CN116406436A

CN116406436A - Molded body

Info

Publication number: CN116406436A
Application number: CN202180075486.3A
Authority: CN
Inventors: 小野泰; 森田弘树; 米内山贤
Original assignee: Nichias Corp
Current assignee: Nichias Corp
Priority date: 2020-11-27
Filing date: 2021-09-03
Publication date: 2023-07-07
Also published as: WO2022113465A1; JP2022085606A; KR20230096082A

Abstract

The invention provides a molded article having both flexibility and shape retention. A shaped body, comprising: alumina fiber containing alumina; an inorganic binder; and a surfactant, wherein the content of the alumina is 70 mass% or more.

Description

Molded body

Technical Field

The present invention relates to a molded article.

Background

In general, a furnace material (heat insulating material) having low heat capacity and low heat conductivity is provided in an interior of an industrial furnace or the like. In the furnace, there is a possibility that an alkali gas such as lithium gas or sodium gas is generated from the fired material, there is a problem in that the furnace is easily worn out by the alkali gas. Then, as a furnace material, an inorganic molded body containing alumina excellent in durability has been proposed (see patent document 1).

The furnace material has high strength and rigidity, but flexibility may be required when it is applied to the furnace (for example, when it is formed along a curved surface of the furnace). On the other hand, in order to prevent the shape from being distorted by vibration or the like during use of the furnace, the furnace material is also required to have shape retention (specifically, shape retention after heating).

Prior art literature

Patent literature

Patent document 1: japanese patent No. 5203920

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above problems, and an object thereof is to provide a molded article having both flexibility and shape retention.

Means for solving the problems

According to one aspect of the present invention, there is provided a molded body. The molded article comprises: alumina fiber containing alumina; an inorganic binder; and a surfactant, wherein the content of the alumina is 70 mass% or more.

In one embodiment, the molded body has a density of 80kg/m ³ 200kg/m above ³ The following is given.

In one embodiment, the molded article has a 30% compression recovery of 85% or more.

In one embodiment, the molded article has a shrinkage of 3% or less at 1600 ℃.

In one embodiment, the molded article includes an organic binder.

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

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

In one embodiment, the surfactant comprises a cationic surfactant.

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

In one embodiment, the molded article contains a polymer coagulant.

In one embodiment, the polymer-based coagulant includes a first polymer coagulant and a second polymer coagulant.

In one embodiment, the molded article comprises alumina particles containing alumina, the alumina fibers are contained in an amount of 30 to 70 parts by mass, the alumina particles are contained in an amount of 30 to 70 parts by mass, and the surfactant is contained in an amount of 0.1 to 10 parts by mass.

In one embodiment, the molded article contains substantially no alumina particles containing alumina, 80 to 120 parts by mass of the alumina fibers, 5 to 10 parts by mass of the alumina particles, and 0.1 to 10 parts by mass of the surfactant.

Effects of the invention

According to the present invention, a molded article having both flexibility and shape retention can be provided.

Detailed Description

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

A. Molded body

The molded article in one embodiment of the present invention contains alumina fibers, 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. With such a content, for example, alkali resistance and reducing atmosphere resistance can be excellent.

The alumina fiber may contain other components than alumina. Examples of the other component include silica and zirconia.

The average length of the alumina fiber is preferably 100 μm to 100000 μm, more preferably 1000 μm to 80000 μm, and particularly preferably 3000 μm to 50000 μm. The alumina fiber has a fiber diameter (diameter) of typically 3 μm to 12. Mu.m, preferably 3 μm to 10. Mu.m. The aspect ratio (length/diameter) of the alumina fiber is typically 25 or more.

The crystallinity of the alumina may be selected according to the characteristics required for the molded article, and two or more kinds of alumina fibers having different crystallinity 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%. These ranges of crystallinity can contribute to, for example, improvement in flexibility of the obtained molded article. The crystallinity of alumina contained in the alumina fiber may be, for example, 30% or more, and preferably 40% or more. These ranges of crystallinity can contribute to, for example, improvement in heat shrinkage and alkali resistance of the molded article obtained.

A-2 inorganic adhesive

The inorganic binder may be formed of any suitable inorganic compound. As specific examples, the inorganic binder is formed of silica, zirconia, titania, alumina, bentonite, or the like. They may be used alone or in combination of two or more. Among them, silica is preferably used. This is because the obtained molded article can have more excellent shape retention (specifically, shape retention after heating).

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

A-3 surfactant

As the surfactant, any suitable surfactant may be used. Examples of the surfactant include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. They may be used alone or in combination of two or more. Among them, a cationic surfactant and/or an amphoteric surfactant are preferable, and a cationic surfactant is further preferable. This is because the molded article obtained can be extremely excellent in softness. Specifically, this is because: in the production of a molded article described later, the molded article can be favorably fixed to alumina (particularly, alumina fibers) which can be negatively charged in water.

Specific examples of the 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 alkyl trimethyl ammonium salt, dialkyl dimethyl ammonium salt, alkyl benzalkonium salt, N-dialkoxyethoxy-N-methyl, and N-hydroxyethyl ammonium salt. Examples of the alkylamine-type cationic surfactant include monoalkyl amine salts, dialkyl amine salts, and trialkyl amine salts. Examples of the cationic surfactant of the pyridinium salt include alkylpyridinium salts.

Examples of the cationic surfactant include amide compounds such as diethylaminoethyl stearate, dimethylaminoethyl stearate, diethylaminoethyl palmitate, dimethylaminoethyl palmitate, diethylaminoethyl myristate, dimethylaminoethyl myristate, diethylaminoethyl behenate, dimethylaminoethyl behenate, diethylaminopropyl stearate, dimethylaminopropyl stearate, diethylaminopropyl palmitate, dimethylaminopropyl palmitate, diethylaminopropyl myristate, dimethylaminopropyl myristate, diethylaminopropyl behenate, and dimethylaminopropyl behenate. They may be used alone or in combination of two or more.

Specific examples of the amphoteric surfactant include betaine-type, imidazoline-type, amino acid-type, and amine oxide-type amphoteric surfactants. Examples of the betaine type amphoteric surfactant include alkyl betaines, fatty acid amidopropyl betaines, lauryl hydroxysulfobetaines, alkyl hydroxysulfobetaines, lecithins, and hydrogenated lecithins. Examples of the imidazoline-type amphoteric surfactant include 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolium betaine, 2-alkyl-1- (2-hydroxyethyl) imidazolium-1-acetate, and sodium undecyl hydroxyethyl imidazolium betaine. Examples of the amphoteric surfactant include alkyl diethylene triamine acetate, alkoxyhydroxypropyl arginine hydrochloride, sodium lauryl amino diacetate, dihydroxyalkyl methyl glycine, sodium lauryl diaminoethyl glycine, lauriminodipropionic acid, N- [ 3-alkoxy-2-hydroxypropyl ] -L-arginine hydrochloride, and sodium alkylamino dipropionate. The amine oxide type amphoteric surfactant includes, for example, alkyl dimethyl amine oxide. They may 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, glycerin fatty acid ester, sorbitan fatty acid ester, polyglycerin fatty acid ester, and sucrose fatty acid ester. They may be used alone or in combination of two or more.

The content of the surfactant in the molded article 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. The softness of the molded article obtained can be further improved by the content. On the other hand, the content of the surfactant in the molded article is, for example, 10 mass% or less, preferably 5 mass% or less, more preferably 3 mass% or less, and particularly preferably 1.5 mass% or less. This is because, for example, a large difference in flexibility of the obtained molded article is not observed.

A-4 alumina particles

In one embodiment, the molded article includes alumina particles containing alumina (typically, α -alumina). The content of alumina in the alumina particles is, for example, 98 mass% or more, preferably 99.5 mass% or more.

The average particle diameter of the alumina particles is typically 1 μm to 100. Mu.m. For example, the average particle diameter of the alumina particles is preferably 1 μm to 50 μm, more preferably 1 μm to 10 μm, from the viewpoint of shape retention after heating. The average particle diameter can be measured by a laser diffraction type particle size distribution measuring device.

By using the alumina particles, the amount of the alumina fibers used can be suppressed, and for example, the cost can be reduced. The content of alumina particles in the molded article is, for example, 70 mass% or less, preferably 50 mass% or less. Such a content can satisfactorily satisfy the density described later, and can achieve excellent flexibility. In one embodiment, the density of the obtained molded article is adjusted by adjusting the content of alumina particles.

A-5 organic adhesive

Preferably, the molded article contains an organic binder. Examples of the organic binder include resins such as acrylic, methacrylic, styrene and butadiene resins and starches. Among them, acrylic and methacrylic are preferable. This is because the molded article obtained can be extremely excellent in softness.

The content of the organic binder in the molded article is preferably 3 mass% or more and 12 mass% or less, more preferably 6 mass% or more and 10 mass% or less. The softness of the molded article obtained can be further improved by the content. In one embodiment, the shaped body is substantially free of the starch described above. Specifically, the content of starch in the molded article 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 coagulant

Preferably, the molded article contains a polymer coagulant. By using the polymer flocculant, the components contained in the slurry can be efficiently coagulated to form flocculates in the production of molded articles described later.

Any suitable polymer flocculant may be used as the polymer flocculant. Examples of the polymer flocculant include cationic polymer flocculants, anionic polymer flocculants, amphoteric polymer flocculants, and nonionic polymer flocculants. They may be used alone or in combination of two or more. In one embodiment, a first polymeric coagulant (e.g., an anionic polymeric coagulant) may be used. In another embodiment, the first polymeric coagulant (e.g., anionic polymeric coagulant) and the second polymeric coagulant (e.g., cationic polymeric coagulant) may be used in combination.

Examples of the cationic polymer flocculant include acrylate-based polymer coagulants such as polymers of quaternary compounds of dimethylaminoethyl acrylate, copolymers of quaternary compounds of dimethylaminoethyl acrylate and acrylamide, polymers of quaternary compounds of dimethylaminoethyl methacrylate, methacrylate-based polymer coagulants such as copolymers of quaternary compounds of dimethylaminoethyl methacrylate and acrylamide, polyvinyl amidines (amidine-based polymer coagulants) containing an amide group, a nitrile group, amine hydrochloride, an amide group, and the like, and mannich-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 copolymers of acrylamide and acrylic acid and quaternized dimethylaminomethyl methacrylate.

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

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

A-7 inorganic coagulant

The molded article may contain an inorganic coagulant. By using an inorganic coagulant, the components contained in the slurry can be efficiently coagulated to form flocculates in the production of molded articles described later. Specifically, the inorganic binder can contribute to an improvement in the fixation of the inorganic binder to alumina (particularly, alumina fibers).

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

A-8 content

The content of alumina in the molded article is, for example, 70 mass% or more, preferably 80 mass% or more, and particularly preferably 85 mass% or more. With such a content, the alkali resistance of the obtained molded article can be excellent. In one embodiment, the alumina content of the molded body is 92 mass% or less. In another embodiment, the alumina content of the molded body is 95 mass% or less.

As described above, in one embodiment, the molded article contains the alumina particles in addition to the alumina fibers. In this case, the molded article contains, for example, alumina fiber in a proportion of 30 to 70 parts by mass, alumina particles in a proportion of 30 to 70 parts by mass, and a surfactant in a proportion of 0.1 to 10 parts by mass. The content of the alumina particles is preferably 40 parts by mass or more and 230 parts by mass or less, more preferably 60 parts by mass or more and 150 parts by mass or less, based on 100 parts by mass of the alumina fibers. The content of the surfactant is preferably 0.1 to 10 parts by mass based on 100 parts by mass of the total of the alumina fibers and the alumina particles.

In another embodiment, the shaped body is substantially free of alumina particles. For example, the molded article contains 80 to 120 parts by mass of the alumina fiber, 5 parts by mass of the alumina particles, and 0.1 to 10 parts by mass of the 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 shaped body is preferably substantially free of Refractory Ceramic Fibers (RCF). Here, "substantially free" means that the content of RCF in the molded article 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. The RCF typically comprises alumina and silica. The content of alumina in the RCF is typically 30 to 60% by mass, preferably 40 to 60% by mass. The content of the silica in the RCF is typically 40 to 60 mass%. The fiber diameter (diameter) of RCF is typically 1 μm to 3. Mu.m. Although a molded article containing such an RCF can have both flexibility and shape retention, a molded article that does not substantially contain an RCF (for example, uses the alumina fiber that is easily embrittled and coarse by heating, and has the high content of alumina) and can have both flexibility and shape retention is one of the features of the present invention.

B. Physical Properties of molded article

The density of the molded article is preferably 80kg/m ³ 200kg/m above ³ Hereinafter, it is more preferably 100kg/m ³ Above and 150kg/m ³ The following is given. By having such a density, for example, excellent flexibility and shape retention can be achieved.

The compression recovery rate of the molded article at 30% is, for example, 85% or more. In one embodiment, the compression recovery rate of the molded article at 30% is preferably 92% or more. In another embodiment, the compression recovery rate of the molded article at 30% is preferably 90% or more. It is one of the features of the present invention that such a high recovery rate can be achieved. The soft property can be extremely excellent according to such a compression recovery rate.

The heat shrinkage (shrinkage at 1600 ℃) of the molded article is preferably 3% or less, but may be 2% or less. Such a heat shrinkage rate can be used favorably as a furnace material, for example.

C. Method for producing molded article

The molded article can be produced by any suitable method. In one embodiment, the method for manufacturing the molded article includes the steps of: adding the alumina fiber, the inorganic binder and the surfactant to a dispersion medium to obtain a slurry; obtaining a wet compact from the obtained slurry; and drying the obtained wet compact.

C-1 preparation of slurry

As the dispersion medium, any suitable dispersion medium may be used. 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 them, water is preferable in view of no deterioration of the working environment and no load on the environment.

When the inorganic binder is added to the dispersion medium, the inorganic binder may be in the form of a solid or in the form of 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 solution.

The dispersion medium may optionally contain an organic binder such as alumina particles, the polymer flocculant, the inorganic flocculant, the resin, or starch. When added to the dispersion medium, they may be in the form of solid or in the form of dispersion or solution. The coagulant 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 preferably 0.5 parts by mass or more and 3 parts by mass or less, more preferably 1 part by mass or more and 2 parts by mass or less in terms of solid content, per 100 parts by mass of the total of the alumina fibers and the alumina particles. In another embodiment, the amount of the alumina fiber is preferably 2 parts by mass or more and 6 parts by mass or less, more preferably 3 parts by mass or more and 5 parts by mass or less, in terms of solid content, per 100 parts by mass of the alumina fiber.

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

Typically, the wet molded product is obtained by dewatering the slurry or by papermaking.

The dehydration molding may be performed by any suitable method. Specific examples thereof include a suction dehydration molding method and a press dehydration molding method in which a slurry is poured into a molding die having a net at the bottom and the dispersion medium is sucked. In the present specification, the term "dehydration molding" is also used to include the case of using a dispersion medium other than water.

The above-described papermaking may be carried out by any suitable method. Specific examples thereof include a downstream (Flow on) method of flowing a slurry from a headbox onto a belt-shaped porous support, a Hatschek (Hatschek) method, a fourdrinier method, and the like, in which the slurry can be continuously manufactured.

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

Any suitable method can be used for drying the wet compact. The drying temperature is, for example, 40℃to 180℃and preferably 60℃to 150℃and more preferably 80℃to 120℃and particularly preferably 100℃to 120 ℃. The drying time is, for example, 6 to 48 hours, preferably 8 to 40 hours, more preferably 10 to 36 hours, particularly preferably 12 to 20 hours.

Examples

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

Examples 1 to 1

1 part by mass of a cationic surfactant (feeling improver "FS8006" manufactured by starlight PMC corporation) was added to water in terms of solid content, and stirred. 45 parts by mass of alumina fiber (80% by mass of alumina content and 20% by mass of Silica content, manufactured by Kagaku Co., ltd.), 55 parts by mass of alumina particles (5 μm average particle diameter: SA31, manufactured by light metal Co., ltd.), 1.5 parts by mass of colloidal Silica (10% by mass of Silica Doll 30, manufactured by chemical industry Co., ltd.), 30% by mass of a suspension having a solid content, 15nm average particle diameter of solid content, pH 10.0), resin (57 to 61% by mass of acrylic polymer, 39 to 43% by mass of water, 5.0 to 7.0, 50 to 1500 mPas, tg: -41 ℃) and polyacrylic acid (10% by mass of POLYSTRON 705, manufactured by Sichuan chemical Co., ltd.), 0.113% by mass of polyacrylic acid (2.5 to 3.5, 300.1000 cps average particle diameter: 15nm, pH 10.0), and 0.113% by mass of aqueous slurry having a viscosity of 0 to 0% by mass of acrylic acid, and 1% by mass of aqueous solution having a water concentration of 0% to be mixed, are added thereto, and the aqueous slurry is obtained.

The slurry was dehydrated to obtain a wet compact in the form of a plate, and then dried at 110℃for 12 hours to obtain a compact.

Examples 1-2 to examples 1-4

The procedure of example 1-1 was repeated except that an inorganic coagulant (liquid aluminum sulfate, aluminum sulfate concentration: 23.5 to 27.5 mass%) was added and the formulation was changed as described in table 1 below, to obtain molded bodies of examples 1-2 to 1-4.

Examples 2 to 1

1.1 parts by mass of a cationic surfactant (feeling improver "FS8006" manufactured by starlight PMC corporation) was added to water in terms of solid content, and stirred. 100 parts by mass of alumina fiber (manufactured by Kagaku Co., ltd., "DENKA ALCEN B97N5", alumina content: 97% by mass, silica content: 3% by mass), 4 parts by mass of colloidal Silica (manufactured by Japanese chemical industry Co., ltd., "Silica dol 30", suspension having a solid content of 30% by mass, average particle diameter of solid content: 15nm, pH: 10.0), 3 parts by mass of inorganic coagulant (manufactured by Ming chemical industry Co., ltd., "ARONTACHV-C9081", acrylic polymer: 57 to 61% by mass, 39 to 43% by mass, pH:5.0 to 7.0, viscosity: 50 to 1500mPa s, tg: -41 ℃) 7.5 parts by mass, and polyacrylamide (manufactured by shallow chemical industry Co., ltd., "30A113", anion, 0.1% by mass aqueous solution, pH:6 to 8.2) were added thereto, and the resulting slurry was stirred to give a slurry having a concentration of 2% by mass.

Examples 2-2 to 5

The same procedure as in example 2-1 was repeated except that the formulation was changed as described in Table 1 below, to obtain molded articles of examples 2-2 to 2-5.

Comparative example 1

A molded article was obtained in the same manner as in example 1-2, except that colloidal silica was not used.

Comparative example 2

A molded article was obtained in the same manner as in example 2-2, except that a surfactant was not used.

Comparative example 3

To water were added 60 parts by mass of alumina fiber (DENKA ALCEN B97N5, manufactured by Kagaku Co., ltd., alumina content: 97% by mass, silica content: 3% by mass), 40 parts by mass of alumina particles (A11, average particle diameter: 50 μm, manufactured by light metal Co., ltd.), 8 parts by mass of colloidal Silica (Silica Doll 30, manufactured by chemical industry Co., ltd., suspension having a solid content of 30% by mass, average particle diameter: 15nm, pH:10.0, manufactured by chemical industry Co., ltd.), 4 parts by mass of starch (Petrosize J, manufactured by chemical industry Co., ltd.), and 3 parts by mass of polyacrylamide (POSTRON 311, cationic nonvolatile component: 10% by chemical industry Co., ltd., pH:4.2 to 4.8, viscosity: 500 to 1500 cps), and then water was added so that the obtained slurry concentration became 2% by mass, followed by stirring, to obtain a slurry.

Next, the obtained slurry was poured into a forming die having a net at the bottom, and dehydrated by a suction dehydration method for sucking water, to obtain a plate-like wet formed body.

Subsequently, the wet molded body thus obtained was subjected to a drying treatment at 110℃for 36 hours to obtain a plate-like molded body.

Reference example

60 parts by mass of alumina fiber (DENKA ALCEN B80, 80% by mass of alumina, 20% by mass of silica) manufactured by Kabushiki Kaisha, 50% by mass of RCF (FINEFLEX 1300Bulk, 50% by mass of silica), 40 parts by mass of resin (ARONTAC HV-C9081, 57-61% by mass of acrylic polymer, 39-43% by mass of water, pH 5.0-7.0, viscosity 50-1500 mPas, tg: -41 ℃) 5.0 parts by mass, 1.3 parts by mass of inorganic coagulant (liquid aluminum sulfate, aluminum sulfate concentration 23.5-27.5% by mass) manufactured by Dain Kaisha chemical industry Co., ltd.) and 0.06 parts by mass of polyacrylic acid (POSTRON 705, cationic, nonvolatile component 10% by mass, pH 2.5-3.5, viscosity 300-1000 cps) were added to water, and the mixture was stirred to obtain a slurry having a concentration of 2% by mass.

< evaluation method >

The obtained molded article was evaluated as follows.

(1) Density of

The obtained molded article was processed into a plate shape as needed to prepare a measurement sample. The mass M (kg) of the measurement sample was measured by a scale. The volume V (m) of the measurement sample was determined by using a vernier caliper, a steel tape, a steel ruler, or a non-contact measuring machine (laser displacement meter, distance meter) ³ ). From these values, the density M/V (kg/M ³ ) (decimal point bit 1 is rounded to set an integer value).

(2) 30% compression recovery

The displacement at which the stress reaches 0.20N was set to the 0 position by the contact between the upper and lower platens using a compression tester (AUTOGRAPH AG-Xplus manufactured by Shimadzu corporation; load cell capacity: 50 kN; fixture: 100mm fixed platen). From the obtained molded body, a test piece having a thickness of 50mm×a width of 50mm×a length of 50mm was cut out, the test piece was held between upper and lower platens of a compression tester, the test piece was set so that the compressive stress became 0.20N, and the displacement at the time of setting was regarded as a test piece thickness T1. Thereafter, the compression tester was lowered at a speed of 5 mm/min, and after 30% of the thickness of the test piece was compressed, it was held at the 30% compression position for 5 minutes. After the holding, the compression tester was raised at a speed of 5 mm/min to release the compression of the test piece, and at the time of the compression release, the pressure plate was separated from the test piece and allowed to stand for 5 minutes from the time when the compression stress reached 0. After standing, the compression tester was lowered again, and the displacement at which the compressive stress became 0.20N was set as the test piece thickness T2, by the formula: the compression recovery (%) was calculated by T2/t1×100 (the 1 st bit of the decimal point was rounded to be set as an integer value).

(3) Shrinkage under heating

From the obtained molded body, a test piece having a thickness of 50 mm. Times.width of 50 mm. Times.length of 150mm was cut out, and the length L1 of the test piece was measured by a vernier caliper. Thereafter, the test piece was subjected to a heating test by an electric furnace. Specifically, the temperature was raised at a rate of about 200 ℃/hr, and the furnace was kept at 1600 ℃ for 3 hours, and the electric furnace was powered off and naturally cooled in the furnace. The length L2 of the test piece after the heating test was measured by the formula: { (L1-L2)/L1 }. Times.100 to calculate the heat shrinkage (%) (the decimal point of the calculated value was rounded off at the 2 nd position).

(4) Shape retention after heating

It was confirmed whether or not the obtained molded article could be transported by hand (handling operation). Further, the amount of scattering of alumina fibers and particles was evaluated by touch and visual observation during the treatment operation. The evaluation criteria are as follows.

< evaluation criterion >

And (2) the following steps: can be handled with less scattering of alumina fiber and particles.

Delta: handling operation is possible, but alumina fibers and particles are scattered much.

X: cannot be disposed of and (3) operating.

(5) Softness (touch)

The molded article was evaluated by the feel of the obtained molded article by hand touch. The evaluation criteria are as follows.

< evaluation criterion >

And (2) the following steps: soft and resilient.

Delta: soft but not resilient.

X: hard.

The evaluation results are summarized in table 1.

TABLE 1

Industrial applicability

The molded article of the present invention can be used as a heat-resistant material and a heat-insulating material for various applications. For example, the material can be suitably used as a furnace material. Specifically, the heat treatment agent can be suitably used as a furnace material for an industrial furnace such as a firing furnace for electronic parts, a cremation furnace, a physicochemical furnace, and the like.

Claims

1. A shaped body, comprising:

alumina fiber containing alumina;

an inorganic binder; and

the surfactant is used as a surfactant in the preparation of the water-soluble polymer,

the content of the alumina is 70 mass% or more.

2. The shaped body according to claim 1, having a density of 80kg/m ³ 200kg/m above ³ The following is given.

3. The molded article according to claim 1 or 2, which has a 30% compression recovery of 85% or more.

4. The molded article according to any one of claims 1 to 3, which has a shrinkage of 3% or less at 1600 ℃.

5. The shaped body according to any one of claims 1 to 4, comprising an organic binder.

6. The molded article according to any one of claims 1 to 5, wherein the content of the inorganic binder is 5 mass% or less.

7. The molded article according to any one of claims 1 to 6, wherein the content of the inorganic binder is 1 mass% or more.

8. The shaped body according to any one of claims 1 to 7, wherein the surfactant comprises a cationic surfactant.

9. The shaped body according to any one of claims 1 to 8, which is substantially free of refractory ceramic fibers.

10. The molded article according to any one of claims 1 to 9, which comprises a polymer coagulant.

11. The molded article according to claim 10, wherein the polymer-based coagulant comprises a first polymer coagulant and a second polymer coagulant.

12. The molded article according to any one of claims 1 to 11, comprising alumina particles containing alumina, wherein the alumina fibers are contained in a proportion of 30 parts by mass or more and 70 parts by mass or less, the alumina particles are contained in a proportion of 30 parts by mass or more and 70 parts by mass or less, and the surfactant is contained in a proportion of 0.1 parts by mass or more and 10 parts by mass or less.

13. The molded article according to any one of claims 1 to 10, which contains substantially no alumina particles containing alumina, wherein the alumina fiber is contained in a proportion of 80 parts by mass or more and 120 parts by mass or less, the alumina particles are contained in an amount of 5 parts by mass or less, and the surfactant is contained in an amount of 0.1 parts by mass or more and 10 parts by mass or less.