Composite flame retardant for insulation board and insulation board containing composite flame retardant

Abstract

The invention discloses a composite flame retardant for an insulation board and the insulation board containing the composite flame retardant, and belongs to the technical field of insulation boards. The material comprises a modified graphene oxide coated inorganic flame retardant and an N-series flame retardant in a weight ratio of 1: (1.5-3), the preparation method of the modified graphene oxide coated inorganic flame retardant comprises the following steps: S1, adding graphene oxide into an aqueous solution, and uniformly mixing to obtain a graphene oxide solution; s2, adding an inorganic flame retardant into the graphene oxide solution to obtain a solution containing the graphene oxide coated inorganic flame retardant; s3, under inert gas, fluorine-containing trichlorosilane and an acid-binding agent are added into the solution obtained in the step S2, modification is conducted for 1-3 h at the temperature of 50-80 DEG C, and an intermediate A is obtained after filtering and drying; and adding the intermediate A into an alcohol amine solution, reacting at 80-100 DEG C for 12-15 hours, filtering, and drying to obtain the modified graphene oxide coated inorganic flame retardant. The composite flame retardant is high in dispersity and compatibility in a polyurethane material, and relatively high in flame retardant property, mechanical property and waterproof property.

Description

Technical Field

[0001] This application relates to a composite flame retardant for insulation boards and an insulation board containing the same, belonging to the technical field of insulation boards. Background Technology

[0002] Flame retardants are functional additives that impart flame-retardant properties to flammable polymers. Currently, most of the materials used in the preparation of insulation boards are polyurethane, but polyurethane has a low safety factor in flame retardancy. Therefore, by preparing flame retardants for insulation boards, the flame retardant performance and safety factor of insulation boards can be improved.

[0003] Most existing flame retardants are produced by adding flame retardants. Adding flame retardants can improve the mechanical properties and flame retardant effect of polyurethane materials. However, to achieve a good flame retardant effect, the amount added must be large. A large amount not only affects other performance indices of polyurethane, but also has drawbacks such as easy precipitation of flame retardants and decreased flame retardant effect with long-term use. Alternatively, compounds containing flame retardant elements and active groups are used as reactive flame retardants. Reactive flame retardants introduce flame retardant elements or flame retardant groups into the structure of polymer materials through chemical reactions, thereby giving the polymer materials flame retardant properties. This method has the advantages of good flame retardant effect and less impact on the physical and mechanical properties of insulation boards, but it has problems such as complex production process and high product viscosity.

[0004] Chinese invention patent CN 109608817 A discloses a flame retardant for fireproof insulation boards, comprising thermosetting resin, inorganic powder, elastic toughening agent, waterproofing agent, curing agent, and water. The prepared flame retardant has good ablation resistance, low smoke toxicity, low thermal conductivity, good flame retardancy, good weather resistance, and low environmental pollution. It is an environmentally friendly flame retardant with a fire rating of A2. However, when the above-mentioned flame retardant is added to the insulation board as an additive, its compatibility with polyurethane materials is poor, which results in poor durability of the flame retardant properties of the insulation board. Summary of the Invention

[0005] To address the aforementioned issues, a composite flame retardant for insulation boards is provided. In this application, modified graphene oxide-coated inorganic flame retardants and N-based flame retardants are compounded in a specific ratio to obtain the composite flame retardant for insulation boards. By using graphene oxide to coat the inorganic flame retardant, the dispersion effect of the inorganic flame retardant is improved. Modifying the graphene oxide-coated inorganic flame retardant can improve its dispersibility and compatibility in polyurethane materials, thereby enhancing the flame retardant and mechanical properties of the insulation board and solving the technical problem of insulation board safety.

[0006] According to one aspect of this application, a composite flame retardant for insulation boards is provided, comprising a modified graphene oxide-coated inorganic flame retardant and an N-series flame retardant in a weight ratio of 1:(0.5-1).

[0007] The preparation method of the modified graphene oxide-coated inorganic flame retardant is as follows:

[0008] S1 Preparation of graphene oxide solution: Add graphene oxide to an aqueous solution and mix thoroughly to obtain a graphene oxide solution;

[0009] S2 Preparation of graphene oxide-coated inorganic flame retardant: Add graphene oxide solution to inorganic flame retardant to obtain a solution containing graphene oxide-coated inorganic flame retardant;

[0010] S3 Preparation of modified graphene oxide-coated inorganic flame retardant: Under inert gas conditions, add fluorinated trichlorosilane and an acid-binding agent to the solution containing graphene oxide-coated inorganic flame retardant obtained in step S2, modify at 50-80℃ for 1-3 hours, filter and dry to obtain intermediate A; then add intermediate A to an alkanolamine solution, react at 20-40℃ for 12-15 hours, filter and dry to obtain modified graphene oxide-coated inorganic flame retardant.

[0011] This application employs a modified graphene oxide-coated inorganic flame retardant and an N-based flame retardant to obtain a composite flame retardant for insulation boards. This composite flame retardant synergistically improves the flame retardant performance of the insulation board. Simultaneously, the addition of the inorganic flame retardant fills the voids in the insulation board substrate, enhancing both its flame retardant effect and mechanical properties. Furthermore, graphene oxide possesses an extremely large specific surface area, which facilitates improved compatibility between the inorganic flame retardant and polymer materials. It also forms a large-area barrier layer, blocking heat transfer. The addition of an N-based flame retardant to the composite flame retardant achieves a synergistic flame retardant effect, and these substances achieve a stable mixture state within the material, resisting sedimentation and agglomeration, thus effectively improving the material's mechanical and flame retardant properties.

[0012] This application further utilizes graphene oxide to coat inorganic flame retardants, which effectively improves the dispersibility of inorganic flame retardants in the insulation board substrate and prevents their agglomeration, thereby enhancing the mechanical uniformity of the insulation board. Furthermore, modifying the graphene oxide coating with fluorinated trichlorosilane and alkanolamines improves the flame retardant and waterproof properties of the composite flame retardant. This not only improves the performance of the insulation material but also reduces the amount of inorganic flame retardant used, preventing excessive addition from negatively impacting the quality of the insulation material. Modifying the graphene oxide coated with inorganic flame retardants allows for a reaction between the amine groups on the alkanolamine and the isocyanate groups, a raw material for polyurethane synthesis, improving the compatibility between graphene oxide and the insulation board substrate, thus enhancing the flame retardant performance of the insulation board.

[0013] Optionally, the fluorinated trichlorosilane in S3 has the structural formula shown in formula (1).

[0014]

[0015] R1 is selected from one of perfluorooctyl, perfluorohexyl, and perfluorododecyl.

[0016] This application selects fluorinated trichlorosilane to modify the graphene oxide-coated inorganic flame retardant. Firstly, the fluorine atoms in the fluorinated trichlorosilane molecule can react with free radicals during combustion to form stable fluorides, consuming the free radicals and interrupting the chain reaction of combustion, thereby inhibiting the combustion reaction and reducing its intensity. Secondly, when fluorinated trichlorosilane decomposes at high temperatures, it produces inert gases, such as small molecules containing chlorine and fluorine, reducing the oxygen content in the combustion zone and making combustion difficult to sustain, thus improving the flame retardant performance of the insulation board. Finally, fluorinated trichlorosilane can decompose at high temperatures to generate silica and other byproducts. These products can form a dense protective layer on the surface of the insulation board, isolating oxygen and preventing the spread of flames. Simultaneously, the protective layer can prevent heat transfer to the interior of the material, thereby reducing the combustion rate.

[0017] This application selects one of perfluorooctyltrichlorosilane, perfluorohexyltrichlorosilane, and perfluorododecyltrichlorosilane because perfluorinated compounds have extremely low surface energy. Introducing them into polyurethane can significantly improve the hydrophobic and oleophobic properties of the material, thereby enhancing its antifouling, waterproofing, and oil-repellent capabilities. Simultaneously, perfluorinated compounds possess excellent chemical stability and heat resistance. Due to the strong electronegativity and high CF bond energy of fluorine atoms, polyurethane containing perfluorinated groups exhibits stronger stability in the face of various chemical media, is less susceptible to corrosion or dissolution, and improves the chemical corrosion resistance and durability of polyurethane materials. More preferably, perfluorododecyltrichlorosilane is preferred. Perfluorododecyl contains long-chain alkyl groups, which synergistically enhance waterproofing performance with fluorine atoms, resulting in superior waterproofing. Furthermore, the weak intermolecular forces of perfluorododecyl molecules make the surface of polyurethane materials containing perfluorododecyl smoother, which not only improves the flame retardant and waterproofing properties of polyurethane materials but also enhances the material's feel and friction resistance.

[0018] Optionally, the weight ratio of graphene oxide to fluorinated trichlorosilane is 1:(0.3-0.5).

[0019] At this ratio, the hydroxyl groups on graphene oxide can undergo substitution reactions with fluorinated trichlorosilanes, enabling effective reaction between the two. Due to the larger size of the graphene oxide groups, the graphene oxide reacts with one or two chloro-silicon bonds on the fluorinated trichlorosilane. Because of steric hindrance, at least one chloro-silicon bond will remain on the fluorinated trichlorosilane. This ensures that the chloro-silicon bond reacts with the alkanolamine, thereby introducing functional groups again into the modified graphene oxide coating of inorganic flame retardants, improving the overall performance of the flame retardant.

[0020] Optionally, the amine in S3 is one or more of N-benzylethanolamine, N-cyclohexylethanolamine, and N-phenylethanolamine.

[0021] The alkanolamines used in this application all contain cyclic groups and alkanolamine groups. The introduction of benzyl groups can significantly increase the maximum thermal decomposition temperature of the insulation board, thereby improving the hot air stability of the insulation board. The introduction of phenyl groups can make the polyurethane insulation board have better thermal stability. Under high temperature environment, phenyl groups can effectively inhibit the thermal degradation and oxidation reaction of molecular chains. On the one hand, the steric hindrance effect of phenyl groups can hinder the contact between oxygen molecules and polyurethane molecular chains, slowing down the rate of oxidative degradation. On the other hand, the conjugated system of phenyl groups can absorb some heat and reduce the thermal motion activity of molecular chains.

[0022] The hydroxyl group in the alkanolamine group undergoes a substitution reaction with at least one chlorosilane bond remaining on the chlorosilane, causing the alkanolamine containing a benzene ring to be added to intermediate A, thus obtaining a modified graphene oxide-coated inorganic flame retardant containing amine and perfluorinated groups. Due to the presence of the amine group, the flame retardant participates in the polymerization reaction during the polyurethane insulation board reaction, realizing the reaction between the flame retardant and the polyurethane material. This allows the composite flame retardant to extend the flame retardant effect of the insulation board, while also improving the dispersion and characterization of the flame retardant in the polyurethane substrate, enhancing the flame retardant effect, and extending the service life of the insulation board.

[0023] Optionally, the concentration of the graphene oxide solution in S1 is 0.5-1.2%.

[0024] When graphene oxide concentration is below 0.5%, it cannot form a sufficient coating layer, resulting in ineffective encapsulation of inorganic flame retardants and thus a weak flame-retardant effect. Furthermore, low concentrations of graphene oxide are difficult to disperse uniformly in aqueous solutions, affecting subsequent modification processes and consequently its distribution and flame-retardant performance within the substrate. While higher concentrations of graphene oxide above 1.2% provide better coverage, excessively high concentrations can lead to solution instability, agglomeration, and ineffective encapsulation of inorganic flame retardants, while also affecting its dispersibility and flame-retardant properties within the substrate. A graphene oxide concentration between 0.5% and 1.2% ensures effective encapsulation of inorganic flame retardants and allows for the formation of a uniform and dense coating layer on the substrate surface.

[0025] Optionally, the inorganic flame retardant in S2 is one or more of aluminum hydroxide, magnesium hydroxide, and antimony trioxide.

[0026] Optionally, the N-series flame retardant is one or more of melamine, dicyandiamide, and melamine cyanurate. At high temperatures, the N-series flame retardant decomposes to produce non-flammable gases such as nitrogen, diluting the concentration of oxygen and flammable gases. It may also promote the formation of a char layer on the polymer surface, acting as an air barrier and preventing heat transfer. The synergistic effect of the N-series flame retardant and inorganic flame retardants more effectively reduces the surface temperature of polyurethane, inhibits combustion reactions, and reduces the concentration of flammable gases, thereby significantly improving the flame retardant performance of the insulation board.

[0027] Optionally, the weight ratio of graphene oxide to inorganic flame retardant is 1:(1.5-3). When the weight ratio of graphene oxide to inorganic flame retardant is greater than 1:3, the content of graphene oxide is relatively low compared to inorganic flame retardant, resulting in a poor coating effect of graphene oxide on inorganic flame retardant. When the weight ratio of graphene oxide to inorganic flame retardant is less than 1:1.5, the content of graphene oxide is high, resulting in a better coating effect on inorganic flame retardant. However, a large amount of graphene oxide remains in the solution without coating the inorganic flame retardant, leading to low utilization. Simultaneously, the amount of inorganic flame retardant added is low, which to some extent reduces the mechanical properties of the insulation board material using the composite flame retardant of this application.

[0028] According to another aspect of this application, an insulation board prepared with a composite flame retardant as described in any of the preceding claims is provided.

[0029] Optionally, based on the total weight of the insulation board, the insulation board contains 58-78% by weight of a composite flame retardant for insulation boards.

[0030] The beneficial effects of this application include, but are not limited to:

[0031] 1. The composite flame retardant for insulation boards according to this application uses graphene oxide to coat the inorganic flame retardant, which can effectively disperse the inorganic flame retardant. Then, the graphene oxide coating the inorganic flame retardant is modified by fluorinated trichlorosilane and alkanolamine. By introducing perfluorinated groups, the flame retardant effect of the flame retardant can be enhanced, and the waterproof effect of the flame retardant can also be enhanced.

[0032] 2. The hydroxyl groups in the alkanolamine react with the chlorosilane groups in intermediate A to introduce the benzene ring groups and amine groups in the alkanolamine onto intermediate A, obtaining a modified graphene oxide-coated inorganic flame retardant. When this flame retardant is compounded with an N-absorbent flame retardant and added to the polymerization process of polyurethane insulation material, the amine groups can participate in the reaction in the polyurethane, thereby enabling the composite flame retardant to form chemical bonds with the polyurethane, preventing the flame retardant from settling and migrating outward, extending the effective life of the flame retardant, and further improving the service life of the insulation board.

[0033] 3. According to the composite flame retardant for insulation boards of this application, by compounding modified graphene oxide-coated inorganic flame retardant with N-series flame retardant, the flame retardant performance of the flame retardant can be strengthened. When applied to insulation boards, the fire resistance of the insulation boards can reach Class A non-combustible. At the same time, the addition of inorganic flame retardant can improve the mechanical properties of the material.

[0034] 4. The composite flame retardant in this application has both perfluorinated and amino groups, which can not only improve the bonding strength with the polyurethane-based insulation board and extend the service life of the flame retardant, but also improve the waterproof effect of the insulation board and enhance its overall performance. This allows the insulation board in this application to be better applied in practice, solving the problems of short waterproof performance and short service life of the flame retardant in existing insulation boards. Detailed Implementation

[0035] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0036] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0037] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art.

[0038] The graphene oxide used in the examples was prepared using the Hummers method.

[0039] Perfluorooctyltrichlorosilane CAS: 78560-45-9; Perfluorohexyltrichlorosilane CAS: 18560-47-1; Perfluorododecyltrichlorosilane CAS: 78560-44-8; Tetrachlorosilane CAS: 10026-04-7; N-Benzylethanolamine CAS: 104-63-2; N-Phenylenicethanolamine CAS: 122-98-5.

[0040] The solvent for the amine solution is a solvent that can dissolve N-benzylethanolamine, such as tetrahydrofuran, acetonitrile, toluene, etc.

[0041] Example 1

[0042] This embodiment relates to a composite flame retardant for insulation boards, which is prepared by: coating an inorganic flame retardant with modified graphene oxide at a weight ratio of 1:1.5 and mixing it with melamine by mechanical stirring.

[0043] The preparation of modified graphene oxide-coated inorganic flame retardants includes the following steps:

[0044] S1 Preparation of graphene oxide solution: Add 5.00g of graphene oxide to 995.00mL of aqueous solution and mix well to obtain a 0.5% graphene oxide solution;

[0045] S2 Preparation of graphene oxide-coated inorganic flame retardant: Add 0.5% graphene oxide solution to 150.00g magnesium hydroxide and treat at room temperature for 30min to obtain a solution containing graphene oxide-coated inorganic flame retardant;

[0046] Preparation of modified graphene oxide-coated inorganic flame retardant in step S3: Under nitrogen conditions, 1.50 g of perfluorooctyltrichlorosilane and 4.00 g of 20% sodium bicarbonate aqueous solution were added to the solution containing graphene oxide-coated inorganic flame retardant obtained in step S2. The mixture was modified at 50 °C for 1 h, filtered, and dried to obtain intermediate A. 1.58 g of N-benzylethanolamine was added to an appropriate amount of solvent to form an N-benzylethanolamine solution. Intermediate A was added to the N-benzylethanolamine solution, and the mixture was reacted at 20 °C for 12 h. After filtration and drying, the modified graphene oxide-coated inorganic flame retardant was obtained.

[0047] Example 2

[0048] The preparation method of the composite flame retardant for the insulation board in this embodiment is as follows:

[0049] Modified graphene oxide coated with inorganic flame retardant and N-series flame retardant in a weight ratio of 1:3 were mechanically stirred to obtain the composite flame retardant for the insulation board in this embodiment. The N-series flame retardant was a mixture of melamine and melamine cyanurate salt in a weight ratio of 1:1.5.

[0050] The preparation of the modified graphene oxide-coated inorganic flame retardant involved in this embodiment includes the following steps:

[0051] S1 Preparation of graphene oxide solution: 6.00 g of graphene oxide was added to 444.00 mL of aqueous solution and mixed evenly to obtain a 1.2% graphene oxide solution;

[0052] S2 Preparation of graphene oxide-coated inorganic flame retardant: 1.2% graphene oxide solution was added to 240.00g antimony trioxide and treated at room temperature for 30min to obtain a solution containing graphene oxide-coated inorganic flame retardant;

[0053] Preparation of modified graphene oxide-coated inorganic flame retardant in step S3: Under nitrogen conditions, 3.00 g of perfluorohexyltrichlorosilane and 4.00 g of 20% sodium bicarbonate aqueous solution were added to the solution containing graphene oxide-coated inorganic flame retardant obtained in step S2. The mixture was modified at 50 °C for 1 h, filtered, and dried to obtain intermediate A. 3.60 g of N-benzylethanolamine was added to an appropriate amount of solvent to form an N-benzylethanolamine solution. Intermediate A was added to the above solution, and the mixture was reacted at 40 °C for 15 h. After filtration and drying, the modified graphene oxide-coated inorganic flame retardant was obtained.

[0054] Example 3

[0055] The preparation method of the composite flame retardant for the insulation board in this embodiment is as follows:

[0056] Modified graphene oxide coated with inorganic flame retardant and N-series flame retardant in a weight ratio of 1:2 were mechanically stirred to obtain the composite flame retardant for the insulation board in this embodiment, wherein the N-series flame retardant was a mixture of melamine and dicyandiamide in a weight ratio of 1:1.

[0057] The preparation of the modified graphene oxide-coated inorganic flame retardant involved in this embodiment includes the following steps:

[0058] S1 Preparation of graphene oxide solution: Add 8.00g of graphene oxide to 992.00mL of aqueous solution and mix well to obtain a 0.8% graphene oxide solution;

[0059] S2 Preparation of graphene oxide-coated inorganic flame retardant: 0.8% graphene oxide solution was added to 280.00g aluminum hydroxide and treated at room temperature for 40min to obtain a solution containing graphene oxide-coated inorganic flame retardant;

[0060] S3 Preparation of modified graphene oxide-coated inorganic flame retardant: Under nitrogen conditions, 3.20 g of perfluorododecyltrichlorosilane and 4.00 g of 0.1 mol / L sodium hydroxide aqueous solution were added to the solution containing graphene oxide-coated inorganic flame retardant obtained in step S2. The mixture was modified at 65 °C for 2 h, filtered, and dried to obtain intermediate A. 3.50 g of N-phenylethanolamine was added to an appropriate amount of solvent to form an N-phenylethanolamine solution. Intermediate A was added to the above solution, and the mixture was reacted at 30 °C for 14 h. After filtration and drying, the modified graphene oxide-coated inorganic flame retardant was obtained.

[0061] Example 4

[0062] The difference between this embodiment and Embodiment 3 is that the amount of perfluorododecyltrichlorosilane added in step S3 is 6.40g, while the remaining steps are the same as in Embodiment 3.

[0063] Example 5

[0064] The difference between this embodiment and Example 3 is that the amount of perfluorododecyltrichlorosilane added in step S3 is 0.8g, while the other steps are the same as in Example 3.

[0065] Example 6

[0066] The difference between this embodiment and embodiment 3 is that the amount of N-phenylethanolamine added in step S3 is 1.20g, while the other steps are the same as in embodiment 3.

[0067] Example 7

[0068] The difference between this embodiment and embodiment 3 is that the amount of graphene oxide added in step S1 is 8.00 g, and the amount of aqueous solution added is 7992.00 mL. The remaining steps are the same as in embodiment 3.

[0069] Example 8

[0070] The difference between this embodiment and embodiment 3 is that the amount of aluminum hydroxide added in step S2 is 400.00g, while the other steps are the same as in embodiment 3.

[0071] Example 9

[0072] The difference between this embodiment and Embodiment 3 is that triethanolamine is used instead of N-phenylethanolamine in step S3, while the remaining steps are the same as in Embodiment 3.

[0073] Comparative Example 1

[0074] The difference between this comparative example and Example 3 is that the weight ratio of the modified graphene oxide-coated inorganic flame retardant and the N-series flame retardant is 1:5, while the remaining steps are the same as in Example 3.

[0075] Comparative Example 2

[0076] The difference between this comparative example and Example 3 is that the graphene oxide coating inorganic flame retardant was not modified. Instead, a 1:3 weight ratio of graphene oxide was used to coat magnesium hydroxide and melamine for compounding. The remaining steps were the same as in Example 3.

[0077] Comparative Example 3

[0078] The difference between this comparative example and Example 3 is that in step S3, tetrachlorosilane is used to modify the inorganic flame retardant coated on graphene oxide; the remaining steps are the same as in Example 3.

[0079] Comparative Example 4

[0080] The difference between this comparative example and Example 3 is that ethylene glycol is used instead of N-phenylethanolamine in step S3, while the remaining steps are the same as in Example 3.

[0081] Test Example 1

[0082] The flame retardant rating, waterproof effect, and mechanical properties of the above-mentioned compound flame retardant were tested. The test results are shown in Table 1, and the test methods are as follows:

[0083] 100 parts of polyol, 500 parts of composite flame retardant, 1 part of dibutyltin dilaurate, 20 parts of hydroxyl silicone oil, and 1 part of water were mixed at high speed for 3 minutes to obtain a mixture. Then, 120 parts of hexamethylene diisocyanate were added to the mixture, stirred, and poured into a mold. The mixture was heated to 65°C for foaming and cured for 30 minutes. The mold was then opened to obtain the material. The above-mentioned composite flame retardants are the composite flame retardants prepared in Examples 1-9 and Comparative Examples 1-4, respectively.

[0084] Compressive strength: The compressive strength (MPa) is tested according to GB / T21558-2008. The higher the compressive strength, the better the strength of the insulation board.

[0085] Water absorption rate: Cut the prepared polyurethane material into 10cm×10cm samples, clean the surface and place them in a drying oven at 60℃±1℃ to constant weight. After cooling to room temperature, record the weight as W1. Place the sample in a container and add distilled water to cover the sample surface. After soaking for 24 hours, gently absorb the excess water from the sample surface with a clean cloth, weigh and record the wet weight as W2. Calculate the water absorption rate using the formula: Water absorption rate (%) = (W2-W1) / W1×100%.

[0086] Thermal conductivity: The thermal conductivity (W / mk) is tested according to GB / T10294. The higher the thermal conductivity, the worse the thermal insulation performance of the insulation board.

[0087] Limiting oxygen index: The combustion performance is tested according to GB8624-2012, and the limiting oxygen index (%) is tested. The installation of the combustion sample is in accordance with GB / T20284-2006. The higher the limiting oxygen index, the better the flame retardant performance of the insulation board.

[0088] Table 1

[0089]

[0090] Test Example 2

[0091] The products prepared in Test Example 1 were stored in a room temperature storage room for 6 months, and then the limiting oxygen index of the products was tested again. The test data are shown in Table 2.

[0092] Table 2

[0093]

[0094]

[0095] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A composite flame retardant for insulation boards, characterized in that, Including modified graphene oxide-coated inorganic flame retardants and N-series flame retardants in a weight ratio of 1:(1.5-3); The preparation method of the modified graphene oxide-coated inorganic flame retardant is as follows: S1 Preparation of graphene oxide solution: Add graphene oxide to an aqueous solution and mix thoroughly to obtain a graphene oxide solution; S2 Preparation of graphene oxide-coated inorganic flame retardant: Add graphene oxide solution to inorganic flame retardant to obtain a solution containing graphene oxide-coated inorganic flame retardant; S3 Preparation of modified graphene oxide-coated inorganic flame retardant: Under inert gas conditions, add fluorinated trichlorosilane and an acid-binding agent to the solution containing graphene oxide-coated inorganic flame retardant obtained in step S2, modify at 50-80℃ for 1-3 hours, filter and dry to obtain intermediate A; then add intermediate A to an alkanolamine solution, react at 20-40℃ for 12-15 hours, filter and dry to obtain modified graphene oxide-coated inorganic flame retardant.

2. The composite flame retardant for insulation boards according to claim 1, characterized in that, The structural formula of the fluorinated trichlorosilane in S3 is shown in formula (1). R1 is selected from one of perfluorooctyl, perfluorohexyl, and perfluorododecyl.

3. The composite flame retardant for insulation boards according to claim 1, characterized in that, The weight ratio of the graphene oxide to the fluorinated trichlorosilane is 1:(0.3-0.5); The weight ratio of the fluorinated trichlorosilane to the alkanolamine is 1:(1.05-1.2).

4. The composite flame retardant for insulation boards according to claim 1, characterized in that, The alcohol amine in S3 is one or more of N-benzylethanolamine and N-phenylethanolamine.

5. The composite flame retardant for insulation boards according to claim 1, characterized in that, The concentration of the graphene oxide solution in S1 is 0.5-1.2%.

6. The composite flame retardant for insulation boards according to claim 1, characterized in that, The inorganic flame retardant in S2 is one or more of aluminum hydroxide, magnesium hydroxide, and antimony trioxide.

7. The composite flame retardant for insulation boards according to claim 1, characterized in that, The N-series flame retardant is one or more of melamine, dicyandiamide, and melamine cyanurate.

8. The composite flame retardant for insulation boards according to claim 1, characterized in that, The weight ratio of graphene oxide to inorganic flame retardant is 1:(30-40).

9. The insulation board prepared by the composite flame retardant according to any one of claims 1-8.

10. The thermal insulation material according to claim 9, characterized in that, Based on the total weight of the insulation board, the insulation board contains 58-78% by weight of a composite flame retardant for insulation boards.

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