Thermal insulation material and method for manufacturing the same

Abstract

The present invention provides an insulating material that possesses desirable thermal insulation properties in addition to good flexibility. [Solution] A mixture of inorganic fine particles 1 made of metal oxide as the main material, fire-resistant fibers 2, infrared scattering material 3, and preferably a fused resin binder 4 made of organic fibers, with a bulk density of 200 kg / m³. 3 More than 500kg / m 3 The material consists of the following sheet-like molded body, in which fire-resistant fibers 2 are randomly oriented in a direction substantially perpendicular to the thickness direction of the molded body, preferably having a heat resistance temperature of 1000°C or more and 1200°C or less, and a thermal conductivity of 0.05 W / (m·K) or less at 600°C.

Description

[Technical Field]

[0001] This invention relates to an insulating material that combines desired thermal insulation properties and flexibility, and to a method for manufacturing the same. [Background technology]

[0002] Industrial furnaces such as heating furnaces, heat treatment furnaces, drying furnaces, boilers, kilns, and incinerators are used in various industrial fields such as metal smelting, petrochemicals, and ceramics. In these industrial furnaces and their surrounding equipment, in order to suppress heat radiation from the inside to the outside of the furnace body and minimize energy consumption, insulation material is installed as an inner lining not only on the inside of the furnace body but also on the inner surfaces of ducts and chimneys connected to it. Furthermore, in furnace components that have internal passages for refrigerants such as cooling water, such as skid posts installed in walking beam type heating furnaces, insulation material is installed as an outer lining to prevent the refrigerant from being excessively heated by heat input from the outside.

[0003] The heated surfaces of equipment and machinery used in high-temperature atmospheres, such as the furnace walls inside industrial furnaces, the inner surfaces of ducts, and the outer surfaces of furnace components, are often curved. Therefore, insulation materials suitable for application to curved surfaces are required. To address this, insulation materials that can be freely bent to conform to the curved heated surface have been proposed. For example, Non-Patent Documents 1 and 2 disclose insulation materials in various forms such as quilt-like, quilt-like, and segmented shapes, which are made by covering a microporous insulation material consisting of nano-sized silica particles with a fibrous covering material and sewing it together. Furthermore, coated insulation materials have also been proposed in which a thin microporous insulation material is covered with an aluminum-coated glass cloth sheet or the like to allow it to be bent.

[0004] On the other hand, Patent Document 1 discloses a flexible thermal insulation material that can be bent along the outer surface of a tubular tube, for example. Specifically, it discloses a technique for producing the thermal insulation material by preparing a mixture by suspending fumed silica, a low thermal conductivity material, and silicon carbide, an infrared absorbing material, in a solvent such as hexane, filling the mixture into a textile fabric layer of a thermal insulation fabric, and then removing the solvent. Patent Document 2 also discloses a composite thermal insulation material in which a reinforcing material with a tensile strength of 60 N / 25 mm or more, made of inorganic or organic fibers, is bonded to at least one side of a molded body made of a low thermal conductivity material. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Catalog "High-Performance Insulation Material Microtherm," Japan Microtherm Co., Ltd., February 2004, page 5. [Non-Patent Document 2] Catalog "Porextherm WDS", Kurosaki Harima Co., Ltd., October 1, 2005, page 5. [Patent Documents]

[0006] [Patent Document 1] Japanese Public Publication No. 2022-508727 [Patent Document 2] Japanese Patent Publication No. 2016-205728 [Overview of the project] [Problems that the invention aims to solve]

[0007] While the use of the insulation materials described in Non-Patent Documents 1 and 2 above makes it possible to install them along curved surfaces, insulation materials that are sewn into bags can sometimes result in localized insufficient insulation or heat leakage at the joints or seams during installation, as the insulation material may be interrupted or thinner at those points. Furthermore, low thermal conductivity materials primarily composed of nano-sized particles have relatively low strength, which can lead to damage within the bag during handling or damage after installation due to static pressure or compressive stress caused by thermal expansion of refractory materials.

[0008] On the other hand, in the case of coated insulation materials in which microporous insulation material is covered with a covering material such as an aluminum-coated glass cloth sheet, the bending of the coated insulation material is restricted by the covering material. Therefore, if the curvature of the installation surface, which is the heated surface, becomes small, it may not be possible to freely bend the insulation material along the installation surface. In addition, since microporous insulation material is generally physically fragile, the microporous insulation material inside the covering material may be damaged when processing such as cutting or drilling for installation or during transportation.

[0009] Furthermore, the thermal insulation material in Patent Document 1 has a blanket bulk density of 110-220 kg / m³ in order to ensure flexibility, as shown in the examples. 3 The pressure is kept to a minimum. In this case, when compressive stress is applied to the insulation material, plastic deformation may occur, and in the areas where plastic deformation occurs, voids will be created after the compressive stress is reduced, thus reducing the insulation performance. On the other hand, in all of the examples 1 to 4 of the composite insulation material in Patent Document 2, glass fiber is used as the main material of the insulation fabric, so the glass transition temperature must be considered when determining the heat resistance temperature, which limits its applications. Since the insulation materials in Patent Documents 1 and 2 are all in the form of plate-shaped molded bodies, they are not suitable for construction methods that involve continuously wrapping them around pipes, skid pipes, etc.

[0010] This invention has been made in view of the problems of the conventional thermal insulation materials described above, and aims to provide a thermal insulation material that has not only the desired thermal insulation properties but also good flexibility. [Means for solving the problem]

[0011] In order to achieve the above object, the heat insulating material according to the present invention is a bulk density of 200 kg / m in which inorganic fine particles made of a metal oxide as a main material, refractory fibers, an infrared scattering material, and a fused resin binder are mixed 3 or more and 500 kg / m 3 or less, and is composed of a sheet-shaped molded body, and the refractory fibers are randomly oriented in a direction substantially perpendicular to the thickness direction of the molded body.

[0012] Further, the method for manufacturing a heat insulating material by a dry method according to the present invention includes a deposition step of depositing a mixture of inorganic fine particles made of a metal oxide as a main material, refractory fibers, an infrared scattering material, and a resin binder while dispersing it in an air flow flowing in the horizontal direction, and heating and compression molding the obtained deposit into a sheet shape, thereby thermally fusing the resin binder to at least the inorganic fine particles. It is characterized by having a molding step.

Effects of the Invention

[0013] According to the present invention, it is possible to provide a heat insulating material having desired heat insulating performance and flexibility. By using this heat insulating material, it becomes possible to wrap and construct it on a curved surface, so that even on a construction surface of a heat insulating object composed of a curved surface such as the inner wall surface of an industrial furnace or the skid posts of a walking beam type heating furnace, it is possible to perform heat insulating construction simply and reliably.

Brief Description of the Drawings

[0014] [Figure 1] It is a schematic longitudinal sectional view showing a specific example of the heat insulating material according to the present invention. [Figure 2] It is a schematic longitudinal sectional view showing a specific example of the manufacturing apparatus of the heat insulating material according to the present invention.

Modes for Carrying Out the Invention

[0015] 1. Heat Insulating Material The following describes embodiments of the thermal insulation material according to the present invention. As shown in Figure 1, the thermal insulation material of the embodiment of the present invention mainly consists of inorganic fine particles 1 made of inorganic oxides such as silica and alumina, and is made of a sheet-like molded body in which fire-resistant fibers 2, preferably in the form of a powder or granular infrared scattering material 3, and a resin binder 4 fused to the surrounding material are mixed together.

[0016] In the embodiment of the present invention, the mixing ratio (i.e., the content in the thermal insulation material) of the above-mentioned components is appropriately adjusted so that desired properties as a thermal insulation material can be obtained, taking into consideration the actions and effects performed by each of the above-mentioned components. Specifically, the preferred content of each component constituting the thermal insulation material of the embodiment of the present invention is preferably 40 to 82% by mass for inorganic fine particles 1, 5 to 40% by mass for fire-resistant fibers 2, 8 to 20% by mass for infrared scattering material 3, and 3 to 40% by mass for resin binder 4. Furthermore, it is preferable that these components are included in total at 98% by mass or more, and substances other than the above-mentioned components, such as unavoidable impurities and molding aids, may be included as long as their total is within a range of less than 2% by mass.

[0017] Of the materials described above, as indicated by the white arrows in the figure, the fire-resistant fibers 2 are randomly oriented in a direction approximately perpendicular to the thickness direction of the molded body, and if the resin binder 4 is fibrous, it is also randomly oriented in a direction approximately perpendicular to the thickness direction of the molded body. In other words, among the components of the sheet-like thermal insulation material, the fire-resistant fibers 2 and, in the case of fibrous resin binder 4, both extend approximately parallel to the sheet surface. Because of this characteristic morphology, the thermal insulation material of the embodiment of the present invention can increase the limit of deflection that can be bent without breaking compared to conventional materials. Furthermore, the thermal insulation performance can be enhanced by including the infrared scattering material 3 and the fire-resistant fibers 2.

[0018] The characteristic form in which the above refractory fiber 2 and the resin binder 4 in the fibrous state extend substantially parallel to the sheet surface can be formed, as will be described later, by blowing air from the horizontal direction against the raw material mixture and depositing the raw material mixture while dispersing it in an air flow flowing horizontally during the process of freely dropping the raw material mixture to form a deposit. Further, as will be described later, the above fused resin binder 4 can be formed by heating and compressing during the process of forming a molded body from the deposit. Thus, by fusing the resin binder 4 to at least the group of inorganic fine particles 1 existing around, the resin binder 4 can be made to serve as an adhesive.

[0019] In addition to the above excellent flexibility, the heat insulating material of the embodiment of the present invention has a bulk density in the range of 200 kg / m 3 or more and 500 kg / m 3 or less, and preferably in the range of 250 kg / m 3 or more and 350 kg / m 3 or less. Thereby, it becomes possible to provide a heat insulating material having both a compressive strength that is not easily damaged by the compressive stress due to the thermal expansion of the heat insulating object while ensuring the desired heat insulating property and excellent flexibility. If this bulk density is less than 200 kg / m 3 , sufficient compressive strength and amount of deflection cannot be obtained, and there is a risk that the handling property will also become insufficient. Conversely, if this bulk density exceeds 500 kg / m 3 , the compressive strength becomes too high and good flexibility cannot be obtained.

[0020] Further, as the heat insulating performance, the heat insulating material of the embodiment of the present invention can suppress the thermal conductivity at 600 °C to 0.05 W / (m·K) or less. Thereby, the amount of heat dissipated from the heat insulating object can be effectively reduced and the consumption of thermal energy can be suppressed. Further, since the heat insulating material of the embodiment of the present invention has heat resistance with a heat resistance temperature of 1000 °C or more and 1200 °C or less, when the normal use temperature of the heat insulating object is 1000 °C or less, the desired heat insulating property can be maintained for an extremely long period.

[0021] The thermal insulation material of the embodiment of the present invention can be molded into a long sheet shape by continuous molding. In this case, the long sheet-shaped molded body can be wound onto a rotating roll from its leading edge to form a rolled shape. As mentioned above, the thermal insulation material of the embodiment of the present invention has excellent flexibility, so if it is molded into a long sheet shape with a thickness of approximately 0.5 to 5 mm, for example, it can be wound onto a rotating roll with an outer diameter of approximately 50 to 150 mm without causing cracks or other damage. Next, each component of the thermal insulation material of the embodiment of the present invention having the above features will be described in detail.

[0022] (1) Inorganic fine particles The inorganic fine particles consist of a metal oxide having a heat resistance temperature of approximately 1000 to 1200°C. Preferably, one or more of silica, alumina, and zirconia are used as the metal oxide. While silica has a heat resistance temperature of approximately 1000°C, using alumina or zirconia in place of silica, or in addition to silica, can increase the heat resistance temperature to approximately 1200°C. Therefore, if the normal operating temperature of the object to be insulated is 1000°C or lower, the desired insulation performance can be maintained for an extremely long period. Preferably, the average particle size of these inorganic fine particles is 0.5 μm or less. This allows for a small reduction in the size of the voids between the inorganic fine particles and the refractory fibers or infrared scattering material, thereby suppressing convective heat transfer of gases at high temperatures. In this specification, the average particle size refers to the 50% diameter (D50) based on volume measured by a laser diffraction particle size distribution analyzer.

[0023] (2) Fire-resistant fiber Refractory fibers are fibers made of an inorganic composition having a heat resistance temperature of approximately 600 to 1600°C. Typical refractory fibers are not limited to glass short fibers, glass long fibers, alumina fibers, mullite fibers, zirconia fibers, silica-alumina fibers, and AES (alkali earth silicate) fibers. It is preferable to use one or more selected from the group consisting of these fibers. These refractory fibers may also contain non-fibrous particles of the same material. In this case, the content of non-fibrous particles is preferably 60 parts by mass or less, and more preferably 50 parts by mass or less, per 100 parts by mass of refractory fibers. In particular, it is preferable that the amount of non-fibrous particles with an average particle size of 425 μm or more be 3 parts by mass or less, and more preferably 1 part by mass or less.

[0024] The above-mentioned fire-resistant fibers preferably have an average fiber diameter of 1 μm to 13 μm, and more preferably 2 μm to 10 μm. Here, the average fiber diameter is calculated by taking an image of the fiber group to be measured with an electron microscope, measuring the distance in the width direction of 200 fibers arbitrarily selected from the obtained image, and taking the arithmetic mean. Furthermore, the above-mentioned fire-resistant fibers preferably have an average fiber length of 0.5 mm to 30 mm, and more preferably 1 mm to 10 mm. Here, the average fiber length is calculated by taking an image of the fiber group to be measured with an electron microscope, measuring the straight-line distance from end to end in the longitudinal direction of 100 fibers arbitrarily selected from the obtained image, and taking the arithmetic mean. By using fire-resistant fibers having the above-mentioned average fiber diameter and average fiber length, they can be extended almost parallel to the sheet surface of the thermal insulation material.

[0025] (3) Infrared scattering material The infrared scattering material is not particularly limited as long as it has a heat resistance temperature of 800°C or higher and is made of a composition that can reduce heat transfer by radiation, but it is preferable that it is infrared reflector. Examples of such compositions include silicon carbide, titanium dioxide, zirconium silicate, etc., and it is preferable to use one or more selected from the group consisting of these compositions. Furthermore, it is preferable that the average particle size of this infrared scattering material is 0.1 μm or more and 3.0 μm or less, and in particular, the upper limit is more preferably 2.0 μm or less, which is an average particle size that is about the same as the peak wavelength of infrared radiation at 1200°C that causes radiative heat transfer.

[0026] (4) Resin binder The resin binder is not particularly limited in material as long as it can be welded to surrounding components by heating, but it is preferably one that begins to soften or melt at around 130°C or lower, more preferably around 150°C or lower. Examples of such materials include polyester, polyvinyl alcohol, polyethylene, polypropylene, or combinations of two or more of these. In particular, the resin binder is preferably composed of polyethylene / polypropylene core-sheath structure fibers, which is preferable because it allows the core portion to remain after melting, thereby obtaining higher flexibility. The above-mentioned core-sheath structure fiber refers to a fiber having a double structure in which a core portion made of polypropylene and a sheath portion made of polyethylene, for example, surrounds the core portion in a substantially concentric manner and has a lower melting point than the core portion.

[0027] As described above, the resin binder is preferably fibrous, and in this case, similar to the fire-resistant fibers described above, the resin binder can be randomly oriented in a direction substantially perpendicular to the thickness direction of the heat insulating material, which is made of a sheet-like molded body. This further enhances the excellent flexibility, which is a characteristic of the heat insulating material of the embodiment of the present invention.

[0028] When the resin binder is fibrous, it is preferable that the fiber thickness scale T (dtex), obtained by substituting the fiber length L (in meters) and mass W (in grams) of each fiber into the formula "T = (10000 × W) / L), is within the range of 0.15 to 20 dtex. Furthermore, when the resin binder is fibrous, it is preferable that the average fiber length, determined by measurement using an electron microscope, is within the range of 3 to 20 mm, similar to the case of the refractory fiber described above.

[0029] 2. Method for manufacturing thermal insulation materials Next, a method for manufacturing the thermal insulation material according to the embodiment of the present invention described above will be explained. First, in the mixing step, the inorganic fine particles, fire-resistant fibers, infrared scattering material, and resin binder, weighed out to a predetermined mixing ratio, are loaded into a mixer and mixed to prepare a raw material mixture. Next, in the deposition step, the raw material mixture is deposited by being dispersed in a horizontally flowing airflow and allowed to free fall, so that the fire-resistant fibers and fibrous resin binder are oriented horizontally.

[0030] During the deposition process described above, it is preferable to deposit the raw material mixture on a breathable material such as a mesh wire and adsorb the raw material mixture onto the upper surface of the material by suction from below. The deposited material is then subjected to a molding process where it is heat-treated at a temperature of approximately 130-150°C while applying pressure in the thickness direction and heat-pressed, either in its original state or with multiple layers of material stacked on top of each other. This melts at least the outer periphery of the resin binder, causing the resin binder to heat-weld to at least the inorganic fine particles present around it. During this heat welding, it is preferable to heat-weld adjacent resin binders to each other at one or more locations.

[0031] The method for manufacturing the thermal insulation material according to the above embodiment of the present invention can be suitably carried out, for example, by the manufacturing apparatus shown in Figure 2. Specifically, the manufacturing apparatus shown in Figure 2 consists of a substantially cylindrical chamber 11 equipped with a raw material supply port 11a at the top and a gas exhaust port 11c at the bottom. The raw material mixture introduced from the raw material supply port 11a freely falls within the chamber 11 toward a mesh conveyor 12 that has a conveying path extending horizontally at the bottom of the chamber 11. During this free fall, the raw material mixture is dispersed by a velocity-controlled airflow blown horizontally from an air outlet 11b located in the middle of the height of the chamber 11. As a result, the refractory fibers and, in the case of fibrous resin binders, contained in the raw material mixture are oriented horizontally and accumulate on the conveyor surface of the mesh conveyor 12 in this oriented state.

[0032] Since the air blown into the chamber 11 is constantly exhausted from the gas exhaust port 11c, which is located below the conveying path of the mesh conveyor 12, through the conveyor surface of the mesh conveyor 12, the deposits of the raw material mixture that accumulate on the conveyor surface of the mesh conveyor 12 are compacted by being sucked onto the conveyor surface by the airflow passing through the conveyor surface.

[0033] The compacted deposit described above is transported out of the chamber 11 by a continuously moving mesh conveyor 12 and introduced into the heating press 13 either in its original state or stacked in multiple layers together with separately formed deposits. The heating press 13 has one or more pairs of rollers, and the deposit is sandwiched between these rollers from both sides, applying pressure in the thickness direction while being continuously heat-treated under ambient temperature conditions of approximately 130-150°C. As a result, at least the surface portion of the resin binder melts and heat-weldes to at least inorganic fine particles present around it, forming an insulating material consisting of a long sheet-like molded body.

[0034] The resulting long sheet-like insulation material can be continuously wound onto a rotating roller from its leading edge to form a cylindrical insulation roll 14. By forming the final insulation material into a roll, handling during storage and transportation becomes easier. Furthermore, during insulation installation, the long sheet-like insulation material can be spirally wrapped around the outer surface of pipes and skid pipes, or continuously wrapped with the longitudinal direction of the long sheet-like insulation material aligned with the central axis of the pipes, etc. This allows for efficient insulation installation while minimizing the occurrence of heat leaks. [Examples]

[0035] Thermal insulation materials for the examples and comparative examples of the present invention were prepared using multiple raw material mixtures prepared by varying the mixing ratios of the constituent elements, and each of them was evaluated from the viewpoint of windability, bulk density, flexibility, compressive strength, thermal insulation, and heat resistance, as defined below. Specifically, windability was evaluated by whether or not a test piece with a thickness of 2 mm and a length of 300 mm broke when wound around a paper tube with an outer diameter of 100 mm (i.e., poor "×") (i.e., good "○"). Bulk density was determined by dividing mass by volume. Flexibility was evaluated in a three-point bending test using a strength testing machine, by the maximum amount of deflection when a 5 mm thick test piece, placed on two supports spaced 100 mm apart, was pressed down on its center and broke. Compressive strength was evaluated by the maximum load when compressed using a strength testing machine and the strain reached 10%. Thermal insulation was evaluated by the thermal conductivity at 600°C, in accordance with the plate comparison method (JIS A1412-2 Annex A). Heat resistance was evaluated by the highest temperature at which the thermal shrinkage rate after heating the test specimen for 24 hours was 3% or less.

[0036] [Example 1] A raw material mixture was prepared by weighing out and mixing the following materials in a mixer: 75% by mass of silicate fine particles (average particle size 0.2 μm) as inorganic fine particles, 5% by mass of glass long fibers (average fiber diameter 13 μm, average fiber length 13 mm) as refractory fibers, 15% by mass of silicon carbide (average particle size 2 μm) as an infrared scattering material, and 5% by mass of polyethylene / polypropylene core-sheath structure fibers (fiber diameter 1.7 dtex, average fiber length 5 mm) as a resin binder.

[0037] The raw material mixture was introduced from the top into the chamber 11 of the manufacturing apparatus shown in Figure 2 and allowed to freefall toward the bottom. The raw material mixture was then deposited on the conveyor surface of the mesh conveyor 11 located at the bottom of the chamber 11. At this time, air was introduced from the air outlet 11b to create a horizontal airflow with controlled airflow velocity within the chamber 11, thereby orienting the fibers contained in the raw material mixture horizontally. In addition, the raw material mixture deposited on the conveyor surface was compacted by continuously exhausting air from the gas exhaust port 11c located at the bottom of the chamber 11.

[0038] The compacted sediment described above was continuously transported out of the chamber 11 by a mesh conveyor 11 and directly introduced into a heating press 13, where it was heated and compressed at 150°C to produce a thermal insulation material sample 1 consisting of a long sheet-like molded body. The resulting thermal insulation material sample 1 had good winding properties and a bulk density of 320 kg / m³. 3 The deflection was 17.8 mm, the compressive strength was 7.8 MPa, the thermal conductivity was 0.03 W / (m·K), and the heat resistance temperature was 1000°C.

[0039] [Example 2] To investigate the effect of bulk density on the properties of thermal insulation materials, thermal insulation materials for samples 2 and 3 were prepared in the same manner as in Example 1, except that the deposited material was heated and compressed so that the deposit height was approximately 0.6 times and approximately 1.5 times that of Example 1, respectively. The thermal insulation material for sample 2 obtained had good windability and a bulk density of 200 kg / m². 3The deflection was 15.2 mm, the compressive strength was 4.8 MPa, the thermal conductivity was 0.03 W / (m·K), and the heat resistance temperature was 1000°C. On the other hand, the insulation material of sample 3 had good winding properties and a bulk density of 500 kg / m 3 The material had a deflection of 15.3 mm, a compressive strength of 8.8 MPa, a thermal conductivity of 0.03 W / (m·K), and a heat resistance temperature of 1000°C.

[0040] [Example 3] To investigate the effect of the inorganic fine particle content on the properties of the thermal insulation material, a thermal insulation material sample 4, consisting of a long sheet-shaped molded body, was prepared in the same manner as in Example 1, except that the inorganic fine particle content was changed from 75% by mass to 40% by mass, and the resin binder content was changed from 5% by mass to 40% by mass. Furthermore, a thermal insulation material sample 5, consisting of a long sheet-shaped molded body, was prepared in the same manner as in Example 1, except that the inorganic fine particle content was changed from 75% by mass to 82% by mass, the resin binder content was changed from 5% by mass to 3% by mass, and the infrared scattering material was changed from 15% by mass to 10% by mass.

[0041] The obtained sample 4 insulation material had good winding properties and a bulk density of 340 kg / m². 3 The deflection was 16.5 mm, the compressive strength was 7.6 MPa, the thermal conductivity was 0.04 W / (m·K), and the heat resistance temperature was 1000°C. On the other hand, the insulation material of sample 5 had good winding properties and a bulk density of 250 kg / m 3 The deflection was 15.1 mm, the compressive strength was 5.1 MPa, the thermal conductivity was 0.03 W / (m·K), and the heat resistance temperature was 1000°C.

[0042] [Example 4] To investigate the effect of the material of inorganic fine particles on the properties of the thermal insulation material, thermal insulation materials, samples 6 and 7, consisting of long sheet-like molded bodies, were prepared in the same manner as in Example 1, except that alumina fine particles (average particle size 0.2 μm) and zirconia fine particles (average particle size 0.2 μm) were used instead of silica fine particles. The thermal insulation material of sample 6 obtained had good windability and a bulk density of 310 kg / m². 3The deflection was 16.5 mm, the compressive strength was 7.9 MPa, the thermal conductivity was 0.03 W / (m·K), and the heat resistance temperature was 1200°C. On the other hand, the insulation material of sample 7 had good winding properties and a bulk density of 300 kg / m 3 The deflection was 16.5 mm, the compressive strength was 6.6 MPa, the thermal conductivity was 0.03 W / (m·K), and the heat resistance temperature was 1200°C.

[0043] [Example 5] To investigate the effect of the fire-resistant fiber material on the properties of the thermal insulation material, thermal insulation materials consisting of long sheet-like molded bodies, samples 8 to 13, were prepared in the same manner as in Example 1, except that the fire-resistant fibers used were glass short fibers (average fiber diameter 13 μm), alumina fibers (average fiber diameter 5 μm), mullite fibers (average fiber diameter 6 μm), zirconia fibers (average fiber diameter 5 μm), silica-alumina fibers (average fiber diameter 3 μm), and AES (alkali earth silicate) fibers (average fiber diameter 3 μm, with a non-fibrous particle content of 50 parts by mass per 100 parts by mass of fire-resistant fibers, and 1 part by mass of non-fibrous particles with an average particle size of 425 μm or larger).

[0044] The obtained sample 8 insulation material had good winding properties and a bulk density of 340 kg / m². 3 The deflection was 16.5 mm, the compressive strength was 7.6 MPa, the thermal conductivity was 0.04 W / (m·K), and the heat resistance temperature was 1000°C. The insulation material of sample 9 had good winding properties and a bulk density of 340 kg / m 3 The material exhibited a deflection of 16.5 mm, a compressive strength of 6.8 MPa, a thermal conductivity of 0.05 W / (m·K), and a heat resistance temperature of 1000°C. The insulation material of sample 10 had good winding properties and a bulk density of 340 kg / m². 3 The material exhibited a deflection of 17.0 mm, a compressive strength of 6.9 MPa, a thermal conductivity of 0.05 W / (m·K), and a heat resistance temperature of 1000°C. The insulation material of sample 11 had good winding properties and a bulk density of 340 kg / m². 3 The material exhibited a deflection of 16.5 mm, a compressive strength of 7.1 MPa, a thermal conductivity of 0.05 W / (m·K), and a heat resistance temperature of 1000°C. The insulation material of sample 12 had good winding properties and a bulk density of 340 kg / m². 3The material exhibited a deflection of 17.5 mm, a compressive strength of 7.3 MPa, a thermal conductivity of 0.04 W / (m·K), and a heat resistance temperature of 1000°C. The insulation material of sample 13 had good winding properties and a bulk density of 340 kg / m². 3 It had a deflection of 16.5 mm, a compressive strength of 7.1 MPa, a thermal conductivity of 0.04 W / (m·K), and a heat resistance temperature of 1000°C.

[0045] [Example 6] To investigate the effect of the content of fire-resistant fibers and infrared scattering materials on the properties of thermal insulation materials, a thermal insulation material sample 14, consisting of a long sheet-shaped molded body, was prepared in the same manner as in Example 1, except that the proportion of inorganic fine particles was changed from 75% by mass to 40 parts by mass, and the proportion of fire-resistant fibers was changed from 5% by mass to 40 parts by mass. A thermal insulation material sample 15, consisting of a long sheet-shaped molded body, was prepared in the same manner as in Example 1, except that the proportion of fire-resistant fibers was changed from 5% by mass to 12 parts by mass, and the proportion of infrared scattering material was changed from 15% by mass to 8 parts by mass. Furthermore, a thermal insulation material sample 16, consisting of a long sheet-shaped molded body, was prepared in the same manner as in Example 1, except that the proportion of inorganic fine particles was changed from 75% by mass to 70 parts by mass, and the proportion of infrared scattering material was changed from 15% by mass to 20 parts by mass.

[0046] The obtained sample 14 insulation material had good winding properties and a bulk density of 360 kg / m². 3 The material exhibited a deflection of 15.5 mm, a compressive strength of 7.6 MPa, a thermal conductivity of 0.05 W / (m·K), and a heat resistance temperature of 1000°C. The insulation material of sample 15 had good winding properties and a bulk density of 340 kg / m². 3 The material exhibited a deflection of 17.3 mm, a compressive strength of 7.2 MPa, a thermal conductivity of 0.04 W / (m·K), and a heat resistance temperature of 1000°C. The insulation material of sample 16 had good winding properties and a bulk density of 340 kg / m². 3 The deflection was 17.2 mm, the compressive strength was 7.1 MPa, the thermal conductivity was 0.05 W / (m·K), and the heat resistance temperature was 1000°C.

[0047] [Example 7] To investigate the effect of the infrared scattering material on the properties of the thermal insulation material, thermal insulation materials, samples 17 and 18, consisting of long sheet-like molded bodies, were prepared in the same manner as in Example 1, except that titanium dioxide (average particle size 2 μm) and zirconium silicate (average particle size 2 μm) were used as infrared scattering materials instead of silicon carbide. The thermal insulation material of sample 17 obtained had good winding properties and a bulk density of 320 kg / m². 3 The deflection was 17.2 mm, the compressive strength was 7.8 MPa, the thermal conductivity was 0.03 W / (m·K), and the heat resistance temperature was 1000°C. On the other hand, the insulation material of sample 18 had good winding properties and a bulk density of 320 kg / m 3 The deflection was 16.2 mm, the compressive strength was 7.9 MPa, the thermal conductivity was 0.04 W / (m·K), and the heat resistance temperature was 1000°C.

[0048] [Example 8] To investigate the effect of changing the materials of inorganic fine particles, refractory fibers, and infrared scattering material on the properties of the thermal insulation material, a thermal insulation material sample 19 was prepared in the same manner as in Example 1, except that alumina fine particles (average particle size 0.2 μm) were used instead of silicate fine particles for the inorganic fine particles, alumina fibers (average fiber diameter 5 μm) were used instead of glass filament fibers for the refractory fibers, and zirconium silicate (average particle size 2 μm) was used instead of silicon carbide for the infrared scattering material. The thermal insulation material of sample 19 obtained had good windability and a bulk density of 340 kg / m². 3 The deflection was 16.5 mm, the compressive strength was 6.8 MPa, the thermal conductivity was 0.05 W / (m·K), and the heat resistance temperature was 1200°C.

[0049] [Example 9] To investigate the effect of the resin binder material on the properties of the thermal insulation material, thermal insulation materials consisting of long sheet-like molded bodies, samples 20-22, were prepared in the same manner as in Example 1, except that polyethylene powder, polyvinyl alcohol fibers (fiber diameter 0.15 dtex, fiber length 5 mm), and polyethylene fibers (fiber diameter 0.15 dtex, fiber length 5 mm) were used as the resin binder instead of polyethylene / polypropylene core-sheath structure fibers.

[0050] The obtained sample 20 insulation material had good winding properties and a bulk density of 320 kg / m². 3 The deflection was 15.1 mm, the compressive strength was 4.9 MPa, the thermal conductivity was 0.03 W / (m·K), and the heat resistance temperature was 1000°C. The insulation material of sample 21 had good winding properties and a bulk density of 310 kg / m 3 The material exhibited a deflection of 17.3 mm, a compressive strength of 6.8 MPa, a thermal conductivity of 0.03 W / (m·K), and a heat resistance temperature of 1000°C. The insulation material of sample 22 had good winding properties and a bulk density of 310 kg / m². 3 The deflection was 18.3 mm, the compressive strength was 6.2 MPa, the thermal conductivity was 0.03 W / (m·K), and the heat resistance temperature was 1000°C.

[0051] [Example 10] To investigate the effect of using two different materials for each component of the thermal insulation material on its properties, a thermal insulation material sample 23, consisting of a long sheet-shaped molded body, was prepared in the same manner as in Example 1, except that alumina fibers were added to the glass long fibers of the fire-resistant fiber to create multiple types. A thermal insulation material sample 24, consisting of a long sheet-shaped molded body, was also prepared in the same manner as in Example 1, except that alumina fine particles were added to the silica fine particles of the inorganic fine particles to create multiple types. Furthermore, a thermal insulation material sample 25, consisting of a long sheet-shaped molded body, was prepared in the same manner as in Example 1, except that titanium dioxide was added to the silicon carbide of the infrared scattering material to create multiple types.

[0052] The obtained sample 23 insulation material had good winding properties and a bulk density of 300 kg / m². 3 The material exhibited a deflection of 16.4 mm, a compressive strength of 6.3 MPa, a thermal conductivity of 0.03 W / (m·K), and a heat resistance temperature of 1000°C. The insulation material of sample 24 had good winding properties and a bulk density of 320 kg / m². 3 The material exhibited a deflection of 15.8 mm, a compressive strength of 6.5 MPa, a thermal conductivity of 0.04 W / (m·K), and a heat resistance temperature of 1000°C. The insulation material of sample 25 had good winding properties and a bulk density of 310 kg / m². 3 The deflection was 17.1 mm, the compressive strength was 6.2 MPa, the thermal conductivity was 0.03 W / (m·K), and the heat resistance temperature was 1000°C.

[0053] Tables 1 and 2 below summarize the mixing ratios, physical properties, and morphology of each thermal insulation material sample from Examples 1 to 10 described above.

[0054] [Table 1]

[0055] [Table 2]

[0056] [Comparative Example 1] The raw material mixture prepared in the same manner as in Example 1 had a bulk density of 300 kg / m³. 3 Comparative Example 1, a sheet-like molded body, was produced by placing the material in a mold and dry-compressing it without heating. When evaluating the winding properties of this Comparative Example 1, fracture occurred. It had a deflection of 3.2 mm, a compressive strength of 5.5 MPa, a thermal conductivity of 0.05 W / (m·K), and a heat resistance temperature of 1000°C.

[0057] [Comparative Example 2] A raw material mixture prepared in the same manner as sample 5 of Example 3, with a bulk density of 250 kg / m³ 3 Comparative Example 2, a sheet-like molded body, was produced by placing the material in a mold and dry-compressing it without heating. When evaluating the winding properties of this Comparative Example 2, fracture occurred. It had a deflection of 2.7 mm, a compressive strength of 4.9 MPa, a thermal conductivity of 0.04 W / (m·K), and a heat resistance temperature of 1000°C.

[0058] Table 3 below summarizes the mixing ratios and physical properties / morphology of Comparative Examples 1 and 2 described above.

[0059] [Table 3] [Explanation of Symbols]

[0060] 1 Inorganic fine particles 2. Fire-resistant fiber 3. Infrared scattering material 4. Resin Binder 11 chambers 11a Raw material supply port 11b Air outlet 11c Gas exhaust port 12 Mesh Conveyor 13. Pressure press machine 14 Insulation Roll

Claims

1. A bulk density of 200 kg / m³ is achieved by mixing inorganic fine particles made of metal oxide as the main material, fire-resistant fibers, infrared scattering material, and a fused resin binder. ３ More than 500kg / m ３ An insulating material comprising the following sheet-like molded body, wherein the fire-resistant fibers are randomly oriented in a direction substantially perpendicular to the thickness direction of the molded body.

2. The thermal insulation material according to claim 1, wherein the resin binder is an organic fiber.

3. The thermal insulation material according to claim 1, wherein the heat resistance temperature is 1000°C or higher and 1200°C or lower, and the thermal conductivity at 600°C is 0.05 W / (m·K) or less.

4. The thermal insulation material according to any one of claims 1 to 3, wherein the molded body is in the form of a long sheet and is wound into a roll.

5. A method for manufacturing a heat insulating material by a dry process, comprising: a deposition step of dispersing and depositing a mixture of inorganic fine particles made of metal oxide as the main material, fire-resistant fibers, an infrared scattering material, and a resin binder in a horizontally flowing airflow; and a molding step of heat-compressing the obtained deposition into a sheet shape, thereby thermally fusing the resin binder to at least the inorganic fine particles.

6. The method for manufacturing an insulating material according to claim 5, wherein the long sheet-like insulating material manufactured by continuously performing the deposition step and the molding step is wound into a roll.

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