Fire-resistant urethane foam for battery and battery

Abstract

To provide a urethane foam that can quickly extinguish a fire caused by a sudden temperature rise in a battery cell, and has excellent conformability to an object to be protected.SOLUTION: According to the present invention, there is provided a fire-resistant urethane foam for a battery, which includes 10 to 400 parts by mass of a radical generator relative to 100 parts by mass of a urethane compound.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fire-resistant urethane foam for a battery and a battery. [Background technology]

[0002] In various types of batteries, such as lithium batteries, internal short circuits or the like can cause thermal runaway in battery cells, resulting in fires, smoke, and other problems. To mitigate the problems caused by such thermal runaway, attempts have been made to use protective materials, such as fireproofing materials or heat insulating layers, around battery cells. Such protective materials are expected to make it difficult for heat from high-temperature battery cells to propagate to other battery cells and the housing that houses the battery cells.

[0003] As a fire-resistant material, for example, there is fire-resistant urethane foam, which is expected to be flexible because it is in foam form, and a method for producing urethane foam by blending a phosphorus compound or a bromine compound as a flame retardant is known (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2023-109641 [Patent Document 2] Patent Publication No. 2023-121573 Summary of the Invention [Problem to be solved by the invention]

[0005] However, although these technologies provide a certain degree of flame retardancy, they do not provide sufficient fire extinguishing performance in a short period of time, which is necessary in the event of a fire in a battery.

[0006] Therefore, the present invention provides a urethane foam that can extinguish fires caused by sudden temperature rises in battery cells in a short time and has excellent conformability to the object to be protected. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved by using a urethane foam made of a composition with a specific blend, which has led to the completion of the present invention.

[0008] That is, according to the present invention, the following inventions are provided. [1] A fire-resistant urethane foam for batteries, comprising 10 to 400 parts by mass of a radical generator per 100 parts by mass of a urethane compound. [2] A test piece made of the fire-resistant urethane foam for batteries, measuring 30 mm in length, 30 mm in width, and 10 mm in thickness, is heated at 700°C for 20 minutes, and then subjected to a three-point bending test at a compression rate of 50 mm / min. The test piece has a breaking strength of 0.5 N or more. [3] The fire-resistant urethane foam for batteries according to [1] or [2], wherein the urethane compound contains a urethane prepolymer or contains a structure derived from a urethane prepolymer. [4] The fire-resistant urethane foam for batteries according to any one of [1] to [3], wherein the radical generator contains a carbonate. [5] A battery comprising the fire-resistant urethane foam for batteries according to any one of [1] to [4]. [Effects of the Invention]

[0009] The present invention provides a urethane foam that can quickly extinguish fires caused by sudden temperature rises in batteries and has excellent conformability to the object being protected. Such a urethane foam has a moderate softness and can be used as a foam protective material with excellent fire-extinguishing properties that can conform to the shape of a cylindrical battery cell, for example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Below, we will explain in detail the form for implementing the present invention (hereinafter referred to as the ``present embodiment''), but the present invention is not limited to this and various modifications are possible within the scope of the gist of the present invention.

[0011] 1. Fire-resistant urethane foam A urethane foam according to one embodiment of the present invention is a foamed product formed from a composition containing a urethane compound and a radical generator. Such urethane foam has excellent fire extinguishing properties and deformability, and can be used, for example, as a protective material for batteries (particularly battery cells, etc.). The urethane foam according to one embodiment of the present invention can be used as a fire-resistant urethane foam for batteries.

[0012] <Urethane compounds> The urethane compound is a compound having a urethane bond. The urethane compound preferably forms a urethane foam (a foamed product) together with an additive such as a radical generator. The urethane foam can be obtained, for example, by reacting a urethane raw material with a blowing agent. For example, carbon dioxide is generated by reacting the isocyanate group of the urethane raw material with water, which causes foaming to occur, resulting in the urethane foam. The urethane foam preferably has an expansion ratio of 2 to 20 times and a density of 120 to 500 kg / m. 3 is.

[0013] The urethane raw material includes an isocyanate compound. The urethane compound includes an isocyanate compound or includes a structure derived from an isocyanate compound. The urethane compound preferably includes a urethane prepolymer or includes a structure derived from a urethane prepolymer.

[0014] The urethane foam may contain 20 to 91% by mass of a urethane compound, preferably 25 to 71% by mass, and more preferably 33 to 59% by mass. When this range is satisfied, the urethane foam has a suitable softness while retarding combustion. Specific examples of the urethane compound content include 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, and 91% by mass, and may fall within a range between any two of the values ​​exemplified here.

[0015] <Isocyanate compounds> The isocyanate compound is, for example, a compound having two or more isocyanate groups. The isocyanate compound includes one or more compounds selected from the group consisting of polyisocyanates having two or more isocyanate groups and compounds (urethane prepolymers) which are polymers obtained by reacting a polyol with an excess of polyisocyanate and have isocyanate groups at the molecular terminals.

[0016] The urethane raw material may contain a polyol in addition to an isocyanate compound. The urethane raw material may contain, for example, a polyisocyanate and a polyol. When the urethane raw material contains multiple components, some or all of the components may be mixed in the reaction system.

[0017] When polyisocyanate and polyol are added as urethane raw materials, for example, 10 to 200 parts by mass of polyol can be added relative to 100 parts by mass of polyisocyanate, and preferably 50 to 150 parts by mass of polyol can be added. Specific examples of the amount of polyol added relative to 100 parts by mass of polyisocyanate include 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, and 200 parts by mass, and may be within a range between any two of the values ​​exemplified here.

[0018] <Polyisocyanate> Examples of polyisocyanates include aromatic isocyanates, alicyclic isocyanates, and aliphatic isocyanates.

[0019] Examples of aromatic isocyanates include phenylene diisocyanate, tolylene diisocyanate (e.g., toluene-2,4-diisocyanate), xylylene diisocyanate, diphenylmethane diisocyanate (bis(4-isocyanatophenyl)methane), dimethyldiphenylmethane diisocyanate, triphenylmethane triisocyanate, naphthalene diisocyanate, and polymethylene polyphenyl polyisocyanate.

[0020] Examples of alicyclic isocyanates include cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and dimethyldicyclohexylmethane diisocyanate.

[0021] Examples of the aliphatic isocyanate include methylene diisocyanate, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate.

[0022] One or more types of polyisocyanates can be used.

[0023] <Urethane prepolymer> Urethane prepolymers are polymers obtained by reacting polyol with excess polyisocyanate, and are compounds with isocyanate groups at the molecular terminals. Urethane prepolymers include polyether-based and polyester-based urethane prepolymers, and examples of polyether-based prepolymers include prepolymers obtained by reacting tolylene diisocyanate with polyol.

[0024] <Polyol> Examples of polyols include polylactone polyols, polycarbonate polyols, aromatic polyols, alicyclic polyols, aliphatic polyols, polyester polyols, polymer polyols, and polyether polyols.

[0025] Examples of polylactone polyols include polypropiolactone glycol, polycaprolactone glycol, and polyvalerolactone glycol.

[0026] Examples of polycarbonate polyols include polyols obtained by dealcoholization reaction of a hydroxyl group-containing compound such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, octanediol, or nonanediol with diethylene carbonate or dipropylene carbonate.

[0027] Examples of aromatic polyols include bisphenol A, bisphenol F, phenol novolac, and cresol novolac.

[0028] Examples of alicyclic polyols include cyclohexanediol, methylcyclohexanediol, isophoronediol, dicyclohexylmethanediol, and dimethyldicyclohexylmethanediol.

[0029] Examples of the aliphatic polyol include ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol.

[0030] Examples of polyester polyols include polymers obtained by dehydration condensation of polybasic acids and polyhydric alcohols, polymers obtained by ring-opening polymerization of lactones such as ε-caprolactone and α-methyl-ε-caprolactone, and condensates of hydroxycarboxylic acids and the above-mentioned polyhydric alcohols.

[0031] Examples of polymer polyols include polymers obtained by graft polymerizing an ethylenically unsaturated compound such as acrylonitrile, styrene, methyl acrylate, or methacrylate onto an aromatic polyol, an alicyclic polyol, an aliphatic polyol, or a polyester polyol; polybutadiene polyol; modified polyols of polyhydric alcohols; and hydrogenated products thereof.

[0032] Examples of polyether polyols include polymers obtained by ring-opening polymerization of at least one alkylene oxide such as ethylene oxide, propylene oxide, or tetrahydrofuran in the presence of at least one low-molecular-weight active hydrogen compound having two or more active hydrogens.

[0033] One or more types of polyols can be used.

[0034] <Foaming agent> The blowing agent promotes foaming of the urethane. Examples of the blowing agent include hydrofluoroolefins having 3 or 4 carbon atoms, such as trans-1-chloro-3,3,3-trifluoropropene, and water. Among these, water is preferred because it dissolves the radical generator easily.

[0035] <Radical generator> The radical generator is a component that generates an aerosol (radicals) by the thermal energy generated by the combustion of a urethane compound, etc. Examples of the radical generator include potassium salt-based radical generators and sodium salt-based radical generators.

[0036] Examples of potassium salt radical generators include potassium acetate, potassium propionate, monopotassium citrate, dipotassium citrate, tripotassium citrate, monopotassium trihydrogen ethylenediaminetetraacetate, dipotassium dihydrogen ethylenediaminetetraacetate, tripotassium monohydrogen ethylenediaminetetraacetate, tetrapotassium ethylenediaminetetraacetate, potassium hydrogen phthalate, dipotassium phthalate, potassium hydrogen oxalate, dipotassium oxalate, potassium hydrogen carbonate, and potassium carbonate.

[0037] Examples of sodium salt radical generators include sodium acetate, sodium citrate, and sodium bicarbonate.

[0038] Among these, from the viewpoint of fire extinguishing properties, carbonates such as potassium hydrogen carbonate, potassium carbonate, sodium hydrogen carbonate, etc. are preferred. These radical generators may be used alone or in combination of two or more.

[0039] The content of the radical generator is 10 to 400 parts by mass, preferably 40 to 300 parts by mass, and more preferably 70 to 200 parts by mass, per 100 parts by mass of the urethane compound. If the content of the radical generator is too low, fire extinguishing properties will be poor. If the content of the radical generator is too high, the urethane foam will become hard. The content of the radical generator is, for example, 10, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, or 400 parts by mass per 100 parts by mass of the urethane compound, and may be within a range between any two of the values ​​exemplified here.

[0040] Urethane foams can also contain other additives as needed, provided that their properties are not impaired, such as inorganic compounds other than radical generators, surfactants, foam stabilizers, catalysts, blowing agents, flame retardants, stabilizers, UV absorbers, antioxidants, pigments, etc.

[0041] Examples of inorganic compounds other than radical generators include metal oxides such as alumina, aluminosilicate, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, and ferrites; metal hydroxides such as aluminum hydroxide, calcium hydroxide, magnesium hydroxide, and aluminum hydroxide; smectite clays such as bentonite, montmorillonite, and hectorite, fibrous clays such as palygorskite, sericite (sericite), illite, glauconite, chlorite, talc, zeolite (zeolite), beidellite, nontronite, saponite, hectorite, sauconite, stevensite, cristopalite, smectite, kaolin, and hydrotalcite; metal carbonates such as basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, strontium carbonate, and barium carbonate; and glass fibers (E-glass fibers). , C-glass fiber, S-glass fiber, D-glass fiber), rock wool, ceramic fibers (silica alumina fiber, alumina fiber, silica fiber), zirconia fiber, carbon fiber, bulk alkaline earth silicate fiber, gypsum fiber, carbon fiber, metal fiber, slag fiber, basalt fiber and other fibrous inorganic compounds; calcium salts such as calcium sulfate and calcium silicate, glass beads, silica-based balun, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon balun, charcoal powder, various metal powders, potassium titanate, magnesium sulfate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, zinc borate, various magnetic powders, fly ash, inorganic hollow fillers, perlite, obsidian, perlite, rosin, diatomaceous earth, dewatered sludge, boron, sodium tetraborate hydrate (borax), silica, titanium oxide, inorganic oxidizing agents, phosphate compounds, thermally expandable graphite, vermiculite, etc. These inorganic compounds may be used alone or in combination of two or more.

[0042] The content of the inorganic compound other than the radical generator is 0 to 400 parts by mass, preferably 0 to 200 parts by mass, and more preferably 0 to 100 parts by mass, relative to 100 parts by mass of the urethane compound.

[0043] <Inorganic oxidizing agents> The inorganic oxidizing agent is a component that burns together with the liquid organic compound to generate thermal energy. Examples of the inorganic oxidizing agent include potassium chlorate, sodium chlorate, strontium chlorate, ammonium chlorate, magnesium chlorate, and potassium perchlorate. Among these, one type may be used alone, or two or more types may be used in combination.

[0044] <Phosphate-based inorganic compounds> In addition to phosphoric acid compounds, phosphorous acid compounds include phosphorous acid compounds, hypophosphorous acid compounds, metaphosphate compounds, pyrophosphate compounds, and polyphosphate compounds.

[0045] Examples of phosphate compounds include monoaluminum phosphate, monosodium phosphate, monopotassium phosphate, monocalcium phosphate, monozinc phosphate, dialuminum phosphate, disodium phosphate, dipotassium phosphate, dicalcium phosphate, dizinc phosphate, trialuminum phosphate, trisodium phosphate, tripotassium phosphate, tricalcium phosphate, trizinc phosphate, trimagnesium phosphate, monoammonium phosphate, diammonium phosphate, tricalcium phosphate, and aluminum phosphate.

[0046] Examples of the phosphite compounds include aluminum phosphite, aluminum hydrogen phosphite, sodium phosphite, potassium phosphite, calcium phosphite, and zinc phosphite.

[0047] Examples of hypophosphite compounds include aluminum hypophosphite, sodium hypophosphite, potassium hypophosphite, calcium hypophosphite, and zinc hypophosphite.

[0048] Examples of metaphosphate compounds include aluminum metaphosphate, sodium metaphosphate, potassium metaphosphate, calcium metaphosphate, zinc metaphosphate, and sodium hexametaphosphate.

[0049] An example of the pyrophosphate compound is sodium pyrophosphate.

[0050] Examples of polyphosphate compounds include ammonium polyphosphate, melamine-modified ammonium polyphosphate, sodium tripolyphosphate, sodium pentapolyphosphate, sodium tetrapolyphosphate, and potassium tripolyphosphate.

[0051] From the viewpoint of shape stability at high temperatures, aluminum hydrogen phosphite, ammonium polyphosphate, etc. are preferred as the phosphoric acid-based inorganic compound.

[0052] The content of the phosphoric acid-based inorganic compound is preferably 5 to 140 parts by mass per 100 parts by mass of the urethane compound. This range ensures that the urethane foam does not lose its shape even at high temperatures and also achieves flame retardancy.

[0053] Furthermore, the inorganic compound other than the radical generator preferably contains a metal hydroxide, which can enhance fire extinguishing properties.

[0054] <Thermal Expandable Graphite> Thermally expandable graphite is a crystalline compound that is obtained by surface-treating graphite powder, such as natural graphite or pyrolytic graphite, with an inorganic acid, such as sulfuric acid or nitric acid, and a strong oxidizing agent, such as concentrated nitric acid or permanganate, and that maintains a graphite layer structure. When exposed to a temperature equal to or higher than the expansion initiation temperature (approximately 200°C) under normal pressure, it thermally expands by 100 times or more. Note that the graphite powder, such as natural graphite or pyrolytic graphite, may be subjected to a deoxidation treatment or further neutralization treatment.

[0055] The content of the thermally expandable graphite is, for example, 3 to 100 parts by mass, preferably 5 to 75 parts by mass, and more preferably 10 to 50 parts by mass, relative to 100 parts by mass of the urethane compound.Specific examples of the content of the thermally expandable graphite relative to 100 parts by mass of the liquid organic compound include 0, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 parts by mass, and may be within a range between any two of the numerical values ​​exemplified here.

[0056] <Characteristics of urethane foam composition> When a urethane foam is prepared into a test piece measuring 30 mm long x 30 mm wide x 10 mm thick, the Shore E hardness of the 30 mm long x 30 mm wide surface measured in accordance with JIS K6253 under a load of 1 kg at 21°C is preferably less than 25, more preferably less than 20, and even more preferably less than 15. There is no particular restriction on the lower limit of the Shore E hardness, but it is, for example, 1 or more. When the Shore E hardness is in this range, the urethane foam has flexibility (deformability) and excellent conformability to the object to be protected.

[0057] When a urethane foam is prepared into a test piece measuring 30 mm long x 30 mm wide x 10 mm thick, the test piece is heated at 700°C for 20 minutes, and then broken using a three-point bending test jig at a compression rate of 50 mm / min. The breaking strength is preferably 0.5 N or more, more preferably 1.5 N or more, and even more preferably 2.5 N or more. There is no particular upper limit to the breaking strength, but it is, for example, 10 N or less. When the breaking strength is in this range, the shape stability at high temperatures is excellent, making it suitable for use as a protective material for batteries.

[0058] <Manufacturing method> A method for producing a urethane foam according to one embodiment of the present invention includes, for example, a blending step of blending a urethane raw material containing an isocyanate compound with a mixture (e.g., a mixed liquid such as an aqueous solution) containing a radical generator and a blowing agent. In the blending step, foam molding is performed by blending accompanied by addition, stirring, etc. The content of the blowing agent (e.g., water) contained in the mixture is preferably 10 parts by mass or more, more preferably 50 to 500 parts by mass, and even more preferably 80 to 200 parts by mass per 100 parts by mass of the isocyanate compound. The mixture containing the radical generator and the blowing agent may also contain other additives such as inorganic compounds other than the radical generator.

[0059] Furthermore, when water is used as a blowing agent, the method for producing a urethane foam composition may include a drying step of drying the urethane foam (foam) after expansion molding. The drying step may be carried out at a temperature of, for example, 50 to 100°C (for example, 80°C).

[0060] <Other embodiments> A battery according to another embodiment of the present invention includes a component made of the above-described urethane foam. The battery typically has at least one battery cell, to which the above-described urethane foam composition is attached as a protective material, fireproof material, or other component. The urethane foam composition is typically attached to the surface of the battery cell so as to cover a part or the entire surface of the battery cell. The battery may have one battery cell or two or more battery cells. The battery and battery cells may have various shapes.

[0061] The urethane foam provided in the battery can be arranged so as to cover the battery with, for example, a sheet-shaped urethane foam. The urethane foam provided in the battery can also be molded to match the shape of the battery or battery cell to be covered. The molding can be performed using a mold during foaming, or by processing such as cutting after foaming.

[0062] The urethane foam provided in the battery can be arranged on the battery or battery cell it covers in various ways. For example, the urethane foam may be placed directly and fixed from the outside, or it may be fixed by placing a fixing member such as adhesive or double-sided tape between the urethane foam and the battery (cell).

[0063] In addition, examples of battery cells include secondary batteries such as lithium ion batteries, lithium ion polymer batteries, nickel-metal hydride batteries, lithium-sulfur batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, sodium-sulfur batteries, lead-acid batteries, and air batteries, but are not limited to these.

[0064] Batteries are used in, but not limited to, small electronic devices such as mobile phones and smart phones, laptops, automobiles, power tools, and the like. [Example]

[0065] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following description, parts and percentages are based on mass.

[0066] <Preparation of urethane foam composition> (A: When polyisocyanate is used as the isocyanate compound [Examples 1 and 2]) A radical generator mixed aqueous solution was prepared by blending water (blowing agent) with the radical generator in the amounts shown in the table. Polyisocyanate and polyol were added to this aqueous solution, stirred, and poured into a cylindrical mold 10 cm in diameter x 15 cm in height to form a foam. The mixture was then left in an oven at 80°C for 3 days, along with the mold, to evaporate the water and obtain a sample of the urethane foam composition. The amount of water was 100 parts by mass per 50 parts by mass of polyisocyanate.

[0067] (B: When a urethane prepolymer was used as the isocyanate compound [Examples 3 to 12, Comparative Examples 1 to 4]) A radical generator or flame retardant mixed aqueous solution was prepared by blending water (blowing agent) with the radical generator or flame retardant in the amounts shown in the table. The urethane prepolymer was added to this aqueous solution and stirred. The mixture was then poured into a cylindrical mold measuring 10 cm in diameter and 15 cm in height to form a foam. The mixture, along with the mold, was then left in an oven at 80°C for three days to evaporate the water, yielding a sample of the urethane foam composition. The amount of water was 200 parts by weight per 100 parts by weight of the urethane prepolymer.

[0068] The materials used in the examples and comparative examples are shown below.

[0069] <Polyisocyanate> Toluene-2,4-diisocyanate: Cosmonate T100 manufactured by Mitsui Chemicals, Inc. Bis(4-isocyanatophenyl)methane: "Cosmonate PH" manufactured by Mitsui Chemicals, Inc.

[0070] <Polyol> Polyether polyol: Sannix FA-195 manufactured by Sanyo Chemical Industries, Ltd.

[0071] <Urethane prepolymer> Polyether: Mitsui Chemicals "Hypren EGH-401"

[0072] <Radical generator> Potassium bicarbonate: Hayashi Pure Chemical Industries, Ltd. Potassium carbonate: Hayashi Pure Chemical Industries, Ltd. Sodium bicarbonate: Hayashi Pure Chemical Industries, Ltd. Tripotassium citrate: manufactured by Fuso Chemical Co., Ltd.

[0073] <Flame retardant> Phosphate ester flame retardant tris(β-chloropropyl)phosphate: "TMCPP" manufactured by Daihachi Chemical Industry Co., Ltd. Brominated flame retardant: Tetrabromobisphenol A bis(2,3-dibromo-2-methylpropyl) ether (Daiichi Pharmaceutical Co., Ltd. "Pyroguard SR-130")

[0074] <Foaming agent> ·water

[0075] In the examples and comparative examples, the following properties were evaluated and are summarized in the table below. The methods for measuring each property are shown below.

[0076] <Following ability (hardness)> The original samples of the Examples and Comparative Examples were cut into test pieces measuring 30 mm in length, 30 mm in width, and 10 mm in thickness, and the Shore E hardness of the 30 mm in length and 30 mm in width surface was measured under a load of 1 kg in an environment of 21° C. in accordance with JIS K6253. Then, based on the measured values, the hardness was evaluated according to the following criteria. [Evaluation criteria] ⊚: Shore E hardness is less than 15. ◯: Shore E hardness is 15 or more and less than 20. △: Shore E hardness is 20 or more and less than 25. ×: Shore E hardness is 25 or more.

[0077] <Fire extinguishing properties> A test specimen was created by placing a 2mm thick sheet-like test piece around a laminated lithium-ion battery used in smartphones so that it completely covered the battery.The test specimen was then placed on a hot plate set at 300°C and the time from the release of fire to the extinguishing of the fire was evaluated.A shorter fire extinguishing time indicates better fire extinguishing performance. ◎: Extinguishing time is less than 3 seconds 〇: Fire extinguishing time is between 3 and 6 seconds △: Extinguishing time is between 6 and 10 seconds ×: Fire extinguishing time is 10 seconds or more

[0078] <Shape stability at high temperatures> The raw samples of the examples and comparative examples were cut into test pieces measuring 30 mm long x 30 mm wide x 10 mm thick. The test pieces were heated at 700°C for 20 minutes, and then the fracture strength was measured using a three-point bending test jig (upper pushing side tip R1 mm and width 80 mm, lower two-point support side R1 mm, width 80 mm, distance between supports 20 mm) at a compression rate of 50 mm / min. The higher the fracture strength, the higher the strength at high temperatures. Based on the fracture strength, the shape stability at high temperatures was evaluated according to the following criteria. [Evaluation criteria] ◎: Breaking strength is 2.5 [N] or more ○: Breaking strength is 1.5 [N] or more and less than 2.5 [N] △: Breaking strength is 0.5 [N] or more and less than 1.5 [N] ×: Breaking strength is less than 0.5 [N]

[0079] [Table 1]

[0080] [Table 2]

Claims

1. A fire-resistant urethane foam for batteries, comprising 10 to 400 parts by mass of a radical generator relative to 100 parts by mass of a urethane compound.

2. A test piece made of the fire-resistant urethane foam for batteries, measuring 30 mm in length, 30 mm in width, and 10 mm in thickness, is heated at 700°C for 20 minutes, and then the test piece is broken using a three-point bending test jig at a compression rate of 50 mm / min, and the breaking strength is 0.5 N or more.

3. The fire-resistant urethane foam for batteries according to claim 1 , wherein the urethane compound comprises a urethane prepolymer or comprises a structure derived from a urethane prepolymer.

4. The fire-resistant urethane foam for batteries according to claim 1 or 2, wherein the radical generator comprises a carbonate.

5. A battery comprising the fire-resistant urethane foam for batteries according to claim 1 or 2.

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