High-flame-retardant PU skin material for high-speed rail seats and preparation method thereof
By introducing modified MXene and phosphorus-containing diol chain extenders into the PU surface material for high-speed rail seats, a dense carbon layer structure is formed, which solves the problem of the physical properties of the PU surface material decreasing when the flame retardancy is improved. This achieves a balance between high-efficiency flame retardancy and mechanical properties, meeting the multiple performance standards of high-speed rail seats.
Patent Information
- Application Number
- CN202510676179.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-24
- Publication Date
- 2025-09-19
AI Technical Summary
When improving the flame retardancy of existing PU surface materials used in high-speed rail seats, physical properties such as tensile strength, tear strength and flexibility are usually sacrificed, making it difficult to simultaneously meet the multiple standards of flame retardancy, wear resistance, environmental protection and comfort.
Modified MXene is used as a filler, combined with a phosphorus-containing diol chain extender and a surface coating. By forming a dense flame-retardant and thermal insulation barrier and a carbon layer structure in the PU matrix, the water-based treatment agent is modified with silicon PUD to form a dense carbon layer structure, which improves the flame retardancy and thermal insulation properties while maintaining good mechanical properties.
The PU surface material achieves efficient flame retardancy in a combustion environment, maintains the mechanical properties and comfort of the material, reduces production costs, and meets the multiple performance requirements of high-speed rail seats.
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Abstract
Description
Technical Field
[0001] The present application relates to the technical field of synthetic leather, and more specifically, to a highly flame-retardant PU surface material for high-speed rail seats and a preparation method thereof. Background Art
[0002] PU surface material, also known as PU synthetic leather, is an ideal substitute for natural leather after PVC synthetic leather. It not only has a texture and soft feel similar to genuine leather, but also has a variety of aesthetic expressions. PU resin is usually coated on a substrate to prepare a PU surface material that is wear-resistant, fold-resistant, weather-resistant, anti-aging and beautiful. It is used in the outer protection of high-speed rail seats.
[0003] However, PU material itself is a flammable polymer material. When it burns, it will not only spread the fire rapidly, increasing the risk of fire, but also release highly toxic gases such as carbon monoxide and cyanide, which seriously threaten the safety of people and the environment. With the rapid development of high-speed railway technology and the tightening of fire safety regulations, the speed and passenger capacity of trains have increased significantly, and the performance requirements for high-speed rail seat materials have become increasingly stringent. As the core component that passengers directly contact, the surface material of high-speed rail seats must meet multiple standards such as flame retardancy, wear resistance, environmental protection and comfort.
[0004] In the existing technology, a large amount of flame retardants, such as halogen, phosphorus, magnesium hydroxide, etc., are usually added, or flame retardant coatings are applied through surface coating technology to improve the flame retardancy of PU surface materials. However, with respect to the above-mentioned related technologies, the inventors found that the use of traditional flame retardants often sacrifices the physical properties of PU surface materials, such as reducing tensile strength, tear strength and flexibility, to improve flame retardancy, which limits the application of PU surface materials. Summary of the Invention
[0005] In order to improve the flame retardancy of PU surface materials for high-speed rail seats and at the same time ensure that the PU surface materials have good physical properties, the present application provides a highly flame retardant PU surface material for high-speed rail seats and a preparation method thereof.
[0006] In the first aspect, the present application provides a highly flame-retardant PU surface material for high-speed rail seats, adopting the following technical solution: a highly flame-retardant PU surface material for high-speed rail seats, comprising a base fabric layer, a PU surface layer and a surface coating in sequence. The raw materials of the PU surface layer include, in parts by weight, 41-63 parts of isocyanate, 89-107 parts of polyether polyol, 5.5-7.3 parts of diol chain extender, 0.05-0.1 parts of organic tin catalyst, 9-15 parts of modified MXene, 1-2 parts of defoaming agent, 0.4-0.7 parts of dispersant and 0.3-0.7 parts of leveling agent.
[0007] By adopting the above technical solution, the modified MXene used as a filler enhances the dispersion uniformity of MXene in the PU matrix, and can be evenly arranged during combustion, effectively forming a dense flame-retardant and heat-insulating barrier, inhibiting the diffusion of heat and oxygen, and enhancing the flame retardancy of the PU surface material while improving the mechanical properties of the PU surface material. The lamellar structure of MXene effectively blocks the transfer of combustion heat to the inner base fabric layer, thereby improving the thermal insulation performance of the PU surface material.
[0008] Optionally, the diol chain extender is a bisphenol A type phosphorus-containing diol.
[0009] By adopting the above technical solution, the use of phosphorus-containing diol chain extender introduces phosphorus element into the PU molecular chain, thereby improving the intrinsic flame retardancy of the PU matrix, further reducing the dependence on flame-retardant fillers, and reducing the influence of fillers on the mechanical properties of the PU surface layer. The rigid benzene ring structure of bisphenol A-type phosphorus-containing diol is embedded in the PU molecular chain, taking into account both flame retardancy and rigid chain segment construction, which helps to improve the mechanical strength of the PU matrix and can form a skeleton support for the carbon layer during combustion, thereby preventing the collapse of the carbon layer, while reducing the sacrifice of material elasticity, and can also enhance the high thermal stability of the PU matrix and delay the oxidative decomposition of the carbon layer at high temperature.
[0010] Optionally, the preparation method of the modified MXene comprises the following steps: MXene was surface treated in H2O2 solution, centrifuged, washed and dried, and then added into phytic acid solution and ultrasonicated to obtain a mixed solution; FeCl3·6H2O is added to the mixed solution, stirred for reaction, centrifuged, washed and dried to obtain the modified MXene.
[0011] By adopting the above technical solution, the surface oxidation treatment of H2O2 solution introduces oxygen-containing functional groups on the surface of MXene, which enhances the compatibility between MXene and PU matrix, improves the dispersion uniformity of MXene in PU matrix, helps to form a continuous flame retardant and thermal insulation barrier, and promotes the use of MXene as a carrier for the polymerization of phytic acid and Fe 3+ load capacity.
[0012] Phytic acid and Fe 3+ It can chelate to form a metal-phytic acid complex. When the complex is burned, it further decomposes to form iron oxide as a catalyst. The chelation of phytic acid delays the Fe 3+ The oxidation failure of the carbonization reaction during combustion is reduced, thereby extending the catalytic time of the carbonization reaction during combustion, improving the graphitization degree of the carbon layer, and forming a dense carbon layer. On the other hand, it releases non-combustible gases such as CO2 and H2O, diluting the concentration of combustible gases (such as hydrocarbons and CO), effectively inhibiting the combustion chain reaction, inhibiting the spread of flames, and also improving the heat radiation barrier performance of the PU surface layer.
[0013] Optionally, the concentration of phytic acid in the mixture is 0.03-0.05 mol / L, Fe 3+ The concentration is 0.04-0.06mol / L.
[0014] Optionally, the surface coating is made of a surface coating, and the raw materials of the surface coating include 40-60 parts of silicon PUD modified water-based treatment agent, 5-7 parts of chitosan, 4-6 parts of curing agent and 4-6 parts of flame retardant, based on parts by weight.
[0015] Optionally, the flame retardant is ammonium polyphosphate.
[0016] By adopting the above technical solution, using a silicon PUD modified water-based treatment agent as the outer coating matrix is more environmentally friendly. Ammonium polyphosphate is used as an intumescent flame retardant, which can decompose into polyphosphoric acid and ammonia at high temperature. Chitosan is used as a carbon source to synergistically react with the ammonium polyphosphate flame retardant to form an outer intumescent cross-linked carbon layer with a PN structure, which isolates oxygen and heat. The ammonia, water vapor and other gases formed by decomposition dilute the concentration of combustible gases, and the flame retardant properties of the PU surface material are synergistically enhanced through the gas phase and the condensed phase.
[0017] In a second aspect, the present application provides a method for preparing a highly flame-retardant PU surface material for high-speed rail seats, using the following technical solution: A method for preparing a highly flame-retardant PU surface material for high-speed rail seats comprises the following steps: S1: Prepare the raw materials according to the weight of the formula, add polyether polyol, phosphorus-containing diol chain extender and organotin catalyst into a nitrogen-protected reactor, mix, heat and stir to react, then add isocyanate and continue the reaction to obtain a PU prepolymer; S2: Add modified MXene, defoamer, dispersant and leveling agent to the PU prepolymer and continue stirring to react until the viscosity reaches 7000-8000 mPa·s / 25°C. Then, cool the material to obtain a slurry, apply the slurry to the surface of the release paper, and dry it to obtain the PU surface layer; S3: After laminating the PU surface layer and the base fabric layer, peeling off the release paper to obtain a prefabricated PU surface material; S4: preparing a surface coating, applying the surface coating to the side of the PU surface layer away from the base fabric layer in the prefabricated PU surface material in the form of roller coating, and forming a surface coating after drying.
[0018] By adopting the above technical solution, PU surface materials are prepared using water-based surface coatings and halogen-free flame retardant systems, while taking into account both environmental friendliness and the long-term durability of the materials, ensuring the uniformity of filler dispersion in the PU matrix and surface coating, and improving the flame retardancy of the PU surface materials while ensuring that the PU surface materials have excellent mechanical properties.
[0019] Optionally, the thickness of the PU surface layer is (0.15±0.03) mm.
[0020] Optionally, the thickness of the surface coating is (0.1±0.03) mm.
[0021] By adopting the above technical solution, a better flame retardant effect can be achieved with a thinner surface layer. The thinner surface layer can also provide a softer feel and better touch, while reducing the weight of the material and lowering the production cost.
[0022] In summary, this application has the following beneficial effects: 1. This application designs the raw material formula of PU surface layer and surface coating to achieve the hierarchical carbon layer structure of PU surface material under combustion environment. The ammonium polyphosphate and chitosan in the surface coating form an expanded porous carbon layer on the surface to reflect radiant heat. The PU surface layer is loaded with phytic acid and Fe by MXene. 3+ The system catalyzes the carbonization reaction of the outer layer and the formation of a continuous and dense cross-linked carbon layer on the phosphorus-containing PU matrix under a combustion environment, significantly enhancing the flame retardant stability of the PU surface material.
[0023] 2. In this application, surface-treated MXene loaded with phytic acid and Fe is preferred. 3+ The method of obtaining modified MXene not only achieves the catalytic effect on the flame retardant carbonization reaction, but also promotes the uniform dispersion of MXene in the PU matrix, so that the PU surface material can maintain good mechanical properties. At the same time, the lamellar structure of the modified MXene delays the transfer of heat to the base fabric layer, acts as a barrier to heat, and improves the thermal insulation of the PU surface fabric.
[0024] 3. The PU surface material prepared by the method of the present application has a PU surface layer thickness of (0.15±0.03) mm and a surface coating thickness of (0.1±0.03) mm, which can achieve an efficient flame retardant effect. The thinner surface layer achieves a softer feel and better touch, while reducing the weight of the material and the production cost. It can meet multiple standards of flame retardancy, wear resistance, environmental protection and comfort of PU surface materials for high-speed rail seats. DETAILED DESCRIPTION
[0025] The following examples further illustrate the present application in detail.
[0026] raw material Unless otherwise specified, the raw materials used in the preparation examples, examples and comparative examples in this application are all commercially available products, specifically: The base fabric is polyester spunbond non-woven fabric with a thickness of (0.9±0.05) mm and a weight of 70 g / m 2 ; Defoaming agent, which is a silicone defoaming agent, selected from Dongguan Defeng Defoaming Agent Co., Ltd., DF-2854; Dispersant, selected from BASF, Efka PU 4010; Leveling agent, which is an organic silicone leveling agent, selected from Guangzhou Dachuan Fine Chemical Co., Ltd., BYK-301; MXene, with a thickness of 100-150 nm and a flake diameter of 2-8 μm; Silicone PUD modified water-based treatment agent, selected from Siluoke, Dolphin1430T silicon-modified self-crosslinking PUD emulsion; Chitosan, carboxymethyl chitosan, CAS: 83512-85-0; The curing agent is a static aziridine curing agent selected from Ammonium polyphosphate, selected from Shifang Changfeng Chemical Co., Ltd., ammonium polyphosphate type I; Polytetramethylenetetrahydrofuran diol, selected from Hyosung Chemical Co., Ltd., with an average molecular weight of 2000; Water-based PU adhesive, selected from Anhui Dawei Huatai New Material Technology Co., Ltd., AH-1802A; Cross-linking agent, selected from Wanhua Chemical Group Co., Ltd., HT-100; The release paper is TPX type release paper, brand DX820.
[0027] Preparation example of modified MXene Preparation Example 1 Modified MXene and its preparation method include the following steps: S1: MXene was added to deionized water at a material-liquid ratio of 1:80, and ultrasonically dispersed for 40 min to obtain a MXene dispersion. A 5 wt% H2O2 solution was added to the MXene dispersion to make the mass ratio of MXene to H2O2 1:10. The surface was oxidized by magnetic stirring for 2.5 h, and the pretreated MXene was obtained after centrifugation, washing, and freeze-drying. S2: 0.1 g of pretreated MXene was added to 250 mL of phytic acid solution and ultrasonicated for 30 min to obtain a mixed solution, wherein the concentration of phytic acid was 0.03 mol / L; S2: Add FeCl3·6H2O to the mixture, Fe 3+ The concentration of MXene was 0.04 mol / L, and the mixture was stirred for 2 h before centrifugation, washing, and freeze-drying to obtain the modified MXene.
[0028] Preparation Example 2 Modified MXene and its preparation method include the following steps: S1: MXene was added to deionized water at a material-liquid ratio of 1:80, and ultrasonically dispersed for 40 min to obtain a MXene dispersion. A 5 wt% H2O2 solution was added to the MXene dispersion to make the mass ratio of MXene to H2O2 1:10. The surface was oxidized by magnetic stirring for 2.5 h, and the pretreated MXene was obtained after centrifugation, washing, and freeze-drying. S2: 0.1 g of pretreated MXene was added to 250 mL of phytic acid solution and ultrasonicated for 35 min to obtain a mixed solution, wherein the concentration of phytic acid was 0.04 mol / L; S2: Add FeCl3·6H2O to the mixture, Fe 3+ The concentration of MXene was 0.05 mol / L, and the mixture was stirred for 2.5 h before centrifugation, washing, and freeze-drying to obtain the modified MXene.
[0029] Preparation Example 3 Modified MXene and its preparation method include the following steps: S1: MXene was added to deionized water at a material-liquid ratio of 1:80, and ultrasonically dispersed for 40 min to obtain a MXene dispersion. A 5 wt% H2O2 solution was added to the MXene dispersion to make the mass ratio of MXene to H2O2 1:10. The surface was oxidized by magnetic stirring for 2.5 h, and the pretreated MXene was obtained after centrifugation, washing, and freeze-drying. S2: 0.1 g of pretreated MXene was added to 250 mL of phytic acid solution and ultrasonicated for 30 min to obtain a mixed solution, wherein the concentration of phytic acid was 0.05 mol / L; S2: Add FeCl3·6H2O to the mixture, Fe 3+ The concentration of MXene was 0.06 mol / L, and the mixture was stirred for 3 h before centrifugation, washing, and freeze-drying to obtain the modified MXene.
[0030] Preparation Example 4 Modified MXene and its preparation method include the following steps: MXene was added to deionized water at a material-liquid ratio of 1:80, and ultrasonic dispersion was performed for 40 minutes to obtain a MXene dispersion. A 5 wt% H2O2 solution was added to the MXene dispersion to make the mass ratio of MXene to H2O2 1:10. The surface oxidation treatment was carried out by magnetic stirring for 2.5 hours, and the mixture was obtained after centrifugation, washing, and freeze-drying. Example
[0031] Example 1 A highly flame-retardant PU surface material for high-speed rail seats comprises, in sequence, a base fabric layer, a PU surface layer, and a surface coating. The raw materials for the PU surface layer are shown in Table 1, wherein the isocyanate is diphenylmethane diisocyanate and isophorone diisocyanate in a mass ratio of 1:1.5, the polyether polyol is polytetramethylene glycol, the organotin catalyst is stannous octoate, the diol chain extender is bisphenol A-type phosphorus-containing diol, and the modified MXene is obtained according to Preparation Example 1. The raw materials for the surface coating are shown in Table 2, wherein the flame retardant is ammonium polyphosphate.
[0032] Table 1 Table 2 The method for preparing the highly flame-retardant PU surface material for high-speed rail seats comprises the following steps: S1: Under a nitrogen atmosphere, bisphenol A and phenylphosphonyl dichloride were mixed in a molar ratio of 2:1 and dissolved in tetrahydrofuran. The mixture was heated to 100° C. and reacted for 12 h until the phenolic hydroxyl groups were completely phosphorylated to obtain a reactant. The reactant was cooled and added to ethylene glycol. The pH of the system was adjusted to 7. The temperature was raised to 60° C. and stirred for 2.5 h. The solvent was removed by distillation under reduced pressure, the mixture was cooled and crystallized, and filtered and dried to obtain bisphenol A type phosphorus-containing diol. S2: Prepare the raw materials according to the weight of the formula, add the polyether polyol, phosphorus-containing diol chain extender and organotin catalyst into a nitrogen-protected reactor, mix and heat to 85° C., stir and react for 1.5 hours, then add isocyanate and continue to react for 2.5 hours to obtain a PU prepolymer; S3: Add modified MXene, defoamer, dispersant and leveling agent to the PU prepolymer, continue stirring and reacting until the system viscosity reaches 7000mPa·s / 25℃, then discharge the material and cool it to obtain a slurry. Use a coating machine to control the speed to 12m / min and coat the slurry on the surface of the release paper with a coating thickness of (0.15±0.03)mm. Then place it in an oven and heat and dry it by gradient heating at 70, 80, 100, 110 and 125℃, respectively. The drying time is 4min in total to form a PU surface layer on the release paper. S4: Mixing a water-based PU adhesive and a cross-linking agent in a mass ratio of 90:1 to form an adhesive, coating the adhesive on the surface of the base fabric layer, heating and pre-curing to obtain a semi-cured base fabric layer, laminating the side of the PU surface layer away from the release paper with the semi-cured base fabric layer, and peeling off the release paper after curing to obtain a prefabricated PU surface material; S5: The silicon PUD modified water-based treatment agent, chitosan, curing agent and flame retardant are mixed and stirred evenly to form a surface coating, and the surface coating is applied to the side of the PU surface layer away from the base fabric layer in the prefabricated PU surface material in the form of roller coating at a processing speed of 10m / min. The coating thickness is (0.1±0.03)mm, and the surface coating is formed after drying.
[0033] Example 2 A PU surface material is different from Example 1 in that the raw materials of the PU surface layer are shown in Table 1, wherein the modified MXene is obtained by Preparation Example 2, the raw materials of the surface coating are shown in Table 2, and the material is discharged when the system viscosity in step S3 is 8000 mPa·s / 25°C. The other steps are the same as in Example 1.
[0034] Example 3 A PU surface material is different from Example 1 in that the raw materials of the PU surface layer are shown in Table 1, wherein the modified MXene is obtained by Preparation Example 3, the raw materials of the surface coating are shown in Table 2, and the material is discharged when the system viscosity in step S3 is 7800 mPa·s / 25°C. The other steps are the same as in Example 1.
[0035] Example 4 A PU surface material is different from Example 1 in that the raw materials of the PU surface layer are shown in Table 1, the raw materials of the surface coating are shown in Table 2, the material is discharged when the system viscosity is 7400 mPa·s / 25°C in step S3, and the other steps are the same as Example 1.
[0036] Example 5 A PU surface material is different from Example 1 in that the modified MXene in the raw material of the PU surface layer is obtained from Preparation Example 4, and the other steps are the same as Example 1.
[0037] Example 6 A PU surface material is different from Example 1 in that chitosan is not used, and the chitosan in the surface coating raw material is replaced by an equal mass of silicon PUD modified water-based treatment agent, and the other steps are the same as Example 1.
[0038] Example 7 A PU surface material is different from Example 1 in that the flame retardant in the surface coating raw material is aluminum hydroxide, and the other steps are the same as Example 1.
[0039] Example 8 A PU surface material, which differs from Example 1 in that chitosan and flame retardant are not used, and the chitosan and flame retardant in the surface coating raw materials are replaced by an equal mass of silicon PUD modified water-based treatment agent, and the other steps are the same as Example 1.
[0040] Example 9 A PU surface material is different from Example 1 in that the preparation process of bisphenol A type phosphorus-containing diol in step S1 is not performed, the diol chain extender in the PU surface layer raw material is 1,3-propylene glycol, and the other steps are the same as Example 1.
[0041] Comparative Example Comparative Example 1 A PU surface material, which differs from Example 1 in that modified MXene is not added to the PU surface layer, and other steps are the same as Example 1.
[0042] Comparative Example 2 A PU surface material, which differs from Example 9 in that modified MXene is not added to the PU surface layer, and the other steps are the same as Example 9.
[0043] Performance testing The following relevant performance test tests were performed on the PU surface materials obtained in Examples 1-9 and Comparative Examples 1-2. Each test was performed 3 times, and the average value of the 3 test results was taken as the final result and the final result was recorded in Table 3.
[0044] 1. Flame retardancy: The PU surface materials obtained in Examples 1-9 and Comparative Examples 1-2 were subjected to a flame retardancy test according to the relevant provisions of GB 8410-2006. Flame retardancy of ≤65 mm / min was designated as A, flame retardancy of 65-80 mm / min was designated as B, and flame retardancy of ≥80 mm / min was designated as C. 2. Limiting Oxygen Index: The limiting oxygen index (LOI) of the PU skin materials obtained in Examples 1-9 and Comparative Examples 1-2 was measured using an HC-2C oxygen index tester produced by Nanjing Shangyuan Analytical Instrument Co., Ltd. in accordance with the relevant provisions of GB 38262-2019. 3. Tensile Strength: The tensile strength of the PU skin materials obtained in Examples 1-9 and Comparative Examples 1-2 was measured in accordance with the relevant provisions of QB / T 1646-2007. 4. Tear strength: The tear strength of the PU skin materials obtained in Examples 1-9 and Comparative Examples 1-2 was measured with reference to the relevant provisions of ISO 34-1 standard.
[0045] Table 3 According to the performance test data in Table 3, it can be seen that the high flame retardant PU surface material for high-speed rail seats of the present application can meet the flame retardancy requirements of GB 8410-2006 for synthetic leather materials, and the limiting oxygen index reaches 27.7-32.5%. At the same time, the tensile strength and tear strength of the high flame retardant PU surface material for high-speed rail seats of the present application can also meet the mechanical strength requirements of QB / T 1646-2007 and ISO 34-1 for PU synthetic leather materials. This shows that the high flame retardant PU surface material for high-speed rail seats of the present application can significantly improve its own flame retardancy while improving its own mechanical strength and is not affected by fillers, and can meet the high requirements for flame retardancy in the application field of synthetic leather for high-speed rail seats.
[0046] According to the performance test results of Examples 1-4, Example 5 and Comparative Example 1, it can be seen that the PU surface layer is loaded with phytic acid and Fe by MXene. 3+ The system significantly enhances the flame retardant stability of the PU surface material while ensuring the mechanical properties of the material.
[0047] Phytic acid and Fe 3+ It can chelate to form a metal-phytic acid complex and load it on MXene to form a modified MXene. On the one hand, it can catalyze the flame retardant carbonization reaction. This is because the complex can decompose to form an iron oxide catalyst during combustion. First, it promotes the carbonization reaction of the surface coating during combustion, forming an expanded porous carbon layer on the outer layer, and then catalyzes the carbonization reaction of the phosphorus-containing PU surface layer, thereby increasing the graphitization degree of the carbon layer and forming a dense carbon layer. It realizes the hierarchical carbon layer structure of the PU surface material under the combustion environment, and at the same time can release non-combustible gases such as CO2 and H2O, dilute the concentration of combustible gases (such as hydrocarbons, CO), effectively inhibit the combustion chain reaction, and inhibit the spread of flames. On the other hand, MXene loaded with phytic acid and Fe 3+ The system promotes the uniform dispersion of MXene in the PU matrix, allowing the PU skin material to maintain good mechanical properties.
[0048] Performance test results from Examples 1, 9, and Comparative Example 2 indicate that the use of a phosphorus-containing diol chain extender further enhances the material's flame retardancy and increases its limiting oxygen index. This is due to the introduction of phosphorus into the PU molecular chain by the bisphenol A-type phosphorus-containing diol, which improves the intrinsic flame retardancy of the PU matrix, reduces reliance on flame-retardant fillers, and further mitigates the filler's impact on the mechanical properties of the PU surface layer. The rigid benzene ring structure of the bisphenol A-type phosphorus-containing diol is embedded within the PU molecular chain, achieving both flame retardancy and rigid chain segment construction. This enhances the mechanical strength of the PU matrix and provides skeletal support for the char layer during combustion, preventing collapse and minimizing the compromise of mechanical properties.
[0049] According to the performance test results of Examples 1 and 6-8, it can be seen that using a silicon PUD-modified water-based treatment agent as the outer coating matrix is more environmentally friendly, and ammonium polyphosphate as an intumescent flame retardant has better compatibility with the matrix than traditional aluminum hydroxide flame retardants, and can decompose at high temperatures to generate polyphosphoric acid and ammonia. Chitosan as a carbon source synergistically reacts with the ammonium polyphosphate flame retardant to form an outer intumescent cross-linked carbon layer with a PN structure, which isolates oxygen and heat. The ammonia, water vapor and other gases formed by decomposition dilute the concentration of the combustible gas, and the flame retardant properties of the PU surface material are synergistically enhanced through the gas phase and the condensed phase.
[0050] 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 highly flame-retardant PU surface material for high-speed rail seats, characterized in that: It includes a base fabric layer, a PU surface layer and a surface coating in sequence. The raw materials of the PU surface layer include, by weight, 41-63 parts of isocyanate, 89-107 parts of polyether polyol, 5.5-7.3 parts of diol chain extender, 0.05-0.1 parts of organic tin catalyst, 9-15 parts of modified MXene, 1-2 parts of defoamer, 0.4-0.7 parts of dispersant and 0.3-0.7 parts of leveling agent.
2. The highly flame-retardant PU surface material for high-speed rail seats according to claim 1, characterized in that: The diol chain extender is bisphenol A type phosphorus-containing diol.
3. The highly flame-retardant PU surface material for high-speed rail seats according to claim 1, characterized in that: The preparation method of the modified MXene comprises the following steps: MXene was surface treated in H2O2 solution, centrifuged, washed and dried, and then added into phytic acid solution and ultrasonicated to obtain a mixed solution; FeCl3·6H2O is added to the mixed solution, stirred for reaction, centrifuged, washed and dried to obtain the modified MXene.
4. The highly flame-retardant PU surface material for high-speed rail seats according to claim 3, characterized in that: The concentration of phytic acid in the mixture is 0.03-0.05 mol / L, Fe 3+ The concentration is 0.04-0.06mol / L.
5. The highly flame-retardant PU surface material for high-speed rail seats according to claim 1, characterized in that: In parts by weight, the surface coating is made of a surface coating, and the raw materials of the surface coating include 40-60 parts of a silicon PUD modified water-based treatment agent, 5-7 parts of chitosan, 4-6 parts of a curing agent and 4-6 parts of a flame retardant.
6. The highly flame-retardant PU surface material for high-speed rail seats according to claim 5, characterized in that: The flame retardant is ammonium polyphosphate.
7. The method for preparing a highly flame-retardant PU surface material for high-speed rail seats according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: Prepare the raw materials according to the weight of the formula, add polyether polyol, phosphorus-containing diol chain extender and organotin catalyst into a nitrogen-protected reactor, mix, heat and stir to react, then add isocyanate and continue the reaction to obtain a PU prepolymer; S2: Add modified MXene, defoamer, dispersant and leveling agent to the PU prepolymer and continue stirring to react until the viscosity reaches 7000-8000 mPa·s / 25°C. Then, cool the material to obtain a slurry, apply the slurry to the surface of the release paper, and dry it to obtain the PU surface layer; S3: After laminating the PU surface layer and the base fabric layer, peeling off the release paper to obtain a prefabricated PU surface material; S4: preparing a surface coating, applying the surface coating to the side of the PU surface layer away from the base fabric layer in the prefabricated PU surface material in the form of roller coating, and forming a surface coating after drying.
8. The method for preparing a highly flame-retardant PU surface material for high-speed rail seats according to claim 7, characterized in that: The thickness of the PU surface layer is (0.15±0.03) mm.
9. The method for preparing a highly flame-retardant PU surface material for high-speed rail seats according to claim 7, characterized in that: The thickness of the surface coating is (0.1±0.03) mm.