Flame retardant laminate

Abstract

To provide a flame retardant laminate capable of exhibiting excellent flame retardancy and having excellent productivity.SOLUTION: There is provided a flame retardant laminate which comprises a combustible base material, a base material (A) having a thermal shrinkage at 250°C of 5.0% or less and an infrared reflection film in this order, wherein a laminate (X) of the base material (A) and the infrared reflection film has an average reflectance of 80% or more for light in the wavelength range of 1000 to 2500 nm and the combustible base material is at least one selected from the group consisting of paper and a resin material.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a flame retardant laminate. [Background technology]

[0002] 2. Description of the Related Art Flammable substrates such as paper and cardboard used in building interior materials and the like have a tendency to burn easily, and therefore attempts have been made to make them flame retardant. A method of using an infrared reflective layer is known as a method for achieving flame retardancy. Patent Document 1 describes an invention relating to a flame-retardant laminate, characterized in that an infrared reflective layer having an average reflectance of 20% or more for infrared rays from 800 to 1300 nm is laminated on a resin substrate. In the examples, methods for laminating the infrared reflective layer are disclosed, such as a method of applying a silver nanowire dispersion liquid, drying the coating to prepare a reflective film, and then hot pressing the resin substrate, and a method of depositing silver on a resin substrate cut to a predetermined size. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6308469 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the flame retardant laminate disclosed in Patent Document 1 may have insufficient flame retardancy, although it is shown that the ignition time of the flame retardant laminate conforming to the cone calorimeter method is extended to a certain extent. Furthermore, when the infrared reflective layer is laminated by hot pressing or vapor deposition, the lamination process becomes complicated, and it is difficult to laminate on a resin substrate having a certain size or larger, which results in poor productivity.

[0005] Therefore, an object of the present invention is to provide a flame-retardant laminate that is capable of exhibiting excellent flame retardancy and also has excellent productivity. [Means for solving the problem]

[0006] As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by a flame-retardant laminate comprising, in this order, a specific type of flammable substrate, a substrate (A) having a thermal shrinkage rate at 250°C of a certain level or less, and an infrared reflective film, wherein the laminate of the substrate (A) and the infrared reflective film (hereinafter also referred to as "laminate (X)") has an average reflectance in a specific wavelength region of a certain level or more. That is, the present invention provides the following [1] to [7].

[0007] [1] A flame-retardant laminate comprising, in this order, a flammable substrate, a substrate (A) having a heat shrinkage rate of 5.0% or less at 250°C, and an infrared reflective film, wherein the average reflectance of light in the wavelength region of 1000 to 2500 nm of a laminate (X) of the substrate (A) and the infrared reflective film is 80% or more, and the flammable substrate is at least one material selected from the group consisting of paper and resin materials. [2] The flame-retardant laminate according to [1], wherein the substrate (A) is glass or a resin film. [3] The flame-retardant laminate according to [2], wherein the resin film is made of an engineering plastic. [4] The flame-retardant laminate according to any one of [1] to [3], wherein the infrared reflective film has a multilayer structure. [5] The flame-retardant laminate according to any one of [1] to [4], wherein the infrared reflective film comprises a metal layer and an optical adjustment layer. [6] The flame-retardant laminate according to any one of [1] to [5], further comprising a protective film on a surface of the infrared reflective film. [7] The flame-retardant laminate according to any one of [1] to [6], which has a pressure-sensitive adhesive layer on a surface of the substrate (A). Effect of the Invention

[0008] According to the present invention, it is possible to provide a flame-retardant laminate which is capable of exhibiting excellent flame retardancy and is also excellent in productivity. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a schematic diagram of one embodiment of a flame-retardant laminate of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view illustrating a flame-retardant laminate according to another embodiment of the present invention. [Diagram 3] FIG. 2 is a cross-sectional view illustrating a flame-retardant laminate according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Flame-retardant laminate] The flame-retardant laminate of the present invention comprises, in this order, a flammable substrate, a substrate (A) having a heat shrinkage rate of 5.0% or less at 250°C, and an infrared reflective film, and the laminate (X) of the substrate (A) and the infrared reflective film has an average reflectance of 80% or more for light in the wavelength region of 1000 to 2500 nm. The flame-retardant laminate of the present invention has the above-mentioned structure, and therefore is capable of exhibiting excellent flame retardancy and is also excellent in productivity.

[0011] The flame-retardant laminate of the present invention will be described in detail below. FIG. 1 shows one embodiment of the flame-retardant laminate of the present invention. The flame-retardant laminate of the present invention is not limited to the drawing. As shown in FIG. 1, the flame-retardant laminate 10 of the present invention is a laminate including a combustible substrate 13, a substrate (A) 12, and an infrared reflective film 11 in this order.

[0012] <Base material (A)> The substrate (A) has a heat shrinkage rate of 5.0% or less at 250° C. If the heat shrinkage rate at 250° C. exceeds 5.0%, the flame-retardant laminate is likely to deform or crack under high temperatures such as during a fire. Therefore, the flame-retardant laminate is unlikely to exhibit excellent flame retardancy, and the flammable substrate is likely to ignite. From the viewpoint of improving flame retardancy, the heat shrinkage rate of the base material (A) at 250° C. is preferably 3.0% or less, more preferably 2.0% or less, and further preferably 1.5% or less. The lower limit of the heat shrinkage rate of the base material (A) at 250° C. is not particularly limited, and may be 0% or more. The heat shrinkage rate can be adjusted to a desired range by appropriately selecting the type of the base material (A). The heat shrinkage rate can be measured by the method described in the examples.

[0013] In the flame-retardant laminate of the present invention, by providing a substrate (A) on which an infrared reflective film is laminated, separate from the flammable substrate, it becomes possible to form the infrared reflective film with high productivity. For example, as described below, it becomes possible to form the infrared reflective film while transporting the substrate (A) by a roll-to-roll method. The substrate (A) is preferably a transparent substrate. By using the substrate (A) as a transparent substrate, it is easy to adjust the average transmittance of the laminate (X) in the wavelength region of 400 to 800 nm to a certain level or more, so that the visibility of the surface of the combustible substrate is not hindered and the design of the combustible substrate is easily maintained. The average transmittance of the transparent substrate for light in the wavelength region of 400 to 800 nm is not particularly limited, but is preferably 40% or more, and more preferably 50% or more.

[0014] The substrate (A) is not particularly limited as long as the thermal shrinkage at 250° C. is within the above-mentioned range, but is preferably glass or a resin film, and from the viewpoint of handleability, a resin film or a thin glass film is more preferable. The resin film is not particularly limited as long as it is a material that can set the heat shrinkage rate at 250°C within the above range, but is preferably made of engineering plastic. Examples of the engineering plastic are preferably polyetheretherketone (PEEK), polyimide (PI), polyparaphenylene terephthalamide (PPTA), polyetherimide (PEI), and thermoplastic polyimide (TPI). The resin film may be made of a single material or a plurality of materials.

[0015] The thickness of the substrate (A) is not particularly limited, but is, for example, 5 μm to 200 μm, preferably 5 μm to 100 μm, more preferably 10 μm to 70 μm, and even more preferably 20 μm to 50 μm. By making the thickness of the substrate (A) equal to or greater than the above lower limit, the flame retardancy of the flame-retardant laminate is easily improved. In addition, by making the thickness of the substrate (A) equal to or less than the above upper limit, for example, it becomes possible to form an infrared reflective film while transporting the substrate (A) by a roll-to-roll method, and the productivity of the flame-retardant laminate can be improved.

[0016] <Infrared reflective film> The flame-retardant laminate of the present invention includes an infrared reflective film provided on one surface of the above-mentioned substrate (A). The infrared reflective film improves the flame retardancy of the combustible substrate by reflecting radiant heat during combustion, thereby preventing the combustible substrate from igniting. The infrared reflective film may be any film that has the function of reflecting infrared rays, and may include, for example, either a metal layer or an optical adjustment layer, or both.

[0017] The infrared reflective film may have a single-layer structure or a multilayer structure, but is preferably a multilayer structure from the viewpoint of easily increasing the average transmittance of light in the wavelength region of 400 to 800 nm of the laminate (X). The multi-layered infrared reflective film preferably includes a metal layer and an optical adjustment layer, and more preferably includes metal layers and optical adjustment layers stacked alternately. The number of layers in the multilayer structure is not particularly limited, but is, for example, from 2 to 10 layers, preferably from 2 to 4 layers, and more preferably 3 layers. It is particularly preferable that the infrared reflective film has a three-layer structure in which an optical adjustment layer, a metal layer, and an optical adjustment layer are laminated in this order.

[0018] Examples of materials for the metal layer include aluminum, copper, silver, gold, palladium, titanium, iron, nickel, zinc, zirconium, chromium, molybdenum, tantalum, tungsten, indium, tin, and alloys containing these. Of these, silver, aluminum, titanium, copper, gold, and iron are preferred, and silver is particularly preferred. The thickness of the metal layer is not particularly limited, but is, for example, from 1 nm to 500 nm, preferably from 5 nm to 100 nm, and more preferably from 10 nm to 50 nm.

[0019] Examples of the optical adjustment layer include metal oxides, such as titanium dioxide (TiO2), titanium oxide (TiO), zinc oxide (ZnO), zinc sulfide (ZnS), niobium oxide (Nb2O5), cerium oxide (CeO2), tantalum oxide (Ta2O5), aluminum oxide (Al2O3), zirconium oxide (ZrO2), silicon dioxide (SiO2), tin dioxide (SnO2), tin-doped indium oxide (ITO), cerium-doped indium oxide (ICO), gallium-doped zinc oxide (GZO), aluminum-doped zinc oxide (AZO), indium oxide-zinc oxide (IZO), and antimony-doped tin oxide (ATO). Among these, aluminum-doped zinc oxide (AZO) is preferred. The thickness of the optical adjustment layer is not particularly limited, but is, for example, from 1 nm to 500 nm, preferably from 5 nm to 100 nm, and more preferably from 10 nm to 50 nm.

[0020] The infrared reflective film may also be made of a metal layer alone. The thickness of the infrared reflective film is not particularly limited, but is, for example, 5 nm to 1000 nm, preferably 10 nm to 200 nm, and more preferably 30 nm to 100 nm. By making the thickness of the infrared reflective film equal to or greater than the lower limit, the flame retardancy is easily improved, and by making the thickness of the infrared reflective film equal to or less than the upper limit, the transparency is easily improved.

[0021] The method for laminating the infrared reflective film on the substrate (A) is preferably a sputtering method, from the viewpoint of improving the productivity of the flame-retardant laminate. When the sputtering method is used, a known sputtering device may be used. From the viewpoint of productivity, the infrared reflective film is preferably laminated on the substrate (A) transported by a roll-to-roll method, and more preferably, the infrared reflective film is formed by sputtering on the substrate (A) transported by a roll-to-roll method.

[0022] <Flammable base material> The combustible substrate is at least one selected from the group consisting of paper and resin materials. In the flame-retardant laminate, the combustible substrate is provided on the surface of the substrate (A) opposite to the surface on which the infrared reflective film is provided. The paper may be any known paper such as white cardboard, craft paper, Japanese paper, liner paper, coated paper, miscellaneous paper, etc. Cardboard may also be used as the paper. The resin used for the resin material is not particularly limited, and may be a thermoplastic resin or a curable resin such as a thermosetting resin or a photocurable resin. Examples of the resin include a polycarbonate resin, a polyolefin resin, a polyester resin such as polyethylene terephthalate, an acrylic resin, a urethane resin, a styrene resin, an ABS resin, a polyamide resin, a polyvinyl chloride resin, a polyvinyl alcohol resin, a polyvinyl acetal resin, a phenolic resin, a thermoplastic elastomer, an elastomer resin such as various rubber components, an epoxy resin, a melamine resin, and the like. The resin material may be a resin alone or may be a resin to which a known additive is added. The resin material may be a non-foamed material or a foamed material (resin-based foamed material). The resin used for the resin-based foam may be appropriately selected from the above-mentioned resins, but preferred examples include polyolefin-based resins, urethane-based resins, acrylic-based resins, elastomer-based resins, phenol-based resins, styrene-based resins, and polyester-based resins. The combustible base material may be one of the above materials, or two or more of them may be used in combination. The combustible material may be a composite of paper and a resin material.

[0023] A flammable base material is a material that easily burns when it is a single flammable base material. There is no particular limitation on the flammable base material. For example, a flammable base material alone is a material that easily burns when it is a single flammable base material. In a heat generation test using a cone calorimeter tester described later, the flammable base material alone is a material that easily burns when it is a single flammable base material. 2 When heated at 100°C, the total heat generated is relatively large. For example, the total heat generated after 5 minutes is 8 MJ / m 2 May be greater than 20MJ / m 2 In addition, in a heat generation test using a cone calorimeter tester, the ignition time may be, for example, less than 100 seconds, or may be less than 30 seconds.

[0024] The thickness of the combustible base material is not particularly limited, but is, for example, 0.5 mm or more and 50 mm or less, preferably 1 mm or more and 20 mm or less, and more preferably 1.5 mm or more and 5 mm or less.

[0025] The flame-retardant laminate of the present invention can be obtained, for example, by laminating the above-mentioned laminate (X) on a flammable substrate. The method of laminating the laminate (X) on the flammable substrate is not particularly limited, and for example, the flammable substrate and the laminate (X) may be laminated by thermocompression bonding or the like, or, as described later, the substrate (A) constituting the laminate (X) and the flammable substrate may be bonded with an adhesive.

[0026] The flame-retardant laminate of the present invention may comprise only the above-mentioned combustible substrate, substrate (A), and infrared reflective film, or may comprise layers other than these. For example, as shown in FIG. 2, the flame-retardant laminate 10 may comprise a protective film 14 on the surface of the infrared reflective film 11. By providing the flame-retardant laminate with a protective film, the infrared reflective film can be appropriately protected, for example, by improving the scratch resistance of the infrared reflective film. In addition, the protective film may be embossed on the surface. The protective film may be a resin film, or an inorganic film such as diamond-like carbon (DLC), alumina, or silicon dioxide. The thickness of the protective film is not particularly limited, but is, for example, from 0.1 μm to 10 μm, and preferably from 0.5 μm to 5 μm.

[0027] As shown in FIG. 3, the flame-retardant laminate 10 of the present invention may have a pressure-sensitive adhesive layer 15 on the surface of a substrate (A) 12, and a flammable substrate 13 may be attached to the substrate (A) 12 via the pressure-sensitive adhesive layer 15. The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive. The pressure-sensitive adhesive is not particularly limited, and examples thereof include acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, polyolefin pressure-sensitive adhesives, polyester pressure-sensitive adhesives, vinyl alkyl ether pressure-sensitive adhesives, polyamide pressure-sensitive adhesives, rubber pressure-sensitive adhesives, silicone pressure-sensitive adhesives, and fluorine pressure-sensitive adhesives. The adhesive layer may be a double-sided tape (double-sided adhesive tape) having adhesives on both sides of a substrate. The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is, for example, from 10 μm to 150 μm, and preferably from 30 μm to 100 μm.

[0028] The flame-retardant laminate of the present invention may include both the protective film and the pressure-sensitive adhesive layer described above, or may include layers other than the protective film and the pressure-sensitive adhesive layer as long as the effects of the present invention are not impaired.

[0029] <Average reflectance> In the present invention, the average reflectance of the laminate (X) to light in the wavelength region of 1000 to 2500 nm is 80% or more. The flame-retardant laminate of the present invention has a structure in which the laminate (X) with high reflectance is laminated on a flammable substrate, and thus the flame-retardant laminate as a whole has excellent flame retardancy despite having a flammable substrate. On the other hand, if the average reflectance of the laminate (X) is less than 80%, it becomes difficult to reflect radiant heat during combustion, and the flame retardancy of the flame-retardant laminate decreases. The average reflectance of the laminate (X) for light in the wavelength region of 1000 to 2500 nm is preferably 85% or more. The upper limit of the average reflectance is 100%. As described above, the laminate (X) is a laminate of the substrate (A) and the infrared reflective film. However, in the case where the flame-retardant laminate has a layer other than these between the substrate (A) and the infrared reflective film, the laminate (X) also includes that layer. The average reflectance can be adjusted by the type, thickness, etc. of the infrared reflective film. The average reflectance is measured by a spectrophotometer from the surface of the laminate (X) on the infrared reflective film side. The details of the measurement are as described in the Examples.

[0030] <Average transmittance> The average transmittance of the laminate (X) of the present invention for light in the wavelength region of 400 to 800 nm is not particularly limited, but is preferably 40% or more. If the average transmittance is 40% or more, the combustible substrate can be visually recognized from the laminate (X) side, and the design of the flame-retardant laminate is likely to be improved. From the same viewpoint, the average transmittance of the laminate (X) for light in the wavelength region of 400 to 800 nm is preferably 45% or more, more preferably 50% or more, and even more preferably 55% or more. The upper limit of the average transmittance is 100%. The average transmittance can be adjusted by the type and thickness of the substrate (A) and the infrared reflective film. The average transmittance is measured by a spectrophotometer. The details of the measurement are as described in the Examples.

[0031] The flame-retardant laminate of the present invention has a radiant heat intensity of 50 kW / m in a heat generation test using a cone calorimeter tester in accordance with ISO 5660-1. 2 When heated at 40°C, the total heat generated after 5 minutes is 8MJ / m 2 It is preferable that the total heat generation amount after 10 minutes is 8MJ / m or less. 2 It is more preferable that the total heat generation amount after 20 minutes is 8 MJ / m or less. 2It is even more preferable that: From the viewpoint of flame retardancy, the flame-retardant laminate of the present invention preferably has an ignition time of 400 seconds or more, more preferably 600 seconds or more, and even more preferably does not ignite when heated as described above. The ignition time can be obtained by the method described in the Examples. EXAMPLES

[0032] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these.

[0033] The various measurement methods are as follows. [Average reflectance] The average reflectance of light in the wavelength region of 1000 to 2500 nm was measured for the laminates (X) produced in each of the Examples and Comparative Examples using a spectrophotometer ("V-670" manufactured by JASCO Corporation). The measurements were performed at room temperature (25°C). The average reflectance was measured for the surface of the laminate (X) on the infrared reflective film side.

[0034] [Average transmittance] The average transmittance of light in the wavelength region of 400 to 800 nm was measured for the laminates (X) produced in each of the Examples and Comparative Examples using a spectrophotometer ("V-670" manufactured by JASCO Corporation). The measurement was carried out at room temperature (25°C).

[0035] [Heat shrinkage rate] The thermal shrinkage of the transparent substrate used in each of the Examples and Comparative Examples was measured as follows. The thermal shrinkage refers to the ratio of dimensions before and after heat treatment of a transparent substrate (rectangular shape with a length of 50 mm and a width of 50 mm) at 250°C for 5 minutes and then returned to room temperature (25°C), and can be calculated by the following formula. The thermal shrinkage was measured in both the vertical and horizontal directions of the transparent substrate, and the average value was calculated. That is, the thermal shrinkage of the vertical and horizontal dimensions was calculated by the following formula, and the thermal shrinkage in the present invention was calculated by averaging these values. Heat shrinkage rate (%) = 100 x (dimension before heating - dimension after heating) / dimension before heating

[0036] [Cone calorimeter test] The flame-retardant laminates produced in each of the Examples and Comparative Examples were subjected to a cone calorimeter test in accordance with ISO5660-1 with the infrared reflective film facing up, with a radiant heat intensity of 50 kW / m 2 The test was carried out to confirm whether the material had flame retardant, semi-nonflammable, or nonflammable properties. Flame retardant performance is equivalent to a radiation heat intensity of 50kW / m in a heat generation test using a cone calorimeter tester in accordance with ISO5660-1. 2 When heated at 40°C, the total heat generated after 5 minutes is 8MJ / m 2 In addition, the performance equivalent to quasi-noncombustible is a total heat release of 8MJ / m after 10 minutes. 2 In addition, non-combustible performance is when the total heat generated after 20 minutes is 8MJ / m 2 The result is as follows. In addition, the radiant heat intensity is 50kW / m 2 The time from the start of the test until the flame-retardant laminate ignited when heated at 40° C. was measured and recorded as the ignition time (seconds). If the laminate did not ignite within 20 minutes after the start of the test, the result was recorded as "no ignition."

[0037] <Example 1> A 25 μm thick polyimide (PI) film (IST Corporation's "TORMED Type C") was prepared as a transparent substrate (substrate (A)). While the polyimide film was transported by a roll-to-roll method, aluminum-doped zinc oxide (AZO), silver (Ag), and aluminum-doped zinc oxide (AZO) were laminated in this order on one surface of the polyimide film using a sputtering device (ULVAC Kyushu Corporation's "QAM-4") to form an infrared reflective film, thereby producing a laminate (X). The thickness of each layer of AZO and Ag was calculated from the adhesion amount and specific gravity by fluorescent X-ray analysis, and is shown in Table 1. The transparent substrate side of the laminate (X) was attached to a flammable substrate made of a polycarbonate (PC) plate (Takiron C.I.'s "Polycarbonate Plate", thickness 2 mm) using double-sided tape (Sekisui Chemical Co., Ltd.'s "Double Tack Tape No. 570E", thickness 120 μm) to produce a flame-retardant laminate. The thickness of the infrared reflective film from the transparent substrate side was AZO 18 nm, Ag 23 nm, and AZO 27 nm. The various evaluation results are shown in Table 1.

[0038] <Examples 2 to 4, Comparative Example 1> A flame-retardant laminate was produced in the same manner as in Example 1, except that the types of the transparent substrate and the combustible substrate, and the thicknesses of the layers constituting the infrared reflective film were as shown in Table 1. In the table, "PEEK" stands for polyether ether ketone, and "PEN" stands for polyethylene naphthalate. The PEEK used was "EXPEEK" manufactured by Kurabo Industries, the glass used was "G-Leaf" manufactured by Nippon Electric Glass Co., Ltd., and the PEN used was "Teonex Q51" manufactured by Toyobo Co., Ltd. The paper used as the flammable substrate was "white cardboard" manufactured by Nippon Himobuton Trading Co., Ltd.

[0039] [Table 1]

[0040] As shown in the above examples, the flame-retardant laminates of each example, which have a transparent substrate with a thermal shrinkage rate of 5.0% or less at 250°C, an infrared reflective film, and the laminate (X) has a certain or higher average reflectance at 1000 to 2500 nm and an average transmittance at 400 to 800 nm, were found to have excellent flame retardancy when equipped with a flammable substrate. Furthermore, in each example, the flame-retardant laminate was produced using a roll-to-roll method in the transport process of the substrate (A), and therefore the productivity was also excellent. In contrast, it was found that the flame-retardant laminate of Comparative Example 1, which used a transparent substrate having a thermal shrinkage rate of more than 5.0% at 250° C., had poor flame retardancy. [Explanation of symbols]

[0041] 10. Flame-retardant laminate 11 Infrared reflective film 12 Base material (A) 13 Flammable substrates 14 Protective film 15 Adhesive layer

Claims

1. A flammable substrate, a substrate (A) having a thermal shrinkage rate of 5.0% or less at 250°C, and an infrared reflective film in this order; The laminate (X) of the substrate (A) and the infrared reflective film has an average reflectance of 80% or more for light in the wavelength region of 1000 to 2500 nm; The flame-retardant laminate, wherein the flammable substrate is at least one selected from the group consisting of paper and resin materials.

2. The flame-retardant laminate according to claim 1 , wherein the substrate (A) is glass or a resin film.

3. The flame-retardant laminate according to claim 2 , wherein the resin film is made of an engineering plastic.

4. The flame-retardant laminate according to claim 1 or 2, wherein the infrared reflective film has a multi-layer structure.

5. The flame-retardant laminate according to claim 1 or 2, wherein the infrared reflective film comprises a metal layer and an optical adjustment layer.

6. The flame-retardant laminate according to claim 1 , further comprising a protective film on a surface of the infrared reflective film.

7. The flame-retardant laminate according to claim 1 or 2, which has a pressure-sensitive adhesive layer on a surface of the substrate (A).

Images