High flame retardant waterborne polyurethane, preparation method and application thereof

Abstract

The application discloses a kind of high flame-retardant performance water-based polyurethane and preparation method and application, belong to high polymer material technical field, including: polyurethane molecular chain contain specific temperature can occur aromatic ring reaction trigger crosslinking carbon structure of enediyne;The introduction amount of enediyne structure active monomer is 1-10 wt%.The application innovatively proposes only by introducing the functional monomer containing enediyne structure into polyurethane molecular chain, specific temperature triggers aromatic ring reaction to occur, realizes self-crosslinking and carbonization, and the new strategy of "intelligent" flame retardant with excellent flame retardancy and anti-dripping performance, environment-friendly, suitable for high-end fireproof field.The application does not need to add traditional flame-retardant element, and is expected to truly realize the unity of environmental protection and high performance, provides efficient solution for designing new intelligent flame-retardant high polymer material.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and particularly to a high-flame-retardant waterborne polyurethane, its preparation method, and its applications. This waterborne polyurethane material possesses intrinsic flame-retardant and anti-dripping properties. More specifically, this invention introduces enediyne structural units capable of undergoing aromatic cyclization reactions into the waterborne polyurethane molecular chain, triggering self-crosslinking at a specific temperature to form a dense char layer, thereby achieving highly efficient flame retardancy and inhibiting dripping, while maintaining the material's excellent mechanical properties and environmental characteristics. Background Technology

[0002] Waterborne polyurethane (WPU) uses water as the dispersion medium and has advantages such as being non-toxic, environmentally friendly, and easy to process, making it widely used in coatings, adhesives, textile coatings, and leather finishing. However, like most polymer materials, WPU is highly flammable and produces severe dripping during combustion, which greatly limits its application in fields with extremely high safety requirements, such as electronic packaging, new energy vehicle interiors, and building fire protection.

[0003] For flame retardant polyurethane, the most effective method is modification by introducing flame-retardant elements. Common flame-retardant elements include phosphorus, nitrogen, and silicon, which can be achieved through two methods: blending with flame retardants or copolymerizing polyurethane with reactive flame retardants. Blending flame retardant modification involves directly blending flame retardants into the polymer system. This method is simple, low-cost, and does not alter the polymer production process. Numerous studies have reported on flame retardants in this area. However, due to poor compatibility between flame retardants and the polymer matrix, they are prone to precipitating and migrating to the material surface, causing significant damage to the mechanical properties of the modified material and reducing the durability of its flame-retardant performance. Furthermore, the precipitation of some flame retardants can have harmful effects on humans and the environment.

[0004] Introducing reactive monomers containing flame-retardant elements into the polyurethane molecular chain through chemical bonding is considered an effective flame-retardant method for polymers. This method can avoid the problems of poor compatibility and migration frosting between flame retardants and polymer matrices, which lead to a decline in processing, flame retardancy, and mechanical properties. Furthermore, the synthesized flame-retardant polymers have the advantages of high flame retardant efficiency and strong durability. Professor Fan Haojun's research group at Sichuan University synthesized a series of side-chain phosphorus-containing aminophosphate diols / diamine chain extenders to prepare flame-retardant waterborne polyurethane materials, achieving excellent flame-retardant effects (1. Zhang PK, He YZ, Tian SQ, Fan HJ, Chen Y and Yan J, Flame Retardancy, Mechanical, and Thermal Properties of Waterborne Polyurethane Conjugated With a Novel Phosphorous-Nitrogen Intumescent Flame Retardant, Polymer Composites, 2015, DOI10.1002 / pc.23603; 2. Zhang PK, Tian SQ, Fan HJ, Chen Y and Yan J, Flame retardancy and hydrolysis resistance of waterborne polyurethane bearing organophosphate moieties lateral chain, Progress in Organic Coatings, 2015, 89: 170-180). Professor Luo Yunjun's research group at Beijing Institute of Technology synthesized a phosphorus-containing chain extender of bis(4-aminophenol phenyl)phenylphosphine oxide diamine to prepare waterborne polyurethane. When the chain extension ratio was 100%, the limiting oxygen index reached 30.1%, and the peak heat release rate and total heat release decreased by 57.1% and 41.6%, respectively.(Wu G, Li JQ and Luo YJ, Flame retardancy and thermal degradation mechanism of a novel post-chain extension flame retardant waterborne polyurethane, PolymerDegradation and Stability, 2016, 123: 36-46.) Reactive flame retardants can improve compatibility and durability, but current mainstream phosphorus-based flame retardants mainly function through "gas-phase flame retardancy" and "melting droplet heat-carrying" mechanisms, i.e., promoting material melting and carrying away heat. This, in turn, exacerbates the risk of molten droplets, creating a global problem of "the contradiction between flame retardancy and resistance to molten droplets." Furthermore, some phosphorus-based flame retardants may produce toxic fumes during combustion, posing potential hazards to the environment and health, and failing to meet environmental protection requirements.

[0005] Therefore, developing a novel waterborne polyurethane material that does not rely on phosphorus, fundamentally solves the contradiction between flame retardancy and drip resistance, and is environmentally friendly has become an urgent technical problem to be solved in this field. The enediyne structure can generate aryl diradicals under thermal or photo-triggered conditions, which then undergo intramolecular cyclization reactions to generate polyaromatics, ultimately forming a stable polyaromatic structure or cross-linked network. This reaction has been applied in fields such as carbon-rich materials. However, to date, there have been no reports of introducing the aryl cyclization-reactive enediyne structure into the molecular design of waterborne polyurethanes to achieve high-temperature triggered self-crosslinking and simultaneously achieve flame retardancy and drip resistance.

[0006] To address the aforementioned problems and / or defects, this invention is based on the concept of copolymer flame retardancy. It utilizes the high-temperature self-crosslinking properties of functional groups to achieve "triggered" char formation under specific conditions, thereby realizing the high flame retardant performance of waterborne polyurethane. Summary of the Invention

[0007] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0008] The purpose of this invention is to overcome the shortcomings of existing technologies, such as the difficulty in achieving both flame retardancy and anti-dripping properties in waterborne polyurethanes and the potential environmental problems caused by reliance on phosphorus-based flame retardants. Utilizing the copolymerization flame retardant concept of self-crosslinking of enediyne structures at specific temperatures, this invention discloses a waterborne polyurethane with high flame retardant performance. The molecular chain of this waterborne polyurethane contains an enediyne structure that undergoes an aromatic cyclization reaction at a specific temperature, triggering crosslinking to form carbon. The content of the enediyne structure is 1%-10wt%.

[0009] Preferably, the enediyne structure undergoes cross-linking at 160-200°C to form an aromatic structure, which matches the processing temperature range of polyurethane.

[0010] Preferably, the enediyne structure is introduced into the hard and soft segments of the polyurethane by means of an active monomer as a chain extender or end capping agent.

[0011] Preferably, the active monomer has any one of the general structural formulas I, II, III, and IV; Among them, general formula I is: HO-R1-C≡C-R2-C≡C-R1-OH; General formula II is: H2N-R3-NH-C≡C-R2-C≡C-NH-R3-NH2; General formula III is: HO-R1-C≡C-R2-C≡C; General formula IV is: H2N-R3-C≡C-R2-C≡C; Wherein, R1 is a C2-C6 alkylene or oxyalkylene; R2 is a benzene ring, naphthalene ring, or C2-C4 olefin segment; and R3 is a C2-C6 alkylene.

[0012] This invention also provides a method for preparing the high flame-retardant waterborne polyurethane as described above, comprising the following steps: Step 1: Synthesize active monomers containing enediyne structures: Take any active monomer of general formula I, general formula II, general formula III, or general formula IV and prepare diol or diamine monomers by Sonogashira coupling reaction; Step 2, Preparation of prepolymer: Under inert gas protection, the polymer polyol and diisocyanate are reacted at 60-90℃ for 1-3 hours; Step 3: Chain extension to introduce functional units: Add active monomers containing enediyne structures and / or other small molecule chain extenders to the prepolymer obtained in Step 2, and continue the reaction for 1-2 hours; Step 4, hydrophilic chain extension and neutralization: Add a chain extender containing a hydrophilic group to the reaction in Step 3 and react, then add a neutralizing agent to neutralize and generate a carboxylate; Step 5, Emulsification: Under high shear stirring, deionized water is added to the reaction system of step 4 for emulsification to obtain an aqueous polyurethane dispersion; Step 6: Post-treatment: Coat the waterborne polyurethane dispersion into a film.

[0013] Preferably, the general formula I is: HO-R1-C≡C-R2-C≡C-R1-OH; General formula II is: H2N-R3-NH-C≡C-R2-C≡C-NH-R3-NH2; General formula III is: HO-R1-C≡C-R2-C≡C; General formula IV is: H2N-R3-C≡C-R2-C≡C; Wherein, R1 is a C2-C6 alkylene or oxyalkylene; R2 is a benzene ring, naphthalene ring, or C2-C4 olefin segment; and R3 is a C2-C6 alkylene.

[0014] Preferably, the diisocyanate is any one of isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), or diphenylmethane diisocyanate (MDI); The polymer polyol is one or more of the following: dihydroxyl-terminated poly(p-dioxanone), polycaprolactone diol (PCL), polyethylene glycol (PEG), polypropylene glycol (PPG), polytetrahydrofuran ether diol (PTMG), or polycarbonate diol (PCDL). The preparation method of the hydroxyl-terminated poly(p-dioxane) is as follows: p-Dioxane is purified by multiple rotary evaporation and distillation, and thoroughly dehydrated. After Karl Fischer testing shows a moisture content below 50 ppm and a gas phase purity of 99.9%, it is placed in a polymerization flask, nitrogen is introduced, and a certain proportion of 1,4-butanediol is added. The temperature is raised to 100-120°C, and a toluene solution of stannous octoate is added dropwise. The reaction is carried out for 2 hours. After the reaction is completed, the mixture is cooled to room temperature and pulverized to obtain the hydroxyl-terminated poly(p-dioxane). The molar ratio of p-dioxane to 1,4-butanediol is 8:1-20:1; the amount of stannous octoate is 1-3% of the mass of p-dioxane; and the volume ratio of stannous octoate to toluene is 1:10-15. The hydrophilic chain extender is one of dimethylolpropionic acid (DMPA), dimethylolbutyric acid (DMBA), and methyldiethanolamine (MDEA).

[0015] Preferably, the high flame-retardant waterborne polyurethane has an R value of 1.2-1.6 and an enediyne structural unit content of 1%-10 wt%. The high flame-retardant waterborne polyurethane triggers an aromatic cyclization reaction between the polyurethane melting point and decomposition temperature to form a cross-linked structure and a char layer.

[0016] Preferably, the high flame-retardant waterborne polyurethane has a limiting oxygen index of 30% or higher and passes the UL-94 V-0 rating.

[0017] The present invention also provides an application of a high flame-retardant waterborne polyurethane prepared by the preparation method described above in electronic packaging, new energy vehicle interiors, fire-retardant coatings or special textile coatings.

[0018] The present invention has at least the following beneficial effects: (1) For the first time, the classic organic reaction of enediyne aromatic cyclization was applied to the field of polymer flame retardancy. A new intelligent flame retardant mechanism of "high temperature triggered self-crosslinking to char" was creatively designed, which fundamentally broke away from the "melting droplet promotion" constraint of traditional phosphorus flame retardants. (2) Excellent flame retardant and anti-dripping properties: Under high temperature conditions in a fire, the enediyne structure rapidly undergoes aromatic cyclization, initiating intramolecular / intermolecular crosslinking, resulting in a sharp increase in melt viscosity, effectively suppressing dripping; at the same time, the reaction generates a dense carbon layer rich in polycyclic aromatic hydrocarbons, which plays an excellent role in heat insulation and oxygen barrier, enabling the material to reach UL-94 V-0 level with an LOI greater than 30%; (3) Environmentally friendly: This technology does not rely on halogen or phosphorus-based flame retardants, has low smoke density during combustion, and releases no toxic gases, meeting the requirements of green environmental protection; (4) Durable performance and good overall performance: Since the enediyne structure is covalently bonded to the molecular chain, there is no migration or precipitation problem, resulting in durable flame retardant performance. At the same time, through precise design of the molecular structure, excellent mechanical properties, water resistance and processing stability can be maintained while imparting excellent flame retardancy.

[0019] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0020] Figure 1 The heat release rate curves of cone calorimetry tests for Examples 2-4 and Comparative Example 1 are shown. Figure 2 The total heat release curves are the cone calorimetry test results of Examples 2-4 and Comparative Example 1; Figure 3 The hydrogen nuclear magnetic resonance spectrum of HEEOD in Example 1 is shown. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0022] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not imply the presence or addition of one or more other elements or combinations thereof.

[0023] Example 1: In a side-supported flask, 1.26 g of 1,2-diethynylbenzene, 2.50 g of 2-bromoethanol, 0.14 g of bis(triphenylphosphine)palladium dichloride, 0.038 g of cuprous iodide, and 50 mL of triethylamine were added. The mixture was stirred at 60 °C for 12 hours under nitrogen protection and in the dark. After the reaction, the mixture was filtered, the solvent was removed by rotary evaporation, and the crude product was purified by silica gel column chromatography to obtain a white solid product (HEEOD) containing an enediyne diol chain extender, with a yield of 75%. Its structure was confirmed by 1H NMR spectroscopy. Figure 3 The NMR spectrum of HEEOD is shown in the figure. It is clear from the figure that characteristic peaks of the hydrogen atom on the methylene group in the HEEOD structure appear at δ 2.68 (Hc) and 3.76 (Hd), respectively; characteristic peaks of the hydrogen atom on the benzene ring in the HEEOD structure appear at δ 7.16 (Ha) and 7.3 (Hb), respectively, indicating the synthesis of HEEOD. The hydrogen atom of the hydroxyl group in HEEOD is not shown in the spectrum because, theoretically, it should peak at around 4.2 ppm. However, deuterated chloroform was used as the solvent, which easily contains water, and the water peak overlapped with the OH atom, so the OH atom did not appear.

[0024] Example 2: In a four-necked flask equipped with a stirrer, thermometer, and condenser, 0.02 mol of dihydroxyl-terminated poly(p-dioxanone) (Mn=2500) was added, and the mixture was dehydrated under vacuum at 110°C for 2 hours. The temperature was then lowered to 80°C, nitrogen gas was introduced, and 0.04 mol of isophorone diisocyanate and 4 drops of dibutyltin dilaurate catalyst were added. The reaction was continued for 2 hours to obtain a prepolymer. The system was then cooled to 60°C, and 0.006 mol of HEEOD (synthesized in Example 1) and 0.005 mol of 1,4-butanediol were added sequentially. The reaction was continued for 1.5 hours, followed by the addition of 0.012 mol of dimethylolpropionic acid, and the reaction was continued for another hour. 20 mL of acetone was added to reduce viscosity, and the temperature was lowered to 40°C. 0.012 mol of dimethylolpropionic acid was then added. Triethylamine was added and neutralized for 15 minutes. Under high-speed stirring, a suitable amount of deionized water was slowly added for emulsification. Finally, acetone was removed by vacuum distillation to obtain an aldenyne-containing waterborne polyurethane dispersion with a solid content of approximately 30%. The dispersion was cast onto a polytetrafluoroethylene (PTFE) plate and dried at room temperature to form a film, yielding a highly flame-retardant waterborne polyurethane (FWPU-1). Flame retardant performance testing was conducted. The results showed that the material passed the UL-94 V-0 test with a limiting oxygen index of 28.5%.

[0025] Example 3: In a four-necked flask equipped with a stirrer, thermometer, and condenser, 0.02 mol of dihydroxyl-terminated poly(p-dioxane) (Mn=2500) was added, and the mixture was dehydrated under vacuum at 110°C for 2 hours. The temperature was then lowered to 80°C, nitrogen gas was introduced, and 0.04 mol of isophorone diisocyanate and 4 drops of dibutyltin dilaurate catalyst were added. The reaction was continued for 2 hours to obtain a prepolymer. The system was then cooled to 60°C, and 0.012 mol of HEEOD (synthesized in Example 1) and 0.002 mol of 1,4-butanediol were added sequentially. The reaction was continued for 1.5 hours, followed by the addition of 0.008 mol of dimethylolpropionic acid, and the reaction was continued for another hour. 20 mL of acetone was added to reduce viscosity, and the temperature was lowered to 40°C. 0.012 mol of acetone was then added. Triethylamine was added and neutralized for 15 minutes. Under high-speed stirring, an appropriate amount of deionized water was slowly added for emulsification. Finally, acetone was removed by vacuum distillation to obtain an aldenyne-containing waterborne polyurethane dispersion with a solid content of about 30%. The dispersion was cast onto a polytetrafluoroethylene plate and dried at room temperature to form a film, resulting in a highly flame-retardant waterborne polyurethane (FWPU-2). Flame retardant performance was tested. The flame retardant performance test results showed that the material could pass the UL-94 test V-0 rating with a limiting oxygen index of 31.2%.

[0026] Example 4: In a four-necked flask equipped with a stirrer, thermometer, and condenser, 0.015 mol of dihydroxyl-terminated poly(p-dioxanone) (Mn=2500) and 0.013 mol of polycaprolactone diol (Mn=2000) were added, and the mixture was dehydrated under vacuum at 110°C for 2 hours. The temperature was then lowered to 80°C, nitrogen gas was introduced, and 0.04 mol of isophorone diisocyanate and 4 drops of dibutyltin dilaurate catalyst were added. The reaction was continued for 2 hours to obtain a prepolymer. The system was then cooled to 60°C, and 0.008 mol of HEEOD (synthesized in Example 1) was added sequentially. The reaction was continued for 1.5 hours, followed by the addition of 0.01 mol of dimethylolpropionic acid, and the reaction was continued for another hour. 20 mL of acetone was added to reduce viscosity, and the temperature was lowered to 40°C. 0.012 mol of acetone was then added. Triethylamine was added and neutralized for 15 minutes. Under high-speed stirring, an appropriate amount of deionized water was slowly added for emulsification. Finally, acetone was removed by vacuum distillation to obtain an aldenyne-containing waterborne polyurethane dispersion with a solid content of about 30%. The dispersion was cast onto a polytetrafluoroethylene plate and dried at room temperature to form a film, resulting in a highly flame-retardant waterborne polyurethane (FWPU-3). Flame retardant performance was tested. The flame retardant performance test results showed that the material could pass the UL-94 test V-0 rating with a limiting oxygen index of 29.2%.

[0027] Comparative Example 1: In a four-necked flask equipped with a stirrer, thermometer, and condenser, 0.02 mol of dihydroxyl-terminated poly(p-dioxanone) (Mn=2500) was added, and the mixture was dehydrated under vacuum at 110°C for 1 hour. The temperature was then lowered to 80°C, nitrogen gas was introduced, and 0.04 mol of isophorone diisocyanate and 4 drops of dibutyltin dilaurate catalyst were added. The reaction was continued for 2 hours to obtain a prepolymer. The system was then cooled to 60°C, and 0.01 mol of 1,4-butanediol was added sequentially. The reaction was continued for 1.5 hours, followed by the addition of 0.012 mol of dimethylolpropionic acid, and the reaction was continued for another hour. 20 mL of acetone was added to reduce viscosity, and the temperature was lowered to 40°C. 0.012 mol of dimethylolpropionic acid was then added. Triethylamine was added and neutralized for 15 minutes. Under high-speed stirring, an appropriate amount of deionized water was slowly added for emulsification. Finally, acetone was removed by vacuum distillation to obtain an aldenyne-containing waterborne polyurethane dispersion with a solid content of about 30%. The dispersion was cast onto a polytetrafluoroethylene plate and dried at room temperature to form a film, resulting in a highly flame-retardant waterborne polyurethane (WPU). Flame retardant performance was tested. The flame retardant performance test results showed that the material exhibited stepless vertical burning performance and a limiting oxygen index of 19.5%.

[0028] Figure 1 and Figure 2 The figures show the heat release rate (HRR) and total heat release (THR) curves from the cone calorimetry tests of the comparative and example samples. As can be seen from the figures, the ignition time of the polyurethane increased after introducing the enediyne structure, from 22s for the unmodified waterborne polyurethane to 23-30s. This is mainly due to the improved thermal stability of the material after adding the flame retardant, which raises the ignition point and thus delays the ignition time. Peak heat release rate (PHRR) and total heat release are important parameters for evaluating fire safety. The comparative sample burned particularly rapidly after ignition, with PHRR and THR reaching as high as 633 kW / m³. 2 and 103.6 MJ / m 2 After introducing the enediyne active monomer, the PHRR of the material decreased to 445 and 461 kW / m, respectively. 2 The THR levels decreased to 61.0 and 48.6 MJ / m, respectively. 2 The results show that the introduction of the enediyne structure improves the flame retardant performance of waterborne polyurethane materials in real fires.

[0029] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A waterborne polyurethane with high flame retardant properties, characterized in that, The waterborne polyurethane molecular chain contains an enediyne structure that undergoes an aromatic cyclization reaction at a specific temperature, triggering cross-linking to form carbon. The enediyne structure is introduced into the hard and soft segments of polyurethane by using active monomers as chain extenders or end-capping agents. The active monomer is: ; Alternatively, the active monomer may be any one of the following general structural formulas: Formula I, Formula II, Formula III, or Formula IV. Among them, general formula I is: HO-R1-C≡C-R2-C≡C-R1-OH; General formula II is: H2N-R3-NH-C≡C-R2-C≡C-NH-R3-NH2; General formula III is: HO-R1-C≡C-R2-C≡C; General formula IV is: H2N-R3-C≡C-R2-C≡C; Wherein, R1 is a C2-C6 alkylene or oxyalkylene; R2 is a C2 olefin segment; and R3 is a C2-C6 alkylene.

2. The high flame-retardant waterborne polyurethane according to claim 1, characterized in that, The enediyne structure described herein undergoes cross-linking at 160-200℃ to form an aromatic structure.

3. A method for preparing a waterborne polyurethane with high flame retardant properties as described in any one of claims 1 to 2, characterized in that, Includes the following steps: Step 1: Synthesize active monomers containing enediyne structures: Take the active monomers and prepare diol or diamine monomers via the Sonogashira coupling reaction; Step 2, Preparation of prepolymer: Under inert gas protection, the polymer polyol and diisocyanate are reacted at 60-90℃ for 1-3 hours; Step 3: Chain extension to introduce functional units: Add active monomers containing enediyne structures and other small molecule chain extenders to the prepolymer obtained in Step 2, and continue the reaction for 1-2 hours; Step 4, hydrophilic chain extension and neutralization: Add a chain extender containing a hydrophilic group to the reaction in Step 3 and react, then add a neutralizing agent to neutralize and generate a carboxylate; Step 5, Emulsification: Under high shear stirring, deionized water is added to the reaction system of Step 4 for emulsification to obtain an aqueous polyurethane dispersion; Step 6, Post-treatment: Coat the waterborne polyurethane dispersion into a film; The polymer polyol is one or more of the following: dihydroxyl-terminated poly(p-dioxanone), polycaprolactone diol, polyethylene glycol, polypropylene glycol, polytetrahydrofuran ether diol, and polycarbonate diol.

4. The method for preparing high flame-retardant waterborne polyurethane according to claim 3, characterized in that, The diisocyanate is any one of isophorone diisocyanate, hexamethylene diisocyanate, toluene diisocyanate or diphenylmethane diisocyanate; The hydrophilic chain extender is one of dimethylolpropionic acid and dimethylolbutyric acid; The other small molecule chain extender mentioned is 1,4-butanediol; The neutralizing agent is triethylamine.

5. The method for preparing high flame-retardant waterborne polyurethane according to claim 3, characterized in that, The high flame-retardant waterborne polyurethane has an R value of 1.2-1.6 and an enediyne structural unit content of 1%-10 wt%. The high flame-retardant waterborne polyurethane triggers an aromatic cyclization reaction between the polyurethane melting point and decomposition temperature to form a cross-linked structure and a char layer.

6. The method for preparing high flame-retardant waterborne polyurethane according to claim 3, characterized in that, The aforementioned high flame-retardant waterborne polyurethane has a limiting oxygen index of over 30% and passes the UL-94 V-0 rating.

7. The application of a high flame-retardant waterborne polyurethane prepared by the preparation method according to claim 3 in electronic packaging, new energy vehicle interiors, fire-retardant coatings or special textile coatings.

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