High-temperature-resistant flame-retardant nylon composite material and preparation method thereof

Abstract

The application discloses a kind of high-temperature-resistant flame-retardant nylon composite material and preparation method thereof, belong to high polymer material technical field.100-110 parts of nylon resin, 40-60 parts of flame retardant, 1-3 parts of lubricant, 0.5-2 parts of antioxidant and 0.5-2 parts of ultraviolet absorber are mixed uniformly, and double screw extruder is added by main feeding, then the flame retardant is added into double screw extruder by side feeding, after extrusion, drawing, cooling, granulating and drying, high-temperature-resistant flame-retardant nylon composite material is prepared.The flame retardant contains high dispersity magnesium hydroxide and halogen-free flame-retardant elements nitrogen, phosphorus and silicon, and does not contain any halogen, so that the flame retardant has high flame-retardant, low smoke generation, low harmful flame-retardant effect, which can effectively broaden the application field of nylon composite material.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically, it relates to a high-temperature resistant flame-retardant nylon composite material and its preparation method. Background Technology

[0002] Polyamide (PA), commonly known as nylon, has received increasing attention since its invention. High-temperature resistant nylon possesses excellent properties and is widely used in the electronics, electrical, and automotive industries. While high-temperature resistant nylon exhibits excellent heat resistance, its flame-retardant properties fall short of practical application requirements, significantly limiting its use in many fields. Therefore, improving the flame-retardant properties of high-temperature resistant nylon is both urgent and necessary.

[0003] To give nylon materials good flame retardancy, halogenated flame retardants are usually added. Although the addition of halogenated flame retardants can achieve a flame retardant effect, they will produce a large amount of toxic smoke when burning. In fact, it has been proven that the cause of death in fire accidents is not the fire itself, but the suffocation of trapped people caused by toxic smoke.

[0004] Therefore, there is an urgent need to develop a high-temperature nylon composite material with efficient and safe flame-retardant properties to broaden the application fields of the material and meet market demands. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-temperature resistant flame-retardant nylon composite material and its preparation method.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A high-temperature resistant flame-retardant nylon composite material comprises the following raw materials in parts by weight: 100-110 parts nylon resin, 40-60 parts flame retardant, 1-3 parts lubricant, 0.5-2 parts antioxidant, and 0.5-2 parts ultraviolet absorber.

[0008] Furthermore, the nylon resin is one or more of PA46, PA9T, and PA10T.

[0009] Furthermore, the flame retardant is prepared by the following steps:

[0010] S1. Under nitrogen protection, 3-[(hydroxymethyl)amino]-3-oxopropylphosphonic acid-dimethyl ester, maleic anhydride, DMAP (4-dimethylaminopyridine), and chloroform were added to a three-necked flask. The mixture was stirred thoroughly until homogeneous, then heated to 50°C and kept at that temperature for 12 hours. After the reaction was completed, the mixture was cooled to room temperature, distilled under reduced pressure, washed three times with saturated brine, then three times with anhydrous ethanol, and finally dried at 80°C for 12 hours to obtain intermediate 1. The ratio of 3-[(hydroxymethyl)amino]-3-oxopropylphosphonic acid-dimethyl ester, maleic anhydride, DMAP, and chloroform was 17.5 mL: 11 g: 0.7 g: 200 mL.

[0011] Under the catalysis of DMAP, by controlling the molar ratio of 3-[(hydroxymethyl)amino]-3-oxopropylphosphonic acid-dimethyl ester and maleic anhydride to 1:1.05-1.1, the hydroxyl group of 3-[(hydroxymethyl)amino]-3-oxopropylphosphonic acid-dimethyl ester can undergo esterification reaction with maleic anhydride.

[0012] S2. Under nitrogen protection, intermediate 1, EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride), NHS (N-hydroxysuccinimide), and dimethyl sulfoxide were added to a three-necked flask. After stirring and dissolving, melamine was slowly added, and the mixture was stirred and heated to 65°C. The reaction was maintained at this temperature for 6.5 h. After the reaction was completed, the mixture was cooled to room temperature, purified by vacuum distillation, and column chromatography (using a mixed solvent of chloroform and diethyl ether as the eluent, with a volume ratio of 9:1). Vacuum distillation was then performed to obtain intermediate 2. The ratio of intermediate 1, melamine, EDC, NHS, and dimethyl sulfoxide was 29.5 g: 3.8 g: 0.3 g: 0.2 g: 250 mL.

[0013] Under the influence of EDC and NHS, if the molar ratio of intermediate 1 to melamine is controlled to be 3.1-3.2:1, then the -COOH of intermediate 1 will undergo an amidation reaction with the -NH2 of melamine.

[0014] S3. Purge the dry three-necked flask with nitrogen for 30 minutes to remove air and moisture. Then add intermediates 2,3-mercaptopropyltriethoxysilane, 2-tert-butylanthraquinone, and dimethyl sulfoxide. Mix well and stir to dissolve. Irradiate under a 365 nm UV lamp for 0.5 h under nitrogen protection. After irradiation, distill under reduced pressure to obtain intermediate 3. The ratio of intermediates 2,3-mercaptopropyltriethoxysilane, 2-tert-butylanthraquinone, and dimethyl sulfoxide is 20 g: 14.9 mL: 0.5 g: 200 mL.

[0015] Under ultraviolet light irradiation and the action of the photoinitiator 2-tert-butylanthraquinone, if the molar ratio of intermediate 2 and 3-mercaptopropyltriethoxysilane is controlled to be 1:3.05-3.1, intermediate 2 and 3-mercaptopropyltriethoxysilane will undergo a mercapto-alkene click reaction.

[0016] S4. Add magnesium hydroxide, anhydrous ethanol, and deionized water to a three-necked flask, stir well, and then add acetic acid to adjust the pH to 4. Under nitrogen protection, disperse intermediate 3 in DMF (N,N-dimethylformamide), stir to dissolve, and then transfer to the above three-necked flask. After the transfer is complete, stir and heat to 65°C, and keep the temperature for 1 hour. After the reaction is complete, cool to room temperature, centrifuge, take the precipitate, and ultrasonically disperse it in DMF. Finally, dry at 110°C for 12 hours to obtain the flame retardant. The ratio of magnesium hydroxide to intermediate 3 is 30g:10g.

[0017] After hydrolysis, intermediate 3 generates silanol groups that react with the hydroxyl groups on the surface of magnesium hydroxide to form stable chemical bonds. The formation of these new bonds lowers the surface energy of magnesium hydroxide, stabilizing it. Simultaneously, the organic medium on the surface of the magnesium hydroxide particles increases the spatial resistance to particle aggregation, improving its dispersibility. This allows magnesium hydroxide to fully exert its flame-retardant and smoke-suppressing effects, significantly enhancing the flame-retardant performance of nylon composites. The flame retardant also contains abundant halogen-free flame-retardant elements nitrogen, phosphorus, and silicon. Phosphorus provides an acid source, reacting with the polymer resin to promote char formation; nitrogen provides a gas source, enabling the system to expand and foam, further promoting the formation of the char layer and creating porous foamed char; silicon, during combustion, generates an inorganic thermal insulation protective layer containing -Si-O and -Si-C bonds, preventing the escape of combustion decomposition products and inhibiting the thermal decomposition of polymer materials, achieving high flame retardancy, low smoke emission, and low toxicity. The flame retardant, through the synergistic flame retardancy of organic and inorganic components, endows the high-temperature resistant nylon material of this invention with excellent flame retardant properties, and the flame retardant effect is more efficient and safer.

[0018] Furthermore, the lubricant is one or more of calcium stearate, magnesium stearate, zinc stearate, and stearic acid.

[0019] Furthermore, the antioxidant is one or more of antioxidant 1098, antioxidant 1010, antioxidant 1790, antioxidant 1035, and antioxidant 168.

[0020] Furthermore, the ultraviolet absorber is one or more of ultraviolet absorber UV-571, ultraviolet absorber UV-P, ultraviolet absorber UV-531, and ultraviolet absorber UV-9.

[0021] A method for preparing a high-temperature resistant flame-retardant nylon composite material includes the following steps:

[0022] Weigh each raw material according to weight, mix the nylon resin, flame retardant, lubricant, antioxidant and ultraviolet absorber evenly, feed them into the twin-screw extruder through the main feed, and then feed the flame retardant into the twin-screw extruder through the side feed. After extrusion, stranding, cooling, pelleting and drying, a high-temperature resistant flame-retardant nylon composite material is obtained.

[0023] The beneficial effects of the present invention are as follows: The flame retardant of the present invention contains highly dispersed magnesium hydroxide and halogen-free flame retardant elements nitrogen, phosphorus and silicon, and does not contain any halogens. Therefore, the flame retardant of the present invention has the flame retardant effect of high flame retardancy, low smoke emission and low toxicity, which can effectively broaden the application field of nylon composite materials. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1: Preparation of flame retardant, the specific steps are as follows:

[0026] S1. Under nitrogen protection, 17.5 mL of 3-[(hydroxymethyl)amino]-3-oxopropylphosphonic acid-dimethyl ester, 11 g of maleic anhydride, 0.7 g of DMAP, and 200 mL of chloroform were added to a 500 mL three-necked flask. The mixture was stirred thoroughly until homogeneous, and then heated to 50 °C and kept at that temperature for 12 h. After the reaction was completed, the mixture was cooled to room temperature, distilled under reduced pressure, washed three times with saturated brine, then washed three times with anhydrous ethanol, and finally dried at 80 °C for 12 h to obtain intermediate 1.

[0027] S2. Under nitrogen protection, 29.5 g of intermediate 1, 0.3 g of EDC, 0.2 g of NHS and 250 mL of dimethyl sulfoxide were added to a 500 mL three-necked flask. After stirring and dissolving, 3.8 g of melamine was slowly added, and the mixture was stirred and heated to 65 °C. The reaction was maintained at this temperature for 6.5 h. After the reaction was completed, the mixture was cooled to room temperature, purified by vacuum distillation and column chromatography (the eluent was a mixture of chloroform and diethyl ether, with a volume ratio of 9:1). The mixture was then distilled under reduced pressure to obtain intermediate 2.

[0028] S3. Purge a 500mL dry three-necked flask with nitrogen for 30 minutes to remove air and moisture. Then add 20g of intermediate 2, 14.9mL of 3-mercaptopropyltriethoxysilane, 0.5g of 2-tert-butylanthraquinone, and 200mL of dimethyl sulfoxide. Mix well and stir to dissolve. Irradiate under a 365nm UV lamp for 0.5h under nitrogen protection. After irradiation, distill under reduced pressure to obtain intermediate 3.

[0029] S4. Add 30g magnesium hydroxide, 150mL anhydrous ethanol and 100mL deionized water to a 500mL three-necked flask, stir well, and then add acetic acid to adjust the pH to 4. Under nitrogen protection, disperse 10g intermediate 3 in 50mL DMF, stir to dissolve, and then transfer to the above three-necked flask. After the transfer is complete, stir and heat to 65℃, keep the temperature for 1h, cool to room temperature after the reaction is completed, centrifuge, take the precipitate and ultrasonically disperse it in DMF, and finally dry at 110℃ for 12h to obtain the flame retardant.

[0030] Example 2: Preparation of nylon composite material, the specific steps are as follows:

[0031] Weigh each raw material according to the weight parts, and mix 100 parts of PA46, 40 parts of the flame retardant prepared in Example 1, 1 part of calcium stearate, 0.5 parts of antioxidant 1098 and 0.5 parts of ultraviolet absorber UV-571 evenly. Add the mixture to the twin-screw extruder by the main feed, and then add the flame retardant to the twin-screw extruder by the side feed. After extrusion, stranding, cooling, pelleting and drying, nylon composite material is obtained.

[0032] Example 3: Preparation of nylon composite material, the specific steps are as follows:

[0033] Weigh each raw material according to weight, and mix 105 parts PA9T, 50 parts flame retardant prepared in Example 1, 1 part magnesium stearate, 1 part stearic acid, 1 part antioxidant 1010, 0.5 parts antioxidant 168, 0.5 parts ultraviolet absorber UV-P, and 0.5 parts ultraviolet absorber UV-9 evenly. Add the mixture to the twin-screw extruder through the main feed, and then add the flame retardant to the twin-screw extruder through the side feed. After extrusion, stranding, cooling, pelletizing, and drying, nylon composite material is obtained.

[0034] Example 4: Preparation of nylon composite material, the specific steps are as follows:

[0035] Weigh out each raw material according to weight parts, and mix 110 parts PA10T, 60 parts flame retardant prepared in Example 1, 1 part calcium stearate, 1 part zinc stearate, 1 part stearic acid, 0.5 parts antioxidant 1098, 0.5 parts antioxidant 1790, 0.5 parts antioxidant 1035, 0.5 parts antioxidant 168, 1 part ultraviolet absorber UV-571, and 1 part ultraviolet absorber UV-531 evenly. Add the mixture to the twin-screw extruder through the main feed, and then add the flame retardant to the twin-screw extruder through the side feed. After extrusion, stranding, cooling, pelletizing, and drying, nylon composite material is obtained.

[0036] Comparative Example 1: Nylon composite material was prepared, and the specific steps are as follows:

[0037] The remaining steps remain the same, except that the flame retardant in Example 2 is replaced with untreated magnesium hydroxide to prepare the nylon composite material.

[0038] Comparative Example 2: Preparation of nylon composite material, the specific steps are as follows:

[0039] The remaining steps remain the same, except that the flame retardant in Example 2 is replaced with ammonium polyphosphate to prepare the nylon composite material.

[0040] Comparative Example 3: Nylon composite material was prepared, and the specific steps are as follows:

[0041] The remaining steps remain unchanged, except that the flame retardant in Example 2 is replaced with 30 parts of untreated magnesium hydroxide and 10 parts of ammonium polyphosphate to prepare the nylon composite material.

[0042] Performance testing

[0043] The high-temperature resistant nylon composite materials prepared in Examples 2-4 and Comparative Examples 1-3 were tested according to ISO 4589-2 for limiting oxygen index; UL-94 for vertical flammability rating; and ASTM D 648-07 for heat distortion temperature. The test results are shown in the table below:

[0044] Test Project Limiting oxygen index / % Vertical flammability rating Heat distortion temperature / ℃ Example 2 40.2 V-0 284.5 Example 3 40.7 V-0 285.0 Example 4 41.1 V-0 285.4 Comparative Example 1 31.9 V-2 279.9 Comparative Example 2 33.4 V-1 279.6 Comparative Example 3 33.8 V-1 280.2

[0045] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0046] The above description is merely an example and illustration 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 invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A high-temperature resistant and flame-retardant nylon composite material, characterized in that, The raw materials include the following parts by weight: 100-110 parts nylon resin, 40-60 parts flame retardant, 1-3 parts lubricant, 0.5-2 parts antioxidant, and 0.5-2 parts ultraviolet absorber; The flame retardant is prepared through the following steps: S1. Under nitrogen protection, 3-[(hydroxymethyl)amino]-3-oxopropylphosphonic acid-dimethyl ester, maleic anhydride, DMAP, and chloroform were added to a flask. The mixture was stirred and heated to 50°C for 12 hours. After cooling, the mixture was distilled under reduced pressure, washed with saturated brine, washed with anhydrous ethanol, and dried to obtain intermediate 1. The ratio of 3-[(hydroxymethyl)amino]-3-oxopropylphosphonic acid-dimethyl ester, maleic anhydride, DMAP, and chloroform was 17.5 mL: 11 g: 0.7 g: 200 mL. S2. Under nitrogen protection, intermediate 1, EDC, NHS and dimethyl sulfoxide were added to a flask, stirred, and then melamine was added. The mixture was heated to 65℃ and reacted for 6.5 h. After cooling, the mixture was purified by vacuum distillation, column chromatography, and vacuum distillation to obtain intermediate 2. The ratio of intermediate 1, melamine, EDC, NHS and dimethyl sulfoxide was 29.5 g: 3.8 g: 0.3 g: 0.2 g: 250 mL. S3. After purging the flask with nitrogen, add intermediates 2,3-mercaptopropyltriethoxysilane, 2-tert-butylanthraquinone and dimethyl sulfoxide, mix, and irradiate under a 365 nm UV lamp for 0.5 h under nitrogen protection. Distill under reduced pressure to obtain intermediate 3. The ratio of intermediates 2,3-mercaptopropyltriethoxysilane, 2-tert-butylanthraquinone and dimethyl sulfoxide is 20 g: 14.9 mL: 0.5 g: 200 mL. S4. Add magnesium hydroxide, anhydrous ethanol and deionized water to a flask, stir, and adjust the pH to 4 with acetic acid; disperse intermediate 3 in DMF and transfer it to the above flask, stir and heat to 65℃ for 1 hour, cool, centrifuge, take the precipitate and ultrasonically disperse it in DMF, dry it to obtain the flame retardant; the ratio of magnesium hydroxide to intermediate 3 is 30g:10g.

2. The high-temperature resistant and flame-retardant nylon composite material according to claim 1, characterized in that, The nylon resin is one or more of PA46, PA9T, and PA10T.

3. The high-temperature resistant flame-retardant nylon composite material according to claim 1, characterized in that, The lubricant is one or more of calcium stearate, magnesium stearate, zinc stearate, and stearic acid.

4. The high-temperature resistant and flame-retardant nylon composite material according to claim 1, characterized in that, The antioxidant is one or more of antioxidant 1098, antioxidant 1010, antioxidant 1790, antioxidant 1035, and antioxidant 168.

5. The high-temperature resistant and flame-retardant nylon composite material according to claim 1, characterized in that, The ultraviolet absorber is one or more of ultraviolet absorber UV-571, ultraviolet absorber UV-P, ultraviolet absorber UV-531, and ultraviolet absorber UV-9.

6. The method for preparing a high-temperature resistant flame-retardant nylon composite material according to claim 1, characterized in that, Includes the following steps: Weigh each raw material according to weight, mix the nylon resin, flame retardant, lubricant, antioxidant and ultraviolet absorber evenly, feed them into the twin-screw extruder through the main feed, and then feed the flame retardant into the twin-screw extruder through the side feed. After extrusion, stranding, cooling, pelleting and drying, a high-temperature resistant flame-retardant nylon composite material is obtained.