Graphene polyurethane insulation board and preparation method thereof

Abstract

The invention relates to a graphene polyurethane insulation board and a preparation method thereof, and belongs to the technical field of building materials. The graphene polyurethane insulation board is prepared from the following components in parts by weight: 100 parts of polymethylene polyphenyl polyisocyanate, 40 to 80 parts of polypropylene oxide polyol, 10 to 20 parts of polytetrahydrofuran, 5 to 15 parts of 1, 4-butanediol, 5 to 25 parts of a flame retardant, 10 to 30 parts of a cross-linking agent, 1 to 5 parts of a foaming agent, 1 to 5 parts of an anti-aging agent and 5 to 20 parts of oleoyl sodium methyl taurate, the flame retardant comprises a first flame retardant and a second flame retardant, the first flame retardant comprises one or more of silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate, and the second flame retardant comprises one or more of trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate. According to the polyurethane insulation board, the flame retardant is selected and matched and is matched with the oleoyl sodium methyl taurate, so that the polyurethane insulation board has relatively good water absorption, strength property, thermal insulation property and flame retardant property, and has relatively good market competitiveness.

Description

Technical Field

[0001] The present application relates to a graphene polyurethane thermal insulation board and a preparation method thereof, and belongs to the technical field of building materials. Background Art

[0002] As a common building material used in the construction of building energy-saving and heat-insulating projects, insulation boards can improve the energy-saving and environmental protection performance of buildings. In the prior art, common insulation boards include: soft porcelain insulation materials, aluminum silicate insulation materials, phenolic foam materials, polyurethane foam materials, rubber powder polystyrene particles, rock wool, foamed cement, etc. Among them, inorganic insulation materials have the advantages of low production cost, excellent material anti-aging performance, and small degree of thermal deformation, but inorganic insulation materials have poor impact resistance and are easy to crack under pressure. The cracked insulation materials are easy to fall off and lose their practical value. Among them, the low-priced polystyrene board occupies 70% of the building exterior wall insulation market. Among them, polyurethane material is a thermosetting material. Compared with thermoplastic polystyrene board, it has the advantages of no shrinkage, no melting drop, and no burning through at 1000℃ flame for 20 minutes. It is also fully leading in many aspects such as thermal insulation, corrosion resistance, bonding performance, mechanical properties and service life, and has become a popular choice in current research and application.

[0003] As a lightweight insulation material with high compressive strength and good thermal insulation effect, polyurethane insulation board is often used in building walls, cold storage rooms, chemical tanks and other fields. Since polyurethane insulation board is mostly used in densely populated areas, cargo storage areas and chemical product gathering areas, its fire protection level has high requirements. Polyurethane insulation board not only needs to have thermal insulation performance but also outstanding fire resistance performance.

[0004] The polyurethane insulation board is made by mixing polyether polyol and isocyanate in a certain proportion with amine as catalyst. Due to the inherent defects of ordinary polyurethane, no matter how the amount of flame retardant is changed, its flame retardant performance is difficult to reach a high level. In addition, the polyurethane insulation board also has relatively poor heat resistance and tensile strength, especially in summer when the temperature of the exterior wall can usually reach above 60°C, and the polyurethane insulation board has poor weather resistance to high temperatures in summer, which makes it more prone to aging, and the strength and insulation performance will be reduced. These shortcomings seriously restrict the application of polyurethane insulation boards.

[0005] In order to improve the flame retardant properties of polyurethane insulation boards, it is usually necessary to add reactive flame retardants or non-reactive flame retardants to the polyurethane insulation boards to achieve the flame retardant effect. However, there is still the problem of poor compatibility between flame retardants and polyurethane resulting in poor flame retardant effect. In addition, its thermal insulation performance, thermal conductivity, and waterproof and anti-seepage properties still need to be further improved. Summary of the invention

[0006] In order to solve the above problems, a graphene polyurethane insulation board and a preparation method thereof are provided. By selecting and matching the flame retardant, and when it is combined with sodium oleoyl methyl taurate, it has good compatibility in the polyurethane matrix, thereby significantly improving the flame retardant performance. In addition, by selecting polyoxypropylene polyol with specific properties, and combining it with polytetrahydrofuran and 1,4-butanediol, when reacting with polymethylene polyphenyl polyisocyanate, the pore uniformity is higher, and the obtained insulation board has better strength performance. The polyurethane insulation board of the present application has good water absorption, strength performance, thermal insulation performance and flame retardant performance, so that it has good market competitiveness.

[0007] The present application provides a graphene polyurethane insulation board, which comprises the following components by weight: 100 parts of polymethylene polyphenyl polyisocyanate, 40-80 parts of polyoxypropylene polyol, 10-20 parts of polytetrahydrofuran, 5-15 parts of 1,4-butanediol, 5-25 parts of flame retardant, 10-30 parts of crosslinking agent, 1-5 parts of foaming agent, 1-5 parts of antioxidant and 5-20 parts of sodium oleoyl methyl taurate; The flame retardant includes a first flame retardant and a second flame retardant, the first flame retardant includes one or more of silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate, and the second flame retardant includes one or more of trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate.

[0008] Optionally, the flame retardant includes a first flame retardant and a second flame retardant, and the mass ratio of the first flame retardant to the second flame retardant is (1-2): (1-2); The first flame retardant comprises silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate, and the mass ratio of the silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate is (20-40): (5-10): (1-5); The second flame retardant includes trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate, and the mass ratio of trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate is (1-3): (1-3): (1-3).

[0009] Optionally, the method for preparing the silane coupling agent modified graphene oxide comprises the following steps: S1, adding graphene oxide to a solvent and performing ultrasonic dispersion to obtain a graphene oxide suspension; S2. Adjust the pH value to 5.0~5.5; S3, adding a silane coupling agent to the graphene oxide suspension; S4, stirring the reaction for at least 3 hours to obtain silane coupling agent-modified graphene oxide; The silane coupling agent is selected from one or more of KH550, KH560, KH570, KH792, DL602 and DL171, and the mass ratio of the silane coupling agent to the graphene oxide is (10-20):1.

[0010] Optionally, the solvent in step S1 is ethanol aqueous solution; Optionally, the volume ratio of ethanol to water is (1-5):(1-5).

[0011] Optionally, in step S2, acetic acid is used to adjust the pH to 5.0-5.5.

[0012] Optionally, the graphene oxide powder has a flake diameter of 30-50 μm, a thickness of 1-2 nm, and a carbon content of 60-80 wt%.

[0013] Optionally, the functionality of the polyoxypropylene polyol is 5-6, and the hydroxyl value is 60-80 mg KOH / g.

[0014] Optionally, 1 to 5 parts of a heat stabilizer are also included; The heat stabilizer is selected from one or both of tridecyl phosphite and trioctyl phosphite.

[0015] Optionally, the heat stabilizer includes tridecyl phosphite and trioctyl phosphite; Optionally, the weight ratio of tridecyl phosphite to trioctyl phosphite is (8-10):(1-2).

[0016] Optionally, the foaming agent is selected from one or more of dichloromethane, dichloroethane and cyclopentane; and / or, The cross-linking agent is selected from one or both of diethanolamine and triethylenediamine.

[0017] The present application also provides a method for preparing the above-mentioned graphene polyurethane insulation board, the preparation method comprising the following steps: 1) Weigh and prepare all raw materials; 2) uniformly mixing the other raw materials except polymethylene polyphenyl polyisocyanate; 3) Add polymethylene polyphenyl polyisocyanate and stir for 30 to 180 seconds; 4) Place the material in the mold and let it stand; 5) After aging at 90-120° C., the graphene polyurethane insulation board is obtained.

[0018] Optionally, in step 5), the treatment time at 90-120° C. is 40-100 min.

[0019] Optionally, in the step 2) of mixing, a high-speed disperser is used for dispersion treatment, and the dispersion treatment is performed at a speed of not less than 2000 rps for not less than 20 minutes.

[0020] The beneficial effects of this application include but are not limited to: 1. According to the graphene polyurethane insulation board and preparation method thereof of the present application, by selecting a first flame retardant and a second flame retardant for synergistic combination, wherein the first flame retardant is a solid flame retardant and the second flame retardant is a liquid flame retardant, and by adding sodium oleyl methyl taurate for combination, the compatibility of the flame retardant in the polyurethane system can be significantly improved, thereby significantly improving the flame retardant properties of the insulation board.

[0021] 2. According to the graphene polyurethane thermal insulation board and its preparation method of the present application, polyoxypropylene polyol with specific performance is selected to cooperate with polytetrahydrofuran and 1,4-butanediol, and when cross-linking reaction is carried out with polymethylene polyphenyl polyisocyanate, the foaming effect can be improved, so that the uniformity of the foam cells produced by foaming is better, in addition to significantly improving the thermal insulation performance of the thermal insulation board, the strength of the thermal insulation board is also improved, and the water absorption rate is also reduced.

[0022] 3. According to the graphene polyurethane insulation board and its preparation method of the present application, by modifying the added graphene oxide and selecting graphene oxide with specific properties as the preparation raw material, the dispersion performance of graphene oxide in the polyurethane group can be significantly improved, and the thermal insulation performance and flame retardant performance of the insulation board are improved.

[0023] 4. According to the graphene polyurethane insulation board and preparation method thereof of the present application, by adding a heat stabilizer, the uniformity of the pores formed during the foaming preparation process can be further improved, and the comprehensive performance of the insulation board can be further improved.

[0024] 5. According to the graphene polyurethane insulation board and preparation method of the present application, by optimizing the material of the polyurethane matrix, using polyoxypropylene polyol with polytetrahydrofuran and 1,4-butanediol, and cross-linking reaction with polymethylene polyphenyl polyisocyanate, and adding a heat stabilizer, the prepared polyurethane insulation board has good high-temperature weather resistance, can reduce aging caused by high temperature, and reduce the rate at which the thermal insulation performance and strength performance of the polyurethane insulation board decrease with time and high-temperature aging. DETAILED DESCRIPTION

[0025] The present application is described in detail below in conjunction with examples, but the present application is not limited to these examples. Unless otherwise specified, the raw materials and reagents in the examples of the present application are purchased through commercial channels.

[0026] The present application scheme is described below through specific embodiments.

[0027] Example 1 This embodiment provides a graphene polyurethane insulation board, which includes the following components in parts by weight: 100 parts of polymethylene polyphenyl polyisocyanate, 60 parts of polyoxypropylene polyol, 15 parts of polytetrahydrofuran, 10 parts of 1,4-butanediol, 15 parts of flame retardant, 20 parts of cross-linking agent, 3 parts of foaming agent, 3 parts of antioxidant and 12 parts of sodium oleyl methyl taurate; the flame retardant includes a first flame retardant and a second flame retardant, and the mass ratio of the first flame retardant to the second flame retardant is 1:1; the first flame retardant includes silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate, and the mass ratio of the silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate is 30:8:3; the second flame retardant includes trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate, and the mass ratio of trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate is 1:1:1.

[0028] The functionality of the polyoxypropylene polyol is 5, and the hydroxyl value is 70 mg KOH / g; the foaming agent is dichloromethane; and the cross-linking agent is diethanolamine.

[0029] The method for preparing silane coupling agent modified graphene oxide comprises the following steps: S1, adding graphene oxide to a solvent and performing ultrasonic dispersion to obtain a graphene oxide suspension; S2, adjust the pH value to 5.3; S3, adding a silane coupling agent to the graphene oxide suspension; S4, stirring and reacting for 3 hours to obtain silane coupling agent-modified graphene oxide; The silane coupling agent is KH550, and the mass ratio of the silane coupling agent to graphene oxide is 15:1; the flake diameter of the graphene oxide powder is 30-50 μm, the thickness is 1-2 nm, and the carbon content is 70 wt%.

[0030] The preparation method of the graphene polyurethane thermal insulation board comprises the following steps: 1) Weigh and prepare all raw materials; 2) uniformly mixing the other raw materials except polymethylene polyphenyl polyisocyanate, and specifically using a high-speed disperser for dispersion treatment at a speed of 2000 rps for 20 minutes; 3) Add polymethylene polyphenyl polyisocyanate and stir for 100 seconds; 4) Place the material in the mold and let it stand; 5) After aging at 105°C for 70 minutes, a graphene polyurethane insulation board was obtained.

[0031] Example 2 This embodiment provides a graphene polyurethane insulation board, which includes the following components in parts by weight: 100 parts of polymethylene polyphenyl polyisocyanate, 40 parts of polyoxypropylene polyol, 10 parts of polytetrahydrofuran, 5 parts of 1,4-butanediol, 5 parts of flame retardant, 10 parts of cross-linking agent, 1 part of foaming agent, 1 part of antioxidant and 5 parts of sodium oleyl methyl taurate; the flame retardant includes a first flame retardant and a second flame retardant, and the mass ratio of the first flame retardant to the second flame retardant is 1:2; the first flame retardant includes silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate, and the mass ratio of the silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate is 20:5:1; the second flame retardant includes trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate, and the mass ratio of trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate is 1:3:1.

[0032] The functionality of the polyoxypropylene polyol is 6, and the hydroxyl value is 60 mg KOH / g; the foaming agent is cyclopentane; and the cross-linking agent is diethanolamine.

[0033] The method for preparing silane coupling agent modified graphene oxide comprises the following steps: S1, adding graphene oxide to a solvent and performing ultrasonic dispersion to obtain a graphene oxide suspension; S2, adjust the pH value to 5.0; S3, adding a silane coupling agent to the graphene oxide suspension; S4, stirring and reacting for 4 hours to obtain silane coupling agent-modified graphene oxide; The silane coupling agent is KH560, and the mass ratio of the silane coupling agent to the graphene oxide is 10:1; the flake diameter of the graphene oxide powder is 30-50 μm, the thickness is 1-2 nm, and the carbon content is 60 wt%.

[0034] The preparation method of the graphene polyurethane thermal insulation board comprises the following steps: 1) Weigh and prepare all raw materials; 2) uniformly mixing the other raw materials except polymethylene polyphenyl polyisocyanate, and specifically using a high-speed disperser for dispersion treatment at a speed of 2000 rps for 30 minutes; 3) Add polymethylene polyphenyl polyisocyanate and stir for 30 seconds; 4) Place the material in the mold and let it stand; 5) After aging at 90°C for 100 min, a graphene polyurethane insulation board was obtained.

[0035] Example 3 This embodiment provides a graphene polyurethane insulation board, which includes the following components in parts by weight: 100 parts of polymethylene polyphenyl polyisocyanate, 80 parts of polyoxypropylene polyol, 20 parts of polytetrahydrofuran, 15 parts of 1,4-butanediol, 25 parts of flame retardant, 30 parts of cross-linking agent, 5 parts of foaming agent, 5 parts of antioxidant and 20 parts of sodium oleyl methyl taurate; the flame retardant includes a first flame retardant and a second flame retardant, and the mass ratio of the first flame retardant to the second flame retardant is 2:1; the first flame retardant includes silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate, and the mass ratio of the silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate is 40:10:5; the second flame retardant includes trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate, and the mass ratio of trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate is 3:1:1.

[0036] The functionality of the polyoxypropylene polyol is 5, and the hydroxyl value is 80 mg KOH / g; the foaming agent is ethylene dichloride; and the cross-linking agent is triethylene diamine.

[0037] The method for preparing silane coupling agent modified graphene oxide comprises the following steps: S1, adding graphene oxide to a solvent and performing ultrasonic dispersion to obtain a graphene oxide suspension; S2, adjust the pH value to 5.5; S3, adding a silane coupling agent to the graphene oxide suspension; S4, stirring and reacting for 5 hours to obtain silane coupling agent-modified graphene oxide; The silane coupling agent is KH570, and the mass ratio of the silane coupling agent to the graphene oxide is 20:1; the flake diameter of the graphene oxide powder is 30-50 μm, the thickness is 1-2 nm, and the carbon content is 80 wt%.

[0038] The preparation method of the graphene polyurethane thermal insulation board comprises the following steps: 1) Weigh and prepare all raw materials; 2) uniformly mixing the other raw materials except polymethylene polyphenyl polyisocyanate, and specifically using a high-speed disperser for dispersion treatment at a speed of 2500 rps for 20 minutes; 3) Add polymethylene polyphenyl polyisocyanate and stir for 180 seconds; 4) Place the material in the mold and let it stand; 5) After aging at 120°C for 40 min, a graphene polyurethane insulation board was obtained.

[0039] Example 4 This embodiment is substantially the same as the embodiment 1, except that it further comprises 1 part of a heat stabilizer, which is tridecyl phosphite.

[0040] Example 5 This embodiment is substantially the same as the embodiment 1, except that it further comprises 5 parts of a heat stabilizer, which is trioctyl phosphite.

[0041] Example 6 This embodiment is substantially the same as embodiment 1, except that the silane coupling agent-modified graphene oxide is replaced by an equal amount of graphene oxide.

[0042] Example 7 This embodiment is substantially the same as Embodiment 1, except that, in the method for preparing graphene oxide modified with a silane coupling agent, the mass ratio of the silane coupling agent to the graphene oxide is 8:1.

[0043] Example 8 This embodiment is substantially the same as Embodiment 1, except that, in the method for preparing graphene oxide modified by a silane coupling agent, the flake diameter of the graphene oxide powder is 20-25 μm.

[0044] Example 9 This embodiment is substantially the same as embodiment 1, except that, in the method for preparing graphene oxide modified by a silane coupling agent, the carbon content is 90 wt %.

[0045] Example 10 This example is substantially the same as Example 1, except that the functionality of the polyoxypropylene polyol is 3 and the hydroxyl value is 40 mg KOH / g.

[0046] Comparative Example 1 This comparative example is substantially the same as Example 1, except that it does not contain sodium oleoyl methyl taurate.

[0047] Comparative Example 2 This comparative example is substantially the same as Example 1, except that sodium oleoyl methyl taurate is replaced by an equal amount of polyoxyethylene lauryl ether phosphate salt.

[0048] Comparative Example 3 This comparative example is substantially the same as Example 1, except that sodium oleoyl methyl taurate is replaced by an equal amount of sodium α-olefin sulfonate.

[0049] Comparative Example 4 This comparative example is basically the same as Example 1, except that sodium oleoyl methyl taurate is replaced by an equal amount of fatty alcohol polyoxyethylene ether sulfate.

[0050] Comparative Example 5 This comparative example is substantially the same as Example 1, except that the flame retardant only includes the first flame retardant.

[0051] Comparative Example 6 This comparative example is substantially the same as Example 1, except that the flame retardant only includes the second flame retardant.

[0052] Comparative Example 7 This comparative example is substantially the same as Example 1, except that polytetrahydrofuran is not contained.

[0053] Comparative Example 8 This comparative example is substantially the same as Example 1, except that 1,4-butanediol is not contained.

[0054] Test Example 1 The following performance tests were performed on the polyurethane thermal insulation boards obtained in Examples 1 to 10 and Comparative Examples 1 to 8.

[0055] Thermal conductivity: Thermal conductivity (W / mk) is tested according to GB / T10294.

[0056] Water absorption: Water absorption (%) is tested according to GB / T 8810-2005.

[0057] Compression strength: Compression strength (MPa) is tested according to GB / T21558-2008.

[0058] Dimensional stability: The linear shrinkage rate (%) is tested according to GB / T 8811-2008 to characterize the dimensional stability.

[0059] Limiting oxygen index: The combustion performance is tested in accordance with GB8624-2012, and the limiting oxygen index (%) is tested. The installation of the combustion specimen is in accordance with GB / T20284-2006.

[0060] Cell size range: Take samples after cutting the polyurethane insulation board, measure and record the size range (μm) of the cells within the sampling range.

[0061] The test results are shown in Table 1. In Table 1, the greater the thermal conductivity, the worse the thermal insulation performance of the insulation board; the greater the water absorption, the more serious the water absorption of the insulation board; the greater the compression strength, the better the strength of the insulation board; the smaller the linear shrinkage, the better the dimensional stability of the insulation board; the higher the limiting oxygen index, the better the flame retardant performance of the insulation board; the narrower the range of pore size, the smaller the difference in bubble size, the more uniform the pore size, and the better the foaming effect.

[0062] Table 1 Performance test results of polyurethane insulation board

[0063] According to the results in Table 1, Examples 1 to 3 have good water absorption, strength, thermal insulation and flame retardancy, and good cell uniformity. Examples 4 and 5 can further improve the cell uniformity by adding a heat stabilizer, and have a significant effect on improving water absorption, strength, thermal insulation and flame retardancy.

[0064] According to the results of Examples 6, 7, 8 and 9, in the present application, by selecting graphene oxide with specific properties and performing modification treatment, the dispersion performance of graphene oxide in polyurethane can be significantly improved, showing a more obvious improvement effect on flame retardancy and thermal insulation performance.

[0065] According to the results of Example 10, the polyoxypropylene polyol with specific properties used in the present application scheme, in combination with polymethylene polyphenyl polyisocyanate, can obtain a polyurethane insulation board with better thermal insulation effect and better strength performance, and the water absorption rate of the insulation board is also lower.

[0066] According to the results of Comparative Examples 1, 2, 3 and 4, in the present application, due to the combination of the first flame retardant and the second flame retardant, the compatibility of the two flame retardants in the polyurethane matrix is ​​significantly improved under the action of sodium oleoyl methyl taurate. Compared with other surfactants, sodium oleoyl methyl taurate shows significantly better system compatibility.

[0067] According to the results of Comparative Examples 5 and 6, the flame retardant in the polyurethane is selected in the present application, specifically a liquid flame retardant and a solid flame retardant are selected for synergistic combination, and the flame retardant effect is significantly improved by combining sodium oleyl methyl taurate with a polyurethane matrix, while the flame retardant system in Comparative Examples 5 and 6 has a poor effect.

[0068] According to the results of Comparative Examples 7 and 8, in the present application, the addition of polytetrahydrofuran and 1,4-butanediol in combination with polyoxypropylene polyols having characteristic properties can significantly improve the foaming effect and the uniformity of the pores in the process of cross-linking polyurethane to form polyurethane. The strength performance of the polyurethane insulation board is also significantly improved. Moreover, due to the higher uniformity of the pores, the pores at the edge of the insulation board will not be too large, so that the water absorption rate is also significantly reduced.

[0069] The above is only the embodiment of the present application, and the protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the technical ideas and principles of the present application should be included in the protection scope of the present application.

Claims

1. A graphene polyurethane insulation board, characterized in that: The graphene polyurethane insulation board comprises the following components in parts by weight: 100 parts of polymethylene polyphenyl polyisocyanate, 40-80 parts of polyoxypropylene polyol, 10-20 parts of polytetrahydrofuran, 5-15 parts of 1,4-butanediol, 5-25 parts of flame retardant, 10-30 parts of crosslinking agent, 1-5 parts of foaming agent, 1-5 parts of antioxidant and 5-20 parts of sodium oleoyl methyl taurate; The flame retardant includes a first flame retardant and a second flame retardant, the first flame retardant includes one or more of silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate, and the second flame retardant includes one or more of trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate.

2. The graphene polyurethane insulation board according to claim 1, characterized in that: The flame retardant comprises a first flame retardant and a second flame retardant, and the mass ratio of the first flame retardant to the second flame retardant is (1-2): (1-2); The first flame retardant comprises silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate, and the mass ratio of the silane coupling agent modified graphene oxide, ammonium hydrogen phosphate and zinc aluminate is (20-40): (5-10): (1-5); The second flame retardant includes trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate, and the mass ratio of trichloroethyl phosphate, dimethyl methylphosphonate and diphenyl isooctyl phosphate is (1-3): (1-3): (1-3).

3. The graphene polyurethane insulation board according to claim 2, characterized in that: The preparation method of the silane coupling agent modified graphene oxide comprises the following steps: S1, adding graphene oxide to a solvent and performing ultrasonic dispersion to obtain a graphene oxide suspension; S2. Adjust the pH value to 5.0~5.5; S3, adding a silane coupling agent to the graphene oxide suspension; S4, stirring the reaction for at least 3 hours to obtain silane coupling agent-modified graphene oxide; The silane coupling agent is selected from one or more of KH550, KH560, KH570, KH792, DL602 and DL171, and the mass ratio of the silane coupling agent to the graphene oxide is (10-20):

1.

4. The graphene polyurethane insulation board according to claim 3, characterized in that: The graphene oxide powder has a sheet diameter of 30-50 μm, a thickness of 1-2 nm, and a carbon content of 60-80 wt%.

5. The graphene polyurethane insulation board according to claim 1, characterized in that: The functionality of the polyoxypropylene polyol is 5-6, and the hydroxyl value is 60-80 mg KOH / g.

6. The graphene polyurethane insulation board according to claim 1, characterized in that: Also includes 1 to 5 parts of heat stabilizer; The heat stabilizer is selected from one or both of tridecyl phosphite and trioctyl phosphite.

7. The graphene polyurethane insulation board according to claim 1, characterized in that: The foaming agent is selected from one or more of dichloromethane, dichloroethane and cyclopentane; and / or, The cross-linking agent is selected from one or both of diethanolamine and triethylenediamine.

8. The method for preparing the graphene polyurethane thermal insulation board according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: 1) Weigh and prepare all raw materials; 2) uniformly mixing the other raw materials except polymethylene polyphenyl polyisocyanate; 3) Add polymethylene polyphenyl polyisocyanate and stir for 30 to 180 seconds; 4) Place the material in the mold and let it stand; 5) After aging at 90-120° C., the graphene polyurethane insulation board is obtained.

9. The method for preparing the graphene polyurethane thermal insulation board according to claim 8, characterized in that: In the step 5), the treatment time at 90-120° C. is 40-100 min.

10. The method for preparing the graphene polyurethane thermal insulation board according to claim 8, characterized in that: In the step 2) of mixing, a high-speed disperser is used for dispersion treatment at a speed of not less than 2000 rps for not less than 20 minutes.

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