Laminate, battery case for non-aqueous electrolyte secondary battery, and battery for non-aqueous electrolyte secondary battery

Abstract

Provided are: a laminate comprising a flame-retardant layer and a fiber-reinforced resin layer, wherein the flame-retardant layer contains, on the basis of the total mass of the flame-retardant layer, 20-80 mass% of a thermoplastic resin and 20-80 mass% of at least one flame retardant selected from the group consisting of a phosphorus-based flame retardant, a bromine-based flame retardant, and an inorganic hydrate-based flame retardant, the content of a reinforcing fiber is 0-20 mass% on the basis of the total mass of the flame-retardant layer, and the fiber-reinforced resin layer contains, on the basis of the total mass of the fiber-reinforced resin layer, 30-90 mass% of the thermoplastic resin and 10-70 mass% of the reinforcing fiber; a battery case for a non-aqueous electrolyte secondary battery; and a non-aqueous electrolyte secondary battery comprising same.

Description

[Technical Field]

[0001] The present invention relates to a laminate, a battery case for a non-aqueous electrolyte secondary battery, and a battery for a non-aqueous electrolyte secondary battery. [Background technology]

[0002] Lighter vehicles are more important than ever before in order to reduce CO2 emissions while driving and increase the driving range of electric vehicles, etc. From the perspective of further weight reduction, it is conceivable to reduce the amount of metal used in battery packs and battery modules, or to use resin as the material. On the other hand, there is a demand for ever-improved safety in electric vehicles. For example, various types of batteries, such as lithium batteries, can catch fire due to internal short circuits, overcharging, penetration by external foreign objects, external overheating, abnormal heat generation, etc.

[0003] Patent Document 1, for example, discloses a vehicle battery case made of a carbon fiber-reinforced polypropylene resin that combines flame retardancy, electromagnetic wave shielding properties, and excellent mechanical properties. The vehicle battery case is formed by molding a carbon fiber-reinforced polypropylene resin composition that is obtained by blending 8 to 70 parts by weight of carbon fiber (B) and 0.6 to 37.5 parts by weight of a flame retardant (C) with 100 parts by weight of polypropylene resin (A), and the weight-average fiber length of the carbon fibers in the molded product is 0.5 mm or more and less than 3 mm. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-62189 Summary of the Invention [Problem to be solved by the invention]

[0005] According to the inventors' investigations, it was found that adding a flame retardant to a fiber-reinforced material (fiber-reinforced resin) suppresses the improvement in flame retardancy compared to adding a flame retardant to a resin that is not fiber-reinforced, making it difficult to obtain sufficient flame retardancy. Furthermore, although the battery case described in Patent Document 1 improved the flame retardancy of a vehicle battery case, the flame retardancy was not sufficient, and further improvement in flame retardancy is desired.

[0006] An object of one embodiment of the present invention is to provide a laminate that contains reinforcing fibers but has excellent flame retardancy, a battery case for a non-aqueous electrolyte secondary battery, and a battery for a non-aqueous electrolyte secondary battery including the same. [Means for solving the problem]

[0007] The means for solving the above problems include the following aspects. <1> A flame-retardant layer and a fiber-reinforced resin layer are provided. the flame-retardant layer contains a thermoplastic resin in an amount of 20% by mass to 80% by mass, based on the total mass of the flame-retardant layer, and at least one flame retardant selected from the group consisting of a phosphorus-based flame retardant, a bromine-based flame retardant, and an inorganic hydrate-based flame retardant, in an amount of 20% by mass to 80% by mass, based on the total mass of the flame-retardant layer, and the content of reinforcing fibers is 0% by mass to 20% by mass, based on the total mass of the flame-retardant layer; The fiber reinforced resin layer is a laminate containing 30% by mass to 90% by mass of a thermoplastic resin relative to the total mass of the fiber reinforced resin layer, and 10% by mass to 70% by mass of reinforcing fibers relative to the total mass of the fiber reinforced resin layer. <2> The content of reinforcing fibers contained in the fiber-reinforced resin layer is 10% by mass or more greater than the content of reinforcing fibers contained in the flame-retardant layer. <1> The laminate according to claim 1. <3> The content of at least one flame retardant selected from the group consisting of phosphorus-based flame retardants, bromine-based flame retardants, and inorganic hydrate-based flame retardants in the fiber-reinforced resin layer is 0% by mass or more and less than 20% by mass with respect to the total mass of the fiber-reinforced resin layer, <1> or <2> The laminate according to claim 1. <4> the flame-retardant layer contains the flame retardant in an amount of 40% by mass to 80% by mass relative to the total mass of the flame-retardant layer, The fiber reinforced resin layer contains the reinforcing fibers in an amount of 40% by mass to 60% by mass relative to the total mass of the fiber reinforced resin layer, and the content of at least one flame retardant selected from the group consisting of phosphorus-based flame retardants, bromine-based flame retardants, and inorganic hydrate-based flame retardants is 0% by mass to 10% by mass relative to the total mass of the fiber reinforced resin layer. <1> ~ <3> 10. The laminate according to claim 9, wherein the first and second layers are laminates. <5> The fiber reinforced resin layer contains, as the thermoplastic resin, at least one resin selected from the group consisting of polypropylene resin and polyamide resin, <1> ~ <4> 10. The laminate according to claim 9, wherein the first and second layers are laminates. <6> The reinforcing fibers include at least one fiber selected from the group consisting of carbon fibers and glass fibers. <1> ~ <5> 10. The laminate according to claim 9, wherein the first and second layers are laminates. <7> At least one of the fiber reinforced resin layer and the flame retardant layer contains an electromagnetic wave shielding filler. <1> ~ <6> 10. The laminate according to claim 9, wherein the first and second layers are laminates. <8> The thickness of the fiber reinforced resin layer is 0.5 to 30 mm. <1> ~ <7> 10. The laminate according to claim 9, wherein the first and second layers are laminates. <9> <1> ~ <8> 2. A battery case for a non-aqueous electrolyte secondary battery, comprising the laminate according to any one of 1 to 11. <10> The flame-retardant layer of the laminate is disposed on the inside of the battery case. <9> The battery case for the non-aqueous electrolyte secondary battery according to claim 1. <11> The flame-retardant layers of the laminate are disposed on the inside and outside of the battery case. <9> The battery case for the non-aqueous electrolyte secondary battery according to claim 1. <12> Further comprising an electromagnetic wave shielding layer. <9> ~ <11> 1. A battery case for a non-aqueous electrolyte secondary battery according to any one of the above. <13> <9> ~ <12> 10. A battery for a non-aqueous electrolyte secondary battery, comprising the battery case for a non-aqueous electrolyte secondary battery according to any one of the above items. [Effects of the Invention]

[0008] According to one embodiment of the present invention, there are provided a laminate that contains reinforcing fibers but has excellent flame retardancy, a battery case for a non-aqueous electrolyte secondary battery, and a battery for a non-aqueous electrolyte secondary battery including the same. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in detail below. The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, the term "polymer" is a concept that includes homopolymers and copolymers. In this specification, the use of "to" to indicate a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. In this specification, when a numerical range is indicated by "to", the units written before or after the range indicate the same units unless otherwise specified. As used herein, a combination of two or more preferred embodiments is a more preferred embodiment. In this specification, when a layer contains a plurality of substances corresponding to each component, the amount of each component in each layer means the total amount of the plurality of substances present in the layer, unless otherwise specified. The present invention will be described in detail below.

[0010] (Laminate) The laminate according to the present invention comprises a flame-retardant layer and a fiber-reinforced resin layer, wherein the flame-retardant layer contains a thermoplastic resin in an amount of 20% by mass to 80% by mass, based on the total mass of the flame-retardant layer, and at least one flame retardant selected from the group consisting of phosphorus-based flame retardants, bromine-based flame retardants, and inorganic hydrate-based flame retardants in an amount of 20% by mass to 80% by mass, based on the total mass of the flame-retardant layer, and the reinforcing fiber content is 0% by mass to 20% by mass, based on the total mass of the flame-retardant layer, and the fiber-reinforced resin layer contains a thermoplastic resin in an amount of 30% by mass to 90% by mass, based on the total mass of the fiber-reinforced resin layer, and reinforcing fibers in an amount of 10% by mass to 70% by mass, based on the total mass of the fiber-reinforced resin layer. The laminate according to the present invention has the above-described structure, and therefore has excellent flame retardancy and impact strength despite containing reinforcing fibers. The reason for this is not clear, but is presumed to be as follows. When a flame retardant is added to a resin containing reinforcing fibers (i.e., fiber-reinforced resin), the flame retardancy is less pronounced than when the resin does not contain reinforcing fibers because heat is transferred through the reinforcing fibers when the thermoplastic resin melts (the candle effect). Furthermore, adding a large amount of flame retardant to a fiber-reinforced resin to improve flame retardancy raises concerns about a decline in the mechanical properties (impact strength) of the resulting molded product. In the laminate according to the present invention, it is estimated that the flame retardancy can be further improved by adjusting the content of the reinforcing fibers in the flame retardant layer to 0 to 20 mass %, and that the inclusion of a fiber-reinforced resin layer containing a thermoplastic resin and reinforcing fibers ensures high mechanical properties, resulting in the laminate having excellent flame retardancy despite containing reinforcing fibers.Furthermore, it is estimated that the laminate according to the present invention has excellent flame retardancy and mechanical properties because it includes a flame retardant layer and a fiber-reinforced resin layer having the above-mentioned configurations. The components of the laminate will be described in detail below.

[0011] <Flame-retardant layer> The laminate according to the present invention includes a flame-retardant layer. The flame-retardant layer is a layer containing a thermoplastic resin and a flame retardant. The flame-retardant layer contains at least one flame retardant selected from the group consisting of phosphorus-based flame retardants, bromine-based flame retardants, and inorganic hydrate-based flame retardants. From the viewpoint of further improving the flame retardancy of the laminate, phosphorus-based flame retardants and bromine-based flame retardants are preferred, and phosphorus-based flame retardants are more preferred.

[0012] <<Phosphorus-based flame retardants>> The phosphorus-based flame retardant is not particularly limited as long as it contains a phosphorus atom in its structural formula. When the phosphorus-based flame retardant is a salt, it is sufficient that the structural formula of at least one of the anion component and the cation component contains a phosphorus atom.

[0013] Examples of phosphorus-based flame retardants include phosphate ester compounds, phosphazene compounds, polyphosphate compounds, phosphate compounds, phosphinates, phosphonic acid compounds, phosphine oxide compounds, phosphite compounds, phosphonite compounds, phosphinite compounds, phosphine compounds, phosphaphenanthrene compounds, red phosphorus, etc. Among these, polyphosphate compounds, phosphinates, and red phosphorus are preferred, and polyphosphate compounds are particularly preferred.

[0014] Examples of polyphosphate compounds include ammonium polyphosphate, melamine polyphosphate, melamine-melam-melem polyphosphate, and ammonium polyphosphate. The phosphorus-based flame retardant may be used alone or in combination of two or more kinds.

[0015] The decomposition temperature of the phosphorus-based flame retardant is preferably within the range of 100°C to 500°C, more preferably within the range of 200°C to 470°C, and even more preferably within the range of 250°C to 450°C. The decomposition temperature is measured by measuring the mass of a sample in a thermogravimetric analyzer (TGA) while increasing the temperature at a constant rate (for example, 10°C per minute) up to 700°C, and reading the mass (Td5) at which the sample mass has decreased by 5% by weight from the initial mass. This 5% weight loss temperature (Td5) is then determined as the decomposition temperature.

[0016] Although it is not clear why the flame retardancy improves when the flame retardant layer contains a phosphorus-based flame retardant as a flame retardant, the inventors speculate that this is because the char layer formed by the thermal decomposition of the phosphorus-based flame retardant blocks heat from reaching the fiber-reinforced layer, preventing the candle effect of the reinforcing fiber.

[0017] <<Brominated flame retardants>> As the bromine-based flame retardant, a bromine-containing organic compound is preferred, and examples thereof include ethylene bis(pentabromobiphenyl), hexabromobenzene, tetrabromobisphenol S, hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBA), TBBA epoxy oligomer or polymer, TBBA-bis(2,3-dibromopropyl ether), dibromoethyl-dibromocyclohexane, dibromoneopentyl glycol, tribromophenol, tribromophenol allyl ether, pentabromophenol, pentabromotoluene, hexabromodiphenyl ether, dibromoneopentyl glycol tetracarbonate, and N-methylhexabromophenylamine. Of these, ethylenebis(pentabromobiphenyl) is preferred. The brominated flame retardants may be used alone or in combination of two or more.

[0018] <<Inorganic hydrate flame retardants>> Examples of inorganic hydrate flame retardants include magnesium hydroxide, aluminum hydroxide, alumina (hydrate), zinc borate, hydrotalcite, dawsonite, calcium aluminate, kaolin clay, etc. Among these, magnesium hydroxide and aluminum hydroxide are preferred as inorganic hydrate flame retardants in that they can achieve both flame retardancy and cost efficiency. The inorganic hydrate flame retardants may be used alone or in combination of two or more.

[0019] From the viewpoint of improving flame retardancy, the flame retardant layer may contain a flame retardant other than the phosphorus-based flame retardant, bromine-based flame retardant, and inorganic hydrate-based flame retardant (hereinafter also referred to as "other flame retardant"). Other flame retardants include metal oxides such as zinc oxide, calcium oxide, barium oxide, aluminum oxide, tin oxide, and magnesium oxide; antimony compounds such as antimony trioxide, antimony tetroxide, antimony pentoxide, and sodium antimonate; zinc compounds such as zinc stannate and zinc phosphate; silicone-based flame retardants; and sulfur-based flame retardants.

[0020] The flame-retardant layer contains at least one flame retardant selected from the group consisting of phosphorus-based flame retardants, bromine-based flame retardants, and inorganic hydrate-based flame retardants in an amount of 20% by mass to 80% by mass, preferably 40% by mass to 80% by mass, based on the total mass of the flame-retardant layer.

[0021] The flame-retardant layer contains reinforcing fibers (described later) in an amount of 0 to 20% by mass, preferably 0 to 10% by mass, more preferably 0 to 5% by mass, even more preferably 0 to 3% by mass, and particularly preferably 0% by mass (i.e., no reinforcing fibers) relative to the total mass of the flame-retardant layer. When the reinforcing fiber content in the flame-retardant layer is within the above range, the flame retardancy of the laminate tends to be improved. On the other hand, if the flame-retardant layer does not contain reinforcing fibers, the difference in molding shrinkage rate between the flame-retardant layer and the fiber-reinforced resin layer will be large, which may result in warping of the molded product when the laminate is molded, for example, by two-color molding. In this case, although it can be addressed by adjusting the molding conditions, it is preferable to include a certain amount of reinforcing fibers in the flame-retardant layer and a larger amount of reinforcing fibers in the fiber-reinforced resin layer. In this case, the content of reinforcing fibers in the flame-retardant layer is preferably 5% by mass to 20% by mass of the total mass of the flame-retardant layer.

[0022] <<Thermoplastic resin>> The flame-retardant layer contains 20% by mass to 80% by mass, and preferably 20% by mass to 60% by mass, of a thermoplastic resin relative to the total mass of the flame-retardant layer. The thermoplastic resin contained in the flame-retardant layer is the same as the thermoplastic resin contained in the fiber-reinforced resin layer described below, and the preferred embodiments are also the same.

[0023] The flame-retardant layer may further contain a resin other than the above-mentioned thermoplastic resin. Examples of the resin other than the thermoplastic resin include a thermosetting resin, such as an epoxy resin, a thermosetting unsaturated polyester resin, and a phenol resin.

[0024] The content of resins other than the thermoplastic resins in the flame-retardant layer is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, and even more preferably 0 to 3% by mass, based on the total mass of the flame-retardant layer.

[0025] The thickness of the flame-retardant layer is preferably 0.1 to 30 mm, more preferably 0.3 to 20 mm, and even more preferably 0.5 to 10 mm. The thickness of the flame-retardant layer can be appropriately adjusted depending on the application and the flame retardancy required therefor.

[0026] In the present invention, the flame-retardant layer contains 20% to 80% by mass of a thermoplastic resin. This allows the content of the flame retardant to be increased compared to when the thermosetting resin is contained in the same amount as the thermoplastic resin, and is thought to further improve the flame retardancy of the resulting laminate. Note that when the flame-retardant layer contains a thermosetting resin, if the content of the flame retardant in the flame-retardant layer is high, the thermosetting resin is more likely to suffer a decrease in toughness due to crosslinking, and the mechanical properties are more likely to deteriorate.

[0027] <Fiber reinforced resin layer> The laminate according to the present invention includes a fiber-reinforced resin layer, which is a layer containing a thermoplastic resin and reinforcing fibers.

[0028] <<Thermoplastic resin>> Examples of thermoplastic resins include polycarbonate, styrene-based resin, polyamide resin, polyester resin, acrylic resins such as polyphenylene sulfide (PPS resin), modified polyphenylene ether (modified PPE resin), polyacetal (POM resin), liquid crystal polyester, polyarylate, and polymethyl methacrylate resin (PMMA), polyolefin resins such as vinyl chloride, polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polysulfone, polyethersulfone, polyketone, polyetherketone, polyetheretherketone (PEEK), polyethylene, and polypropylene, modified polyolefin resin, phenol resin, and phenoxy resin. Among these, from the viewpoint of light weight and excellent flame retardancy, the thermoplastic resin contained in the flame-retardant layer is preferably at least one resin selected from the group consisting of acrylic resin, polyolefin resin, polyamide resin, and polyester resin, more preferably at least one resin selected from the group consisting of polyamide resin, polyethylene, and polypropylene resin, and particularly preferably polyamide resin and / or polypropylene resin. These thermoplastic resins may be derived from fossil fuels or biomass raw materials.

[0029] From the viewpoint of excellent flame retardancy and impact strength, the thermoplastic resin contained in the fiber reinforced resin layer is preferably at least one resin selected from the group consisting of acrylic resin, polyolefin resin, polyamide resin and polyester resin, more preferably at least one resin selected from the group consisting of polyamide resin, polyethylene and polypropylene resin, and particularly preferably polyamide resin and / or polypropylene resin.

[0030] -Polypropylene resin- The polypropylene resin may be an unmodified polypropylene resin or a polypropylene resin containing a carboxylic acid structure or a carboxylate structure by a method such as modification. When both an unmodified resin and a polypropylene resin containing a carboxylic acid or a carboxylate structure are used, the mass ratio of unmodified to modified is preferably 99 / 1 to 80 / 20, more preferably 98 / 2 to 85 / 15, and even more preferably 97 / 3 to 90 / 10.

[0031] The polypropylene resin is, for example, a propylene-based polymer known as homopolypropylene, random polypropylene, block polypropylene, or modified polypropylene. The polypropylene resin is a polymer containing structural units derived from propylene, and is preferably a copolymer containing structural units derived from propylene and at least one structural unit derived from an olefin other than propylene selected from the group consisting of α-olefins, conjugated dienes, and non-conjugated dienes.

[0032] Examples of the α-olefins include α-olefins having 2 to 20 carbon atoms excluding propylene, such as ethylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 1-nonene, 1-octene, 1-heptene, 1-hexene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Among these, 1-butene, ethylene, 4-methyl-1-pentene, and 1-hexene are preferred, and 1-butene and 4-methyl-1-pentene are more preferred. Examples of conjugated and non-conjugated dienes include butadiene, ethylidene norbornene, dicyclopentadiene, and 1,5-hexadiene.

[0033] Two or more of the α-olefins, conjugated dienes, and non-conjugated dienes may be used in combination. Among these, the propylene resin is preferably a copolymer of propylene and an α-olefin. Examples of such copolymers include ethylene-propylene copolymers, propylene-1-butene copolymers, and ethylene-propylene-1-butene copolymers.

[0034] The propylene, α-olefin, conjugated diene and non-conjugated diene contained in the polypropylene resin may be derived from fossil fuels or biomass raw materials.

[0035] The proportion of propylene-derived structural units in the polypropylene resin is preferably 50 to 100 mol %, more preferably 60 to 100 mol %, and particularly preferably 70 to 100 mol %, based on the total structural units of the polypropylene resin, in order to improve the mechanical properties of the resulting laminate.

[0036] The polypropylene resin may have a structure containing, for example, an element of Groups 15 to 17 of the periodic table. Examples of the structure containing an element of Groups 15 to 17 of the periodic table include functional groups such as a carboxylic anhydride group, a carboxylic acid group, an amino group, an acid amide group, and a halogen group. Such a structure can be introduced by a known method such as a radical grafting reaction. Examples of Group 17 elements include halogen atoms such as chlorine atoms. Examples of Group 16 elements include oxygen atoms and sulfur atoms, with oxygen atoms being preferred. Examples of Group 15 elements include nitrogen atoms. Of these, oxygen atoms are preferred. That is, the structure containing an element from Groups 15 to 17 of the periodic table may preferably be a carboxylic acid (salt). The carboxylic acid (salt) is preferably a carboxylic acid group or a carboxylic anhydride group, more preferably a group having a maleic anhydride structure.

[0037] When the polypropylene resin has a structure containing an element from Groups 15 to 17 of the periodic table, the content of the element is preferably 0.0003 to 5 mass%, more preferably 0.0005 to 4.5 mass%, even more preferably 0.0008 to 4.3 mass%, and particularly preferably 0.001 to 4 mass%, relative to the total mass of the polypropylene resin.

[0038] The content can be calculated from the ratio of each component charged in the grafting reaction, for example, or can be determined using an elemental analyzer such as an elemental analyzer (for example, varioELIII type: manufactured by Elemental).

[0039] The polypropylene resin preferably contains an unmodified polypropylene resin and an acid-modified polypropylene resin.

[0040] The melt flow rate (MFR) of the polypropylene resin measured under conditions of 230° C. and a load of 2.16 kg is usually 3 to 100 g / 10 min, and preferably 15 to 100 g / 10 min. The MFR can be determined by the measurement method described in the Examples below.

[0041] The fiber reinforced resin layer contains 30% to 90% by mass of the thermoplastic resin, preferably 30% to 80% by mass, and more preferably 35% to 60% by mass, based on the total mass of the fiber reinforced resin layer.

[0042] The fiber-reinforced resin layer may further contain a resin other than the thermoplastic resin. Examples of the resin other than the thermoplastic resin include a thermosetting resin, such as an epoxy resin, a thermosetting unsaturated polyester resin, and a phenol resin.

[0043] The content of resins other than the above thermoplastic resins in the fiber reinforced resin layer is preferably 0 to 10 mass %, more preferably 0 to 5 mass %, and even more preferably 0 to 3 mass %, relative to the total mass of the fiber reinforced resin layer. In particular, when the resin other than the thermoplastic resin is a thermosetting resin, it is more preferable that the resin is substantially free of the thermosetting resin from the viewpoint of suppressing deterioration of mechanical properties due to a decrease in toughness caused by crosslinking. Note that "substantially free of the thermosetting resin" means that unavoidable components are allowed to be mixed in.

[0044] <<Reinforced fiber>> Examples of reinforcing fibers include carbon fibers, glass fibers, aramid fibers, alumina fibers, silicon carbide fibers, boron fibers, etc. From the viewpoint of improving the impact strength of the laminate, the reinforcing fibers preferably include at least one type of fiber selected from the group consisting of carbon fibers and glass fibers.

[0045] <<Carbon fiber>> Various known carbon fibers can be used as the carbon fiber. Examples of the carbon fiber include polyacrylonitrile-based, rayon-based, pitch-based, polyvinyl alcohol-based, regenerated cellulose-based, and pitch-based carbon fibers produced from mesophase pitch. The carbon fiber may be a general-purpose fiber or a high-strength fiber. The carbon fiber may also be a long fiber, a short fiber, or a recycled fiber.

[0046] <<Glass fiber>> The glass fiber is not particularly limited, and examples thereof include fibers made of glass compositions such as A-glass, C-glass, D-glass, E-glass, and S-glass. Among these, fibers made of E-glass (alkali-free glass) are particularly preferred.

[0047] The reinforcing fibers may be short fibers or long fibers. The short fibers may be chopped fiber (cut fiber) short fibers or pulp-like short fibers having fibrils. The reinforcing fibers may be single fibers or multiple twisted single fibers.

[0048] The average fiber length of the reinforcing fibers is preferably 0.01 mm or more, more preferably 0.1 mm or more, and even more preferably 1 mm or more, and is preferably 100 mm or less, more preferably 50 mm or less, and even more preferably 30 mm or less. When the average fiber length is within the above range, the reinforcing effect of the reinforcing fibers on mechanical properties tends to be sufficiently exhibited, and the dispersion of the reinforcing fibers in the fiber-reinforced resin layer is improved, so that the appearance tends to be good. The ratio of the number of fibers having a fiber length of less than 0.1 mm to the total number of reinforcing fibers is preferably 18% or less.

[0049] The average fiber diameter of the reinforcing fibers is preferably 1 μm or more, more preferably 5 μm or more, and preferably 30 μm or less, more preferably 20 μm or less. In such an embodiment, the reinforcing fibers are less likely to break during molding, the impact strength of the resulting molded article tends to be high, the appearance of the molded article is good, and a sufficient reinforcing effect is obtained in the mechanical properties such as rigidity and heat resistance of the molded article.

[0050] The average fiber length and average fiber diameter can be determined, for example, by taking a photograph of the reinforcing fibers using an optical microscope, measuring the length or diameter of 100 reinforcing fibers randomly selected from the photograph, and calculating the arithmetic mean of each.

[0051] Among the above, preferred examples of the form of glass fiber include "glass roving" in which a single fiber or a plurality of twisted fibers is continuously wound up, "chopped strands" in which the fibers are cut to an average fiber length of 1 to 10 mm, and "milled fiber" in which the fibers are pulverized to an average fiber length of about 10 to 500 μm.

[0052] The reinforcing fibers may be fibers that have not been surface-treated (hereinafter referred to as "fibers (C0)"), or may be fibers that have been surface-treated (hereinafter referred to as "surface-treated fibers (C1)").

[0053] For example, the "surface-treated fiber (C1)" may be a fiber that has been surface-treated with various sizing agents (hereinafter referred to as "sizing agent-treated fiber (C1A)"). The "sizing agent-treated fiber (C1A)" often contains the above-mentioned fiber (C0) and a sizing agent that coats the fiber (C0). Examples of the sizing agent include acrylic sizing agents, urethane sizing agents, acid copolymer sizing agents, etc. Among these, acid copolymer sizing agents are preferred as the sizing agent.

[0054] Here, when the "sizing agent-treated fiber (C1A)" is a glass fiber roving that has been surface-treated with a sizing agent (hereinafter referred to as "sizing agent-treated glass fiber roving"), the sizing agent contained in the "sizing agent-treated glass fiber roving" is preferably an acid copolymer-based sizing agent, since the resin component is sufficiently impregnated into the sizing agent-treated fiber. Acrylic sizing agents are also suitable sizing agents.

[0055] On the other hand, when the "sizing agent-treated fiber (C1A)" is a fiber other than the "sizing agent-treated glass fiber roving," for example, a chopped strand that has been surface-treated with a sizing agent (hereinafter referred to as "sizing agent-treated chopped strand"), the sizing agent contained in the "sizing agent-treated chopped strand" is not limited to an acid copolymer-based sizing agent, and may be an acrylic-based sizing agent, a urethane-based sizing agent, or any other sizing agent than the acid copolymer-based sizing agent. Even if the "sizing agent-treated chopped strands" contain a sizing agent other than an acid copolymer-based sizing agent, they are preferred because they are sufficiently impregnated with the resin component, just like the "sizing agent-treated chopped strands" that contain an acid copolymer-based sizing agent.

[0056] The reinforcing fibers may contain, as necessary, one or more components selected from the group consisting of silane coupling agents, titanate coupling agents, aluminum coupling agents, zirconium coupling agents, borane coupling agents, curing catalysts, lubricants, fillers, thixotropy agents, tackifiers, waxes, heat stabilizers, light resistance stabilizers, fluorescent brighteners, foaming agents, pH adjusters, leveling agents, antigelling agents, dispersion stabilizers, antioxidants, radical scavengers, heat resistance imparting agents, inorganic fillers, organic fillers, plasticizers, reinforcing agents, antibacterial agents, mildew inhibitors, rust inhibitors, thermoplastic resins, thermosetting resins, pigments, dyes, conductivity imparting agents, antistatic agents, moisture permeability improvers, water repellents, oil repellents, hollow foams, crystal water-containing compounds, flame retardants, water absorbents, moisture absorbents, deodorizers, foam stabilizers, antifoaming agents, antifungal agents, preservatives, antialgae agents, pigment dispersants, antiblocking agents, and hydrolysis inhibitors.

[0057] Examples of surface treatment methods for reinforcing fibers using a sizing agent include applying the sizing agent to the surface of the reinforcing fibers with an applicator or the like, immersing the reinforcing fibers in the sizing agent, spraying the sizing agent in a mist onto the reinforcing fibers, and contacting the reinforcing fibers with a roller to which the sizing agent is attached. The surface treatment methods may be either batch or continuous.

[0058] When reinforcing fibers are surface-treated with a sizing agent, the mass proportion of the sizing agent in the reinforcing fibers, i.e., the loss on ignition, is preferably 0.1 to 1.5 mass% relative to the total mass of the reinforcing fibers. The mass proportion of the sizing agent (loss on ignition) is measured, for example, on the fibers obtained by applying the sizing agent to the reinforcing fibers using an applicator or the like and drying the fibers to completely volatilize the volatile substances. When the sizing agent applied to the surface of carbon or glass fibers has a loss on ignition of 0.1 mass% or more, this is preferable because it can stabilize the interface between the resin and the reinforcing fibers and exhibit heat resistance. On the other hand, when the sizing agent applied to the surface of the reinforcing fibers has a loss on ignition of 1.5 mass% or less, this is preferable because it can improve physical properties such as heat resistance.

[0059] The ignition loss of the sizing agent in the reinforcing fibers is a value measured in accordance with JIS R 3420 (2006) 7.3.2. The surface-treated reinforcing fibers may be bundled to a predetermined number, wound up, and then cut and / or crushed as necessary to be processed into chopped strands, milled fibers, yarns, rovings, etc.

[0060] The fiber-reinforced resin layer may further contain fibers other than the reinforcing fibers (hereinafter also referred to as "other fibers"), as long as the effects of the present invention are achieved. Examples of other fibers include natural fibers such as cotton fibers, silk fibers, wood fibers, and cellulose fibers; and synthetic fibers made of synthetic resins such as wholly aromatic polyamide (aramid), wholly aromatic polyester, wholly aromatic polyesteramide, wholly aromatic polyether, wholly aromatic polycarbonate, wholly aromatic polyazomethine, polyphenylene sulfide, polyparaphenylene benzobisoxazole, poly(para-phenylene benzobisthiazole), polybenzimidazole, polyether ether ketone, polyamideimide, polyimide, polytetrafluoroethylene, polyvinyl alcohol, polyolefin, polyarylate, and fluorine-based polymers.

[0061] The fiber reinforced resin layer may contain any additives as needed in addition to the reinforcing fibers and the thermoplastic resin. Examples of the optional additives include nucleating agents, antiblocking agents, pigments, fillers, dyes, lubricants, plasticizers, release agents, antioxidants, ultraviolet absorbers, antibacterial agents, surfactants, antistatic agents, weather resistance stabilizers, heat resistance stabilizers, antislip agents, crystallization aids, antifogging agents, antiaging agents, hydrochloric acid absorbers, impact modifiers, crosslinking agents, co-crosslinking agents, crosslinking aids, adhesives, softeners, and processing aids. These additives may be used alone or in combination of two or more.

[0062] The content of the reinforcing fibers contained in the fiber-reinforced resin layer is preferably at least 10% by mass larger, and more preferably at least 20% by mass larger, than the content of the reinforcing fibers contained in the flame-retardant layer.

[0063] The fiber-reinforced resin layer contains reinforcing fibers in an amount of 10% by mass to 70% by mass relative to the total mass of the fiber-reinforced resin layer, preferably 20% by mass to 60% by mass relative to the total mass of the fiber-reinforced resin layer, and more preferably 40% by mass to 60% by mass relative to the total mass of the fiber-reinforced resin layer.

[0064] Furthermore, from the viewpoint of sufficiently increasing the impact resistance strength of the laminate, the content of the flame retardant in the fiber reinforced resin layer is preferably 0 mass% or more and less than 20 mass%, more preferably 0 mass% to 10 mass%, even more preferably 0 mass% to 5 mass%, and particularly preferably 0 mass% to 3 mass%, relative to the total mass of the fiber reinforced resin layer.

[0065] The density of the fiber reinforced resin layer is preferably 0.9 to 1.8 g / cm 3 and more preferably 1.0 to 1.7 g / cm 3 is. The density of the fiber reinforced resin layer can be determined by the measurement method described in the examples below.

[0066] The thickness of the fiber reinforced resin layer is preferably 0.5 to 30 mm, more preferably 1.0 to 20 mm, even more preferably 2.0 to 10 mm, and particularly preferably 3.0 to 10 mm. When the thickness of the fiber reinforced resin layer is equal to or greater than the above lower limit, warping of the laminate tends to be suppressed and impact resistance tends to be further improved. Furthermore, when the thickness of the fiber reinforced resin layer is equal to or less than the above upper limit, moldability tends to be excellent. The thickness of the fiber reinforced resin layer can be appropriately adjusted depending on the application and the mechanical strength required therefor.

[0067] <<Method for forming fiber-reinforced resin layer>> The method for forming the fiber-reinforced resin layer is not particularly limited, and conventionally known methods can be used. For example, a resin and the carbon fiber or glass fiber are mixed and molded into a fiber-reinforced film, fiber-reinforced sheet, fiber-reinforced plate, etc., by using extrusion molding, injection molding, vacuum molding, pressure molding, press molding, etc., to form the fiber-reinforced resin layer. Alternatively, a masterbatch-like pellet composed of the reinforcing fiber and thermoplastic resin can be mixed with thermoplastic resin pellets, and the fiber-reinforced resin layer can be formed by injection molding, etc. Alternatively, a mixed mat composed of the reinforcing fiber and thermoplastic resin fiber can be used to form a fiber-reinforced resin layer by press molding, etc., at a temperature equal to or higher than the flow initiation temperature of the thermoplastic resin fiber.

[0068] <<Electromagnetic wave shielding filler>> From the viewpoint of preventing external leakage of electromagnetic noise generated from lithium-ion batteries and the like, the fiber-reinforced resin layer or the flame-retardant layer may contain an electromagnetic wave shielding filler. From the viewpoint of achieving both mechanical properties and electromagnetic wave shielding properties of the laminate, it is preferable that the electromagnetic wave shielding filler be contained in the flame-retardant layer. In this specification, when the flame-retardant layer contains an electromagnetic wave shielding filler, the flame-retardant layer may be referred to as a "flame-retardant / electromagnetic wave shielding layer."

[0069] From the viewpoint of improving flame retardancy, electromagnetic wave shielding properties, and mechanical properties, the content of the electromagnetic wave shielding filler in the fiber reinforced resin layer and the flame retardant layer is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and even more preferably 1 to 10% by mass, based on the total mass of the fiber reinforced resin layer and the flame retardant layer (total mass of the fiber reinforced resin layer and the flame retardant layer).Similarly, the content of the electromagnetic wave shielding filler in the fiber reinforced resin layer and the flame retardant layer is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and even more preferably 1 to 10% by mass, based on the total mass of the flame retardant layer.

[0070] The electromagnetic wave shielding filler is not particularly limited as long as it can shield electromagnetic waves, and may be one that reflects electromagnetic waves or one that absorbs electromagnetic waves. As the electromagnetic wave shielding filler, a publicly known and publicly used electromagnetic wave shielding filler can be used. Examples of the electromagnetic wave shielding filler include carbon-based electromagnetic wave shielding fillers and metal-based electromagnetic wave shielding fillers.

[0071] Examples of carbon-based electromagnetic wave shielding fillers include carbon nanotubes, carbon black, graphite, graphene, and graphite.

[0072] Examples of metal-based electromagnetic wave shielding fillers include metals such as gold, silver, platinum, aluminum, copper, iron, nickel, palladium, chromium, and stainless steel, as well as metal powders, metal flakes, and metal fibers made from oxides of these metals.

[0073] As the metallic electromagnetic wave shielding filler, a filler in which soft magnetic powder pieces are coated with a conductive metal can also be preferably used. The soft magnetic powder pieces are preferably silicon steel, sendust alloy, permalloy alloy, Co-based or Fe-based amorphous alloy powder pieces, or ferrite-based oxide powder pieces. The conductive metal has the same meaning as the conductive metal in the electromagnetic wave shielding filler contained in the electromagnetic wave shielding layer described later, and the preferred embodiments are also the same.

[0074] While known methods can be used to coat the conductive metal, electroless plating is particularly preferred. This method allows for a consistent, uniform coating on the powder surface. Electroless plating can be performed according to conventional methods, such as washing the soft magnetic powder to activate its surface, adding it to an aqueous solution containing a complexing agent and a reducing agent, and then dripping a conductive metal salt into the solution. Examples of complexing agents include ammonia water, salts of ethylenediaminetetraacetic acid, nitrilotriacetic acid, and triethylenetetraminehexaacetic acid. Examples of reducing agents include formalin, hydrazine and its derivatives, tartaric acid, and glucose. These can be selected appropriately depending on the conductive metal used. Examples of conductive metal salts include nitrates and sulfates.

[0075] The preferred amount of conductive metal coating varies depending on the type, size, and shape of the soft magnetic powder pieces, and the type of conductive metal. For example, ferrite-based oxides have a lighter specific gravity than alloy-based powder pieces, so even if the powder pieces have the same shape and coating thickness, the metal mass ratio (%) of the coated powder pieces will be higher when ferrite-based powder pieces are used than when alloy-based powder pieces are used. For example, when iron-based soft magnetic alloy powder pieces with an average particle size of 5 to 200 μm and an aspect ratio of 10 to 50 are used and coated with silver, copper, or nickel, the coating amount is appropriately about 5 to 75 mass% per unit mass of the coated powder pieces, preferably 10 to 50 mass%, and even more preferably 10 to 20 mass%.

[0076] <<Electromagnetic wave shielding layer>> The laminate may further include an electromagnetic wave shielding layer. When the laminate includes an electromagnetic wave shielding layer, it is preferably provided between the flame retardant layer and the fiber reinforced resin layer.

[0077] The electromagnetic wave shielding layer is not particularly limited as long as it is a layer that shields electromagnetic waves, and a publicly known and commonly used electromagnetic wave shielding layer can be used. The electromagnetic wave shielding layer is preferably, for example, a layer containing a binder resin and the above-mentioned electromagnetic wave shielding filler. The binder resin contained in the electromagnetic wave shielding layer is not particularly limited, and examples thereof include thermoplastic resins and thermosetting resins. The thermoplastic resins and thermosetting resins have the same meanings as the thermoplastic resins and thermosetting resins in the above-mentioned fiber-reinforced resin layer, and preferred embodiments are also the same.

[0078] Examples of conductive metals constituting the electromagnetic wave shielding filler include metals such as gold, silver, platinum, aluminum, copper, iron, nickel, palladium, chromium, and stainless steel, as well as metal powders, metal flakes, and metal fibers made from oxides of these metals. Among these, the conductive metal is preferably made of at least one metal selected from silver, nickel, copper, and stainless steel, and more preferably made of at least one metal selected from copper and stainless steel.

[0079] The electromagnetic wave shielding filler is preferably in the form of fibers. The diameter of the electromagnetic wave shielding filler is preferably 1 μm to 20 μm, and more preferably 4 μm to 8 μm. The length of the electromagnetic wave shielding filler is preferably 0.5 mm to 5.0 mm, and more preferably 1 mm to 2 mm.

[0080] The content of the electromagnetic wave shielding filler is preferably 0.1 mass % or more and less than 5.0 mass %, more preferably 0.1 mass % to 3 mass %, and even more preferably 0.3 mass % to 1 mass %, relative to the total solid content of the electromagnetic wave shielding layer.

[0081] The thickness of the electromagnetic wave shielding layer is preferably 0.5 to 30 mm, more preferably 0.5 to 20 mm, and even more preferably 0.5 to 10 mm.

[0082] The laminate according to the present invention may include a plurality of each of the above-described layers. Examples of the layer configuration of the laminate according to the present invention include "flame-retardant layer / fiber-reinforced resin layer," "flame-retardant layer / fiber-reinforced resin layer / flame-retardant layer," "flame-retardant layer / electromagnetic wave shielding layer / fiber-reinforced resin layer," "flame-retardant layer / fiber-reinforced resin layer / electromagnetic wave shielding layer," "electromagnetic wave shielding layer / flame-retardant layer / fiber-reinforced resin layer," "flame-retardant layer / fiber-reinforced resin layer / flame-retardant layer / electromagnetic wave shielding layer," "flame-retardant layer / electromagnetic wave shielding layer / fiber-reinforced resin layer / flame-retardant layer," and "electromagnetic wave shielding layer / flame-retardant layer / fiber-reinforced resin layer / flame-retardant layer."

[0083] The laminate according to the present invention may include layers other than the flame-retardant layer, fiber-reinforced resin layer, and electromagnetic wave shielding layer (hereinafter also referred to as "other layers"). Examples of the other layers include a protective layer and an insulating layer.

[0084] The laminate according to the present invention is excellent in flame retardancy and impact resistance, and therefore can be applied to parts that require flame retardancy and impact resistance. The material can be applied to parts or housings in a variety of applications requiring impact resistance and flame retardancy, such as automobiles, ships, railway vehicles, aircraft, home appliances, office equipment, AV equipment, business machines, building and housing facilities, machine tools, industrial machinery, etc. Furthermore, the material can be applied to housings for millimeter-wave radars and battery cases for nonaqueous electrolyte secondary batteries, which will be described later.

[0085] <Battery case for non-aqueous electrolyte secondary battery> The battery case for a non-aqueous electrolyte secondary battery according to the present invention (hereinafter also simply referred to as "battery case") is a battery case for a non-aqueous electrolyte secondary battery made using the above laminate. Because the battery case uses the above laminate, it has excellent flame retardancy and impact resistance. Furthermore, when the battery case uses the above laminate including a flame retardant / electromagnetic wave shielding layer, it has excellent electromagnetic wave shielding properties in addition to flame retardancy and impact resistance. The battery case according to the present invention is not particularly limited as long as it can house batteries for non-aqueous electrolyte secondary batteries, and examples thereof include a case molded to house a lithium-ion battery. When the battery case according to the present invention is applied to a battery pack for an electric vehicle, it is lighter than a metal case, and therefore the driving distance of the electric vehicle can be extended.

[0086] In the battery case, the flame-retardant layer is preferably disposed on the inside of the battery case, and more preferably on the inner surface of the battery case. The battery case usually contains a non-aqueous electrolyte, an electrode group, etc. The "inside of the battery case" refers to the side of the battery case that contains the non-aqueous electrolyte, the electrode group, etc. The "inside surface of the battery case" refers to the surface inside the battery case. Such a configuration can be implemented as a laminate, for example, one having a layer structure of "flame-retardant layer / fiber-reinforced resin layer" or one having a layer structure of "flame-retardant layer / fiber-reinforced resin layer / flame-retardant layer".

[0087] The battery case may further include an electromagnetic wave shielding layer. When the battery case further includes an electromagnetic wave shielding layer, it is preferable that the laminate also includes the electromagnetic wave shielding layer. The electromagnetic wave shielding layer in the battery case has the same meaning as the electromagnetic wave shielding layer in the laminate, and preferred embodiments are also the same. In the battery case, the flame-retardant layer and the fiber-reinforced resin layer may be laminated in contact with each other, or the electromagnetic wave shielding layer may be laminated between the flame-retardant layer and the fiber-reinforced resin layer. From the viewpoint of preventing external leakage of electromagnetic wave noise generated from a lithium ion battery or the like, the electromagnetic wave shielding layer is preferably laminated between the flame-retardant layer and the fiber-reinforced resin layer, and more preferably the electromagnetic wave shielding layer is laminated between the flame-retardant layer and the fiber-reinforced resin layer, and the flame-retardant layer and the fiber-reinforced resin layer are laminated in contact with each other. The battery case may further include a layer other than the electromagnetic wave shielding layer on the surface opposite to the flame-retardant layer (that is, on the fiber-reinforced resin layer). The other layer may be, for example, a protective layer, etc. The protective layer may be, for example, a layer made of the above-mentioned thermoplastic resin.

[0088] In the battery case, the fiber-reinforced resin layer or the flame-retardant layer in the laminate may contain an electromagnetic wave shielding filler. The electromagnetic wave shielding filler in the battery case has the same meaning as the electromagnetic wave shielding filler in the laminate, and the preferred embodiments are also the same.

[0089] The shape of the battery case is not particularly limited as long as it can accommodate a secondary battery, and may be, for example, a square shape (flat rectangular parallelepiped), a cylindrical shape, or a bag shape. The battery case may be equipped with an external terminal, a liquid inlet, a gas release valve, a current interrupter (CID), and the like.

[0090] <<How to make a battery case>> The method for forming the battery case is not particularly limited, and any known molding method can be used. For example, the battery case can be obtained by molding using a blow molding method, an injection molding method, a press molding method, an extrusion molding method, an extrusion blow molding method, an injection blow molding method, a vacuum molding method, etc. Among the above molding methods, the battery case is preferably molded by an injection molding method.

[0091] <Nonaqueous electrolyte secondary battery> A battery for a non-aqueous electrolyte secondary battery according to the present invention includes the battery case for a non-aqueous electrolyte secondary battery. The nonaqueous electrolyte secondary battery may include a conventionally known battery for nonaqueous electrolyte secondary batteries, as long as it includes the above-mentioned battery case. A conventionally known battery for nonaqueous electrolyte secondary batteries may have a configuration including, for example, an electrode assembly having a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, and the electrode assembly is disposed in a battery case together with a nonaqueous electrolyte. A suitable example of the non-aqueous electrolyte secondary battery is a lithium ion secondary battery containing a non-aqueous electrolyte.

[0092] <<Positive electrode>> The positive electrode preferably includes a positive electrode current collector and a positive electrode composite layer formed on a main surface of the positive electrode current collector. The positive electrode current collector may be, for example, an aluminum (Al) foil. The Al foil may be a pure Al foil or an Al alloy foil. The positive electrode current collector may have a thickness of, for example, 10 to 30 μm.

[0093] <<Positive electrode composite layer>> The positive electrode mixture layer preferably contains a positive electrode active material, a conductive material, and a binder. The positive electrode mixture layer may contain, for example, 80 to 98 mass % of the positive electrode active material, 1 to 15 mass % or less of the conductive material, and 1 to 5 mass % or less of the binder. The positive electrode mixture layer may have a thickness of, for example, 100 to 200 μm.

[0094] <<Positive electrode active material, conductive material and binder>> The positive electrode active material, conductive material, and binder are not particularly limited. The positive electrode active material is, for example, LiCoO2, LiNiO2, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (NCM: nickel cobalt manganese oxide), LiMnO2, LiMn2O4, LiFePO4, etc. may also be used. The conductive material may be, for example, acetylene black (AB), furnace black, vapor grown carbon fiber (VGCF), graphite, or the like. The binder may be, for example, PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), or the like.

[0095] <<Negative electrode>> The negative electrode preferably includes a negative electrode current collector and a negative electrode composite layer formed on a main surface of the negative electrode current collector. The negative electrode current collector may be, for example, a copper (Cu) foil. The negative electrode current collector may have a thickness of, for example, about 5 to 20 μm.

[0096] <<Negative electrode composite layer>> The negative electrode mixture layer preferably contains a negative electrode active material and a binder. The negative electrode mixture layer may contain, for example, 95 to 99 mass % of the negative electrode active material and 1 to 5 mass % of the binder. The negative electrode mixture layer may have a thickness of, for example, about 50 to 150 μm.

[0097] <<Negative electrode active material and binder>> The negative electrode active material and binder are not particularly limited. The negative electrode active material may be, for example, graphite, graphitizable carbon, non-graphitizable carbon, silicon, silicon oxide, tin, tin oxide, or the like. These may also be coated with amorphous carbon. The binder may be, for example, carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), or the like.

[0098] <<Non-aqueous electrolyte>> The nonaqueous electrolyte contains a lithium salt, an additive, and a solvent. The lithium salt may be, for example, LiPF6, LiFSI, etc. The additive may be, for example, Li[B(C2O4)], LiPO2F2, vinylene carbonate (VC), vinyl ethylene carbonate (VEC), fluoroethylene carbonate (FEC), ethylene sulfite (ES), propane sultone (PS), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), LiBF2(C2O4), LiPF2(C2O4)2, etc. The solvent may be, for example, a mixture of a cyclic carbonate and a chain carbonate. The mixing ratio of the cyclic carbonate to the chain carbonate may be, for example, cyclic carbonate:chain carbonate = 1:9 to 5:5 by volume. The cyclic carbonate may be, for example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc. The chain carbonate may be, for example, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), etc.

[0099] <<Separator>> Suitable examples of the separator include microporous films such as polyethylene (PE) and polypropylene (PP). The separator may have a single-layer structure of PE, or a three-layer structure in which a PP film, a PE film, and a PP film are laminated in this order. The thickness of the separator may be, for example, about 9 to 30 μm. When the separator has the above-mentioned three-layer structure, the thickness of the PE layer may be, for example, about 3 to 10 μm, and the thickness of the PP layer may be, for example, about 3 to 10 μm. The pore size and porosity of the separator may be appropriately adjusted so that the air permeability becomes a desired value. The separator may be a laminate of multiple microporous membranes, or may have a heat-resistant layer containing an inorganic filler and a binder formed on the surface thereof. The inorganic filler contained in the heat-resistant layer may be, for example, alumina, boehmite, titania, zirconia, magnesia, etc. The binder contained in the heat-resistant layer may be, for example, PVdF, aramid, SBR, PTFE, etc. The amount of binder contained in the heat-resistant layer may be 2 to 30 mass %, and the thickness of the heat-resistant layer may be, for example, about 3 to 10 μm. [Example]

[0100] The present invention will be explained in more detail below based on examples, but the present invention is not limited to these examples. The methods for measuring various physical properties are as follows.

[0101] (raw materials) Homopolypropylene: J137G (Prime Polymer Co., Ltd., MFR: 30g / 10min at 230°C and 2.16kg load, conforming to ASTM D1238) Glass fiber masterbatch: Mostron L-5071PL9 (manufactured by Prime Polymer Co., Ltd., glass fiber content: 50% by mass, polypropylene content: 50% by mass) Carbon fiber masterbatch: a masterbatch containing 40% by mass of carbon fiber, 54% by mass of polypropylene, and 6% by mass of polyamide, prepared in Production Example 2 below. Phosphorus-based flame retardant masterbatch: Brand name MB32B (Manufacturer: JLS), Phosphorus-based flame retardant (Melamine polyphosphate: concentration 39% by mass, Polyphosphoric acid salt, compound: concentration 36% by mass): 75% by mass, Polypropylene (PP): 25% by mass Brominated flame retardant masterbatch: Daifunen EH931 (manufacturer: Dainichiseika Color & Chemicals Mfg. Co., Ltd.), brominated flame retardant (ethylene bispentabromobiphenyl: concentration 54% by mass, antimony trioxide: concentration 21% by mass, polyethylene (PE): 25% by mass) Carbon nanotube masterbatch: a masterbatch containing 15% by mass of carbon nanotubes prepared in Production Example 1 below, 83% by mass of polypropylene, and a total of 2% by mass of a dispersant, stabilizer, and processing stabilizer.

[0102] <Production Example 1> (Manufacturing carbon nanotube master batch) A carbon nanotube masterbatch was produced using the following materials and by the following method.

[0103] -raw materials- Multi-walled carbon nanotubes: Nanocyl's "NC7000" (average diameter: 9.5 mm, average length: 1.5 μm, form: powder, layer structure: multi-layered) Polypropylene: Prime Polypro (registered trademark) J707G manufactured by Prime Polymer Co., Ltd. Dispersant: Idemitsu Kosan Co., Ltd.'s "Elmodu S400" (low stereoregular polyolefin, Mw=45,000, (Mw / Mn)=2, softening point: 93°C) Hindered phenol antioxidant (BASF Japan Ltd.'s "Irganox 1010", chemical formula: pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] Phosphorus-based processing stabilizer (BASF Japan Ltd.'s "Irgafos168", chemical formula: tris(2,4-di-tert-butylbenzene) phosphite)

[0104] -Manufacturing method- 91% by mass of multi-walled carbon nanotubes and 9% by mass of dispersant were placed in an FM mixer ("FM10C / I" manufactured by Nippon Coke Co., Ltd., capacity: 9 L). These were stirred at a stirring temperature of 140°C, a stirring time of 60 minutes, and a screw rotation speed of 1000 rpm. This produced a mixed powder.

[0105] Next, 16.5% by mass of the mixed powder and 83.5% by mass of polypropylene were dry-blended to obtain a dry blend. Specifically, the mixed powder and polypropylene were fed into a twin-screw extruder (Toshiba Machine Co., Ltd.'s "TEM-35B," screw diameter: 35 mm, L / D: 32, vent type), and a strand-like material with a diameter of 3 mm was obtained from the outlet of the twin-screw extruder. The strand-like material was placed in a water bath, cooled, and cut with a strand cutter. This resulted in pellets, which were the dry blend.

[0106] 99.6 parts by mass of the obtained pellets, 0.2% by mass of a hindered phenol-based antioxidant, and 0.2% by mass of a phosphorus-based processing stabilizer were charged into a kneading extruder ("KZW-15TW" manufactured by Technovel Co., Ltd., screw diameter: 15 mmΦ), and kneaded and granulated at a kneading temperature of 230°C and a screw rotation speed of 100 rpm. This produced a carbon nanotube masterbatch.

[0107] <Production Example 2> (Manufacturing carbon fiber master batch) A carbon fiber masterbatch was produced using the following materials and by the following method.

[0108] -raw materials- Carbon fiber: Toho Tenax "TENAX (registered trademark) HTS40 12K" Density: 1.79 g / cm 3 ) Polypropylene: Homopolypropylene manufactured by Prime Polymer Co., Ltd., conforming to ASTM D1238, with a MFR of 220 g / 10 min at 230°C and a load of 2.16 kg. Polyamide: UBESTA® 3012U, a polyamide 12 manufactured by Ube Industries, Ltd. (melting point: 180°C, MFR: 17g / 10min (measured in accordance with ISO 1133 at 190°C and 1000g load)) Acid-modified polyolefin resin: "Admer QE800" manufactured by Mitsui Chemicals, Inc.

[0109] -Manufacturing method- 76.4 parts by mass of the polypropylene, 10.0 parts by mass of polyamide, and 13.6 parts by mass of acid-modified polyolefin, which are components used as the matrix resin, were placed in the hopper of a screw-type extruder whose temperature was adjusted to 250°C. The carbon fiber roving was opened in a fiber-opening process, and the resin and carbon fiber from the extruder were fed to an impregnation die to obtain strands with a diameter of 1 mm so that the carbon fiber content was 40% by mass. After cooling and solidifying, a carbon fiber masterbatch was obtained using a strand cutter.

[0110] Examples 1 to 8 The above raw materials were mixed in the proportions listed in Table 1 and molded into flat plate specimens using a two-color injection molding machine (JSW, 180 ton injection molding machine) with two barrels: a main unit and a subunit. Specifically, the raw materials for the flame-retardant layer were placed in the main unit, and the raw materials for the fiber-reinforced resin layer were placed in the subunit. The molding conditions were a barrel temperature of 240°C, an injection speed of 15 mm / s, a back pressure of 8 MPa (main unit side) and 3 MPa (subunit side), and a mold temperature of 60°C. The subunit side was injected, and then the movable side of the mold was retracted to create a space for molding the second layer. Then, the main unit side was injected, yielding a two-layer flat plate laminate with a flame-retardant layer and a fiber-reinforced resin layer. The dimensions of the flat plate laminate were 13 cm x 10 cm. The thicknesses of each layer are shown in Table 1.

[0111] (Comparative Examples 1 and 2) A raw material mixture was obtained by dry blending the above raw materials in the ratios shown in Table 2. This raw material mixture was loaded into only the main unit of an injection molding machine (180t injection molding machine manufactured by JSW Co., Ltd.), and injection molding was carried out using only the main unit without using a sub-unit, at a barrel temperature of 240°C, an injection speed of 15 mm / s, a back pressure of 3 MPa, and a mold temperature of 60°C, to obtain a single-layer molded product measuring 13 cm x 10 cm.

[0112] [Table 1]

[0113] In Tables 1 and 2, "PP" represents polypropylene resin, "PA" represents polyamide, "GF" represents glass fiber, "CF" represents carbon fiber, and "PE" represents polyethylene.

[0114] [Table 2]

[0115] The flat laminates and single-layer molded articles obtained in Examples 1 to 8 and Comparative Examples 1 and 2 were subjected to measurement and evaluation of physical properties by the following methods.

[0116] <<Evaluation>> [Physical property measurement method] (1) Mechanical properties: Charpy impact strength Strip test pieces (dimensions: 80 mm × 10 mm × 2.5 mmt) were prepared by cutting from the flat laminates and single-layer molded bodies obtained in Examples 1 to 8 and Comparative Examples 1 and 2. The impact strength of each test piece was measured using a Charpy impact tester, a thermostatic chamber-equipped impact tester, Model DG-UB (manufactured by Toyo Seiki Seisakusho). The results are shown in Tables 1 and 2. The measurement conditions for the impact test were a test temperature of 23°C, a hammer capacity of 4J (for notched test specimens) and 15J (for unnotched test specimens). The Charpy impact strength was measured in accordance with JIS K7111-1 and JIS K7111-2. It can be said that the higher the Charpy impact strength value, the better the impact resistance strength.

[0117] (2) Flame retardant (UL94 5V) The above flat test specimens were subjected to a combustion test in accordance with the UL94 5V standard. The center of the flame-retardant layer of the test specimen was exposed to flame, and it was checked whether or not a hole had been formed. If no hole had been formed, it was considered a pass (OK), and if a hole had been formed, it was considered a fail (NG).

[0118] As shown in Tables 1 and 2, the laminates of Comparative Examples 1 and 2 had poor flame retardancy and failed the test, whereas the laminates of Examples 1 to 8 according to the present invention had excellent flame retardancy and also had sufficiently excellent impact resistance.

[0119] Examples 9 and 10 A two-layer flat laminate having a flame-retardant / electromagnetic wave shielding layer and a fiber-reinforced resin layer was obtained in the same manner as in Example 1, except that the raw materials and compounding ratios were as shown in Table 3.

[0120] The following tensile strength, tensile modulus, flexural strength, flexural modulus, electromagnetic wave shielding property, and the above-mentioned Charpy impact strength were measured for the flat laminates and single-layer molded articles obtained in Examples 9 and 10. The results are shown in Table 3.

[0121] (3) Mechanical properties: tensile strength and tensile modulus Dumbbell test pieces (JIS K 7161-2 Type 1BA) were prepared by cutting from the flat laminates and single-layer molded articles obtained in Examples 9 and 10. The tensile strength and tensile modulus of the prepared test pieces were measured using a tensile tester AG-20kNXDPlus (manufactured by Shimadzu Corporation). The results are shown in Table 3. The tensile test was carried out under the following measurement conditions: test temperature 23°C, tensile speed 2 mm / min, and gauge length 25 mm. Measurements of tensile strength and tensile modulus were performed in accordance with JIS K7161. A higher tensile strength value indicates a greater force required to break the test piece in tension mode. A higher tensile modulus value indicates a greater hardness of the test piece in tension mode.

[0122] (4) Mechanical properties: flexural strength and flexural modulus Strip test pieces (dimensions: 80 mm × 10 mm × 2.5 mmt) were cut from the flat laminates and single-layer molded articles obtained in Examples 9 and 10. The flexural strength and flexural modulus of the test pieces were measured using a bending tester AG-1kNX plus (manufactured by Shimadzu Corporation). The results are shown in Table 3. The measurement conditions for the bending test were a test temperature of 23°C, a bending speed of 2 mm / min, and a span distance of 64 mm. Measurements of flexural strength and flexural modulus were performed in accordance with JIS K7171. A higher flexural strength value indicates a greater force required to break the test piece in bending mode. A higher tensile modulus value indicates a greater hardness of the test piece in bending mode.

[0123] (6) Electromagnetic wave shielding evaluation The electromagnetic wave shielding performance (dB) of the flat laminates and molded articles (13 cm×10 cm) obtained in Examples 9 and 10 was quantitatively evaluated by the KEC method. The KEC method is a method for measuring electromagnetic shielding performance in the near field, developed by the KEC Kansai Electronics Industry Development Center, a general incorporated association. The electromagnetic shielding performance quantified by the KEC method is expressed as the difference in receiving strength between when a sample is sandwiched and when no sample is sandwiched. The measurement equipment used was an electric field shielding effectiveness evaluation device from the Kansai Electronics Industry Promotion Center (KEC), a general incorporated association. Table 3 shows the measured values ​​when the measurement frequencies were set to 100 kHz, 10 MHz, and 1 GHz. As shown in Table 3, the flat laminates of Examples 9 and 10 can be imparted with electromagnetic wave shielding properties without reducing flame retardancy. Just to be clear, flat laminates that do not contain components that block electromagnetic waves normally have low electromagnetic wave shielding properties, with 0 dB at frequencies of 100 kHz, 10 MHz, and 1 GHz.

[0124] [Table 3]

[0125] (5) Flame retardancy (burner test) The flat plate laminates obtained in Examples 1 to 6, 9, and 10 were heated at the center of the flat plate on the flame-retardant layer side for 5 minutes with a 1000°C flame from a Bunsen burner. The condition was then visually observed and evaluated according to the following evaluation criteria. The results are shown in Table 4. The burner test is a much more stringent test than the UL94 5V flame retardancy test, and an NG rating does not necessarily mean low flame retardancy. A pass result in the UL94 5V test indicates excellent flame retardancy, and a pass result in the burner test indicates particularly excellent flame retardancy.

[0126] <Evaluation criteria> OK: No holes were found in the flat laminate. NG: Holes were found in the flat laminate.

[0127] [Table 4]

Claims

1. A flame-retardant layer and a fiber-reinforced resin layer are provided. the flame-retardant layer contains a thermoplastic resin in an amount of 20% by mass to 80% by mass, based on the total mass of the flame-retardant layer, and at least one flame retardant selected from the group consisting of phosphorus-based flame retardants, bromine-based flame retardants, and inorganic hydrate-based flame retardants in an amount of 20% by mass to 80% by mass, based on the total mass of the flame-retardant layer (the total content of the thermoplastic resin and the flame retardant in the flame-retardant layer is in the range of 40 to 100% by mass), and the content of reinforcing fibers is 0% by mass to 20% by mass, based on the total mass of the flame-retardant layer (the total content of the thermoplastic resin, the flame retardant, and the reinforcing fibers in the flame-retardant layer is in the range of 40 to 100% by mass); The fiber reinforced resin layer contains 30% by mass to 90% by mass of a thermoplastic resin with respect to the total mass of the fiber reinforced resin layer, and 10% by mass to 70% by mass of reinforcing fibers with respect to the total mass of the fiber reinforced resin layer (the total content of the thermoplastic resin and the reinforcing fibers in the fiber reinforced resin layer is in the range of 40 to 100% by mass). A laminate.

2. The laminate according to claim 1 , wherein the content of the reinforcing fibers contained in the fiber-reinforced resin layer is at least 10% by mass greater than the content of the reinforcing fibers contained in the flame-retardant layer.

3. 2. The laminate according to claim 1, wherein the content of at least one flame retardant selected from the group consisting of phosphorus-based flame retardants, bromine-based flame retardants, and inorganic hydrate-based flame retardants in the fiber-reinforced resin layer is 0% by mass or more and less than 20% by mass with respect to the total mass of the fiber-reinforced resin layer.

4. the flame-retardant layer contains the flame retardant in an amount of 40% by mass to 80% by mass relative to the total mass of the flame-retardant layer; The fiber-reinforced resin layer contains 40% by mass to 60% by mass of the reinforcing fibers relative to the total mass of the fiber-reinforced resin layer, and the content of at least one flame retardant selected from the group consisting of phosphorus-based flame retardants, bromine-based flame retardants, and inorganic hydrate-based flame retardants is 0% by mass to 10% by mass relative to the total mass of the fiber-reinforced resin layer. The laminate according to claim 1.

5. The laminate according to claim 1 , wherein the fiber-reinforced resin layer contains, as the thermoplastic resin, at least one resin selected from the group consisting of polypropylene resin and polyamide resin.

6. The laminate according to claim 1 , wherein the reinforcing fibers include at least one type of fiber selected from the group consisting of carbon fibers and glass fibers.

7. The flame-retardant layer contains at least one of carbon nanotubes, carbon black, graphite, graphene, and graphite as an electromagnetic wave shielding filler, The laminate according to claim 1, wherein the content of the electromagnetic wave shielding filler is 0.1% by mass to 20% by mass relative to the total mass of the flame-retardant layer.

8. The laminate according to claim 1, wherein the fiber reinforced resin layer has a thickness of 0.5 to 30 mm.

9. A battery case for a non-aqueous electrolyte secondary battery, comprising the laminate according to any one of claims 1 to 8.

10. 10. The battery case for a non-aqueous electrolyte secondary battery according to claim 9, wherein the flame-retardant layer of the laminate is disposed on the inside of the battery case.

11. 10. The battery case for a non-aqueous electrolyte secondary battery according to claim 9, wherein the flame-retardant layers of the laminate are disposed on both the inside and outside of the battery case.

12. Further provided with an electromagnetic wave shielding layer, the electromagnetic wave shielding layer includes a binder resin and at least one electromagnetic wave shielding filler selected from carbon nanotubes, carbon black, graphite, graphene, and graphite; 10. The battery case for a non-aqueous electrolyte secondary battery according to claim 9, wherein the content of the electromagnetic wave shielding filler is 0.1% by mass or more and less than 5.0% by mass with respect to the total solid content of the electromagnetic wave shielding layer.

13. A battery for a non-aqueous electrolyte secondary battery, comprising the battery case for a non-aqueous electrolyte secondary battery according to claim 9 .

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