Composite material

Abstract

Disclosed in the present specification are a composite material, a heat absorbing device, a method for manufacturing same, a use of the composite material, and the like. The composite material and the like is applied to products or devices that generate heat or are likely to ignite or explode during operation, storage, and / or maintenance, and thus can effectively respond to the heat, ignition, and explosion. For example, the composite material and the like are applied to an article including a plurality of the products or devices, to respond to abnormal heat generation, explosion and ignition that occur in any one of the devices or products, and can prevent or minimize the propagation of the heat generation, explosion and ignition to other adjacent devices or products.

Description

composite materials

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2024-0103468, filed with the Korean Intellectual Property Office on August 2, 2024, and Korean Patent Application No. 10-2024-0142391, filed with the Korean Intellectual Property Office on October 17, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present specification discloses a composite material, a heat absorbing device comprising the composite material, and uses of the composite material and the heat absorbing device.

[0003] The importance of technology to manage heat generated from products is increasing, but it is a difficult problem to manage, control, and manage heat in products composed of multiple heat-generating elements (heat-generating elements).

[0004] For example, it is very important to prevent the so-called TR (Thermal Runaway) or TP (Thermal Propagation) phenomenon that occurs in battery modules or battery packs. A battery module or battery pack includes multiple battery cells or multiple battery modules, which are positioned relatively adjacent to each other. In such a structure, the phenomenon in which abnormal heat generation, ignition, and / or explosion occurring in one battery cell and / or battery module is transmitted in a chain reaction to other adjacent battery cells is called the TR or TP phenomenon. The chain reaction of ignition or explosion caused by this TR or TP phenomenon must be managed from a safety perspective.

[0005] The present specification discloses composite materials, heat absorbing devices, and their uses. The purpose of the present specification is to disclose composite materials and heat absorbing devices that can be applied to products or components that have the potential for abnormal heat generation, ignition, and / or explosion during operation, storage, and / or maintenance, thereby effectively counteracting such heat generation, ignition, and explosion.

[0006] For example, the composite materials and heat absorbing devices disclosed herein can be applied to articles comprising multiple of the above products or elements to respond to abnormal heat generation, explosion, and / or ignition occurring in one of the elements or products, and prevent or minimize the spread of such heat generation, explosion, and / or ignition to other adjacent elements or products.

[0007] The present specification also aims to disclose a composite material and a heat absorbing device having excellent handling and storage stability. The present specification also aims to disclose uses of the composite material and the heat absorbing device.

[0008] Among the properties mentioned in this specification, properties that are affected by temperature are properties measured at room temperature, unless otherwise specified.

[0009] The term room temperature means a natural temperature that has not been artificially heated or cooled, for example, a temperature within the range of about 10°C to 30°C, for example, a temperature of about 23°C or about 25°C.

[0010] The unit of temperature referred to in this specification is Celsius (℃), unless otherwise specified.

[0011] Among the properties mentioned in this specification, properties affected by pressure are properties measured at atmospheric pressure, unless otherwise specified.

[0012] The term atmospheric pressure refers to natural pressure that has not been artificially pressurized or depressurized, and is usually a pressure in the range of about 700 mmHg to 800 mmHg.

[0013] Among the properties mentioned in this specification, properties affected by humidity are properties measured at room temperature and pressure without artificially controlling humidity, unless otherwise specified.

[0014] The present specification discloses a composite material.

[0015] The term composite refers to a material containing two or more components.

[0016] The above composite material may include an inorganic gel.

[0017] The present specification also discloses a heat absorbing device comprising the composite material.

[0018] The above heat absorbing device may include a case having a sealed space inside and a composite material existing in the sealed space inside.

[0019] The case is a container for holding the composite material. The case has a sealed space inside. The case having a sealed space inside means that the sealed space is formed inside the case, or that a certain space exists inside the case, and although the space is not sealed, the case exists so that the sealed space can be formed by sealing the open portion.

[0020] The term "abnormal condition" as used herein refers to a condition in which abnormal heat generation, ignition and / or explosion occurs during the operation, storage and / or maintenance of any product or component, or in which there is a possibility of such abnormal heat generation, ignition and / or explosion occurring.

[0021] In this specification, the term normal state refers to the normal operation, storage and / or maintenance state of any product or device other than the above abnormal state.

[0022] The above-mentioned sealed space refers to a space formed so that the components of the composite material, etc., do not substantially leak out to the outside under normal conditions. In one example, the case may have a WVTR (Water Vapor Transmission Rate) within a predetermined range described below, and the sealed space may be substantially entirely surrounded by a case having the WVTR (Water Vapor Transmission Rate).

[0023] The above-mentioned sealed space has a vent area. The term "vent area" may refer to an area that exists to maintain a sealed state under normal conditions, but is opened under abnormal conditions to allow the discharge of substances within the space. Such a vent area may be formed in the manner described below.

[0024] In one example, the case may have a water vapor transmission rate (WVTR) within a predetermined range. For example, at least a portion of the case forming the sealed space may have a water vapor transmission rate (WVTR) within a predetermined range. For example, the upper limit of the WVTR of the above case may be about 10, 9.5, 9, 8.5, 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.05, 0.01, 0.005, or 0.001, and the lower limit may be about 0, 0.1, 0.2, 0.3, 0.4, or 0.5. The WVTR is within a range that is less than or equal to any one upper limit arbitrarily selected from the upper limits listed above; Or, it may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. By having such a WVTR, storage stability for a substance existing inside the sealed space can be secured, and the heat absorbing device can more efficiently exhibit the intended extinguishing or heat absorbing action. The unit of the WVTR (Water Vapor Transmission Rate) is g / m 2· The above WVTR is evaluated according to the standard of ASTM F1249 under the conditions of 38℃ and 100% relative humidity.

[0025] The above-mentioned heat absorbing device is configured to maintain a vaporizable substance contained in the composite material in the sealed space in a normal state and to release the vaporizable substance or its vaporized substance to the outside in an abnormal state.

[0026] This action is explained assuming that the above heat absorbing device is applied to a battery module.

[0027] Fig. 1 is a schematic diagram of a case where the heat absorption device (S) is applied to a battery module. As shown in Fig. 1, the battery module can be configured by arranging a plurality of battery cells (11, 12, 13, 14, 15, 16) adjacent to each other, and the heat absorption device (S) can be arranged between battery cells (for example, between 12 and 13 and / or between 14 and 15 in Fig. 1).

[0028] The above heat absorbing device (S) maintains volatile substances, etc., inside it in a normal state. When an abnormal state occurs, the internal substance of the heat absorbing device (S) is ejected through the vent area (dashed arrow in Fig. 1), and the internal substance ejected in this way can respond to heat generation and / or flames, etc. in the abnormal state. In Fig. 1, a case is described where the internal substance is ejected from both the upper and lower directions of the heat absorbing device (S), but the direction of the ejection is not limited to Fig. 1. The direction of the ejection may be one direction of the heat absorbing device (S), or may be two or more directions.

[0029] In order for the heat absorbing device to effectively perform the above function in an abnormal state, it is required that the volatile substances existing inside the case in a normal state be stably maintained, that the internal substances be able to be quickly discharged to the outside when an abnormal state occurs, and that the volatile substances existing inside the case in an abnormal state be able to be discharged to the outside in a vaporized state as much as possible so that they are consumed.

[0030] For the heat absorbing device to effectively perform the above function under ideal conditions, the vaporization rate of the vaporizable substance must be maintained appropriately. If the vaporizable substance vaporizes at an appropriate rate, the pores of the internal inorganic gel can be prevented from collapsing due to changes in surface tension, etc. following heat absorption by the vaporizable substance.

[0031] The heat absorbing device disclosed in this specification can satisfy the above requirements.

[0032] The above-mentioned heat absorbing device explains the principle by which the above-mentioned function is performed.

[0033] Fig. 2 shows only the heat absorbing device (S) in Fig. 1 separately. In a configuration such as Fig. 1, if abnormal heating, abnormal ignition, and / or abnormal explosion occurs in at least one of the battery cells adjacent to the heat absorbing device (S), a certain level of heat or more is instantaneously applied to the heat absorbing device, as indicated by the solid arrow in Fig. 2. In the sealed space inside the case (1001) of the heat absorbing device in Fig. 2, as indicated by the dotted arrow, volatile substances are randomly propagated in all directions within the space. At this time, if the WVTR of the portion forming the sealed space of the case (1001) is within the aforementioned range, the vaporized gas cannot be released to the outside, and therefore, the inside of the case (1001) becomes very high-pressure. At this time, when the vent area (1002) of the case is configured to open instantaneously at a high pressure above a certain level, the vent area (1002) is opened instantaneously at the high pressure state, and the gas inside is quickly discharged to the outside through the opened vent area (1002).

[0034] When the WVTR of the case is high, the pressure inside the case (1001) may not effectively increase in an abnormal state, so that the vent area (1002) may not be opened effectively, or even when the vent area (1002) is opened, the internal pressure may not sufficiently increase, so that the internal gas may not be completely discharged to the outside and exhausted, or the discharge speed may not be properly secured.

[0035] By keeping the WVTR of the case low, the storage stability of the internal material under normal conditions can also be effectively secured.

[0036] The method for forming the above-mentioned vent area (1002) is not particularly limited. The vent area can be formed by designing a certain area of ​​the case forming the sealed space to be opened when a certain level of pressure and / or heat is applied. For example, if a certain area of ​​the case forming the sealed space is configured to have lower strength than other areas, the area having the lower strength can be opened due to increased internal pressure. In addition, a method of forming the sealed space through sealing using a hot melt material or the like so that opening occurs by melting at a predetermined temperature can also be used. Alternatively, the vent area can be formed by making only a certain area of ​​the case forming the sealed space thinner than other areas. Such methods for forming the vent area can be easily adopted by those skilled in the art.

[0037] For example, when the heat absorbing device is applied to a battery module or pack, for convenience of application, the case may be a square case, pouch-shaped case, and / or cylindrical case having the same shape as the battery cell. In such cases, a vent area may also be formed by controlling the bonding strength of the cover forming a sealed space in the square or cylindrical case.

[0038] The above case can be constructed using a known material as long as it can satisfy the aforementioned WVTR, and the material can have a single-layer structure or a single-layer structure of two or more layers.

[0039] For example, the case can be formed using a material capable of exhibiting a WVTR in the above range among suitable organic and / or inorganic layers.

[0040] As the organic layer, for example, a known polymer film or sheet can be used. Examples of the organic film include a cellulose-based polymer film; a COP (cyclo olefin copolymer) film; an acrylic polymer film; a polyolefin film; a PVA (polyvinyl alcohol) film; a PVC (poly(vinyl chloride)) film, a PES (poly ether sulfone) film; a PEEK (polyetheretherketon) film; a PPS (polyphenylsulfone) film; a PEI (polyetherimide) film; a PEN (polyethylenemaphthatlate) film; a PET (poly(ethylene terephthalate)) film; a PI (polyimide) film; a PSF (polysulfone) film and / or a PAR (polyarylate) film.

[0041] For example, the inorganic layer may be a metal layer, a metal oxide layer, a metal nitride layer, or a metal oxynitride layer. For example, the inorganic layer may be a metal layer, a metal oxide layer, a metal nitride layer, or a metal oxynitride layer including at least one selected from the group consisting of In, Sn, Pb, Au, Cu, Ag, Zr, Hf, Zn, Al, Si, La, Ti, and Ni. For example, a foil, sheet, or film of the material may be applied, or a layer formed by depositing the metal layer, the metal oxide layer, the metal nitride layer, or the metal oxynitride layer on an appropriate substrate may be used.

[0042] The material forming the case may be a single layer selected from the inorganic layer and organic layer, or a multilayer structure in which two or more of the layers are laminated.

[0043] The thickness of the above-mentioned inorganic layer and / or organic layer is selected in consideration of the desired properties such as WVTR and is not particularly limited. For example, the lower limit of the thickness may be about 1, 5, 10, 15, 20, 25 or 30, and the upper limit may be about 5,000, 4,000, 3,000, 2,000, 1,000, 500, 200, 150, 100, 90, 80, 70, 60, 50, 40 or 30. The unit of the thickness is μm. The thickness is within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above. Or, it may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0044] The above heat absorbing device may include additional components to enable the above operation to be performed more effectively.

[0045] For example, the heat absorbing device may additionally include a heat conductive layer. This heat conductive layer may be located at an appropriate location within the heat absorbing device, for example, the heat conductive layer may be located between the case and the composite material described below within the heat absorbing device.

[0046] Fig. 3 is an example of a case in which the heat-conducting layer (2001) is added to the heat-absorbing device of Fig. 2. The heat-conducting layer may be located between the case (1001) and the composite material as shown in Fig. 3, but is not limited thereto in terms of location. The heat-conducting layer may be located in other locations, such as inside the case, and the number of heat-conducting layers may be one or two or more.

[0047] The term thermally conductive layer refers to a layer having a thermal conductivity (at 20°C) within the range described below. The lower limit of the thermal conductivity (at 20°C) of the thermally conductive layer may be about 15, 18, 20, 50, 100, 150, 200, 250, 300, 350, or 400, and the upper limit may be about 2,000, 1,500, 1,000, 900, 800, 700, 600, 500, 400, 300, 200, 100, or 50. The thermal conductivity is within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above; Or, it may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. The unit of the thermal conductivity is W / mK.

[0048] The type of thermally conductive layer is not particularly limited as long as it possesses the above-mentioned thermal conductivity. Typically, metal materials with excellent thermal conductivity can be used as thermally conductive layers. For example, layers made of metal materials such as aluminum, gold, pure silver, tungsten, copper, nickel, or platinum can be applied.

[0049] There is no special limitation on the thickness of the thermal conductive layer, and an appropriate thickness can be set in consideration of the specifications of the heat absorption device, etc. For example, the lower limit of the thickness of the thermal conductive layer may be about 1, 5, 10, 15, 50, 75, or 90, and the upper limit may be about 500, 400, 300, 200, 100, 50, 40, or 30. The unit of the thickness is μm. The thickness may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0050] As shown in Fig. 3, in some cases, heat generated in an abnormal state may not be uniformly applied to the heat absorber, but may be locally applied only to a certain area. However, in order for the volatile substances inside the heat absorber to quickly vaporize and achieve a high-pressure state, the heat in the abnormal state must be uniformly applied to the heat absorber. In the case where a heat conductive layer exists, even if the heat in the abnormal state is locally applied, the heat can be quickly and efficiently transferred to the entire heat absorber, thereby enabling the aforementioned extinguishing action of the heat absorber to occur quickly and efficiently.

[0051] The present specification discloses a composite material. Such a composite material may be present in a sealed space of a case of the heat absorbing device described above.

[0052] The above composite material may include an inorganic gel.

[0053] These inorganic gels can stably maintain the volatile substances described below in the composite material under normal conditions, while effectively discharging them under abnormal conditions. Furthermore, the inorganic gels exhibit appropriate buffering, insulation, and heat-insulating properties, thereby enabling the composite material and heat-absorbing device to effectively respond to abnormal conditions.

[0054] The above characteristics can be secured by controlling the material of the inorganic gel and the degree and form of gelation.

[0055] The above-mentioned inorganic gel may be, for example, an oxide network formed by a so-called sol-gel process. This oxide network may include a network in which inorganic elements are connected via oxygen atoms. As the inorganic elements, one or more selected from the group consisting of silicon, titanium, zirconium, niobium, tantalum, molybdenum, and tungsten may be exemplified. If the inorganic element is silicon, the inorganic gel may be called silica gel.

[0056] The content of the above-mentioned inorganic gel can be appropriately controlled depending on the purpose. For example, the lower limit of the content of the above-mentioned inorganic gel based on the total weight of the composite may be about 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt% or 6.5 wt%, and the upper limit may be about 20 wt%, 15 wt% or 10 wt%. The above-mentioned ratio may be within a range that is less than or equal to any upper limit arbitrarily selected from the above-mentioned upper limits and greater than or equal to any lower limit arbitrarily selected from the above-mentioned lower limits.

[0057] In another example, the lower limit of the content of the inorganic gel relative to 100 parts by weight of the volatile material may be about 0.001 parts by weight, 0.005 parts by weight, 0.01 parts by weight, 0.05 parts by weight, 0.1 parts by weight, 0.15 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.3 parts by weight, 0.5 parts by weight, 1 part by weight, 5 parts by weight, 5.5 parts by weight, 6 parts by weight or 6.5 parts by weight, and the upper limit may be about 100 parts by weight, 95 parts by weight, 90 parts by weight, 85 parts by weight, 80 parts by weight, 75 parts by weight, 70 parts by weight, 65 parts by weight, 60 parts by weight, 55 parts by weight, 50 parts by weight, 45 parts by weight, 40 parts by weight, 35 parts by weight, 30 parts by weight, 25 parts by weight, 20 It can be about 1 part by weight, 15 parts by weight, 10 parts by weight, 5 parts by weight, 4 parts by weight, 3 parts by weight, 2 parts by weight, or 1 part by weight. The ratio can be within a range that is less than or equal to an upper limit arbitrarily selected from the upper limits listed above; or within a range that is equal to or greater than an lower limit arbitrarily selected from the lower limits listed above; or within a range that is equal to or greater than an lower limit arbitrarily selected from the lower limits listed above and less than or equal to an upper limit arbitrarily selected from the upper limits listed above.

[0058] The shape of the above-described inorganic gel can be controlled to effectively exhibit the desired effect.

[0059] Hereinafter, a specific explanation will be given by way of example, in which the above-mentioned inorganic gel is silica gel.

[0060] When the above-mentioned inorganic gel is silica gel, the above-mentioned oxide network may be composed of at least one unit represented by the following chemical formulas 1 to 4.

[0061] [Chemical Formula 1]

[0062]

[0063] [Chemical Formula 2]

[0064]

[0065] [Chemical Formula 3]

[0066]

[0067] [Chemical Formula 4]

[0068]

[0069] The units of the above chemical formula are siloxane units, which are called M units (chemical formula 1), D units (chemical formula 2), T units (chemical formula 3), and Q units (chemical formula 4).

[0070] In the structures of chemical formulas 1 to 4, the oxygen atom is connected to a silicon atom of a siloxane unit corresponding to any one of the M, D, T, and Q units to form the network. In the structures of chemical formulas 1 to 4, R is usually hydrogen or a monovalent hydrocarbon group such as an alkyl group.

[0071] The structure of the silica gel network is determined by which of the above units it contains. Among the above units, the M unit exists at the end of the chain of the network, and the D unit contributes to the formation of a linear chain structure. The T and Q units contribute to the formation of a three-dimensional structure such as a branched network or a so-called cage structure. In general, the D unit contributes to the cushioning and elasticity of the network, and the more T and Q units there are, the stronger the network becomes, and the more MO2 (M is an element such as silica), which acts as an insulator or heat-insulating material, also increases as the T and Q units increase. In addition, the increase in T and Q units forms pores within the network, and these pores can play a role in retaining volatile substances, etc., and increasing the heat-insulating and heat-insulating properties.

[0072] Additionally, since the OR moiety of the network contributes to interaction with water through hydrogen bonding, etc., its amount can contribute to the water-holding capacity of the network.

[0073] Meanwhile, in the above structure, the Q unit may exist in the silica gel in any one of the following chemical formulas 5 to 8.

[0074] [Chemical Formula 5]

[0075]

[0076] [Chemical Formula 6]

[0077]

[0078] [Chemical Formula 7]

[0079]

[0080] [Chemical Formula 8]

[0081]

[0082] In the structures of chemical formulas 5 to 8, Si present at the terminal is a silicon atom of a siloxane unit corresponding to any one of the M, D, T, and Q units, and R at the terminal is usually a monovalent hydrocarbon group such as hydrogen or an alkyl group.

[0083] The structures of chemical formulas 5 to 8 all broadly correspond to the Q unit, and are distinguished depending on whether a silicon atom or R is present at the terminal.

[0084] Among the units of the structure of chemical formulas 5 to 8, the more Si there is at the terminal, the denser, stronger, and more uniform the pores are formed, contributing to the formation of a network with excellent insulation and heat-insulating properties. Among the units of the structure of chemical formulas 5 to 8, the more R there is at the terminal, the higher the degree of interaction with other components such as water, contributing to the formation of larger or open pores.

[0085] Therefore, the desired silica gel can be formed by controlling which unit among the siloxane units of the chemical formulas 1 to 8 that constitute the silica gel exists in which ratio.

[0086] The above content 29 This can be confirmed through Si NMR spectrum. 29 The analytical method for obtaining the Si NMR spectrum is described in “Test Example 1” of this specification.

[0087] For example, the above silica gel is 29 The above is the integral of the entire peak of the Si-NMR spectrum compared to W. 29 It can have a structure in which the ratio Q / W of the integral Q in the region of -127 ppm to -66 ppm of the Si-NMR spectrum is within a predetermined range.

[0088] For example, the lower limit of the ratio Q / W may be about 0.7, 0.75, 0.8, 0.85, 0.9, or 0.95, and the upper limit may be about 1. The ratio Q / W may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above; or within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0089] The above integral Q corresponds to the ratio of the units of the chemical formulae 4 to 8 in the silica gel, and the integral W corresponds to the ratio of all siloxane units contained in the silica gel. Therefore, a high Q / W represents that the ratio of Q units among the siloxane units forming the silica gel is high. When the Q / W is within the above range, a silica gel capable of performing the desired function can be formed.

[0090] In addition, the silica gel 29 The percentage of the integral Q of the peak in the region of -94 ppm to -66 ppm compared to the integral Q of the peak in the region of -127 ppm to -66 ppm of the Si-NMR spectrum, Q1+Q2, which is 100×(Q1+Q2) / Q, may be within a predetermined range.

[0091] For example, the lower limit of the above percentage 100×(Q1+Q2) / Q may be about 20%, 25%, 30%, 35%, 40%, 45%, 50%, or 55%, and the upper limit may be about 80%, 75%, 70%, 65%, 60%, 55%, 50%, or 45%. The above percentage may be within a range that is equal to or greater than any lower limit arbitrarily selected from the above-listed lower limits and equal to or less than any upper limit arbitrarily selected from the above-listed upper limits.

[0092] The above integral Q represents the proportion of the total Q units within the silica gel network, and the integral Q1+Q2 represents the proportion of the units of the above chemical formulae 5 and 6 within the silica gel network. Therefore, a silica gel network exhibiting a percentage within the above range can exhibit a balance of appropriate affinity for volatile substances such as water and buffering properties, insulation properties, heat-insulating properties, and dimensional stability.

[0093] In one example, the silica gel 29 The percentage of the integral Q of the peak in the region of -127 ppm to -66 ppm of the Si-NMR spectrum compared to the integral Q of the peak in the region of -127 ppm to -94 ppm, 100×(Q3+Q4) / Q, may be within a predetermined range.

[0094] For example, the lower limit of the above percentage 100×(Q3+Q4) / Q may be about 25%, 30%, 35%, or 40%, and the upper limit may be about 80%, 75%, 70%, 65%, 60%, 55%, 50%, or 45%. The above percentage may be within a range that is equal to or greater than any lower limit arbitrarily selected from the above-listed lower limits and equal to or less than any upper limit arbitrarily selected from the above-listed upper limits.

[0095] The above integral Q represents the proportion of the total Q units within the silica gel network, and the integral Q3+Q4 represents the proportion of the units of the above chemical formulae 7 and 8 within the silica gel network. Therefore, a silica gel network exhibiting a percentage within the above range includes pores formed with a more uniform size, and can exhibit a balance of strength, dimensional stability, thermal insulation, heat rejection, and appropriate affinity and buffering for volatile substances such as water.

[0096] In addition, the silica gel 29 The ratio Q1 / Q2 of the integral Q1 in the -83 ppm to -66 ppm region of the Si-NMR spectrum to the integral Q2 in the -94 ppm to -83 ppm region can be within a predetermined range.

[0097] For example, the lower limit of the ratio Q1 / Q2 may be about 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, or 0.5, and the upper limit may be about 0.9, 0.85, 0.8, 0.75, 0.7, 0.65, 0.6, 0.55, or 0.5. The ratio Q1 / Q2 may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0098] The above integral Q1 represents the ratio of the unit of the above chemical formula 5 within the silica gel network, and the integral Q2 represents the ratio of the unit of the above chemical formula 6 within the silica gel network. Therefore, a silica gel network exhibiting a ratio within the above range can exhibit a balance of appropriate affinity for a volatile substance such as water and thermal insulation, heat-insulating properties, and dimensional stability.

[0099] Silica gel 29The ratio Q4 / Q3 of the integral Q4 in the region of -127 ppm to -105 ppm of the Si-NMR spectrum to the integral Q3 in the region of -105 ppm to -94 ppm may be within a predetermined range.

[0100] For example, the lower limit of the ratio Q4 / Q3 may be about 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7 or 0.75, and the upper limit may be about 0.9, 0.85, 0.8, 0.75, 0.7, 0.65 or 0.6. The ratio Q4 / Q3 may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0101] The above integral Q3 represents the ratio of the unit of the above chemical formula 7 within the silica gel network, and the integral Q4 represents the ratio of the unit of the above chemical formula 8 within the silica gel network. Therefore, a silica gel network exhibiting a ratio within the above range can exhibit a balance of appropriate affinity for volatile substances such as water and thermal insulation, heat-insulating properties, and dimensional stability.

[0102] In addition, the silica gel 29 The ratio Q1 / B of the integral Q1 in the region of -83 ppm to -66 ppm of the Si-NMR spectrum to the integral B in the region of -127 ppm to -83 ppm can be adjusted. For example, the lower limit of the ratio can be about 0.5, 0.1, 0.15 or 0.2, and the upper limit can be about 0.6, 0.55, 0.5, 0.45, 0.4, 0.35, 0.3 or 0.25. The ratio can be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and is equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0103] The above integral Q1 represents the ratio of the units of the above chemical formula 5 within the silica gel network, and the integral B represents the ratio of the Q units excluding the units of the above chemical formula 5. Therefore, a silica gel network exhibiting a ratio within the above range can exhibit a balance of appropriate affinity for volatile substances such as water and thermal insulation, heat-insulating properties, and dimensional stability.

[0104] For example, silica gel 29 The ratio Q4 / R of the integral Q4 in the region of -127 ppm to -105 ppm of the Si-NMR spectrum to the integral R in the region of -105 ppm to -66 ppm may be within a predetermined range. For example, the lower limit of the ratio may be about 0.05, 0.1, 0.15, 0.2, 0.25 or 0.3, and the upper limit may be about 0.6, 0.55, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25 or 0.2. The ratio may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and is equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0105] The above integral Q4 represents the ratio of the units of the above chemical formula 8 within the silica gel network, and the integral R represents the ratio of the Q units excluding the units of the above chemical formula 8. Therefore, a silica gel network exhibiting a ratio within the above range can exhibit a balance of appropriate affinity for volatile substances such as water and thermal insulation, heat-insulating properties, and dimensional stability.

[0106] The above-described inorganic gel can be formed in the manner described below.

[0107] The composite material may further include a vaporizable substance along with the inorganic gel. The term "vaporizable substance" refers to a substance that vaporizes at a given temperature. Such a vaporizable substance may exist in a liquid state at room temperature (25°C). Such a vaporizable substance may be used to reduce abnormal heat, such as through heat exchange, under abnormal conditions, or to eliminate flames generated by ignition and / or explosion. Such a vaporizable substance may rapidly vaporize under abnormal conditions, thereby increasing the pressure in a confined space, opening the vent area, and allowing the substance to be discharged to the outside through the opened vent area.

[0108] As the above-mentioned volatile substance, any substance that can be vaporized and is non-flammable may be used without any special restrictions. For example, the above-mentioned volatile substance may be a solvent having a freezing point and / or boiling point within a certain range.

[0109] For example, the lower limit of the freezing point of the volatile substance may be about -5°C, -4°C, -3°C, -2°C, -1°C, or 0°C, and the upper limit may be about 10°C, 9°C, 8°C, 7°C, 6°C, 5°C, 4°C, 3°C, or 2°C. The freezing point may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. The freezing point is a freezing point under 1 atm.

[0110] In order for the above-mentioned volatile substance to effectively respond to the above-mentioned heat generation, ignition and / or explosion, it may be advantageous for the above-mentioned volatile substance to be vaporized at least by the heat generated by the above-mentioned heat generation, ignition and explosion, and for this purpose, the boiling point of the above-mentioned volatile substance may be controlled.

[0111] The lower limit of the boiling point of the above-mentioned volatile substance may be about 80°C, 85°C, 90°C, or 95°C, and the upper limit may be about 120°C, 115°C, 110°C, or 105°C. The boiling point may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. The boiling point is a boiling point under 1 atm.

[0112] Any volatile substance having a freezing point and / or boiling point within the above range and being non-flammable may be selected and used without any special restrictions. A representative example of such a volatile substance is water, and thus water can be used as the volatile substance. However, the types of applicable volatile substances are not limited to the above.

[0113] The lower limit of the proportion of the volatile material in the composite may be, for example, about 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt% or 80 wt%, and the upper limit may be about 95 wt%, 90 wt%, 85 wt%, 80 wt%, 75 wt%, 70 wt%, 65 wt%, 60 wt%, 55 wt%, 50 wt%, 45 wt% or 40 wt%. The proportion is within a range that is greater than or equal to any lower limit arbitrarily selected from among the lower limits listed above; Or, it may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0114] The above ratio is a ratio confirmed when the total weight of the composite material is 100 wt%, and the method for obtaining this ratio is described in the Examples section.

[0115] The above composite material can exhibit a predetermined heat absorption amount.

[0116] The lower limit of the heat absorption of the above composite material may be about 600, 700, 800, 900, 1,000, 1,100, 1,200, 1,300, 1,400, 1,500, 1,600 or 1,700, and the upper limit may be about 2,500, 2,400, 2,300, 2,200, 2,100, 2,000, 1,900, 1,800, 1,700, 1,600, 1,500, 1,400, 1,300, 1,200, 1,100 or 1,000. The heat absorption is within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above; Or, it may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0117] The unit of the above heat absorption is J / g. This heat absorption can be adjusted by adjusting various components within the composite, and can generally be controlled by the amount of the volatile material. Methods for measuring the heat absorption are described in the examples of this specification.

[0118] The composite may include an ionic compound as an additional component. The term ionic compound refers to a compound that can form ions when dissolved in a volatile substance such as water, such as a metal salt, an acid, or a base.

[0119] These ionic substances may be added as a freezing point regulator to control the freezing point of a volatile substance in the composite, or as a catalyst for forming the inorganic gel.

[0120] The term "freezing point regulator" refers to a compound capable of adjusting the freezing point of the composite and / or the volatile substance. By applying such a freezing point regulator in an appropriate ratio, the rate at which the volatile substance within the composite is released from an ideal state can be controlled. Furthermore, the addition of a freezing point regulator allows the composite to exhibit its designed performance regardless of the temperature of the environment in which it is applied.

[0121] As a freezing point regulator, a material having a certain level of solubility in the above-mentioned volatile substance or water can be used. To select a freezing point regulator with an appropriate solubility, the degree of freedom in the amount of the freezing point regulator added is increased, and thus, an amount that can secure the desired freezing point without impairing the fire extinguishing function and improving it can be selected.

[0122] The lower limit of the solubility of the above freezing point regulator in water 100 at 0℃ may be about 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210 or 215, and the upper limit may be about 1000, 900, 800, 700, 600, 500, It can be 400, 300, 250, 245, 240, 235, 230, 225, 220, 215, 210, 205, 200, 195, 190, 185, 180, 175, 170, 165, 160, 155, 150, 145, 140, 135, 130, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, or 30. The solubility may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. The solubility is the weight of the freezing point regulator that can be dissolved at most in 100 g of water at 0°C, and the unit of the solubility is g. The solubility may be defined as the amount of a sample that can be dissolved at most in 100 g of water at 0°C according to ASTM E1148-02.

[0123] The lower limit of solubility of the above freezing point regulator in 100 g of water at 25°C is 70, 75, 80, 85, 90, 95, 100, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 225, 230, 235, 240, 255, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, It can be around 310, 315 or 320, and its upper limit is 1000, 900, 800, 700, 600, 500, 400, 350, 345, 340, 335, 330, 325, 320, 315, 310, 305, 300, 295, 290, 280, 275, 270, 265, 260, 255, 250, 245, 240, 235, 230, 225, 220, 215, 210, 205, 200, 195, 190, 185, 180, 175, 170, 165, It can be about 160, 155, 150, 145, 140, 135, 130, 125, 120, 115, 110, 105 or 100. The solubility can be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. The solubility is the weight of the freezing point regulator that can be dissolved to the maximum extent in 100 g of water at 25°C, and the unit of the solubility is g. The solubility can be defined as the amount of a sample that can be dissolved to the maximum extent in 100 g of water at 25°C according to ASTM E1148-02.

[0124] As ionic compounds that can be applied as freezing point regulators, one or more selected from the group consisting of ammonium salts, formates, acetates, carbonates, and sulfates can be exemplified. Specifically, for example, at least one of substances composed of sodium acetate (CH3COONa), sodium formate (HCOONa), potassium acetate (CH3COOK), potassium formate (HCOOK), calcium formate ((HCOO)2Ca), magnesium formate ((HCOO)2Mg), potassium carbonate (K2CO3), and ammonium sulfate ((NH4)2SO4) can be used as the freezing point regulator.

[0125] The amount of freezing point regulator added can be adjusted in consideration of the desired freezing point. In one example, the freezing point regulator is △T of the following equation 1. f It can exist in a quantity that is within a certain range.

[0126] [Formula 1]

[0127] △T f = K f × M × I

[0128] K in Equation 1 f is the freezing point depression constant of the volatile substance, M is the molal concentration of the freezing point regulator (ionic compound) with respect to the volatile substance, and I is the number of moles of ions generated when 1 mole of the freezing point regulator (ionic compound) is completely dissociated.

[0129] K in Equation 1 f is the freezing point depression constant of a volatile substance, and its unit is K / m or ℃ / m. For example, if the volatile substance is water, the above K f is about 1.86.

[0130] M in Equation 1 is the molal concentration of the freezing point regulator, which is the molal concentration relative to the volatile substance. Therefore, M is the number of moles of the freezing point regulator (ionic compound) present per 1 kg of the volatile substance in the composite.

[0131] I in Equation 1 is the number of ions (moles) formed by 1 mole of the freezing point regulator when the freezing point regulator is dissociated, and in this case, dissociation means a state in which the freezing point regulator is completely dissociated.

[0132] △T in Equation 1 f The lower limit of may be, for example, 1, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18, and the upper limit may be, for example, 50, 45, 40, 35, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17 or 16, 15, 14, 13, 12 or 11. The above △T f It may be within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. △T in Equation 1 f The unit is ℃. Within the above range, the composite material can exhibit desired hardness characteristics, etc., and can exhibit an appropriate vaporization speed when necessary.

[0133] For example, the lower limit of the weight part of the freezing point regulator relative to 100 parts by weight of the volatile material may be about 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight or 55 parts by weight, and the upper limit may be about 200 parts by weight, 150 parts by weight, 100 parts by weight, 95 parts by weight, 90 parts by weight, 85 parts by weight, 80 parts by weight, 75 parts by weight, 70 parts by weight, 65 parts by weight, 60 parts by weight, 55 parts by weight, 50 parts by weight, 45 parts by weight, 40 parts by weight, 35 parts by weight or 30 parts by weight. The ratio is within a range that is equal to or less than any one upper limit arbitrarily selected from the upper limits listed above; Or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0134] The above composite may further include inorganic fibers. These inorganic fibers may provide the composite with the aforementioned cushioning properties and, in some cases, may serve to support some or all of the components, such as the volatile substances, described above. Furthermore, the inorganic fibers may influence the polymerization efficiency during the formation of the inorganic gel, thereby contributing to the formation of the desired inorganic gel.

[0135] As inorganic fibers, for example, inorganic fibers commonly used in the formation of insulating materials can be used, such as so-called glass fibers, basalt fibers, and / or ceramic fibers. Such inorganic fibers can exist in the form of, for example, paper, woven fabrics, or non-woven fabrics. The category of woven fabrics or non-woven fabrics may also include objects referred to as wool or blankets.

[0136] When the above-mentioned inorganic fiber is included in the form of a woven fabric or a non-woven fabric, the thickness of the woven fabric or the non-woven fabric may be selected within a range capable of exhibiting the above-described characteristics. For example, the lower limit of the thickness may be about 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, or 3, and the upper limit may be about 100, 50, 30, 10, 8, 6, or 4. The thickness may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above. The unit of the thickness is mm.

[0137] The above-mentioned inorganic fibers may be present in the composite material in an appropriate ratio. For example, the lower limit of the weight ratio of the inorganic fiber to 100 parts by weight of the volatile material may be about 0.5 parts by weight, 1 part by weight, 5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, 8.5 parts by weight, 10 parts by weight, 20 parts by weight, 30 parts by weight, 40 parts by weight, 50 parts by weight, 60 parts by weight, 70 parts by weight or 75 parts by weight, and the upper limit may be about 200 parts by weight, 180 parts by weight, 160 parts by weight, 140 parts by weight, 120 parts by weight, 100 parts by weight, 95 parts by weight, 90 parts by weight, 85 parts by weight, 80 parts by weight, 75 parts by weight, 70 parts by weight, 65 parts by weight, 60 parts by weight, 55 parts by weight, 50 parts by weight, 45 parts by weight, 40 parts by weight, 35 The ratio may be about 30 parts by weight, 25 parts by weight, 20 parts by weight, 15 parts by weight, 10 parts by weight, 8 parts by weight, 6 parts by weight, 4 parts by weight, or 3 parts by weight. The ratio may be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above; or within a range that is greater than or equal to any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0138] In another example, the lower limit of the weight ratio of the inorganic fiber to 100 parts by weight of the inorganic gel may be about 50 parts by weight, 100 parts by weight, 150 parts by weight, 200 parts by weight, 250 parts by weight, 300 parts by weight, 500 parts by weight, 700 parts by weight, or 900 parts by weight, and the upper limit may be about 2,000 parts by weight, 1,500 parts by weight, 1,000 parts by weight, 800 parts by weight, 600 parts by weight, 500 parts by weight, 400 parts by weight, or 300 parts by weight. The ratio may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and is equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0139] When the above-described inorganic fibers and inorganic gel exist simultaneously, the inorganic gel may be attached to the inorganic fibers, or the inorganic gel and the inorganic fibers may exist in a state of being entangled with each other. For example, as described below, the above-described structure can be realized by performing the gelation process in the presence of the inorganic fibers, thereby allowing the composite to exhibit desired properties and perform the desired function more effectively.

[0140] The above composite material includes the above components and may include additional optional components if necessary.

[0141] The above composite material can be manufactured by mixing the aforementioned components. For example, the method for manufacturing the above composite material can include a method for manufacturing the above-described inorganic gel, such as silica gel.

[0142] The present specification discloses a method for producing the above composite material or silica gel.

[0143] For example, the method may include a step of polymerizing a precursor solution comprising a precursor of an inorganic gel (e.g., silica gel), a catalyst, and the volatile material to form the silica gel described above.

[0144] Polymerization, as described above, is a process in which a relatively low molecular weight substance, such as a monomer or oligomer, forms a chain or network to form a high molecular weight component, and the monomer or oligomer may be the precursor. Furthermore, there are no specific limitations on the polymerization method, and it may be determined based on the type of precursor, an example of which is the so-called sol-gel process.

[0145] As the precursor, for example, a metal alkoxide may be used. Specifically, the alkoxide may be one or more alkoxides selected from the group consisting of silicon, titanium, zirconium, niobium, tantalum, molybdenum, and tungsten. At this time, the lower limit of the number of carbon atoms present in the alkoxide may be about 4, 6, 8, or 10, and the upper limit may be about 20, 18, 16, 14, 12, 10, or 8. The number of carbon atoms may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above, and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0146] The above alkoxide may be applied to the above manufacturing step in a hydrated state. Hydration of the alkoxide may be performed, for example, through a step of mixing the alkoxide, a solvent, an alcohol, and an acid catalyst.

[0147] During this process, the above components may be mixed simultaneously or in two or more stages. For example, some components may be mixed first, followed by the remaining components. Furthermore, any one of the components listed above may be mixed separately in two or more stages. For example, among the above components, an alkoxide, a solvent, and an alcohol may be mixed, and an acid catalyst may be additionally mixed.

[0148] As the alcohol, a monohydric alcohol can be used, and for example, a monohydric alcohol having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms can be used.

[0149] The lower limit of the blending amount of the alcohol may be about 50 parts by weight, 70 parts by weight, 90 parts by weight, or 95 parts by weight relative to 100 parts by weight of the alkoxide, and the upper limit may be about 150 parts by weight, 130 parts by weight, 110 parts by weight, or 105 parts by weight relative to 100 parts by weight of the alkoxide. The blending amount may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above, and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0150] There is no particular limitation on the type of solvent applied for hydration of the alkoxide, and a solvent generally applied in the sol-gel process can be used. For example, a solvent applied for the progress of step (1) can be used. In this case, the lower limit of the amount of the solvent may be about 1 mol, 2 mol, 3 mol, or 4 mol per 1 mol of the alkoxide, and the upper limit may be about 10 mol, 9 mol, 8 mol, 7 mol, 6 mol, 5 mol, or 4 mol per 1 mol of the alkoxide. The amount of the solvent may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above, and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0151] There is no particular limitation on the type of catalyst applied for the above hydration. As a catalyst, an acid catalyst or a base catalyst applied in a general sol-gel process can be used. Examples of such acid catalysts include one or a mixture of two or more selected from hydrochloric acid, sulfuric acid, fluorosulfuric acid, nitric acid, phosphoric acid, acetic acid, hexafluorophosphoric acid, p-toluenesulfonic acid, and trifluoromethanesulfonic acid, and examples of base catalysts include, but are not limited to, alkaline catalysts such as sodium hydroxide, ammonium hydroxide, or ammonium chloride.

[0152] The amount of the catalyst in the hydration step can be adjusted in consideration of the pH of the mixture. For example, the catalyst can be mixed so that the pH of the mixture is within a predetermined range. The lower limit of the pH can be about 0, 0.5, 1, 1.5, 2, or 2.5, and the upper limit can be about 7, 6.5, 6, 5.5, 5, 4.5, 4, 3.5, or 3. The pH can be within a range that is less than or equal to any upper limit arbitrarily selected from the upper limits listed above; or within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and less than or equal to any upper limit arbitrarily selected from the upper limits listed above.

[0153] There is no limitation on the type of catalyst as long as the above pH can be satisfied, but it is usually advantageous to use an acid catalyst to satisfy the above pH.

[0154] The above precursor may also be applied to so-called water glass (sodium silicate).

[0155] In order to form an inorganic gel of the desired shape, the content of the precursor in the precursor solution can be controlled in the above step.

[0156] For example, the lower limit of the content of the precursor in the precursor solution may be about 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 or 65, and the upper limit may be about 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10 or 7. The ratio may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0157] The above content is a value obtained by taking the sum of the weights of the precursor, catalyst, and vaporizable material in the precursor solution or the total weight of the precursor solution as 100% by weight, and its unit is weight%. By performing polymerization under the above ratio to form an inorganic gel, an inorganic gel of the desired shape can be formed.

[0158] In the above, the lower limit of the content of the vaporizable material relative to 100 parts by weight of the precursor may be about 20 parts by weight, 40 parts by weight, 100 parts by weight, 150 parts by weight, 300 parts by weight, 350 parts by weight, 500 parts by weight, 1,000 parts by weight, 1,100 parts by weight, 1,200 parts by weight, or 1,300 parts by weight, and the upper limit may be about 2,500 parts by weight, 2,000 parts by weight, 1,500 parts by weight, 1,000 parts by weight, 500 parts by weight, 250 parts by weight, 100 parts by weight, 80 parts by weight, 60 parts by weight, or 50 parts by weight. The ratio may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above. By performing polymerization under the above ratio to form an inorganic gel, an inorganic gel of the desired shape can be formed.

[0159] The molal concentration of the catalyst with respect to the vaporizable substance in the above precursor solution can be controlled. For example, the lower limit of the molal concentration can be about 0.005, 0.01, 0.04, 0.05, 0.1, 0.2, 0.3, 0.5, or 1, and the upper limit can be about 10, 8, 6, 4, 2, 1.5, 1, 0.8, 0.6, 0.4, 0.1, or 0.05. The ratio can be within a range that is equal to or greater than any lower limit arbitrarily selected from the above-listed lower limits and equal to or less than any upper limit arbitrarily selected from the above-listed upper limits. The molal concentration is the number of moles of the catalyst present per 1 kg of the vaporizable substance.

[0160] There is no particular limitation on the type of catalyst added in the above process, and for example, an appropriate acid catalyst and / or base catalyst known as a catalyst of the sol gel process, such as the metal alkoxide or water glass, can be applied.

[0161] The polymerization can be performed while the pH of the above-mentioned precursor solution is adjusted to an appropriate level. For example, the lower limit of the pH in the above process can be about 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, or 7, and the upper limit can be about 14, 13, 12, 11, 10, 9, 8, or 7. The pH can be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above, and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0162] The desired inorganic gel can be obtained by polymerizing the above-mentioned precursor solution, and the polymerization temperature can be adjusted during this process.

[0163] For example, the lower limit of the polymerization temperature may be about 10°C, 15°C, 20°C, or 25°C, and the upper limit may be about 40°C, 35°C, 30°C, or 25°C. The temperature may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0164] To obtain the desired inorganic gel, the polymerization may be carried out in multiple stages.

[0165] For example, the polymerization step may include a first step of polymerizing the precursor solution to obtain a prepolymer, and a second step of polymerizing the prepolymer to obtain silica gel.

[0166] In the above, the prepolymer may be, for example, an inorganic sol that has undergone a solization process, for example, a silica sol.

[0167] The above primary polymerization can be performed at the above-mentioned polymerization temperature, and for example, can be performed while stirring the precursor solution at an appropriate speed at the above-mentioned polymerization temperature.

[0168] For example, the lower limit of the stirring speed may be about 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm, or 500 rpm, and the upper limit may be about 2,000 rpm, 1,500 rpm, 1,000 rpm, 800 rpm, 600 rpm, 400 rpm, or 300 rpm. The temperature may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0169] The lower limit of the time for performing the above primary polymerization (e.g., the above sol-ization reaction) may be about 1 second, 5 seconds, 10 seconds, 30 seconds, 1 minute, 5 minutes, 10 minutes, or 15 minutes, and the upper limit may be about 60 minutes, 55 minutes, 50 minutes, 45 minutes, 40 minutes, 35 minutes, 30 minutes, 25 minutes, 20 minutes, 15 minutes, 10 minutes, 8 minutes, 6 minutes, 4 minutes, 2 minutes, 1 minute, or 30 seconds. The time may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0170] The prepolymer (e.g., inorganic sol or silica sol) formed by the above-mentioned first polymerization can be further polymerized secondaryally to form an inorganic gel. To form the desired inorganic gel, the secondary polymerization can be performed in the presence of inorganic fibers (the inorganic fibers described above). Performing the polymerization in the presence of such inorganic fibers can control the reaction efficiency between the monomers or prepolymers, thereby effectively forming the desired inorganic gel.

[0171] In this process, the content of the inorganic fiber applied can be adjusted. For example, the lower limit of the content of the inorganic fiber relative to 100 parts by weight of the precursor of the inorganic gel or the prepolymer may be about 10 parts by weight, 20 parts by weight, 25 parts by weight, 50 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight, 100 parts by weight, 150 parts by weight, 200 parts by weight, or 250 parts by weight, and the upper limit may be about 500 parts by weight, 400 parts by weight, 300 parts by weight, 200 parts by weight, 100 parts by weight, 80 parts by weight, 60 parts by weight, 40 parts by weight, or 30 parts by weight. The above ratio may be within a range that is equal to or greater than any lower limit arbitrarily selected from the lower limits listed above and equal to or less than any upper limit arbitrarily selected from the upper limits listed above.

[0172] This secondary polymerization can be performed within the polymerization temperature range described above. For example, the prepolymer can be mixed with the inorganic fibers, and the polymerization can be performed while maintaining the mixture at the above temperature. There are no specific restrictions on the polymerization time during this process, and it can be adjusted within a range that allows the formation of the desired gel.

[0173] Through the above process, an inorganic gel is formed, and other necessary components, such as the aforementioned freezing point regulator, opacifier (e.g., TiO2, Fe2O3, and / or SiC, etc.), and / or flame retardant (MC, Ultracarb, Al(OH)3, Mg(OH)2, etc.), can be mixed to manufacture the composite. The mixing of these additional components can be performed before or after the process of manufacturing the inorganic gel, or during the process of manufacturing the inorganic gel.

[0174] After manufacturing the composite in this manner, the composite can be placed within a case to form a heat absorbing device. This process can be performed within the case after the entire composite has been manufactured, or it can be performed within the case during the entire composite manufacturing process or as part of the entire process. For example, the heat absorbing device and the composite can be manufactured simultaneously by pre-injecting inorganic fibers within the case, injecting a prepolymer, and then performing additional polymerization.

[0175] The present specification also discloses an electronic equipment or device to which the above heat absorbing device is applied.

[0176] The type of electronic equipment or device is not particularly limited. For example, the composite material or heat-absorbing device may be applied to equipment or devices that are likely to experience abnormal conditions and require control of such conditions.

[0177] Examples of the above equipment or devices include batteries. In particular, in battery modules comprised of multiple battery cells, it is crucial to prevent abnormal heat generation, ignition, and / or explosion from occurring in one battery cell from spreading to adjacent battery cells.

[0178] The present specification discloses a battery module including the above heat absorbing device.

[0179] Such a battery module may basically include a plurality of battery cells; and the heat absorbing device disposed between the battery cells.

[0180] As long as the above-mentioned heat absorbing device is applied, the specific configuration of the battery module, for example, the type of the battery cell, etc., is not particularly limited, and any known material may be applied. For example, any known pouch-shaped, square-shaped, or cylindrical battery cell may be applied as the battery cell.

[0181] The method for manufacturing the above battery module is not particularly limited, and for example, a method may be used in which a heat absorbing device in the form of a battery cell is manufactured as described above, and then the heat absorbing device is positioned at a required location during the manufacturing process of the battery module.

[0182] The present specification discloses a composite material and a heat absorbing device that can be applied to a product or device that is in an abnormal state or has the potential to experience such an abnormal state, and can effectively respond to heat, ignition, and explosion during such an abnormal state. For example, the composite material and heat absorbing device can be applied to an article comprising multiple products or devices, and can respond to abnormal heat generation, explosion, and ignition occurring in one of the devices or products, and prevent or minimize the spread of such heat generation, explosion, and ignition to other adjacent devices or products. The composite material and heat absorbing device also exhibit excellent handling and storage stability. The present specification can also provide uses for the composite material and heat absorbing device.

[0183] Figure 1 is an exemplary cross-sectional view of a battery module to which a heat absorbing device is applied.

[0184] Figures 2 and 3 are exemplary drawings for explaining the operating principle of the heat absorbing device.

[0185] Figure 4 is an exemplary drawing of an outer shell for packaging a composite material.

[0186] Figure 5 is the silica gel of Example 1. 29 This is a Si-NMR spectrum.

[0187] Figure 6 is the silica gel of Example 2. 29 This is a Si-NMR spectrum.

[0188] Figure 7 is the silica gel of Example 3. 29 This is a Si-NMR spectrum.

[0189] Figure 8 is the silica gel of Example 4. 29 This is a Si-NMR spectrum.

[0190] The composite material and the like are specifically described with reference to the following examples, but the scope of the composite material and the like is not limited by the following examples.

[0191]

[0192] Example 1.

[0193] Distilled water (D), an aqueous acetic acid solution (acetic acid concentration: 98 wt%) (Y), and liquid sodium silicate (S) were mixed. As the liquid sodium silicate, No. 3 (KS) (No. 3 KS) (Na2O content: about 9 to 10 wt%, SiO2 content: about 28 to 30 wt%, sodium silicate molar ratio (= 1.032 × (SiO2 weight) / (Na2O weight)): about 3.1 to 3.3) of Youngil Chemical Co., Ltd. was used. The mixing was performed at a weight ratio (D:Y:S) of about 62.5:1:4.6, and the molal concentration of the acetic acid in the mixture based on the distilled water was about 0.26. The pH of the mixture was at the level of 5 to 7.

[0194] The above mixture was stirred for about 10 seconds at a temperature of 25°C and a stirring speed of 250 rpm to form a silica sol, and then the silica sol was applied to ceramic paper (HITEMS, HT Ceramic fiber paper, 190 kg / m 3 )(M) and further gelled in that state to produce a composite. The gelling was induced within 15 minutes after impregnation of the silica sol. During the impregnation, the weight ratio (S:M) of the liquid sodium silicate (S) added during the preparation of the mixture and the ceramic paper (M) was approximately 4.6:13.2.

[0195] In order to manufacture the heat absorbing device, two outer shells (121, 122) as shown in Fig. 4 were prepared. Each of the outer shells is made of Al material and has a WVTR (Water Vapor Transmission Rate) of approximately 0 g / m 2·It was about day. The above WVTR was evaluated according to the standard of ASTM F1249 under the conditions of 38℃ and 100% relative humidity. The composite material was placed in the concave portion (I) of the lower outer shell (122), and after covering it with the upper outer shell (121), the connection portion (S) of the upper outer shell (121) and the lower outer shell (122) was fused at a temperature of about 200℃ to manufacture a heat absorbing device.

[0196]

[0197] Example 2.

[0198] A mixture was prepared by mixing primary distilled water (D), an aqueous acetic acid solution (acetic acid concentration: 98 wt%) (Y), and liquid sodium silicate (S) in a weight ratio (D:Y:S) of 13.9:1:4.3. The same liquid sodium silicate as in Example 1 was used. The molal concentration of the acetic acid in the mixture was about 1.17, and the pH of the mixture was about 6 to 8. Using the mixture, a silica sol, a composite, and a heat absorbing device were prepared in the same manner as in Example 1. The weight ratio (S:M) of the liquid sodium silicate (S) and the ceramic paper (same as that applied in Example 1) (M) applied in the preparation of the mixture during the preparation of the composite was about 4.3:3.7.

[0199]

[0200] Example 3.

[0201] A mixture was prepared by mixing primary distilled water (D), NaOH aqueous solution (NaOH concentration 40 wt%) (Y), and liquid sodium silicate (S). The liquid sodium silicate was the same as that used in Example 1, and the weight ratio (D:Y:S) at the time of mixing was approximately 227.7:1:57.6, the molal concentration of the NaOH was approximately 0.04, and the pH was approximately 5 to 7. Using the mixture, a silica sol, a composite, and a heat absorbing device were prepared in the same manner as in Example 1. The weight ratio (S:M) of the liquid sodium silicate (S) and the ceramic paper (same as that used in Example 1) (M) applied at the time of preparing the mixture at the time of preparing the composite was approximately 57.6:56.0.

[0202]

[0203] Example 4.

[0204] A mixture was prepared by mixing primary distilled water (D), NaOH aqueous solution (NaOH concentration 40 wt%) (Y), and liquid sodium silicate (S). The liquid sodium silicate was the same as that used in Example 1, and the weight ratio (D:Y:S) at the time of mixing was approximately 58.7:1:119.3, the molal concentration of the NaOH was approximately 0.17, and the pH was approximately 5 to 7. Using the mixture, a silica sol, a composite, and a heat absorbing device were prepared in the same manner as in Example 1. The weight ratio (S:M) of the liquid sodium silicate (S) and the ceramic paper (same as that used in Example 1) (M) applied at the time of preparing the mixture at the time of preparing the composite was approximately 119.3:33.2.

[0205]

[0206] Comparative Example 1.

[0207] A heat absorbing device was manufactured in the same manner as in Example 1 using a PU (Polyurethane) pad (LG Chemical, 0.2 g / cc) as a composite material.

[0208]

[0209] Comparative Example 2.

[0210] A heat absorbing device was manufactured in the same manner as in Example 1, using only the ceramic paper used in the example as a composite material.

[0211]

[0212] The ratios of the main components and the heat absorption of the composites of the examples and comparative examples are summarized and described in Table 1 below. In Table 1 below, in the examples, the water content is the weight % based on 100% of the total weight of the composite, and the contents of SiO2 (silica gel) and the base material are the weight ratios based on 100 parts by weight of the water. In addition, the base material refers to the ceramic paper used in the examples and comparative example 2, and refers to the PU pad in the cases of comparative example 1 and comparative example 2.

[0213] Composite material content (wt%)SiO2 content (parts by weight)Parent material content (parts by weight)Heat absorption (J / g)Example 183.41.9181756.4Example 279.36.8181042.8Example 383.41.9181298.1Example 479.36.818980.5Comparative example 100100-Comparative example 200100-

[0214] In Table 1, the water content was obtained according to Equation 1 below.

[0215] [Formula 1]

[0216] Water content = {(ab) / a} × 100

[0217] In Equation 1, a is the weight of the manufactured composite before drying, and b is the weight of the composite having the weight a after drying for 24 hours in a convection oven at 150°C.

[0218] In Table 1, the contents of SiO2 and the parent material were obtained through the amount of liquid sodium silicate applied during composite manufacturing, the amount of the parent material (ceramic paper), and the amount of water obtained above.

[0219] The heat absorption in Table 1 is a value obtained by integrating the interval between the left on-set point and the right on-set point of the endothermic peak obtained by thermogravimetric differential calorimetry. The thermogravimetric differential calorimetry analysis was performed by loading approximately 5±1 mg of a sample (composite) into the SDT open pan of an analysis device (SDT 650), injecting air into the device at a rate of 0.5 mL / min, and increasing the temperature from 50°C to 200°C at a heating rate of 10°C / min.

[0220]

[0221] Test Example 1: 29 Si-NMR analysis

[0222] The composite was removed from the heat absorber and placed in a convection oven, dried at 95°C for 20 hours to remove moisture, and ground finely with a mortar and pestle to prepare a sample. The NMR analysis instrument used was a Bruker AVANCE III HD 400MHz NMR / 4mm M4_WVT probe, and the sample was placed in a 4 mm ZrO2 MAS rotor and measurements were performed under the following measurement conditions.

[0223] <Measurement conditions>

[0224] - Pulse sequence: 29 Si one pulse

[0225] - d1 (delay time): 25 sec

[0226] - ns(number of scans): 3072

[0227] - Spinning rate: 10,000Hz

[0228] - Temperature: 398K (room temperature)

[0229]

[0230] 29After Si NMR analysis, the integral value of the peak in the region of -66 ppm to -83 ppm of the spectrum was designated as Q1, the integral value of the peak in the region of -83 ppm to -94 ppm was designated as Q2, the integral value of the peak in the region of -94 ppm to -105 ppm was designated as Q3, and the integral value of the peak in the region of -105 ppm to -127 ppm was designated as Q4.

[0231] The deconvolution conditions for this process are as follows.

[0232] <Deconvolution 조건>

[0233] Software: OriginPro 2022b

[0234] Condition: Multiple peak fit analysis

[0235] Peak function: Gauss

[0236]

[0237] The measurements for each example in Figures 5 to 8 are as follows: 29 This is a Si-NMR spectrum.

[0238] In addition, the values ​​of Q1 to Q4 are summarized and described in Table 2 below.

[0239] In Table 2 below, the Q1 value is the percentage of the integral of the peak in the -66 ppm to -83 ppm region relative to the integral of all peaks in the -127 ppm to -66 ppm region of the NMR spectrum, the Q2 value is the percentage of the integral of the peak in the -83 ppm to -94 ppm region relative to the integral of all peaks in the -127 ppm to -66 ppm region of the NMR spectrum, the Q3 value is the percentage of the integral of the peak in the -94 ppm to -105 ppm region relative to the integral of all peaks in the -127 ppm to -66 ppm region of the NMR spectrum, and the Q4 value is the percentage of the integral of the peak in the -105 to -127 ppm region relative to the integral of all peaks in the -127 ppm to -66 ppm region of the NMR spectrum.

[0240] In addition, in the case of the embodiment, the ratio (Q1+Q2+Q3+Q4) / W of the sum of Q1, Q2, Q3, and Q4 (Q1+Q2+Q3+Q4) to the integral W of the entire peak of the NMR spectrum was at a level within the range of 0.9 to 1.

[0241] Q1Q2Q3Q4Example 116.533.832.217.5Example 214.229.433.323.1Example 317.739.226.816.3Example 417.833.527.820.9Comparative Example 1----Comparative Example 2----

[0242] Test Example 2: Torch Test

[0243] The composite material of the example or comparative example was cut to have a length and width of approximately 10 cm each. A flame was sprayed onto one surface of the composite material using a torch and butane gas, and the temperature of the flame touching the surface was maintained at 1000°C.

[0244] After maintaining the above condition for 1 minute, the temperature of the opposite surface of the composite was measured, and the results are shown in Table 3 below.

[0245] Torch test Front (℃) / Back (℃) Example 1582 / 84 Example 2460 / 83 Example 3540 / 70 Example 4430 / 78 Comparative example 1950 / 494 Comparative example 2950 / 462

[0246] From the results in Table 3, it can be seen that in the cases of Examples 1 to 4, the temperature of the surface directly exposed to the flame is also maintained low, and the heat transfer is effectively blocked, so that the temperature of the opposite surface is also maintained extremely low.

[0247] These results are the result of the combination of the specific network structure of silica gel within the composite and the volatile substance, water.

[0248] That is, the above 29 In the Si NMR results, the integral of the Q1 peak is (RO)3SiO among the Si of the Q structure within the network of silica gel.1 / 2 represents the ratio of Si in the Q structure within the silica gel network, and the integral of the Q2 peak is (RO)2SiO 2 / 2 represents the ratio of Si in the Q structure within the silica gel network, and the integral of the Q3 peak is (RO)SiO 3 / 2 represents the ratio of Si in the Q structure within the network of silica gel, and the integral of the Q4 peak is SiO among the Si in the Q structure within the network of silica gel. 4 / 2 It represents the ratio of Si.

[0249] SiO in this Q structure 4 / 2 and (RO)SiO 3 / 2 Si mainly contributes to the increase in the degree of crosslinking and density of the silica gel network, and additionally contributes to the formation of a silica gel network that is more rigid, dense, and has uniform pores, and can form a relatively large amount of SiO2 that can improve the insulating or heat-insulating properties. Meanwhile, (RO)3SiO 1 / 2 and (RO)2SiO 2 / 2 The Si of silica gel contributes to the polarity of silica gel and the interaction with volatile substances (water) through hydrogen bonding, thereby enabling the silica gel network to stably retain a larger amount of volatile substances (water).

[0250] Accordingly, it can be confirmed that the silica gel in which the ratio of Q1 to Q4 is controlled within the range disclosed in the present specification possesses the above characteristics in an appropriate balance, stably retains water, which is a volatile substance, exhibits structural stability, and maximizes the heat absorption characteristics of water, which is a volatile substance, and the insulation and heat resistance of the silica gel network to exhibit a rapid fire-extinguishing action and a chain reaction fire suppression effect and an insulation effect.

Claims

1. A composite material containing silica gel, The above silica gel 29 A composite material having a percentage of the integral of the peak in the region of -94 ppm to -66 ppm relative to the integral of the peak in the region of -127 ppm to -66 ppm of the Si-NMR spectrum within a range of 20% to 80%.

2. In the first paragraph, the silica gel 29 A composite material having a ratio Q1 / Q2 of the integral Q1 in the region of -83 ppm to -66 ppm of the Si-NMR spectrum to the integral Q2 in the region of -94 ppm to -83 ppm within a range of 0.2 to 0.

9.

3. In the first or second paragraph, the silica gel 29 A composite material having a ratio A / B of the integral B in the -127 ppm to -83 ppm region of Q1 relative to the integral B in the -83 ppm to -66 ppm region of the Si-NMR spectrum within a range of 0.1 to 0.

6.

4. In any one of paragraphs 1 to 3, 29 A composite material having a ratio Q / W of the integral of the entire peak of the Si-NMR spectrum W to the integral of the region from -127 ppm to -66 ppm of 0.7 or more.

5. A composite material further comprising a volatile material according to any one of claims 1 to 4.

6. A composite material in paragraph 5, wherein the volatile material is water.

7. A composite material according to claim 5 or 6, wherein the content of the volatile material is 40 to 90 wt%.

8. A composite material comprising 0.5 to 20 parts by weight of silica gel relative to 100 parts by weight of the volatile material according to any one of claims 5 to 7.

9. A composite material further comprising inorganic fibers according to any one of claims 1 to 8.

10. In paragraph 9, the inorganic fiber is a composite material existing in the form of woven fabric, nonwoven fabric or paper.

11. A composite material according to claim 9 or 10, wherein silica gel is attached to inorganic fibers or the silica gel and inorganic fibers are entangled with each other.

12. A composite material further comprising an ionic compound according to any one of claims 5 to 11.

13. In the 12th paragraph, △T of the following equation 1 f Composite containing an ionic compound so that the molecular weight is in the range of 1 to 50: [Formula 1] △T f = K f ×M×I K in Equation 1 f is the freezing point depression constant of the volatile substance, M is the molal concentration of the ionic compound with respect to the volatile substance, and I is the number of moles of ions produced when 1 mole of the ionic compound is completely dissociated.

14. A composite material according to claim 12 or 13, wherein the ionic compound is at least one selected from the group consisting of ammonium salts, formates, acetates, carbonates, and sulfates.

15. Polymerizing a precursor solution containing a silica gel precursor, catalyst, and volatile material. 29 A manufacturing method comprising a step of obtaining silica gel in which the percentage of the integral of a peak in the region of -94 ppm to -66 ppm relative to the integral of a peak in the region of -127 ppm to -66 ppm of a Si-NMR spectrum is within a range of 20% to 80%.

16. A manufacturing method in which, in paragraph 15, the content of the precursor of silica gel in the precursor solution is 2 to 80 wt%, and the weight ratio of the vaporizable material to 100 wt% of the precursor is in the range of 20 to 2,000 wt%.

17. A manufacturing method in which the molal concentration of the catalyst for the volatile substance in the precursor solution is in the range of 0.005 to 10 in the 16th paragraph.

18. A manufacturing method according to claim 16 or 17, wherein polymerization is performed at a temperature in the range of 10°C to 40°C.

19. A manufacturing method according to any one of claims 15 to 18, comprising a first step of first polymerizing a precursor solution to obtain a prepolymer and a second step of polymerizing the prepolymer to obtain silica gel, wherein the second step is performed in the presence of inorganic fibers.

20. A manufacturing method in which polymerization is performed in the presence of 10 to 500 parts by weight of inorganic fibers relative to 100 parts by weight of a precursor or prepolymer of silica gel in paragraph 19.

21. A heat absorbing device comprising a composite material according to any one of claims 1 to 14; and a case containing the composite material.

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