Preparation method and application of polyamide composite material

Abstract

The invention discloses a preparation method of a polyamide composite material, and belongs to the technical field of polyamide composite materials. Comprising the following raw materials in parts by weight: 57-69 parts of PA66 resin, 4-12 parts of a heat stabilizer, 1-3 parts of a flexibilizer, 2-5 parts of a lubrication dispersant and 0.8-2.4 parts of an antioxidant. According to the prepared heat stabilizer, the heat stability of the material in a high-temperature environment is remarkably improved, and compared with a traditional heat stabilizer, the heat stabilizer is good in compatibility with a polyamide matrix and easier to disperse, so that the heat resistance is more effectively exerted; the heat stabilizer is prepared through two-step reaction, process steps are clear, conditions are controllable, and the method is suitable for industrial production; therefore, the polyamide composite material prepared by the invention has excellent thermal stability, is particularly suitable for parts of an automobile engine intake manifold and the like in a high-temperature environment, and has important application value in the field of automobile industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyamide composite materials, and in particular relates to a preparation method and application of a polyamide composite material. Background Art

[0002] As an important engineering plastic, polyamide is widely used in the automotive field due to its excellent mechanical properties, heat resistance, wear resistance and chemical stability, especially in engine peripheral components such as engine intake manifolds.

[0003] Traditional intake manifolds are mostly made of metal (such as aluminum alloy). Although they are strong, they are heavy, complex to process, and not conducive to lightweight engine design. As the automotive industry continues to demand higher fuel economy and emissions, lightweight and chemically resistant plastic intake manifolds are becoming the mainstream choice. Polyamide is the preferred material due to its excellent overall performance.

[0004] However, as demand continues to grow, the performance of traditional polyamide materials is increasingly failing to meet the requirements for engine intake manifolds. For example, the high temperatures near the engine significantly reduce the mechanical strength and dimensional stability of traditional polyamide materials. This severely restricts the application of polyamide materials in engine intake manifolds. Therefore, addressing these issues is crucial to meet the increasing demands of engine intake manifold technology. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a preparation method and application of a polyamide composite material.

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

[0007] A method for preparing a polyamide composite material comprises the following steps:

[0008] A1. Dry the PA66 resin in a drying oven; add the dried PA66 resin, a heat stabilizer, a toughening agent, a lubricating dispersant, and an antioxidant into a high-speed mixer and mix well to obtain a premix;

[0009] A2. The premix obtained in step A1 is added from the main feeding port of the extruder, melt-blended, extruded, and granulated in the extruder to obtain a polyamide composite material.

[0010] Furthermore, the raw materials are calculated in parts by weight as follows: 57-69 parts of PA66 resin, 4-12 parts of heat stabilizer, 1-3 parts of toughening agent, 2-5 parts of lubricating dispersant and 0.8-2.4 parts of antioxidant.

[0011] Furthermore, the drying condition is 60-80° C. for 12-24 hours.

[0012] Furthermore, the toughening agent is one of polyethylene grafted with maleic anhydride, polypropylene grafted with maleic anhydride and ethylene-octene copolymer grafted with maleic anhydride.

[0013] Furthermore, the lubricating dispersant is one of montan wax, polypropylene wax, erucamide and zinc stearate.

[0014] Furthermore, the antioxidant is one of antioxidant 1010 and antioxidant 264.

[0015] Furthermore, the thermal stabilizer is prepared by the following steps:

[0016] S1. Add 1,3-acetonedicarboxylic acid, diethylaminosulfur trifluoride and dichloromethane as solvent to a three-necked flask equipped with a thermometer, a magnetic stirrer and a condenser. Stir and react for 30-60 minutes at room temperature. After the reaction is complete, filter and take the filter cake, wash it with anhydrous ethanol three times, and dry it to obtain a heat stabilizer intermediate product.

[0017] In step S1, diethylaminosulfur trifluoride is used as a fluorination agent to convert the carbonyl group on 1,3-acetonedicarboxylic acid into a difluorinated compound. The reaction formula is as follows:

[0018]

[0019] S2. In a three-necked flask equipped with a thermometer, a magnetic stirrer, and a condenser, 3-amino-5-methylisoxazole, a heat stabilizer intermediate, and pyridine solvent were added and mixed. The mixture was magnetically stirred for 10-20 minutes to fully mix the raw materials. Then, dicyclohexylcarbodiimide (dehydrating agent) was added and the temperature was raised to 55° C. The reaction was allowed to react for 2-4 hours. After the reaction was completed, the mixture was rotary evaporated and purified by column chromatography to obtain a heat stabilizer.

[0020] In step S2, dicyclohexylcarbodiimide is used as a catalyst, and 3-amino-5-methylisoxazole undergoes an amidation reaction with the heat stabilizer intermediate product. The molar ratio of the two is 2:1, and 3-amino-5-methylisoxazole needs to be in excess to allow the reaction to proceed fully. The reaction formula is as follows:

[0021]

[0022] The present invention prepares a heat stabilizer through a two-step reaction. Two isoxazole rings and two fluorocarbon bond structures are introduced into the prepared heat stabilizer. The isoxazole ring structure is a five-membered heterocyclic ring. This special structure can disperse electron density through a conjugation effect, reduce the reactivity of the ring, and thus improve the thermal stability of the polyamide matrix. The fluorocarbon bond is one of the strongest known single bonds. Its high bond energy and unique electronic structure further enhance the thermal stability of the polyamide matrix. Finally, the prepared heat stabilizer also contains two amide groups, which can improve the compatibility of the heat stabilizer with the polyamide matrix, making it easier to disperse and better exerting heat resistance.

[0023] Furthermore, the ratio of the amount of 1,3-acetonedicarboxylic acid, DAST, and dichloromethane is 14.6 g:6.3 g:75 mL.

[0024] Furthermore, the ratio of the amount of 3-amino-5-methylisoxazole, the heat stabilizer intermediate product, pyridine, and dicyclohexylcarbodiimide is 21.3 g:16.8 g:150 mL:41.2 g.

[0025] Beneficial effects of the present invention:

[0026] 1. The heat stabilizer prepared by the present invention significantly improves the thermal stability of the material under high temperature environment by introducing isoxazole ring and fluorocarbon bond structure, utilizing conjugation effect and high bond energy characteristics, and solves the problem of decreased mechanical strength and dimensional stability of traditional polyamide materials under high temperature;

[0027] 2. Compared with traditional heat stabilizers, heat stabilizers contain amide groups, which make them more compatible with the polyamide matrix and easier to disperse, thus more effectively exerting heat resistance;

[0028] 3. The thermal stabilizer is prepared through a two-step reaction (fluorination reaction and amidation reaction), with clear process steps and controllable conditions, which is suitable for industrial production;

[0029] Therefore, the polyamide composite material prepared by the present invention has excellent thermal stability and is particularly suitable for components in high-temperature environments such as automobile engine intake manifolds, and has important application value in the automotive industry. DETAILED DESCRIPTION

[0030] 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.

[0031] Example 1

[0032] Preparation of heat stabilizer:

[0033] S1. In a three-necked flask equipped with a thermometer, a magnetic stirrer and a condenser, 14.6 g of 1,3-acetone dicarboxylic acid, 6.3 g of diethylaminosulfur trifluoride and 75 mL of dichloromethane were added as a solvent. The mixture was stirred at room temperature for 30 min. After the reaction was completed, the filter cake was filtered and washed with anhydrous ethanol three times, and dried to obtain a heat stabilizer intermediate product.

[0034] S2. In a three-necked flask equipped with a thermometer, a magnetic stirrer and a condenser, 21.3 g of 3-amino-5-methylisoxazole, 16.8 g of the intermediate product of the heat stabilizer and 150 mL of the solvent pyridine were added and mixed. The mixture was magnetically stirred for 10 minutes to ensure that the raw materials were fully mixed. Then, 41.2 g of dicyclohexylcarbodiimide was added and the temperature was raised to 55 ° C. The reaction was allowed to react for 2 hours. After the reaction was completed, the mixture was rotary evaporated and purified by column chromatography to obtain the heat stabilizer.

[0035] Example 2

[0036] Preparation of heat stabilizer:

[0037] S1. In a three-necked flask equipped with a thermometer, a magnetic stirrer and a condenser, 29.2 g of 1,3-acetone dicarboxylic acid, 12.6 g of diethylaminosulfur trifluoride and 150 mL of dichloromethane were added as a solvent. The mixture was stirred at room temperature for 60 min. After the reaction was completed, the filter cake was filtered and washed with anhydrous ethanol three times, and dried to obtain a heat stabilizer intermediate product.

[0038] S2. In a three-necked flask equipped with a thermometer, a magnetic stirrer and a condenser, 42.6 g of 3-amino-5-methylisoxazole, 33.6 g of the thermal stabilizer intermediate product and 300 mL of solvent pyridine were added and mixed. The mixture was magnetically stirred for 20 minutes to ensure that the raw materials were fully mixed. Then, 82.4 g of dicyclohexylcarbodiimide was added and the temperature was raised to 55 ° C. The reaction was allowed to react for 4 hours. After the reaction was completed, the mixture was rotary evaporated and purified by column chromatography to obtain a thermal stabilizer.

[0039] Example 3

[0040] Preparation of polyamide composite materials:

[0041] A1. Dry 57-69 g of PA66 resin in a drying oven at 60-80° C. for 12-24 h. Add the dried PA66 resin, 4-12 g of the heat stabilizer prepared in Example 1, 1-3 g of polyethylene grafted maleic anhydride, 2-5 g of montan wax, and 0.8-2.4 g of antioxidant 264 to a high-speed mixer and mix well to obtain a premix.

[0042] A2. The premix obtained in step A1 is added from the main feeding port of the extruder, melt-blended, extruded, and granulated in the extruder to obtain a polyamide composite material.

[0043] Example 4

[0044] Preparation of polyamide composite materials:

[0045] A1. Dry 57-69 g of PA66 resin in a drying oven at 60-80° C. for 12-24 h. Add the dried PA66 resin, 4-12 g of the heat stabilizer prepared in Example 2, 1-3 g of polypropylene grafted maleic anhydride, 2-5 g of polypropylene wax, and 0.8-2.4 g of antioxidant 1010 to a high-speed mixer and mix well to obtain a premix.

[0046] A2. The premix obtained in step A1 is added from the main feeding port of the extruder, melt-blended, extruded, and granulated in the extruder to obtain a polyamide composite material.

[0047] Example 5

[0048] Preparation of polyamide composite materials:

[0049] A1. Dry 57-69 g of PA66 resin in a drying oven at 60-80° C. for 12-24 h. Add the dried PA66 resin, 4-12 g of the heat stabilizer prepared in Example 2, 1-3 g of ethylene-octene copolymer grafted maleic anhydride, 2-5 g of erucamide, and 0.8-2.4 g of antioxidant 1010 to a high-speed mixer and mix well to obtain a premix.

[0050] A2. The premix obtained in step A1 is added from the main feeding port of the extruder, melt-blended, extruded, and granulated in the extruder to obtain a polyamide composite material.

[0051] Comparative Example 1

[0052] An organic tin heat stabilizer (dibutyltin dilaurate) was used to replace the heat stabilizer in Example 5, and the remaining steps were the same as those in Example 5 to prepare a composite material.

[0053] Comparative Example 2

[0054] Use ordinary polyamide material.

[0055] The heat resistance of Examples 3, 4, and 5 and Comparative Examples 1 and 2 was tested;

[0056] The measured results are as follows:

[0057] Test items Heat deformation temperature / ℃ Test standards GB / T 1634.2-2004 Example 3 187 Example 4 192 Example 5 195 Comparative Example 1 143 Comparative Example 2 89

[0058] As can be seen from the above table, the polyamide composite material prepared in the examples of the present invention has better thermal stability than the comparative example; therefore, the present invention is particularly suitable for components in high-temperature environments such as automobile engine intake manifolds, and has important application value in the automotive industry.

[0059] 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.

[0060] The above contents are merely examples and explanations of the present invention. Any modifications or additions made by those skilled in the art to the described specific embodiments, or replacements made in a similar manner, shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a polyamide composite material, characterized in that: The following steps are involved: A1. Dry PA66 resin in a drying oven; then add it to a high-speed mixer with a heat stabilizer, a toughening agent, a lubricating dispersant, and an antioxidant and mix well to obtain a premix; A2. The premix obtained in step A1 is melt-blended in an extruder, extruded, and granulated to obtain a polyamide composite material.

2. The method for preparing a polyamide composite material according to claim 1, wherein The thermal stabilizer is prepared by the following steps: S1. Add 1,3-acetonedicarboxylic acid, diethylaminosulfur trifluoride and dichloromethane as solvent to a flask, stir and react at room temperature for 30-60 minutes. The reaction is completed to obtain a heat stabilizer intermediate product; S2. In a flask, add 3-amino-5-methylisoxazole, the intermediate product of the heat stabilizer and the solvent pyridine, mix, add dicyclohexylcarbodiimide after magnetic stirring, and react at 55° C. for 2-4 hours. The reaction is completed to obtain a heat stabilizer.

3. The method for preparing the polyamide composite material according to claim 2, wherein: The usage ratio of the 1,3-acetonedicarboxylic acid, DAST, and dichloromethane is 14.6 g:6.3 g:75 mL.

4. The method for preparing a polyamide composite material according to claim 2, wherein: The ratio of the amount of 3-amino-5-methylisoxazole, the heat stabilizer intermediate product, pyridine, and dicyclohexylcarbodiimide is 21.3 g:16.8 g:150 mL:41.2 g.

5. The method for preparing a polyamide composite material according to claim 1, wherein: The raw materials are calculated in parts by weight as follows: 57-69 parts of PA66 resin, 4-12 parts of heat stabilizer, 1-3 parts of toughening agent, 2-5 parts of lubricating dispersant and 0.8-2.4 parts of antioxidant.

6. The method for preparing a polyamide composite material according to claim 1, wherein: The drying conditions are: drying at 60-80°C for 12-24 hours.

7. The method for preparing a polyamide composite material according to claim 1, wherein: The toughening agent is one of polyethylene grafted with maleic anhydride, polypropylene grafted with maleic anhydride and ethylene-octene copolymer grafted with maleic anhydride.

8. The method for preparing a polyamide composite material according to claim 1, wherein: The antioxidant is one of antioxidant 1010 and antioxidant 264.

9. The method for preparing the polyamide composite material according to claim 1, and its application in the field of engine intake manifold.

Images