Flame-retardant coating composition and sheet for preventing battery thermal runaway comprising same

Abstract

The present invention relates to a flame-retardant coating composition comprising: 3-40 parts by weight of solid content of a water-soluble resin; 40-80 parts by weight of solid content of a flame retardant; 0.1-10 parts by weight of solid content of an additive; and 5-30 parts by weight of a solvent, wherein the flame retardant comprises 0.1-25 parts by weight of solid content of a phosphorus-based flame retardant and 20-45 parts by weight of solid content of a metal hydroxide-based flame retardant.

Description

Flame retardant coating composition and sheet for preventing battery thermal runaway comprising the same

[0001] The present invention relates to a flame retardant coating composition, and more particularly, to a flame retardant coating composition applicable to a sheet for preventing battery thermal runaway using various coating methods.

[0002] Generally, flame-retardant coatings are compositions that delay ignition and prevent the spread of combustion in combustible materials and prevent deterioration in non-combustible materials in the event of a fire. Specifically, flame-retardant coatings protect combustible or non-combustible materials from heat or flames and are applied to the surfaces of various substrates, such as textiles. In particular, flame-retardant coatings must exhibit excellent adhesion to the substrate, even when particles are present on the substrate's surface.

[0003] Meanwhile, demand for large-capacity battery modules has been increasing recently. These battery modules are facing issues with thermal runaway damage.

[0004] To prevent thermal runaway in battery modules, thermal runaway prevention sheets are placed between cells within the module. Since most of these thermal runaway prevention sheets are made of fiber, a flame-retardant coating composition with excellent flame retardancy and adhesion to fiber materials is required.

[0005] [Prior Art Literature]

[0006] (Patent Document 1) Republic of Korea Patent No. 10-1729075 (April 17, 2017)

[0007] One object of the present invention is to provide a flame retardant coating composition having a variety of viscosities from high to low and excellent adhesion to a fiber material.

[0008] The present invention provides a flame-retardant coating composition comprising 3 to 40 parts by weight of a water-soluble resin in solid content, 40 to 80 parts by weight of a flame retardant in solid content, 0.1 to 10 parts by weight of an additive in solid content, and 5 to 30 parts by weight of a solvent, wherein the flame retardant comprises 0.1 to 25 parts by weight of a phosphorus-based flame retardant in solid content and 20 to 45 parts by weight of a metal hydroxide-based flame retardant in solid content.

[0009] The flame retardant coating composition according to the present invention can be used at various viscosities from high viscosity (e.g., 10,000 to 30,000 cPs) to low viscosity (e.g., 100 cPs), has excellent adhesion to fiber materials, and can be used in various coating methods.

[0010] Hereinafter, various embodiments of the present invention will be described in detail.

[0011] The “particle size (D50)” used herein is measured by a conventional method known in the art, and can be measured, for example, by laser light scattering (LLS).

[0012] The present invention provides, in one aspect, a flame-retardant coating composition. Specifically, the present invention provides a flame-retardant coating composition applicable to a sheet for preventing battery thermal runaway using various coating methods.

[0013] In one specific example, the flame retardant coating composition of the present invention comprises a water-soluble resin, a flame retardant, an additive, and a solvent. Specifically, the flame retardant coating composition of the present invention comprises 3 to 40 parts by weight of the water-soluble resin in solid content, 40 to 80 parts by weight of the flame retardant in solid content, 0.1 to 10 parts by weight of the additive in solid content, and 5 to 30 parts by weight of the solvent.

[0014] In this specification, except for the solvent, the content of each component is based on the solid content. For example, the flame-retardant coating composition of the present invention contains 3 to 40 parts by weight of a water-soluble resin based on the solid content of the water-soluble resin, 40 to 80 parts by weight of a flame retardant based on the solid content of the flame retardant, and 0.1 to 10 parts by weight of an additive based on the solid content of the additive.

[0015] Meanwhile, the flame retardant comprises 0.1 to 25 parts by weight of a solid content of a phosphorus-based flame retardant and 20 to 45 parts by weight of a solid content of a metal hydroxide-based flame retardant.

[0016] The water-soluble resin is a main resin that forms a coating film formed by the flame-retardant coating composition of the present invention. The flame-retardant coating composition of the present invention includes a water-dispersible resin to ensure excellent flame-retardant performance.

[0017] In one specific example, the water-soluble resin of the present invention includes at least one selected from the group consisting of ethylene vinylacetate (EVA) resin, polyvinylchloride resin, water-soluble acrylic resin, polyvinylacetate (PVAC) resin, polybutadiene resin, polyvinylidene chloride resin, and polyurethane (PU) resin.

[0018] When ethylene vinyl acetate resin is used as a water-soluble resin, it is effective because it has strong cohesiveness and can maintain the strength of the flame-retardant coating layer formed by the flame-retardant coating composition of the present invention at a certain level or higher.

[0019] The ethylene vinyl acetate resin of the present invention has a solid content of 98 wt% or more based on the total weight of the resin and a density of 400 to 550 kg / m. 3 , the particle size is 400 ㎛ or more, and the content of such particles is up to 4 wt%.

[0020] The water-soluble resin is included in the flame-retardant coating composition in an amount of 3 to 40 parts by weight, or 5 to 35 parts by weight, or 10 to 30 parts by weight, based on the solid content. If the amount of the water-soluble resin is less than 3 parts by weight, a coating film may not be formed, and if it exceeds 40 parts by weight, a problem of reduced flame retardancy may occur.

[0021] In one specific embodiment, the flame retardant coating composition of the present invention further comprises a thermoplastic resin. The thermoplastic resin serves to impart flexibility to the coating film.

[0022] The thermoplastic resin of the present invention includes at least one selected from the group consisting of polyvinyl alcohol, polyvinyl formal, polyvinyl butyral (PVB), polyethylene terephthalate, polycaprolactam, polyhexamethylene adipamide, polycarbonate, polycarbonate / ABS resin, polyacetal, polyphenylene sulfatadiene, polyurethane, and cellulose-based resins, and is preferably a polyvinyl butyral (PVB) resin, but is not limited thereto.

[0023] The thermoplastic resin is included in the flame retardant coating composition in an amount of from 0 to 20 parts by weight or from 5 to 15 parts by weight based on the solid content.

[0024] Flame retardants serve to impart flame retardant properties to the coating.

[0025] The flame retardant of the present invention includes a non-halogen flame retardant instead of a halogen flame retardant. In the case of a halogen flame retardant, when a fire occurs, a large amount of smoke and toxicity are generated and corrosive hydrogen halide gas is generated, which not only causes environmental problems but also reduces mechanical properties.

[0026] Therefore, in order to solve these problems, the present invention uses a non-halogen flame retardant, and in one specific example, the flame retardant of the present invention includes a phosphorus-based flame retardant and a metal hydroxide-based flame retardant.

[0027] The phosphorus-based flame retardant of the present invention imparts excellent flame retardancy to coatings in a solid-state reaction. Specifically, the phosphorus-based flame retardant of the present invention is a polymer that forms carbonaceous ash (char) upon thermal decomposition. This ash formation reduces combustible fuel and forms a thick barrier on the surface of combustible molecules, blocking heat and thus extinguishing fire.

[0028] This action occurs in the condensed phase, and phosphorus is an important condensed phase flame retardant. Phosphorus decomposes thermally to form phosphoric acid, which acts as a dehydration catalyst in combustible materials, increasing the amount of char. Notably, phosphorus (P)-based flame retardants are environmentally friendly materials that do not produce dioxins, a carcinogen.

[0029] In one specific example, the phosphorus flame retardant of the present invention comprises at least one selected from the group consisting of ammonium polyphosphate (APP), triphenyl phosphate (TPP), tricresyl phosphate (TCP), triethyl phosphate (TEP), isopropyl phenyl diphenyl phosphate, red phosphorus (CG-P), tris(2-chloroethyl)phosphate (TCEP), and resorcinol di phosphate (RDP).

[0030] The metal hydroxide-based flame retardant of the present invention does not volatilize under heat, but decomposes to release non-flammable gases such as water, carbon dioxide, sulfur dioxide, and hydrogen chloride, and produces water through thermal decomposition, thereby imparting a flame retardant effect to the coating. Furthermore, it prevents combustion through a cooling effect caused by heat absorption and the generated water.

[0031] In one specific example, the metal hydroxide-based flame retardant of the present invention includes at least one selected from the group consisting of aluminum hydroxide (Al(OH)3), calcium hydroxide (Ca(OH)2), and magnesium hydroxide (Mg(OH)2).

[0032] Metal hydroxide-based flame retardants can be used by mixing those having a large particle size of 10 ㎛ or more (e.g., 10 to 50 ㎛, or 10 to 30 ㎛) and those having a small particle size of 5 ㎛ or less (e.g., 2 to 5 ㎛).

[0033] When using a mixture of metal hydroxide-based flame retardants having different particle sizes, the metal hydroxide-based flame retardant with a smaller particle size can minimally penetrate into the interior of the flame-retardant composite sheet described below, whereas the metal hydroxide-based flame retardant with a larger particle size can be uniformly coated on the exterior of the flame-retardant composite sheet. Accordingly, a sheet for preventing battery thermal runaway, which includes a flame-retardant coating layer formed by coating the flame-retardant coating composition of the present invention on the upper or lower surface of the flame-retardant composite sheet, can have an excellent surface roughness (Ra) of 0.2 to 1.0 ㎛.

[0034] Meanwhile, when only metal hydroxide-based flame retardants having a particle size of 5 ㎛ or less (e.g., 2 to 5 ㎛) are used, the metal hydroxide-based flame retardants having small particle sizes may excessively penetrate into the flame retardant composite sheet, thereby increasing the rigidity of the sheet for preventing battery thermal runaway, which may reduce the buffering effect during battery charging and discharging, thereby shortening the lifespan of the battery.

[0035] In addition, when using a metal hydroxide-based flame retardant with a particle size of 1 ㎛ or less, there is a problem that it is difficult to apply due to poor dispersibility.

[0036] In one specific example, the flame retardant is included in the flame retardant coating composition in an amount of 40 to 80 parts by weight, 45 to 70 parts by weight, or 47 to 60 parts by weight based on the solid content. If the flame retardant content is less than 40 parts by weight, the coating film may burn upon initial ignition, and if it exceeds 80 parts by weight, the excessive amount included makes it difficult to form the coating film.

[0037] In one specific example, the flame retardant comprises 0.1 to 25 parts by weight or 1 to 20 parts by weight of a solid content of a phosphorus-based flame retardant, and 20 to 45 parts by weight or 25 to 40 parts by weight of a metal hydroxide-based flame retardant.

[0038] If the content of the phosphorus flame retardant is below the above range, the effect of providing flexibility to the sheet for preventing thermal runaway due to the phosphorus flame retardant is insufficient, and if it exceeds the above range, problems may occur in the appearance of the manufactured coating film.

[0039] While higher metal hydroxide flame retardant content significantly improves flame retardant properties, it can also release toxic gases, potentially posing a risk to human health. Therefore, metal hydroxide flame retardants are included in the minimum amount necessary to ensure non-combustibility.

[0040] In one specific example, the weight ratio of the phosphorus-based flame retardant and the metal hydroxide-based flame retardant is 1:1 to 1:30, or 1:2 to 1:25, based on solid content.

[0041] When the weight ratio of the phosphorus-based flame retardant and the metal hydroxide-based flame retardant is less than 1:1, the surface temperature of the coating film rises rapidly, making it difficult to delay ignition. On the other hand, when the weight ratio of the phosphorus-based flame retardant and the metal hydroxide-based flame retardant exceeds 1:30, it is difficult to disperse them within the flame-retardant coating composition, which hinders the uniformity of the coating film, and the bendability is poor, and the coating film drying time is fast, making it difficult to work in the coating process.

[0042] In one specific example, in the flame retardant coating composition of the present invention, the ratio (A or A':B) of the weight of the water-soluble resin (A), or the sum of the weight of the water-soluble resin and the weight of the thermoplastic resin (A'), and the weight of the flame retardant (B) is 1:1 to 1:10 or 1:2 to 1:8 on a solid basis.

[0043] Specifically, when the flame retardant coating composition of the present invention includes a water-soluble resin and does not include a thermoplastic resin, the ratio (A:B) of the weight of the water-soluble resin (A) and the weight of the flame retardant (B) is 1:1 to 1:10 or 1:2 to 1:8 based on the solid content.

[0044] Meanwhile, when the flame retardant coating composition of the present invention includes a water-soluble resin and a thermoplastic resin, the ratio (A':B) of the sum of the weight of the water-soluble resin and the weight of the thermoplastic resin (A') and the weight of the flame retardant (B) is 1:1 to 1:10 or 1:2 to 1:8 based on the solid content.

[0045] If the ratio (A or A':B) of the weight of the water-soluble resin (A), or the sum of the weights of the water-soluble resin and the thermoplastic resin (A') and the weight of the flame retardant (B) is less than 1:1, the time it takes for the coating film to ignite and burn completely is long, and there is a problem that the flame retardancy and non-combustibility characteristics are reduced. On the other hand, if the weight ratio (A or A':B) exceeds 1:10, the flame retardant ratio is high, making dispersion difficult and the uniformity of the coating film is deteriorated.

[0046] In one specific example, in the flame retardant coating composition of the present invention, the flame retardant further comprises 20 to 40 parts by weight or 25 to 35 parts by weight of the solid content of the filler.

[0047] In the flame retardant coating composition of the present invention, the ratio (A or A':C) of the weight of the water-soluble resin (A), or the sum of the weight of the water-soluble resin and the weight of the thermoplastic resin (A'), and the weight of the filler (C) is 1:1 to 1:7 or 1:1.2 to 1:4 based on the solid content.

[0048] If the above ratio (A or A':C) is below the above range, not only may the workability be reduced due to the tack of the coating film, but also the flame retardancy may be reduced. In addition, if the above ratio (A or A':C) exceeds the above range, the filler content is excessive, which increases the possibility of the filler being eluted from the coating film, and may cause cracks in the coating film due to insufficient flexibility and bendability.

[0049] In the present invention, the filler may be, for example, calcium carbonate, mica, kaolin, talc, etc., but is not limited thereto.

[0050] In one specific example, the additive comprises at least one selected from an aqueous dispersant and a pigment.

[0051] The additive is included in the flame retardant coating composition in an amount of 0.1 to 10 parts by weight based on the solid content.

[0052] The aqueous dispersant plays a role in improving the dispersibility of the flame retardant. The aqueous dispersant of the present invention may be non-silicone-based, and may be, for example, product names BYK-011, 012, 014, 015, 021, 022, 024, 037, 054T, 092, 093, 190, 40, 10, 326, 346, 347, 348, 349.

[0053] The water-based dispersant is included in the flame-retardant coating composition in an amount of 1 to 10 parts by weight based on the solid content.

[0054] Pigments play a role in imparting color to the coating. In the present invention, the pigments may be, for example, product names RAVEN 1200, MA100, MA600MJS, NEROX 1000, RAVEN1170, PRINTEX 200, DENKA BLACK, RAVEN 14, BLACK PEARL 1400, and RAVEN R900.

[0055] The pigment is included in the flame retardant coating composition in an amount of 0.1 to 5 parts by weight based on the solid content.

[0056] The solvent serves to control the viscosity of the flame retardant coating composition.

[0057] In the present invention, the solvent includes water. The solvent is preferably water such as deionized water or distilled water.

[0058] The solvent is included in the flame retardant coating composition in an amount of 5 to 30 parts by weight or 10 to 20 parts by weight.

[0059] In another aspect, the present invention provides a flame-retardant coating layer formed using the flame-retardant coating composition of the present invention. The flame-retardant coating layer of the present invention can be formed by applying the flame-retardant coating composition of the present invention to the upper or lower surface of a flame-retardant composite sheet comprising, for example, a fiber-reinforced core material and silica.

[0060] The flame retardant coating layer protects the flame retardant composite sheet from fire or heat, enhances the heat retardant effect, and can effectively block dust generated from the flame retardant composite sheet.

[0061] In another aspect, the present invention provides a sheet for preventing battery thermal runaway, comprising a flame-retardant composite sheet and a flame-retardant coating layer formed on the upper or lower surface of the flame-retardant composite sheet.

[0062] The flame retardant composite sheet comprises a fiber-reinforced core and silica. Specifically, the flame retardant composite sheet is manufactured by impregnating the fiber-reinforced core with an impregnating solution containing silica.

[0063] The fiber-reinforced core material comprises at least one fiber selected from polyester, polyacrylonitrile (PAN), oxidized polyacrylonitrile, non-carbonized heat-treated PAN, carbon, silica, polyaramid, polycarbonate, polyolefin, rayon, nylon, glass wool, high-density polyolefin, ceramic, acrylic, fluoropolymer, polyurethane, polyamide, and polyimide.

[0064] The impregnating liquid contains a solvent and silica.

[0065] The solvent included in the impregnating liquid is water, and may preferably be distilled water or deionized water.

[0066] Silica includes at least one selected from fumed silica, precipitated silica, silica glass, and optical fiber (silicon ester).

[0067] Below, various experimental examples of the present invention are described. However, these experimental examples are intended only to aid understanding of the present invention and are not intended to limit the scope of the present invention in any way.

[0068] [Experimental Example]

[0069] 1. Preparation of fiber-reinforced core material

[0070] As a fiber-reinforced core material for the experimental example, commercially available OPF (oxidized polyacrylonitrile fiber) was prepared.

[0071] 2. Preparation of impregnating solution

[0072] An impregnation solution was prepared by mixing 10 parts by weight of fumed silica, 4 parts by weight of a silane compound (MTMS, Methyl TriMethoxy Silane), 4 parts by weight of silica sol, and 100 parts by weight of water in a reaction vessel.

[0073] 3. Preparation of flame-retardant coating composition

[0074] After preparing flame-retardant coating compositions of Experimental Examples 1 to 9 and Experimental Examples 10 to 17 with the compositions presented in Tables 1 and 2 below, the physical properties of the coating films were evaluated.

[0075]

[0076] * MMA / BMA: MMA / BMA copolymerized acrylic resin

[0077] * RFL: TRIETHYL PHOSPHATE POLYMER WITH OXIRANE AND PHOSPHORUS OXIDE

[0078] * RDP: Resorcinol bis(diphenyl phosphate)

[0079]

[0080] * MMA / BMA: MMA / BMA copolymerized acrylic resin

[0081] * RFL: TRIETHYL PHOSPHATE POLYMER WITH OXIRANE AND PHOSPHORUS OXIDE

[0082] * RDP: Resorcinol bis(diphenyl phosphate)

[0083] The physical properties, manufacturer, and / or product name of each component used in the experimental example are presented in Table 3 below.

[0084]

[0085] 4. Manufacturing of sheets to prevent battery thermal runaway

[0086] 4-1. Manufacturing of flame-retardant composite sheets

[0087] A flame-retardant composite sheet was manufactured by impregnating the prepared fiber-reinforced core material with the manufactured impregnation solution.

[0088] Specifically, the fiber-reinforced core material was cut into 300 mm x 300 mm x 4 mm sizes, immersed in a bath containing an impregnation solution for 5 seconds, and then dried in a 150°C oven for 60 minutes to harden.

[0089] 4-2. Manufacturing of sheets to prevent battery thermal runaway

[0090] A flame-retardant coating layer was formed by coating the manufactured flame-retardant coating solution on both sides of the manufactured flame-retardant composite sheet.

[0091] [Evaluation of the physical properties of the coating]

[0092] 1) Evaluation of the coating appearance

[0093] Each section of the specimen is measured using a surface roughness meter. Surface roughness refers to the degree of microscopic irregularities on the surface. Surface roughness is determined by the processing method, processing tools, and surface flaws. Surface roughness is defined by the following three methods.

[0094] Ra is the centerline average roughness, which is a method of measuring the average height when the reference length (centerline average) is assumed to be flat without roughness.

[0095] Rmax and Ry define the sample section with the maximum height roughness, and measure the vertical distance from the highest to the lowest point of this curve section. Finally, Rz and Rs are the ten-point average roughness values. These values ​​are calculated by drawing a straight line parallel to the mean line of the cross-section and measuring the distance between the fifth highest peak and the fifth lowest valley, and calculating the difference in averages.

[0096] In the present invention, the appearance of the coating film was evaluated using the Ra value. An Ra value of 0.2 to 1.0 ㎛ is excellent, and the smaller the value, the more uniform the appearance of the coating film.

[0097] 2) Evaluation of film flexibility

[0098] This refers to a test that bends to a certain angle using a jig with a specified bending radius to investigate the ductility of the base material. The bending test is classified into surface bending, back bending, and side bending depending on the tensile side, and is also classified into guide bending, roller bending, and free bending depending on the shape that applies the bending load. In the present invention, a bending test using the pressing bending method is performed among these, and after bending to approximately 170 to 180 degrees, the presence or absence of cracks or other defects on the surface of the specimen is inspected. The radius size of the pressing jig varies depending on the thickness of the specimen during the bending test, and in the present invention, a jig with a radius of 0.5T was used.

[0099] 3) Flame retardant performance evaluation (combustion time)

[0100] After drying the specimen in an 80 degree oven for 1 hour, heat the center of the specimen with a flame length of 60 mm for 2 minutes and measure the time until the specimen is completely carbonized and there is no more appearance deformation, whether it catches fire or not.

[0101] The results of the physical property evaluation of the coating are presented in Tables 4 and 5 below.

[0102]

[0103]

[0104] * Coating appearance (filling) (G: Excellent, ○: Good, △: Poor, X: Poor)

[0105] * Film flexibility (number of times the film starts to break when repeatedly bent 0.6 mm): Less than 8 times - poor, 8 to 15 times - good, 15 times or more - excellent

[0106] * Burning time (time until the coating film is completely burned and no longer catches fire): The shorter the better (less than 40 seconds is excellent)

[0107] * The smaller the Ra, the better (0.2 ~ 1.0 ㎛ is excellent)

[0108] As shown in Tables 4 and 5, Experimental Examples 10, 11, 13, and 15 had poor coating film appearance, and Experimental Examples 16 and 17 had insufficient coating film appearance. Meanwhile, the combustion times of Experimental Examples 12, 14, 16, and 17 did not meet the standard. Experimental Example 10 had an Ra (coating roughness) value exceeding the standard, confirming poor physical properties.

[0109] Hereinafter, various embodiments of the present invention will be described.

[0110] [Specific Example 1] A flame-retardant coating composition comprising a water-soluble resin having a solid content of 3 to 40 parts by weight, a flame retardant having a solid content of 40 to 80 parts by weight, an additive having a solid content of 0.1 to 10 parts by weight, and a solvent having a solid content of 5 to 30 parts by weight, wherein the flame retardant comprises a phosphorus-based flame retardant having a solid content of 0.1 to 25 parts by weight and a metal hydroxide-based flame retardant having a solid content of 20 to 45 parts by weight.

[0111] [Specific Example 2] In Specific Example 1, the water-soluble resin is a flame-retardant coating composition comprising at least one selected from the group consisting of ethylene vinylacetate (EVA) resin, polyvinylchloride resin, water-soluble acrylic resin, polyvinylacetate (PVAC) resin, polybutadiene resin, polyvinylidene chloride resin, and polyurethane (PU) resin.

[0112] [Specific Example 3] A flame-retardant coating composition according to Specific Example 1, further comprising a solid content of a thermoplastic resin of 0 to 20 parts by weight.

[0113] [Specific Example 4] A flame retardant coating composition according to Specific Example 1, wherein the flame retardant is a non-halogen flame retardant.

[0114] [Specific Example 5] In Specific Example 1, the phosphorus flame retardant is a flame retardant coating composition comprising at least one selected from the group consisting of ammonium polyphosphate (APP), triphenyl phosphate (TPP), tricresyl phosphate (TCP), triethyl phosphate (TEP), isopropyl phenyl diphenyl phosphate, red phosphorus (CG-P), tris(2-chloroethyl)phosphate (TCEP), and resorcinol di phosphate (RDP).

[0115] [Specific Example 6] In Specific Example 1, the metal hydroxide-based flame retardant is a flame retardant coating composition comprising at least one selected from the group consisting of aluminum hydroxide (Al(OH)3), calcium hydroxide (Ca(OH)2), and magnesium hydroxide (Mg(OH)2).

[0116] [Specific Example 7] A flame-retardant coating composition according to Specific Example 1, wherein the weight ratio of the phosphorus-based flame retardant and the metal hydroxide-based flame retardant is 1:1 to 1:30 based on solid content.

[0117] [Specific Example 8] In Specific Example 3, a flame retardant coating composition in which the ratio (A or A':B) of the weight of the water-soluble resin (A), or the sum of the weight of the water-soluble resin and the weight of the thermoplastic resin (A') and the weight of the flame retardant (B) is 1:1 to 1:10 based on the solid content.

[0118] [Specific Example 9] A flame retardant coating composition according to Specific Example 1, wherein the flame retardant further comprises 20 to 40 parts by weight of a solid content of filler.

[0119] [Specific Example 10] A flame-retardant coating composition according to Specific Example 1, wherein the additive comprises at least one of an aqueous dispersant and a pigment.

[0120] [Specific Example 11] A flame-retardant coating layer formed using the flame-retardant coating composition according to any one of Specific Examples 1 to 10.

[0121] [Specific Example 12] A sheet for preventing battery thermal runaway, comprising a flame-retardant composite sheet and the flame-retardant coating layer according to Specific Example 11 formed on the upper or lower surface of the flame-retardant composite sheet, wherein the flame-retardant composite sheet is manufactured by impregnating a fiber-reinforced core material with an impregnating solution containing silica, and the fiber-reinforced core material comprises at least one selected from the group consisting of polyester, polyacrylonitrile (PAN), oxidized polyacrylonitrile, non-carbonized heat-treated PAN, carbon, silica, polyaramid, polycarbonate, polyolefin, rayon, nylon, glass wool, high-density polyolefin, ceramic, acrylic, fluoropolymer, polyurethane, polyamide, and polyimide, and the impregnating solution comprises a solvent and the silica, and the silica is selected from the group consisting of fumed silica, precipitated silica, silica glass, and optical fiber (silicon ester). A sheet for preventing battery thermal runaway, comprising at least one selected type.

[0122] [Specific Example 13] In Specific Example 12, the battery thermal runaway prevention sheet has a surface roughness (Ra) of 0.2 to 1.0 ㎛.

Claims

1. As a flame retardant coating composition, It comprises 3 to 40 parts by weight of solid content of water-soluble resin, 40 to 80 parts by weight of solid content of flame retardant, 0.1 to 10 parts by weight of solid content of additive, and 5 to 30 parts by weight of solvent. A flame retardant coating composition comprising a solid content of 0.1 to 25 parts by weight of a phosphorus-based flame retardant and a solid content of 20 to 45 parts by weight of a metal hydroxide-based flame retardant.

2. In claim 1, A flame retardant coating composition, wherein the water-soluble resin comprises at least one selected from the group consisting of ethylene vinylacetate (EVA) resin, polyvinylchloride resin, water-soluble acrylic resin, polyvinylacetate (PVAC) resin, polybutadiene resin, polyvinylidene chloride resin, and polyurethane (PU) resin.

3. In claim 1, A flame retardant coating composition further comprising a solid content of a thermoplastic resin of 0 to 20 parts by weight.

4. In claim 1, A flame retardant coating composition wherein the flame retardant is a non-halogen flame retardant.

5. In claim 1, A flame retardant coating composition comprising at least one selected from the group consisting of ammonium polyphosphate (APP), triphenyl phosphate (TPP), tricresyl phosphate (TCP), triethyl phosphate (TEP), isopropyl phenyl diphenyl phosphate, red phosphorus (CG-P), tris(2-chloroethyl)phosphate (TCEP), and resorcinol di phosphate (RDP).

6. In claim 1, A flame retardant coating composition comprising at least one metal hydroxide-based flame retardant selected from the group consisting of aluminum hydroxide (Al(OH)3), calcium hydroxide (Ca(OH)2), and magnesium hydroxide (Mg(OH)2).

7. In claim 1, A flame retardant coating composition, wherein the weight ratio of the above-mentioned phosphorus-based flame retardant and the above-mentioned metal hydroxide-based flame retardant is 1:1 to 1:30 based on solid content.

8. In claim 3, A flame retardant coating composition, wherein the ratio (A or A':B) of the weight of the water-soluble resin (A), or the sum of the weight of the water-soluble resin and the weight of the thermoplastic resin (A') and the weight of the flame retardant (B) is 1:1 to 1:10 based on the solid content.

9. In claim 1, A flame retardant coating composition further comprising 20 to 40 parts by weight of a solid content of a filler.

10. In claim 1, A flame retardant coating composition, wherein the additive comprises at least one of an aqueous dispersant and a pigment.

11. A flame-retardant coating layer formed using the flame-retardant coating composition according to any one of claims 1 to 10.

12. A sheet for preventing battery thermal runaway, comprising a flame-retardant composite sheet and a flame-retardant coating layer according to claim 11 formed on the upper or lower surface of the flame-retardant composite sheet, The above flame retardant composite sheet is manufactured by impregnating a fiber-reinforced core material with an impregnating liquid containing silica. The above fiber-reinforced core material comprises at least one selected from the group consisting of polyester, polyacrylonitrile (PAN), oxidized polyacrylonitrile, non-carbonized heat-treated PAN, carbon, silica, polyaramid, polycarbonate, polyolefin, rayon, nylon, glass wool, high-density polyolefin, ceramic, acrylic, fluoropolymer, polyurethane, polyamide, and polyimide. The impregnating liquid contains a solvent and the above silica, A sheet for preventing thermal runaway of a battery, wherein the silica comprises at least one selected from fumed silica, precipitated silica, silica glass, and silicon ester.

13. In claim 12, The above battery thermal runaway prevention sheet is a battery thermal runaway prevention sheet having a surface roughness (Ra) of 0.2 to 1.0 ㎛.

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