TWI793765B - Inorganic formed article - Google Patents

Abstract

The objective of this invention is to provide an inorganic formed article that is hardly deformed by thermal at high temperatures.

The solution to the above-mentioned objective is an inorganic formed article containing: alumina fibers containing alumina at a content of more than 60% by mass, alumina particles, and an inorganic binder; also, the inorganic formed article is substantially free of refractory ceramic fibers whereby the amount of thermal creep is reduced.

Description

Inorganic shaped body

The present invention relates to an inorganic shaped body.

Conventionally, in order to heat-treat electronic components and electrode materials for batteries, etc., firing was performed in an industrial furnace. Furnace materials (insulation materials) installed inside industrial furnaces are required to have low heat capacity and thermal conductivity. By using such a furnace material, the thermal energy during heating is efficiently utilized, and the intermittent time is shortened to improve production efficiency.

In this regard, Patent Document 1 describes an inorganic molded body, which contains alumina fibers, alumina particles, and an inorganic binder, and has a ventilation resistance measured by ASTM C522 of 6×10 ⁵ Pa‧S/ m ² or less, with a bulk density of 100 to 200kg/m ³ , when this inorganic shaped body is used as a furnace material, its heat capacity and thermal conductivity are very low, it has sufficient strength, and it reduces the erosion caused by alkaline gas, and can inhibit Surface peeling or cracking.

[Prior Art Literature]

[Patent Document]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2010-155733

On the other hand, among industrial furnaces, there are furnace materials that require high temperature firing and require less deformation during heating. In this regard, conventional furnace materials include not only crystalline alumina fibers and alumina particles, but also refractory ceramic fibers that are amorphous alumina silica fibers mainly for the purpose of cost reduction.

However, the inventors of the present invention independently researched and found that the latent variable at high temperature of the furnace material containing refractory ceramic fiber is relatively large. When carrying heavy objects, the furnace material is easily damaged and the exchange frequency is easily increased. In addition, when the heating wire is buried in the furnace material and used as a flat panel heater, since the amount of thermal deformation is large, it is easy to impose a load on the heating wire.

The present invention was developed in view of the above problems, and one of its objects is to provide an inorganic molded body that is not easily thermally deformed at high temperatures.

[1] An inorganic molded article according to an embodiment of the present invention to solve the above-mentioned problems includes: alumina fibers having an alumina content of more than 60% by mass, alumina particles, and an inorganic binder, and the inorganic molded article The system reduces the thermal latent variable by substantially not containing refractory ceramic fibers. According to the present invention, it is possible to provide an inorganic molded body that is not easily thermally deformed at high temperatures.

[2] Also, in the above [1], the above-mentioned inorganic shaped body is placed in the center of the longitudinal direction of a flat plate-shaped test body with a length of 150 mm, a width of 45 mm, and a thickness of 7 mm. 10 g of a rectangular parallelepiped hammer with a length of 30 mm and a width of 45 mm is placed. And the aforementioned thermal latent variable measured in the thermal latent change test at 1400°C for 3 hours can satisfy the following (a) or (b): (a) The bulk density of the aforementioned inorganic molded body and the aforementioned test body is less than 300kg /m ³ , and the aforementioned thermal latent variable is 9.0 mm or less; (b) the bulk density of the aforementioned inorganic shaped body and the aforementioned test body is 300 kg/m ³ or higher, and the aforementioned thermal latent variable is 3.0 mm or less.

[3] Also, in the above [1] or [2], the above-mentioned inorganic forming system places a rectangular parallelepiped hammer with a length of 30 mm and a width of 45 mm in the longitudinal center of a flat plate-shaped test body with a length of 150 mm, a width of 45 mm, and a thickness of 7 mm. The thermal latent variable/bulk density ratio obtained by dividing the aforementioned thermal latent variable measured in the thermal latent test at 1400°C for 3 hours by the bulk density of the aforementioned test body can satisfy the following (c) or (d) ): (c) The bulk density of the aforementioned inorganic shaped body and the aforementioned test body is less than 300 kg/m ³ , and the aforementioned thermal latent variable/bulk density ratio is 0.0450 or less; (d) The volume of the aforementioned inorganic shaped body and the aforementioned test body The density is 300 kg/m ³ or more, and the aforementioned thermal latent variable/volume density ratio is 0.0080 or less.

[4] Also, in any one of the aforementioned [1] to [3], the aforementioned inorganic molding system is based on a flat plate-shaped test object with a length of 150 mm, a width of 50 mm, and a thickness of 25 mm that has not been heated at a temperature above 200°C. The maximum load measured in the bending strength test in which the 3-point bending strength testing machine applies the load at a speed of 10mm/min to the test head, the unheated bending strength is obtained from the following formula, and the obtained unheated bending strength is divided by the above test The unheated flexural strength/bulk density ratio obtained by the bulk density of the body may be 0.0031 or more.

Formula: Unheated bending strength (MPa)={3×maximum load (N)×distance between lower fulcrums (mm)}/{2×width of test body (mm)×(thickness of test body (mm)) ² }

[5] In any one of [1] to [4] above, the content of the refractory ceramic fiber in the inorganic shaped body may be 0.1 parts by mass or less with respect to 100 parts by mass of the inorganic shaped body. [6] In any one of the above [1] to [5], in the above-mentioned inorganic shaped body, the average particle diameter of the above-mentioned alumina particles may be 0.5 μm or more and 100 μm or less. [7] Also, in any one of the aforementioned [1] to [6], the bulk density of the aforementioned inorganic shaped body may be 100 kg/m ³ or more and 1000 kg/m ³ or less. [8] Also, in any one of the aforementioned [1] to [7], the aforementioned inorganic shaped body may further include a heating wire.

According to the present invention, it is possible to provide an inorganic molded body that is not easily thermally deformed at high temperatures.

FIG. 1 is an explanatory view showing an example of the results of evaluating the physical properties of an inorganic molded body in one embodiment of the present invention.

Fig. 2 is an explanatory view showing another example of the results of evaluating the physical properties of an inorganic molded body in one embodiment of the present invention.

Hereinafter, an inorganic molded article (hereinafter referred to as "this molded article") according to one embodiment of the present invention will be described. In addition, the present invention is not limited to this embodiment.

The inorganic shaped body of the present shaped body includes: alumina fibers, alumina particles, and an inorganic binder with an alumina content of more than 60% by mass, and the inorganic shaped body reduces heat by substantially not containing refractory ceramic fibers. latent variable.

Alumina fibers are metal oxide fibers containing alumina as a main component. The alumina content exceeds 60% by mass in the alumina-based fibers contained in the molded article. The alumina content of the alumina fiber is not particularly limited as long as it exceeds 60% by mass, for example, it may be 61% by mass or more, 65% by mass or more, or 70% by mass or more.

Also, when the alumina content of the alumina fiber is 70% by mass or more, the alumina content is preferably 72% by mass or more, more preferably 75% by mass or more, and still more preferably 80% by mass or more. More than 85% by mass is particularly preferred.

Furthermore, when the alumina content of the alumina fiber is 85% by mass or more, the alumina content is preferably 90% by mass or more, more preferably 93% by mass or more, and most preferably 95% by mass or more.

The larger the alumina content of the alumina fiber, the lower the thermal latent variable of the molded body including the alumina fiber tends to be. The upper limit of the alumina content of the alumina fibers is not particularly limited, but the alumina content may be, for example, 100% by mass or less, 99% by mass or less, 98% by mass or less, or 97% by mass. Mass % or less may be 96 mass % or less.

The alumina content of the alumina fiber can be specified by combining any one of the above-mentioned lower limit values and any one of the above-mentioned upper limit values arbitrarily. The present molded article may contain two or more types of alumina fibers whose alumina content differs from each other, or may contain only one type of alumina fibers whose alumina content is a specific value.

The alumina fiber may further contain components other than alumina. When the alumina fiber contains components (other components) other than alumina, the other components may be selected from the group consisting of silicon dioxide, zirconia, calcium oxide, iron oxide, sodium oxide (sodia), and magnesium oxide, for example. More than one of these groups, preferably silicon dioxide.

When the alumina fiber contains silica, the content relative to other components in the alumina fiber (when the alumina fiber contains 2 or more other components, it is the total content of the 2 or more other components) 100 parts by mass, the silicon dioxide content can be, for example, more than 60 parts by mass (more than 60 parts by mass and less than 100 parts by mass), preferably more than 70 parts by mass, more preferably more than 80 parts by mass, and more than 90 parts by mass More preferably, more than 95 parts by mass is particularly preferred.

Specifically, for example, the alumina content of the alumina fiber is 80% by mass (that is, the content of other components is 20% by mass), and the content of silica is 90 parts by mass relative to 100 parts by mass of other components. In the above case, the silica content in the alumina fiber is not less than 18 parts by mass and not more than 20 parts by mass.

The average length of the alumina fiber is not particularly limited, for example, preferably 100 μm to 100000 μm, more preferably 1000 μm to 80000 μm, particularly preferably 3000 μm to 50000 μm.

The average fiber diameter of the alumina fiber is not particularly limited, for example, it is preferably from 1 μm to 20 μm, more preferably from 2 μm to 10 μm, and particularly preferably from 3 μm to 7 μm. The aspect ratio (aspect ratio) of the alumina fiber is not particularly limited, but is preferably 25 or more, for example.

Alumina particles may be composed of sintered alumina, but are preferably composed of highly crystalline α-alumina (fused alumina). The average particle size of the alumina particles is not particularly limited, for example, preferably from 0.5 μm to 100 μm, more preferably from 0.5 μm to 50 μm, still more preferably from 0.5 μm to 15 μm, and from 2.0 μm to 10 μm Excellent.

The smaller the average particle diameter of the alumina particles, the higher the mechanical strength of the molded body containing the alumina particles tends to be. In addition, the average particle size of alumina particles was measured by laser diffraction Particle size distribution measuring device to measure.

The inorganic binder is not particularly limited as long as it does not impair the effect of the present invention. For example, it is preferably selected from colloidal silicon dioxide (for example, selected from anionic colloidal silicon dioxide and cationic colloidal silicon dioxide). One or more of the group consisting of silicon), more than one of the group consisting of fume silica, zirconia sol, titania sol, alumina sol, and bentonite, especially colloidal silica.

The molded body may further include an inorganic fixing material. The inorganic fixing material is not particularly limited as long as it does not impair the effects of the present invention. For example, it may be one or more selected from the group consisting of aluminum sulfate, alumina sol, and ammonia water, with aluminum sulfate being preferred.

The molded body may further include an organic binder. The organic binder is not particularly limited as long as it does not impair the effects of the present invention. For example, it is preferably at least one selected from the group consisting of polymer coagulants and starch. Also, when the molded body contains a polymer flocculant, the molded body may further contain starch, or may not contain starch.

The polymer coagulant used as the organic binder is not particularly limited as long as it does not impair the effect of the present invention. For example, it is preferably selected from polyacrylamide-based polymers, amide-based polymers, polyacrylate-based One or more of the group consisting of polymers and polyacrylate ether polymers, especially polyacrylamide polymers are preferred.

The starch used as the organic binder is not particularly limited as long as it does not impair the effect of the present invention, for example, it can be selected from raw material starch (for example, starch derived from natural raw materials (for example, selected from potato starch, tapioca starch, More than one of the group consisting of maize starch and its hydrolyzate), cationic starch, anionic starch, and amphoteric starch.

The molded body can further contain pulp or appropriate emulsion as organic binder. In the manufacture of this molded body, the type and amount of the organic binder added to the solvent to form the desired size of the rubber plume depends on the amount of charge of the inorganic binder, the nature of the charge, and the alumina particles used. The size etc. should be optimized.

In addition, this molding system contains an organic binder at least at the point of its molding (for example, the point at which the inorganic molding is obtained by drying a wet molding obtained by dehydration molding or papermaking described later). agent is better.

On the other hand, as will be described later, after the molded body is molded, it may be subjected to firing treatment before shipment or use. In the molded body subjected to firing treatment, part or all of the organic binder contained before the firing treatment may disappear.

The bulk density of the molded body is not particularly limited as long as it does not impair the effect of the present invention, for example, it can be from 100kg/ ^m3 to 1000kg/ ^m3 , to 150kg/ ^m3 to 1000kg/ ^m3 More preferably, more than 200kg/ ^m3 and less than 1000kg/ ^m3 , more preferably more than 300kg/ ^m3 and less than 1000kg/ ^m3 .

Here, one of the characteristics of the molded body is that the molded system reduces the thermal latent variable by substantially not including refractory ceramic fibers (RCF).

That is, as mentioned above, the inventors of the present invention conducted their own research and found that the furnace material including RCF has a relatively large latent variable at high temperature. On the other hand, since this molded body does not contain RCF substantially, compared with the conventional furnace material containing RCF, the thermal latent variable is reduced.

RCF is an amorphous alumina silica fiber having an alumina (Al ₂ O ₃ ) content of 60% by mass or less. Specifically, RCF contains 30 to 60 mass % of Al ₂ O ₃ , and 40 to 60 mass % of SiO ₂ . RCF may further include R _n O _m (R is Zr or Cr) of 20% by mass or less. That is, the RCF may contain 0% by mass to 20% by _mass of _RnOm (R is Zr or Cr). The average fiber diameter of RCF is generally 1 μm to 3 μm. RCF is manufactured using the melt fiberization method.

Specifically, the molded body whose thermal latent variable is reduced by substantially not including RCF, for example, in the longitudinal center of a flat plate-shaped test body with a length of 150 mm, a width of 45 mm, and a thickness of 7 mm, when RCF is substantially not included The thermal latent variable measured in the thermal latent change test of placing a rectangular parallelepiped hammer with a length of 30mm and a width of 45mm at the top and keeping it at 1400°C for 3 hours can satisfy the following (a) or (b): (a) This forming The bulk density of the molded body and the test body is less than 300kg/m ³ , and the thermal latent variable is less than 9.0 mm; (b) The bulk density of the molded body and the test body is more than 300 kg/m ³ , and the aforementioned thermal latent variable is Below 3.0mm.

In the above-mentioned thermal creep test, the molded body was processed to produce a test body composed of the molded body of the above-mentioned size and shape, and a load of 10 g was applied to the test body while being kept at 1400°C for 3 hours, and the temperature at this time was measured. The amount of deformation is taken as the thermal latent variable.

When the molded article satisfies the above (a), the bulk density of the molded article and the test article is not particularly limited as long as it is less than 300kg/m ³ (for example, 299kg/m ³ or less), for example, it can be 100kg/m ³ More than and less than 300kg/m ³ , may be more than 130kg/m ³ and less than 300kg/m ³ , may be more than 150kg/m ³ and less than 300kg/m ³ .

Also, the thermal latent variable of the molded body satisfying the above (a) is, for example, preferably 8.0 mm or less, more preferably 7.0 mm or less, still more preferably 6.0 mm or less, and most preferably 5.0 mm or less.

Furthermore, when the thermal latent variable of the molded article satisfying the above (a) is 5.0 mm or less, the thermal latent variable is preferably 4.0 mm or less, more preferably 3.5 mm or less, and particularly 3.0 mm or less. good.

When the molded body satisfies the above (b), the bulk density of the molded body and the test body is not particularly limited as long as it is 300 kg/m ³ or more, for example, it may be 300 kg/m ³ or more and 1000 kg/m ³ or less.

In addition, the thermal latent variable of the molded article satisfying the above (b) is, for example, preferably 2.5 mm or less, particularly preferably 2.0 mm or less.

In addition, the molded body whose thermal latent variable is reduced by substantially not including RCF, for example, in the case of substantially not including RCF, is placed in the longitudinal center of a flat plate-shaped test body with a length of 150 mm, a width of 45 mm, and a thickness of 7 mm. Thermal latent variable/bulk density ratio obtained by dividing the aforementioned thermal latent variable by the bulk density of the test object measured in the thermal latent change test of a rectangular parallelepiped hammer with a length of 30 mm and a width of 45 mm at 1400°C for 3 hours The following (c) or (d) can be satisfied: (c) The bulk density of the molded body and the test body is less than 300kg/m ³ , and the thermal latent variable/bulk density ratio is 0.0450 or less; (d) The bulk density of the molded body and the test body is 300 kg/m ³ or more, and the thermal latent variable/bulk density ratio is 0.0075 or less.

When the molded article satisfies the above (c), the bulk density of the molded article and the test article is not particularly limited as long as it is less than 300kg/m ³ (for example, 299kg/m ³ or less), for example, it can be 100kg/m ³ or more And less than 300kg/m ³ , may be more than 130kg/m ³ and less than 300kg/m ³ , may be more than 150kg/m ³ and less than 300kg/m ³ .

In addition, the thermal latent variable/bulk density ratio of the molded body satisfying the above (c) may be, for example, 0.0400 or less, preferably 0.0350 or less, more preferably 0.0300 or less, still more preferably 0.0250 or less, and 0.0200 or less For the best.

When the molded body satisfies the above (d), the bulk density of the molded body and the test body is not particularly limited as long as it is 300 kg/m ³ or more, for example, it may be 300 kg/m ³ or more and 1000 kg/m ³ or less.

In addition, the thermal latent variable/bulk density ratio of the molded body satisfying the above (d) may be, for example, 0.0075 or less, preferably 0.0070 or less, more preferably 0.0600 or less, still more preferably 0.0500 or less, and 0.0400 or less For the best.

In addition, the molded body whose thermal latent variable is reduced by substantially not containing RCF, for example, in the case of substantially not containing RCF, is based on a length of 150mm, a width of 50mm, and a thickness of 25mm that have not been heated at a temperature above 200°C. The maximum load measured in the bending strength test of the flat plate shape test body using a 3-point bending strength testing machine at a speed of 10mm/min to the test head, is determined by the formula: unheated bending strength (MPa)={3× Maximum load (N)×distance between lower fulcrums (mm)}/{2×width of test body (mm)×(thickness of test body (mm)) ² } to obtain the unheated bending strength, and the obtained unheated The unheated flexural strength/bulk density ratio obtained by dividing the flexural strength by the bulk density of the test body may be 0.0031 or more.

In the above flexural strength test, process the unheated (not heated at a temperature above 200°C) this molded body to make a test body composed of the above size and shape of the molded body, and use 3 points for this test body The bending strength testing machine measures the maximum strength (bursting strength) when the load is applied at a speed of 10 mm/min of the test head, and calculates the unheated bending strength from the above formula.

The unheated bending strength/bulk density ratio of the molded article is preferably, for example, 0.0035 or higher, and particularly preferably 0.0040 or higher.

The molded article substantially not containing RCF is an inorganic molded article, and the inorganic molded system has an RCF content of 0.1 parts by mass or less with respect to 100 parts by mass of the molded article. Relative to 100 parts by mass of this molded body, the content of RCF is, for example, 0.07 parts by mass or less. Best, especially preferably less than 0.05 parts by mass.

The content of the alumina fibers in this molded body is not particularly limited as long as it is within the range that does not impair the effects of the present invention. For example, this molded body may contain 15 parts by mass relative to 100 parts by mass of this molded body. More than 90 parts by mass of alumina fiber, may also contain 20 parts by mass or less than 85 parts by mass of alumina fiber, may also contain 25 parts by mass or less than 80 parts by mass of alumina fiber, may also contain 30 parts by mass More than 75 parts by mass of alumina fiber.

In addition, the molding system may contain, for example, 10 parts by mass or more and 90 parts by mass or less of alumina fibers by mass, or may contain 20 parts by mass or more and 90 parts by mass with respect to a total of 100 parts by mass of the alumina fiber content and the alumina particle content. The alumina fiber of not more than 30 parts by mass and not more than 90 parts by mass may contain alumina fiber of not more than 40 parts by mass and not more than 80 parts by mass.

The content of the alumina particles in this molded body is not particularly limited as long as it is within the range that does not impair the effect of the present invention, but this molded body may contain 5 parts by mass or more based on 100 parts by mass of this molded body. 65 parts by mass or less of alumina particles may contain 10 to 60 parts by mass of alumina particles, or may contain 15 to 55 parts by mass of alumina particles.

When the bulk density of the molded article is less than 300 kg/m ³ , the content of alumina fibers with an alumina content of 72% by mass or less relative to 100 parts by mass of the total content of alumina fibers and alumina particles It may be less than 40 mass %, may be 35 mass % or less, may be 20 mass % or less, and may be 10 mass % or less.

In addition, when the bulk density of the molded body is less than 300 kg/m ³ , the alumina content in the alumina fiber contained in the molded body may be 72% by mass or more, may be 75% by mass or more, or may be More than 80% by mass.

When the bulk density of the molded article is 300 kg/m3 ^or more, the content of alumina fibers with an alumina content of 72% by mass or less may be 100 parts by mass of the total content of alumina fibers and alumina particles. It may be less than 60 mass %, may be 55 mass % or less, may be 50 mass % or less, may be 45 mass % or less, and may be 40 mass % or less.

The content of the inorganic binder in the molded article is not particularly limited as long as it does not impair the effects of the present invention, and is based on 100 parts by mass of the total content of alumina fibers and alumina particles. For example, the molding system preferably contains 1 to 20 parts by mass of inorganic binder, more preferably contains 3 to 17 parts by mass of inorganic binder, and contains 5 to 15 parts by mass. The inorganic binder is especially good.

When the molded article contains an inorganic fixing material, the content of the inorganic fixing material in the molded article is not particularly limited as long as the effect of the present invention is not impaired. The total content of particles is 100 parts by mass. For example, the forming system preferably contains 0.1 to 15 parts by mass of an inorganic fixing material, more preferably 0.1 to 10 parts by mass of an inorganic fixing material. It is especially preferable to contain the inorganic fixing material in an amount of not less than 0.1 parts by mass and not more than 5 parts by mass.

When the molded article contains an organic binder, the content of the organic binder in the molded article is not particularly limited as long as it does not impair the effects of the present invention. The total content of the particles is 100 parts by mass. For example, the forming system preferably contains 0.1 to 15 parts by mass of an organic binder, more preferably contains 0.5 to 10 parts by mass of an organic binder, and Contains more than 1 part by mass and 5 parts by mass An organic binder of less than 100% is particularly preferred.

In order to function as a heat insulating material, this molding system preferably has a sufficiently low thermal conductivity. That is to say, the thermal conductivity of the molded body at 600°C is preferably not more than 0.45 (W/m‧K), more preferably not more than 0.35 (W/m‧K), and preferably not more than 0.25 (W/m‧K). ) The following are particularly preferred.

The present shaped body may contain heating wires. That is, at this time, the molded body includes, for example, heating wires arranged on the surface thereof. The present forming system comprising heating wires is used, for example, as a panel heater. The heating wire is not particularly limited, for example, it is preferably a metal wire that generates heat when energized (for example, nickel-chromium wire or molybdenum disilicide).

This molded body is preferably produced by the following method. In the manufacturing method of this compact, first, the slurry containing the above-mentioned alumina fiber, alumina particle, and an inorganic binder is prepared. At this time, the slurry can be prepared to further include an inorganic fixing material. Also, it can be prepared into a slurry that further contains an organic binder.

The wet volume of the slurry is not particularly limited as long as it does not impair the effect of the present invention, for example, it is preferably 50mL/20g or more and 1000mL/20g or less, more preferably 75mL/20g or more and 950mL/20g or less , preferably 100mL/20g or more and 900mL/20g or less.

Then, a wet shaped body is obtained by subjecting the slurry to dehydration forming or papermaking. Here, the wet molded body can be squeezed as needed (for example, when manufacturing the molded body with a relatively high bulk density).

Thereafter, the molded body was wetted by drying to obtain an inorganic molded body (the present molded body). The shape of the molded body is not particularly limited, for example, a plate shape, sheet shape, or block shape is preferred. In addition, the shape of the molded body can also be formed by selecting a suction mold according to the desired shape. Other shapes such as cylindrical or conical.

In addition, this molded body may be further subjected to a firing treatment. That is, for example, when using the molded body as a heat insulating material or a refractory material, the molded body may be subjected to firing treatment before shipment, before use, or during use.

The method of firing treatment is not particularly limited, for example, it can be performed using a known heating furnace. The firing temperature is not particularly limited as long as it is within the range that does not impair the effect of the present invention, for example, it is preferably 600°C or higher (for example, 600°C or higher and 1600°C or lower). The firing time is not particularly limited as long as the effect of the present invention is not impaired, for example, it is preferably 30 minutes or more (for example, 30 minutes to 60 minutes).

In addition, this molded body may be subjected to hardening treatment. The hardening treatment is, for example, a treatment of impregnating the molded body with a hardening treatment solution containing an inorganic binder (for example, one or more selected from the group consisting of colloidal silica and alumina sol) and drying it. Hardening treatment can effectively increase the hardness of the molded body after drying.

The hardening treatment liquid system, for example, in addition to the inorganic binder, may also include an organic tackifier and an inorganic powder selected from the group used to control the viscosity (for example, one selected from the group consisting of glass powder, alumina powder and wollastonite powder) More than one of the groups formed by the above). The method of impregnating the molded body with the hardening treatment liquid is not particularly limited. For example, it is preferable to use at least one selected from the group consisting of brush coating, spray coating, and dipping.

In addition, this molded body can be given a surface coating treatment. That is, for example, by applying a coating agent containing ZrO ₂ , SiO ₂ and SiC ₄ , or a coating agent containing Al ₂ O ₃ and SiO ₂ to the surface of the molded body, the surface properties of the molded body can be effectively improved . Specifically, for example, when the molded body is used in a furnace, the corrosion resistance to scale (such as iron oxide) in the furnace can be effectively improved by applying surface coating treatment to the molded body, and/or Wind speed resistance to hot air in the furnace.

Also, this molded body can be subjected to an adhesive treatment. That is, for example, when bonding a plurality of molded bodies to each other, or when bonding this molded body to another molded body, by using an adhesive containing Al ₂ O ₃ and SiO ₂ , or an adhesive containing Fe and SiO ₂ Coating on the adhesive surface of this molded body can effectively improve its adhesive force.

Also, when manufacturing the molded body including the heating wire (for example, the molded body belonging to the panel heater), for example, by placing the heater wire in the molding die in advance during suction molding, the molded body can be wetted. The heating wire can be included in the part, or the molded body can be cut and processed to bury the heating wire in the cut part, and a cover can be further provided. According to the former method, the holding force of the heating wire is high, and it is not easy to produce contact with the object to be heated. According to the latter method, it is easy to manufacture the molded body including the heating wire, and the thermal efficiency is high. In addition, in the latter method, the workability is improved by applying the above-mentioned hardening treatment to the cut surface of the molded body before embedding the heating wire. Also, since the molded body has high strength, machining accuracy is improved during cutting.

Next, specific examples of this embodiment will be described.

[Example]

[Raw material] Inorganic fibers used: (I) Alumina fibers with an alumina content of 95% by mass (manufactured by Denka Co., Ltd., "B95N5", with a silica content of 5% by mass, α-oxidized Aluminum content of 50% by mass to 59% by mass, average fiber diameter of 2 μm to 4 μm), (II) alumina fiber with an alumina content of 80% by mass (manufactured by Denka Co., Ltd., “B80”, silica content of 20% by mass %, the content of mullite (mullite) in alumina is 50 mass % to 70 mass %, the average fiber diameter is 3 μm to 5 μm), (III) the alumina content is 72 Alumina fibers (manufactured by Mitsubishi Chemical Co., Ltd., "MAFTEC") by mass %, with a silica content of 28 mass %, a mullite content of 0 mass % to 59 mass % in alumina, and an average fiber diameter of 5 μm to 7 μm), and, (V)RCF (manufactured by NICHIAS Co., Ltd., “FINEFLEX 1300”, alumina content 49% by mass, silica content 51% by mass, average fiber diameter 2 μm to 3 μm).

Alumina particles (manufactured by Nippon Light Metal Co., Ltd., "SA31", average particle diameter: 5 µm, Al ₂ O ₃ : 99.4% or more) were used as the inorganic particles.

As the inorganic binder, colloidal silicon dioxide (manufactured by Nippon Chemical Industry Co., Ltd., "Silicadol 30", a suspension of 30% by mass of solid matter, an average particle diameter of solid matter of 15 nm, and pH 10.0) and alumina sol ( Manufactured by Nissan Chemical Industry Co., Ltd., "Alumina Sol 520", 20% by mass solid suspension, pH 4.0).

Aluminum sulfate (manufactured by Asada Chemical Industry Co., Ltd., "liquid aluminum sulfate", alumina 8.0 to 8.2%, pH 3.0 or higher) was used as the inorganic fixing material. The organic binder is polyacrylamide (manufactured by Arakawa Chemical Industry Co., Ltd., "POLYSTRON 705", cationic, non-volatile content 10%, pH 2.5 to 3.5, viscosity 300 to 1000mPa‧s) ), and starch (manufactured by Nichiden Chemical Co., Ltd., "PETROSIZE J").

[Inorganic molded body] With the formula shown in Figure 1 and Figure 2, add inorganic fibers, inorganic particles, inorganic binders, inorganic fixing materials, and organic binders to water, then add water so that the concentration of the slurry becomes 2% by mass and Stir to make a slurry.

The slurry obtained in the above manner is poured into a forming mold with a net at the bottom, and dehydrated by a suction dehydration forming method in which a solvent is sucked to obtain a flat plate shape. shaped wet form. Furthermore, in Examples 8 to 14 and Comparative Example 3, the wet molded body obtained in the above manner was pressed so that the bulk density of the finally obtained inorganic matter molded body fell within a desired range. On the other hand, in Examples 1 to 7 and Comparative Examples 1 and 2, the wet molded body was not pressed. Then, the wet molded body obtained in each example was dried at 110° C. for 36 hours in a dryer to obtain a plate-shaped inorganic molded body with a thickness of 25 mm.

[Bulk Density] The bulk density of the inorganic molded body obtained in each example was calculated by dimensional measurement (length, width, thickness) with a caliper and weight measurement with an electronic balance.

[Unheated flexural strength] The unheated flexural strength of the inorganic molded body obtained in each example was measured as follows. A universal strength testing machine (manufactured by Shimadzu Corporation, "AUTOGRAPH") was applied to a flat-shaped test piece with a length of 150 mm, a width of 50 mm, and a thickness of 25 mm composed of an inorganic molded body at a speed of 10 mm/min. As for the load, the maximum load (breaking load) was measured.

Then, calculate the unheated flexural strength of the inorganic shaped body according to the following formula: unheated flexural strength (MPa)={3×maximum load (N)×distance between lower fulcrums (mm)}/{2×width of test body ( mm)×(thickness of test body (mm)) ² }.

[Heating shrinkage rate] The flat-shaped test piece with a length of 150mm, a width of 50mm, and a thickness of 25mm obtained in each example and composed of an inorganic molded body was heated at 1400°C for 24 hours, or at 1600°C for 24 hours, according to the following formula Calculate the heat shrinkage rate (%): {length of test body before heating (mm)-length of test body after heating (mm)}/length of test body before heating (mm)×100. The measurement of the length of the test body is carried out using a caliper.

[Thermal latent variable] The thermal latent variable of the inorganic molded body obtained in each example was measured by the following thermal latent test. That is, first, a pair of supporting members (30 mm in height) arranged at a distance of 120 mm in the longitudinal direction of the test body supports the length of a flat plate-shaped test body consisting of an inorganic molded body with a length of 150 mm, a width of 45 mm, and a thickness of 7 mm. both ends of the direction.

Then, in the central portion of the test body in the longitudinal direction, place a hammer body having a rectangular parallelepiped shape with a length of 30 mm and a width of 45 mm and a weight of 10 g or 30 g. Also, the test body was not bent at all because the hammer was placed at room temperature.

Then, the test body on which the weight was placed was heated and kept at a temperature of 1400°C, 1500°C or 1600°C for 3 hours or 24 hours. By the above-mentioned heating, the test body is deflected, and the central part in the longitudinal direction is displaced downward. Next, the displacement amount (deflection amount) due to the above-mentioned heating was measured as a thermal latent variable (mm).

[Results] In Fig. 1, for inorganic shaped bodies with a bulk density of 150kg/ ^m3 to 257kg/ ^m3 (Examples 1 to 7 and Comparative Examples 1 and 2, wherein the bulk densities of Examples 1 to 7 are 184kg respectively /m ³ , 203kg/m ³ , 257kg/m ³ , 150kg/m ³ , 183kg/m ³ , 163kg/m ³ , 191kg/m ³ ) show the components (inorganic fiber, inorganic particle, inorganic binder, inorganic Fixing material, and organic binder) content, and the measurement results of physical properties are shown in Figure 2 for inorganic molded bodies with a bulk density of 319kg/m ³ to 380kg/m ³ (embodiments 8 to 14 and comparative example 3) The content and physical properties of each component (inorganic fiber, inorganic particle, inorganic binder, inorganic fixing material, and organic binder) are measured. In addition, in FIG. 1 and FIG. 2, the mass part of an inorganic binder shows the solid content conversion value. In addition, in FIG. 1 and FIG. 2, the symbol "-" shows that the measurement of the physical property was not performed.

As shown in Figure 1, when a load of 10 g is applied at 1400°C for 3 hours, the thermal latent variable B of the inorganic molded articles of Examples 1 to 5 is 2.2 mm to 2.7 mm, compared with the inorganic molded articles of Comparative Examples 1 and 2 The thermal latent variable B (9.2mm to 13.1mm) of the body is significantly smaller.

In addition, the ratio of thermal latent variable B/bulk density obtained by dividing the thermal latent variable B of the inorganic molded body of Examples 1 to 5 by the bulk density is 0.0086 to 0.0173, compared with the thermal latent variable B of Comparative Examples 1 and 2 The /bulk density ratio (0.0460 to 0.0649) is significantly smaller.

Also, when a load of 10 g was applied at 1600°C for 3 hours, the thermal latent variable D of the inorganic molded articles of Examples 1 to 3, and 5 was 12.5 mm to 29.5 mm, which was compared with the thermal latent variable of the inorganic molded article of Comparative Example 1. The variant D (36.0mm) is significantly smaller.

In addition, the thermal latent variable D/volume density ratio of the inorganic shaped body of Examples 1 to 3 and 5 is 0.0537 to 0.1612, compared with the thermal latent variable D/bulk density ratio of the inorganic shaped body of Comparative Example 1 (0.1800), Significantly smaller.

In addition, the unheated flexural strength/bulk density ratio of the inorganic molded articles of Examples 1 to 3 was 0.0042 to 0.0061, compared with the unheated flexural strength/bulk density ratio of the inorganic molded articles of Comparative Examples 1 and 2 (0.0025 to 0.0030 ) is significantly larger.

As shown in Figure 2, the thermal latent variable B of the inorganic shaped body of Examples 8 to 12 is 0.9 mm to 1.4 mm, which is significantly smaller than the thermal latent variable B (3.1 mm) of the inorganic shaped body of Comparative Example 3. And it is smaller than the thermal latent variable B (2.2 mm to 2.7 mm) of the inorganic shaped body of Examples 1 to 5.

In addition, the thermal latent variable B/volume density ratio of the inorganic shaped body of Examples 8 to 14 is 0.0028 to 0.0039, compared with the thermal latent variable B/bulk density ratio of the inorganic shaped body of Comparative Example 3 (0.0082) and Example The thermal latent variable B/volume density ratio (0.0086 to 0.0173) of the inorganic shaped bodies of 1 to 5 is significantly smaller.

In addition, the thermal latent variable D of the inorganic shaped body of Examples 8 to 14 is 7.4 mm to 18.5 mm, which is significantly smaller than the thermal latent variable D (21.0 mm) of the inorganic shaped body of Comparative Example 3.

In addition, the thermal latent variable D/volume density ratio of the inorganic shaped body of Examples 8 to 10 and 12 is 0.0219 to 0.0486, compared with the thermal latent variable D/bulk density ratio of the inorganic shaped body of Comparative Example 3 (0.0553) and The thermal latent variable D/bulk density ratio (0.0537 to 0.1612) of the inorganic shaped bodies of Examples 1 to 3 and 5 is significantly smaller.

Also, when a load of 30 g was applied at 1400°C for 3 hours, the thermal latent variable A of the inorganic molded articles of Examples 10, 12, and 14 was 2.0 mm to 2.6 mm. Variant A (18.0mm) is significantly smaller.

In addition, the thermal latent variable A/volume density ratio of the inorganic shaped body of Examples 10, 12, and 14 is 0.0054 to 0.0070, which is significantly higher than the thermal latent variable A/bulk density ratio (0.0474) of the inorganic shaped body of Comparative Example 3. smaller.

Also, when a load of 10 g was applied at 1500°C for 3 hours, the thermal latent variable C of the inorganic molded articles of Examples 10, 12, and 14 was 3.7 mm to 3.9 mm. Variant C (16.5mm) is significantly smaller.

Also, the thermal latent variable C/volume density ratio of the inorganic shaped articles of Examples 10, 12, and 14 is 0.0100 to 0.0108, which is significantly higher than the thermal latent variable C/bulk density ratio (0.0434) of the inorganic shaped article of Comparative Example 3. smaller.

Also, when a load of 10 g was applied at 1400°C for 24 hours, the thermal latent variable E of the inorganic molded articles of Examples 10, 12, and 14 was 2.8 mm to 3.5 mm. The variable E (13.5mm) is significantly smaller.

Also, the thermal latent variable E/volume density ratio of the inorganic shaped bodies of Examples 10, 12, and 14 is 0.0076 to 0.0097, which is significantly higher than the thermal latent variable E/bulk density ratio (0.0355) of the inorganic shaped bodies of Comparative Example 3. smaller.

Also, when a load of 10 g was applied at 1600°C for 24 hours, the thermal latent variable F of the inorganic molded articles of Examples 10, 12, and 14 was 20.5 mm to 30.5 mm. The variable F (37.0mm) is significantly smaller.

In addition, the thermal latent variable F/volume density ratio of the inorganic shaped body of Examples 10, 12, and 14 is 0.0554 to 0.0824, which is significantly higher than the thermal latent variable F/bulk density ratio (0.0974) of the inorganic shaped body of Comparative Example 3. smaller.

In addition, the unheated flexural strength/bulk density ratio of the inorganic molded articles of Examples 8 to 10 and 12 is 0.0057 to 0.0071, which is significantly higher than the unheated flexural strength/bulk density ratio (0.0019) of the inorganic molded article of Comparative Example 3. bigger.

In addition, when heated at 1400° C. for 24 hours, the heat shrinkage rate of the inorganic molded body of Examples 8 to 12 was 0.3%, which was significantly smaller than that of the inorganic molded body of Comparative Example 3 (0.9%).

Claims (7)

An inorganic shaped body comprising: alumina fibers with an alumina content of more than 60% by mass, alumina particles with an average particle size of 2.0 μm to 10 μm, and an inorganic binder, and the inorganic shaped system is relatively 100 parts by mass of the total content of the fiber content and the content of the aforementioned alumina particles, including 10 parts by mass to 90 parts by mass of the aforementioned alumina fiber and 1 part by mass to 20 parts by mass of the aforementioned inorganic binder, substantially no Contains refractory ceramic fiber, with a bulk density of 203kg/ ^m3 or more, and place a 30mm in length, 45mm in width in the central part of the longitudinal direction of a flat plate with a bulk density of 203kg/m3 or ^more in length 150mm, width 45mm, and thickness 7mm. The thermal latent variable measured in the thermal latent change test of holding 10 g of a rectangular parallelepiped hammer at 1400° C. for 3 hours is 3.0 mm or less. The inorganic shaped body according to claim 1, wherein the thermal latent variable satisfies the following (a) or (b): (a) the bulk density of the aforementioned inorganic shaped body and the aforementioned test body is less than 300 kg/m ³ , And the aforementioned thermal latent variable is 3.0 mm or less; (b) the bulk density of the aforementioned inorganic shaped body and the aforementioned test body is 300 kg/m ³ or more, and the aforementioned thermal latent variable is 3.0 mm or less. The inorganic shaped body according to claim 1 or 2, wherein the thermal latent variable/bulk density ratio obtained by dividing the thermal latent variable by the bulk density of the test body satisfies the following (c) or (d): (c ) The bulk density of the aforementioned inorganic shaped body and the aforementioned test body is less than 300 kg/m ³ , and the aforementioned thermal latent variable/bulk density ratio is 0.0450 or less; (d) The aforementioned inorganic matter shaped body and the aforementioned test body have a bulk density of 300 kg/m 3 m ³ or more, and the aforementioned thermal latent variable/bulk density ratio is 0.0080 or less. The inorganic molded body according to Claim 1 or 2, wherein a 3-point bending strength tester is used to test the head of a flat plate-shaped test body with a length of 150 mm, a width of 50 mm, and a thickness of 25 mm that has not been heated at a temperature above 200°C. The maximum load measured in the flexural strength test with a speed of 10mm/min. The unheated flexural strength is obtained from the following formula, and the unheated flexural strength obtained by dividing the obtained unheated flexural strength by the bulk density of the above-mentioned test body is obtained. Bending strength/bulk density ratio is above 0.0031, formula: unheated bending strength (MPa)={3×maximum load (N)×distance between lower fulcrums (mm)}/{2×width of test body (mm)×( The thickness of the test body (mm)) ² }. The inorganic shaped body according to claim 1 or 2, wherein the content of the refractory ceramic fiber is 0.1 parts by mass or less with respect to 100 parts by mass of the shaped inorganic body. The inorganic shaped body according to claim 1 or 2, wherein the bulk density is 203 kg/m ³ or more and 1000 kg/m ^{3 or} less. The inorganic molded body according to claim 1 or 2 further includes a heating wire.

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