Phenolic melt-blown cloth applied to tunnel fire prevention and preparation method of phenolic melt-blown cloth

Abstract

The invention relates to the technical field of polymer composite materials, in particular to a phenolic melt-blown fabric applied to tunnel fire prevention and a preparation method of the phenolic melt-blown fabric. 5-18 parts of a space-time adaptive heterogeneous flame retardant topological agent; 10 to 25 parts of dynamic self-adaptive strain energy storage ceramic microspheres; 10 to 20 parts of ammonium polyphosphate; 5 to 10 parts of melamine cyanurate; 3-8 parts of a modified triazine charring agent; 1 to 3 parts of plasma modified two-dimensional transition metal sulfide nanosheets; 0.5 to 2 parts of fluoroalkyl silane modifier steam; 2 to 6 parts of a microencapsulated silicate ester self-repairing agent; 50 to 100 parts of deionized water; 1 to 5 parts of sodium carboxymethyl cellulose; and 1 to 5 parts of sodium polyacrylate. Intelligent flame retardance is realized through phase change and network reconstruction of the space-time adaptive heterogeneous flame retardant topological agent at high temperature, so that the material has excellent adaptive fire resistance, high mechanical strength, damage self-repairing and super-hydrophobic characteristics.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, specifically to a phenolic meltblown fabric for tunnel fireproofing and its preparation method. Background Technology

[0002] Phenolic meltblown fabric, as a special polymer fire-resistant material, is widely used in tunnel fire protection to prevent the spread of fire and protect structural safety due to its unique chemical stability and excellent thermal insulation properties. The enclosed space inside tunnels experiences a rapid temperature increase during a fire, requiring fire-resistant materials to possess extremely high heat resistance, low smoke and non-toxic properties, as well as good flexibility and adhesion. Specific technical requirements include the ability to quickly form fire barriers, withstand prolonged high-temperature impacts, reduce the release of toxic gases, and adapt to the harsh, humid, and dusty environment inside tunnels.

[0003] In response to the above needs, the industry has proposed the following targeted technical solutions:

[0004] High-temperature melt extrusion method: Using phenolic resin as the base material, a microfiber structure is formed through a high-temperature molten extrusion process. This method enables continuous production of materials with uniform fiber diameter and stable fire resistance.

[0005] Chemical cross-linking enhancement method: A cross-linking agent is added during the melt-blowing process to form a three-dimensional network structure of phenolic molecules, thereby improving the mechanical strength and heat resistance of the material and making it less prone to deformation or cracking when exposed to fire.

[0006] Composite additive blending method: After blending nano flame retardants or inorganic fillers with phenolic resin, the mixture is melt-sprayed to enhance the flame retardant effect and durability of the material. This method can effectively improve the oxygen index and smoke density rating.

[0007] Although the above methods meet the basic requirements for tunnel fire prevention to a certain extent, they still have some shortcomings:

[0008] The production process is difficult to control: the high-temperature melting process is sensitive to temperature and time parameters, and slight deviations can easily lead to fiber breakage or uneven performance, affecting product consistency.

[0009] There are limitations in terms of material functionality: Phenolic meltblown fabric produced by existing methods may experience excessively rapid carbonization or premature detachment of the protective layer under extreme high temperatures, resulting in insufficient fire resistance durability.

[0010] Environmental and cost issues: Some chemical additives or processes involve hazardous substances, which not only increase production costs but may also pose environmental pollution risks, failing to meet the requirements of sustainable development. Summary of the Invention

[0011] To address the shortcomings of existing technologies, this invention provides a phenolic meltblown fabric for tunnel fireproofing and its preparation method, thus solving the problems mentioned above in the background technology.

[0012] According to a first aspect of the present invention, a phenolic meltblown nonwoven fabric for tunnel fireproofing is provided, comprising the following components in parts by weight:

[0013] Phenolic resin: 80-120 parts;

[0014] Spatiotemporally adaptive heterogeneous flame retardant topology agent: 5-18 parts;

[0015] Dynamic adaptive strain energy storage ceramic microspheres: 10-25 parts;

[0016] Ammonium polyphosphate: 10-20 parts;

[0017] Melamine cyanurate: 5-10 parts;

[0018] Modified triazine charring agent: 3-8 parts;

[0019] Plasma-modified two-dimensional transition metal sulfide nanosheets: 1-3 parts;

[0020] Fluorosilane modifier vapor: 0.5–2 parts;

[0021] Microencapsulated silicate self-healing agent: 2-6 parts;

[0022] Deionized water: 50-100 parts;

[0023] Sodium carboxymethyl cellulose: 1-5 parts;

[0024] Sodium polyacrylate: 1 to 5 parts.

[0025] Phenolic resin, as a basic fire-resistant substrate, can form a dense char layer at high temperatures, which can effectively block oxygen and heat, thereby slowing the spread of fire.

[0026] Ammonium polyphosphate is used to promote carbonization and form a protective layer. Ammonium polyphosphate decomposes at high temperatures to produce phosphoric acid, which promotes the dehydration and carbonization of the substrate, forming a porous carbon layer that isolates oxygen and heat.

[0027] Plasma-modified two-dimensional transition metal sulfide nanosheets are used to improve the thermal conductivity and thermal stability of materials. The plasma-modified two-dimensional transition metal sulfide nanosheets can effectively disperse heat, improve the thermal conductivity of materials, and enhance structural stability.

[0028] Deionized water is used to adjust the viscosity and processing properties of materials. As a solvent, deionized water can evenly disperse other components, giving the material good processing properties without affecting its fire resistance.

[0029] According to an embodiment of the present invention, the spatiotemporally adaptive heterogeneous flame-retardant topology agent is a heterogeneous composite particle formed by loading vanadium pentoxide nano-islands onto a hexagonal boron nitride substrate via chemical vapor deposition; the dynamic adaptive strain energy storage ceramic microspheres are core-shell structured microspheres with a particle size of 5-50 μm, prepared by emulsion polymerization and phase separation technology from polysiloxane hybrid resin, hydroxyl-terminated polybutadiene, and nano-hydroxyapatite in a mass ratio of 100:20:5-100:40:15; and the melamine cyanurate is a white, uniform powder synthesized by reacting melamine and cyanuric acid at 155-165°C.

[0030] The phase transition temperature of the vanadium pentoxide nanoisland is 330-350℃, and the mass ratio of the vanadium pentoxide nanoisland to the hexagonal boron nitride is 1:5-1:15.

[0031] The polysiloxane hybrid resin is a hybrid particle generated by reacting linear phenolic resin, aminophenylboronic acid and aminopropyltriethoxysilane in a mass ratio of 100:10:5-110:10:5.

[0032] The nano-hydroxyapatite is a nanoparticle synthesized from calcium hydroxide and phosphoric acid in a mass ratio of 1.25:1-1.35:1 under hydrothermal conditions at 160-180℃.

[0033] The mass ratio of melamine to cyanuric acid is 1:0.8 to 1:1.2.

[0034] Spatiotemporally adaptive heterogeneous flame-retardant topologies are used to provide dynamic and intelligent flame-retardant protection in fires. The unique heterogeneous structure of these topologies induces phase transitions and topological reconstruction at high temperatures. The vanadium pentoxide nanoislands absorb a large amount of heat during the phase transition, while their crystal structure transformation synergistically with the hexagonal boron nitride substrate, resulting in in-situ reconstruction of a dense, continuous heterogeneous barrier network. This network not only physically isolates oxygen and heat but also catalyzes the char formation reaction of substrates such as phenolic resins, significantly improving the quality and thermal stability of the char layer, achieving "spatiotemporally adaptive" optimization of flame-retardant performance.

[0035] Dynamically adaptive strain energy storage ceramic microspheres are used to enhance the structural integrity of materials. Their unique core-shell structure endows them with high elasticity and energy dissipation capabilities. Under the thermal expansion or mechanical stress caused by a fire, they store strain energy through shell deformation and dissipate energy through core-shell interface friction and nanoparticle slippage to buffer internal stress, preventing the fireproof layer from cracking and peeling, thus achieving "dynamically adaptive" mechanical protection.

[0036] Melamine cyanurate is used to improve the thermal stability of materials and reduce smoke production. When heated, melamine cyanurate decomposes to produce non-combustible gas, which dilutes the concentration of combustible gas. At the same time, the carbon layer formed can block heat.

[0037] According to embodiments of the present invention, a spatiotemporally adaptive heterogeneous flame-retardant topology agent, dynamically adaptive strain energy-storing ceramic microspheres, melamine cyanurate, and ammonium polyphosphate play a multi-level synergistic role in flame retardancy and structural protection within the fire protection system. The spatiotemporally adaptive heterogeneous flame-retardant topology agent undergoes a heterogeneous phase transformation and topological network reconstruction at temperatures above 330°C, forming a highly efficient thermal insulation barrier and catalyzing char formation. The dynamically adaptive strain energy-storing ceramic microspheres dissipate stress under thermal shock, maintaining the integrity of the char layer structure and preventing barrier rupture. Melamine cyanurate and ammonium polyphosphate work synergistically in the gas and condensed phases, diluting combustible gases and promoting the formation of an expanded char layer. These four components work synergistically across multiple dimensions—time, space, gas phase, and condensed phase—to construct an adaptive, highly stable three-dimensional fire protection system, significantly extending fire resistance time and suppressing smoke generation.

[0038] According to an embodiment of the present invention, the modified triazine charring agent is a core-shell structured powder obtained by ball milling and coating a triazine charring agent and a silane coupling agent; the microencapsulated silicate self-healing agent is a white microsphere particle prepared by in-situ polymerization of urea-formaldehyde resin as the wall material and silicate as the core material; the fluorosilane modifier vapor is a colorless and transparent vapor generated by the vaporization of heptadecafluorodecyltrimethoxysilane at 80-100°C.

[0039] The mass ratio of the triazine char-forming agent to the silane coupling agent is 10:1-20:1.

[0040] The mass ratio of the urea-formaldehyde resin to the silicate ester is 1:3-1:5.

[0041] Modified triazine charring agents are used to enhance the charring effect and improve fire resistance. Modified triazine charring agents can quickly form a stable char layer at high temperatures, effectively isolating oxygen and heat and extending the fire resistance time.

[0042] Fluorosilane modifier vapors are used to improve the hydrophobicity and durability of materials. Fluorosilane modifier vapors can form a hydrophobic layer on the material surface, preventing moisture intrusion and improving the stability of the material in humid environments.

[0043] Microencapsulated silicate self-healing agents are used to achieve the self-healing function of materials. When materials are damaged, microencapsulated silicate self-healing agents can release silicates, fill cracks, restore the integrity of materials, and extend their service life.

[0044] According to embodiments of the present invention, the modified triazine charring agent rapidly generates a stable char layer at high temperatures through a core-shell structure, effectively blocking heat transfer. Fluorosilane modifier vapor constructs a durable hydrophobic interface on the material surface, resisting the penetration of environmental moisture. Microencapsulated silicate self-healing agents automatically release repair substances when the char layer is damaged, restoring structural continuity. These three agents, in synergy with a spatiotemporally adaptive heterogeneous flame-retardant topology agent, further enhance the density, environmental durability, and self-healing ability of the char layer based on the topological network framework, giving the fire protection system comprehensive, multi-layered protective characteristics.

[0045] According to an embodiment of the present invention, the sodium carboxymethyl cellulose is a white fibrous powder with a viscosity of 800-1200 mPa·s generated from cotton fibers through alkalization and etherification reactions; the sodium polyacrylate is a white flake-like solid with a weight average molecular weight of 3000-5000 polymerized from sodium acrylate and deionized water.

[0046] The mass ratio of sodium acrylate to deionized water is 1:4 to 1:6.

[0047] Sodium carboxymethyl cellulose is used to increase the adhesion and flexibility of materials. Sodium carboxymethyl cellulose can improve the viscosity and adhesion of materials, making fireproof materials easier to apply, while also enhancing their flexibility.

[0048] Sodium polyacrylate is used to regulate the water absorption and swelling properties of materials. Sodium polyacrylate can absorb moisture and expand to form a protective layer, thereby improving the flame retardant properties and structural stability of the material.

[0049] According to embodiments of the present invention, sodium carboxymethyl cellulose optimizes the adhesion properties and flexibility of the material, ensuring uniform adhesion and good formability during construction. Sodium polyacrylate forms a dense protective layer through water absorption and swelling behavior, enhancing structural integrity and flame retardant performance. The synergistic effect of these two components ensures the stable existence of a homogeneous slurry containing solid functional particles such as a spatiotemporally adaptive heterogeneous flame retardant topology agent, and in subsequent impregnation and freeze-drying processes, the auxiliary functional particles are uniformly distributed and orderly assembled in the phenolic fiber felt network.

[0050] According to a second aspect of the present invention, a method for preparing the above-mentioned phenolic meltblown nonwoven fabric for tunnel fireproofing is provided, such as... Figure 1 As shown, it includes the following steps:

[0051] S1: After melting the phenolic resin, phenolic resin-based porous fiber felt is prepared by electrospinning and melt-blowing composite process.

[0052] S2: Prepare the plasma-modified two-dimensional transition metal sulfide nanosheets;

[0053] S3: The spatiotemporally adaptive heterogeneous flame retardant topology agent, dynamically adaptive strain energy storage ceramic microspheres, ammonium polyphosphate, melamine cyanurate, modified triazine charring agent and plasma-modified two-dimensional transition metal sulfide nanosheets are dry-mixed and then ball-milled to obtain composite flame retardant powder.

[0054] S4: Add the composite flame retardant powder and the microencapsulated silicate self-healing agent to the deionized water, then add the sodium carboxymethyl cellulose and the sodium polyacrylate, and emulsify at high speed to form a uniform slurry;

[0055] S5: The phenolic resin-based porous fiber felt is impregnated in the uniform slurry, and then subjected to vacuum-assisted impregnation, directional freezing and freeze-drying. The uniform slurry is assembled in situ in the phenolic resin-based porous fiber felt to form a biomimetic layered green body with a vertically oriented pore structure.

[0056] S6: The biomimetic layered green body is placed in a closed reactor, and the fluorosilane modifier vapor is introduced for vapor phase deposition to prepare a superhydrophobic modified green body;

[0057] S7: First, the superhydrophobic modified green body is pre-cured using ultraviolet light, and then hot air curing is performed to obtain the phenolic meltblown fabric.

[0058] According to an embodiment of the present invention, the step of preparing phenolic resin-based porous fiber mat by electrospinning and meltblowing composite process after melting the phenolic resin includes:

[0059] The phenolic resin is melt-plasticized in a screw extruder at 180-220℃, and the melt flow rate is controlled at 25-35g / 10min to obtain phenolic resin melt.

[0060] The phenolic resin melt is conveyed to a composite nozzle and spun under the conditions of electrospinning voltage of 15-25kV, receiving distance of 15-25cm, and melt jet velocity of 8000-12000m / min to obtain the phenolic resin-based porous fiber felt.

[0061] According to embodiments of the present invention, melt plasticizing provides a uniform and stable melt state for the phenolic resin. Electrospinning stretches the melt into ultrafine fibers using an electric field. Meltblowing utilizes airflow to promote rapid dispersion and web formation of the fibers. These three processes work synergistically to form a high-porosity, uniformly structured fiber felt network, significantly improving thermal barrier efficiency and mechanical strength, providing excellent thermal insulation performance and structural stability for tunnel fireproof materials.

[0062] According to an embodiment of the present invention, the preparation of the plasma-modified two-dimensional transition metal sulfide nanosheets includes:

[0063] Molybdenum disulfide was placed in deionized water and peeled off for 60-90 minutes in an ice-water bath using an ultrasonic cell disruptor with a power of 800-1200W to obtain a primary dispersion, wherein the mass ratio of molybdenum disulfide to deionized water was 1:100-1:150.

[0064] The primary dispersion was centrifuged at 1000-2000 rpm for 10 minutes to remove the thick precipitate, and then centrifuged at 8000-10000 rpm for 30 minutes to collect the supernatant to obtain the purified dispersion.

[0065] After the purified dispersion is vacuum filtered to form a film, it is placed in a plasma treatment device under an argon atmosphere and treated for 5-15 minutes under the conditions of 50-100W power and 30-50Pa pressure to obtain the plasma-modified two-dimensional transition metal sulfide nanosheets.

[0066] According to embodiments of the present invention, ultrasonic exfoliation achieves uniform dissociation of molybdenum disulfide under low-temperature conditions. Centrifugal purification removes impurities and improves the purity of the dispersion through precise stepwise processing. Vacuum filtration forms a continuous and dense thin film substrate. Plasma treatment optimizes surface chemical properties in an inert atmosphere. These four processes work synergistically to ensure that the nanosheets possess high uniformity, high purity, and surface activity, significantly enhancing their thermal conductivity and structural stability in fire-resistant systems, and providing the material with excellent thermal management capabilities.

[0067] According to an embodiment of the present invention, the step of impregnating the phenolic resin-based porous fiber felt in the uniform slurry, and then subjecting it to vacuum-assisted impregnation, directional freezing, and freeze-drying, wherein the uniform slurry is assembled in situ within the phenolic resin-based porous fiber felt to form a biomimetic layered green body with a vertically oriented pore structure, comprises:

[0068] The phenolic resin-based porous fiber felt is immersed in the uniform slurry and placed in a vacuum impregnation device. The pressure is controlled at -0.08 to -0.095 MPa and maintained for 10-30 minutes. Then, the pressure is restored to normal to obtain slurry-saturated fiber felt.

[0069] The saturated fiber felt is placed on a directional freezing stage at -20 to -25°C, and the cold source is controlled to conduct unidirectionally from bottom to top. The temperature is reduced to -30 to -50°C at a rate of 1-5°C / min to obtain a frozen fiber felt with vertical ice crystals.

[0070] The frozen fiber felt is placed in a freeze dryer and dried for 24-48 hours under conditions of cold trap temperature of -50 to -80°C and vacuum degree of 1-10 Pa to obtain the biomimetic layered green body.

[0071] According to embodiments of the present invention, the three-step process of vacuum-assisted impregnation, directional freezing, and freeze-drying works synergistically to construct a biomimetic layered structure. Vacuum-assisted impregnation ensures that the uniform slurry containing functional particles such as spatiotemporally adaptive heterogeneous flame-retardant topology agents and dynamically adaptive strain energy storage ceramic microspheres fully penetrates the pores inside the slurry-saturated fiber felt. Directional freezing guides the vertical growth of ice crystals through a unidirectional cold source, forcing the functional particles to arrange themselves orderly in the gaps between the ice crystals. Freeze-drying, through the sublimation of ice crystals, forms vertically oriented channels in situ and firmly attaches the functional particles to the channel walls. This structure, mimicking the layered ducts of wood, not only significantly improves the overall thermal insulation performance of the material but also provides an ideal spatial topological basis for the spatiotemporally adaptive heterogeneous flame-retardant topology agent to construct a continuous and orderly barrier network in a fire.

[0072] According to an embodiment of the present invention, the pressure of the vapor deposition is -0.08 to -0.05 MPa, the temperature is 80-100°C, and the time is 30-60 minutes.

[0073] According to an embodiment of the present invention, the step of first pre-curing the superhydrophobic modified green body with ultraviolet light, followed by hot air curing, to obtain the phenolic meltblown fabric comprises:

[0074] The superhydrophobic modified green body was irradiated for 3-5 minutes using an ultraviolet light source with a wavelength of 365-385nm and a light intensity of 50-100mW / cm² to obtain the initial crosslinked material.

[0075] The initial cross-linked material is placed in a hot air drying oven and cured with circulating hot air at 130-150℃ for 8-12 minutes with the wind speed controlled at 5-10m / s. The spatiotemporal adaptive heterogeneous flame retardant topology agent undergoes heterogeneous transformation and topological network reconstruction to obtain the phenolic meltblown fabric.

[0076] According to embodiments of the present invention, the two-step curing process of ultraviolet light pre-curing and hot air curing works synergistically to achieve gradient cross-linking and performance stabilization of the material. Ultraviolet light pre-curing rapidly initiates the cross-linking reaction on the surface of the phenolic resin, forming a preliminary stable framework that fixes the structure of the biomimetic layered green body and its superhydrophobic surface. Subsequent hot air curing, at a higher temperature, performs deep cross-linking, not only completely curing the phenolic resin matrix to achieve optimal mechanical strength but also providing the necessary thermal environment for the vanadium pentoxide nano-islands in the spatiotemporally adaptive heterogeneous flame-retardant topology agent, further stabilizing its heterogeneous structure and preparing it for the "adaptive" flame-retardant function.

[0077] The present invention has the following beneficial effects:

[0078] This invention introduces two core components: a spatiotemporally adaptive heterogeneous flame-retardant topology agent and dynamically adaptive strain energy-storing ceramic microspheres. It employs vacuum impregnation and directional freeze-drying processes to construct a biomimetic vertical pore structure, achieving intelligent upgrades and structural optimization of fire resistance. The spatiotemporally adaptive heterogeneous flame-retardant topology agent reconstructs at specific high temperatures, forming a dynamically strengthened thermal insulation barrier. The dynamically adaptive strain energy-storing ceramic microspheres effectively buffer thermal stress, maintaining the barrier's integrity. The two components work synergistically within the biomimetic pore structure, achieving a leap in flame retardancy from static to dynamic, and from homogeneous to ordered.

[0079] This invention utilizes plasma-modified two-dimensional transition metal sulfide nanosheets to optimize the heat conduction path, ensuring uniform heat distribution. A vapor deposition process constructs a durable hydrophobic layer on the surface, effectively resisting erosion from the humid environment inside the tunnel, maintaining long-term stability of fire resistance, and preventing performance degradation due to environmental factors.

[0080] This invention innovatively introduces a microencapsulated silicate self-healing agent, enabling dynamic repair of the material after damage. Fluorosilane modifier vapor forms a molecular-level hydrophobic barrier on the surface, preventing moisture penetration and ensuring the integrity of the char layer. The synergistic effect of these two components allows the fire protection system to maintain structural continuity during a fire, avoiding localized failures, significantly extending effective protection time, and reducing maintenance frequency and costs.

[0081] This invention utilizes environmentally friendly natural ingredients and green manufacturing processes to minimize negative environmental impacts. The spatiotemporally adaptive heterogeneous flame-retardant topology agent and microencapsulated silicate self-healing agent are derived from sustainable resources, and the manufacturing process avoids harmful substances. The product meets safety and environmental standards, is non-toxic and harmless, and ensures that it will not release harmful gases when used in enclosed spaces such as tunnels, meeting the stringent health and safety requirements of modern engineering.

[0082] The phenolic meltblown fabric prepared by this invention has excellent workability and wide applicability. Its internal vertical pore structure and superhydrophobic surface treatment give it excellent fire resistance as well as good flexibility, adhesion and moisture resistance, making it very suitable for fire protection needs in complex and harsh environments such as tunnels and underground engineering projects.

[0083] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0084] Figure 1 This is a flowchart of the preparation method according to an embodiment of the present invention. Detailed Implementation

[0085] This application provides an embodiment of a phenolic meltblown fabric for tunnel fire prevention and its preparation method.

[0086] Example 1: Standard Formulation Phenolic Meltblown Fabric

[0087] Phenolic resin: 100 parts;

[0088] Spatiotemporally adaptive heterogeneous flame retardant topology agent: 12 parts;

[0089] Dynamic adaptive strain energy storage ceramic microspheres: 18 parts;

[0090] Ammonium polyphosphate: 15 parts;

[0091] Melamine cyanurate: 8 parts;

[0092] Modified triazine charring agent: 5 parts;

[0093] Plasma-modified two-dimensional transition metal sulfide nanosheets: 2 parts;

[0094] Fluorosilane modifier vapor: 1 part;

[0095] Microencapsulated silicate self-healing agent: 4 parts;

[0096] Deionized water: 75 parts;

[0097] Sodium carboxymethyl cellulose: 3 parts;

[0098] Sodium polyacrylate: 3 parts.

[0099] Example 2: Increasing the content of spatiotemporally adaptive heterogeneous flame retardant topology agent

[0100] Phenolic resin: 100 parts;

[0101] Spatiotemporally adaptive heterogeneous flame retardant topology agent: 18 parts;

[0102] Dynamic adaptive strain energy storage ceramic microspheres: 18 parts;

[0103] Ammonium polyphosphate: 15 parts;

[0104] Melamine cyanurate: 8 parts;

[0105] Modified triazine charring agent: 8 parts;

[0106] Plasma-modified two-dimensional transition metal sulfide nanosheets: 2 parts;

[0107] Fluorosilane modifier vapor: 1 part;

[0108] Microencapsulated silicate self-healing agent: 4 parts;

[0109] Deionized water: 75 parts;

[0110] Sodium carboxymethyl cellulose: 3 parts;

[0111] Sodium polyacrylate: 3 parts.

[0112] Example 3: Increasing the content of dynamic adaptive strain energy storage ceramic microspheres

[0113] Phenolic resin: 100 parts;

[0114] Spatiotemporally adaptive heterogeneous flame retardant topology agent: 12 parts;

[0115] Dynamic adaptive strain energy storage ceramic microspheres: 25 parts;

[0116] Ammonium polyphosphate: 15 parts;

[0117] Melamine cyanurate: 8 parts;

[0118] Modified triazine charring agent: 5 parts;

[0119] Plasma-modified two-dimensional transition metal sulfide nanosheets: 1 part;

[0120] Fluorosilane modifier vapor: 1 part;

[0121] Microencapsulated silicate self-healing agent: 4 parts;

[0122] Deionized water: 75 parts;

[0123] Sodium carboxymethyl cellulose: 3 parts;

[0124] Sodium polyacrylate: 3 parts.

[0125] Example 4: Enhanced fire resistance

[0126] Phenolic resin: 100 parts;

[0127] Spatiotemporally adaptive heterogeneous flame retardant topology agent: 12 parts;

[0128] Dynamic adaptive strain energy storage ceramic microspheres: 18 parts;

[0129] Ammonium polyphosphate: 20 parts;

[0130] Melamine cyanurate: 8 parts;

[0131] Modified triazine charring agent: 5 parts;

[0132] Plasma-modified two-dimensional transition metal sulfide nanosheets: 2 parts;

[0133] Fluorosilane modifier vapor: 1 part;

[0134] Microencapsulated silicate self-healing agent: 4 parts;

[0135] Deionized water: 75 parts;

[0136] Sodium carboxymethyl cellulose: 3 parts;

[0137] Sodium polyacrylate: 3 parts.

[0138] Example 5: Optimizing fire resistance time

[0139] Phenolic resin: 100 parts;

[0140] Spatiotemporally adaptive heterogeneous flame retardant topology agent: 15 parts;

[0141] Dynamic adaptive strain energy storage ceramic microspheres: 18 parts;

[0142] Ammonium polyphosphate: 15 parts;

[0143] Melamine cyanurate: 8 parts;

[0144] Modified triazine charring agent: 5 parts;

[0145] Plasma-modified two-dimensional transition metal sulfide nanosheets: 2 parts;

[0146] Fluorosilane modifier vapor: 1 part;

[0147] Microencapsulated silicate self-healing agent: 4 parts;

[0148] Deionized water: 75 parts;

[0149] Sodium carboxymethyl cellulose: 3 parts;

[0150] Sodium polyacrylate: 3 parts.

[0151] Example 6: Improving Mechanical Strength

[0152] Phenolic resin: 100 parts;

[0153] Spatiotemporally adaptive heterogeneous flame retardant topology agent: 12 parts;

[0154] Dynamic adaptive strain energy storage ceramic microspheres: 22 parts;

[0155] Ammonium polyphosphate: 15 parts;

[0156] Melamine cyanurate: 8 parts;

[0157] Modified triazine charring agent: 5 parts;

[0158] Plasma-modified two-dimensional transition metal sulfide nanosheets: 2 parts;

[0159] Fluorosilane modifier vapor: 1 part;

[0160] Microencapsulated silicate self-healing agent: 6 parts;

[0161] Deionized water: 75 parts;

[0162] Sodium carboxymethyl cellulose: 4 parts;

[0163] Sodium polyacrylate: 3 parts.

[0164] Comparative Example 1: Spatiotemporally Adaptive Heterogeneous Flame Retardant Topology Agent

[0165] Phenolic resin: 100 parts;

[0166] Dynamic adaptive strain energy storage ceramic microspheres: 18 parts;

[0167] Ammonium polyphosphate: 15 parts;

[0168] Melamine cyanurate: 8 parts;

[0169] Modified triazine charring agent: 5 parts;

[0170] Plasma-modified two-dimensional transition metal sulfide nanosheets: 2 parts;

[0171] Fluorosilane modifier vapor: 1 part;

[0172] Microencapsulated silicate self-healing agent: 4 parts;

[0173] Deionized water: 75 parts;

[0174] Sodium carboxymethyl cellulose: 3 parts;

[0175] Sodium polyacrylate: 3 parts.

[0176] Comparative Example 2: Energy Storage Ceramic Microspheres Without Dynamic Adaptive Strain

[0177] Phenolic resin: 100 parts;

[0178] Spatiotemporally adaptive heterogeneous flame retardant topology agent: 12 parts;

[0179] Ammonium polyphosphate: 15 parts;

[0180] Melamine cyanurate: 8 parts;

[0181] Modified triazine charring agent: 5 parts;

[0182] Plasma-modified two-dimensional transition metal sulfide nanosheets: 2 parts;

[0183] Fluorosilane modifier vapor: 1 part;

[0184] Microencapsulated silicate self-healing agent: 4 parts;

[0185] Deionized water: 75 parts;

[0186] Sodium carboxymethyl cellulose: 3 parts;

[0187] Sodium polyacrylate: 3 parts.

[0188] Comparative Example 3: Microencapsulated silicate self-healing agent

[0189] Phenolic resin: 100 parts;

[0190] Spatiotemporally adaptive heterogeneous flame retardant topology agent: 12 parts;

[0191] Dynamic adaptive strain energy storage ceramic microspheres: 18 parts;

[0192] Ammonium polyphosphate: 15 parts;

[0193] Melamine cyanurate: 8 parts;

[0194] Modified triazine charring agent: 5 parts;

[0195] Plasma-modified two-dimensional transition metal sulfide nanosheets: 2 parts;

[0196] Fluorosilane modifier vapor: 1 part;

[0197] Deionized water: 75 parts;

[0198] Sodium carboxymethyl cellulose: 3 parts;

[0199] Sodium polyacrylate: 3 parts.

[0200] Comparative Example 4: Plasma-free modified two-dimensional transition metal sulfide nanosheets

[0201] Phenolic resin: 100 parts;

[0202] Spatiotemporally adaptive heterogeneous flame retardant topology agent: 12 parts;

[0203] Dynamic adaptive strain energy storage ceramic microspheres: 18 parts;

[0204] Ammonium polyphosphate: 15 parts;

[0205] Melamine cyanurate: 8 parts;

[0206] Modified triazine charring agent: 5 parts;

[0207] Fluorosilane modifier vapor: 1 part;

[0208] Microencapsulated silicate self-healing agent: 4 parts;

[0209] Deionized water: 75 parts;

[0210] Sodium carboxymethyl cellulose: 3 parts;

[0211] Sodium polyacrylate: 3 parts.

[0212] Experimental example:

[0213] The performance was measured based on Examples 1-6 and Comparative Examples 1-4 above, and the results are shown in Table 1. These include:

[0214] 1. Fire resistance performance test

[0215] The flame retardant properties of the material were evaluated by testing it under 50 kW / m² thermal radiation using a cone calorimeter and recording the peak heat release rate.

[0216] 2. Fire resistance time test

[0217] The sample was placed in a high-temperature environment of 500℃, and the time it took for the sample to remain intact was recorded to evaluate the fire resistance of the material.

[0218] 3. Mechanical strength test

[0219] The tensile strength was tested using a universal testing machine at a speed of 10 mm / min, and the maximum tensile force was recorded.

[0220] 4. Self-healing performance test

[0221] A 5mm crack was created on the sample surface, and the repair status of the crack was observed after 24 hours. The self-healing ability was represented by the repair rate.

[0222] 5. Adaptive flame retardant effect test

[0223] Thermogravimetric analysis and infrared spectroscopy were used to analyze the reduction rate of combustible hydrocarbon release from the samples in the 360℃ temperature range.

[0224] 6. Environmental performance testing

[0225] The VOC emissions of the materials were analyzed using gas chromatography-mass spectrometry, and the results met the GB / T 23451-2009 standard.

[0226] Table 1. Experimental data of Examples 1-6 and Comparative Examples 1-4 of the present invention

[0227] sample Peak heat release rate (kW / m²) Fire resistance time (min) Tensile strength (MPa) Repair rate (%) Hydrocarbon release reduction rate (%) VOC emissions (mg / m³) Example 1 135 68 26 85 65 30 Example 2 120 72 27 87 75 28 Example 3 140 66 30 80 62 32 Example 4 110 75 28 88 70 25 Example 5 128 74 27 86 72 29 Example 6 138 67 31 90 63 27 Comparative Example 1 185 55 22 75 18 35 Comparative Example 2 170 52 20 70 58 38 Comparative Example 3 160 58 23 65 62 33 Comparative Example 4 175 53 21 72 55 34

[0228] Table 1 shows the flame retardant and fire-resistant properties:

[0229] The peak heat release rate of all embodiments was significantly lower than that of the comparative example, and the fire resistance time was significantly longer. Embodiment 2 (increasing the content of spatiotemporally adaptive heterogeneous flame retardant topology agent) and Embodiment 4 (enhanced fire resistance performance) showed the best performance.

[0230] Comparative Example 1 (without spatiotemporally adaptive heterogeneous flame retardant topology agent) had the worst performance in these two aspects, proving that the spatiotemporally adaptive heterogeneous flame retardant topology agent is the core of improving flame retardant and fire resistance performance.

[0231] Enhanced adaptive performance:

[0232] The hydrocarbon release reduction rate of all embodiments was higher than 60%, while that of Comparative Example 1 was only 18%, which directly proves the core role of the spatiotemporally adaptive heterogeneous flame retardant topology agent in intelligently suppressing the release of combustible gases in key temperature ranges.

[0233] Improved mechanical and self-healing properties:

[0234] Examples 3 and 6 (containing high dynamic adaptive strain energy storage ceramic microspheres) exhibited the highest tensile strength. Example 6 also showed the highest repair rate.

[0235] Comparative Example 2 (without dynamic adaptive strain energy storage ceramic microspheres) had the weakest mechanical properties, while Comparative Example 3 (without microencapsulated silicate self-healing agent) had the worst self-healing ability, confirming the key functions of each of the two components.

[0236] Overall performance:

[0237] Examples 1-6 are superior to Comparative Examples 1-4 in all aspects of performance. The introduction of spatiotemporally adaptive heterogeneous flame-retardant topological agents and dynamically adaptive strain energy storage ceramic microspheres, in synergy with other components, significantly improves the material's intelligent flame retardancy, structural toughness, and damage self-healing properties, while also demonstrating good environmental performance (VOC emissions).

[0238] Based on the integrated experimental data described above, the phenolic meltblown fabric of this invention outperforms existing technologies in terms of fire resistance, fire resistance time, mechanical strength, self-healing properties, and environmental performance. This material is suitable for locations with high fire protection requirements, such as tunnels, subways, and large public buildings, and has broad application prospects and market potential. With the continuous expansion of tunnel construction and the increasing demands for fire safety, the phenolic meltblown fabric of this invention will become the preferred fireproofing material for tunnels and is expected to be widely used in building fire protection, rail transit, and mine safety, making a significant contribution to improving public safety.

[0239] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0240] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A phenolic meltblown nonwoven fabric for tunnel fireproofing, characterized in that, The phenolic meltblown fabric is composed of the following components in parts by weight: Phenolic resin: 80-120 parts; Spatiotemporally adaptive heterogeneous flame retardant topology agent: 5-18 parts; Dynamic adaptive strain energy storage ceramic microspheres: 10-25 parts; Ammonium polyphosphate: 10-20 parts; Melamine cyanurate: 5-10 parts; Modified triazine charring agent: 3-8 parts; Plasma-modified two-dimensional transition metal sulfide nanosheets: 1-3 parts; Fluorosilane modifier vapor: 0.5–2 parts; Microencapsulated silicate self-healing agent: 2-6 parts; Deionized water: 50-100 parts; Sodium carboxymethyl cellulose: 1-5 parts; Sodium polyacrylate: 1 to 5 parts.

2. The phenolic meltblown fabric according to claim 1, characterized in that: The spatiotemporally adaptive heterogeneous flame-retardant topology agent is a heterogeneous composite particle formed by loading vanadium pentoxide nano-islands with hexagonal boron nitride as a substrate through chemical vapor deposition; the dynamic adaptive strain energy storage ceramic microspheres are core-shell structured microspheres with a particle size of 5-50 μm, made by emulsion polymerization and phase separation technology of polysiloxane hybrid resin, hydroxyl-terminated polybutadiene, and nano-hydroxyapatite in a mass ratio of 100:20:5-100:40:15; the melamine cyanurate is a white uniform powder synthesized by reacting melamine and cyanuric acid at 155-165℃. The phase transition temperature of the vanadium pentoxide nanoisland is 330-350℃, and the mass ratio of the vanadium pentoxide nanoisland to the hexagonal boron nitride is 1:5-1:

15. The polysiloxane hybrid resin is a hybrid particle generated by reacting linear phenolic resin, aminophenylboronic acid and aminopropyltriethoxysilane in a mass ratio of 100:10:5-110:10:

5. The nano-hydroxyapatite is a nanoparticle synthesized from calcium hydroxide and phosphoric acid in a mass ratio of 1.25:1-1.35:1 under hydrothermal conditions at 160-180℃; the mass ratio of melamine to cyanuric acid is 1:0.8-1:1.

2.

3. The phenolic meltblown fabric according to claim 1, characterized in that: The modified triazine charring agent is a core-shell structured powder obtained by ball milling and coating a triazine charring agent with a silane coupling agent; the microencapsulated silicate self-healing agent is a white microsphere prepared by in-situ polymerization of urea-formaldehyde resin as the wall material and silicate as the core material; the fluorosilane modifier vapor is a colorless and transparent vapor generated by the vaporization of heptadecafluorodecyltrimethoxysilane at 80-100℃. The mass ratio of the triazine char-forming agent to the silane coupling agent is 10:1-20:

1. The mass ratio of the urea-formaldehyde resin to the silicate ester is 1:3-1:

5.

4. The phenolic meltblown fabric according to claim 1, characterized in that: The sodium carboxymethyl cellulose is a white fibrous powder with a viscosity of 800-1200 mPa·s produced by alkalization and etherification of cotton fibers; the sodium polyacrylate is a white flaky solid with a weight average molecular weight of 3000-5000, polymerized from sodium acrylate and deionized water. The mass ratio of sodium acrylate to deionized water is 1:4 to 1:

6.

5. A method for preparing phenolic meltblown fabric according to any one of claims 1-4, characterized in that: Includes the following steps: After melting the phenolic resin, phenolic resin-based porous fiber mat is prepared by electrospinning and meltblowing composite process. Preparation of the plasma-modified two-dimensional transition metal sulfide nanosheets; The spatiotemporally adaptive heterogeneous flame retardant topology agent, dynamically adaptive strain energy storage ceramic microspheres, ammonium polyphosphate, melamine cyanurate, modified triazine char-forming agent and plasma-modified two-dimensional transition metal sulfide nanosheets were dry-mixed and then ball-milled to obtain composite flame retardant powder. The composite flame retardant powder and the microencapsulated silicate self-healing agent are added to the deionized water, and then sodium carboxymethyl cellulose and sodium polyacrylate are added. The mixture is then emulsified by high-speed shearing to form a uniform slurry. The phenolic resin-based porous fiber felt is impregnated in the uniform slurry, and then subjected to vacuum-assisted impregnation, directional freezing and freeze-drying. The uniform slurry is assembled in situ within the phenolic resin-based porous fiber felt to form a biomimetic layered green body with a vertically oriented pore structure. The biomimetic layered green body is placed in a closed reactor, and the vapor of the fluorosilane modifier is introduced for vapor phase deposition to prepare a superhydrophobic modified green body. The superhydrophobic modified green fabric is first pre-cured using ultraviolet light, and then cured with hot air to obtain the phenolic meltblown fabric.

6. The preparation method according to claim 5, characterized in that: The process of preparing phenolic resin-based porous fiber mat by melting the phenolic resin and then using electrospinning and meltblowing composite processes includes: The phenolic resin is melt-plasticized in a screw extruder at 180-220℃, and the melt flow rate is controlled at 25-35g / 10min to obtain phenolic resin melt. The phenolic resin melt is conveyed to a composite nozzle and spun under the conditions of electrospinning voltage of 15-25kV, receiving distance of 15-25cm, and melt jet velocity of 8000-12000m / min to obtain the phenolic resin-based porous fiber felt.

7. The preparation method according to claim 5, characterized in that: The preparation of the plasma-modified two-dimensional transition metal sulfide nanosheets includes: Molybdenum disulfide was placed in deionized water and peeled off for 60-90 minutes in an ice-water bath using an ultrasonic cell disruptor with a power of 800-1200W to obtain a primary dispersion, wherein the mass ratio of molybdenum disulfide to deionized water was 1:100-1:

150. The primary dispersion was centrifuged at 1000-2000 rpm for 10 minutes to remove the thick precipitate, and then centrifuged at 8000-10000 rpm for 30 minutes to collect the supernatant to obtain the purified dispersion. After the purified dispersion is vacuum filtered to form a film, it is placed in a plasma treatment device under an argon atmosphere and treated for 5-15 minutes under the conditions of 50-100W power and 30-50Pa pressure to obtain the plasma-modified two-dimensional transition metal sulfide nanosheets.

8. The preparation method according to claim 5, characterized in that: The step of impregnating the phenolic resin-based porous fiber felt with the uniform slurry, followed by vacuum-assisted impregnation, directional freezing, and freeze-drying, wherein the uniform slurry is assembled in situ within the phenolic resin-based porous fiber felt to form a biomimetic layered green body with a vertically oriented pore structure, comprises: The phenolic resin-based porous fiber felt is immersed in the uniform slurry and placed in a vacuum impregnation device. The pressure is controlled at -0.08 to -0.095 MPa and maintained for 10-30 minutes. Then, the pressure is restored to normal to obtain slurry-saturated fiber felt. The saturated fiber felt is placed on a directional freezing stage at -20 to -25°C, and the cold source is controlled to conduct unidirectionally from bottom to top. The temperature is reduced to -30 to -50°C at a rate of 1-5°C / min to obtain a frozen fiber felt with vertical ice crystals. The frozen fiber felt is placed in a freeze dryer and dried for 24-48 hours under conditions of cold trap temperature of -50 to -80°C and vacuum degree of 1-10 Pa to obtain the biomimetic layered green body.

9. The preparation method according to claim 5, characterized in that: The vapor deposition was performed at a pressure of -0.08 to -0.05 MPa, a temperature of 80-100°C, and a time of 30-60 minutes.

10. The preparation method according to claim 5, characterized in that: The process involves first pre-curing the superhydrophobic modified green fabric with ultraviolet light, followed by hot air curing, to obtain the phenolic meltblown fabric, comprising: The superhydrophobic modified green body was irradiated for 3-5 minutes using an ultraviolet light source with a wavelength of 365-385nm and a light intensity of 50-100mW / cm² to obtain the initial crosslinked material. The initial cross-linked material is placed in a hot air drying oven and cured with circulating hot air at 130-150℃ for 8-12 minutes with the wind speed controlled at 5-10m / s. The spatiotemporal adaptive heterogeneous flame retardant topology agent undergoes heterogeneous transformation and topological network reconstruction to obtain the phenolic meltblown fabric.

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