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

Abstract

The invention discloses a high-temperature-resistant flame-retardant nylon composite material and a preparation method thereof, and belongs to the technical field of high polymer materials. The preparation method comprises the following steps: uniformly mixing 100-110 parts of nylon resin, 40-60 parts of a flame retardant, 1-3 parts of a lubricant, 0.5-2 parts of an antioxidant and 0.5-2 parts of an ultraviolet light absorber, adding the mixture into a double-screw extruder from a main feed, adding the flame retardant into the double-screw extruder from a side feed, and performing extrusion, bracing, cooling, pelletizing and drying to obtain the high-temperature-resistant flame-retardant nylon composite material. The flame retardant disclosed by the invention contains high-dispersity magnesium hydroxide and halogen-free flame-retardant elements, namely nitrogen, phosphorus and silicon, and does not contain any halogen, so that the flame retardant disclosed by the invention has the flame-retardant effects of high flame retardance, low smoke generation amount and low harmfulness, and the application field of a nylon composite material can be effectively widened.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and in particular relates to a high-temperature resistant and flame-retardant nylon composite material and a preparation method thereof. Background Art

[0002] Polyamide (PA), commonly known as nylon, has garnered increasing attention since its introduction. High-temperature resistant nylon boasts excellent performance and is widely used in the electrical and electronic, electronics, and automotive industries. While high-temperature resistant nylon exhibits excellent heat resistance, its flame retardancy falls far short of actual application requirements, significantly limiting its application in many fields. Therefore, improving the flame retardancy of high-temperature resistant nylon is both urgent and necessary.

[0003] In order to make nylon materials have good flame retardancy, halogen-containing flame retardants are usually added. Although the addition of halogen-containing flame retardants can have a flame retardant effect, it will produce a large amount of toxic smoke when burning. Facts have proved that it is not the fire itself that causes a large number of deaths in fire accidents, but the toxic smoke that causes the trapped people to suffocate to death.

[0004] Therefore, there is an urgent need to prepare a high-temperature resistant nylon composite material with efficient and safe flame retardant effect to broaden the application field of the material and meet market demand. Summary of the Invention

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

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A high-temperature resistant and flame-retardant nylon composite material comprises the following raw materials in parts by weight: 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.

[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- oxopropyl phosphonic acid - dimethyl ester, maleic anhydride, DMAP (4-dimethylaminopyridine) and chloroform were added to a three-necked flask, stirred until mixed, and then stirred and heated to 50 ° C., and the reaction was kept warm for 12 hours. After the reaction was completed, it was cooled to room temperature, and after reduced pressure distillation, it was first washed with saturated brine 3 times, then washed with anhydrous ethanol 3 times, and finally dried at 80 ° C. for 12 hours to obtain intermediate 1; the amount ratio of 3-[(hydroxymethyl) amino] -3- oxopropyl phosphonic acid - dimethyl ester, maleic anhydride, DMAP and chloroform was 17.5mL:11g:0.7g:200mL;

[0011] Under the catalytic action of DMAP, the molar ratio of 3-[(hydroxymethyl)amino]-3-oxopropylphosphonic acid-dimethyl ester and maleic anhydride is controlled to be 1:1.05-1.1, and 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, and melamine was slowly added after stirring to dissolve. The mixture was heated to 65° C. with stirring and the reaction was kept for 6.5 hours. After the reaction was completed, it was first cooled to room temperature and distilled under reduced pressure. The mixture was purified by column chromatography (a mixed solvent of chloroform and diethyl ether was selected as the eluent, and the volume ratio of chloroform and diethyl ether was 9:1). The mixture was distilled under reduced pressure to obtain intermediate 2; the amount 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 action of EDC and NHS, the molar ratio of intermediate 1 to melamine is controlled to be 3.1-3.2:1, and the -COOH of intermediate 1 undergoes an amidation reaction with the -NH2 of melamine.

[0014] S3, the dry three-necked flask was purged with nitrogen for 30 min to expel the air and moisture in the bottle, and then the intermediate 2, 3-mercaptopropyltriethoxysilane, 2-tert-butylanthraquinone and dimethyl sulfoxide were added, mixed and stirred to dissolve, and then placed under a 365nm ultraviolet lamp under nitrogen protection for 0.5 h. After the irradiation, it was distilled under reduced pressure to obtain intermediate 3; the amount ratio of intermediate 2, 3-mercaptopropyltriethoxysilane, 2-tert-butylanthraquinone and dimethyl sulfoxide was 20 g:14.9 mL:0.5 g:200 mL;

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

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

[0017] The silanol groups generated by hydrolysis of intermediate 3 react with the hydroxyl groups on the surface of magnesium hydroxide to form stable chemical bonds. The formation of these new bonds reduces the surface energy of the magnesium hydroxide, stabilizing it. Simultaneously, the organic medium on the surface of the magnesium hydroxide particles increases the spatial resistance between the magnesium hydroxide particles, thereby improving the dispersion of the magnesium hydroxide. This allows the magnesium hydroxide to fully exert its flame retardant and smoke suppression properties, significantly enhancing the flame retardancy of the nylon composite. 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 the formation of carbonized products. Nitrogen provides a gas source, causing the system to expand and foam, also promoting the formation of a carbonized layer, resulting in a porous foamed carbon. Silicon, during combustion, forms an inorganic thermally insulating protective layer containing -Si-O and -Si-C bonds. This prevents the escape of decomposition products and inhibits the thermal decomposition of the polymer, achieving high flame retardancy, low smoke emission, and low toxicity. The flame retardant provides the high-temperature resistant nylon material of the present invention with excellent flame retardant properties through the synergistic flame retardancy of the organic component and the inorganic component, and the flame retardant effect is more efficient and safe.

[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 comprises the following steps:

[0022] The raw materials are weighed according to weight, and the nylon resin, flame retardant, lubricant, antioxidant and ultraviolet absorber are mixed evenly, and then added into the twin-screw extruder through the main feed. The flame retardant is then added into the twin-screw extruder through the side feed. After extrusion, drawing, cooling, pelletizing and drying, a high-temperature resistant flame-retardant nylon composite material is obtained.

[0023] Beneficial effects of the present invention: The flame retardant of the present invention contains highly dispersible magnesium hydroxide and halogen-free flame retardant elements nitrogen, phosphorus, and silicon, and does not contain any halogen. Therefore, the flame retardant of the present invention has high flame retardancy, low smoke emission, and low harmfulness, and can effectively broaden the application field of nylon composite materials. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] Example 1, preparing a 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, and the mixture was thoroughly stirred until uniformly mixed. The mixture was then heated to 50° C. with stirring and kept for 12 h. After the reaction was completed, the mixture was cooled to room temperature, and the mixture was distilled under reduced pressure, washed with saturated brine three times, then washed with anhydrous ethanol three times, 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, and after stirring to dissolve, 3.8 g of melamine was slowly added. The mixture was stirred and heated to 65° C., and the reaction was kept warm for 6.5 h. After the reaction was completed, it was first cooled to room temperature and distilled under reduced pressure. The mixture was purified by column chromatography (a mixed solvent of chloroform and diethyl ether was selected as the eluent, and the volume ratio of chloroform and diethyl ether was 9:1), and distilled under reduced pressure to obtain intermediate 2;

[0028] S3, a 500 mL dry three-necked flask was purged with nitrogen for 30 min to expel air and moisture in the flask, and then 20 g of intermediate 2, 14.9 mL of 3-mercaptopropyltriethoxysilane, 0.5 g of 2-tert-butylanthraquinone and 200 mL of dimethyl sulfoxide were added, mixed and stirred to dissolve, and then placed under a 365 nm ultraviolet lamp under nitrogen protection for 0.5 h. After the irradiation, it was distilled under reduced pressure to obtain intermediate 3;

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

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

[0031] The raw materials were weighed by weight, and 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 were mixed uniformly. The mixture was added to a twin-screw extruder via the main feed, and the flame retardant was then added to the twin-screw extruder via the side feed. After extrusion, drawing, cooling, pelletizing, and drying, a nylon composite material was obtained.

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

[0033] The raw materials were weighed by weight, and 105 parts of PA9T, 50 parts of the flame retardant prepared in Example 1, 1 part of magnesium stearate, 1 part of stearic acid, 1 part of antioxidant 1010, 0.5 parts of antioxidant 168, 0.5 parts of ultraviolet absorber UV-P, and 0.5 parts of ultraviolet absorber UV-9 were mixed uniformly. The mixture was added to a twin-screw extruder via the main feed, and the flame retardant was then added to the twin-screw extruder via the side feed. After extrusion, stranding, cooling, pelletizing, and drying, a nylon composite material was obtained.

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

[0035] The raw materials were weighed by weight, and 110 parts of PA10T, 60 parts of the flame retardant prepared in Example 1, 1 part of calcium stearate, 1 part of zinc stearate, 1 part of stearic acid, 0.5 parts of antioxidant 1098, 0.5 parts of antioxidant 1790, 0.5 parts of antioxidant 1035, 0.5 parts of antioxidant 168, 1 part of ultraviolet absorber UV-571, and 1 part of ultraviolet absorber UV-531 were mixed uniformly, and then added to a twin-screw extruder through the main feed, and then the flame retardant was added to the twin-screw extruder through the side feed. After extrusion, drawing, cooling, pelletizing and drying, a nylon composite material was obtained.

[0036] Comparative Example 1: Preparation of a nylon composite material, the specific steps are as follows:

[0037] The remaining steps remained unchanged, except that the flame retardant in Example 2 was replaced by untreated magnesium hydroxide to prepare a nylon composite material.

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

[0039] The remaining steps remained unchanged, except that the flame retardant in Example 2 was replaced by ammonium polyphosphate to prepare a nylon composite material.

[0040] Comparative Example 3: Preparation of a nylon composite material, the specific steps are as follows:

[0041] The remaining steps remained unchanged, except that the flame retardant in Example 2 was replaced by 30 parts of untreated magnesium hydroxide and 10 parts of ammonium polyphosphate to prepare a 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 for limiting oxygen index according to ISO 4589-2, vertical burning rating according to UL-94, and heat deformation temperature according to ASTM D 648-07. The test results are shown in the following table:

[0044] Test items Limiting oxygen index / % Vertical combustion level Heat deformation 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] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these 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 any one or more embodiments or examples.

[0046] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A high temperature resistant flame retardant nylon composite material, characterized in that: The invention comprises the following raw materials in parts by weight: 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; Wherein, the flame retardant is prepared by 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, and the temperature was raised to 50° C. with stirring for 12 h. The mixture was cooled, evaporated under reduced pressure, washed with saturated brine, washed with anhydrous ethanol, and dried to obtain intermediate 1; the amount 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, and melamine was added after stirring. The temperature was raised to 65° C. and the reaction was carried out for 6.5 hours. The mixture was cooled, evaporated under reduced pressure, purified by column chromatography, and evaporated under reduced pressure to obtain intermediate 2. The amount 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 nitrogen was blown into the flask, intermediate 2, 3-mercaptopropyltriethoxysilane, 2-tert-butylanthraquinone and dimethyl sulfoxide were added, mixed, and irradiated under a 365nm ultraviolet lamp for 0.5h under nitrogen protection, and distilled under reduced pressure to obtain intermediate 3; the amount ratio of intermediate 2, 3-mercaptopropyltriethoxysilane, 2-tert-butylanthraquinone and dimethyl sulfoxide was 20g:14.9mL:0.5g:200mL; S4. Add magnesium hydroxide, anhydrous ethanol and deionized water to a flask, stir, and adjust the pH to 4 with acetic acid; disperse the intermediate 3 in DMF and transfer it to the above flask, stir and heat to 65°C for 1 hour, cool, centrifuge, take the precipitate, ultrasonically disperse it in DMF, and dry to obtain a flame retardant; the usage ratio of magnesium hydroxide to intermediate 3 is 30g:10g.

2. The high temperature resistant 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 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 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: The following steps are involved: The raw materials are weighed according to weight, and the nylon resin, flame retardant, lubricant, antioxidant and ultraviolet absorber are mixed evenly, and then added into the twin-screw extruder through the main feed. The flame retardant is then added into the twin-screw extruder through the side feed. After extrusion, drawing, cooling, pelletizing and drying, a high-temperature resistant flame-retardant nylon composite material is obtained.