Method for manufacturing composite member and composite member

Abstract

To provide a new method for producing a composite member having high flexural strength and flexural modulus, and to provide a new composite member used as a reinforced composite member having high flexural strength and flexural modulus or as an intermediate material for producing such a reinforced composite member.SOLUTION: A method for manufacturing a composite member includes preparing a suspension of an aggregate by co-aggregating flake-like particles and thermosetting or thermoplastic particles in a liquid to form the aggregate, making a papermaking product by papermaking the suspension, and hot press molding the papermaking product.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a composite member and a composite member. [Background technology]

[0002] Composite materials in which a filler such as inorganic particles is added to a matrix material such as a resin to improve strength and elastic modulus are widely used as various structural materials. For example, Patent Document 1 describes a method of producing a composite member by papermaking a mixture containing thermoplastic particles and flaky inorganic particles, and then hot-pressing and molding the paper. Patent Document 2 describes a method of producing a laminated mica product with improved flexural modulus and flexural strength by crushing uncalcined mica to obtain mica flakes, papermaking a slurry containing the mica flakes, and impregnating or coating the resulting laminated mica material with a thermosetting resin composition, followed by molding under heat and pressure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-002885 [Patent Document 2] Japanese Patent Application Publication No. 57-82598 Summary of the Invention [Problem to be solved by the invention]

[0004] When a composite member in which flake particles are added as a filler to a matrix material such as a resin is produced by papermaking as described in Patent Document 1, differences in the specific gravity and shape of the matrix material particles and the flake particles cause the flake particles to deposit first on the surface of the papermaking mesh (wire mesh, filter, etc.) and cover the mesh surface due to differences in sedimentation rate, slowing the rate at which the dispersion medium such as water passes through the mesh and is discharged, lengthening the papermaking time, during which time the distribution of the matrix material particles and flake particles in the papermaking solution becomes uneven, resulting in uneven distribution of the matrix material particles and flake particles across the thickness of the resulting paper. It is difficult to produce a composite member with sufficient strength and elastic modulus from a papermaking product in which the matrix material particles and flake particles are not uniformly mixed.

[0005] Thus, the present disclosure provides novel methods for producing composite members having high flexural strength and flexural modulus, as well as novel composite members for use as reinforced composite members having high strength and modulus or as intermediate materials for producing such reinforced composite members. [Means for solving the problem]

[0006] Aspects of the present disclosure include the following. [Aspect 1] preparing a suspension of said agglomerates by co-agglomerating flake particles and thermoset or thermoplastic particles in a liquid to form said agglomerates; preparing a paper product by filtering the suspension; hot-press molding the paper product; A method for manufacturing a composite member, comprising: [Aspect 2] 2. The method of embodiment 1, wherein the agglomerates are formed by adding an aggregating agent to a dispersion comprising the flaked particles and the thermoset or thermoplastic particles. [Aspect 3] 3. The method of embodiment 2, wherein the dispersion further comprises a surfactant. [Aspect 4] Aspect 4. The method of any one of Aspects 1 to 3, wherein the flaky particles are mica particles. [Aspect 5] Aspect 5. The method of any one of Aspects 1 to 4, wherein the thermosetting or thermoplastic particles are silicone resin particles, phenolic resin particles, polyamide resin particles, epoxy resin particles, or glass particles. [Aspect 6] a matrix of a cured silicone resin or a cured phenolic resin; Flake particles dispersed in the matrix; A composite member comprising: A composite member with a porosity of 0% to 10%. [Aspect 7] 7. The composite member according to embodiment 6, wherein the porosity is 0% to 6%. [Aspect 8] The following formula: E c = αV fx E x +V fy E y (In the formula, E c is the flexural modulus of the composite material (GPa), α is the reinforcing efficiency of the flake particles, V fx is the volume fraction of flake particles relative to the volume of the composite, E x is the elastic modulus of the flake particles (GPa), V fy is the volume fraction of the matrix relative to the volume of the composite member, E y represents the elastic modulus of the matrix (GPa). A composite member according to aspect 6 or 7, wherein a reinforcing efficiency α of the flaky particles defined by the formula (2) is 0.39 or more. [Effects of the Invention]

[0007] The composite member obtained by the manufacturing method of the present disclosure has high flexural strength and flexural modulus, and can be used as a reinforced composite member having high flexural strength and flexural modulus, or as an intermediate material for manufacturing such a reinforced composite member. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a flowchart showing a method for manufacturing a composite member according to an embodiment. [Figure 2] FIG. 2 is a diagram schematically showing a cross section of a composite member according to an embodiment. [Figure 3] FIG. 3 is a cross-sectional image of the molded article of Example 2 taken by a scanning electron microscope (SEM). [Figure 4] FIG. 4 is a cross-sectional SEM image of the molded body of Example 3. [Figure 5] FIG. 5 is a cross-sectional SEM image of the molded body of Example 4. [Figure 6] FIG. 6 is a cross-sectional SEM image of the molded body of Example 6. [Figure 7] FIG. 7 is a cross-sectional SEM image of the molded body of Example 7. DETAILED DESCRIPTION OF THE INVENTION

[0009] In this application, unless otherwise specified, numerical ranges expressed using the symbol "~" include the numerical values ​​written before and after the symbol "~" as the lower and upper limits, respectively. The upper and lower limits described in this application can be used alone or in any combination.

[0010] In this application, unless otherwise specified, "comprising" means that additional components or elements may be included, and includes "consisting essentially of" and "consisting of." "Consisting essentially of" means that additional components or elements may be included that do not have a substantial adverse effect. "Consisting of" means that the material or element is included only, but does not exclude the further inclusion of unavoidable impurities.

[0011] <Method of manufacturing composite materials> As shown in FIG. 1, the method for manufacturing a composite member according to the embodiment includes the steps of: preparing a suspension of aggregates (S1); papermaking the suspension to produce a paper product (S2); and hot-pressing the paper product (S3).

[0012] (1) Preparation of aggregate suspension (S1) The agglomerate suspension is prepared by co-agglomerating the flake particles and the thermoset or thermoplastic particles in a liquid to form agglomerates (co-agglomerates).

[0013] Examples of flake particles that can be used include particles of inorganic materials such as mica (e.g., natural mica, synthetic mica, gold mica, white mica), smectite, talc, carbonates, silicates, phosphates, and metals. In the present application, the term "flake-like" refers to a particle in which the equivalent circle diameter of the surface (flat surface) with the largest projected area is greater than the maximum length (thickness) in the direction perpendicular to the surface, and can also be referred to as scale-like, plate-like, or thin-plate-like. The flake particles may have an average diameter d of, for example, 100 nm to 5,000 μm and an average thickness t of, for example, 10 nm to 10 μm. The aspect ratio of the flake particles, i.e., the ratio d / t of the average diameter to the average thickness, may be, for example, 100 or more, and particularly 100 to 10,000. The average diameter d of the flake particles is determined by the median diameter d measured using a laser diffraction particle size analyzer. 50 The average thickness t of the flaky particles can be determined by measuring the thickness of 30 or more particles from a cross-sectional image of the flaky particles obtained using an SEM and calculating the arithmetic mean of the obtained values.

[0014] Thermosetting particles may contain an uncured thermosetting material as a major component or may consist essentially of an uncured thermosetting material. Examples of thermosetting materials include thermosetting resins such as silicone resins, phenolic resins, epoxy resins, unsaturated polyester resins, vinyl ester resins, epoxy acrylate resins, urethane acrylate resins, phenoxy resins, alkyd resins, urethane resins, maleimide resins, and cyanate resins, as well as crosslinkable rubbers such as natural rubber, polybutadiene rubber, styrene-butadiene rubber, hydrogenated styrene-butadiene rubber, acrylonitrile-butadiene rubber, butyl rubber, chlorinated butyl rubber, chloroprene rubber, acrylic rubber, urethane rubber, isoprene rubber, ethylene-propylene rubber, fluorine-containing rubber, and silicone rubber. Thermosetting materials may be used singly or in combination. In addition to the uncured thermosetting material, the thermosetting particles may further contain additives such as a curing catalyst, a polymerization initiator (such as a thermal polymerization initiator or a photopolymerization initiator), a curing accelerator, an antifoaming agent, a flame retardant, a colorant, a pigment, a phosphor, a mold release agent, an antioxidant, and an ultraviolet absorber. In this application, the phrase "contains as a main component" means that the specified component accounts for more than 50% of the total weight. The component specified as the main component may account for 70% or more, 80% or more, 90% or more, 95% or more, or 99% or more of the total weight.

[0015] Thermoplastic particles contain a thermoplastic material as a major component or consist essentially of a thermoplastic material. Examples of thermoplastic materials include thermoplastic resins such as polypropylene (PP) resin, polyamide (PA) resin, polycarbonate (PC) resin, polyurethane resin, fluororesin, polyphenylene sulfide (PPS) resin, and polyethersulfone (PES) resin, as well as glass and cellulose. In this application, the term "thermoplastic material" also encompasses compositions containing monomers, oligomers, or prepolymers that polymerize upon heating to form a thermoplastic resin. An example of such a composition is a composition containing a monomer, oligomer, or prepolymer that polymerizes to form a thermoplastic epoxy resin. One type of thermoplastic material may be used alone, or two or more types may be used in combination. In addition to the above-mentioned thermoplastic material, the thermoplastic particles may further contain additives such as antifoaming agents, flame retardants, colorants, pigments, phosphors, mold release agents, antioxidants, and UV absorbers.

[0016] Since the thermosetting or thermoplastic particles form the matrix phase in the composite member produced by the method according to the embodiment, the thermosetting or thermoplastic particles will hereinafter be referred to as "matrix material particles" as appropriate.

[0017] The matrix material particles may be solid or liquid, or in a glassy or rubbery state. When the matrix material particles are solid or glassy, ​​they may have any shape, such as spherical, flake-like, rod-like, or fibrous. When the matrix material particles are spherical, they may have an average particle diameter of 10 nm to 30 μm. The average particle diameter of the matrix material particles is measured using dynamic light scattering (DLS). When the average particle diameter of the matrix material particles exceeds 10 μm, the median diameter is measured using a laser diffraction particle size analyzer. When the matrix material particles are fibrous, they may have a length of 1 mm or less. The length of the matrix material particles can be measured using an electron microscope image or an optical microscope image. When the matrix material particles have a shape other than spherical or fibrous, their average major axis diameter may be 10 nm to 30 μm. The major axis diameter refers to the maximum distance between two parallel lines tangent to a two-dimensional projection image of the particle. The average major axis diameter can be determined by measuring the major axis diameters of 30 or more particles from a two-dimensional projection image of the particles obtained using an SEM and calculating the arithmetic mean of the obtained values. When the matrix material particles are in a liquid or rubbery state, the matrix material particles may have an average particle diameter of 10 nm to 30 μm. The average particle diameter of the matrix material particles in a liquid or rubbery state is determined by the median diameter measured using dynamic light scattering (DLS). When the average particle diameter of the matrix material particles exceeds 10 μm, the median diameter measured using a laser diffraction particle size distribution analyzer is used.

[0018] As the liquid that is the dispersion medium for the aggregates, for example, a polar solvent such as water or alcohol can be used, and in particular, water can be used.

[0019] An example of the operation of co-agglomerating flake particles and matrix material particles in a liquid will now be described.

[0020] First, a dispersion of matrix material particles is prepared. When the matrix material particles are in a liquid or rubbery state, the dispersion is also called an emulsion. When the matrix material particles are in a rubbery state, the dispersion is also called a latex. The dispersion of matrix material particles may further contain a surfactant, if necessary. Flake particles are added to the prepared dispersion of matrix material particles and stirred. A dispersion containing matrix material particles and flake particles is thus obtained. The flake particles may be added by directly adding the flake particles to the dispersion of matrix material particles, or by combining the dispersion of matrix material particles with the dispersion of flake particles. The dispersion of flake particles may also further contain a surfactant, if necessary. When at least one of the dispersion of matrix material particles or the dispersion of flake particles contains a surfactant, the dispersion containing matrix material particles and flake particles to be prepared contains a surfactant. Next, a flocculant is added to the obtained dispersion containing matrix material particles and flake particles. This causes the matrix material particles to adhere to the flake particles and co-agglomerate, resulting in a suspension of agglomerates.

[0021] The surfactant can be selected from anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. These surfactants can be used alone or in combination. For example, when mica particles having a negative surface charge in water are used as flake particles, applying an anionic surfactant to the matrix material particles to make the surface charge of the matrix material particles negative can improve the dispersion stability of the matrix material particles and the flake particles due to electrostatic repulsion.

[0022] Examples of anionic surfactants include carboxylate surfactants, sulfate surfactants, sulfonate surfactants, and phosphate surfactants.

[0023] Examples of carboxylate surfactants include alkyl (C8-C20) carboxylates such as sodium octanoate, sodium decanoate, sodium laurate, sodium myristate, and sodium stearate; halogenated alkyl (C8-C20) carboxylates such as sodium perfluorooctanoate and sodium perfluorononanoate; sodium N-lauroyl sarcosinate, sodium cocoyl glutamate, α-sulfofatty acid methyl ester salts, sodium cholate, sodium deoxycholate, and sodium glycocholate.

[0024] Examples of sulfate ester salt surfactants include alkyl (C8-C20) sulfate ester salts such as sodium dodecyl sulfate, ammonium dodecyl sulfate, and sodium myristyl sulfate; alkyl (C8-C20) ether sulfate ester salts such as sodium laureth sulfate; and polyoxyethylene alkyl (C8-C20) aryl sulfonates such as sodium polyoxyethylene alkyl (C8-C20) phenolsulfonate.

[0025] Examples of sulfonate surfactants include alkyl (C8-C20) sulfonates such as sodium octanesulfonate, sodium decane sulfonate, and sodium lauryl sulfonate; linear alkyl (C8-C20) aryl sulfonates such as sodium octylbenzenesulfonate and linear alkyl (C8-C20) benzenesulfonate (LAS); alkylaryl sulfonates such as sodium toluenesulfonate, sodium cumenesulfonate, and sodium butylnaphthalenesulfonate; halogenated alkyl sulfonates such as perfluorooctanesulfonate; and α-olefin (C8-C20) sulfonates such as sodium 1-tetradecenesulfonate and sodium hexadecenesulfonate.

[0026] Examples of phosphate ester salt surfactants include alkyl (C8-C20) phosphate ester salts such as sodium lauryl phosphate.

[0027] Examples of cationic surfactants include quaternary ammonium salt surfactants, amine salt surfactants, and pyridinium salt surfactants.

[0028] Examples of quaternary ammonium salt surfactants include tetraalkylammonium salts such as octyltrimethylammonium chloride, dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, cetyltrimethylammonium bromide, dimethyldioctadecylammonium chloride, didecyldimethylammonium chloride, and distearyldimethylammonium chloride; trialkylmonoarylammonium salts such as benzyltrimethylammonium chloride, benzyltriethylammonium chloride, triethylbenzylammonium chloride, benzyldimethyltetradecylammonium chloride, benzalkonium chloride, and benzalkonium bromide; dialkyldiarylammonium salts; and tetraarylammonium salts.

[0029] Examples of amine salt surfactants include monoalkylamine hydrochlorides such as dodecylamine hydrochloride; dialkylamine hydrochlorides such as didodecylamine hydrochloride; and trialkylamine hydrochlorides such as tridodecylamine hydrochloride.

[0030] Examples of pyridinium salt surfactants include alkyl (C8-C20) pyridinium salts such as dodecylpyridinium chloride and cetylpyridinium chloride.

[0031] Examples of nonionic surfactants include alkyl glucoside type surfactants, ether type surfactants, ester type surfactants, ester ether type surfactants, alkanolamide type surfactants, and alcohol type surfactants.

[0032] Examples of alkyl glucoside surfactants include n-octyl-β-D-glucoside, n-decyl-β-D-glucoside (decyl glucoside), n-octyl-β-D-maltoside, n-dodecyl-β-D-glucoside (lauryl glucoside), n-heptyl-β-D-thioglucoside, n-octyl-β-D-thioglucoside, and n-nonyl-β-D-thiomaltoside.

[0033] Examples of ether surfactants include polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ethers and polyoxypropylene alkyl ethers; polyoxyalkylene alkylaryl ethers such as polyoxyethylene nonylphenyl ether and polyoxyethylene octylphenyl ether; polyoxyalkylene aryl ethers such as polyoxyethylene aryl ether and polyoxypropylene aryl ether; polyoxyalkylene alkylene alkyl ethers such as polyoxyethylene alkylene alkyl ethers; polyoxyalkylene polyoxyalkylene glycols such as polyoxyethylene polyoxypropylene glycol; (poly)alkylene glycol alkyl ethers such as (poly)ethylene glycol monoethyl ether; (poly)alkylene glycol aryl ethers such as (poly)ethylene glycol monophenyl ether; alkyl carbitols; alkylamine ethers such as alkylamine EO adducts, alkyldiamine EO adducts, and alkylamine EOPO adducts; and polyhydroxyalkyl ethers.

[0034] Examples of ester surfactants include fatty sorbitan esters, fatty acid sucrose esters, and fatty acid polyglycerin esters.

[0035] Examples of ester ether surfactants include polyoxyethylene glycerin fatty acid esters, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene hexitane fatty acid esters, and sorbitan fatty acid ester polyethylene glycol.

[0036] Examples of alkanolamide surfactants include aliphatic alkanolamides such as lauric acid diethanolamide, oleic acid diethanolamide, stearic acid diethanolamide, and cocamide diethanolamine.

[0037] Examples of alcohol surfactants include alkyl (C8-C20) alcohols such as cetyl alcohol; fatty alcohols such as stearyl alcohol and oleyl alcohol; and alkyl alkanolamines such as N-methyldiethanolamine.

[0038] Examples of amphoteric surfactants include alkyl betaine surfactants, fatty acid amidopropyl betaine surfactants, alkyl imidazole surfactants, amino acid surfactants, and amine oxide surfactants.

[0039] The flocculant may be a polymer, an organic acid, an organic acid salt, a polyvalent metal compound, or a metal complex. These flocculants may be used alone or in combination of two or more. The flocculant to be used may be appropriately selected depending on the surface charge of the matrix material particles and the flake particles in the dispersion containing the matrix material particles and the flake particles.

[0040] Examples of polymers used as flocculants include cationic polymer flocculants such as polyacrylamide, polyacrylic acid ester, polymethacrylic acid ester, polyamine, and polydicyandiamide; anionic polymer flocculants such as polyacrylamide and sodium polyacrylate; nonionic polymer flocculants such as polyacrylamide and polyethylene oxide; and amphoteric polymer flocculants such as dimethylaminoethyl acrylate.

[0041] Examples of organic acids used as flocculants include organic compounds having an acidic group such as a phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a sulfuric acid group, a sulfonic acid group, a sulfinic acid group, or a carboxy group. Examples of organic compounds having a carboxy group include (meth)acrylic acid, poly(meth)acrylic acid, acetic acid, formic acid, benzoic acid, glycolic acid, malonic acid, malic acid (preferably DL-malic acid), maleic acid, succinic acid, glutaric acid, pimelic acid, adipic acid, fumaric acid, citric acid, tartaric acid, phthalic acid, 4-methylphthalic acid, lactic acid, pyrrolidonecarboxylic acid, pyronecarboxylic acid, pyrrolecarboxylic acid, furancarboxylic acid, pyridinecarboxylic acid, coumaric acid, thiophenecarboxylic acid, and nicotinic acid.

[0042] Examples of organic acid salts used as the flocculant include salts of the organic acids exemplified above, such as sodium salts, potassium salts, magnesium salts, or calcium salts.

[0043] Examples of polyvalent metal compounds used as flocculants include salts of at least one metal selected from the group consisting of magnesium, calcium, aluminum, and zinc and at least one acid selected from the group consisting of the organic acids exemplified above, nitric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, and thiocyanic acid.

[0044] Examples of metal complexes used as flocculants include metal complexes containing at least one metal selected from the group consisting of zirconium, aluminum, and titanium, and at least one ligand selected from the group consisting of acetate, acetylacetonate, methylacetoacetate, ethylacetoacetate, octylene glycolate, butoxyacetylacetonate, lactate, lactate ammonium salt, and triethanolamine.

[0045] In the suspension of the aggregate, the volume fraction V of the flake particles relative to the total volume of the flake particles and matrix material particles fxmay be 5% to 80% by volume, 40% to 70% by volume, or 40% to 60% by volume, thereby enabling the composite member produced by the method according to the embodiment to have higher strength and elastic modulus.

[0046] In addition to the flake particles, matrix material particles, dispersion medium, surfactant, and flocculating agent described above, the aggregate suspension may optionally contain further components, such as additives such as antioxidants, ultraviolet absorbers, mold release agents, plasticizers, flame retardants, pigments, and defoamers.

[0047] (2) Preparation of paper products (S2) The prepared suspension is then papered to produce a paper product. Papermaking can be carried out in accordance with JIS P 8222:2015. Specifically, when the suspension is papered using a machine similar to that used in the papermaking industry, aggregates are deposited on the mesh to form a wet mat. The liquid (dispersion medium) contained in the wet mat is removed by drying or other methods to obtain a sheet- or plate-shaped paper product.

[0048] In the method according to the embodiment, the matrix material particles and the flake particles are deposited on the mesh as co-agglomerates, resulting in a uniform mixture of the matrix material particles and the flake particles, resulting in a paper product in which the matrix material particles are sandwiched between the flake particles. In the method according to the embodiment, because the matrix material particles form co-agglomerates with the flake particles, even if the matrix material particles are smaller than the pore size of the mesh, the matrix material particles can be deposited on the mesh together with the flake particles. Therefore, a mesh with a large pore size can be used regardless of the size of the matrix material particles, thereby improving papermaking throughput.

[0049] In the paper product, the flake particles are arranged overlapping each other and oriented so that the thickness direction of the flake particles is parallel to the thickness direction of the paper product. A particulate or liquid matrix material is present between the overlapping flake particles. In this application, "parallel" includes not only exact parallelism but also substantial parallelism. Specifically, the average angle between the two directions may be 30 degrees or less, preferably 20 degrees or less, more preferably 10 degrees or less, and particularly preferably 5 degrees or less.

[0050] (3) Hot press molding (S3) A composite member is produced by hot-press molding a paper product. Depending on the shape of the composite member to be produced, multiple sheets of paper product may be stacked and hot-press molded. Furthermore, to improve handleability, the stacked paper products may be preliminarily pressed together before hot-press molding. When the matrix material particles used are thermosetting particles, hot-press molding is performed as follows. First, the paper product is heated to a temperature at which the thermosetting particles can flow, and pressure is applied. This causes the thermosetting particles to flow, filling the spaces between the flaky particles with the thermosetting material. Next, the paper product is heated to a temperature above the hardening temperature and below the decomposition temperature of the thermosetting particles to harden the thermosetting material. This results in the paper product being molded to obtain a composite member. When the matrix material particles used are thermoplastic particles, hot-press molding is performed by heating the paper product to a temperature above the melting temperature and below the decomposition temperature of the thermoplastic particles. This causes the thermoplastic particles to melt, filling the spaces between the flaky particles with the thermoplastic material. The thermoplastic material is then cooled to solidify. As a result, the paper product is molded into a composite member.

[0051] As a result, a composite member is obtained that includes a matrix containing a cured product of a thermosetting material derived from thermosetting particles or a thermoplastic material derived from thermoplastic particles, and flaky particles dispersed in the matrix. The flaky particles are highly oriented so that the thickness direction of the flaky particles is parallel to the thickness direction of the composite member. The matrix preferably consists essentially of a cured product of a thermosetting material derived from thermosetting particles or a thermoplastic material derived from thermoplastic particles, and particularly consists of a cured product of a thermosetting material derived from thermosetting particles or a thermoplastic material derived from thermoplastic particles.

[0052] The composite material to be produced preferably contains no or only a small amount of filler having a shape other than flake-like, such as fibrous. Examples of fibrous fillers include metal fibers, wood fibers, natural fibers, recycled fibers, semi-synthetic fibers, synthetic fibers, carbon fibers, glass fibers, and ceramic fibers. By containing no or only a small amount of filler having a shape other than flake-like, the flake particles can be highly oriented in the above-mentioned papermaking process, allowing the composite material to have high bending strength and bending modulus. The content of filler having a shape other than flake-like is preferably such that the filler does not adversely affect the orientation of the flake-like particles. For example, the content of filler having a shape other than flake-like, based on the total mass of the composite material, may be less than 15% by mass, preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0% by mass.

[0053] In the manufacturing method according to the embodiment, a composite member in which flake particles are highly oriented can be produced by using a papermaking process. Furthermore, since the paper product is produced using a suspension of aggregates formed by co-aggregating matrix material particles and flake particles in a liquid, the matrix material particles and flake particles are uniformly mixed in the paper product, with the matrix material particles sandwiched between the flake particles. Furthermore, even if the matrix material particles are smaller than the mesh size of the papermaking device, the matrix material particles can be deposited on the mesh together with the flake particles while suppressing or preventing the matrix material particles from passing through the mesh. When matrix material particles with smaller particle sizes are used, a paper product in which the matrix material particles and flake particles are more uniformly mixed can be produced. By hot-pressing the paper product produced in this manner, a composite member in which the flake particles serving as a filler are uniformly dispersed in the matrix can be produced. This structure of the composite member allows the composite member to have a high elastic modulus and high strength. Furthermore, in the manufacturing method according to the embodiment, the matrix material particles are suppressed or prevented from passing through the mesh, making it easy to control the volume fraction of the matrix and flake particles in the manufactured composite member.

[0054] <Composite materials> 2, a composite material 10 according to the embodiment includes a matrix 2 and flake particles 4 dispersed in the matrix 2. The composite material 10 can be manufactured by the method according to the embodiment described above.

[0055] The composite member 10 may have a plate-like shape. In this application, the term "plate-like" includes not only a flat plate-like shape as shown in Fig. 2, but also a curved plate-like shape having a curved portion.

[0056] The matrix 2 is formed from a cured silicone resin or a cured phenolic resin. The matrix 2 formed from a cured silicone resin or a cured phenolic resin can be formed by using uncured silicone resin particles or uncured phenolic resin particles as the matrix material particles in the method according to the above embodiment. The material and shape of the flake particles 4 are similar to those described in detail in the above embodiment, and therefore will not be described here.

[0057] The flake particles 4 are oriented so that their thickness direction is parallel to the thickness direction of the composite material 10. That is, the flake particles 4 are oriented so that the flat surfaces 4a of the flake particles 4 are parallel to the surface 10a of the composite material 10. This allows the composite material 10 to have sufficiently high bending strength and bending modulus. In this application, "parallel" includes not only exact parallelism but also substantial parallelism. Specifically, the average angle between two planes or directions may be 30 degrees or less, preferably 20 degrees or less, more preferably 10 degrees or less, and particularly preferably 5 degrees or less. The average angle between the flat surfaces 4a of the flake particles 4 and the surface 10a of the composite material 10 can be determined, for example, by determining the angles between the flat surfaces 4a of 30 or more flake particles 4 and the surface 10a of the composite material 10 from a cross-sectional SEM image or cross-sectional TEM image of the composite material 10 and averaging them.

[0058] The composite member 10 may contain the flaky particles 4 in an amount within a range of 5 volume % to 80 volume %, 40 volume % to 70 volume %, or 40 volume % to 60 volume %, based on the total volume of the composite member 10. When the composite member 10 contains the flaky particles 4 at such a volume fraction, the composite member 10 can have sufficiently high strength and elastic modulus.

[0059] In addition to the flaky particles 4 and the matrix 2, the composite material 10 may optionally contain additional components, such as additives such as antioxidants, UV absorbers, release agents, plasticizers, flame retardants, pigments, and defoamers. It is preferable that the composite material 10 contains no or only a small amount of fillers having a shape other than flakes, such as fibrous fillers. Examples of fibrous fillers include metal fibers, wood fibers, natural fibers, recycled fibers, semi-synthetic fibers, synthetic fibers, carbon fibers, glass fibers, and ceramic fibers. By containing no or only a small amount of fillers having a shape other than flakes, the flaky particles 4 can be highly oriented, allowing the composite material 10 to have high bending strength and bending modulus. The content of filler having a shape other than flake-like is preferably to the extent that the filler does not adversely affect the orientation of the flake-like particles 4; for example, the content of filler having a shape other than flake-like may be less than 15% by mass, preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0% by mass, based on the total mass of the composite material 10.

[0060] The composite member 10 has a porosity in the range of 0% to 10%. In particular, the composite member 10 may have a porosity in the range of 0% to 6%.

[0061] In the conventional technology described in Patent Document 2, when a composite material is produced by impregnating or coating a flake-shaped particle paper product with an uncured thermosetting resin and then molding it under heat and pressure, the uncured thermosetting resin must be sufficiently penetrated into the paper product to reduce the voids inside the composite material. However, uncured silicone resin and phenolic resin have high viscosity, making it difficult to fully penetrate the paper product. Therefore, the conventional technology described in Patent Document 2 makes it difficult to produce a composite material with a low porosity using a cured silicone resin or cured phenolic resin as a matrix, and it has not been possible to produce a composite material with a porosity of 10% or less. Specifically, when a composite material with a cured silicone resin or cured phenolic resin as a matrix is ​​produced using the method described in Patent Document 2, only composite materials with a porosity of 20% or more have been produced. However, in the method of the above embodiment, a suspension of aggregates formed by co-aggregating uncured silicone resin or phenolic resin particles and flake particles 4 in a liquid is used to produce a paper product, which is then hot-pressed to produce the composite member 10. This makes it possible to produce a composite member 10 with a low porosity of 10% or less, particularly 6% or less. Due to this low porosity, the composite member 10 can have a high elastic modulus and strength.

[0062] The porosity ε of the composite member 10 is calculated by the following formula: ε[%]=(1-ρ a / ρ t ) x 100 (In the formula, ρ a is the apparent density of the composite member 10, ρ t represents the theoretical density of the composite member 10.) It is calculated as follows.

[0063] Apparent density ρ of the composite member 10 a is determined by the underwater displacement method according to JIS K 7112-1:2023. When the composite member 10 has a simple shape such as a rectangular parallelepiped, the apparent density ρ is calculated by dividing the mass of the composite member 10 measured in air by the volume calculated from the outer dimensions of the composite member 10. a You may ask for:

[0064] Theoretical density ρ of the composite member 10 t is expressed by the following formula: ρ t =V fx ρ x +V fy ρ y (In the formula, V fx is the volume fraction of the flake particles 4 relative to the volume of the composite member 10, ρ x is the true density of the flake particles 4, V fy is the volume fraction of matrix 2 relative to the volume of composite member 10, ρ y represents the true density of matrix 2.) In this embodiment, the volume fraction V of the flaky particles 4 is calculated as follows: fx and the volume fraction of matrix 2, V fy The values ​​of the volume fraction of the flake particles 4 and the volume fraction of the matrix material particles used in the production of the composite member 10 are used as the volume fractions of the flake particles 4 and the matrix material particles, respectively. When the values ​​of the volume fraction of the flake particles 4 and the volume fraction of the matrix material particles used in the production of the composite member 10 are unknown, the volume fraction V of the flake particles 4 is used as the volume fraction V of the flake particles 4. fx and the volume fraction of matrix 2, V fy is the following formula:

number

[0065] Mass W of the flake particles 4 in the composite material 10 xcan be measured by decomposing and removing the matrix 2 of the composite member 10. For example, if the matrix 2 is a cured silicone resin, the matrix 2 can be decomposed with a mixed solution of methyl orthoformate, methanol, and sulfuric acid as described in Japanese Patent No. 3529854; if the matrix 2 is a cured resol-type phenolic resin, the matrix 2 can be decomposed with a supercritical aqueous solution of potassium hydroxide and ethanol; and if the matrix 2 is a cured novolac-type phenolic resin, the matrix 2 can be decomposed by heating in a solution containing an acid or alkali and excess phenol. The true density ρ of the flake-shaped particles 4 x is measured in accordance with JIS R 1622:1995. The true density ρ of the matrix y is measured in accordance with JIS K 7112-1:2023.

[0066] In the composite member 10, the following formula: E c = αV fx E x +V fy E y (In the formula, E c is the flexural modulus (GPa) of the composite member 10, α is the reinforcing efficiency of the flake particles, and V fx is the volume fraction of the flake particles 4 relative to the volume of the composite member 10, E x is the elastic modulus of the flake particle 4 alone (GPa), V fy is the volume fraction of matrix 2 relative to the volume of composite member 10, E y represents the elastic modulus (GPa) of matrix 2 alone.) The reinforcing efficiency α defined as follows can be 0.39 or more. Such a high reinforcing efficiency α is realized by the manufacturing method according to the above-described embodiment.

[0067] The flexural modulus of the composite material 10 is determined from a bending stress-bending strain curve obtained by a three-point bending test in accordance with JIS K 7017: 1999. Specifically, the flexural modulus is the gradient of the stress-strain curve within the elastic limit.

[0068] The composite member 10 can be used as a reinforced composite member having high flexural strength and flexural modulus. The composite member 10 may also be further molded for use. That is, the composite member 10 can be used as an intermediate material for producing a final product.

[0069] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design modifications can be made without departing from the technical scope described in the claims. [Example]

[0070] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0071] <Production of composite materials> Examples 1 and 2 (1) Preparation of suspension The thermosetting particles were prepared from silicone resin (KR-220LP manufactured by Shin-Etsu Chemical Co., Ltd.) particles (average particle diameter 10 μm) containing the curing catalyst zirconium tetraacetylacetonate (Orgatics ZC-162 manufactured by Matsumoto Fine Chemical Co., Ltd.). The weight ratio of the curing catalyst to the silicone resin in the thermosetting particles was 0.5:99.5. Gold mica particles (average diameter 250 μm, average thickness 1 μm) were used as flake particles.

[0072] The surfactant sodium deoxycholate (0.01 g) was added to a mortar, and one drop of water was added and mixed. The thermosetting particles were then added and mixed with a pestle. The process of adding water, adding thermosetting particles, and mixing was repeated until all of the thermosetting particles, by mass, listed in Table 1, were added to the mortar. The resulting mixture was added to water and stirred to disperse the thermosetting particles in 600 mL of water. The flaky particles, by mass, listed in Table 1, were then added and stirred to obtain a dispersion in which the flaky particles and thermosetting particles were dispersed in water.

[0073] 0.2 g of a cationic polymer flocculant (Himloc MP-684, manufactured by Hymo Corporation) was added to 200 mL of water and stirred for 2 hours. 10 g of the resulting solution was weighed out and diluted with 100 mL of water to prepare a flocculant solution. The flocculant solution was added to a dispersion of flake particles and thermosetting particles and stirred to co-aggregate the thermosetting particles and flake particles. This resulted in a suspension of aggregates of thermosetting particles and flake particles.

[0074] The volume fraction V of the flake particles relative to the total volume of the flake particles and thermosetting particles used is fx and the volume fraction of thermosetting particles V fy is calculated by taking the true density of the thermosetting particles (1.4 g / cm 3 ) and the true density of the flake particles (3.0 g / cm 3 ) and the results are shown in Table 1.

[0075] (2) Preparation of paper products The suspension was added to a papermaking apparatus equipped with a 70 mm diameter circular polytetrafluoroethylene (PTFE) membrane filter (average pore size: 6 μm), and then the suspension was filtered by suction from the bottom of the papermaking apparatus, causing aggregates to accumulate on the filter, forming a wet mat.

[0076] The wet mat was dried in a vacuum at 40°C for 12 hours. The wet mat was then pre-pressed at 100°C and then cooled in a cooling press. This resulted in a plate-shaped paper product. The thickness of the paper product after cooling pressing was 3.0 mm for Example 1 and 3.4 mm for Example 2.

[0077] (3) Hot and pressure molding A 50mm x 50mm square plate was cut from the cooled and pressed product and pressed using a hot press at 100°C and 1MPa for 20 minutes. Then, while maintaining the temperature at 100°C, the plate was pressed at 10MPa and then 5MPa. After that, the plate was pressed at 120°C and 5MPa for 5 minutes. Then, while maintaining the pressure at 5MPa, the plate was pressed at 140°C for 5 minutes, then 160°C for 5 minutes, then 180°C for 10 minutes. Finally, the plate was pressed at 5MPa while cooling. This resulted in a plate-shaped compact (composite member). The thickness of the compact was approximately 2mm.

[0078] When the obtained molded body was heated at 550°C, the cured silicone resin was converted into a ceramic, forming silica. Such molded bodies with a ceramic matrix can be used as heat-resistant materials.

[0079] Example 3 (1) Preparation of suspension Phenol resin particles (Bellpearl S899, average particle size 20 μm, manufactured by Air Water Inc.) were prepared as thermosetting particles. Gold mica particles similar to those in Example 1 were prepared as flake particles.

[0080] The surfactant sodium deoxycholate (0.05 g) was added to 700 mL of water and mixed. The thermosetting particles in the mass shown in Table 1 were added and mixed thereto. This resulted in the thermosetting particles being dispersed in 700 mL of water. Further, the flaky particles in the mass shown in Table 1 were added and stirred to obtain a dispersion in which the flaky particles and thermosetting particles were dispersed in water.

[0081] 0.2 g of a cationic polymer flocculant (Himoc MP-684, manufactured by Hymo Co., Ltd.) was added to 200 mL of water and stirred for 2 hours. 8 g of the resulting solution was weighed out and diluted with 100 mL of water to prepare a flocculant solution. The flocculant solution was added to the stirred dispersion of flaky particles and thermosetting particles, causing the thermosetting particles and flaky particles to co-aggregate. This resulted in a suspension of aggregates of thermosetting particles and flaky particles.

[0082] The volume fraction V of the flake particles relative to the total volume of the flake particles and thermosetting particles used is fx and the volume fraction of thermosetting particles V fy is calculated by taking the true density of the thermosetting particles (1.23 g / cm 3 ) and the true density of the flake particles (3.0 g / cm 3 ) and the results are shown in Table 1.

[0083] (2) Preparation of paper products The suspension was filtered using the same paper-making apparatus as in Example 1 to obtain a wet mat.

[0084] The wet mat was dried in a vacuum at 60°C for 12 hours, then pre-pressed at 100°C for 3 minutes and then cooled in a cooling press, thereby obtaining a sheet-shaped paper product.

[0085] (3) Hot and pressure molding A 50mm x 50mm square plate was cut from the cooled and pressed product. It was heated to 150°C for 3 minutes using a hot press, then pressed at 150°C and 10 MPa for 2 minutes, then at 170°C and 10 MPa for 5 minutes, then at 190°C and 10 MPa for 5 minutes, then at 210°C and 10 MPa for 5 minutes, and finally pressed at 5 MPa for 5 minutes while water-cooling. This resulted in a plate-shaped compact (composite member). The thickness of the compact was approximately 2mm.

[0086] Example 4 (1) Preparation of suspension Polyamide 12 resin particles (ORGASOL 2001 UD NAT1, manufactured by Arkema Inc., average particle diameter 5 μm) were prepared as thermoplastic particles. White mica particles (average diameter 280 μm, average thickness 1 μm) were prepared as flake particles.

[0087] The surfactant sodium deoxycholate (0.5 g) was added to a mortar, and one drop of water was added and mixed. Thermoplastic particles were then added and mixed with a pestle. The process of adding water, thermoplastic particles, and mixing was repeated until all of the thermoplastic particles, by mass, listed in Table 1, were added to the mortar. The resulting mixture was added to water and stirred to disperse the thermoplastic particles in 600 mL of water. Further, flake particles, by mass, listed in Table 1, were added and stirred to obtain a dispersion in which the flake particles and thermoplastic particles were dispersed in water.

[0088] 0.2 g of a cationic polymer flocculant (Himloc MP-684, manufactured by Hymo Co., Ltd.) was added to 200 mL of water and stirred for 2 hours. 40 g of the resulting solution was weighed out and diluted with 100 mL of water to prepare a flocculant solution. The flocculant solution was added to the stirred dispersion of flake particles and thermoplastic particles, causing the thermoplastic particles and flake particles to co-flocculate. This resulted in a suspension of aggregates of thermoplastic particles and flake particles.

[0089] The volume fraction V of the flake particles relative to the total volume of the flake particles and thermoplastic particles used is fx and the volume fraction of thermoplastic particles V fy is calculated by taking the true density of the thermoplastic particles (1.13 g / cm 3 ) and the true density of the flake particles (3.0 g / cm 3 ) and the results are shown in Table 1.

[0090] (2) Preparation of paper products The suspension was filtered using a paper-making apparatus in the same manner as in Example 1, except that a PTFE membrane filter with a diameter of 160 mm was used, to obtain a wet mat.

[0091] The wet mat was dried in a vacuum at 80°C for 12 hours, then pre-pressed at 180°C for 3 minutes and then cooled in a cooling press to obtain a sheet-shaped paper product.

[0092] (3) Hot and pressure molding Four 50mm x 50mm square sheets were cut from the cooled and pressed product and stacked. They were heated to 250°C for 5 minutes using a hot press, pressed at 250°C and 10 MPa for 5 minutes, and then pressed at 10 MPa for 5 minutes while water-cooling. A plate-shaped compact (composite member) was obtained. The thickness of the compact was approximately 2mm.

[0093] Example 5 (1) Preparation of suspension As the thermoplastic particles, borosilicate glass particles (4552, average particle diameter 2.9 μm, manufactured by Nippon Horoyaku Co., Ltd.) were prepared. As the flake particles, gold mica particles similar to those in Example 1 were prepared.

[0094] Thermoplastic particles of the mass shown in Table 1 were added to 300 mL of water and stirred ultrasonically for 5 minutes to disperse the thermoplastic particles in the water. Furthermore, flaky particles of the mass shown in Table 1 were added to 300 mL of water and stirred. This was combined with the dispersion of thermoplastic particles and stirred to obtain a dispersion in which the flaky particles and thermoplastic particles were dispersed in water.

[0095] 0.2 g of a cationic polymer flocculant (Himloc MP-684, manufactured by Hymo Co., Ltd.) was added to 200 mL of water and stirred for 2 hours. 15 g of the resulting solution was weighed out and diluted with 100 mL of water to prepare a flocculant solution. The flocculant solution was added to the stirred dispersion of flake particles and thermoplastic particles, causing the thermoplastic particles and flake particles to co-agglomerate. This resulted in a suspension of aggregates of thermoplastic particles and flake particles.

[0096] The volume fraction V of the flake particles relative to the total volume of the flake particles and thermoplastic particles used is fx and the volume fraction of thermoplastic particles V fy is calculated by taking the true density of the thermoplastic particles (3.02 g / cm 3 ) and the true density of the flake particles (3.0 g / cm 3 ) and the results are shown in Table 1.

[0097] (2) Preparation of paper products The suspension was filtered using a paper-making apparatus in the same manner as in Example 1 to obtain a wet mat.

[0098] The wet mat was dried in a vacuum at 120°C for 12 hours, then pre-pressed at 480°C for 3 minutes and then cooled to obtain a sheet-shaped paper product.

[0099] (3) Hot and pressure molding A 50mm x 50mm square plate was cut out from the cooled paper product and heated to 580°C for 10 minutes using a hot press. It was then pressed at 580°C and 10 MPa for 5 minutes and then allowed to cool naturally. This resulted in a plate-shaped molded product (composite member). The thickness of the molded product was approximately 2mm.

[0100] Example 6 A plate-shaped molded body (composite member) was produced in the same manner as in Example 5, except that borosilicate glass particles (4521 manufactured by Nippon Horoyaku Co., Ltd., average particle size 1.2 μm) were used as the thermoplastic particles, and the papermaking material was heated to 600°C for 10 minutes, pressed at 600°C and 10 MPa for 5 minutes, and then naturally cooled. The thickness of the molded body was approximately 2 mm.

[0101] Example 7 (1) Preparation of suspension A liquid epoxy resin was prepared. The epoxy resin was a mixture of bisphenol A diglycidyl ether (jER828 manufactured by Mitsubishi Chemical Corporation) as the base resin and diethylmethylbenzenediamine (jER Cure WA manufactured by Mitsubishi Chemical Corporation) as the curing agent in a weight ratio of 5.62:1.32.

[0102] 0.2 g of a surfactant (Alpha Resin W-12 manufactured by Alpha Kaken Co., Ltd.) was added to and mixed with the epoxy resin of the mass listed in Table 1. 43.75 mL of water was gradually added thereto while stirring and mixing, to obtain an emulsion in which liquid epoxy resin particles were dispersed in water. This emulsion was used as a dispersion of thermosetting particles.

[0103] The same white mica particles as in Example 4 were prepared as flake particles. The flake particles were added to 460 mL of water in the amount shown in Table 1 and stirred to prepare a suspension. The thermosetting particle dispersion (emulsion) and the flake particle suspension were combined and stirred. This produced a dispersion in which the flake particles and thermosetting particles were dispersed in stirred water.

[0104] 0.2 g of a cationic polymer flocculant (Himoc MP-684, manufactured by Hymo Corporation) was added to 200 mL of water and stirred for 2 hours. 19 g of the resulting solution was weighed out, and the flocculant solution was added to the stirred dispersion of flaky particles and thermosetting particles to co-aggregate the thermosetting particles and flaky particles. This resulted in a suspension of aggregates of thermosetting particles and flaky particles.

[0105] The volume fraction V of the flake particles relative to the total volume of the flake particles and thermosetting particles used is fx and the volume fraction of thermosetting particles V fy is calculated by taking the true density of the thermosetting particles (1.15 g / cm 3 ) and the true density of the flake particles (3.0 g / cm 3 ) and the results are shown in Table 1.

[0106] (2) Preparation of paper products The suspension was filtered using the same paper-making apparatus as in Example 4 to obtain a wet mat.

[0107] The wet mat was dried in a vacuum at 23° C. for 24 hours, thereby obtaining a sheet-shaped paper product.

[0108] (3) Hot and pressure molding A 50mm x 50mm square plate was cut from the dried paper product and heated to 100°C for 10 minutes using a heat press. It was then pressed at 200°C and 2MPa for 10 minutes, then at 250°C and 3.5MPa for 15 minutes, and finally at 3.5MPa for 5 minutes while cooling with water. This resulted in a plate-shaped compact (composite member). The thickness of the compact was approximately 1mm.

[0109] Comparative Examples 1 to 4 In Comparative Examples 1 to 4, dispersions of flake particles and thermosetting or thermoplastic particles in water were prepared in the same manner as in Examples 1, 3, 4, and 5, respectively. Paper products were produced in the same manner as in Examples 1, 3, 4, and 5, respectively, except that a dispersion of flake particles and thermosetting or thermoplastic particles without the addition of a flocculant solution was used instead of a suspension of aggregates of thermosetting or thermoplastic particles and flake particles. In all Comparative Examples, due to the shape of the flake particles and their greater specific gravity than the thermosetting or thermoplastic particles, the flake particles immediately settled during filtration in the papermaking machine and covered the surface of the filter. This slowed the drainage of water through the filter, prolonging the papermaking time and resulting in uneven distribution of the flake particles and thermosetting or thermoplastic particles in the suspension. As a result, uneven particle distribution was observed in the thickness direction of the resulting wet mat. That is, the lower part of the wet mat (the surface facing the filter and its vicinity) contained many flake particles, with almost no thermosetting or thermoplastic particles, while the upper part of the wet mat (the surface opposite the surface facing the filter and its vicinity) contained many thermosetting or thermoplastic particles, with almost no flake particles. The paper product obtained by drying, pre-pressing, and cooling the wet mat was so brittle that it was difficult to maintain its shape, and subsequent hot-press molding could not be performed. This is thought to be because the flake particles were not sufficiently bonded to each other due to the almost complete absence of thermosetting or thermoplastic particles in the lower part of the wet mat.

[0110] <Bending test> Four test pieces of 10 mm x 50 mm were cut out from the molded bodies of Examples 1 to 7, and the bending strength and bending modulus E cThe molded article of Example 1 was a silicone resin cured product that had not been converted into a ceramic. The measurement was carried out using an autograph AGS-10kNX manufactured by Shimadzu Corporation, in accordance with JIS K 7017:1999 (three-point bending test), with a support distance / test piece thickness of 16 and a test speed of 1 mm / min. The results are shown in Table 1. The values ​​shown in Table 1 are the average values ​​of the measurements for four test pieces. The molded articles of Examples 1 to 7 have high bending strength and bending modulus E c showed.

[0111] <Reinforcement efficiency> Flexural modulus E of molded bodies of Examples 1 to 4 and 7 c Based on the measurement results, the following formula: E c = αV fx E x +V fy E y (In the formula, E c is the bending modulus of the compact (GPa), α is the reinforcing efficiency of the flake particles (i.e., gold mica particles or white mica particles), and V fx is the volume fraction of flake particles relative to the volume of the compact, E x is the elastic modulus of the flake particles (GPa), V fy is the volume fraction of the matrix (i.e., the cured silicone resin, the cured phenolic resin, the cured polyamide resin, or the cured epoxy resin) relative to the volume of the molded body, E y represents the elastic modulus of the matrix (GPa). The reinforcing efficiency α of the flake particles was calculated, which is defined as follows. The elastic modulus E of the gold mica particles and the white mica particles was calculated as follows: x is set to 172 GPa, and the elastic modulus E of the cured silicone resin, cured phenolic resin, polyamide resin, and cured epoxy resin is y were respectively 0.75 GPa, 2.6 GPa, 2 GPa and 1.9 GPa. The determined values ​​of reinforcing efficiency α are shown in Table 1. The molded bodies of Examples 1 to 4 and 7 exhibited a high reinforcing efficiency α of 0.39 or more.

[0112] <Structural observation> The cross sections of the molded articles of Examples 2, 3, 4, 6, and 7 were observed with a scanning electron microscope (SEM). The obtained SEM images are shown in Figures 3 to 7, respectively. In the SEM images of Figures 3 to 5 and 7, the light-colored areas represent flake particles, and the dark-colored areas represent the cured silicone resin, cured phenolic resin, polyamide resin, or cured epoxy resin. In the SEM image of Figure 6, the light-colored areas represent glass, and the dark-colored areas represent flake particles. Figures 3 to 7 confirm that, in each molded article, flake particles highly oriented parallel to the surface of the molded article were well dispersed in the matrix of the cured silicone resin, cured phenolic resin, polyamide resin, glass, or cured epoxy resin. It is believed that the high bending strength and bending modulus were achieved due to the structure of such molded articles.

[0113] <Porosity> The length, width, thickness, and mass of the molded body of Examples 1 to 3 were measured. The volume of the molded body was calculated from the length, width, and thickness of the molded body, and the apparent density ρ of the molded body was calculated by dividing the mass of the molded body by the volume. a The volume fraction V of the flake particles in the compacts of each example was calculated. fx and the volume fraction of the cured thermosetting resin V fy , and the true density ρ of the flake particles x (Gold mica particles: 3.0 g / cm 3 ) and the true density ρ of the cured thermosetting resin y (True density of cured silicone resin: 1.4 g / cm 3 , True density of cured phenolic resin: 1.23 g / cm 3 ) from the theoretical density ρ of the compact of each example t The following formula: ρ t =V fx ρ x +V fy ρ y The porosity ε of the compact was calculated using the following formula: ε[%]=(1-ρ a / ρ t ) x 100 The results are shown in Table 1. The porosity ε was 6% or less in all of the molded articles of Examples 1 to 3. It is believed that such a low porosity contributes to the high bending strength and bending modulus of the molded articles.

[0114] [Table 1] [Explanation of symbols]

[0115] 2 matrix, 4 flake particles, 4a flat surface of flake particles, 10 composite member, 10a surface of composite member

Claims

1. preparing a suspension of said agglomerates by co-agglomerating flake particles and thermoset or thermoplastic particles in a liquid to form said agglomerates; preparing a paper product by filtering the suspension; hot-press molding the paper product; A method for manufacturing a composite member, comprising:

2. The method of claim 1 , wherein the agglomerates are formed by adding an aggregating agent to a dispersion containing the flaked particles and the thermoset or thermoplastic particles.

3. The method of claim 2 wherein the dispersion further comprises a surfactant.

4. The method according to any one of claims 1 to 3, wherein the flaky particles are mica particles.

5. The method according to any one of claims 1 to 3, wherein the thermosetting or thermoplastic particles are silicone resin particles, phenolic resin particles, polyamide resin particles, epoxy resin particles, or glass particles.

6. a matrix of a cured silicone resin or a cured phenolic resin; Flake particles dispersed in the matrix; A composite member comprising: A composite member having a porosity of 0% to 10%.

7. The composite member according to claim 6, wherein the porosity is 0% to 6%.

8. The following formula: E ｃ =αV ｆｘ E ｘ +V ｆｙ E ｙ (In the formula, E ｃ is the flexural modulus of the composite material (GPa), α is the reinforcing efficiency of the flake particles, V ｆｘ is the volume fraction of flake particles relative to the volume of the composite, E ｘ is the elastic modulus of the flake particles (GPa), V ｆｙ is the volume fraction of the matrix relative to the volume of the composite member, E ｙ represents the elastic modulus of the matrix (GPa). The composite member according to claim 6 or 7, wherein the reinforcing efficiency α of the flaky particles defined by the formula (2) is 0.39 or more.

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