Coating composition and sheet molding

Abstract

To provide a coating composition and a sheet-like molding which can render wood flame-retardant with its grains visible.SOLUTION: A coating composition contains sodium silicate. In the sodium silicate, the molar ratio of SiO2 / Na2O is 1.8-3.0 as defined in JIS K 1408: 1966. A sheet-like molding is designed to render wood flame-retardant with its grains visible. The sheet-like molding contains sodium silicate. In the sodium silicate, the molar ratio of SiO2 / Na2O is 1.8-3.0 as defined in JIS K 1408: 1966.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coating composition and a sheet molding. [Background technology]

[0002] Methods for making wood flame-retardant while still allowing the wood grain to be seen include a method of impregnating the wood with a flame retardant (see, for example, Patent Document 1), a method of impregnating the wood with water-soluble sodium silicate and water-soluble biomass nanofibers (see, for example, Patent Document 2), and a method of applying a composition in which sodium silicate or phenolic resin is used as a base material and one or more types of glass balloons, shirasu balloons, non-flammable wood flour, and aluminum powder are kneaded together (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-137805 [Patent Document 2] Patent Publication No. 2021-17912 [Patent Document 3] Patent Publication No. 2021-66859 Summary of the Invention [Problem to be solved by the invention]

[0004] The method of impregnating wood with a flame retardant requires special equipment and is time- and energy-intensive.

[0005] The method of making wood flame-retardant by impregnating it with water-soluble sodium silicate and water-soluble biomass nanofibers has low transparency, making the wood grain invisible. In addition, it requires the use of fire-retardant wood or non-combustible materials, and the flame retardancy is insufficient to satisfy the interior restrictions of the Building Standards Act.

[0006] The composition, which is based on sodium silicate or phenolic resin and is kneaded with one or more types of glass balloons, shirasu balloons, non-flammable wood flour, and aluminum powder, is opaque and the wood grain cannot be seen when applied to wood.

[0007] It is thought that applying a coating composition to wood to form a coating layer can make wood flame-retardant while still allowing the wood grain to be seen. When heated, the coating layer vitrifies and becomes an oxygen-blocking layer.

[0008] By applying the sheet-shaped molding to wood as a coating layer, it is possible to make the wood flame-retardant while still allowing the wood grain to be seen. When heated, the coating layer vitrifies and becomes an oxygen-blocking layer. [Means for solving the problem]

[0009] One aspect of the present disclosure is a coating composition that makes wood flame retardant while allowing the wood grain to be visible, the coating composition containing sodium silicate, wherein the sodium silicate has a SiO2 / Na2O molar ratio, as defined in JIS K 1408:1966, of 1.8 to 3.0.

[0010] Another aspect of the present disclosure is a sheet-like molded product that makes wood flame-retardant while allowing the wood grain to be visible, the sheet-like molded product containing sodium silicate, the sodium silicate having a SiO2 / Na2O molar ratio, as defined in JIS K 1408:1966, of 1.8 to 3.0. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing a structure in which a coating film or a sheet-shaped molding of the coating composition of the present invention is provided on a wood surface. [Figure 2] FIG. 10 is a cross-sectional view illustrating another example. [Figure 3] FIG. 10 is a cross-sectional view illustrating another example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Exemplary embodiments of the present disclosure will now be described with reference to the drawings. 1.Paint composition The coating composition of the present disclosure contains sodium silicate having a SiO2 / Na2O molar ratio of 1.8 to 3.0 as specified in JIS K 1408:1966. The molar ratio is more preferably 1.8 to 2.6. If the molar ratio is less than 1.8, the coating composition becomes unstable, and conversely, if it exceeds 3.0, the coating film formed by the coating composition will not have sufficient flexibility.

[0013] The coating composition of the present disclosure can be applied to the surface of wood to form a transparent coating film. In this specification, "transparent" refers to a state in which the wood grain can be seen, and is not limited to complete transparency, and may be, for example, semi-transparent.

[0014] The content of sodium silicate in the nonvolatile matter of the coating composition of the present disclosure is preferably 75 to 100 mass %, more preferably 85 to 100 mass %, which provides an excellent effect of making wood flame retardant and excellent visibility of the wood grain.

[0015] The nonvolatile content of the coating composition of the present disclosure is preferably 40 to 65 mass %, more preferably 50 to 60 mass %. When it is in this range, the coating workability of the coating composition is excellent.

[0016] The coating composition of the present disclosure further contains, for example, glass fiber. When the coating composition contains glass fiber, cracking of the coating film is suppressed. The diameter of the glass fiber is preferably 2 μm or more and 15 μm or less. The length of the glass fiber is preferably 3 μm or more and 200 μm or less, and more preferably 5 μm or more and 50 μm or less. The value obtained by dividing the length of the glass fiber by the diameter of the glass fiber is the aspect ratio of the glass fiber. The aspect ratio of the glass fiber is preferably 1.5 or more and 5.5 or less.

[0017] The coating composition of the present disclosure can contain additives, pigments, etc. that are used in ordinary coatings, to the extent that the flame retardancy and transparency of the coating film are not significantly impaired. Examples of additives include thickeners, pH adjusters, UV absorbers, dispersants, wetting agents, preservatives, dyes, antifoaming agents, pigments, etc.

[0018] Examples of thickeners include clay minerals such as organically modified smectite, silica, etc. Examples of pH adjusters include ammonia water, sodium hydroxide, etc. Examples of pigments include inorganic pigments, organic pigments, extender pigments, etc. Examples of inorganic pigments include carbon black, titanium oxide, iron oxide, etc. Examples of organic pigments include quinacridone, azo pigments, etc. Examples of extender pigments include barium sulfate, talc, mica, etc.

[0019] The coating composition of the present disclosure can be produced, for example, as follows. After placing sodium silicate in a paint manufacturing vessel, the additives, pigments, etc. are added while stirring with a mixer to obtain a uniform solution. Dilution with water may be performed to adjust the viscosity.

[0020] The coating composition of the present disclosure can be used, for example, as follows. The wood may be, for example, cedar lumber having a thickness of 12 mm, a width of 105 mm, and a length of 2000 mm. The coating composition may be applied using a brush or a roller. The amount of coating composition applied is, for example, 2.3 kg / m2.

[0021] After the first application, the surface is left at room temperature for 16 hours. Next, the coating composition is applied again. This application is the second application. The application method and amount of coating for the second application are the same as for the first application. After the second application, the surface is left at room temperature for 16 hours. Alternatively, two coats of coating may be applied in one application. The coating film obtained in this way is transparent, allowing the wood grain to be seen.

[0022] Next, a matte paint containing an acrylic resin emulsion may be applied as a transparent resin layer using an air spray. The amount of matte paint applied is, for example, 100 g / m². The product is left at room temperature for 16 hours. Through these steps, a flame-retardant wooden building material can be obtained.

[0023] The wood is not limited to cedar lumber, and various wood building materials can be selected as desired. Examples of wood building materials include lumber, laminated lumber, plywood, laminated veneer lumber (LVL), cross-laminated timber (CLT), medium-density fiberboard (MDF), and veneer. The form of the wood is not particularly limited. Examples of the form of the wood include pillars, boards, sheets, and cloth.

[0024] The type of wood is not limited to cedar, and various woods can be selected as desired, such as cypress, larch, Scots pine, and Japanese cypress.

[0025] Furthermore, examples of uses of wooden building materials include wooden structural members, such as pillars, beams, walls, and floors.

[0026] The pillar may be, for example, a rectangular pillar. The cross-sectional shape of the rectangular pillar in a cross section perpendicular to the longitudinal direction is, for example, a square. The length of one side of the square is, for example, 90 mm or more and 1100 mm or less.

[0027] An example of a beam is a rectangular beam. The cross-sectional shape of a rectangular beam in a cross section perpendicular to the longitudinal direction is, for example, a rectangle. The length of one side of the rectangle is, for example, 90 mm or more and 800 mm or less. The length of the side adjacent to the one side is, for example, 90 mm or more and 1200 mm or less. The length of the rectangular beam is not particularly limited, but is, for example, 3000 mm or more and 10000 mm or less.

[0028] The shape of the wall is, for example, a rectangle. The length of the short side of the rectangle is, for example, 3000 mm or less. The length of the short side of the rectangle is, for example, 500 mm or more. The length of the long side of the rectangle is, for example, 12000 mm or less. The length of the long side of the rectangle is, for example, 2000 mm or more.

[0029] Examples of wood include board- or sheet-shaped wood attached to the surface of inorganic building materials such as gypsum boards.

[0030] The tool used to apply the coating composition may be a tool other than a roller. As the tool used to apply the coating composition, a tool used to apply a normal coating can be used. Examples of the tool used to apply the coating composition include a brush, a spatula, a spray, a roll coater, a knife coater, etc.

[0031] The coating amount of the coating composition can be set arbitrarily depending on the required flame retardancy. For example, to keep the total heat generated when cedar lumber is heated for 10 minutes at a radiation intensity of 50 kW / m2 according to the cone calorimeter method specified in ISO 5660-1 to 8 MJ / m2 or less, the coating amount is preferably 1.5 kg / m2 to 3.0 kg / m2, and more preferably 1.8 g / m2 to 2.6 g / m2.

[0032] After application of the coating composition, the drying temperature is preferably 80°C or lower. When forced drying is performed, the drying temperature is 35°C to 70°C, more preferably 45 to 60°C. When the temperature is within this range, deformation of the wood to which the coating composition is applied can be suppressed. Natural drying may be performed instead of forced drying.

[0033] The drying time after application of the coating composition can be shortened or extended as necessary. The time left at room temperature before forced drying is preferably 30 minutes to 24 hours, more preferably 1 hour to 16 hours. When the drying temperature in forced drying is 60°C or lower, forced drying may be performed immediately after application without leaving it at room temperature.

[0034] The transparent resin layer is not limited to a matte paint, and may be any transparent synthetic resin, such as a synthetic resin film.

[0035] Instead of the transparent resin layer, a glass plate may be attached. The purpose of applying a matte paint is to impart a design. Paint intended to impart a design is called a decorative paint. In decorative paint, a glossy paint may be used instead of a matte paint. In decorative paint, paints that do not significantly impair the visibility of the substrate can be appropriately selected and used, not limited to paints containing acrylic resin emulsions.

[0036] The paint used in the decorative coating may be a paint containing a synthetic resin solution or a synthetic resin aqueous solution instead of a synthetic resin emulsion. The paint used in the decorative coating is not limited to acrylic resin, and may be a paint containing any synthetic resin such as urethane resin, epoxy resin, vinyl acetate resin, or olefin resin. A commercially available clear paint may be used in the decorative coating. Decorative coating does not have to be performed.

[0037] When the coating composition of the present disclosure is applied to the surface of a substrate, the flame retardancy of the substrate increases. The reason for this is presumed to be as follows.

[0038] When wood coated with the coating composition of the present disclosure and then coated with a decorative coating is exposed to the heat of combustion during a fire, the coating film of the decorative coating on the outermost surface burns within a few seconds to several tens of seconds. Next, the coating film of the coating composition of the present disclosure begins to vitrify, forming an oxygen-blocking layer. As a result, the wood does not burn and generates almost no heat.

[0039] 2. Sheet-shaped moldings The sheet-form product of the present disclosure contains sodium silicate having a SiO2 / Na2O molar ratio of 1.8 to 3.0 as defined in JIS K 1408:1966. The SiO2 / Na2O molar ratio is more preferably 2.0 to 2.6. If the molar ratio is less than 1.8, it becomes difficult to form the product into a sheet, and conversely, if it exceeds 3.0, the flexibility of the sheet-form product is insufficient.

[0040] The content of sodium silicate in the sheet-form molded product of the present disclosure is preferably 75 to 100 mass %, more preferably 85 to 100 mass %, which provides an excellent effect of making wood flame-retardant and excellent visibility of the wood grain.

[0041] The sheet-like molded product of the present disclosure further contains, for example, glass fibers. When the sheet-like molded product contains glass fibers, cracking of the sheet-like molded product is suppressed and the sheet is less likely to tear when handled during the manufacturing process or at a construction site, etc. The diameter of the glass fibers is preferably 2 μm or more and 15 μm or less. The length of the glass fibers is preferably 3 μm or more and 200 μm or less, and more preferably 5 μm or more and 50 μm or less. The value obtained by dividing the length of the glass fibers by the diameter of the glass fibers is the aspect ratio of the glass fibers. The aspect ratio of the glass fibers is preferably 1.5 or more and 5.5 or less.

[0042] The sheet-form molded product of the present disclosure may contain, for example, conventional additives, pigments, etc., to the extent that the flame retardancy and transparency of the coating film are not significantly impaired. Examples of additives include thickeners, ultraviolet absorbers, dispersants, wetting agents, dyes, antifoaming agents, pigments, etc.

[0043] Examples of thickeners include clay minerals such as organically modified smectite, silica, etc. Examples of pigments include inorganic pigments, organic pigments, and extender pigments, etc. Examples of inorganic pigments include carbon black, titanium oxide, and iron oxide, etc. Examples of organic pigments include quinacridone and azo pigments, etc. Examples of extender pigments include barium sulfate, talc, mica, and antimony trioxide, etc.

[0044] The method for producing the sheet-form molded product of the present disclosure is, for example, as follows. While kneading sodium silicate in a mixer, the additives, pigments, etc. are added to form a uniform clay-like or viscous solution (such a clay-like or viscous solution-like sodium silicate-containing composition before being formed into a sheet shape will hereinafter be referred to as a "sheet intermediate").

[0045] Subsequently, the sheet intermediate is extruded by an extruder through a mold of a predetermined width and thickness onto a PET synthetic resin film as a transparent resin layer, and then dried and wound up to obtain a transparent sheet-like molded product.

[0046] The sodium silicate used in the sheet intermediate preferably has a heavy Baume coefficient at 15° C. as specified in JIS K 1408:1966 of 45 to 80. When the heavy Baume coefficient is within this range, excellent moldability of the sheet-shaped product is obtained.

[0047] The sheet intermediate is preferably clay-like. It may be liquid, but it preferably has a higher viscosity and lower fluidity than the coating composition. By having the sheet intermediate be clay-like, it has excellent moldability.

[0048] The nonvolatile content of the sheet intermediate is preferably 75 to 99 mass %, more preferably 80 to 95 mass %. When the nonvolatile content is in this range, excellent moldability of the sheet-form molded product is obtained.

[0049] The sheet-shaped composition has a width of, for example, 1000 mm and a thickness of, for example, 1.5 mm.

[0050] The molding method is not limited to the use of an extruder, and for example, the sheet intermediate may be poured into a mold to be molded, or the sheet intermediate may be pressed to be molded.

[0051] The forming method is not limited to the winding method, but may be a sheet-like method. The synthetic resin film can be a transparent synthetic resin film such as PET, polyethylene, polypropylene, or polyvinyl alcohol. The surface of the separator may be subjected to a release treatment using a silicone resin or the like. Depending on the molding method, the use of a release agent or the like can prevent the sheet intermediate from adhering to the manufacturing equipment, and in such cases, a synthetic resin film may not be used.

[0052] The transparent resin layer is preferably permeable to water vapor, which accelerates the drying of the sheet intermediate and improves the productivity of the sheet-shaped composition.

[0053] The transparent resin layer may be provided on both sides of the sheet intermediate. In this configuration, the surface on which the sheet intermediate extruded from the extruder is placed may be a synthetic resin film, and the other surface may be a decorative coating. This allows the design to be imparted all at once during the production process, and since the decorative coating has higher water vapor permeability than a synthetic resin film, the sheet intermediate dries faster, resulting in excellent productivity for the sheet composition.

[0054] The thickness of the transparent resin layer is preferably 15 to 150 μm, more preferably 20 to 50 μm. When it is in this range, the amount of heat generated can be suppressed, resulting in excellent flame retardancy.

[0055] The synthetic resin film may be adhered to the sheet intermediate without being peeled off. In this case, the sheet composition can be installed on a building material without peeling off the transparent resin layer, which is excellent in productivity and also functions as a protective layer that provides water resistance, prevents scratches, maintains aesthetic appearance, etc.

[0056] When the synthetic resin film is adhered to the sheet intermediate, the adhesion between the transparent resin layer and the sheet intermediate can be improved by applying a primer or the like to the surface where the transparent resin layer and the sheet intermediate come into contact, or by subjecting them to plasma treatment.

[0057] When the synthetic resin film is adhered to the sheet intermediate, a release treatment can be applied to the surface that does not come into contact with the transparent resin layer and the sheet intermediate. In this configuration, the wound sheet-like molded product can be easily unrolled at a construction site or a building material factory.

[0058] When the synthetic resin film is brought into close contact with the sheet intermediate, it is preferable to provide a matte finish by embossing the surface that is not in contact with the transparent resin layer and the sheet intermediate, etc. When configured in this manner, it is possible to diffuse the reflection of light from indoor lighting, resulting in excellent design properties.

[0059] When the synthetic resin film is adhered to the sheet intermediate, an adhesive layer may be provided on the side of the transparent resin layer that is not in contact with the sheet intermediate, which makes it easier to fix the sheet-like molded product to the surface of wood at a construction site or a building material factory.

[0060] A glass plate may be used in place of the synthetic resin film. The drying temperature when drying the sheet intermediate is preferably 150°C or less. When forced drying is performed, the drying temperature can be ramped to gradually volatilize the moisture from the entrance of the drying oven until the maximum temperature is reached, thereby suppressing the generation of bubbles due to the sudden evaporation of moisture. Natural drying may be performed instead of forced drying.

[0061] The drying time for the sheet intermediate can be shortened or extended as required. Before forced drying, the sheet intermediate may be left to stand at room temperature.

[0062] The moisture content of the sheet-form molded product is preferably 1 to 10% by mass, and more preferably 3 to 8% by mass.

[0063] In the above embodiment, the sheet intermediate is extruded to form the sheet, but the coating composition may be poured into a mold or the like and dried to form the sheet.

[0064] The sheet-shaped molded article of the present disclosure can be used, for example, as follows. The sheet-like molded product of the present disclosure is attached to the surface of wood by screws or the like. The wood may be, for example, cedar CLT with a thickness of 90 mm, a width of 600 mm, and a length of 3500 mm. The thickness of the sheet-like molding is, for example, 1.2 mm.

[0065] The method for fixing the sheet-like molding is not limited to screw fastening, and may be, for example, adhesive bonding, adhesion, gripping with metal, etc. Another example is a method in which the surface of the sheet-like molding not having the transparent resin layer is wetted with water and then pressed against wood.

[0066] The width of the sheet-like molding can be set arbitrarily depending on the size of the required building material, and examples include 300 mm, 303 mm, 910 mm, 1000 mm, and 2000 mm.

[0067] The thickness of the sheet-shaped molding can be set arbitrarily depending on the required flame retardancy. For example, to keep the total heat generated when cedar CLT is heated for 10 minutes at a radiation intensity of 50 kW / m2 according to the cone calorimeter method specified in ISO 5660-1 to 8 MJ / m2 or less, the thickness is preferably 0.5 to 2.0 mm, and more preferably 0.7 to 1.5 mm.

[0068] The wood is not limited to cedar CLT, and various wood building materials can be selected as desired, such as those listed above in the section "2. Composition of the coating composition."

[0069] The uses and shapes of wooden building materials are also as listed above in the section "2. Composition of the coating composition."

[0070] After the sheet-like molding is fixed to the wood, a matte coating may be applied to the surface of the sheet-like molding. Furthermore, if the transparent resin layer is not to be peeled off, a similar design can be achieved by using a matte synthetic resin film. The reason for using a matte coating or a matte synthetic resin film is to provide a design. In such a decorative coating or decorative separator, a glossy coating or a glossy synthetic resin film may be used instead of the matte coating or matte synthetic resin film. In a decorative coating or decorative separator, a coating or a synthetic resin film that does not significantly impair the visibility of the substrate can be appropriately selected and used. By using a decorative coating or a decorative synthetic resin film, the sheet-like molding has excellent water resistance, scratch resistance, and aesthetic appearance.

[0071] When the sheet-like molded product is fixed to wood, it may be fixed with the transparent resin layer facing the wood.

[0072] The transparent resin layer may be provided on one side or both sides of the sheet-like molded product. By providing a transparent resin layer on at least one side of the sheet-like molded product, the sheet-like molded product can be easily handled at construction sites or building material factories. Furthermore, by providing a transparent resin layer on both sides, the sheet-like molded product has excellent crack prevention properties.

[0073] When wood to which the sheet-like molding of the present disclosure is fixed is subjected to the heat of combustion during a fire, the outermost transparent resin layer burns all at once, followed by the initiation of vitrification of the sheet-like molding, forming an oxygen-blocking layer, which prevents the wood from burning and suppresses heat generation.

[0074] The effects of the present invention will be explained below with reference to examples and comparative examples. Unless otherwise specified, the SiO2 / Na2O molar ratio of sodium silicate is the SiO2 / Na2O molar ratio specified in JIS K 1408:1966.

[0075] In the coating composition experiments, the coating compositions of Examples 1 to 5 and Comparative Examples 1 and 2 were produced by mixing the components listed in the "Composition of Coating Composition" row in Table 1 with water. The blending amounts of the components listed in the "Composition of Coating Composition" row are in parts by mass, and the components listed in the "Composition of Coating Composition" row are non-volatile components. In each of the Examples and Comparative Examples, the mass ratio of the total non-volatile components to the total mass of the coating composition was 60 mass%, and the mass ratio of water was 40 mass%.

[0076] Furthermore, the decorative paints of Examples 1 to 5 and Comparative Examples 1 and 2 were produced by mixing the components listed in the "Composition of decorative paint" in Table 1 with water. The units of blending amounts of components listed in the "Composition of decorative paint" row are parts by mass. The components listed in the "Composition of decorative paint" row are non-volatile components. In each Example and Comparative Example, the mass ratio of the total non-volatile components to the total mass of the decorative paint was 35 mass%, the mass ratio of water was 65 mass%, and the application amount of the decorative paint (non-volatile components) was 30 g / m2.

[0077] In the sheet-form molding experiments, the components listed in the "Composition of sheet-form molding" row in Table 2 were kneaded, molded using an extruder, and dried to produce sheet-form moldings in Examples 6 to 12 and Comparative Examples 3 and 4. The blending amounts of the components listed in the "Composition of sheet-form molding" row are in parts by mass, and the components listed in the "Composition of sheet-form molding" row are non-volatile contents. In each example and comparative example, the moisture content of the sheet-form molding was 5% by mass.

[0078] Separators of Examples 6 to 12 and Comparative Examples 3 and 4 were produced by kneading the components listed in the "Composition of synthetic resin film" row in Table 2 and molding them to a thickness of 38 μm. The blending amounts of the components listed in the "Composition of synthetic resin film" row are in parts by mass. All of these synthetic resin films are transparent.

[0079] In Table 2, the position of the synthetic resin film is referred to as the "top surface" when it is installed on the side that will be heated in the event of a fire, as the "wood surface" when it is installed on the side that comes into contact with the wood, and as "both surfaces" when it is installed on both sides.

[0080] Each example and each comparative example was evaluated as follows. To test the stability of the coating composition, the resulting coating composition was sealed in a 100 ml plastic container and left in a thermostatic chamber at 50°C for 28 days to check whether the coating composition had solidified. "Good" means no change from the state before leaving it at 50°C, "Good" means that the composition was slightly thickened but still had fluidity, and "Poor" means that the composition had no fluidity.

[0081] The size of the substrate for each test specimen was 99 mm in length, 99 mm in width, and 30 mm in thickness. The coating composition was applied to the surface of the substrate, or the sheet-shaped molded product (together with the transparent resin layer for test specimens with a transparent resin layer) was fastened with construction staples, and then the test specimen was prepared by leaving it to stand at 23°C and 50% RH for 14 days.

[0082] To test the flexibility of the coating film, a test specimen coated with the coating composition was left to stand in a thermostatic chamber at 23°C and 50% RH for 16 hours, then left to stand in a thermostatic chamber at -20°C (without humidity control) for 4 hours, and then left to stand in a thermostatic chamber at 50°C (without humidity control) for another 4 hours. This cycle was repeated 10 times, and the appearance of the coating film was visually inspected for defects such as cracks. "〇" means no abnormalities, "△" means that there were cracks visible even when observed from a distance of 30 cm or more from the surface of the test specimen, and "×" means that there were cracks visible even when observed from a distance of 2 m or more from the surface of the test specimen.

[0083] The sheet moldability test was performed by visually observing the degree of spread when 100 g of the sheet intermediate was dropped onto the center of a circular EVA film with a diameter of 100 mm. "◯" means that the sheet hardly spread, "△" means that the sheet spread but did not protrude from the EVA film, and "×" means that the sheet protruded from the EVA film.

[0084] The flexibility of the sheet was evaluated by determining whether cracks occurred in the sheet-shaped molding when it was attached to the substrate with construction staples (and the transparent resin layer). "Good" means no abnormalities, "Good" means that there were visible cracks even when observed from a distance of 30 cm or more from the surface of the test specimen, and "Poor" means that there were visible cracks even when observed from a distance of 2 m or more from the surface of the test specimen.

[0085] Using the cone calorimeter method specified in ISO5660-1, the total heat generation and maximum heat generation rate were measured when the test specimen was heated for 10 minutes at a radiation intensity of 50 kW / m2. The measurement results for total heat generation are shown in the "Total Heat Generation" row in Tables 1 and 2. "◎" means that the total heat generation was less than 2 MJ / m2. "〇" means that the total heat generation was less than 5 MJ / m2. "△" means that the total heat generation was between 5 MJ / m2 and 8 MJ / m2. "×" means that the total heat generation was greater than 8 MJ / m2.

[0086] The measurement results of the maximum heat release rate are shown in the "Maximum heat release rate" row in Tables 1 and 2. "Good" means that the time over which 200 kW / m2 was exceeded was less than 8 seconds. "Good" means that the time over which 200 kW / m2 was exceeded was 8 to 10 seconds. "Poor" means that the time over which 200 kW / m2 was exceeded was more than 10 seconds.

[0087] In each example, the total calorific value was small, whereas in comparative examples 1 to 4, the total calorific value was large.

[0088] [Table 1]

[0089] [Table 2]

[0090] Note that JIS K 1408:1966 referenced in this specification has been abolished as of the time of this application (date of abolition: January 20, 2022), but its contents can be viewed on the website of the Japanese Industrial Standards Committee (search for abolished standards).

[0091] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms. [Explanation of symbols]

[0092] 1...wood, 2...coating film or sheet-like molding, 3...transparent resin layer

Claims

1. A transparent sheet-like molding that makes wood flame retardant, The sheet-like molding contains sodium silicate, The sodium silicate has a SiO2 / Na2O molar ratio of 2.0 to 2.6 as defined in JIS K 1408:1966, A sheet-like molded product characterized in that the moisture content of the single layer made of sodium silicate is 1 to 10 mass %.

2. A sheet-like molded product as described in claim 1, characterized in that a synthetic resin film is provided on both sides of a single layer composed of sodium silicate.

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