Flexible fire-resistant and flame-retardant inorganic expansion composite fireproof material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of fire resistance and flame retardance, in particular to a flexible fire-resistant and flame-retardant inorganic expansion composite fireproof material and a preparation method and application thereof. The invention provides a flexible fire-resistant and flame-retardant inorganic expansion composite fireproof material. The flexible fire-resistant and flame-retardant inorganic expansion composite fireproof material comprises a silicon-based ceramic outer layer and an inorganic flexible expansion layer which are tightly attached, wherein the silicon-based ceramic outer layer comprises a high-temperature-resistant fiber base material and a silicon-based ceramic coating, the surface of the high-temperature-resistant fiber base material is coated with the silicon-based ceramic coating, the inorganic flexible expansion layer is an expansion sheet made through a slurry dehydration technology, and raw materials comprise sepiolite, brucite fibers, expanded graphite, an adhesive and a plasticizer. The composite fireproof material provided by the invention has a good fire-resistant function and a good flame-retardant function at the same time, is not easy to burn in a fire disaster, generates low smoke toxicity and extremely small smoke amount, can realize live-line construction, and brings great convenience to transformation of an existing project.

Description

Technical Field

[0001] The present invention relates to the technical field of fireproof and flame retardant, and particularly relates to a flexible fireproof, flame retardant inorganic expanded composite fireproof material, a preparation method thereof and an application thereof. Background Art

[0002] A cable is a device for transmitting electric energy or signals, usually composed of several or several groups of wires. Generally, there are two different requirements for cable fire protection. One is cable flame retardancy, that is, the cable itself does not participate or participates as little as possible in combustion under the action of fire or a fire source, and the influence on the expansion and spread of the fire is reduced as much as possible. The other is cable fire resistance, that is, under certain external fire conditions, the basic function of the cable to keep energized can still be maintained.

[0003] At present, cable flame retardancy is generally carried out by adding flame retardant materials to the cable outer skin or painting cable fireproof coatings, etc. Cable fire resistance is generally achieved by changing the cable structure, adding fireproof materials, etc., but there are still the following problems: 1. For cable flame retardancy, whether it is through cable outer skin flame retardancy or painting cable fireproof coatings, only the flame retardant function of the cable can be achieved, and for cable fire resistance, only the fire resistance function can be achieved. Therefore, at present, it is impossible to simultaneously achieve the flame retardant and fire resistance functions of the cable. 2. According to the current national standards, the detection cost of cable fireproof coating products or cable outer skin is relatively high, the detection cycle is relatively long, and it is difficult to screen unqualified products, resulting in unqualified products flooding the market; at the same time, due to the overly complex formula of material products, it is difficult to control product consistency. 3. As a key product for current cable flame retardancy, the cable fireproof coating has a great correlation between its flame retardant performance and construction quality, and due to external environmental factors such as humidity, ultraviolet radiation, and alternating hot and cold, problems such as cracking and peeling are likely to occur, and the actual use effect and the sustainability of the service life are extremely low. 4. Due to the low compatibility between coatings applied at different times or coatings with different formulas, it is very difficult to perform live operations without damaging the cable or replacing the cable in the case of engineering repairs for problems with the cable fireproof coating layer or when the cable fire protection level needs to be improved. 5. The current cable flame retardant and cable fire resistance solutions and materials, whether it is the cable's own material or structural design, or the application of cable fireproof coatings, the materials are not recyclable and cannot be recycled. 6. The current smoke toxicity and smoke production (smoke density) of existing materials or coatings are relatively large, and once a fire occurs, it is easy to cause the risk of suffocation for personnel. 7. When a fire occurs outside the cable's cladding, the existing products cannot achieve "non-destructive" protection of the internal cable for a certain period of time, and the post-disaster repair cost is relatively high; when a fire occurs inside the cladding, the existing products cannot achieve the internal "fire extinguishing" function either. Summary of the Invention

[0004] In view of this, the present invention provides a flexible fire-resistant, flame-retardant inorganic expanding composite fireproof material, its preparation method and application. This composite fireproof material has good fire-resistant and flame-retardant functions at the same time. It is not easy to burn in a fire, has a low toxicity of the generated smoke, extremely low smoke production, and can realize live construction, which is convenient to use.

[0005] To solve the above technical problems, the present invention provides a flexible fire-resistant, flame-retardant inorganic expanding composite fireproof material, which includes a closely attached silicon-based ceramized outer layer and an inorganic flexible expanding layer; wherein, the silicon-based ceramized outer layer includes a high-temperature resistant fiber substrate and a silicon-based ceramic coating coated on the surface of the high-temperature resistant fiber substrate; the inorganic flexible expanding layer is an expanded sheet made by a slurry dehydration process, and the raw materials include 40wt% - 60wt% of sepiolite, 5wt% -25wt% of brucite fiber, 10wt% - 30wt% of expanded graphite, 5wt% - 20wt% of binder, and 1wt% - 10wt% of plasticizer.

[0006] The composite fireproof material provided by the present invention has at least two-layer structure. Among them, the inorganic flexible expanding layer composed of specific components can produce physical-chemical synergistic changes at high fire temperatures, generating an expanded body with a large number of pores and excellent thermal stability. When this composite fireproof material is used as a coating to coat the surface of the object to be fireproofed, it can not only provide heat insulation protection for the object inside the coating such as cables under the condition of an external fire, but also realize the fire extinguishing function through the asphyxiation effect of the expanded body when a fire occurs inside the coating, achieving both flame-retardant and fire-resistant functions at the same time. The material selection of the inorganic flexible expanding layer provided by the present invention not only breaks through the current expanded graphite fireproof sealing material system based on organic carriers such as PVC, EVA, and ethylene propylene diene monomer rubber, but also avoids problems such as high smoke production and large smoke toxicity caused by the presence of a large number of organic carriers.

[0007] Regarding the material selection of the inorganic flexible expanding layer of the present invention: Sepiolite is a fibrous magnesium hydrosilicate with a unique layer-chain structure. Its fiber bundles can form a three-dimensional network skeleton, significantly improving the tensile strength and tear resistance of the material; at the same time, sepiolite also has channels with a through structure and active surfaces (such as Si-OH groups), which can adsorb resins or binders, enhance the interfacial bonding force between itself and the matrix, and reduce the internal defects of the material; sepiolite can maintain a stable structure below 400°C, and its internal channels can adsorb the gases generated by thermal decomposition at high temperatures, delaying combustion. Brucite fiber is a fibrous brucite, and the strength of a single fiber can reach 2 - 3 GPa. Its acicular columnar structure has the effect of dispersing stress and inhibiting crack propagation; the decomposition temperature of brucite fiber > 800°C, and it can still maintain a complete structure at high temperatures, and it does not contain asbestos and radioactive substances, so it can be used in relatively extreme environments.

[0008] The inorganic flexible expansion layer in the composite fireproof material provided by the present invention mainly uses sepiolite, brucite fiber and expandable graphite as raw materials. Among them, sepiolite and brucite fiber are cured through hydrogen bonds or intermolecular van der Waals forces to form a planar flexible material, endowing the inorganic flexible expansion layer with excellent comprehensive properties, and a synergistic effect can also be generated between the two. The main principle is as follows: The three-dimensional network is formed after the compounding of sepiolite (flexible fiber) and brucite (rigid fiber), which improves the overall tensile strength; the porous structure of sepiolite can also adsorb the binder, and cooperate with the brucite fiber providing the skeleton support to inhibit the deformation of the material; secondly, the Si-OH group contained in sepiolite can form a covalent bond with Mg of brucite, further improving the interfacial bonding force; and sepiolite can adsorb the gas generated by thermal decomposition, while the rigidity of brucite can inhibit the high-temperature deformation of the material, enhance the stability of the carbon layer structure, so that the composite system still retains a certain strength at 600 °C; in addition, the compounding of sepiolite and expandable graphite can play the main role of flame retardancy and strengthen the flame retardant effect of the fireproof material. 2+ A covalent bond is formed to further improve the interfacial bonding force; moreover, sepiolite can adsorb the gas generated by thermal decomposition, while the rigidity of brucite can inhibit the high-temperature deformation of the material, enhance the stability of the carbon layer structure, so that the composite system still retains a certain strength at 600 °C; in addition, the compounding of sepiolite and expandable graphite can play the main role of flame retardancy and strengthen the flame retardant effect of the fireproof material.

[0009] Preferably, the mass ratio of sepiolite to brucite fiber is 3:1 to 8:1. If sepiolite is not added or brucite fiber is not added, the synergistic effect cannot be generated, resulting in a decrease in the high-temperature stability and flame retardant effect of the inorganic flexible expansion layer; if the addition amount of sepiolite relative to brucite fiber is too much or too little, it will affect the forming effect of the sheet, and also enhance the granularity of the surface quality of the sheet, reduce the tensile strength of the sheet, and increase the ablation rate at high temperature, causing a series of negative effects.

[0010] Preferably, the binder includes but is not limited to white latex and sodium silicate, and the binder can improve the surface strength and early adhesion strength of the inorganic flexible expansion layer sheet.

[0011] Preferably, the plasticizer includes but is not limited to glycerol, and the plasticizer can improve the toughness of the inorganic flexible expansion layer sheet.

[0012] In practical applications, the surface of the inorganic flexible expansion layer can also be treated according to the actual application scenario. A surface treatment agent is coated on the surface of the inorganic flexible expansion layer, such as an anti-wear coating, an explosion-proof coating or a waterproof coating, etc. These coatings can play a role in strengthening the surface of the inorganic flexible expansion layer according to different requirements. For example, when applied to places with waterproof requirements, a waterproof coating can be brushed or sprayed on the surface; when applied to places with explosion-proof requirements, an explosion-proof coating can be brushed or sprayed on the surface; when applied to places with wear-resistant requirements, a material with relatively high hardness or good elasticity such as silica gel, polyurethane, etc. can be brushed on the surface.

[0013] In addition, the silicon-based ceramized outer layer provided by the present invention has a certain structural strength, which can support the inorganic flexible expansion layer, and at the same time has excellent properties such as ultraviolet resistance, resistance to heat and cold alternation, and waterproofness. When a fire occurs, the silicon-based ceramized outer layer can achieve outer layer ceramization through a chemical-physical combination reaction. While absorbing heat, it blocks heat convection to achieve the functions of flame retardancy and fire resistance.

[0014] Combined with the first aspect, the fiber length of the sepiolite is 1-5 mm, the fiber length of the brucite fiber is 10-30 mm, the particle size of the expanded graphite is 30-1000 mesh, and the expansion ratio is 50-500 times; the thickness of the silicon-based ceramic coating is 0.1-2 mm; the thickness of the inorganic flexible expansion layer is 0.25-5 mm.

[0015] At high fire temperatures, expanded graphite can form a structure with high porosity, low thermal conductivity, and high thermal stability in the cavity between the high-temperature resistant fiber substrate of the silicon-based ceramized outer layer and the objects inside the cladding, such as cables, through the synergistic effect between intercalation reaction and high-temperature thermal decomposition, thereby producing a flame retardant effect.

[0016] Combined with the first aspect, the raw materials of the inorganic flexible expansion layer further include at least one of ceramic fiber, glass fiber, and basalt fiber with a length of 0.1-20 mm, and the mass ratio of the ceramic fiber, glass fiber, and basalt fiber is 5 wt%-10 wt%.

[0017] In practical applications, ceramic fiber, glass fiber, and basalt fiber can be incorporated according to actual situations. The long-term temperature resistance of these fibers is at least 300 °C, and the fiber length is longer than that of sepiolite. Their addition can assist in improving the toughness and tensile strength of the composite fireproof material under normal working conditions in non-fire scenarios. At the same time, the addition of these fibers can also play a role in enhancing the thermal stability of the material and filling the internal space structure in the synergistic effect of sepiolite and brucite fiber.

[0018] Combined with the first aspect, the preparation method of the inorganic flexible expansion layer is as follows: According to a preset ratio, the sepiolite and brucite fiber are mixed evenly and microwave-treated for 1-3 min at a microwave power of 400-1000 W; then mixed evenly with the expanded graphite, and a solvent, binder, and plasticizer are added to obtain a slurry, which is stirred evenly until it becomes paste-like; then it is formed by a coating method or a papermaking method to obtain the inorganic flexible expansion layer.

[0019] Among them, the solvent used can be water or a water-alcohol mixture. The inclusion of alcohols (such as ethanol) in the solvent is beneficial to reducing the surface tension and improving the wettability and dispersion uniformity of the fibers used.

[0020] Microwave treatment of sepiolite and brucite fibers (if other fibers are mixed, the same treatment is performed) in advance can remove organic matter, water and other impurities between the materials, expand the micropores between the fiber materials, and be more conducive to the subsequent full mixing and the adsorption of expanded graphite, adhesives and plasticizers by the fiber materials. The power used in microwave treatment needs to be controlled within a certain range. Too high power will cause changes in the physical and chemical properties of the fiber materials, causing the fiber materials to deteriorate and thermally decompose. If the power is too low, impurities such as organic matter and water cannot be completely removed, and the effect of expanding the micropores between the fiber materials cannot be produced, which will lead to a decrease in the strength, toughness and thermal stability of the inorganic flexible expansion layer at high temperatures.

[0021] When the inorganic flexible expansion layer sheet is formed by the coating method or the papermaking method, the coating method is to first stir the slurry into a paste and then evenly apply it on the surface of the base cloth with a coating thickness of 0.25~5mm. If necessary, a layer of non-woven fabric or gauze can be covered on the surface to prevent the coating from cracking. The sheet is then formed by natural drying or baking. The papermaking method is to stir the slurry into a paste and pour it into a screen, and then form it by the traditional papermaking process, and then dehydrate and shape it by natural drying, baking or extrusion.

[0022] Preferably, the substrate fabric used can be selected from at least one of ceramic fiber fireproof fabric, glass fiber fabric, high silica fabric and basalt fiber fabric, with a thickness of 0.2-5 mm and a mass per unit area of 20-5000 g / m 2 .

[0023] In combination with the first aspect, the high temperature resistant fiber substrate is selected from at least one of ceramic fiber fireproof cloth, glass fiber cloth, high silica cloth and basalt fiber cloth, with a thickness of 0.2-5 mm and a mass per unit area of 20-5000 g / m 2 The above-mentioned high temperature resistant fiber substrates all have certain thermal stability and provide mechanical strength for the applied coatings. They are not easy to burn, have good thermal stability, high tensile strength, good toughness, and strong surface adhesion. Their oxygen index is ≥40%, and their long-term temperature resistance is ≥400℃.

[0024] In combination with the first aspect, the silicon-based ceramic coating includes 30wt%~60wt% of a silica gel matrix, 20wt%~40wt% of aluminum oxide, 15wt%~30wt% of glass powder or glass microbeads, 0.5wt%~2wt% of zinc oxide and 0.3wt%~3wt% of a curing agent.

[0025] The coating matrix of the silicon-based ceramic coating provided by the present invention is silica gel. Different from the existing scheme of directly making the cable sheath flame retardant and fire resistant, the silica gel matrix used in the present invention has the function of bonding and solidifying the effective ingredients; moreover, silica gel has good properties such as UV resistance, resistance to alternating hot and cold, and water resistance, good elasticity, and good adhesion to high-temperature resistant fiber substrates. In addition, silica gel will pyrolyze under high temperature conditions of fire to form amorphous SiO2, thereby enhancing the flame retardant effect.

[0026] In addition, the silicon-based ceramic coating provided by the present invention also adds aluminum oxide, glass powder or glass microbeads and zinc oxide. Among them, aluminum oxide reacts with SiO2 formed by silica gel under high temperature conditions of fire to generate ceramic phase materials, forming the structural strength of the coating under high temperature of fire, and at the same time reduces the transfer of fire heat to the objects inside the coating by blocking heat convection and reducing radiant heat. Glass powder or glass microbeads can achieve ceramicization or quasi-ceramicization reaction at a lower temperature through physical-chemical synergistic reactions such as melting within 300~800℃, fill the temperature difference between the high-temperature resistant fiber substrate and the ceramicization of silica gel and aluminum oxide in the late stage of fire, and realize fire protection of objects in the coating in the middle stage of fire or low load fire scenes. Zinc oxide has ultraviolet shielding and free radical quenching functions, can absorb ultraviolet rays with a wavelength less than 387nm, convert them into harmless heat energy, and reduce the breakage of silica gel molecular chains; at the same time, the ZnO surface can capture free radicals excited by ultraviolet rays and inhibit the occurrence of oxidation reactions. Moreover, ZnO also has the function of interface enhancement and moisture barrier. ZnO combines with the Si-OH group of silica gel through surface hydrogen bonds to form a dense protective layer on the surface of the high-temperature resistant fiber substrate, blocking the penetration of water vapor. Therefore, the addition of zinc oxide can effectively improve the UV resistance and moisture resistance. In the UV resistance, under the UV lamp irradiation test conditions, obvious cracks appeared on the surface of the coating without zinc oxide, and the tensile strength loss rate was about 42%; after adding zinc oxide powder, the number and width of surface cracks after irradiation were significantly reduced, and the tensile strength loss rate was about 28%. After being placed under high temperature and high humidity (75℃, 95%RH) conditions for 30 days, the coating without zinc oxide showed obvious adhesion, and no adhesion appeared after adding zinc oxide.

[0027] In combination with the first aspect, the preparation steps of the silicon-based ceramic outer layer include: premixing zinc oxide and silica gel, adding silane coupling agent ethanol solution, stirring thoroughly to ensure that the zinc oxide is evenly dispersed, then adding aluminum oxide, and glass powder or glass beads, stirring evenly, adding a curing agent and continuing to stir evenly to obtain a liquid coating, and then evenly applying the liquid coating to one side of the high-temperature resistant fiber substrate by roller coating, scraping, brushing or rolling, and allowing the coating to fully react and solidify on the high-temperature resistant fiber substrate by natural standing or baking acceleration.

[0028] Among them, during coating, it can be single - sheet coating or continuous coating production through a roller linkage method. In places with lower fire protection requirements, the silicon - based ceramized outer layer can also be simply replaced with a single - sided or double - sided silicone cloth of the same thickness. According to actual needs, an appropriate amount of colorants and fillers can also be added to the silicone.

[0029] Combined with the first aspect, the composite fire - proof material further includes an inner decorative layer, and the inorganic flexible expansion layer is sandwiched between the inner decorative layer and the silicon - based ceramized outer layer.

[0030] The decorative inner layer has the functions of protecting the inorganic flexible expansion layer, improving the aesthetics of the product, and improving the weather resistance of the product. The inner decorative layer can be made of materials such as fiberglass cloth, basalt fiber cloth, or ceramic fiber cloth with good thermal stability. In actual applications, the inner decorative layer is used on the side of the composite fire - proof material facing the object to be coated and is in direct contact with the object to be coated. According to the needs of the application scenario, the inner decorative layer can be selectively set. For fire - proof materials without an inner decorative layer, their fire - proof and flame - retardant properties will not be affected. When the actual application scenario has a high requirement for the fire - proof grade or the fire - affected surface is uncertain, the silicon - based ceramized outer layer can be used to replace the inner decorative layer, and at this time, the entire composite fire - proof material forms a completely symmetric structure.

[0031] The second aspect of the present invention provides a preparation method of the above - mentioned flexible fire - resistant, flame - retardant inorganic expansion composite fire - proof material, specifically: using high - temperature - resistant flame - retardant threads to stitch the inorganic flexible expansion layer and the silicon - based ceramized outer layer.

[0032] For the composite fire - proof material containing an inner decorative layer, use high - temperature - resistant flame - retardant threads to stitch the silicon - based ceramized outer layer and the inner decorative layer with the inorganic flexible expansion layer sandwiched between them.

[0033] Combined with the second aspect, the interval of the high - temperature - resistant flame - retardant threads is 1 - 100 cm, and the edges of the composite fire - proof material are edge - stitched as needed.

[0034] In actual applications, if the use scenario of the composite fire - proof material is to be placed vertically after being unfolded, in order to ensure the structural stability of the composite fire - proof material, stitching should be carried out at least along the horizontal parallel direction during stitching.

[0035] The third aspect of the present invention provides an application of the above - mentioned flexible fire - resistant, flame - retardant inorganic expansion composite fire - proof material in steel cable fire protection, cable tray fire protection, steel structure fire protection, aluminum alloy structure fire protection, concrete structure fire protection, wood structure flame retardant and fire protection, fire - proof plugging, lithium - battery fire protection, new energy vehicle and energy storage facility fire protection, specifically: covering the object to be fire - protected with the composite fire - proof material by means of bundling and fixing, Velcro fixing, button fixing, or mechanical fixing.

[0036] The present invention has developed a flexible high-performance fire-resistant and flame-retardant material. In addition to being applied in the field of cable fire protection, this material can also be used in fields that require fire compartmentalization and fire separation, such as building fire separation, fireproof plugging of holes in power facilities, and fire separation of new energy vehicles and facilities.

[0037] Preferably, for the bundling and fixing method, metal material straps such as stainless steel or non-metal material straps such as high-temperature resistant fibers can be used to bundle the composite fireproof material coating on the surface of the object to be fire-protected. For the Velcro fixing method, the composite fireproof material with an appropriate width can be cut according to the engineering needs. The A and B sides of the flame-retardant Velcro are respectively sewn at both ends of the composite fireproof material with high-temperature resistant threads, and an enclosing structure for the protected object is formed through the Velcro. For the button fixing method, the composite fireproof material with an appropriate width is cut according to the engineering needs, and both ends are fixed through buttons (such as disc buttons, snap buttons, etc.) to form an enclosing structure for the protected object. For the mechanical fixing method, the composite fireproof material with an appropriate width is cut according to the engineering needs, and the composite fireproof material is directly fixed on the surface of the protected object through mechanical fixing methods such as pressure strips and screws.

[0038] The beneficial effects of the present invention: Through the specific selection of materials and the special setting of the structure, the present invention obtains a composite fireproof material that simultaneously has fire-resistant and flame-retardant functions. The oxygen index of this composite fireproof material is ≥40%, the smoke toxicity can reach AQ2 level, and the smoke density rating SDR≤3. It is not easy to burn, has low smoke toxicity, and extremely low smoke production in a fire, and has excellent weather resistance and environmental adaptability. At the same time, this composite fireproof material also has excellent insulation performance. According to the actual application scenario, live construction can be carried out when the voltage meets the conditions, which is very suitable for the fireproof upgrading and renovation projects of existing projects. After the composite fireproof material is coated on the surface of the object to be protected, such as a cable, the flame-retardant grade is significantly improved compared to before coating (from B3 level to B1 level), the fire-resistant time is significantly extended (from 6 minutes of the base material cable to 105 minutes of continuous fire resistance), and the fire-resistant time limit is at least 240 minutes. In addition, this composite fireproof material can not only be used for the flame retardant and fire protection of cables in new projects, but also for the fireproof upgrading of existing projects or flexible fire partitions in new energy scenarios, etc., and has broad application prospects. Description of the Drawings

[0039] Figure 1 It is a photo of the physical object of the composite fireproof material obtained in Example 3 of the present invention; Figure 2 It is a photo of the physical object of the composite fireproof material obtained in Example 1 of the present invention before coating the base material cable; Figure 3 It is a on-site photo at the start time of the fire resistance test after the composite fireproof material obtained in Example 1 of the present invention is coated on the base material cable; Figure 4 This is a on-site photo of the fire-resistant test for 240 minutes after the base cable is coated with the composite fireproof material obtained in Example 1 of the present invention; Figure 5 This is a photo of the monitor device display during the 240-minute fire-resistant test after the base cable is coated with the composite fireproof material obtained in Example 1 of the present invention; Figure 6 This is a photo of the monitor device during the 240-minute fire-resistant test after the base cable is coated with the composite fireproof material obtained in Example 1 of the present invention; Figure 7 This is a photo of the physical object of the coated body after the 240-minute fire-resistant test of the base cable coated with the composite fireproof material obtained in Example 1 of the present invention. Detailed implementation manners

[0040] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] Those skilled in the art of the present technology can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those of ordinary skill in the technical field to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless specifically defined.

[0042] Currently, the products for cable fire protection cannot simultaneously take into account the functions of flame retardancy and fire resistance. It is difficult to ensure the consistency of product quality. The flame retardant effect of fireproof coatings is easily affected by construction quality and environmental factors. The coatings are prone to cracking and peeling, and the actual service life is relatively short. Moreover, the compatibility of coatings of different batches or formulations is poor, resulting in difficulty in live working when repairing coatings or improving the fire protection level, and it is necessary to replace the cable or shut down; the existing flame retardant / fire resistant materials (such as cable bodies or coatings) are not recyclable, which does not conform to the concept of circular economy; in addition, most of the existing flame retardant or fire resistant materials use organic substances as carriers, having the disadvantages of large smoke generation and high toxicity during combustion, being prone to causing asphyxiation of personnel in fires, and serious secondary hazards; and the current fireproof materials cannot protect cables from high-temperature losses, the post-disaster repair cost is relatively high, and at the same time, they lack the "active" fire extinguishing function and cannot efficiently suppress the spread of fire.

[0043] The existing "cable flame retardant tape" products mainly use substrates such as PVC, EVA or ethylene propylene diene monomer rubber, etc., with relatively high smoke toxicity and large smoke production; and it can only be used for cable flame retardancy, unable to achieve cable fire prevention. At the same time, it requires winding construction, and the risk of live construction is relatively large. For existing projects where cables need to be moved, the construction difficulty is great.

[0044] In view of this, the present invention provides a flexible fire-resistant and flame-retardant inorganic expanded composite fireproof material. This composite fireproof material simultaneously has flame retardant and fire-resistant functions, has the advantages of high self-oxygen index, less smoke production, and low smoke toxicity. At the same time, it also has excellent weather resistance and insulation performance, can upgrade other objects such as cables that do not have fireproof functions to a higher flame retardant grade and fire-resistant grade, and has a great cost advantage; moreover, for cables with existing fireproof coatings, this composite fireproof material will not show incompatibility with the existing coatings, and is very suitable for fireproof upgrading and renovation projects of existing projects.

[0045] Unless otherwise specified, the chemical reagents, raw materials, and mechanical equipment used in the following examples and comparative examples are all conventional commercially available products.

[0046] Example 1 This example provides a flexible fire-resistant and flame-retardant inorganic expanded composite fireproof material, which includes a closely adhered silicon-based ceramicized outer layer, an inorganic flexible expansion layer, and an inner decoration layer stitched with high-temperature resistant flame retardant wires. The raw materials of the silicon-based ceramicized outer layer include ceramic fiber fireproof cloth (thickness 3 - 4 mm) and a 0.5 - 1.5 mm thick silicon-based ceramic coating coated on the surface of the ceramic fiber fireproof cloth. The silicon-based ceramic coating includes 40 wt% silica gel, 30 wt% alumina, 28 wt% glass powder, 1.5 wt% zinc oxide, and 0.5 wt% curing agent; the thickness of the inorganic flexible expansion layer is 3 - 4 mm, and the raw materials include: 50 wt% sepiolite (fiber length 1 - 5 mm), 10 wt% brucite fiber (fiber length 10 - 30 mm), 5 wt% ceramic fiber (length 2 - 10 mm), 20 wt% expanded graphite (particle size 500 mesh, expansion ratio 200 times), 10 wt% white latex, and 5 wt% glycerol.

[0047] Among them, the preparation method of the silicon-based ceramicized outer layer is as follows: S1. Extension of the high-temperature resistant fiber substrate before coating: Lay the ceramic fiber fireproof cloth flat on the coating platform.

[0048] S2. Preparation of the outer coating material: Premix zinc oxide and silica gel, add 1% silane coupling agent ethanol solution, and stir well with a stirrer to ensure uniform dispersion of zinc oxide. Pour the mixture of silica gel and zinc oxide powder into a stirring tank, add alumina and glass powder, stir to make them evenly distributed in the silica gel, add the curing agent and stir evenly to obtain the coating.

[0049] S3. Coating the outer coating: The coating obtained in step S2 is evenly applied to one side of the ceramic fiber fireproof cloth by roll coating, and left to stand naturally to allow the coating to fully react and cure on the ceramic fiber fireproof cloth.

[0050] The preparation method of the inorganic flexible expansion layer is as follows: S1. Microwave pretreatment: A mixture of sepiolite, brucite fiber and ceramic fiber is stirred at room temperature in a drum for 30 min to fully mix the three fiber powders, and then placed in a microwave oven for microwave treatment. The treatment conditions are 2 min of microwave power treatment at 600 W for every 10 kg of the mixture.

[0051] S2. Slurry preparation: The above three kinds of high-temperature formed fibers pretreated and expanded graphite are mixed, and water, white latex and glycerol are added and stirred until it becomes a uniform paste.

[0052] S3. Sheet forming: The slurry obtained in step S2 is evenly applied to the surface of the ceramic fiber fireproof cloth by the coating method, with a coating thickness of 0.5 - 3 mm. A layer of non-woven fabric is covered on the surface to prevent cracking, and it is naturally dried to form a sheet.

[0053] The inner decorative layer used is fiberglass cloth.

[0054] Example 2 This example provides a flexible fireproof, flame-retardant inorganic expansion composite fireproof material. The composite fireproof material includes a closely adhered silicon-based ceramized outer layer and an inorganic flexible expansion layer stitched with high-temperature resistant flame-retardant wires. The raw materials of the silicon-based ceramized outer layer include fiberglass cloth (thickness 1 - 2.5 mm) and a 0.1 - 1 mm thick silicon-based ceramic coating coated on the surface of the fiberglass cloth. The silicon-based ceramic coating includes 30 wt% silica gel, 40 wt% alumina, 27 wt% glass microspheres, 0.5 wt% zinc oxide, and 2.5 wt% curing agent; the thickness of the inorganic flexible expansion layer is 0.3 - 2 mm, and the raw materials include: 60 wt% sepiolite (fiber length 1 - 5 mm), 5 wt% brucite fiber (fiber length 10 - 30 mm), 10 wt% fiberglass (length 2 - 5 mm), 10 wt% expanded graphite (particle size 50 mesh, expansion ratio 50 times), 14 wt% sodium silicate, and 1 wt% glycerol.

[0055] Among them, the preparation method of the silicon-based ceramized outer layer is as follows: S1. Stretching before coating the high-temperature resistant fiber substrate: Lay the fiberglass cloth flat on the coating platform.

[0056] S2. Preparation of the outer coating material: Premix zinc oxide and silica gel, add 1% ethanol solution of silane coupling agent, and stir well with a stirrer to ensure uniform dispersion of zinc oxide. Pour the mixture of silica gel and zinc oxide powder into a stirring tank, add alumina and glass beads, and stir to make them evenly distributed in the silica gel. Then add a curing agent and stir evenly to obtain the coating.

[0057] S3. Coating the outer layer: Apply the coating obtained in step S2 evenly on one side of the fiberglass cloth by roll coating, and let it stand naturally to allow the coating to fully react and cure on the fiberglass cloth.

[0058] The preparation method of the inorganic flexible expansion layer is as follows: S1. Microwave pretreatment: Stir the mixture of sepiolite, brucite fiber and fiberglass in a drum at room temperature for 20 min to fully mix the three fiber powders, and then put it into a microwave oven for microwave treatment. The treatment conditions are to treat with a microwave power of 1000 W for 1 min for every 10 kg of the mixture.

[0059] S2. Slurry preparation: Mix the above three kinds of high-temperature molding fibers pretreated with expanded graphite, add water, white latex and glycerin, and stir until it becomes a uniform paste.

[0060] S3. Sheet forming: Apply the slurry obtained in step S2 evenly on the surface of the fiberglass cloth by the coating method, with a coating thickness of 1 - 2 mm, cover a layer of non-woven fabric on the surface to prevent cracking, and let it dry naturally to form the sheet.

[0061] Example 3 This example provides a flexible fireproof, flame-retardant inorganic expansion composite fireproof material. The composite fireproof material includes a closely adhered silicon-based ceramicized outer layer, an inorganic flexible expansion layer and an inner decorative layer stitched with high-temperature resistant and flame-retardant threads. Among them, the inorganic flexible expansion layer is sandwiched between the silicon-based ceramicized outer layer and the inner decorative layer as the middle layer. The raw materials of the silicon-based ceramicized outer layer include basalt fiber cloth (thickness 3 - 5 mm) and a 0.2 - 2 mm thick silicon-based ceramic coating coated on the surface of the basalt fiber cloth. The silicon-based ceramic coating includes 60 wt% silica gel, 20 wt% alumina, 17 wt% glass powder, 2 wt% zinc oxide, and 1 wt% curing agent; the thickness of the inorganic flexible expansion layer is 3 - 4 mm, and the raw materials include: 40 wt% sepiolite (fiber length 1 - 5 mm), 25 wt% brucite fiber (fiber length 10 - 30 mm), 5 wt% basalt fiber (length 2 - 10 mm), 24 wt% expanded graphite (particle size 1000 mesh, expansion ratio 500 times), 5 wt% white latex and 1 wt% glycerin.

[0062] Among them, the preparation method of the silicon-based ceramicized outer layer is as follows: S1. Pre - stretching of the high - temperature - resistant fiber substrate before coating: Lay the basalt fiber cloth flat on the coating platform.

[0063] S2. Preparation of the outer - layer coating material: Premix zinc oxide and silica gel, add 1% ethanol solution of silane coupling agent, and stir thoroughly with a stirrer to ensure uniform dispersion of zinc oxide. Pour the mixture of silica gel and zinc oxide powder into a stirring tank, add alumina and glass powder, stir to make them evenly distributed in the silica gel, add a curing agent and stir evenly to obtain the coating.

[0064] S3. Coating the outer - layer: Apply the coating obtained in step S2 evenly on one side of the basalt fiber cloth by rolling, and let it stand naturally to allow the coating to fully react and cure on the basalt fiber cloth.

[0065] The preparation method of the inorganic flexible expansion layer is as follows: S1. Microwave pretreatment: Stir the mixture of sepiolite, brucite fiber and basalt fiber in a drum at room temperature for 30 min to fully mix the three kinds of fiber powders, and then put it into a microwave oven for microwave treatment. The treatment conditions are to use a microwave power of 400 W to treat 3 min for every 10 kg of the mixture.

[0066] S2. Slurry preparation: Mix the above - mentioned three kinds of high - temperature - formed fibers pretreated with expanded graphite, add a mixed solution of ethanol and water, white latex and glycerin, and stir until it becomes a uniform paste.

[0067] S3. Sheet forming: Apply the slurry obtained in step S2 evenly on the surface of the high - silica cloth by the coating method, with a coating thickness of 0.5 - 3 mm, cover a layer of non - woven fabric on the surface to prevent cracking, and let it dry naturally to form the sheet.

[0068] The inner decorative layer used is glass fiber cloth.

[0069] Comparative Example 1 This comparative example provides a flexible fire - resistant, flame - retardant inorganic expansion composite fire - proof material. The composition and structure of this composite fire - proof material are basically similar to those of Example 1, with the only difference being that the raw materials for preparing the inorganic flexible expansion layer do not contain sepiolite, but replace it with an equal amount of brucite fiber, and the composition of the remaining raw materials and the preparation method are the same as those of Example 1.

[0070] Comparative Example 2 This comparative example provides a flexible fire - resistant, flame - retardant inorganic expansion composite fire - proof material. The composition and structure of this composite fire - proof material are basically similar to those of Example 1, with the only difference being that the mass ratio of sepiolite in the inorganic flexible expansion layer is 58 wt% and the mass ratio of brucite fiber is 2 wt%, and the composition of the remaining raw materials and the preparation method are the same as those of Example 1.

[0071] Comparative Example 3 This comparative example provides a flexible fire-resistant, flame-retardant inorganic expanded composite fireproof material. The composition and structure of this composite fireproof material are the same as those of Example 1, except that: when preparing the inorganic flexible expansion layer, sepiolite, brucite fiber, and ceramic fiber were not subjected to microwave pretreatment but were directly used for the preparation of the slurry, and the remaining preparation methods were the same as those of Example 1.

[0072] Comparative Example 4 This comparative example provides a cable with a fireproof coating on its surface. The base cable is a cross-linked polyethylene insulated polyethylene sheathed power cable YJV22 - 0.6 / 1kV - 3*50 + 1*25 commonly used in engineering. The components of the fireproof coating applied on the surface of this base cable include 10wt% - 40wt% ammonium polyphosphate, 5wt% - 20wt% melamine, 2wt% - 12wt% pentaerythritol, and 10wt% - 30wt% acrylic emulsion, and the balance is a mixed solution of ethanol and water. The coating thickness is 1 mm.

[0073] Comparative Example 5 This comparative example provides a cable sleeved with a protective sleeve. The base cable is a cross-linked polyethylene insulated polyethylene sheathed power cable YJV22 - 0.6 / 1kV - 3*50 + 1*25 commonly used in engineering. The material of the protective sleeve used is glass fiber with a silicone coating on the surface and a ceramic fiber cloth lining, and the thickness is 3 - 4 mm.

[0074] Inspection Example The composite fireproof materials obtained in Examples 1 - 3 and Comparative Examples 1 - 3 were respectively bundled and wrapped on the surface of a cross-linked polyethylene insulated polyethylene sheathed power cable YJV22 - 0.6 / 1kV - 3*50 + 1*25 without flame-retardant function, which is commonly used in engineering, using tie straps made of high-temperature resistant fiber materials, and the fire resistance and flame retardancy performances were actually measured. At the same time, the uncoated base cable was used as a control, and the following performances of the different cables provided in Comparative Examples 4 - 5 were tested.

[0075] Among them, the flame retardant grades of the cable before and after coating are tested according to GB 31247-2014 "Classification of the Burning Performance of Cables and Optical Cables"; the fire resistance grades of the cable before and after coating are tested according to GB / T 19216.21-2003 "Circuit Integrity Tests of Cables or Optical Cables under Fire Conditions - Part 21: Test Procedures and Requirements - Cables with Rated Voltage of 0.6 / 1.0 kV and Below"; the weather resistance test 1 includes corrosiveness, water resistance, oil resistance, acid resistance, water resistance, damp heat resistance, and freeze-thaw cycle tests carried out according to GB 23864-2023 "Fireproof Sealing Materials"; the weather resistance test 2 includes heat exposure resistance, damp heat resistance, freeze-thaw cycle resistance, acid resistance, alkali resistance, salt spray corrosion resistance, and ultraviolet radiation resistance carried out according to GB 14907-2018 "Fireproof Coating for Steel Structures"; oil resistance, salt water resistance, damp heat resistance, and freeze-thaw cycle tests are carried out according to GB 28374-2012 "Cable Fireproof Coating", the smoke toxicity of the material is tested according to GB / T 20285-2006 "Hazard Classification of the Smoke Toxicity of Materials", the oxygen index of the material is tested according to GB / T 2406.2-2009 "Plastics - Determination of the Burning Behavior by the Oxygen Index Method - Part 2: Room Temperature Test", the smoke density grade of the material is tested according to GB / T 20284-2006 "Single Burning Test of Building Materials or Products", and the insulation performance of the material is tested using a multimeter. The test results are shown in Table 1.

[0076] Table 1

[0077] As can be seen from Table 1, compared with the non-fire-resistant base material cable, Examples 1 to 3 not only do not reduce the weather resistance, but also significantly improve the combustion performance. More importantly, according to the cable fire resistance test method, the coated silicon-based coating material provided by the present invention fully meets the requirements of fire-resistant cables. At the same time, the fire resistance limit time exceeds 240 min, the smoke toxicity is improved from ZA3 level of the base material cable outer skin to AQ2 level, the smoke density is reduced to ≤3, and the insulation performance does not significantly decay.

[0078] Comparing Example 1 with Comparative Examples 1 to 2, it can be seen that when significant changes occur in the components and the components cannot cooperate with each other, the physical and chemical properties / weather resistance and combustion performance of the obtained composite fireproof material all decline; the smoke density grade and smoke toxicity both decrease to varying degrees. At the same time, for the relatively key fire resistance performance, although the composite fireproof materials obtained in Comparative Examples 1 to 2 still meet the requirements of the fire-resistant cable test, compared with Example 1, their fire resistance limit times are significantly shortened.

[0079] Comparing Example 1 with Comparative Example 3, it can be seen that when sepiolite, brucite fiber and ceramic fiber are not subjected to the microwave pretreatment process, their weather resistance, fire resistance limit and smoke density grade are all reduced, indicating that pre-microwave pretreatment of inorganic fibers has an obvious improvement effect on the fire resistance and smoke density of the final composite fireproof material.

[0080] Comparing Examples 1 to 3 with Comparative Example 4, which is a commonly used cable fire protection method at present - applying cable fireproof paint on the surface of the base cable, it can be seen that in addition to solving the problems of difficult construction and inability to work live of cable fireproof paint, the present invention also solves the problem of poor weather resistance of cable fireproof paint. At the same time, the present invention has a greater improvement in the fire resistance limit, smoke toxicity and smoke density grade than Comparative Example 4.

[0081] Comparing Examples 1 to 3 with Comparative Example 5, which is a commonly used cable protection and fire prevention method at present - covering the outer surface of the base cable with a cable protection sleeve, it can be seen that the flame retardancy of Comparative Example 5 is poorer than that of the present invention. At the same time, although the fire resistance limit is improved compared with the base cable, it still cannot meet the performance indicators of fire-resistant cables, and there is a large gap in fire resistance and flame retardancy compared with the present invention.

[0082] In addition, the photos during the fire resistance limit test are respectively as Figures 1 to 5 shown, among which, Figure 1 is the composite fireproof material provided by Example 3 of the present invention, which from top to bottom are the inner decoration layer, the inorganic flexible expansion layer and the silicon-based ceramicized outer layer; Figure 2 is a on-site photo before bundling and covering the above-mentioned base cable with the composite fireproof material obtained in Example 1; Figure 3 and Figure 4 are respectively the on-site photos after bundling and covering the above-mentioned base cable with the composite fireproof material obtained in Example 1 and after continuously conducting the fire resistance test for 240 min; Figure 5 and Figure 6 are respectively the photos of the monitor display and the monitoring equipment during the fire resistance test; Figure 7 is a physical photo of the cable after 240 min of fire resistance test. It can be seen from Figures 2 to 7 that after covering the base cable without flame retardancy performance with the composite fireproof material provided by the present invention and after a fire resistance test of up to 240 min, the composite fireproof material will expand, but it does not burn itself, and the base cable wrapped inside is intact, indicating that the composite fireproof material provided by the present invention has excellent flame retardancy and fire resistance, and can protect the covered object from being ignited for a long time. At the same time, from Figure 4It can be seen that during the fire resistance test, there was no large amount of black smoke or thick smoke, which also indicates that the smoke toxicity and smoke density grade of this composite fireproof material are relatively low, providing a strong guarantee for the affected people to quickly and safely escape from the fire scene in the event of an actual fire. From Figure 6 It can be seen that the base material cable protected by the composite fireproof material can always remain powered on (the full brightness of the 4 red light bulbs in the top row represents that the cable still remains powered on), indicating that after the base material cable is coated with the composite fireproof material, even in the event of a fire, the base material cable can maintain a normal working state for a long time, reducing the losses caused by power failure due to the fire.

[0083] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A flexible fireproof, flame-retardant inorganic expanding composite fireproof material, characterized in that, It includes a closely fitting silicon-based ceramized outer layer and an inorganic flexible expansion layer; Among them, the silicon-based ceramized outer layer includes a high-temperature resistant fiber substrate and a silicon-based ceramic coating coated on the surface of the high-temperature resistant fiber substrate; The inorganic flexible expansion layer is an expanded sheet made by a slurry dehydration process, and the raw materials include 40wt% - 60wt% of sepiolite, 5wt% - 25wt% of brucite fiber, 10wt% - 30wt% of expanded graphite, 5wt% - 20wt% of binder, and 1wt% - 10wt% of plasticizer.

2. The flexible fire-resistant, flame-retardant inorganic expanded composite fireproof material according to claim 1, characterized in that, The fiber length of the sepiolite is 1 - 5mm, the length of the brucite fiber is 10 - 30mm, the particle size of the expanded graphite is 30 - 1000 mesh, and the expansion ratio is 50 - 500 times; the thickness of the silicon-based ceramic coating is 0.1 - 2mm; the thickness of the inorganic flexible expansion layer is 0.25 - 5mm.

3. The flexible fire-resistant, flame-retardant inorganic expanded composite fireproof material according to claim 1, characterized in that, The raw materials of the inorganic flexible expansion layer further include at least one of ceramic fiber, glass fiber, and basalt fiber with a length of 0.1 - 20mm, and the mass ratio of the ceramic fiber, glass fiber, and basalt fiber is 5wt% - 10wt%.

4. The flexible fireproof, flame-retardant inorganic expanded composite fireproof material according to claim 1, wherein, The preparation method of the inorganic flexible expansion layer is as follows: Mix the sepiolite and brucite fiber evenly according to a preset ratio, and perform microwave treatment for 1 - 3min at a microwave power of 400 - 1000W; Then mix it evenly with the expanded graphite, add a solvent, a binder, and a plasticizer to obtain a slurry, and stir evenly until it becomes paste-like; Then use the coating method or the papermaking method for forming to obtain the inorganic flexible expansion layer.

5. The flexible fireproof, flame-retardant inorganic expanded composite fireproof material according to any one of claims 1 to 3, characterized in that, The high-temperature resistant fiber substrate is selected from at least one of ceramic fiber fireproof cloth, fiberglass cloth, high silica cloth and basalt fiber cloth, with a thickness of 0.2 to 5 mm and a mass per unit area of 20 to 5000 g / m 2 .

6. The flexible fireproof, flame-retardant inorganic expanded composite fireproof material according to any one of claims 1 to 3, characterized in that, The silicon-based ceramic coating includes 30wt% - 60wt% of silica gel matrix, 20wt% - 40wt% of alumina, 15wt% - 30wt% of glass powder or glass microspheres, 0.5wt% - 2wt% of zinc oxide, and 0.3wt% - 3wt% of curing agent.

7. The flexible fireproof, flame-retardant inorganic expanded composite fireproof material according to claim 1, wherein The composite fireproof material further includes an inner decoration layer, and the inorganic flexible expansion layer is sandwiched between the inner decoration layer and the silicon-based ceramized outer layer.

8. The preparation method of the flexible fireproof, flame-retardant inorganic expanded composite fireproof material according to any one of claims 1 to 6, characterized in that, Suture the inorganic flexible expansion layer and the silicon-based ceramized outer layer with a high-temperature resistant flame-retardant thread.

9. The preparation method of the flexible fire-resistant, flame-retardant inorganic expanded composite fireproof material according to claim 8, characterized in that, The interval of the high-temperature resistant flame-retardant thread is 1 - 100cm, and the edge of the composite fireproof material is sewn according to needs.

10. Use of the flexible fire-resistant, flame-retardant inorganic expansion composite fireproof material according to any one of claims 1 to 7 in fire protection of steel cables, fire protection of cable trays, fire protection of steel structures, fire protection of aluminum alloy structures, fire protection of concrete structures, flame retardancy and fire protection of wood structures, fireproof sealing, fire protection of lithium batteries, fire protection of new energy vehicles and energy storage facilities, characterized in that, Cover the surface of the object to be fireproof protected by bundling and fixing, Velcro fixing, button fixing, or mechanical fixing of the composite fireproof material.

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