Heat-resistant plate members and structures

Abstract

A heat-resistant plate member according to the present invention is a paper-making molded body including an inorganic fiber filler containing an alumina fiber and an inorganic porous filler containing CaO∙6Al2O3, and is configured such that the bulk density of the heat-resistant plate member, which has been subjected to a firing treatment at 1,400ºC for 60 minutes, is 0.10 g / cm3 to 0.30 g / cm3 (exclusive of 0.30).

Description

[Technical Field]

[0001] The present invention relates to a heat-resistant plate member and a structure. [Background technology]

[0002] Various developments have been made in the field of heat-resistant plate members. One known example of this type of technology is the technology described in Patent Document 1. Patent Document 1 describes an inorganic fiber molded body, as a high-temperature fire-resistant insulating material, which is obtained by vacuum molding a slurry containing alumina fiber, alumina powder, silica sol, and starch (Table 1 of Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-194863 Summary of the Invention [Problem to be solved by the invention]

[0004] However, as a result of investigations by the present inventors, it has been found that the inorganic fiber molded article described in Patent Document 1 has room for improvement in terms of weight reduction and heat insulation properties. [Means for solving the problem]

[0005] The present inventors have investigated the use of alumina fibers, which have a moderately large specific gravity, as an inorganic fiber filler for heat insulating members produced by a papermaking method, from the viewpoint of the mechanical strength of the member. However, if the content of alumina fibers is increased, the thermal conductivity at high temperatures cannot be suppressed, and there is a risk that the heat insulating properties will decrease. By replacing some of the alumina fibers with alumina powder, it became possible to keep the thermal conductivity low at high temperatures, but on the other hand, there was a risk that the bulk density would increase and the material would become heavier.

[0006] The inventors have investigated this trade-off between heat insulation and weight reduction and have found that by using an inorganic porous filler containing CaO·6Al2O3 in combination with alumina fibers, it is possible to reduce weight while keeping thermal conductivity low at high temperatures, thereby improving weight reduction and heat insulation, and have completed the present invention.

[0007] According to one aspect of the present invention, the following heat-resistant plate member and structure are provided.

[0008] 1. A heat-resistant plate member made of a paper-molded article containing an inorganic fiber filler and an inorganic porous filler, the inorganic fiber filler includes alumina fibers, the inorganic porous filler contains CaO 6Al2O3, After being fired at 1400°C for 60 minutes, the heat-resistant plate member has a bulk density of 0.10 g / cm 3 More than 0.30g / cm 3 A heat-resistant plate member having a thickness of less than 1 / 2 mm. 2. The heat-resistant plate member according to 1., The heat-resistant plate member has a content of the alumina fibers of 10 parts by mass or more and 85 parts by mass or less per 100 parts by mass of the total of the inorganic fiber filler, the inorganic porous filler, and the inorganic binder. 3. The heat-resistant plate member according to 1. or 2., The alumina fibers have a true specific gravity of 3.0 or more and 3.8 or less, and contain Al2O3 and SiO2. 4. A heat-resistant plate member according to any one of 1. to 3., The heat-resistant plate member, wherein the alumina fibers have a mullite content of 1% by mass or more and 80% by mass or less. 5. A heat-resistant plate member according to any one of 1. to 4., A heat-resistant plate member, wherein the content of shots of 50 μm or more in length in the alumina fibers, measured in accordance with ISO10635, is 0.1% or more and 10% or less. 6. A heat-resistant plate member according to any one of 1. to 5., The heat-resistant plate member has a content of the inorganic porous filler of 1 part by mass or more and 70 parts by mass or less per 100 parts by mass of the total of the inorganic fiber filler, the inorganic porous filler, and the inorganic binder. 7. A heat-resistant plate member according to any one of 1. to 6., A heat-resistant plate member comprising a binder selected from at least one of an inorganic binder and an organic binder. 8. The heat-resistant plate member according to 7., The heat-resistant plate member, wherein the inorganic binder comprises one or more selected from the group consisting of colloidal silica and alumina sol. 9. The heat-resistant plate member according to 7., The heat-resistant plate member, wherein the organic binder comprises one or more selected from the group consisting of polyvinyl alcohol, starch, polyethylene glycol, a (meth)acrylic acid ester copolymer, and polyoxyethylene alkyl ether. 10. A structure comprising the heat-resistant plate member described in any one of 1. to 9. [Effects of the Invention]

[0009] According to the present invention, a heat-resistant plate member that is lightweight and has excellent heat insulating properties, and a structure using the same are provided. DETAILED DESCRIPTION OF THE INVENTION

[0010] The heat-resistant plate member of this embodiment will be outlined below.

[0011] The heat-resistant plate member of this embodiment is a molded article containing an inorganic fiber filler containing alumina fiber and an inorganic porous filler containing CaO·6Al2O3 (hereinafter referred to as CA6), and after being fired at 1400°C for 60 minutes, the bulk density of the heat-resistant plate member is 0.10 g / cm 3 More than 0.30g / cm 3 It is configured to be less than.

[0012] According to the findings of the present inventors, it has been found that by using an inorganic porous filler containing CA6 in combination with alumina fibers, it is possible to reduce the weight while keeping the thermal conductivity at high temperatures low.

[0013] Although the detailed mechanism is unclear, it is thought that inorganic porous fillers containing CA6 can appropriately control the pores to reduce the bulk density of the entire heat-resistant plate component, thereby preventing the formation of thermal conduction paths through the alumina fibers.

[0014] Furthermore, by using alumina fibers with a moderately large true specific gravity of 3.0 or more and 3.8 or less, it is possible to increase the mechanical strength of the heat-resistant plate member.

[0015] The structure of this embodiment includes a heat-resistant plate member. The use of the heat-resistant plate member makes it possible to realize a lightweight structure that exhibits excellent heat insulation properties in high-temperature environments of 1000°C or higher, and that can suppress an increase in thermal conductivity at high temperatures such as 1000°C or 1400°C.

[0016] The heat-resistant plate member can be used for any component that requires heat resistance, but is suitable for use in high-temperature environments that require heat resistance of 1400°C or higher, for example. The heat-resistant plate member can be used as a high-temperature fire-resistant insulating material in a wide range of fields, including steel, metals, ceramics, and automobiles.

[0017] The components of the heat-resistant plate member will be described in detail below.

[0018] The heat-resistant plate member contains an inorganic fiber filler. The inorganic fiber filler includes alumina fiber from the viewpoint of thermal conductivity. Other inorganic fiber fillers may include oxide fibers such as titania and silica, alkaline earth silicate wool (AES), and refractory ceramic fiber (RCF).

[0019] The inorganic fiber filler may contain alumina fibers having a true specific gravity of at least 3.0, preferably at least 3.1, and more preferably at least 3.2. This improves the mechanical strength of the heat-resistant plate. The upper limit of the true specific gravity of the alumina fibers is not particularly limited, but is, for example, 3.8 or less, preferably 3.7 or less, and more preferably 3.6 or less. This allows for weight reduction.

[0020] The alumina / silica mass ratio of the alumina fibers may be, for example, 80 / 20 to 99 / 1, and preferably 97 / 3 to 90 / 10, which can improve durability against reducing substances or alkaline substances. In this specification, unless otherwise specified, the symbol "to" indicates that the upper and lower limits are included.

[0021] The upper limit of the alumina fiber content is, for example, 85 parts by mass or less, preferably 80 parts by mass or less, and more preferably 75 parts by mass or less, per 100 parts by mass of the total of the inorganic fiber filler, inorganic porous filler, and inorganic binder, thereby suppressing an increase in thermal conductivity at high temperatures. On the other hand, the lower limit of the alumina fiber content is, for example, 10 parts by mass or more, preferably 20 parts by mass or more, and more preferably 30 parts by mass or more, relative to 100% by mass of the total of the inorganic fiber filler, inorganic porous filler, and inorganic binder, which can reduce the bulk density of the heat-resistant plate member.

[0022] The alumina fibers may contain mullite (3Al2O3·2SiO2). The mineral composition of the alumina fibers can be identified and quantified by powder X-ray diffraction.

[0023] The upper limit of the mullite content in the alumina fibers is, for example, 80 mass % or less, preferably 20 mass % or less, and more preferably 12 mass % or less, which can improve the fiber strength. On the other hand, the lower limit of the mullite content in the alumina fibers may be, for example, 1 mass % or more.

[0024] The upper limit of the shot (non-fibrous particle) content of alumina fiber having a length of 50 μm or more, measured in accordance with ISO 10635, is, for example, 10% or less, preferably 5% or less, and more preferably 3% or less. By using alumina fiber with reduced shot, manufacturing variations can be reduced. On the other hand, the lower limit of the shot content is not particularly limited, but may be 0.1% or more.

[0025] The shape of the alumina fibers is not limited, but bulk alumina fibers can be used.

[0026] Although known methods can be used to produce alumina fibers, a method including the following steps of preparing a stock solution, spinning, collecting fibers, and calcining can also be used. This allows bulk alumina fibers (cotton-like fibers) to be produced.

[0027] (Stock solution preparation process) Examples of the alumina source include an aqueous aluminum oxychloride solution and alumina sol, and examples of the silica source include silica sol and polysiloxane. If necessary, a spinning aid such as polyvinyl alcohol or polyethylene glycol can be used. These ingredients are mixed in a desired ratio and concentrated under reduced pressure to obtain a spinning dope.

[0028] (Spinning process) The spinning dope prepared in the dope preparation step is extruded into the atmosphere through the pores using a spinning device to form an alumina fiber precursor. There are no particular limitations on the spinning device used, and a blowing spinning device, a rotating disk spinning device, or the like can be used. From the viewpoint of preventing fusion of the fibers extruded through the pores and producing alumina fibers with high surface pressure, the rotating disk spinning method described in JP 2010-31416 A is preferably used.

[0029] By adjusting the pore size and extrusion conditions, it is possible to control the average fiber diameter and fiber diameter distribution of the resulting alumina fibers, as well as the content of non-fibrillated material called shot. Typically, the average fiber diameter of the alumina fibers is adjusted to a range of 3 μm to 8 μm. Note that the content of shots with a length of 50 μm or more is preferably less than 1%.

[0030] (cotton collection process) The alumina fiber precursor obtained in the spinning process is collected by suction from the bottom of a net conveyor installed in a collection chamber, and an aggregate of the alumina fiber precursor is obtained. The thickness and surface weight of the resulting aggregate can be adjusted by adjusting the speed of the net conveyor.

[0031] (Firing process) The alumina fiber precursor obtained in the fiber collecting step is calcined in a calcining step, in which a degreasing step and a crystallization step are carried out in this order using a calcining device.

[0032] The heat-resistant plate member contains an inorganic porous filler. The inorganic porous filler includes calcium aluminate porous particles (hereinafter, may be referred to as CA6 particles) containing CaO·6Al2O3 as a mineral phase.

[0033] The CA6 particles may contain other mineral phases as needed. Examples of other mineral phases include 3CaO·Al2O3, CaO·Al2O3, and CaO·2Al2O3. These may be used alone or in combination of two or more.

[0034] The particle size of the CA6 particles is, for example, 0.5 to 500 μm, preferably 1 to 300 μm, and more preferably 1.5 to 200 μm.

[0035] The bulk density of CA6 particles is, for example, 0.4 to 1.0 g / cm 3 , preferably 0.5 to 0.9 g / cm 3 , more preferably 0.6 to 0.8 g / cm 3 is.

[0036] The CA6 particles can be produced by, for example, mixing or mixing and grinding aggregate raw materials such as calcia raw materials and alumina raw materials, blending them so that the molar ratio of CaO to Al2O3 in the finally synthesized calcium aluminate is approximately 1:6, kneading them with water, molding them, and then firing them at a temperature of 1000°C to 1700°C, and grinding the resulting product in a grinder.

[0037] The lower limit of the content of the inorganic porous filler is, for example, 1 part by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, per 100 parts by mass of the total of the inorganic fiber filler, the inorganic porous filler, and the inorganic binder, which can improve the weight and heat insulation. On the other hand, the upper limit of the content of the inorganic porous filler is, for example, 70 parts by mass or less, preferably 65 parts by mass or less, and more preferably 60 parts by mass or less, relative to 100 parts by mass of the total of the inorganic fiber filler, the inorganic porous filler, and the inorganic binder. This makes it possible to further reduce the weight.

[0038] The heat-resistant plate member may contain a binder selected from at least one of an inorganic binder and an organic binder. The organic binder can bind inorganic fillers such as inorganic fiber fillers and inorganic porous fillers together in the papermaking body. The use of an inorganic binder that remains after firing can reduce the heat shrinkage rate of the heat-resistant plate member.

[0039] The inorganic binder may include one or more selected from the group consisting of colloidal silica and alumina sol.

[0040] The content of the inorganic binder is, for example, 1% by mass to 10% by mass, and preferably 3% by mass to 7% by mass, calculated as the solid content in the inorganic binder, relative to 100% by mass of the total of the inorganic fiber filler, inorganic porous filler, and inorganic binder.

[0041] The organic binder may contain one or more selected from the group consisting of polyvinyl alcohol, polyethylene oxide, polyethylene glycol, starch, (meth)acrylic acid ester copolymer, and polyoxyethylene alkyl ether. In addition, adhesives such as epoxy-based, phenol-based, acrylic acid ester-based, polyurethane-based, isocyanate-based, polyimide-based, and vinyl acetate-based adhesives, as well as various rubber-based adhesives, may also be used as the organic binder.

[0042] As the (meth)acrylic acid ester copolymer, for example, a copolymer of (meth)acrylic acid esters, a copolymer of a (meth)acrylic acid ester and a monomer other than a (meth)acrylic acid ester, or the like can be used.

[0043] The content of the organic binder is, for example, 1% by mass to 10% by mass, and preferably 3% by mass to 7% by mass, relative to 100% by mass of the total of the inorganic fiber filler, inorganic porous filler, and inorganic binder.

[0044] The heat-resistant plate is made of a molded paper product, that is, the heat-resistant plate is obtained by papermaking a slurry containing raw material components and molding the slurry.

[0045] The method for producing the heat-resistant plate member includes, for example, a slurry process, a paper-making process, and a molding process.

[0046] In the slurry process, a fibrous material such as an inorganic fiber filler, an inorganic porous filler, an inorganic binder, or an organic binder is dissolved or dispersed in water to prepare an aqueous slurry. The aqueous slurry may contain additives commonly used in papermaking methods, such as a flocculant, as needed.

[0047] Next, in the papermaking process, the resulting slurry is passed through a screen with a specified mesh to remove the water from the slurry, leaving the fiber raw material on the screen to obtain a paper product. Suction may be performed from below the screen. Drying may be performed after or during dehydration. The surface shape of the screen may be selected as appropriate and may be flat or may have a three-dimensional structure in part.

[0048] Examples of papermaking methods include a method in which a water slurry is poured into a box-shaped container equipped with a mesh plate on the bottom, dewatered while being suctioned below the mesh, and the cake on the mesh surface is dried, a method in which a flat mesh equipped with a suction mechanism is submerged in the water slurry, and the cake that is strained out by suction is dried, and a method using continuous papermaking equipment such as a cylinder papermaking machine or a Fourdrinier papermaking machine. The cake may also be dried by hot air drying.

[0049] In this specification, the term "paper product" is a technical term generally used to indicate the state of an object obtained by using a technique for filtering fibrous materials.

[0050] The resulting molded article is then heated in the molding step to produce a molded article of a predetermined shape. For example, a heat and pressure treatment may be performed using a press. The molded article may be processed into a board.

[0051] The thickness of the heat-resistant plate member made of a papermaking molded article is not particularly limited, but may be 1 mm to 100 mm, and preferably 10 mm to 60 mm, which makes it possible to realize a heat-resistant plate member that is easy to handle.

[0052] The upper limit of the bulk density of the heat-resistant plate member after firing at 1400°C for 60 minutes is, for example, 0.30 (g / cm 3 ), preferably less than 0.28 (g / cm 3 ) or less, more preferably 0.25 (g / cm 3 On the other hand, the lower limit of the bulk density of the heat-resistant plate member is 0.10 (g / cm 3 ) or more is also acceptable.

[0053] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0054] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the descriptions of these examples.

[0055] <Production of heat-resistant plate members> The ingredients of each raw material shown in Table 1 are as follows: (inorganic fiber filler) Alumina fiber (manufactured by Denka, product name: B80, composition (mass ratio) Al2O3:SiO2 = 80%:20%, bulk, true specific gravity: 3.4, average fiber length (diameter): 4.1 μm, mullite content: 59%, shot content of 50 μm or longer measured in accordance with ISO 10635: 1.0%) (inorganic porous filler) CA6 particles: (Calcium aluminate porous particles containing CA6 as the main component, manufactured by Denka Co., Ltd., average particle size: 18.5 μm, bulk density: 0.71 g / cm 3 ) (inorganic non-porous filler) Alumina powder: (Sumitomo Chemical Co., Ltd., product name AM-210, average particle size: 4.8 μm, bulk density: 1.28 g / cm 3 ) (inorganic binder) Colloidal silica (solid concentration 20% by mass, manufactured by Nissan Chemical Industries, Ltd.) (organic binder) Starch (manufactured by Nippon Starch Chemical Co., Ltd.)

[0056] Example 1 Using the raw material components shown in Table 1, 78 parts by mass of alumina fiber, 16 parts by mass of CA6 particles, 6 parts by mass of colloidal silica (solid content concentration 20% by mass) converted to solids, and 5 parts by mass of starch were added per 100 parts by mass of inorganic filler (inorganic fiber filler / inorganic porous filler) and inorganic binder combined, and wet mixed for 20 minutes to prepare an aqueous slurry (mixture) with a slurry concentration of 2.0% by mass (total content of inorganic fiber filler, inorganic porous filler, organic binder, and inorganic binder). The resulting water slurry was poured into a papermaking box with a bottom mesh dimension of 320 mm x 320 mm (mesh spacing 0.3 mm), and water was removed by suction from below the bottom mesh to produce a sheet-shaped paper product (cake). After demolding, the plate-shaped paper molded body was clamped in a press, the thickness was adjusted, and then it was dried in a hot air dryer at 100°C for 16 hours to produce a plate-shaped paper molded body (heat-resistant plate member A) with a thickness of 25 mm.

[0057] Example 2 A heat-resistant plate member B was produced in the same manner as in Example 1, except that the amount of alumina fibers was changed to 56 parts by mass and the amount of CA6 particles was changed to 37 parts by mass.

[0058] Example 3 A heat-resistant plate member C was produced in the same manner as in Example 1, except that the amount of alumina fibers was changed to 40 parts by mass and the amount of CA6 particles was changed to 53 parts by mass.

[0059] (Comparative Example 1) A heat-resistant plate member D was produced in the same manner as in Example 1, except that the CA6 particles were replaced with alumina powder.

[0060] (Reference example) A heat-resistant plate member E was produced in the same manner as in Example 1, except that the amount of alumina fiber was changed to 94 parts by mass and CA6 particles were not used.

[0061] [Table 1]

[0062] The obtained heat-resistant plate members A to E were evaluated based on the following evaluation items. The evaluation results are shown in Table 1.

[0063] (bulk density) The heat-resistant plate member was baked at 1400°C for 60 minutes, and then its weight was measured using a weighing scale and its volume was measured using a vernier caliper. The bulk density (g / cm) was calculated by dividing the measured weight by the volume. 3 ) was calculated.

[0064] (thermal conductivity) The thermal conductivity of the heat-resistant plate members was measured in the temperature range from room temperature (RT) to 1400°C in accordance with JIS R2251-1. Table 1 shows the thermal conductivity (W / m K) at room temperature, 600°C, 1000°C, and 1400°C.

[0065] The heat-resistant plate members of Examples 1 to 3 exhibited lower thermal conductivity and better thermal insulation at high temperatures such as 1000°C and 1400°C than those of Reference Example and Comparative Example 1. Furthermore, the heat-resistant plate member of Example 1 had a lower bulk density after firing and was lighter in weight than Comparative Example 1, which had the same compositional components and compositional ratios except for the inorganic porous filler. Therefore, it was found that the heat-resistant plate members of Examples 1 to 3 were lightweight and had excellent heat insulating properties. The heat-resistant plate members of such Examples can be suitably used as high-temperature fire-resistant heat insulating materials.

[0066] This application claims priority based on Japanese Patent Application No. 2021-181730, filed on November 8, 2021, the disclosure of which is incorporated herein in its entirety.

Claims

1. A heat-resistant plate member made of a papermaking molded body containing an inorganic fiber filler and an inorganic porous filler, the inorganic fiber filler includes alumina fibers, The inorganic porous filler is CaO.6Al ２ O ３ Including, After firing at 1400 ° C. for 60 minutes, the bulk density of the heat-resistant plate member is 0.10 g / cm ３ 0.30g / cm or more ３ A heat-resistant plate member having a thickness of less than 1 / 2 mm.

2. The heat-resistant plate member according to claim 1, The heat-resistant plate member has a content of the alumina fibers of 10 parts by mass or more and 85 parts by mass or less per 100 parts by mass of the total of the inorganic fiber filler, the inorganic porous filler, and the inorganic binder.

3. The heat-resistant plate member according to claim 1 or 2, The alumina fiber has a true specific gravity of 3.0 or more and 3.8 or less, and Al ２ O ３ and SiO ２ A heat-resistant plate member having the above structure.

4. The heat-resistant plate member according to claim 1 or 2, The heat-resistant plate member, wherein the alumina fibers have a mullite content of 1% by mass or more and 80% by mass or less.

5. The heat-resistant plate member according to claim 1 or 2, A heat-resistant plate member, wherein the alumina fiber has a shot content of 50 μm or more in length, measured in accordance with ISO 10635, of 0.1% or more and 10% or less.

6. The heat-resistant plate member according to claim 1 or 2, A heat-resistant plate member, wherein the content of the inorganic porous filler is 1 part by mass or more and 70 parts by mass or less per 100 parts by mass of the total of the inorganic fiber filler, the inorganic porous filler, and the inorganic binder.

7. The heat-resistant plate member according to claim 1 or 2, A heat-resistant plate member comprising a binder selected from at least one of an inorganic binder and an organic binder.

8. The heat-resistant plate member according to claim 7, The heat-resistant plate member, wherein the inorganic binder comprises one or more selected from the group consisting of colloidal silica and alumina sol.

9. The heat-resistant plate member according to claim 7, The heat-resistant plate member, wherein the organic binder comprises one or more selected from the group consisting of polyvinyl alcohol, starch, polyethylene glycol, (meth)acrylic acid ester copolymer, and polyoxyethylene alkyl ether.

10. A structure comprising the heat-resistant plate member according to claim 1 or 2.

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