mixture of water and the surfactant is less than 72 dyn / cm. <15> <1> ~ <12> A method for producing a sheet, comprising molding a composition described in any one of the items to obtain a sheet. [Effects of the Invention]

[0005] This disclosure provides a composition that can shorten the process and time required for molding a molded product and can form a molded product in which powder shedding and the generation of aggregates are suppressed, a method for manufacturing this composition, and a method for manufacturing a sheet using this composition. [Modes for carrying out the invention]

[0006] The embodiments of this disclosure are described in detail below. However, this disclosure is not limited to the embodiments described below. In the embodiments described below, the components (including elemental steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit this disclosure.

[0007] In this disclosure, the numerical range indicated using "~" includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values ​​shown in the composite examples. In this disclosure, each component may contain multiple types of the corresponding substance. If multiple types of the substance corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple types of substances present in the composition, unless otherwise specified. In this disclosure, each component may include multiple types of particles. If multiple types of particles corresponding to each component are present in the composition, the particle size of each component refers to the value for a mixture of such multiple types of particles present in the composition, unless otherwise specified. In this disclosure, the term "layer" includes cases where, when observing the region in which the layer exists, it is formed not only over the entire region but also over only a portion of the region. In this disclosure, the term "lamination" refers to stacking layers, and two or more layers may be bonded together or detachable. In this disclosure, "polymer" is a compound formed by the polymerization of monomers. That is, "polymer" has multiple units based on monomers. In this disclosure, "unit" in a polymer means an atomic group based on a monomer formed by the polymerization of a monomer. A unit may be a unit directly formed by a polymerization reaction, or a unit in which a portion of the unit is converted to a different structure by processing the polymer. Hereinafter, a unit based on monomer a will also be simply referred to as "monomer a unit." In this disclosure, “melting temperature” is the temperature corresponding to the maximum value of the melting peak of the polymer measured by differential scanning calorimetry (DSC). In this disclosure, "melt flow rate" means the melt mass flow rate of the polymer as defined in JIS K 7210-1:2014 (ISO 1133-1:2011). In this disclosure, "glass transition temperature (Tg)" is a value measured by analyzing the polymer using the dynamic viscoelasticity measurement (DMA) method. In this disclosure, the "volume-average particle diameter (D50)" of a particle is the volume-based cumulative 50% diameter of the particle, determined by the laser diffraction-scattering method. That is, the particle size distribution is measured by the laser diffraction-scattering method, the cumulative curve is determined with the total volume of the particle collection set to 100%, and the D50 is the particle diameter at the point on that cumulative curve where the cumulative volume is 50%. The D50 of a particle is determined by dispersing the particle in water and analyzing it using the laser diffraction / scattering method with a laser diffraction / scattering particle size distribution analyzer (for example, the LA-920 analyzer manufactured by Horiba, Ltd.). In this disclosure, the "aspect ratio" of a particle refers to the ratio of its major axis to its minor axis (major axis / minor axis) when the particle is observed using a scanning electron microscope (SEM). The aspect ratio of a particle is the average of the aspect ratios of 100 randomly selected particles. In this disclosure, "specific surface area" is a value calculated by measuring particles using the gas adsorption (constant volume) BET multipoint method, and is determined using NOVA4200e (manufactured by Quantachrome Instruments). In this disclosure, "surface tension" refers to the value measured under conditions of 25°C using the plate method (Wilhelmy method). Surface tension can be measured using an automatic surface tension meter, model CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.).

[0008] The first composition of this disclosure comprises particles containing polytetrafluoroethylene (hereinafter also referred to as PTFE) (hereinafter also referred to as PTFE particles), particles containing a heat-meltable tetrafluoroethylene polymer (hereinafter also referred to as F polymer) (hereinafter also referred to as F particles), and a liquid compound having a surface tension of less than 72 dyn / cm (hereinafter also referred to as a specific liquid compound), wherein the mass-based content of the specific liquid compound is less than the mass-based total content of the PTFE particles and the F particles. The second composition of this disclosure comprises PTFE particles, F particles, water, and a surfactant, wherein the mass-based content of the water is less than the mass-based total content of the PTFE particles and the F particles, and the surface tension of the mixture of the water and the surfactant is less than 72 dyn / cm. Note that the unit of surface tension, "dyn / cm," is the same as "mN / m," and 1 dyn / cm is equal to 1 mN / m. Hereinafter, the first composition and the second composition will be collectively referred to as the present composition.

[0009] This composition can shorten the process and time required for molding the product, and can form a molded product with suppressed powder shedding and aggregate formation. The reason for this is not clear, but it is presumed to be as follows. In addition to PTFE particles, this composition uses F particles containing an F polymer that has high compatibility with PTFE and is relatively likely to interact with components other than PTFE. Therefore, in this composition, the presence of F particles promotes the interaction between PTFE particles and components other than PTFE particles. Also, since both PTFE and the F polymer are resins with low surface tension, when this composition contains a specific liquid compound with low surface tension or water and a surfactant, the wetting of F particles is promoted, and thereby the wetting of PTFE particles is also promoted. As a result, even if the content of the specific liquid compound or water in this composition is less than the total content of PTFE particles and F particles, it is presumed that the PTFE particles and F particles are well mixed and uniformly distributed, and the generation of aggregates is suppressed. By being able to reduce the specific liquid compound or water contained in this composition, when obtaining a molded product using this composition, the removal time of the specific liquid compound or water can be shortened. As a result, according to this composition, the time required for molding the molded product can be shortened. Also, it is presumed that the generation of aggregates is suppressed, so that powder falling from the molded product obtained by molding this composition is suppressed. Furthermore, it is presumed that the physical properties such as electrical properties and adhesiveness of the molded product obtained by molding this composition are improved by suppressing the generation of aggregates.

[0010] Hereinafter, each component constituting this composition will be described.

[0011] PTFE may be a homopolymer of tetrafluoroethylene (hereinafter also referred to as TFE), or a so-called modified PTFE which is a copolymer of TFE and a comonomer such as a trace amount of perfluoro(alkyl vinyl ether) (hereinafter also referred to as PAVE), hexafluoropropylene (hereinafter also referred to as HFP), fluoroalkyl ethylene, etc. The proportion of TFE units in PTFE is 99.5 mol% or more, preferably 99.9 mol% or more, of all units. PTFE is preferably non-thermally fusible.

[0012] PTFE is preferred if its number-average molecular weight Mn, calculated based on the following formula (1), is 200,000 or more. Mn = 2.1 × 10⁻⁶ 10 ×ΔHc -5.16 ... (1) In equation (1), Mn represents the number-average molecular weight of PTFE, and ΔHc represents the calorific value (cal / g) of PTFE as measured by differential scanning calorimetry.

[0013] The D50 of the PTFE particles is preferably 0.1 μm or larger, more preferably 0.2 μm or larger. The D50 of the PTFE particles is preferably 3 μm or smaller, more preferably 0.5 μm or smaller. The PTFE particle content in this composition is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, and even more preferably 10 to 40% by mass. The PTFE particle content in this composition may be 10 to 60% by mass, 12 to 50% by mass, or 12 to 40% by mass, from the viewpoint of the tensile strength of the formed sheet. The specific surface area of ​​PTFE particles is 1 to 20 m². 2 / g is preferable. PTFE particles may be used individually or in combination of two or more types.

[0014] PTFE particles may contain other components besides PTFE, but particles consisting solely of PTFE are preferred. The PTFE content in the PTFE particles is preferably 90% by mass or more, and more preferably 99% by mass or more. Other components that may be included in PTFE particles include other resins or inorganic compounds, as described later.

[0015] F polymer is thermally meltable. A heat-meltable polymer refers to a polymer that, under a load of 49N, has a temperature at which the melt flow velocity is between 1 and 1000 g / 10 minutes. The melting temperature of the F polymer is preferably 200°C or higher, and more preferably 260°C or higher. The melting temperature of the F polymer is preferably 320°C or lower, and more preferably 310°C or lower.

[0016] The glass transition temperature of the F polymer is preferably 50°C or higher, and more preferably 75°C or higher. The glass transition temperature of the F polymer is preferably 150°C or lower, and more preferably 125°C or lower. The fluorine content of the F polymer is preferably 70% by mass or more, and more preferably 72-76% by mass. The surface tension of the F polymer is preferably 16 to 26 dyn / cm. The surface tension of the F polymer can be measured by placing a droplet of wetting index reagent (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) on a flat plate made of the F polymer. While F polymers with a high fluorine content exhibit excellent physical properties such as electrical properties, they tend to have low surface tension and low affinity with other components such as liquid compounds. However, since this composition contains a liquid compound with low surface tension, or water and a surfactant, it is presumed that the PTFE particles and F particles mix well and are uniformly distributed, suppressing the formation of aggregates.

[0017] The F polymer may be a polymer containing TFE units and other units in trace amounts. The F polymer is preferably a polymer containing TFE units and ethylene-based units, a polymer containing TFE units and propylene-based units, a polymer containing TFE units and PAVE-based units (a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene, also known as PFA), and a polymer containing TFE units and HFP-based units (a copolymer of tetrafluoroethylene and hexafluoropropylene, also known as FEP), with PFA and FEP being more preferred, and PFA being even more preferred. These polymers may further contain units based on other comonomers. PAVE is preferably CF2=CFOCF3, CF2=CFOCF2CF3, and CF2=CFOCF2CF2CF3 (hereinafter also referred to as PPVE), with PPVE being more preferred. The proportion of TFE units in the F polymer is less than 99.5 mol% of the total units, and preferably between 90 and 99.0 mol%.

[0018] The F polymer preferably has an oxygen-containing polar group. Examples of oxygen-containing polar groups include hydroxyl group-containing groups or carbonyl group-containing groups, and from the viewpoint of improving adhesion, the oxygen-containing polar group is preferably a carbonyl group-containing group. The hydroxyl group-containing group is preferably a group containing an alcoholic hydroxyl group, and -CF2CH2OH and -C(CF3)2OH are more preferred. The carbonyl group-containing groups are preferably carboxyl groups, alkoxycarbonyl groups, amide groups, isocyanate groups, carbamate groups (-OC(O)NH2), acid anhydride residues (-C(O)OC(O)-), imide residues (-C(O)NHC(O)-, etc.), and carbonate groups (-OC(O)O-), with acid anhydride residues being more preferred. The number of oxygen-containing polar groups in F polymer is 1 × 10⁶ carbon atoms in the main chain. 6 The number of oxygen-containing polar groups per polymer is preferably 10 to 5000, and more preferably 100 to 3000. The number of oxygen-containing polar groups in polymer F can be quantified by the polymer composition or by the method described in International Publication No. 2020 / 145133.

[0019] The oxygen-containing polar group may be included in the monomer-based units in the F polymer, or it may be included in the terminal groups of the main chain of the F polymer, with the former being preferred. Examples of the latter include an F polymer having an oxygen-containing polar group as a terminal group derived from a polymerization initiator, a chain transfer agent, etc., and an F polymer obtained by plasma treatment or ionization treatment of the F polymer. The monomers having a carbonyl group are preferably itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic acid anhydride (hereinafter also referred to as NAH), with NAH being more preferred. The F polymer is preferably a polymer containing TFE units and PAVE units and having carbonyl group-containing groups, and more preferably a polymer containing TFE units, PAVE units and units based on monomers having carbonyl group-containing groups, with these units present in the following proportions relative to the total number of units: 90-99 mol%, 0.99-9.97 mol%, and 0.01-3 mol%. A specific example of such an F polymer is the polymer described in International Publication No. 2018 / 16644.

[0020] The D50 of the F particles is preferably 0.1 μm or larger, more preferably 0.3 μm or larger, even more preferably greater than 0.3 μm, and particularly preferably 1 μm or larger. The D50 of the F particles is preferably 25 μm or smaller, more preferably 10 μm or smaller, and even more preferably 8 μm or smaller. The content of F particles in this composition is preferably 3 to 60% by mass, more preferably 5 to 60% by mass, even more preferably 10 to 50% by mass, and particularly preferably 12 to 40% by mass. The content of F particles in this composition may be 3 to 40% by mass, 3 to 20% by mass, or 3 to 16% by mass, from the viewpoint of the tensile strength of the formed sheet. The specific surface area of ​​F particles is 1 to 25 m². 2 / g is preferable. One type of F particle may be used, or two or more types may be used.

[0021] F particles are particles containing F polymer, and particles consisting of F polymer are preferred. F particles may contain PTFE in addition to the F polymer, and may also contain other resins or inorganic compounds. PTFE particles and F particles are distinguished by the presence or absence of the F polymer; particles containing the F polymer are classified as F particles. For example, particles containing both PTFE and the F polymer are F particles. The F particles may form a core-shell structure containing an F polymer as the core and another resin or inorganic compound as the shell, or they may form a core-shell structure containing an F polymer as the shell and another resin or inorganic compound as the core.

[0022] Other resins include aromatic polyesters, polyamide-imides, polyimides, and polybismaleimides. Examples of inorganic compounds include the same inorganic substances that may be contained in the inorganic particles described later, with silica and boron nitride being particularly preferred.

[0023] In this composition, the proportion of PTFE particles to the total of PTFE particles and F particles is preferably 40% by mass or more, and more preferably 45% by mass. The proportion of PTFE particles is preferably 80% by mass or less, and more preferably 70% by mass or less. When the proportion of PTFE particles is within the above range, the composition exhibits excellent uniformity, and the formation of aggregates is easily suppressed. Furthermore, molded products formed from this composition tend to have excellent electrical properties. In particular, if the proportion of PTFE particles is 40% by mass or more, the sheets formed from this composition tend to have excellent stretchability. Also, if the proportion of PTFE particles is 80% by mass or less, powder shedding during stretching of sheets formed from this composition tends to be easily suppressed.

[0024] The specified liquid compound is not particularly limited as long as it is a liquid compound with a surface tension of less than 72 dyn / cm. The surface tension of the specified liquid compound is preferably 60 dyn / cm or less, and more preferably 40 dyn / cm or less. The surface tension of the specified liquid compound may also be 10 dyn / cm or more. Note that a liquid compound is considered liquid at 25°C. The specific liquid compound is preferably a liquid compound that can be removed from the composition by means of heating, distillation, extraction, etc., and more preferably a liquid compound with a boiling point of 300°C or lower so that it can be easily removed by heating. In some embodiments, the specific liquid compound preferably comprises at least one selected from the group consisting of hydrocarbons and alcohols. In some embodiments, the specific liquid compound preferably comprises at least one selected from the group consisting of ethylene glycol, glycerin, and propylene glycol. Propylene glycol is more preferred as the specific liquid compound. Specific examples of the specified liquid compounds include hydrocarbons such as naphtha, white oil, liquid paraffin, toluene, xylene, hexane, n-decane, and dodecane; alcohols such as ethylene glycol, glycerin, and propylene glycol; and polyethylene glycol. One liquid compound may be used, or two or more may be used.

[0025] The mass content of the specific liquid compound in the first composition is less than the total mass content of PTFE particles and F particles, and the content of the specific liquid compound per 100 parts by mass of the total content of PTFE particles and F particles is preferably 98 parts by mass or less, more preferably 96 parts by mass or less. The content of the specific liquid compound is preferably 40 parts by mass or more, more preferably 60 parts by mass or more, and even more preferably 80 parts by mass or more. The first composition may contain, in addition to the specified liquid compound, other liquid compounds with a surface tension of 72 dyn / cm or more, or water. In this case, the proportion of the specified liquid compound in the total content of the specified liquid compound, other liquid compounds, and water is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more. The surface tension of the mixture of the specific liquid compound, other liquid compounds, and water in the first composition is preferably less than 72 dyn / cm, and more preferably satisfies the preferred surface tension of the specific liquid compound. The first composition preferably does not contain other liquid compounds and water.

[0026] The second composition uses water and a surfactant. The surface tension of the mixture of water and surfactant contained in the second composition is less than 72 dyn / cm. Preferably, the surface tension of the mixture of water and surfactant is 70 dyn / cm or less, and more preferably 60 dyn / cm or less. The surface tension of the mixture of water and surfactant may be 20 dyn / cm or more. Examples of surfactants include anionic surfactants, cationic surfactants, and nonionic surfactants. Among these, nonionic surfactants are preferred from the viewpoint of the composition exhibiting excellent uniformity and easily suppressing the formation of aggregates. Nonionic surfactants are preferably glycol-based surfactants, acetylene-based surfactants, silicone-based surfactants, or fluorine-based surfactants, with silicone-based surfactants being more preferred. One type of nonionic surfactant may be used, or two or more types may be used. When two types of nonionic surfactants are used, it is preferable that the nonionic surfactants be a silicone-based surfactant and a glycol-based surfactant.

[0027] Specific examples of nonionic surfactants include the "Futergent" series (manufactured by Neos Co., Ltd.), the "Surflon®" series (manufactured by AGC Seimi Chemical Co., Ltd.), the "Megafac®" series (manufactured by DIC Corporation), the "Unidyne" series (manufactured by Daikin Industries, Ltd.), "BYK-347", "BYK-349", "BYK-378", "BYK-3450", "BYK-3451", "BYK-3455", "BYK-3456" (manufactured by Bic Chemie Japan Co., Ltd.), "KF-6011", "KF-6043" (manufactured by Shin-Etsu Chemical Co., Ltd.), and the "Tergitol" series (manufactured by Dow Chemical Corporation, such as "Tergitol TMN-100X").

[0028] The water content in the second composition, by mass, is less than the total content of PTFE particles and F particles by mass. The water content per 100 parts by mass of the total content of PTFE particles and F particles is preferably 98 parts by mass or less, more preferably 96 parts by mass or less. The water content is preferably 40 parts by mass or more, more preferably 60 parts by mass or more, and even more preferably 80 parts by mass or more. The amount of surfactant in the second composition is not particularly limited as long as the surface tension of the mixture of water and surfactant is less than 72 dyn / cm. The amount of surfactant in the second composition per 100 parts by mass of water is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more. The amount of surfactant is preferably 15 parts by mass or less, more preferably 10 parts by mass or less. The second composition may contain, in addition to water, a specific liquid compound or other liquid compounds. In this case, the proportion of water in the total content of water, the specific liquid compound, and the other liquid compounds is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more. The surface tension of the mixture of water, surfactant, specific liquid compound, and other liquid compounds in the second composition is preferably less than 72 dyn / cm, and more preferably satisfies the preferred surface tension of the mixture of water and surfactant. The second composition preferably does not contain specific liquid compounds or other liquid compounds.

[0029] This composition may contain inorganic particles. This composition contains a specific liquid compound, or contains water and a surfactant, and the surface tension of the mixture of water and surfactant is less than 72 dyn / cm. As a result, the wettability of F particles is increased and the aggregation of F particles is easily broken down. This promotes the adhesion between inorganic particles and F particles, forming particles that can be considered as composite particles of both types of particles. As a result, the inorganic particles and F particles are uniformly mixed, and it is presumed that this composition has excellent dispersibility. Furthermore, it is presumed that a molded product with a uniform distribution of components, in which aggregation between inorganic particles or between F particles is suppressed, can be obtained from this composition. In addition, it is presumed that powder shedding of inorganic particles will be less likely to occur. The inorganic particles are preferably spherical, flaky, layered, needle-shaped, or plate-shaped, more preferably spherical, flaky, or layered, and even more preferably spherical or flaky. The spherical inorganic particles are preferably nearly spherical. Nearly spherical means that when the inorganic particles are observed with a scanning electron microscope (SEM), the ratio of the minor axis to the major axis is 0.7 or greater. Preferably, nearly spherical inorganic particles account for 95 percent or more of the total inorganic particles. The aspect ratio of the non-spherical inorganic particles is preferably 2 or greater, and preferably 5 or greater. The aspect ratio is preferably 10000 or less.

[0030] The inorganic particles may be hollow. In this case, the molded product obtained by molding this composition tends to have excellent electrical properties. The inorganic particles are particles containing at least one inorganic substance, preferably containing at least one selected from the group consisting of carbon, metal oxides, silica, and nitrides, and more preferably containing at least one selected from the group consisting of silica, boron nitride, and titanium dioxide. Specific examples of inorganic materials include carbon such as graphite, hard carbon, soft carbon, mesoporous carbon, and graphene; boron nitride, aluminum nitride, beryllia, silica, wollastonite, talc, steatite, cerium oxide, aluminum oxide, magnesium oxide, zinc oxide, barium titanate, lead zirconate titanate, lead titanate, zirconium oxide, and titanium oxide.

[0031] Furthermore, specific examples of inorganic materials include lithium-based oxides such as lithium nickel manganese cobalt oxide, lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium cobalt oxide, and lithium nickel cobalt aluminum oxide. From the viewpoint of reducing the dielectric constant and dielectric loss tangent of the molded product and improving low linear expansion properties, the inorganic particles are preferably particles containing silica or boron nitride. The silica is preferably amorphous silica. The boron nitride is preferably hexagonal boron nitride. Furthermore, from the viewpoint of improving dielectric constant, inorganic particles containing titanium dioxide or barium titanate are preferred.

[0032] When inorganic particles contain silica, it is preferable that the inorganic particles are hollow silica from the viewpoint of the electrical properties of the molded product. When inorganic particles contain nitrides, from the viewpoint of the electrical properties and low linear expansion of the molded product, the inorganic particles preferably contain boron nitride or aluminum nitride, and more preferably flaky boron nitride or columnar aluminum nitride. The flaky boron nitride may aggregate to form secondary particles.

[0033] The D50 of the inorganic particles is preferably 20 μm or less, and more preferably 10 μm or less. The D50 of the inorganic particles is preferably 0.01 μm or more, and more preferably 0.1 μm or more. The specific surface area of ​​inorganic particles is 1 to 20 m². 2 / g is preferable. The inorganic particle content in this composition is preferably 15% by mass or more, more preferably 20-80% by mass, and even more preferably 40-70% by mass, based on the total amount of the composition.

[0034] The surface of the inorganic particles may be surface-treated with a silane coupling agent. In this case, the affinity between the inorganic particles and the PTFE and F polymer is improved, the inorganic particles disperse more uniformly in the composition and molded article, and the inorganic particles are less likely to peel off the molded article. In addition, the molded article tends to have excellent electrical properties and low linear expansion. The preferred silane coupling agent is one having a functional group such as 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, or 3-isocyanatetopropyltriethoxysilane.

[0035] Specific examples of silica-containing particles include the "AdmaFine" series (manufactured by Admatex), the "SFP" series (manufactured by Denka), the "E-SPHERES" series (manufactured by Taiheiyo Cement), the "Silinax" series (manufactured by Nippon Steel Mining Co., Ltd.), and "E Coco's Examples include the "Feyer" series (manufactured by Emerson & Cumming) and the "Hydrophobic AEROSIL" series ("RX200," etc.) (manufactured by Nippon Aerosil Co., Ltd.). A specific example of particles containing zinc oxide is the "FINEX" series (manufactured by Sakai Chemical Industry Co., Ltd.). Specific examples of particles containing titanium dioxide include the "Typake®" series (manufactured by Ishihara Sangyo Co., Ltd.) and the "JMT" series (manufactured by Teika Co., Ltd.). A specific example of particles containing talc is the "SG" series (manufactured by Nippon Talc Co., Ltd.). A specific example of particles containing steatite is the "BST" series (manufactured by Nippon Talc Co., Ltd.). Specific examples of particles containing boron nitride include the "UHP" series (manufactured by Showa Denko Corporation) and the "GP" and "HGP" grades of the "Denka Boron Nitride" series (manufactured by Denka Corporation).

[0036] One type of inorganic particle may be used, or two or more types may be used. For example, silica particles, boron nitride particles, and titanium dioxide particles may be used in combination as inorganic particles. In this case, the content of silica particles, boron nitride particles, and titanium dioxide particles in relation to the total amount of inorganic particles is preferably 10-60% by mass, 10-60% by mass, and 5-40% by mass, in that order.

[0037] This composition may contain an aromatic polymer or its precursor (hereinafter collectively referred to as AR polymer). The AR polymer may be thermosetting or thermoplastic. Examples of AR polymers include aromatic polyimides, aromatic polyimide precursors which are polyamic acids or salts thereof, aromatic polyamideimides, aromatic polyamideimide precursors, aromatic polyetherimides, and aromatic polyetherimide precursors, with aromatic polyimides, aromatic polyimide precursors which are polyamic acids or salts thereof, aromatic polyamideimides, or aromatic polyamideimide precursors being more preferred.

[0038] The AR polymer content in this composition is preferably 0.1 to 20 parts by mass, and more preferably 1 to 10 parts by mass, per 100 parts by mass of the total of PTFE particles and F particles.

[0039] Specific examples of AR polymers include the "Yupia-AT" series (manufactured by Ube Industries), the "Neoprim®" series (manufactured by Mitsubishi Gas Chemical Company), the "Spixeria®" series (manufactured by Somar), the "Q-PILON®" series (manufactured by PI Technical Research Institute), the "WINGO" series (manufactured by Wingo Technology), the "Tomide®" series (manufactured by T&K TOKA), the "KPI-MX" series (manufactured by Kawamura Industries), and "HPC-1000" and "HPC-2100D" (both manufactured by Showa Denko Materials). In this composition, the AR polymer may be particulate or non-particulate, and is preferably non-particulate. In this composition, the AR polymer is preferably dissolved in a specific liquid compound or water. The AR polymer may be bonded to PTFE particles, F particles, or inorganic particles.

[0040] This composition may further contain other components such as pH adjusters, pH buffers, organic particles, organic pigments, metal soaps, lubricants, organic monomers, organic oligomers with a degree of polymerization of 50 or less, thixotropic agents, viscosity modifiers, defoamers, silane coupling agents, dehydrating agents, plasticizers, weathering agents, antioxidants, heat stabilizers, lubricants, antistatic agents, whitening agents, colorants, conductive agents, mold release agents, surface treatment agents, and flame retardants.

[0041] This composition may be a lump-like or clay-like composition in which the PTFE particles and F particles are bonded together but retain their particle shape, or in which the PTFE particles and F particles are bonded together but do not retain their particle shape.

[0042] The method for producing this composition is not particularly limited. The composition is preferably a kneaded product. Specifically, the composition is preferably a composition obtained by kneading PTFE particles, F particles, and a specific liquid compound or water. The first composition is preferably obtained by kneading PTFE particles, F particles, and a specific liquid compound. Furthermore, other components such as inorganic particles and AR polymers may be added when kneading the PTFE particles, F particles, and the specific liquid compound. In the method for producing the first composition, when kneading PTFE particles, F particles, a liquid compound, and other components as needed, examples include kneading the PTFE particles, F particles, a liquid compound, and other components as needed all at once, and kneading while sequentially adding the PTFE particles, F particles, a liquid compound, and other components as needed. The second composition is preferably obtained by kneading PTFE particles, F particles, water, and a surfactant. Alternatively, other components such as inorganic particles and AR polymers may be added when kneading the PTFE particles, F particles, water, and surfactant. In the method for producing the second composition, when kneading PTFE particles, F particles, water, surfactant, and other components as needed, methods include mixing the PTFE particles, F particles, water, surfactant, and other components as needed all at once, or mixing them while sequentially adding the PTFE particles, F particles, water, surfactant, and other components as needed. When producing the second composition, water and surfactant may be added individually, or they may be added as a mixture.

[0043] Specific methods of mixing include, for example, adding PTFE particles and F particles together to a specific liquid compound or a mixture of water and a surfactant and mixing them; adding PTFE particles and F particles sequentially to a specific liquid compound or a mixture of water and a surfactant while mixing; pre-mixing PTFE particles and F particles in powder form and mixing the resulting pre-mixture with a specific liquid compound or a mixture of water and a surfactant; and pre-mixing a mixture of PTFE particles and a specific liquid compound or a mixture of water and a surfactant, and a mixture of F particles and a specific liquid compound or a mixture of water and a surfactant separately, and then further mixing the two resulting mixtures. When mixing the components of this composition by adding them sequentially, the order in which each component is added is not particularly limited. It is preferable to pre-mix the PTFE particles and F particles before adding the specific liquid compound or the mixture of water and surfactant. Furthermore, if this composition contains inorganic particles as other components, it is more preferable to obtain a powder composition by mixing the F particles and inorganic particles, then adding and mixing the PTFE particles, and then adding the liquid compound or the mixture of water and surfactant to the powder composition and kneading it.

[0044] This composition, which contains carbon or lithium oxide, is preferably prepared from a powder composition obtained by mixing carbon or lithium oxide with F particles, and then adding and mixing PTFE particles. When mixing the PTFE particles, it is preferable to apply a strong shear force to promote fibrillation of the PTFE. Alternatively, carbon or lithium oxide may be added and mixed after adding and mixing the PTFE particles. Either carbon or lithium oxide may be used, or both carbon and lithium oxide may be used. Molded articles formed using such powder compositions have carbon or lithium-based oxides firmly and homogeneously retained, and are particularly useful as electrode members for lithium-ion capacitors and lithium secondary batteries, such as cathode electrode films.

[0045] During mixing, it is preferable to mix in such a way that the mass of the composition does not substantially change, and it is preferable to mix in a closed system. That is, it is preferable to mix in such a way that specific liquid compounds or water in the composition do not evaporate during mixing. As a result, each component is uniformly mixed, and a highly degassed composition is obtained.

[0046] For mixing, it is preferable to use a mixing tank and a mixer equipped with a single-shaft or multi-shaft mixing blade. Two or more mixing blades are preferable to achieve a high mixing effect. The mixing method can be either batch or continuous.

[0047] The kneaders used in batch mixing are preferably Henschel mixers, pressure kneaders, Banbury mixers, planetary mixers, colloid mills, rotating and revolving agitators, or thin-film swirling agitators, with planetary mixers or rotating and revolving agitators being more preferred. A planetary mixer has two rotating blades that rotate and revolve relative to each other, and has a structure that stirs and kneads the mixture in the mixing tank. As a result, there is less dead space in the mixing tank that the blades do not reach, reducing the load on the blades and allowing for highly kneaded compositions. A rotating and revolving agitator has a structure that agitates and kneads a mixture in a tank equipped with an agitation mechanism using rotation and revolution. Here, the rotational agitation mechanism is a mechanism that agitates and kneads the mixture by rotating the tank containing the mixture around a rotation axis. The direction of the rotation axis can be any direction relative to the tank. On the other hand, the revolutionary agitation mechanism is a mechanism that agitates and kneads the mixture by revolving the tank around a fixed point outside the tank containing the mixture. The rotation axis of the tank can be perpendicular, horizontal, or inclined with respect to the plane of revolution. A planetary mixer or a rotating / revolving agitator can mix PTFE particles and F particles while suppressing aggregation of the PTFE particles and F particles, wetting them with a specific liquid compound or a mixture of water and a surfactant, and allowing the PTFE particles and F particles to interact with each other to a high degree.

[0048] Mixing may be carried out while cooling or while heating. When heating is used, the composition becomes viscous, which puts a load on the mixing blades of the mixer, and as a result, the shear force on the PTFE and F polymer tends to increase. In particular, when multiple mixing blades are used, shear force is easily applied to the F polymer between the mixing blades themselves, or between the mixing blades and the mixing tank. As a result, when inorganic particles are added, not only are the PTFE particles, F particles and inorganic particles thoroughly mixed, but the PTFE particles, F particles or inorganic particles are also broken down, making it easier to form a composition with excellent dispersibility.

[0049] The PTFE particles may be fibrillated by kneading. In molded articles formed from this composition in which the PTFE particles are fibrillated, the PTFE readily supports F particles and inorganic particles, and the F particles and inorganic particles are less likely to peel off from the molded article. In addition, the PTFE becomes more likely to intertwine with the F polymer and inorganic particles, which tends to improve the toughness of the molded article.

[0050] The first method for producing the composition according to this disclosure is a method for obtaining the composition by kneading PTFE particles, F particles, and a specific liquid compound. In the composition, the mass-based content of the specific liquid compound is less than the mass-based total content of the PTFE particles and F particles. The second method for producing the composition in this disclosure is a method of obtaining the composition by kneading PTFE particles, F particles, water, and a surfactant. In the composition, the mass-based content of water is less than the mass-based total content of PTFE particles and F particles. Furthermore, the surface tension of the mixture of water and surfactant is less than 72 dyn / cm. Hereinafter, the first and second manufacturing methods will be collectively referred to as "this method." Details of the PTFE particles, F particles, specific liquid compounds, water, and surfactants in this Act are as described above in this composition. The details of the kneading method in this method are as described above in the method for producing this composition. In this Act, the composition may further contain other components such as inorganic particles and AR polymers. Details of the other components are as described above in this composition, and the method of mixing them is also as described above in this composition.

[0051] The method for manufacturing the sheet described herein is a method of obtaining a sheet by molding the composition. Hereinafter, the sheet obtained by molding the composition will also be referred to as the sheet. One method for molding the composition is to cast the composition. By casting the composition, the PTFE undergoes fibrillation, making it easier for the PTFE to support F particles and making it easier to obtain a sheet in which the F particles are less likely to peel off. Furthermore, if the composition contains inorganic particles, it is easier to obtain a sheet in which the inorganic particles are less likely to peel off. In addition, it is easier to obtain a sheet in which the electrical properties and toughness are excellent. Methods for casting this composition include press molding, extrusion molding, or calendering. Calendering refers to a method of rolling the composition by passing it between multiple rolls.

[0052] In this disclosure, the sheet may be obtained by removing the liquid compound or water from the composition and then molding it.

[0053] The casting of this composition may be carried out using one molding method, or by combining two or more molding methods. Furthermore, the casting may be carried out by repeating one molding method multiple times. For example, a base sheet obtained by extruding this composition may be further calendered and then cast, or a base sheet obtained by calendering this composition may be further calendered and then cast. In this case, it is easy to obtain a sheet of any thickness with excellent toughness and uniformity. Multiple rolls can be used in calendering, and it is preferable to use a combination of four rolls. Possible arrangements of the four rolls include I-type, S-type, inverted L-type, Z-type, and oblique Z-type.

[0054] The casting of this composition may be carried out with heating at a temperature below the melting point of PTFE, or without heating. After casting, the composition may be heated to remove specific liquid compounds or water. The sheet is obtained in the manner described above. The thickness of the sheet is, for example, 0.5 to 5 mm. This sheet may also be obtained by heating and firing it at a temperature above the melting point of PTFE.

[0055] A laminated sheet can be obtained by stacking two or more of the sheets obtained above. A laminated sheet can be obtained, for example, by stacking two or more of these sheets and rolling them. The number of layers in a laminated sheet is, for example, about 2 to 10 layers. From the viewpoint of strength between layers, it is preferable to stack and roll the sheets one by one.

[0056] Alternatively, the sheet may be folded and laminated. By folding and rolling the sheet, the sheet strength can be improved, and if the composition contains inorganic particles, the inorganic particles can be firmly fixed to the PTFE matrix. As a result, a laminated sheet with a high inorganic particle content and flexibility can be produced. Multiple laminated sheets can be stacked to create a laminated sheet with an even higher number of layers.

[0057] When creating a laminated sheet, it is desirable to change the rolling direction. For example, when obtaining a laminated sheet by rolling a second sheet on top of a first sheet, and then rolling a third sheet on top of that, it is preferable to change the direction in which the third sheet is rolled by 90 degrees from the direction in which the second sheet is rolled. By rolling while changing the direction in this way, the PTFE network extends both vertically and horizontally, improving the strength of the sheet and, if the composition contains inorganic particles, enabling strong fixation of the inorganic particles to the PTFE matrix. The resulting laminated sheet may be pressure-molded. Pressure molding can reduce the pores in the laminated sheet.

[0058] By heat-pressing this sheet or the laminated sheet obtained above onto a substrate, a laminate is obtained having a substrate layer and a polymer layer containing PTFE, F polymer, and, if necessary, inorganic particles or AR polymer.

[0059] Examples of substrates include metal substrates such as metal foils made of copper, nickel, aluminum, titanium, and their alloys; heat-resistant resin films such as polyimide, polyamide, polyetheramide, polyphenylene sulfide, polyallyl ether ketone, polyamide-imide, liquid crystalline polyester, and tetrafluoroethylene polymers; prepreg substrates, which are precursors to fiber-reinforced resin substrates; ceramic substrates such as silicon carbide, aluminum nitride, or silicon nitride; and glass substrates. The substrate can be planar, curved, or uneven. Furthermore, the substrate may be foil-like, plate-like, film-like, or fibrous. The surface roughness of the substrate with a ten-point average is preferably 0.01 to 0.05 μm.

[0060] The surface of the substrate may be surface-treated with a silane coupling agent or plasma-treated. Specific examples of silane coupling agents are as described above.

[0061] Methods of heat-pressure bonding include a method of sandwiching the substrate and the main sheet or laminated sheet between a pair of opposing hot plates and applying pressure, a method of passing the substrate and the main sheet or laminated sheet between a pair of opposing rolls, and a method of applying pressure to the substrate and the main sheet or laminated sheet by rolls on a hot plate. The temperature for heat bonding is preferably 200°C or higher, more preferably above the melting point of PTFE, and even more preferably 340°C or higher. A temperature of 400°C or lower is preferred. It is preferable to sinter the PTFE by heating during heat bonding. Heat bonding may also be performed using a hydraulic press. The heat-sealing pressure is preferably 1 to 40 MPa, and more preferably 10 to 30 MPa.

[0062] The heat-compression bonding may be performed under reduced pressure. In this case, it is preferable to perform the bonding at a vacuum level of 20 kPa or less, from the viewpoint of suppressing deterioration due to oxidation of the substrate and the sheet. In this case, it is preferable to perform the heat-compression bonding using a vacuum press. During heat sealing, it is preferable to either place a release film between the surface of the sheet and the heat plate or roll, or to surface treat the surface of the heat plate or roll with a release agent, in order to suppress adhesion of the sheet to the heat plate or roll.

[0063] The thickness of the release film is preferably 50 to 150 μm. Polyimide films are used as release films, with specific examples including "Apical NPI" (manufactured by Kaneka Corporation), "Kapton EN" (Toray DuPont), and "Upirex S" (manufactured by Ube Industries).

[0064] The sheet or laminated sheet may be heat-pressed onto only one surface of the substrate, or it may be heat-pressed onto both surfaces of the substrate. In the former case, a laminate is obtained having a substrate layer and a polymer layer on one surface of the substrate layer, and in the latter case, a laminate is obtained having a substrate layer and polymer layers on both surfaces of the substrate layer. Suitable examples of laminates include a metal-clad laminate having a metal foil and a polymer layer on at least one surface of the metal foil, and a polyimide film and a multilayer film having polymer layers on both surfaces of the polyimide film. The peel strength between the polymer layer and the substrate layer is preferably 10 to 100 N / cm. Furthermore, the substrate layer may be removed from the laminate to obtain a sheet containing PTFE and F polymer.

[0065] Molded products such as this sheet, laminated sheets, and laminates having laminated sheets are useful as antenna components, printed circuit boards, aircraft components, automobile components, sports equipment, food industry products, heat dissipation components, paints, cosmetics, etc. Specifically, these include wire insulation materials for aircraft and other applications, enameled wire insulation materials used in motors for electric vehicles and other applications, electrical insulation tapes, insulating tapes for oil drilling, oil transport hoses, hydrogen tanks, printed circuit board materials, separation membranes such as microfiltration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes and gas separation membranes, lithium-ion capacitors, electrode binders for lithium-ion secondary batteries and fuel cells, copy rolls, furniture, and automobile dashboards. DoIt is useful as a cover for home appliances, sliding members, tension ropes, wear pads, wear strips, tube lamps, test sockets, wafer guides, wear parts for centrifugal pumps, chemical and water supply pumps, tools such as shovels, files, drills and saws, boilers, hoppers, pipes, ovens, baking molds, chutes, racket strings, dies, toilets, container coverings, power devices, transistors, thyristors, rectifiers, transformers, power MOS FETs, CPUs, heat sinks, metal heat sinks, blades for wind turbines, wind power generation equipment and aircraft, housings for personal computers and displays, electronic device materials, interior and exterior parts for automobiles, sealing materials for processing machines and vacuum ovens that perform heat treatment under low oxygen conditions, plasma processing equipment, heat dissipation components in processing units such as sputtering and various dry etching equipment, and electromagnetic shielding. Examples of sliding members include load bearings, yaw bearings, sliding shafts, valves, bearings, bushings, seals, thrust washers, wear rings, pistons, slide switches, gears, cams, belt conveyors and food transport belts.

[0066] Although the present method, the method for manufacturing the sheet, and the method for manufacturing the laminated sheet and laminate have been described above, this disclosure is not limited to the configuration of the embodiments described above. For example, the present method, the method for manufacturing the sheet, the laminated sheet, and the method for manufacturing the laminate may have additional steps in the configuration of the above embodiment, or may be replaced by any steps that produce a similar effect. [Examples]

[0067] The embodiments of this disclosure will now be described in detail with reference to examples, but the embodiments of this disclosure are not limited to these examples.

[0068] 1. Preparation of each component [PTFE particles] PTFE particle 1: PTFE particles containing 99.9 mol% or more of TFE units (D50: 0.3 μm) [F particle] F particle 1: Contains TFE units, NAH units, and PPVE units in the following order: 97.9 mol%, 0.1 mol%, and 2.0 mol%, respectively, with carbonyl group-containing groups in the main chain having 1 × 10⁶ carbon atoms. 6 Particles of tetrafluoroethylene polymer (melting temperature: 300°C) with 1000 particles per unit (D50: 2.1 μm) [Liquid compounds] Liquid compound 1: Propylene glycol (surface tension: 35 dyn / cm) Liquid compound 2: Naphtha (surface tension: 20 dyn / cm) [Inorganic particles] Inorganic particle 1: Spherical silica (D50: 1 μm) [Surfactants] Surfactant 1: Silicone-based surfactant

[0069] 2. Manufacturing of the composition [Example 1] F particles 1 and inorganic particles 1 were placed in a mixer and mixed. Further, PTFE particles 1 were added and mixed to obtain a powder composition. The obtained powder composition and liquid compound 1 were placed in a rotary-orbiting agitator and kneaded while degassing at a rotation speed of 800 rpm and an orbital speed of 2000 rpm to obtain composition 1, which is a clay-like mixture containing 20 parts by mass of PTFE particles 1, 20 parts by mass of F particles 1, 60 parts by mass of inorganic particles 1, and 38 parts by mass of liquid compound 1. [Example 2] Composition 2 was obtained in the same manner as in Example 1, except that liquid compound 1 was replaced with liquid compound 2. [Example 3] Composition 3 was obtained in the same manner as in Example 1, except that 38 parts by mass of liquid compound 1 were replaced with 37 parts by mass of water and 1 part by mass of surfactant 1. The surface tension of water is 72 dyn / cm, and the surface tension of the mixture of 37 parts by mass of water and 1 part by mass of surfactant 1 was less than 72 dyn / cm. [Example 4] Composition 4 was obtained in the same manner as in Example 1, except that liquid compound 1 was replaced with water. [Example 5] Composition 5 was obtained in the same manner as in Example 1, except that the amount of PTFE particles 1 was 35 parts by mass and the amount of F particles 1 was 5 parts by mass. [Example 6] Composition 6 was obtained in the same manner as in Example 1, except that the amount of PTFE particles 1 was 15 parts by mass and the amount of F particles 1 was 25 parts by mass. The proportion of PTFE particles 1 to the total of PTFE particles 1 and F particles 1 is 50% by mass in compositions 1 to 4, 88% by mass in composition 5, and 38% by mass in composition 6.

[0070] 3. Manufacturing of the sheet Composition 1 was cast by passing it between a pair of rolling rolls to obtain a base sheet 1 with a thickness of 3 mm. The base sheet 1 was cast using an inverted L-shaped calender, and then heated in a 150°C oven for 30 minutes to remove the liquid compound 1, obtaining a sheet 1 with a thickness of 200 μm. Sheets 2 to 6 were obtained from compositions 2 to 6 in the same manner.

[0071] No oven contamination due to powder spillage was observed when manufacturing sheets 1, 2, 3, 5, and 6. However, oven contamination due to powder spillage was observed when manufacturing sheet 4. Furthermore, visual inspection of the surface of each sheet revealed that no aggregates were visible on the surface of sheets 1 and 6. Aggregates were visible on very small parts of the surface of sheets 2, 3, and 5. Aggregates were visible across the entire surface of sheet 4.

[0072] Furthermore, when sheets 1, 5, and 6 were subjected to stretching, sheets 1 and 5 exhibited a stretch strength of over 200%, while sheet 6 had a lower stretch strength. Also, no peeling occurred from sheet 1 during stretching, but peeling occurred from sheet 5.

[0073] The disclosures of Japanese Patent Application No. 2021-160035 and Japanese Patent Application No. 2021-193618 are incorporated herein by reference in their entirety. All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted as being incorporated by reference.

Claims

1. The material comprises particles containing polytetrafluoroethylene and particles containing a heat-meltable tetrafluoroethylene polymer, as follows (1): (1) Further comprising a liquid compound having a surface tension of less than 72 dyn / cm, wherein the mass-based content of the liquid compound is less than the mass-based total content of the particles containing polytetrafluoroethylene and the particles containing the heat-meltable tetrafluoroethylene polymer. Satisfying the conditions, The liquid compound comprises at least one selected from the group consisting of hydrocarbons and alcohols. A composition wherein the alcohol comprises at least one selected from the group consisting of ethylene glycol, glycerin, and propylene glycol.

2. The composition according to claim 1, wherein the melting temperature of the heat-meltable tetrafluoroethylene polymer is 200 to 320°C.

3. The composition according to claim 1, wherein the heat-meltable tetrafluoroethylene polymer has an oxygen-containing polar group.

4. The composition according to claim 1, wherein the proportion of particles containing polytetrafluoroethylene to the total of the particles containing polytetrafluoroethylene and the particles containing the heat-meltable tetrafluoroethylene polymer is 40 to 80% by mass.

5. The composition according to claim 2, wherein the proportion of particles containing polytetrafluoroethylene to the total of the particles containing polytetrafluoroethylene and the particles containing the heat-meltable tetrafluoroethylene polymer is 40 to 80% by mass.

6. The composition according to claim 3, wherein the proportion of particles containing polytetrafluoroethylene to the total of the particles containing polytetrafluoroethylene and the particles containing the heat-meltable tetrafluoroethylene polymer is 40 to 80% by mass.

7. The composition according to any one of claims 1 to 6, further comprising inorganic particles.

8. The composition according to claim 7, wherein the content of the inorganic particles is 15% by mass or more with respect to the total amount of the composition.

9. The composition according to any one of claims 1 to 6, further comprising an aromatic polymer or a precursor thereof.

10. The composition according to claim 8, further comprising an aromatic polymer or a precursor thereof.

11. The composition according to any one of claims 1 to 6, which is a kneaded product.

12. A method for producing a composition comprising particles containing polytetrafluoroethylene and particles containing a heat-meltable tetrafluoroethylene polymer, as described below (A): (A) Add a liquid compound having a surface tension of less than 72 dyn / cm to the composition and knead to obtain a composition in which the mass-based content of the liquid compound is less than the mass-based total content of the particles containing polytetrafluoroethylene and the particles containing the heat-meltable tetrafluoroethylene polymer. Satisfying the conditions, The liquid compound comprises at least one selected from the group consisting of hydrocarbons and alcohols. A method for producing a composition, wherein the alcohol comprises at least one selected from the group consisting of ethylene glycol, glycerin, and propylene glycol.

13. A method for producing a sheet, comprising molding a composition according to any one of claims 1 to 6 to obtain a sheet.