Method for producing viscoelastic body and viscoelastic body

Abstract

A method for manufacturing a viscoelastic material containing tetrafluoroethylene-based polymer particles with excellent dispersibility, uniformity, and other physical properties is provided. A method for manufacturing a dispersion with excellent liquid properties such as dispersion stability, uniformity, rheological properties, coatability, and storage stability obtained from the viscoelastic material is also provided, as well as the viscoelastic material itself. In the method for manufacturing the viscoelastic material, a thermally molten tetrafluoroethylene-based polymer powder is dry-pulverized to obtain particles of the tetrafluoroethylene-based polymer. The particles are then wet-mixed with a liquid composition containing at least one of an organic resin and inorganic particles to obtain a viscoelastic material containing the particles and at least one of the organic resin and inorganic particles.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a viscoelastic body comprising particles of a thermally fusible tetrafluoroethylene-based polymer, and to the viscoelastic body itself. Furthermore, this invention also relates to a method for manufacturing a dispersion using the said viscoelastic body. Background Technology

[0002] Polytetrafluoroethylene (PTFE) and other tetrafluoroethylene-based polymers possess excellent electrical properties, water and oil repellency, chemical resistance, and heat resistance, making them suitable for various industrial applications, such as printed circuit boards. Dispersions containing tetrafluoroethylene-based polymer particles are known as coating agents used to impart these properties to the surface of substrates.

[0003] In recent years, the rapid development of high-frequency signals has demanded materials with low dielectric constant, low dielectric loss tangent, and excellent insulation properties. Therefore, dispersions containing tetrafluoroethylene (PTFE) polymer particles have attracted considerable attention as materials with excellent dielectric constant and low dielectric loss tangent for forming the dielectric layer of printed circuit boards corresponding to high-frequency bands.

[0004] Patent Document 1 describes a dispersion of a resist ink containing tetrafluoroethylene-based polymer particles. Patent Document 2 discloses a dispersion containing PTFE particles and ceramic inorganic fillers.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-90923

[0008] Patent Document 2: Japanese Patent Application Publication No. 2016-194017 Summary of the Invention

[0009] The technical problem that the invention aims to solve

[0010] Due to their low surface tension, tetrafluoroethylene-based polymers exhibit extremely low affinity for other components. Therefore, dispersions containing tetrafluoroethylene-based polymer particles, other resins, and inorganic fillers suffer from problems such as thickening and particle aggregation. The liquid properties of the dispersions described in Patent Documents 1 and 2 are still insufficient.

[0011] After careful research, the inventors discovered that if the powder of a thermoplastic tetrafluoroethylene polymer is dry-pulverized and wet-mixed with a liquid composition containing organic resin or inorganic particles, a viscoelastic material with excellent dispersibility and uniformity can be obtained. Furthermore, a dispersion with excellent rheological properties such as dispersion stability, uniformity, viscosity and thixotropic ratio, as well as liquid properties such as coatability and storage stability can be obtained from this viscoelastic material.

[0012] The purpose of this invention is to provide a method for manufacturing a viscoelastic material containing tetrafluoroethylene-based polymer particles with excellent dispersibility, uniformity, and other physical properties, a method for manufacturing a dispersion with excellent dispersion stability, uniformity, rheology, coatability, and storage stability obtained from the viscoelastic material, and the viscoelastic material itself.

[0013] The present invention has the following aspects.

[0014] [1] A method for manufacturing a viscoelastic body, wherein a powder of a thermally molten tetrafluoroethylene polymer is dry-pulverized to obtain particles of the tetrafluoroethylene polymer, and the particles are wet-mixed with at least one of an organic resin and inorganic particles in the presence of a liquid substance to obtain a viscoelastic body comprising the particles and at least one of the organic resin and inorganic particles.

[0015] [2] As described in [1], the dry pulverization is carried out using at least one mixer selected from Henschel mixer, pressure kneader, Banbury mixer, rotary mixer, planetary mixer, ball mill, pulverizer, basket mill, sand mill, sand mill, DYNO mill, DISPERMAT disperser, SC mill, Spike mill, stirred mill, microemulsion disperser, nano-dispersant, Ultimaizer disperser, dissolver, disperser and high-speed impeller disperser.

[0016] [3] The manufacturing method described in [1] or [2], wherein the dry pulverization is carried out at a temperature below the glass transition temperature of the tetrafluoroethylene polymer.

[0017] [4] The manufacturing method described in any one of [1] to [3], wherein the wet mixing is carried out using at least one mixer selected from Henschel mixer, pressure kneader, Banbury mixer, rotary mixer, planetary mixer, ball mill, pulverizer, basket mill, sand mill, sand mill, DYNO mill, DISPERMAT disperser, SC mill, Spike mill, stirred mill, microemulsion disperser, nano-dispersant, Ultimaizer disperser, ultrasonic homogenizer, dissolver, disperser, high-speed impeller disperser and thin film gyratory high-speed mixer.

[0018] [5] The manufacturing method described in any of [1] to [4], wherein the wet mixing is carried out at a temperature above the glass transition temperature of the tetrafluoroethylene polymer.

[0019] [6] The manufacturing method described in any of [1] to [5], wherein the glass transition temperature of the tetrafluoroethylene polymer is 60 to 150°C.

[0020] [7] The manufacturing method described in any of [1] to [6], wherein the organic resin is a thermosetting resin.

[0021] [8] The manufacturing method described in any one of [1] to [7], wherein the organic resin is at least one aromatic resin selected from aromatic epoxy resin, phenolic resin, aromatic polyimide resin, aromatic polyimide resin precursor, aromatic polyamide-imide resin and aromatic polyamide-imide resin precursor.

[0022] [9] The manufacturing method described in any of [1] to [8], wherein the wet mixing is carried out by wet mixing the particles and the inorganic particles in the presence of a liquid substance, and then wet mixing the organic resin.

[0023]

[10] The manufacturing method described in any of [1] to [9], wherein the wet mixing is carried out by wet mixing the particles with a liquid composition comprising at least one of an organic resin and inorganic particles.

[0024]

[11] The manufacturing method described in

[10] wherein the liquid composition comprises at least an organic resin, the ratio of the mass of the organic resin to the mass of the tetrafluoroethylene polymer in the wet mixing is 0.1 or more, and the total content of the mass of the tetrafluoroethylene polymer and the mass of the organic resin in the viscoelastic body is 40% by mass or more.

[0025]

[12] A method for manufacturing a viscoelastic material, wherein a powder of a thermoplastic tetrafluoroethylene polymer is dry-pulverized to obtain particles of the tetrafluoroethylene polymer, and then the particles are mixed with a thermosetting resin varnish at a mass ratio of the thermosetting resin to the tetrafluoroethylene polymer of 0.1 or more to obtain a viscoelastic material containing the particles and the thermosetting resin.

[0026]

[13] A method for manufacturing a dispersion, wherein the viscoelastic body obtained by any one of the manufacturing methods described in [1] to

[12] is further diluted with water or a non-aqueous solvent to obtain a dispersion with a viscosity of 10,000 mPa·s or less.

[0027]

[14] A method for manufacturing a dispersion, wherein a viscoelastic body obtained by any one of the manufacturing methods described in [1] to

[12] is further mixed with an organic resin or inorganic particles to obtain a dispersion.

[0028]

[15] A viscoelastic body comprising particles of a thermosetting tetrafluoroethylene polymer and a thermosetting resin, wherein the mass ratio of the thermosetting resin to the mass of the tetrafluoroethylene polymer is 0.1 or more, and the total mass content of the tetrafluoroethylene polymer and the thermosetting resin is 40% by mass or more.

[0029] Invention Effects

[0030] According to the present invention, a method for manufacturing a viscoelastic material comprising at least one of a thermoplastic tetrafluoroethylene polymer particle and an organic resin and an inorganic particle can be provided, and a dispersion with excellent dispersibility and other liquid properties is formed from the viscoelastic material. Furthermore, the present invention also provides a viscoelastic material comprising at least one of a thermoplastic tetrafluoroethylene polymer particle and an organic resin and an inorganic particle in a predetermined proportion. Detailed Implementation

[0031] The following terms have the following meanings.

[0032] "Thermomelable tetrafluoroethylene polymers" refers to polymers containing tetrafluoroethylene (hereinafter also referred to as "TFE units")-based units, which are polymers with a melt flow rate of 1 to 1000 g / 10 minutes under a load of 49 N.

[0033] "The glass transition temperature (Tg) of a polymer" refers to the value determined by analyzing the polymer using the dynamic viscoelasticity assay (DMA).

[0034] "The melting temperature (melting point) of a polymer" refers to the temperature corresponding to the maximum value of the melting peak obtained by differential scanning calorimetry (DSC) of the polymer.

[0035] "D50" is the average particle size, which is the cumulative 50% diameter of the particle volume as determined by laser diffraction and scattering. That is, the particle size distribution of the particles is determined by laser diffraction and scattering, and a cumulative curve is obtained with the total volume of the particle group as 100%. The particle size at the point on the cumulative curve where the cumulative volume reaches 50% is the average particle size.

[0036] "D90" is the cumulative volume diameter of the particle, which is the cumulative 90% diameter of the particle's volume reference, calculated in the same way as "D50".

[0037] Unless otherwise specified, "viscosity" refers to the value obtained by measuring the dispersion using a Type B viscometer at room temperature (25°C) and a rotation speed of 30 rpm. The measurement was repeated three times, and the average of the three measurements was taken.

[0038] "Thixotropic ratio" is the value calculated by dividing the viscosity of a dispersion measured at 30 rpm by the viscosity measured at 60 rpm.

[0039] "Monomer-based unit" refers to a group of atoms based on a monomer formed through the polymerization of that monomer. The unit can be formed directly through a polymerization reaction, or it can be formed by processing the polymer to transform a portion of the unit into a unit with a different structure. Hereinafter, monomer-based unit will also be referred to as "monomer a unit".

[0040] The manufacturing method of the present invention (hereinafter also referred to as "this method") is to dry pulverize the powder of a thermally molten tetrafluoroethylene-based polymer (hereinafter also referred to as "F polymer") to obtain F polymer particles (hereinafter also referred to as "F particles"), and wet mix the F particles with at least one of an organic resin and inorganic particles in the presence of a liquid substance to obtain a viscoelastic material (hereinafter also referred to as "this viscoelastic material") containing F particles and at least one of an organic resin and inorganic particles.

[0041] This viscoelastic material exhibits excellent dispersibility and uniformity, and dispersions with excellent liquid properties, such as dispersion stability, can be obtained from it. The reasons for this are not yet clear, but can be inferred, for example, as follows.

[0042] Tetrafluoroethylene-based polymers have low surface tension and are prone to fibrillation, making their particles susceptible to aggregation or adhesion, and they are also in a state of easy denaturation. Therefore, if these particles are dispersed in a liquid and mixed with other materials such as organic resins or inorganic particles, aggregation or denaturation of the tetrafluoroethylene-based polymer particles will be induced, making it difficult to obtain a dispersion with sufficient liquid properties.

[0043] In this method, the powder, also known as the F-particle aggregate, is first dry-milled. Since the F polymer has excellent thermal melting properties and shape stability, such as resistance to fibrils, it can be highly pulverized while suppressing the deformation of the F polymer powder. That is, through dry milling, the F polymer powder becomes F particles in a state close to a primary particle aggregate, where aggregation or mutual adhesion is eliminated. If these F particles in this state are wet-mixed with at least one of an organic resin and inorganic particles in the presence of a liquid substance, the particulate F particles readily interact with the organic resin or inorganic particles. Furthermore, it is believed that wet mixing makes the mixture a viscoelastic body, thereby enhancing this interaction, forming a composite where the surface of the F particles is coated with organic resin or inorganic particles, or promoting the formation of a composition in which one material is highly dispersed in another. Through this mechanism, the dispersibility and uniformity of this viscoelastic body are excellent, thus yielding a dispersion with excellent liquid properties such as dispersion stability.

[0044] The melting temperature of polymer F is preferably above 200°C, more preferably above 260°C. The melting temperature of polymer F is preferably below 325°C, more preferably below 320°C.

[0045] The glass transition temperature of polymer F is preferably 60°C or higher, more preferably 75°C or higher. The glass transition temperature of polymer F is preferably 150°C or lower, more preferably 125°C or lower. If the glass transition temperature of polymer F is within this range, the shape stability of polymer F tends to be better, and the affinity of polymer F for the organic resin or inorganic particles described later is easily improved. Therefore, the dispersibility of polymer F in the resulting viscoelastic and dispersion tends to be better.

[0046] The fluorine content of polymer F is preferably 70% by mass or more, more preferably 72% to 76% by mass.

[0047] The surface tension of polymer F is preferably 16–26 mN / m. Furthermore, the surface tension of polymer F can be measured by placing a droplet of a wetting index reagent (manufactured by Wako Pure Chemical Industries, Ltd.) onto a plate made of polymer F.

[0048] The preferred polymers are PTFE, polymers containing TFE units and ethylene-based units, polymers containing TFE units and propylene-based units, polymers containing TFE units and perfluoro(alkyl vinyl ether)-based units (hereinafter also referred to as "PAVE units") (hereinafter also referred to as "PFA"), and polymers containing TFE units and hexafluoropropylene-based units (hereinafter also referred to as "FEP"), more preferably PFA and FEP, and even more preferably PFA. These polymers may also contain units based on other comonomers.

[0049] PAVE is preferably CF2=CFOCF3, CF2=CFOCF2CF3 and CF2=CFOCF2CF2CF3 (hereinafter also referred to as "PPVE"), and more preferably PPVE.

[0050] Polymer F preferably has oxygen-containing polar groups, more preferably has hydroxyl groups or carbonyl groups, and even more preferably has carbonyl groups. When polymer F has this functional group, the affinity of polymer F with the organic resins or inorganic particles described later, or the dispersion stability of the F particles, is easily improved. Furthermore, the adhesion of molded articles formed from this viscoelastic material tends to be better.

[0051] The hydroxyl group is preferably a group containing an alcohol hydroxyl group, more preferably -CF2CH2OH and -C(CF3)2OH.

[0052] The carbonyl group is preferably a carboxyl group, an alkoxy carbonyl group, an amide group, an isocyanate group, a carbamate group (-OC(O)NH2), an anhydride residue (-CO(O)OC(O)-), an imide residue (-C(O)NHC(O)-, etc.), and a carbonate group (-OC(O)O-), more preferably an anhydride residue.

[0053] When polymer F has oxygen-containing polar groups, the number of oxygen-containing polar groups in polymer F relative to 1×10 6 The number of carbon atoms in the main chain is preferably 10 to 5000, more preferably 100 to 3000. Furthermore, the number of oxygen-containing polar groups in the F polymer can be quantified by the composition of the polymer or by the method described in International Publication No. 2020 / 145133.

[0054] The oxygen-containing polar groups can be contained in the monomer-based units of the F polymer or in the terminal groups of the F polymer backbone, with the former being preferred. Examples of the latter include F polymers having oxygen-containing polar groups as terminal groups derived from polymerization initiators, chain transfer agents, etc., and F polymers obtained by plasma treatment or electrical discharge treatment of F polymers.

[0055] Monomers containing carbonyl groups are preferably itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"), with NAH being more preferred.

[0056] Polymer F is preferably a polymer containing TFE units and PAVE units, having a carbonyl group. More preferably, it is a polymer containing TFE units, PAVE units, and units based on monomers having carbonyl groups, wherein these units are in the following proportions relative to all units: 90–99 mol%, 0.99–9.97 mol%, and 0.01–3 mol%, respectively. A specific example of this polymer F is the polymer described in International Publication No. 2018 / 16644.

[0057] F polymer powder is an aggregate of F particles. As mentioned earlier, F particles are prone to agglomeration, so F polymer powder usually exists in the form of aggregates of F particles.

[0058] The average particle size D50 of the F particles constituting the F polymer powder is preferably 0.1 μm or more, more preferably more than 0.3 μm, and even more preferably 1 μm or more. The D50 of the F powder is preferably 25 μm or less, more preferably 10 μm or less, and even more preferably 8 μm or less.

[0059] The specific surface area of ​​the F particles constituting the F polymer powder is preferably 1 to 25 m². 2 / g.

[0060] The F particles constituting the F polymer powder can be one type or two or more types. The F polymer powder can be dry-milled in a mixture containing particles of other resins or inorganic particles. Examples of other resins include resin particles similar to the organic resins described later or inorganic particles similar to the inorganic particles described later. PTFE particles are preferred as other resin particles. These particles can be contained as a particle aggregate, i.e., powder, in which case the F polymer powder and PTFE powder can be milled while suppressing the denaturation of the PTFE particles. When both F particles and PTFE particles are included, the proportion of the former type of particle in the mixture is preferably 50% by mass or less, more preferably 25% by mass or less. Furthermore, the proportion is preferably 5% by mass or more, more preferably 10% by mass or more.

[0061] Furthermore, in this case, the D50 of the F particles is 1 to 4 μm, and the D50 of the PTFE particles is preferably 0.1 to 1 μm.

[0062] F particles are particles containing F polymers, preferably formed from F polymers.

[0063] F particles can also contain resins or inorganic compounds other than F polymers, forming a core-shell structure with F polymer as the core and resins or inorganic compounds other than F polymers as the shell, or vice versa.

[0064] Examples of resins other than F polymers include aromatic polyesters, polyamide-imide, polyimide, and maleimide.

[0065] Examples of inorganic compounds include silicon dioxide and boron nitride.

[0066] As mentioned earlier, the F polymer powder, which is an aggregate of F particles, is dry-milled to obtain F particles in a state close to that of a primary particle aggregate. Dry milling can be performed without adding liquid substances such as solvents by crushing the aggregate of F particles and eliminating the aggregation or adhesion of F particles. The shear force applied to the F polymer powder during dry milling is only sufficient to crush the F polymer powder into a state of individual particles.

[0067] Examples of apparatuses used for achieving the dry pulverization include at least one type of mixer selected from Henschel mixers, pressure kneaders, Banbury mixers, rotary mixers, planetary mixers, ball mills, pulverizers, basket mills, sand mills, sand grinders, DYNO mills, DISPERMAT dispersers, SC mills, Spike mills, stirred mills, microemulsion dispersers, nano-dispersants, Ultimaizer dispersers, dissolvers, dispersers, and high-speed impeller dispersers. By using these mixers, the F polymer powder can be highly pulverized into fine-particle F particles while suppressing the denaturation of the F polymer.

[0068] Dry pulverization can be performed using one type of mixer or multiple mixers. When using multiple mixers, different types of mixers can be used sequentially for dry pulverization, or the powder can be divided into multiple portions and then dry-pulverized separately using different mixers before being combined into one batch.

[0069] Among these mixers, a rotation-revolution mixer is preferred.

[0070] Dry milling can be performed at room temperature or simultaneously with heating or cooling, but it is preferred to perform it at a temperature below the glass transition temperature of the F polymer. By performing dry milling at a temperature below the glass transition temperature of the F polymer, it is possible to maintain the rigidity of the F particles while suppressing the softening of the F polymer. Therefore, the F polymer is less prone to denaturation, and the shape of the F particles can be maintained during milling.

[0071] Dry grinding is typically carried out at temperatures above 10°C. A constant temperature is not always necessary, as the temperature rises due to the heat generated by shearing. Alternatively, cooling can be implemented while maintaining a constant temperature to suppress temperature increases. Heating can also be used if required.

[0072] Dry pulverization is preferably carried out at a temperature 20°C lower than the glass transition temperature of polymer F, and more preferably at a temperature 30°C lower than the glass transition temperature of polymer F.

[0073] The dry grinding time is preferably 5 minutes or more, more preferably 10 minutes or more. The dry grinding can continue until the F polymer powder is broken down into individual F particles, typically for less than 20 hours.

[0074] Under the above conditions, the F polymer powder is dry-pulverized into F particles.

[0075] The D50 and specific surface area of ​​the dry-milled F particles can be the same as those of the F particles constituting the F polymer powder, but they can also be further micronized to change the specific surface area. The D50 of the dry-milled F particles is preferably 0.1 μm or more, more preferably more than 0.3 μm, and even more preferably 1 μm or more. The D50 of the dry-milled F particles is preferably 25 μm or less, more preferably 10 μm or less, and even more preferably 8 μm or less. The specific surface area of ​​the dry-milled F particles is preferably 1 to 25 m². 2 / g.

[0076] Except for D50 and specific surface area after dry grinding, it is the same as the F particles that make up the F polymer powder.

[0077] In this method, dry-milled F particles are wet-mixed with at least one of an organic resin and inorganic particles in the presence of a liquid substance. The liquid component is a component that is liquid at 25°C, and examples of solvents described later are possible. Furthermore, if the organic resin described later is liquid at 25°C, this organic resin can also be used as a liquid substance for wet mixing. From the perspective of the interaction between F particles and the organic resin or inorganic particles, it is preferable to use a liquid composition containing at least one of an organic resin and inorganic particles (hereinafter also referred to as the "mixed component") in the wet mixing process in the presence of the liquid substance.

[0078] In wet mixing, a liquid composition containing the mixing components can be prepared in advance and the F particles can be mixed with the liquid composition, or the F particles, the mixing components, and the solvent can be mixed. The liquid composition can be any one of the following: a composition containing the liquid organic resin as described above, a composition containing the mixing components and the solvent, or a composition containing the liquid organic resin and the solvent as described above. The mixing components can be any one or both of organic and inorganic resins.

[0079] The organic resin (hereinafter also referred to as "this organic resin"), which is one of the components of the mixture, is a resin that is different from F polymer.

[0080] The organic resin can be a thermosetting resin, a photocurable resin, or a thermoplastic resin, but a thermosetting resin is preferred. When the organic resin is a thermosetting resin, during wet mixing, the thermosetting resin partially cures and thickens due to the heat generated during mixing while mixing with the F particles. Therefore, the surface of the F particles is effectively covered by the thermosetting resin and easily stabilized, thus easily obtaining this viscoelastic material and the dispersion described later with excellent uniformity and dispersibility.

[0081] Furthermore, by performing wet mixing at a temperature above the glass transition temperature of the F polymer, the thermosetting resin can be partially cured while the F polymer is softened. Therefore, it is easy to obtain this viscoelastic material with high interaction between F particles and thermosetting resin, and excellent uniformity and dispersibility.

[0082] Examples of organic resins include liquid crystal aromatic polyesters, polyacrylate resins and other polyester resins, amide resins, imide resins, epoxy resins, maleimide resins, polyurethane resins, polyphenylene ether resins, polyphenylene ether resins, polyphenylene sulfide resins, polyolefin resins, polycarbonate resins, polyacetal resins, aromatic resins, and fluoropolymers other than F polymers.

[0083] Aromatic resins are preferred as the organic resin used in this study. When the organic resin is an aromatic resin, it readily interacts with the F polymer, thus improving the uniformity and dispersibility of the viscoelastic material.

[0084] Examples of aromatic resins include aromatic epoxy resins, phenolic resins, aromatic polyimide resins, precursors of aromatic polyimide resins, aromatic polyamide-imide resins, and precursors of aromatic polyamide-imide resins. Preferably, at least one aromatic resin is selected from aromatic epoxy resins, phenolic resins, aromatic polyimide resins, precursors of aromatic polyimide resins, aromatic polyamide-imide resins, and aromatic polyamide-imide resins.

[0085] Examples of aromatic epoxy resins include biphenyl phenolic varnish epoxy resins, phenolic phenolic varnish epoxy resins, o-cresol phenolic varnish epoxy resins, p-tert-butylphenol phenolic varnish epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, bisphenol S type epoxy resins, naphthalene type epoxy resins, triphenol type epoxy resins, tert-butylcatechol type epoxy resins, aminophenol type epoxy resins, biphenyl type epoxy resins, biphenyl aryl alkyl type epoxy resins, and benzene aryl alkyl type epoxy resins. These epoxy resins can be solid, semi-solid, or liquid.

[0086] In addition, "solid state" refers to a solid state at 40°C, "semi-solid state" refers to a solid state at 20°C and a liquid state at 40°C, and "liquid state" refers to a liquid state at 20°C.

[0087] Examples of phenolic resins include phenolic varnish resins, alkylphenolic varnish resins, bisphenol A phenolic varnish resins, dicyclopentadiene-type phenolic resins, Xylok-type phenolic resins, terpene-modified phenolic resins, cresol or naphthol resins, polyvinylphenol resins, phenolic resins containing an α-naphthol backbone, cresol phenolic varnish resins containing a triazine backbone, biphenyl aryl alkyl-type phenolic resins, and Xylok-type phenolic varnish resins. These phenolic resins can be used as curing agents for thermosetting resins such as aromatic epoxy resins.

[0088] Examples of precursors for aromatic polyimide resins include polyamic acid and its salts, which are polymerized from tetracarboxylic dianhydrides and diamines.

[0089] Examples of aromatic polyamide-imide resins or precursors thereof include polyamide-imide resins or precursors thereof obtained by reacting at least one of a diisocyanate or a diamine with a tricarboxylic acid anhydride.

[0090] Examples of tetracarboxylic dianhydrides include pyromellitic dianhydride and biphenyltetracarboxylic dianhydride. Examples of diamines include phenylenediamine, 3,3'-dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenyl ether.

[0091] Examples of diisocyanates include 4,4'-diphenylmethane diisocyanate, xylene diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, and 3,3'-diphenylmethane diisocyanate.

[0092] Specific examples of aramid resins, aramid resins, or their precursors include the "UPIA-AT" series (manufactured by Ube Industries, Ltd.), the "Neopulim" series (manufactured by Mitsubishi Gas Chemical Co., Ltd.), the "SPIXAREA" series (manufactured by Somalon Corporation), the "Q-PILON" series (manufactured by PI Technology Research Institute), the "WINGO" series (manufactured by WINGO Technology Co., Ltd.), the "Tohmide" series (manufactured by Dick Toka Co., Ltd.), the "KPI-MX" series (manufactured by Kawamura Sangyo Co., Ltd.), "HPC-1000", and "HPC-2100D" (both manufactured by Showa Denko Materials Co., Ltd.).

[0093] Alternatively, aromatic resins can also be modified aromatic resins having a carboxyl group and an intramolecular olefinic unsaturated double bond derived from (meth)acryloyloxy. In this specification, (meth)acryloyloxy is a general term for acryloyloxy, methacryloyloxy, and both.

[0094] This modified aromatic resin is a photosensitive resin with good photocurability and developability, and it is also an alkali-soluble resin. As the modified aromatic resin, a phenolic resin containing carboxyl groups is preferred, and a carboxyl-containing phenolic resin is more preferably obtained by reacting a multifunctional phenolic varnish-type epoxy resin or similar multifunctional phenolic resin with (meth)acrylic acid, followed by the addition of an organic polyacid anhydride to the hydroxyl groups present in the side chain.

[0095] The number-average molecular weight (Mn) of the aromatic resin is preferably 5000–50000, and the acid value of the aromatic resin is preferably 20–100 mg / KOH. Furthermore, the acid value of the aromatic resin is determined by titrating a mixed solution of 0.5 g of the aromatic resin, 0.15 g of 1,4-diazabicyclo[2.2.2]octane, 60 g of N-methyl-2-pyrrolidone, and 1 mL of deionized water using a potentiometric titration apparatus with a 0.05 mol / L potassium hydroxide ethanol solution. Additionally, when the aromatic resin has an anhydride group, the acid value after ring-opening of the anhydride group is taken as the acid value of the aromatic resin.

[0096] This organic resin can also be a cyanate ester resin. Examples of cyanate ester resins include phenolic varnish-type cyanate ester resins, alkylphenolic varnish-type cyanate ester resins, dicyclopentadiene-type cyanate ester resins, bisphenol A-type cyanate ester resins, bisphenol F-type cyanate ester resins, and bisphenol S-type cyanate ester resins. Additionally, partially triazine-modified prepolymers can also be used. These cyanate ester resins can be used as curing agents for thermosetting resins such as the aforementioned aromatic epoxy resins.

[0097] The organic resin can also be a non-thermally meltable tetrafluoroethylene-based polymer, preferably PTFE. PTFE is preferably in granular form, more preferably in granular form with a D50 of 0.1 to 1 μm. When the organic resin is PTFE, it is preferable to use an aqueous dispersion of PTFE particles, and more preferably to use a liquid composition containing an aqueous dispersion of PTFE particles.

[0098] The organic resin constituting this organic resin may be one type or two or more types. When this organic resin includes a thermosetting resin, it is used in conjunction with this organic resin and an organic resin serving as a curing agent for said thermosetting resin.

[0099] When one of the mixed components is this organic resin, if the total mass including the liquid substance, this organic resin, and, if any, the inorganic particles described later, is set to 100% by mass, then its content is preferably 10% by mass or more, more preferably 20% by mass or more. Its content is preferably 80% by mass or less, more preferably 60% by mass or less.

[0100] The inorganic particles (hereinafter also referred to as "the inorganic particles") that are one of the components of the mixture are preferably spherical, needle-like, fibrous or plate-like, more preferably spherical, scale-like or layered, and even more preferably spherical or scale-like.

[0101] The spherical inorganic particles are preferably approximately spherical. "Approximately spherical" means that, when observed using a scanning electron microscope (SEM), the proportion of inorganic particles with a minor axis to major axis ratio of 0.7 or higher is greater than 95%.

[0102] The aspect ratio of the non-spherical inorganic particles is preferably 2 or higher, and more preferably 5 or higher. The aspect ratio is preferably 10000 or lower.

[0103] The inorganic particles are preferably carbon fillers, inorganic nitride fillers, or inorganic oxide fillers, more preferably carbon fiber fillers, boron nitride fillers, aluminum nitride fillers, beryllium oxide fillers, silica fillers, wollastonite fillers, talc fillers, cerium oxide fillers, aluminum oxide fillers, magnesium oxide fillers, zinc oxide fillers, or titanium dioxide fillers, and even more preferably boron nitride fillers or titanium dioxide fillers.

[0104] The D50 of this inorganic particle is preferably 20 μm or less, more preferably 10 μm or less. The D50 is preferably 0.01 μm or more, more preferably 0.1 μm or more.

[0105] The specific surface area of ​​this inorganic particle is preferably 1-20 m². 2 / g.

[0106] The surface of these inorganic particles can be treated with silane coupling agents.

[0107] The preferred silane coupling agents are silane coupling agents with functional groups, such as 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and 3-isocyanatepropyltriethoxysilane.

[0108] Specific examples of silica fillers include the "admafin" series (manufactured by Adma Corporation), the "SFP" series (manufactured by Nippon Denka Co., Ltd.), and the "E-SPHERES" series (manufactured by Pacific Cement Co., Ltd.).

[0109] As a specific example of zinc oxide filler, the "FINEX" series (manufactured by Sakai Chemical Industry Co., Ltd.) can be cited.

[0110] Specific examples of titanium dioxide fillers include the "TIPAQUE" series (manufactured by Ishihara Sangyo Co., Ltd.) and the "JMT" series (manufactured by Teika Co., Ltd.).

[0111] As a specific example of talc fillers, the "SG" series (manufactured by Japan Talc Corporation) can be cited.

[0112] As a specific example of block talc filler, the "BST" series (manufactured by Japan Talc Co., Ltd.) can be cited.

[0113] Specific examples of boron nitride fillers include the "UHP" series (manufactured by Showa Denko Co., Ltd.), the "GP" and "HGP" grades of the "Denka Boron Nitride" series (manufactured by Nippon Denka Co., Ltd.).

[0114] When one of the mixed components is this inorganic particle, if the total mass including the liquid substance, this inorganic particle, and, if present, this organic resin is set as 100% by mass, then its content is preferably 10% by mass or more, more preferably 20% by mass or more. Its content is preferably 80% by mass or less, more preferably 60% by mass or less.

[0115] Preferably, a liquid composition comprising at least one of the organic resin and the inorganic particles is used. "Liquid" refers to a state with a viscosity of less than 10000 mPa·s at 25°C, and may or may not contain a solvent.

[0116] Examples of solvent-free liquid compositions include, for instance, liquid compositions containing the liquid form of the organic resin and being solvent-free.

[0117] When a solvent is used as the liquid substance, the solvent is a compound that is liquid at atmospheric pressure and 25°C, preferably a compound with a boiling point of 50–240°C. One or more solvents may be used. When using two solvents, it is preferable that the two solvents are miscible with each other.

[0118] The solvent can be either water or a non-aqueous solvent. Examples of non-aqueous solvents include amides, ketones, esters, (meth)acrylates, and diols.

[0119] In this specification, (meth)acrylate is a general term for acrylate, methacrylate, and both.

[0120] When water or a non-aqueous solvent is used as the liquid substance, F particles can interact with the organic resin or inorganic particles through water or a non-aqueous solvent, easily obtaining the viscoelastic material with excellent uniformity and dispersibility.

[0121] Examples of amides include N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, N,N-diethylformamide, hexamethylphosphoric triamine, and 1,3-dimethyl-2-imidazolinone.

[0122] Examples of ketones include acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl n-pentanone, methyl isopentanone, 2-heptanone, cyclopentanone, cyclohexanone, and cycloheptanone.

[0123] Examples of esters include methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethyl 3-ethoxypropionate, γ-butyrolactone, and γ-valerolactone.

[0124] The viscosity of the (meth)acrylate is preferably 1 to 1000 mPa·s, more preferably 5 to 300 mPa·s.

[0125] The molecular weight of the (meth)acrylate is preferably 100 to 1000.

[0126] The (meth)acrylate is preferably a polyfunctional (meth)acrylate or a mono(meth)acrylate having a hydroxyl group or an oxyalkylene group, more preferably a polyfunctional (meth)acrylate.

[0127] As the polyfunctional (meth)acrylate, di(meth)acrylate, alkylene glycol di(meth)acrylate, glycerol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, di(trimethylol)propane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, erythritol tetra(meth)acrylate and dierythritol hexa(meth)acrylate are preferred.

[0128] The polyfunctional (meth)acrylate can also be obtained as a commercial product. Specifically, examples include the <NK ester> series such as "A-DPH" (dipentaerythritol hexaacrylate, 7500 mPa·s (25 °C)) and "A-9550" (dipentaerythritol hexaacrylate, 6500 mPa·s (25 °C)) manufactured by Shin-Nakamura Chemical Co., Ltd.

[0129] The glycol compound is preferably liquid at 25 °C.

[0130] As the liquid glycol compound, glycol derivatives such as glycol, ether of glycol, ester of glycol and amide of glycol can be cited.

[0131] As suitable liquid glycol compounds, 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 can be cited.

[0132] Diol liquid compounds are also available commercially, including, for example, "Tergitol TMN-100X" (manufactured by Dow Chemical Company); "Lutensol TO8", "Lutensol XL70", "Lutensol XL80", "Lutensol XL90", "Lutensol XP80", and "Lutensol M5" (manufactured by BASF); "Newcol 1305", "Newcol1308FA", and "Newcol 1310" (manufactured by Nippon Emulsifier Co., Ltd.); "LEOCOL TDN-90-80" and "LEOCOLSC-90" (manufactured by Lion Specialty Chemicals Co., Ltd.); and "Palmless NOB-25", "Palmless NOB-30", and "Palmless NOB-50" (manufactured by Three Palms P&A).

[0133] When the liquid composition contains the solvent, the F particles can interact highly with the organic resin or the inorganic particles through the solvent, easily obtaining this viscoelastic with excellent uniformity and dispersibility.

[0134] The liquid substance or the liquid composition may also contain nonionic surfactants.

[0135] Nonionic surfactants are preferably glycol-based, acetylene-based, silicone-based, or fluorinated surfactants, with silicone-based surfactants being more preferred. One or more nonionic surfactants may be used. When using two nonionic surfactants, silicone-based and glycol-based surfactants are preferred.

[0136] Specific examples of nonionic surfactants include the "Ftergent" series (manufactured by Neos Corporation), the "Surflon" series (manufactured by AGC Seimei Chemical Co., Ltd.), the "MEGA FACE" 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" (BYK Chemicals Japan Co., Ltd.), "KF-6011", and "KF-6043" (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0137] When the liquid substance or liquid composition contains a nonionic surfactant, the content of the nonionic surfactant is preferably 1 to 15% by mass.

[0138] Furthermore, when the thermosetting resin is used as a component of the mixture, the mixture may contain a non-resin curing agent.

[0139] The combination of the curing agent and the thermosetting resin can be appropriately selected. If the F polymer has the carbonyl group, the curing agent can undergo a thermosetting reaction with the F polymer.

[0140] Examples of curing agents include amines, imidazoles, phenols, acid anhydrides, and compounds with maleimide groups.

[0141] When the thermosetting resin is used as a component in the mixture, the curing agent is preferably selected according to the standard that the curing initiation temperature of the curing resin reaches 120°C to 200°C. The curing initiation temperature is the temperature at which the curing resin initially shows heat when heated, as determined by differential scanning calorimetry (DSC).

[0142] Examples of amines include alkylene diamines, polyalkylene polyamines, aliphatic polyamines with aromatic rings, and their addition compounds, as well as isophorone diamine, 1,3-di(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane, norbornene diamine, 1,2-diaminocyclohexane, laromin, and other alicyclic polyamines and their addition compounds.

[0143] Specific examples of amines include the "FujiCure FXR" series (all manufactured by Fuji Chemical Industries, Ltd.), the "Acamine" series, the "Sunmide" series (all manufactured by Air Products Japan Ltd.), jERCure113 (manufactured by Mitsubishi Chemical Corporation), and Laromin C-260 (manufactured by BASF).

[0144] Examples of imidazoles include 2-methylimidazolium, 4-methyl-2-ethylimidazolium, 2-phenylimidazolium, 4-methyl-2-phenylimidazolium, 1-benzyl-2-methylimidazolium, 2-ethylimidazolium, 2-isopropylimidazolium, 1-cyanoethyl-2-methylimidazolium, 1-cyanoethyl-2-ethyl-4-methylimidazolium, 1-cyanoethyl-2-undecylimidazolium, azazine compounds of imidazolium, isocyanurates of imidazolium, hydroxymethyl forms of imidazolium, or addition compounds of these substances.

[0145] Examples of phenols include hydroquinone, resorcinol, and bisphenol A.

[0146] Examples of acid anhydrides include phthalic anhydride, hexahydrophthalic anhydride, methylnadic anhydride, and benzophenone tetracarboxylic acid.

[0147] Examples of compounds having a maleimide group include 4,4'-bismaleimide diphenylmethane, bismaleimide benzene, m-phenylene bismaleimide, 3,3'-dimethyl-5,5'-dimethyl-4,4'-bismaleimide diphenylmethane, 4-methyl-1,3-phenylene bismaleimide, (1,6-bismaleimide-2,2,4-trimethyl)hexane, their oligomers, and diamine condensates having a maleimide skeleton.

[0148] The viscoelastic material is obtained by wet mixing the F particles with the mixture components. In the wet mixing, shearing is applied to ensure that the F particles are uniformly mixed with the organic resin or inorganic particles that are the mixture components.

[0149] As an apparatus for wet mixing, the mixers exemplified in the dry pulverization process can also be cited. In addition to the mixers mentioned above, ultrasonic homogenizers and thin-film gyratory high-speed mixers can also be used for wet mixing. Wet mixing is preferably carried out using at least one mixer selected from the following: Henschel mixer, pressure kneader, Banbury mixer, rotary mixer, planetary mixer, ball mill, pulverizer, basket mill, sand mill, sand grinder, DYNO mill, DISPERMAT disperser, SC mill, Spike mill, stirred mill, microemulsion disperser, nano-dispersant, Ultimaizer disperser, ultrasonic homogenizer, dissolver, disperser, high-speed impeller disperser, and thin-film gyratory high-speed mixer. Using these mixers allows for efficient mixing of F particles with organic resins or inorganic particles while suppressing F polymer denaturation, and is therefore preferred.

[0150] Wet mixing can be performed using one type of mixer or multiple types of mixers. When using multiple mixers, wet mixing can be performed sequentially using different types of mixers, or wet mixing can be performed in several separate steps using different mixers and then combined into one mixture.

[0151] Among these mixers, the rotary mixer is preferred.

[0152] Wet mixing can be carried out at room temperature or simultaneously with heating or cooling, but it is preferred to do so at a temperature above the glass transition temperature of the F polymer. Wet mixing at a temperature above the glass transition temperature of the F polymer softens the F polymer, reducing the rigidity of the F particles and enhancing interactions with organic resins or inorganic particles, thereby improving the dispersibility and uniformity of the resulting viscoelastic.

[0153] Wet mixing is typically performed at temperatures above 10°C. A constant temperature is not required, as the temperature may rise due to heat generated by shearing. Alternatively, cooling can be implemented to suppress temperature rise while maintaining a constant temperature. Heating may be used if necessary. Wet mixing is preferably performed at a temperature above the glass transition temperature of the polymer F, more preferably at a temperature 10°C higher than the glass transition temperature of the polymer F. Wet mixing is preferably performed at temperatures below 120°C, more preferably below 100°C.

[0154] The wet mixing time is preferably 5 minutes or more, more preferably 10 minutes or more. The point at which the load applied to the mixer reaches a constant value can be regarded as the end point of wet mixing, which is usually less than 20 hours.

[0155] Wet surfactants or curing agents can also be added during wet mixing.

[0156] When wet mixing of F particles, organic resin, and inorganic particles, it is preferable to wet mix the F particles and inorganic particles first, followed by wet mixing of the organic resin. In this case, it is easier to suppress the viscosity increase and foaming properties of the viscoelastic material and the resulting dispersion.

[0157] The viscosity of this viscoelastic body, as determined by capillary rheology, is preferably greater than 100 Pa·s, more preferably 1000 Pa·s or more, and even more preferably 3000 Pa·s or more. The viscosity of this viscoelastic body, as determined by capillary rheology, is preferably 50000 Pa·s or less, more preferably 10000 Pa·s or less, and even more preferably 8000 Pa·s or less. Furthermore, the viscosity determined by capillary rheology is achieved using a capillary with a length of 10 mm and a radius of 1 mm, at a furnace diameter of 9.55 mm, a force sensor capacity of 2 t, a temperature of 25°C, and a 100-second timeframe. -1 The value of the shear rate was measured.

[0158] The compressive modulus of this viscoelastic material is preferably 0.4 MPa or more, more preferably 0.5 MPa or more. The compressive modulus of this viscoelastic material is preferably 1 MPa or less, more preferably 0.8 MPa or less. The compressive modulus is the maximum load when this viscoelastic material is compressed at 1 mm / min using a Strograph (manufactured by Toyo Seiki Co., Ltd.).

[0159] If the viscosity and compressive modulus of the viscoelastic body, as determined by capillary rheology, are within the above-mentioned ranges, then the interaction between the F particles and the organic resin or the inorganic particles is enhanced, and therefore preferred.

[0160] When this viscoelastic material contains the inorganic particles, with the mass of polymer F being 1, the mass ratio of polymer F to the inorganic particles is preferably 0.05 or more, more preferably 0.1 or more. The aforementioned ratio is preferably 20 or less, more preferably 10 or less, and even more preferably 1 or less.

[0161] When this viscoelastic material contains this organic resin, with the mass of polymer F being 1, the mass ratio of polymer F to this organic resin is preferably 0.05 or more, more preferably 0.1 or more. The above ratio is preferably 20 or less, more preferably 10 or less, and even more preferably 1 or less.

[0162] The amount of solids in this viscoelastic material refers to the total amount of substances constituting the solids in the molded article formed from this viscoelastic material or the dispersion described later. For example, in the case where this viscoelastic material contains polymer F and the organic resin and / or inorganic particles, the total content of these components is the amount of solids in this viscoelastic material.

[0163] The solid content in this viscoelastic material is preferably 20% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. The solid content is 100% by mass or less, more preferably 80% by mass or less.

[0164] In this viscoelastic material, the content of F particles in the solid component is preferably 20% by mass or more, more preferably 40% by mass or more. Furthermore, the content of F particles is preferably 90% by mass or less, more preferably 80% by mass or less.

[0165] When this viscoelastic material contains inorganic particles, the content of these inorganic particles in the solid component is preferably 10% by mass or more, more preferably 20% by mass or more. The content of these inorganic particles is preferably 80% by mass or less, more preferably 60% by mass or less.

[0166] When this viscoelastic material contains the organic resin, the content of the organic resin in the solid component is preferably 10% by mass or more, more preferably 20% by mass or more. The content of the organic resin is preferably 80% by mass or less, more preferably 60% by mass or less.

[0167] When the viscoelastic material comprises both the inorganic particles and the organic resin, it is preferable that at least one of the inorganic particles or the organic resin is within the above-mentioned range, and more preferably both are within the above-mentioned range.

[0168] For example, the contents of F particles, inorganic particles, and organic resin in the solid component are preferably such that, with 100% by mass of the solid component, the content of F particles is 40% by mass or more, the content of inorganic particles is 10% by mass or more, or the content of organic resin is 10% by mass or more. More preferably, with 100% by mass of the solid component, the content of F particles is 40% by mass or more, the content of inorganic particles is 10% by mass or more, and the content of organic resin is 10% by mass or more.

[0169] For example, the preferred ratio of F particles to inorganic particles and organic resin in this viscoelastic material is such that the content of F particles is 1, then the content of inorganic particles is 0.05 to 1, or the content of organic resin is 0.05 to 1. More preferably, the content of F particles is 1, then the content of inorganic particles is 0.05 to 1, and the content of organic resin is 0.05 to 1.

[0170] To obtain this viscoelastic material with the viscosity and composition within the above range, the necessary components may be added during the wet mixing process, depending on the composition of the mixing components.

[0171] When the viscosity and composition are within the specified range, the dispersibility, uniformity, and other liquid properties of this viscoelastic material tend to improve.

[0172] This viscoelastic material may further contain thixotropic agents, viscosity modifiers, defoamers, dehydrating agents, plasticizers, weather-resistant agents, antioxidants, heat stabilizers, lubricants, antistatic agents, whitening agents, colorants, conductive agents, mold release agents, surface treatment agents, flame retardants, and various fillers. These additives may be included in the mixture or added during the wet mixing process.

[0173] In this method, at least an organic resin is included as a mixing component, and the mass ratio of the organic resin to the F polymer in the wet mixing is 0.1 or more, and the total content of the organic resin and the F polymer in the resulting viscoelastic material is 40% by mass or more.

[0174] When the proportion of this organic resin is within this range, the F particles are unlikely to re-agglomerate, making it easy to obtain this viscoelastic material with excellent uniformity and dispersibility. Furthermore, when the total mass content of the F polymer and organic resin is within this range, the viscosity during wet mixing tends to increase, and the F particles are thoroughly mixed with the organic resin, easily yielding this viscoelastic material with excellent uniformity and dispersibility.

[0175] Furthermore, in this method, it is preferable to dry-crush the powder of the F polymer into F particles, and then wet-mix the particles with the thermosetting resin varnish at a mass ratio of the thermosetting resin to the F polymer of 0.1 or more.

[0176] When using a varnish made of thermosetting resin as the organic resin, the thermosetting resin and F particles readily interact with each other through the solvent. During wet mixing, the thermosetting resin partially cures and thickens due to the heat generated during mixing, while simultaneously mixing with the F particles. Furthermore, when the mass ratio of the thermosetting resin to the F polymer is within the specified range, this viscoelastic contains a sufficient amount of thermosetting resin relative to the F particles. As a result, it is believed that the surface of the F particles is easily and effectively covered and stabilized by the thermosetting resin, leading to improved uniformity and dispersibility of the viscoelastic.

[0177] The viscoelastic of the present invention comprises the F particles and the organic resin as the thermosetting resin, wherein the mass ratio of the thermosetting resin to the mass of the F polymer is 0.1 or more, and the total content of the mass of the F polymer and the mass of the thermosetting resin is 40% by mass or more.

[0178] This viscoelastic contains a certain amount of F particles and thermosetting resin in a high proportion, has high viscosity, and because the thermosetting resin easily covers the surface of the F particles, the F particles are difficult to aggregate, and the uniformity and dispersibility tend to be good.

[0179] The definitions and scope of the F polymer, F particles, organic resin, and other components that may be included in the viscoelastic are the same as those in this method.

[0180] The mass ratio of the thermosetting resin to the F polymer is preferably 0.2 or more. This ratio is preferably 20 or less, more preferably 10 or less, and even more preferably 1 or less.

[0181] The total content of polymer F and thermosetting resin is preferably 60% by mass or more. The total content is 100% by mass or less, preferably 80% by mass or less.

[0182] The viscoelastic material can be suitably manufactured by the method described herein.

[0183] By further diluting the viscoelastic material with water or a non-aqueous solvent, a dispersion with a viscosity of 10,000 mPa·s or less can be obtained. This viscoelastic material exhibits excellent uniformity and dispersibility; therefore, by diluting it, a dispersion with excellent liquid properties such as dispersion stability, uniformity, rheology, coatability, and storage stability (hereinafter also referred to as "this dispersion") can be obtained. Furthermore, since the viscosity of the obtained dispersion is within the aforementioned range, its dispersion stability is particularly excellent, and a thick layer can be formed when using the obtained dispersion to form a layer containing polymer F.

[0184] As a non-aqueous solvent, examples can be given of the same non-aqueous solvents used in the wet mixing process, and the preferred non-aqueous solvents are also the same.

[0185] Furthermore, this viscoelastic material can be mixed with organic resins or inorganic particles to form this dispersion. Due to the excellent uniformity and dispersibility of this viscoelastic material, even if it is further mixed with organic resins or inorganic particles, the F particles are difficult to agglomerate again, and a dispersion with excellent liquid properties such as dispersion stability, uniformity, rheology, coatability, and storage stability can be obtained.

[0186] Examples of organic resins and inorganic particles may be the same as those described herein, and preferably the same as those described. The organic resins and inorganic particles mixed with this viscoelastic may also be the same as or different from those contained in this viscoelastic.

[0187] The content of F particles in the resulting dispersion is preferably 10% by mass or more, more preferably 20% by mass or more. The content of F particles is preferably 60% by mass or less, more preferably 50% by mass or less.

[0188] When diluting this viscoelastic material with water or non-aqueous solvents, or when mixing it with organic resins or inorganic particles, the same mixer as described above can be used for dilution or mixing. The mixer used is preferably a rotary mixer or a thin-film gyratory high-speed mixer.

[0189] The viscosity of this dispersion is preferably 10 mPa·s or higher, more preferably 100 mPa·s or higher. The viscosity of this dispersion is preferably 5000 mPa·s or lower, more preferably 3000 mPa·s or lower.

[0190] The thixotropic ratio of this dispersion is preferably 1.0 to 3.0.

[0191] When the dispersion contains water, the pH value of the dispersion is preferably 5 to 10, and more preferably 8 to 10.

[0192] To adjust the pH value of this dispersion, a pH adjuster or pH buffer can be added during the preparation of this viscoelastic or dispersion. Examples of pH adjusters include amines, ammonia, and citric acid. Examples of pH buffers include tris(hydroxymethyl)aminomethane, ethylenediaminetetraacetic acid, ammonium bicarbonate, ammonium carbonate, and ammonium acetate.

[0193] When manufacturing this dispersion from this viscoelastic material, the surfactant, the curing agent, or the additive may be further added.

[0194] The viscoelastic and dispersion obtained by the above method can be used as coating materials to impart insulation, heat resistance, corrosion resistance, chemical resistance, water resistance, impact resistance, and thermal conductivity.

[0195] This viscoelastic and its dispersion can be specifically used in printed circuit boards, thermal interface materials, power module substrates, motors and other power equipment, coils, vehicle engines, heat exchangers, tubes, syringes, ampoules, medical wires, secondary batteries such as lithium-ion batteries, primary batteries such as lithium batteries, free radical batteries, solar cells, fuel cells, lithium-ion capacitors, hybrid capacitors, capacitors, aluminum electrolytic capacitors or tantalum electrolytic capacitors and other capacitors, electrochromic devices, electrochemical switching devices, electrode adhesives, electrode diaphragms, and electrodes such as positive or negative electrodes.

[0196] Furthermore, this viscoelastic and its dispersion can also be used as adhesives for bonding components. Specifically, this viscoelastic and its dispersion can be used for bonding ceramic components, bonding metal components, bonding IC chips or electronic components such as resistors and capacitors on substrates of semiconductor elements and module components, bonding circuit boards and heat sinks, and bonding LED chips to substrates.

[0197] Furthermore, this viscoelastic and dispersion containing conductive fillers can also be used in applications requiring conductivity, such as printed electronics. Specifically, it can be used to manufacture conductive components in printed circuit boards, sensor electrodes, etc.

[0198] This viscoelastic and this dispersion are suitable for use as negative resist compositions.

[0199] The resist composition can be applied to the surface of a substrate using methods such as screen printing, bar coating, or blade coating. After coating, the film is dried, and the resulting dried film is exposed using an exposure mask with a predetermined exposure pattern. The exposed dried film is then developed with a developer and cured by irradiation with ultraviolet light to obtain a laminate containing a substrate and a cured film on the substrate surface.

[0200] In addition, this viscoelastic and this dispersion are also suitable as filler materials for filling through holes or recesses in multilayer printed circuit boards.

[0201] The filling of the vias or recesses by the viscoelastic material and dispersion can be achieved by screen printing, roller coating, die coating, or vacuum printing. In this case, it is preferable to fill the composition to the extent that it protrudes from the vias or recesses.

[0202] This viscoelastic or dispersion can be suitably used to manufacture laminates having a substrate layer and an F-containing polymer layer (hereinafter also referred to as "F layer") on the surface of the substrate layer.

[0203] One method for manufacturing a laminate is as follows: the dispersion is coated onto the surface of a substrate, the solvent is removed by heating as needed, and the polymer F is further heated to form the F layer. Alternatively, if the organic resin in the dispersion is a thermosetting or photocurable resin, the dispersion can be coated onto the surface of a substrate, the solvent is removed by heating as needed, and then the organic resin is cured by heating or light irradiation to form the F layer.

[0204] Examples of substrates include: metal substrates such as metal foils made of copper, nickel, aluminum, titanium and alloys of these metals; heat-resistant resin films such as polyimide, polyamide, polyetheramide, polyphenylene sulfide, polyallyl ether ketone, polyamide-imide, liquid crystal polyester, and tetrafluoroethylene polymers; prepreg substrates, which are precursors to fiber-reinforced resin substrates; ceramic substrates such as silicon carbide, aluminum nitride, and silicon nitride; and glass substrates.

[0205] Examples of substrate shapes include planar, curved, and uneven surfaces. Furthermore, the substrate shape can be any of the following: foil, plate, film, or fibrous. The ten-point average roughness of the substrate surface is preferably 0.01–0.05 μm. The substrate surface can be surface-treated with a silane coupling agent or subjected to plasma treatment.

[0206] Examples of coating methods for the viscoelastic material and the dispersion include coating, droplet spraying, and immersion methods, with preferred methods being roller coating, blade coating, bar coating, mold coating, or spraying.

[0207] Heating to remove the solvent is preferably performed at 50–200°C for 0.1–30 minutes. Complete removal of the solvent is not required during this heating process; removal is sufficient to remove the solvent to the extent that the formed layer can maintain its self-supporting film properties. Furthermore, air can be blown during heating to facilitate the removal of the liquid dispersion medium through air drying.

[0208] The heating during the firing of polymer F is preferably carried out at a temperature above the firing temperature of polymer F, and more preferably at 360-400°C for 0.1-30 minutes.

[0209] Examples of heating devices used for various heating applications include ovens and ventilated drying furnaces. The heat source within the device can be a contact heat source such as hot air or a hot plate, or a non-contact heat source such as infrared radiation.

[0210] In addition, each heating can be carried out under normal pressure or under reduced pressure.

[0211] In addition, the atmosphere during each heating process can be any of the following: air atmosphere, helium, neon, argon, nitrogen, or other inert gas atmospheres.

[0212] When the viscoelastic or dispersion contains a thermosetting or photocurable resin as the organic resin, the organic resin can be cured by a method corresponding to the resin to form the F layer.

[0213] The F layer is formed by coating the viscoelastic material or dispersion with heat or light. These processes can be performed once or repeated two or more times. For example, the viscoelastic material or dispersion can be coated onto the surface of a substrate and heated to form the F layer, and then the viscoelastic material or dispersion can be coated onto the surface of the F layer and heated or irradiated with light to form a second F layer. Alternatively, the viscoelastic material or dispersion can be coated onto the surface of a substrate and heated to remove the solvent, and then the viscoelastic material or dispersion can be further coated onto the surface and heated or irradiated with light to form the F layer.

[0214] This viscoelastic and this dispersion can be coated on only one surface of the substrate, or on both sides of the substrate. In the former case, a laminate having a substrate layer and an F layer on one surface of the substrate layer is obtained; in the latter case, a laminate having a substrate layer and an F layer on both surfaces of the substrate layer is obtained.

[0215] Preferred examples of laminates include metal-clad laminates having a metal foil and an F layer on at least one surface of the metal foil, and multilayer films having a polyimide film and an F layer on both surfaces of the polyimide film.

[0216] The thickness of layer F is preferably 0.1–200 μm, more preferably 1–50 μm.

[0217] The peel strength between layer F and the substrate layer is preferably 10 to 100 N / cm.

[0218] Furthermore, a film containing the F polymer can be obtained by removing the substrate layer from the laminate.

[0219] The laminate having the F layer and the substrate can be used as antenna components, printed circuit boards, aircraft components, automotive components, sports equipment, food industry products, heat dissipation components, coatings, cosmetics, etc.

[0220] Specifically, it can be used as: wire coating material for aircraft wires, enameled wire coating material for motors in electric vehicles, electrical insulation tape, oil drilling insulation tape, oil delivery hoses, hydrogen tanks, materials for printed circuit boards, separation membranes such as precision filtration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, and gas separation membranes, electrode adhesives for lithium secondary batteries and fuel cells, copier rollers, covers for furniture, automotive dashboards, and household appliances, load bearings, yaw bearings, sliding shafts, valves, bearings, bushings, seals, thrust washers, mounting rings, pistons, slide switches, gears, cams, sliding parts for belt conveyors and food conveyors, tension ropes, wear-resistant pads, wear-resistant strips, tube lights, test sockets, wafer guides, wear parts for centrifugal pumps, pharmaceutical and water supply pumps, tools such as shovels, files, cutters, and saws, boilers, hoppers, pipes, ovens, baking molds, chutes, racket strings, molds, toilets, container coating materials, power devices, transistors, thyristors, rectifiers, transformers, and power MOSFETs. FETs, CPUs, heat sinks, metal heat sinks, blades of windmills or wind power generation equipment or aircraft, frames of personal computers or monitors, electronic device materials, automotive interior and exterior trim, sealing materials for processing machines or vacuum furnaces that perform heat treatment in low oxygen conditions, plasma processing devices, heat dissipation components in processing units such as sputtering or various dry etching devices, and electromagnetic wave shielding.

[0221] By impregnating the viscoelastic material and its dispersion in a fabric and then heating it, a fabric impregnated with polymer F can be obtained. The resulting fabric can also be described as a coated fabric covered with a layer of polymer F.

[0222] The preferred fabrics are glass fiber fabric, carbon fiber fabric, aramid fiber fabric, or metal fiber fabric.

[0223] Fabric can be surface-treated with silane coupling agents.

[0224] The content of F polymer in the resulting fabric is preferably 30-80% by mass.

[0225] When impregnating the viscoelastic material and the dispersion into a woven fabric, the fabric can be immersed in the viscoelastic material and the dispersion, or the viscoelastic material and the dispersion can be coated onto the fabric.

[0226] As a method for drying the fabric coated with the viscoelastic material and the dispersion, an example can be given that is the same heating method used to obtain the laminate.

[0227] Alternatively, the obtained woven fabric and the substrate can be arranged facing each other and then hot-pressed together to form a laminate in which the substrate and the woven fabric are stacked in sequence.

[0228] The resulting woven fabric can be used for the same purposes as the laminated body. In addition, this fabric can also be used as a lining material for the inner wall surfaces of components such as tanks, pipes, and containers.

[0229] The present invention, the viscoelastic material, and the method for obtaining a dispersion of the viscoelastic material obtained by the present invention and the viscoelastic material obtained by the present invention have been described above, but the present invention is not limited to the configuration of the above embodiments.

[0230] For example, in the above-described embodiments, any other steps may be added to the method and the method for obtaining the dispersion from the viscoelastic material obtained by the method, or they may be replaced with any other steps that perform the same function. Furthermore, in the above-described embodiments, any other configuration may be added to the viscoelastic material and the viscoelastic material of the present invention, or they may be replaced with any other configuration that performs the same function.

[0231] Example

[0232] The present invention will be described in detail below through embodiments, but the present invention is not limited to these embodiments.

[0233] 1. Preparation of each ingredient

[0234] [Powder]

[0235] Powder 1: Composed of 97.9 mol% TFE units, 0.1 mol% NAH units, and 2.0 mol% PPVE units, per 1×10 6 Powder composed of particles (D50: 2.1 μm) of a thermomeltable polymer (glass transition temperature: 80 °C, hereinafter also referred to as "F polymer 1") with 1000 carbon atoms in the main chain and containing carbonyl groups.

[0236] Powder 2: Composed of 98.7 mol% TFE units and 1.3 mol% PPVE units per 1×10 6 Powder composed of particles (D50: 1.8μm) of a polymer with 40 carbon atoms in its main chain containing carbonyl groups (glass transition temperature: 80℃, hereinafter also referred to as "F polymer 2").

[0237] [Mixed Ingredients]

[0238] Mixed Component 1: A liquid composition of resin varnish containing a phenolic resin with a carboxyl group (acid value: 80 mg KOH / g, a light-curing and thermosetting resin, hereinafter also referred to as "aromatic resin 1") and toluene as a solvent.

[0239] Mixed component 2: A slurry-like liquid composition containing silica particles (D50: 1.0 μm) and toluene as a solvent.

[0240] 2. Preparation of viscoelastic materials and dispersions

[0241] [Example 1]

[0242] Powder 1 was placed in a rotary mixer and then the mixer was run at 2000 rpm and 50°C for 5 minutes for dry pulverization. Next, the mixture 1 was added to the rotary mixer and the mixer was run at 2000 rpm and 100°C for 5 minutes for wet mixing to obtain a viscoelastic 1 containing 60 parts by mass of F polymer 1 particles and 40 parts by mass of aromatic resin 1 (viscosity measured by capillary rheology: 5000 Pa·s, compressive modulus: 0.6 MPa).

[0243] The resin varnish of viscoelastic 1 and aromatic resin 1 was put into a rotary mixer and then the mixer was run at 2000 rpm for 5 minutes to obtain a dispersion 1 containing 20 parts by mass of powder 1 and 80 parts by mass of aromatic resin 1 (viscosity: 300 mPa·s).

[0244] [Example 2]

[0245] Except for changing powder 1 to powder 2, the same procedure was followed as in Example 1 to obtain viscoelastic body 2 (viscosity measured by capillary rheology: 7000 Pa·s, compressive modulus: 0.7 MPa) and dispersion 2 (viscosity: 500 mPa·s).

[0246] [Example 3]

[0247] Except for dry pulverization at 90°C, viscoelastic body 3 (viscosity measured by capillary rheology: 9000 Pa·s, compressive modulus: 0.9 MPa) and dispersion 3 (viscosity: 800 mPa·s) were obtained by the same operation as in Example 1.

[0248] [Example 4]

[0249] Except for wet mixing at 70°C, viscoelastic body 4 (viscosity measured by capillary rheology: 10000 Pa·s, compressive modulus: 0.9 MPa) and dispersion 4 (viscosity: 800 mPa·s) were obtained by the same procedure as in Example 1.

[0250] [Example 5]

[0251] Powder 2 and mixture 1 were added to a rotary mixer, and the mixer was run at 2000 rpm for 5 minutes to mix, resulting in a viscoelastic body 5 containing 60 parts by mass of powder 2 and 40 parts by mass of aromatic resin 1. The viscoelastic body 5 had low homogeneity, therefore, viscosity and compressive modulus measurements by capillary rheology could not be performed. Viscoelastic body 5 and aromatic resin 1 were added to a rotary mixer, and the mixer was run at 2000 rpm for 5 minutes to obtain a dispersion 5 containing 20 parts by mass of powder 2 and 80 parts by mass of aromatic resin 1 (viscosity: 1200 mPa·s).

[0252] 3. Evaluation

[0253] 3-1. Homogeneity of viscoelasticity

[0254] Visually confirm the homogeneity of each viscoelastic body and evaluate it according to the following criteria.

[0255] [Evaluation Criteria]

[0256] ○: It is in a uniform state and will not crack even when pressed.

[0257] △: It is in a uniform state, but cracks appear when pressed.

[0258] ×: Bubbles are visible on the surface and will burst when pressed.

[0259] 3-2. Dispersibility of Dispersions

[0260] Visually confirm the dispersion state of each dispersion and evaluate it according to the following criteria.

[0261] ○: No clumps were produced even after being placed at 25°C for 7 days.

[0262] △: Aggregates are produced when placed at 25°C for 7 days, but they can be easily redispersed.

[0263] ×: Aggregates formed after being placed at 25℃ for 7 days and are difficult to redisperse.

[0264] 3-3. Smoothness of the convex surface

[0265] In a laminate of polymer 1 film and electrolytic copper foil (manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., "CF-T49A-DS-HD2"), each dispersion is coated on the surface of the electrolytic copper foil opposite to the polymer 1 film, forming a coating film on the laminate. The coating film is dried at 80°C for 10 minutes to obtain a dried film with a thickness of 50 μm.

[0266] Next, the dried film was irradiated with ultraviolet light using an exposure mask with openings of a specified pattern. The cumulative ultraviolet irradiation dose was 150 mJ / cm².2 .

[0267] Next, the dried film after ultraviolet irradiation was developed with a 1.0% by mass sodium carbonate aqueous solution.

[0268] Next, heat at 150°C for 50 minutes to cure the developed and dried film to form protrusions.

[0269] The formed convexity was confirmed using an optical microscope and evaluated according to the following criteria.

[0270] [Evaluation Criteria]

[0271] ○: No gaps are generated on the convex surface.

[0272] △: A gap is created on a part of the convex surface.

[0273] ×: Creates a void across the entire surface of the protrusion.

[0274] 3-4. Adhesion of the polymer layer

[0275] Each dispersion was coated onto an electrolytic copper foil (manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., "CF-T49A-DS-HD2") to form a coating film. The coating film was dried at 80°C for 10 minutes to obtain a dried film (thickness: 50 μm).

[0276] Next, without using an exposure mask, the entire dried film was irradiated with ultraviolet light, and then further heated at 150°C for 50 minutes to cure it and form a polymer layer, thus obtaining a copper-clad laminate with a polymer layer on the surface of the electrolytic copper foil. The cumulative ultraviolet irradiation intensity was 150 mJ / cm². 2 .

[0277] A rectangular test piece measuring 100 mm in length and 10 mm in width was cut from the obtained copper-clad laminate. The polymer layer and copper foil were then peeled off to a position 50 mm from one end of the test piece along its length. The maximum load at a 90-degree peel angle was then measured using a tensile testing machine (Orientec) at a tensile speed of 50 mm / min, with the position 50 mm from one end of the test piece as the center. This maximum load was taken as the peel strength and evaluated according to the following criteria.

[0278] [Evaluation Criteria]

[0279] 〇: Peel strength is above 10 N / cm

[0280] △: Peel strength is 5 N / cm or higher and less than 10 N / cm

[0281] ×: Peel strength less than 5 N / cm

[0282] 3-5. Electrical properties of the polymer layer

[0283] The electrolytic copper foils of each copper-clad laminate obtained by the same operation as in 3-4 were etched with an aqueous solution of ferric chloride to obtain individual polymer layers. Samples measuring 10 cm in length and 5 cm in width were cut from the obtained individual polymer layers, and the dielectric loss tangent was measured using the SPDR (Separated Column Dielectric Resonant Cavity) method (measurement frequency: 10 GHz), and evaluated according to the following criteria.

[0284] [Evaluation Criteria]

[0285] 〇: Dielectric constant below 3.5

[0286] △: Dielectric constant greater than 3.5 and less than 4.0

[0287] ×: Dielectric constant exceeds 4.0

[0288] These evaluation results are summarized in Table 1 below.

[0289] [Table 1]

[0290] Viscoelastic or dispersion number 1 2 3 4 5 homogeneity of viscoelastic materials ○ ○ △ △ × Dispersibility of dispersion ○ △ △ △ × Smoothness of convex surface ○ △ △ △ × Adhesion of polymer layer ○ △ △ △ × Electrical properties of polymer layers ○ ○ △ △ ×

[0291] 4. Preparation of Viscoelastic Bodies and Dispersions (Part Two)

[0292] [Example 6]

[0293] Powder 1 was added to a rotary mixer and then the mixer was run at 2000 rpm and 50°C for 5 minutes for dry pulverization. Next, mixture 2 was added to the rotary mixer and the mixer was run at 2000 rpm and 100°C for 5 minutes for wet mixing. Mixture 1 was then added again and the mixer was run under the same conditions for 5 minutes for wet mixing, resulting in a viscoelastic body 6 containing 34 parts by mass of F polymer 1 particles, 33 parts by mass of silica particles, and 33 parts by mass of aromatic resin 1. The viscoelastic body 6 was mixed with toluene to obtain a dispersion 6 containing 15% by mass of F polymer 1 particles.

[0294] [Example 7]

[0295] First, mix 1 is added to a self-rotating and revolutionizing mixer, then mix 2 is added to it. Otherwise, the same procedure as in Example 6 is followed to obtain viscoelastic body 7 and dispersion 7.

[0296] Both dispersions 6 and 7 have low viscosity, which suppresses foaming and provides excellent workability. However, comparing dispersions 6 and 7 reveals that dispersion 6 has an even lower viscosity, further suppressing foaming. Furthermore, dispersion 6 also offers better workability.

[0297] Industrial availability

[0298] The results above show that the viscoelastic material obtained by this method can produce a dispersion with excellent dispersion stability and other liquid properties. The dispersion obtained from this viscoelastic material has excellent dispersibility, and the polymer layer of the resulting laminate has excellent smoothness, adhesion, and electrical properties.

Claims

1. A method for manufacturing a viscoelastic material, wherein, The powder of a thermoplastic tetrafluoroethylene-based polymer is dry-pulverized to obtain particles of the tetrafluoroethylene-based polymer. The particles are then wet-mixed with a thermosetting resin in the presence of a liquid substance to obtain a viscoelastic material comprising the particles and the thermosetting resin. The dry pulverization is carried out at a temperature below the glass transition temperature of the tetrafluoroethylene polymer, and the wet mixing is carried out at a temperature above the glass transition temperature of the tetrafluoroethylene polymer.

2. The manufacturing method as described in claim 1, wherein, The dry pulverization is carried out using at least one type of mixer selected from Henschel mixer, pressure kneader, Banbury mixer, planetary mixer, ball mill, pulverizer, basket mill, sand mill, sand mill, stirred mill, microemulsifier, nano-processor, dissolver, and disperser.

3. The manufacturing method as described in claim 1, wherein, The wet mixing is carried out using at least one mixer selected from Henschel mixer, pressure kneader, Banbury mixer, planetary mixer, ball mill, pulverizer, basket mill, sand mill, sand grinder, stirred mill, microemulsion disperser, nano-processing machine, ultrasonic homogenizer, dissolver, disperser, and thin film gyratory high-speed mixer.

4. The manufacturing method as described in claim 1, wherein, The glass transition temperature of the tetrafluoroethylene-based polymer is 60–150 °C.

5. The manufacturing method as described in claim 1, wherein, The thermosetting resin is at least one aromatic resin selected from aromatic epoxy resin, phenolic resin, aromatic polyimide resin, aromatic polyimide resin precursor, aromatic polyamide-imide resin, and aromatic polyamide-imide resin precursor.

6. The manufacturing method as described in claim 1, wherein, The wet mixing is carried out by wet mixing the particles with a liquid composition containing a thermosetting resin.

7. The manufacturing method as described in claim 6, wherein, The liquid composition contains at least a thermosetting resin, the mass ratio of the thermosetting resin to the tetrafluoroethylene polymer in the wet mixing is 0.1 or more, and the total content of the tetrafluoroethylene polymer and the thermosetting resin in the viscoelastic body is 40% by mass or more.

8. A method for manufacturing a viscoelastic material, wherein, The powder of a thermosetting tetrafluoroethylene-based polymer is dry-pulverized to obtain particles of the tetrafluoroethylene-based polymer. Then, the particles are wet-mixed with a varnish of the thermosetting resin at a mass ratio of 0.1 or higher between the mass of the thermosetting resin and the mass of the tetrafluoroethylene-based polymer to obtain a viscoelastic material containing the particles and the thermosetting resin. The dry pulverization is carried out at a temperature below the glass transition temperature of the tetrafluoroethylene polymer, and the wet mixing is carried out at a temperature above the glass transition temperature of the tetrafluoroethylene polymer.

9. A method for preparing a dispersion, wherein, The viscoelastic material obtained by the manufacturing method according to any one of claims 1 to 8 is further diluted with water or a non-aqueous solvent to obtain a dispersion with a viscosity of less than 10,000 mPa·s.

10. A method for preparing a dispersion, wherein, The viscoelastic material obtained by the manufacturing method according to any one of claims 1 to 8 is further mixed with an organic resin or inorganic particles to obtain a dispersion.