JP2022085606A - Mold - Google Patents

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

The present invention relates to a molded product.

Normally, a furnace material (heat insulating material) having a low heat capacity and thermal conductivity is provided inside a furnace such as an industrial furnace. Alkaline gas such as lithium gas and sodium gas may be generated from the object to be fired in the furnace, but there is a problem that the furnace material is easily worn by this alkaline gas. Therefore, as a furnace material, an inorganic molded body containing alumina, which can be excellent in durability, has been proposed (see Patent Document 1).

Although the above-mentioned furnace material has high strength and rigidity, flexibility may be required at the time of construction in the furnace (for example, when following the curved surface shape of the furnace). On the other hand, the furnace material is also required to have shape retention (specifically, shape retention after heating) so that the shape does not collapse due to vibration during use of the furnace.

Japanese Patent No. 5203920

The present invention has been made to solve the above problems, and one of the objects of the present invention is to provide a molded body having both flexibility and shape retention.

According to one aspect of the invention, a molded body is provided. This molded product contains an alumina fiber containing alumina, an inorganic binder, and a surfactant, and the content of the alumina is 70% by mass or more.

In one embodiment, the density of the molded product is 80 kg / m ³ or more and 200 kg / m ³ or less.

In one embodiment, the 30% compression restoration rate of the molded product is 85% or more.

In one embodiment, the shrinkage of the molded product at 1600 ° C. is 3% or less.

In one embodiment, the molded product comprises an organic binder.

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

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

In one embodiment, the surfactant comprises a cationic surfactant.

In one embodiment, the molded product is substantially free of refractory ceramic fibers.

In one embodiment, the molded product comprises a polymer flocculant.

In one embodiment, the above-mentioned polymer-based flocculants include a first polymer flocculant and a second polymer flocculant.

In one embodiment, the molded body contains alumina particles containing alumina, 30 parts by mass or more and 70 parts by mass or less of the alumina fiber, 30 parts by mass or more and 70 parts by mass or less of the alumina particles, and the interface. The activator is contained in a proportion of 0.1 parts by mass or more and 10 parts by mass or less.

In one embodiment, the molded body does not substantially contain alumina particles containing alumina, 80 parts by mass or more and 120 parts by mass or less of the alumina fiber, 5 parts by mass or less of the alumina particles, and the interface. The activator is contained in a proportion of 0.1 parts by mass or more and 10 parts by mass or less.

According to the present invention, it is possible to provide a molded body having both flexibility and shape retention.

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

A. Molded Body The molded body in one embodiment of the present invention contains an alumina fiber, an inorganic binder, and a surfactant.

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. According to such a content, for example, alkali resistance and a reduction-resistant atmosphere can be excellent.

Aluminous fibers may contain components other than alumina. Examples of other components include silica and zirconia.

The average length of the alumina fiber is preferably 100 μm to 100,000 μm, more preferably 1000 μm to 80,000 μm, and particularly preferably 3000 μm to 50,000 μm. The fiber diameter (diameter) of the alumina-based fiber is typically 3 μm to 12 μm, preferably 3 μm to 10 μm. The aspect ratio (length / diameter) of the alumina-based fiber is typically 25 or more.

The crystallinity of the alumina may be selected according to the characteristics required for the molded product, and two or more types of alumina fibers having different crystallinities of alumina may be used in combination. The crystallinity of alumina contained in the alumina fiber may be, for example, less than 30%, preferably less than 20%. Crystallinity in these ranges can contribute, for example, to improving the flexibility of the resulting molded product. Further, the crystallinity of alumina contained in the alumina fiber may be, for example, 30% or more, preferably 40% or more. The crystallinity in these ranges can contribute to, for example, improvement of the heat shrinkage rate and alkali resistance of the obtained molded product.

A-2. Inorganic Binder The inorganic binder can be formed of any suitable inorganic compound. As a specific example, the inorganic binder is formed of silica, zirconia, titania, alumina, bentonite and the like. These can be used alone or in combination of two or more. Among these, silica is preferably used. This is because the shape-retaining property of the obtained molded product (specifically, the shape-retaining property after heating) can be improved.

The content of the inorganic binder in the molded product is, for example, 10% by mass or less, preferably 5% by mass or less, and more preferably 3.5% by mass or less. With such a content, the flexibility of the obtained molded product can be further improved. On the other hand, the content of the inorganic binder in the molded product is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and more preferably 1% by mass or more. According to such a content, the shape-retaining property (specifically, the shape-retaining property after heating) of the obtained molded product can be further excellent.

A-3. Surfactant As the surfactant, any suitable surfactant can be used. Examples of the surfactant include anionic surfactant, cationic surfactant, amphoteric surfactant, and nonionic surfactant. These can be used alone or in combination of two or more. Among these, a cationic surfactant and / or an amphoteric surfactant is preferable, and a cationic surfactant is more preferably used. This is because the flexibility of the obtained molded product can be extremely excellent. Specifically, this is because it can be satisfactorily fixed to alumina (particularly, alumina fiber) that can be negatively charged in water during the production of the molded product described later.

Specific examples of the above-mentioned cationic surfactant include quaternary ammonium salt type, alkylamine salt type, and pyridinium salt type cationic surfactants. Examples of the quaternary ammonium salt type cationic surfactant include an alkyltrimethylammonium salt, a dialkyldimethylammonium salt, an alkylbenzalconium salt, N, N-dialkyloxyethyl-N-methyl, and N-hydroxy. Ethylammonium salt can be mentioned. Examples of the alkylamine salt type cationic surfactant include monoalkylamine salts, dialkylamine salts, trialkylamine salts and the like. Examples of the pyridinium salt-type cationic surfactant include an alkylpyridinium salt.

Examples of the cationic surfactant include stearate diethylaminoethylamide, stearate dimethylaminoethylamide, palmitate diethylaminoethylamide, palmitate dimethylaminoethylamide, myristinate diethylaminoethylamide, and myristine dimethylaminoethyl. Amide, behenic acid diethylaminoethylamide, behenic acid dimethylaminoethylamide, stearate diethylaminopropylamide, stearate dimethylaminopropylamide, palmitic acid diethylaminopropylamide, palmitate dimethylaminopropylamide, myristic acid diethylaminopropylamide, myristate dimethyl Examples thereof include amide amine compounds such as aminopropylamide, behenic acid diethylaminopropylamide and behenic acid dimethylaminopropylamide. These can be used alone or in combination of two or more.

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

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol tetra fatty acid ester, and glycerin fatty acid. Examples thereof include esters, sorbitan fatty acid esters, polyglycerin fatty acid esters, and sucrose fatty acid esters. These can be used alone or in combination of two or more.

The content of the surfactant 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. With such a content, the flexibility of the obtained molded product can be further improved. On the other hand, the content of the surfactant 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. For example, no significant difference is found in the flexibility of the obtained molded product.

A-4. Alumina Particles In one embodiment, the molded product contains alumina particles containing alumina (typically α-alumina). The alumina content of the aluminal particles is, for example, 98% by mass or more, preferably 99.5% by mass or more.

The average particle size of the aluminal 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-like particles is preferably 1 μm to 50 μm, more preferably 1 μm to 10 μm. The average particle size can be measured by a laser diffraction type particle size distribution measuring device.

By using the alumina-based particles, the amount of the alumina-based fibers used can be suppressed, for example, the cost can be reduced. The content of alumina particles in the molded product is, for example, 70% by mass or less, preferably 50% by mass or less. With such a content, for example, the densities described below can be well satisfied and excellent flexibility can be achieved. In one embodiment, the density of the resulting molded product is adjusted by adjusting the content of alumina particles.

A-5. Organic Binder Preferably, the molded product contains an organic binder. Examples of the organic binder include acrylic, methacrylic, styrene, butadiene and other resins and starch. Among these, acrylic type and methacrylic type are preferable. This is because the flexibility of the obtained molded product can be extremely excellent.

The content of the organic binder in the molded product is preferably 3% by mass or more and 12% by mass or less, and more preferably 6% by mass or more and 10% by mass or less. With such a content, the flexibility of the obtained molded product can be further improved. In one embodiment, the molded product is substantially free of the starch. Specifically, the starch content of the molded product is, for example, 1% by mass or less, preferably 0.1% by mass or less, and more preferably 0.01% by mass or less.

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

As the polymer flocculant, any suitable polymer flocculant can be used. Examples of the polymer flocculant include a cationic polymer flocculant, an anionic polymer flocculant, an amphoteric polymer flocculant, and a nonionic polymer flocculant. These can be used alone or in combination of two or more. In one embodiment, a first polymer flocculant (eg, anionic polymer flocculant) is used. In another embodiment, the first polymer flocculant (eg, anionic polymer flocculant) and the second polymer flocculant (eg, cationic polymer flocculant) are used in combination.

Examples of the cationic polymer flocculant include an acrylate-based polymer flocculant such as a polymer of a quaternized product of dimethylaminoethyl acrylate and a copolymer of a quaternized product of dimethylaminoethyl acrylate and acrylamide, and dimethylamino. Polypolymer containing a quaternized product of ethyl methacrylate, a methacrylate-based polymer flocculant such as a copolymer of a quaternized product of dimethylaminoethyl methacrylate and acrylamide, an amide group, a nitrile group, an amine hydrochloride, a formamide group, and the like. Examples thereof include amidin (amidine-based polymer flocculant) and Mannig modified products of polyacrylamide.

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.

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

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

The content of the polymer flocculant in the molded product is preferably 0.1% by mass or more, more preferably 0.15% by mass or more. On the other hand, the content of the polymer flocculant in the molded product is, for example, 5% by mass or less.

A-7. Inorganic flocculant The molded product may contain an inorganic flocculant. By using the inorganic flocculant, in the production of the molded product described later, the components contained in the slurry can be effectively aggregated to form flocs. Specifically, it can contribute to improving the fixability of the inorganic binder to alumina (particularly, alumina fiber).

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

A-8. Content The content of alumina in the molded product is, for example, 70% by mass or more, preferably 80% by mass or more, and particularly preferably 85% by mass or more. According to such a content, the alkali resistance of the obtained molded product can be excellent. In one embodiment, the alumina content of the molded product is 92% by mass or less. In another embodiment, the alumina content of the molded product is 95% by mass or less.

As described above, in one embodiment, the compact comprises the aluminal particles in addition to the aluminalous fibers. In this case, the molded body is, for example, 30 parts by mass or more and 70 parts by mass or less of alumina fibers, 30 parts by mass or more and 70 parts by mass or less of alumina particles, and 0.1 parts by mass or more and 10 parts by mass or less of a surfactant. Include in proportion. The content of the aluminal particles is preferably 40 parts by mass or more and 230 parts by mass or less, and more preferably 60 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the aluminalic fibers. The content of the surfactant is preferably 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass in total of the alumina fiber and the alumina particles.

In another embodiment, the molded product is substantially free of alumina particles. For example, the molded body contains 80 parts by mass or more and 120 parts by mass or less of alumina fibers, 5 parts by mass or less of alumina particles, and 0.1 parts by mass or more and 10 parts by mass or less of a surfactant. The content of the surfactant is preferably 0.1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the alumina fiber.

The molded product is preferably substantially free of refractory ceramic fibers (RCF). Here, "substantially free" means that the content of RCF in the molded product is 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.05% by mass or less. Particularly preferably, it is 0.01% by mass or less. RC F typically comprises alumina and silica. The alumina content of RC F is typically 30% by mass to 60% by mass, preferably 40% by mass to 60% by mass. The silica content of RC F is typically 40% by mass to 60% by mass. The fiber diameter (diameter) of RC F is typically 1 μm to 3 μm. A molded product containing such an RCF may have both flexibility and shape retention, but is substantially free of RCF (for example, using the above-mentioned alumina fiber which is easily brittle by heating and is thick, as described above. It is one of the features of the present invention that a molded product having both flexibility and shape retention can be realized (while having a high alumina content).

B. Physical characteristics of the molded product The density of the molded product is preferably 80 kg / m ³ or more and 200 kg / m ³ or less, and more preferably 100 kg / m ³ or more and 150 kg / m ³ or less. By having such a density, for example, excellent flexibility and shape retention can be achieved.

The 30% compression restoration rate of the molded product is, for example, 85% or more. In one embodiment, the 30% compression restoration rate of the molded product is preferably 92% or more. In another embodiment, the 30% compression restoration rate of the molded product is preferably 90% or more. It is one of the features of the present invention that it can have such a high restoration rate. According to such a compression / restoration rate, the flexibility can be extremely excellent.

The heat shrinkage rate (shrinkage rate at 1600 ° C.) of the molded product is preferably 3% or less, and may be 2% or less. According to such a heat shrinkage rate, it can be satisfactorily used as a furnace material, for example.

C. Method for manufacturing a molded product The molded product is manufactured by any suitable method. In one embodiment, the method for producing the molded product is to add the alumina fiber, the inorganic binder and the surfactant to the dispersion medium to obtain a slurry, and to obtain a wet molded product from the obtained slurry. Includes obtaining and drying the resulting wet molded body.

C-1. Preparation of slurry Any suitable dispersion medium can be used as the dispersion medium. Examples of the dispersion medium include distilled water, ion-exchanged water, tap water, groundwater, water such as industrial water, and polar organic solvents. Examples of the polar organic solvent include monohydric alcohols such as ethanol and propanol, and divalent alcohols such as ethylene glycol. Among these, water is preferable because it does not deteriorate the working environment and has no burden on the environment.

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

If necessary, an organic binder such as the alumina particles, the polymer flocculant, the inorganic flocculant, the resin, and starch is added to the dispersion medium. These may be in the form of solids, dispersions or solutions 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).

In one embodiment, the amount of the colloidal sol added to the dispersion medium is 0.5 parts by mass or more and 3 parts by mass or less in terms of solid content with respect to 100 parts by mass in total of the alumina fiber and the alumina particles. It is preferable, more preferably 1 part by mass or more and 2 parts by mass or less. In another embodiment, it is preferably 2 parts by mass or more and 6 parts by mass or less in terms of solid content, and more preferably 3 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of alumina fiber.

The total solid content concentration (slurry concentration) contained in the slurry 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. It is 3% by mass or less.

The wet molded body is typically obtained by dehydration molding or papermaking of the slurry.

The dehydration molding can be performed by any suitable method. Specific examples thereof include a suction dehydration molding method in which a slurry is poured into a molding mold having a net installed at the bottom and the dispersion medium is sucked, and a pressure dehydration molding method. In this specification, it is referred to as dehydration molding including the case where a dispersion medium other than water is used.

The above papermaking can be performed by any suitable method. Specific examples include a flow-on method in which a slurry is poured from a flow box onto a strip-shaped porous carrier, a Hacheck-type papermaking method, a long net-type papermaking method, and other methods capable of continuously making a slurry.

The wet molded product preferably has a shape similar to the desired molded product. Examples of the shape of the molded body include a board shape, a sheet shape, and a block shape.

Any suitable method can be adopted as the method for drying the wet-molded article. 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.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

[Example 1-1]
To water, 1 part by mass of a cationic surfactant (texture improver "FS8006" manufactured by Seiko PMC) in terms of solid content was added and stirred. Here, 45 parts by mass of alumina fiber (“Denca Arsen B80” manufactured by Denka Co., Ltd., alumina content ratio 80% by mass, silica content ratio 20% by mass), alumina particles (“SA31” manufactured by Nippon Light Metal Co., Ltd., average grain). Diameter: 5 μm) 55 parts by mass, colloidal silica (“Silica Doll 30” manufactured by Nippon Kagaku Kogyo Co., Ltd., suspension with a solid content of 30% by mass, average particle size of solid content: 15 nm, pH: 10.0) is solid. 1.5 parts by mass in minutes, resin ("Aron Tuck HV-C9081" manufactured by Toa Synthetic Co., Ltd., acrylic polymer 57-61% by mass, water 39-43% by mass, pH: 5.0-7.0, viscosity : 50 to 1,500 mPa · s, Tg: −41 ° C.) 7.5 parts by mass, and polyacrylic acid (“Polystron 705” manufactured by Arakawa Chemical Industry Co., Ltd., cationic, non-volatile content 10% by mass, pH: After adding 0.2 parts by mass (2.5 to 3.5, viscosity: 300 to 1000 cps), polyacrylamide ("30A113" manufactured by Asada Chemical Industry Co., Ltd., anionic, 0.1% by mass aqueous solution, PH: 6 to 8) 0.1 part by mass was added, water was further added so that the obtained slurry concentration was 2% by mass, and the mixture was stirred to obtain a slurry.

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

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

[Example 2-1]
To water, 1.1 parts by mass of a cationic surfactant (texture improver "FS8006" manufactured by Seiko PMC) in terms of solid content was added and stirred. Here, 100 parts by mass of alumina fiber (“Denca Arsen B97N5” manufactured by Denka Co., Ltd., alumina content ratio 97% by mass, silica content ratio 3% by mass), colloidal silica (“Silica Doll 30” manufactured by Nippon Chemical Industry Co., Ltd.), Suspension with 30% by mass of solid content, average particle size of solid content: 15 nm, pH: 10.0) in 4 parts by mass in terms of solid content, inorganic flocculant (liquid aluminum sulfate, aluminum sulfate manufactured by Daimei Chemical Industry Co., Ltd.) Concentration 23.5 to 27.5% by mass) 3 parts by mass, resin ("Arontack HV-C9081" manufactured by Toa Synthetic Co., Ltd., acrylic polymer 57 to 61% by mass, water 39 to 43% by mass, pH: 5.0 ~ 7.0, viscosity: 50 ~ 1,500 mPa · s, Tg: −41 ° C.) 7.5 parts by mass, and polyacrylamide (“30A113” manufactured by Asada Chemical Industry Co., Ltd., anionic, 0.1% by mass aqueous solution , PH: 6-8) After adding 0.2 parts by mass, water was added and stirred so that the obtained slurry concentration was 2% by mass to obtain a slurry.

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

[Example 2-2] to [Example 2-5]
Molds 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 described later.

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

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

[Comparative Example 3]
In water, 60 parts by mass of alumina fibers (“Denca Arsen B97N5” manufactured by Denka, 97% by mass of alumina, 3% by mass of silica content), alumina particles (“A11” manufactured by Nippon Light Metal Co., Ltd., average grains). 40 parts by mass (diameter: 50 μm), colloidal silica (“Silica Doll 30” manufactured by Nippon Kagaku Kogyo Co., Ltd., suspension with a solid content of 30% by mass, average particle size of solid content: 15 nm, pH: 10.0) is solid. 8 parts by mass in terms of minutes, 4 parts by mass of starch (“Petrosize J” manufactured by Nissho Chemical Co., Ltd.) and polyacrylamide (“Polystron 311” manufactured by Arakawa Chemical Industry Co., Ltd., cationic, non-volatile content: 10% by mass, pH: 4.2 to 4.8, viscosity: 500 to 1500 cps) were added at a ratio of 3 parts by mass, and then water was added and stirred so that the obtained slurry concentration was 2% by mass to obtain a slurry.

Next, the obtained slurry was dehydrated by a suction dehydration molding method in which the slurry was poured into a molding die having a net installed at the bottom and water was sucked to obtain a board-shaped wet molded body.

Next, the obtained wet molded product was dried at 110 ° C. for 36 hours to obtain a board-shaped molded product.

[Reference example]
60 parts by mass of alumina fiber ("Denca Arsen B80" manufactured by Denka, 80% by mass of alumina content, 20% by mass of silica content), RCF ("Fineflex 1300 bulk" manufactured by Nichias, 50% by mass) in water. %, Silica content 50% by mass) 40 parts by mass, resin ("Arontuck HV-C9081" manufactured by Toa Synthetic Co., Ltd., acrylic polymer 57-61% by mass, water 39-43% by mass, pH: 5.0-7 .0, viscosity: 50 to 1,500 mPa · s, Tg: -41 ° C) 5.0 parts by mass, inorganic flocculant (liquid aluminum sulfate manufactured by Daimei Chemical Industry Co., Ltd., aluminum sulfate concentration 23.5 to 27.5 mass) %) 1.3 parts by mass and polyacrylic acid (“Polystron 705” manufactured by Arakawa Chemical Industry Co., Ltd., cationic, non-volatile content 10% by mass, pH: 2.5 to 3.5, viscosity: 300 to 1000 cps) After adding 0.06 parts by mass, water was further added and stirred so that the obtained slurry concentration was 2% by mass to obtain a slurry.
The slurry was dehydrated to obtain a board-shaped wet molded product, and then dried at 110 ° C. for 12 hours to obtain a molded product.

<Evaluation method>
The following evaluation was performed on the obtained molded body.
(1) Density The obtained molded body was processed into a plate shape as needed to prepare a sample for measurement. The mass M (kg) of the measurement sample was measured with a scale. The volume V (m ³ ) of the sample for measurement was determined using a caliper, a steel tape measure, a steel straightedge, or a non-contact measuring machine (laser displacement meter, rangefinder). From these values, the density M / V (kg / m ³ ) was obtained (rounded to the first decimal place to obtain an integer value).
(2) 30% compression restoration rate With a compression tester (“Autograph AG-Xplus” manufactured by Shimadzu Corporation, load cell capacity: 50 kN, jig: φ100 mm fixed pressure plate), the upper and lower pressure plates are in contact with each other, and the stress is 0. The displacement of 20N was set to the 0 position. From the obtained molded body, a test piece having a thickness of 50 mm, a width of 50 mm, and a length of 50 mm is cut out, the test piece is sandwiched between the upper and lower pressure plates of the compression tester, and the test piece is set so that the compression stress is 0.20 N. The displacement when set was defined as the test piece thickness T1. Then, the compression tester was lowered at a speed of 5 mm / min. To compress 30% of the thickness of the test piece, and then held at the 30% compression position for 5 minutes. After holding, the compression tester is raised at a speed of 5 mm / min. To release the compression of the test piece, and when the compression is released, the pressure plate and the test piece are separated from each other, and the test piece is allowed to stand for 5 minutes from the time when the compressive stress becomes 0. did. After standing still, the compression tester was lowered again, the displacement at which the compressive stress was 0.20 N was defined as the test piece thickness T2, and the compression restoration rate (%) was calculated by the formula: T2 / T1 × 100 (decimal point 1). Was rounded off to an integer value).
(3) Heat shrinkage rate A test piece having a thickness of 50 mm, a width of 50 mm, and a length of 150 mm is cut out from the obtained molded body, and the length L1 of the test piece is measured with a caliper. After that, a heating test of the test piece was performed in an electric furnace. Specifically, the temperature was raised at a rate of about 200 ° C./h, the temperature was maintained at 1600 ° C. for 3 hours, the power of the electric furnace was turned off, and the mixture was naturally cooled in the furnace. The length L2 of the test piece after the heating test was measured, and the heating shrinkage rate (%) was calculated by the formula: {(L1-L2) / L1} × 100 (rounded to the first decimal place of the calculated value). ..
(4) Shape retention after heating It was confirmed whether the obtained molded body could 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 are as follows.
<Evaluation criteria>
〇: Can be handled, and there is little scattering of alumina fibers and particles.
Δ: Handleable, but a lot of alumina fibers and particles are scattered.
×: Unable to handle.
(5) Flexibility (tactile sensation)
The evaluation was made based on the feel of the obtained molded product by hand. The evaluation criteria are as follows.
<Evaluation criteria>
〇: Soft and resilient.
Δ: Soft, but not resilient.
×: Hard.

The evaluation results are summarized in Table 1.

The molded product of the present invention can be used as a heat-resistant material and a heat insulating material for various purposes. For example, it is suitably used as a furnace material. Specifically, it is suitably used as a furnace material for industrial furnaces such as firing furnaces for electronic parts, crematoriums, and physics and chemistry furnaces.

Claims (13)

Alumina fibers containing alumina and
With an inorganic binder,
Containing, with surfactant,
The alumina content is 70% by mass or more.
Molded body. The molded product according to claim 1, wherein the density is 80 kg / m ³ or more and 200 kg / m ³ or less. The molded product according to claim 1 or 2, wherein the 30% compression restoration rate is 85% or more. The molded product according to any one of claims 1 to 3, wherein the shrinkage rate at 1600 ° C. is 3% or less. The molded product according to any one of claims 1 to 4, which comprises an organic binder. The molded product according to any one of claims 1 to 5, wherein the content of the inorganic binder is 5% by mass or less. The molded product according to any one of claims 1 to 6, wherein the content of the inorganic binder is 1% by mass or more. The molded product according to any one of claims 1 to 7, wherein the surfactant contains a cationic surfactant. The molded product according to any one of claims 1 to 8, which is substantially free of refractory ceramic fibers. The molded product according to any one of claims 1 to 9, which comprises a polymer flocculant. The molded product according to claim 10, wherein the polymer-based flocculant contains a first polymer flocculant and a second polymer flocculant. Contains alumina-containing particles containing alumina,
The claim comprises 30 parts by mass or more and 70 parts by mass or less of the alumina fiber, 30 parts by mass or more and 70 parts by mass or less of the alumina particles, and 0.1 part by mass or more and 10 parts by mass or less of the surfactant. The molded body according to any one of 1 to 11. Substantially free of alumina-containing particles containing alumina
13. The molded body according to any one.