High-efficiency phosphorus-based hybrid flame-retardant smoke-suppressing agent, preparation method and application thereof

Abstract

The application discloses a kind of efficient phosphorus hybrid flame-retardant smoke suppressant and its preparation method and application, belong to flame-retardant material technical field.The application first prepares the hollow zinc-based metal organic framework material that can be regulated by solution method and tannic acid etching method, then obtains the TA-ZIF-8 with amino functional group by ligand replacement reaction, grafts phosphorus-containing organic small molecule, to obtain the efficient phosphorus hybrid flame-retardant smoke suppressant P- TA-ZIF-8 containing phosphorus, hollow structure and metal zinc simultaneously.The flame-retardant epoxy resin composite material prepared by using the P- TA-ZIF-8 prepared in the application and epoxy resin as flame retardant and matrix material respectively has good flame-retardant performance and smoke suppression performance, and the oxygen index is 31.0~34.2%, which belongs to difficult flammable material.

Description

A high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant, its preparation method and application Technical Field

[0001] This invention belongs to the field of flame retardant materials technology, and particularly relates to a high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant, its preparation method, and its application. Background Technology

[0002] Polymer materials are widely used in construction, transportation, electronics, and aerospace. However, most polymer materials are flammable, posing a serious fire hazard. Therefore, flame-retardant modification of polymer materials is crucial. An ideal flame retardant should be highly efficient, low in toxicity, have good compatibility with the matrix, be environmentally friendly, and not significantly affect the mechanical properties of the material. Developing novel, highly efficient flame retardants has always been a research hotspot and challenge in this field.

[0003] Currently, commonly used flame retardants mainly include halogenated, phosphorus-based, nitrogen-based, and inorganic hydroxides. While halogenated flame retardants have high flame retardant efficiency, they release toxic and corrosive gases during combustion. Traditional phosphorus-based flame retardants have improved environmental friendliness, but often suffer from problems such as high dosage requirements, easy migration, high volatility, and poor durability, and may also deteriorate the thermodynamic properties of the base material. Inorganic hydroxides (such as aluminum hydroxide and magnesium hydroxide) are environmentally friendly, but require very high dosages to achieve excellent flame retardant effects, which can severely impair the processability and mechanical properties of the material. Nitrogen-based flame retardants (such as melamine-based ones) often need to be used in combination with other flame retardants, as their efficiency is limited when used alone.

[0004] To address these issues, nanotechnology for flame retardancy has emerged. Among these, metal-organic frameworks (MOFs), as a novel type of porous crystalline material, have shown great potential in the field of flame retardancy due to their high specific surface area, tunable pore structure, and chemical composition. MOFs can act as acid, gas, or carbon sources, exerting flame-retardant effects in both condensed and gas phases. Their nanoscale effects also help improve compatibility with polymer matrices. Although MOFs hold great promise as flame retardants, their direct application still faces significant bottlenecks: First, most current research involves physically blending MOFs into polymers as fillers. This approach suffers from problems such as easy MOF aggregation, weak interfacial interaction with polymers, and easy migration of flame-retardant components, resulting in failure to maximize flame-retardant efficiency and potentially negatively impacting the mechanical properties of the material. Second, the surface chemistry of MOFs may be incompatible with the polymer matrix to be modified, leading to poor dispersibility. Moreover, many MOFs themselves have limited flame-retardant efficiency, failing to meet high-standard flame-retardant requirements. For hollow MOFs, the potential for flame-retardant functionalization of their cavities has not been fully explored. How to accurately introduce highly efficient flame-retardant groups or elements into their inner and outer surfaces and cavities is a technical challenge.

[0005] Phosphorus-based flame retardants are highly effective in promoting char formation in condensed phases. Grafting phosphorus-containing organic compounds onto hollow MOFs via strong chemical bonds is considered a highly attractive solution. The metal component of the MOF can act as a Lewis acid, catalyzing polymer dehydration and crosslinking, and together with the phosphorus-containing component, constructing a robust and dense expanded char layer, achieving highly efficient synergistic flame retardancy between phosphorus and metal. Chemical grafting prevents flame retardant migration and exudation, imparting durable flame retardancy to the material. The grafted organic chains can improve the compatibility between MOFs and the polymer matrix, enhancing the overall performance of the composite material. However, there is currently no mature and reliable solution for achieving efficient, uniform, and stable chemical grafting of phosphorus-containing organic compounds onto hollow MOFs while perfectly maintaining the integrity of their hollow structure. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a highly efficient phosphorus-based hybrid flame retardant and smoke suppressant, its preparation method, and its application.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for preparing a highly efficient phosphorus-based hybrid flame retardant and smoke suppressant, comprising the following steps:

[0009] (1) The zinc source solution and 2-methylimidazole solution were mixed, and then a deprotonating agent was added. After coordination reaction, zinc-based metal-organic framework material (ZIF-8) was obtained.

[0010] (2) The zinc-based metal-organic framework material and tannic acid (TA) are dissolved in water and etched to obtain hollow zinc-based metal-organic framework material (TA-ZIF-8).

[0011] (3) Dissolve the hollow zinc-based metal-organic framework material and 3,5-diamino-1,2,4-triazole in an organic solvent to carry out a substitution reaction to obtain an amino-containing hollow zinc-based metal-organic framework material (NH2-TA-ZIF-8).

[0012] (4) The amino-containing hollow zinc-based metal-organic framework material is dispersed in an organic solvent to obtain a dispersion; under protective gas and ice-water bath conditions, a phosphorus-containing organic small molecule solution is added to the dispersion, and then a heating reflux reaction is carried out to obtain the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant (P-TA-ZIF-8).

[0013] Further, in step (1), the mass ratio of zinc source in the zinc source solution to 2-methylimidazole in the 2-methylimidazole solution is (5~7):(12~14); the deprotonating reagent is selected from NaOH; the molar ratio of NaOH to zinc source in the zinc source solution is (8~22):1.

[0014] Furthermore, in step (1), the temperature of the coordination reaction is room temperature, and the time of the coordination reaction is 6~10h.

[0015] Further, in step (2), the mass ratio of the zinc-based metal-organic framework material to tannic acid is 1:(0.4~0.6).

[0016] Furthermore, in step (2), the etching reaction is carried out at room temperature and for 20-40 minutes.

[0017] Further, in step (3), the mass ratio of the hollow zinc-based metal-organic framework material to 3,5-diamino-1,2,4-triazole is 1:(0.9~1.1).

[0018] The displacement reaction is carried out at room temperature for 10-14 hours.

[0019] Further, in step (4), the mass ratio of the amino-containing hollow zinc-based metal-organic framework material to the phosphorus-containing organic small molecule solution is (4~6):(8~12); the phosphorus-containing organic small molecule is selected from diphenylphosphoyl chloride or phenylphosphonodichloride.

[0020] Furthermore, in step (4), the temperature of the heating reflux reaction is 60°C, and the heating reflux reaction time is 2h.

[0021] This invention provides a highly efficient phosphorus-based hybrid flame retardant and smoke suppressant, which is prepared according to the preparation method described in the above technical solution.

[0022] The present invention also provides the application of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant as described above in the preparation of flame retardant epoxy resin composite materials.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] This invention first prepares a tunable hollow zinc-based metal-organic framework material (TA-ZIF-8) via solution method and tannic acid etching method. Then, TA-ZIF-8 with amino functional groups (NH2-TA-ZIF-8) is obtained through ligand substitution reaction. Phosphorus-containing organic small molecules are then grafted onto this ligand, resulting in a highly efficient phosphorus-based hybrid flame retardant and smoke suppressant, P-TA-ZIF-8, which simultaneously contains phosphorus, has a hollow structure, and contains metallic zinc. Flame-retardant epoxy resin composites prepared using P-TA-ZIF-8 prepared in this invention and epoxy resin as the flame retardant and matrix material, respectively, exhibit excellent flame retardant and smoke suppression properties.

[0025] In the preparation of ZIF-8, this invention uses a deprotonating agent to regulate the crystal form and size of ZIF-8, and then uses tannic acid to etch ZIF-8. Tannic acid (TA) releases free protons, which can destroy the framework of ZIF-8. Moreover, the relatively large molecular size of tannic acid can block the pores of ZIF-8, thereby protecting ZIF-8 from complete collapse, and finally obtaining a zinc-based metal-organic framework material with a hollow structure.

[0026] The high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant prepared in this invention contains phosphorus, a hollow structure, and metallic zinc. The synergistic effect of these three components improves the flame retardant and smoke suppressant properties of epoxy resin composites. The grafted organophosphorus molecules improve the compatibility of ZIF-8 with the epoxy resin matrix and enhance the mechanical properties of the composite material. Simultaneously, phosphorus decomposes during combustion to generate phosphorus-containing free radicals such as PO·, HPO·, and HPO2·, which interrupt or slow down the chain reaction of combustion by consuming the highly active H· and ·OH that maintain the flame, thereby improving flame retardancy and smoke suppression. The hollow structure can adsorb and collect combustible gases generated during combustion, thus inhibiting combustion. Metallic zinc acts as a Lewis acid, catalyzing polymer dehydration and crosslinking, and together with the phosphorus-containing components, constructs a robust and dense expanded char layer, achieving highly efficient synergistic flame retardancy between phosphorus and metal. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 is a process flow diagram of the preparation method of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant provided by the present invention;

[0029] Figure 2 shows the SEM and TEM images of the highly efficient phosphorus-based hybrid flame retardant and smoke suppressant P-TA-ZIF-8 prepared in Example 1, where (a) is the SEM image and (b) is the TEM image.

[0030] Figure 3 shows the SEM and TEM images of the phosphorus-based flame retardant and smoke suppressant prepared in Comparative Example 1, where (a) is the SEM image and (b) is the TEM image.

[0031] Figure 4 shows the SEM and TEM images of the highly efficient phosphorus-based hybrid flame retardant and smoke suppressant P-TA-ZIF-8 prepared in Example 2, where (a) is the SEM image and (b) is the TEM image.

[0032] Figure 5 shows the SEM and TEM images of ZIF-8 prepared in step (1) of Example 1, where (a) is the SEM image and (b) is the TEM image.

[0033] Figure 6 shows the infrared spectra of ZIF-8 prepared in step (1), TA-ZIF-8 prepared in step (2), NH2-TA-ZIF-8 prepared in step (3) and P-TA-ZIF-8 prepared in step (4) of Example 1.

[0034] Figure 7 shows the heat release peak values ​​of the flame-retardant epoxy resin composites prepared in Examples 3, 7 and Comparative Examples 2-6;

[0035] Figure 8 shows the total heat release of the flame-retardant epoxy resin composites prepared in Examples 3, 7, and Comparative Examples 2-6.

[0036] Figure 9 shows the peak smoke emission of the materials prepared in Examples 3, 7 and Comparative Examples 2-6;

[0037] Figure 10 shows the total smoke release of the materials prepared in Examples 3, 7 and Comparative Examples 2-6. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] This invention provides a method for preparing a high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant, comprising the following steps:

[0041] (1) The zinc source solution and the 2-methylimidazole solution were mixed, and then a deprotonating reagent was added. After coordination reaction, zinc-based metal-organic framework materials were obtained.

[0042] (2) The zinc-based metal-organic framework material and tannic acid are dissolved in water and etched to obtain a hollow zinc-based metal-organic framework material;

[0043] (3) Dissolve the hollow zinc-based metal-organic framework material and 3,5-diamino-1,2,4-triazole in an organic solvent to carry out a displacement reaction to obtain an amino-containing hollow zinc-based metal-organic framework material.

[0044] (4) The amino-containing hollow zinc-based metal-organic framework material is dispersed in an organic solvent to obtain a dispersion; a phosphorus-containing organic small molecule solution is added to the dispersion under protective gas and ice-water bath conditions, and then heated and refluxed to obtain the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant.

[0045] In a preferred embodiment, in step (1), the mass ratio of zinc source in the zinc source solution to 2-methylimidazole in the 2-methylimidazole solution is (5~7):(12~14), more preferably 5.8:13; the zinc source is selected from zinc nitrate hexahydrate; the solvents of both the zinc source solution and the 2-methylimidazole solution are deionized water. This invention uses zinc-based metal-organic framework materials as a matrix, where metallic zinc acts as a Lewis acid to catalyze polymer dehydration and crosslinking, jointly constructing a robust and dense expanded carbon layer with phosphorus-containing components, achieving efficient synergistic flame retardancy between phosphorus and metal.

[0046] In a preferred embodiment, in step (1), the deprotonating agent is selected from NaOH; the molar ratio of NaOH to the zinc source in the zinc source solution is (8~22):1, more preferably (10.25~20.5):1. This invention uses NaOH as a deprotonating agent to regulate and promote the growth of ZIF-8 crystals. By controlling the amount of NaOH added, the crystal form and size of ZIF-8 can be controlled, thereby improving the flame retardant properties of epoxy resin.

[0047] In a preferred embodiment, in step (1), the temperature of the coordination reaction is room temperature, and the time of the coordination reaction is 6~10h.

[0048] In a preferred embodiment, step (1) further includes washing and drying steps after the coordination reaction; the washing reagent is ethanol; and the drying temperature is 60~80℃.

[0049] In a preferred embodiment, in step (2), the mass ratio of the zinc-based metal-organic framework material to tannic acid is 1:(0.4~0.6), more preferably 1:0.5. Tannic acid (TA) releases free protons, which can destroy the framework of ZIF-8. Moreover, the relatively large molecular size of tannic acid can block the pores of ZIF-8, thereby protecting ZIF-8 from complete collapse and ultimately obtaining a hollow structure. The hollow structure can adsorb and collect combustible gases generated during combustion, thereby inhibiting combustion.

[0050] In a preferred embodiment, in step (2), the etching reaction is carried out at room temperature for 20 to 40 minutes.

[0051] In a preferred embodiment, step (2) further includes a washing and drying step after the etching reaction; the washing reagent is ethanol; and the drying temperature is 60~80℃.

[0052] In a preferred embodiment, in step (3), the mass ratio of the hollow zinc-based metal-organic framework material to 3,5-diamino-1,2,4-triazole is 1:(0.9~1.1), and more preferably 1:1.

[0053] In a preferred embodiment, in step (3), the organic solvent is anhydrous ethanol.

[0054] In a preferred embodiment, in step (3), the temperature of the displacement reaction is room temperature, and the time of the displacement reaction is 10~14h.

[0055] In a preferred embodiment, step (3) further includes washing and drying steps after the displacement reaction; the washing reagent is ethanol; and the drying temperature is 60~80℃.

[0056] In a preferred embodiment, in step (4), the mass ratio of the amino-containing hollow zinc-based metal-organic framework material to the phosphorus-containing organic small molecule solution is (4~6):(8~12), more preferably 5:10; the phosphorus-containing organic small molecule is selected from diphenylphosphoyl chloride or phenylphosphonodichloride. The grafted organophosphorus small molecules of the present invention can improve the compatibility of ZIF-8 with the epoxy resin matrix, enhance the mechanical properties of the composite material, and at the same time, when phosphorus burns, it decomposes to generate phosphorus-containing free radicals such as PO·, HPO·, and HPO2·, which interrupt or slow down the chain reaction of combustion by consuming the highly active H· and ·OH that maintain the flame, thereby improving flame retardancy and smoke suppression.

[0057] In a preferred embodiment, in step (4), the organic solvent is acetone; the solvent of the phosphorus-containing organic small molecule solution is acetone.

[0058] In a preferred embodiment, in step (4), the temperature of the heating reflux reaction is 60°C and the time of the heating reflux reaction is 2 hours.

[0059] In a preferred embodiment, step (4) further includes washing and drying steps after the heating and reflux reaction; the washing reagent is ethanol; and the drying temperature is 60~80℃.

[0060] This invention provides a highly efficient phosphorus-based hybrid flame retardant and smoke suppressant, which is prepared according to the preparation method described in the above technical solution.

[0061] The present invention also provides the application of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant as described above in the preparation of flame retardant epoxy resin composite materials.

[0062] In a preferred embodiment, the application of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant in the preparation of flame-retardant epoxy resin composite materials includes the following steps:

[0063] S1. The high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant and epoxy resin are placed in an organic solvent, and after heating, stirring and degassing, mixture A is obtained;

[0064] S2. Add curing agent to the mixture A. After the curing agent is completely dissolved, cure it sequentially at 80~100℃ for 2~3h, 120~140℃ for 1~2h, and 160~180℃ for 1~2h to obtain the flame-retardant epoxy resin composite material.

[0065] In a preferred embodiment, in step S1, the mass ratio of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant to the epoxy resin in the mixture A is (1~4):80.

[0066] In a preferred embodiment, in step S1, the organic solvent is any one of dichloromethane, chloroform, and acetone; based on the amount of epoxy resin used being 80g, the amount of the organic solvent used is 50mL.

[0067] In a preferred embodiment, in step S1, the temperature of the heating and stirring is 80°C.

[0068] In a preferred embodiment, in step S2, the curing agent is 4,4-diaminodiphenylmethane or diethylenetriamine; the mass ratio of the curing agent to the epoxy resin is 20:80.

[0069] In this embodiment of the invention, room temperature refers to 25±2℃.

[0070] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels.

[0071] Example 1

[0072] A method for preparing a high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant, the process flow diagram of which is shown in Figure 1, and the specific steps are as follows:

[0073] (1) Dissolve 0.58 g of zinc nitrate hexahydrate in 25 mL of deionized water to obtain zinc nitrate hexahydrate solution; dissolve 1.3 g of 2-methylimidazole in 25 mL of deionized water to obtain 2-methylimidazole solution; under magnetic stirring, slowly pour the zinc nitrate hexahydrate solution into the 2-methylimidazole solution and mix evenly, then add 1.6 g of NaOH for conditioning (the molar ratio of NaOH to zinc nitrate hexahydrate is 20.5:1), stir the reaction at room temperature for 8 h, wash the reactants with ethanol, and dry them at 60 °C to obtain zinc-based metal-organic framework material ZIF-8;

[0074] (2) Place 0.5g of tannic acid TA in 100mL of deionized water and stir thoroughly with a magnetic stirrer to dissolve it, thus obtaining a tannic acid solution; slowly add 1g of ZIF-8 obtained in step (1) to the above tannic acid solution, and stir thoroughly with a magnetic stirrer for 30min at room temperature to carry out the etching reaction. Wash the reactants with ethanol and dry them at 60℃ to obtain hollow zinc-based metal-organic framework material TA-ZIF-8.

[0075] (3) Dissolve 0.5g of TA-ZIF-8 obtained in step (2) and 0.5g of 3,5-diamino-1,2,4-triazole in 100mL of anhydrous ethanol, stir at room temperature for 12h, wash the product with ethanol, and dry at 60℃ to obtain NH2-TA-ZIF-8, an amino-containing hollow zinc-based metal-organic framework material.

[0076] (4) Disperse 0.5g of NH2-TA-ZIF-8 obtained in step (3) in 50mL of acetone and sonicate to obtain NH2-TA-ZIF-8 solution; disperse 1g of diphenylphosphine chloride in 25mL of acetone to obtain diphenylphosphine chloride solution; under nitrogen and ice-water bath conditions, slowly add diphenylphosphine chloride solution to NH2-TA-ZIF-8 solution using a constant pressure dropping funnel, stir for 1h, then heat to 60℃ and reflux for 2h, wash the reaction product with ethanol, and dry at 60℃ to obtain high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant P-TA-ZIF-8.

[0077] Example 2

[0078] The preparation method of a high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant differs from Example 1 only in that, in step (1), 0.8g of NaOH is added for conditioning (the molar ratio of NaOH to zinc nitrate hexahydrate is 10.25:1), and the rest is the same as in Example 1.

[0079] Comparative Example 1

[0080] A method for preparing a phosphorus-based flame retardant and smoke suppressant differs from Example 1 only in that NaOH is not added in step (1), while the rest is the same as in Example 1.

[0081] Figure 2 shows the SEM and TEM images of the highly efficient phosphorus-based hybrid flame retardant and smoke suppressant P-TA-ZIF-8 prepared in Example 1, where (a) is the SEM image and (b) is the TEM image.

[0082] Figure 3 shows the SEM and TEM images of the phosphorus-based flame retardant and smoke suppressant prepared in Comparative Example 1, where (a) is the SEM image and (b) is the TEM image.

[0083] Figure 4 shows the SEM and TEM images of the highly efficient phosphorus-based hybrid flame retardant and smoke suppressant P-TA-ZIF-8 prepared in Example 2, where (a) is the SEM image and (b) is the TEM image.

[0084] Figure 5 shows the SEM and TEM images of ZIF-8 prepared in step (1) of Example 1, where (a) is the SEM image and (b) is the TEM image.

[0085] As shown in Figures 2-5, the preparation of the zinc-based metal-organic framework material in this invention is carried out under the control of NaOH, which allows for increased crystal size and more regular crystal form, ultimately resulting in P-TA-ZIF-8 with a hollow structure. Simultaneously, tannic acid (TA) can achieve hollow etching while maintaining the ZIF-8 structure from collapsing, and the crystal form and size of ZIF-8 can be controlled by adjusting the amount of NaOH added. Without the addition of NaOH, the ZIF-8 particles are small, have poor crystal form, and are prone to agglomeration, which is detrimental to improving the flame-retardant properties of the epoxy resin.

[0086] Figure 6 shows the infrared spectra of ZIF-8 prepared in step (1), TA-ZIF-8 prepared in step (2), NH2-TA-ZIF-8 prepared in step (3), and P-TA-ZIF-8 prepared in step (4) of Example 1. As can be seen from Figure 6, the infrared spectra of ZIF-8, TA-ZIF-8, NH2-TA-ZIF-8, and P-TA-ZIF-8 are in the range of 1000-1300 cm⁻¹. -1 The presence of absorption peaks attributable to the imidazole ring within the range indicates that the dimethylimidazolium ligand was partially, rather than completely, replaced. The infrared spectra of NH2-TA-ZIF-8 and P-TA-ZIF-8 show peaks at 3456 cm⁻¹, respectively. -1 3342cm -1 1551cm -1 and 1507cm -1 A new peak belonging to NH2 and the triazole ring appeared, indicating that dimethylimidazole was successfully aminated by the substitution of 3,5-diamino-1,2,4-triazole. Furthermore, a new peak (804 cm⁻¹) appeared on the infrared spectrum of P-TA-ZIF-8. -1 The peaks (attributed to the PN vibration) indicate that diphenylphosphoyl chloride (DPPC) was successfully grafted onto ZIF-8. All these results demonstrate that this invention successfully prepared the phosphorus-containing hollow zinc-based metal-organic framework material P-TA-ZIF-8.

[0087] Example 3

[0088] A method for preparing a flame-retardant epoxy resin composite material, comprising the following steps:

[0089] Take 2g of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant P-TA-ZIF-8 prepared in Example 1, 80g of thermosetting E51 bisphenol A type epoxy resin and 50mL of acetone, stir at 80°C until transparent, and degas until no bubbles are generated to obtain mixture A; then add 20g of 4,4-diaminodiphenylmethane to mixture A, and after it is completely dissolved, pour it into a preheated mold, and cure it sequentially at 80°C for 3h, 120°C for 2h, and 160°C for 1h to obtain a flame retardant epoxy resin composite material, denoted as P-TA-ZIF-8 / EP.

[0090] Example 4

[0091] A method for preparing a flame-retardant epoxy resin composite material differs from Example 3 only in that 1g of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant P-TA-ZIF-8 prepared in Example 1, 80g of thermosetting E51 bisphenol A type epoxy resin, and 50mL of acetone are stirred at 80°C until transparent, while the rest is the same as in Example 1.

[0092] Example 5

[0093] A method for preparing a flame-retardant epoxy resin composite material differs from Example 3 only in that 3g of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant P-TA-ZIF-8 prepared in Example 1, 80g of thermosetting E51 bisphenol A type epoxy resin, and 50mL of acetone are stirred at 80°C until transparent, while the rest is the same as in Example 1.

[0094] Example 6

[0095] A method for preparing a flame-retardant epoxy resin composite material differs from Example 3 only in that 4g of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant P-TA-ZIF-8 prepared in Example 1, 80g of thermosetting E51 bisphenol A type epoxy resin, and 50mL of acetone are stirred at 80°C until transparent, while the rest is the same as in Example 1.

[0096] Example 7

[0097] A method for preparing a flame-retardant epoxy resin composite material differs from Example 3 only in that 2g of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant P-TA-ZIF-8 prepared in Example 2, 80g of thermosetting E51 bisphenol A type epoxy resin, and 50mL of acetone are stirred at 80°C until transparent, while the rest is the same as in Example 1; the resulting flame-retardant epoxy resin composite material is denoted as P-TA-ZIF-8-2 / EP.

[0098] Comparative Example 2

[0099] A method for preparing a flame-retardant epoxy resin composite material differs from Example 3 only in that 2g of the phosphorus-based flame retardant and smoke suppressant prepared in Comparative Example 1, 80g of thermosetting E51 bisphenol A type epoxy resin, and 50mL of acetone are stirred at 80°C until transparent, while the rest is the same as in Example 1; the resulting flame-retardant epoxy resin composite material is denoted as P-TA-ZIF-8-1 / EP.

[0100] Comparative Example 3

[0101] A method for preparing a flame-retardant epoxy resin composite material differs from Example 3 only in that the highly efficient phosphorus-based hybrid flame retardant and smoke suppressant P-TA-ZIF-8 prepared in Example 1 is not added. That is, the material obtained in this comparative example is a pure epoxy resin material, denoted as EP.

[0102] Comparative Example 4

[0103] A method for preparing a flame-retardant epoxy resin composite material differs from Example 3 only in that 2g of ZIF-8 prepared in step (1) of Example 1, 80g of thermosetting E51 bisphenol A type epoxy resin and 50mL of acetone are taken and stirred at 80°C until transparent, and the rest is the same as in Example 1; the obtained flame-retardant epoxy resin composite material is denoted as ZIF-8 / EP.

[0104] Comparative Example 5

[0105] A method for preparing a flame-retardant epoxy resin composite material differs from Example 3 only in that 2g of TA-ZIF-8 prepared in step (2) of Example 1, 80g of thermosetting E51 bisphenol A type epoxy resin and 50mL of acetone are taken and stirred at 80°C until transparent, and the rest is the same as in Example 1; the obtained flame-retardant epoxy resin composite material is denoted as TA-ZIF-8 / EP.

[0106] Comparative Example 6

[0107] A method for preparing a flame-retardant epoxy resin composite material differs from Example 3 only in that 2g of NH2-TA-ZIF-8 prepared in step (3) of Example 1, 80g of thermosetting E51 bisphenol A type epoxy resin and 50mL of acetone are taken and stirred at 80°C until transparent, and the rest is the same as in Example 1; the obtained flame-retardant epoxy resin composite material is denoted as NH2-TA-ZIF-8 / EP.

[0108] According to the international standard ASTM-ISO 5660, cone calorimeter was used to conduct cone calorimeter tests on the flame-retardant epoxy resin composite materials of Example 3 and Comparative Examples 3-6. The test results are shown in Figures 7-10.

[0109] Figure 7 shows the peak heat release values ​​of the flame-retardant epoxy resin composites prepared in Examples 3, 7, and Comparative Examples 2-6. Figure 8 shows the total heat release values ​​of the flame-retardant epoxy resin composites prepared in Examples 3, 7, and Comparative Examples 2-6. As can be seen from Figures 7 and 8, compared to pure epoxy resin (Comparative Example 3, EP), the peak heat release value of the flame-retardant epoxy resin composite prepared in Example 3 was reduced by 66%, and the total heat release value was reduced by 51%, indicating a significant improvement in flame retardancy. Furthermore, comparing the results of Examples 3, 7, and Comparative Example 2 shows that NaOH can promote the crystal growth of ZIF-8, forming ZIF-8 with better crystal structure, larger size, and greater uniformity. The resulting P-TA-ZIF-8 is more beneficial in reducing the heat release value of the epoxy resin composite.

[0110] Figure 9 shows the peak smoke emission values ​​of the materials prepared in Examples 3, 7, and Comparative Examples 2-6. Figure 10 shows the total smoke emission values ​​of the materials prepared in Examples 3, 7, and Comparative Examples 2-6. As can be seen from Figures 9 and 10, compared to pure epoxy resin (Comparative Example 3, EP), the peak smoke emission value of the flame-retardant epoxy resin composite material prepared in Example 3 was reduced by 53%, and the total smoke emission value was reduced by 49%, indicating a significant improvement in smoke suppression. Furthermore, consistent with the heat release results, a comparison of the results from Examples 3, 7, and Comparative Example 2 shows that the P-TA-ZIF-8 obtained after adding NaOH is more beneficial in reducing the smoke emission value of the epoxy resin composite material.

[0111] According to the international standard ASTM-D 2863, the oxygen index of the flame-retardant epoxy resin composites prepared in Examples 3-7 and Comparative Examples 2-6 was tested using an oxygen indexer, and the test results are shown in Table 1. According to the international standard ASTM-D 3801, the vertical flammability rating of the flame-retardant epoxy resin composites prepared in Examples 3-7 and Comparative Examples 2-6 was tested using a vertical flammability tester, and the test results are shown in Table 1.

[0112] Table 1. Oxygen Index and Vertical Combustion Rating Test Results

[0113]

[0114] Note: NR indicates that it does not have a basic flame retardant rating.

[0115] As shown in Table 1, the oxygen index of the flame-retardant epoxy resin composite material prepared using the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant prepared in this invention as a flame retardant is 31.0~34.2%. According to the international standard ASTM-D 2863, the flame-retardant epoxy resin composite material prepared in this invention belongs to the category of flame-retardant materials.

[0116] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant, characterized in that, Includes the following steps: (1) A zinc source solution and a 2-methylimidazole solution are mixed, and then a deprotonating reagent is added. After coordination reaction, a zinc-based metal-organic framework material is obtained. The deprotonating reagent is selected from NaOH. The molar ratio of NaOH to zinc source in the zinc source solution is (8~22):

1. (2) The zinc-based metal-organic framework material and tannic acid are dissolved in water and etched to obtain a hollow zinc-based metal-organic framework material. (3) The hollow zinc-based metal-organic framework material and 3,5-diamino-1,2-dimethylimidazole solution are mixed. ,4-triazole is dissolved in an organic solvent to undergo a displacement reaction to obtain an amino-containing hollow zinc-based metal-organic framework material; (4) the amino-containing hollow zinc-based metal-organic framework material is dispersed in an organic solvent to obtain a dispersion; under protective gas and ice-water bath conditions, a phosphorus-containing organic small molecule solution is added to the dispersion, and then a heating reflux reaction is carried out to obtain the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant; the phosphorus-containing organic small molecule in the phosphorus-containing organic small molecule solution is selected from diphenylphosphonic chloride or phenylphosphonic dichloride.

2. The preparation method of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant according to claim 1, characterized in that, In step (1), the mass ratio of zinc source in the zinc source solution to 2-methylimidazole in the 2-methylimidazole solution is (5~7):(12~14).

3. The preparation method of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant according to claim 1, characterized in that, In step (1), the coordination reaction is carried out at room temperature for 6 to 10 hours.

4. The preparation method of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant according to claim 1, characterized in that, In step (2), the mass ratio of the zinc-based metal-organic framework material to tannic acid is 1:(0.4~0.6).

5. The preparation method of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant according to claim 1, characterized in that, In step (2), the etching reaction is carried out at room temperature for 20 to 40 minutes.

6. The preparation method of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant according to claim 1, characterized in that, In step (3), the mass ratio of the hollow zinc-based metal-organic framework material to 3,5-diamino-1,2,4-triazole is 1:(0.9~1.1); the temperature of the displacement reaction is room temperature, and the time of the displacement reaction is 10~14h.

7. The preparation method of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant according to claim 1, characterized in that, In step (4), the mass ratio of the amino-containing hollow zinc-based metal-organic framework material to the phosphorus-containing organic small molecule solution is (4~6):(8~12).

8. The preparation method of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant according to claim 1, characterized in that, In step (4), the temperature of the heating reflux reaction is 60°C and the time of the heating reflux reaction is 2 hours.

9. A highly efficient phosphorus-based hybrid flame retardant and smoke suppressant, characterized in that, It is prepared according to any one of claims 1 to 8.

10. The application of the high-efficiency phosphorus-based hybrid flame retardant and smoke suppressant as described in claim 9 in the preparation of flame-retardant epoxy resin composite materials.

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