Structural material

Abstract

To provide a structural material of a resin foam base material which has a hard metal surface irrespective of a surface shape, is lightweight and has flame retardancy.SOLUTION: A structural material 20 has a sprayed metal layer 22 on the surface of a base material 21 composed of a resin foam subjected to flame-retardant treatment. The base material 21 is composed of a flame-retardant resin foam foam-molded by foamable resin beads coated with a flame retardant. The sprayed metal layer 22 contains an aluminum alloy. A resin undercoat 23 is provided on the surface of the base material 21, and the sprayed metal layer 22 is formed on the resin undercoat 23.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a structural material formed of a resin foam and having a metal surface. [Background technology]

[0002] Resin foams such as urethane and polystyrene have low thermal conductivity and exhibit high insulating properties, so they are often used for wall and ceiling materials, and many panels with a resin foam base are also available.

[0003] Here, there is a technique relating to a panel in which aluminum alloy foil is bonded to the surface of a flame-retardant phenolic resin-modified expanded polystyrene board (Patent Document 1).

[0004] There is also a technology relating to structural materials such as building materials in which a foam containing an inorganic filler as a base material is formed on the surface of which a metal coating layer is formed by metal spraying (Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Utility Model Registration No. 3217042 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-240971 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in structural materials in which aluminum alloy foil is attached to the surface of a foamed resin substrate with an adhesive, the metal surface is prone to scratches and wrinkles due to the thinness of the aluminum alloy foil. Furthermore, when the substrate surface is not flat but has a three-dimensional shape with irregularities, it is difficult to properly attach the aluminum alloy foil to the three-dimensional surface, and the metal surface is prone to scratches and wrinkles, which impairs the aesthetic appearance.

[0007] Furthermore, when a metal coating is applied to the surface of a three-dimensional resin foam substrate, the heat generated during metal spraying can affect the foam.

[0008] The present invention has been made in consideration of these circumstances, and can provide a structural material with a resin foam substrate that has a hard metal surface regardless of the surface shape, is lightweight, and is flame-retardant. [Means for solving the problem]

[0009] In order to solve the above problems, the structural material of the present invention is characterized in that it has a metal sprayed layer on the surface of a substrate made of a flame-retardant treated resin foam, one or more layers of resin undercoat are provided on the surface of the substrate, and the metal sprayed layer is formed on the resin undercoat.

[0010] The structural material is also characterized in that the base material is made of a flame-retardant resin foam obtained by foam molding expandable resin beads coated with a flame retardant.

[0011] Furthermore, in the structural material, the metal sprayed layer contains an aluminum alloy. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a structural material having a resin foam substrate that has a hard metal surface regardless of the surface shape, and that is lightweight and flame-retardant. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view of a structural material according to a first embodiment of the present invention. [Figure 2] FIG. 4 is a cross-sectional view of a structural material according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] A structural material according to one embodiment of the present invention will be described below with reference to the drawings. The structural material according to the present invention has a structure in which a metal sprayed layer is formed by spraying metal onto the surface of a base material made of a flame-retardant treated resin foam.

[0015] <Structural material 10 according to the first embodiment> 1 is a cross-sectional view of a structural material 10 according to a first embodiment of the present invention. The structural material 10 is formed from a substrate 11 made of a flame-retardant resin foam, and is provided with a metal sprayed layer 12 formed on the surface of the substrate 11 by metal spraying.

[0016] In the structural material 10 shown in Figure 1, the metal sprayed layer 12 is formed on both the front side (the surface on the upper side in Figure 1) and the back side (the surface on the lower side in Figure 1) of the substrate 11, but it does not necessarily have to be formed on both sides. For example, if the structural material 10 is used as a ceiling or wall material, the metal sprayed layer 12 may be formed only on the indoor side, such as on the side facing a heat source expected in the event of a fire. Furthermore, the thickness of each metal sprayed layer may be different, such as by making the metal sprayed layer 12 thicker on the front side of the substrate 11 than on the back side.

[0017] The substrate 11 is composed of a flame-retardant resin foam obtained by expansion molding expandable resin beads coated with a flame retardant. For example, expandable styrene resin raw material is pre-expanded to produce pre-expanded styrene resin beads. The surfaces of the pre-expanded styrene resin beads are then coated with a flame retardant or the like to produce flame-retardant expandable resin beads. The flame-retardant-coated expandable resin beads are then expansion-molded to obtain the substrate 11. If the flame-retardant substrate 11 thus produced encounters a fire, the coating layer is carbonized without burning, and the expandable resin beads instantly melt and burn, forming cavities. The carbonized coating layer and the cavities in the beads act as a shield against fire and high heat, blocking the progression of combustion of the substrate 11.

[0018] In this embodiment, the base material 11 is "Varishield (registered trademark)" (manufactured by Ushiomatex Inc.), a highly flame-retardant, lightweight, and highly insulating material made by specially coating a foamable styrene resin raw material with a flame retardant, etc., and then foam-molding it.

[0019] The metal sprayed layer 12 is formed by spraying, for example, a metal containing an aluminum alloy. Examples of methods that can be used for metal spraying include arc spraying using electricity on the substrate 11 (a method in which arc discharge is generated using two metal wires as electrodes, and molten atomized metal particles are sprayed onto the substrate 11 with high-velocity air, thereby forming a dense metal coating on the surface of the substrate 11), and other spraying methods (for example, gas spraying, plasma spraying, etc.).

[0020] When forming the metal sprayed layer 12, it is necessary to appropriately consider the film thickness and metal density of the metal sprayed layer 12. Therefore, when designing and manufacturing the structural material 10, the film thickness and metal density of the metal sprayed layer 12 are controlled so that the non-combustibility performance satisfies the required level.

[0021] 1, a resin undercoat 13 is provided on the surface of a substrate 11, and a metal sprayed layer 12 is formed on the surface of the resin undercoat 13. This strengthens the mechanical bond between the substrate 11 and the metal sprayed layer 12. This effectively prevents the metal sprayed layer 12 from peeling off or cracking from the substrate 11.

[0022] Examples of materials that can be used for the resin undercoat 13 include silicone-based resins, urea-based resins, and urethane-based resins, which are non-reactive with the expandable styrene resin and have high heat resistance. The resin undercoat 13 may be a single layer or multiple layers. By providing such a resin undercoat 13, a hard metal sprayed layer can be formed on a lightweight, flame-retardant structural material made of a resin foam substrate.

[0023] <Structural Material 20 According to Second Example> 2 is a cross-sectional view of a structural material 20 according to a second embodiment of the present invention. The structural material 20 is formed from a substrate 21 made of a flame-retardant treated resin foam, and is provided with a metal sprayed layer 22 formed by metal spraying on the surface of the substrate 21. The substrate 21 uses the same resin foam as the substrate 11 of the structural material 10 in the first embodiment described above. The metal sprayed layer 22 also uses the same metal as the metal sprayed layer 12 of the structural material 10 described above. Furthermore, the resin undercoat 23 also uses the same resin as the resin undercoat 13 of the structural material 10 described above.

[0024] In the structural material 20 shown in Figure 2, the base material 21 has a cylindrical member 21A, a cylindrical member 21B having an approximately truncated cone shape formed concentrically on the front surface (the upper surface in Figure 2), and a cylindrical member 21C having an even smaller diameter concentrically formed on member 21B, forming a three-dimensional structure in which two-stage convex members are formed on the cylindrical member.

[0025] For convenience, the substrate 21 is illustrated and described as being divided into three members (member 21A, member 21B, and member 21C), but in reality, these three members are integrally formed, and are not integrated by adhesive or the like. For example, a molded product may be cut and NC processed to produce the final shape shown in FIG.

[0026] 2, no metal sprayed layer is formed on the backside (the surface on the lower side in FIG. 2) of the substrate 21, but this is because the metal sprayed layer is formed on only one side in order to measure the characteristics of the structural material 20, and a metal sprayed layer may be formed on both sides. Also, the thickness of the metal sprayed layer on the front side and the back side of the substrate 21 may be different.

[0027] 2 is configured to have a three-dimensional surface with two truncated cone members 21B and 21C of different sizes formed on a cylindrical member 21A, but this is just one example of a three-dimensional shape and does not particularly limit the type of three-dimensional shape. For example, the boundaries between the top and side surfaces of the truncated cones of member 21B and member 21C may be rounded, making both members approximately truncated cone shaped.

[0028] <Combustion test> A combustion test was conducted under the same conditions for structural material 20 according to the second embodiment of the present invention and a conventional structural material in which aluminum alloy foil is bonded to the surface of a flame-retardant resin foam substrate. Table 1 shows the results of the comparison of the combustion test between structural material 20 according to the second embodiment of the present invention and the conventional product.

[0029] [Table 1]

[0030] The flame retardancy level was assessed using a "cone calorimeter heat generation test," which is used to evaluate non-combustible materials under the Building Standards Act. Specifically, the test measures how long the following conditions are met after heating: (1) total heat generation is 8 MJ / m² or less, (2) the maximum heat generation rate does not exceed 200 kW / m² continuously for more than 10 seconds, and (3) there are no cracks or holes penetrating to the backside that are harmful to fire safety. As a result, structural material 20 met the heating time of 20 minutes or more and other requirements, achieving a quality equivalent to a "non-combustible material" in the evaluation of non-combustible materials under the Building Standards Act. Furthermore, the density and film thickness of the metal coating can be controlled (selected appropriately) to increase or decrease the flame retardancy level depending on the design requirements of the structural material.

[0031] As described above, the structural material 20 according to the present invention has a multilayer structure including a flame-retardant resin foam, and can be applied to three-dimensional substrates having an uneven surface due to the formation of a metal layer by metal spraying. Furthermore, the exterior of the structural material 20 may be polished to improve specular reflectance and aesthetics, while taking into consideration the reduction in flame retardancy due to a reduction in layer thickness caused by polishing.

[0032] In addition, in order to achieve flame retardancy for the resin foam used in the substrate, in addition to the materials mentioned above, highly flame-retardant resins such as phenol and PVC (polyvinyl chloride) may be used, and various resins that have been treated with flame-retardant formulations, such as urethane, ABS, polyolefin, and polystyrene, can also be used as the substrate.

[0033] Furthermore, since the structural material according to the present invention is coated with a metal spray layer, it can ensure higher flame retardancy than a resin foam base material alone. Furthermore, by forming a resin undercoat, it is possible to ensure higher adhesion between the metal layer and the resin foam and higher flame retardancy.

[0034] As described above, the structural material 20 according to the present invention has a hard metal sprayed layer formed on its surface, making it lightweight and flame-retardant overall. The surface metal layer provides aesthetic appeal and durability, making it suitable for use as a structural material, such as building materials. The rigidity of structural components can also be increased by increasing the amount of metal coating (basis weight). For example, arc spraying is preferred because it provides a fast formation rate for the metal sprayed layer 21 and allows for precise control of the basis weight of the metal sprayed layer 21. Metals used in metal spraying include not only aluminum alloys, but also zinc, copper, and alloys of these metals with aluminum.

[0035] Furthermore, since the structural material according to this embodiment has a metal sprayed layer on its surface, it can be used on substrates with uneven three-dimensional surfaces, and the metal spraying is performed after forming the uneven surface of the substrate. Therefore, no processing is required after the metal spraying, and there is no need to press or bend the structural material, so the non-combustibility and flame retardancy are not reduced by cracks in the metal sprayed layer. [Explanation of symbols]

[0036] 10, 20 Structural materials 11, 21 Resin foam 12, 22 Metal sprayed layer 13, 23 Resin undercoat 21A, 21B, 21C parts

Claims

1. A metal sprayed layer is formed on the surface of a base material made of a flame-retardant treated resin foam, One or more layers of resin undercoat are provided on the surface of the substrate, and the metal spray layer is formed on the resin undercoat. A structural material characterized by:

2. 2. The structural material according to claim 1, wherein the substrate is made of a flame-retardant resin foam obtained by foam molding expandable resin beads coated with a flame retardant.

3. 3. The structural material according to claim 1, wherein the metal sprayed layer contains an aluminum alloy.

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