High-flame-retardant polyurethane material as well as preparation method and application thereof

Abstract

The invention relates to a high-flame-retardant polyurethane material as well as a preparation method and application thereof. The high-flame-retardant polyurethane material is prepared from the following raw materials: polyol, isocyanate and a flame retardant, the flame retardant comprises a modified hydroxide, an inorganic phosphorus flame retardant and a phosphate flame retardant. By reasonably compounding a flame retardant system and designing the component formula of the preparation raw materials of the polyurethane material, the prepared polyurethane material has excellent mechanical properties, heat resistance and flame retardance.

Description

Technical Field

[0001] This invention relates to the field of polyurethane materials technology, and in particular to a high flame-retardant polyurethane material, its preparation method, and its application. Background Technology

[0002] Thermoplastic polyurethane elastomer (TPU) is an excellent polymer that combines the high elasticity of rubber with the plasticity of plastics, possessing mechanical properties, abrasion resistance, and excellent resistance to chemical solvents and greases. However, the limiting oxygen index of thermoplastic polyurethane materials ranges from approximately 16-18%, making them highly flammable and exhibiting dripping during combustion, severely limiting their application in high-safety environments. In existing technologies, a common method to improve the flame-retardant properties of polyurethane elastomers is to add flame retardants.

[0003] However, the use of a single flame retardant is often insufficient to meet the requirements for high flame retardancy, and usually requires a high addition amount to achieve the ideal flame retardant effect, which can seriously affect the mechanical and processing properties of polyurethane materials. Conventional flame retardant synergistic compounding schemes include technologies such as "phosphorus-nitrogen synergy (CN105175777A)" and "bromine-antimony synergy (CN101875782A)," but most of the flame retardants used in these schemes have poor compatibility with polyurethane materials, resulting in a serious decline in the mechanical properties of polyurethane materials. Furthermore, the large amounts of bromine compounds, organophosphorus compounds, and heavy metals added will release a variety of harmful substances during combustion. These substances are persistent, bioaccumulative, and toxic, which will have a significant impact on environmental and safety issues.

[0004] Halogen-free flame retardants are considered an ideal alternative to bromine compounds and organophosphorus compounds in existing flame retardant systems because they do not release harmful gases such as hydrogen halides during use, making them more environmentally friendly and beneficial to human health. However, polyurethane materials using halogen-free flame retardants in existing technologies (CN103588946A) exhibit inferior performance compared to traditional flame retardant systems. Furthermore, the poor structural compatibility between halogen-free flame retardants and polyurethane materials leads to low flame retardant efficiency, requiring large-scale addition. Excessive addition of flame retardants disrupts the hydrogen bonds between polyurethane molecular chains, significantly reducing the mechanical properties of the polyurethane material and increasing production costs.

[0005] Therefore, how to provide a novel flame retardant system for use in polyurethane materials that avoids the extensive use of halogenated flame retardants, has excellent structural compatibility with polyurethane, and produces polyurethane materials with both excellent mechanical properties and flame retardancy, while minimizing environmental and safety impacts, has become an urgent problem to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a highly flame-retardant polyurethane material, its preparation method, and its application. By rationally compounding a flame retardant system and designing the component formulation of the raw materials for preparing the polyurethane material, the resulting polyurethane material possesses excellent mechanical properties, heat resistance, and flame retardancy.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a highly flame-retardant polyurethane material, wherein the raw materials for preparing the highly flame-retardant polyurethane material include polyols, isocyanates and flame retardants.

[0009] The flame retardants include modified hydroxides, inorganic phosphorus flame retardants, and phosphate ester flame retardants.

[0010] This invention utilizes a rationally formulated flame retardant system. Phosphate ester flame retardants exhibit excellent compatibility with the polyurethane structure. When combined with halogen- and heavy metal-free hydroxides and inorganic phosphorus flame retardants, the amount of flame retardant used is significantly reduced compared to using a single flame retardant, while simultaneously improving the material's flame retardant performance. Furthermore, to further enhance the compatibility between the hydroxide and the polyurethane structure, this invention modifies the hydroxide. The modified hydroxide exhibits excellent compatibility with polyurethane, further improving the mechanical properties, heat resistance, and flame retardant properties of the polyurethane material.

[0011] Preferably, the mass ratio of the isocyanate, polyol and flame retardant is 1:(0.8-1.3):(0.3-0.7).

[0012] Among them, 0.8-1.3 can be, for example, 0.8, 0.9, 1, 1.1, 1.2 or 1.3; 0.3-0.7 can be, for example, 0.3, 0.4, 0.5, 0.6 or 0.7.

[0013] Preferably, the mass ratio of the modified hydroxide, inorganic phosphorus flame retardant and phosphate ester flame retardant is 1:(0.75-2.5):(0.75-2.5).

[0014] Among them, 0.75-2.5 can be, for example, 0.75, 1, 1.5, 2 or 2.5, etc.

[0015] Preferably, the polyol comprises a polyether polyol.

[0016] Preferably, the number average molecular weight of the polyether polyol is 500-20000, for example, it can be 500, 1000, 2000, 4000, 6000, 8000, 10000, 15000 or 20000.

[0017] Preferably, the polyether polyol includes any one or a combination of at least two of polyethylene glycol, polypropylene glycol, or polytetrahydrofuran polyol, and more preferably a combination of polyethylene glycol and polypropylene glycol.

[0018] Preferably, the mass ratio of polyethylene glycol to polypropylene glycol is (1.2-1.6):1, for example, it can be 1.2:1, 1.3:1, 1.4:1, 1.5:1 or 1.6:1, etc.

[0019] In this invention, the preferred polyol is a combination of polyethylene glycol (PEG) and polypropylene glycol (PPG). PEG provides strength and modulus to the resulting polyurethane material, while PPG provides elasticity and toughness. By adjusting the ratio of the two, the mechanical strength and toughness of the polyurethane material can be balanced. Excessive PPG leads to insufficient strength and hardness, lack of support, and deteriorated mechanical properties; furthermore, the soft segments of the polyurethane material lack a fixed crystalline network, making the material prone to deformation. Insufficient PPG results in poor low-temperature flexibility, decreased hydrolysis resistance, and reduced elasticity. Furthermore, the addition of PEG and PPG also provides the polyurethane material with certain water absorption, antistatic properties, and hydrolysis resistance; within the aforementioned ratio range, the water absorption, antistatic, and hydrolysis resistance properties are also relatively excellent.

[0020] Preferably, the isocyanate includes any one or a combination of at least two of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI) or isoflurone diisocyanate (IPDI), and is more preferably diphenylmethane diisocyanate.

[0021] The preferred isocyanate in this invention is diphenylmethane diisocyanate (MDI). The symmetrical molecular structure of MDI allows the hard segments formed from it to arrange and stack more regularly in the polyurethane material, resulting in a dense and ordered microphase separation structure. Furthermore, its moderate reactivity ensures a moderate reaction rate during polyurethane formation, facilitating production and processing, and exhibits low toxicity during production.

[0022] Preferably, the modified hydroxide is prepared by the following preparation method, the preparation method comprising:

[0023] The modified hydroxide is obtained by mixing the hydroxide, modifier, silane coupling agent and solvent and reacting them.

[0024] Preferably, the mass ratio of the hydroxide, modifier and solvent is 1:(0.01-0.05):(0.5-15).

[0025] Among them, 0.01-0.05 can be, for example, 0.01, 0.02, 0.03, 0.04 or 0.05; 0.5-1.5 can be, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.3, 1.4 or 1.5.

[0026] Preferably, the hydroxide includes aluminum hydroxide and / or magnesium hydroxide.

[0027] Preferably, the modifier includes a silane coupling agent.

[0028] Preferably, the solvent includes ethanol.

[0029] Preferably, the reaction is carried out under alkaline conditions.

[0030] Preferably, the pH value of the alkaline condition is 5.5-7, for example, it can be pH=5.5, pH=5.6, pH=5.8, pH=6, pH=6.2, pH=6.4, pH=6.5, pH=6.6, pH=6.8 or pH=7, etc.

[0031] Preferably, an alkaline substance is used to adjust the pH value of the reaction.

[0032] Preferably, the alkaline substance includes ammonia.

[0033] Preferably, the reaction is carried out under stirring.

[0034] Preferably, the stirring speed is 400-700 rpm, for example, 400 rpm, 500 rpm, 600 rpm or 700 rpm.

[0035] Preferably, the reaction temperature is 50-60℃, for example, 50℃, 52℃, 54℃, 55℃, 56℃, 58℃ or 60℃, and the reaction time is 1-4 h, for example, 1 h, 2 h, 3 h or 4 h.

[0036] Preferably, the modified hydroxide includes coupling agent modified aluminum hydroxide and / or coupling agent modified magnesium hydroxide.

[0037] Preferably, the inorganic phosphorus flame retardant includes any one or a combination of at least two of ammonium polyphosphate, ammonium phosphate salt, calcium phosphate, or magnesium phosphate, and more preferably ammonium polyphosphate.

[0038] Preferably, the phosphorus content of the phosphate ester flame retardant is 12-14%, for example, it can be 12%, 12.5%, 13%, 1.35% or 14%, etc.

[0039] Preferably, the phosphate ester flame retardant includes diphosphite flame retardants and / or phenyl phosphate flame retardants, and more preferably diphosphite flame retardants.

[0040] Preferably, the diphosphite flame retardant includes any one or a combination of at least two of tris(2-chloropropyl) phosphate, dipentaerythritol diphosphite, tris(2-chloroethyl) phosphate, or tris(2,3-dichloropropyl) phosphate, and more preferably tris(2-chloropropyl) phosphate.

[0041] Preferably, the flame retardant comprises a combination of coupling agent-modified aluminum hydroxide, ammonium polyphosphate, and tris(2-chloropropyl) phosphate.

[0042] This invention preferably employs a combined flame retardant system of coupling agent-modified aluminum hydroxide, ammonium polyphosphate, and tris(2-chloropropyl) phosphate. This compounding method overcomes the various shortcomings of single flame retardants. The modified aluminum hydroxide, upon thermal decomposition, releases water vapor and absorbs a large amount of heat, delaying the decomposition of internal materials. Furthermore, the alumina produced during decomposition can coat the material surface, isolating oxygen from combustibles and reducing smoke generation. The tris(2-chloropropyl) phosphate, although containing chlorine, exhibits significant flame retardant effects, high thermal stability, and is less prone to producing harmful gases during combustion. Compared to other environmentally friendly flame retardants, it possesses stronger flame retardant performance, and compared to other phosphate ester flame retardants, it is more environmentally friendly. Moreover, phosphate ester flame retardants have excellent compatibility with the polyurethane structure. The synergistic use of these three components reduces the amount of flame retardant required and improves the flame retardant performance of the material.

[0043] Preferably, the raw materials for preparing the high flame-retardant polyurethane material also include additives.

[0044] Preferably, the mass ratio of the isocyanate to the additive is 1:(0.03-0.06), for example, it can be 1:0.03, 1:0.04, 1:0.05 or 1:0.06, etc.

[0045] Preferably, the additives include mold release agents and / or chain extenders.

[0046] Preferably, the additives include a release agent and a chain extender in a mass ratio of (6-8):1, for example, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, etc.

[0047] Preferably, the release agent comprises fatty alcohol polyoxyethylene ether and / or ethyl lactate.

[0048] Preferably, the weight-average molecular weight of the fatty alcohol polyoxyethylene ether is 300-600, for example, it can be 300, 400, 500 or 600.

[0049] Preferably, the chain extender comprises any one or a combination of at least two of dimethylthiotoluenediamine, diethanolamine, diethyltoluenediamine, or ethylene glycol.

[0050] Secondly, the present invention provides a method for preparing a highly flame-retardant polyurethane material as described in the first aspect, the method comprising the following steps:

[0051] (1) Mix the polyol with optional additives to obtain premix A;

[0052] Isocyanate was mixed with flame retardant to obtain premix B;

[0053] (2) Mix premix A and premix B and react to obtain the high flame retardant polyurethane material.

[0054] Preferably, the reaction temperature in step (2) is 160-180℃, for example, 160℃, 165℃, 170℃, 175℃ or 180℃, and the reaction time is 0.5-2 h, for example, 0.5 h, 1 h, 1.5 h or 2 h.

[0055] Preferably, the reaction in step (2) further includes vacuum degassing.

[0056] Preferably, the temperature of the vacuum degassing is 50-70°C, for example, it can be 50°C, 55°C, 60°C, 65°C or 70°C.

[0057] Preferably, the vacuum degassing temperature is 20-40 min, for example, 20 min, 25 min, 30 min, 35 min or 40 min.

[0058] Preferably, the vacuum degree of the vacuum degassing is -82 to -89 kPa, for example, it can be -82 kPa, -83 kPa, -84 kPa, -85 kPa, -86 kPa, -87 kPa, -88 kPa or -89 kPa, etc.

[0059] Thirdly, the present invention provides an application of the high flame-retardant polyurethane material as described in the first aspect in building materials.

[0060] Compared with the prior art, the present invention has at least the following beneficial effects:

[0061] (1) By rationally compounding the flame retardant system and designing the formulation of the raw material components for preparing polyurethane materials, the present invention can achieve excellent flame retardant performance while reducing the total amount of flame retardant used. Furthermore, reducing the amount of flame retardant added to the resin matrix can avoid the problem of decreased mechanical properties of the resin matrix due to the large amount of flame retardant added, so that the polyurethane material obtained has excellent mechanical properties, heat resistance and flame retardancy.

[0062] (2) The high flame retardant polyurethane material provided by the present invention has an oxygen index of up to 24.7-28.6% and a V-0 rating of UL-94 standard, which has excellent flame retardancy. It also has a tensile strength of up to 25.8-34.0 MPa and an elongation at break of up to 317-360%, which also has excellent mechanical properties. Detailed Implementation

[0063] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0064] The specific information of the materials used in the following specific embodiments of the present invention is as follows:

[0065] Polyethylene glycol, with a number average molecular weight of 6,000-10,000, was purchased from Shandong Yantai Wanhua Chemical Group Co., Ltd.

[0066] Polypropylene glycol, with a number average molecular weight of 4,000-20,000, was purchased from Shandong Yantai Wanhua Chemical Group Co., Ltd.

[0067] Polytetrahydrofuran polyols with a number average molecular weight of 650-4000 were purchased from West Asia Chemical Reagent Co., Ltd.

[0068] Diphenylmethane diisocyanate (MDI), purchased from Shandong Yantai Wanhua Chemical Group Co., Ltd.;

[0069] Ammonium polyphosphate, with a number average molecular weight of 30-100, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0070] Ammonium phosphate, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0071] Tris(2-chloropropyl) phosphate was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0072] Tris(2-chloroethyl) phosphate was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0073] Coupling agent modified aluminum hydroxide is prepared by the following method:

[0074] Aluminum hydroxide (purchased from Zibo Yide New Material Technology Co., Ltd.), modifier (KH550) and ethanol solution (90wt%) were mixed. The mass ratio of aluminum hydroxide, modifier and ethanol solution was 1:0.03:1. Ammonia water was added to adjust the pH of the system to 6. The mixture was reacted at 55℃ and 500 rpm for 3 h. After filtration and drying, the modified aluminum hydroxide was obtained.

[0075] Coupling agent modified magnesium hydroxide is prepared by the following method;

[0076] Magnesium hydroxide (purchased from Zibo Yide New Material Technology Co., Ltd.), modifier (KH550) and ethanol solution (90wt%) were mixed. The mass ratio of magnesium hydroxide, modifier and ethanol solution was 1:0.03:1. Ammonia water was added to adjust the pH of the system to 6. The mixture was reacted at 55℃ and 500 rpm for 3 h. After filtration and drying, the modified aluminum hydroxide was obtained.

[0077] Fatty alcohol polyoxyethylene ether, with a weight-average molecular weight of 300-600, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0078] Example 1

[0079] This embodiment provides a high flame retardant polyurethane material and its preparation method. The raw material components of the high flame retardant polyurethane material are shown in Table 1 (the amount of each component in Table 1 is by weight), where "--" indicates that the component was not added.

[0080] The preparation method includes:

[0081] (1) The polyol composition is mixed with fatty alcohol polyoxyethylene ether and ethylene glycol to obtain premix A;

[0082] Isocyanate was mixed with coupling agent-modified aluminum hydroxide, ammonium polyphosphate and tris(2-chloropropyl) phosphate to obtain premix B;

[0083] (2) Mix premix A and premix B, defoam under vacuum at 60 °C for 0.5 h, and then react and cure at 170 °C for 2 h to obtain the high flame retardant polyurethane material.

[0084] Table 1

[0085]

[0086] Example 6

[0087] This embodiment provides a high flame-retardant polyurethane material and its preparation method. The difference from Embodiment 1 is that polypropylene glycol is replaced with polytetrahydrofuran polyol.

[0088] Example 7

[0089] This embodiment provides a high flame-retardant polyurethane material and its preparation method. The difference from Embodiment 1 is that the coupling agent modified aluminum hydroxide is replaced by an equal amount of coupling agent modified magnesium hydroxide.

[0090] Example 8

[0091] This embodiment provides a high flame retardant polyurethane material and its preparation method. The difference from Embodiment 1 is that the coupling agent modified aluminum hydroxide is replaced by an equal amount of unmodified aluminum hydroxide.

[0092] Example 9

[0093] This embodiment provides a high flame retardant polyurethane material and its preparation method. The difference from Embodiment 1 is that ammonium polyphosphate is replaced with an equal amount of ammonium phosphate salt.

[0094] Example 10

[0095] This embodiment provides a high flame retardant polyurethane material and its preparation method. The difference from Embodiment 1 is that tris(2-chloropropyl) phosphate is replaced with tris(2-chloroethyl) phosphate in equal amounts.

[0096] Example 11

[0097] This embodiment provides a high flame retardant polyurethane material and its preparation method. The difference from Embodiment 1 is that the coupling agent modified aluminum hydroxide is adjusted to 1.6 parts by weight, ammonium polyphosphate to 1.2 parts by weight, and tri(2-chloropropyl) phosphate to 1.2 parts by weight, with a mass ratio of 1:0.75:0.75.

[0098] Example 12

[0099] This embodiment provides a high flame retardant polyurethane material and its preparation method. The difference from Embodiment 1 is that the coupling agent modified aluminum hydroxide is adjusted to 0.7 parts by weight, ammonium polyphosphate to 1.65 parts by weight, and tris(2-chloropropyl) phosphate to 1.6 parts by weight, with a mass ratio of 1:2.36:2.36.

[0100] Example 13

[0101] This embodiment provides a high flame retardant polyurethane material and its preparation method. The difference from Embodiment 1 is that the amount of coupling agent modified aluminum hydroxide is adjusted to 2 parts by weight, the amount of ammonium polyphosphate is 1 part by weight, and the amount of tri(2-chloropropyl) phosphate is 1 part by weight, with a mass ratio of 1:0.5:0.5.

[0102] Example 14

[0103] This embodiment provides a high flame retardant polyurethane material and its preparation method. The difference from Embodiment 1 is that the coupling agent modified aluminum hydroxide is adjusted to 0.6 parts by weight, ammonium polyphosphate to 1.7 parts by weight, and tris(2-chloropropyl) phosphate to 1.7 parts by weight, with a mass ratio of 1:2.8:2.8.

[0104] Comparative Example 1

[0105] This comparative example provides a high flame retardant polyurethane material and its preparation method. The difference from Example 1 is that the raw materials for preparing the high flame retardant polyurethane material do not contain coupling agent modified aluminum hydroxide, and the ammonium polyphosphate and tris(2-chloropropyl) phosphate are adjusted to 2 parts by weight.

[0106] Comparative Example 2

[0107] This comparative example provides a high flame-retardant polyurethane material and its preparation method. The difference from Example 1 is that the raw materials for preparing the high flame-retardant polyurethane material do not contain ammonium polyphosphate, the coupling agent modified aluminum hydroxide is adjusted to 1.6 parts by weight, and the tris(2-chloropropyl) phosphate is 2.4 parts by weight.

[0108] Comparative Example 3

[0109] This comparative example provides a high flame-retardant polyurethane material and its preparation method. The difference from Example 1 is that the raw materials for preparing the high flame-retardant polyurethane material do not contain tris(2-chloropropyl) phosphate, and the coupling agent modified aluminum hydroxide is adjusted to 1.6 parts by weight and ammonium polyphosphate to 2.4 parts by weight.

[0110] Comparative Example 4

[0111] This comparative example provides a high flame-retardant polyurethane material and its preparation method. The difference from Example 1 is that the polymerization inhibitor used in the preparation of the high flame-retardant polyurethane material contains only 4 parts by weight of coupling agent modified aluminum hydroxide.

[0112] Comparative Example 5

[0113] This comparative example provides a high flame retardant polyurethane material and its preparation method. The difference from Example 1 is that the polymerization inhibitor used in the preparation of the high flame retardant polyurethane material contains only 4 parts by weight of ammonium polyphosphate.

[0114] Comparative Example 6

[0115] This comparative example provides a high flame retardant polyurethane material and its preparation method. The difference from Example 1 is that the polymerization inhibitor used in the preparation of the high flame retardant polyurethane material contains only 4 parts by weight of tris(2-chloropropyl) phosphate.

[0116] Test methods

[0117] The high flame-retardant polyurethane materials provided in Examples 1-14 and Comparative Examples 1-6 were subjected to the following tests:

[0118] Vertical burning (UL-94): Tested according to GB 2408-2008;

[0119] Limiting oxygen index: Tested according to GB 2406.2-2009;

[0120] Tensile properties: Tested in accordance with GB / T 528-2009.

[0121] The test results are shown in Table 2 below:

[0122] Table 2

[0123]

[0124] The test results show that:

[0125] (1) As can be seen from Examples 1 to 14, the present invention provides a high flame retardant polyurethane material with an oxygen index of 24.7-28.6% and a V-0 rating of UL-94 standard by reasonably compounding the flame retardant system and designing the formulation of the raw material components for the preparation of polyurethane material. It has excellent flame retardancy, and its tensile strength can reach 25.8-34.0 MPa and its elongation at break can reach 317-360%, which also has excellent mechanical properties.

[0126] (2) As can be seen from Examples 1 and 4-6, the present invention further optimizes the polyol to be a combination of polyethylene glycol and polypropylene glycol. By compounding polyethylene glycol and polypropylene glycol, the mechanical strength and toughness of polyurethane materials can be balanced. If too much polypropylene glycol is added, the strength and hardness of the polyurethane material will be insufficient, lacking support and resulting in poor mechanical properties; moreover, the soft segments of the polyurethane material lack the fixation of the crystalline network, making the material prone to deformation. If too little polypropylene glycol is added, the low-temperature flexibility of the polyurethane material will deteriorate, the hydrolysis resistance will decrease, and the elasticity will decrease.

[0127] (3) As can be seen from Examples 1 and 7-10, the present invention, by further modifying the combined flame retardant system of aluminum hydroxide, ammonium polyphosphate and tri(2-chloropropyl) phosphate with coupling agent, can achieve excellent flame retardant performance while reducing the total amount of flame retardant. Furthermore, reducing the amount of flame retardant added to the resin matrix can avoid the problem of decreased mechanical properties of the resin matrix due to the large amount of flame retardant added.

[0128] (4) As can be seen from Examples 1 and 11-14 and Comparative Examples 1-6, the present invention can achieve better synergistic flame retardant effect by further limiting the mass ratio of the components in the combined flame retardant system of modified aluminum hydroxide, ammonium polyphosphate and tri(2-chloropropyl) phosphate.

[0129] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A highly flame-retardant polyurethane material, characterized in that, The raw materials for preparing the high flame-retardant polyurethane material include polyols, isocyanates, and flame retardants. The flame retardants include modified hydroxides, inorganic phosphorus flame retardants, and phosphate ester flame retardants.

2. The high flame-retardant polyurethane material according to claim 1, characterized in that, The mass ratio of the isocyanate, polyol and flame retardant is 1:(0.8-1.3):(0.3-0.7); Preferably, the mass ratio of the modified hydroxide, inorganic phosphorus flame retardant and phosphate ester flame retardant is 1:(0.75-2.5):(0.75-2.5).

3. The high flame-retardant polyurethane material according to claim 1 or 2, characterized in that, The polyols include polyether polyols; Preferably, the number average molecular weight of the polyether polyol is 500-20000; Preferably, the polyether polyol includes any one or a combination of at least two of polyethylene glycol, polypropylene glycol, or polytetrahydrofuran polyol, and more preferably a combination of polyethylene glycol and polypropylene glycol. Preferably, the mass ratio of polyethylene glycol to polypropylene glycol is (1.2-1.6):

1.

4. The high flame-retardant polyurethane material according to any one of claims 1-3, characterized in that, The isocyanate includes any one or a combination of at least two of diphenylmethane diisocyanate, toluene diisocyanate or isoflurone diisocyanate, preferably diphenylmethane diisocyanate.

5. The high flame-retardant polyurethane material according to any one of claims 1-4, characterized in that, The modified hydroxide is prepared by the following preparation method, the preparation method comprising: The hydroxide, modifier, silane coupling agent, and solvent are mixed and reacted to obtain the modified hydroxide. Preferably, the mass ratio of the hydroxide, modifier, and solvent is 1:(0.01-0.05):(0.5-1.5). Preferably, the hydroxide comprises aluminum hydroxide and / or magnesium hydroxide; Preferably, the modifier includes a silane coupling agent; Preferably, the solvent includes an ethanol solution; Preferably, the reaction is carried out under alkaline conditions; Preferably, the pH value of the alkaline conditions is 5.5-7; Preferably, an alkaline substance is used to adjust the pH value of the reaction; Preferably, the alkaline substance includes ammonia. Preferably, the reaction is carried out under stirring; Preferably, the stirring speed is 400-700 rpm; Preferably, the reaction temperature is 50-60℃ and the reaction time is 1-4 h, for example, it can be 1 h, 2 h, 3 h or 4 h, etc. Preferably, the modified hydroxide includes coupling agent modified aluminum hydroxide and / or coupling agent modified magnesium hydroxide.

6. The high flame-retardant polyurethane material according to any one of claims 1-5, characterized in that, The inorganic phosphorus flame retardant includes any one or a combination of at least two of ammonium polyphosphate, ammonium phosphate salt, calcium phosphate or magnesium phosphate, and is more preferably ammonium polyphosphate. Preferably, the phosphorus content of the phosphate ester flame retardant is 12-14%. Preferably, the phosphate ester flame retardant includes diphosphite flame retardants and / or phenyl phosphate flame retardants, and is preferably a diphosphite flame retardant; Preferably, the diphosphite flame retardant includes any one or a combination of at least two of tris(2-chloropropyl) phosphate, dipentaerythritol diphosphite, tris(2-chloroethyl) phosphate, or tris(2,3-dichloropropyl) phosphate, and more preferably tris(2-chloropropyl) phosphate. Preferably, the flame retardant comprises a combination of coupling agent-modified aluminum hydroxide, ammonium polyphosphate, and tris(2-chloropropyl) phosphate.

7. The high flame-retardant polyurethane material according to any one of claims 1-6, characterized in that, The raw materials for preparing the high flame-retardant polyurethane material also include additives; Preferably, the mass ratio of the isocyanate to the auxiliary agent is 1:(0.03-0.06); Preferably, the additives include mold release agents and / or chain extenders; Preferably, the additives include a release agent and a chain extender in a mass ratio of (6-8):1; Preferably, the release agent comprises fatty alcohol polyoxyethylene ether and / or ethyl lactate; Preferably, the weight-average molecular weight of the fatty alcohol polyoxyethylene ether is 300-600; Preferably, the chain extender comprises any one or a combination of at least two of dimethylthiotoluenediamine, diethanolamine, diethyltoluenediamine, or ethylene glycol.

8. A method for preparing a high flame-retardant polyurethane material as described in any one of claims 1-7, characterized in that, The preparation method of the high flame-retardant polyurethane material includes the following steps: (1) Mix the polyol with optional additives to obtain premix A; Isocyanate was mixed with flame retardant to obtain premix B; (2) Mix premix A and premix B and react to obtain the high flame retardant polyurethane material.

9. The method for preparing the high flame-retardant polyurethane material according to claim 8, characterized in that, The reaction temperature in step (2) is 160-180℃, and the reaction time is 0.5-2 h; Preferably, the reaction in step (2) further includes vacuum degassing; Preferably, the temperature for vacuum degassing is 50-70°C; Preferably, the vacuum degassing time is 20-40 min; Preferably, the vacuum degree of the vacuum degassing is -82 to -89 kPa.

10. The application of a high flame-retardant polyurethane material as described in any one of claims 1-7 in building materials.

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