Molded body

Abstract

To provide a shaped body having both flexibility and shape retainability.SOLUTION: A shaped product comprises an alumina-containing alumina fiber, an inorganic binder, and a surfactant, in which the content of the alumina is 70 mass% or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a molded article. [Background technology]

[0002] Typically, furnaces such as industrial furnaces are equipped with furnace materials (insulating materials) that have low heat capacity and thermal conductivity. Alkaline gases such as lithium gas and sodium gas may be generated from the material being fired inside the furnace, which can easily damage the furnace materials. Therefore, an inorganic molded body containing alumina, which can have excellent durability, has been proposed as a furnace material (see Patent Document 1).

[0003] Although the above-mentioned refractory materials have high strength and rigidity, they may be required to be flexible when installed in a furnace (for example, when fitting them to the curved shape of the furnace). On the other hand, the refractory materials are also required to have shape retention (specifically, shape retention after heating) so that they do not lose their shape due to vibrations during use of the furnace. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5203920 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve the above problems, and one of its objects is to provide a molded article that has both flexibility and shape retention. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a molded body, which includes aluminous fibers containing alumina, an inorganic binder, and a surfactant, and the alumina content is 70 mass % or more.

[0007] In one embodiment, the density of the compact is 80 kg / m 3 More than 200kg / m 3 The following is the result.

[0008] In one embodiment, the molded article has a recovery rate after 30% compression of 85% or more.

[0009] In one embodiment, the compact has a shrinkage rate at 1600°C of 3% or less.

[0010] In one embodiment, the molded body contains an organic binder.

[0011] In one embodiment, the content of the inorganic binder is 5% by mass or less.

[0012] In one embodiment, the content of the inorganic binder is 1% by mass or more.

[0013] In one embodiment, the surfactant comprises a cationic surfactant.

[0014] In one embodiment, the molded body is substantially free of refractory ceramic fibers.

[0015] In one embodiment, the molded body contains a polymer flocculant.

[0016] In one embodiment, the polymeric flocculant comprises a first polymeric flocculant and a second polymeric flocculant.

[0017] In one embodiment, the molded body contains alumina-based particles containing alumina, and contains the alumina-based fibers in an amount of 30 parts by mass or more and 70 parts by mass or less, the alumina-based particles in an amount of 30 parts by mass or more and 70 parts by mass or less, and the surfactant in an amount of 0.1 parts by mass or more and 10 parts by mass or less.

[0018] In one embodiment, the molded body is substantially free of alumina-based particles containing alumina, and contains the alumina-based fibers in an amount of 80 parts by mass or more and 120 parts by mass or less, the alumina-based particles in an amount of 5 parts by mass or less, and the surfactant in an amount of 0.1 parts by mass or more and 10 parts by mass or less. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a molded article that has both flexibility and shape retention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

[0021] A. Molded object The molded body in one embodiment of the present invention includes aluminous fibers, an inorganic binder, and a surfactant.

[0022] A-1. Alumina fiber The alumina fiber contains alumina (typically, α-alumina). The alumina content of the alumina fiber is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Such a content can provide, for example, excellent resistance to alkali and reducing atmospheres.

[0023] The aluminous fibers may contain components other than alumina, such as silica and zirconia.

[0024] The average length of the alumina fibers is preferably 100 μm to 100,000 μm, more preferably 1,000 μm to 80,000 μm, and particularly preferably 3,000 μm to 50,000 μm. The fiber diameter (diameter) of the alumina fibers is typically 3 μm to 12 μm, and preferably 3 μm to 10 μm. The aspect ratio (length / diameter) of the alumina fibers is typically 25 or more.

[0025] The crystallinity of the alumina may be selected depending on the properties required for the molded body, and two or more types of alumina fibers with different crystallinity of alumina may be used in combination. The crystallinity of the alumina contained in the alumina fiber may be, for example, less than 30%, preferably less than 20%. A crystallinity within this range may contribute to, for example, improving the flexibility of the resulting molded body. The crystallinity of the alumina contained in the alumina fiber may be, for example, 30% or more, preferably 40% or more. A crystallinity within this range may contribute to, for example, improving the heat shrinkage rate and alkali resistance of the resulting molded body.

[0026] A-2. Inorganic binder The inorganic binder may be formed of any suitable inorganic compound. Specific examples of the inorganic binder include silica, zirconia, titania, alumina, and bentonite. These may be used alone or in combination of two or more. Among these, silica is preferably used because it can provide the resulting molded body with superior shape retention (specifically, shape retention after heating).

[0027] The content of the inorganic binder in the molded body is, for example, 10% by mass or less, preferably 5% by mass or less, and more preferably 3.5% by mass or less. Such a content can result in the obtained molded body having even better flexibility. Meanwhile, the content of the inorganic binder in the molded body is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and more preferably 1% by mass or more. Such a content can result in the obtained molded body having even better shape retention (specifically, shape retention after heating).

[0028] A-3. Surfactants Any appropriate surfactant can be used as the surfactant. Examples of surfactants include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. These can be used alone or in combination of two or more. Among these, cationic surfactants and / or amphoteric surfactants are preferred, and cationic surfactants are more preferred. This is because the flexibility of the resulting molded body can be extremely excellent. Specifically, this is because the surfactant can be well fixed to alumina (especially aluminous fibers), which can be negatively charged in water, during the production of the molded body described below.

[0029] Specific examples of the cationic surfactant include quaternary ammonium salt, alkylamine salt, and pyridinium salt cationic surfactants. Examples of quaternary ammonium salt cationic surfactants include alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkylbenzalkonium salts, and N,N-dialkyloyloxyethyl-N-methyl,N-hydroxyethylammonium salts. Examples of alkylamine salt cationic surfactants include monoalkylamine salts, dialkylamine salts, and trialkylamine salts. Examples of pyridinium salt cationic surfactants include alkylpyridinium salts.

[0030] Examples of the cationic surfactant include amidoamine compounds such as stearic acid diethylaminoethylamide, stearic acid dimethylaminoethylamide, palmitic acid diethylaminoethylamide, palmitic acid dimethylaminoethylamide, myristic acid diethylaminoethylamide, myristic acid dimethylaminoethylamide, behenic acid diethylaminoethylamide, behenic acid dimethylaminoethylamide, stearic acid diethylaminopropylamide, stearic acid dimethylaminopropylamide, palmitic acid diethylaminopropylamide, palmitic acid dimethylaminopropylamide, myristic acid diethylaminopropylamide, myristic acid dimethylaminopropylamide, behenic acid diethylaminopropylamide, behenic acid dimethylaminopropylamide, etc. These may be used alone or in combination of two or more.

[0031] Specific examples of the amphoteric surfactant include betaine-type, imidazoline-type, amino acid-type, and amine oxide-type amphoteric surfactants. Examples of betaine-type amphoteric surfactants include alkyl betaine, fatty acid amidopropyl betaine, lauryl hydroxysulfobetaine, alkyl hydroxysulfobetaine, lecithin, and hydrogenated lecithin. Examples of imidazoline-type amphoteric surfactants include 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, 2-alkyl-1-(2-hydroxyethyl)imidazolinium betaine, and 2-alkyl-1-(2-hydroxyethyl)imidazolinium betaine. Examples of amphoteric surfactants of the amino acid type include alkyldiethylenetriaminoacetate, alkyloxyhydroxypropylarginine hydrochloride, sodium laurylaminodiacetate, dihydroxyalkylmethylglycine, sodium lauryldiaminoethylglycine, lauriminodipropionic acid, N-[3-alkyloxy-2-hydroxypropyl]-L-arginine hydrochloride, and sodium alkylaminodipropionate. Examples of amphoteric surfactants of the amine oxide type include alkyldimethylamine oxide. These may be used alone or in combination of two or more.

[0032] Examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol tetra fatty acid esters, glycerin fatty acid esters, sorbitan fatty acid esters, polyglycerin fatty acid esters, and sucrose fatty acid esters. These may be used alone or in combination of two or more.

[0033] The surfactant content in the molded product is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 0.8% by mass or more. Such a content can result in the molded product having even better flexibility. Meanwhile, the surfactant content in the molded product is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, and particularly preferably 1.5% by mass or less. This is because, for example, no significant difference in the flexibility of the molded product is observed.

[0034] A-4. Alumina particles In one embodiment, the molded body includes alumina particles containing alumina (typically, α-alumina). The alumina content of the alumina particles is, for example, 98% by mass or more, preferably 99.5% by mass or more.

[0035] The average particle size of the alumina particles is typically 1 μm to 100 μm. For example, from the viewpoint of shape retention after heating, the average particle size of the alumina particles is preferably 1 μm to 50 μm, and more preferably 1 μm to 10 μm. The average particle size can be measured using a laser diffraction particle size distribution analyzer.

[0036] By using alumina particles, the amount of alumina fibers used can be reduced, thereby reducing costs, for example. The content of alumina particles in the molded body is, for example, 70 mass % or less, preferably 50 mass % or less. With such a content, for example, the density described below can be satisfactorily satisfied and excellent flexibility can be achieved. In one embodiment, the density of the obtained molded body is adjusted by adjusting the content of alumina particles.

[0037] A-5. Organic binder Preferably, the molded article contains an organic binder. Examples of organic binders include acrylic, methacrylic, styrene, and butadiene resins, and starch. Among these, acrylic and methacrylic binders are preferred because the resulting molded article can have extremely excellent flexibility.

[0038] The content of the organic binder in the molded body is preferably 3% by mass or more and 12% by mass or less, more preferably 6% by mass or more and 10% by mass or less. Such a content can result in the obtained molded body having even better flexibility. In one embodiment, the molded body is substantially free of the starch. Specifically, the starch content of the molded body is, for example, 1% by mass or less, preferably 0.1% by mass or less, and more preferably 0.01% by mass or less.

[0039] A-6. Polymer flocculant Preferably, the molded body contains a polymer flocculant. By using the polymer flocculant, components contained in the slurry can be effectively aggregated to form flocs in the production of the molded body described below.

[0040] Any suitable polymer flocculant can be used as the polymer flocculant. Examples of polymer flocculants include cationic polymer flocculants, anionic polymer flocculants, amphoteric polymer flocculants, and nonionic polymer flocculants. These can be used alone or in combination of two or more. In one embodiment, a first polymer flocculant (e.g., an anionic polymer flocculant) is used. In another embodiment, a first polymer flocculant (e.g., an anionic polymer flocculant) and a second polymer flocculant (e.g., a cationic polymer flocculant) are used in combination.

[0041] Examples of the cationic polymer flocculants include acrylate-based polymer flocculants such as a polymer of quaternized dimethylaminoethyl acrylate and a copolymer of quaternized dimethylaminoethyl acrylate and acrylamide, methacrylate-based polymer flocculants such as a polymer of quaternized dimethylaminoethyl methacrylate and a copolymer of quaternized dimethylaminoethyl methacrylate and acrylamide, polyvinylamidines (amidine-based polymer flocculants) containing amide groups, nitrile groups, amine hydrochlorides, formamide groups, etc., and Mannich-modified polyacrylamides.

[0042] Examples of the anionic polymer flocculant include sodium polyacrylate, a copolymer of sodium acrylate and acrylamide, sodium polymethacrylate, and a copolymer of sodium methacrylate and acrylamide.

[0043] Examples of the amphoteric polymer flocculant include a copolymer of a quaternized product of dimethylaminomethyl acrylate, acrylamide, and acrylic acid, and a copolymer of a quaternized product of dimethylaminomethyl methacrylate, acrylamide, and acrylic acid.

[0044] Examples of the nonionic polymer flocculant include polyacrylamide and polyethylene oxide.

[0045] The content of the polymer flocculant in the compact is preferably 0.1% by mass or more, more preferably 0.15% by mass or more, while the content of the polymer flocculant in the compact is, for example, 5% by mass or less.

[0046] A-7. Inorganic flocculants The molded body may contain an inorganic flocculant. By using the inorganic flocculant, the components contained in the slurry can be effectively aggregated to form flocs in the production of the molded body described below. Specifically, the inorganic flocculant can contribute to improving the fixation of the inorganic binder to the alumina (especially the aluminous fibers).

[0047] Examples of the inorganic flocculant include aluminum salts such as aluminum sulfate and polyaluminum chloride (PAC), and ferric salts such as ferric chloride and polyferric sulfate. The content of the inorganic flocculant in the molded product is preferably 5% by mass or less. With this content, excellent flexibility can be maintained.

[0048] A-8.Content The alumina content in the above-mentioned molded body is, for example, 70% by mass or more, preferably 80% by mass or more, and particularly preferably 85% by mass or more. With such a content, the resulting molded body can have excellent alkali resistance. In one embodiment, the alumina content of the molded body is 92% by mass or less. In another embodiment, the alumina content of the molded body is 95% by mass or less.

[0049] As described above, in one embodiment, the molded body contains the alumina particles in addition to the alumina fibers. In this case, the molded body contains, for example, 30 to 70 parts by mass of the alumina fibers, 30 to 70 parts by mass of the alumina particles, and 0.1 to 10 parts by mass of the surfactant. The content of the alumina particles is preferably 40 to 230 parts by mass, more preferably 60 to 150 parts by mass, per 100 parts by mass of the alumina fibers. The content of the surfactant is preferably 0.1 to 10 parts by mass, per 100 parts by mass of the alumina fibers and the alumina particles combined.

[0050] In another embodiment, the molded body is substantially free of alumina particles. For example, the molded body contains 80 to 120 parts by mass of alumina fibers, 5 parts by mass or less of alumina particles, and 0.1 to 10 parts by mass of a surfactant. The content of the surfactant is preferably 0.1 to 10 parts by mass per 100 parts by mass of alumina fibers.

[0051] The molded body preferably does not substantially contain refractory ceramic fiber (RCF). Here, "substantially does not contain" means that the RCF content in the molded body is 1% by mass or less, preferably 0.5% by mass or less, more preferably 0.05% by mass or less, and particularly preferably 0.01% by mass or less. RCF typically contains alumina and silica. The alumina content in RCF is typically 30% by mass to 60% by mass, preferably 40% by mass to 60% by mass. The silica content in RCF is typically 40% by mass to 60% by mass. The fiber diameter of RCF is typically 1 μm to 3 μm. While a molded body containing such RCF can have both flexibility and shape retention, one of the features of the present invention is that a molded body that combines flexibility and shape retention can be realized without substantially containing RCF (for example, by using the above-mentioned thick alumina fibers that are easily embrittled by heating, while having the above-mentioned high alumina content).

[0052] B. Physical properties of the molded body The density of the compact is preferably 80 kg / m 3 More than 200kg / m 3 or less, more preferably 100 kg / m 3 More than 150kg / m 3 By having such a density, for example, excellent flexibility and shape retention can be achieved.

[0053] The 30% compression recovery rate of the molded article is, for example, 85% or more. In one embodiment, the 30% compression recovery rate of the molded article is preferably 92% or more. In another embodiment, the 30% compression recovery rate of the molded article is preferably 90% or more. One of the features of the present invention is that it can have such a high recovery rate. With such a compression recovery rate, it can have extremely excellent flexibility.

[0054] The heat shrinkage rate of the molded article (shrinkage rate at 1600°C) is preferably 3% or less, and may be 2% or less. With such a heat shrinkage rate, the molded article can be suitably used as, for example, a furnace material.

[0055] C. Manufacturing method of molded body The molded body is produced by any suitable method. In one embodiment, the method for producing the molded body includes adding the alumina fiber, the inorganic binder, and the surfactant to a dispersion medium to obtain a slurry, obtaining a wet molded body from the obtained slurry, and drying the obtained wet molded body.

[0056] C-1. Preparation of slurry Any appropriate dispersion medium can be used as the dispersion medium. Examples of the dispersion medium include water such as distilled water, ion-exchanged water, tap water, groundwater, and industrial water, and polar organic solvents. Examples of the polar organic solvent include monohydric alcohols such as ethanol and propanol, and dihydric alcohols such as ethylene glycol. Among these, water is preferred because it does not deteriorate the working environment and does not burden the environment.

[0057] When the inorganic binder is added to the dispersion medium, the inorganic binder may be in the form of a solid, a dispersion (suspension), or a solution. In the latter case, the inorganic binder is typically in the form of a colloidal sol (e.g., colloidal silica). Preferably, the inorganic binder is added to the dispersion medium in the form of a dispersion or a solution.

[0058] The alumina particles, polymer flocculant, inorganic flocculant, resin, or organic binder such as starch is added to the dispersion medium as needed. These may be in the form of a solid, a dispersion, or a solution when added to the dispersion medium. The flocculant is typically added in the form of a solution. The resin is typically added in the form of a dispersion (emulsion).

[0059] In one embodiment, the amount of colloidal sol added to the dispersion medium is preferably 0.5 to 3 parts by mass, more preferably 1 to 2 parts by mass, calculated as solid content, relative to 100 parts by mass of the alumina fibers and alumina particles combined. In another embodiment, the amount is preferably 2 to 6 parts by mass, more preferably 3 to 5 parts by mass, calculated as solid content, relative to 100 parts by mass of the alumina fibers.

[0060] The total solid concentration in the slurry (slurry concentration) is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.3% by mass or more and 8% by mass or less, and particularly preferably 0.5% by mass or more and 3% by mass or less.

[0061] The wet compact is typically obtained by dehydrating or molding the slurry.

[0062] The dehydration molding can be carried out by any suitable method. Specific examples include a suction dehydration molding method in which the slurry is poured into a mold with a mesh at the bottom and the dispersion medium is sucked out, and a pressure dehydration molding method. In this specification, the term "dehydration molding" also refers to a method in which a dispersion medium other than water is used.

[0063] The papermaking can be carried out by any suitable method, specific examples of which include a flow-on method in which a slurry is poured onto a strip-shaped porous carrier from a flow box, a Hatschek papermaking method, a Fourdrinier papermaking method, and other methods capable of continuously producing a paper from a slurry.

[0064] The wet compact preferably has a shape similar to the desired compact, such as a board, sheet, or block.

[0065] Any appropriate method can be used to dry the wet molded body. The drying temperature is, for example, 40°C to 180°C, preferably 60°C to 150°C, more preferably 80°C to 120°C, and particularly preferably 100°C to 120°C. The drying time is, for example, 6 hours to 48 hours, preferably 8 hours to 40 hours, more preferably 10 hours to 36 hours, and particularly preferably 12 hours to 20 hours. [Example]

[0066] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0067] [Example 1-1] One part by mass of cationic surfactant ("FS8006" texture improver manufactured by Seiko PMC) was added to water and stirred. 45 parts by mass of alumina fiber ("Denka Arsen B80" manufactured by Denka Corporation, alumina content 80% by mass, silica content 20% by mass), 55 parts by mass of alumina particles ("SA31" manufactured by Nippon Light Metal Co., Ltd., average particle size: 5 μm), 1.5 parts by mass of colloidal silica ("Silicadol 30" manufactured by Nippon Chemical Industry Co., Ltd., a suspension of 30% by mass of solids, average particle size of solids: 15 nm, pH: 10.0), and resin ("Arontack HV-C9081" manufactured by Toa Gosei Co., Ltd., 57-61% by mass of acrylic polymer, 39-43% by mass of water) were added. %, pH: 5.0 to 7.0, viscosity: 50 to 1,500 mPa s, Tg: -41°C) and 0.2 parts by mass of polyacrylic acid ("Polystron 705" manufactured by Arakawa Chemical Industries, Ltd., cationic, non-volatile content 10% by mass, pH: 2.5 to 3.5, viscosity: 300 to 1,000 cps), followed by the addition of 0.1 parts by mass of polyacrylamide ("30A113" manufactured by Asada Chemical Industries, Ltd., anionic, 0.1% by mass aqueous solution, pH: 6 to 8), and further adding water so that the resulting slurry concentration was 2% by mass, followed by stirring to obtain a slurry.

[0068] The slurry was dehydrated and molded to obtain a board-shaped wet molded body, which was then dried at 110° C. for 12 hours to obtain a molded body.

[0069] [Examples 1-2] to [Examples 1-4] Molded bodies according to Examples 1-2 to 1-4 were obtained in the same manner as in Example 1-1, except that an inorganic flocculant (liquid aluminum sulfate manufactured by Taimei Chemical Industry Co., Ltd., aluminum sulfate concentration 23.5 to 27.5 mass%) was added and the formulation was changed as shown in Table 1 below.

[0070] [Example 2-1] 1.1 parts by mass of cationic surfactant ("FS8006" texture improver manufactured by Seiko PMC) was added to water and stirred. 100 parts by mass of alumina fiber ("Denka Arsen B97N5" manufactured by Denka Corporation, alumina content 97% by mass, silica content 3% by mass), 4 parts by mass of colloidal silica ("Silicadol 30" manufactured by Nippon Chemical Industry Co., Ltd., suspension with 30% by mass of solid content, average particle size of solids: 15 nm, pH: 10.0) were added to the water and stirred. 3 parts by mass of inorganic flocculant (liquid aluminum sulfate manufactured by Taimei Chemical Industry Co., Ltd., aluminum sulfate concentration 23.5 to 27.5% by mass), resin ( 7.5 parts by mass of "Arontack HV-C9081" manufactured by Toagosei Co., Ltd. (acrylic polymer 57-61% by mass, water 39-43% by mass, pH: 5.0-7.0, viscosity: 50-1,500 mPa·s, Tg: -41°C) and 0.2 parts by mass of polyacrylamide ("30A113" manufactured by Asada Chemical Industry Co., Ltd., anionic, 0.1% by mass aqueous solution, pH: 6-8) were added, and water was added to give a slurry concentration of 2% by mass, followed by stirring to obtain a slurry.

[0071] The slurry was dehydrated and molded to obtain a board-shaped wet molded body, which was then dried at 110° C. for 12 hours to obtain a molded body.

[0072] [Example 2-2] to [Example 2-5] Molded articles according to Examples 2-2 to 2-5 were obtained in the same manner as in Example 2-1, except that the formulation was changed as shown in Table 1 below.

[0073] [Comparative Example 1] A molded body was obtained in the same manner as in Example 1-2, except that colloidal silica was not used.

[0074] Comparative Example 2 A molded body was obtained in the same manner as in Example 2-2, except that no surfactant was used.

[0075] Comparative Example 3 To water were added 60 parts by mass of alumina fiber (Denka Alcene B97N5 manufactured by Denka Corporation, alumina content 97% by mass, silica content 3% by mass), 40 parts by mass of alumina particles (Nippon Light Metal Co., Ltd., A11, average particle size: 50 μm), 8 parts by mass of colloidal silica (Nippon Chemical Industry Co., Ltd., Silicadol 30, suspension with a solid content of 30% by mass, average particle size of the solid content: 15 nm, pH: 10.0), 4 parts by mass of starch (Nippon Starch Chemical Co., Ltd., Petrosize J), and 3 parts by mass of polyacrylamide (Arakawa Chemical Industries Co., Ltd., Polystron 311, cationic, nonvolatile content: 10% by mass, pH: 4.2 to 4.8, viscosity: 500 to 1500 cps), and the mixture was stirred to obtain a slurry with a concentration of 2% by mass.

[0076] The resulting slurry was then poured into a mold with a mesh at the bottom, and dehydrated and molded by a suction dehydration molding method that sucks out water, to obtain a board-shaped wet molded body.

[0077] The resulting wet molded body was then dried at 110° C. for 36 hours to obtain a board-shaped molded body.

[0078] [Reference example] In water, 60 parts by mass of alumina fiber (Denka Alcene B80 manufactured by Denka, alumina content 80% by mass, silica content 20% by mass), 40 parts by mass of RCF (Nichias Fineflex 1300 Bulk, alumina content 50% by mass, silica content 50% by mass), resin (Toagosei Arontack HV-C9081, acrylic polymer 57 to 61% by mass, water 39 to 43% by mass, pH: 5.0 to 7.0, viscosity: 50 to 1,500 mPa) To the mixture were added 5.0 parts by mass of aluminum sulfate (liquid aluminum sulfate manufactured by Taimei Chemical Industry Co., Ltd., aluminum sulfate concentration 23.5 to 27.5% by mass), 1.3 parts by mass of an inorganic flocculant (liquid aluminum sulfate manufactured by Taimei Chemical Industry Co., Ltd., aluminum sulfate concentration 23.5 to 27.5% by mass), and 0.06 parts by mass of polyacrylic acid (Polystron 705 manufactured by Arakawa Chemical Industries Co., Ltd., cationic, non-volatile content 10% by mass, pH: 2.5 to 3.5, viscosity: 300 to 1000 cps), and then water was added so that the resulting slurry concentration was 2% by mass, and the mixture was stirred to obtain a slurry. The slurry was dehydrated and molded to obtain a board-shaped wet molded body, which was then dried at 110° C. for 12 hours to obtain a molded body.

[0079] <Evaluation method> The resulting molded articles were evaluated as follows. (1) Density The obtained molded body was processed into a plate as needed to prepare a measurement sample. The mass M (kg) of the measurement sample was measured using a balance. The volume V (m 3 ) was obtained using a vernier caliper, a steel tape measure, a steel straight ruler, or a non-contact measuring device (laser displacement meter, distance meter). From these values, the density M / V (kg / m 3 ) was calculated (rounded to the nearest integer). (2) 30% compression recovery rate Using a compression testing machine (Shimadzu Corporation's "Autograph AG-Xplus," load cell capacity: 50 kN, jig: φ100 mm fixed compression platen), the upper and lower compression platens were in contact with each other, and the displacement at which the stress reached 0.20 N was defined as the zero position. A test specimen measuring 50 mm thick, 50 mm wide, and 50 mm long was cut from the resulting compact. The test specimen was clamped between the upper and lower compression platens of the compression testing machine and set so that the compressive stress reached 0.20 N. The displacement at this point was defined as the test specimen thickness T1. The compression testing machine was then lowered at a rate of 5 mm / min, compressing the test specimen by 30% of its thickness, and then held at this 30% compression position for 5 minutes. After this hold, the compression testing machine was raised at a rate of 5 mm / min to release the compression of the test specimen. Upon release, the platens and the test specimen separated, and the test specimen was allowed to stand for 5 minutes from the time the compressive stress reached 0. After leaving it to stand, the compression testing machine was lowered again, and the displacement at which the compressive stress reached 0.20 N was taken as the test piece thickness T2. The compression recovery rate (%) was calculated using the formula: T2 / T1 × 100 (rounded to the nearest integer). (3) Heat shrinkage rate A test piece measuring 50 mm thick x 50 mm wide x 150 mm long was cut out from the obtained molded body, and the length L1 of the test piece was measured with a vernier caliper. The test piece was then subjected to a heating test in an electric furnace. Specifically, the temperature was increased at a rate of approximately 200°C / h, and the test piece was maintained at 1600°C for 3 hours. The electric furnace was then turned off and the test piece was allowed to cool naturally in the furnace. The length L2 of the test piece after the heating test was measured, and the heat shrinkage (%) was calculated using the formula: {(L1-L2) / L1} x 100 (the calculated value was rounded to one decimal place). (4) Shape retention after heating The obtained molded body was checked for its ability to be carried by hand (handling). In addition, the amount of alumina fibers and particles scattered during handling was evaluated by touch and visual inspection. The evaluation criteria were as follows: <Evaluation criteria> Good: Easy to handle, with little scattering of alumina fibers or particles. △: Handling is possible, but a lot of alumina fibers and particles fly off. ×: Handling is impossible. (5) Flexibility (touch) The molded articles were evaluated by touching them with the hand, and the evaluation criteria were as follows: <Evaluation criteria> 〇: Soft and resilient. △: Soft but not resilient. ×: Hard.

[0080] The evaluation results are summarized in Table 1.

[0081] [Table 1] [Industrial Applicability]

[0082] The molded article of the present invention can be used as a heat-resistant material or a heat insulating material for various applications. For example, it is preferably used as a furnace material. Specifically, it is preferably used as a furnace material for industrial furnaces such as baking furnaces for electronic components, crematoriums, physicochemical furnaces, etc.

Claims

1. 30 parts by mass or more and 70 parts by mass or less of aluminous fibers containing alumina; 30 parts by mass or more and 70 parts by mass or less of alumina particles containing alumina; 0.1% by mass or more and 10% by mass or less of colloidal silica as an inorganic binder; an acrylic polymer as an organic binder in an amount of 3% by mass or more and 12% by mass or less; 0.1% by mass or more and 10% by mass or less of a cationic surfactant which is a quaternary ammonium salt type, an alkylamine salt type, a pyridinium salt type, or an amidoamine compound; A molded body comprising: The content of the alumina in the molded body is 70% by mass or more, The density is 80 kg / m 3 or more and 200 kg / m 3 or less. Molded body.

2. The molded article according to claim 1, having a recovery rate after 30% compression of 85% or more.

3. The molded article according to claim 1 or 2, which has a shrinkage rate at 1600°C of 3% or less.

4. The molded article according to claim 1 , wherein the content of colloidal silica as the inorganic binder is 5% by mass or less.

5. The molded article according to claim 1 , wherein the content of colloidal silica as the inorganic binder is 1% by mass or more.

6. The molded article according to any one of claims 1 to 5, which is substantially free of refractory ceramic fibers.

7. A method for preparing a flocculant comprising: a cationic polymer flocculant, an anionic polymer flocculant, an amphoteric polymer flocculant, and a nonionic polymer flocculant, either singly or in combination of two or more of them; The cationic polymer flocculant is an acrylate-based polymer flocculant, a methacrylate-based polymer flocculant, an amidine-based polymer flocculant, or a Mannich-modified polyacrylamide; the anionic polymer flocculant is sodium polyacrylate, a copolymer of sodium acrylate and acrylamide, sodium polymethacrylate, or a copolymer of sodium methacrylate and acrylamide; the amphoteric polymer flocculant is a copolymer of a quaternized product of dimethylaminomethyl acrylate, acrylamide, and acrylic acid, or a copolymer of a quaternized product of dimethylaminomethyl methacrylate, acrylamide, and acrylic acid; The nonionic polymer flocculant is polyacrylamide or polyethylene oxide. The molded article according to any one of claims 1 to 6.

8. A molded body as described in claim 7, comprising two or more of the cationic polymer flocculant, the anionic polymer flocculant, the amphoteric polymer flocculant, and the nonionic polymer flocculant.

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