Fire extinguishing composition for an electric wire cap or busbar tube applied to a wire end portion in an electrical distribution panel, and a method for preparing same

Abstract

The present application relates to a fire extinguishing composition for a wire cap or busbar tube applied to the end of a wire in an electrical distribution panel, and a method for manufacturing the same.

Description

Technology Field

[0001] The present invention relates to a fire extinguishing composition for a wire cap or busbar tube applied to the end of a wire in an electrical distribution board, and a method for manufacturing the same. Background Technology

[0002] Recently, as the high integration and high output of industrial facilities and electrical and electronic systems have accelerated, the risk of fire has been continuously increasing. In particular, in facilities where numerous electrical components and wiring are densely packed, such as electrical distribution panels, control panels, and various power distribution devices, the likelihood of localized overheating or arcing is rising due to increased current density, increased heat generation, and the complexity of the operating environment. Although these electrical anomalies initially occur in a form that is difficult to detect from the outside, they can rapidly escalate into fires once a certain critical threshold is exceeded. This is recognized as a serious social problem, as it can lead not only to damage to the facilities themselves but also to casualties and large-scale economic losses.

[0003] Furthermore, due to the recent proliferation of unmanned and automated facilities, there is an increasing number of cases where electrical equipment is operated without supervision for extended periods, creating an environment where immediate response to fires is difficult. Existing fire response methods often rely on reactive measures, such as using fire extinguishers or activating automatic fire suppression systems only after the fire has progressed beyond a certain scale, which limits their ability to effectively suppress fires in their early stages. In particular, fires occurring in enclosed and confined spaces, such as the interior of electrical equipment, tend to spread rapidly if the initial suppression is missed; therefore, the importance of early fire suppression and localized firefighting is being further emphasized.

[0004] Against this backdrop, there is a growing need for fire prevention and suppression technologies to evolve beyond simply extinguishing fires after they occur, moving toward the ability to contain flames from the early stages in areas with a high risk of fire. In other words, there is an increasing demand for technologies that can rapidly suppress fires without the need for separate external devices or human intervention by imbuing fire extinguishing functions directly into equipment components where fire risks are ever-present. This is recognized as an essential technical challenge for fundamentally enhancing equipment safety and minimizing damage caused by fire.

[0005] Generally, an electrical distribution board is a structure in which various electrical equipment and power control devices are densely installed, and numerous wires, busbars, circuit breakers, relays, and terminals are arranged within a limited space. Inside such an electrical distribution board, there is a high possibility that localized overheating or arcing will occur at the ends of wires or busbar connections due to causes such as overcurrent, poor contact, insulation degradation, and heat accumulation from the external environment, and cases of initial fires resulting from this are continuously being reported.

[0006] In particular, due to the structural characteristics where stripped conductors are directly connected to terminals or busbars, the ends of power lines have relatively weak insulation reliability and are areas prone to heat concentration caused by minute increases in contact resistance, vibrations, or moisture ingress. Given that fires originating at these ends can spread rapidly within the switchboard and lead to equipment damage, prolonged power outages, and serious industrial accidents, prevention and early firefighting technologies are of paramount importance.

[0007] Meanwhile, conventional fire extinguishing technologies have primarily evolved as means to suppress fires after they occur. Representative examples include extinguishing agents charged into portable or stationary fire extinguishers, insulation or flame-retardant materials applied to the exteriors of buildings or facilities, and specialized fire extinguishing systems applied to server rooms or large electrical rooms. These existing extinguishing agents are provided in forms such as water, powder, carbon dioxide, halogen-based, or inert gas-based extinguishing agents, and are used by being sprayed or released from the outside once the flames have grown beyond a certain size.

[0008] However, most of these conventional fire extinguishing agents and systems are designed for relatively large spaces or focus on extinguishing fires after they occur, so they have structural and functional limitations in actively suppressing initial fires that occur in narrow and enclosed spaces, such as the ends of wires inside electrical distribution panels. In particular, fire extinguishing agents for general fire extinguishers are not designed to be applied to small parts such as wire caps or the inside of busbar tubes, and insulation or flame retardant materials are intended only to delay flame spread or block heat, and do not perform the function of immediately releasing the extinguishing agent at the point of fire to suppress the initial fire.

[0009] In addition, special fire extinguishing agents or automatic fire extinguishing systems are typically installed for the entire distribution panel or specific sections, so there are issues such as installation costs, space constraints, and structural complexity when applying them directly to localized areas like individual wire ends or busbar connections. Furthermore, since these systems operate after fire detection, there are limitations in preemptively suppressing initial fires caused by micro-arc or localized overheating that occur before detection.

[0010] As such, in the prior art, fire extinguishing agents have been applied only as components of general fire extinguishers, insulation materials, or special fire extinguishing systems; there has been no substantial consideration or disclosure of compositions or structures for imparting fire extinguishing functions to the wire caps or busbar tubes themselves, which are directly applied to the ends of wires within electrical distribution panels. In other words, the concept of immediately suppressing flames by having the part itself contain a fire extinguishing agent and release it at the initial stage of a fire—based on the premise that a fire may occur at the end of a wire—has not been sufficiently proposed in the prior art.

[0011] Therefore, there has been a continuous technical demand for a new type of fire extinguishing composition that is suitable for a specific application environment, such as the end of a wire in an electrical distribution panel, while maintaining electrical insulation, being able to be stably placed even in confined spaces, and being able to extinguish an initial fire by locally releasing a fire extinguishing agent when a fire occurs. Prior art literature

[0012] Korean Registered Patent Document No. 10-1147495 The problem to be solved

[0013] The present invention aims to solve the technical problem of effectively reducing the risk of fire occurring at wire ends or busbar connection points within an electrical distribution panel. As previously explained, the interior of an electrical distribution panel has a structure in which wires, busbars, terminals, and various electrical components are densely packed. In particular, wire ends are vulnerable areas where localized overheating and initial fires frequently occur due to increased contact resistance, insulation degradation, and arc generation. However, most conventional fire extinguishing technologies rely on using fire extinguishers from the outside after a fire occurs or on automatic fire extinguishing systems targeting the entire distribution panel. Consequently, there have been limitations in rapidly and effectively suppressing initial fires occurring in localized areas, such as wire ends.

[0014] In addition, most existing fire extinguishing agents are applied to general fire extinguishers, building insulation materials, or special fire extinguishing systems for large electrical facilities, and there have been few cases where they are designed to be applied inside small electrical components, such as wire caps or busbar tubes, to act directly at the point of fire. In particular, fire extinguishing compositions applied inside electrical distribution panels need to meet complex requirements, such as maintaining electrical insulation, remaining stable even in confined spaces, existing without leakage or performance degradation under normal conditions, and operating selectively only when a fire occurs; however, technology that simultaneously satisfies these requirements has not been sufficiently proposed.

[0015] Accordingly, one objective of the present invention is to provide a fire extinguishing composition capable of suppressing flames by locally releasing a fire extinguishing agent at the initial stage of a fire, by imparting a fire extinguishing function to the wire cap or busbar tube itself applied to the wire end portion within an electrical distribution panel. Specifically, the present invention presents a technical means for stably retaining a fire extinguishing agent within the pores of a silica aerogel having a porous structure, thereby allowing the agent to be released through changes in the pore structure or collapse of the silica aerogel upon a temperature rise caused by a fire. Through this, the objective is to enable the spontaneous suppression of initial fires occurring at the wire end portion without the need for a separate detection device or external drive.

[0016] Ultimately, the purpose of the present invention is to provide a fire extinguishing composition and a method for manufacturing the same that can be directly applied to fire-vulnerable areas, such as wire ends within electrical distribution panels, thereby moving away from the reactive fire suppression methods of conventional technology and presenting a new technical solution capable of actively suppressing fires at the initial stage of occurrence. means of solving the problem

[0017] One embodiment of the present specification provides a fire extinguishing composition for a wire cap or busbar tube applied to the end of a wire in an electrical distribution board, wherein the fire extinguishing composition comprises a silica aerogel and a fire extinguishing agent physically supported in the pores of the silica aerogel, and wherein the silica aerogel has an average particle size of 0.3 μm or more and 50 μm or less, a porosity of 85% or more and 95% or less, and an average pore diameter of 50 nm or more and 100 nm or less.

[0018] In one embodiment of the present specification, the fire extinguishing agent is supported on a silica aerogel, thereby providing a fire extinguishing composition that is a non-conductive fire extinguishing agent released by heat.

[0019] In one embodiment of the present specification, the fire extinguishing composition is provided in which the fire extinguishing agent is released as the pore structure of the silica aerogel collapses due to a temperature rise caused by a fire.

[0020] In one embodiment of the present specification, the extinguishing agent is a non-conductive extinguishing agent having electrical insulation properties, and provides a extinguishing composition comprising at least one selected from an inert gas, a halogenated hydrocarbon-based extinguishing agent, a bicarbonate-based extinguishing agent, a phosphorus-based flame retardant, and a nitrogen-based flame retardant.

[0021] In one embodiment of the present specification, a fire extinguishing composition is provided in which the fire extinguishing agent comprises at least 1 part by weight and no more than 40 parts by weight based on 100 parts by weight of the silica aerogel.

[0022] In one embodiment of the present specification, the fire extinguishing composition is provided, characterized in that it further comprises a binder or a dispersant to improve the dispersion stability of the silica aerogel.

[0023] The present application provides a method for preparing a fire extinguishing composition comprising the steps of: preparing silica aerogel powder; and mixing and loading a fire extinguishing agent onto the silica aerogel powder; wherein the loading step is a physical adsorption-based loading performed by stirring at a temperature of 10°C or higher and 30°C or lower, at a speed of 300 rpm or higher and 800 rpm or lower, and for 30 minutes to 1 hour.

[0024] In the present application, the step of preparing the silica aerogel powder comprises: preparing a water glass emulsion solution by mixing and stirring water glass, a surfactant, and an organic solvent; forming a silica wet gel by adding and stirring acetic acid and isopropanol to the emulsion solution; and separating and recovering the silica wet gel to form spherical silica aerogel powder, thereby providing a method for preparing a fire extinguishing composition.

[0025] In the present application, a method for preparing a extinguishing composition is provided, wherein in the step of preparing the water glass emulsion solution, the stirring rpm is 5000 rpm or more and 8000 rpm or less, and the stirring time is 5 minutes or more and 15 minutes or less.

[0026] The present application provides a method for preparing a digestion composition in which the formed silica aerogel powder has an average particle size of 0.3 μm or more and 50 μm or less, a porosity of 85% or more and 95% or less, and an average pore diameter of 50 nm or more and 100 nm or less.

[0027] In the present application, the step of separating and recovering the silica wet gel to form spherical silica aerogel powder comprises: the step of separating and recovering the silica wet gel; and the step of washing and drying the recovered wet gel, thereby providing a method for preparing a extinguishing composition. Effects of the invention

[0028] According to the present invention, by applying silica aerogel to a fire extinguishing composition for wire caps or busbar tubes applied to the ends of wires within an electrical distribution panel and loading a fire extinguishing agent within its pores, the effect of enabling localized and automatic fire extinguishing without the need for external power cutoff or separate fire extinguishing equipment in the event of a fire is provided. In particular, by using silica aerogel in which the average particle size, porosity, and average pore diameter are controlled within a specific range, the loading efficiency and storage stability of the fire extinguishing agent are improved, and the deterioration of fire extinguishing performance can be effectively prevented even during long-term use.

[0029] In addition, the fire extinguishing composition of the present invention is designed so that when the temperature rises due to a fire, the pore structure of the silica aerogel collapses and the contained fire extinguishing agent is released, thereby inducing immediate fire extinguishing action at the initial ignition stage. As a result, the spread of fire caused by local overheating, sparks, arcing, etc., which frequently occur inside electrical distribution panels can be effectively suppressed, and by using a non-conductive material as the fire extinguishing agent, the possibility of electric shock, short circuit, and secondary electrical accidents can be significantly reduced.

[0030] Furthermore, according to the manufacturing method of the present invention, silica aerogel powder is manufactured under relatively low temperature and low energy conditions, and a fire extinguishing agent is loaded via a physical adsorption method, thereby having the advantages of a simple manufacturing process and excellent reproducibility. As a result, mass production and industrial application are easy, and unlike conventional general fire extinguishers, insulation materials, or special fire extinguishing systems, by providing a fire extinguishing composition that can be directly applied to the special environment of the wire ends inside electrical distribution panels, it has the effect of dramatically improving the fire safety of electrical facilities. Brief explanation of the drawing

[0031] Figure 1 is a schematic diagram showing the process of manufacturing silica aerogel. FIG. 2 is a diagram showing a method of molding a wire terminal cap to which the fire extinguishing composition of the present application is applied. Specific details for implementing the invention

[0032] Unless otherwise specifically defined, the terms used in this specification have the meanings commonly understood in the relevant technical field. However, to aid in understanding the present invention, representative terms are defined as follows.

[0033] In this specification, the term “electrical distribution board” refers to an electrical facility for distributing, controlling, or protecting power, and includes all forms of electrical distribution boards, distribution boards, control boards, and similar electrical facilities, such as circuit breakers, busbars, wires, terminals, connections, etc.

[0034] The term “end of wire” refers to an end or termination of a wire that is electrically connected or can be electrically connected to a terminal, busbar, circuit breaker, or other electrical connection member within an electrical distribution panel, and is a concept that includes both the part where the insulation has been removed and the adjacent area.

[0035] The term “wire cap” refers to a member mounted on the end of a wire to protect or insulate the end of the wire, including a cap form, a molding form, or a filling form, and includes any structure capable of performing electrical insulation, mechanical protection, or fire safety functions.

[0036] The term “busbar tube” refers to a tubular or sheathed member that surrounds or encloses a busbar within an electrical distribution panel, and is used for the purpose of insulation, protection, or fire safety of the busbar, and includes a tubular structure formed of resin, rubber, thermoplastic, or thermosetting material.

[0037] The term “fire extinguishing composition” means a composition having a function to suppress or block combustion when a fire occurs, and means a substance or a mixture of substances capable of performing at least one of flame suppression, oxygen blockage, heat absorption, or inhibition of combustion reaction.

[0038] “Silica aerogel” refers to an ultra-lightweight, high-porosity material having a porous structure and composed mainly of silica (SiO₂), and means a high-specific-surface-area structure containing nanometer-sized pores, and in the present invention includes spherical or powder forms.

[0039] “Pores” refers to fine pores formed within the silica aerogel, and “pore structure” refers to structural characteristics including the size, distribution, and connectivity of these pores.

[0040] “Carrying” means that a fire extinguishing agent is maintained in a state of being physically adsorbed, infiltrated, or captured inside or on the pores or surface of a silica aerogel, and is not limited to chemical bonding but includes cases by physical adsorption.

[0041] The term “fire extinguishing agent” refers to an active ingredient intended to suppress or block a combustion reaction when a fire occurs, and includes non-conductive substances and is a concept that includes gaseous, liquid, or solid forms.

[0042] “Non-conductivity” means a characteristic that has very low electrical conductivity and does not substantially generate a flow of current, and includes a characteristic that does not cause a short circuit or electric shock risk when applied in an electrical distribution panel.

[0043] “Physical adsorption-based loading” refers to a loading method in which a fire extinguishing agent is adsorbed or captured by the pore structure and surface characteristics of silica aerogel without chemical reactions or covalent bonds.

[0044] “Agitation” refers to a process of applying rotation or shear force for uniform dispersion or loading of a mixture, and is a concept that includes rotational speed (rpm), time, and temperature conditions.

[0045] The present application will be described in more detail below.

[0046] One embodiment of the present application provides a fire extinguishing composition for a wire cap or busbar tube applied to the end of a wire in an electrical distribution board, wherein the fire extinguishing composition comprises a silica aerogel and a fire extinguishing agent physically supported in the pores of the silica aerogel, and wherein the silica aerogel has an average particle size of 0.3 μm or more and 50 μm or less, a porosity of 85% or more and 95% or less, and an average pore diameter of 50 nm or more and 100 nm or less.

[0047] The fire extinguishing composition comprises a silica aerogel having a porous structure, wherein a fire extinguishing agent is supported within the internal pores of the silica aerogel. The fire extinguishing agent exists in a state where it is physically adsorbed or trapped within the pores of the silica aerogel, maintaining stability without leaking out under normal conditions, and can be selectively released by heat in the event of a fire. Due to this structure, the fire extinguishing composition can perform an immediate fire extinguishing function while maintaining long-term stability even in confined spaces, such as the ends of electrical wires within an electrical distribution panel.

[0048] The above silica aerogel may be provided in the form of powder or spherical particles with an average particle size of 0.3 μm or more and 50 μm or less. This particle size range allows the fire extinguishing composition to be uniformly filled or dispersed inside the wire cap or busbar tube, thereby ensuring uniform fire extinguishing performance across the entire area without being concentrated in specific parts. If the average particle size is less than 0.3 μm, dust generation or reduced handling may occur, and if it exceeds 50 μm, the loading efficiency of the fire extinguishing agent within the pores may decrease or the filling density may decrease; therefore, it is desirable to control it within the above range.

[0049] In addition, the silica aerogel is formed with a porosity of 85% or more and 95% or less, thereby securing a very high pore volume and enabling it to sufficiently support a fire extinguishing agent. If the porosity is less than 85%, the amount of fire extinguishing agent supported is limited, which may lead to a decrease in fire extinguishing performance; conversely, if it exceeds 95%, structural strength is reduced, raising concerns that the pore structure may collapse during handling or use. Therefore, a silica aerogel having a porosity within the above range can effectively ensure a balance between support stability and structural stability.

[0050] Furthermore, it is preferable that the average pore diameter of the silica aerogel be formed to be between 50 nm and 100 nm. This pore diameter range allows the fire extinguishing agent to be stably maintained within the pores while enabling rapid release through the collapse or deformation of the pore structure upon a temperature rise caused by a fire. Since the penetration and release of the fire extinguishing agent may be limited if the average pore diameter is less than 50 nm, and the possibility of leakage of the fire extinguishing agent during normal operation may increase if it exceeds 100 nm, the above range is particularly preferred.

[0051] In this way, the fire extinguishing composition of the present invention can simultaneously achieve structural and functional effects by progressively limiting the particle size, porosity, and pore diameter of the silica aerogel, thereby maintaining a stable support state in high-risk and confined spaces such as the ends of wires within electrical distribution panels, while selectively releasing a fire extinguishing agent only when a fire occurs.

[0052] The fire extinguishing agent is provided in a state supported within the pores of silica aerogel and remains stable under normal operating conditions without being easily released by the external environment. As a non-conductive material with electrical insulation properties, the fire extinguishing agent does not induce current flow even when applied to wire ends or near busbars within electrical distribution panels, nor does it cause electrical accidents such as short circuits or electric shocks. Accordingly, the fire extinguishing composition of the present invention ensures structural safety that allows for direct application to electrical facilities.

[0053] The fire extinguishing composition according to the present invention is designed to be actively activated by heat when a fire occurs. When a fire occurs due to poor contact, an arc, or overheating at the end of a wire, a local temperature rise is transmitted to the silica aerogel, and as the temperature reaches above a certain level, the porous pore structure of the silica aerogel gradually weakens or collapses. In this process, the fire extinguishing agent that was physically adsorbed or trapped inside the pores is released to the outside, and an automatic fire extinguishing reaction is induced without a separate ignition device or mechanical drive unit.

[0054] The breakdown of the pore structure of the above silica aerogel is not limited to chemical decomposition but may occur due to structural deformation, shrinkage, or a decrease in bonding strength caused by heat, and such changes prevent the extinguishing agent from being retained inside the pores, thereby promoting its release. In particular, in the present invention, the average pore diameter and porosity of the silica aerogel are controlled so that the extinguishing agent is stably supported under normal conditions, while the release reaction is not delayed in the event of a rapid temperature rise caused by a fire.

[0055] The released extinguishing agent rapidly suppresses the initial fire by reducing the oxygen concentration around the flame, inhibiting the combustion reaction, or blocking the propagation of the flame. At this time, since the extinguishing agent is a non-conductive material, electrical insulation properties are maintained during the extinguishing process, which can effectively prevent additional damage to the inside of the electrical distribution panel or the occurrence of secondary accidents.

[0056] Thus, the fire extinguishing composition of the present invention provides the effect of rapidly and safely controlling initial fires occurring at the ends of wires within electrical distribution panels by implementing a thermal responsive fire extinguishing mechanism that selectively releases a fire extinguishing agent only when a fire occurs, through the pore structure of silica aerogel.

[0057] The above-mentioned fire extinguishing agent is a non-conductive fire extinguishing agent with electrical insulation properties. When applied within an electrical distribution panel, it does not induce the flow of current and possesses the characteristic of not causing short circuits, electric shocks, or additional electrical damage during the fire extinguishing process. This non-conductive characteristic is an important technical element that enables the fire extinguishing composition of the present invention to be directly applied to electrical equipment where an energized state can be maintained, such as wire ends, busbars, and terminals.

[0058] In one embodiment, the fire extinguishing agent may include an inert gas. The inert gas performs the function of suppressing the combustion reaction by reducing the oxygen concentration around the flame, and may include, typically, nitrogen (N₂), argon (Ar), helium (He), carbon dioxide (CO₂), or a mixture thereof. Such an inert gas does not have electrical conductivity and is supported in a trapped state within the pores of the silica aerogel, and is released upon the occurrence of a fire to effectively suppress the initial flame.

[0059] In another embodiment, the extinguishing agent may include a halogenated hydrocarbon-based extinguishing agent. The halogenated hydrocarbon-based extinguishing agent performs the function of suppressing flame propagation by capturing radicals of combustion reactions, and may include, for example, halon-based extinguishing agents, fluorinated hydrocarbon (HFC)-based extinguishing agents, fluoroketone-based extinguishing agents, or derivatives thereof. Such extinguishing agents exhibit high extinguishing efficiency even in small amounts and maintain non-conductivity, making them suitable for electrical equipment fires.

[0060] In another embodiment, the fire extinguishing agent may include a bicarbonate-based fire extinguishing agent. The bicarbonate-based fire extinguishing agent decomposes upon heat to generate carbon dioxide and simultaneously absorbs the heat of the flame to suppress the combustion reaction. For example, sodium bicarbonate, potassium bicarbonate, or a mixture thereof may be used, and these materials can be supported in a solid state within the pores of the silica aerogel and maintained stably.

[0061] In addition, the fire extinguishing agent may include a phosphorus-based flame retardant. The phosphorus-based flame retardant forms phosphoric acid or a phosphoric acid-based compound upon thermal decomposition, thereby forming a protective layer on the combustion surface and inhibiting the combustion reaction. Specifically, it may include ammonium polyphosphate, a phosphate ester-based compound, a phosphate-based flame retardant, or a combination thereof, and such materials exhibit high affinity with the pore structure of silica aerogel while maintaining non-conductivity.

[0062] In another embodiment, the fire extinguishing agent may include a nitrogen-based flame retardant. The nitrogen-based flame retardant exhibits a fire extinguishing effect by releasing nitrogen gas upon decomposition by heat or by generating a non-combustible gas that inhibits combustion reactions. For example, it may include melamine, melamine derivatives, melamine cyanurate, or other nitrogen-containing compounds, which are supported on silica aerogel and are suitable for constituting a thermal responsive fire extinguishing system.

[0063] In the present invention, at least one selected from the inert gas, halogenated hydrocarbon-based fire extinguishing agent, bicarbonate-based fire extinguishing agent, phosphorus-based flame retardant, and nitrogen-based flame retardant may be used alone, or, if necessary, two or more may be used in combination. Through such combination, at least one fire extinguishing mechanism among oxygen blocking, radical inhibition, heat absorption, and protective layer formation can be configured to function in combination.

[0064] In this way, the fire extinguishing composition of the present invention enables stable and rapid fire suppression even in high-risk electrical environments, such as wire ends within electrical distribution panels, by encapsulating various series of non-conductive fire extinguishing agents within the pores of silica aerogel.

[0065] The above-mentioned fire extinguishing composition may further include a binder or a dispersant to improve the dispersion stability of the silica aerogel. The binder or dispersant suppresses aggregation between silica aerogel particles and ensures that the fire extinguishing composition is uniformly distributed during the process of being applied inside a wire cap or busbar tube, thereby playing a role in minimizing variations in fire extinguishing performance.

[0066] In one embodiment, the binder may function to improve the adhesion between the silica aerogel particles and the inner wall of a wire cap or busbar tube. The binder may include organic or inorganic materials, for example, silicone-based binders, acrylic resins, epoxy resins, polyurethane resins, or mixtures thereof. Such a binder can prevent the fire extinguishing composition from detaching or separating due to vibration, thermal changes, or external impact during long-term use, without impairing the porous structure of the silica aerogel.

[0067] In another embodiment, the dispersant may serve to suppress local aggregation or sedimentation by ensuring that silica aerogel particles are uniformly dispersed within the composition. The dispersant may include nonionic, anionic, or cationic surfactants, and may include, for example, sorbitan ester-based, polyoxyethylene-based, polycarboxylate-based, siloxane-based dispersants, or mixtures thereof.

[0068] In addition, it is desirable that the binder or dispersant be selected so as not to have a negative effect on the release characteristics of the fire extinguishing agent supported inside the pores of the silica aerogel. That is, the binder or dispersant may be composed of a material that maintains the structural stability of the silica aerogel under normal conditions, while not causing the collapse of the pore structure of the silica aerogel or hindering the fire extinguishing agent release mechanism when the temperature rises due to a fire.

[0069] In this way, by additionally including a binder or a dispersant in the fire extinguishing composition of the present invention, the dispersion stability, applicability, and long-term reliability of the silica aerogel-based fire extinguishing composition can be simultaneously improved, and uniform and stable fire extinguishing performance can be achieved even in confined spaces such as wire ends and busbar tubes within electrical distribution panels.

[0070] In the above fire extinguishing composition, the fire extinguishing agent may be included in a range of 1 part by weight or more and 40 parts by weight or less, based on 100 parts by weight of silica aerogel. The above range is set so that sufficient fire extinguishing performance can be achieved in the event of a fire while maintaining the pore structure of the silica aerogel.

[0071] If the content of the above-mentioned extinguishing agent is less than 1 part by weight per 100 parts by weight of silica aerogel, the absolute amount of extinguishing agent contained within the pores is insufficient, and the amount of extinguishing agent released in the event of a fire may not be sufficient, which may lead to a decrease in the initial fire extinguishing effect. In particular, it is important to secure a minimum amount of extinguishing agent in environments where localized fires can spread rapidly, such as at the ends of wires within electrical distribution panels.

[0072] On the other hand, if the content of the fire extinguishing agent exceeds 40 parts by weight per 100 parts by weight of silica aerogel, the pores of the silica aerogel may be excessively filled, causing the pore structure to be partially closed, or the possibility of the fire extinguishing agent leaking even under normal usage conditions may increase. In addition, excessive loading of the fire extinguishing agent may reduce the dispersion stability or structural strength of the silica aerogel, thereby causing a decrease in the performance of the fire extinguishing composition during long-term use.

[0073] In one embodiment, the fire extinguishing agent may preferably be included in a range of 5 parts by weight or more and 30 parts by weight or less per 100 parts by weight of silica aerogel, and in another embodiment, it may be included in a range of 10 parts by weight or more and 25 parts by weight or less. In this range, the load stability of the fire extinguishing agent and the discharge efficiency when a fire occurs are balanced, so that the initial fire extinguishing performance can be further improved.

[0074] In this way, the fire extinguishing composition of the present invention controls the content of the fire extinguishing agent relative to the silica aerogel to a specific range, thereby maintaining a stable loading state under normal conditions while allowing for the rapid and sufficient release of the fire extinguishing agent in the event of a fire, thus providing the effect of effectively improving fire safety at the ends of electrical wires within the electrical distribution panel.

[0075] One embodiment of the present application provides a method for preparing a fire extinguishing composition comprising the steps of: preparing silica aerogel powder; and mixing and loading a fire extinguishing agent onto the silica aerogel powder; wherein the loading step is a physical adsorption-based loading performed by stirring at a temperature of 10°C or higher and 30°C or lower, at a speed of 300 rpm or higher and 800 rpm or lower, and for 30 minutes to 1 hour.

[0076] In particular, the fire extinguishing composition according to the present invention provides the effect of stably storing the fire extinguishing agent without damaging its inherent chemical structure and electrical insulation properties by supporting the fire extinguishing agent within the pores of silica aerogel via a physical adsorption method rather than chemical bonding. This physical adsorption-based support ensures that the fire extinguishing agent is stably maintained within the high-porous structure of the silica aerogel under ambient temperature and normal usage environments, thereby preventing leakage or premature release. Furthermore, in the event of a rapid temperature rise caused by a fire, the fire extinguishing agent is rapidly released through changes in the pore structure or collapse of the silica aerogel. Accordingly, the present invention enables spontaneous and selective fire extinguishing action at the location of a fire without the need for a separate operating device or external stimuli, and has a significant effect of effectively preventing problems such as increased reactivity, reduced long-term storage stability, and deterioration of electrical properties that may occur in chemical support methods.

[0077] A method for preparing a fire extinguishing composition according to the present invention comprises the steps of preparing silica aerogel powder and mixing and loading a fire extinguishing agent onto the silica aerogel powder. By this method, a fire extinguishing composition in which a fire extinguishing agent is stably loaded inside the pores of a silica aerogel having a porous structure can be provided.

[0078] First, in the step of manufacturing silica aerogel powder, a water glass emulsion solution is prepared by mixing and stirring water glass, a surfactant, and an organic solvent. The process for manufacturing silica aerogel powder specifically can be seen in Fig. 1. The surfactant is used to suppress phase separation between the water glass and the organic solvent and to form a uniform emulsion state, thereby ensuring the stability of the emulsion and enabling the formation of spherical silica particles in subsequent processes. At this stage, the stirring conditions have a significant influence on the micronization and homogenization of the emulsion.

[0079] The surfactant used in the step of preparing the above water glass emulsion solution is intended to reduce the interfacial tension between the water glass and the organic solvent to form a stable emulsion state, and may include nonionic, anionic, or cationic surfactants. For example, sorbitan ester-based surfactants, polyoxyethylene-based surfactants, alkylphenol ethoxylate-based surfactants, fatty acid ester-based surfactants, or mixtures thereof may be used, and such surfactants facilitate the formation of spherical silica wet gels by uniformly controlling the size of the emulsion particles during the stirring process.

[0080] In addition, the organic solvent plays a role in promoting emulsion formation by providing a phase separation environment with water glass, and for example, hexane, heptane, cyclohexane, toluene, isooctane, or a mixture thereof may be used, and if necessary, an alcohol-based solvent or an ester-based solvent may be used together as an auxiliary solvent.

[0081] In one embodiment, the stirring speed in the step of preparing the water glass emulsion solution may be 5,000 rpm or more and 8,000 rpm or less, and the stirring time may be 5 minutes or more and 15 minutes or less. If the stirring speed is less than 5,000 rpm or the stirring time is less than 5 minutes, the emulsion particles may not be sufficiently fined, and the particle size distribution may become non-uniform; conversely, if the stirring speed exceeds 8,000 rpm or exceeds 15 minutes, the emulsion may become unstable due to excessive shear force. Therefore, a uniform emulsion solution can be stably formed through stirring conditions within the above range.

[0082] Next, a silica wet gel is formed by adding acetic acid and isopropanol to the emulsion solution and stirring. The acetic acid serves to induce the hydrolysis and condensation reactions of the water glass, while the isopropanol serves to control the reaction rate and improve the uniformity of the gel structure. The silica wet gel formed at this stage forms a porous structure while maintaining a spherical shape.

[0083] Subsequently, the above silica wet gel is separated and recovered, and then spherical silica aerogel powder is formed through washing and drying steps. The washing step is intended to remove residual reaction by-products or solvent, and the drying step is intended to remove the solvent inside the wet gel to convert it into a silica aerogel that maintains a porous structure. Through this process, silica aerogel powder can be obtained having an average particle size of 0.3 μm or more and 50 μm or less, a porosity of 85% or more and 95% or less, and an average pore diameter of 50 nm or more and 100 nm or less.

[0084] Meanwhile, the step of mixing and loading a fire extinguishing agent onto the silica aerogel powder prepared as described above is performed based on physical adsorption. In one embodiment, the loading step is performed in a temperature range of 10°C or higher and 30°C or lower, and can be carried out by stirring at a stirring speed of 300 rpm or higher and 800 rpm or lower for 30 minutes to 1 hour. The temperature range is intended to allow the fire extinguishing agent to stably penetrate into the pores of the silica aerogel while preventing changes in the physical properties or premature volatilization of the fire extinguishing agent.

[0085] In addition, if the stirring speed is less than 300 rpm or the stirring time is less than 30 minutes, the extinguishing agent may not be sufficiently loaded inside the pores of the silica aerogel; conversely, if the stirring speed exceeds 800 rpm or exceeds 1 hour, there is a risk that the pore structure of the silica aerogel may be damaged or the extinguishing agent may be unnecessarily lost. Therefore, through stirring conditions within the above range, the extinguishing agent can be uniformly loaded while maintaining the pore structure of the silica aerogel.

[0086] Thus, the manufacturing method of the present invention provides the effect of reproducibly manufacturing a fire extinguishing composition having structural stability and excellent fire extinguishing performance suitable for application to the wire ends within an electrical distribution panel by systematically controlling the step of manufacturing the silica aerogel and the step of loading the fire extinguishing agent.

[0087] FIG. 2 is a diagram showing a method of molding a wire terminal cap to which the fire extinguishing composition of the present application is applied. That is, the present application is a method in which the fire extinguishing composition is applied to a wire terminal cap, etc. Specifically, the wire terminal cap to which the fire extinguishing composition of the present application is applied can be molded using an insulating resin composition as a base material, and can be manufactured, for example, by injection molding or compression molding.

[0088] Specifically, the fire extinguishing composition is mixed with a thermoplastic or thermosetting insulating resin to produce a molding compound, which is then poured into a mold and molded into a cap shape capable of accommodating the end portion of a wire. At this time, the fire extinguishing composition may be molded to be uniformly dispersed throughout the terminal cap or selectively placed in an area adjacent to the wire connection part where the possibility of fire is high. After molding, a wire terminal cap of the final shape is obtained through a cooling or curing process. Under normal operating conditions, the terminal cap performs electrical insulation and mechanical protection functions, and in the event of a fire, the silica aerogel-supported fire extinguishing agent contained therein is released by heat to effectively suppress the initial fire at the end portion of the wire.

[0089] When considering mechanical properties, TPV, TPU, SEBS, and PVC materials are representative materials applicable as wire terminal caps. These materials are suitable for terminal caps because they all have excellent electrical insulation and possess elasticity and durability capable of protecting the wire ends from external impacts and environmental factors. In particular, they have the advantage of being able to adjust hardness (in the range of approximately 40 to 90 based on Shore A), ensuring a tight fit according to wire specifications, and being able to be manufactured in various shapes through injection molding.

[0090] Specifically, TPV and TPU materials have high tensile and tear strengths and excellent bending characteristics, making them suitable for electrical distribution panel environments where repetitive vibration or thermal expansion occurs. TPU materials have excellent wear resistance and heat resistance (approximately 140°C or higher), allowing them to maintain stable performance even in high-temperature environments, while TPV materials are advantageous for applications requiring long-term reliability due to their relatively low specific gravity and excellent weather resistance. Meanwhile, SEBS materials have high elongation and excellent low-temperature bending characteristics, making them suitable for protecting wire ends where flexibility is required, and PVC materials have excellent cost competitiveness and processability, allowing them to be widely applied to general-purpose wire terminal caps. Therefore, the fire extinguishing composition of the present application can be effectively utilized by being composited with these thermoplastic resin materials to provide additional fire extinguishing functions in the event of a fire while maintaining the basic insulation and mechanical performance of the wire terminal cap.

[0091] <Preparation Example>

[0092] <Example 1>

[0093] 1. Preparation of silica aerogel

[0094] A water glass emulsion solution in which the water glass was finely dispersed within a continuous phase was prepared by mixing commercial water glass, Span 80 as a surfactant, and hexane as an organic solvent, and then stirring the mixture using a homogenizer at a rotational speed of approximately 6,000 rpm for 10 minutes. During this process, the homogenization conditions were controlled to form uniform droplet sizes of the emulsion, thereby ensuring stable sphericity and particle size distribution of the silica particles produced thereafter.

[0095] Next, acetic acid and isopropanol were sequentially added to the water glass emulsion solution, and stirring was continued to induce hydrolysis and condensation reactions of the water glass, thereby forming a silica wet gel. The formed silica wet gel grew while maintaining the shape of the emulsion droplet to acquire a spherical structure. Subsequently, the silica wet gel was separated and recovered, followed by a washing process to remove remaining reactants and impurities, and the washed wet gel was dried to produce spherical silica aerogel powder having a porous structure. The silica aerogel powder produced according to the above method satisfied the following: an average particle size of 10㎛ to 20㎛ or less, a porosity of 85% to 90%, and an average pore diameter of 50 nm or more to 100 nm or less.

[0096] 2. Fire extinguishing agent mixture loading

[0097] After adding a fire extinguishing agent to the silica aerogel powder prepared as described above, the mixture was mixed and stirred at a stirring speed of 500 rpm for about 1 hour at room temperature of about 25°C to support the fire extinguishing agent so that it is physically adsorbed into the porous pore structure of the silica aerogel. At this time, due to the high porosity and fine average pore diameter of the silica aerogel, the fire extinguishing agent effectively penetrates and is captured inside the pores. Since the agent is supported based on physical adsorption rather than chemical bonding, the original chemical properties of the fire extinguishing agent are maintained, and a structure is formed that can be selectively released by heat.

[0098] The extinguishing agent contained nitrogen (N₂) as an inert gas, heptafluoropropane (HFC-227ea) as a halogenated hydrocarbon extinguishing agent, and sodium bicarbonate (NaHCO₃) as a bicarbonate extinguishing agent. In addition, it contained ammonium polyphosphate (APP) as a phosphorus-based flame retardant and melamine as a nitrogen-based flame retardant.

[0099] Specifically, the process began with the step of first introducing solid sodium bicarbonate, ammonium polyphosphate, and melamine into a mixer and then uniformly mixing them to form a solid mixture. At this time, the solid mixture may undergo grinding and sieving processes to minimize particle size variation, thereby controlling the average particle size to be between 1 μm and 20 μm. Subsequently, heptafluoropropane, a halogenated hydrocarbon-based fire extinguishing agent, was added to the solid mixture in a liquid state and stirred at a low speed to ensure uniform coating or adsorption on the solid surface.

[0100] Next, the mixture containing the heptafluoropropane was placed in a sealed reaction vessel, and nitrogen gas was injected to form an inert atmosphere, thereby trapping the nitrogen gas inside or on the surface of the mixture. During this process, the nitrogen gas remained in the fire extinguishing agent composition.

[0101] For reference, based on 100 parts by weight of the silica aerogel, the fire extinguishing agent contained 30 parts by weight, and a fire extinguishing composition was prepared using this.

[0102] <Comparative Example 1>

[0103] In Example 1 above, a fire extinguishing composition was prepared using only a fire extinguishing agent without including silica aerogel.

[0104] <Comparative Example 2>

[0105] In the above Example 1, a dense silica aerogel was used, having a porosity of 60% or less and an average pore diameter of 10 nm or less, and was prepared in the same manner as in Example 1.

[0106] <Comparative Example 3>

[0107] In the above Example 1, the above example was prepared in the same manner as Example 1, except that silica aerogel with an average particle size of 100 μm or more was used.

[0108] <Comparative Example 4>

[0109] The silica aerogel of Example 1 was used, but the fire extinguishing agent was loaded via a chemical bonding method rather than by physically adsorbing it into the pores of the silica aerogel, and the product was prepared in the same manner as Example 1. Specifically, the silica aerogel was treated such that functional groups were introduced to its surface by a silane coupling agent, and then a phosphorus-based flame retardant formed a covalent bond with said functional groups.

[0110] After surface modification of silica aerogel powder by immersing it in a silane coupling agent solution containing amino or epoxy groups, the modified silica aerogel was reacted with a phosphorus-based flame retardant to immobilize the fire extinguishing agent through chemical bonding.

[0111] <Experimental Example>

[0112] <Experimental Example 1> Evaluation of Initial Fire Suppression Performance by Application of Wire Terminal Caps

[0113] After applying each fire extinguishing composition prepared in Example 1 and Comparative Examples 1 to 4 to a wire terminal cap, the initial fire suppression performance in an electrical distribution panel environment was evaluated. Specifically, each fire extinguishing composition was filled in equal weights inside a wire terminal cap molded from a polyamide (PA)-based insulating resin, and then the terminal cap was fastened to the end of a copper wire of 6 mm² to form a test wire assembly.

[0114] After mounting the above wire assembly inside a simulated electrical distribution panel, an overcurrent exceeding the rated current was applied to induce arcing and localized heating at the wire end. At this time, the initial fire suppression characteristics were evaluated by observing the temperature change at the wire end, whether flames occurred, the time of smoke generation, and the duration of the flames, and the results are listed in Table 1 below.

[0115] Average flame occurrence time (seconds) Flame duration (seconds) Maximum temperature reached (°C) Level of smoke generation Example 1 2.1 3.5 165 Very low Comparative Example 1 2.0 18.7 310 Very high Comparative Example 2 2.2 12.4 265 height Comparative Example 3 2.1 9.6 240 middle Comparative Example 4 2.0 15.3 290 height

[0116] As shown in Table 1, the wire terminal cap to which the fire extinguishing composition of Example 1 was applied showed the shortest average flame duration after flame generation, at approximately 3.5 seconds, and the maximum temperature reached was also suppressed to 165°C, confirming that the initial fire was rapidly extinguished. This is believed to be the result of the fire extinguishing agent, which is physically adsorbed into the porous structure of the silica aerogel, being immediately released upon a temperature rise caused by the fire, thereby allowing oxygen dilution, cooling, and flame retardant effects to work together.

[0117] On the other hand, Comparative Example 1 did not contain silica aerogel, so the extinguishing agent could not be maintained locally, and the flame duration increased significantly to 18 seconds or more. In addition, Comparative Examples 2 and 3 contained silica aerogel, but as the pore structure or particle size fell outside the scope of the present invention, the loading capacity and release efficiency of the extinguishing agent were reduced, and a significantly longer flame duration was observed compared to Example 1. In particular, Comparative Example 4 had the extinguishing agent immobilized by a chemical bonding method, so the immediate release of the extinguishing agent was limited despite the temperature rise, resulting in the lowest initial fire suppression performance.

[0118] From the above results, it was confirmed that when the fire extinguishing composition according to Example 1 of the present invention is applied to a wire terminal cap, it provides a spontaneous and rapid extinguishing effect against an initial fire occurring at the end of a wire in an electrical distribution panel.

[0119] Experimental Example 2: Evaluation of Long-term Reliability and Fire Extinguishing Agent Retention

[0120] This experiment is intended to evaluate whether the fire extinguishing agent of the fire extinguishing composition of the present invention remains stable and can exhibit initial fire suppression performance when necessary, even when applied inside a wire terminal cap for a long period. In particular, the purpose is to verify whether the fire extinguishing agent physically adsorbed into the porous pore structure of silica aerogel is not lost even after long-term environmental exposure.

[0121] Each fire extinguishing composition prepared in Example 1 and Comparative Examples 1 to 4 was filled into a wire terminal cap in equal weight, and then the wire terminal cap was fastened to the end of the wire. Afterward, each specimen was left in a high-temperature and high-humidity environment (temperature 60°C, relative humidity 90%) for 30 days to simulate the long-term usage environment inside an actual electrical distribution panel.

[0122] For each specimen stored under the above conditions, the retention rate of the extinguishing agent was evaluated by measuring the weight change of the extinguishing composition before and after storage. After storage was completed, the initial fire suppression performance was re-evaluated by applying an overcurrent in the same manner as in Experimental Example 1, and the results are listed in Table 2. (Temperature 60℃ / Relative humidity 90% / After 30 days of storage)

[0123] Maintenance rate (%) relative to the weight of the initial digested composition Weight reduction rate (%) Flame duration (seconds) Maximum temperature reached (°C) Digestion performance evaluation Example 1 96.2 3.8 3.9 170 Very excellent Comparative Example 1 71.5 28.5 21.4 325 error Comparative Example 2 83.1 16.9 13.8 280 Insufficient Comparative Example 3 86.4 13.6 10.9 255 commonly Comparative Example 4 94.8 5.2 16.1 295 Insufficient

[0124] As shown in Table 2, the fire extinguishing composition of Example 1 maintained a weight retention rate of approximately 96% or higher even after exposure to a high temperature and high humidity environment for 30 days, and the flame duration was also within approximately 4 seconds, confirming that the initial fire suppression performance was stably maintained. This is because the fire extinguishing agent physically adsorbed into the porous pore structure of the silica aerogel forms a structure that is not easily lost due to the external environment, yet can be released immediately upon the occurrence of a fire.

[0125] In contrast, Comparative Example 1 lacked a supporting structure, resulting in a significant increase in the weight loss rate of the extinguishing agent after long-term exposure to over 28%, and a remarkably longer flame duration in the event of a fire. Additionally, although Comparative Examples 2 and 3 contained silica aerogel, the pore structure or particle size fell outside the scope of the present invention, leading to a tendency for both the retention rate and discharge efficiency of the extinguishing agent to decrease simultaneously. Comparative Example 4 maintained the extinguishing agent relatively stably through a chemical bonding method, but showed a result of reduced extinguishing performance due to limited immediate discharge in the event of a fire.

[0126] As described above, although the present invention has been explained with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

Claim 1 A fire extinguishing composition for a wire cap or busbar tube applied to the end of a wire in an electrical distribution board, wherein the fire extinguishing composition comprises a silica aerogel and a fire extinguishing agent physically supported in the pores of the silica aerogel, wherein the silica aerogel has an average particle size of 10 μm or more and 50 μm or less, a porosity of 85% or more and 90% or less, and an average pore diameter of 50 nm or more and 100 nm or less. Claim 2 A fire extinguishing composition according to claim 1, wherein the fire extinguishing agent is supported on a silica aerogel and is a non-conductive fire extinguishing agent that is released by heat. Claim 3 A fire extinguishing composition according to claim 2, wherein the fire extinguishing agent is released as the pore structure of the silica aerogel collapses due to a temperature rise caused by a fire. Claim 4 The extinguishing agent of claim 1 is a non-conductive extinguishing agent having electrical insulation properties, and is a extinguishing composition comprising at least one selected from an inert gas, a halogenated hydrocarbon-based extinguishing agent, a bicarbonate-based extinguishing agent, a phosphorus-based flame retardant, and a nitrogen-based flame retardant. Claim 5 A fire extinguishing composition according to claim 1, wherein the fire extinguishing agent comprises at least 1 part by weight and no more than 40 parts by weight based on 100 parts by weight of the silica aerogel. Claim 6 A extinguishing composition according to claim 1, characterized in that the extinguishing composition further comprises a binder or a dispersant to improve the dispersion stability of the silica aerogel. Claim 7 A method for preparing a fire extinguishing composition comprising: a step of preparing silica aerogel powder; and a step of mixing and loading a fire extinguishing agent onto the silica aerogel powder; wherein the loading step is a physical adsorption-based loading by stirring at a temperature of 10°C or higher and 30°C or lower, at a speed of 300 rpm or higher and 800 rpm or lower, and for 30 minutes to 1 hour; wherein the step of preparing the silica aerogel powder comprises: a step of preparing a water glass emulsion solution by mixing and stirring water glass, a surfactant, and an organic solvent; a step of forming a silica wet gel by adding and stirring acetic acid and isopropanol to the emulsion solution; and a step of separating and recovering the silica wet gel to form spherical silica aerogel powder; wherein the formed silica aerogel powder has an average particle size of 10 μm or higher and 50 μm or lower, a porosity of 85% or higher and 90% or lower, and an average pore diameter of 50 nm or higher and 100 nm or lower. Claim 8 delete Claim 9 A method for preparing a extinguishing composition according to claim 7, wherein in the step of preparing the water glass emulsion solution, the stirring rpm is 5,000 rpm or more and 8,000 rpm or less, and the stirring time is 5 minutes or more and 15 minutes or less. Claim 10 delete Claim 11 A method for preparing a extinguishing composition according to claim 7, wherein the step of separating and recovering the silica wet gel to form spherical silica aerogel powder comprises: the step of separating and recovering the silica wet gel; and the step of washing and drying the recovered wet gel.

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