N-P hybrid modified illite flame retardant as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of flame retardants, and provides an N-P hybrid modified illite flame retardant and a preparation method and application thereof.The N-P hybrid modified illite flame retardant takes illite, lauryl amine, melamine and a phosphorus-containing acid solution as reaction raw materials, and the preparation method of the N-P hybrid modified illite flame retardant comprises the steps that a, the illite is dispersed in acetonitrile, and a mixture is obtained; adjusting the pH value, adding lauryl amine, dispersing in acetonitrile to obtain a mixed solution, heating and stirring; and b, dropwise adding a phosphorus-containing acidic solution into the step a, heating and stirring, adding melamine, continuously heating and reacting, carrying out solid-liquid separation, and drying to obtain the N-P-containing hybrid modified illite flame retardant. The flame retardant prepared by the preparation method has relatively high thermal stability and flame retardance. The obtained N-P-containing hybrid modified illite flame retardant is applied to epoxy resin, the flame retardant effect on the epoxy resin is excellent, and smoke release and release of smoke and toxic and harmful gas are greatly inhibited.

Description

Technical Field

[0001] The present invention relates to the technical field of flame retardants, and specifically to an N-P hybrid modified illite flame retardant and its preparation method and application. Background Art

[0002] Illite belongs to the family of layered silicates. The basic structural units of layered silicate clay minerals are silicon-oxygen tetrahedrons and aluminum-oxygen octahedrons. It belongs to the monoclinic system and has a spatial structure similar to that of montmorillonite (MMT), belonging to 2:1 layered silicates. The main difference between it and MMT is that the illite sheet size is large and the aspect ratio is high, which is crucial for enhancing the mechanical properties and thermal stability of illite / polymer composites. At the same time, China is rich in mineral resources, and the rational and effective use of mineral resources in the field of flame retardants is the main research direction at present.

[0003] Epoxy resin (EP), as a thermosetting resin, is widely used in many fields such as aerospace, adhesives, engineering materials, and electronic components due to its low cost, high strength, good corrosion resistance, strong adhesion, high insulation, and many other advantages. However, the epoxy groups in EP also cause it to have flammability and poor thermal stability. At the same time, the combustion of EP will also produce a large amount of toxic gases and smoke, and there will be dripping of flames, causing the spread of fire, which also greatly limits the application of EP.

[0004] Organic compounds containing P and N elements have great application prospects in the field of flame retardants. Regarding P-based flame retardants, among all halogen-free flame retardants, phosphorus-containing flame retardants are one of the most promising candidate materials. Due to their low toxicity, high efficiency, multiple flame retardant mechanisms, and molecular diversity, they have been applied to many polymers including EP.

[0005] However, traditional phosphorus- and nitrogen-containing flame retardants have some defects. For example, the flame retardant effect of some flame retardants is not good, or harmful substances will be released during use, posing a potential threat to the environment and human health. Illite has rich reserves and low cost, and it has important research value and practical significance to modify it to prepare high-efficiency flame retardants. Summary of the Invention

[0006] The purpose of the present invention is to provide an N-P hybrid modified illite flame retardant and its preparation method and application to solve the problem of poor flame retardant effect of current illite.

[0007] The present invention is implemented as follows: A preparation method of an N-P hybrid modified illite flame retardant includes the following steps: a. Disperse illite in acetonitrile, adjust the pH to acidic, add dodecylamine, and then heat and stir; b. Drop the phosphorous-containing acidic solution into the mixed solution obtained in step a, heat and stir, then add melamine, continue heating and reacting, separate the solid from the liquid after the reaction, and dry to obtain the N-P hybrid modified illite flame retardant.

[0008] As a further technical solution, in step a, the mass ratio of dodecylamine to illite is 1:8.33 - 1:12.5.

[0009] As a further technical solution, in step a, adjust the pH to 2.5 - 3.5.

[0010] As a further technical solution, in step b, the phosphorous-containing acidic solution is amino trimethylene phosphonic acid, phytic acid or phosphoric acid.

[0011] As a further technical solution, in step b, after adding melamine, the molar ratio of phosphate group to amino group in the solution is 1:1 - 1:3.

[0012] As a further technical solution, in step b, the concentration of the phosphorous-containing acidic solution is 0.01 - 0.03 mol / L.

[0013] As a further technical solution, in step b, the heating reaction temperature is 80 °C and the reaction time is 4 - 8 h.

[0014] The N-P hybrid modified illite flame retardant prepared by the above preparation method can be applied to the preparation of flame retardant materials.

[0015] As a further technical solution, the flame retardant material is epoxy resin.

[0016] When the N-P hybrid modified illite flame retardant prepared by the above preparation method is used in the preparation of epoxy resin, the mass ratio of the N-P hybrid modified illite flame retardant to epoxy resin is 1 - 15:100.

[0017] As a further technical solution, when using the N-P hybrid modified illite flame retardant in the preparation of epoxy resin, the steps include: heat and stir the epoxy resin, add the N-P hybrid modified illite flame retardant thereto, stir evenly, then add m-phenylenediamine thereto, stir evenly, introduce it into a mold and heat for curing, and cool to room temperature to obtain the flame retardant epoxy resin.

[0018] Advantages of the present invention: The present invention uses illite, dodecylamine, melamine and a phosphorus-containing acidic solution as reaction raw materials, that is: after treating illite with dodecylamine, it undergoes a chemical reaction with melamine and a phosphorus-containing acidic solution, and an N-P hybrid modified illite flame retardant is prepared by the method of heating and stirring. This method is simple to operate, has mild conditions, saves energy, has low environmental pollution, and the obtained flame retardant has high thermal stability and flame retardant performance, and has good application prospects in flame retardancy and can be used alone at high temperatures.

[0019] The N-P hybrid modified illite flame retardant prepared by the present invention can be used alone as a flame retardant and added to materials that need to improve flame retardant performance to prepare corresponding flame retardant materials. When it is added to epoxy resin, the flame retardant effect of the obtained flame retardant epoxy resin is greatly improved, and the generation of smoke can be reduced, and the generation of toxic and harmful gases (such as CO, CO2) can be greatly reduced, and it has broad industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 SEM and Mapping images of the flame retardants obtained in Comparative Example 1, Comparative Example 2 and Example 2.

[0021] Figure 2 TG diagrams of the epoxy resin composites prepared in Comparative Example 5, Comparative Example 6 and Example 11.

[0022] Figure 3 Heat release rate (HRR) diagrams of the epoxy resin composites prepared in Comparative Example 5, Comparative Example 6, Example 11 and Example 13 in a cone calorimeter.

[0023] Figure 4 Smoke production rate (SPR) diagrams of the epoxy resin composites prepared in Comparative Example 5, Comparative Example 6, Example 12 and Example 13 in a cone calorimeter.

[0024] Figure 5 Macroscopic char residue diagrams of the epoxy resin composites prepared in Comparative Example 5, Comparative Example 6 and Example 12 in a cone calorimeter. DETAILED DESCRIPTION OF THE INVENTION

[0025] The following further elaborates on the present invention in conjunction with examples. The following examples are only for illustration and do not limit the protection scope of the present invention in any way.

[0026] The processes and methods not described in detail in the following examples are conventional methods well known in the art. The reagents used in the examples are all of analytical purity or chemical purity, and can all be purchased commercially or prepared by methods well known to those of ordinary skill in the art. The following examples have all achieved the purpose of the present invention.

[0027] Melamine used in the following examples was of analytical purity with a purity of 99.5%, purchased from Tianjin Kemiou Chemical Reagent Co., Ltd.; aminotrimethylenephosphonic acid was a 50% solution, purchased from Aladdin Reagent (Shanghai) Co., Ltd.; phytic acid was a 50% solution, purchased from Aladdin Reagent (Shanghai) Co., Ltd.; phosphoric acid was an 85% solution, purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0028] Example 1 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, add 0.1 g of dodecylamine so that the mass ratio of illite to dodecylamine is 10:1. Heat the resulting mixed solution to 80 °C and stir for 12 h. Add 0.01 mol of aminotrimethylenephosphonic acid dropwise to the above solution to make its concentration 0.067 mol / L. After continuing to heat and stir for 1 h, add 0.01 mol of melamine to the above solution so that the molar ratio of phosphate groups to amino groups is 1:1. Continue to heat at 80 °C and react for 4 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0029] Example 2 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, add 0.1 g of dodecylamine so that the mass ratio of illite to dodecylamine is 10:1. Heat the resulting mixed solution to 80 °C and stir for 12 h. Add 0.02 mol of aminotrimethylenephosphonic acid dropwise to the above solution to make its concentration 0.133 mol / L. After continuing to heat and stir for 1 h, add 0.04 mol of melamine to the above solution so that the molar ratio of phosphate groups to amino groups is 1:2. Continue to heat at 80 °C and react for 6 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0030] Comparative Example 1 Compared with Example 2, in this comparative example, acetonitrile was replaced with ethanol, and the others were the same as in Example 2.

[0031] The morphologies of the flame retardants obtained in Example 2 and Comparative Example 1 were tested, and the resulting SEM and Mapping images are as Figure 1 shown. It can be Figure 1 seen that when acetonitrile was used as the solvent, the flame retardant had a good coating effect, while when ethanol was used as the solvent, the coating effect of the resulting flame retardant was very poor.

[0032] Example 3 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, add 0.1 g of dodecylamine to make the mass ratio of illite to dodecylamine 10:1. Heat the resulting mixed solution to 80 °C and stir for 12 h. Add 0.03 mol of aminotrimethylene phosphonic acid to the above solution to make its concentration 0.2 mol / L. After continuing to heat and stir for 1 h, add 0.09 mol of melamine to the above solution to make the molar ratio of phosphate groups to amino groups 1:3. Continue to heat at 80 °C and react for 8 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0033] Example 4 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, add 0.1 g of dodecylamine to make the mass ratio of illite to dodecylamine 10:1. Heat the resulting mixed solution to 80 °C and stir for 12 h. Add 0.01 mol of phytic acid to the above solution to make its concentration 0.067 mol / L. After continuing to heat and stir for 1 h, add 0.02 mol of melamine to the above solution to make the molar ratio of phosphate groups to amino groups 1:1. Continue to heat at 80 °C and react for 4 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0034] Example 5 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, add 0.1 g of dodecylamine to make the mass ratio of illite to dodecylamine 10:1. Heat the resulting mixed solution to 80 °C and stir for 12 h. Add 0.02 mol of phytic acid to the above solution to make its concentration 0.133 mol / L. After continuing to heat and stir for 1 h, add 0.08 mol of melamine to the above solution to make the molar ratio of phosphate groups to amino groups 1:2. Continue to heat at 80 °C and react for 6 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0035] Example 6 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, add 0.1 g of dodecylamine to make the mass ratio of illite to dodecylamine 10:1. Heat the resulting mixed solution to 80 °C and stir for 12 h. Add 0.03 mol of phytic acid to the above solution to make its concentration 0.2 mol / L. After continuing to heat and stir for 1 h, add 0.18 mol of melamine to the above solution to make the molar ratio of phosphate groups to amino groups 1:3. Continue to heat at 80 °C and react for 8 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0036] Example 7 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, add 0.1 g of dodecylamine to make the mass ratio of illite to dodecylamine 10:1. Heat the resulting mixed solution to 80 °C and stir for 12 h. Drop 0.01 mol of phosphoric acid into the above solution to make its concentration 0.067 mol / L. After continuing to heat and stir for 1 h, add 0.0033 mol of melamine to the above solution to make the molar ratio of phosphate group to amino group 1:1. Continue to heat at 80 °C and react for 4 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0037] Example 8 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, add 0.1 g of dodecylamine to make the mass ratio of illite to dodecylamine 10:1. Heat the resulting mixed solution to 80 °C and stir for 12 h. Drop 0.02 mol of phosphoric acid into the above solution to make its concentration 0.133 mol / L. After continuing to heat and stir for 1 h, add 0.0133 mol of melamine to the above solution to make the molar ratio of phosphate group to amino group 1:2. Continue to heat at 80 °C and react for 6 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0038] Example 9 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, add 0.1 g of dodecylamine to make the mass ratio of illite to dodecylamine 10:1. Heat the resulting mixed solution to 80 °C and stir for 12 h. Drop 0.03 mol of phosphoric acid into the above solution to make its concentration 0.2 mol / L. After continuing to heat and stir for 1 h, add 0.03 mol of melamine to the above solution to make the molar ratio of phosphate group to amino group 1:3. Continue to heat at 80 °C and react for 8 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0039] Comparative Example 2 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, drop 0.02 mol of aminotrimethylenephosphonic acid into the above solution to make its concentration 0.133 mol / L. After continuing to heat and stir for 1 h, add 0.04 mol of melamine to the above solution to make the molar ratio of phosphate group to amino group 1:2. Continue to heat at 80 °C and react for 6 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0040] Figure 1The SEM and Mapping diagrams of the flame retardant in Comparative Example 2 are shown. It can be clearly seen that the coating effect of the flame retardant without adding dodecylamine in Comparative Example 2 is very poor. This intuitively reflects that dodecylamine plays a key role in improving the coating performance of the flame retardant.

[0041] Comparative Example 3 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, add 0.02 mol of phytic acid to the above solution to make its concentration 0.133 mol / L. After continuing to heat and stir for 1 h, add 0.08 mol of melamine to the above solution to make the molar ratio of phosphate group to amino group 1:2. Continue to heat and react at 80 °C for 6 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0042] Comparative Example 4 Disperse 1 g of illite in 150 mL of acetonitrile. After adjusting the pH to about 3, add 0.02 mol of phosphoric acid to the above solution to make its concentration 0.133 mol / L. After continuing to heat and stir for 1 h, add 0.0133 mol of melamine to the above solution to make the molar ratio of phosphate group to amino group 1:2. Continue to heat and react at 80 °C for 6 h. After solid-liquid separation, dry for 24 h to obtain the N-P hybrid modified illite flame retardant.

[0043] The yields of the N-P hybrid modified illite flame retardants prepared in the above Examples 1-9 and Comparative Examples 2-4 were calculated, and the results are shown in Table 1 below.

[0044] Table 1 Yield comparison of the products of the present invention From the data in Table 1, it can be seen that the yields of the samples obtained in Examples 1, 4, and 7 are relatively low. Although the yields of the samples in Examples 3, 6, and 9 are higher than those in Examples 1, 4, and 7, they are lower than those in Examples 2, 5, 8 and Comparative Examples 2, 3, 4. It can be seen that the molar ratio of phosphate group to amino group will directly affect the yield.

[0045] The yields of the samples in Examples 2, 5, and 8 were 45.3%, 41.2%, and 39.4% respectively, all higher than those in Comparative Example 2 (38.7%), Comparative Example 3 (38.3%), and Comparative Example 4 (37.2%). It can be seen that after adding dodecylamine to modify illite, the yields of the flame retardants in Examples 2, 5, and 8 were significantly improved. The yield of Example 2 was the highest, indicating that aminotrimethylenephosphonic acid was more conducive to the reaction and promoted the formation of the product. Although the yields of Examples 5 and 8 were slightly lower, they were still better than those of Comparative Examples 2-4. Overall, when the molar ratio of the phosphate group to the amino group was 1:2, modifying illite with dodecylamine had certain advantages in improving the product yield. Compared with Comparative Examples 1, 2, and 3, it could more effectively promote the reaction to proceed in the direction of product formation, providing a feasible solution for increasing the product output in actual production.

[0046] Example 10 Weigh 100 g of epoxy resin into a clean suction flask, heat and stir at 60 °C and 180 rpm for 20 min. Then add 3 g of the flame retardant prepared in Example 2, stir for 20 min to expel air bubbles, add 11.0 g of m-phenylenediamine, and stir for 20 min to ensure that m-phenylenediamine is evenly dispersed; pour into a mold, place in an oven at a vacuum of 0.05 MPa at 60 °C for 20 min, then transfer to an oven at 80 °C and heat for 120 min, adjust the temperature to 150 °C, heat and cure for 220 min. After cooling to room temperature, take out the sample bar to obtain the EP material.

[0047] Example 11 According to the process conditions of Example 10, add 6 g of the flame retardant prepared in Example 2 to the epoxy resin to obtain the corresponding EP material.

[0048] Example 12 According to the process conditions of Example 10, add 9 g of the flame retardant prepared in Example 2 to the epoxy resin to obtain the corresponding EP material.

[0049] Example 13 According to the process conditions of Example 10, add 9 g of the flame retardant prepared in Example 3 to the epoxy resin to obtain the corresponding EP material.

[0050] Comparative Example 5 Weigh 100 g of epoxy resin into a clean suction flask. Under the conditions of 60 °C and 180 rpm, heat and stir for 20 min. Then add 11.0 g of m-phenylenediamine and stir for 20 min to ensure that the curing agent m-phenylenediamine is evenly dispersed. Pour the mixture into a mold and place it in an oven with a vacuum of 0.05 MPa at 60 °C for 20 min. Then transfer it to an oven at 80 °C and heat for 120 min. Adjust the temperature to 150 °C and heat and cure for 220 min. After cooling to room temperature, take out the sample bar to obtain the EP material.

[0051] Comparative Example 6 Weigh 100 g of epoxy resin into a clean suction flask. Under the conditions of 60 °C and 180 rpm, heat and stir for 20 min. Then add 6 g of illite and stir for 20 min to expel air bubbles. Add 11.0 g of m-phenylenediamine and stir for 20 min to ensure that m-phenylenediamine is evenly dispersed. Pour the mixture into a mold and place it in an oven with a vacuum of 0.05 MPa at 60 °C for 20 min. Then transfer it to an oven at 80 °C and heat for 120 min. Adjust the temperature to 150 °C and heat and cure for 220 min. After cooling to room temperature, take out the sample bar to obtain the EP material.

[0052] Experimental method: Limiting oxygen index (LOI): The minimum percentage of oxygen required to maintain the combustion of the sample material in a nitrogen-oxygen mixed gas, which is used to characterize the flame retardancy of the flame retardant. According to the ASTM D2863-2000 standard, it is measured using an HC-2 oxygen index meter (Nanjing Jiangning Analytical Instrument Factory), and the sample size is 140 mm × 6 mm × 3 mm.

[0053] Cone calorimetry (CONE): The cone calorimetry test is measured using icone plus (FTT Company, UK), the sample size is 100 mm × 100 mm × 3 mm, and the irradiation power is 50 kW / m 2 .

[0054] Table 2 Influence of the product of the present invention on the flame retardancy of flame-retardant EP Table 2 shows the comparison of smoke release (SPR) data in the LOI, TGA, and cone calorimetry tests for Examples 10, 11, 12 and Comparative Example 5. From the data in the table, it can be seen that the LOI of pure EP is 22.9 ± 0.2%, indicating that the polymer is flammable. Examples 10, 11, and 12 have a certain degree of improvement compared to Comparative Example 5. When 3 g of the flame retardant in Example 2 was added (Example 10), the LOI of the epoxy resin composite reached 26.8 ± 0.2%, and the LOI gradually increased with the increase in the added amount. When 9 g was added, the LOI of Example 12 reached 28.8 ± 0.2%. This fully demonstrates that the N-P hybrid modified illite flame retardant can effectively improve the flame retardant performance of EP, making it more difficult to burn.

[0055] From the char residue rate data in the TGA test, the char residue rates of Examples 10, 11, and 12 at 800 °C were 21.64 wt%, 24.10 wt%, and 29.57 wt% respectively, all higher than 17.82 wt% of Comparative Example 5. A higher char residue rate means that more char layers can be formed during the combustion process, and these char layers can play a role in blocking heat and oxygen, further inhibiting the combustion of the material. This also reflects the enhancement of the flame retardant performance of EP by the N-P hybrid modified illite flame retardant.

[0056] In terms of smoke release in the cone calorimetry test, the PSPR values of Examples 10, 11, and 12 were 0.383 m² / s, 0.374 m² / s, and 0.303 m² / s respectively, all lower than 0.429 m² / s of Comparative Example 5, indicating that the products of the present invention can effectively reduce the smoke release amount of EP during combustion, reduce the harm caused by smoke, and further improve the smoke suppression effect and safety of EP materials in practical applications.

[0057] In summary, the N-P hybrid modified illite flame retardant can not only significantly increase the LOI of EP and the char residue rate, but also effectively reduce the smoke release amount, comprehensively improving the flame retardant performance and safety of EP, and has important application value and advantages.

[0058] Figure 2 The thermogravimetric test charts and the heat release rate (HRR) in the cone calorimetry test of the epoxy resin composites prepared in Comparative Example 5, Comparative Example 6, and Example 11 are shown. From Figure 2It can be seen that the residual mass of pure EP in Comparative Example 5 is only 17.82%, indicating its poor thermal stability; the residual mass of the EP material obtained after adding 6 g of illite (Comparative Example 6) only reaches 19.58%, while the residual mass of the EP material (Example 11) after adding 6 g of the flame retardant in Example 2 is increased to 24.10%. This change in data fully shows that the flame retardant of the present invention can significantly enhance the thermal stability of epoxy resin composites and enhance the flame retardancy.

[0059] Figure 3 are the heat release rates (HRR) in the cone calorimeter test of the epoxy resin composites prepared in Comparative Example 5, Comparative Example 6, Example 11, and Example 13. From Figure 3 it can be seen that the peak heat release rate (PHRR) of pure EP in Comparative Example 5 reaches 1303 kW / m 2 , and a large amount of heat will be released during combustion, which is extremely likely to cause the rapid spread of fire and pose a great potential safety hazard; for the EP composite material (Comparative Example 6) obtained after adding 6 g of illite, the PHRR is reduced to 1123.34 kW / m 2 , but compared with Example 11 with 6 g of the flame retardant in Example 2 added, the PHRR of Example 11 is reduced to 895 kW / m 2 , which is reduced by 31.31% compared to pure EP. This significant reduction fully proves that the flame retardant of the present invention can efficiently inhibit the heat release of epoxy resin composites during combustion, effectively reduce the risk level during a fire, and bring a qualitative improvement to the fire safety performance of the material. In addition, the PHRR of the EP composite material (corresponding to Example 13) with 9 g of the flame retardant in Example 3 added is 973.8 kW / m 2 , which is slightly increased compared to the PHRR in Example 11. For the EP composite materials after adding 9 g of the flame retardants in Example 6 or Example 9, their effects are not much different from those in Example 13.

[0060] Figure 4 shows the smoke production rates (SPR) of the epoxy resin composites prepared in Comparative Example 5, Comparative Example 6, Example 12, and Example 13 in the cone calorimeter test. From Figure 4 it can be seen that the peak smoke production rate (PSPR) of (pure epoxy resin) in Comparative Example 5 is 0.429 m 2 / s. After adding 6 g of illite, the PSPR of the obtained EP material (corresponding to Comparative Example 6) is reduced to 0.393 m 2 / s. After adding 9 g of the flame retardant in Example 3 to the EP composite material (corresponding to Example 13), the PSPR is reduced to 0.330 m 2 / s. After adding 9 g of the flame retardant in Example 2, the PSPR of the obtained EP composite material (corresponding to Example 12) decreased to 0.303 m 2 / s, and the reduction amplitude reached 30.07%, showing a good smoke suppression effect. In addition, the PSPR of the EP composite material after adding 9 g of the flame retardant in Example 6 or Example 9 was not much different from that in Example 13.

[0061] Figure 5 Figure 6 shows the macroscopic char residue diagrams of the cone calorimeter tests for Comparative Example 5, Comparative Example 6, and Example 12. It can be seen that the char residue amount in Example 12 has increased significantly compared to Comparative Example 5. A higher char residue amount means that during the combustion process, the material can form a more stable char layer structure. This char layer can not only act as a physical barrier to block the transfer of heat and oxygen into the material interior, slowing down the combustion process, but also inhibit the release of combustible gases, further enhancing the flame retardant performance of the material.

[0062] From the above, it can be concluded that the N-P hybrid modified illite flame retardant prepared by the present invention has a good flame retardant and smoke suppression effect, can comprehensively improve the flame retardancy and safety of EP, and has important application value and advantages.

Claims

1. A preparation method of an N-P hybrid modified illite flame retardant, characterized in that The following steps are involved: a. Disperse illite in acetonitrile, adjust the pH to acidic, add dodecylamine, and then heat and stir; b. Add the phosphorus-containing acidic solution dropwise to the mixed solution obtained in step a, heat and stir, then add melamine, continue heating and reacting, separate the solid and liquid after the reaction is completed, and dry to obtain the NP-containing hybrid modified illite flame retardant.

2. The preparation method of the N-P hybrid modified illite flame retardant according to claim 1, characterized in that, In step a, the mass ratio of dodecylamine to illite is 1:8.33 to 1:12.

5.

3. The preparation method of the N-P hybrid modified illite flame retardant according to claim 2, characterized in that, In step a, adjust the pH to 2.5-3.

5.

4. The preparation method of the N-P hybrid modified illite flame retardant according to claim 1, characterized in that, In step b, the phosphorus-containing acidic solution is aminotrimethylphosphonic acid, phytic acid or phosphoric acid.

5. The preparation method of the N-P hybrid modified illite flame retardant according to claim 1, characterized in that, In step b, after adding melamine, the molar ratio of phosphate groups to amino groups in the solution is 1:1 to 1:

3.

6. The preparation method of the N-P hybrid modified illite flame retardant according to claim 5, characterized in that, In step b, after adding melamine, the molar ratio of phosphate groups to amino groups in the solution is 1:

2.

7. The NP hybrid modified illite flame retardant prepared by the method according to any one of claims 1 to 6.

8. Use of the NP hybrid modified illite flame retardant according to claim 7 in the preparation of flame retardant materials.

9. The application according to claim 8, characterized in that, The flame retardant material is epoxy resin.

10. The application according to claim 9, characterized in that, The mass ratio of NP hybrid modified illite flame retardant to epoxy resin is 1~15:100.

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