A lightweight heat-resistant polyamide composite material for automobile instrument panel cross beam

Abstract

The invention relates to the technical field of polyamide composite materials, and discloses a light heat-resistant polyamide composite material for a cross beam of an automobile instrument panel. The invention provides a light heat-resistant polyamide composite material for a cross beam of an automobile instrument panel by adding polyamide, triazine-based polyamide, modified graphene oxide and an antioxidant into a twin-screw extruder for melt blending, extrusion and granulation; and then performing injection molding by an injection molding machine to obtain the light heat-resistant polyamide composite material for a cross beam of an automobile instrument panel; phosphorus elements and nitrogen elements contained in the triazine-based polyamide and nitrogen elements in the modified graphene oxide constitute a flame retardant system, which has a good flame retardant effect; a large amount of amide structures contained in the triazine-based polyamide and the polyamide also have good interface compatibility, wherein the triazine group and the graphene oxide themselves have good heat resistance, thereby improving the heat resistance of the material.

Description

Technical Field

[0001] The invention relates to the technical field of polyamide composite materials, in particular to a lightweight heat-resistant polyamide composite material for a cross beam of an automobile instrument panel. Background Art

[0002] The crossbeam of the car dashboard supports the equipment and decorative parts required for human-machine interface control, and together with other safety parts, it constitutes a safety system. With the development of society, people's requirements for car decorative parts are getting higher and higher.

[0003] For example, patent CN104554485A reports a method for manufacturing a cross beam of an automobile instrument panel, which solves the problem of low comprehensive performance such as density, specific stiffness and specific strength of existing materials used in manufacturing cross beams of automobile instrument panels, and has the advantages of simple method, low cost and easy processing; however, its flame retardant and heat resistant properties are not improved.

[0004] Polyamide, commonly known as nylon, has the advantages of good mechanical properties, heat resistance, wear resistance, chemical resistance and self-lubrication, and has a low friction coefficient and certain flame retardancy. Therefore, the present invention uses polyamide, triazine-based polyamide and modified graphene oxide together to synergistically improve their flame retardancy and heat resistance. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] In view of the deficiencies in the prior art, the present invention provides a lightweight heat-resistant polyamide composite material for a cross beam of an automobile instrument panel, which has good flame retardant and heat-resistant effects.

[0007] (II) Technical solution

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a lightweight heat-resistant polyamide composite material for a cross beam of an automobile instrument panel, comprising the following components by weight: 70-100 parts by weight of polyamide, 6-10 parts by weight of triazine-based polyamide, 4-7 parts by weight of modified graphene oxide, and 1-2 parts by weight of antioxidant 1076.

[0009] Preferably, it is characterized in that the preparation method of the triazine-based polyamide is:

[0010] (1) adding biphenyltetracarboxylic acid dianhydride, 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane and pyridine catalyst to an acetone solvent, heating to 75-90° C. and stirring for reaction for 15-25 hours, and then removing the solvent by distillation under reduced pressure, washing with petroleum ether, and drying to obtain an intermediate;

[0011] (2) dissolving hydroxyethyl hexahydro-s-triazine and the intermediate in N,N-dimethylformamide solvent, then adding N,N-dicyclohexylcarbodiimide and 4-dimethylaminopyridine, reflux at 120-135° C. for 20-35 hours, and after the reaction, removing the solvent by distillation under reduced pressure, precipitating, filtering and washing to obtain a carboxylated polymer;

[0012] (3) Adding the carboxylated polymer and ethylenediamine to N,N-dimethylformamide solvent, stirring to dissolve, then adding pyridine and triphenyl phosphite, refluxing at 125-135° C. for 12-16 hours, filtering the solvent after the end, and washing the product with deionized water and ethanol in turn to obtain triazine-based polyamide.

[0013] Preferably, the mass ratio of biphenyltetracarboxylic dianhydride, 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane and pyridine catalyst in (1) is 1:1.2-2.3:0.01-0.03.

[0014] Preferably, the mass ratio of hydroxyethyl hexahydro-s-triazine, intermediate, N,N-dicyclohexylcarbodiimide and 4-dimethylaminopyridine in (2) is 1.1-1.3:1:0.02-0.03:0.01-0.03.

[0015] Preferably, the mass ratio of the carboxylated polymer, ethylenediamine, pyridine and triphenyl phosphite in (3) is 1:0.9-1.3:0.02-0.04:0.03-0.05.

[0016] Preferably, the preparation method of the modified graphene oxide is:

[0017] S1. 1-1.5 g of graphene oxide is ultrasonically dispersed in 3-5 g of thionyl chloride. After uniform dispersion, the mixture is reacted at 70-85° C. for 20-26 h. After the reaction is completed, the mixture is filtered, washed and dried to obtain graphene chloride;

[0018] S2. Add 2-2.5 g of chlorinated graphene and 1.5-2.3 g of hydroxyethyl hexahydrotriazine to N,N-dimethylformamide solvent, stir evenly, then add 0.01-0.02 g of triethylamine catalyst, react at 75-100°C for 8-10 hours, and then perform reduced pressure distillation, wash with petroleum ether, filter and dry to obtain modified graphene oxide.

[0019] Preferably, the preparation method of the lightweight heat-resistant polyamide composite material for the automobile dashboard cross beam comprises the following steps: adding polyamide, triazine-based polyamide, modified graphene oxide, and antioxidant 1076 into a twin-screw extruder for melt blending, extrusion and granulation, the blending temperature is 220-240°C, and the extrusion temperature is 210-225°C; then injection molding by an injection molding machine, the injection molding temperature is 220-245°C, and the lightweight heat-resistant polyamide composite material for the automobile dashboard cross beam is obtained.

[0020] (III) Beneficial technical effects

[0021] The invention adds polyamide, triazine-based polyamide, modified graphene oxide and antioxidant 1076 into a twin-screw extruder for melt blending, extrusion and granulation; and then performs injection molding by an injection molding machine to obtain a light heat-resistant polyamide composite material for a cross beam of an automobile dashboard.

[0022] Biphenyltetracarboxylic acid dianhydride and 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane are reacted under the action of pyridine catalyst to obtain an intermediate; then hydroxyethyl hexahydro-s-triazine and the intermediate are reacted under the action of N,N-dicyclohexylcarbodiimide and 4-dimethylaminopyridine to obtain a carboxylated polymer; the carboxylated polymer is further subjected to an amidation reaction with ethylenediamine to obtain a triazine-based polyamide; and acylated graphene and hydroxyethyl hexahydro-s-triazine are reacted under the action of triethylamine catalyst to obtain modified graphene oxide.

[0023] The phosphorus and nitrogen elements contained in triazine-based polyamide and the nitrogen element in modified graphene oxide constitute a flame retardant system. The nitrogen element can generate non-flammable gas when heated to dilute the concentration of flammable gas to achieve the purpose of flame retardancy. The phosphorus element contained in it can generate phosphoric acid and metaphosphoric acid, which are strong dehydrating substances, when heated, which can promote the dehydration of the material into carbon and can further form a polyphosphoric acid substance on the surface of the substrate, isolating material transportation and energy transfer to achieve a good flame retardant effect. The triazine-based polyamide contains a large amount of amide structure and polyamide also has good interface compatibility. The triazine group and graphene oxide themselves have good heat resistance, which improves the heat resistance of the material. DETAILED DESCRIPTION

[0024] Example 1

[0025] (1) Add 1 g of biphenyltetracarboxylic dianhydride, 1.2 g of 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane and 0.01 g of pyridine catalyst to 60 ml of acetone solvent, heat to 75° C., stir and react for 15 h, and then remove the solvent by distillation under reduced pressure, wash with petroleum ether and dry to obtain an intermediate;

[0026] (2) dissolving 1.1 g of hydroxyethyl hexahydro-s-triazine and 1 g of the intermediate in 50 ml of N,N-dimethylformamide solvent, then adding 0.02 g of N,N-dicyclohexylcarbodiimide and 0.01 g of 4-dimethylaminopyridine, and reflux at 120° C. for 20 h. After the reaction, the solvent is removed by distillation under reduced pressure, precipitated, filtered and washed to obtain a carboxylated polymer;

[0027] (3) adding 1 g of the carboxylated polymer and 1.35 g of ethylenediamine to 70 ml of N,N-dimethylformamide solvent, stirring to dissolve, then adding 0.03 g of pyridine and 0.04 g of triphenyl phosphite, and refluxing at 125° C. for 12 h. After the end, filtering the solvent, and washing the product with deionized water and ethanol in turn to obtain a triazine-based polyamide;

[0028] (4) ultrasonically dispersing 1 g of graphene oxide into 3 g of thionyl chloride, and after uniform dispersion, reacting at 70° C. for 20 h. After completion, filtering, washing and drying to obtain chlorinated graphene;

[0029] (5) Add 2 g of chlorinated graphene and 1.5 g of hydroxyethyl hexahydro-s-triazine to 50 ml of N,N-dimethylformamide solvent, stir evenly, then add 0.01 g of triethylamine catalyst, react at 75 ° C. for 8 h, and then distill under reduced pressure, wash with petroleum ether, filter and dry to obtain modified graphene oxide;

[0030] (6) 70 parts by weight of polyamide, 6 parts by weight of triazine-based polyamide, 4 parts by weight of modified graphene oxide, and 1 part by weight of antioxidant 1076 are added to a twin-screw extruder for melt blending, extrusion and granulation, the blending temperature is 220°C, and the extrusion temperature is 210°C; then, the mixture is injection molded by an injection molding machine, and the injection molding temperature is 220°C to obtain a lightweight heat-resistant polyamide composite material for a cross beam of an automobile dashboard.

[0031] Example 2

[0032] (1) Add 2 g of biphenyltetracarboxylic dianhydride, 4.6 g of 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane and 0.06 g of pyridine catalyst to 90 ml of acetone solvent, heat to 90° C. and stir to react for 25 h. After reaction, remove the solvent by distillation under reduced pressure, wash with petroleum ether and dry to obtain an intermediate;

[0033] (2) dissolving 1.3 g of hydroxyethyl hexahydro-s-triazine and 1 g of the intermediate in 70 ml of N,N-dimethylformamide solvent, then adding 0.03 g of N,N-dicyclohexylcarbodiimide and 0.03 g of 4-dimethylaminopyridine, and reflux at 135° C. for 35 h. After the reaction, the solvent is removed by distillation under reduced pressure, precipitated, filtered and washed to obtain a carboxylated polymer;

[0034] (3) Add 1.5 g of the carboxylated polymer and 1.95 g of ethylenediamine to 100 ml of N,N-dimethylformamide solvent, stir to dissolve, then add 0.06 g of pyridine and 0.07 g of triphenyl phosphite, reflux at 135° C. for 16 h, filter the solvent after the end, wash the product with deionized water and ethanol in turn, and obtain a triazine-based polyamide;

[0035] (4) ultrasonically dispersing 1.5 g of graphene oxide into 5 g of thionyl chloride, and after uniform dispersion, reacting at 85° C. for 26 h. After completion, filtering, washing and drying to obtain chlorinated graphene;

[0036] (5) Add 2.5 g of chlorinated graphene and 2.3 g of hydroxyethyl hexahydro-s-triazine to 80 ml of N,N-dimethylformamide solvent, stir evenly, then add 0.02 g of triethylamine catalyst, react at 100 ° C. for 10 h, and then distill under reduced pressure, wash with petroleum ether, filter and dry to obtain modified graphene oxide;

[0037] (6) 100 parts by weight of polyamide, 10 parts by weight of triazine-based polyamide, 7 parts by weight of modified graphene oxide, and 2 parts by weight of antioxidant 1076 are added to a twin-screw extruder for melt blending, extrusion and granulation, the blending temperature is 240°C, and the extrusion temperature is 225°C; then, the mixture is injection molded by an injection molding machine, and the injection molding temperature is 245°C to obtain a lightweight heat-resistant polyamide composite material for a cross beam of an automobile dashboard.

[0038] Example 3

[0039] (1) Add 1.5 g of biphenyltetracarboxylic dianhydride, 2.9 g of 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane and 0.035 g of pyridine catalyst to 75 ml of acetone solvent, heat to 82.5° C. and stir to react for 20 h. After reaction, remove the solvent by distillation under reduced pressure, wash with petroleum ether and dry to obtain an intermediate;

[0040] (2) dissolving 1.2 g of hydroxyethyl hexahydro-s-triazine and 1 g of the intermediate in 60 ml of N,N-dimethylformamide solvent, then adding 0.025 g of N,N-dicyclohexylcarbodiimide and 0.02 g of 4-dimethylaminopyridine, and reflux at 127.5° C. for 27.5 h. After the reaction, the solvent is removed by distillation under reduced pressure, precipitated, filtered and washed to obtain a carboxylated polymer;

[0041] (3) Add 1.25 g of carboxylated polymer and 1.65 g of ethylenediamine to 85 ml of N,N-dimethylformamide solvent, stir to dissolve, then add 0.045 g of pyridine and 0.055 g of triphenyl phosphite, reflux at 130° C. for 14 h, filter the solvent after the end, wash the product with deionized water and ethanol in turn, to obtain triazine-based polyamide;

[0042] (4) ultrasonically dispersing 1.25 g of graphene oxide into 4 g of thionyl chloride, and after uniform dispersion, reacting at 77.5° C. for 23 h. After completion, filtering, washing and drying to obtain chlorinated graphene;

[0043] (5) Add 2.25 g of chlorinated graphene and 1.9 g of hydroxyethyl hexahydro-s-triazine to 65 ml of N,N-dimethylformamide solvent, stir evenly, then add 0.015 g of triethylamine catalyst, react at 87.5 ° C. for 9 h, and then distill under reduced pressure, wash with petroleum ether, filter and dry to obtain modified graphene oxide;

[0044] (6) 85 parts by weight of polyamide, 8 parts by weight of triazine-based polyamide, 5.5 parts by weight of modified graphene oxide, and 1.5 parts by weight of antioxidant 1076 are added to a twin-screw extruder for melt blending, extrusion and granulation, the blending temperature is 230°C, and the extrusion temperature is 217.5°C; then, the mixture is injection molded by an injection molding machine, and the injection molding temperature is 232.5°C to obtain a lightweight heat-resistant polyamide composite material for a cross beam of an automobile dashboard.

[0045] Example 4

[0046] (1) Add 1 g of biphenyltetracarboxylic dianhydride, 1.2 g of 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane and 0.01 g of pyridine catalyst to 60 ml of acetone solvent, heat to 75° C., stir and react for 15 h, and then remove the solvent by distillation under reduced pressure, wash with petroleum ether and dry to obtain an intermediate;

[0047] (2) dissolving 1.1 g of hydroxyethyl hexahydro-s-triazine and 1 g of the intermediate in 50 ml of N,N-dimethylformamide solvent, then adding 0.02 g of N,N-dicyclohexylcarbodiimide and 0.01 g of 4-dimethylaminopyridine, and reflux at 120° C. for 20 h. After the reaction, the solvent is removed by distillation under reduced pressure, precipitated, filtered and washed to obtain a carboxylated polymer;

[0048] (3) Add 1.5 g of the carboxylated polymer and 1.95 g of ethylenediamine to 100 ml of N,N-dimethylformamide solvent, stir to dissolve, then add 0.06 g of pyridine and 0.07 g of triphenyl phosphite, reflux at 135° C. for 16 h, filter the solvent after the end, wash the product with deionized water and ethanol in turn, and obtain a triazine-based polyamide;

[0049] (4) ultrasonically dispersing 1.5 g of graphene oxide into 5 g of thionyl chloride, and after uniform dispersion, reacting at 85° C. for 26 h. After completion, filtering, washing and drying to obtain chlorinated graphene;

[0050] (5) Add 2.25 g of chlorinated graphene and 1.9 g of hydroxyethyl hexahydro-s-triazine to 65 ml of N,N-dimethylformamide solvent, stir evenly, then add 0.015 g of triethylamine catalyst, react at 87.5 ° C. for 9 h, and then distill under reduced pressure, wash with petroleum ether, filter and dry to obtain modified graphene oxide;

[0051] (6) 85 parts by weight of polyamide, 8 parts by weight of triazine-based polyamide, 5.5 parts by weight of modified graphene oxide, and 1.5 parts by weight of antioxidant 1076 are added to a twin-screw extruder for melt blending, extrusion and granulation, the blending temperature is 230°C, and the extrusion temperature is 217.5°C; then, the mixture is injection molded by an injection molding machine, and the injection molding temperature is 232.5°C to obtain a lightweight heat-resistant polyamide composite material for a cross beam of an automobile dashboard.

[0052] Example 5

[0053] (1) Add 2 g of biphenyltetracarboxylic dianhydride, 4.6 g of 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane and 0.06 g of pyridine catalyst to 90 ml of acetone solvent, heat to 90° C. and stir to react for 25 h. After reaction, remove the solvent by distillation under reduced pressure, wash with petroleum ether and dry to obtain an intermediate;

[0054] (2) dissolving 1.3 g of hydroxyethyl hexahydro-s-triazine and 1 g of the intermediate in 70 ml of N,N-dimethylformamide solvent, then adding 0.03 g of N,N-dicyclohexylcarbodiimide and 0.03 g of 4-dimethylaminopyridine, and reflux at 135° C. for 35 h. After the reaction, the solvent is removed by distillation under reduced pressure, precipitated, filtered and washed to obtain a carboxylated polymer;

[0055] (3) Add 1.25 g of carboxylated polymer and 1.65 g of ethylenediamine to 85 ml of N,N-dimethylformamide solvent, stir to dissolve, then add 0.045 g of pyridine and 0.055 g of triphenyl phosphite, reflux at 130° C. for 14 h, filter the solvent after the end, wash the product with deionized water and ethanol in turn, to obtain triazine-based polyamide;

[0056] (4) ultrasonically dispersing 1.25 g of graphene oxide into 4 g of thionyl chloride, and after uniform dispersion, reacting at 77.5° C. for 23 h. After completion, filtering, washing and drying to obtain chlorinated graphene;

[0057] (5) Add 2 g of chlorinated graphene and 1.5 g of hydroxyethyl hexahydro-s-triazine to 50 ml of N,N-dimethylformamide solvent, stir evenly, then add 0.01 g of triethylamine catalyst, react at 75 ° C. for 8 h, and then distill under reduced pressure, wash with petroleum ether, filter and dry to obtain modified graphene oxide;

[0058] (6) 70 parts by weight of polyamide, 6 parts by weight of triazine-based polyamide, 4 parts by weight of modified graphene oxide, and 1 part by weight of antioxidant 1076 are added to a twin-screw extruder for melt blending, extrusion and granulation, the blending temperature is 220°C, and the extrusion temperature is 210°C; then, the mixture is injection molded by an injection molding machine, and the injection molding temperature is 220°C to obtain a lightweight heat-resistant polyamide composite material for a cross beam of an automobile dashboard.

[0059] Example 6

[0060] (1) Add 1.5 g of biphenyltetracarboxylic dianhydride, 2.9 g of 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane and 0.035 g of pyridine catalyst to 75 ml of acetone solvent, heat to 82.5° C. and stir to react for 20 h. After reaction, remove the solvent by distillation under reduced pressure, wash with petroleum ether and dry to obtain an intermediate;

[0061] (2) dissolving 1.2 g of hydroxyethyl hexahydro-s-triazine and 1 g of the intermediate in 60 ml of N,N-dimethylformamide solvent, then adding 0.025 g of N,N-dicyclohexylcarbodiimide and 0.02 g of 4-dimethylaminopyridine, and reflux at 127.5° C. for 27.5 h. After the reaction, the solvent is removed by distillation under reduced pressure, precipitated, filtered and washed to obtain a carboxylated polymer;

[0062] (3) adding 1 g of the carboxylated polymer and 1.35 g of ethylenediamine to 70 ml of N,N-dimethylformamide solvent, stirring to dissolve, then adding 0.03 g of pyridine and 0.04 g of triphenyl phosphite, and refluxing at 125° C. for 12 h. After the end, filtering the solvent, and washing the product with deionized water and ethanol in turn to obtain a triazine-based polyamide;

[0063] (4) ultrasonically dispersing 1 g of graphene oxide into 3 g of thionyl chloride, and after uniform dispersion, reacting at 70° C. for 20 h. After completion, filtering, washing and drying to obtain chlorinated graphene;

[0064] (5) Add 2 g of chlorinated graphene and 1.5 g of hydroxyethyl hexahydro-s-triazine to 50 ml of N,N-dimethylformamide solvent, stir evenly, then add 0.01 g of triethylamine catalyst, react at 75 ° C. for 8 h, and then distill under reduced pressure, wash with petroleum ether, filter and dry to obtain modified graphene oxide;

[0065] (6) 100 parts by weight of polyamide, 10 parts by weight of triazine-based polyamide, 7 parts by weight of modified graphene oxide, and 2 parts by weight of antioxidant 1076 are added to a twin-screw extruder for melt blending, extrusion and granulation, the blending temperature is 240°C, and the extrusion temperature is 225°C; then, the mixture is injection molded by an injection molding machine, and the injection molding temperature is 245°C to obtain a lightweight heat-resistant polyamide composite material for a cross beam of an automobile dashboard.

[0066] Comparative Example 1

[0067] (1) 100 parts by weight of polyamide, 7 parts by weight of modified graphene oxide, and 2 parts by weight of antioxidant 1076 are added to a twin-screw extruder for melt blending, extrusion, and granulation, the blending temperature is 240° C., and the extrusion temperature is 225° C.; then, the mixture is injection molded by an injection molding machine, and the injection molding temperature is 245° C., to obtain a lightweight heat-resistant polyamide composite material for a cross beam of an automobile instrument panel.

[0068] Comparative Example 2

[0069] (1) 100 parts by weight of polyamide, 10 parts by weight of triazine-based polyamide, and 2 parts by weight of antioxidant 1076 are added to a twin-screw extruder for melt blending, extrusion, and granulation, with the blending temperature being 240° C. and the extrusion temperature being 225° C.; and then injection molding is performed by an injection molding machine, with the injection molding temperature being 245° C., to obtain a lightweight heat-resistant polyamide composite material for a cross beam of an automobile instrument panel.

[0070] Performance Test:

[0071] Oxygen index (LOI) test The flame retardancy of the sample is tested using a digital oxygen index meter.

[0072] Vertical burning test (UL-94) uses CZF-2 vertical burning test instrument to test the samples. The test standard is based on ASTM D380. TPU sample size: 120×120×2mm 3 .

[0073] Table 1: Flame retardancy tests.

[0074] project Oxygen index (%) Vertical combustion Example 1 46.2 V-0 Example 2 49.6 V-0 Example 3 47.1 V-0 Example 4 47.5 V-0 Example 5 46.9 V-0 Example 6 47.6 V-0 Comparative Example 1 32.1 V-1 Comparative Example 2 33.5 V-1

[0075] It can be seen from Table 1 that the lightweight heat-resistant polyamide composite materials for automobile instrument panel cross beams prepared in the present invention, Examples 1-6 have better flame retardant effects than Comparative Examples 1-2.

[0076] The heat resistance of the material was tested using a thermogravimeter in a nitrogen atmosphere at a temperature range of 50-600°C; T 5％ is the decomposition temperature when the material loses 5% of its weight, T 50％ It is the decomposition temperature when the material loses 50% of its weight.

[0077] Table 2: Thermal performance tests.

[0078]

[0079]

[0080] It can be seen from Table 2 that the lightweight heat-resistant polyamide composite materials for automobile instrument panel cross beams prepared in the present invention, Examples 1-6 have better heat-resistant effects than Comparative Examples 1-2.

[0081] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0082] 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 specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A lightweight heat-resistant polyamide composite material for a cross beam of an automobile instrument panel, characterized in that: The invention comprises the following components by weight: 70-100 parts by weight of polyamide, 6-10 parts by weight of triazine-based polyamide, 4-7 parts by weight of modified graphene oxide, and 1-2 parts by weight of antioxidant 1076; The preparation method of the triazine-based polyamide is: (1) adding biphenyltetracarboxylic acid dianhydride, 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane and pyridine catalyst to an acetone solvent, heating to 75-90° C. and stirring for reaction for 15-25 hours, and then removing the solvent by distillation under reduced pressure, washing with petroleum ether, and drying to obtain an intermediate; (2) dissolving hydroxyethyl hexahydro-s-triazine and the intermediate in N,N-dimethylformamide solvent, then adding N,N-dicyclohexylcarbodiimide and 4-dimethylaminopyridine, reflux at 120-135° C. for 20-35 hours, and after the reaction, removing the solvent by distillation under reduced pressure, precipitating, filtering and washing to obtain a carboxylated polymer; (3) adding a carboxylated polymer and ethylenediamine to an N,N-dimethylformamide solvent, stirring to dissolve, then adding pyridine and triphenyl phosphite, refluxing at 125-135° C. for 12-16 hours, filtering the solvent after the end, and washing the product with deionized water and ethanol in turn to obtain a triazine-based polyamide; The mass ratio of biphenyltetracarboxylic dianhydride, 1-oxo-4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane and pyridine catalyst in (1) is 1:1.2-2.3:0.01-0.03; The mass ratio of hydroxyethyl hexahydro-s-triazine, intermediate, N,N-dicyclohexylcarbodiimide and 4-dimethylaminopyridine in (2) is 1.1-1.3:1:0.02-0.03:0.01-0.03; The mass ratio of the carboxylated polymer, ethylenediamine, pyridine and triphenyl phosphite in (3) is 1:0.9-1.3:0.02-0.04:0.03-0.05; The preparation method of the modified graphene oxide is: S1. 1-1.5 g of graphene oxide is ultrasonically dispersed in 3-5 g of thionyl chloride. After uniform dispersion, the mixture is reacted at 70-85° C. for 20-26 h. After the reaction is completed, the mixture is filtered, washed and dried to obtain graphene chloride; S2. Add 2-2.5 g of chlorinated graphene and 1.5-2.3 g of hydroxyethyl hexahydrotriazine to N,N-dimethylformamide solvent, stir evenly, then add 0.01-0.02 g of triethylamine catalyst, react at 75-100°C for 8-10 hours, and then perform reduced pressure distillation, wash with petroleum ether, filter and dry to obtain modified graphene oxide.

2. A method for preparing the lightweight heat-resistant polyamide composite material for automobile instrument panel cross beam according to claim 1, characterized in that: The method comprises the following steps: adding polyamide, triazine-based polyamide, modified graphene oxide and antioxidant 1076 into a twin-screw extruder for melt blending, extrusion and granulation, the blending temperature is 220-240°C, and the extrusion temperature is 210-225°C; and then injection molding by an injection molding machine, the injection molding temperature is 220-245°C, and a lightweight heat-resistant polyamide composite material for a cross beam of an automobile dashboard is obtained.

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