Flame-retardant chemical defense layer for airtight flame-retardant chemical defense fabric and application of flame-retardant chemical defense layer

Abstract

The invention relates to the technical field of safety protection materials, and particularly discloses a flame-retardant chemical defense layer for airtight flame-retardant chemical defense fabric and application of the flame-retardant chemical defense layer. The flame-retardant chemical defense layer for the airtight flame-retardant chemical defense fabric sequentially comprises a first composite PE layer, a first TIE layer, a first PA layer, an EVOH layer, a second PA layer, a second TIE layer and a second composite PE layer from outside to inside, and the thickness of the flame-retardant chemical defense layer is 60-70 microns; the raw materials of the first composite PE layer and the second composite PE layer comprise a flame-retardant filler and modified PE, the mass ratio of the flame-retardant filler to the modified PE is 1: (3.5-6), and the raw materials of the flame-retardant filler comprise nano ZrO2 and aluminum hydroxide. The flame-retardant chemical defense layer for the airtight type flame-retardant chemical defense fabric can be used for preparing the airtight type flame-retardant chemical defense fabric, has excellent flame retardance and chemical defense, and can effectively protect workers in the industries of fire fighting, petrochemical engineering, metallurgical casting, electric power and the like in a high-temperature and chemical working environment for a long time.

Description

Technical Field

[0001] The present application relates to the technical field of safety protection materials, and more specifically, to a flame retardant and chemical-proof layer for airtight flame retardant and chemical-proof fabrics and its application. Background Art

[0002] With the advancement of modern science and technology and the improvement of people's living standards, the functional requirements of clothing fabrics in the field of safety and protective materials are becoming increasingly higher. This is especially true for workers in industries such as firefighting, petrochemicals, metallurgy and casting, and electric power, who are exposed to high temperatures and chemical environments for a long time. Flame-retardant fireproof clothing is a vital layer of skin related to life safety. This "skin" must quickly isolate the human body from fire sources and harmful chemicals, playing a vital role in protecting the workers' lives. As a key component of flame-retardant fireproof clothing, the flame-retardant and chemical-resistant layer has a direct impact on the overall protective effect of the flame-retardant and fireproof clothing.

[0003] The flame retardant and chemical protection layer of traditional flame retardant and chemical protection fabrics mainly focuses on improving the flame retardant performance. For example, polyimide flame retardant fibers, flame retardant additions or copolymerization modification technologies are used to achieve flame retardant effects. Although these methods can effectively improve the flame retardant level of the flame retardant and chemical protection layer, they often sacrifice the mechanical properties of the fabric and its resistance to chemical penetration, resulting in significantly insufficient chemical protection performance. For some materials with better chemical protection performance, such as polyurethane fibers, their flame retardant performance is difficult to meet the requirements.

[0004] Regarding the above-mentioned related technologies, the inventors found that in order to enhance the chemical resistance of the flame retardant and chemical protective layer in the existing technology, the commonly used method is to use polymer coating or lamination technology to give the flame retardant and chemical protective layer the ability to resist chemical penetration. However, these coatings often have poor thermal stability. Once they encounter a fire source, they are prone to rapid degradation and even aggravate the fire, reducing the overall safety of the flame retardant and fireproof clothing. This performance imbalance seriously limits the application of flame retardant and chemical protective fabrics in complex environments. Summary of the Invention

[0005] In order to improve the thermal stability of the flame-retardant and chemical-proof layer and enhance the flame-retardant and chemical-proof properties of the flame-retardant and chemical-proof layer, the present application provides a flame-retardant and chemical-proof layer for an airtight flame-retardant and chemical-proof fabric and its application.

[0006] In a first aspect, the present application provides a flame retardant and chemical protective layer for an airtight flame retardant and chemical protective fabric, which adopts the following technical solution: A flame retardant and chemical-proof layer for airtight flame retardant and chemical-proof fabrics, comprising, from the outside to the inside, a composite PE layer, a first TIE layer, a composite PA layer, an EVOH layer, a copolymerized PA layer, a second TIE layer, and a modified PE layer, wherein the thickness of the flame retardant and chemical-proof layer is 60-70 μm; The raw materials of the first composite PE layer include flame retardant filler and modified PE.

[0007] By adopting the above technical solution, the present application adopts a flame retardant and chemical-proof layer with a sandwich structure, and by setting a PE layer, a TIE layer, a PA layer and an EVOH layer, the flame retardant and chemical-proof layer is given excellent flame retardant properties, chemical-proof properties and mechanical properties.

[0008] As the outer layer of the flame-retardant and chemical-protective layer, the composite PE layer directly contacts the external environment and serves as the first barrier to its flame retardancy and chemical resistance. PE is inherently easy to process, possesses good flexibility and impact resistance, and provides the layer with the necessary flexibility. However, PE has a low limiting oxygen index (LOI) and poor flame retardancy. In fire or high-temperature environments, softening or melting of the PE layer can directly compromise the structural integrity of the flame-retardant and chemical-protective layer, significantly reducing its flame retardant and chemical-protective properties and exacerbating the fire hazard. The addition of flame-retardant fillers can significantly address these deficiencies in the PE layer, enhancing its high-temperature stability and flame retardancy. This improved high-temperature stability ensures the structural integrity of the flame-retardant and chemical-protective layer in high-temperature environments, allowing it to better perform its fire and chemical resistance, preventing delamination or failure due to softening or melting of the PE layer. This effectively inhibits flame spread and reduces heat release, ensuring the flame-retardant and chemical-protective layer's effectiveness in high-temperature and complex environments.

[0009] The EVOH layer, as the middle layer, possesses excellent gas barrier properties, effectively preventing the penetration of oxygen, water vapor, other harmful gases, and chemicals, giving the barrier layer excellent chemical resistance. The PA layer, positioned on either side of the EVOH layer, serves as the middle layer of the flame-retardant and chemical-resistant layer, providing primary mechanical support and possessing high thermal stability, maintaining performance in high-temperature environments and enhancing the overall durability and high-temperature performance of the flame-retardant and chemical-resistant layer. The TIE layer, acting as a transition layer between the various functional layers, improves the interlayer bonding between different materials (such as the composite PE layer and the PA layer). Through the layered structural design, the functions of each layer are further optimized, balancing the flame-retardant and chemical-resistant properties of the flame-retardant and chemical-resistant layer, ensuring flame retardancy while enhancing thermal stability and chemical resistance.

[0010] In addition, the thickness of the flame retardant and chemical protection layer is precisely controlled to 60-70μm, while ensuring the lightweight and high performance of the flame retardant and chemical protection layer material.

[0011] Optionally, the mass ratio of the flame retardant filler to the modified PE is 1:(3.5-6), and the raw materials of the flame retardant filler include nano ZrO2 and aluminum hydroxide.

[0012] By adopting the above technical solution, nano ZrO2 has an extremely high melting point (about 2700℃) and thermal stability, and can maintain stable physical and chemical properties under high temperature environment, significantly improving the overall thermal stability of the outer layer of the flame retardant and chemical protective layer, preventing further heat transfer, and preventing the softening and melting of the outer layer of the flame retardant and chemical protective layer, effectively preventing the softening and melting of the outer layer of the flame retardant and chemical protective layer, and ensuring the structural integrity of the flame retardant and chemical protective layer under high temperature and fire environment.

[0013] Furthermore, both nano ZrO2 and aluminum hydroxide have excellent flame retardant properties. Aluminum hydroxide, as a commonly used flame retardant, can decompose and generate aluminum oxide in a fire-fighting environment to form a protective layer, preventing the transfer of oxygen and heat and inhibiting the combustion reaction. Nano ZrO2, as an inert material, can form a stable ceramic protective layer at high temperatures, further enhancing the flame retardant effect of the flame retardant and chemical protective layer. The flame retardant metal oxide and ceramic mixed protective layer have synergistic flame retardancy, giving the flame retardant and chemical protective layer excellent flame retardant properties.

[0014] In addition, nano-sized ZrO2 can be evenly dispersed in the PE matrix as a filler. On the one hand, it enhances the interfacial bonding force between the filler and the matrix. On the other hand, nano-ZrO2 can form a stable network structure in the PE matrix, preventing crack propagation through crack deflection and bridging mechanisms, thereby improving the fracture toughness of the material and significantly improving the puncture resistance of the flame retardant and chemical protective layer at different temperatures.

[0015] Optionally, the method for preparing the flame retardant filler comprises the following steps: S1: Disperse nano ZrO2 in water and ultrasonicate for 25-35 min to prepare a uniform zirconium source suspension of 15-20 g / L; S2: Dissolve Al(NO3)3 in water to prepare a 0.3-0.5 mol / L aluminum source solution; S3: adding the aluminum source solution to the zirconium source suspension, adding ammonia water, adjusting the pH to (9±0.2), stirring the reaction for 2-2.5 hours, collecting the precipitate by centrifugation, washing and drying, and then heat-treating at 300-450°C to obtain nano-ZrO2 particles coated with aluminum hydroxide; S4: Disperse the nano ZrO2 particles coated with aluminum hydroxide in ethanol, add a coupling agent, and react with stirring at 70-80°C for 1-1.5 hours. The concentration of the coupling agent is 3-5%. Then, collect the precipitate by centrifugation, wash and dry.

[0016] By adopting the above technical solution, the flame retardant filler is formed with aluminum hydroxide as the wrapping layer and nano ZrO2 as the core. The design of this wrapping structure effectively solves the problems of interface incompatibility and functional overlap or conflict of multi-component fillers in the mixed structure, and can make the functions of the mixed filler effectively coordinated and maximize the effect.

[0017] On the one hand, this core-shell structure of aluminum hydroxide-encapsulated nano-ZrO2, through physical isolation and staged reaction, allows the flame retardant effects of the two fillers to complement each other over time. Aluminum hydroxide decomposes at 180-200°C, absorbing heat, releasing water vapor, diluting combustible gases, and simultaneously forming an aluminum oxide protective layer. Nano-ZrO2, on the other hand, can form a stable, continuous ceramic protective layer at higher temperatures (>500°C), isolating oxygen and heat transfer. The endothermic decomposition of aluminum hydroxide and the high-temperature protection of nano-ZrO2 form a "staged flame retardant" that covers a wider temperature range and has higher flame retardant efficiency.

[0018] On the other hand, the decomposition of aluminum hydroxide absorbs heat, lowering the surface temperature of the material and delaying the formation of the nano-ZrO2 protective layer, which helps to avoid premature ceramicization that leads to brittleness of the flame-retardant and chemical-resistant layer, and buys time for the high-temperature protection of nano-ZrO2, forming a "gradient thermal protection". Nano-ZrO2 can form a continuous protective layer at higher temperatures in the future, ensuring the thermal stability of the flame-retardant and chemical-resistant layer.

[0019] In addition, after nano-ZrO2 is wrapped by aluminum hydroxide, it undergoes heat treatment to make the structures of the two more stable, forming uniform single core-shell structure particles, which effectively reduces the agglomeration of nano-ZrO2 and avoids the phase separation problem of multi-component fillers.

[0020] Optionally, the coupling agent is a titanate coupling agent selected from any one or more combinations of isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tris(dioctyl phosphate) titanate, isopropyl trioleyl titanate and isopropyl tristearate titanate.

[0021] Optionally, the coupling agent is isopropyl trioleate titanate.

[0022] By adopting the above technical solution and using titanate coupling agent to modify the surface of flame retardant filler particles, the compatibility between the flame retardant filler and the PE matrix is effectively improved, the interfacial bonding force is stronger, and the overall performance stability of the flame retardant and chemical protective layer is further improved.

[0023] Furthermore, the inventors found that isopropyl trioleyl titanate has the best effect when used as a coupling agent. This may be because compared with other titanates, the carboxylic acid group of oleic acid still retains a certain polarity after titanation, and can be combined with the maleic anhydride group in PE-g-MAH through hydrogen bonds or dipole-dipole interactions, and has stronger polarity adaptability; on the other hand, it may be because oleic acid titanate contains a higher content of flexible unsaturated long-chain structure, which is easier to entangle with the PE matrix through flexible chain segments to enhance compatibility. At the same time, the long-chain structure can form steric hindrance, prevent agglomeration between fillers, and improve dispersion uniformity.

[0024] Optionally, the modified PE is PE-g-MAH.

[0025] Optionally, the raw materials of the composite PA layer include copolymerized PA and silicone polyamide elastomer in a mass ratio of 1:(0.1-0.3).

[0026] By adopting the above technical solution, the silicone polyamide elastomer and the copolymerized PA have good compatibility. The amide groups and siloxane segments in the silicone polyurethane elastomer can form a dynamic hydrogen bond network. Under external stimuli such as heat or pressure, the hydrogen bonds can break and recombine to achieve self-repair, which significantly improves the impact resistance and fracture toughness of the PA layer.

[0027] Silicone polyamide elastomer can generate a SiO2 protective layer at high temperature, isolating oxygen and heat transfer and inhibiting the release of combustible gases. The formation of the SiO2 protective layer can also catalyze the carbonization reaction of PA to form a denser carbon layer, further blocking the flame, and working together with the copolymerized PA to further enhance the flame retardancy of the flame retardant and chemical protective layer.

[0028] Optionally, the raw materials of the first TIE layer and the second TIE layer include ethylene-acrylate-maleic anhydride terpolymer.

[0029] In a second aspect, the present application provides an application of a flame retardant and chemical-proof layer for airtight flame retardant and chemical-proof fabrics in the preparation of airtight flame retardant and chemical-proof fabrics.

[0030] In summary, this application has the following beneficial effects: 1. The flame retardant and chemical protection layer of the present application adopts a sandwich structure of 7 layers. By layering the PE layer, TIE layer, PA layer and EVOH layer, the functions of each layer of material are further optimized. The flame retardant and chemical protection layer structure is highly stable, which can balance the flame retardant and chemical protection properties of the flame retardant and chemical protection layer, improve its thermal stability, and ensure that the flame retardant and chemical protection layer has both excellent flame retardant and chemical protection properties.

[0031] 2. In this application, it is preferred to use aluminum hydroxide wrapped nano ZrO2 core-shell wrapped structure particles as flame retardant fillers and composite them with modified PE as the outermost composite PE layer, which effectively reduces the agglomeration of nano ZrO2 and avoids the phase separation problem of multi-component fillers. By utilizing the flame retardant properties and temperature characteristics of aluminum hydroxide and nano ZrO2, "staged flame retardancy" and "gradient thermal protection" are achieved, which significantly improves the overall flame retardancy and thermal protection performance of the flame retardant and chemical protective layer.

[0032] 3. In this application, copolymerized PA and silicone polyamide elastomer are preferably composited as the composite PA layer. The amide groups and siloxane segments in the silicone polyurethane elastomer can form a dynamic hydrogen bond network. Under external stimuli such as heat or pressure, the hydrogen bonds can break and recombine to achieve self-repair, which significantly improves the impact resistance and fracture toughness of the PA layer. At the same time, the silicone polyamide elastomer can generate a SiO2 protective layer at high temperature, further isolating oxygen and heat transfer, and can also catalyze PA to form a denser carbon layer, further improving the flame retardancy and thermal protection performance of the flame retardant and chemical protective layer. DETAILED DESCRIPTION

[0033] The following examples further illustrate the present application in detail. raw material

[0034] Unless otherwise specified, the raw materials used in the examples and comparative examples of this application are all commercially available products, specifically: Nano ZrO2, average particle size is 30nm; PE-g-MAH, selected from Dongguan Zhangmutou Jinyunlai Plastic, TY1060H; Copolymer PA, selected from BASF, C3U copolymer PA66; Silicone polyamide elastomer, selected from Dow Corning, nylon matrix TPSiV; Ethylene-acrylate-maleic anhydride terpolymer selected from Lotader® 4720; EVOH, selected from Japan Kuraray, EVAL™ F; Isopropyl tris(dioctylpyrophosphate) titanate, CAS: 67691-13-8; Isopropyl tris(dioctylphosphoyl) titanate, CAS: 65345-34-8; Isopropyl trioleyl titanate, CAS: 136144-62-2; Isopropyl tristearate titanate, CAS: 61417-49-0. Preparation example of flame retardant filler

[0035] Preparation Example 1 The flame retardant filler, whose raw materials include nano ZrO2 and aluminum hydroxide, and its preparation method includes the following steps: S1: Disperse nano-ZrO2 in water and ultrasonicate at 500W power for 30min to prepare a uniform zirconium source suspension of 18g / L; S2: Dissolve Al(NO3)3 in water to prepare a 0.3 mol / L aluminum source solution; S3: The aluminum source solution is slowly added to the zirconium source suspension under stirring, ammonia water is added, the pH is adjusted to (9±0.2), and the reaction is stirred for 2.5 hours. The precipitate is collected by centrifugation, washed and dried, and then heat-treated at 400°C to obtain nano-ZrO2 particles coated with aluminum hydroxide; S4: Nano ZrO2 particles coated with aluminum hydroxide are dispersed in anhydrous ethanol, a coupling agent is added, and the mixture is stirred and reacted at 80°C for 1.2 hours. The concentration of the coupling agent is 4%. The precipitate is then collected by centrifugation, washed, and dried to obtain the product. The coupling agent used is isopropyl tri(dioctyl pyrophosphate) titanate.

[0036] Preparation Example 2 The flame retardant filler, whose raw materials include nano ZrO2 and aluminum hydroxide, and its preparation method includes the following steps: S1: Disperse nano-ZrO2 in water and ultrasonicate at 500W power for 25min to prepare a uniform zirconium source suspension of 20g / L; S2: Dissolve Al(NO3)3 in water to prepare a 0.5 mol / L aluminum source solution; S3: slowly adding the aluminum source solution to the zirconium source suspension under stirring, adding ammonia water, adjusting the pH to (9±0.2), stirring and reacting for 2 hours, collecting the precipitate by centrifugation, washing and drying, and then heat-treating at 300°C to obtain nano-ZrO2 particles coated with aluminum hydroxide; S4: Nano ZrO2 particles coated with aluminum hydroxide are dispersed in anhydrous ethanol, a coupling agent is added, and the mixture is stirred and reacted at 75°C for 1.5 hours. The concentration of the coupling agent is 4%. The precipitate is then collected by centrifugation, washed, and dried to obtain the product. The coupling agent used is isopropyl tri(dioctyl pyrophosphate) titanate.

[0037] Preparation Example 3 The flame retardant filler, whose raw materials include nano ZrO2 and aluminum hydroxide, and its preparation method includes the following steps: S1: Disperse nano-ZrO2 in water and ultrasonicate at 500W power for 35min to prepare a uniform zirconium source suspension of 15g / L; S2: Dissolve Al(NO3)3 in water to prepare a 0.4 mol / L aluminum source solution; S3: slowly adding the aluminum source solution to the zirconium source suspension under stirring, adding ammonia water, adjusting the pH to (9±0.2), stirring and reacting for 2 hours, collecting the precipitate by centrifugation, washing and drying, and then heat-treating at 450°C to obtain nano-ZrO2 particles coated with aluminum hydroxide; S4: Nano ZrO2 particles coated with aluminum hydroxide are dispersed in anhydrous ethanol, a coupling agent is added, and the mixture is stirred and reacted at 80°C for 1 hour. The concentration of the coupling agent is 3%. The precipitate is then collected by centrifugation, washed, and dried to obtain the product. The coupling agent used is isopropyl tri(dioctyl pyrophosphate) titanate.

[0038] Preparation Example 4 The flame retardant filler, whose raw materials include nano ZrO2 and aluminum hydroxide, and its preparation method includes the following steps: S1: Disperse nano-ZrO2 in water and ultrasonicate at 500W power for 30min to prepare a uniform zirconium source suspension of 18g / L; S2: Dissolve Al(NO3)3 in water to prepare a 0.5 mol / L aluminum source solution; S3: The aluminum source solution is slowly added to the zirconium source suspension under stirring, and ammonia water is added to adjust the pH to (9±0.2). The mixture is stirred for 2.5 hours, and the precipitate is collected by centrifugation, washed and dried, and then heat-treated at 450°C to obtain nano-ZrO2 particles coated with aluminum hydroxide; S4: Nano ZrO2 particles coated with aluminum hydroxide are dispersed in anhydrous ethanol, a coupling agent is added, and the mixture is stirred and reacted at 70°C for 1.5 hours. The concentration of the coupling agent is 5%. The precipitate is then collected by centrifugation, washed, and dried to obtain the product. The coupling agent used is isopropyl tri(dioctyl pyrophosphate) titanate.

[0039] Preparation Example 5 The flame retardant filler is different from Preparation Example 1 in that the coupling agent used in step S4 is isopropyl tris(dioctylphosphoyl) titanate, and the other steps are the same as Preparation Example 1.

[0040] Preparation Example 6 The flame retardant filler is different from Preparation Example 1 in that the coupling agent used in step S4 is isopropyl trioleate acyloxy titanate, and the other steps are the same as Preparation Example 1.

[0041] Preparation Example 7 The flame retardant filler is different from Preparation Example 1 in that the coupling agent used in step S4 is isopropyl tristearate titanate, and the other steps are the same as Preparation Example 1.

[0042] Preparation Example 8 The flame retardant filler, whose raw materials include nano ZrO2 and aluminum hydroxide, is different from Preparation Example 1 in that its preparation method includes the following steps: Nano ZrO2 and aluminum hydroxide in a mass ratio of 1:1.3 were dispersed in anhydrous ethanol, ultrasonicated at a power of 500W for 30 minutes, and then a coupling agent was added. The mixture was stirred and reacted at 80°C for 1.2 hours. The concentration of the coupling agent was 4%. The precipitate was collected by centrifugation, washed, and dried to obtain the product. The coupling agent used was isopropyl tri(dioctyl pyrophosphate) titanate.

[0043] Preparation Example 9 The flame retardant filler is different from Preparation Example 1 in that the dried product is not heat-treated in step S3. The specific operation of step S3 is as follows: The aluminum source solution was slowly added to the zirconium source suspension under stirring, and ammonia water was added to adjust the pH to (9±0.2). The mixture was stirred for 2.5 hours, and the precipitate was collected by centrifugation, washed, and dried to obtain nano-ZrO2 particles coated with aluminum hydroxide. The other steps are the same as those in Preparation Example 1.

[0044] Preparation Example 10 Flame retardant filler, the raw material of the flame retardant filler is nano ZrO2, and the difference from Preparation Example 1 is that the preparation method thereof comprises the following steps: Nano ZrO2 was dispersed in ethanol, ultrasonicated at 500W power for 30 minutes, and then a coupling agent was added. The reaction was stirred at 80°C for 1.2 hours. The concentration of the coupling agent was 4%. The precipitate was collected by centrifugation, washed, and dried to obtain the product. The coupling agent used was isopropyl tri(dioctyl pyrophosphate) titanate.

[0045] Preparation Example 11 Flame retardant filler, the raw material of the flame retardant filler is aluminum hydroxide. The difference from Preparation Example 1 is that the preparation method thereof comprises the following steps: Aluminum hydroxide was dispersed in ethanol, ultrasonicated at 500 W for 30 minutes, and then a coupling agent was added. The reaction was stirred at 80°C for 1.2 hours. The concentration of the coupling agent was 4%. The precipitate was collected by centrifugation, washed, and dried to obtain the product. The coupling agent used was isopropyl tri(dioctyl pyrophosphate) titanate.

[0046] Preparation Example 12 The flame retardant filler is different from Preparation Example 1 in that step S4 is not performed, the product in step S3 is the nano ZrO2 particles coated with aluminum hydroxide, which is the flame retardant filler, and the other steps are the same as Preparation Example 1. Example Example 1

[0047] A flame-retardant and chemical-resistant layer for airtight flame-retardant and chemical-resistant fabrics is provided. The flame-retardant filler obtained in Preparation Example 1 and modified PE, ethylene-acrylate-maleic anhydride terpolymer, copolymerized PA, and silicone polyamide elastomer, EVOH, copolymerized PA, ethylene-acrylate-maleic anhydride terpolymer, and modified PE are added to seven barrels respectively using a multi-layer co-extrusion device. The mixture is melt-coextruded, blown into a film, and then cooled and shaped to obtain an airtight flame-retardant and chemical-resistant fabric flame-retardant layer comprising, from the outside to the inside, a composite PE layer, a first TIE layer, a composite PA layer, an EVOH layer, a copolymerized PA layer, a second TIE layer, and a modified PE layer. The mass ratio of flame retardant filler to modified PE is 1:5, and the modified PE is PE-g-MAH; The mass ratio of copolymerized PA and silicone polyamide elastomer is 1:0.24; The thickness of each layer is: 15μm composite PE layer, 3μm first TIE layer, 10.5μm composite PA layer, 8μm EVOH layer, 10.5μm copolymer PA layer, 3μm second TIE layer and 15μm modified PE layer. The thickness of the flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabrics is 65μm. Example 2

[0048] A flame-retardant and chemical-proof layer for airtight flame-retardant and chemical-proof fabrics is provided. The flame-retardant filler obtained in Preparation Example 2 and modified PE, ethylene-acrylate-maleic anhydride terpolymer, copolymerized PA, and silicone polyamide elastomer, EVOH, copolymerized PA, ethylene-acrylate-maleic anhydride terpolymer, and modified PE are added to seven barrels respectively using a multi-layer co-extrusion device. The mixture is melt-coextruded, blown into a film, and then cooled and shaped to obtain an airtight flame-retardant and chemical-proof layer for airtight flame-retardant and chemical-proof fabrics, which comprises, from the outside to the inside, a composite PE layer, a first TIE layer, a composite PA layer, an EVOH layer, a copolymerized PA layer, a second TIE layer, and a modified PE layer. The mass ratio of flame retardant filler to modified PE is 1:4.6, and the modified PE is PE-g-MAH; The mass ratio of copolymerized PA and silicone polyamide elastomer is 1:0.18; The thickness of each layer is: 15μm composite PE layer, 3μm first TIE layer, 12μm composite PA layer, 9μm EVOH layer, 10μm copolymer PA layer, 3μm second TIE layer and 16μm modified PE layer. The thickness of the flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabrics is 68μm. Example 3

[0049] A flame-retardant and chemical-proof layer for airtight flame-retardant and chemical-proof fabrics is provided. The flame-retardant filler obtained in Preparation Example 3 and modified PE, ethylene-acrylate-maleic anhydride terpolymer, copolymerized PA, and silicone polyamide elastomer, EVOH, copolymerized PA, ethylene-acrylate-maleic anhydride terpolymer, and modified PE are added to seven barrels respectively using a multi-layer co-extrusion device. The mixture is melt-coextruded, blown into a film, and then cooled and shaped to obtain an airtight flame-retardant and chemical-proof layer for airtight flame-retardant and chemical-proof fabrics, which comprises, from the outside to the inside, a composite PE layer, a first TIE layer, a composite PA layer, an EVOH layer, a copolymerized PA layer, a second TIE layer, and a modified PE layer. The mass ratio of flame retardant filler to modified PE is 1:3.5, and the modified PE is PE-g-MAH; The mass ratio of copolymerized PA and silicone polyamide elastomer is 1:0.1; The thickness of each layer is: 14μm composite PE layer, 2μm first TIE layer, 10μm composite PA layer, 8μm EVOH layer, 10μm copolymer PA layer, 2μm second TIE layer and 14μm modified PE layer. The thickness of the flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabrics is 60μm. Example 4

[0050] A flame-retardant and chemical-resistant layer for airtight flame-retardant and chemical-resistant fabrics is provided. The flame-retardant filler obtained in Preparation Example 4 and modified PE, ethylene-acrylate-maleic anhydride terpolymer, copolymerized PA, and silicone polyamide elastomer, EVOH, copolymerized PA, ethylene-acrylate-maleic anhydride terpolymer, and modified PE are added to seven barrels respectively using a multi-layer co-extrusion device. The mixture is melt-coextruded, blown into a film, and then cooled and shaped to obtain an airtight flame-retardant and chemical-resistant fabric flame-retardant layer comprising, from the outside to the inside, a composite PE layer, a first TIE layer, a composite PA layer, an EVOH layer, a copolymerized PA layer, a second TIE layer, and a modified PE layer. The mass ratio of flame retardant filler to modified PE is 1:6, and the modified PE is PE-g-MAH; The mass ratio of copolymerized PA and silicone polyamide elastomer is 1:0.3; The thickness of each layer is: 16μm composite PE layer, 3μm first TIE layer, 12.5μm composite PA layer, 8μm EVOH layer, 12.5μm copolymer PA layer, 3μm second TIE layer and 15μm modified PE layer. The thickness of the flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabrics is 70μm. Example 5

[0051] A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric is provided. The difference from Example 1 is that the flame retardant filler in the composite PA layer is obtained from Preparation Example 5, and the other steps are the same as Example 1. Example 6

[0052] A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric is provided. The difference from Example 1 is that the flame retardant filler in the composite PA layer is obtained from Preparation Example 6, and the other steps are the same as Example 1. Example 7

[0053] A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric is provided. The difference from Example 1 is that the flame retardant filler in the composite PA layer is obtained from Preparation Example 7, and the other steps are the same as Example 1. Example 8

[0054] A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric is provided. The difference from Example 1 is that the flame retardant filler in the composite PA layer is obtained from Preparation Example 8, and the other steps are the same as Example 1. Example 9

[0055] A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric is provided. The difference from Example 1 is that the flame retardant filler in the composite PA layer is obtained from Preparation Example 9, and the other steps are the same as Example 1. Example 10

[0056] A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric is provided. The difference from Example 1 is that the flame retardant filler in the composite PA layer is obtained from Preparation Example 10, and the other steps are the same as those in Example 1. Example 11

[0057] A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric is provided. The difference from Example 1 is that the flame retardant filler in the composite PA layer is obtained from Preparation Example 11, and the other steps are the same as Example 1. Example 12

[0058] A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric is provided. The difference from Example 1 is that the flame retardant filler in the composite PA layer is obtained from Preparation Example 12, and the other steps are the same as Example 1. Comparative Example

[0059] Comparative Example 1 A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric, which differs from Example 1 in that no flame retardant filler is added to the composite PA layer, and the flame retardant and chemical-proof layer comprises, from the outside to the inside, a modified PE layer, a first TIE layer, a composite PA layer, an EVOH layer, a copolymerized PA layer, a second TIE layer and a modified PE layer, and the other steps are the same as in Example 1.

[0060] Comparative Example 2 A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric, which differs from Example 1 in that no silicone polyamide elastomer is added to the composite PA layer, and the flame retardant and chemical-proof layer comprises, from the outside to the inside, a composite PE layer, a first TIE layer, a copolymerized PA layer, an EVOH layer, a copolymerized PA layer, a second TIE layer, and a modified PE layer, and the other steps are the same as in Example 1.

[0061] Comparative Example 3 A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric is provided. The difference from Example 1 is that no flame retardant filler is added to the composite PA layer, and no silicone polyamide elastomer is added to the composite PA layer. The flame retardant and chemical-proof layer comprises, from the outside to the inside, a modified PE layer, a first TIE layer, a copolymerized PA layer, an EVOH layer, a copolymerized PA layer, a second TIE layer, and a modified PE layer. The other steps are the same as in Example 1.

[0062] Comparative Example 4 A flame retardant and chemical-proof layer for an airtight flame retardant and chemical-proof fabric is provided. The difference from Example 1 is that no EVOH layer is provided. The flame retardant and chemical-proof layer comprises, from the outside to the inside, a composite PE layer, a first TIE layer, a composite PA layer, a copolymerized PA layer, a second TIE layer and a modified PE layer. The other steps are the same as those in Example 1. Performance testing

[0063] The following relevant performance test was performed on the flame retardant and chemical protective layer of an airtight flame retardant and chemical protective fabric of Example 1-12 and Comparative Example 1-4. Each group of performance test was performed 3 times, and the average value of the 3 test results was taken as the final result, and the results were recorded in Table 1-2.

[0064] 1. Chemical protection: According to the relevant provisions of GB 24539-2021 "Protective Clothing - Chemical Protective Clothing" on airtight chemical protective clothing-1ET, the flame-retardant chemical protective layer is tested for its low-temperature and high-temperature resistance, permeability, and liquid pressure penetration resistance. The penetration time and pressure penetration resistance level of the flame-retardant chemical protective layer are evaluated and recorded. 2. Heat aging resistance: The heat aging resistance of the flame retardant layer is tested according to the relevant provisions of HG / T 3049-1999 on chemical protective clothing for firefighters; 3. Flame retardancy: According to the relevant provisions of GB / T 13489-1992 on chemical protective clothing for firefighters, the flame retardant performance of the flame retardant layer is tested in terms of flaming combustion, flameless combustion time and damage length.

[0065] Table 1

[0066] Table 2

[0067] According to the performance test results of Examples 1-12 in Table 1-2, it can be seen that the flame-retardant and chemical-proof layer of the 7-layer co-extruded structure adopted in the present application can maintain structural stability at high temperatures, and has excellent flame retardant and chemical-proof properties, and meets the flame retardant and chemical-proof properties of airtight chemical protective clothing and firefighter protective clothing specified in GB 24539-2021 and GB / T 13489-199. This shows that the flame-retardant and chemical-proof layer in the present application can be used to prepare airtight flame-retardant and chemical-proof fabrics, and effectively protect workers in firefighting, petrochemical, metallurgical casting, electric power and other industries who are in high temperature and chemical working environments for a long time.

[0068] According to the performance test results of Examples 1-4 and Comparative Examples 1-4, it can be seen that the EVOH layer, as the main chemical protection functional layer, plays a leading chemical protection role. Compared with the traditional sandwich structure, the flame retardant and chemical protection performance of the flame retardant and chemical protection layer is achieved by setting the PE layer, TIE layer, PA layer and EVOH layer. The flame retardant and chemical protection layer of the present application adds aluminum hydroxide-wrapped nano-ZrO2 core-shell wrapped structure particles as flame retardant fillers and is composited with modified PE as the outermost composite PE layer, which significantly improves the flame retardant performance and flexibility of the flame retardant and chemical protection layer at different temperatures, and is more durable. The copolymerized PA and silicone polyamide elastomer composite used in the present application as the composite PA layer further enhances the flame retardant and chemical protection performance and high-temperature durability of the flame retardant and chemical protection layer.

[0069] According to the performance test results of Examples 1-7 and Example 12, it can be seen that the flame-retardant filler that has not been surface-modified by a coupling agent has better flame-retardant, chemical-resistant and high-temperature resistance than the flame-retardant and chemical-resistant layer formed by compounding the flame-retardant filler modified by a coupling agent with modified PE as the outermost layer. This is because the surface modification of the flame-retardant filler particles using a titanate coupling agent effectively improves the compatibility between the flame-retardant filler and the PE matrix, resulting in stronger interfacial bonding force, which further improves the overall performance stability of the flame-retardant and chemical-resistant layer.

[0070] According to the performance results of Examples 1-7, it can be seen that when isopropyl trioleyloxy titanate is used as a coupling agent, it has the best effect on improving the various properties of the flame retardant and chemical protective layer. This may be because compared with other titanates, after titanation, the polarity retained by the carboxylic acid group of oleic acid in oleic acid titanate is more compatible with the polarity of the maleic anhydride group in PE-g-MAH; on the other hand, it may be because oleic acid titanate contains a higher content of flexible unsaturated long-chain structure. This flexible chain segment is easier to entangle with the PE matrix to enhance compatibility. At the same time, the long-chain structure can form a steric hindrance to prevent agglomeration between fillers, further improving the dispersion uniformity of the flame retardant filler in the PE matrix.

[0071] The performance test results of Examples 1-4 and 8 show that the flame-retardant layer formed by directly mixing aluminum hydroxide and nano-ZrO2 as a flame-retardant filler is significantly inferior to the flame-retardant layer formed by the core-shell structure with aluminum hydroxide as the encapsulating layer and nano-ZrO2 as the core. This may be due to the fact that when aluminum hydroxide and ZrO2 are randomly distributed in the PE matrix, phase separation may occur due to the multi-component filler. The flame retardant effects of the two components may occur simultaneously, interfering with each other's thermal responses, resulting in overlapping or conflicting functions and preventing effective synergy.

[0072] According to the performance test results of Examples 1-4 and Example 9, it can be seen that the various performances of the composite PE layer prepared with the flame-retardant filler that has not been heat-treated are reduced after forming a flame-retardant and chemical-resistant layer. This is because the core-shell wrapping structure stability of the aluminum hydroxide-wrapped nano-ZrO2 that has not been heat-treated is weaker than that of the heat-treated structure, and there are internal defects after the composite PE layer is formed, resulting in a decline in overall performance.

[0073] According to the performance test results of Examples 1-4 and 10-11, it can be seen that the composite PE layer using core-shell wrapped structure particles of aluminum hydroxide wrapped nano-ZrO2 as flame retardant fillers and composited with modified PE as the outermost layer has a more significant effect on improving the various performances of the flame retardant and chemical protective layer than using only aluminum hydroxide or nano-ZrO2. This is because the composite flame retardant filler can be more evenly dispersed in the matrix, and the flame retardant properties and temperature properties of aluminum hydroxide and nano-ZrO2 work together to achieve "staged flame retardancy" and "gradient thermal protection", which significantly improves the overall flame retardancy and thermal protection performance of the flame retardant and chemical protective layer.

[0074] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabrics, characterized in that: From the outside to the inside, it includes a composite PE layer, a first TIE layer, a composite PA layer, an EVOH layer, a copolymerized PA layer, a second TIE layer and a modified PE layer. The thickness of the flame retardant and chemical-resistant layer is 60-70 μm. The raw materials of the composite PE layer include flame retardant filler and modified PE; The mass ratio of the flame retardant filler to the modified PE is 1:(3.5-6), and the raw materials of the flame retardant filler include nano ZrO2 and aluminum hydroxide.

2. The flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabric according to claim 1, characterized in that The method for preparing the flame retardant filler comprises the following steps: S1: Disperse nano ZrO2 in water and ultrasonicate for 25-35 min to prepare a uniform zirconium source suspension of 15-20 g / L; S2: Dissolve Al(NO3)3 in water to prepare a 0.3-0.5 mol / L aluminum source solution; S3: adding the aluminum source solution to the zirconium source suspension, adding ammonia water, adjusting the pH to (9±0.2), stirring the reaction for 2-2.5 hours, collecting the precipitate by centrifugation, washing and drying, and then heat-treating at 300-450°C to obtain nano-ZrO2 particles coated with aluminum hydroxide; S4: Disperse the nano ZrO2 particles coated with aluminum hydroxide in ethanol, add a coupling agent, and react with stirring at 70-80°C for 1-1.5 hours. The concentration of the coupling agent is 3-5%. Then, collect the precipitate by centrifugation, wash and dry.

3. The flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabric according to claim 2, characterized in that The coupling agent is a titanate coupling agent, selected from any one or more combinations of isopropyl tris(dioctyl pyrophosphate acyloxy) titanate, isopropyl tris(dioctyl phosphate acyloxy) titanate, isopropyl trioleyl titanate and isopropyl tristearate titanate.

4. The flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabric according to claim 3, characterized in that , the coupling agent is isopropyl trioleate titanate.

5. The flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabric according to claim 1, characterized in that , the modified PE is PE-g-MAH.

6. The flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabric according to claim 1, characterized in that The raw materials of the composite PA layer include copolymerized PA and silicone polyamide elastomer in a mass ratio of 1:(0.1-0.3).

7. The flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabric according to claim 1, characterized in that , the raw materials of the first TIE layer and the second TIE layer include ethylene-acrylate-maleic anhydride terpolymer.

8. Use of the flame retardant and chemical protective layer for airtight flame retardant and chemical protective fabrics according to claims 1 to 7 in the preparation of airtight flame retardant and chemical protective fabrics.

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