Hydrolysis-resistant reinforced high-temperature nylon composite material and preparation method thereof

Abstract

The invention discloses a hydrolysis-resistant reinforced high-temperature nylon composite material and a preparation method thereof, and relates to the technical field of nylon composite materials. The hydrolysis-resistant reinforced high-temperature nylon composite material is prepared from the following components in parts by mass: 50-85 parts of a nylon resin matrix, 10-40 parts of a reinforcing material, 4-8 parts of polyisobutene, 0.5-8 parts of a hydrolysis-resistant agent, 0.1-2 parts of an antioxidant and 0.2-3 parts of a lubricant. Through the synergistic effect of the antioxidant and the hydrolysis-resistant agent, a hydrolysis reaction chain is effectively blocked, and performance degradation of the material in a high-temperature and high-humidity environment is greatly delayed. The compatibility of the material and a resin matrix is improved, and the interface bonding force is enhanced by combining a gradient cooling process, so that the material still keeps high mechanical strength retention rate under extreme working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of nylon composite materials, and particularly relates to a hydrolysis-resistant reinforced high-temperature nylon composite material and a preparation method thereof. Background Art

[0002] With the continuous development of industrial technology, high-temperature nylon composite materials are increasingly widely used in high-end fields such as automobiles, electronics, and aerospace due to their excellent heat resistance, mechanical properties, and chemical stability. However, in practical applications, they face many challenges. In a high-temperature environment, the molecular chains of nylon are prone to increased movement. When interacting with water molecules, hydrolysis reactions are likely to occur, causing the molecular chains to break, resulting in a significant decline in the mechanical strength and heat resistance of the material, and affecting its service life. For example, components around automobile engines are in a high-temperature and high-humidity environment for a long time, and the decline of material performance accelerates.

[0003] In existing reinforced high-temperature nylon composite materials, although the mechanical strength is improved by adding reinforcing materials such as glass fibers, the compatibility between the reinforcing material and the nylon matrix is poor, and the interfacial bonding force is weak, resulting in low stress transfer efficiency, and the hydrolysis problem is not effectively solved. Some modification methods add ordinary hydrolysis-resistant agents, but the effect is limited and cannot meet the requirements of long-term high-temperature and high-humidity working conditions. In addition, during the processing of the material, due to the action of high temperature and high shear force, it is prone to oxidative degradation, resulting in unstable performance. Existing antioxidant addition schemes have problems such as uneven dispersion and low antioxidant efficiency, and it is difficult to effectively protect the material. At the same time, the processing fluidity and molding performance of the material also need to be improved to meet the molding requirements of complex parts. In summary, developing a high-temperature nylon composite material with excellent hydrolysis resistance, high strength, high fluidity, and good processing stability has become a technical problem to be solved urgently. Summary of the Invention

[0004] Aiming at the problems of insufficient hydrolysis resistance, poor enhanced compatibility, and limited antioxidant ability of existing high-temperature nylon composite materials, the present invention aims to provide a hydrolysis-resistant reinforced high-temperature nylon composite material and a preparation method thereof. By optimizing the formula and process, the hydrolysis resistance, mechanical strength, and processing performance of the material are significantly improved to meet the application requirements in fields such as aerospace and automobiles under high-temperature and high-humidity environments.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a hydrolysis-resistant reinforced high-temperature nylon composite material is prepared from components with the following mass ratios: 50 - 85 parts of a nylon resin matrix, 10 - 40 parts of a reinforcing material, 4 - 8 parts of polyisobutylene, 0.5 - 8 parts of a hydrolysis-resistant agent, 0.1 - 2 parts of an antioxidant, and 0.2 - 3 parts of a lubricant; The antioxidant has the structure shown in Formula 1: Formula 1; Wherein D represents deuterium; Z1 is selected from: O, S, N(R2), C(CH3)2; R1 is selected from: H, methyl, tert-butyl, phenyl, methoxy; R2 is selected from: H, tert-butyl, phenyl.

[0006] Furthermore, the nylon resin matrix is selected from at least one of polyhexamethylene terephthalamide, polynonamethylene terephthalamide, and polydecamethylene terephthalamide.

[0007] Furthermore, the nylon resin matrix has high-temperature stability performance at temperatures above 260 °C.

[0008] Furthermore, the reinforcing material is an inorganic mineral filler, selected from at least one of calcium carbonate, talcum powder, and mica, with an average particle size of 1-5 μm.

[0009] Furthermore, the lubricant is selected from at least one of calcium stearate, zinc stearate, and paraffin.

[0010] Furthermore, the hydrolysis-resistant agent is at least one of polycarbodiimide and pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0011] Furthermore, the antioxidant is any one of the compounds shown by the following structures:

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018] .

[0019] Furthermore, the synthesis steps of the antioxidant are: ; The first step: Intermediate 1 is synthesized from Raw material 1 and Raw material 2 through the Suzuki reaction; The second step: The antioxidant is synthesized from Intermediate 1 and Raw material 3 through the Williamson reaction.

[0020] A method for preparing a hydrolysis-resistant reinforced high-temperature nylon composite material includes the following steps: S1. Dry the nylon resin matrix and the reinforcing material at 110 - 130 °C for 4 - 6 hours to obtain dried materials. S2. Mix the dried materials with the polyisobutene, hydrolysis-resistant agent, antioxidant, and lubricant at 800 - 1200 r / min for 5 - 10 minutes to obtain a mixed material. S3. Add the mixed material into a twin-screw extruder, melt and extrude at 260 - 300 °C, and after water cooling, pelletizing, and drying, obtain a hydrolysis-resistant reinforced high-temperature nylon composite material.

[0021] Further, the temperature zones of the twin-screw extruder are controlled as follows: zone 1 at 260 - 270 °C, zone 2 at 270 - 280 °C, zone 3 at 280 - 290 °C, zone 4 at 290 - 300 °C, and the die head temperature is controlled at 285 - 295 °C.

[0022] Further, the water content of the reinforcing material after drying is ≤ 0.3 wt%.

[0023] Further, the water cooling adopts a gradient cooling process, specifically: the temperature of the primary cooling water is 60 - 70 °C, the temperature of the secondary cooling water is 40 - 50 °C, the temperature of the tertiary cooling water is 20 - 30 °C, and the cooling rate does not exceed 15 °C / min.

[0024] In the antioxidant of the present invention, the imino group in the antioxidant molecule reacts with free radicals (such as ROO·) by providing hydrogen atoms to generate stable free radical intermediates and terminate the oxidation chain reaction. The aromatic ring and heteroatoms form a conjugated system, enabling the free radical intermediate to be stabilized through electron delocalization. When substituted by a tert-butyl group or a phenyl group, the free radical is further stabilized through hyperconjugation. The bulky substituents (such as tert-butyl group, phenyl group) form a physical barrier to prevent the oxidation attack of the molecular chain at high temperatures. The rigid structure of the aromatic ring and the heteroatoms form intramolecular hydrogen bonds, increasing the decomposition temperature. The C-D bond energy is higher than that of C-H, which can improve the antioxidant efficiency.

[0025] The synergistic effect of the formulation of the hydrolysis-resistant reinforced high-temperature nylon composite material of the present invention is manifested as follows: The polyisobutene optimizes the dispersion and migration efficiency of the antioxidant in the nylon resin matrix through molecular chain entanglement. The hydrolysis-resistant agent and the antioxidant form a hydrogen bond network to synergistically block the hydrolysis reaction chain. The reinforcing material enhances the thermal stability and interfacial binding force of the antioxidant by means of the metal ion coordination effect. Through the synergistic coupling of physical entanglement, chemical bonding, and ionic interaction, the three significantly improve the hydrolysis stability, thermal oxidation resistance, and mechanical strength retention rate of the composite material in high-temperature and high-humidity environments.

[0026] Compared with the prior art, the beneficial effects of the present invention are: 1. Significantly enhanced hydrolysis resistance: Through the synergistic effect of antioxidants and hydrolysis-resistant agents, the hydrolysis reaction chain is effectively blocked, and the performance degradation of materials in high-temperature and high-humidity environments is greatly delayed.

[0027] 2. Optimization of antioxidant and thermal stability: The new antioxidant improves the free radical capture efficiency through molecular structure design (such as conjugated systems, bulky substituents), significantly inhibiting oxidative degradation and yellowing during high-temperature processing and use.

[0028] 3. Synergistic improvement of interfacial bonding and mechanical strength: Enhancing the compatibility improvement between the material and the resin matrix, combined with the gradient cooling process, strengthens the interfacial bonding force, enabling the material to maintain a high mechanical strength retention rate under extreme working conditions. Description of the Drawings

[0029] Figure 1 This is the synthesis route of the antioxidant described in the present invention. Detailed Embodiments

[0030] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0031] Synthesis Example 1 Synthesis of Antioxidant 1: ; First step: Under a nitrogen atmosphere, 20 g of raw material 1, 11.76 g of raw material 2, 12.77 g of anhydrous potassium carbonate, 1.60 g of tetrakis(triphenylphosphine)palladium, and 200 g of a mixed solution composed of toluene, ethanol, and water (volume ratio 2:1:1) are successively added to the reaction system, and the reaction is refluxed at 75 °C for 10 hours. After cooling to room temperature, the mixture is allowed to stand for liquid separation. The aqueous phase is extracted twice with ethyl acetate, and the organic phases are combined, dried by rotary evaporation, and then subjected to column chromatography using a mixture of petroleum ether and ethyl acetate as the eluent, finally obtaining 18.60 g of intermediate 1. [M+H] + m / z: 520.

[0032] Step 2: Under a nitrogen atmosphere, 18.60 g of Intermediate 1, 0.3 g of CuI, 15.72 g of Raw Material 3, 19.05 g of potassium phosphate trihydrate, 0.04 g of pyridine-2-carboxylic acid, and 200 g of DMSO were successively added to the reaction system. The mixture was heated to 85 °C and maintained for 16 h. After cooling to room temperature, the resulting reaction mixture was extracted with ammonia water solution and methyl tert-butyl ether. The organic phase was washed with water five times and then with saturated NaCl solution twice. Finally, the combined organic phases were dried over anhydrous magnesium sulfate, concentrated by rotary evaporation, and subjected to column chromatography using a mixture of petroleum ether and ethyl acetate as the eluent to obtain 21.93 g of Antioxidant 1. [M+H] + m / z: 850.

[0033] For Antioxidant 1 1 HNMR (deuterochloroform) δ 8.38 (d, 1H), 8.19 - 8.08 (m, 5H), 8.06 - 7.99 (m, 1H), 7.58 - 7.34 (m, 6H), 7.29 - 7.22 (m, 5H), 6.57 (d, 2H), 6.32 (s, 2H), 6.22 (t, 1H).

[0034] Synthesis Examples 2 - 6 The antioxidants synthesized in Synthesis Examples 2 - 6 were prepared with reference to the synthesis method of Synthesis Example 1, replacing Raw Material 2 therein, while the rest of Synthesis Example 1 remained the same. The specific structures of Raw Material 2, the structures of the antioxidants, and [M+H] + m / z data are shown in the following table.

[0035]

[0036]

[0037] Example 1

[0038] This example provides a hydrolysis-resistant enhanced high-temperature nylon composite material, which is composed of the following components by mass: nylon resin matrix: 70 parts of poly(decamethylene terephthalate) (PA10T), reinforcing material: 25 parts of mica (average particle size 3 μm), 6 parts of polyisobutylene (molecular weight 1200), hydrolysis-resistant agent: 3 parts of polycarbodiimide, antioxidant (the compound synthesized in Synthesis Example 1) 0.5 part, lubricant: 1.5 parts of calcium stearate.

[0039] Its preparation method includes the following steps: S1. The PA10T resin and mica were dried in a vacuum oven at 120 °C for 5 h, and the water content of mica was measured to be 0.25 wt%. S2. Put the dried material, polyisobutylene, polycarbodiimide, antioxidant (the compound synthesized in Synthesis Example 1), and calcium stearate into a high-speed mixer and mix at a speed of 1000 r / min for 8 minutes; S3. The mixture is melt-extruded through a twin-screw extruder. The temperature of each zone is set as follows: Zone 1: 265 °C, Zone 2: 275 °C, Zone 3: 285 °C, Zone 4: 295 °C, and the die head temperature is 290 °C; The extruded strip is cooled by three-stage gradient water cooling: the first-stage cooling water is 65 °C (staying for 8 s) → the second-stage cooling water is 45 °C (staying for 12 s) → the third-stage cooling water is 25 °C (the length of the water tank is 3 m), and the cooling rate is controlled at 12 °C / min; After pelletizing and drying with hot air at 80 °C for 2 hours, a hydrolytic resistance-enhanced high-temperature nylon composite material with a particle size of 3 mm is obtained.

[0040] Examples 2 - 6 For a hydrolytic resistance-enhanced high-temperature nylon composite material prepared in Examples 2 - 6, its preparation method refers to Example 1, and the antioxidant therein is sequentially replaced with the antioxidants prepared in Synthesis Examples 2 - 6, and the rest is the same as in Example 1.

[0041] Comparative Example 1 For a hydrolytic resistance-enhanced high-temperature nylon composite material, its preparation method refers to Example 1, and the antioxidant therein is replaced with Comparative Compound 1, and the rest is the same as in Example 1.

[0042] Comparative Compound 1: .

[0043] Comparative Example 2 For a hydrolytic resistance-enhanced high-temperature nylon composite material, its preparation method refers to Example 1, and the antioxidant therein is replaced with Comparative Compound 2, and the rest is the same as in Example 1.

[0044] Comparative Compound 2: .

[0045] Comparative Example 3 For a hydrolytic resistance-enhanced high-temperature nylon composite material, its preparation method refers to Example 1, and the antioxidant therein is not added, and the rest is the same as in Example 1.

[0046] Performance Test: Perform tensile strength, flexural strength, and hydrolytic and alcoholysis resistance tests on the hydrolytic resistance-enhanced high-temperature nylon composite materials prepared in the examples and comparative examples. The test methods are as follows. The test equipment for tensile strength and flexural strength is a Zwick Z010 electronic tensile machine: Tensile strength: The test standard is ISO 527-2-2012, the speed is 5 mm / min, and the unit is MPa; Flexural strength: The test standard is ISO-178, the span is 64 mm, the speed is 2 mm / min, and the unit is MPa; Hydrolysis and alcoholysis resistance test (120 °C): Immerse the sample to be tested in a constant-temperature oil bath filled with an ethylene glycol aqueous solution (mass ratio of ethylene glycol to water is 1:1). Heat the constant-temperature oil bath to 120 °C and maintain for 150 h. Then, test the flexural strength of the sample after corrosion, with the unit of MPa; Hydrolysis and alcoholysis resistance test (140 °C): Immerse the sample to be tested in a constant-temperature oil bath filled with an ethylene glycol aqueous solution (mass ratio of ethylene glycol to water is 1:1). Heat the constant-temperature oil bath to 140 °C and maintain for 150 h. Then, test the flexural strength of the sample after corrosion, with the unit of MPa; Yellowing resistance performance (170 °C): Test the change in color difference (△E) of the sample to be tested before and after baking at 170 °C for 24 h in an oven. The test instrument is a HunterLab UltraScan PRO colorimeter purchased from Beijing Jinli Tongjian Environmental Technology Co., Ltd.

[0047] The test results are shown in the following table, as follows:

[0048] The examples show significant advantages over the comparative examples in terms of mechanical strength, hydrolysis resistance, and anti-yellowing performance. With the optimization of the substituents in the antioxidant molecular structure, the high-temperature hydrolysis stability and anti-aging ability of the examples are gradually improved, the retention rate of flexural strength under extreme humid and hot conditions is higher, and the color change degree of the material is significantly reduced. Due to the structural defects or absence of antioxidants in the comparative examples, the mechanical properties deteriorate more severely, especially the material strength drops significantly in a high-temperature hydrolysis environment, and the yellowing phenomenon is prominent. In addition, the synergistic effect of the hydrolysis inhibitor and antioxidant effectively inhibits the hydrolysis chain reaction in the examples, while the enhanced interfacial bonding of the material further delays the performance degradation, forming a multi-dimensional protection effect.

[0049] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydrolysis-resistant reinforced high-temperature nylon composite material, characterized in that, It is prepared from components with the following mass ratios: 50 - 85 parts of nylon resin matrix, 10 - 40 parts of reinforcing material, 4 - 8 parts of polyisobutene, 0.5 - 8 parts of hydrolysis-resistant agent, 0.1 - 2 parts of antioxidant, and 0.2 - 3 parts of lubricant; The antioxidant has the structure shown in Formula 1: Formula 1; D represents deuterium; Z1 is selected from: O, S, N(R2), C(CH3)2; R1 is selected from: H, methyl, tert-butyl, phenyl, methoxy; R2 is selected from: H, tert-butyl, phenyl.

2. The hydrolysis-resistant enhanced high-temperature nylon composite material according to claim 1, characterized in that, The nylon resin matrix is selected from at least one of polyhexamethylene terephthalamide, polynonamethylene terephthalamide, and polydecamethylene terephthalamide.

3. A hydrolysis-resistant reinforced high-temperature nylon composite material according to claim 1, wherein The reinforcing material is an inorganic mineral filler, selected from at least one of calcium carbonate, talcum powder, and mica, with an average particle size of 1 - 5 μm.

4. The hydrolytic resistance enhanced high-temperature nylon composite material according to claim 1, characterized in that, The lubricant is selected from at least one of calcium stearate, zinc stearate, and paraffin.

5. The hydrolysis-resistant enhanced high-temperature nylon composite material according to claim 1, wherein The hydrolysis-resistant agent is at least one of polycarbodiimide and pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

6. The hydrolytic resistance enhanced high-temperature nylon composite material according to claim 1, characterized in that The antioxidant is any one of the compounds shown by the following structures: .

7. A method for preparing a hydrolysis-resistant enhanced high-temperature nylon composite material according to any one of claims 1-6, characterized in that, It includes the following steps: S1. Dry the nylon resin matrix and the reinforcing material at 110 - 130 °C for 4 - 6 hours to obtain a dried material; S2. Mix the dried material with the polyisobutene, hydrolysis-resistant agent, antioxidant, and lubricant at 800 - 1200 r / min for 5 - 10 minutes to obtain a mixed material; S3. Add the mixed material into a twin-screw extruder, melt and extrude at 260 - 300 °C, and after water cooling, pelletizing, and drying, obtain a hydrolysis-resistant reinforced high-temperature nylon composite material.

8. The preparation method of a hydrolysis-resistant enhanced high-temperature nylon composite material according to claim 7, characterized in that, The temperature of the twin-screw extruder is controlled in zones: Zone 1 at 260 - 270 °C, Zone 2 at 270 - 280 °C, Zone 3 at 280 - 290 °C, Zone 4 at 290 - 300 °C, and the die head temperature is controlled at 285 - 295 °C.

9. The preparation method of a hydrolysis-resistant enhanced high-temperature nylon composite material according to claim 7, characterized in that, The water content of the reinforcing material after drying is ≤ 0.3 wt%.

10. The preparation method of a hydrolysis-resistant enhanced high-temperature nylon composite material according to claim 7, characterized in that, The water cooling adopts a gradient cooling process, specifically: the temperature of the first-stage cooling water is 60 - 70 °C, the temperature of the second-stage cooling water is 40 - 50 °C, the temperature of the third-stage cooling water is 20 - 30 °C, and the cooling rate does not exceed 15 °C / min.

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