Laminate

Abstract

To provide a laminate that has sufficient moldability, excellent lightweight properties, and can also exhibit high flame-retardant performance. [Solution] A laminate comprising a flame-shielding layer containing a first inorganic fiber and resin A having a melting point of 1000°C or higher, and a fiber layer containing fibers on at least one surface of the flame-shielding layer.

Description

[Technical Field]

[0001] This invention relates to a laminate. [Background technology]

[0002] In recent years, there has been a growing demand for longer driving ranges in electric vehicles, and for this reason, attempts are being made to densely pack various types of batteries, such as lithium-ion batteries. However, various types of batteries, such as lithium-ion batteries, carry the risk of overheating and ignition due to internal short circuits or other issues. In particular, in the case of automotive batteries, impacts such as those from vehicle accidents can cause the battery to overheat and ignite, potentially leading to a vehicle fire. Therefore, the cover surrounding the battery needs to be designed to prevent the heat from the battery, which becomes abnormally hot due to overheating, from being transferred to the surroundings, and to prevent flames generated by battery ignition from being transmitted to the outside.

[0003] As a cover for such an in-vehicle battery, for example, Patent Document 1 discloses a battery case made of a metal material such as iron or aluminum. Furthermore, Patent Document 2 discloses a vehicle battery case made of a metal material such as aluminum alloy or stainless steel as a base material. Furthermore, Patent Document 3 describes an in-vehicle battery housing composed of a laminate having layers containing a thermoplastic resin such as polyamide and reinforcing fibers such as glass fibers. Patent Document 4 discloses a laminate having a fibrous layer containing resin and fibers, and a heat insulating layer containing resin and an inorganic filler. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2001-294048 [Patent Document 2] Japanese Patent Publication No. 2013-97883 [Patent Document 3] International Publication No. 2019 / 044801 [Patent Document 4] International Publication No. 2022-071087 [Overview of the project] [Problems that the invention aims to solve]

[0005] Various types of batteries, such as lithium-ion batteries, are susceptible to thermal runaway and ignition due to defects such as internal short circuits. Automotive batteries, in particular, are at risk of thermal runaway and ignition due to impacts such as accidents. However, covers made of metal materials, as described in Patent Documents 1 and 2, cannot adequately suppress heat transfer caused by battery ignition, and thus cannot prevent the interior of the vehicle from rapidly becoming hot. Furthermore, even the automotive battery housing described in Patent Document 3 has the problem of not adequately suppressing the combustion of the resin itself. Additionally, while the material described in Patent Document 4 exhibits sufficient flame-retardant performance against battery thermal runaway, it faces challenges in weight reduction. Therefore, there is a need for a material that can exhibit even higher flame-retardant performance.

[0006] The present invention aims to provide a laminate that has sufficient moldability, excellent lightweight properties, and can exhibit high flame-retardant performance. [Means for solving the problem]

[0007] (1) The present disclosure is a laminate comprising a flame-shielding layer containing a first inorganic fiber having a melting point of 1000°C or higher and a resin A, and a fiber layer containing fibers on at least one surface of the flame-shielding layer. Disclosure (2) is a laminate of Disclosure (1), wherein the fiber layer further comprises resin B. Disclosure (3) is a laminate of Disclosure (1) or (2), wherein the first inorganic fiber is a nonwoven or woven fabric. Disclosure (4) is a laminate of Disclosure (1), (2), or (3), wherein the first inorganic fiber is at least one selected from the group consisting of silica fibers and alumina fibers. Disclosure (5) is a laminate of Disclosure (2), wherein the oxygen index of resin A and resin B is 20 or higher. The present disclosure (6) is a laminate of the present disclosure (1), (2), (3), (4), or (5), wherein the resin A is a chlorinated vinyl chloride resin having an average degree of polymerization of 400 to 3000 and a chlorine content of 57 to 72% by mass. The present disclosure (7) is a laminate of the present disclosure (2) or (5), wherein the resin B is a chlorinated vinyl chloride resin having an average degree of polymerization of 400 to 3000 and a chlorine content of 57 to 72% by mass. The present disclosure (8) is a laminate of the present disclosure (1), (2), (3), (4), (5), (6), or (7), wherein the fiber layer contains a second inorganic fiber. The present disclosure (9) is a laminate of the present disclosure (8), wherein the second inorganic fiber is at least one selected from the group consisting of glass fiber and carbon fiber. The present disclosure (10) is a laminate of the present disclosure (1), (2), (3), (4), (5), (6), (7), (8), or (9), which further has a resin layer containing resin C between the fiber layer and the flame-retardant layer. The present disclosure (11) is a laminate of the present disclosure (10), wherein the oxygen index of the resin C is 20 or more. The present disclosure (12) is a laminate of the present disclosure (10) or (11), wherein the resin C is a chlorinated vinyl chloride resin having an average degree of polymerization of 400 to 3000 and a chlorine content of 57 to 72% by mass. Hereinafter, the present invention will be described in detail.

[0008] As a result of intensive studies, the inventors have found that a laminate having a flame-retardant layer containing a first inorganic fiber having a melting point of 1000°C or higher and resin A and a fiber layer containing fibers exhibits extremely excellent flame-retardant performance and can maintain high flame-retardant performance against extremely high-temperature flames generated by the ignition of cells. Furthermore, it has been found that such a laminate has sufficient formability and is also excellent in light weight, leading to the completion of the present invention. Note that the flame-retardant performance means the performance of blocking flames, such as preventing the transmission of flames to adjacent battery cells when a battery cell catches fire.

[0009] (Flame-retardant layer) The laminate has a flame-retardant layer containing a first inorganic fiber having a melting point of 1000 °C or higher and resin A. By having the flame-retardant layer, the resin is physically constrained between the fibers, so that the resin is difficult to flow at high temperatures, and a flame-retardant layer with a certain thickness can be formed. In addition, the first inorganic fiber itself has mechanical strength and is difficult to soften and melt even at high temperatures, so the pressure resistance against the increase in internal pressure during cell abnormalities and the blast resistance against the ejection of high-temperature particles can be enhanced compared to forming a flame-retardant layer only with resin. As a result, a laminate excellent in flame-retardant performance can be obtained.

[0010] The flame-retardant layer contains an inorganic fiber having a melting point of 1000 °C or higher. Thereby, when used as a cover for an in-vehicle battery, it is possible to make it difficult for the flame generated inside the battery to be transmitted to the outside. The melting point of the inorganic fiber is preferably 1000 °C or higher, more preferably 1200 °C or higher, and still more preferably 1600 °C or higher.

[0011] Examples of the inorganic fiber having a melting point of 1000 °C or higher include ceramic fibers such as silica fiber, alumina fiber, silica-alumina fiber, alumina silicate fiber, zirconia fiber, alkaline earth silicate fiber, potassium titanate fiber, etc., and metal fibers such as iron, gold, copper, brass, stainless steel, etc. Among them, from the viewpoint of moldability, silica fiber and alumina fiber are preferable. Further, among silica fibers, those which are high-silica glass having 95% by mass or more of silicon dioxide are preferable, and among alumina fibers, those having 70% by mass or more of aluminum oxide are preferable.

[0012] The average fiber diameter of the first inorganic fiber is preferably 2 μm or more, more preferably 3 μm or more, preferably 30 μm or less, and more preferably 26 μm or less.

[0013] The first inorganic fiber may be discontinuous fibers in which the fibers are intermittently divided, or may be continuous fibers that are not divided. If the first inorganic fiber is a discontinuous fiber, the average fiber length of the first inorganic fiber is preferably 2 mm or more, more preferably 4 mm or more, preferably 100 mm or less, and more preferably 80 mm or less.

[0014] The specific gravity of the first inorganic fiber described above is preferably 1.5 or higher, more preferably 1.7 or higher, even more preferably 2.0 or higher, preferably 3.0 or lower, more preferably 2.7 or lower, and even more preferably 2.6 or lower. The above specific gravity can be measured using, for example, an electronic hydrometer.

[0015] The form of the first inorganic fiber described above is not particularly limited, but examples include fibrous material, woven fabric, nonwoven fabric sheet, etc. Among these, nonwoven fabric and woven fabric are preferred from the viewpoint of blast resistance due to ejection of high-temperature particles.

[0016] If the first inorganic fiber described above is in sheet form, the basis weight of the fiber is 15 g / m². 2 Preferably, it should be 350 g / m² or more. 2 It is more preferable that it be greater than or equal to 1000 g / m². 2 Preferably, it is 650 g / m². 2 The following is more preferable:

[0017] When the first inorganic fiber described above is in sheet form, the number of layers of the fiber is preferably 3 or more, more preferably 5 or more, preferably 15 or fewer, and more preferably 10 or fewer, from the viewpoint of ensuring strength.

[0018] The content of the first inorganic fiber in the flame-retardant layer is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less. When the content of the first inorganic fiber described above is within the above range, the moldability of the laminate can be sufficiently improved.

[0019] The content of the first inorganic fiber in the flame-shielding layer is preferably 25 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 35 parts by mass or more, preferably 150 parts by mass or less, more preferably 120 parts by mass or less, and even more preferably 100 parts by mass or less, per 100 parts by mass of the resin.

[0020] The content of the first inorganic fiber in the laminate is preferably 1% by mass or more, more preferably 5% by mass or more, preferably 50% by mass or less, and more preferably 45% by mass or less.

[0021] The above flame-retardant layer contains resin A. Examples of resin A include synthetic resins such as thermoplastic resins and thermosetting resins, and elastomers.

[0022] Examples of the thermoplastic resins mentioned above include halogen-containing resins such as chlorinated polyvinyl chloride resin (CPVC) and polyvinyl chloride resin (PVC), polyolefins such as polyethylene and polypropylene, polystyrene (PS), acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylic resins such as polymethyl methacrylate, polyamide, polycarbonate, polysulfone (PSU resin), polyphenylsulfone (PPSU), polyethersulfone (PES resin), polyetherimide (PEI resin), polyphenylene sulfide (PPS resin), polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyimide, polyphenylene ether, polyetherether ketone, and liquid crystal polymers. Among these, halogen-containing resins, polycarbonate, and polyamide are preferred, chlorinated polyvinyl chloride resin and vinyl chloride resin are more preferred, and chlorinated polyvinyl chloride resin is even more preferred.

[0023] Examples of the thermosetting resins mentioned above include polyurethane, phenolic resin, epoxy resin, urea resin, melamine resin, silicone resin, unsaturated polyester resin, alkyd resin, and thermosetting polyimide.

[0024] Examples of the above-mentioned elastomers include thermoplastic elastomers such as olefin-based elastomers, styrene-based elastomers, ester-based elastomers, amide-based elastomers, and vinyl chloride-based elastomers.

[0025] The above resin A may be used alone or in combination of two or more types. Among these, thermoplastic resins are preferred. Furthermore, chlorinated polyvinyl chloride resins and polyvinyl chloride resins are more preferred because the decomposition gases generated by the resin at high temperatures block the supply of oxygen from the outside, and further carbonize the resin to improve its flame-retardant properties. Furthermore, the above resin may be subjected to crosslinking or modification, to the extent that it does not impede the effects of the present invention. The crosslinking method is not particularly limited and can be any crosslinking method commonly used for the above-mentioned resin components, such as a crosslinking method using various crosslinking agents, peroxides, etc., or a crosslinking method using electron beam irradiation.

[0026] The resin A described above preferably has a heating weight loss of 30% by mass or more at 400°C, and more preferably 80% by mass or less. When the heat loss rate is within the above range, it is possible to sufficiently suppress the loss of strength while suppressing the disappearance of resin due to heat. The above-mentioned heat loss rate is more preferably 50% by mass or more, and more preferably 75% by mass or less. The above-mentioned heat loss rate can be measured, for example, by a thermogravimetric (TG) device.

[0027] Furthermore, the time required for the resin A to reach a heating weight loss of 50% by mass at 400°C is preferably 10 seconds or more, more preferably 30 seconds or more, preferably 20 minutes or less, and more preferably 15 minutes or less. The time required for the above-mentioned heat loss rate to reach 50% by mass can be determined, for example, by a thermogravimetric (TG) device.

[0028] The oxygen index of the above resin A is preferably 20 or higher. When the oxygen index is 20 or higher, it can exhibit excellent flame-retardant properties. The oxygen index is more preferably 22 or higher, more preferably 90 or lower, and more preferably 70 or lower. The above oxygen index represents the minimum oxygen concentration (volume %) required for the material to sustain combustion, and can be measured, for example, by methods conforming to JIS K7201-2:2007 or ASTM D2863.

[0029] The weight-average molecular weight (Mw) of resin A is preferably 1,000 to 1,000,000, and more preferably 50,000 to 200,000. Furthermore, with respect to thermosetting resins, it is preferable that they are crosslinked to the extent that they do not flow when heated, but the degree of crosslinking is not limited to the above extent.

[0030] The number-average molecular weight (Mn) of resin A is preferably 35,000 or more, and preferably 90,000 or less. The weight-average molecular weight (Mw) and number-average molecular weight (Mn) mentioned above are average molecular weights calculated on a polystyrene basis, and can be obtained by performing GPC measurements using, for example, column LF-804 (manufactured by Showa Denko Corporation). However, for polyamides, it is preferable to use the average molecular weight calculated on a polymethyl methacrylate (PMMA) basis.

[0031] The glass transition temperature of resin A is preferably 0°C or higher, more preferably 20°C or higher, even more preferably 40°C or higher, preferably 300°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower. The above glass transition temperature can be measured, for example, according to JIS K 7121.

[0032] Furthermore, if the resin A contains chlorinated polyvinyl chloride resin, the chlorine content of the chlorinated polyvinyl chloride resin is preferably 57% by mass or more, more preferably 60% by mass or more, preferably 72% by mass or less, and more preferably 71% by mass or less. By setting it within the above range, good heat resistance and moldability can be achieved. The chlorine content mentioned above can be measured, for example, by a method compliant with JIS K 7229.

[0033] The average degree of polymerization of the above-mentioned chlorinated polyvinyl chloride resin is preferably 400 or higher, more preferably 500 or higher, preferably 3000 or lower, and more preferably 2000 or lower. When the average degree of polymerization is within the above range, pyrolysis products are less likely to scatter during combustion, a decrease in strength can be suppressed, and high flame-retardant performance can be maintained. The above average degree of polymerization can be measured, for example, by a method conforming to JIS K 6720-2:1999.

[0034] The above-mentioned chlorinated polyvinyl chloride resin preferably has the constituent units (b) and (c) shown in the following formulas (b) and (c).

[0035] [ka]

[0036] In the above-mentioned chlorinated polyvinyl chloride resin, the ratio of constituent unit (b) to the total constituent units is preferably 5.1 mol% or more, more preferably 15.2 mol% or more, preferably 39.8 mol% or less, and more preferably 30.0 mol% or less. Furthermore, in the above-mentioned chlorinated polyvinyl chloride resin, the ratio of constituent unit (c) to the total constituent units is preferably 5.2 mol% or more, more preferably 25.1 mol% or more, preferably 54.9 mol% or less, and more preferably 40.0 mol% or less.

[0037] The molar ratios of constituent units (b) and (c) of the chlorinated polyvinyl chloride resin described above reflect the sites where chlorine is introduced when polyvinyl chloride resin (PVC) is chlorinated. Before chlorination, PVC has 0 mol% of constituent units (b) and (c), but these increase with chlorination. The molar ratio of constituent units (b) and (c) of the above-mentioned chlorinated polyvinyl chloride resin can be measured by molecular structure analysis using NMR. NMR analysis can be performed in accordance with the method described in RAKomoroski, RG Parker, JP Shocker, Macromolecules, 1985, 18, 1257-1265.

[0038] The chlorinated polyvinyl chloride resin mentioned above is a resin obtained by chlorinating polyvinyl chloride resin (PVC). As the vinyl chloride resin mentioned above, vinyl chloride homopolymers, copolymers of vinyl chloride monomer and a monomer having an unsaturated bond copolymerizable with vinyl chloride monomer, and graft copolymers obtained by graft copolymerizing vinyl chloride monomer into a polymer can be used. These polymers may be used individually or in combination of two or more.

[0039] Examples of monomers having unsaturated bonds that can copolymerize with the vinyl chloride monomer include α-olefins, vinyl esters, vinyl ethers, (meth)acrylic acid esters, aromatic vinyls, vinyl halides, N-substituted maleimides, and one or more of these can be used. Examples of the above-mentioned α-olefins include ethylene, propylene, and butylene. Examples of the vinyl esters mentioned above include vinyl acetate and vinyl propionate. Examples of the vinyl ethers mentioned above include butyl vinyl ether and cetyl vinyl ether. Examples of the above-mentioned (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, butyl acrylate, and phenyl methacrylate. Examples of the aromatic vinyls mentioned above include styrene and α-methylstyrene. Examples of the above-mentioned vinyl halogens include vinylidene chloride and vinylidene fluoride. Examples of the above-mentioned N-substituted maleimides include N-phenylmaleimide and N-cyclohexylmaleimide.

[0040] The polymer used for graft copolymerization of the vinyl chloride monomer is not particularly limited, as long as it is a polymer that graft polymerizes vinyl chloride monomer. Examples include ethylene copolymers, acrylonitrile-butadiene copolymers, polyurethanes, chlorinated polyethylene, and chlorinated polypropylene. These may be used individually or in combination of two or more. Examples of the above-mentioned ethylene copolymers include ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate-carbon monoxide copolymer, ethylene-methyl methacrylate copolymer, and ethylene-propylene copolymer.

[0041] The average degree of polymerization of the above-mentioned PVC is not particularly limited, but is preferably 400 to 3000, and more preferably 600 to 2000, which are commonly used. The average degree of polymerization can be measured by the method described in JIS K 6720-2:1999. The polymerization method for the above-mentioned PVC is not particularly limited, and conventionally known methods such as aqueous suspension polymerization, bulk polymerization, solution polymerization, and emulsion polymerization can be used.

[0042] The content of resin A in the flame-retardant layer is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less.

[0043] The content of resin A constituting the flame-shielding layer in the laminate is preferably 1% by mass or more, more preferably 5% by mass or more, preferably 50% by mass or less, and more preferably 45% by mass or less.

[0044] The flame-retardant layer described above may contain fibers other than the first inorganic fiber described above. Other fibers mentioned above include reinforcing fibers such as inorganic fibers with a melting point of less than 1000°C. Examples of the above-mentioned metal fibers include fibers made from metals such as silver and aluminum. Examples of the inorganic fibers mentioned above include carbon fibers, glass, basalt, silicon carbide, silicon nitride, and other inorganic materials. Examples of the carbon fibers include PAN-based carbon fibers, pitch-based carbon fibers, cellulose-based carbon fibers, and vapor-grown carbon fibers. Examples of the glass fibers include E-glass, C-glass, S-glass, and T-glass. In particular, from the viewpoint of strength after combustion, the other fibers mentioned above are preferably inorganic fibers, and more preferably at least one selected from the group consisting of carbon fibers and glass fibers.

[0045] The average fiber diameter of the other fibers mentioned above is preferably 2 μm or more, more preferably 3 μm or more, preferably 30 μm or less, and more preferably 26 μm or less.

[0046] The other fibers mentioned above may be discontinuous fibers in which the fibers are intermittently broken, or they may be continuous fibers that are not broken. If the other fibers mentioned above are discontinuous fibers, the average fiber length of the other fibers is preferably 2 mm or more, more preferably 4 mm or more, preferably 100 mm or less, and more preferably 80 mm or less.

[0047] The specific gravity of the above-mentioned other fibers is preferably 1.5 or higher, more preferably 1.7 or higher, even more preferably 2.0 or higher, preferably 3.0 or lower, more preferably 2.7 or lower, and even more preferably 2.6 or lower. The above specific gravity can be measured using, for example, an electronic hydrometer.

[0048] The other forms of fibers mentioned above are not particularly limited, but include, for example, fibrous, woven, knitted, and nonwoven sheet-like materials. If the above-mentioned other fibers are in sheet form, the basis weight of the above-mentioned other fibers is 15g / m². 2 Preferably, it should be 350 g / m² or more. 2 It is more preferable that it be greater than or equal to 1000 g / m². 2 Preferably, it is 650 g / m². 2 The following is more preferable:

[0049] The flame-shielding layer may, in addition to the first inorganic fiber and resin A, contain additives such as stabilizers, lubricants, inorganic fillers, pigments, flame retardants, antioxidants, processing aids, ultraviolet absorbers, and light stabilizers, as needed.

[0050] The above-mentioned stabilizers are not particularly limited and include, for example, heat stabilizers and heat stabilization aids. The above-mentioned heat stabilizers are not particularly limited and include, for example, organotin-based heat stabilizers, lead-based heat stabilizers, calcium-zinc-based heat stabilizers, barium-zinc-based heat stabilizers, barium-cadmium-based heat stabilizers, and so on. Examples of the above organotin-based heat stabilizers include dibutyltin mercapto, dioctyltin mercapto, dimethyltin mercapto, dibutyltin mercapto, dibutyltin maleate, dibutyltin maleate polymer, dioctyltin maleate, dioctyltin maleate polymer, dibutyltin laurate, and dibutyltin laurate polymer. Examples of the lead-based heat stabilizers mentioned above include lead stearate, dibasic lead phosphate, and tribasic lead sulfate. These may be used individually or in combination of two or more. The above-mentioned heat stabilization aids are not particularly limited and include, for example, epoxidized soybean oil, phosphate esters, polyols, hydrotalcite, zeolites, etc. These may be used alone or in combination of two or more.

[0051] Examples of the above-mentioned lubricants include internal lubricants and external lubricants. Internal lubricants are used to reduce the flow viscosity of the molten resin during molding and to prevent frictional heat generation. The internal lubricants are not particularly limited and include, for example, butyl stearate, lauryl alcohol, stearyl alcohol, epoxy soybean oil, glycerin monostearate, stearic acid, and bisamide. These may be used alone or in combination of two or more. The above-mentioned external lubricant is used to improve the sliding effect between the molten resin and the metal surface during molding. The external lubricant is not particularly limited and examples include paraffin wax, polyolefin wax, ester wax, and montanic acid wax. These may be used individually or in combination of two or more.

[0052] The inorganic fillers mentioned above are not particularly limited and include, for example, silica, diatomaceous earth, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, ferrites, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, dohnite, hydrotalcite, calcium sulfate, barium sulfate, calcium silicate, talc, clay, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass beads, silica balloon, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon balloon, charcoal powder, various metal powders, potassium titanate, magnesium sulfate, lead zirconia titanate, aluminum borate, molybdenum sulfide, silicon carbide, zinc borate, various magnetic powders, fly ash, dewatered sludge, etc.

[0053] The above-mentioned pigments are not particularly limited and include, for example, organic pigments such as azo, phthalocyanine, slene, and dye lake pigments; and inorganic pigments such as oxide, molybdenum chromate, sulfide / selenium, and ferrocyanide pigments.

[0054] The above-mentioned antioxidants are not particularly limited, and examples include phenolic antioxidants. The above-mentioned light stabilizers are not particularly limited and include, for example, hindered amine-based light stabilizers.

[0055] The above processing aids are not particularly limited and include, for example, acrylic processing aids such as alkyl acrylate-alkyl methacrylate copolymers with a mass-average molecular weight of 100,000 to 2,000,000. The above acrylic processing aids are not particularly limited and include, for example, n-butyl acrylate-methyl methacrylate copolymers and 2-ethylhexyl acrylate-methyl methacrylate-butyl methacrylate copolymers. These may be used alone or in combination of two or more.

[0056] The above-mentioned UV absorbers are not particularly limited and include, for example, salicylate esters, benzophenones, benzotriazoles, cyanoacrylates, and other UV absorbers.

[0057] The thickness of the flame-retardant layer is preferably 0.2 mm or more, more preferably 0.4 mm or more, preferably 10 mm or less, and more preferably 7 mm or less. Furthermore, if the laminate has two or more flame-resistant layers, the thickness of the flame-resistant layers refers to the total thickness of the flame-resistant layers.

[0058] The proportion of the flame-shielding layer in the laminate is preferably 1 / 10 or more by mass, more preferably 2 / 10 or more, preferably 9 / 10 or less, and more preferably 8 / 10 or less.

[0059] The ratio of the thickness of the flame-shielding layer in the laminate is preferably 1 / 10 or more, more preferably 2 / 10 or more, preferably 9 / 10 or less, and more preferably 8 / 10 or less.

[0060] (Fiber layer) The laminate described above has a fiber layer on at least one side of the flame-retardant layer. The presence of the above-mentioned fiber layer allows for sufficient mechanical strength, and for example, when used as a cover for an in-vehicle battery, it can prevent damage in the event of a collision or other accident, and make it difficult for flames generated inside the battery to spread to the outside.

[0061] The above fiber layer contains fibers. Examples of the above-mentioned fibers include reinforcing fibers such as organic fibers and second inorganic fibers. Examples of the above-mentioned organic fibers include fibers made from organic materials such as aramid, polybenzoxazole (PBO), polyphenylene sulfide, polyester, polyamide, and polyethylene. Examples of the second inorganic fiber mentioned above include fibers made from inorganic materials such as metal fibers, carbon fibers, glass, basalt, silicon carbide, and silicon nitride. Examples of the metal fibers mentioned above include fibers made from metals such as iron, gold, silver, copper, aluminum, brass, and stainless steel. Examples of the carbon fibers mentioned above include PAN-based carbon fibers, pitch-based carbon fibers, cellulose-based carbon fibers, and vapor-grown carbon fibers. Examples of the glass fibers mentioned above include E-glass, C-glass, S-glass, and T-glass. In particular, from the viewpoint of strength after combustion, the above fiber is preferably a second inorganic fiber, and more preferably at least one selected from the group consisting of carbon fiber and glass fiber.

[0062] The average fiber diameter of the above fibers is preferably 2 μm or more, more preferably 3 μm or more, preferably 30 μm or less, and more preferably 26 μm or less.

[0063] The above-mentioned fiber may be a discontinuous fiber in which the fiber is intermittently segmented, or may be a continuous fiber that is not segmented. When the above-mentioned fiber is a discontinuous fiber, the average fiber length of the above-mentioned fiber is preferably 2 mm or more, more preferably 4 mm or more, preferably 100 mm or less, and more preferably 80 mm or less.

[0064] The specific gravity of the above-mentioned fiber is preferably 1.5 or more, more preferably 1.7 or more, still more preferably 2.0 or more, preferably 3.0 or less, more preferably 2.7 or less, and still more preferably 2.6 or less. The above-mentioned specific gravity can be measured using, for example, an electronic specific gravity meter or the like.

[0065] Examples of the form of the above-mentioned fiber include fibrous, woven, knitted, non-woven sheet-like, etc. When the above-mentioned fiber is in sheet form, the basis weight of the above-mentioned fiber is preferably 100 g / m 2 or more, more preferably 350 g / m 2 or more, preferably 1000 g / m 2 or less, more preferably 650 g / m 2 or less.

[0066] When the above-mentioned fiber is in sheet form, the number of layers of the above-mentioned fiber is preferably 3 layers or more, more preferably 5 layers or more, preferably 15 layers or less, and more preferably 10 layers or less from the viewpoint of ensuring strength.

[0067] The content of the above-mentioned fiber in the above-mentioned fiber layer is preferably 30% by mass or more, more preferably 40% by mass or more, still more preferably 50% by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less, and still more preferably 60% by mass or less. When the content of the above-mentioned fiber is within the above range, the mechanical strength of the laminate can be sufficiently increased.

[0068] The fiber content in the laminate is preferably 20% by mass or more, more preferably 30% by mass or more, preferably 70% by mass or less, and more preferably 60% by mass or less.

[0069] Relationship between the first inorganic fibers constituting the flame-retardant layer and the fibers constituting the fiber layer (weight ratio, basis weight ratio, fiber diameter ratio, total content in the laminate, etc.)

[0070] The above fiber layer preferably further contains resin B. By including resin B, a lightweight flame-retardant layer with excellent mechanical strength can be created.

[0071] The resin B mentioned above is the same as the resin A that constitutes the flame-shielding layer described above. Among these, chlorinated polyvinyl chloride resin and polyvinyl chloride resin are preferred, and chlorinated polyvinyl chloride resin is more preferred.

[0072] The content of resin B in the fiber layer is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the content of the above-mentioned fibers is within the above range, the mechanical strength of the laminate can be sufficiently increased.

[0073] The content of resin B in the laminate is preferably 20% by mass or more, more preferably 30% by mass or more, preferably 70% by mass or less, and more preferably 60% by mass or less.

[0074] The fiber layer may further contain additives such as heat stabilizers, lubricants, inorganic fillers, pigments, flame retardants, antioxidants, processing aids, ultraviolet absorbers, and light stabilizers, as needed. Examples of the above-mentioned additives include those similar to those that constitute the flame-blocking layer described above.

[0075] The thickness of the fiber layer is preferably 0.2 mm or more, more preferably 0.3 mm or more, preferably 10 mm or less, and more preferably 7 mm or less. Furthermore, if the laminate has two or more fiber layers, the thickness of the fiber layers refers to the sum of the thicknesses of the fiber layers.

[0076] The proportion of the fiber layer in the laminate is preferably 0.2 or more by mass ratio, more preferably 0.5 or more, preferably 0.95 or less, and more preferably 0.9 or less.

[0077] The ratio of the thickness of the fiber layer in the laminate is preferably 0.15 or more, more preferably 0.5 or more, preferably 0.95 or less, and more preferably 0.9 or less.

[0078] The ratio of the thickness of the fiber layer to the thickness of the flame-retardant layer (thickness of the fiber layer / thickness of the flame-retardant layer) is preferably 1 or more, more preferably 2 or more, preferably 25 or less, and more preferably 20 or less.

[0079] The shape of the above-mentioned laminate is not particularly limited and can be film-like, plate-like, sheet-like, cylindrical, annular, frame-like, box-like, etc.

[0080] The laminate described above has a fiber layer on one side of the flame-retardant layer, and may further have a fiber layer on the other side. In other words, the laminate may have a laminated structure of fiber layer / flame-shielding layer / fiber layer. The above fiber layers may have the same configuration or different configurations, but it is preferable that they have the same configuration.

[0081] Furthermore, the laminate may have a three-layer structure of fiber layer / flame-resistant layer / fiber layer, or a three-layer structure of flame-resistant layer / fiber layer / flame-resistant layer, or a laminate structure in which the layers are arranged in order from the flame-resistant layer as flame-resistant layer / fiber layer / flame-resistant layer / ... with the other end being a flame-resistant layer or a fiber layer, or a laminate structure in which the layers are arranged in order from the fiber layer as fiber layer / flame-resistant layer / fiber layer / ... with the other end being a flame-resistant layer or a fiber layer.

[0082] The laminate described above may also have layers made of other components besides the flame-shielding layer and the fiber layer, such as a resin layer containing resin C, a heat insulating material such as glass wool, or an insulating material such as a mica sheet. Furthermore, the laminate may have the fiber layer on at least one side of the flame-shielding layer, and may have a layer made of the other components on the other side of the flame-shielding layer, and it is preferable to have a resin layer containing resin C between the fiber layer and the flame-shielding layer. In particular, it is preferable that the laminate has the fiber layer on one side of the flame-blocking layer and a layer made of other components on the other side of the flame-blocking layer, and that it has a laminated structure of fiber layer / flame-blocking layer / layer made of other components / fiber layer. In that case, it is preferable that the layers are laminated in the order of fiber layer / flame-blocking layer / layer made of other components (=resin layer) / fiber layer from the cell side which is the high-temperature flame source. In particular, if the layer made of other components is a resin layer made of chlorinated polyvinyl chloride resin, when the laminate is heated by a flame at a high temperature of 1000°C or higher, the flame-blocking layer containing inorganic fibers makes it difficult to soften and melt, suppressing fire escape, and furthermore, it can block the supply of oxygen from the outside, so that the resin in the resin layer, which is a layer further from the flame than the flame-blocking layer, forms a carbonized layer and an excellent effect is obtained.

[0083] The resin C constituting the above resin layer may be the same as the resin constituting the above flame-shielding layer and the above fiber layer. Among these, chlorinated polyvinyl chloride resins are preferred.

[0084] The content of resin C in the above resin layer is preferably 50% by mass or more, more preferably 70% by mass or more, preferably 100% by mass or less, and more preferably 99% by mass or less.

[0085] The above resin layer may contain an inorganic filler. As inorganic fillers, those similar to those described above can be used.

[0086] The above resin layer may further contain additives such as heat stabilizers, lubricants, and foaming agents.

[0087] The same heat stabilizers and lubricants as those described above can be used.

[0088] The blowing agent mentioned above may be a chemical blowing agent or a physical blowing agent. Examples of the above-mentioned chemical blowing agents include thermal decomposition type inorganic blowing agents, thermal decomposition type organic blowing agents, inorganic reactive blowing agents using sodium bicarbonate and acid, and organic reactive blowing agents using isocyanate and water. Examples of the above-mentioned thermal decomposition type inorganic blowing agents include thermally expandable graphite, ammonium acid, sodium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, and anhydrous monosodium citrate. Examples of the above-mentioned pyrolysis-type organic blowing agents include azodicarbonamide, azodicarboxylic acid metal salts (such as barium azodicarboxylic acid), azobisisobutyronitrile and other azo compounds, nitroso compounds such as N,N'-dinitrosopentamethylenetetramine, hydrazodicarbonamide, hydrazine derivatives such as 4,4'-oxybis(benzenesulfonyl hydrazide) and toluenesulfonyl hydrazide, and semicarbazide compounds such as toluenesulfonyl semicarbazide. Examples of physical blowing agents include vermiculite and thermally expandable particles containing hydrocarbons.

[0089] The proportion of the resin layer in the laminate is preferably 1 / 20 or more by mass ratio, more preferably 1 / 10 or more, preferably 7 / 10 or less, and more preferably 5 / 10 or less.

[0090] The ratio of the thickness of the resin layer in the laminate is preferably 1 / 20 or more, more preferably 1 / 10 or more, preferably 7 / 10 or less, and more preferably 5 / 10 or less.

[0091] The thickness of the laminate is preferably 0.4 mm or more, more preferably 0.7 mm or more, preferably 20 mm or less, and more preferably 14 mm or less.

[0092] As a method for manufacturing the above-mentioned laminate, for example, a composition containing the first inorganic fibers and resin A that constitute the flame-resistant layer is prepared, and the flame-resistant layer is formed using this composition. Next, sheet-like fibers that will become the fiber layer are prepared. These are laminated by hot press molding or the like to form a structure in which fiber layer / flame-resistant layer / fiber layer is laminated in this order. Alternatively, each layer may be formed in which flame-resistant layer / fiber layer / flame-resistant layer is laminated in this order. Alternatively, a composition in which sheet-like fibers are impregnated with resin B may be prepared as the fiber layer, and the fiber layer may be formed using this composition. Methods for forming the flame-retardant layer and fiber layer mentioned above include, for example, hand lay-up molding, spray-up molding, resin transfer molding, bag molding, injection molding, extrusion molding, and stamping molding. Furthermore, other layers, such as a resin layer, may be formed between the flame-retardant layer and the fiber layer, or as the outermost layer.

[0093] The above laminate has good moldability, is lightweight, and also has excellent flame-retardant properties, making it suitable for use as a component in transport equipment and a component in battery devices.

[0094] Examples of the above-mentioned transport vehicles include automobiles such as gasoline-powered cars, hybrid cars, electric cars, and fuel cell vehicles; motorcycles such as gasoline-powered motorcycles, hybrid motorcycles, and electric motorcycles; bicycles such as electric-assist bicycles; railway vehicles; ships; and aircraft. Furthermore, examples of components for the above-mentioned transport aircraft include mechanical components, interior components, exterior components, window glass, light covers, and the like. Examples of the above-mentioned mechanical components include cooling pipes, airbag covers, air ducts, and heater units. Examples of the above-mentioned interior components include the ceiling, instrument panel, console box, armrest, seat belt buckle, switches, and door trim. Examples of the above-mentioned exterior components include emblems, license plate housings, bumper core materials, and undercovers.

[0095] Examples of the above-mentioned battery devices include primary batteries such as nickel-manganese batteries, lithium batteries, and zinc-air batteries; secondary batteries such as nickel-metal hydride batteries, lithium-ion batteries, and lead-acid batteries; solar cells such as silicon-based solar cells, dye-sensitized solar cells, and perovskite solar cells; and fuel cells such as polymer electrolyte fuel cells, alkaline fuel cells, phosphoric acid fuel cells, and solid oxide fuel cells. Examples of components for the above-mentioned battery device include a battery cover, a water jacket for battery cooling, a hydrogen tank cover, a connector, and an insulating sheet. Furthermore, examples of battery device components used in transport aircraft include covers for transport aircraft batteries and covers for vehicle batteries. In particular, the laminate of the present invention can be suitably used as a cover for lithium-ion batteries, and furthermore, even when a battery experiences thermal runaway due to an external impact such as a collision, it can suppress the transmission of flames and heat generated from ignition inside the battery to the outside, making it suitably usable as a cover for automotive batteries. [Effects of the Invention]

[0096] According to the present invention, it is possible to provide a laminate that has sufficient moldability, excellent lightweight properties, and can also exhibit high flame-retardant performance. [Modes for carrying out the invention]

[0097] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples.

[0098] (Example 1) (Preparation of the fiber layer (A)) Resin B (100 parts by mass) was mixed with stabilizer AT-1000 (manufactured by Nitto Kasei Co., Ltd.) and a resin sheet was produced using a calendering machine. Resin B used was chlorinated polyvinyl chloride resin HA-05K (manufactured by Tokuyama Sekisui Kogyo Co., Ltd., chlorine content 67% by mass, average degree of polymerization 500). The chlorine content of the resin was measured according to the method compliant with JIS K 7229, and the average degree of polymerization of the resin was measured according to the method compliant with JIS K 6720-2:1999. Next, as the second inorganic fiber, a sheet-like glass fiber (Nitto Boseki Co., Ltd.'s "MC450A," average fiber diameter 7 μm, average fiber length 50 nm, specific gravity 2.6, basis weight 450 g / m²) is used. 2 Using this material, a resin sheet was placed on top and melt-impregnated using a press to obtain a fiber layer (A). Calculations based on the mass ratio before and after impregnation showed that the fiber layer (A) contained 60% by mass of fibers and 40% by mass of resin. The average fiber diameter of the glass fibers was calculated from the average of the fiber diameters of 10 arbitrary points obtained from images taken using a scanning electron microscope (SEM). The average fiber length was calculated from the average of the measurements of 20 arbitrary samples using calipers. Specific gravity was calculated using an electronic hydrometer (Mirage ED120T). Furthermore, the basis weight of the glass fibers was measured by cutting a sheet of glass fiber into 10cm x 10cm sections and measuring the weight per meter. 2 The weight per unit (g) was calculated to determine the value.

[0099] (Preparation of resin layer (B)) 100 parts by mass of resin C was mixed with 10 parts by mass of stabilizer AT-1000 (manufactured by Nitto Kasei Co., Ltd.), and a resin sheet was produced using a calendering machine. For resin C, chlorinated polyvinyl chloride resin HA-05K (manufactured by Tokuyama Sekisui Kogyo Co., Ltd., chlorine content 67% by mass, average degree of polymerization 500) was used. The obtained resin sheets were stacked and melt-impregnated using a press to obtain resin layer (B).

[0100] (Preparation of the flame-resistant layer (C)) 100 parts by mass of resin A was mixed with 10 parts by mass of stabilizer AT-1000 (manufactured by Nitto Kasei Co., Ltd.), and a resin sheet was produced using a calendering machine. As resin A, chlorinated polyvinyl chloride resin HA-05K (manufactured by Tokuyama Sekisui Kogyo Co., Ltd., chlorine content 67% by mass, average degree of polymerization 500) was used. Next, as the first inorganic fiber, silica fiber woven fabric (NICHIAS Corporation's "Siltex Cloth 1000M", thickness 0.65 mm, basis weight 625 g / m²) is used. 2 Using a material with a melting point of 1600°C, a flame-resistant layer (C) was obtained by layering it with a resin sheet and melt-impregnating it using a press. Calculations based on the mass ratio before and after impregnation showed that the fiber content in the flame-resistant layer (C) was 58% by mass and the resin content was 42% by mass. The basis weight of the silica fiber was determined by cutting a 10cm x 10cm piece of silica fiber fabric and measuring its weight per meter. 2 The weight per unit (g) was calculated to determine the value.

[0101] (Preparation of the fiber layer (D)) In the preparation of the fiber layer (A), the fiber layer (D) was obtained by adjusting the fiber content to 50% by mass and the resin content to 50% by mass.

[0102] (Fabrication of laminates) The above fiber layer (A), resin layer (B), flame-retardant layer (C), and fiber layer (D) were stacked and pressed in a press machine to obtain a laminate with a thickness of 1.8 mm.

[0103] (Example 2) In the preparation of the flame-retardant layer (C), alumina fiber nonwoven fabric (Isolite Industries Co., Ltd. "1600 Paper 72", thickness 0.5 mm, basis weight 65 g / m²) was used as the first inorganic fiber. 2 A flame-retardant layer (C) was obtained in the same manner as in Example 1, except that a maximum operating temperature of 1600°C was used and the fiber content was adjusted to 22% by mass and the resin content to 78% by mass.

[0104] A laminate with a thickness of 2.0 mm was obtained in the same manner as in Example 1, except that the obtained flame-retardant layer (C) was used and the same material as the fiber layer (A) was used as the fiber layer (D).

[0105] (Example 3) In the preparation of the flame-retardant layer (C), the first inorganic fiber is alumina fiber nonwoven fabric (Isolite Industries Co., Ltd. "1600 Paper 72", thickness 1.0 mm, basis weight 130 g / m²). 2 A flame-retardant layer (C) was obtained in the same manner as in Example 1, except that a maximum operating temperature of 1600°C was used and the fiber content was adjusted to 30% by mass and the resin content to 70% by mass.

[0106] A laminate with a thickness of 2.0 mm was obtained in the same manner as in Example 2, except that the obtained flame-retardant layer (C) was used.

[0107] (Comparative Example 1) Without creating a flame-retardant layer (C), a laminate with a thickness of 2.0 mm was obtained by stacking a fiber layer (A) - resin layer (B) - fiber layer (D) and pressing them with a press machine.

[0108] (Comparative Example 2) In the preparation of the flame-resistant layer (C), instead of silica fiber woven fabric, sheet-like glass fibers (Nitto Boseki Co., Ltd.'s "MC450A", average fiber diameter 7 μm, average fiber length 50 nm, specific gravity 2.6, basis weight 450 g / m²) were used. 2 Using a material with a softening point of 844°C, the fiber content was adjusted to 60% by mass and the resin content to 40% by mass to obtain a flame-retardant layer (C).

[0109] A laminate with a thickness of 3.0 mm was obtained in the same manner as in Example 2, except that the obtained flame-retardant layer (C) was used. (Comparative Example 3) In the preparation of the flame-resistant layer (C), instead of silica fiber woven fabric, sheet-like glass fibers (Nitto Boseki Co., Ltd.'s "MC450A", average fiber diameter 7 μm, average fiber length 50 nm, specific gravity 2.6, basis weight 450 g / m²) were used. 2 Using a material with a softening point of 844°C, the fiber content was adjusted to 60% by mass and the resin content to 40% by mass to obtain a flame-retardant layer (C).

[0110] A laminate with a thickness of 2.1 mm was obtained in the same manner as in Example 2, except that the obtained flame-retardant layer (C) was used.

[0111] (evaluation) The laminates obtained in the examples and comparative examples were evaluated as follows. The results are shown in Table 1.

[0112] (1)Flame retardant The resulting laminate was cut into 100mm x 100mm sections to prepare measurement samples. The sample was fixed to a jig so that the thickness method was vertical, and an acetylene burner (burner tip diameter: processed #50, hole diameter 0.7mm) was irradiated from above, with a distance of 70mm from the outer flame of the burner flame and an outer flame temperature of 1200°C. The time from the start of irradiation until the fire escaped was confirmed was measured and evaluated according to the following criteria. ◎: Time required for the fire to dissipate is 35 seconds or more. ○: Time required for the fire to extinguish is 25 seconds or more but less than 35 seconds. ×: Time required for the fire to dissipate is less than 25 seconds.

[0113] (2) Lightweight The resulting laminate was cut into 10cm x 10cm pieces, and its weight was measured to determine the surface density (kg / m³). 2 The following criteria were used to calculate and evaluate the following: ◎: Surface density is 4.0 kg / m² 2 less than ○: Surface density is 4.0 kg / m³ 2 More than 5.0kg / m 2 less than ×: Surface density is 5.0 kg / m 2 That's all.

[0114] (3) Formability The resulting laminate was examined using an electron microscope to confirm the cross-sectional state of each layer and evaluated according to the following criteria. ◎: No insufficient resin impregnation of the fibers was observed, and no unevenness in impregnation was observed. ○: No insufficient resin impregnation of the fibers was observed. ×: Insufficient resin impregnation of the fibers was confirmed.

[0115] (4) Overall evaluation Based on the results for (1) flame resistance, (2) lightweight properties, and (3) moldability, an overall evaluation was conducted as follows. ○: (1) Flame resistance, (2) Lightweight, (3) Moldability - all of these are "○" or higher. ×: Other than the above

[0116] [Table 1] [Industrial applicability]

[0117] According to the present invention, it is possible to provide a laminate that has sufficient moldability, excellent lightweight properties, and can also exhibit high flame-retardant performance.

Claims

1. A flame-shielding layer comprising a first inorganic fiber and resin A having a melting point of 1000°C or higher, A laminate having a fiber layer containing fibers on at least one surface of the flame-retardant layer.

2. The laminate according to claim 1, wherein the fiber layer further comprises resin B.

3. The laminate according to claim 1 or 2, wherein the first inorganic fiber is a nonwoven fabric or a woven fabric.

4. The laminate according to claim 1 or 2, wherein the first inorganic fiber is at least one selected from the group consisting of silica fibers and alumina fibers.

5. The laminate according to claim 2, wherein the oxygen index of resin A and resin B is 20 or higher.

6. The laminate according to claim 1 or 2, wherein the resin A is a chlorinated polyvinyl chloride resin having an average degree of polymerization of 400 to 3000 and a chlorine content of 57 to 72% by mass.

7. The laminate according to claim 2, wherein the resin B is a chlorinated polyvinyl chloride resin having an average degree of polymerization of 400 to 3000 and a chlorine content of 57 to 72% by mass.

8. The laminate according to claim 1 or 2, wherein the fiber layer includes a second inorganic fiber.

9. The laminate according to claim 8, wherein the second inorganic fiber is at least one selected from the group consisting of glass fibers and carbon fibers.

10. The laminate according to claim 1 or 2, further comprising a resin layer containing resin C between the fiber layer and the flame-retardant layer.

11. The laminate according to claim 10, wherein the oxygen index of the resin C is 20 or higher.

12. The laminate according to claim 10, wherein the resin C is a chlorinated polyvinyl chloride resin having an average degree of polymerization of 400 to 3000 and a chlorine content of 57 to 72% by mass.

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