Thermal insulation laminate

Abstract

To realize a thermal insulation laminate with excellent cushioning, heat insulation, and flame resistance. [Solution] The thermal insulation laminate 100 comprises a flame-retardant layer 101, a buffer layer 102, and an intermediate layer 103 provided between the flame-retardant layer 101 and the buffer layer 102, with the entire surface of the intermediate layer 103 in close contact with the flame-retardant layer 101 and the buffer layer 102. When a 1300°C flame is brought into contact with the exposed surface of the flame-retardant layer 101 or the buffer layer 102 for 5 minutes, the surface temperature of the surface opposite to the surface that was in contact with the flame is less than 350°C, and the flame retardancy when tested in accordance with the US UL94 standard is V-0.

Description

[Technical Field]

[0001] This disclosure relates to thermal insulation laminates. [Background technology]

[0002] Rechargeable batteries such as lithium-ion batteries are becoming increasingly important as power sources for electric vehicles and other electric vehicles. They are also expected to be used as energy storage equipment to efficiently utilize electricity generated by solar cells and other sources.

[0003] To achieve high-capacity power, multiple battery cells are integrated to form a battery unit. As the electrical capacity of a battery increases, it becomes more susceptible to thermal runaway, and the heat generated tends to reach high temperatures. For example, if one battery cell experiences thermal runaway due to an internal short circuit, overcharging, use in a high-temperature environment, or a vehicle accident, the heat generated can propagate to adjacent cells, potentially causing the entire battery unit to catch fire.

[0004] As a means of reducing the propagation of such thermal runaway, insulating materials placed between battery cells are attracting attention. While high heat shielding properties are naturally required of insulating materials, battery cells also expand and contract due to charging and discharging, heat, and external shocks. Therefore, insulating materials placed between battery cells must also have buffering properties to absorb the expansion and contraction of the battery cells and external shocks.

[0005] To satisfy both heat shielding and cushioning properties, laminated sheets have been proposed, for example, in which a heat insulating sheet made of a fiber sheet and silica aerogel is laminated with a rubber-like elastic sheet (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2020 / 194939 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, if thermal runaway occurs in a battery cell, a flame with a high temperature of around 1000°C and high injection pressure is generated from the battery cell. Conventional insulation materials have not been designed to withstand such high-temperature conditions, making it difficult to adequately prevent the propagation of thermal runaway. If the thickness of the insulation sheet is increased to prevent the propagation of thermal runaway, the overall thickness of the insulation material also increases, and the volume and weight of the entire battery unit also increase. If the battery unit becomes large and heavy, for example in the case of automotive applications, the number of battery cells that can be installed decreases, making it difficult to achieve a sufficient driving range. In order to increase the thickness of the insulation sheet while keeping the overall thickness of the insulation material down, the elastic sheet is made thinner or removed completely, which reduces the cushioning effect, making it difficult to achieve both cushioning and sufficient thermal insulation and flame protection.

[0008] These problems with conventional insulation materials are not limited to insulation materials placed between battery cells; they can also occur with insulation materials used in other applications.

[0009] The objective of this disclosure is to realize a thermal insulation laminate that has sufficient thermal insulation and flame-retardant properties while ensuring buffering capabilities. [Means for solving the problem]

[0010] A first aspect of the thermal insulation laminate of the present disclosure comprises a flame-resistant layer, a buffer layer, and an intermediate layer provided between the flame-resistant layer and the buffer layer and in close contact with the flame-resistant layer and the buffer layer, wherein when a flame of 1300°C is brought into contact with an exposed surface of the flame-resistant layer or the buffer layer for 5 minutes, the surface temperature of the surface opposite to the surface that was brought into contact with the flame is less than 350°C, and the flame retardancy when tested in accordance with the US UL94 standard is V-0.

[0011] In the first aspect of the heat-insulating laminate, when it is brought into contact with a 1300°C flame for 5 minutes, the surface temperature of the surface opposite to the surface in contact with the flame is less than 350°C, and it is possible to make it difficult for the heat generated by a battery cell or the like to affect other members. Further, due to the buffer layer, it is possible to make it difficult to be affected by deformation of the contacting member or the like. Furthermore, sufficient flame retardancy can be ensured.

[0012] In one aspect of the heat-insulating laminate, the intermediate layer can be a resin layer containing an acrylic elastomer. By adopting such a configuration, when the temperature becomes high, at least a part of the intermediate layer disappears, and it becomes easy to form a layer of air with high heat insulation between the flame shielding layer and the buffer layer, so that excellent heat insulation can be realized.

[0013] In one aspect of the heat-insulating laminate, the intermediate layer and / or the buffer layer can contain at least one flame retardant selected from a phosphorus-based flame retardant and an intumescent flame retardant. By adopting such a configuration, it is possible to make the heat-insulating laminate less likely to catch fire, so that safety is improved.

[0014] In each aspect of the heat-insulating laminate, the flame shielding layer can be a layer containing at least one selected from inorganic particles, inorganic fibers, and inorganic porous bodies. By adopting such a configuration, excellent flame shielding properties can be realized.

[0015] In each aspect of the heat-insulating laminate, the buffer layer can be a layer formed of a porous resin. By adopting such a configuration, excellent buffering properties can be realized.

[0016] In each aspect of the heat-insulating laminate, the breakdown voltage can be 1.5 kV / mm or more. By adopting such a configuration, it can be used for applications where electrical insulation is required.

[0017] In each aspect of the heat-insulating laminate, the 25% compression stress can be 0.1 MPa or less, and the 50% compression permanent strain can be 1% or less. By adopting such a configuration, it is possible to make it difficult for the effects of deformation and expansion to affect other members.

[0018] In each aspect of the heat-insulating laminate, the density can be 0.1 g / cm 3 or more and 1 g / cm 3 or less. By adopting such a configuration, the overall weight can be reduced.

[0019] One aspect of the battery unit of the present disclosure includes a heat-insulating laminate in each aspect and a plurality of battery cells, and the heat-insulating laminate is at least disposed between the plurality of battery cells. By adopting such a configuration, a battery unit with high safety can be realized.

[0020] One aspect of the method for manufacturing the heat-insulating laminate of the present disclosure is to prepare a flame-retardant layer forming sheet, a buffer layer forming sheet, and an intermediate layer forming sheet, and dispose the intermediate layer forming sheet between the flame-retardant layer forming sheet and the buffer layer forming sheet and perform roll lamination or laminated pressing. By adopting such a configuration, the heat-insulating laminate can be easily manufactured.

Advantages of the Invention

[0021] According to the heat-insulating laminate of the present disclosure, cushioning properties, sufficient heat insulation properties, and flame shielding properties can be realized.

Brief Description of the Drawings

[0022] [Figure 1] It is a cross-sectional view showing a heat-insulating laminate according to an embodiment. [Figure 2] It is a cross-sectional view showing a battery unit using a heat-insulating laminate according to an embodiment. [Figure 3] It is a cross-sectional view showing a modified example of the heat-insulating laminate. [Figure 4] It is a cross-sectional view showing a modified example of the heat-insulating laminate. [Figure 5] It is a graph showing an example of measurement of heat insulation property. [Figure 6] It is a graph showing an example of measuring the heat insulation property by changing the temperature of the flame.

Modes for Carrying Out the Invention

[0023] As shown in Figure 1, the thermal insulation laminate 100 of this disclosure has a flame-shielding layer 101, a buffer layer 102, and an intermediate layer 103. The thermal insulation laminate 100 of this embodiment can be placed, for example, between the battery cells 201 that serve as heat sources, or between the battery cells 201 and the housing 202, as shown in Figure 2. It is not necessary for the battery cells 201 and the thermal insulation laminate 100 to be in contact, but from the viewpoint of making the battery unit compact, it is preferable for the battery cells 201 and the thermal insulation laminate 100 to be in contact.

[0024] The thermal insulation laminate 100 of this embodiment can prevent heat from being transferred to other battery cells 201 in the event that one battery cell 201 experiences thermal runaway. Furthermore, because it has buffering properties, even when placed in contact with the battery cells 201, it can absorb volume changes and deformations of the battery cells 201, making it difficult for stress to be transferred to other battery cells 201.

[0025] In this embodiment, the thermal insulation laminate 100 preferably expands moderately when exposed to high temperatures in order to ensure sufficient thermal insulation. This forms an air-insulating layer containing air between the thermal insulation laminates 100, thereby achieving excellent thermal insulation. From the viewpoint of facilitating the formation of the air-insulating layer, the expansion rate of the thermal insulation laminate 100 when the flame-shielding layer 101 or the buffer layer 102 is exposed to a 1300°C flame for 5 minutes is preferably 200% or more, more preferably 250% or more. From the viewpoint of suppressing stress on surrounding members, the expansion rate of the intermediate layer 103 is preferably 400% or less, more preferably 350% or less. The expansion rate of the thermal insulation laminate can be measured by the method shown in the examples.

[0026] The flame-shielding layer 101 is preferably made of a material with excellent heat resistance and flame retardancy. From the viewpoint of preventing heat from heat source components such as battery cells 201 from being easily transmitted to adjacent components, the thermal conductivity is preferably 1 W / m·K or less, and more preferably 0.3 W / m·K or less. The thermal conductivity can be measured using a steady-state thermal conductivity measuring device.

[0027] The flame-retardant layer 101 is not particularly limited, but from the viewpoint of heat resistance, it may contain at least one selected from inorganic particles, inorganic fibers, and inorganic porous materials, for example, an inorganic particle sheet, an inorganic fiber sheet, or an inorganic porous material sheet. Furthermore, these sheets can be used individually or in combination as a composite sheet. Here, it is preferable that the inorganic particles, inorganic fibers, and inorganic porous materials contain at least one selected from those with a melting point of 600°C or higher, more preferably 1000°C or higher, and the sheet containing at least one selected from inorganic particles, inorganic fibers, and inorganic porous materials preferably retains its shape before and after heating at 1000°C for 5 minutes.

[0028] An inorganic particle sheet is a sheet containing inorganic particles. The shape of the inorganic particles contained in the inorganic particle sheet is not particularly limited, but examples include spherical, flaky, plate-like, needle-like, branch-like, etc. Examples of inorganic particles that can be used include silica, glass particles, glass balloons, mica, talc, kaolin, fly ash balloons, shirasu balloons, perlite, cenospheres, lanthanum hexaboride, wollastonite, silicon nitride, silicon carbide, calcium silicate, boron nitride, aluminum nitride, aluminum hydroxide, aluminum oxide, calcium carbonate, magnesium carbonate, potassium titanate, magnesium hydroxide, aluminum borate, barium sulfate, barium titanate, hydrotalcite, dolomite, montmorillonite, bentonite, boehmite, smectite, zonolite, sepiolite, verculite, sericite, and zirconia. By using inorganic particles with high electrical insulation properties such as mica, the electrical insulation properties of the flame-shielding layer 101 can be improved. The inorganic particles may be non-hollow particles or hollow particles. However, the thermal insulation properties can be further improved by using hollow particles. In addition, the inorganic particles may be subjected to known surface treatments such as silane coupling treatment or stearic acid treatment to improve their dispersibility.

[0029] The inorganic particle sheet may contain a binder other than inorganic particles to improve handling and prevent particle shedding. The binder may be a resin such as silicone, polyolefin, polyamide, or polyimide, or an organic fiber such as cellulose fibers, polyvinyl alcohol fibers, or polyester fibers. From the viewpoint of improving flame resistance and heat resistance, the inorganic particle content is preferably 20% by volume, more preferably 50% or more by volume, and even more preferably 80% or more by volume, when the volume of the flame-retardant layer 101 is considered as 100% by volume.

[0030] Inorganic particle sheets include mica sheets and mica paper made by adding a binder to natural or synthetic mica to form a sheet, as well as mica plates made in plate form. From the viewpoint of minimizing powder shedding and ease of handling, mica sheets made by adding a binder to mica to form a sheet are more preferred. The mica may be natural mica such as muscovite, biotite, and phlogopite that occurs naturally, or synthetic mica that is artificially produced, and may be soft mica or hard mica, and calcined mica or uncalcined mica. The method for manufacturing mica sheets is not particularly limited, but can be manufactured by known methods. For example, composite mica can be impregnated with a binder such as silicone, polyolefin, polyamide, or polyimide, and optionally used with surfactants or reinforcing substrates.

[0031] Commercially available mica sheets include "D581" and "D680" from Okabe Mica Industry Co., Ltd., which integrate rigid laminated mica with silicone adhesive; "Mica-chan" from Wide Work Co., Ltd., which integrates rigid unfired laminated mica with silicone adhesive; "D581A" and "D680A" from Okabe Mica Industry Co., Ltd., which integrate flexible laminated mica with silicone adhesive; and "D461" from Okabe Mica Industry Co., Ltd., which integrates rigid unfired laminated mica with epoxy adhesive. Among these, mica sheets made by integrating rigid laminated mica with silicone adhesive are preferred, and from the viewpoint of flame resistance, it is preferable that they have excellent flame retardancy, and it is preferable to select a mica sheet that meets the V-0 grade of the US UL-94 standard.

[0032] Furthermore, the flame-retardant layer 101 is not limited to an inorganic particle sheet containing inorganic particles, but can also be a sheet containing inorganic fibers or an inorganic porous material. From the viewpoint of handling and processability, it is more preferable that the sheet contains inorganic particles or inorganic fibers.

[0033] Inorganic fiber sheets are sheets containing inorganic fibers, and can be woven fabrics, nonwoven fabrics, chopped strand mats, or paper-formed bodies made from glass fibers, silica fibers, alumina fibers, aluminum silicate fibers, titania fibers, zirconia fibers, silicon carbide fibers, metal fibers, rock wool, and basalt fibers. Heat resistance can be further improved by using silica fibers or alumina fibers. Sheets using glass fibers as the inorganic fiber are preferred from the viewpoint of low powder shedding, ease of handling, and low cost.

[0034] Examples of commercially available glass fiber sheets include Unitika Ltd.'s glass cloth "H100F120," Oji F-Tex Corporation's glass paper "Grasper (registered trademark)," Olivest Corporation's glass fiber paper "Grabest (registered trademark)," Mitsubishi Paper Mills Ltd.'s glass fiber nonwoven fabric "Barrier," and Central Glass Co., Ltd.'s chopped strand mat "ECM380-501." These glass fiber sheets exhibit excellent roll-to-roll processability. Among these, Mitsubishi Paper Mills Ltd.'s "GP100-TR," "GP100-TRO," "GP50-TR," and "GP60-TRO," which are glass fiber nonwoven fabrics with an inorganic particle layer formed on the surface, are preferred.

[0035] The method for manufacturing glass fiber nonwoven fabric is not particularly limited, but it can be manufactured by known methods. For example, glass fibers can be mixed with a moist heat adhesive binder such as cellulose fibers, polyvinyl alcohol fibers, or polyester fibers, or with heat-resistant organic fibers such as aramid fibers or their fibrillated forms, and manufactured by a wet papermaking method. An inorganic particle layer may be provided on the surface of the glass fiber nonwoven fabric to further improve its flame resistance. The inorganic particles mentioned above can be used for the inorganic particle layer, and for example, clay minerals such as kaolin, bentonite, and sepiolite can be used. From the viewpoint of flame resistance, the glass fiber nonwoven fabric is preferably highly flame-retardant, and it is preferable to select a glass fiber nonwoven fabric that meets the V-0 grade of the US UL-94 standard.

[0036] An inorganic porous sheet is a sheet containing an inorganic porous material. Examples of inorganic porous materials include porous inorganic compounds such as aerogels produced by supercritical drying, cryogels produced by freeze-drying, and xerogels produced by solvent evaporation drying. From the viewpoint of weight reduction and heat insulation, the porosity of the inorganic porous material contained in the inorganic porous sheet is preferably 90% or more, the pore size is preferably 10 nm or more and 300 nm or less, and it is preferably an aerogel.

[0037] Examples of aerogels include silica aerogel, carbon aerogel, alumina aerogel, and titania aerogel, with silica aerogel being preferred due to its availability. The method for producing silica aerogel is not particularly limited, but to improve handling, it may include a step of compounding the silica aerogel with an inorganic fiber sheet such as a glass nonwoven fabric. For example, it can be produced by a sol production step of hydrolyzing a silane oligomer to produce a sol containing the hydrolysis product of the silane oligomer, an impregnation step of impregnating a glass nonwoven fabric with the sol, a wet gel production step of gelling the sol to obtain a wet gel, and a drying step of drying the wet gel to obtain an aerogel.

[0038] The flame-retardant layer 101 may also be a layer containing organic particles, organic fibers, organic or inorganic binders, and flame retardants, in addition to inorganic particles, inorganic fibers, or inorganic porous materials. Furthermore, the flame-retardant layer 101 may be a single layer, or it may be a composite layer made up of multiple materials. In addition, the flame-retardant layer 101 may have a protective film on its surface to prevent the shedding of particles and fibers.

[0039] The flame-shielding layer 101 can be electrically insulating or conductive. When used in battery units or the like, it is preferable that it be electrically insulating, and that the dielectric breakdown voltage be 1 kV / mm or higher, and more preferably 3 kV / mm or higher. The dielectric breakdown voltage can be measured in the same manner as shown in the examples.

[0040] The thickness of the flame-retardant layer 101 is preferably 0.02 mm or more, and more preferably 0.1 mm or more, from the viewpoint of thermal insulation and flame-retardant properties. Furthermore, from the viewpoint of roll-to-roll processability and space saving when manufacturing the thermal insulation laminate 100, the thickness is preferably 2 mm or less, and more preferably 1 mm or less.

[0041] From the viewpoint of ensuring impact absorption and stress relaxation for the entire thermal insulation laminate 100, the thickness of the flame-retardant layer 101 is preferably less than 50% of the total thickness of the thermal insulation laminate 100, and more preferably less than 25%. It is also preferable that it be thinner than the buffer layer 102.

[0042] The buffer layer 102 has the function of protecting adjacent components by absorbing volume changes and deformations of surrounding components such as the battery cell 201, and by absorbing external shocks.

[0043] The buffer layer 102 is not particularly limited, but a resin sheet is preferred from the viewpoint of handling and buffering properties. For example, it can be a sheet of silicone, polyolefin, polyurethane, polyester, polystyrene, polyvinyl acetal, polyvinyl alcohol, polycarbonate, polyphenylene ether, polyvinyl chloride, ethylene vinyl acetate copolymer, polyimide, polyamide, acrylic resin, fluororesin, phenolic resin, urea resin, melamine resin, epoxy resin, nitrile rubber, chloroprene rubber, ethylene propylene rubber, butyl rubber, and natural rubber, as well as copolymers, mixtures, and composites thereof.

[0044] The buffer layer 102 is preferably a porous sheet having air bubbles inside. By being porous, it is easier to deform, and the impact absorption effect and stress relaxation effect can be further enhanced. Furthermore, being porous is also advantageous from the viewpoint of weight reduction. In the case of porous material, the internal air bubbles can be continuous, independent, semi-continuous, or a combination of these. By having a continuous internal air bubble configuration, the buffering and compressibility can be further enhanced. By having an independent internal air bubble configuration, the heat insulation can be further enhanced. In a semi-continuous internal air bubble configuration, the air bubbles have small pores, and adjacent air bubbles can communicate with each other through these small pores. Here, the size of the air bubbles is preferably 60 μm or more and 200 μm or less, and the size of the pores is preferably 1 μm or more and 50 μm or less.

[0045] As porous sheets, sheets formed from porous resins such as silicone foam, polyolefin foam, urethane foam, polystyrene foam, ethylene vinyl acetate copolymer foam, polyethylene terephthalate foam, polyvinyl chloride foam, polyimide foam, polyamide foam, acrylic foam, fluororesin foam, phenol foam, melamine foam, ethylene propylene diene rubber foam, and chloroprene rubber foam can be used. Among these, polyolefin foam, polystyrene foam, and urethane foam are preferred, and urethane foam is more preferred, as they have excellent shock absorption and stress relaxation effects.

[0046] Commercially available polyolefin foams include "P·E-Lite (registered trademark)" from Inoac Corporation, "Sunpelka (registered trademark)" from Sanwa Kako Co., Ltd., "Softlon (registered trademark)" from Sekisui Chemical Co., Ltd., "High Ethylene" from Resonac Techno Service Co., Ltd., "Suntech Foam (registered trademark)" from Asahi Kasei Corporation, "Toraypef (registered trademark)" from Toray Industries, Inc., "Foam Ace (registered trademark)" and "F-Cell (registered trademark)" from Furukawa Electric Co., Ltd., and "Miramat (registered trademark)" and "ARPRO (registered trademark)" from JPS Corporation. Commercially available polystyrene foams include "Styrofoam (registered trademark)" from DuPont Styrofoam Co., Ltd. and "Styrodia (registered trademark)" from JSP Corporation. Commercially available polyurethane foams include "SlimFlex (registered trademark)" from Inoac Corporation, "Everlight (registered trademark)" from Arcem Co., Ltd., and "Achilles Aeron (registered trademark)" from Achilles Corporation. In particular, from the perspective of achieving both cushioning and heat insulation, the "SlimFlex®" RX series manufactured by Inoac Corporation, which is a semi-continuous cell polyurethane foam with a semi-continuous internal cell structure, is preferred.

[0047] The method for manufacturing urethane foam is not particularly limited, but it can be manufactured by known methods. For example, it can be manufactured by mixing a polyol such as polyester polyol, polycarbonate polyol, polyether polyol, polyester ether polyol with an isocyanate such as aromatic isocyanate, aliphatic isocyanate, or alicyclic isocyanate, a catalyst, and optionally a blowing agent, foam stabilizer, antioxidant, surfactant, dispersion medium, flame retardant, and inorganic particles, and then foaming and curing. The foaming method is not particularly limited, but a method using a chemical blowing agent or a mechanical flossing method in which gas is mechanically mixed can be used. From the viewpoint of flame resistance, it is preferable that the urethane foam has excellent flame retardancy, and it is preferable to select a urethane foam that meets the V-0 grade of the US UL-94 standard.

[0048] The buffer layer 102 may contain inorganic particles, organic particles, inorganic fibers, organic fibers, thermal expansion agents, plasticizers, colorants, antioxidants, antistatic agents, and flame retardants, to the extent that it does not impair the buffering effect.

[0049] Examples of flame retardants include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, zirconium hydroxide, tin oxide, aluminum oxide, magnesium oxide, nickel oxide, molybdenum oxide, titanium oxide, zinc oxide, expanded graphite, calcium carbonate, magnesium carbonate, barium carbonate, zinc carbonate, zinc borate, ammonium polyphosphate, ammonium phosphate, aluminum phosphite, aluminum diethylphosphinate, antimony trioxide, red phosphorus, melamine, melamine cyanurate, trialkylphosphine oxide, triphenylphosphine oxide, cyanuric acid compounds, isocyanuric acid compounds, tetrazole compounds, diazo compounds, phosphate ester compounds, phosphate ester amide compounds, phosphazene compounds, guanidine compounds, and silicone compounds. From the viewpoint of reducing environmental impact, it is preferable to use non-halogenated flame retardants. Flame retardants may be used individually or in combination of two or more types. In particular, from the viewpoint of flame retardancy, phosphorus-based flame retardants such as ammonium polyphosphate, ammonium phosphate, aluminum phosphite, aluminum diethylphosphinate, trialkylphosphine oxide, triphenylphosphine oxide, phosphate ester compounds, phosphate ester amide compounds, and phosphazene compounds are preferred, and it is preferable to include both a phosphorus-based flame retardant and expanded graphite.

[0050] Expandable flame retardants such as aluminum phosphite and expanded graphite expand when heated, and therefore function not only as flame retardants but also as thermal expansion agents. For example, when expanded graphite is heated, the gas generated from between the graphite layers expands the interlayers, thus improving thermal insulation. Expanded graphite can be produced by known methods. For example, powders of natural graphite or pyrolysis graphite are treated with inorganic acids such as sulfuric acid and nitric acid, and strong oxidizing agents such as perchloric acid, permanganate, and hydrogen peroxide to facilitate the insertion of these inorganic acids between the graphite layers, generating graphite interlayer compounds, which are then produced through processes such as neutralization.

[0051] Preferably, the expanded graphite has an expansion initiation temperature of 130°C or higher and 300°C or lower. If the expansion initiation temperature is 130°C or higher, unexpected expansion can be prevented during the manufacturing process of the buffer layer 102 and the thermal insulation laminate 100, as well as during normal use around the battery cells. If the expansion initiation temperature is 300°C or lower, it can expand under high-temperature conditions to improve thermal insulation. Furthermore, when the buffer layer 102 is urethane foam, it can expand at temperatures at which the urethane foam melts or decomposes, making it easier to expand and further improving thermal insulation.

[0052] The expanded graphite content is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 30% by mass or less, when the entire buffer layer 102 is considered to be 100% by mass. If the expanded graphite content is 5% by mass or more, flame retardancy and heat insulation properties are easily exhibited. If the expanded graphite content is 50% by mass or less, buffering properties are easily maintained.

[0053] The average diameter of the expanded graphite before expansion is preferably 50 μm or more and 500 μm or less. If it is 50 μm or more, it has good expandability, and if it is 500 μm or less, it has good dispersibility when added to the buffer layer 102.

[0054] The buffer layer 102 can be given expandability by other thermal expansion agents, not just expanded graphite, to form an air insulation layer. The expansion rate of the buffer layer 102 is preferably 200% or more and 400% or less in the thickness direction after being exposed to a 1300°C flame for 5 minutes. If the expansion rate is 200% or more, an air insulation layer can be formed by the expansion, improving the insulation performance. If the expansion rate is 400% or less, the stress on the surrounding members can be suppressed by the expansion.

[0055] The buffer layer 102 has an apparent density of 0.1 g / cm³. 3 More than 1g / cm 3 Preferably, it is 0.2 g / cm³. 3 More than 0.5g / cm 3 It is more preferable that the apparent density is 0.1 g / cm³. 3 If the above is true, it has sufficient strength to function as a buffer layer, 1g / cm³ 3 The following materials are lightweight, flexible, and possess excellent cushioning and compressibility properties. The apparent density can be calculated by dividing the weight of a 20cm square sheet of sample, measured on an electronic balance, by the volume calculated by measuring the dimensions of the sample with calipers and a micrometer.

[0056] From the viewpoint of making the buffer layer 102 less susceptible to the effects of deformation and volume changes of surrounding members such as the battery cell 201, and making it difficult for pressure to propagate to adjacent members, the 25% compressive stress of the buffer layer 102 is preferably 5 MPa or less, more preferably 1 MPa or less, and even more preferably 0.1 MPa or less. The 25% compressive stress can be measured in the same manner as shown in the examples.

[0057] From the viewpoint of maintaining cushioning properties and ensuring that the protective performance of adjacent members is maintained even when deformation and volume changes occur repeatedly in the surrounding members, the 50% compression set of the buffer layer 102 is preferably 30% or less, more preferably 10% or less, and even more preferably 1% or less. The 50% compression set can be measured in the same manner as shown in the examples.

[0058] The thickness of the buffer layer 102 is not particularly limited, but from the viewpoint of ensuring sufficient buffering performance, it is preferably 0.05 mm or more, and more preferably 0.5 mm or more. From the viewpoint of roll-to-roll processability and space saving when manufacturing the thermal insulation laminate, it is preferably 10 mm or less, and more preferably 3 mm or less.

[0059] From the viewpoint of ensuring the shock absorption and stress relaxation properties of the entire thermal insulation laminate 100, the thickness of the buffer layer 102 is preferably 40% or more of the total thickness of the thermal insulation laminate 100, more preferably 60% or more, and preferably thicker than the thermal insulation layer 101.

[0060] The intermediate layer 103 is provided between the flame-shielding layer 101 and the buffer layer 102. The intermediate layer 103 normally maintains the shape of the flame-shielding layer 101 and the buffer layer 102 as a single unit, preventing peeling or detachment of the flame-shielding layer 101 or the buffer layer 102 during the manufacturing process or normal use. Furthermore, it can be configured to expand and form an air insulation layer if the flame-shielding layer 101 or the buffer layer 102 becomes hot due to thermal runaway of the battery cell 201, etc. It can also be configured so that at least a portion of the intermediate layer 102 disappears when it becomes hot.

[0061] The intermediate layer 103 can be, for example, a resin layer. It is preferable to form it from an adhesive material so that it adheres closely to and becomes one with the flame-shielding layer 101 and the buffer layer 102 under normal conditions. For example, it can be a thermosetting resin, thermoplastic resin, thermosetting elastomer, thermoplastic elastomer, etc., and may or may not have a chemical or physical crosslinking structure. In particular, from the viewpoint of adhesion and flexibility, it is preferable to include an elastomer that exhibits at least one glass transition temperature in a temperature range of -150°C or higher and 30°C or lower. The glass transition temperature can be measured by thermomechanical analysis (TMA), differential scanning calorimetry (DSC), or dynamic viscoelasticity measurement (DMA). For example, it can be measured using a differential scanning calorimetry (DSC) in accordance with ASTM D3418.

[0062] The weight-average molecular weight of the elastomer is not particularly limited, but is preferably 10,000 or more, more preferably 40,000 or more, preferably 1,000,000 or less, and more preferably 400,000 or less. A weight-average molecular weight of 10,000 or more makes it easier to obtain good adhesion. A weight-average molecular weight of 1,000,000 or less makes it easier to obtain good adhesion. For example, when the intermediate layer contains a thermal expansion agent or an expandable flame retardant, the fluidity of the intermediate layer is more easily improved under high-temperature conditions, and the intermediate layer is more easily expanded, so an air insulation layer is easily formed and an improvement in insulation performance can be expected. The weight-average molecular weight can be measured by gel permeation chromatography (GPC).

[0063] Examples of elastomers include silicone elastomers, olefin elastomers, acrylic elastomers, and urethane elastomers. Thermoplastic acrylic elastomers are preferred because they offer excellent adhesion and flexibility, and at least a portion of them disappears at high temperatures, further enhancing their heat-insulating properties. Examples of acrylic elastomers include copolymers of (meth)acrylic acid ester and acrylonitrile, copolymers of (meth)acrylic acid ester and ethylene, and copolymers of (meth)acrylic acid ester and other (meth)acrylic acid esters. Among these, copolymers of (meth)acrylic acid ester and ethylene are more preferred. The (meth)acrylic acid ester may be used alone or in combination of two or more types.

[0064] Commercially available acrylic elastomers include "Clarity®" from Kuraray Co., Ltd., "NanoStrength®" from Arkema K.K., "Teisan Resin®" from Nagase ChemteX Corporation, "Vamac®" from DuPont, and the "Nipol®" AR series from Zeon Corporation. Silicone elastomers have siloxane bonds, resulting in high heat resistance and resistance to disappearance at high temperatures. Therefore, when used in the intermediate layer 103, it is difficult to achieve improved thermal insulation due to the disappearance of at least a portion of the silicone elastomer. For this reason, from the viewpoint of achieving greater thermal insulation by having at least a portion of the silicone elastomer disappear, olefin elastomers, acrylic elastomers, and urethane elastomers that do not contain silicone elastomers are more preferable. From the viewpoint of ease of handling and productivity during processing, it is preferable that the intermediate layer 103 is a material that has low tackiness under room temperature conditions and exhibits adhesiveness and tackiness when heated for a short time at temperatures between 50°C and 100°C. The intermediate layer 103 can also be formed from a material that does not have adhesive or tackiness properties.

[0065] From a productivity standpoint, it is preferable to prepare an intermediate layer in advance, sandwich the intermediate layer between the flame-retardant layer 101 and the buffer layer 102, and perform roll lamination or lamination press processing to form a thermal insulation laminate 100 in which the intermediate layer 103 is in close contact with the flame-retardant layer 101 and the buffer layer 102. In this case, it is possible to use an elastomer that does not have a crosslinking structure at the intermediate layer formation stage but develops crosslinking when the thermal insulation laminate 100 is formed, or to use an elastomer that is crosslinked at the intermediate layer formation stage, or to use an elastomer that does not have a crosslinking structure at the intermediate layer formation stage and does not crosslink even when the thermal insulation laminate 100 is formed. Chemically non-crosslinked elastomers are preferable in terms of storage management and productivity because they have excellent stability in the intermediate layer formation state.

[0066] The method for manufacturing the intermediate layer is not particularly limited, but can be manufactured by known methods. For example, it can be manufactured by adding inorganic particles, organic particles, inorganic fibers, organic fibers, thermal expansion agents, and flame retardants as needed to a resin selected from thermosetting resins, thermoplastic resins, thermosetting elastomers, thermoplastic elastomers, etc., dispersing or dissolving it with an organic solvent such as toluene, methyl ethyl ketone, or cyclohexane, coating it onto a release substrate to a desired thickness, and heating to remove the organic solvent. The release substrate is not particularly limited, but can be a substrate such as polyester film, polyolefin film, fluororesin film, or paper, or a substrate on which a release agent layer such as silicone, polyolefin, alkyd resin, or fluororesin is provided on the surface of these substrates. The coating method is not particularly limited, but can be a known method. For example, it can be selected from roll coating, bar coating, knife coating, knife roll coating, air knife coating, blade coating, die coating, lip coating, gravure coating, comma coating, spin coating, spray coating, etc., and other methods such as impregnation into nonwoven or woven fabrics are also acceptable.

[0067] The temperature for heating and drying the solvent is preferably 50°C to 130°C, and more preferably 60°C to 120°C. The intermediate layer forming layer is preferably manufactured continuously using a roll-to-roll method, as this is expected to reduce manufacturing costs. If necessary, another release substrate may be laminated onto the surface of the intermediate layer forming layer to prevent contamination during storage. One method for laminating another release substrate is, for example, roll lamination at a temperature of 20°C to 60°C and a pressure of 0.1 MPa to 1 MPa. When sandwiching the intermediate layer forming layer between the flame-shielding layer 101 and the buffer layer 102, the material with the release substrate removed can be used as the intermediate layer forming layer.

[0068] The intermediate layer 103 may be a layer containing inorganic particles, organic particles, inorganic fibers, organic fibers, a thermal expansion agent, and a flame retardant, etc.

[0069] As the flame retardant, the same flame retardants as those used in the buffer layer described above can be used. These flame retardants may be used individually or in combination of two or more types. Among these, phosphorus-based flame retardants are preferred, and when an elastomer is used in the intermediate layer 103, phosphinate metal salt-based flame retardants such as aluminum diethylphosphinate are even more preferred from the viewpoint of compatibility with the elastomer.

[0070] The flame retardant content is preferably 10% by mass or more and 60% by mass or less, more preferably 30% by mass or more and 50% by mass or less, and even more preferably 35% by mass or more and 45% by mass or less, when the entire intermediate layer 103 is considered to be 100% by mass. A flame retardant content of 30% by mass or more makes it easier to exhibit sufficient flame retardancy. A flame retardant content of 50% by mass or less makes it easier to maintain adhesion and suppress the bleed-out of the flame retardant.

[0071] Furthermore, the intermediate layer 103 can also improve thermal insulation by expanding to form an air insulation layer, and therefore may contain a thermal expansion agent or expanded graphite. As the thermal expansion agent, a microcapsule-type thermal expansion agent in which a compound that expands upon heating is encapsulated in a shell made of thermoplastic resin may be used, and as the expanded graphite, expanded graphite produced by the known method described above may be used. In addition, other expandable flame retardants or thermally expandable layered inorganic materials may be used.

[0072] From the viewpoint of preventing ignition from the thermal insulation laminate, it is preferable that the intermediate layer contains a flame retardant. However, from the viewpoint of further enhancing thermal insulation by having at least a portion of the intermediate layer 103 disappear when exposed to high temperatures, it is also possible to have a configuration that does not contain particles, fibers, flame retardants, etc.

[0073] The resin material forming the intermediate layer 103 preferably has a decomposition temperature of 600°C or lower, and more preferably 500°C or lower, from the viewpoint of making it easily disappear when exposed to high temperatures. On the other hand, to prevent it from disappearing under normal conditions, it preferably has a decomposition temperature of 100°C or higher, and more preferably 200°C or higher. The decomposition temperature of the resin material can be measured, for example, by thermogravimetric analysis such as TGA or TG-DTA.

[0074] It is preferable that the intermediate layer 103, the flame-retardant layer 101, and the buffer layer 102 are in close contact without any gaps, so that when the flame-retardant layer 101 or the buffer layer 102 becomes hot, heat is quickly transferred to the intermediate layer 103, and at least a portion of the intermediate layer disappears, thereby exhibiting an improved heat insulation effect. The flame-retardant layer 101 and the buffer layer 102 may be fibrous or porous, and the surfaces of these layers may have irregularities. In such cases, it is preferable that the intermediate layer 103 can deform to conform to the irregularities of the surface and be in close contact.

[0075] The thickness of the intermediate layer 103 is preferably 0.001 mm or more, more preferably 0.01 mm or more, and even more preferably 0.02 mm or more, from the viewpoint of ensuring the integrity of the flame-retardant layer 101 and the buffer layer 102. Furthermore, from the viewpoint of facilitating the formation of an air-insulating layer by disappearing, it is preferably 1 mm or less, more preferably 0.3 mm or less, and even more preferably 0.2 mm or less. In addition, it is preferable that the intermediate layer 103 is thinner than the buffer layer 102.

[0076] The thermal insulation laminate 100 can be formed by sandwiching a pre-formed intermediate layer forming sheet between a flame-retardant layer forming sheet that will become the flame-retardant layer 101 and a buffer layer forming sheet that will become the buffer layer 102, and then roll laminating or laminating by pressing. The intermediate layer forming sheet, the flame-retardant layer forming sheet, and the buffer layer forming sheet are sheets formed from the materials that constitute each layer. The heating temperature for roll lamination or lamination by pressing is not particularly limited, but is preferably 40°C or higher and 120°C or lower, and more preferably 60°C or higher and 100°C or lower. By heating to 60°C or higher, the layers can be bonded together and become more integrated, and by heating to 100°C or lower, deterioration and unexpected reactions during the manufacturing process of the thermal insulation laminate 100 can be made less likely, and productivity can be further improved.

[0077] The press pressure for roll lamination and lamination pressing is not particularly limited, but is preferably 0.01 MPa or more and 10 MPa or less, and more preferably 0.1 MPa or more and 1 MPa or less. By setting the press pressure to 0.1 MPa or more, the layers can be bonded together and become more integrated. By setting it to 1 MPa or less, deformation of each layer during the manufacturing process of the thermal insulation laminate 100 can be made less likely, and if the intermediate layer forming sheet contains components that flow easily under heating conditions, it is possible to suppress the penetration of the material constituting the intermediate layer forming sheet into the flame-shielding layer forming sheet and / or the buffer layer forming sheet to the extent that it impairs the function of each layer, thus resulting in excellent productivity. In addition, by roll lamination using a roll-to-roll method, it is possible to simplify the manufacturing process and reduce manufacturing costs. Not limited to these methods, it is also possible to form the laminate by sequentially laminating other layers on top of the flame-shielding layer 101 or the buffer layer 102, or by integral molding by multi-color molding, etc.

[0078] Figure 1 shows an insulating laminate 100 consisting of three layers: a flame-retardant layer 101, an intermediate layer 103, and a buffer layer 102. However, a configuration with four or more layers can also be used. For example, an insulating laminate 100A with a five-layer structure consisting of a flame-retardant layer 101, an intermediate layer 103, a buffer layer 102, an intermediate layer 103, and a flame-retardant layer 101 can be used, as shown in Figure 3. Alternatively, an insulating laminate 100B with a five-layer structure consisting of a buffer layer 102, an intermediate layer 103, a flame-retardant layer 101, an intermediate layer 103, and a buffer layer 102 can be used, as shown in Figure 4. Furthermore, a multi-layer configuration is also possible. In addition, a functional layer can be provided between the outer flame-retardant layer 101 or buffer layer 102 and the member in contact with the insulating laminate to fix the insulating laminate to the target member or improve adhesion. The functional layer is not particularly limited, but can be a layer with the same composition and structure as the intermediate layer 103.

[0079] When the thermal insulation laminate includes multiple flame-retardant layers 101, buffer layers 102, and intermediate layers 103, the flame-retardant layers 101, buffer layers 102, and intermediate layers 103 can each be layers of the same thickness made of the same material. Alternatively, they can each be layers made of different materials or layers of different thicknesses.

[0080] In addition to the flame shielding layer 101, the buffer layer 102, and the intermediate layer 103, the heat insulation laminate can be configured to have functional layers such as an insulating layer, a heat conduction layer, a heat absorption layer, a dustproof layer, and a moisture-proof layer.

[0081] From the perspective of ensuring heat insulation and buffering properties, the thickness of the entire heat insulation laminate is preferably 0.1 mm or more, more preferably 0.5 mm or more, and even more preferably 1 mm or more. From the perspective of ease of manufacturing and space saving, it is preferably 20 mm or less, more preferably 10 mm or less, and even more preferably 4 mm or less.

[0082] The density of the entire heat insulation laminate is preferably 1 g / cm 3 or less from the perspective of weight reduction, and more preferably 0.5 g / cm 3 or less. From the perspective of handling properties, it is preferably 0.1 g / cm 3 or more, and more preferably 0.3 g / cm 3 or more.

[0083] The 25% compression stress of the entire heat insulation laminate is preferably 5 MPa or less, more preferably 1 MPa or less, and even more preferably 0.1 MPa or less from the perspective of being less affected by deformation and volume change and less likely to transmit pressure to adjacent members.

[0084] The 50% compression permanent strain of the entire heat insulation laminate is preferably 30% or less, more preferably 10% or less, and even more preferably 1% or less from the perspective of maintaining the protective performance of adjacent members even when volume changes are repeated.

[0085] The dielectric breakdown voltage of the entire heat insulation laminate is preferably 1 kV / mm or more, and more preferably 1.5 kV / mm or more in applications where electrical insulation such as in a battery unit is required.

[0086] The flame retardancy of the entire heat insulation laminate preferably satisfies the V-0 grade of the US UL94 standard from the perspective of preventing flame spread.

[0087] It is preferable that the thermal insulation laminate as a whole has sufficient flame-retardant properties. Flame-retardant properties can be evaluated by visually checking whether penetration occurs on the opposite side when a 1300°C flame is applied to one side of the thermal insulation laminate for 5 minutes.

[0088] It is preferable that the thermal insulation laminate as a whole has sufficient thermal insulation properties. The thermal insulation properties can be evaluated by checking whether the surface temperature of the opposite side of the thermal insulation laminate is 400°C or less, preferably less than 350°C, when a 1300°C flame is applied to one side of the laminate for 5 minutes.

[0089] The thermal insulation laminate of this disclosure can be used in various applications where thermal insulation and buffering properties are required. For example, as shown in Figure 2, it can be used as thermal insulation for a battery unit that integrates multiple battery cells 201, and can be used as a material to prevent heat transfer and fire spread even under high temperature conditions of around 1000°C or temperature conditions below 1000°C. It is also useful as thermal insulation for electronic equipment, buildings, vehicles, cables, etc.

[0090] The thermal insulation laminates of this disclosure will be described in more detail using examples. Note that the following examples are illustrative and are not intended to limit the present invention. [Examples]

[0091] <density> The density of the thermal insulation laminate was calculated from the apparent density and thickness of each layer.

[0092] <Flame-retardant> The tests were conducted in accordance with the US UL94 standard for vertical combustion testing. A rating was given if the test results met the V-0 standard, and a rating of B if they did not.

[0093] <Flame blocking properties> A 1300°C flame was applied to one side of a 50mm square sample for 5 minutes. The flame was generated using a Power Gas RZ-760 and Power Torch RZ-730S manufactured by Shin Fuji Burner Co., Ltd. The distance from the burner tip to the flame-contact surface of the sample was set to 5cm, and a concentrated 1300°C flame was applied to the sample surface. In the case of laminates with a flame-resistant layer, the flame was applied to the surface of the flame-resistant layer. Afterwards, the condition of the opposite side was observed visually. A rating was given if there were no penetrations, and a rating of B if there were penetrations.

[0094] <Expandability> The thickness of the sample used for flame resistance evaluation was defined as t0 before flame contact, and the thickness of the sample 5 minutes after contact with the flame was defined as t5. The expansion rate was calculated using the following formula. Expansion rate (%) = t5 / t0 × 100 In the case of a laminate with a flame-resistant layer, the flame was brought into contact with the surface of the flame-resistant layer.

[0095] <Thermal insulation> A 1300°C flame was applied to one side of a 50mm square sample, and the surface temperature of the opposite side was measured using a K-type thermocouple. The flame was generated using a Power Gas RZ-760 and Power Torch RZ-730S manufactured by Shin Fuji Burner Co., Ltd. The distance from the burner tip to the flame-contacting surface of the sample was set to 5cm, and a concentrated 1300°C flame was applied to the sample surface. The surface temperature of the opposite side after 5 minutes of contact with the flame was defined as the thermal insulation evaluation temperature. In the case of laminates with a flame-shielding layer, the flame was applied to the surface of the flame-shielding layer.

[0096] <Insulating properties> The dielectric breakdown voltage of a 50mm square sample was measured using an ultra-high voltage withstand voltage tester (7473, manufactured by Keisoku Gijutsu Kenkyusho Co., Ltd.). Under conditions of 23°C and 55% relative humidity, the voltage was applied from 0V to 20kV at a boost rate of 500V per second, and the dielectric breakdown voltage was measured.

[0097] <Compressibility> Samples cut into 15mm squares were compressed by 25% in the thickness direction using a Strograph (VGS05-E, manufactured by Toyo Seiki Seisakusho Co., Ltd.) to determine the 25% compressive stress. Measurements were performed under conditions of 23°C and 55% relative humidity. A rating was given for 25% compressive stress of 0.1 MPa or less, and a rating of B was given for 25% compressive stress greater than 0.1 MPa.

[0098] <Restorability> After measuring the initial thickness t1 of a 15mm square sample, it was compressed by 50% in the thickness direction using a jig and left to stand for 24 hours at a temperature of 23°C and a relative humidity of 55%. The sample was then removed from the jig and left to stand for 30 minutes without load at a temperature of 23°C and a relative humidity of 55%, and the thickness t2 was measured after the test. The 50% permanent compression strain was calculated from the values ​​of t1 and t2 using the following formula. A rating of A was given if the 50% permanent compression strain was 1% or less, and a rating of B was given if the 50% permanent compression strain was greater than 1%.

[0099] 50% compression set (%) = (t1 - t2) / t1 × 100

[0100] (Laminate 1) The flame-retardant layer-forming sheet has an inorganic particle layer formed on its surface, with a thermal conductivity of 0.1 W / m·K and an apparent density of 0.56 g / cm³. 3 The buffer layer was made of a glass fiber nonwoven fabric with a thickness of 0.31 mm. The buffer layer forming sheet contained expanded graphite, with a thermal conductivity of 0.05 W / m·K and an apparent density of 0.31 g / cm³. 3 A semi-continuous cell urethane foam with a thickness of 2.0 mm was used. The intermediate layer forming sheet had a thermal conductivity of 0.1 W / m·K and an apparent density of 1.1 g / cm³. 3A 0.025 mm thick acrylic elastomer sheet was used. The intermediate layer sheet was formed as follows: First, 18 parts by mass of ethylene-methyl acrylate copolymer with a glass transition temperature of -28°C and a weight-average molecular weight of approximately 260,000, 12 parts by mass of aluminum diethylphosphinate, and 70 parts by mass of a mixed solvent of toluene and methyl ethyl ketone were mixed to form a mixture. The formed mixture was coated onto a release substrate using a baker-type applicator, dried at 120°C to remove the mixed solvent, and then peeled off the release substrate to obtain the intermediate layer sheet. The flame-resistant layer sheet, the intermediate layer sheet, and the buffer layer sheet were laminated in this order and roll-laminated at 80°C, 0.3 MPa, and 1 m / min to create a sample of a three-layer thermal insulation laminate having a flame-resistant layer, an intermediate layer, and a buffer layer.

[0101] The density of the thermal insulation laminate, determined from the apparent density and thickness of each layer of forming sheet, is 0.35 g / cm³. 3 The results were as follows: Flame retardancy was rated A, flame shielding was rated A, expansion coefficient was 263%, thermal insulation evaluation temperature was 254.6℃, dielectric breakdown voltage was 1.75kV / mm, compressibility was rated A, and resilience was rated A.

[0102] (Laminate 2) The acrylic elastomer sheet used for the intermediate layer formation sheet was perforated in the same manner as in Example 1, except that φ6 mm through holes were made at equal intervals across the entire surface of the sheet, with the shortest distance between the centers of the through holes being 10 mm.

[0103] The density of the thermal insulation laminate, determined from the apparent density and thickness of each layer of forming sheet, is 0.35 g / cm³. 3 The results were as follows: Flame retardancy was rated A, flame shielding was rated A, expansion coefficient was 261%, thermal insulation evaluation temperature was 253.2℃, dielectric breakdown voltage was 1.97kV / mm, compressibility was rated A, and resilience was rated A.

[0104] (Laminate 3) The procedure was the same as in Example 1, except that the thickness of the acrylic elastomer sheet used for the intermediate layer formation sheet was set to 0.10 mm.

[0105] The density of the thermal insulation laminate, determined from the apparent density and thickness of each layer of forming sheet, is 0.37 g / cm³. 3 The results were as follows: Flame retardancy was rated A, flame shielding was rated A, expansion coefficient was 250%, thermal insulation evaluation temperature was 230.5℃, dielectric breakdown voltage was 2.17kV / mm, compressibility was rated A, and resilience was rated A.

[0106] (Laminate 4) The procedure was the same as in Example 1, except that the thickness of the acrylic elastomer sheet used for the intermediate layer formation sheet was set to 0.20 mm.

[0107] The density of the thermal insulation laminate, determined from the apparent density and thickness of each layer of forming sheet, is 0.40 g / cm³. 3 The results were as follows: Flame retardancy was rated A, flame shielding was rated A, expansion coefficient was 252%, thermal insulation evaluation temperature was 281.6℃, dielectric breakdown voltage was 1.98kV / mm, compressibility was rated A, and resilience was rated A.

[0108] (Laminate 5) A flame-retardant layer-forming sheet has an inorganic particle layer formed on its surface, with a thermal conductivity of 0.1 W / m·K and an apparent density of 0.61 g / cm³. 3 The procedure was the same as in Example 1, except that a glass fiber nonwoven fabric with a thickness of 0.16 mm was used.

[0109] The density of the thermal insulation laminate, determined from the apparent density and thickness of each layer of forming sheet, is 0.34 g / cm³. 3 The results were as follows: Flame retardancy was rated A, flame shielding was rated A, expansion coefficient was 300%, thermal insulation evaluation temperature was 304.3℃, dielectric breakdown voltage was 1.81kV / mm, compressibility was rated A, and resilience was rated A.

[0110] (Laminate 6) The procedure was the same as in Example 1, except that the flame-retardant layer-forming sheet was a mica sheet formed by integrating rigid laminated mica with a silicone adhesive. The thermal conductivity of the flame-retardant layer-forming sheet was 0.2 W / m·K, and the apparent density was 2.1 g / cm³. 3 The thickness was 0.18 mm.

[0111] The density of the thermal insulation laminate, determined from the apparent density and thickness of each layer of forming sheet, is 0.47 g / cm³. 3 The results were as follows: Flame retardancy was rated A, flame shielding was rated A, expansion coefficient was 309%, thermal insulation evaluation temperature was 280.7℃, dielectric breakdown voltage was 2.17kV / mm, compressibility was rated A, and resilience was rated A.

[0112] (Laminate 7) The intermediate layer forming sheet has an apparent density of 1.1 g / cm³. 3 The procedure was the same as in Example 1, except that a 0.050 mm thick silicone tape (Transil NT-1001, a double-sided silicone adhesive tape manufactured by Taiyo Kanami Co., Ltd.) was used.

[0113] The density of the thermal insulation laminate, determined from the apparent density and thickness of each layer of forming sheet, is 0.36 g / cm³. 3 The results were as follows: Flame retardancy was rated A, flame shielding was rated A, expansion coefficient was 291%, thermal insulation evaluation temperature was 356.5℃, dielectric breakdown voltage was 1.93kV / mm, compressibility was rated A, and resilience was rated A.

[0114] (Single layer 1) Expanded graphite is included, with a thermal conductivity of 0.05 W / m·K and an apparent density of 0.31 g / cm³. 3 A single-layer structure of 2.0 mm thick semi-open-cell polyurethane foam was evaluated in the same way as the laminated structure. In the evaluation of flame resistance, penetration points could not be visually confirmed, and due to severe damage to the sample, it was not possible to evaluate the expansion properties.

[0115] The material received an A rating for flame retardancy, an A rating for fire protection, an A rating for thermal insulation (evaluation temperature: 514.9°C), an A rating for dielectric breakdown voltage (2.05kV / mm), an A rating for compressibility, and an A rating for resilience.

[0116] (Single layer 2) A single-layer structure of glass fiber nonwoven fabric with an inorganic particle layer formed on its surface, having a thermal conductivity of 0.1 W / m·K, an apparent density of 0.56 g / cm³, and a thickness of 0.31 mm, was evaluated in the same way as the laminated structure. Since the single-layer structure of the glass fiber nonwoven fabric could not be compressed, its compressibility and resilience could not be evaluated.

[0117] The flame retardancy was rated A, the flame shielding was rated A, the expansion coefficient was 100%, and the dielectric breakdown voltage was 6.31 kV / mm. In the thermal insulation evaluation, the surface temperature on the opposite side exceeded 800°C and reached 822.5°C after 30 seconds, so the thermal insulation evaluation temperature after 5 minutes was not measured.

[0118] The evaluation results for the laminated and single-layer structures are summarized in Tables 1 and 2.

[0119] [Table 1]

[0120] [Table 2]

[0121] Figure 5 shows the change in surface temperature (back surface temperature) on the opposite side when a 1300°C flame was applied to laminates 1, 2, 3, and 7, and single layers 1 and 2. Laminates 1-3 showed a slower temperature increase compared to the other samples, and did not exceed 300°C even after 600 seconds.

[0122] Furthermore, when the condition of the samples of laminates 1 and 7 was examined after contact with a flame for 5 minutes, the adhesion of the intermediate layer in laminate 1 was significantly reduced compared to laminate 7. From this, it is presumed that in laminate 1, at least a portion of the intermediate layer disappeared, forming a sufficient air insulation layer, which resulted in a lower thermal insulation evaluation temperature than that of laminate 7.

[0123] Figure 6 shows the results of the thermal insulation evaluation of laminate 1 when the flame temperature applied was 1300°C and 1500°C. At 1500°C, the surface temperature of the opposite side (back surface temperature) was higher than at 1300°C, but it was still possible to maintain a temperature of approximately 400°C even after 5 minutes. Furthermore, no penetrations were observed in the sample, confirming that it possesses sufficient flame-retardant properties. The 1500°C flame was generated using a Power Gas RZ-850 and Power Torch RZ-820 manufactured by Shin Fuji Burner Co., Ltd., with a distance of 7 cm from the burner tip to the surface of the sample. [Industrial applicability]

[0124] The thermal insulation laminate of this disclosure has excellent cushioning, thermal insulation, and flame-retardant properties, and is useful as a thermal insulation material between heat-generating components. [Explanation of symbols]

[0125] 100 Thermal insulation laminate 100A Insulated Laminate 100B Insulated Laminate 101 Flameproof layer 102 Buffer layer 103 Middle Class 201 battery cells 202 enclosures

Claims

1. Flame-blocking layer, Buffer layer, The intermediate layer is provided between the flame-blocking layer and the buffer layer and is in close contact with the flame-blocking layer and the buffer layer. When a flame of 1300°C is brought into contact with the exposed surface of the flame-blocking layer or the buffer layer for 5 minutes, the surface temperature of the surface opposite to the surface that was in contact with the flame is less than 350°C. The flame retardancy rating when tested in accordance with the US UL94 standard is V-0. The flame-blocking layer is a layer comprising at least one selected from inorganic particles, inorganic fibers, and inorganic porous materials. The aforementioned intermediate layer is a resin layer containing an acrylic elastomer. The aforementioned buffer layer is made of urethane foam. Thermal insulation laminate.

2. The thermal insulation laminate according to claim 1, wherein the intermediate layer and / or the buffer layer contains at least one flame retardant selected from phosphorus-based flame retardants and expansive flame retardants.

3. The heat insulating laminate according to claim 1, wherein the flame-shielding layer is a glass fiber nonwoven fabric or a mica sheet.

4. The thermal insulation laminate according to claim 1, wherein the buffer layer is a layer formed of a porous resin.

5. The thermal insulation laminate according to claim 1, wherein the dielectric breakdown voltage is 1.5 kV / mm or more.

6. The thermal insulation laminate according to claim 1, wherein the 25% compressive stress is 0.1 MPa or less and the 50% compression set is 1% or less.

7. Density is 0.1 g / cm³ ３ Above, 1g / cm ３ The thermal insulation laminate according to claim 1, which is as follows:

8. A thermal insulation laminate according to any one of claims 1 to 7, Equipped with multiple battery cells, The thermal insulation laminate is positioned at least between a plurality of battery cells in a battery unit.

Images