Geopolymer hardened body, heat insulation material, and composition for producing geopolymer

Abstract

To provide: a geopolymer hardened body of better heat insulation property; a heat insulation material comprising the geopolymer hardened body and having better heat insulation property; and a composition for producing a geopolymer, capable of yielding a geopolymer hardened body of better heat insulation property.SOLUTION: The geopolymer hardened body includes a geopolymer and aerogel, and has thermal conductivity of 100 mW / m-K or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hardened geopolymer, a thermal insulating material, and a composition for producing a geopolymer. [Background technology]

[0002] BACKGROUND ART Generally, heat insulating materials used in electronic components, moving bodies (vehicles, aircraft, etc.) and the like include heat insulating materials made of polyurethane foam (Patent Document 1), for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-124677 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, electronic components have become smaller and more functional, and mobile objects such as vehicles and aircraft have become more multifunctional. In response to this trend, there has been an increasing demand for heat insulating sheets, particularly those formed into thin sheets. There is a demand for heat insulating materials that have better heat insulating properties even when formed into sheets.

[0005] However, conventional heat insulating materials such as those disclosed in Patent Document 1 do not have sufficient heat insulating properties to cope with the above-mentioned changes. The problem to be solved by the present invention is to provide a material with better heat insulating properties. [Means for solving the problem]

[0006] The present inventors have conducted extensive research and discovered that a novel hardened geopolymer is useful as a thermal insulation material, and have found that the above-mentioned problems can be solved, leading to the completion of the present invention.

[0007] One aspect of the present invention is a hardened geopolymer material. The hardened geopolymer material contains a geopolymer and an aerogel and has a thermal conductivity of 100 mW / m·K or less.

[0008] Another aspect of the present invention is a thermal insulation material comprising the hardened geopolymer material of the above aspect.

[0009] Another aspect of the invention is a geopolymer-producing composition, comprising an aluminosilicate, an aerogel, an acidic activator, and water.

[0010] In the composition for producing geopolymer of the above aspect, the aerogel is preferably silica aerogel.

[0011] In the composition for producing a geopolymer of the above aspect, the content of the aerogel is preferably more than 0 mass%.

[0012] In the composition for producing geopolymer of the above aspect, it is preferable that a filler other than the aerogel is further contained. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide: a geopolymer hardened body having superior thermal insulation properties; and an insulating material having superior thermal insulation properties and comprising the geopolymer hardened body; and a geopolymer manufacturing composition from which a geopolymer hardened body having superior thermal insulation properties can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0014] In this specification, the expression "a to b" in the description of a range of values ​​means that the range is from a to b, unless otherwise specified.

[0015] In this specification, when multiple upper limit values ​​and multiple lower limit values ​​are separately described, all numerical ranges that can be set by freely combining these upper limit values ​​and lower limit values ​​are considered to be described in this specification.

[0016] In this specification, the term "particulate material" refers to an aggregate of "powder" or "particles."

[0017] The average particle size of the powder or particles {median particle size D50 (volume basis)} can be measured using a laser diffraction particle size distribution measuring device.

[0018] Unless otherwise specified, all measurements are performed at room temperature (25°C).

[0019] 1. Composition for producing geopolymer The geopolymer production composition of this embodiment includes an aluminosilicate, an aerogel, an acidic activator, and water. Preferably, the geopolymer production composition of this embodiment further includes a filler other than the aerogel.

[0020] By hardening the geopolymer production composition, a hardened geopolymer described below can be obtained. In other words, the geopolymer production composition is a precursor of the hardened geopolymer.

[0021] In this embodiment, an acidic activator is used as an activator for the geopolymer production composition, but an alkaline activator can also be used to obtain a hardened geopolymer, as described below. By using an acidic activator, a hardened geopolymer with superior mechanical properties and heat resistance can be obtained.

[0022] Geopolymers are amorphous polymers made primarily from aluminum, silicon, and other materials, and are obtained by reacting aluminosilicates and acidic activators, as described below.

[0023] The viscosity of the geopolymer production composition of this embodiment is preferably 5,000 mPa·s or more, 10,000 mPa·s or more, 15,000 mPa·s or more, and is preferably 50,000 mPa·s or less, 40,000 mPa·s or less, 35,000 mPa·s or less, etc. If the viscosity is within the above range, the aerogel is easily dispersed uniformly when the components of the geopolymer production composition of this embodiment are mixed.

[0024] The viscosity here is a B-type viscosity measured in accordance with JIS Z8803:2011 "Method for measuring viscosity of liquids." The viscosity is measured using a single cylindrical rotational viscometer (low viscosity spindle LV-4, rotation speed: 12 rpm).

[0025] Hereinafter, each component constituting the geopolymer production composition of this embodiment will be described in detail.

[0026] 1-1.Aluminosilicate The aluminosilicate of this embodiment (xM2O·yAl2O3·zSiO2·nH2O, where M is an alkali metal) is a compound having a structure in which some of the silicon atoms in a silicate are replaced with aluminum atoms.

[0027] 1-1-1.Ingredients Examples of the aluminosilicate of this embodiment include natural aluminosilicate minerals such as illite, stilbite, kaolinite, pyrophyllite, andalusite, bentonite, kyanite, milanite, glovenite, amesite, cordierite, feldspar, and allophane; calcined natural aluminosilicate minerals such as imogolite and metakaolin; fly ash obtained from coal combustion; and blast furnace slag obtained when iron ore is converted into cast iron in a blast furnace. Among these, calcined natural aluminosilicate minerals are preferred, with metakaolin being particularly preferred.

[0028] These substances can be commercially available and can be used alone or in combination of two or more. The aluminosilicate is used in the form of powder, and can be adjusted to an aluminosilicate of a desired particle size by appropriately grinding and classifying it and using a specific fraction.

[0029] Metakaolin, a particularly preferred aluminosilicate of this embodiment, is a compound represented by the chemical formula Al2O3·2SiO2. The metakaolin content relative to the total mass of the aluminosilicate is preferably 50 mass% or more, more preferably 60 mass% or more, even more preferably 80 mass% or more, and particularly preferably 90 mass% or more. When the metakaolin content relative to the total mass of the aluminosilicate is within the above range, a geopolymer hardened body with excellent strength can be consistently obtained.

[0030] 1-1-2.Physical properties / properties (Average particle size) The aluminosilicate powder of this embodiment preferably has an average particle size of 0.1 to 50 μm, more preferably 0.3 to 30 μm, and even more preferably 0.5 to 10 μm. When the average particle size of the powder is within this range, the heat insulating properties of the produced hardened geopolymer can be further improved.

[0031] 1-1-3.Content The content of the aluminosilicate in this embodiment is preferably 1% by mass or more, 5% by mass or more, 7% by mass or more, etc., based on the total mass of the geopolymer production composition, and is preferably 60% by mass or less, 55% by mass or less, 50% by mass or less, etc., based on the total mass of the geopolymer production composition. By setting the content of the aluminosilicate in the above range, it is easy to increase the strength of the geopolymer hardened body.

[0032] 1-2.Aerogel The aerogel of the present embodiment is not particularly limited, and examples thereof include low-density dry gels, etc. Specific examples include aerogels obtained using a supercritical fluid drying method, xerogels obtained by a normal drying process, and cryogels obtained by freeze-drying.

[0033] 1-2-1. Ingredients Any suitable aerogel component can be used as the aerogel of this embodiment. For example, it can be selected from inorganic aerogels such as silica aerogel and alumina aerogel, organic aerogels such as resorcinol-formaldehyde aerogel (RF aerogel) and cellulose nanofiber aerogel (CNF aerogel), carbon aerogels, and mixtures thereof. Among them, silica aerogel containing silica (SiO2) is preferred.

[0034] 1-2-2.Physical properties / properties (Average particle size) The average particle size of the aerogel of this embodiment is preferably 0.01 mm or more, 0.02 mm or more, 0.05 mm or more, 0.08 mm or more, etc., and is preferably 5.0 mm or less, 3.0 mm or less, 2.0 mm or less, 1.5 mm or less, etc. By setting the average particle size of the aerogel within the above range, a geopolymer hardened body with excellent thermal insulation properties can be obtained.

[0035] (pore diameter) The pore size of the aerogel of this embodiment is preferably 30 nm or less, more preferably 25 nm or less, and even more preferably 20 nm or less. Here, the "pore size" is a value measured using a pore size distribution analyzer (e.g., BELSORP MINI manufactured by Microtrack-Bell) in accordance with JIS Z8831-2 "Pore size distribution and pore characteristics of powders (solids) - Part 2: Measurement method for mesopores and macropores by gas adsorption." When the pore size is within this range, a geopolymer hardened body with excellent thermal insulation properties can be obtained.

[0036] (porosity) The porosity of the aerogel of this embodiment is preferably greater than 90%, 95% or more, 96% or more, etc. The upper limit is not particularly limited, and is preferably, for example, 99% or less, 98% or less, 97% or less, etc. By setting the porosity of the aerogel within the above range, a geopolymer hardened body with excellent thermal insulation properties can be obtained.

[0037] (density) The density of the aerogel of this embodiment is 50 kg / m 3 More than 60kg / m 3 More than 70kg / m 3 More than 80kg / m 3 More than 90kg / m 3 More than 100kg / m 3 More than 110kg / m 3 More than 275 kg / m 3 Below 250kg / m 3 Below 240kg / m 3 Below 230kg / m 3 Below 220kg / m 3 Below 210kg / m 3 Below 200kg / m 3 The following are preferred:

[0038] The density is measured in accordance with JIS K7222:2005 "Foamed plastics and rubber - Determination of apparent density".

[0039] (bulk density) The bulk density of the aerogel of this embodiment is 1 kg / m 3 More than 10kg / m 3 More than 20kg / m 3 More than 30kg / m 3 More than 40kg / m 3 More than 50kg / m 3 More than 60kg / m 3 More than 175 kg / m 3 Below 150kg / m 3 Below 140kg / m 3 Below 130kg / m 3 Below 120kg / m 3 Below 110kg / m 3Below 100kg / m 3 The following are preferred:

[0040] Bulk density can be measured by the tapping method (ISO 787-11). That is, the object is placed in a 250 mL measuring cylinder and the bulk density is calculated from the volume value after tapping 1250 times.

[0041] (BET specific surface area) The BET specific surface area of ​​the aerogel of this embodiment is 600 m 2 / g or more, 650m 2 / g or more, 700m 2 / g or more is preferable, and 800m 2 / g or less, 750m 2 / g or less, 700m 2 / g or less is preferable. By setting the BET specific surface area of ​​the aerogel within the above range, the viscosity of the composition for producing geopolymer becomes appropriate, making it easier to mix with other components. In addition, a hardened geopolymer with better thermal insulation properties can be obtained. The BET specific surface area can be measured as follows.

[0042] (Method for measuring BET specific surface area) The BET specific surface area is measured using a commercially available high-precision automatic gas adsorption apparatus (manufactured by Japan BEL Co., Ltd., trade name: BELSORP28), etc. In this case, nitrogen (N2) gas, which is an inert gas, is used as the adsorption gas.

[0043] Specifically, the amount of adsorption required to form a monolayer on the particle surface, Vm (cm 3 / g, and the BET specific surface area S (m 2 / g) can be calculated. S = 4.35 × Vm (m 2 / g)

[0044] 1-2-3.Content The content of the aerogel in this embodiment is preferably more than 0 mass%, 3 mass% or more, 5 mass% or more, 7 mass% or more, etc., relative to the total mass of the geopolymer production composition, and is preferably 30 mass% or less, 20 mass% or less, 15 mass% or less, etc., relative to the total mass of the geopolymer production composition. By setting the content of the aerogel within the above range, the thermal insulation properties of the geopolymer hardened body can be further improved.

[0045] 1-3. Acidic activators The acidic activator of this embodiment acts as a crosslinking agent when curing the geopolymer production composition. The acidic activator of this embodiment is not particularly limited, and known activators can be used. Examples include phosphoric acid-based activators, nitric acid-based activators, and sulfuric acid-based activators. Among these acidic activators, phosphoric acid-based activators are preferred in this embodiment. When a phosphoric acid-based activator is used as the acidic activator in this embodiment, the geopolymer skeleton of the hardened geopolymer described below will contain a phosphoric acid-derived structure. Below, we will explain the use of a phosphoric acid-based activator as an example of an acidic activator.

[0046] Even when an acidic activator other than a phosphoric acid activator is used as the acidic activator, the content (amount added) and concentration can be adjusted appropriately so that crosslinking by the activator proceeds sufficiently, referring to the case where a phosphoric acid activator is used as described below. For example, the content of the acidic activator relative to the total mass of the geopolymer production composition is preferably 1% by mass or more, 5% by mass or more, 8% by mass or more, and preferably 60% by mass or less, 55% by mass or less, 50% by mass or less, etc.

[0047] The phosphoric acid-based activator used as the acidic activator in this embodiment is not particularly limited. Examples of the phosphoric acid-based activator include a mixture such as an aqueous solution containing phosphoric acid (H3PO4), a solution containing phosphate ions (PO4 3- ) (phosphates). Phosphates react with water to form phosphate ions (PO4 3-), etc. Examples include ammonium dihydrogen phosphate (NH4H2PO4), sodium dihydrogen phosphate (NaH2PO4), potassium dihydrogen phosphate (KH2PO4), ammonium hydrogen phosphate ((NH4)2HPO4), sodium hydrogen phosphate (Na2HPO4), etc.

[0048] A suitable example of a phosphoric acid-based activator is a high-concentration aqueous phosphoric acid solution. The phosphoric acid concentration of the high-concentration aqueous phosphoric acid solution is preferably 45% by mass or more, 50% by mass or more, or 55% by mass or more, and is preferably 95% by mass or less, 90% by mass or less, or 85% by mass or less. By using a high-concentration aqueous phosphoric acid solution with the above phosphoric acid concentration, crosslinking and kneading can be carried out efficiently.

[0049] When preparing a geopolymer manufacturing composition, the ratio of the amount of high-concentration phosphoric acid aqueous solution added to the total mass of the geopolymer manufacturing composition is preferably 1% by mass or more, 5% by mass or more, 8% by mass or more, etc., and is preferably 60% by mass or less, 55% by mass or less, 50% by mass or less, etc.

[0050] The phosphoric acid concentration relative to the total mass of the composition for producing a geopolymer is, for example, preferably 0.4 to 57.0 mass%, more preferably 0.8 to 38.2 mass%, and even more preferably 0.8 to 13.6 mass%.

[0051] As long as the phosphoric acid concentration relative to the total mass of the geopolymer production composition is within the above-mentioned range, a high-concentration aqueous phosphoric acid solution or a phosphate salt may be used as the phosphoric acid activator. Furthermore, the order of mixing the components when preparing the geopolymer production composition is not particularly limited.

[0052] Specifically, when a high-concentration aqueous phosphoric acid solution is used as the phosphoric acid activator, the composition for producing geopolymers may be prepared by adding a mixture of water described below to the solid component while stirring the mixture. Also, when a phosphate salt is used as the acid activator, the composition for producing geopolymers may be prepared by adding water described below to a mixture of the phosphate salt and the solid component.

[0053] 1-4.Water The water in this embodiment may be deionized water, distilled water, or water containing up to 0.1% by mass of impurities, such as ordinary tap water.

[0054] The water content is not particularly limited as long as the phosphoric acid concentration relative to the total mass of the geopolymer production composition is within the above-mentioned range, and is preferably in the range of 5 to 50 mass% relative to the total mass of the geopolymer production composition.

[0055] 1-5. Filler 1-5-1. Ingredients The filler of this embodiment is a component other than the above-mentioned aluminosilicate and aerogel, and preferably includes inorganic particles (inorganic filler), etc. By using inorganic particles as the filler, the hardened geopolymer described below can be made less flammable even in high-temperature environments.

[0056] Examples of inorganic particles include oxides such as aluminum oxide, silicon dioxide (silica), spinel, zirconium oxide, magnesium oxide, titanium oxide, and cerium oxide; hydroxides such as aluminum hydroxide, calcium hydroxide, magnesium hydroxide, and aluminum hydroxide; carbides such as silicon carbide and boron carbide; nitrides such as silicon nitride and boron nitride; carbonates such as nickel carbonate, calcium carbonate, and magnesium carbonate; sulfates such as calcium sulfate; etc. One type selected from the above-mentioned inorganic particles may be used, or two or more types may be mixed and used.

[0057] The filler of this embodiment preferably contains silicon dioxide (silica) among the inorganic particles described above, and the content of silicon dioxide (silica) is preferably 90 mass% or more relative to the total mass of the filler. Silica is broadly divided into wet silica, which is synthesized in a liquid, and dry silica, which is synthesized by hydrolysis at high temperatures. In this embodiment, either wet silica or dry silica may be used as the filler. By including silica as a filler, the strength of the hardened geopolymer can be further improved.

[0058] 1-5-2.Shape / Structure The shape of the filler (inorganic particles) of this embodiment is not particularly limited and may be spherical, amorphous, or scaly, with spherical being preferred. Making the inorganic particles spherical can increase the fluidity of the geopolymer production composition after blending. The structure of the inorganic particles is not particularly limited and may be solid or hollow. Hollow refers to a structure having an internal cavity surrounded by an outer shell. The internal cavity may be sealed, or a portion of it may be connected to the outside.

[0059] 1-5-3.Physical properties / properties (Average particle size) The average particle size of the filler (inorganic particles) of this embodiment is preferably in the range of 0.1 to 100 μm, more preferably in the range of 1 to 50 μm, and even more preferably in the range of 5 to 15 μm.

[0060] (bulk density) The bulk density of the filler (inorganic particles) of this embodiment is 0.001 to 1.000 g / cm 3 The range of 0.010 to 0.500 g / cm is preferable. 3 The range of 0.050 to 0.200 g / cm is more preferable. 3 The bulk density is more preferably measured in the same manner as described above.

[0061] (BET specific surface area) The BET specific surface area of ​​the filler (inorganic particles) of this embodiment is 20 m 2 / g or more, 30m 2 / g or more, 50m 2 / g or more is preferable, and 600m 2 / g or less, 500m 2 / g or less, 450m 2 / g or less, 400m 2 / g or less is preferable. By setting the BET specific surface area of ​​the inorganic particles within the above range, the inorganic particle surface becomes moderately uneven, making it easier for the geopolymer hardened body to take in air and further improving its thermal insulation. The BET specific surface area can be measured using the same method as described above.

[0062] 1-5-4.Content The content of the filler (inorganic particles) in this embodiment is not particularly limited, and is preferably 5% by mass or more, 10% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, etc., based on the total mass of the geopolymer production composition, and is preferably 60% by mass or less, 55% by mass or less, 50% by mass or less, etc. By setting the content of the inorganic particles within the above range, the thermal insulation properties of the geopolymer hardened body can be further improved.

[0063] 1-6.Other ingredients The geopolymer production composition may contain other components as long as they do not impair the effects of the present invention. Examples of other components include pH adjusters, fluidizers, shrinkage reducers, rust inhibitors, waterproofing agents, setting retarders, antifoaming agents, dust reducers, pigments, etc. It may also contain glass fibers as reinforcing materials.

[0064] The content of the other components is not particularly limited, and is preferably in the range of 1 to 10% by mass relative to the total mass of the composition for producing a geopolymer.

[0065] 2. Hardened geopolymer The hardened geopolymer of this embodiment includes a geopolymer and an aerogel. The geopolymer is preferably obtained using an acidic activator, and among acidic activators, a phosphoric acid-based activator is more preferred. That is, the geopolymer is preferably obtained using a phosphoric acid-based activator, and the geopolymer skeleton preferably contains a phosphoric acid-derived structure. The aerogel is preferably silica aerogel.

[0066] 2-1. Manufacturing method The hardened geopolymer of this embodiment can be produced by mixing (kneading) the components of the composition for producing a geopolymer described above, followed by drying and hardening.

[0067] There are no particular limitations on the conditions for mixing the components of the geopolymer production composition, as long as a hardened geopolymer is obtained. The mixing method may involve kneading using a mortar mixer or concrete mixer. After kneading, the mixture is preferably cured at room temperature or with heating. The curing time varies depending on the temperature, with lower temperatures requiring longer curing times. For example, the curing time is generally 7 days or more at room temperature and 3 to 4 days at 60°C.

[0068] 2-2.Shape The hardened geopolymer of this embodiment is preferably in a sheet form, and can be formed into a sheet form by, for example, heat and pressure molding. Therefore, when the hardened geopolymer of this embodiment is formed into a sheet form by heat and pressure molding, it can be formed in a shorter curing time than the general curing time described above. Furthermore, a thermal insulation material including a sheet-shaped hardened geopolymer can be used for various applications (electronic components, mobile objects, etc.) described below.

[0069] 2-3.Physical properties (thermal conductivity) The thermal conductivity of the hardened geopolymer of this embodiment preferably has an upper limit of 100 mW / m·K or less, 90 mW / m·K or less, 80 mW / m·K or less, 70 mW / m·K or less, or 50 mW / m·K or less. The lower limit is not particularly limited and may be, for example, 5 mW / m·K or more. The thermal conductivity was measured using a thermal conductivity measuring device (HC-72 manufactured by Eiko Seiki Co., Ltd.) in accordance with JIS A1412-2:1999, "Method for measuring thermal resistance and thermal conductivity of thermal insulating materials - Part 2: Heat flow meter method (HFM method)." A thermal conductivity within the above range ensures sufficient thermal insulation even when formed into a sheet.

[0070] (Apparent density) The apparent density of the hardened geopolymer of this embodiment is 100 kg / m 3 More than 200kg / m 3 More than 300kg / m 3 It is preferable that the saturation is 1,060 kg / m or more. 3 Below 800kg / m 3 Below 600kg / m 3 Below 500kg / m 3 It is preferable that the apparent density is within the above range. If the apparent density is within the above range, the weight of the geopolymer hardened body can be reduced. In addition, since it becomes easier to trap air inside the geopolymer hardened body, the thermal insulation properties can be further improved. Here, the apparent density is measured using a method in accordance with JIS K7222:2005 "Foam plastics and rubber - Determination of apparent density."

[0071] (Compressive strength) The hardened geopolymer of this embodiment preferably has a compressive strength measured in a compression test (see the Examples below for details) of more than 0.3 MPa, 1 MPa or more, 5 MPa or more, 10 MPa or more, etc. If the compressive strength is within the above range, sufficient strength can be obtained even when the hardened geopolymer is formed into a sheet.

[0072] (Thermal insulation) The hardened geopolymer of this embodiment preferably has a surface temperature measured in an insulation test (see the Examples below for details) of 310°C or less, 300°C or less, 290°C or less, 280°C or less, 270°C or less, 260°C or less, 250°C or less, etc. The insulation properties of the hardened geopolymer of this embodiment can be evaluated by the insulation test.

[0073] In this embodiment, the hardened geopolymer body is produced using the composition for producing a geopolymer of the above-described aspect, but is not limited thereto. That is, the hardened geopolymer body of this embodiment may contain a geopolymer and an aerogel, and may have a thermal conductivity within the above range.

[0074] 3. Uses of insulation materials The heat insulating material of this embodiment preferably comprises the above-mentioned hardened geopolymer. Since the heat insulating material of this embodiment has excellent heat insulating properties even in sheet form, it can be suitably used as a heat insulating material for electronic components, a heat storage device used for various purposes including housing, vehicles, and industrial use, a heat insulating material used in the engine compartment of an automobile, a heat insulating material used to keep the passenger compartment of an automobile warm, a heat insulating material for covering an automobile fuel cell, and the like. [Example]

[0075] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the embodiments of the following examples.

[0076] Examples and Comparative Examples <Preparation of composition for geopolymer production> Each component of the geopolymer manufacturing composition was prepared as follows: Aluminosilicate metakaolin {Metakaolin: manufactured by Takehara Chemical Industry Co., Ltd., obtained by heating NN kaolin clay at 800°C for 10 hours to make it amorphous} Aerogel (physical properties are shown in Table 1 below) {Silica aerogel: P200, manufactured by Cabot Corporation} Acidic activator {Concentrated phosphoric acid aqueous solution (85%), manufactured by Kanto Chemical Co., Ltd.} Distilled water Filler {Wet silica: ULTRSIL VN3, manufactured by Evonik Japan Co., Ltd.} {Borosilicate glass: Tomoe Engineering Co., Ltd., Glass Balloon HL38} ·Reinforcement material {Glass fiber: CS6J-888, Nitto Boseki Co., Ltd., chopped strand}

[0077] [Table 1]

[0078] The above-mentioned solid components were mixed in the amounts shown in Table 2 below. The resulting mixture was added to a concentrated phosphoric acid aqueous solution while stirring under the stirring conditions below to prepare geopolymer production compositions for each example and comparative example. (stirring conditions) Mixer: Three-One Motor BL600 manufactured by Shinto Scientific Co., Ltd. Rotation speed: 790 rpm Mixing time: 20 minutes

[0079] The viscosity of the obtained geopolymer manufacturing composition was measured by the method shown below. The viscosity measurement results are shown in Table 2 below.

[0080] (viscosity) The viscosity is a B-type viscosity measured in accordance with JIS Z8803:2011 "Method for measuring viscosity of liquids." The viscosity was measured using a single cylindrical rotational viscometer (low viscosity spindle LV-4, rotation speed: 12 rpm).

[0081] <Manufacturing of hardened geopolymer> The resulting geopolymer manufacturing composition was cured under the following conditions. Specifically, the geopolymer manufacturing composition was poured into a silicone mold, heated, and molded while pressing with a 3 mm spacer. After demolding, the composition was cured in a constant temperature and humidity chamber to produce the hardened geopolymers of each example and comparative example. (Heating conditions) Temperature: 115℃ Time: 20 minutes (Curing conditions) Temperature: 23℃ Relative humidity: 55% Hours: 24 hours

[0082] The hardened geopolymers of each example and comparative example were subjected to thermal conductivity, apparent density measurements, insulation tests, and compression tests using the methods described below. The evaluation results are shown in Table 2 below.

[0083] (thermal conductivity) The thermal conductivity was measured using a thermal conductivity measuring device (HC-72 manufactured by Eiko Seiki Co., Ltd.) in accordance with JIS A1412-2:1999 "Methods for measuring thermal resistance and thermal conductivity of thermal insulating materials - Part 2: Heat flow meter method (HFM method)".

[0084] (Apparent density) The apparent density was measured according to JIS K7222:2005 "Foamed plastics and rubber - Determination of apparent density".

[0085] (Insulation test) Test samples (3 mm thick, 100 mm square) of the hardened geopolymer bodies of each example and comparative example were heated on a 500°C hot plate (C-MAG HP4, manufactured by IKA) for 5 minutes, and then the surface temperature of the center of each test sample was measured from a height of 200 mm using a thermal imaging radiation thermometer (FLIR TG167, manufactured by FLIR).

[0086] (Insulation evaluation criteria) A: Surface temperature is 300°C or less C: Surface temperature exceeds 300°C

[0087] (Compression test) Test samples (3 mm thick, 10 mm diameter) of the hardened geopolymer bodies of each example and comparative example were compressed across the entire surface at a compression rate of 1 mm / min using an autograph (AG-X 10 kN, manufactured by Shimadzu Corporation), and the compressive strength leading to material failure was measured.

[0088] (Compressive strength evaluation criteria) A: Compressive strength over 0.3 MPa C: Compressive strength is 0.3 MPa or less

[0089] [Table 2] *The blending amounts in Table 2 are shown in mass %. [Industrial Applicability]

[0090] The geopolymer hardened body and insulating material of the present invention have superior insulating properties and can therefore be used as insulating materials for electronic components, insulating materials used in automobile engine compartments, insulating materials used to keep automobile passenger compartments warm, automobile fuel cells, or insulating materials covering automobile power storage devices.

Claims

1. A geopolymer hardened body comprising a geopolymer and an aerogel and having a thermal conductivity of 100 mW / m·K or less.

2. A thermal insulation material comprising the hardened geopolymer of claim 1.

3. A composition for producing a geopolymer, comprising an aluminosilicate, an aerogel, an acidic activator, and water.

4. The geopolymer manufacturing composition of claim 3, wherein the aerogel is a silica aerogel.

5. The composition for producing geopolymers according to claim 3, wherein the content of the aerogel is greater than 0% by mass.

6. The geopolymer manufacturing composition of claim 3, further comprising a filler other than the aerogel.

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