SiO2 aerogel-based flame retardant modified PA66 material and preparation method thereof

Abstract

The invention belongs to the technical field of material science, and particularly relates to a SiO2 aerogel-based flame retardant modified PA66 material and a preparation method thereof. The preparation method comprises the following steps: adding melamine, diphenyl phosphoric acid, tris (2-ethylhexyl) phosphate and SiO2 aerogel into water, carrying out ultrasonic treatment to obtain a mixed solution, heating and stirring the mixed solution, cooling, washing to be neutral, adding metal salt, stirring, precipitating the product, and drying to obtain the SiO2 aerogel-based flame retardant. The preparation method comprises the following steps: mixing a SiO2 aerogel-based flame retardant and an adhesive to obtain slurry, and drying, curing and the like the slurry to obtain a modified SiO2 aerogel-based flame retardant; and mixing the modified SiO2 aerogel-based flame retardant with a PA66 material, drying, and carrying out melt extrusion through a twin-screw extruder to obtain the flame-retardant PA66 composite material. The modified SiO2 aerogel-based flame retardant disclosed by the invention can be used for effectively improving the flame retardant property of a spinning-grade PA66 material.

Description

Technical Field

[0001] The present invention belongs to the field of material science and technology and specifically relates to a SiO 2 Aerogel-based flame retardant modified PA66 material and preparation method thereof. Background Art

[0002] With the rapid development of science and technology, the demand for materials with good comprehensive performance and flame retardant properties in the fields of automobiles, electronics and electrical engineering is increasing. Currently, more and more researchers are committed to studying materials with flame retardant properties to meet the market demand for safe and high-performance materials.

[0003] PA66 is a thermoplastic resin that has been widely used in machinery, electronics and electrical fields due to its excellent mechanical properties and heat resistance. However, traditional PA66 materials are flammable and burn quickly in fire situations, releasing toxic gases accompanied by severe molten dripping, which poses a safety hazard and greatly limits its scope of application.

[0004] Therefore, it is of great practical significance to develop an effective flame retardant to improve the flame retardant properties of spinning-grade PA66 materials without damaging the properties of PA66 itself. Summary of the invention

[0005] One of the purposes of the present invention is to provide a SiO 2 The invention discloses a method for preparing an aerogel-based flame retardant-modified PA66 material. The preparation method is simple, low-cost and suitable for industrial production.

[0006] The second object of the present invention is to provide a SiO 2 Aerogel-based flame retardant modified PA66 material, SiO prepared by the present invention 2 Aerogel-based flame retardants have high porosity and high specific surface area, and can effectively improve the flame retardant properties of spinning-grade PA66 materials.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A SiO 2 The preparation method of aerogel-based flame retardant modified PA66 material comprises the following steps:

[0009] (1) Melamine, diphenylphosphoric acid, tri(2-ethylhexyl) phosphate, SiO 2 The aerogel is added to water and ultrasonically treated to obtain a mixed solution. The mixed solution is heated and stirred, then cooled, washed to neutrality, and a metal salt is added and stirred. The product is precipitated and dried to obtain SiO 2 Aerogel-based flame retardants;

[0010] (2) SiO2 The aerogel-based flame retardant and the adhesive are mixed to obtain a slurry, and the slurry is dried and cured to obtain a modified SiO 2 Aerogel-based flame retardants;

[0011] (3) Modified SiO 2 The aerogel-based flame retardant is mixed with the PA66 material and dried, and then melt-extruded through a twin-screw extruder to obtain the aerogel-based flame retardant.

[0012] Furthermore, the metal salt in step (1) is at least one of zinc nitrate, manganese acetate tetrahydrate, nickel acetate tetrahydrate, and anhydrous aluminum chloride.

[0013] Furthermore, in step (1), melamine, diphenylphosphoric acid, tri(2-ethylhexyl) phosphate, SiO 2 The usage ratio of aerogel and metal salt is 1.5-2g:1-1.5mL:1-1.5mL:0.5-0.8g:0.01mol.

[0014] Furthermore, the heating and stirring in step (1) is performed at a temperature of 90-100° C. and for a time of 9-11 hours.

[0015] Furthermore, the adhesive in step (2) is one of γ-aminopropyltriethoxysilane, dodecyltrimethylammonium bromide, polyvinylpyrrolidone, γ-mercaptopropyltrimethoxysilane, and sodium dodecyl sulfate.

[0016] Furthermore, in step (2), the SiO 2 The mass percentage of the aerogel-based flame retardant in the slurry is 5-15%, and the mass percentage of the binder in the slurry is 85-95%.

[0017] Furthermore, the PA66 material in step (3) is spinning grade PA66 with a relative viscosity of 2.55-2.70.

[0018] Furthermore, in step (3), the modified SiO 2 The mass ratio of aerogel-based flame retardant to PA66 material is 1:(5.66-19).

[0019] Furthermore, during the melt extrusion process in step (3), the temperatures of the screw zones are 240° C., 250° C., 260° C., 265° C., and 270° C., respectively, and the screw speed is 20 r / min.

[0020] A SiO 2 The aerogel-based flame retardant modified PA66 material is prepared according to the above preparation method.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention provides a SiO 2 Aerogel-based flame retardant modified PA66 material. The present invention uses SiO 2 Aerogel was mixed with melamine, diphenylphosphoric acid, tri(2-ethylhexyl) phosphate and a series of metal salts in different proportions to react with the metal ion chelation method on SiO 2 The surface of the aerogel forms a coating layer to obtain SiO 2 Aerogel-based flame retardant; then the SiO 2 Aerogel-based flame retardant surface modification to obtain modified SiO 2 Aerogel-based flame retardant, making modified SiO 2 Aerogel-based flame retardant forms hydrogen bonds with the amide bonds in the PA66 macromolecular chain segments, and can also react with the amino and carboxyl groups at the ends of the PA66 molecular chains to form covalent bonds, increasing the SiO 2 The interfacial adhesion and compatibility between the aerogel-based flame retardant and the PA66 substrate ensure its uniform dispersion and modification effect in the PA66 substrate.

[0023] 2. SiO prepared by the present invention 2 Aerogel-based flame retardants have high porosity and high specific surface area, which can effectively improve the flame retardant properties of spinning-grade PA66 materials. 2 Aerogel-based flame retardants are nano-sized and have uniform particle size. They can be used in the PA66 spinning process without clogging the spinneret holes.

[0024] 3. The present invention provides a SiO 2 The invention discloses a method for preparing an aerogel-based flame retardant-modified PA66 material. The preparation method is simple, low-cost and suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The SiO obtained in Example 1 of the present invention 2 TEM image of aerogel-based flame retardant;

[0026] Figure 2 The SiO obtained in Example 1 of the present invention 2 Surface SEM image of aerogel-based flame retardant modified PA66 material;

[0027] Figure 3 The SiO obtained in Example 1 of the present invention 2 Cross-sectional SEM image of aerogel-based flame retardant modified PA66 material;

[0028] Figure 4 The SiO 2 Thermogravimetric curves of aerogel-based flame retardants. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further explained below in conjunction with specific embodiments, comparative examples, test examples and drawings.

[0030] In the following examples, comparative examples and test examples, the raw materials and preparation methods used are all conventional materials and techniques in the art unless otherwise specified. The PA66 material in the present invention is spinning grade PA66 with a relative viscosity of 2.55-2.70.

[0031] Preparation Example

[0032] SiO 2 Preparation of aerogel: TEOS, anhydrous ethanol and deionized water were mixed in a molar ratio of 1:7:3 and stirred rapidly at 25°C for 30 min. Then, 1 mol / L hydrochloric acid was added dropwise to adjust the pH to 2, and then ultrasonic hydrolysis was performed for 60 min. After that, 0.5 mol / L ammonia water was added dropwise to adjust the pH to 7, and the aerogel was allowed to stand at 25°C for 10 min. Finally, the aerogel was dried in an oven at 50°C for 24 h, the solvent was replaced with n-hexane, and then dried at 80°C for 8 h.

[0033] Example 1

[0034] A SiO 2 The preparation method of aerogel-based flame retardant modified PA66 material comprises the following steps:

[0035] (1) Melamine (1.893 g), diphenylphosphoric acid (1.12 mL), tri(2-ethylhexyl) phosphate (1.12 mL), SiO 2 Aerogel (0.6012 g) was dispersed in 200 mL of distilled water and ultrasonically treated for 0.5 h to obtain a mixed solution. The mixed solution was stirred at 95 °C and 400 r / min for 10 h, then cooled to room temperature and washed with distilled water until neutral. 0.01 mol of zinc nitrate was added and stirred at 40 °C for 4 h. After the product was precipitated, it was dried at 80 °C to obtain SiO 2 Aerogel-based flame retardant, named MPA-Zn;

[0036] (2) SiO 2 Aerogel-based flame retardant (MPA-Zn) and γ-aminopropyltriethoxysilane (KH550) were mixed to obtain a uniform slurry, in which SiO 2 The mass percentage of the aerogel-based flame retardant in the slurry is 5%, and the balance is KH550. The slurry is dried and cured at 80°C to obtain modified SiO 2 Aerogel-based flame retardants;

[0037] (3) Modified SiO 2The aerogel-based flame retardant and the PA66 material were mixed at a mass ratio of 1:9, and then placed in a vacuum drum dryer and dried at 160°C for 8 hours. Finally, the flame retardant was evenly dispersed in the PA66 substrate by melt extrusion through a twin-screw extruder, wherein the temperatures of the screw zones were 240°C, 250°C, 260°C, 265°C, and 270°C, and the screw speed was 20r / min;

[0038] This embodiment also provides a SiO 2 The aerogel-based flame retardant modified PA66 material is prepared by adopting the above preparation method.

[0039] Example 2

[0040] A SiO 2 The preparation method of aerogel-based flame retardant modified PA66 material comprises the following steps:

[0041] (1) Melamine (1.5 g), diphenylphosphoric acid (1 mL), tri(2-ethylhexyl) phosphate (1 mL), SiO 2 Aerogel (0.5 g) was dispersed in 200 mL of distilled water and ultrasonically treated for 0.5 h to obtain a mixed solution. The mixed solution was stirred at 95 °C and 400 r / min for 11 h, then cooled to room temperature and washed with distilled water until neutral. 0.01 mol of manganese acetate tetrahydrate was added and stirred at 40 °C for 4 h. After the product was precipitated, it was dried at 80 °C to obtain SiO 2 Aerogel-based flame retardant, named MPA-Mn;

[0042] (2) SiO 2 Aerogel-based flame retardant (MPA-Mn) and dodecyltrimethylammonium bromide (DTAB) were mixed to obtain a uniform slurry, in which SiO 2 The mass percentage of the aerogel-based flame retardant in the slurry is 10%, and the balance is DTAB; the slurry is dried and cured at 80°C to obtain a modified SiO 2 Aerogel-based flame retardants;

[0043] (3) Modified SiO 2 The aerogel-based flame retardant and the PA66 material were mixed at a mass ratio of 1:19, and then placed in a vacuum drum dryer and dried at 170°C for 6 hours. Finally, the flame retardant was evenly dispersed in the PA66 substrate by melt extrusion through a twin-screw extruder, wherein the temperatures of the screw zones were 240°C, 250°C, 260°C, 265°C, and 270°C, and the screw speed was 20r / min;

[0044] This embodiment also provides a SiO 2The aerogel-based flame retardant modified PA66 material is prepared by adopting the above preparation method.

[0045] Example 3

[0046] A SiO 2 The preparation method of aerogel-based flame retardant modified PA66 material comprises the following steps:

[0047] (1) Melamine (2 g), diphenylphosphoric acid (1.5 mL), tri(2-ethylhexyl) phosphate (1.5 mL), SiO 2 Aerogel (0.8 g) was dispersed in 200 mL of distilled water and ultrasonically treated for 0.5 h to obtain a mixed solution. The mixed solution was stirred at 100 °C and 400 r / min for 9 h, then cooled to room temperature and washed with distilled water until neutral. 0.01 mol of nickel acetate tetrahydrate was added and stirred at 40 °C for 4 h. After the product was precipitated, it was dried at 80 °C to obtain SiO 2 aerogel-based flame retardant, named MPA-Ni;

[0048] (2) SiO 2 The aerogel-based flame retardant (MPA-Ni) and sodium dodecyl sulfate were mixed to obtain a uniform slurry, in which SiO 2 The mass percentage of the aerogel-based flame retardant in the slurry is 15%, and the balance is sodium dodecyl sulfate; the slurry is dried and cured at 80°C to obtain modified SiO 2 Aerogel-based flame retardants;

[0049] (3) Modified SiO 2 The aerogel-based flame retardant and the PA66 material were mixed at a mass ratio of 1:5.66, and then placed in a vacuum drum dryer and dried at 180°C for 4 hours. Finally, the flame retardant was evenly dispersed in the PA66 substrate by melt extrusion through a twin-screw extruder, wherein the temperatures of the screw zones were 240°C, 250°C, 260°C, 265°C, and 270°C, and the screw speed was 20r / min;

[0050] This embodiment also provides a SiO 2 The aerogel-based flame retardant modified PA66 material is prepared by adopting the above preparation method.

[0051] Example 4

[0052] A SiO 2 The preparation method of aerogel-based flame retardant modified PA66 material comprises the following steps:

[0053] (1) Melamine (1.893 g), diphenylphosphoric acid (1.12 mL), tri(2-ethylhexyl) phosphate (1.12 mL), SiO 2 Aerogel (0.6012 g) was dispersed in 200 mL of distilled water and ultrasonically treated for 0.5 h to obtain a mixed solution. The mixed solution was stirred at 95 °C and 400 r / min for 10 h, then cooled to room temperature and washed with distilled water until neutral. 0.01 mol of anhydrous aluminum chloride was added and stirred at 40 °C for 4 h. After the product was precipitated, it was dried at 80 °C to obtain SiO 2 aerogel-based flame retardant, named MPA-Al;

[0054] (2) SiO 2 The aerogel-based flame retardant (MPA-Al) and 10% polyvinyl pyrrolidone (PVP) aqueous solution were mixed to obtain a uniform slurry, in which SiO 2 The mass percentage of the aerogel-based flame retardant in the slurry is 10%, and the remainder is a PVP aqueous solution; the slurry is dried and cured at 80°C to obtain a modified SiO 2 Aerogel-based flame retardants;

[0055] (3) Modified SiO 2 The aerogel-based flame retardant and the PA66 material were mixed at a mass ratio of 1:5.66, and then placed in a vacuum drum dryer and dried at 180°C for 4 hours. Finally, the flame retardant was evenly dispersed in the PA66 substrate by melt extrusion through a twin-screw extruder, wherein the temperatures of the screw zones were 240°C, 250°C, 260°C, 265°C, and 270°C, and the screw speed was 20r / min;

[0056] This embodiment also provides a SiO 2 The aerogel-based flame retardant modified PA66 material is prepared by adopting the above preparation method.

[0057] Example 5

[0058] A SiO 2 The preparation method of aerogel-based flame retardant modified PA66 material comprises the following steps:

[0059] (1) MPA-Zn was prepared according to the method of Example 1, and MPA-Al was prepared according to the method of Example 4;

[0060] (2) SiO 2 Aerogel-based flame retardants (MPA-Zn and MPA-Al) were mixed with KH550 to obtain a uniform slurry, in which SiO 2The mass percentage of aerogel-based flame retardants MPA-Zn and MPA-Al in the slurry is 5%, and the balance is KH550; the slurry is dried and cured at 80°C to obtain modified SiO 2 Aerogel-based flame retardants;

[0061] (3) Modified SiO 2 The aerogel-based flame retardant and the PA66 material were mixed at a mass ratio of 1:5.66, and then placed in a vacuum drum dryer and dried at 180°C for 4 hours. Finally, the flame retardant was evenly dispersed in the PA66 substrate by melt extrusion through a twin-screw extruder, wherein the temperatures of the screw zones were 240°C, 250°C, 260°C, 265°C, and 270°C, and the screw speed was 20r / min;

[0062] This embodiment also provides a SiO 2 The aerogel-based flame retardant modified PA66 material is prepared by adopting the above preparation method.

[0063] Example 6

[0064] A SiO 2 The preparation method of aerogel-based flame retardant modified PA66 material comprises the following steps:

[0065] (1) Melamine (1.893 g), diphenylphosphoric acid (1.12 mL), tri(2-ethylhexyl) phosphate (1.12 mL), SiO 2 Aerogel (0.6012 g) was dispersed in 200 mL of distilled water and ultrasonically treated for 0.5 h to obtain a mixed solution. The mixed solution was stirred at 95 °C and 400 r / min for 10 h, then cooled to room temperature and washed with distilled water until neutral. 0.005 mol of zinc nitrate and 0.005 mol of anhydrous aluminum chloride were added, stirred at 40 °C for 4 h, and the product was precipitated and dried at 80 °C to obtain SiO 2 Aerogel-based flame retardant, named MPA-Zn-Al;

[0066] (2) SiO 2 The aerogel-based flame retardant (MPA-Zn-Al) and γ-mercaptopropyltrimethoxysilane were mixed to obtain a uniform slurry, in which SiO 2 The mass percentage of the aerogel-based flame retardant in the slurry is 10%, and the balance is a binder; the slurry is dried and cured at 80°C to obtain a modified SiO 2 Aerogel-based flame retardants;

[0067] (3) Modified SiO 2The aerogel-based flame retardant and the PA66 material were mixed at a mass ratio of 1:9, and then placed in a vacuum drum dryer and dried at 170°C for 4 hours. Finally, the flame retardant was evenly dispersed in the PA66 substrate by melt extrusion through a twin-screw extruder, wherein the temperatures of the screw zones were 240°C, 250°C, 260°C, 265°C, and 270°C, and the screw speed was 20r / min;

[0068] This embodiment also provides a SiO 2 The aerogel-based flame retardant modified PA66 material is prepared by adopting the above preparation method.

[0069] Comparative Example 1

[0070] This comparative example 1 is basically the same as Example 1, except that: in this comparative example 1, the addition of zinc nitrate is omitted in step (1), and the flame retardant prepared in step (1) is recorded as MPA. The rest is consistent with Example 1.

[0071] Comparative Example 2

[0072] This comparative example 2 is basically the same as Example 1, except that: this comparative example 2 omits step (1) and replaces SiO 2 The aerogel-based flame retardant (MPA-Zn) was replaced by SiO 2 Aerogel, and other aspects are consistent with those in Example 1.

[0073] Comparative Example 3

[0074] This comparative example 3 is basically the same as Example 1, except that step (2) is to convert SiO 2 Aerogel-based flame retardant (MPA-Zn), γ-aminopropyltriethoxysilane and PA66 material were directly mixed, and then placed in a vacuum drum dryer and dried at 160°C for 8 hours. Finally, the flame retardant was evenly dispersed in the PA66 substrate by melt extrusion through a twin-screw extruder, wherein the temperatures of each zone of the screw were 240°C, 250°C, 260°C, 265°C, and 270°C, and the screw speed was 20r / min;

[0075] Comparative Example 4

[0076] This comparative example 4 is basically the same as Example 1, except that in this comparative example 4, zinc nitrate in step (1) is replaced by copper sulfate to prepare SiO 2 The aerogel-based flame retardant is named MPA-Cu, and the rest is consistent with Example 1.

[0077] Comparative Example 5

[0078] This comparative example 5 is basically the same as Example 1, except that in this comparative example 5, the zinc nitrate in step (1) is replaced by anhydrous ferric chloride to prepare SiO 2 The aerogel-based flame retardant is named MPA-Fe, and the rest is consistent with Example 1.

[0079] Test Case

[0080] from Figure 1 Example 1 SiO 2 The TEM image of the aerogel-based flame retardant shows that the SiO 2 Aerogel-based flame retardants are nano-sized and have uniform particle size. They can be used in the PA66 spinning process without clogging the spinneret holes.

[0081] from Figure 2 Example 1 SiO 2 From the surface SEM image of aerogel-based flame retardant modified PA66 material, it can be seen that the surface of the modified spinning-grade PA66 material is relatively smooth. Figure 3 The SiO obtained in Example 1 2 Cross-sectional SEM image of aerogel-based flame retardant modified PA66 material. Figure 3 It can be seen that the PA66 sample exhibits ductile fracture.

[0082] For the above groups of SiO 2 The thermal weight loss of aerogel-based flame retardant was tested. The specific test process was as follows: 3 mg of sample was weighed and heated at N 2 The temperature was raised from 30°C to 800°C at a rate of 10°C / min. Figure 4 .

[0083] Figure 4 For the above groups of SiO 2 The thermal weight loss of aerogel-based flame retardant. In contrast, the SiO 2 The aerogel-based flame retardant has minimal mass loss after calcination at 800 °C.

[0084] The SiO 2 The aerogel-based flame retardant modified PA66 material was subjected to a combustion test and a tensile property test. The test results are shown in Tables 1 and 2 below, respectively.

[0085] Table 1 SiO 2 Aerogel-based flame retardant modified PA66 specimen combustion test data

[0086]

[0087] Table 2SiO 2Mechanical properties test results of PA66 strips modified with aerogel-based flame retardant

[0088] Group Tensile strength / MPa Elongation at break / % Example 1 59.58 228 Example 2 55.69 270 Example 3 59.82 282 Example 4 55.83 302 Example 5 60.90 350 Example 6 58.93 239 Comparative Example 1 59.85 206 Comparative Example 2 59.60 198 Comparative Example 3 57.45 219 Comparative Example 4 54.87 211 Comparative Example 5 55.31 219

[0089] It can be seen from Table 1 that the SiO 2 The flame retardant properties of the PA66 material modified by the aerogel-based flame retardant are significantly better than those of Comparative Examples 1-3, indicating that the modified SiO 2 Aerogel flame retardant can significantly improve the flame retardant properties of PA66.

[0090] By comparing Example 1, Comparative Example 1 and Comparative Example 2, it can be seen that simply adding SiO to the spinning grade PA66 material 2 Aerogel cannot improve the flame retardant properties of PA66. SiO2 is modified with melamine, diphenyl phosphate and (2-ethylhexyl) ester. 2 After aerogel, it is added to spinning grade PA66 material, the flame retardant performance of PA66 is improved, but molten droplets will still be produced. SiO2 modified by melamine, diphenyl phosphate, tri(2-ethylhexyl) phosphate and metal salt chelation 2 Aerogel-based flame retardants can significantly improve the droplet phenomenon of PA66.

[0091] Compared with Example 1, Comparative Example 3 changed the order of adding the adhesives, and the final product still produced a droplet phenomenon, and the flame retardant performance was not as good as that of Example 1, indicating that the order of adding the adhesives would affect the SiO 2 The compatibility of aerogel-based flame retardants with PA66 affects its overall performance.

[0092] It can be seen from Table 1 and Table 2 that compared with Example 1 (single MPA-Zn aerogel flame retardant modified spinning grade PA66), the loss length of PA66 modified by MPA-Al and MPA-Zn mixed aerogel-based flame retardant in Example 5 after combustion is smaller; the breaking strength of PA66 modified by MPA-Al and MPA-Zn mixed aerogel-based flame retardant does not change significantly, but the elongation at break is significantly increased. Comparing Example 5 and Example 6, it can be seen that the effect of MPA-Zn-Al aerogel-based flame retardant on the flame retardant properties, breaking strength and elongation at break of spinning grade PA66 materials is slightly lower than the effect of MPA-Al and MPA-Zn mixed aerogel-based flame retardant on the properties of spinning grade PA66 materials.

[0093] The above are only preferred embodiments of the present invention, and are not limited to the above examples. For those skilled in the art, various changes and variations are possible under the principle of the present invention. Any modifications and improvements made should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a SiO2 aerogel-based flame retardant-modified PA66 material, characterized in that: The steps include: (1) adding melamine, diphenylphosphoric acid, tri(2-ethylhexyl) phosphate and SiO2 aerogel into water and subjecting the mixture to ultrasonic treatment to obtain a mixed solution, heating and stirring the mixed solution, cooling the mixed solution, washing the mixed solution to neutrality, adding a metal salt and subjecting the mixture to stirring, and drying the product after precipitation to obtain a SiO2 aerogel-based flame retardant; (2) mixing a SiO2 aerogel-based flame retardant and a binder to obtain a slurry, and drying and curing the slurry to obtain a modified SiO2 aerogel-based flame retardant; (3) The modified SiO2 aerogel-based flame retardant is mixed with the PA66 material and dried, and then melt-extruded through a twin-screw extruder to obtain the obtained product.

2. The method for preparing the SiO2 aerogel-based flame retardant modified PA66 material according to claim 1, characterized in that: The metal salt in step (1) is at least one of zinc nitrate, manganese acetate tetrahydrate, nickel acetate tetrahydrate, and anhydrous aluminum chloride.

3. The method for preparing the SiO2 aerogel-based flame retardant modified PA66 material according to claim 1, characterized in that: The usage ratio of melamine, diphenylphosphoric acid, tri(2-ethylhexyl) phosphate, SiO2 aerogel and metal salt in step (1) is 1.5-2g:1-1.5mL:1-1.5mL:0.5-0.8g:0.01mol.

4. The method for preparing the SiO2 aerogel-based flame retardant modified PA66 material according to claim 1, characterized in that: The heating and stirring in step (1) is carried out at a temperature of 90-100° C. and for a time of 9-11 hours.

5. The method for preparing the SiO2 aerogel-based flame retardant modified PA66 material according to claim 1, characterized in that: The adhesive in step (2) is one of γ-aminopropyltriethoxysilane, dodecyltrimethylammonium bromide, polyvinylpyrrolidone, γ-mercaptopropyltrimethoxysilane and sodium dodecyl sulfate.

6. The method for preparing SiO2 aerogel-based flame retardant modified PA66 material according to claim 1, characterized in that: In step (2), the mass percentage of the SiO2 aerogel-based flame retardant in the slurry is 5-15%, and the remainder is a binder.

7. The method for preparing SiO2 aerogel-based flame retardant modified PA66 material according to claim 1, characterized in that: The PA66 material in step (3) is spinning grade PA66 with a relative viscosity of 2.55-2.

70.

8. The method for preparing SiO2 aerogel-based flame retardant modified PA66 material according to claim 1, characterized in that: The mass ratio of the modified SiO2 aerogel-based flame retardant to the PA66 material in step (3) is 1:(5.66-19).

9. The method for preparing SiO2 aerogel-based flame retardant modified PA66 material according to claim 1, characterized in that: During the melt extrusion process in step (3), the temperatures of the screw zones are 240°C, 250°C, 260°C, 265°C, and 270°C, respectively, and the screw speed is 20r / min.

10. A SiO2 aerogel-based flame retardant modified PA66 material, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 9.

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