Tough, flame-retardant and hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate as well as preparation method and application of tough, flame-retardant and hydrophobic reactive polyurethane

Abstract

The invention discloses tough, flame-retardant and hydrophobic reactive polyurethane (RPU) based on polyhydroxy ammonium polyphosphate as well as a preparation method and application thereof, and belongs to the crossing field of flame-retardant materials and multifunctional polymers. The specific preparation process is as follows: diglycolamine is grafted to the surface of ammonium polyphosphate through a one-pot ion exchange reaction, and hydroxylated ammonium polyphosphate (aAPP) is prepared. The preparation method comprises the following steps: preparing an aAPP-NCO double-end-capped prepolymer, then carrying out an addition polymerization reaction on the aAPP and the NCO double-end-capped prepolymer under a medium-free condition to prepare flame-retardant RPU (aAPPx-RPU), further introducing polydimethylsiloxane (PDMS) into an RPU main chain, and preparing the tough, flame-retardant and hydrophobic RPU by utilizing the synergistic effect of phosphorus (P), nitrogen (N) and silicon (Si). The preparation method of the tough, flame-retardant and hydrophobic RPU is green and efficient, and can be applied to the fields of fireproof flame-retardant materials, building materials, electronic materials and the like which need to improve safety and durability.

Description

Technical Field

[0001] The invention relates to the cross-technical field of flame retardant materials and multifunctional polymers, in particular to a tough, flame retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate and a preparation method and application thereof. Background Art

[0002] Reactive polyurethane (RPU) films show important research value in the fields of environmental protection, efficient production and high-performance materials. Compared with traditional solvent-based and water-based polyurethanes, RPU has a highly cross-linked structure in a solvent-free medium and exhibits excellent weather resistance, chemical stability and mechanical properties. However, the high flammability and easy melting droplet characteristics of polyurethane limit its application. Although physical blending of flame retardants can enhance flame retardancy, it often reduces mechanical strength and toughness. Therefore, it is particularly important to develop intrinsically flame-retardant RPU that can simultaneously improve flame retardancy and mechanical properties.

[0003] Halogen-free flame retardants, especially nitrogen-phosphorus-silicon compounds, have become the mainstream choice for sustainable development. As an effective flame retardant, the difference in polarity between ammonium polyphosphate (APP) and the PU matrix affects its dispersibility and compatibility. Researchers have improved the compatibility of APP by modification, thereby improving the flame retardancy and mechanical properties of polyurethane composites, but this may reduce toughness. Silicon compounds have attracted attention due to their thermal stability and flexibility, and usually need to be combined with other flame retardants to achieve better flame retardant effects. Summary of the invention

[0004] The present invention aims to address the deficiencies in the prior art and proposes a tough, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate, and a preparation method and application thereof. The method adopts an organic-inorganic hybrid structure, optimizes the hard segment arrangement by introducing inorganic ions with high steric hindrance, and effectively prevents crack propagation by using a flexible silicon-oxygen bond structure. This design significantly improves the strength and toughness of the polyurethane, while giving it multifunctional properties such as flame retardancy and hydrophobicity. In addition, the preparation process is simple to operate, has a high yield, does not involve the volatilization of toxic solvents, and exhibits good environmental friendliness. This multifunctional polyurethane material has broad market prospects in various applications, showing excellent performance and sustainability.

[0005] The present invention proposes an organic-inorganic hybrid structure strategy, synthesizing hydroxylated ammonium polyphosphate (aAPP) through ion exchange reaction and in-situ polymerizing it with polysiloxane polyol to form an aAPP / Si@RPU structure. This design promotes the microphase separation of RPU, improves the strength and toughness of the material, and at the same time, through the interaction between the decomposition products of aAPP and the Si-O layer of polysiloxane polyol, a dual flame retardant effect is achieved, significantly improving the flame retardant and hydrophobic properties of RPU.

[0006] Based on the above purpose, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a tough, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate and a preparation method and application thereof, comprising the following steps:

[0008] S1. Preparation of ethanol-water solution system: Under nitrogen atmosphere, mix a certain proportion of water and ethanol, pour into a three-necked flask and stir for 5-20 min;

[0009] S2. Preparation of amino alcohol solution system: inject a certain amount of amino alcohol into the three-necked flask of ethanol aqueous solution in step S1, and stir for a certain period of time to ensure sufficient mixing;

[0010] S3, preparation of amino alcohol surface modified ammonium polyphosphate solution: adding a certain amount of APP powder particles to the solution of step S2, then condensing and refluxing under nitrogen atmosphere, mixing and stirring to react for 2-6 hours, and heating to 50-90° C. to promote the reaction;

[0011] S4. Preparation of hydroxylated ammonium polyphosphate from amino alcohol surface-modified ammonium polyphosphate solution Reaction monitoring: Use pH test paper to detect whether the reaction is complete. If the pH value measured every 2-10 minutes is between 7 and 10, the reaction is considered to be complete;

[0012] S5, preparation of hydroxylated ammonium polyphosphate (aAPP): After the amino alcohol surface-modified ammonium polyphosphate solution prepared in step S4 is cooled to room temperature, the unreacted APP is precipitated and the chain segments produced during the reaction are crystallized, and the precipitate is filtered by vacuum suction, and washed with anhydrous ethanol 2-5 times to remove impurities. Subsequently, the obtained white solid is dried in a vacuum oven at 40-80°C for 8-24h to constant weight, and after cooling to room temperature, hydroxylated modified ammonium polyphosphate aAPP is obtained;

[0013] S6. Preparation of component A and component B of a tough, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate: polyol (polyester / polyether polyol, polysiloxane polyol), amino alcohol-coated ammonium polyphosphate (aAPP), small molecule chain extender, amine catalyst, metal catalyst, and leveling agent C-15 are uniformly mixed by high-speed stirring to obtain component A; isocyanate and polyol are heated to 50-80°C under a nitrogen atmosphere, and mechanically stirred for 1-3 hours to prepare a polyurethane prepolymer with an isocyanate content of 10%-28%, to obtain component B;

[0014] S7. A strong, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate and a preparation method thereof: Mix the component B and the component A described in step S6 in a certain proportion, stir at high speed in a low-pressure casting machine to mix the mixed liquid evenly, and then quickly spray it on the release paper. After vacuum drying at 80-120°C for 5-12h, a strong, flame-retardant, hydrophobic high-performance reactive polyurethane film can be obtained.

[0015] Preferably, in step S1, the mixing ratio of water to ethanol should be maintained between 20:9 and 40:1. When it is lower than 20:9, the solubility of APP is insufficient, which may affect the reaction efficiency and uniformity; when it is higher than 40:1, the concentration of reactants is too low, which will reduce the reaction rate and product yield.

[0016] Preferably, in step S2, the amino alcohol is one or more of ethanolamine (EA), diethanolamine (DEA), diglycolamine (DGA), dopamine (DA), and propanolamine (PA), but is not limited thereto; the stirring time is 5-10 min;

[0017] Preferably, in the steps S2 and S3, the ratio of amino alcohol to ammonium polyphosphate is 1:2-1:7; too low a ratio will result in incomplete reaction, insufficient degree of hydroxylation, and limited performance improvement; too high a ratio will result in excessive cross-linking of the amino alcohol, reducing the hydroxylation modification effect of APP, and subsequently introducing it into the polyurethane system to increase the brittleness of the material.

[0018] Preferably, in step S5, the drying process is completed at a weight difference of 0.05-0.1 wt% every 2-3 hours.

[0019] Preferably, in step S6, in component A, the polyester / polyether polyol is polyester polyol or / and polyether polyol, the polyester polyol is polycarbonate diol, the polyether polyol is polytetramethylene glycol, the polysiloxane polyol is polydimethylsiloxane hydroxyl-terminated polyol (Mn=900-3000 g / mol);

[0020] In component B, the polyol (Mn=900-3000 g / mol) is one or more of polytetramethylene ether glycol (PTMEG), castor oil (CO), polycarbonate diol (PCDL), polyethylene glycol (PEG), polyoxypropylene glycol (PPG), hydroxy silicone oil (HSO), and polydimethylsiloxane hydroxyl-terminated (PDMS), but is not limited thereto;

[0021] Preferably, the small molecule chain extender is one or more of hexamethylenediamine (HMDA), ethylene glycol (EG), 1,4-butanediol (1,4-BDO), ethanolamine (ETA), diethylenetriamine (DETA), 1,3-butanediol (1,3-BDO), and vinylaminosilane (VAS), but is not limited thereto;

[0022] Preferably, the amine catalyst is dimethylethanolamine, N-methylmorpholine, N,N-dimethylcyclohexylamine, triethylenediamine; the metal catalyst is one or more of dibutyltin dilaurate, stannous octoate, and stannous oleate, but is not limited thereto;

[0023] Preferably, the mass ratio of the polyester / polyether polyol, polysiloxane polyol, amino alcohol-coated ammonium polyphosphate (aAPP), small molecule chain extender, and leveling agent C-15 in component A described in step S6 is 100:0-55:0-50:2-25:2-11, and the mass ratio of the polyester / polyether polyol, polysiloxane polyol, amino alcohol-coated ammonium polyphosphate, chain extender, amine catalyst, and metal catalyst in component A is 21-31:12-50:26-38:0.025-0.25:0.025-0.25; further preferably, it is 21-31:12-26:26-38:0.025-0.25:0.025-0.25. The amount of amine catalysts and metal catalysts used accounts for 0.05-0.5% of the total reaction system weight. The catalyst content is lower than 0.05wt%: the reaction rate is reduced, which may lead to incomplete reaction and affect product performance. The catalyst content is higher than 0.5wt%: the reaction is too fast, which increases the risk of side reactions and leads to uneven products; in component B, the polyol is one or more of polytetramethylene ether diol, castor oil, polycarbonate diol, polyethylene glycol, polyoxypropylene diol, hydroxy silicone oil, and polydimethylsiloxane hydroxyl end-capping; the mass ratio of isocyanate to polyol in component B is 10:1-10:5. The mass ratio of isocyanate to polyol is lower than 10:1, which will reduce the reaction rate and affect the formation of polymerization chains, thereby reducing the mechanical strength, durability and cross-linking degree of the material; the mass ratio of isocyanate to polyol is higher than 10:5, which will increase the risk of toxicity, lead to uneven polyurethane reaction, affect product performance, and may induce side reactions;

[0024] Preferably, in step S6, the isocyanate index R (-NCO / -OH) of component B and component A is 0.9 to 1.3. If R is less than 0.9, the reaction rate will be significantly reduced, thereby affecting the formation of the polymer chain and the degree of crosslinking, and ultimately causing the mechanical strength and durability of the material to decrease. On the contrary, if R is greater than 1.3, the isocyanate index is too high, which may increase the toxicity risk and cause the reaction to be non-uniform, thereby affecting the physical properties and chemical stability of the final product.

[0025] The second aspect of the present invention provides a tough, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate and a preparation method and application thereof, which is prepared according to the above preparation method.

[0026] The third aspect of the present invention provides a tough, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate, a preparation method thereof, and an application thereof in public safety materials such as adhesives, elastomers, and synthetic leather.

[0027] Compared with the prior art, the present invention has one of the following advantages:

[0028] 1) Improve the overall performance of the material: The present invention uses an organic-inorganic hybrid strategy to induce microphase separation of the composite material, combining the high-strength support of the inorganic phase with the flexibility of the organic matrix, optimizing the mechanical properties and improving the tensile strength and ductility. Microphase separation improves the stress transfer efficiency, reduces the risk of brittle fracture, and enhances impact resistance and energy absorption. In addition, inorganic components such as phosphorus-based flame retardants can form a protective carbonized layer, reduce the release of combustible gases, improve thermal stability and flame retardant efficiency, and thus enhance application safety.

[0029] 2) Green process: The present invention adopts a simple and efficient solvent-free polymerization method to connect inorganic and organic monomers to the polymer backbone. This method has the advantages of simple operation and environmental friendliness, and can effectively avoid the influence of solvents on polymer properties. Through flexible design and replacement of monomers, we can accurately control the structure and properties of polymers according to specific needs. In addition, this technology also supports the design of ultra-large polymer molecular weight, providing greater flexibility and possibilities for the development of new materials, and further expanding its potential in various applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 SEM images of (a) ammonium polyphosphate (APP) and (b) hydroxylated modified ammonium polyphosphate (aAPP), and (c) EDS image of hydroxylated modified ammonium polyphosphate (aAPP);

[0031] Figure 2 FTIR graphs of in-situ polymerized reactive polyurethanes of Example 1, Comparative Example 1, Example 4, Example 5 and Comparative Example 4;

[0032] Figure 3 Graphs of heat release rates for Example 1, Example 4 and Example 5;

[0033] Figure 4 It is the total release heat diagram of Example 1, Example 4 and Example 5;

[0034] Figure 5 The mass loss rate diagrams of Example 1, Example 4 and Example 5;

[0035] Figure 6 It is a total smoke production diagram of Example 1, Example 4 and Example 5;

[0036] Figure 7 Graphs showing heat release rates for Example 1, Example 4, and Example 5.

[0037] Figure 8 The present invention is a schematic flow diagram of a method for preparing a tough, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] In the present invention, unless otherwise specified, all raw materials can be purchased from the market or are commonly used in the industry. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art.

[0040] The preferred embodiment of the present invention is as follows Figure 8 As shown, a method for preparing a tough, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate is provided, comprising the following steps:

[0041] (1) Preparation of ethanol-water solution system: Under nitrogen atmosphere, mix 600 ml of water and 20 ml of ethanol, pour into a three-necked flask and stir for 10 min;

[0042] (2) Preparation of amino alcohol solution system: 54 g of diglycolamine was injected into the three-necked flask of ethanol aqueous solution in step S1, and stirred for 8 min to ensure sufficient mixing;

[0043] (3) Preparation of amino alcohol surface modified ammonium polyphosphate solution: 100 g of APP powder particles were added to the solution in step S2, followed by condensation and reflux under nitrogen atmosphere, mixing and stirring for 5 h, and then heating to 65 ° C to promote the reaction for 8 h;

[0044] (4) Preparation of hydroxylated ammonium polyphosphate from amino alcohol surface-modified ammonium polyphosphate solution Reaction monitoring: Use pH test paper to detect whether the reaction is complete. If the pH value measured every 7 minutes is between 8 and 9, the reaction is considered to be complete;

[0045] (5) Preparation of hydroxylated ammonium polyphosphate (aAPP): After the amino alcohol surface-modified ammonium polyphosphate solution prepared in step S4 is cooled to room temperature, the unreacted APP precipitates and the chain segments produced during the reaction crystallize and precipitate, and the precipitate is filtered by vacuum suction and washed with anhydrous ethanol for 2-5 times to remove impurities. Subsequently, the obtained white solid is dried in a vacuum oven at 45° C. for 12 hours to constant weight, and then cooled to room temperature to obtain hydroxylated modified ammonium polyphosphate aAPP;

[0046] (6) Preparation of a tough, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate: polyester polyol (polycarbonate diol, M n =2000g / mol), polysiloxane polyol (polydimethylsiloxane hydroxyl terminated, M n =2000g / mol), amino alcohol-coated ammonium polyphosphate (aAPP), small molecule chain extender (diglycolamine), amine catalyst (triethylenediamine), metal catalyst (stannous octoate), and leveling agent C-15 were uniformly mixed by high-speed stirring to obtain component A; isocyanate (isophorone diisocyanate / HDI trimer, mass ratio 1 / 1) and polyether polyol (polytetramethylene ether glycol, M n =2000 g / mol,) under nitrogen atmosphere, the mass ratio of isocyanate to polytetramethylene ether diol is 2.8:1, the temperature is raised to 60°C, and mechanically stirred for 3 hours to prepare a polyurethane prepolymer with an isocyanate content of 25%, that is, component B;

[0047] (7) A strong, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate and a preparation method thereof: Component B and component A described in step S6 are mixed in a certain proportion by high-speed stirring in a low-pressure casting machine until the mixed liquid is uniformly mixed, and then quickly sprayed on release paper. After vacuum drying at 90°C for 8 hours, a strong, flame-retardant, hydrophobic, high-performance reactive polyurethane film can be obtained.

[0048] Table 1 shows a tough, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate and a preparation method and application thereof of Examples 1 to 9 and a specific preparation method of Comparative Examples 1 to 5.

[0049] Table 1

[0050]

[0051] The mechanical properties, softness and limiting oxygen index of the ordered microstructure mechanically reinforced in-situ reactive polyurethane material prepared in the above example were tested. The results are shown in Table 2.

[0052] Table 2

[0053]

[0054] Note: The softness and hardness of the hand feel are tested according to the ASTM D2240-18 standard. The higher the value, the softer the hand feel. The tensile strength and elongation at break are tested according to the ASTM D638-14 standard. The limiting oxygen index is tested according to the ISO 4589-2 standard. A high oxygen index indicates that the material is not easy to burn, and a low oxygen index indicates that the material is flammable. It is generally believed that materials with an oxygen index of less than 22% are flammable materials, materials with an oxygen index between 22% and 27% are flammable materials, and materials with an oxygen index of more than 27% are flame-retardant materials. The water contact angle is tested according to the GB / T30693-2014 standard. When the contact angle θ>90°, the surface of the material is not easily wetted and is hydrophobic. When θ>150°, it is super hydrophobic. The degree of crosslinking of polyurethane is determined by the swelling equilibrium method to determine the degree of crosslinking of the crosslinked polymer.

[0055] Figure 1-2 The data in Table 1-1 show that, compared with ammonium polyphosphate, hydroxylated ammonium polyphosphate not only successfully achieves coating, but also confirms that it can be in-situ grafted to the main chain of reactive polyurethane. In addition, under the synergistic effect of hydroxylated ammonium polyphosphate prepared by the method of the present invention and polysiloxane polyol, the reactive polyurethane resin film exhibits excellent surface softness, hydrophobicity, mechanical strength and flame retardant properties, which is verified in Example 5. These properties show significant improvement when compared with Example 1 in which hydroxylated ammonium polyphosphate is not modified. At the same time, the comparative test shows that whether it is ammonium polyphosphate that is not modified by hydroxylation (Comparative Example 1) or the case of using polysiloxane polyol alone (Comparative Examples 2 to 5), its flame retardant effect is not as obvious as that of Example 5. In addition, their improvement in mechanical properties is not as significant as that of Example 5. This shows that this technology not only enhances the flame retardant properties of solvent-free polyurethane, but also greatly improves its mechanical properties and improves surface softness, which is of great significance for the implementation of solvent-free polyurethane resins in the fields of automotive interior materials.

[0056] Figure 2-7The data show that compared with Example 1 without the introduction of hydroxylated ammonium polyphosphate, Examples 4 and 5 respectively introduce hydroxylated ammonium polyphosphate (aAPP) and a composite of hydroxylated ammonium polyphosphate (aAPP) and polysiloxane (PDMS), which significantly improves the flame retardant properties. This process inhibits the spread of flames through the H2O and NH3 released by the decomposition of aAPP at high temperature. The dense carbon layer formed effectively isolates heat and combustible gases, reduces the heat release rate (HRR), total smoke production (TSP) and total heat release (THR). In addition, the synergistic effect of P and Si in Example 5 enhances the structural stability and thermal insulation effect of the carbon layer, further improves the flame retardant effect of RPU, and shows good implementation prospects. In addition, aAPP and PDMS significantly improve the strength and toughness of polyurethane through the synergistic effect of molecular structure. The hydroxyl and phosphate groups in aAPP form hydrogen bonds with the polyurethane chain segments, enhancing the intermolecular interaction force; while the silicon oxygen chain structure of PDMS provides excellent flexibility, can effectively absorb impact energy, and reduce the brittleness of the material. Excessive introduction of PDMS monomers makes PU film formation difficult and more thermodynamically incompatible.

[0057] It should be emphasized that although the above description only shows the preferred embodiments of the present invention, it is not intended to limit the scope of the present invention. Even though the present invention has been described in detail through specific embodiments, it is still possible for those skilled in the art to modify or replace the technical solutions described within the spirit and principle of the present invention. Therefore, the actual protection scope of the present invention should be defined according to the attached claims.

Claims

1. A method for preparing a tough, flame-retardant, hydrophobic reactive polyurethane based on polyhydroxy ammonium polyphosphate, characterized in that: The following steps are involved: S1, mixing water and ethanol to obtain an ethanol aqueous solution; S2, injecting amino alcohol into the ethanol aqueous solution in step S1, mixing thoroughly, to obtain a mixed solution; S3, preparation of amino alcohol surface modified ammonium polyphosphate solution: adding ammonium polyphosphate powder particles to the mixed solution of step S2, then condensing and refluxing under a nitrogen atmosphere, mixing and stirring to react, and heating to 50-90° C. to promote the reaction; S4. When the pH value measured in each time period is between 7 and 10, the reaction is considered to be completed, and a reaction solution is obtained; S5, cooling the reaction solution obtained in step S4, precipitating unreacted ammonium polyphosphate and crystallizing the chain segments produced during the reaction, filtering the precipitate by vacuum suction, washing with anhydrous ethanol to remove impurities, and then drying the obtained white solid, cooling it, to obtain hydroxylated ammonium polyphosphate; S6. Evenly mix the polyester / polyether polyol, polysiloxane polyol, hydroxylated ammonium polyphosphate, chain extender, amine catalyst, metal catalyst, and leveling agent to obtain component A; heat the isocyanate and polyol to 50-80° C. under a nitrogen atmosphere, and mechanically stir for 1-3 hours to prepare a polyurethane prepolymer to obtain component B; S7, mixing component B and component A in step S6 evenly, and then curing them to obtain a strong, flame-retardant, hydrophobic reactive polyurethane.

2. The preparation method according to claim 1, characterized in that: In step S1, the volume ratio of water to ethanol is 20:9-40:

1.

3. The preparation method according to claim 1, characterized in that: In step S2, the amino alcohol is one or more of ethanolamine, diethanolamine, diglycolamine, dopamine, and propanolamine.

4. The preparation method according to claim 1, characterized in that: The mass ratio of the amino alcohol in step S2 to the ammonium polyphosphate in step S3 is 1:1-1:

10.

5. The preparation method according to claim 1, characterized in that: In step S6, in component A, the polyester / polyether polyol is polyester polyol or / and polyether polyol, the polyester polyol is polycarbonate diol, the polyether polyol is polytetramethylene glycol, and the polysiloxane polyol is polydimethylsiloxane hydroxyl-terminated; The chain extender is one or more of hexamethylenediamine, ethylene glycol, 1,4-butanediol, ethanolamine, diethylenetriamine, 1,3-butanediol, and vinylaminosilane; The amine catalyst is one or more of dimethylethanolamine, N-methylmorpholine, N,N-dimethylcyclohexylamine, and triethylenediamine; The metal catalyst is one or more of dibutyltin dilaurate, stannous octoate and stannous oleate.

6. The preparation method according to claim 5, characterized in that: In step S6, the mass ratio of the polyester / polyether polyol, polysiloxane polyol, amino alcohol-coated ammonium polyphosphate, chain extender, amine catalyst, and metal catalyst is 21-31: 12-50: 26-38: 0.025-0.25: 0.025-0.25; more preferably 21-31: 12-26: 26-38: 0.025-0.25: 0.025-0.

25.

7. The preparation method according to claim 1, characterized in that: In step S6, in component B, the polyol is one or more of polytetramethylene glycol, castor oil, polycarbonate diol, polyethylene glycol, polyoxypropylene diol, hydroxy silicone oil, and polydimethylsiloxane hydroxyl-terminated; The mass ratio of the isocyanate to the polyol is 10:1-10:

5.

8. The preparation method according to claim 1, characterized in that: In step S7, the mass ratio of component B to component A is 100:86-127; The construction and curing conditions are: vacuum drying at 80-120℃ for 5-12h.

9. A tough, flame-retardant, hydrophobic reactive polyurethane prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the tough, flame-retardant, hydrophobic reactive polyurethane according to claim 9 as a public safety material.

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