Highly flame-retardant PA66 composite material and preparation method thereof

Abstract

This invention discloses a high flame-retardant PA66 composite material and its preparation method. PA66 masterbatch, flame-retardant additives, maleic anhydride-grafted polyolefin elastomers, and montmorillonite are added to a twin-screw extruder and melt-extruded to obtain the high flame-retardant PA66 composite material. The flame-retardant additive molecules contain active amino groups, which can undergo amidation reactions with the terminal carboxyl groups of the PA66 molecular chain during melt blending, firmly anchoring the entire large flame-retardant molecule to the PA66 matrix in the form of chemical bonds. The DOPO group decomposes to release PO· free radicals, which efficiently capture H· and OH· in the combustion chain reaction. The POSS cage collapses during combustion to form a dense nanoscale silica protective layer, promoting char-forming condensed phase. The polysiloxane segments can provide silicon sources, enhancing the flexibility and thickness of the char layer and synergistically forming char. Montmorillonite forms a micron-scale lamellar char skeleton, which improves the density and stability of the char.

Description

Technical Field

[0001] This invention relates to the field of high flame retardant PA66 composite material and its preparation method. Background Technology

[0002] Polyhexamethylene adipamide (PA66), an important engineering plastic, is widely used in high-end manufacturing fields such as automotive parts, electronics, rail transportation, and aerospace due to its excellent mechanical strength, heat resistance, wear resistance, and chemical corrosion resistance. However, PA66 itself is a flammable material with a limiting oxygen index of only about 23%-24%, allowing it to continue burning in air with severe molten dripping during combustion. This fatal flaw greatly limits the application of PA66 in scenarios with stringent flame retardant safety requirements. Therefore, developing highly flame-retardant and anti-dripping PA66 composite materials has significant practical and commercial value. Summary of the Invention

[0003] The purpose of this invention is to provide a high flame-retardant PA66 composite material and its preparation method, which solves the problems of poor flame retardant effect and easy dripping of current PA66 materials.

[0004] The objective of this invention can be achieved through the following technical solutions: A method for preparing a high flame-retardant PA66 composite material specifically includes the following steps: PA66 masterbatch, flame retardant additives, maleic anhydride-grafted polyolefin elastomer, and montmorillonite are added to a twin-screw extruder and melt-extruded under the following conditions: feeding section temperature 240-250℃, compression section temperature 260-270℃, metering section temperature 270-280℃, and die head temperature 265-275℃, to obtain a high flame retardant PA66 composite material.

[0005] Furthermore, the weight ratio of PA66 masterbatch, flame retardant additive, maleic anhydride grafted polyolefin elastomer and montmorillonite is 100-120:10-15:10-12:1-2.

[0006] Furthermore, the flame retardant additive is prepared by the following steps: Step A1: Mix octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, purge with nitrogen, and react for 3-5 hours at a rotation speed of 150-200 r / min and a temperature of 90-95℃. Then raise the temperature to 140-145℃ and react for 1-1.5 hours to obtain functionalized polysiloxane. Step A2: Mix functionalized polysiloxane, DOPO and toluene evenly, purge with nitrogen for protection, stir and add azobisisobutyronitrile at a speed of 200-300 r / min and a temperature of 80-90℃, and react for 12-15 h to obtain pretreated polysiloxane. Step A3: Mix the modified cage-type silsesquioxane and tetrahydrofuran, stir and add pretreated polysiloxane at a speed of 300-500 r / min and a temperature of 20-25℃, heat to 45-55℃, add triethylamine, react for 6-8 h, add DOPO, heat to 60-70℃, and continue to react for 4-6 h to obtain the flame retardant additive.

[0007] Furthermore, the molar ratio of octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane in step A1 is 10:1:0.02:1.

[0008] Furthermore, the molar ratio of the double bond, DOPO, and azobisisobutyronitrile on the functionalized polysiloxane described in step A2 is 2:2.1:0.04.

[0009] Furthermore, the molar ratio of the modified cage-like silsesquioxane, the pretreated polysiloxane, and DOPO in step A3 is 1:1:1.1, and the amount of triethylamine used is 0.5% of the mass of the modified cage-like silsesquioxane and the pretreated polysiloxane.

[0010] Furthermore, the modified cage-like silsesquioxane is prepared by the following steps: Step B1: Mix phenyltrimethoxysilane, sodium hydroxide, deionized water and tetrahydrofuran, and react at 120-150 r / min and 70-75℃ for 5-7 hours. Then, cool to 20-25℃ and react for 10-15 hours to obtain trisodium heptaphenylsiloxane. Mix trisodium heptaphenylsiloxane, triethylamine and tetrahydrofuran, and stir at 150-200 r / min and 0℃ while adding trichlorosilane. React for 3-5 hours, then heat to 20-25℃ and react for 20-25 hours to obtain heptaphenylcage-type silsesquioxane. Step B2: Mix heptaphenyl cage-like silsesquioxane, acrolein diethanol, caster catalyst, and tetrahydrofuran, and purge with nitrogen. React at 200-300 r / min and 80-85℃ for 6-8 hours to obtain pretreated cage-like silsesquioxane. Dissolve the pretreated cage-like silsesquioxane in tetrahydrofuran, and stir while adding p-toluenesulfonic acid aqueous solution at 150-200 r / min and 20-25℃. React for 2-4 hours, then add sodium bicarbonate to neutralize, to obtain modified cage-like silsesquioxane.

[0011] Furthermore, the ratio of phenyltrimethoxysilane, sodium hydroxide, deionized water and tetrahydrofuran in step B1 is 46 mmol: 50 mL: 58 mmol: 20 mmol, and the mass ratio of trisodium heptaphenylsiloxane, triethylamine and trichlorosilane is 2: 0.55: 0.3.

[0012] Furthermore, in step B2, the molar ratio of heptaphenyl cage-like silsesquioxane and acrolein diethanol condensate is 1:1, the amount of caster catalyst is 0.1% of the mass of acrolein diethanol condensate, the ratio of pretreated cage-like silsesquioxane, tetrahydrofuran and p-toluenesulfonic acid aqueous solution is 1g:10mL:0.12mL, and the mass ratio of p-toluenesulfonic acid aqueous solution is 5%.

[0013] The beneficial effects of this invention: The high flame-retardant PA66 composite material prepared by this invention includes the following raw materials: PA66 masterbatch, flame-retardant additive, maleic anhydride-grafted polyolefin elastomer, and montmorillonite. The flame-retardant additive is prepared by ring-opening condensation of octamethylcyclotetrasiloxane and tetramethyltetravinylcyclotetrasiloxane as raw materials, followed by end capping with 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane to form a polysiloxane with double bonds at both ends of amino side chains, thus obtaining a functionalized polysiloxane. The functionalized polysiloxane is reacted with DOPO, causing the double bonds of the functionalized polysiloxane to react with the PH bonds on DOPO, thus obtaining a pretreated polysiloxane. The pretreated polysiloxane is reacted with modified cage-like silsesquioxane, causing one amino group on the pretreated polysiloxane to react with the modified cage-like silsesquioxane and aldehyde group to form a carbon-nitrogen double bond. DOPO is then added to react with the carbon-nitrogen double bond to obtain the flame-retardant additive.

[0014] Modified cage-like silsesquioxanes are prepared by hydrolysis and condensation of phenyltrimethoxysilane to obtain trisodium heptaphenylsiloxane. The trisodium heptaphenylsiloxane is then reacted with trichlorosilane to obtain heptaphenyl cage-like silsesquioxane. The heptaphenyl cage-like silsesquioxane is then reacted with acrolein diethanol condensate, causing the double bond on the acrolein diethanol condensate to react with the Si-H bond on the heptaphenyl cage-like silsesquioxane to obtain a pretreated cage-like silsesquioxane. The pretreated cage-like silsesquioxane is then hydrolyzed with p-toluenesulfonic acid aqueous solution to form an aldehyde group, thus obtaining modified cage-like silsesquioxanes.

[0015] The flame retardant additive contains an active amino group. During melt blending, this amino group can undergo an amidation reaction with the terminal carboxyl group of the PA66 molecular chain, firmly anchoring the entire large flame retardant molecule to the PA66 matrix in the form of chemical bonds. This prevents flame retardant migration, achieves permanent flame retardancy, and extends the service life of the material. The DOPO group decomposes to release PO· free radicals, which efficiently capture H· and OH· in the combustion chain reaction. When the POSS cage burns, it collapses to form a dense nanoscale silica protective layer, promoting the char-forming condensed phase. The polysiloxane segments can provide a silicon source, enhancing the flexibility and thickness of the char layer and synergistically forming char. Montmorillonite forms a micron-scale lamellar char skeleton, which improves the density of the char and makes it more stable. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0017] Example 1: A method for preparing a high flame-retardant PA66 composite material, specifically including the following steps: PA66 masterbatch, flame retardant additives, maleic anhydride-grafted polyolefin elastomer, and montmorillonite were added to a twin-screw extruder and melt-extruded under the following conditions: feeding section temperature 240℃, compression section temperature 260℃, metering section temperature 270℃, and die head temperature 265℃, to obtain a high flame retardant PA66 composite material.

[0018] The weight ratio of PA66 masterbatch, flame retardant additive, maleic anhydride-grafted polyolefin elastomer and montmorillonite is 100:10:10:1, and the maleic anhydride-grafted polyolefin elastomer is Fusabond N493.

[0019] The flame retardant additive is prepared by the following steps: Step A1: Octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were mixed and purged with nitrogen. The mixture was reacted for 3 hours at a speed of 150 r / min and a temperature of 90 °C. The temperature was then raised to 140 °C and reacted for 1 hour to obtain functionalized polysiloxane. Step A2: Mix functionalized polysiloxane, DOPO and toluene evenly, purge with nitrogen for protection, stir and add azobisisobutyronitrile at a speed of 200 r / min and a temperature of 80℃, and react for 12 h to obtain pretreated polysiloxane. Step A3: Mix the modified cage-type silsesquioxane and tetrahydrofuran, stir and add pretreated polysiloxane at a speed of 300 r / min and a temperature of 20°C, raise the temperature to 45°C, add triethylamine, react for 6 h, add DOPO, raise the temperature to 60°C, and continue to react for 4 h to obtain the flame retardant additive.

[0020] The molar ratio of octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane in step A1 is 10:1:0.02:1.

[0021] The molar ratio of the double bond, DOPO and azobisisobutyronitrile on the functionalized polysiloxane described in step A2 is 2:2.1:0.04.

[0022] The molar ratio of the modified cage-like silsesquioxane, pretreated polysiloxane, and DOPO in step A3 is 1:1:1.1, and the amount of triethylamine used is 0.5% of the mass of the modified cage-like silsesquioxane and the pretreated polysiloxane.

[0023] The modified cage-like silsesquioxane is prepared by the following steps: Step B1: Phenylacetyltrimethoxysilane, sodium hydroxide, deionized water and tetrahydrofuran were mixed and reacted at 120 r / min and 70 °C for 5 h. The temperature was then lowered to 20 °C and reacted for 10 h to obtain trisodium heptaphenylsiloxane. Trisodium heptaphenylsiloxane, triethylamine and tetrahydrofuran were mixed and stirred at 150 r / min and 0 °C. Trichlorosilane was added and reacted for 3 h. The temperature was then raised to 20 °C and reacted for 20 h to obtain heptaphenylcage-type silsesquioxane. Step B2: Heptaphenyl cage-like silsesquioxane, acrolein diethanol, caster catalyst, and tetrahydrofuran were mixed and purged with nitrogen. The mixture was reacted for 6 hours at a speed of 200 r / min and a temperature of 80 °C to obtain pretreated cage-like silsesquioxane. The pretreated cage-like silsesquioxane was dissolved in tetrahydrofuran and stirred at a speed of 150 r / min and a temperature of 20 °C. An aqueous solution of p-toluenesulfonic acid was added and the mixture was reacted for 2 hours. Sodium bicarbonate was then added to neutralize the mixture to obtain modified cage-like silsesquioxane.

[0024] The ratio of phenyltrimethoxysilane, sodium hydroxide, deionized water and tetrahydrofuran used in step B1 is 46 mmol: 50 mL: 58 mmol: 20 mmol, and the mass ratio of trisodium heptaphenylsiloxane, triethylamine and trichlorosilane is 2: 0.55: 0.3.

[0025] In step B2, the molar ratio of heptaphenyl cage-like silsesquioxane and acrolein diethanol condensate is 1:1, the amount of caster catalyst is 0.1% of the mass of acrolein diethanol condensate, the ratio of pretreated cage-like silsesquioxane, tetrahydrofuran and p-toluenesulfonic acid aqueous solution is 1g:10mL:0.12mL, and the mass ratio of p-toluenesulfonic acid aqueous solution is 5%.

[0026] Example 2, a method for preparing a high flame-retardant PA66 composite material, specifically includes the following steps: PA66 masterbatch, flame retardant additives, maleic anhydride-grafted polyolefin elastomer, and montmorillonite were added to a twin-screw extruder and melt-extruded under the following conditions: feeding section temperature 245℃, compression section temperature 265℃, metering section temperature 275℃, and die head temperature 270℃, to obtain a high flame retardant PA66 composite material.

[0027] The weight ratio of PA66 masterbatch, flame retardant additive, maleic anhydride-grafted polyolefin elastomer and montmorillonite is 110:13:11:1.5, and the maleic anhydride-grafted polyolefin elastomer is FusabondN493.

[0028] The flame retardant additive is prepared by the following steps: Step A1: Octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were mixed and purged with nitrogen. The mixture was reacted at 150 r / min and 90 °C for 4 h. The temperature was then raised to 145 °C and reacted for 1.3 h to obtain functionalized polysiloxane. Step A2: Mix functionalized polysiloxane, DOPO and toluene evenly, purge with nitrogen for protection, stir and add azobisisobutyronitrile at a speed of 200 r / min and a temperature of 85°C, and react for 15 h to obtain pretreated polysiloxane. Step A3: Mix the modified cage-type silsesquioxane and tetrahydrofuran, stir and add pretreated polysiloxane at a speed of 300 r / min and a temperature of 25°C, heat to 50°C, add triethylamine, react for 7 h, add DOPO, heat to 65°C, and continue to react for 5 h to obtain the flame retardant additive.

[0029] The molar ratio of octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane in step A1 is 10:1:0.02:1.

[0030] The molar ratio of the double bond, DOPO and azobisisobutyronitrile on the functionalized polysiloxane described in step A2 is 2:2.1:0.04.

[0031] The molar ratio of the modified cage-like silsesquioxane, pretreated polysiloxane, and DOPO in step A3 is 1:1:1.1, and the amount of triethylamine used is 0.5% of the mass of the modified cage-like silsesquioxane and the pretreated polysiloxane.

[0032] The modified cage-like silsesquioxane is prepared by the following steps: Step B1: Phenylacetyltrimethoxysilane, sodium hydroxide, deionized water and tetrahydrofuran were mixed and reacted at 120 r / min and 75 °C for 6 h. The temperature was then lowered to 25 °C and reacted for 10 h to obtain trisodium heptaphenylsiloxane. Trisodium heptaphenylsiloxane, triethylamine and tetrahydrofuran were mixed and stirred at 200 r / min and 0 °C. Trichlorosilane was added and reacted for 4 h. The temperature was then raised to 25 °C and reacted for 20 h to obtain heptaphenylcage-type silsesquioxane. Step B2: Mix heptaphenyl cage-like silsesquioxane, acrolein diethanol, caster catalyst, and tetrahydrofuran, and purge with nitrogen. React at 300 r / min and 83 °C for 7 h to obtain pretreated cage-like silsesquioxane. Dissolve the pretreated cage-like silsesquioxane in tetrahydrofuran, and stir at 150-200 r / min and 25 °C while adding p-toluenesulfonic acid aqueous solution. React for 3 h, and then add sodium bicarbonate to neutralize, to obtain modified cage-like silsesquioxane.

[0033] The ratio of phenyltrimethoxysilane, sodium hydroxide, deionized water and tetrahydrofuran used in step B1 is 46 mmol: 50 mL: 58 mmol: 20 mmol, and the mass ratio of trisodium heptaphenylsiloxane, triethylamine and trichlorosilane is 2: 0.55: 0.3.

[0034] In step B2, the molar ratio of heptaphenyl cage-like silsesquioxane and acrolein diethanol condensate is 1:1, the amount of caster catalyst is 0.1% of the mass of acrolein diethanol condensate, the ratio of pretreated cage-like silsesquioxane, tetrahydrofuran and p-toluenesulfonic acid aqueous solution is 1g:10mL:0.12mL, and the mass ratio of p-toluenesulfonic acid aqueous solution is 5%.

[0035] Example 3: A method for preparing a high flame-retardant PA66 composite material, specifically including the following steps: PA66 masterbatch, flame retardant additives, maleic anhydride-grafted polyolefin elastomer, and montmorillonite were added to a twin-screw extruder and melt-extruded under the following conditions: feeding section temperature 250℃, compression section temperature 270℃, metering section temperature 280℃, and die head temperature 275℃, to obtain a high flame retardant PA66 composite material.

[0036] The weight ratio of PA66 masterbatch, flame retardant additive, maleic anhydride-grafted polyolefin elastomer and montmorillonite is 120:15:12:2, and the maleic anhydride-grafted polyolefin elastomer is FusabondN493.

[0037] The flame retardant additive is prepared by the following steps: Step A1: Octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were mixed and purged with nitrogen. The mixture was reacted for 5 hours at a rotation speed of 200 r / min and a temperature of 95 °C. The temperature was then raised to 145 °C and reacted for 1.5 hours to obtain functionalized polysiloxane. Step A2: Mix functionalized polysiloxane, DOPO and toluene evenly, purge with nitrogen for protection, stir and add azobisisobutyronitrile at a speed of 300 r / min and a temperature of 90℃, and react for 15 h to obtain pretreated polysiloxane. Step A3: Mix the modified cage-type silsesquioxane and tetrahydrofuran, stir and add pretreated polysiloxane at a speed of 500 r / min and a temperature of 25°C, raise the temperature to 55°C, add triethylamine, react for 8 h, add DOPO, raise the temperature to 70°C, and continue to react for 6 h to obtain the flame retardant additive.

[0038] The molar ratio of octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane in step A1 is 10:1:0.02:1.

[0039] The molar ratio of the double bond, DOPO and azobisisobutyronitrile on the functionalized polysiloxane described in step A2 is 2:2.1:0.04.

[0040] The molar ratio of the modified cage-like silsesquioxane, pretreated polysiloxane, and DOPO in step A3 is 1:1:1.1, and the amount of triethylamine used is 0.5% of the mass of the modified cage-like silsesquioxane and the pretreated polysiloxane.

[0041] The modified cage-like silsesquioxane is prepared by the following steps: Step B1: Phenylacetyltrimethoxysilane, sodium hydroxide, deionized water and tetrahydrofuran were mixed and reacted at 150 r / min and 75°C for 7 h. The mixture was then cooled to 25°C and reacted for 15 h to obtain trisodium heptaphenylsiloxane. Trisodium heptaphenylsiloxane, triethylamine and tetrahydrofuran were mixed and stirred at 200 r / min and 0°C. Trichlorosilane was added and the mixture was reacted for 5 h. The mixture was then heated to 25°C and reacted for 25 h to obtain heptaphenylcage-type silsesquioxane. Step B2: Heptaphenyl cage-like silsesquioxane, acrolein diethanol condensate, caster catalyst, and tetrahydrofuran were mixed and purged with nitrogen. The mixture was reacted for 8 hours at a speed of 300 r / min and a temperature of 85 °C to obtain pretreated cage-like silsesquioxane. The pretreated cage-like silsesquioxane was dissolved in tetrahydrofuran and stirred at a speed of 200 r / min and a temperature of 25 °C. An aqueous solution of p-toluenesulfonic acid was added and the mixture was reacted for 4 hours. Sodium bicarbonate was then added to neutralize the mixture to obtain modified cage-like silsesquioxane.

[0042] The ratio of phenyltrimethoxysilane, sodium hydroxide, deionized water and tetrahydrofuran used in step B1 is 46 mmol: 50 mL: 58 mmol: 20 mmol, and the mass ratio of trisodium heptaphenylsiloxane, triethylamine and trichlorosilane is 2: 0.55: 0.3.

[0043] In step B2, the molar ratio of heptaphenyl cage-like silsesquioxane and acrolein diethanol condensate is 1:1, the amount of caster catalyst is 0.1% of the mass of acrolein diethanol condensate, the ratio of pretreated cage-like silsesquioxane, tetrahydrofuran and p-toluenesulfonic acid aqueous solution is 1g:10mL:0.12mL, and the mass ratio of p-toluenesulfonic acid aqueous solution is 5%.

[0044] Comparative Example 1: In this comparative example, benzaldehyde is replaced with modified cage-like silsesquioxane instead of Example 1, and the remaining steps are the same.

[0045] Comparative Example 2: Compared with Example 1, the molar ratio of the modified cage-like silsesquioxane, pretreated polysiloxane and DOPO in step A3 is 2:1:2.1, and the other steps are the same.

[0046] Comparative Example 3: This comparative example uses ethylenediamine instead of pretreated polysiloxane compared to Example 1, with the remaining steps being the same.

[0047] The PA66 composite materials obtained in Examples 1-3 and Comparative Examples 1-3 were prepared into 125mm×13mm×3.2mm samples according to the standard of GB / T2408-2021, and the vertical flammability was tested. The samples were prepared into 120mm×10mm×4mm samples according to the standard of GB / T2406.2-2009, and the limiting oxygen index was tested. The samples were placed in water at 80℃ and soaked for 7 days. The vertical flammability and limiting oxygen index were tested. The test results are shown in Table 1 below.

[0048] Table 1 As shown in Table 1, this application has excellent flame retardant effect and avoids flame retardant migration. The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a high flame-retardant PA66 composite material, characterized in that: Specifically, the steps include the following: PA66 masterbatch, flame retardant additives, maleic anhydride-grafted polyolefin elastomer, and montmorillonite were added to a twin-screw extruder and melt-extruded to obtain a high flame retardant PA66 composite material.

2. The method for preparing the high flame-retardant PA66 composite material according to claim 1, characterized in that: The weight ratio of PA66 masterbatch, flame retardant additive, maleic anhydride grafted polyolefin elastomer and montmorillonite is 100-120:10-15:10-12:1-2.

3. The method for preparing the high flame-retardant PA66 composite material according to claim 1, characterized in that: The flame retardant additive is prepared by the following steps: Step A1: Mix octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, purge with nitrogen, and react to obtain functionalized polysiloxane. Step A2: Mix functionalized polysiloxane, DOPO and toluene evenly, purge with nitrogen for protection, stir and add azobisisobutyronitrile to carry out the reaction, and obtain pretreated polysiloxane. Step A3: Mix the modified cage-type silsesquioxane and tetrahydrofuran, stir and add the pretreated polysiloxane, heat and add triethylamine, react, add DOPO, heat and react to obtain the flame retardant additive.

4. The method for preparing the high flame-retardant PA66 composite material according to claim 3, characterized in that: The molar ratio of octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane in step A1 is 10:1:0.02:

1.

5. The method for preparing the high flame-retardant PA66 composite material according to claim 3, characterized in that: The molar ratio of the double bond, DOPO and azobisisobutyronitrile on the functionalized polysiloxane described in step A2 is 2:2.1:0.

04.

6. The method for preparing the high flame-retardant PA66 composite material according to claim 3, characterized in that: The molar ratio of the modified cage-like silsesquioxane, pretreated polysiloxane, and DOPO mentioned in step A3 is 1:1:1.

1.

7. The method for preparing the high flame-retardant PA66 composite material according to claim 3, characterized in that: The modified cage-like silsesquioxane is prepared by the following steps: Step B1: Mix phenyltrimethoxysilane, sodium hydroxide, deionized water and tetrahydrofuran and react to obtain trisodium heptaphenylsiloxane. Mix trisodium heptaphenylsiloxane, triethylamine and tetrahydrofuran and stir, then add trichlorosilane and react to obtain heptaphenyl cage-type silsesquioxane. Step B2: Mix heptaphenyl cage-like silsesquioxane, acrolein diethanol condensate, caster catalyst and tetrahydrofuran, purge with nitrogen for protection, and react to obtain pretreated cage-like silsesquioxane. Dissolve the pretreated cage-like silsesquioxane in tetrahydrofuran, stir and add p-toluenesulfonic acid aqueous solution, react, and then add sodium bicarbonate to neutralize, to obtain modified cage-like silsesquioxane.

8. The method for preparing the high flame-retardant PA66 composite material according to claim 7, characterized in that: The ratio of phenyltrimethoxysilane, sodium hydroxide, deionized water and tetrahydrofuran used in step B1 is 46 mmol: 50 mL: 58 mmol: 20 mmol, and the mass ratio of trisodium heptaphenylsiloxane, triethylamine and trichlorosilane is 2: 0.55: 0.

3.

9. The method for preparing the high flame-retardant PA66 composite material according to claim 7, characterized in that: The molar ratio of heptaphenyl cage-like silsesquioxane and acrolein diethanol condensate in step B2 is 1:1, and the ratio of pretreated cage-like silsesquioxane, tetrahydrofuran, and p-toluenesulfonic acid aqueous solution is 1g:10mL:0.12mL.

10. A high flame-retardant PA66 composite material, characterized in that: Prepared according to any one of the preparation methods described in claims 1-9.

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