JP2019078337A - Heat insulation material and manufacturing method thereof - Google Patents

Abstract

To provide a heat insulation material having heat resistance under a high temperature and an excellent heat insulation property and having a high mechanical strength.SOLUTION: The present invention relates to a sintered body containing a porous heat insulation aggregate in 10 to 40 mass% consisting of a high heatproof composition whose heatproof temperature is 1200°C or higher and including pores whose pore diameter ranges from 500 to 1000 nm, preferably, containing a fireproof fiber in 10 to 30 mass% as a reinforcement material consisting of a high heatproof composition whose heatproof temperature is 1400°C or higher, containing an inorganic filler in 40-60 mass% consisting of metal oxide particles whose average particle diameter is 100 nm or less, and containing an infrared ray scattering material in 8 to 20 mass%. Pores whose pore diameter ranges from 100 to 2000 nm occupy 30% or more and 60% or less of volume of all the pores. Thus, heat conductivity at 1200°C is 0.12 W/(m K) or less, a flexure strength is 0.5 MPa or more and a heater wire shrinkage wire after heating at 1400°C for 24 hours is 4% or less.SELECTED DRAWING: None

Description

  The present invention relates to a heat insulating material having high heat insulation and heat resistance under high temperature, and further having high mechanical strength, and a method of manufacturing the same.

  Insulating materials used in industrial facilities such as industrial furnaces that are treated at high temperatures have not only high thermal insulation from the viewpoint of energy saving, but also excellent heat resistance at high temperatures and higher mechanical properties. It is required to have strength. For example, the heat insulating material of the heat treatment furnace is required to have heat resistance and high strength at a maximum use temperature of 1400 ° C. With regard to heat insulation, in order to suppress energy loss as much as possible, it is required to have a thermal conductivity similar to or less than the thermal conductivity of air.

  As a heat insulating material used for the above-mentioned industrial equipment, the heat insulating material which uses inorganic fiber as a base material conventionally has been used. For example, Patent Document 1 discloses a heat insulating material of an inorganic fiber manufactured by adding an inorganic binder such as silica sol and a coagulant to an inorganic fiber such as a silica-alumina fiber from which non-fiber particles have been removed, and dehydrating it. Is disclosed. This heat insulating material can be used at high temperatures up to 1400 ° C and has high strength, but for heat insulation, thermal conductivity at 1000 ° C is 0.15 W / (m · K), thermal conductivity at 1200 ° C The rate was 0.17 W / (m · K). The thermal conductivity of air is 0.08 W / (m · K) at 1000 ° C and 0.09 W / (m · K) at 1200 ° C. The thermal conductivity was about 2.0 times greater than that of air, and it could not be said that it had satisfactory heat insulation performance.

  A low thermal conductivity material called a microporous thermal insulation material is known as a thermal insulation material having a thermal conductivity lower than that of the above-mentioned inorganic fibrous thermal insulation material. For example, in patent document 2, the convection heat transfer of gas is suppressed by reducing the pore size between particles using fine particle silica of nano-class particle diameter, and inorganic fiber is mixed for reinforcement, and compression molding is performed. Thermal insulation is disclosed. This thermal insulation material is designed to obtain the maximum thermal insulation performance by making a fine porous structure, for example, the thermal conductivity of 800 ° C. is 0.05 W / (m · K), and the same temperature Since the thermal conductivity of air in the above is smaller than 0.07 W / (m · K), it has excellent thermal insulation performance.

  Further, it has been proposed to reduce the thermal conductivity and to improve the heat resistance by using, as a raw material of the heat insulating material, nano-class alumina particles having higher heat resistance than silica. For example, Patent Document 3 discloses a heat insulating material having heat resistance up to a maximum use temperature of 1200 ° C. and having a thermal conductivity of 0.07 W / (m · K) at 1000 ° C. This heat insulating material has excellent heat insulating performance since it has a heat conductivity smaller than the heat conductivity of air 0.08 W / (m · K) at the same temperature. Furthermore, Patent Document 4 discloses a heat insulating material having a maximum use temperature of 1400 ° C. and a thermal conductivity of 0.09 W / (m · K) at 1000 ° C., which are fired at 1400 ° C.

JP 2014-228035 A Patent No. 5683739 gazette Unexamined-Japanese-Patent No. 2016-40226 JP, 2016-173178, A

  However, the microporous heat insulating material as disclosed in Patent Document 3 has only heat resistance up to a maximum use temperature of 1200 ° C. because the nano class particles sinter and shrink. The heat insulating material of Patent Document 4 has a heat resistance of 1400 ° C., and although the thermal conductivity at 1000 ° C. indicates 0.09 W / (m · K) in the example, it has a low thermal conductivity due to the fine porous structure. Since it is necessary to realize metal oxide particles such as alumina and mullite having a particle size of nano class in liquid nitrogen and freeze-drying it, aggregates with pores are produced. Production is likely to be expensive.

  The present invention has been made in view of the above-mentioned problems with the conventional heat insulating material, and a heat insulating material having heat resistance up to a maximum use temperature of 1400 ° C. and having desired heat insulating properties and high strength is industrially The purpose is to provide at low cost.

  In order to achieve the above object, the heat insulating material according to the present invention is composed of a high heat resistant composition having a heat resistant temperature of 1200 ° C. or higher and 10 to 40 mass of a porous heat insulating aggregate having pores with a pore diameter of 500 to 1000 nm. %, Containing 10 to 30% by mass of refractory fibers, 40 to 60% by mass of an inorganic filler consisting of metal oxide particles having an average particle diameter of 100 nm or less, and 8 to 20% by mass of an infrared scattering material The sintered body is characterized in that pores with a diameter of 100 to 2000 nm occupy 30% or more and 60% or less of the volume of all the pores.

  According to the present invention, a heat insulating material having desired heat insulating performance and high strength and having heat resistance up to a maximum use temperature of 1400 ° C. can be industrially produced inexpensively.

  It is preferable that the heat insulating material used for heat insulation of industrial facilities, such as an industrial furnace in which treatment at high temperature is performed, has a heat conductivity similar to or less than the heat conductivity of air. The thermal conductivity of air is, for example, 0.08 W / (m · K) at 1000 ° C. and 0.09 W / (m · K) at 1200 ° C. In such a high temperature range of 1000 to 1200 ° C., the thermal conductivity is greatly influenced by convective heat transfer and radiation heat transfer. Among these, convective heat transfer can be suppressed by making the pores of the heat insulating material smaller than the mean free path of air.

  The mean free path of air is proportional to temperature, 273 nm at 1000 ° C., 316 nm at 1200 ° C. and 359 nm at 1400 ° C. It is desirable to make the pores of the thermal insulation smaller than these. In order to form such pores, a method of reducing the void size between particles using nano-sized metal oxide particles such as silica, alumina, mullite or the like, or a raw material is put into liquid nitrogen and freeze-dried There is a method of producing the aggregate which has a pore by doing.

  On the other hand, in order to reduce the radiation heat transfer, it is possible to increase the number of single micron-sized pores, which are about the same size as the light wavelength, or to include many particles having a single micron-sized particle size. There is a way to enhance the light scattering effect. In particular, it is desirable to include particles having an average particle size similar to the wavelength of the infrared radiation that brings about heat transfer, preferably an average particle size about half that wavelength. Specifically, for example, the peak wavelength at a temperature of 100 to 1000 ° C. is approximately 2 to 8 μm (2000 to 8000 nm). If it is 1 to 4 μm (1000 to 4000 nm) corresponding to about half of the peak wavelength, radiation heat transfer at 100 to 1000 ° C. can be effectively suppressed by Mie scattering.

  In addition, the mechanical strength of the heat insulating material is evaluated by the bending strength, and by making the bending strength larger than 0.5 MPa, excellent dimensional stability and shape stability are obtained even under conditions where temperature rising and temperature lowering are repeated. It is possible to maintain the properties and further to make the material resistant to breakage during construction and processing, as well as to have strength that resists breakage and wear of ridges.

  As a result of earnestly researching based on the above-mentioned findings, the inorganic filler which consists of the heat insulation aggregate of the porous structure which has a pore with a pore diameter of 500-1000 nm, the fireproof fiber as a reinforcing material, and metal oxide particles of nano size. And, by constructing a porous sintered body with an infrared scattering material, it is found that a heat insulating material having high heat insulation and heat resistance under high temperature, and further having high mechanical strength can be provided at low cost. The present invention has been completed. Hereinafter, an embodiment of the heat insulating material of the present invention having the above-described features will be specifically described for each component. In the following description, unless otherwise specified, the pore size is measured by a mercury porosimeter, and the average particle size is a volume-based 50% diameter (D50) measured by a laser diffraction particle size distribution analyzer. .

  The porous heat insulating aggregate of the heat insulating material according to the embodiment of the present invention comprises a high heat resistant composition having a heat resistant temperature (also referred to as a maximum use temperature) of 1200 ° C. or higher and a pore having a pore diameter of 500 to 1000 nm. Use thermal insulation aggregate of quality structure. Also, for example, when the maximum use temperature of the heat insulating material is 1200 ° C., the heat insulating aggregate having a heat resistant temperature of 1200 ° C. or higher is used, and when the maximum use temperature of the heat insulating material is 1400 ° C. Use those of 1400 ° C. or higher. The heat resistance temperature 1400 ° C refers to the case where the heating linear shrinkage percentage is 4% or less when heated at an atmosphere temperature 1400 ° C for 24 hours, and the heat resistance temperature 1200 ° C is a heat when heated at an atmosphere temperature 1200 ° C for 24 hours When the linear shrinkage rate is 4% or less.

Such insulation aggregates, but are not limited to, heat-resistant temperature 1400 ° C. or more insulation aggregate in example spinel ceramics (Coors Tech Co., Ltd. of Thermoscatt (registered trademark)) and, CaO · _6Al 2 O ₃ (Calcia aluminate) ceramics (SLA-92 manufactured by Almatis, Inc.) etc. can be mentioned, For example, porous alumina can be mentioned by the heat insulation aggregate whose heat-resistant temperature is 1200 degreeC or more.

It is preferable that the fire resistant fiber as a reinforcing material which the heat insulating material of embodiment of this invention has uses the fiber which consists of a highly heat-resistant composition 1400 degreeC or more. Such fire resistant fibers may include, but are not limited to, alumina fibers, mullite fibers, CaO · 6Al ₂ O ₃ (calcia aluminate) fibers, zirconia fibers, and biosoluble fibers, for example. It is preferable to use one or more selected from the group consisting of these fibers. All of these fire resistant fibers have no possibility of carcinogenicity and are preferable in that they are not specified as specific chemical substances. Among these, mullite fibers (for example, fiber max 1600 manufactured by ITM Co., Ltd.) or aluminous fibers are preferable. The refractory fiber preferably has an average fiber diameter of 1 μm to 10 μm, and more preferably 2 μm to 6 μm. In addition, with said average fiber diameter, the fiber group of measurement object is image | photographed with an electron microscope, the distance of the width direction of 200 or more fibers arbitrarily selected from the obtained image is measured, and these are calculated. It is an average.

  The inorganic filler of the heat insulating material according to the embodiment of the present invention uses nano-sized fine particles of metal oxide having heat resistance at high temperature. As a result, the size of the gap between the particles of the porous heat insulating aggregate, the refractory fiber and the infrared scattering material can be reduced, and the convection heat transfer of the gas at high temperature can be suppressed. Here, nano-sized particles mean particles having an average particle diameter of 1 nm or more and 100 nm or less. Examples of the above metal oxides include, but are not limited to, alumina, magnesia, mullite, and zirconia, and it is preferable to use one or more selected from the group consisting of these metal oxides. . Among these, alumina, mullite or zirconia is preferred.

  The infrared scattering material included in the heat insulating material according to the embodiment of the present invention is not particularly limited as long as it is made of a composition having a heat resistance temperature of 1000 ° C. or higher capable of reducing heat transfer due to radiation. Is preferred. Examples of such a composition include zirconium silicate, zirconia, and alumina, and it is preferable to use one or more selected from the group consisting of these compositions. The above-mentioned infrared scattering material preferably has an average particle diameter of 100 nm or more and 5000 nm or less, and in particular, the upper limit is 2000 nm or less, which is the same as the average particle diameter of the peak wavelength of 1200 ° C. Is more preferred.

  In the heat insulating material according to the embodiment of the present invention, when the content of the porous heat insulating aggregate is too small, the volume of all the pores of the heat insulating material is reduced, so that the heat transfer is increased. Becomes large and the heat insulation is reduced. Conversely, if the content of the porous heat insulating aggregate is too large, the strength of the heat insulating material decreases. If the content of the refractory fiber is too small, the strength decreases, and conversely, if the content of the refractory fiber is too large, pores larger than the pores effective for suppressing radiation increase, so that the radiation increases. As a result, the thermal conductivity is increased and the heat insulation is reduced. If the content of the inorganic filler is too small, the strength decreases, and conversely, if the content of the inorganic filler is too large, the volume of all the pores of the heat insulating material decreases and the conductive heat transfer increases. As a result, the thermal conductivity is increased and the heat insulation is reduced. When the content of the infrared scattering material is too small, the radiation suppressing effect is reduced, the thermal conductivity is increased, and the heat insulation is reduced. Conversely, if the content of the infrared scattering material is too large, the strength of the heat insulating material is reduced.

  In consideration of the above, the content of each of the above-described components constituting the heat insulating material of the embodiment of the present invention can be appropriately adjusted so as to obtain desired properties of the heat insulating material. Specifically, the content of each component described above constituting the heat insulating material according to the embodiment of the present invention is 10 to 40% by mass in the porous heat insulation aggregate, and 10 to 30% by mass in the fireproof fiber In the case of the inorganic filler, the content is 40 to 60% by mass, and the content of the infrared scattering material is 8 to 20% by mass. Furthermore, the heat insulating material according to the embodiment of the present invention preferably contains 98% by mass or more in total of the above-mentioned porous heat insulating aggregate, fire resistant fiber, inorganic filler, and infrared ray scattering material. May be included.

  The heat insulating material according to the embodiment of the present invention is produced by dry-mixing the above-described raw materials having the heat insulating aggregate, the fire resistant fiber, the inorganic filler, and the infrared scattering material by a known method and then pressing it by a known method. can do. For example, although not limiting, a step of dry-mixing the above-mentioned raw materials with a high-speed mixer (for example, a rhage mixer, a Henschel mixer, etc.), and filling the obtained mixture in a predetermined molding die to dry press molding A molded body can be produced by the following steps.

The obtained molded body becomes a heat insulating material by performing a sintering process to prevent heat shrinkage and develop strength. There are no particular limitations on the sintering conditions in this case, but in the case of producing a heat insulating material with a maximum use temperature of 1400 ° C., the surface temperature of the molded body is a porous heat insulation aggregate with a heat resistant temperature of 1400 ° C. or higher. It is preferable to hold for about 1 hour under the temperature condition of 1400 ° C. In the case of producing a heat insulating material having a maximum use temperature of 1200 ° C. by sintering the same formed body, a temperature at which the surface temperature of the formed body becomes 1200 ° C. using a porous heat insulation aggregate having a heat resistant temperature of 1200 ° C. or more It is preferable to hold for about 1 hour under the conditions. In addition, you may change holding time suitably by the thickness of the molded object at the time of sintering.

  The heat insulating material obtained by the above-mentioned sintering treatment is such that pores with a pore diameter of 100 to 2000 nm become 30% or more and 60% or less of the volume of all the pores. If this value is less than 30%, it is difficult to obtain the radiation suppression effect, and a desired low thermal conductivity can not be obtained. On the other hand, if this value exceeds 60%, there may be a problem of strength. In addition, what is necessary is just to set the pressure at the time of pressure molding low, when the volume ratio with respect to all the pores of 100-2000 nm of said pore diameter is less than 30%, conversely, at the time of pressure molding when exceeding 60% The pressure may be set higher.

  The heat insulating material obtained by producing by the said method using said raw material can make the heat conductivity in 1200 degreeC 0.12 W / (m * K) or less. When the requirement of the thermal conductivity is not satisfied, the blending ratio of the molded body may be changed appropriately. For example, the content of the heat insulating aggregate or the infrared scattering material may be increased or the content of the fireproof fiber or the inorganic filler may be reduced as long as the strength does not become too low. Alternatively, the pressure during pressure molding may be set lower.

  In the case of using a porous heat insulating aggregate having a heat resistant temperature of 1400 ° C. or higher, the heat linear shrinkage when reheated under the heat treatment condition of an atmosphere temperature of 1400 ° C. for 24 hours is 4% or less. The maximum operating temperature can be 1400 ° C. In addition, when a porous heat insulating aggregate having a heat resistant temperature of 1200 ° C. or higher is used, the heating linear shrinkage when reheated under the heat treatment condition of an atmosphere temperature of 1200 ° C. for 24 hours is 4% or less The maximum operating temperature of the heat insulating material can be 1200 ° C. The thermal conductivity at 1200 ° C. is measured by the test method according to the flat plate comparison method (JIS A 1412-2 Annex A), and the heating linear shrinkage is measured by the test method according to ASTM C356. is there.

  Moreover, the thermal insulation obtained by the said method using said raw material becomes larger than 0.5 MPa or more in bending strength. If the bending strength is less than 0.5 MPa, it is not preferable because it is easily damaged during handling or processing. In addition, what is necessary is just to change the compounding ratio of a molded object suitably, when not satisfy | filling the requirements of bending strength. For example, the content of the heat insulating aggregate or the infrared scattering material may be reduced or the content of the fireproof fiber or the inorganic filler may be increased as long as the thermal conductivity does not become too high. Alternatively, the pressure during pressure molding may be set high. In addition, said bending strength and compressive strength as a reference are each measured by the following method.

(1) Bending strength A test piece is cut into a length of 150 mm, a width of 50 mm, and a thickness of 25 mm, and a 3-point bending test is performed using an autograph at a distance of 100 mm between fulcrums. Calculated.
(2) Compressive strength A test piece was cut into a length of 100 mm, a width of 100 mm, and a thickness of 25 mm, a compression test was performed using an autograph, and the maximum load up to 10% strain was calculated.

Example 1
As a raw material, a heat insulation aggregate, a fireproof fiber, an inorganic filler, and an infrared scattering material were prepared, and a molding obtained by mixing and molding these was sintered to form a heat insulation material, and the characteristics were evaluated. Specifically, for the porous heat-insulating aggregate, spinel-based ceramics (Thermoscatt (registered trademark), average particle diameter 8000 nm) manufactured by QUARSTECH CORPORATION was used. The porous heat insulating aggregate had a porosity of 85 to 91% by volume measured according to JIS R 2614, and had pores with a pore diameter of 500 to 1000 nm. As the heat-resistant fiber, mullite fiber (Fiber Max 1600 special product manufactured by ITM, average fiber diameter 4 μm, shot content rate 0.5 mass%) was used.

As the inorganic filler, nano-sized alumina (SpectrAl (registered trademark) 100 manufactured by Cabot Japan Ltd., specific surface area measured by BET method: 95 to 100 m ² / g, average particle diameter: about 18 nm) was used. As the infrared scattering material, zirconium silicate (A-PAX average particle diameter (D50) 1.0 μm, manufactured by Kinseimatech Co., Ltd., relative refractive index 1.9) was used. These four types of raw materials were compounded at a ratio of 10% by mass of heat insulation aggregate, 22% by mass of fireproof fiber, 60% by mass of inorganic filler, and 8% by mass of infrared scattering material, and charged into a Ladeige mixer and mixed . The resulting mixture was divided into five parts, each of which was charged into a dry press and pressed at different pressures to prepare five types of molded bodies.

  The five types of molded bodies were subjected to a baking treatment by being held at an atmosphere temperature of 1400 ° C. for one hour to produce a heat insulating material of Samples 1 to 5. The volume and distribution of the pore diameter of the heat insulating material of samples 1 to 5 thus obtained were measured with a mercury porosimeter. As a result, the volume ratio of pores having a pore diameter of 100 to 2000 nm with respect to the total pore volume is 28% by volume in sample 1, 30% by volume in sample 2, 50% by volume in sample 3, and 60 in sample 4. For the volume%, sample 5 was 61 volume%. The thermal conductivity at 1200 ° C. is 0.13 W / (m · K) for sample 1, 0.12 W / (m · K) for sample 2, 0.09 W / (m · K) for sample 3, In the sample 4, it was 0.09 W / (m · K), and in the sample 5, it was 0.09 W / (m · K).

  Furthermore, when the flexural strength and the compressive strength and the heating linear shrinkage at 1400 ° C. were measured by the above-mentioned method, the sample 2 had a flexural strength of 1.1 MPa, a compressive strength of 1.2 MPa and a heating linear shrinkage of 2.8%. Sample 3 has a flexural strength of 0.6 MPa, a compressive strength of 0.8 MPa, a heating linear shrinkage of 3.0%, and a sample 4 has a flexural strength of 0.5 MPa, a compressive strength of 0.6 MPa, a heating line The shrinkage ratio was 3.4%, and the sample 5 had a flexural strength of 0.3 MPa and a compressive strength of 0.4 MPa.

Example 2
Except using CaO · 6Al ₂ O ₃ (calcia aluminate) ceramics (SL-92 manufactured by Almatis, average particle size 8000 nm) having pores with a pore diameter of 500 to 1000 nm as the heat insulating aggregate instead of spinel ceramics In the same manner as in the case of Sample 2 of Example 1 described above, a heat insulating material of Sample 6 in which the volume ratio of pores having a pore diameter of 100 to 2000 nm with respect to the total pore volume was 30% by volume was produced. The heat insulating material of the obtained sample 6 had a thermal conductivity of 0.12 W / (m · K), a bending strength of 1.0 MPa, a compressive strength of 1.2 MPa, and a heating linear shrinkage of 2.8%.

[Example 3]
The same as in the case of sample 2 of the above example except using alumina fiber (Maftec special product, average fiber diameter 4 μm, shot content 1.0%) instead of mullite fiber as fire resistant fiber A heat insulating material of sample 7 having a volume ratio of pores with a pore diameter of 100 to 2000 nm to the total pore volume of 30% by volume was produced. The heat insulating material of the obtained sample 7 had a thermal conductivity of 0.12 W / (m · K), a bending strength of 1.0 MPa, a compressive strength of 1.2 MPa, and a heating linear shrinkage of 2.8%.

Example 4
A pore diameter of 100 to the total pore volume is the same as in the case of the sample 2 of the above Example 1 except that nano-sized magnesia (manufactured by Ion Ceramics Co., Ltd., particle size about 90 nm) is used instead of nano-sized alumina as an inorganic filler. A heat insulating material of sample 8 having a volume fraction of pores of 2000 nm of 30% by volume was produced. The obtained heat insulating material of sample 8 had a thermal conductivity of 0.12 W / (m · K), a bending strength of 1.0 MPa, a compressive strength of 1.2 MPa, and a heating linear shrinkage of 2.6%.

[Example 5]
The sample of Example 1 was used except that plate-like alumina (Model No. 00610, average particle diameter (D50) 0.5 μm, relative refractive index 1.7) made by Kinseimatech Co., Ltd. was used instead of zirconium silicate as the infrared scattering material. In the same manner as in the case of 2, a heat insulating material of sample 9 having a volume ratio of pores with a pore diameter of 100 to 2000 nm to the total pore volume of 30% by volume was produced. The obtained heat insulating material of sample 9 had a thermal conductivity of 0.12 W / (m · K), a bending strength of 1.0 MPa, a compressive strength of 1.2 MPa, and a heating linear shrinkage of 2.6%.

[Example 6]
The same as in the case of the sample 2 of the above-mentioned Example 1 except that a mixture of nano-sized alumina and the nano-sized magnesia used in Example 4 mixed at a mixing ratio of 1 to 1 as an inorganic filler was used. A heat insulating material of sample 10 having a volume ratio of pores with a pore diameter of 100 to 2000 nm to the total pore volume of 30% by volume was produced. The obtained heat insulating material of sample 10 had a thermal conductivity of 0.12 W / (m · K), a bending strength of 1.1 MPa, a compressive strength of 1.2 MPa, and a heating linear shrinkage of 2.6%.

[Example 7]
The total pore volume is the same as in the case of the sample 2 of the above-mentioned Example 1 except that a mixture of zirconium silicate and alumina used in Example 5 in a mixing ratio of 1 to 1 is used as an infrared scattering material. A heat insulating material of sample 11 having a volume fraction of pores with a pore diameter of 100 to 2000 nm relative to 30% by volume was produced. The heat insulating material of the obtained sample 11 had a thermal conductivity of 0.12 W / (m · K), a bending strength of 1.1 MPa, a compressive strength of 1.2 MPa, and a heating linear shrinkage of 2.6%.

[Example 8]
The total pore volume is the same as in the case of sample 2 of Example 1 except that the blending ratio is set to 40 mass% of heat insulation aggregate, 10 mass% of fire resistant fiber, 40 mass% of inorganic filler, and 10 mass% of infrared scattering material. A heat insulating material of sample 12 having a volume fraction of pores with a pore diameter of 100 to 2000 nm of 30% by volume was produced. The heat insulating material of the obtained sample 12 had a thermal conductivity of 0.12 W / (m · K), a bending strength of 0.6 MPa, a compressive strength of 0.7 MPa, and a heating linear shrinkage of 2.3%.

[Example 9]
The total pore volume is the same as in the case of the sample 2 of the example 1 except that the blending ratio is 10 mass% of heat insulation aggregate, 30 mass% of fireproof fiber, 52 mass% of inorganic filler, and 8 mass% of infrared scattering material. A heat insulating material of sample 13 having a volume fraction of pores with a pore diameter of 100 to 2000 nm of 30% by volume was produced. The heat insulating material of the obtained sample 13 had a thermal conductivity of 0.12 W / (m · K), a bending strength of 0.9 MPa, a compressive strength of 1.0 MPa, and a heating linear shrinkage of 2.4%.

[Example 10]
The total pore volume is the same as in the case of sample 2 of Example 1 except that the blending ratio is 10 mass% of heat insulation aggregate, 22 mass% of fireproof fiber, 48 mass% of inorganic filler, and 20 mass% of infrared scattering material. The heat insulating material of the sample 14 of 30 volume% of the volume ratio of the pore of 100-2000 nm of pore diameters was produced. The heat insulating material of the obtained sample 14 had a thermal conductivity of 0.12 W / (m · K), a bending strength of 0.8 MPa, a compressive strength of 1.0 MPa, and a heating linear shrinkage of 2.6%.

Comparative Example 1
The total pore volume is the same as in the case of sample 2 of Example 1 except that the blending ratio is 42 mass% of heat insulation aggregate, 10 mass% of fire resistant fiber, 40 mass% of inorganic filler, and 8 mass% of infrared scattering material. The heat insulating material of the sample 15 of 30 volume% of volume ratio of the pore of 100-2000 nm of pore diameters was produced. The heat insulator of the obtained sample 15 had a thermal conductivity of 0.14 W / (m · K).

Comparative Example 2
The total pore volume is the same as in the case of the sample 2 of the example 1 except that the blending ratio is 9 mass% of heat insulation aggregate, 23 mass% of fireproof fiber, 60 mass% of inorganic filler, and 8 mass% of infrared scattering material. The heat insulating material of the sample 16 of 30 volume% of volume ratio of the pore with a hole diameter of 100-2000 nm was produced. The thermal insulation of the obtained sample 16 had a thermal conductivity of 0.14 W / (m · K).

Comparative Example 3
The total pore volume is the same as in the case of the sample 2 of Example 1 except that the blending ratio is 10 mass% of heat insulation aggregate, 31 mass% of fireproof fiber, 51 mass% of inorganic filler, and 8 mass% of infrared scattering material. The heat insulating material of the sample 17 of 30 volume% of the volume ratio of the pore with a hole diameter of 100-2000 nm was produced. The heat insulator of the obtained sample 17 had a thermal conductivity of 0.14 W / (m · K).

Comparative Example 4
The total pore volume is the same as in the case of sample 2 of Example 1 except that the blending ratio is 23 mass% of heat insulation aggregate, 9 mass% of fireproof fiber, 60 mass% of inorganic filler, and 8 mass% of infrared scattering material. A heat insulating material of sample 18 having a volume fraction of pores with a pore diameter of 100 to 2000 nm of 30% by volume was produced. The obtained heat insulating material of sample 18 had a bending strength of 0.4 MPa and a compressive strength of 0.5 MPa.

Comparative Example 5
The total pore volume is the same as in the case of sample 2 of Example 1 except that the blending ratio is 10 mass% of heat insulation aggregate, 21 mass% of fireproof fiber, 61 mass% of inorganic filler, and 8 mass% of infrared scattering material. A heat insulating material of sample 19 having a volume fraction of pores with a pore diameter of 100 to 2000 nm of 30% by volume was produced. The thermal insulation of the obtained sample 19 had a thermal conductivity of 0.14 W / (m · K).

Comparative Example 6
The total pore volume was the same as in the case of sample 2 of Example 1 except that the blending ratio was changed to 30% by mass of heat insulation aggregate, 24% by mass of refractory fiber, 38% by mass of inorganic filler, and 8% by mass of infrared scattering material. A heat insulating material of sample 20 having a volume fraction of pores with a pore diameter of 100 to 2000 nm of 30% by volume was produced. The heat insulating material of the obtained sample 20 had a thermal conductivity of 0.14 W / (m · K).

Comparative Example 7
The total pore volume was the same as in the case of sample 2 of Example 1 except that the blending ratio was changed to 10% by mass of heat insulation aggregate, 23% by mass of fireproof fiber, 60% by mass of inorganic filler, and 7% by mass of infrared scattering material. A heat insulating material of sample 21 having a volume fraction of pores with a pore diameter of 100 to 2000 nm of 30% by volume was produced. The thermal insulation of the obtained sample 21 had a thermal conductivity of 0.14 W / (m · K).

Comparative Example 8
The total pore volume is the same as in the case of the sample 2 of Example 1 except that the blending ratio is 10 mass% of heat insulation aggregate, 22 mass% of fireproof fiber, 46 mass% of inorganic filler, and 22 mass% of infrared scattering material. A heat insulating material of sample 22 having a volume fraction of pores with a pore diameter of 100 to 2000 nm of 30% by volume was produced. The heat insulator of the obtained sample 22 had a thermal conductivity of 0.14 W / (m · K). The mixing ratios of the raw materials of the samples 1 to 22 and the evaluation results are summarized in Table 1 below.

  From the results in Table 1 above, the thermal insulator satisfying the requirements of the present invention has a thermal conductivity of 1200 ° C. of not more than 0.12 W / (m · K), and a bending strength of not less than 0.5 MPa that can be handled It was found that the heating linear shrinkage at 1400 ° C. was 4% or less. On the other hand, the heat insulating material which does not satisfy the requirements of the present invention did not obtain satisfactory results in any of the above-mentioned characteristics.

Claims (7)

  10 to 40% by mass of a porous heat insulating aggregate having a heat resistant temperature of 1200 ° C. or more and having a pore size of 500 to 1000 nm and containing 10 to 30% by mass of a fire resistant fiber, A sintered body containing 40 to 60% by mass of an inorganic filler consisting of metal oxide particles having an average particle size of 100 nm or less and 8 to 20% by mass of an infrared scattering material, and all pores with a pore diameter of 100 to 2000 nm A heat insulating material characterized in that it occupies 30% or more and 60% or less of the volume of pores. The refractory fiber is composed of a highly heat-resistant composition at 1400 ° C. or higher, and is a group consisting of an alumina fiber, a mullite fiber, a CaO · 6Al ₂ O ₃ (calcia aluminate) fiber, a zirconia fiber, and a biosoluble fiber The heat insulating material according to claim 1, which is at least one selected from the group consisting of   The heat insulating material according to claim 1, wherein the inorganic filler is one or more selected from the group consisting of alumina, magnesia, mullite, and zirconia.   The heat insulating material according to any one of claims 1 to 3, wherein the infrared scattering material is one or more selected from the group consisting of zirconium silicate, zirconia, and alumina.   Thermal conductivity at 1200 ° C. is 0.12 W / (m · K) or less, bending strength is 0.5 MPa or more, and heating linear shrinkage when heated at 1400 ° C. for 24 hours is 4% or less The heat insulation material of any one of Claims 1-4 characterized by these.   It is a manufacturing method of the heat insulating material of any one of Claims 1-5, Comprising: The mixing process of carrying out the dry mixing of the said heat insulation aggregate, the said fireproof fiber, the said inorganic filler, and the said infrared rays scattering material, The manufacturing method of the heat insulating material which has the formation process of pressure-molding the obtained mixture, and the sintering process of sintering the obtained said pressure forming body. The method of manufacturing a heat insulating material according to claim 6, characterized in that sintering is performed by heating so that the surface temperature of the pressure-formed body is 1200 ° C or more in the sintering step.