Heat-absorbing pad

Abstract

The present application relates to a heat-absorbing pad. The heat-absorbing pad can exhibit excellent thermal transfer delay characteristics, and can exhibit a uniform insulation temperature by forming a carbonized film against flames. The heat-absorbing pad can be effectively used to delay heat transfer to adjacent battery cells in the event of thermal runaway in a battery cell.

Description

heat absorbing pad

[0001] This application relates to a heat-absorbing pad. This application claims the benefit of priority from Korean Patent Application No. 10-2024-0085322, filed June 28, 2024, and all disclosures contained in that Korean patent application are incorporated herein by reference.

[0002] Thermal runaway in a battery occurs when the thermal stability of the chemicals within the cell exceeds its limit, causing the cell to rapidly release its internal energy to the outside. Thermal runaway is defined as a drop in the measured voltage of the cell, a measured temperature of dT / dt ≥ [4℃ / s], and exceeding the maximum operating temperature (approximately 120℃). Causes of thermal runaway include overcharging, collisions / drops, heat exposure, high voltage / current exposure, and external / internal short circuits. When thermal runaway begins, the internal pressure of the battery increases, causing combustible materials to erupt and ignite. This then heats adjacent cells and rapidly spreads into a fire. Battery fires are classified as electrical fires and are currently being extinguished using gas-based fire extinguishing systems. However, the battery module has a metal protective cover that makes it difficult for extinguishing agents to penetrate. In addition, when thermal runaway occurs, the temperature can quickly rise to 1000℃, so agent release must occur at the initial stage of the fire. Therefore, to stop thermal runaway, only sufficient cooling or total combustion in the early stages of a fire is the ultimate extinguishment (Prior Art Document 1: Republic of Korea Patent Publication No. 10-2020-0107214).

[0003] Phase change materials (PCMs) are materials that release and absorb energy through a phase transition, providing heat and cooling. The latent heat of the phase transition is higher than the typical sensible heat, and they store and release large amounts of energy when they transition from a solid or liquid state to another at their phase change temperature (PCT). PCMs are used in applications requiring energy storage and stable temperatures, such as heating pads, cooling devices, and clothing.

[0004] The present application relates to a heat-absorbing pad. The heat-absorbing pad can exhibit excellent heat transfer delay characteristics and form a carbon film against a flame, thereby exhibiting a uniform thermal insulation temperature. The heat-absorbing pad can be usefully used to delay heat transfer to adjacent battery cells during thermal runaway of a battery cell.

[0005] The present application relates to a heat absorbing pad. The heat absorbing pad may have the property of absorbing heat generated in the surroundings. The heat absorbing pad may include a heat absorbing material. The heat absorbing pad may further include a binder resin. In one example, the heat absorbing pad may include a resin composition including the heat absorbing material and the binder resin in a cured state. That is, the heat absorbing pad may include a cured product of the resin composition. The heat absorbing pad may be the cured product of the resin composition itself. If another layer other than the cured product of the resin composition is further included, it may be referred to as a multilayer heat absorbing pad.

[0006] Among the properties mentioned in this specification, the properties whose results are affected by the measurement temperature and / or measurement pressure are the results measured at room temperature and / or atmospheric pressure, unless otherwise specified. The term room temperature in this specification refers to the natural temperature that has not been heated or cooled, and is typically a temperature in the range of about 10°C to 30°C, a temperature in the range of 20°C to 30°C, or about 23°C or about 25°C. The unit of temperature in this specification is ℃ unless otherwise specified. The term atmospheric pressure in this specification refers to the natural pressure that has not been pressurized or decompressed, and typically means about 1 atm of the atmospheric pressure level. The properties whose results are affected by the measurement humidity in this specification are, unless otherwise specified, the properties are the properties measured at the natural humidity that has not been separately controlled in the above-mentioned room temperature and atmospheric pressure conditions.

[0007] As used herein, an endothermic material may refer to a material that absorbs or consumes heat generated from its surroundings. An endothermic material may spontaneously decompose or produce new substances using the absorbed heat energy.

[0008] The above-described heat-absorbing pad and / or resin composition may include an endothermic material that undergoes an irreversible heat-absorbing reaction. The endothermic material may be a material that reacts irreversibly when heated and cooled. In one example, the endothermic material undergoes thermal decomposition through heat absorption when the ambient temperature increases, and does not return to the state of the endothermic material before thermal decomposition even when the ambient temperature decreases. The thermal decomposition may mean that the material chemically decomposes into a simpler substance when heat is applied. This irreversibility may be advantageous in exhibiting excellent heat transfer delay characteristics. On the other hand, paraffin, a representative phase change material (PCM), absorbs heat when the ambient temperature increases, melts, and becomes a liquid, and releases heat and returns to a solid state when the ambient temperature decreases. The phase change material is a material that reacts reversibly through heat absorption and exotherm. The resin composition may not include such a reversibly reacting phase change material.

[0009] Endothermic substances exist in a solid state at room temperature, and can undergo a phase change from solid to liquid at temperatures below 200°C. In this specification, the phase change from solid to liquid may refer to a phenomenon in which water molecules separate (dissociate) from the endothermic substance when the endothermic substance is heated. The temperature at which the phase change from solid to liquid of the endothermic substance occurs may be specifically 190°C or less, 180°C or less, 170°C or less, 160°C or less, 150°C or less, 140°C or less, 130°C or less, 120°C or less, 110°C or less, or 100°C or less, and may be 50°C or more, 60°C or more, 70°C or more, 80°C or more, 90°C or more, 100°C or more, 110°C or more, 120°C or more, 130°C or more, 140°C or more, 150°C or more, 160°C or more, 170°C or more, 180°C or more, or 190°C or more.

[0010] The endothermic substance may be a water-soluble substance. The water-soluble substance may refer to a substance having a solubility in water at 20°C of greater than 0 g / 100 ml. In one example, the solubility of the endothermic substance in water at 20°C may be greater than or equal to 5 g / 100 ml. The solubility of the endothermic substance in water may be specifically greater than or equal to 10 g / 100 ml, greater than or equal to 15 g / 100 ml, greater than or equal to 20 g / 100 ml, greater than or equal to 25 g / 100 ml, greater than or equal to 30 g / 100 ml, greater than or equal to 35 g / 100 ml, or greater than or equal to 40 g / 100 ml. The upper limit of the solubility of the endothermic substance in water may be, for example, 50 g / 100 ml or less. The solubility may be derived by adding 1 g of the endothermic substance to 100 ml of water at a temperature of 20°C and measuring the weight of the endothermic substance before a precipitate is formed.

[0011] The endothermic material may have thermal conductivity. In one example, the thermal conductivity (λ) of the endothermic material may be 20 W / mK or less. When the thermal conductivity of the endothermic material is within the above range, it may be advantageous for exhibiting excellent heat transfer delay characteristics. The thermal conductivity of the endothermic material may be specifically 15 W / mK or less, 10 W / mK or less, 5 W / mK or less, 4 W / mK or less, 3 W / mK or less, 2 W / mK or less, 1 W / mK or less, or 0.5 W / mK or less. The lower limit of the thermal conductivity of the endothermic material may be, for example, 0.001 W / mK or more. The thermal conductivity (λ) is a value defined by thermal diffusivity (α) × specific heat (Cp) × density (ρ). The thermal conductivity (λ) may be a value measured at a temperature of 25°C. The thermal conductivity of an endothermic material can be measured using a known thermal conductivity measuring device. Alternatively, the thermal conductivity of an endothermic material is generally known, and an endothermic material satisfying the above thermal conductivity can be used.

[0012] In one example, an endothermic material may have an endothermic peak temperature of less than 200°C when subjected to thermal analysis while being heated at a rate of 10°C / min from 0°C to 350°C using a differential scanning calorimeter. This may be advantageous in providing an endothermic pad having excellent compression performance and / or flame resistance. In the present specification, the endothermic peak temperature may refer to the temperature at which the absolute value of Heat Flow (W / g) is the largest in a graph of Heat Flow (W / g) (y-axis) versus Temperature (°C) (x-axis) obtained through thermal analysis using a differential scanning calorimeter. When the endothermic peak temperature is within the above range, it may be advantageous in exhibiting excellent heat transfer characteristics. The endothermic peak temperature may be, for example, 50°C or higher. The above endothermic peak temperature may be specifically 190°C or less, 180°C or less, 170°C or less, 160°C or less, 150°C or less, 140°C or less, 130°C or less, 120°C or less, 110°C or less, or 100°C or less, and may be 60°C or more, 70°C or more, 80°C or more, 90°C or more, 100°C or more, 110°C or more, 120°C or more, 130°C or more, 140°C or more, 150°C or more, 160°C or more, 170°C or more, 180°C or more, or 190°C or more.

[0013] In one example, an endothermic material may have a single endothermic peak (one endothermic peak) at a temperature below 200°C. In another example, an endothermic material may have distributed endothermic peaks (two or more endothermic peaks) at a temperature below 200°C. Having two or more endothermic peaks may mean having one endothermic peak with the highest absolute value of Heat Flow (W / g) and one or more additional endothermic peaks with the next highest absolute value of Heat Flow (W / g). Assuming the same amount of heat absorption, an endothermic material with a single peak may have better heat transfer delay characteristics. Examples of endothermic substances having a single peak include AlCl3·6H2O, MgSO4·7H2O, NiSO4·6H2O, Na4P2O7·10H2O, Sr(OH)2·8H2O, and CaSO4·2H2O.

[0014] In one example, an endothermic material may have an endothermic quantity of 500 J / g or more. In the present specification, the endothermic quantity may refer to the total amount of heat (integrated value on a DSC graph) from the point at which endothermic initiation occurs to the point at which endothermic initiation occurs. Specifically, the endothermic quantity may be obtained by calculating the area of ​​the graph of the endothermic section (by integrating the graph of the endothermic section) in a graph of Heat Flow (W / g) (y-axis) against temperature (℃-axis) obtained through thermal analysis using a differential scanning calorimeter. The endothermic section may refer to a section from the endothermic initiation temperature to the endothermic end temperature in the graph. The area may refer to the area of ​​a closed graph formed by a straight line (A) connecting a graph point at the endothermic initiation temperature and a graph point at the endothermic end temperature, and a continuous graph (B) of the section from the endothermic initiation temperature to the endothermic end temperature. When the endothermic quantity is within the above range, it may be advantageous for exhibiting excellent heat transfer characteristics. The above heat absorption may be specifically 600 J / g or more, 700 J / g or more, 800 J / g or more, 900 J / g or more, 1,000 J / g or more, 1,100 J / g or more, 1,200 J / g or more, 1,300 J / g or more, 1,400 J / g or more, 1,500 J / g or more, 1,600 J / g or more, or 1,700 J / g or more, and may be 2,000 J / g or less. The above heat absorption may be a value measured while heating at a rate of 10 ℃ / min using a differential scanning calorimeter (DSC Q2000, TA Corporation).

[0015] The endothermic material may include a material containing water and / or a solid acid. The material containing water may include hydrate particles and / or water microcapsules. The solid acid may be a solid acid particle that exists in a solid state at room temperature, for example, at about 25°C.

[0016] In one example, the endothermic material may be a hydrate particle. The hydrate particle may refer to a particle containing water molecules (H2O). When the hydrate particle is applied as the endothermic material, water molecules may be dissociated from the endothermic material by the thermal decomposition. This may be advantageous in exhibiting excellent heat transfer delay characteristics. The hydrate particle may be an inorganic salt containing water molecules bonded to crystals of a metal compound. The water contained in the hydrate particle may be referred to as crystal water. The hydrate particle is different from a hydroxide particle, and the hydroxide particle may refer to a material containing -OH (-hydroxyl group) but not containing H2O.

[0017] The hydrate particles are specifically (NH4)2O·5B2O3·8H2O, (Mg(H2PO4)2)·3H2O, (Mg(H2PO4)2)·4H2O, (Mg(H2PO4)2)·5H2O, (Mg(H2PO4)2)·8H2O, MgCl2·6H2O, AlCl3·6H2O, Na4P2O7·10H2O, KAl(SO4)2·12H2O, NiSO4·6H2O, Mg(NO3)2·6H2O, CoSO4·7H2O, (NH4)2Fe(SO4)2·6H2O, CuSO4·5H2O, ZnSO4·7H2O, CoCl2·6H2O, CrCl3·6H2O, NiCl2·6H2O, MgSO4·7H2O, It may include at least one selected from the group consisting of Al2(SO4)3·18H2O, Na2B4O7·10H2O, Sr(OH)2·8H2O, CaC2O4·H2O, Ba(OH)2·8H2O, Ba(OH)2·H2O, Mg3(PO4)2·5H2O, Mg3(PO4)2·8H2O, and FeSO4·7H2O.

[0018] In another example, the endothermic substance may be a solid acid. The solid acid may be a solid acid that undergoes an irreversible endothermic reaction. In one example, the solid acid may be an inorganic acid or an organic acid. The solid acid may include at least one selected from the group consisting of boric acid, benzoic acid, stearic acid, salicylic acid, acetic acid, tartaric acid, citric acid, maleic acid, palmitic acid, and oxalic acid. In one example, the solid acid may be boric acid.

[0019] In another example, the heat-absorbing material may be a water microcapsule. The microcapsule may include a capsule portion and water contained within the capsule portion. The capsule portion may include at least one selected from the group consisting of poly(vinyl alcohol), poly(ethylene oxide), polyethylene glycol, poly(methyl methacrylate), butyl acrylate, and silicate. The size of the microcapsule may be, for example, in the range of 50 μm to 500 μm.

[0020] The content of the endothermic material may be appropriately selected within a range that does not impair the purpose of the present application. In one example, the endothermic material may be included in an amount ranging from 50 to 1,000 parts by weight relative to 100 parts by weight of the binder resin. Specifically, the heat-absorbing material may be included in an amount of 50 parts by weight or more, 100 parts by weight or more, 150 parts by weight or more, 200 parts by weight or more, 250 parts by weight or more, 300 parts by weight or more, 350 parts by weight or more, or 400 parts by weight or more, and may be included in an amount of 1,000 parts by weight or less, 900 parts by weight or less, 800 parts by weight or less, 700 parts by weight or less, 600 parts by weight or less, 500 parts by weight or less, 450 parts by weight or less, 400 parts by weight or less, 350 parts by weight or less, 300 parts by weight or less, 250 parts by weight or less, or 200 parts by weight or less, based on 100 parts by weight of the binder resin. The content of the heat-absorbing material within the above range is suitable for manufacturing a heat-absorbing pad and may be advantageous in exhibiting excellent heat transfer delay characteristics.

[0021] The binder resin may include a main resin. The main resin may be a silicone resin. Accordingly, the heat-absorbing pad may include a silicone resin. That is, the heat-absorbing pad may be a cured product of a resin composition comprising a silicone resin and a heat-absorbing material. When a silicone resin is used as the main resin, it may be advantageous in exhibiting excellent heat transfer delay characteristics and / or flame resistance characteristics. In particular, even when an endothermic material or a solid acid containing water is used as the heat-absorbing material, since no change or water generation occurs over time after mixing the main resin and the heat-absorbing material, excellent heat transfer delay characteristics and / or flame resistance characteristics may be exhibited. Meanwhile, organic materials such as urethane resins or epoxy resins burn in flames, but in the case of silicone resins, the Si-O-Si siloxane chains are converted to SiO2 by heat, so that the flame resistance may be superior.

[0022] The silicone resin may be polydimethylsiloxane having vinyl groups at both ends. The silicone resin may be a compound represented by the following chemical formula 1. In the following chemical formula 1, n may be an integer greater than or equal to 1, and may be appropriately selected in consideration of the molecular weight of the silicone resin.

[0023] [Chemical Formula 1]

[0024]

[0025] The molecular weight of the silicone resin may be selected within a range that does not impair the purpose of the present application. The molecular weight of the silicone resin refers to the molecular weight of the silicone polymer constituting the silicone resin. In one example, the molecular weight of the silicone resin may be 100,000 g / mol or less. When the molecular weight of the silicone resin is within the above range, the heat resistance performance may be improved, which may be more advantageous in exhibiting excellent heat transfer delay characteristics. Specifically, the molecular weight of the silicone resin may be 90,000 g / mol or less, 80,000 g / mol or less, 70,000 g / mol or less, 60,000 g / mol or less, 50,000 g / mol or less, 40,000 g / mol or less, 30,000 g / mol or less, 25,000 g / mol or less, 20,000 g / mol or less, 15,000 g / mol or less, or 10,000 g / mol or less. The lower limit of the molecular weight of the above silicone resin may be 100 g / mol or more, 500 g / mol or more, or 1,000 g / mol from the viewpoint of handling the manufactured pad.

[0026] The viscosity of the silicone resin may be selected within a range that does not impair the purpose of the present application. In one example, the viscosity of the silicone resin may be 150,000 cSt or less. When the viscosity of the silicone resin is within the above range, it may be more advantageous in exhibiting excellent heat transfer delay characteristics. Specifically, the viscosity of the silicone resin may be 100,000 cSt or less, 80,000 cSt or less, 60,000 cSt or less, 40,000 cSt or less, or 20,000 cSt or less. The lower limit of the viscosity of the silicone resin may be 5 cSt or more, 10, cSt or more, 20 cSt or more, 40 cSt or more, 60 cSt or more, 80 cSt or more, or 100 cSt or more from the perspective of the pad manufacturing process. Regarding the viscosity of the silicone resin, for commercially available products, the seller provides information on the viscosity. Accordingly, a silicone resin product satisfying the above viscosity can be selected and used, and the viscosity measurement conditions can also follow those provided by the silicone resin vendor. As an example, the viscosity of the silicone resin can be measured using a BROOKFIELD DV-II+ viscometer under the conditions of a temperature of 25°C, a rotation speed of 10 rpm, and a spindle of 6.

[0027] The binder resin may further include a curing agent. The curing agent may be one suitable for curing the main resin. In one example, when the main resin is a silicone resin, a silane compound or a silanol compound may be used as the curing agent. The silane compound may refer to a compound having a -SiH (Silicon-hydride) group. The silanol compound may refer to a compound having a -Si-OH (Silicon-hydride) group. The -SiH group or -Si-OH group may react with a vinyl group of the silicone resin. The silane compound may have at least one -CH3 of a terminal and / or side chain. -It can be a polydimethylsiloxane substituted with H. In one example, the curing agent can be a pendent type curing agent. The pendent type curing agent can be a polydimethylsiloxane in which at least one -CH3 of the pendent type is substituted with -H, and both terminals are -CH3. In another example, the curing agent can be a hybrid type curing agent. The hybrid type curing agent can be a polydimethylsiloxane in which both terminals are substituted with -H, and at least one -CH3 of the pendent type is also substituted with -H.

[0028] In one example, the curing agent may be included in the resin composition so that the H / V ratio is within the range of 1 to 20. Wherein H is a value defined as H mmol / g × H wt%, and V is a value defined as V mmol / g × V wt%. In the above, H mmol / g means mmol of Si-H (silicon-hydrogen) per g of the curing agent included in the resin composition, and V mmol / g means mmol of Si-Vi (silicon-vinyl) per g of the silicone resin included in the resin composition. In the above, H wt% means a weight fraction of the curing agent with respect to the weight of the entire resin composition, and V wt% means a weight fraction of the silicone resin with respect to the weight of the entire resin composition. In the above, the weight fraction of the entire resin composition is 100 wt%.

[0029] The above-described heat-absorbing pad and / or resin composition may not contain an amine compound and an isocyanate compound. The amine compound and the isocyanate compound may not be suitable for mixing with a heat-absorbing material containing water or a solid acid. The amine compound may be a curing agent when an epoxy resin is used as the main resin, and the isocyanate compound may be a curing agent when a polyol resin is used as the main resin. According to the present application, the main resin may not contain an epoxy resin and a polyol resin.

[0030] The above-described heat-absorbing pad and / or resin composition may further include a catalyst. The catalyst may promote a reaction between the main resin and the curing agent. In one example, the catalyst may promote a hydrosilylation addition reaction between a carbon-carbon double bond of the silicone resin and a -SiH group of the curing agent. In another example, the catalyst may also promote a reaction between a carbon-carbon double bond of the silicone resin and a -Si-OH group of the curing agent. In one example, the catalyst may be a platinum group catalyst. The platinum group catalyst may include a platinum-based metal catalyst, a palladium-based metal catalyst, a rhodium-based metal catalyst, or a mixture thereof. In another example, the catalyst may be a metal salt catalyst. The metal salt catalyst may include a tin-based metal salt such as bis(2-ethylhexanoate)tin or dibutyldilauryltin, a zinc-based metal salt such as zinc octoate, an iron-based metal salt such as iron octoate, or a mixture thereof. The catalyst may be included in an amount of 0.01 to 10 parts by weight, 0.01 to 5 parts by weight, 0.01 to 3 parts by weight, 0.01 to 1 part by weight, or 0.01 to 0.5 parts by weight, based on 100 parts by weight of the binder resin.

[0031] The above-mentioned heat-absorbing pad and / or resin composition may further include additives in addition to the main resin, curing agent, and catalyst.

[0032] In one example, the heat-absorbing pad and / or resin composition may further include a dispersant. The dispersant may be, for example, an amino-silicone dispersant. The dispersant may be included in an amount of 0.1 to 10 parts by weight, 0.1 to 5 parts by weight, or 0.5 to 5 parts by weight, relative to 100 parts by weight of the binder resin.

[0033] In one example, the heat-absorbing pad and / or the resin composition may further include a chain extender. For example, a compound having -SiH (Silicon-hydride) at both ends may be used as the chain extender. The -SiH may react with a vinyl group of the silicone resin. In one example, the chain extender may be a polydimethylsiloxane in which -CH3 at both ends is replaced with -H and the side chain is -CH3. When the resin composition includes both a curing agent and a chain extender, the curing agent and the chain extender may be included in the resin composition such that the H / V ratio is within a range of 1 to 20. The H is a value defined as (H1mmol / g × H1wt% + H2mmol / g × H2wt%), and V is a value defined as V mmol / g × V wt%. In the above, H1mmol / g means mmol of Si-H (silicone-resin) per g of the curing agent included in the resin composition, H2mmol / g means mmol of Si-H (silicone-resin) per g of the chain extender included in the resin composition, and V mmol / g means mmol of Si-Vi (silicone-vinyl) per g of the silicone resin included in the resin composition. In the above, H1wt% means the weight fraction of the curing agent with respect to the weight of the entire resin composition, H2wt% means the weight fraction of the chain extender with respect to the weight of the entire resin composition, and V wt% means the weight fraction of the silicone resin with respect to the weight of the entire resin composition. In the above, the weight fraction of the entire resin composition is 100 wt%.

[0034] In one example, the absorbent pad and / or resin composition may further include a curing retardant. The curing retardant may be, for example, a compound having a carbon-carbon double bond or a carbon-carbon triple bond. The above curing retardant is 1-ethynyl-1-cyclohexanol, 3-methyl-1-penten-3-ol, 2-methyl-3-butyn-2-ol, 3-phenyl-3-butyn-2-ol, 2-phenyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 1,5-hexadiine, 1,6-heptadiine, 3,5-dimethyl-1-hexyne, 2-ethyl-3-butyne, 2-phenyl-3-butyne, 1,3-divinyltetramethyldisiloxane, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane, 1,3-divinyl-1,3-diphenyldimethyldisiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane and The curing retardant may be one or more selected from the group consisting of divinyl-1,1,3,3-detramethyldisilazane, but is not limited thereto. The curing retardant may be included in an amount of 0.1 to 10 parts by weight, 0.1 to 5 parts by weight, or 0.5 to 5 parts by weight, based on 100 parts by weight of the binder resin.

[0035] According to the present application, the heat absorbing pad and / or resin composition may further include a flame retardant. The heat absorbing pad and / or resin composition may exhibit a uniform insulating temperature by forming a carbon film against a flame by including a suitable flame retardant. The carbon film may be formed by the flame retardant mechanism of a phosphorus-based flame retardant. Specifically, when a flame is applied to a phosphorus-based flame retardant, polyphosphoric acid is generated through thermal decomposition, and Char is formed through esterification and dehydrogenation. The carbon film may be a film formed by Char on the surface of the heat absorbing pad. The carbon film may exhibit a flame retardant effect by blocking heat and oxygen.

[0036] The above flame retardant may be a phosphorus-based flame retardant. That is, the heat-absorbing pad may be a cured product of a resin composition including a silicone resin, a heat-absorbing material, and a phosphorus-based flame retardant. The phosphorus-based flame retardant may refer to a flame retardant including a phosphorus component. The phosphorus-based flame retardant may include a phosphinate compound and / or a phosphate compound. In one example, the flame retardant may include a phosphinate-based compound such as aluminum diethyl phosphinate. In another example, the flame retardant may include one or more phosphate compounds selected from the group consisting of ammonium polyphosphate (APP), red phosphors (CG-P), tris(2-chloroethyl) phosphate (TCEP), isopropylphenyl diphenyl phosphate (IPPP), tris(1-chloro-2-propyl) phosphate (TCPP), triphenyl phosphate (TPP), and triethyl phosphate (TEP). In another example, the flame retardant may include both phosphinate compounds and phosphate compounds.

[0037] The flame retardant may be a solid flame retardant or a liquid flame retardant. The solid or liquid states may refer to the state at room temperature. The solid flame retardant may be, for example, a flame retardant in the form of a filler.

[0038] In one example, the thermal pad and / or resin composition may further include a metal hydroxide as a flame retardant. The metal hydroxide may include aluminum hydroxide and / or magnesium hydroxide. The metal hydroxide may be included in an amount of 10 to 500 parts by weight based on 100 parts by weight of the phosphorus-based flame retardant. In another example, the thermal pad and / or resin composition may include a phosphorus-based flame retardant, but may not include a metal hydroxide.

[0039] In one example, a coating layer may be present on the surface of the phosphorus flame retardant. The coating layer may be appropriately selected in consideration of the desired function to be added to the flame retardant. The coating layer may include, for example, at least one selected from the group consisting of a silicone-based coating layer, an epoxy-based coating layer, a melamine-based coating layer, and a silane-epoxy-based coating layer. In one example, the coating layer may be an epoxy-based coating layer or a silane-epoxy-based coating layer. As a specific example, when an APP (Ammonium Polyphosphate) flame retardant has the coating layer, it may exhibit better water resistance.

[0040] In one example, the phosphorus-based flame retardant may be included in an amount ranging from 10 to 100 parts by weight per 100 parts by weight of the endothermic material. Specifically, the phosphorus-based flame retardant may be included in an amount of at least 15 parts by weight, at least 20 parts by weight, at least 25 parts by weight, at least 30 parts by weight, at least 35 parts by weight, or at least 40 parts by weight, and may be included in an amount of at most 90 parts by weight, at most 80 parts by weight, at most 70 parts by weight, or at most 60 parts by weight, per 100 parts by weight of the endothermic material.

[0041] In one example, the thermal pad and / or resin composition may further include a flame retardant additive. The flame retardant additive may be added to the thermal pad and / or resin composition together with the flame retardant to further improve flame retardancy, and may include, for example, polytetrafluoroethylene (PTFE). When the thermal pad and / or resin composition further includes a flame retardant, it may be advantageous in terms of improving the heat transfer delay time, suppressing cracking due to flame, and reducing the final insulation temperature.

[0042] In one example, the viscosity of the resin composition may be 500,000 cps or less. When the viscosity of the resin composition is within the above range, it may be advantageous in manufacturing a heat-absorbing pad through curing, and the heat-absorbing pad manufactured therefrom may exhibit excellent heat transfer delay characteristics. Specifically, the viscosity of the resin composition may be 450,000 cps or less, 400,000 cps or less, 350,000 cps or less, 300,000 cps or less, 250,000 cps or less, 200,000 cps or less, 150,000 cps or less, or 100,000 cps or less. The lower limit of the viscosity of the above resin composition may be 1,000 cps or more, 5,000 cps or more, 10,000 cps or more, 30,000 cps or more, or 50,000 cps or more from the viewpoint of the pad manufacturing process. The viscosity is measured using a Brookfield DV2T HB viscometer at a temperature of 25°C, a rotation speed of 1.2 rpm, and a shear rate (sec). -1 ) 2.4, may be a value measured under the conditions of spindle CPA 52Z.

[0043] In one example, the resin composition may be a room temperature curable resin composition. Accordingly, the resin composition may be cured by maintaining it at room temperature (e.g., about 20°C to 30°C), and may not require a separate process for curing, such as application of moisture, application of heat, or irradiation with active energy rays (e.g., ultraviolet rays). In addition, considering that the resin composition may be used as a heat-absorbing pad, including a heat-absorbing material, it may be more advantageous to be a room temperature curable type because it may be sensitive to heat that may accompany a phase change of the heat-absorbing material. In addition, a room temperature curable resin composition may also be advantageous when curing must be performed inside a battery, as applying heat to the battery for curing inside the battery may be dangerous. In addition, a room temperature curable resin composition may be advantageous in that the curing speed can be easily controlled because it can be cured by applying heat when necessary. That is, in this specification, the room temperature curable resin composition means a resin composition that can be cured even by maintaining it at room temperature, and is not limited to a resin composition that is cured only by maintaining it at room temperature.

[0044] In one example, the resin composition may be a thermosetting resin composition. That is, the resin composition may be cured by the application of heat. The heating temperature and heating time for the curing may be selected within a range appropriate for manufacturing the heat-absorbing pad. The heating temperature may be performed within a range that appropriately cures the resin composition without causing damage to the heat-absorbing material. In one example, the heating temperature for the curing may be within a range of 50°C to 200°C. The heating time may be within a range of, for example, 1 minute to 20 minutes.

[0045] The above-mentioned heat-absorbing pad may have an endothermic amount of 200 J / g or more during thermal analysis while heating at a rate of 10°C / min from 0°C to 350°C using a differential scanning calorimeter. In addition, the above-mentioned heat-absorbing pad may have an endothermic peak temperature of less than 200°C during thermal analysis while heating at a rate of 10°C / min from 0°C to 350°C using a differential scanning calorimeter. The definitions of the endothermic amount and the endothermic peak temperature of the above-mentioned heat-absorbing pad may be applied identically to the definitions of the endothermic amount and the endothermic peak temperature of the above-mentioned heat-absorbing material, except that the measurement target is changed from the endothermic material to the endothermic pad. The endothermic pad having the above-mentioned characteristics may have excellent compression performance and flame resistance. The endothermic peak temperature may be, for example, less than 200°C, 190°C or less, 180°C or less, or 170°C or less. The lower limit of the above-mentioned endothermic peak temperature may be, for example, 100°C or higher, 120°C or higher, 140°C or higher, or 160°C or higher. The heat absorption amount of the above-mentioned heat absorption pad may be, for example, 250 J / g or higher, 300 J / g or higher, 350 J / g or higher, 400 J / g or higher, 450 J / g or higher, 500 J / g or higher, 550 J / g or higher, or 600 J / g or higher. The upper limit of the heat absorption amount of the above-mentioned heat absorption pad may be, for example, 2,000 J / g or lower, 1,500 J / g or lower, 1,000 J / g or lower, or 800 J / g or lower.

[0046] In one example, the heat-absorbing pad may have a porous structure. A heat-absorbing pad having a porous structure may be referred to as a heat-absorbing foam pad. In one example, the density of the heat-absorbing foam pad is 1 g / cm. 3 The density of the above-mentioned heat-absorbing foam pad may be, for example, 0.9 g / cm 3 Below 0.8 g / cm 3 Below 0.7 g / cm 3 Less than or equal to 0.6 g / cm 3 It may be less than or equal to 0.1 g / cm. The lower limit of the density of the above-mentioned heat-absorbing foam pad is, for example, 0.1 g / cm. 3or more than 0.2 g / cm 3 or more than 0.3 g / cm 3 It could be strange.

[0047] In one example, the heat-absorbing foam pad can be obtained by including a solvent in a resin composition for manufacturing the heat-absorbing pad and evaporating the solvent to form a porous structure. In another example, the heat-absorbing foam pad can be obtained by including foam particles in a resin composition for manufacturing the heat-absorbing pad to form a porous structure.

[0048] In the method of forming a porous structure by evaporating the solvent, the solvent may be an organic solvent. The conditions for evaporating the solvent may be performed within a range suitable for forming a porous structure in the heat absorbing pad while curing it. The temperature for evaporating the solvent may be higher than the boiling point of the solvent used. In one example, the organic solvent component may have a boiling point of 65°C or higher. The boiling point of the organic solvent component may be, for example, within a range of 65°C to 150°C. The boiling point may be 65°C or higher, 70°C or higher, 75°C or higher, 80°C or higher, 85°C or higher, 90°C or higher, 95°C or higher, 100°C or higher, or 105°C or higher, and may be 145°C or lower, 140°C or lower, 135°C or lower, 130°C or lower, 125°C or lower, 120°C or lower, 115°C or lower, 105°C or lower, 100°C or lower, 95°C or lower, 90°C or lower, 85°C or lower, or 80°C or lower.

[0049] In one example, the compression ratio of the heat-absorbing foam pad may be 3,000 g / mm or less. Specifically, the compression ratio may be 2,500 g / mm or less, 2,000 g / mm or less, 1,500 g / mm or less, or 1,000 g / mm or less. The lower limit of the compression ratio may be, for example, 100 g / mm or more. The compression ratio may be a value measured by a TA (Texture Analyzer), and may be a value measured by the method described in 'Evaluation Example 3. Compression ratio measurement' described below.

[0050] In another example, the heat absorbing pad may not have a porous structure. A heat absorbing pad without a porous structure may be referred to as a heat absorbing sheet to distinguish it from a heat absorbing foam pad. In the present specification, the heat absorbing pad not having a porous structure may mean a heat absorbing pad that has not undergone an intentional process to form a porous structure. Accordingly, the heat absorbing sheet may not include foaming particles (foaming agent) for foaming and a solvent for evaporation. The density of the heat absorbing sheet is 1 g / cm. 3 It may be exceeded. The upper limit of the density of the above-mentioned absorbent hard pad is, for example, 5 g / cm 3 It could be as follows:

[0051] The above-described heat-absorbing pad may have a heat transfer delay effect. In the present specification, the heat transfer delay effect may mean that when a flame is radiated to a single heat-absorbing pad (in a state where no other layers that affect the thermal characteristics of the heat-absorbing pad are laminated), the heat-absorbing pad absorbs heat and has a section in which the temperature of the heat-absorbing pad does not rise and is maintained for a certain period of time. When an heat-absorbing pad having a heat transfer delay effect is applied to a battery cell, even if the battery cell to which the heat-absorbing pad is applied ignites, the heat transfer to an adjacent battery cell can be effectively delayed. When describing the characteristics of the heat-absorbing pad with respect to a flame in the present specification, the flame may mean a flame caused by the combustion of LPG gas (Liquid Petroleum Gas) or butane gas. The temperature of the flame may be, for example, about 1000°C or higher. The upper limit of the flame temperature may be, for example, 2000°C or lower or 1500°C or lower.

[0052] That the absorbent pad has a heat transfer delay effect may mean that the absorbent pad has a heat transfer delay section. The heat transfer delay section may be defined as a continuous section in which the temperature change is less than 10°C or less than 5°C in a graph of temperature (°C) versus time (second) measured while applying a flame to the absorbent pad. That the temperature change is less than 10°C or less than 5°C means that the temperature increase per second within the section is less than 10°C or less than 5°C. More specifically, that the temperature change is less than 10°C or less than 5°C may mean that, when times t1 and t2 are selected at 1-second intervals within the section (t1-t2=1 second), the absolute value of the difference between the temperature T1 at t1 and the temperature T2 at t2 is less than 10°C or less than 5°C (the absolute value of T1-T2<10°C or the absolute value of T1-T2≤5°C).

[0053] The above heat transfer delay period may be due to an endothermic reaction of an endothermic material. In one example, in a graph of temperature (℃) versus time (second) measured while applying a flame to an endothermic pad, a heat transfer delay period may appear after a temperature rise period. In the temperature rise period, the starting temperature (temperature at 0 seconds) is approximately 25℃, and the temperature may increase almost linearly until the start time of the heat transfer delay period. Thereafter, the temperature may be almost constant during the heat transfer delay period. After the heat transfer delay period, a temperature rise period may appear again. If a distinction is necessary, the temperature rise period before the heat transfer delay period may be referred to as the first temperature rise period, and the temperature rise period after the heat transfer delay period may be referred to as the second temperature rise period. After the second temperature rise period, the temperature may converge to a constant temperature again, and the temperature at this time may be referred to as the final adiabatic temperature. The final insulation temperature may occur, for example, at about 3 minutes, about 5 minutes, or about 10 minutes after irradiating the flame to the absorbent pad.

[0054] The above heat-absorbing pad can exhibit excellent flame-insulating performance. The heat-absorbing pad can form a carbon film against the flame and exhibit an insulation temperature of about 500°C or less. Specifically, after irradiating a flame to one side of the heat-absorbing pad for 10 minutes, the temperature on the opposite side to the side to which the flame was irradiated can be 500°C or less. Specifically, the insulation temperature can be 475°C or less, 450°C or less, 425°C or less, 400°C or less, 375°C or less, 350°C or less, 325°C or less, 300°C or less, 275°C or less, or 250°C or less. Since the lower the insulation temperature, the better, the lower limit thereof is not particularly limited, but may be, for example, 90°C or more, 100°C or more, 110°C or more, or 120°C or more.

[0055] The above-described heat-absorbing pad can exhibit excellent structural stability against flames. In one example, after irradiating the heat-absorbing pad with flames for 10 minutes, the pad's structure did not collapse, resulting in flames appearing in the opposite direction, or any portion of the pad's structure deforming to a temperature exceeding 660°C.

[0056] In one example, the temperature of the heat transfer delay of the heat absorbing pad may be 50°C or higher. The temperature of the heat transfer delay may be, for example, 60°C or higher, 70°C or higher, 80°C or higher, 90°C or higher, 100°C or higher, 110°C or higher, 120°C or higher, 130°C or higher, 140°C or higher, 150°C or higher, 160°C or higher, 170°C or higher, 180°C or higher, or 190°C or higher. The lower limit of the above thermal transfer delay temperature may be, for example, 300°C or less, 260°C or less, 240°C or less, 220°C or less, 200°C or less, 190°C or less, 180°C or less, 170°C or less, 160°C or less, 150°C or less, 140°C or less, 130°C or less, 120°C or less, 110°C or less, or 100°C or less. The above thermal transfer delay temperature may mean a part of the temperature in the thermal transfer delay section (for example, the temperature at the start time and / or the temperature at the end time of the thermal transfer delay section), or may mean the temperature in the entire time of the thermal transfer delay section. When the thermal transfer delay temperature is within the above range, it may be appropriate to delay rapid ignition by flame at the beginning by absorbing the initial heat generation amount when the battery cell explodes.

[0057] In one example, the heat transfer delay time of the heat absorption pad may be, for example, 5 seconds or longer. The heat transfer delay time may be 10 seconds or longer, 20 seconds or longer, 30 seconds or longer, 40 seconds or longer, 60 seconds or longer, 80 seconds or longer, 100 seconds or longer, 120 seconds or longer, 140 seconds or longer, 160 seconds or longer, 180 seconds or longer, or 200 seconds or longer. The longer the heat transfer delay time is advantageous, and the upper limit thereof is not particularly limited, but may be, for example, 60 minutes or shorter.

[0058] The absorbent pad may have irreversibility in which its shape does not return to its original state after heating and cooling. In one example, the XRD (X-ray diffraction) pattern of the absorbent pad measured after heating the absorbent pad to 200°C and cooling it to room temperature may be different from the XRD (X-ray diffraction) pattern of the absorbent pad before heating. The heating of the absorbent pad to 200°C may be maintained for about 60 minutes. The absorbent pad before heating refers to the absorbent pad at room temperature without heating. The room temperature may be, for example, in the range of 20°C to 30°C or about 25°C. If the absorbent pad does not have the irreversibility, the XRD patterns before and after heating may be the same. Specifically, when an XRD analysis is performed on a heat-absorbing pad, a graph can be obtained in which the x-axis is 2θ (2 Theta) and the y-axis is intensity (au) (θ is the incident angle of the diffracted X-ray, and intensity is the intensity of the diffracted X-ray). Multiple diffraction peaks appear in the graph, and a pattern can be obtained from these. Different XRD patterns may mean that at least one of the multiple diffraction peaks does not appear. Identical XRD patterns may mean that the multiple diffraction peaks appear identically.

[0059] In one example, the thickness of the heat-absorbing pad may be, for example, 0.5 mm or more. Specifically, the thickness of the heat-absorbing pad may be 1 mm or more, 1.5 mm or more, 2 mm or more, 2.5 mm or more, or 3 mm or more. When the thickness of the heat-absorbing pad is within the above range, it may be advantageous in improving heat absorption performance and exhibiting excellent heat transfer delay characteristics. The upper limit of the thickness of the heat-absorbing pad may be appropriately adjusted in consideration of the battery module to which the pad is to be applied, and may be, for example, 10 mm or less, 9 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, 5 mm or less, 4 mm or less, or 3 mm or less. In one example, the thickness of the pad may be less than 4 mm, 3.5 mm or less, 3.0 mm or less, 2.5 mm or less, or 2.0 mm or less. When the thickness of the pad is within the above range, it may be more advantageous in that it may exhibit a secondary temperature delay section.

[0060] The present application relates to the use of the resin composition and / or pad. In one example, the present application relates to a battery module comprising the resin composition and / or the pad. The present application also relates to a battery pack cover comprising the resin composition and / or the pad. The battery module or battery pack cover may comprise the resin composition in a cured state (i.e., a cured product of the resin composition).

[0061] The battery module may include a module case and battery cells. The battery cells may be housed within the module case. One or more battery cells may be present within the module case, and multiple battery cells may be housed within the module case. The number of battery cells housed within the module case is not particularly limited and may be adjusted depending on the purpose, etc. The battery cells housed within the module case may be electrically connected to each other. The type of battery cells housed within the module case is also not particularly limited, and various known battery cells may be applied. In one example, the battery cell may be pouch-type. A pouch-type battery cell may typically include an electrode assembly, an electrolyte, and a pouch outer material.

[0062] The module case may include at least a side wall and a bottom plate forming an internal space in which battery cells can be accommodated. In addition, the module case may further include an upper plate sealing the internal space. The side wall, the bottom plate, and the upper plate may be formed integrally with each other, or the module case may be formed by assembling separate side walls, bottom plates, and / or upper plates. The shape and size of the module case are not particularly limited and may be appropriately selected depending on the intended use or the shape and number of battery cells accommodated in the internal space. The terms upper plate and lower plate as used above are relative terms used to distinguish between at least two plates constituting the module case. In other words, it does not mean that the upper plate must be located at the upper side and the lower plate must be located at the lower side in an actual use state.

[0063] The resin composition and / or pad may be present on one side of the battery cell. When the battery module includes a plurality of battery cells, the resin composition and / or pad may be positioned between the battery cells. The resin composition and / or pad maintains its original shape without any change in state at the operating temperature of the battery, but when thermal runaway occurs, the resin composition and / or pad may provide a cooling effect to the ignition cell through a change in state and delay the transfer of heat to adjacent cells.

[0064] The heat-absorbing pad of the present invention can exhibit excellent heat transfer delay characteristics and form a carbon film against a flame to exhibit a uniform thermal insulation temperature. The heat-absorbing pad can be usefully used to delay heat transfer to adjacent battery cells during thermal runaway of a battery cell.

[0065] Hereinafter, the present application will be described in detail through examples according to the present application, but the scope of the present application is not limited by the examples presented below.

[0066] Example 1

[0067] In the container of a paste mixer (Daehwa Tech, PDM-1K equipment), 88.7 parts by weight of silicone resin (VP1000, Damie Polychem) and 11.3 parts by weight of curing agent (Andisil XL12, AB Specialty Silicones) were added to make 100 parts by weight of binder resin. For 100 parts by weight of binder resin, 150 parts by weight of boric acid particles (Daejung Chemicals) as heat-absorbing particles, 70 parts by weight of aluminum diethyl phosphinate particles (FR-119L, Kempia) as flame retardant particles, and 1.1 parts by weight of dispersant (LP X 21879, BYK) were added and mixed at a revolution of 600 rpm and a rotation of 200 rpm for 2 minutes. After confirming that the mixture was uniform, the particles were degassed for the first time and mixed at a revolution of 600 rpm and a rotation of 200 rpm for 2 minutes. Afterwards, 0.2 parts by weight of a curing catalyst (SRX-212, Dow) was added, secondary defoaming was performed, and the mixture was mixed for 2 minutes at a revolution of 600 rpm and a rotation of 200 rpm to prepare a resin composition.

[0068] A frame-shaped silicone dam (the overall size of the dam is 12 cm x 12 cm (width x height), the internal size of the dam is 10 cm x 10 cm (width x height), and the height of the dam is 2 mm) was prepared on a fluorine release coating paper. The resin composition was applied inside the silicone dam and then covered with a fluorine release coating paper. The fluorine release coating paper was pressed with a glass plate and left at room temperature (25°C) for 24 hours to harden, thereby producing a pad with a uniform thickness (2 mm).

[0069] Example 2

[0070] A heat-absorbing pad was manufactured in the same manner as Example 1, except that 70 parts by weight of aluminum diethyl phosphinate particles (FR-33, Kempia) were used as flame retardant particles.

[0071] Example 3

[0072] A heat-absorbing pad was manufactured in the same manner as Example 1, except that 70 parts by weight of aluminum diethyl phosphinate particles (624E, Kempia) were used as flame retardant particles.

[0073] Example 4

[0074] In the container of a paste mixer (Daehwa Tech, PDM-1K equipment), 50 parts by weight of silicone resin (VP1000, Damie Polychem), 11.3 parts by weight of curing agent (Andisil XL12, AB Specialty Silicones), and 38.7 parts by weight of chain extender (CE-500, AB Specialty) were added to make 100 parts by weight of binder resin. For 100 parts by weight of binder resin, 150 parts by weight of boric acid particles (Daejung Chemicals) as heat-absorbing particles, 40 parts by weight of ammonium phosphate particles (624E, Kempia) as flame retardant particles, 70 parts by weight of aluminum hydroxide particles (H-WF-1, Chalco), and 1.3 parts by weight of dispersant (LP X 21879, BYK) were added and mixed at a revolution of 600 rpm and a rotation of 200 rpm for 2 minutes. After confirming that a uniform mixture was achieved, the particles were defoamed for the first time and mixed for 2 minutes at 600 rpm and 200 rpm. Afterwards, 0.2 parts by weight of a curing catalyst (SRX-212, Dow) was added and defoamed for the second time, and the mixture was mixed for 2 minutes at 600 rpm and 200 rpm, thereby preparing a resin composition.

[0075] A frame-shaped silicone dam (the overall size of the dam is 12 cm x 12 cm (width x height), the internal size of the dam is 10 cm x 10 cm (width x height), and the height of the dam is 2 mm) was prepared on a fluorine release coating paper. The resin composition was applied inside the silicone dam and then covered with a fluorine release coating paper. The fluorine release coating paper was pressed with a glass plate and left at room temperature (25°C) for 24 hours to harden, thereby producing a pad with a uniform thickness (2 mm).

[0076] Example 5

[0077] A heat-absorbing pad was manufactured in the same manner as Example 4, except that 40 parts by weight of ammonium phosphate particles (624X, Kempia) and 70 parts by weight of aluminum hydroxide particles (H-WF-1, Chalco) were used as flame retardant particles.

[0078] Example 6

[0079] In the container of a paste mixer (Daehwa Tech, PDM-1K equipment), 88.7 parts by weight of silicone resin (VP1000, Damie Polychem) and 11.3 parts by weight of curing agent (Andisil XL12, AB Specialty Silicones) were added to make 100 parts by weight of binder resin. For 100 parts by weight of binder resin, 100 parts by weight of magnesium phosphate (Daejung Chemicals & Metals) as heat-absorbing particles, 40 parts by weight of 624E as flame retardant particles, 70 parts by weight of aluminum hydroxide (H-WF-1), and 1.1 parts by weight of dispersant (LP X 21879, BYK) were added and mixed at a revolution of 600 rpm and a rotation of 200 rpm for 2 minutes. After confirming that the mixture was uniform, the particles were degassed for the first time and mixed at a revolution of 600 rpm and a rotation of 200 rpm for 2 minutes. Afterwards, 0.2 parts by weight of a curing catalyst (SRX-212, Dow) was added, secondary defoaming was performed, and the mixture was mixed for 2 minutes at a revolution of 600 rpm and a rotation of 200 rpm to prepare a resin composition.

[0080] A frame-shaped silicone dam (the overall size of the dam is 12 cm x 12 cm (width x height), the internal size of the dam is 10 cm x 10 cm (width x height), and the height of the dam is 2 mm) was prepared on a fluorine release coating paper. The resin composition was applied inside the silicone dam and then covered with a fluorine release coating paper. The fluorine release coating paper was pressed with a glass plate and left at room temperature (25°C) for 24 hours to harden, thereby producing a pad with a uniform thickness (2 mm).

[0081] Comparative Example 1

[0082] A heat-absorbing pad was manufactured in the same manner as Example 1, except that flame retardant particles were not used in the manufacture of the resin composition and 245 parts by weight of heat-absorbing particles were used.

[0083] Comparative Example 2

[0084] A heat-absorbing pad was manufactured in the same manner as Example 1, except that 70 parts by weight of zinc hydroxy stannate particles (ZHS, Shinsung Hichem Co., Ltd.) were used as flame retardant particles.

[0085] Comparative Example 3

[0086] A heat-absorbing pad was manufactured in the same manner as Example 1, except that 70 parts by weight of particles containing a mixture of phosphorus and nitrogen (FR-PPZ, Kempia) as flame retardant particles were used.

[0087] Comparative Example 4

[0088] A heat-absorbing pad was manufactured in the same manner as in Example 1, except that 70 parts by weight of low Br flame retardant particles (FR-8000, Kempia) containing a mixture of phosphorus, nitrogen, and bromine were used.

[0089] Comparative Example 5

[0090] A heat-absorbing pad was manufactured in the same manner as Example 1, except that 70 parts by weight of melamine cyanurate particles (FR-MCA, Kempia) were used as flame retardant particles.

[0091] Example 7

[0092] In the container of a paste mixer (Daehwa Tech, PDM-1K equipment), 68 parts by weight of silicone resin (VP10000, Damie Polychem) and 32 parts by weight of hardener (Andisil XL12, AB Specialty Silicones) were added to make 100 parts by weight of binder resin. For 100 parts by weight of binder resin, 125 parts by weight of boric acid particles (Daejung Chemicals & Metals Co., Ltd.), 40 parts by weight of APP (Ammonium Phosphate) (FR-624E, Kempia) as flame retardant particles, 20 parts by weight of aluminum hydroxide particles (HWF-20, Chalco Co., Ltd.), 0.9 parts by weight of dispersant (LP X 21879, BYK Co., Ltd.), 0.8 parts by weight of curing retardant (VMC, HRS Co., Ltd.), 26 parts by weight of hexane solvent (Daejung Chemicals & Metals Co., Ltd.), and 0.4 parts by weight of catalyst (SRX-212, Dow Co., Ltd.) were added, and then the mixture was mixed for 1 minute at a revolution of 600 rpm and a rotation of 500 rpm to prepare a compounding solution. After placing a fluorine release film on an automatic coating device, the coating gap was adjusted, and the compounding solution was poured onto the fluorine release film and coated. Next, a foam pad was manufactured by drying in a Matisse oven at 130°C for 10 minutes. The thickness of the manufactured foam pad was approximately 2 mm.

[0093] Example 8

[0094] An absorbent foam pad was manufactured in the same manner as in Example 7, except that the thickness of the foam pad was changed to 2.8 mm.

[0095] Example 9

[0096] An absorbent foam pad was manufactured in the same manner as in Example 7, except that the thickness of the foam pad was changed to 3.0 mm.

[0097] Example 10

[0098] An absorbent foam pad having a thickness of approximately 2.0 mm was manufactured in the same manner as Example 7, except that 150 parts by weight of boric acid particles (Daejung Chemical Co., Ltd.) were used as absorbent particles.

[0099] Example 11

[0100] An absorbent foam pad having a thickness of approximately 2.0 mm was manufactured in the same manner as Example 8, except that 180 parts by weight of boric acid particles (Daejung Chemical Co., Ltd.) were used as absorbent particles.

[0101] Example 12

[0102] An absorbent foam pad having a thickness of approximately 2.0 mm was manufactured in the same manner as in Example 7, except that 40 parts by weight of ammonium phosphate particles (FR-624E, Kempia), 20 parts by weight of aluminum hydroxide particles (HWF-20, Chalco), and 20 parts by weight of ammonium phosphate particles (APP 422, Clariant Korea) were used as flame retardant particles.

[0103] Example 13

[0104] An absorbent foam pad having a thickness of approximately 2.0 mm was manufactured in the same manner as Example 7, except that 40 parts by weight of ammonium phosphate particles (FR-624E, Kempia), 20 parts by weight of aluminum hydroxide particles (HWF-20, Chalco), and 20 parts by weight of ammonium phosphate particles (APP 462, Clariant Korea) were used as flame retardant particles.

[0105] Example 14

[0106] An absorbent foam pad having a thickness of approximately 2.0 mm was manufactured in the same manner as in Example 7, except that 125 parts by weight of ammonium borate octahydrate particles (Wako Pure Chemical) were used as absorbent particles.

[0107] Comparative Example 6

[0108] A pad (LGC) having a polyurethane foam layer with a thickness of approximately 2.0 mm formed on a PET film was prepared as Comparative Example 6. The polyurethane foam pad of Comparative Example 6 did not contain heat-absorbing particles.

[0109] Comparative Example 7

[0110] A silicone foam pad (L2Y) with a thickness of approximately 2.0 mm was prepared as Comparative Example 7. The silicone foam pad of Comparative Example 7 does not contain heat-absorbing particles and contains a flame retardant (aluminum hydroxide).

[0111] Comparative Example 8

[0112] An absorbent foam pad having a thickness of approximately 2.0 mm was manufactured in the same manner as Example 6, except that 280 parts by weight of boric acid particles (Daejung Chemical Co., Ltd.) were used as absorbent particles and flame retardant particles were not used.

[0113] Comparative Example 9

[0114] An absorbent foam pad having a thickness of approximately 2.0 mm was manufactured in the same manner as Example 6, except that 180 parts by weight of boric acid particles (Daejung Chemicals Co., Ltd.) were used as absorbent particles, and only 20 parts by weight of aluminum hydroxide particles (HWF-20, Chalco Co., Ltd.) were used as flame retardant particles.

[0115] Comparative Example 10

[0116] An absorbent foam pad having a thickness of approximately 2.0 mm was manufactured in the same manner as Example 6, except that 180 parts by weight of boric acid particles (Daejung Chemicals Co., Ltd.) were used as absorbent particles, and only 20 parts by weight of magnesium hydroxide particles (Sigma-Aldrich Co., Ltd.) were used as flame retardant particles.

[0117] Comparative Example 11

[0118] A resin composition was prepared in the same manner as in Example 1, except that 100 parts by weight of binder resin, 40 parts by weight of polyol (Capa2043, Perstorp) with a molecular weight of 400 g / mol as a main resin, and 60 parts by weight of HDI trimer (Tolonate HDT LV2, Vencorex) as a curing agent were used. Thereafter, the resin composition was cured in the same manner as in Example 1. In the case of Comparative Example 11, the isocyanate portion of the curing agent reacted with the endothermic particles, making it impossible to manufacture it in the form of a pad.

[0119] Comparative Example 12

[0120] A resin composition was prepared in the same manner as in Example 1, except that 100 parts by weight of binder resin was used, 55 parts by weight of epoxy resin (PG-207P, Kukdo Chemical Co., Ltd.) with a molecular weight of 640 g / mol as a main resin, and 45 parts by weight of an amine-based compound (Jeffamine D-400, Huntsman Co., Ltd.) as a curing agent. Thereafter, the resin composition was cured in the same manner as in Example 1. In the case of Comparative Example 12, the amine portion of the curing agent reacted with the endothermic particles, making it impossible to manufacture it in the form of a pad.

[0121] Comparative Example 13

[0122] A resin composition was prepared in the same manner as in Example 6, except that 100 parts by weight of binder resin, 40 parts by weight of polyol (Capa2043, Perstorp) with a molecular weight of 400 g / mol as a main resin, and 60 parts by weight of HDI trimer (Tolonate HDT LV2, Vencorex) as a curing agent were used. Thereafter, the resin composition was cured in the same manner as in Example 6. In the case of Comparative Example 13, the isocyanate portion of the curing agent reacted with the endothermic particles, making it impossible to manufacture it in the form of a pad.

[0123] Comparative Example 14

[0124] A resin composition was prepared in the same manner as in Example 6, except that 100 parts by weight of binder resin was used, 55 parts by weight of epoxy resin (PG-207P, Kukdo Chemical Co., Ltd.) with a molecular weight of 640 g / mol as a main resin, and 45 parts by weight of an amine-based compound (Jeffamine D-400, Huntsman Co., Ltd.) as a curing agent. Thereafter, the resin composition was cured in the same manner as in Example 6. In the case of Comparative Example 14, the amine portion of the curing agent reacted with the endothermic particles, making it impossible to manufacture it in the form of a pad.

[0125] Evaluation Example 1. Evaluation of heat transfer delay characteristics and insulation characteristics

[0126] The pads of the examples and comparative examples were cut into 6 cm x 6 cm (width x length) and prepared as samples. SUS frames were attached to the front and back of the samples. The SUS frame has an overall size of 6 cm x 6 cm (width x length) and a 5 cm x 5 cm (width x length) hole, so the area where the flame actually touches the pad or sheet is 5 cm x 5 cm (width x length). The SUS frame prevents the sample from being bent by the flame. The pad with the SUS frame attached was vertically clamped to a jig (the main surface of the pad was perpendicular to the ground, and the thickness direction of the pad was parallel to the ground). An LPG gas torch (LPG gas: Sun Lighter Gas, Taeyang Industry Co., Ltd., gas torch: 500JET, Honest Co., Ltd.) was placed on the first main surface side of the pad, and a thermal imaging camera (A655SC, FLIR Co., Ltd.) was placed on the second surface side of the pad opposite the first main surface. The pixel resolution of the above thermal imaging camera is 640×480, and the upper limit of the measured temperature is 660℃. The part from which the flame of the gas torch was emitted was positioned at the center of the first main surface of the pad, and the lens of the thermal imaging camera was positioned at the center of the second main surface of the pad. In addition, the distance between the first main surface of the pad and the part from which the flame of the gas torch was emitted was approximately 3 cm, and the distance between the second main surface of the pad and the lens of the thermal imaging camera was 40 cm. The ambient temperature before the flame was emitted from the gas torch was approximately 25℃. The temperature of the second main surface was measured using the thermal imaging camera while the flame was emitted from the torch for approximately 3 minutes to heat the pad. The thermal imaging camera measures the infrared radiation emitted by the pad and calculates the temperature based on the measured infrared radiation value. The temperature measured by the thermal imaging camera is the temperature at the highest temperature point of the pad.

[0127] As described above, when a flame is applied to a sample, if the sample absorbs heat and the temperature is maintained for a certain period of time without increasing, it is evaluated as having a heat transfer delay effect. Specifically, a continuous section in which the temperature change is 5℃ or less in a graph of the temperature (℃) of the pad against the measured time (second) when a flame is applied to the sample can be defined as a heat transfer delay section. The temperature change of 5℃ or less means that the temperature increase per second within the section is 5℃ or less. More specifically, the temperature change of 5℃ or less may mean that, when times t1 and t2 are selected at 1-second intervals within the section (t1-t2=1 second), the absolute value of the difference between the temperature T1 at t1 and the temperature T2 at t2 is 5℃ or less (the absolute value of T1-T2≤5℃). The continuous section may mean that the absolute values ​​of all T1-T2 within the section are 5℃ or less. The temperature at the end point of the above heat transfer delay section is referred to as the heat transfer delay temperature, and the time for which the above heat transfer delay section is maintained is referred to as the heat transfer delay time, as shown in Tables 2 and 3 below.

[0128] In addition, the temperature of the second main surface of the pad was measured after irradiating the flame to the first main surface of the pad for 3 or 10 minutes by a gas torch, and the temperature was taken as the adiabatic temperature. For Examples 1 to 6 and Comparative Examples 1 to 5, the adiabatic temperature was measured after irradiating the flame for 3 minutes, and for Examples 7 to 14 and Comparative Examples 6 to 10, the adiabatic temperature was measured after irradiating the flame for 10 minutes. When the adiabatic temperature was less than 500°C, it was evaluated as ○ in Tables 2 and 3, and when the adiabatic temperature was 500°C or higher, it was evaluated as × in Tables 2 and 3.

[0129] Evaluation Example 2. Density Measurement

[0130] The pads of the examples and comparative examples were cut into a size of 3 cm x 3 cm in width x length and prepared as samples, and the thickness (cm) and weight (g) were measured. Density (g / cm) 3 ) was calculated from weight (g) / (width (cm) × length (cm) × thickness (cm)).

[0131] Evaluation Example 3. Compression ratio measurement

[0132] The pads of the examples and comparative examples were cut into a size of 30 mm × 30 mm (width × length) and prepared as samples, and their thicknesses were measured. A circular jig with a diameter of 6.5 mm was installed using TA (Texture Analyzer.XT.plus-EXPONENT) equipment, and a flat fixed jig was prepared below. The sample was placed on the flat jig below, and the circular jig installed above was positioned close to the sample, and then a compression test was performed. The compression test was performed at 25℃ and 50% RH (relative humidity). The detailed conditions of the compression test were as follows: Test Mode = Compression, Test speed = 0.05 mm / s, Target Distance = a value calculated as 90% of the measured sample thickness, and Trigger force = 3 g. From the compression test, a graph was obtained in which the x-axis represents distance (mm) and the y-axis represents force (g). In the graph, the part where the sample measurement started was set as 0% as the standard, and a value between 1% and 25% of the strain was taken. TA compression ratio is measured by looking at the slope of the graph (the slope of the graph connecting the values ​​of 1% strain and 25% strain with a straight line), and the unit is g / mm.

[0133] Evaluation Example 4. Flexibility Evaluation

[0134] The pads of the examples and comparative examples were cut to a size of 50 mm x 100 mm in length x width and prepared as samples. When the sample was rolled into a roll (a circular jig made of SUS material with a diameter of approximately 6.5 mm) and then unfolded, if there were wrinkles or the pad was destroyed, it was evaluated as having no flexibility (X). If the pad was unfolded well to its original state without tearing, it was evaluated as having flexibility (O). The results are shown in Tables 2 and 3.

[0135] Evaluation Example 5. Evaluation of the presence / absence of cracks and carbon film

[0136] After setting as in Evaluation Example 1, the presence or absence of cracks and carbonized films was evaluated while emitting a flame toward the first main surface of the pad with a gas torch, and the results are shown in Tables 2 and 3. The presence or absence of carbonized films was visually observed at 3, 5, and 10 minutes after the flame emitting, respectively. If the film was pierced or melted after the flame emitting, it was evaluated that a crack existed, and if a thin film that was not pierced after the flame emitting but was discolored by the flame existed, it was evaluated that a carbonized film was formed.

[0137] Evaluation Example 6. Flame retardancy evaluation

[0138] The pads of the examples and comparative examples were tested for flammability according to the UL 94 standard. First, five test specimens were prepared by cutting them into a size of width × length × thickness = 12~13mm × 10~13cm × 2mm. After exposing one specimen to fire for about 5 seconds, the time until the fire went out was checked (t1). If the fire went out, a second exposition was performed and the time until the fire went out was checked (t2). It was checked whether the sum of t1 and t2 was within 10 seconds for one sample and within 50 seconds for a total of 5 samples, and whether the fire went up to the end of the sample and burned. According to the standard conditions of Table 1, the V0, V1, and V2 grades were assigned, and the results are shown in Tables 2 and 3 below.

[0139] Specification Conditions V0 V1 V2 Individual afterburning time (t1 or t2) ≤10 sec ≤30 sec ≤30 sec Total afterburning time (t1+t2) ≤50 sec ≤250 sec ≤250 sec Time for combustion and spark formation after secondary contact (t2+t3) ≤30 sec ≤60 sec ≤60 sec Combustion to the 125 mm mark No No No Ignition of cotton by dropping No No Yes

[0140] - t1: Afterburn time after first contact (sec)

[0141] - t2: Afterburn time after second contact (sec)

[0142] - t3: Residual shock time after second contact (sec)

[0143] Heat transfer delay effectHeat transfer delay time (sec)Heat transfer delay temperature (℃)Insulation temperature 3 minutes after flame (Less than 500℃: ○, More than 500℃: ×)Crack oil / Non-carbonized film oil / Non-flame retardantExample 1○69172○×○V0Example 2○51174○×○V0Example 3○51168○×○V0Example 4○61158○×○V0Example 5○79163○×○V0Example 6○40214○×○V0Comparative example 1○42158×○×V2Comparative example 2○26158×○×V0Comparative example 3○25157×○×V0Comparative example 4○26159×○×V0Comparative example 5○33161×○×V0

[0144] Heat transfer delay effect Heat transfer delay time (sec) Heat transfer delay temperature (℃) Flame 10 minutes later Adiabatic temperature (Less than 500℃: ○, More than 500℃: ×) Density (g / cm) 3)TA Compression ratio (g / mm) Crack oil / non-carbonized film oil / non-flame retardant Example 7○26159○0.6221440×○V0 Example 8○51155○0.557800×○V0 Example 9○70162○0.540637×○V0 Example 10○31162○0.6702450×○V0 Example 11○37161○0.6922750×○V0 Example 12○27164○0.5951600 ×○V0Example 13○30165○0.6481900×○V0Example 14○24166○0.7001450×○V0Comparative Example 6××××0.300100○×V2Comparative Example 7××××0.360600○×V0Comparative Example 8○16162×0.6061800○×V1Comparative Example 9○29158×0.8404500○×V0Comparative Example 10○20168×0.6652550○×V0

Claims

1. A heat-absorbing pad comprising a silicone resin, a heat-absorbing material, and a phosphorus-based flame retardant, which forms a carbon film against a flame and exhibits an insulation temperature of less than 500°C.

2. In the first paragraph, the heat absorbing material is a heat absorbing pad that exists in a solid state at room temperature and has the property of undergoing a phase change from solid to liquid at a temperature below 200°C.

3. A heat absorbing pad in accordance with paragraph 1, wherein the heat absorbing material is contained in an amount of 50 to 1000 parts by weight based on 100 parts by weight of the silicone resin.

4. A heat absorbing pad further comprising a metal hydroxide as a flame retardant in the first paragraph.

5. A heat absorbing pad in accordance with paragraph 1, wherein the phosphorus flame retardant is included in an amount of 10 to 100 parts by weight per 100 parts by weight of the heat absorbing material.

6. In the first paragraph, the heat absorbing pad is a heat absorbing pad that exhibits a heat transfer delay temperature within a range of 50°C to 300°C with respect to a flame.

7. In the first paragraph, the heat-absorbing pad is a heat-absorbing pad having a heat transfer delay time of 10 seconds or more.

8. In the first paragraph, the heat-absorbing pad is a heat-absorbing pad that does not have a porous structure.

9. In the first paragraph, the heat-absorbing pad has a porous structure and a density of 1 g / cm 3 Below is the heat absorbing pad.

10. In the first paragraph, the heat absorbing pad has a thickness in the range of 0.1 mm to 10 mm.

Images