Composite panel

Abstract

To provide a composite panel which is excellent in fire resistance and heat insulation, and hardly causes dew condensation.SOLUTION: And a geopolymer layer, wherein the geopolymer layer comprises a plurality of bubbles formed by foaming, an equilibrated volumetric water content of the geopolymer layer at a relative humidity of 55% measured according to JISA1475 2019 is greater than or equal to 5 * 10-humidity / 3m3, and a m3 storage amount of the geopolymer layer in a medium-humidity area measured according to JISA1470 1:2014 is less than or equal to 25g / m2 (including 0).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to composite panels. [Background technology]

[0002] Conventionally, composite panels comprising a layer made of a resin foam board and a layer made of an inorganic material have been known. Such composite panels are used for various purposes, such as wall materials, roofing materials, and flooring materials for buildings. Furthermore, the composite panels are required to have sufficient fire resistance, heat insulation, and the like, depending on the various applications.

[0003] For example, Patent Document 1 describes a fire-resistant composite structure (composite panel) comprising a foam material (a layer made of a resin foam board), a geopolymer thermal protection layer adhered to the foam material, and a surface material adhered to the geopolymer layer. Note that geopolymers are known as inorganic polymers that are reaction products of silicates of divalent or higher metals and alkali metal silicates. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication 2015-518435 Summary of the Invention [Problem to be solved by the invention]

[0005] However, a composite panel having a layer made of a foam material and a geopolymer layer as disclosed in Patent Document 1 has a problem in that condensation is likely to occur when used for construction purposes such as wall materials, roof materials, and floor materials in buildings. Also, such composite panels have a problem in that once they absorb moisture, their insulating properties tend to remain reduced for a long time.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a composite panel that is excellent in fire resistance and heat insulation, and is less susceptible to condensation. [Means for solving the problem]

[0007] In order to solve the above problems, the following composite panel is provided.

[0008] [1] A composite panel comprising a synthetic resin foam board layer and a geopolymer layer, The geopolymer layer contains a large number of bubbles formed by foaming, The equilibrium volumetric moisture content of the geopolymer layer at 55% humidity, measured according to JIS A 1475:2019, is 5 x 10 -3 m 3 / m 3 That's all, The moisture storage capacity of the geopolymer layer in a medium humidity area is 25 g / m, as measured based on JIS A 1470-1:2014. 2 A composite panel that is less than or equal to (including 0).

[0009] [2] The product of the thickness of the geopolymer layer and the density of the geopolymer layer is 2 to 10 kg / m 2 The composite panel of [1] above.

[0010] [3] The density of the geopolymer layer is 150 to 700 kg / m 3 The composite panel according to [1] or [2] above.

[0011] [4] The composite panel according to any one of [1] to [3], wherein the average bubble diameter of the geopolymer layer is 0.1 to 5 mm.

[0012] [5] The area of ​​the composite panel in top view is 500 cm 2 The composite panels of [1] to [4] above.

[0013] [6] The adhesive strength between the geopolymer layer and the synthetic resin foam board layer is 5N / cm 2The composite panel of any one of [1] to [5] above. [Effects of the Invention]

[0014] The composite panel of the present invention is excellent in fire resistance and heat insulation, and is also resistant to condensation. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view illustrating one embodiment of a composite panel of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment of the composite panel of the present invention will be described below: Fig. 1 is a cross-sectional view illustrating an embodiment of the composite panel of the present invention.

[0017] The composite panel P of the present invention comprises a synthetic resin foam board layer 1 and a geopolymer layer 2. In the embodiment illustrated in Fig. 1, the composite panel P is formed by laminating the synthetic resin foam board layer 1 and the geopolymer layer 2 together by bonding them together.

[0018] The synthetic resin foam board layer 1 and the geopolymer layer 2 of the composite panel P of the present invention will be described in detail below.

[0019] [Geopolymer layer] Geopolymers are the reaction products of silicates of divalent or higher metals and alkali metal silicates.

[0020] Examples of divalent or higher metals include aluminum, calcium, magnesium, titanium, and iron. The silicate of a divalent or higher metal is preferably an aluminosilicate, and the geopolymer is preferably a reaction product of an aluminosilicate and an alkali metal silicate. A geopolymer, which is a reaction product of an aluminosilicate and an alkali metal silicate, has a tetrahedral structure formed from SiO4 and AlO4, and is an inorganic polymer having a structure in which cations that compensate for the negative charge of AlO4 are contained in the network of the tetrahedral structure.

[0021] The geopolymer layer of the present invention is a layer containing numerous bubbles formed by foaming. In other words, the geopolymer layer of the present invention can also be said to be a foamed layer (geopolymer foamed layer). Geopolymers usually have mesopores (pores of 2 to 50 μm) derived from the geopolymer structure, but these mesopores are distinguished from the numerous bubbles in the geopolymer layer formed by the foaming agent. Note that the geopolymer layer in the composite structure (composite panel) of the above-mentioned Patent Document 1 does not contain numerous bubbles formed by foaming.

[0022] Geopolymers are environmentally friendly materials with relatively low carbon dioxide emissions during the manufacturing process, and are also expected to be used as materials for constructing architectural composite panels because they have properties such as moisture absorption, fire resistance, and odor absorption. However, composite panels with non-foamed geopolymer layers, such as those disclosed in Patent Document 1, have the problem of being prone to condensation.

[0023] In the present invention, by forming a composite panel having a geopolymer layer with a large number of bubbles and the properties described below, it is possible to obtain a composite panel that is fire-resistant and resistant to condensation.

[0024] The geopolymer layer has an equilibrium volumetric moisture content of 5×10 at 55% humidity, measured according to JIS A 1475:2019. -3 m 3 / m 3That's all. The equilibrium volumetric moisture content is an index that indicates how much moisture the geopolymer layer can absorb under a certain humidity. When the equilibrium volumetric moisture content of the geopolymer layer is in this range and the moisture storage capacity of the geopolymer layer, which will be described later, is in a specific range, the composite panel has excellent fire resistance and heat insulation properties and is less likely to cause condensation.

[0025] From the viewpoint of increasing the moisture absorption amount of the geopolymer layer, the equilibrium volumetric moisture content of the geopolymer layer is 6 × 10 -3 m 3 / m 3 It is preferable that the value is 7×10 or more. -3 m 3 / m 3 The upper limit of the equilibrium volumetric water content of the geopolymer layer is not particularly limited, but from the viewpoint of facilitating early release of water in the geopolymer layer, it is preferably about 30 × 10 -3 m 3 / m 3 and 20×10 -3 m 3 / m 3 It is more preferable that -3 m 3 / m 3 It is more preferable that:

[0026] The equilibrium volumetric water content of a geopolymer layer can be increased by increasing the amount of aluminum element contained in the geopolymer structure and increasing the number of mesopores in the geopolymer structure. Also, increasing the density of the geopolymer layer can increase the equilibrium volumetric water content of the geopolymer layer.

[0027] The geopolymer layer has a moisture storage capacity of 25g / m in a medium humidity range, measured according to JIS A 1470-1:2014. 2The moisture storage capacity is equal to or less than 0 (including 0). The moisture storage capacity corresponds to the amount of moisture contained in the geopolymer layer after the geopolymer layer has been allowed to absorb moisture for a predetermined time under a predetermined humidity and then released for a predetermined time under the same humidity, and is therefore an indicator of the ease of moisture release in the geopolymer layer. When the equilibrium volumetric water content of the geopolymer layer is within the above range and the moisture storage capacity of the geopolymer layer is within this range, the composite panel has excellent fire resistance and heat insulation properties and is less susceptible to condensation.

[0028] The geopolymer layer will be more moisture-releasing, and from the viewpoint of creating a composite panel with superior humidity control performance, the moisture storage capacity of the geopolymer layer is set at 20 g / m 2 It is preferable that the density is 16 g / m or less (including 0). 2 It is more preferable that the density of the geopolymer layer is less than or equal to 0 (including 0). In a geopolymer layer containing a large number of bubbles formed by foaming, the moisture storage capacity of the geopolymer layer can be reduced by lowering the density of the geopolymer layer while exposing the bubbles to the surface. In addition, the moisture storage capacity of the geopolymer layer can be reduced by increasing the average bubble diameter of the geopolymer layer. In this way, the geopolymer layer containing a large number of bubbles increases the contact surface between the geopolymer and air within the geopolymer layer, which is thought to result in a geopolymer layer that is easy to absorb and release moisture at a moderate rate.

[0029] The density of the geopolymer layer is 150-700 kg / m 3 When the density of the geopolymer layer is in this range, the above equilibrium volumetric water content is preferably 5×10 -3 m 3 / m 3 The moisture content is likely to exceed 25g / m 2 The density of the geopolymer layer is preferably 200 kg / m or less (including 0), so that the composite panel has excellent fire resistance and heat insulation properties and is less susceptible to condensation. From the viewpoint of increasing the moisture absorption amount of the geopolymer layer and making it easier to increase the equilibrium volumetric water content and to improve the fire resistance of the composite panel, the density of the geopolymer layer should be 200 kg / m or less. 3 It is preferable that the saturation is 250 kg / m or more. 3More preferably, it is 300 kg / m or more. 3 From the viewpoint of increasing the moisture release property of the geopolymer layer and easily reducing the moisture storage amount, the density of the geopolymer layer is preferably 600 kg / m or more. 3 Preferably, it is 550 kg / m or less. 3 More preferably, it is 500 kg / m or less. 3 It is even more preferable that:

[0030] The thickness of the geopolymer layer is preferably 3 mm or more, more preferably 5 mm or more, from the viewpoint of forming a composite panel that can stably exhibit the effects of the present invention. Furthermore, although the thickness of the geopolymer layer depends on the application, from the viewpoint of improving lightness and ease of handling, it is preferably 500 mm or less, more preferably 300 mm or less, even more preferably 100 mm or less, even more preferably 50 mm or less, and particularly preferably 30 mm or less.

[0031] The geopolymer layer is preferably in the form of a plate.

[0032] The geopolymer layer should be such that the product of the thickness and density of the geopolymer layer is 2 to 10 kg / m 2 When the product of the thickness and density of the geopolymer layer is within this range, it is easy to stably form a lightweight geopolymer layer with a high equilibrium volumetric water content. This makes it possible to stably obtain a lightweight composite panel that is excellent in fire resistance and is less susceptible to condensation.

[0033] The geopolymer layer preferably has an average bubble diameter (average bubble diameter) of 0.1 to 5 mm. This range of average bubble diameters facilitates the formation of a geopolymer layer with an equilibrium volumetric moisture content above a specific value and a moisture storage capacity below a specific value. Therefore, the composite panel exhibits excellent fire resistance and thermal insulation properties, as well as a stable condensation resistance. From the perspective of reducing the moisture storage capacity of the geopolymer layer, the average bubble diameter of the geopolymer layer is preferably 0.3 mm or more, more preferably 0.5 mm or more. Furthermore, from the perspective of achieving a relatively uniform bubble structure in the geopolymer layer and stably achieving the effects of the geopolymer layer, the average bubble diameter of the geopolymer layer is preferably 4 mm or less, more preferably 3 mm or less. The average bubble diameter (average bubble diameter) can be calculated by taking an image of a cross section of the geopolymer layer along its thickness direction, measuring the circular equivalent bubble diameter of each bubble in the image, and then arithmetically averaging these values. Specifically, it can be measured by the method described in the Examples below.

[0034] Furthermore, it is preferable that the geopolymer layer has a large number of bubbles exposed on the surface when viewed from the top of the composite panel. If a skin layer (a solid layer made of geopolymer that substantially does not contain bubbles) is formed on the surface of the geopolymer layer, the bubbles can be exposed by removing the skin layer by cutting or the like and forming a cross section of the geopolymer layer. This makes it easier to form a geopolymer layer with the moisture storage capacity below the specified value, and the composite panel has excellent fire resistance and insulation properties and is less susceptible to condensation.

[0035] The molar ratio of aluminum element content to silicon element content (Al / Si) in the geopolymer structure is preferably 0.2 to 2, more preferably 0.3 to 1. When the molar ratio in the geopolymer structure is within this range, the equilibrium volumetric water content of the geopolymer layer can be increased while maintaining the strength of the geopolymer layer. Note that the above molar ratio is the composition ratio in the geopolymer structure, which is an inorganic polymer, and is the molar ratio obtained without including silicon element and aluminum element derived from aggregates, etc.

[0036] Aluminosilicates (xM2O·yAl2O3·zSiO2·nH2O, where M is an alkali metal), which are preferably used to form geopolymer layers, are compounds whose structure involves replacing some of the silicon atoms in silicates with aluminum atoms.

[0037] The SiO2 (silicon dioxide) content in the aluminosilicate is preferably 20% by mass to 80% by mass, more preferably 30% by mass to 70% by mass, based on the total mass of the aluminosilicate (100% by mass). When the SiO2 content in the aluminosilicate is within this range, the resulting geopolymer layer is likely to form a good cellular structure with many bubbles.

[0038] The Al2O3 content in the aluminosilicate is preferably 20% by mass to 70% by mass, more preferably 30% by mass to 50% by mass, based on the total mass of the aluminosilicate (100% by mass). When the Al2O3 content is in this range, it is easy to improve the compressive strength of the geopolymer layer.

[0039] The SiO2 content and Al2O3 content in the aluminosilicate can be determined by quantifying each element using an X-ray fluorescence analyzer (for example, EA6000V manufactured by Hitachi High-Tech Science) or the like.

[0040] Examples of aluminosilicates include clay minerals such as beidellite, bentonite, metakaolin, kaolinite, halloysite, montmorillonite, pyrophyllite, vermiculite, mica, chlorite, saponite, sepiolite, and acid clay; industrial wastes such as fly ash, red mud, silica fume, blast furnace slag, rice husks, and sewage sludge incineration ash; natural aluminosilicate minerals and their calcined products (e.g., metakaolin: Al2O3·2SiO2); volcanic ash; and other aluminum-containing silicate minerals. These may be used alone or in combination. When using a combination of two or more aluminosilicates, it is preferable to blend them so that the SiO2 and Al2O3 contents fall within the above-mentioned ranges. Among these, aluminosilicates primarily composed of metakaolin are preferred. Aluminosilicates of the desired composition can be prepared by appropriately grinding and classifying these materials and using specific fractions.

[0041] When metakaolin is used as the aluminosilicate, the proportion of metakaolin in the aluminosilicate is preferably 50% by mass or more. When the proportion of metakaolin in the aluminosilicate is within the above range, a good cell structure with a large number of bubbles is easily formed. From the above viewpoints, the proportion of metakaolin in the aluminosilicate is more preferably 60% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0042] The average particle size of the aluminosilicate is preferably 0.1 μm to 50 μm, more preferably 0.3 μm to 30 μm, and even more preferably 0.5 μm to 10 μm. When the average particle size of the aluminosilicate is within this range, the produced geopolymer layer forms a good cellular structure. The average particle size refers to the diameter of a hypothetical sphere having the same volume as the particle.

[0043] The crystallinity of the aluminosilicate is preferably 20% or less, more preferably 10% or less. When the crystallinity of the aluminosilicate is within this range, when the aluminosilicate is reacted with an alkali metal silicate (described later) in an aqueous solution, the alkali component derived from the alkali metal silicate facilitates elution of aluminum ions from the aluminosilicate source, and silicate monomers are readily produced, stably carrying out polycondensation, and thus a favorable cell structure is readily formed.

[0044] The crystallinity can be determined based on the method (absolute method) described in JIS K0131-1996. For example, the crystallinity can be measured by performing X-ray diffraction measurement on an aluminosilicate powder using an X-ray analyzer equipped with a two-dimensional detector (e.g., SmartLab manufactured by Rigaku Corporation) at room temperature with the 2θ range set to 10 to 40°. The crystallinity can be determined by performing profile fitting on the diffraction pattern measured by X-ray diffraction measurement and calculating the ratio of the peak area of ​​the crystalline component to the total peak area ([peak area of ​​the crystalline component] + [halo pattern area of ​​the amorphous component]) from the obtained X-ray diffraction.

[0045] Examples of alkali metal silicates include potassium silicate, sodium silicate (water glass), and lithium silicate, and one or more of these can be used. Among these, potassium silicate is preferred as the alkali metal silicate. The molar ratio of SiO2 to K2O (SiO2 / K2O ratio) in potassium silicate is preferably 1 or more and 5 or less, more preferably 1.5 or more and 4.5 or less, and even more preferably 3 or more and 4 or less. By setting the molar ratio (SiO2 / K2O ratio) within the above range, the strength of the geopolymer layer can be further improved.

[0046] The geopolymer layer is based on the reaction product (i.e., geopolymer) of the above-mentioned aluminosilicate and alkali metal silicate. Specifically, the content of the geopolymer in the geopolymer layer is preferably 40% by mass or more, more preferably 50% or more, and even more preferably 60% or more.

[0047] The geopolymer layer also preferably contains aggregate.

[0048] Examples of aggregates include one or more of mica, wollastonite, chalk, talc, molokite, cordierite, basalt, feldspar, zircon, graphite, and borax. Of these, mica is preferred as the aggregate. Mica is a silicate mineral generally called muscovite, and is KAl2(AlSiO 10 )(F,OH)2. In the present invention, the term "mica" encompasses sheet silicate (phyllosilicate) minerals that are physically and chemically similar. When mica is included in the aggregate, it is preferable that the average particle size of the mica be 50 μm or more and 200 μm or less, from the viewpoint of forming a good cell structure.

[0049] The aggregate content in the geopolymer layer is preferably 5% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less.

[0050] Furthermore, to stably produce a geopolymer layer having the aforementioned properties, the geopolymer layer preferably contains a foam nucleating agent. Examples of foam nucleating agents include inorganic powders such as talc and calcium carbonate, with talc being preferred. From this perspective, the content of the foam nucleating agent in the geopolymer layer is 1% by mass or more and 20% by mass or less, more preferably 2% by mass or more and 15% by mass or less, and even more preferably 3% by mass or more and 10% by mass or less. The geopolymer layer may further contain, for example, a cell-opening agent, reinforcing fibers, etc., as long as the intended object of the present invention can be achieved.

[0051] The reinforcing fibers are contained in the geopolymer layer to improve its strength and prevent cracking. Examples of reinforcing fibers include vinylon fiber, polypropylene fiber, aramid fiber, acrylic fiber, rayon fiber, carbon fiber, glass fiber, potassium titanate whisker, alumina fiber, steel wool, and slag wool. The reinforcing fibers contained in the geopolymer layer can increase the strength of the geopolymer layer.

[0052] Examples of the cell-opening agent that can be used include microorganisms such as yeast and algae, proteins, and surfactants.

[0053] Furthermore, the ratio of the number of moles of Ca element to the total number of moles of Al element and Si element in the geopolymer layer (Ca / (Al+Si)) is preferably 0.4 or less (including 0), more preferably 0.2 or less (including 0), even more preferably 0.1 or less (including 0), particularly preferably 0.05 or less (including 0), and most preferably 0.01 or less (including 0). Having the molar ratio (Ca / (Al+Si)) in the above range improves fire resistance. Note that aluminosilicates and alkali metal silicates used to form the geopolymer layer may contain calcium element as an impurity or secondary component. However, from the viewpoint of stably increasing the fire resistance of the geopolymer layer, it is preferable to form the geopolymer layer so that such calcium element is substantially not contained.

[0054] [Synthetic resin foam board layer] As the synthetic resin foam board for forming the synthetic resin foam board layer in the composite panel, a known foam board used as a heat insulating material for buildings, etc. can be used. By including the synthetic resin foam board layer in the composite panel, the heat insulating properties of the composite panel can be improved.

[0055] Specifically, the synthetic resin foam board may be a foam board made of a thermoplastic resin such as polystyrene, polyethylene, polypropylene, polyurethane, or polyvinyl chloride as a base resin. Among these, polystyrene-based resin foam boards are preferred because of their excellent water resistance, high strength even at low density, and ease of improving the thermal insulation of composite panels. Furthermore, the synthetic resin foam board may be an extruded foam or an in-mold molded foam made of foamed beads. An extruded foam refers to a foam molded product obtained by adding a blowing agent to a resin heated and melted in an extruder to form a foamable resin melt, and then extruding the melt under a pressure lower than that within the extruder. An in-mold molded foam made of foamed beads refers to a foam molded product obtained by filling foamed beads into a mold and heating it with steam or the like to form it in-mold.

[0056] The synthetic resin foam board layer may be in the form of a laminate in which two or more layers of one or more types of synthetic resin foam boards are bonded together.

[0057] The density of synthetic resin foam board is 10 to 100 kg / m 3 is preferably 15 to 80 kg / m 3 More preferably, it is 20 to 50 kg / m 3 It is particularly preferable that the density of the synthetic resin foam board is in this range. When the density of the synthetic resin foam board is in this range, it is easy to obtain a composite panel that has a good balance of good heat insulation and strength. The density is calculated by multiplying the weight [kg] of the synthetic resin foam board by its volume [m 3 ] shall be obtained by dividing by

[0058] The thickness of the synthetic resin foam board layer depends on the application, but from the viewpoint of ensuring the thermal insulation properties of the composite panel while improving the workability of the composite panel, it is preferably 10 mm or more and 300 mm or less, more preferably 15 mm or more and 200 mm or less, and even more preferably 20 mm or more and 60 mm or less.

[0059] The compressive strength of the synthetic resin foam board in the thickness direction is 30 kN / m 2Preferably, it is 50 kN / m or more. 2 More preferably, it is 100 kN / m or more. 2 It is more preferable that the compressive strength in the thickness direction of the synthetic resin foam board is about 800 kN / m or more from the viewpoint of increasing the lightness of the composite panel. 2 In this specification, the compressive strength is the compressive stress at 10% deformation (10% deformation compressive stress) based on a compression test in accordance with JIS K 7220:2006.

[0060] Composite Panel The area of ​​the composite panel P in top view depends on the application, but from the viewpoint of improving the workability of the composite panel P, it is recommended to use a surface area of ​​500 cm 2 It is preferable that the temperature is 1000 cm or more. 2 More preferably, it is 2000 cm or more. 2 More preferably, it is 5000 cm or more. 2 On the other hand, from the viewpoint of improving the ease of handling of the composite panel P, the upper limit of the area of ​​the composite panel P in a top view is approximately 50,000 cm 2 and this is preferably 30,000 cm 2 is.

[0061] The thickness of the composite panel P is preferably 10 mm or more and 500 mm or less, more preferably 15 mm or more and 300 mm or less, and more preferably 20 mm or more and 200 mm or less, in order to achieve the effects of the composite panel P while improving the workability of the composite panel P.

[0062] In addition, 1m of composite panel P 2 The mass per unit area of ​​the composite panel P is preferably 1 kg or more and 20 kg or less, and more preferably 2 kg or more and 15 kg or less. 2 The mass per unit area is calculated by multiplying the thickness of the geopolymer layer by the density of the geopolymer layer (kg / m 2 ) and the product of the thickness of the synthetic resin foam board and the density of the synthetic resin foam board (kg / m 2 ) and can also be said to be a harmony.

[0063] The adhesive strength between the geopolymer layer 2 and the synthetic resin foam board layer 1 is 5N / cm 2 It is preferable that the resistance is 10N / cm or more. 2 It is more preferable that the adhesive strength is equal to or greater than this. When the composite panel P has the above adhesive strength, the geopolymer layer 2 and the synthetic resin foam board layer 1 are sufficiently bonded together, making them less likely to separate when the composite panel P is being constructed or used. From this perspective, it is preferable that the geopolymer layer 2 and the synthetic resin foam board layer 1 are laminated and bonded together via an adhesive. As the adhesive, for example, an ethylene-vinyl acetate copolymer emulsion adhesive or a modified silicone resin adhesive can be used. There is no particular upper limit set for the adhesive strength between the geopolymer layer 2 and the synthetic resin foam board layer 1, but it is generally preferable that the adhesive strength be 100 N / cm 2 and 50N / cm 2 The adhesive strength can be measured by the method described in the examples below.

[0064] The composite panel P of the present invention is suitable for use as an architectural composite panel, for example, for wall materials, roof materials, floor materials, etc. In addition, since the composite panel P of the present invention has the geopolymer layer 2 having the above-described properties, it has excellent fire resistance and can suppress the occurrence of condensation.

[0065] [Manufacturing method for composite panels] An embodiment of the method for producing a composite panel of the present invention will be described below. The production method of the present invention preferably includes the following first, second and third steps. First step: A step of obtaining a slurry containing a silicate of a divalent or higher metal, an alkali metal silicate, and water. Second step: A step of adding a foaming agent to the slurry to obtain a foamable slurry. Third step: A step of forming a geopolymer layer by foaming a reaction product of silicate of a divalent or higher metal and alkali metal silicate in a foamable slurry that is layered on a synthetic resin foam board layer with an adhesive.

[0066] The first to third steps will be described in detail below.

[0067] <1st process> In the first step, a mixture containing a silicate of a divalent or higher metal and, optionally, aggregates, etc., is mixed with an alkali metal silicate and, optionally, water for viscosity adjustment to obtain a slurry. In the slurry, the aluminosilicate reacts with the alkali metal silicate to form a geopolymer. The following describes the case where an aluminometal silicate is used as the silicate of a divalent or higher metal.

[0068] For the aluminosilicate and alkali metal silicate used to form the slurry, the above-mentioned descriptions of the various aluminosilicates and alkali metal silicates can be referred to as appropriate.

[0069] When aluminosilicate reacts with alkali metal silicate, it releases aluminum ions into the aqueous solution and produces silicate monomers (silicic acid, Si(OH)4) in the slurry. The resulting silicate monomers undergo polycondensation with the cations present in the reaction slurry, forming a geopolymer with a polymer network of SiO4·AlO4 tetrahedral structure.

[0070] Furthermore, dissolving alkali metal silicate in water to form an alkali metal silicate aqueous solution results in a highly alkaline solution, making the slurry highly alkaline. In the slurry, the alkali metal silicate in the alkali metal silicate aqueous solution reacts with the aluminosilicate, dissolving cations such as Al from the aluminosilicate into the slurry. In addition, silicate monomers are present in the slurry. Therefore, the alkali metal silicate serves as a source of silicate monomers that form geopolymers through polycondensation.

[0071] The alkali metal silicate is preferably added as an aqueous alkali metal silicate solution to form a slurry. For example, the concentration of the alkali metal silicate in the aqueous alkali metal silicate solution is preferably 20% by mass or more and 60% by mass or less, more preferably 22% by mass or more and 50% by mass or less, and even more preferably 25% by mass or more and 45% by mass or less. When the concentration of the alkali metal silicate is within the above range, the foam moldability of the slurry obtained by mixing the aluminosilicate and the aqueous alkali metal silicate solution can be improved. However, as long as the reaction between the alkali metal silicate and the aluminosilicate occurs, it is not essential to use the alkali metal silicate as the aqueous alkali metal silicate solution.

[0072] To adjust the pH of the slurry to a range of 13 to 14 and promote the reaction between the aluminosilicate and the alkali metal silicate, an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide can be added. Addition of potassium hydroxide to the slurry is particularly preferred. The amount of potassium hydroxide added is preferably 10 to 90 parts by mass, more preferably 50 to 80 parts by mass, per 100 parts by mass of the alkali metal silicate.

[0073] The amount of alkali metal silicate added is preferably 20 to 200 parts by mass, more preferably 40 to 100 parts by mass, based on 100 parts by mass of the SiO2 component in the aluminosilicate, from the viewpoint of forming a good cellular structure of the geopolymer layer and uniformly dispersing each component in the foamable slurry. It is preferable to add an aqueous solution of alkali metal silicate so that the amount of alkali metal silicate added falls within the above range.

[0074] The various aggregates described above are used as the aggregate contained in the slurry. From the viewpoint of suppressing cracking in the geopolymer layer while improving compressive strength, the content of aggregate in the expandable slurry described below is preferably 5% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less.

[0075] The aluminosilicate, alkali metal silicate, and aggregate may contain other components. In this case, the amounts of the aluminosilicate, alkali metal silicate, and aggregate added are calculated as the amount of active ingredient excluding the other components for each of the aluminosilicate, alkali metal silicate, and aggregate. The content of the SiO2 component in the aluminosilicate and the content of the SiO2 component in the alkali metal silicate can be determined by, for example, composition analysis using X-rays or the like to determine their abundance ratio.

[0076] The amount of water added to adjust the viscosity of the expandable slurry is not particularly limited as long as it is within a range that can achieve the intended object of the present invention, but for example, it is preferably 10% by mass or more and 50% by mass or less, and more preferably 20% by mass or more and 40% by mass or less, based on 100% by mass of the expandable slurry obtained in the second step described below. Water may be added independently, or may be added as a solvent when water glass is used as the alkali metal silicate.

[0077] The mixing method in the first step is not particularly limited, and for example, the materials can be mixed using a known mixer at room temperature (25° C.) Examples of the mixer include a mortar mixer, tilting mixer, truck mixer, twin-screw mixer, omni mixer, pan mixer, planetary mixer, and Eirich mixer.

[0078] <Second process> In the second step, as described above, a foaming agent or the like is added to the slurry obtained in the first step to obtain a foamable slurry. Examples of foaming agents include hydrogen peroxide, sodium peroxide, potassium peroxide, sodium perborate, and non-ferrous metal powder. Examples of non-ferrous metal powder include aluminum powder. Among these, it is preferable to use at least one of hydrogen peroxide and non-ferrous metal powder, and it is more preferable to use hydrogen peroxide.

[0079] When hydrogen peroxide is used as a foaming agent, it is preferably used as a hydrogen peroxide solution. In this case, the concentration of hydrogen peroxide in the hydrogen peroxide solution is preferably 10% by mass or more and 50% by mass or less. When the concentration of hydrogen peroxide in the hydrogen peroxide solution is within the above range, the geopolymer in the foamable slurry can be stably foamed, making it easier to obtain a geopolymer layer with a good bubble structure. From the above perspective, the concentration of hydrogen peroxide in the hydrogen peroxide solution is more preferably 20% by mass or more and 40% by mass or less.

[0080] The amount of foaming agent added can be appropriately set depending on the design of the geopolymer foam layer to be produced, but is preferably 0.5 parts by mass or more to 100 parts by mass or less, more preferably 1 part by mass or more to 50 parts by mass or less, and even more preferably 2 parts by mass or more to 20 parts by mass or less, relative to 100 parts by mass of the SiO2 component in the aluminosilicate. When hydrogen peroxide is used as a foaming agent, the amount of hydrogen peroxide added is preferably 0.5 parts by mass or more to 200 parts by mass or less, more preferably 1 part by mass or more to 150 parts by mass or less, and even more preferably 2 parts by mass or more to 100 parts by mass or less, relative to 100 parts by mass of the SiO2 component in the aluminosilicate. By adding the amount of foaming agent within the above range, the geopolymer in the foamable slurry is sufficiently foamed, making it easier to form a geopolymer layer having the above equilibrium volumetric water content and the above moisture storage amount.

[0081] <3rd process> In the third step, a formwork is prepared in which a layer of synthetic resin foam board and a layer of geopolymer can be laminated while forming a geopolymer layer. After placing the synthetic resin foam board in the formwork, an expandable slurry is introduced onto the synthetic resin foam board via an adhesive, and the reaction product (geopolymer) of the silicate of a divalent or higher metal (aluminosilicate) and the alkali metal silicate in the expandable slurry is expanded.

[0082] The shape of the mold used in the third step can be appropriately designed depending on the desired shape of the laminate. As the adhesive, for example, an ethylene-vinyl acetate copolymer emulsion adhesive or a modified silicone resin adhesive can be used.

[0083] By solidifying and expanding the geopolymer in the expandable slurry introduced into the formwork, numerous air bubbles are formed in the geopolymer layer, and a composite panel is obtained in which the formed geopolymer layer and the synthetic resin foam board layer are bonded together. If a skin layer is formed on the surface of the formed geopolymer layer after the third step, a step (fourth step) can be performed to expose the air bubbles on the surface of the geopolymer layer. In this step, for example, the skin layer formed on the geopolymer layer can be cut, thereby exposing the cross section of the geopolymer layer when viewed from above.

[0084] The conditions for foaming the geopolymer are set appropriately depending on the desired physical properties of the geopolymer layer. For example, when foaming the geopolymer by the casting method, the geopolymer can be solidified and foamed in a mold at a temperature of 20 to 100°C (preferably 50 to 80°C) for a holding time of 30 minutes to 24 hours to form a geopolymer layer.

[0085] When the casting method is used, the bubbles formed by the foaming of the geopolymer in the third step grow and become larger within 30 minutes to 1 hour after the foaming agent is added.

[0086] In the third step of this embodiment, an example is given of the formation of a geopolymer layer and the lamination and bonding of the geopolymer layer and the synthetic resin foam board layer in parallel, but it is also possible to obtain a composite panel, for example, by preparing a plate-shaped geopolymer foam formed from a foamable slurry in advance and laminating and bonding this geopolymer foam and a synthetic resin foam board using an adhesive.

[0087] From the viewpoint of being able to stably increase the adhesive strength between the geopolymer layer and the synthetic resin foam board layer, it is preferable to obtain a composite panel by foaming the geopolymer in the expandable slurry laminated on the synthetic resin foam board layer via an adhesive to form a geopolymer layer. [Example]

[0088] The composite panel of the present invention will be described below with reference to examples, but the composite panel of the present invention is not limited to the following examples.

[0089] The materials used for the geopolymer layers in the composite panels are as follows: Aluminosilicate: Metakaolin (Hyogo Clay Co., Ltd.: HC-K-1300W) Alkali metal silicate solution: A solution prepared by mixing potassium silicate (Nippon Chemical Industry Co., Ltd.: 2K potassium silicate), potassium hydroxide (Fujifilm Wako Pure Chemical Industries Co., Ltd.: special grade), and distilled water, with the molar ratio of Si / K adjusted to 0.625. Aggregate: Mica (Seishin Enterprise Co., Ltd.: C100M) Bubble nucleating agent: Talc (Matsumura Sangyo Co., Ltd.: Hi-filler 5000PJS) Foaming agent: Hydrogen peroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.: concentration 30% by mass)

[0090] Composite panels having a geopolymer layer and a synthetic resin foam board layer were manufactured by the following method (Examples 1 to 7 and Comparative Examples 1 to 5).

[0091] Example 1 A mixture of aluminosilicate (100 parts by mass), aggregate (95 parts by mass), and bubble nucleating agent (8 parts by mass) was mixed with an alkali metal silicate aqueous solution (alkali metal silicate: 77 parts by mass, water: 127 parts by mass) and stirred until a slurry was formed. A foaming agent (6 parts by mass) was then added to the slurry and stirred for 1 minute to prepare a foamable slurry for forming the geopolymer layer.

[0092] On the other hand, a synthetic resin foam board (polystyrene resin foam board (product name: Miraform Λ) manufactured by JSP Corporation) was placed in a 300 mm x 300 mm x 50 mm formwork, and an ethylene-vinyl acetate copolymer emulsion adhesive (product name: Nedatite manufactured by Konishi Corporation) was applied to the foam board. The thickness of the synthetic resin foam board was 25 mm, and the density was 35 kg / m 3 and 1m 2 The weight per unit is 0.9 kg, and the compressive strength (compressive stress at 10% strain) is 130 kN / m 2 It was. The foamable slurry was poured into a formwork, and the opening of the formwork was closed with a lid. The mixture was then cured at 60°C for 24 hours to allow the aluminosilicate and alkali metal silicate in the foamable slurry to react and foam. This resulted in the formation of a geopolymer layer, and the synthetic resin foam board and the geopolymer layer were bonded together with an adhesive. The geopolymer layer was then cut at its surface on the geopolymer layer side to achieve the desired thickness, resulting in a composite panel with the geopolymer layer's bubbles (cross section) exposed on the surface (300 mm x 300 mm) on the geopolymer layer side. The Al / Si molar ratio in the geopolymer structure of the geopolymer layer was 0.6. The aggregate content in the geopolymer layer was 34% by mass. The resulting composite panel had a top view area of ​​900 cm. 2 It was.

[0093] <Example 2> The composition of the geopolymer layer was the same as in Example 1, except that the amount of bubble nucleating agent added was 6 parts by mass and the amount of foaming agent added was 3 parts by mass. Example 3 The composition of the geopolymer layer was the same as in Example 1, except that the amount of bubble nucleating agent added was 6 parts by mass and the amount of foaming agent added was 4 parts by mass. Example 4 The composition of the geopolymer layer was the same as in Example 1, except that the amount of bubble nucleating agent added was 4 parts by mass. <Example 5> The thickness of the geopolymer layer was 10 mm, and the synthetic resin foam board was 30 mm thick and had a density of 34 kg / m 3 and 1m 2 The weight per unit is 1 kg, and the compressive strength (compressive stress at 10% strain) is 150 kN / m 2 The procedure was the same as in Example 1, except that a polystyrene-based resin foam board (manufactured by JSP Corporation (product name: Miraform Λ)) was used. Example 6 The composition of the geopolymer layer was the same as in Example 1, except that the amount of foaming agent added was 8 parts by mass. Example 7 The geopolymer layer was formulated in the same manner as in Example 1, except that the amount of foaming agent added was 12 parts by mass. <Comparative Example 1> The composition of the geopolymer layer was the same as in Example 1, except that the amount of bubble nucleating agent added was 0 parts by mass and the amount of foaming agent added was 0 parts by mass. <Comparative Example 2> The product of the thickness and density of the geopolymer layer is 4.5 kg / m 2 The same procedure as in Comparative Example 1 was followed except that the geopolymer layer was formed so that: <Comparative Example 3> The geopolymer layer was formulated in the same manner as in Example 1, except that the amount of foaming agent added was 1 part. <Comparative Example 4> The geopolymer layer was formulated in the same manner as in Example 1, except that the amount of foaming agent added was 20 parts by weight. <Comparative Example 5> The procedure was the same as in Example 1, except that the geopolymer layer was formed using a 300 mm × 300 mm × 40 mm formwork and the composite panel was produced without cutting the surface layer of the geopolymer layer. In this way, a composite panel having a geopolymer layer with a skin layer was obtained.

[0094] The various physical properties of the composite panels of Examples 1 to 7 and Comparative Examples 1 to 5 produced by the above methods are shown in Table 1. The various physical properties were measured by the following methods.

[0095] [density] The density of the geopolymer layer was determined by cutting out a geopolymer layer from the composite panel, dividing the weight of the cut-out geopolymer layer by the external dimensions of the cut-out geopolymer layer, and converting it into units.

[0096] [Average bubble diameter] The average bubble diameter of the geopolymer layer was determined by taking an image of a cross section along the thickness direction of the geopolymer layer, measuring the circular equivalent bubble diameter of each bubble in the image, and taking the arithmetic average of these. First, the geopolymer layer was cut along its thickness direction to expose the cross section at the center of the thickness direction of the geopolymer layer, creating a measurement sample. Next, image data of the exposed surface of the measurement sample was acquired using a measuring device (Keyence Corporation, Digital Microscope VHX-7000) (magnification: 20x). The area of ​​each bubble in the image was measured using the image processing software NS2K-pro (Nano Systems Co., Ltd.). This measurement was performed at five randomly selected locations in the geopolymer layer. The circular equivalent diameter of each bubble was calculated from the individual bubble areas obtained, and the arithmetic mean of these values ​​was used as the average bubble diameter. The circular equivalent diameter refers to the diameter of a circle with the same area as the bubble.

[0097] When measuring, bubbles present within the bubble walls are excluded from the calculation of the bubble diameter. Also, bubbles that are thought to have been removed from the bubble walls when the cross section of the geopolymer layer is exposed are also excluded from the calculation of the bubble diameter.

[0098] When acquiring image data, the following conditions are set. Monochrome conversion, smoothing filter (3x3, 8 neighbors, number of processes = 1) - Density unevenness correction (brighter than background, size=5) NS binarization (darker than background, clarity=9, sensitivity=1, noise removal, density range=0-255) Contraction (8 neighbors, number of processes = 1) Image selection by feature (area) (10000~∞μm 2 (select only 8 neighbors) - Disconnected expansion (8 neighbors, number of processes = 3) -Measure the equivalent diameter of each circle (calculated from the area, 8 neighbors)

[0099] [Thermal Conductivity (Insulation)] The thermal conductivity of the composite panel was measured using a thermal conductivity measuring device (HC-074-200) based on JIS A 1412-1:2016 (Thermal resistance and thermal conductivity of thermal insulation materials).The composite panel was kept at a constant temperature and humidity of 23°C and 50% for 24 hours before the thermal conductivity measurement.

[0100] Each composite panel used in the thermal conductivity measurements was kept at a high temperature and constant humidity of 23°C and 75% for 24 hours, and then kept at a constant temperature and humidity of 23°C and 50% for 12 hours. The thermal conductivity of the composite panel after moisture absorption and desorption was measured based on JIS A 1412-1:2016, and the measured value was taken as the thermal conductivity after moisture absorption and desorption.

[0101] Thickness The average thickness of the geopolymer layer was measured at five randomly selected locations on each of the four edges of the geopolymer layer. The arithmetic mean of the measured values ​​was taken as the average thickness of the geopolymer layer.

[0102] The average thickness of the composite panel was measured at five randomly selected measurement points on each of the four edges of the composite panel, and the arithmetic mean of the measured values ​​was taken as the average thickness of the composite panel.

[0103] [The product of the thickness of the geopolymer layer and the density of the geopolymer layer] The product of the thickness of the geopolymer layer and the density of the geopolymer layer (kg / m 2 ) was calculated by multiplying the average thickness of the geopolymer layer measured by the method described above by the density of the geopolymer layer and converting the result into units.

[0104] [Equilibrium volumetric water content] The equilibrium volumetric moisture content of the geopolymer layer was measured based on 5.1 desiccator method of JIS A 1475:2019. The measurements were performed on samples of 250 mm x 250 mm x geopolymer layer thickness cut out from the composite panels obtained in the examples and comparative examples.

[0105] An equilibrium moisture content curve was created from the equilibrium mass moisture content measured at five points between 20% and 93% relative humidity during the moisture absorption process of the sample. From this equilibrium moisture content curve, the equilibrium volumetric moisture content at 55% humidity was calculated.

[0106] In addition, equilibrium volume water content: ψ(m 3 / m 3 ) is the equilibrium mass moisture content of the sample at 55% humidity (kg / kg), ρ0 is the density of the sample at the standard dry state (kg / m 3 ), ρ w : Density of water at 23°C (997.6 kg / m 3 ) and ψ=u×ρ0 / ρ w It was calculated by:

[0107] [Moisture storage amount] The moisture storage capacity of composite panels was measured under medium humidity conditions in accordance with JIS A 1470-1:2014. Measurements were conducted on test specimens measuring 250 mm x 250 mm x composite panel thickness cut out from the composite panels obtained in the examples and comparative examples. The moisture storage capacity was calculated from the difference between the moisture absorption capacity at the end of the moisture absorption process and the moisture release capacity at the end of the moisture release process, as measured in accordance with Section 7 of JIS A 1470-1:2014, Moisture Absorption and Release Test Method.

[0108] [Amount of moisture absorbed at the end of the absorption process] Based on JIS A 1470-1:2014, the amount of moisture absorbed was measured after 12 hours at a relative humidity of 75%, which is the condition for the moisture absorption process (step 1) in the medium humidity range. The amount of moisture absorbed by the measured specimen after 12 hours of moisture absorption was divided by the moisture absorption and desorption area of ​​the specimen (250mm x 250mm), and this value was used as the amount of moisture absorbed at the end of the moisture absorption process (amount of moisture absorbed by the specimen per unit area at the end of the moisture absorption process).

[0109] [Amount of moisture released at the end of the moisture release process] Based on JIS A 1470-1:2014, the moisture release amount was measured after 12 hours at a relative humidity of 50%, which is the condition for the moisture release process (step 2) in the medium humidity range after going through the moisture absorption process (step 1) in the medium humidity range. The measured moisture release amount of the test specimen was divided by the moisture absorption and release area of ​​the test specimen (250mm x 250mm), and this value was used as the moisture release amount at the end of the moisture release process (moisture release amount of the test specimen per unit area at the end of the moisture release process).

[0110] [Fire resistance] The fire resistance test was conducted as follows. First, a test specimen measuring 30 cm long x 30 cm wide x composite panel thickness was placed in a heating furnace with the geopolymer layer facing the heat source. Next, the furnace was heated at the heating temperature of Standard Heating Curve A described in JIS A 1304:2017, Section 6, Test Conditions. After one hour of heating, the temperature of the back side of the geopolymer layer (the synthetic resin foam board layer side) was measured. For each test specimen, the temperature was measured at two points: one halfway along the length of the composite panel and one-quarter and three-quarters along the width of the composite panel. The arithmetic mean of these measurements was used as the backside temperature. Note that a lower backside temperature indicates less heat transfer during heating and better fire resistance.

[0111] The condition of the geopolymer layer after heating the test specimen for one hour was evaluated according to the following criteria. If no cracks or other defects occurred in the geopolymer layer after heating, and the shape of the geopolymer layer after heating did not change significantly from the shape of the geopolymer layer before heating, it can be said that the fire resistance was good.

[0112] [Geopolymer layer after heating] ○: No cracks were observed in the geopolymer layer after heating. △: Small cracks were observed in the geopolymer layer after heating. ×: Large cracks occurred in the geopolymer layer after heating, and the shape of the geopolymer layer before heating was not maintained.

[0113] [Adhesive strength] The adhesive strength between the synthetic resin foam board layer and the geopolymer layer was measured as follows.

[0114] First, a test piece measuring 5 cm long x 5 cm wide x the thickness of the composite panel was cut out from the composite panel. The surface of the test piece facing the geopolymer layer and the surface facing the synthetic resin foam board layer were then fixed to a tensile test jig with adhesive, and a tensile test was conducted.

[0115] The tensile test was performed in accordance with the JIS K6849:1994 method for testing the tensile bond strength of adhesives using a tabletop testing machine (autograph). A tensile load was applied perpendicular to the interface of the test specimen at a test speed of 2 mm / min, and the test was continued until adhesive failure (failure at the interface between the geopolymer layer or synthetic resin foam board layer and the adhesive), cohesive failure (failure within the adhesive), or adherend failure (failure within the geopolymer layer or synthetic resin foam board layer) occurred.

[0116] The tensile adhesive strength was calculated from the relationship between the maximum load measured in the tensile test and the adhesive area, and this was taken as the adhesive strength.

[0117] [Condensation evaluation] The susceptibility of the composite panels to condensation was evaluated as follows:

[0118] First, the composite panel was left to stand for 24 hours in an environment with an air temperature of -10°C. Next, the cooled composite panel was placed in a constant temperature and humidity chamber with an air temperature of 20°C and a relative humidity of approximately 50%, and the occurrence of condensation on the geopolymer layer side was checked after one hour.

[0119] If water droplets with a diameter of 1 mm or more were present on the surface of the geopolymer layer, they were rated as "large droplets," if water droplets with a diameter of less than 1 mm were present, they were rated as "small droplets," and if no water droplets were observed, they were rated as "none." Of these evaluations, those rated as "none" were considered to be composite panels in which condensation was suppressed.

[0120] [Table 1]

[0121] As shown in Table 1, in Examples 1-7, the geopolymer layer of the composite panel had an equilibrium volumetric moisture content of 5×10 at 55% humidity, as measured in accordance with JIS A 1475:2019. -3 m 3 / m 3 or more, and the moisture storage capacity in the medium humidity range measured based on JIS A 1470-1:2014 is 25 g / m 2 The following values ​​are included (including 0). It was confirmed that Examples 1-7 were less susceptible to condensation. The reason why Examples 1-7 were less susceptible to condensation is thought to be that the equilibrium volumetric moisture content was above a specific value and the geopolymer layer had a moisture storage capacity below a specific value, which made it easier for moisture to accumulate within the geopolymer layer. In addition, the composite panels of Examples 1-7 were excellent in fire resistance and heat insulation.

[0122] On the other hand, the composite panel of Comparative Example 1-5 was prone to condensation.

[0123] Specifically, in the composite panels of Comparative Examples 1, 3, and 5, the moisture storage capacity of the geopolymer layer was excessively large, making it difficult to store moisture within the geopolymer layer, which is thought to have made condensation more likely to occur.

[0124] In the composite panel of Comparative Example 2, the geopolymer layer is not foamed (the geopolymer layer is not foamed and does not contain many air bubbles), which is thought to make it difficult for moisture to accumulate within the geopolymer layer, making condensation more likely to occur.In addition, it was confirmed that the fire resistance of the composite panel of Comparative Example 2 was reduced.

[0125] In the composite panel of Comparative Example 4, the equilibrium volumetric moisture content was excessively low, and the amount of moisture absorbed by the geopolymer layer itself was small, which is thought to have made condensation more likely to occur.

[0126] Furthermore, it was confirmed that the composite panel of Comparative Example 1-5 had high thermal conductivity after moisture absorption and desorption, and that the state of reduced heat insulating properties (state of high thermal conductivity) tended to continue after moisture absorption. [Explanation of symbols]

[0127] 1. Synthetic resin foam board layer 2 Geopolymer Layer P composite panel

Claims

1. A composite panel comprising a synthetic resin foam board layer and a geopolymer layer, The geopolymer layer contains a large number of bubbles formed by foaming, The equilibrium volumetric moisture content of the geopolymer layer at a humidity of 55%, as measured based on JIS A 1475:2019, is 5 x 10 -３ m ３ / m ３ That's all, The moisture storage capacity of the geopolymer layer in a medium humidity range measured based on JIS A 1470-1:2014 is 25 g / m ２ A composite panel that is:

2. The product of the thickness of the geopolymer layer and the density of the geopolymer layer is 2 to 10 kg / m ２ 2. The composite panel of claim 1, wherein:

3. The density of the geopolymer layer is 150 to 700 kg / m ３ 3. The composite panel according to claim 1 or 2, wherein:

4. The composite panel according to claim 1 or 2, wherein the average bubble diameter of the geopolymer layer is 0.1 to 5 mm.

5. The area of ​​the composite panel in a top view is 500 cm ２ The composite panel according to claim 1 or 2, wherein:

6. The adhesive strength between the geopolymer layer and the synthetic resin foam board layer is 5 N / cm ２ The composite panel according to claim 1 or 2, wherein:

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