High-strength nylon for humanoid robot and preparation method of high-strength nylon

Abstract

The invention discloses high-strength nylon for a humanoid robot and a preparation method of the high-strength nylon. According to the composite material, MXD6 nylon and PA66 nylon are used as a composite matrix, chopped carbon fibers are used as a main reinforcement body, and a flexibilizer, an antioxidant, a lubricant and a nucleating agent are added. The preparation method comprises the following steps: performing vacuum drying on the raw materials, putting the dried raw materials into a double-screw extruder according to a specific ratio, and performing melt blending and granulation at a precisely controlled temperature interval (240-285 DEG C) and a screw rotating speed; and drying the obtained particles, and molding the dried particles into the required structural member through an injection molding machine under specific process parameters. Through synergistic interaction of MXD6 and PA66 and optimization of a processing technology, the composite material with high strength, high rigidity, high fatigue resistance, excellent impact toughness and extremely low water absorption is successfully prepared, and the technical problem that performance of an existing humanoid robot structural part material is unbalanced is perfectly solved; and the motion precision, the load capacity and the long-term reliability of the robot are obviously improved.

Description

Technical Field

[0001] This invention belongs to the field of novel nylon composite materials, and specifically discloses a high-strength nylon for humanoid robots and its preparation method. Background Technology

[0002] Nylon engineering plastics are widely used in industrial manufacturing due to their excellent mechanical strength, wear resistance, and self-lubricating properties. Humanoid robots, as the pinnacle of high-end equipment manufacturing, place extremely stringent demands on the lightweight, high strength, fatigue resistance, and dimensional stability of their core structural components such as joints, links, and skeletons. However, existing general-purpose nylon materials (such as PA66 and PA6) exhibit significant performance shortcomings when applied to humanoid robots: First, their high water absorption leads to significant dimensional changes in humid environments, affecting motion accuracy; second, their resistance to long-term cyclic loads (fatigue resistance) is insufficient, making them prone to cracking or even breakage during high-frequency, high-load movements, raising questions about reliability; third, the toughness of conventional reinforced nylon materials often decreases with increasing strength, making it difficult to balance structural load-bearing and impact resistance requirements.

[0003] Currently, to address the aforementioned issues, the industry commonly employs short fiber reinforcement or the addition of rigid fillers to enhance the strength and modulus of nylon materials. However, these methods often lead to increased material brittleness and deteriorated impact performance. Furthermore, under repeated stress, the filler-matrix interface is prone to becoming a fatigue crack initiation point, failing to meet the lifespan requirements of millions or even tens of millions of reciprocating motions for robot joints. On the other hand, although some research has attempted to utilize MXD6 nylon due to its excellent gas barrier properties and low water absorption, its crystallization rate is relatively slow, and the rigidity and heat distortion temperature of pure MXD6 resin are insufficient to support heavy-duty structural components.

[0004] Furthermore, existing composite material preparation processes have limitations: poor compatibility when blending multiple nylon resins leads to phase separation and uneven performance; reinforcing fibers are difficult to disperse uniformly in high-viscosity melts, easily forming agglomerates and becoming stress concentration points; the complex flow and temperature fields during injection molding can easily cause internal stress and orientation in the product, affecting dimensional accuracy and the uniformity of mechanical properties. Therefore, developing a special nylon composite material that comprehensively combines high strength, high rigidity, high fatigue resistance, low water absorption, and excellent dimensional stability, along with a precise and controllable preparation process, has become a key technical challenge that urgently needs to be solved to promote the development of humanoid robots towards high performance and high reliability. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention discloses a high-strength nylon for humanoid robots and its preparation method.

[0006] To achieve the above objectives, the present invention includes the following technical solutions.

[0007] A method for preparing high-strength nylon for use in humanoid robots includes the following steps: (1) Pre-drying of raw materials: The following raw materials, by weight, are vacuum dried at 80-100℃ for 6-8 hours to reduce the moisture content to below 0.05%: 50-70 parts of MXD6 nylon resin; 10-20 parts of PA66 nylon resin; 15-25 parts of short-cut carbon fiber; 3-8 parts toughening agent; Antioxidant 0.3-1.0 parts; 0.5-1.5 parts lubricant; Nucleating agent 0.2-0.8 parts; (2) Melt blending: All the dried raw materials are added to a twin-screw extruder and melt blended, extruded, cooled, drawn and pelletized to obtain nylon composite material particles; wherein, the processing temperature of the twin-screw extruder is: Zone 1 240-250℃, Zone 2 250-260℃, Zone 3 260-270℃, Zone 4 265-275℃, and the die head 270-275℃; the screw speed is 300-400r / min; (3) Injection molding: After drying the obtained nylon composite material particles at 100-120℃ for 4-6 hours, place them in an injection molding machine and injection mold them into humanoid robot structural parts under the process conditions of barrel temperature 265-285℃, injection pressure 70-100MPa, and mold temperature 80-100℃.

[0008] Furthermore, in the above preparation method, the intrinsic viscosity of the MXD6 nylon resin is 0.9-1.2 dL / g, and the melting point is 243-247℃.

[0009] Furthermore, in the above preparation method, the toughening agent is maleic anhydride-grafted polyolefin elastomer (POE-g-MAH) or maleic anhydride-grafted ethylene-acrylate copolymer.

[0010] Furthermore, in the above preparation method, the nucleating agent is one of sodium phenylphosphite, talc, or silicon dioxide.

[0011] Furthermore, in the above preparation method, the antioxidant is a compound of hindered phenolic antioxidant 1010 and phosphite antioxidant 168 in a mass ratio of 1:1 to 1:2; the lubricant is pentaerythritol stearate or ethylene bis-stearamide.

[0012] This invention discloses a high-strength nylon composite material, which is prepared by any of the above-described preparation methods. The composite material is a multiphase system with MXD6 nylon resin and PA66 nylon resin as the matrix and short-cut carbon fiber as the reinforcing phase.

[0013] Furthermore, the aforementioned high-strength nylon composite material has a tensile strength ≥180 MPa, a flexural strength ≥250 MPa, a flexural modulus ≥11000 MPa, and a cantilever beam notched impact strength ≥10 kJ / m. 2 Heat distortion temperature ≥200℃.

[0014] Furthermore, the aforementioned high-strength nylon composite material exhibits a static tensile strength retention rate of ≥70% under 10^7 cyclic loading.

[0015] The present invention also discloses the application of the above-mentioned high-strength nylon composite material in humanoid robots, for the preparation of structural components of the robot, the structural components including joint bearing seats, leg support skeletons, arm links or torso load-bearing frames.

[0016] Furthermore, in the above application, after the structural component is equilibrated at 23°C and 50% humidity, its water absorption rate is less than 2.5%, and its dimensional change rate after water absorption is less than 0.5%.

[0017] Compared with the prior art, the present invention has the following outstanding advantages: 1. Excellent comprehensive mechanical properties: MXD6 resin provides low water absorption and good toughness, PA66 resin contributes high rigidity and heat resistance, and short-cut carbon fiber greatly improves strength and modulus. The synergistic effect of the three makes the material achieve the best balance between strength, rigidity and toughness, far exceeding that of single resin or ordinary reinforcement system.

[0018] 2. Excellent dimensional stability: Thanks to the inherent low water absorption of MXD6 nylon, the material has an extremely low water absorption rate in humid environments and minimal dimensional changes, effectively ensuring the dimensional stability and motion accuracy of high-precision structural components for humanoid robots made from it in complex environments.

[0019] 3. High durability and reliability: The material exhibits excellent long-term cyclic load resistance and creep resistance, enabling it to withstand high-frequency, high-load reciprocating motion of humanoid robots. It has strong fatigue resistance and damage resistance, and a long service life, meeting the stringent requirements of robots for high reliability of core structural components.

[0020] 4. Good process adaptability: The preparation process parameters designed in this invention are scientific and reasonable, which can ensure that the components are evenly dispersed and the interface is well bonded. Moreover, the injection molding processing window is wide, which makes it easy to achieve stable molding and mass production of complex structural parts. Attached Figure Description

[0021] Figure 1 Comparison of basic mechanical property test results (tensile strength (MPa)); Figure 2 Comparison of basic mechanical property test results (tensile modulus (GPa)); Figure 3 Comparison of basic mechanical property test results (elongation at break (%)); Figure 4 Comparison of basic mechanical property test results (flexural strength (MPa)); Figure 5 Comparison of basic mechanical property test results (flexural modulus (GPa)); Figure 6 Comparative test results of basic mechanical properties (notched impact strength (kJ / m)) 2 A comparison of )). Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The following is the raw material list for the examples.

[0024] Table 1: Raw Material List Example 1 A high-strength nylon composite material for structural components of humanoid robots, made from the following raw materials in parts by weight: 50 parts of MXD6 nylon resin (intrinsic viscosity 1.0 dL / g); 20 parts of PA66 nylon resin; Short-cut carbon fiber (3mm in length), 25 parts; 3 parts of maleic anhydride-grafted polyolefin elastomer (POE-g-MAH); Antioxidant 1010, 0.2 parts; Antioxidant 168, 0.2 parts; 0.5 parts pentaerythritol stearate; Sodium phenylphosphite 0.2 parts; Its preparation method includes the following steps: (1) Raw material pre-drying: All raw materials were vacuum dried at 90℃ for 8 hours to reduce the moisture content to below 0.05%; (2) Melt blending: All the dried raw materials are added to a twin-screw extruder and melt blended, extruded, cooled, drawn and pelletized to obtain nylon composite material particles; wherein, the processing temperature of the twin-screw extruder is set as follows: Zone 1 245℃, Zone 2 255℃, Zone 3 265℃, Zone 4 270℃, and die head 275℃; the screw speed is 350 r / min; (3) Injection molding: After drying the obtained nylon composite material particles at 110°C for 5 hours, they are placed in an injection molding machine and injected into standard test strips and simulated structural parts under the process conditions of barrel temperature 270°C, injection pressure 80MPa and mold temperature 90°C.

[0025] Example 2 A high-strength nylon composite material for structural components of humanoid robots, made from the following raw materials in parts by weight: 60 parts of MXD6 nylon resin (intrinsic viscosity 1.1 dL / g); 15 parts of PA66 nylon resin; Short-cut carbon fiber (4.5mm in length), 20 parts; 5 parts of maleic anhydride-grafted ethylene-acrylate copolymer; Antioxidant 1010, 0.3 parts; Antioxidant 168, 0.4 parts; 1.0 part of ethylene bis-stearamide; Talc powder (particle size 2μm) 0.5 parts; Its preparation method includes the following steps: (1) Raw material pre-drying: All raw materials were vacuum dried at 95℃ for 7 hours to reduce the moisture content to below 0.05%; (2) Melt blending: All the dried raw materials are added to a twin-screw extruder and melt blended, extruded, cooled, drawn and pelletized to obtain nylon composite material particles; wherein, the processing temperature of the twin-screw extruder is set as follows: Zone 1 250℃, Zone 2 260℃, Zone 3 270℃, Zone 4 272℃, and the die head 272℃; the screw speed is 380 r / min; (3) Injection molding: After drying the obtained nylon composite material particles at 105°C for 5.5 hours, they are placed in an injection molding machine and injected into standard test strips and simulated structural parts under the process conditions of barrel temperature 275°C, injection pressure 90MPa and mold temperature 95°C.

[0026] Example 3 A high-strength nylon composite material for structural components of humanoid robots, made from the following raw materials in parts by weight: 70 parts of MXD6 nylon resin (intrinsic viscosity 1.2 dL / g); 10 parts of PA66 nylon resin; 15 portions of short-cut carbon fiber (6mm in length); Maleic anhydride-grafted polyolefin elastomer (POE-g-MAH) 8 parts; Antioxidant 1010, 0.4 parts; Antioxidant 168, 0.6 parts; 1.5 parts pentaerythritol stearate; 0.8 parts of silica (nanoscale); Its preparation method includes the following steps: (1) Raw material pre-drying: All raw materials were vacuum dried at 100℃ for 6 hours to reduce the moisture content to below 0.05%; (2) Melt blending: All the dried raw materials are added to a twin-screw extruder and melt blended, extruded, cooled, drawn and pelletized to obtain nylon composite material particles; wherein, the processing temperature of the twin-screw extruder is set as follows: Zone 1 248℃, Zone 2 258℃, Zone 3 268℃, Zone 4 274℃, and die head 278℃; the screw speed is 320 r / min; (3) Injection molding: After drying the obtained nylon composite material particles at 115°C for 4.5 hours, they are placed in an injection molding machine and injected into standard test strips and simulated structural parts under the process conditions of barrel temperature 280°C, injection pressure 75MPa and mold temperature 85°C.

[0027] Comparative Example 1 A nylon composite material, whose raw materials and processing methods are basically the same as those in Example 2, with the only difference being: Instead of using MXD6 nylon resin, 60 parts by weight are replaced entirely by PA66 nylon resin, meaning the total PA66 content is 75 parts.

[0028] Comparative Example 2 A nylon composite material, whose raw materials and processing methods are basically the same as those in Example 2, with the only difference being: Instead of using chopped carbon fiber, 20 parts of its weight are replaced by an equal amount of chopped glass fiber (4.5 mm in length).

[0029] Comparative Example 3 A nylon composite material, whose raw materials and processing methods are basically the same as those in Example 2, with the only difference being: Without adding toughening agent (maleic anhydride-grafted ethylene-acrylate copolymer), 5 parts by weight are deducted from PA66 nylon resin, meaning the PA66 content is 10 parts.

[0030] Comparative Example 4 A nylon composite material with the same raw material ratio as in Example 2.

[0031] The preparation method differs from that in Example 2 in that: In step (2) melt blending, the screw speed of the twin-screw extruder is reduced to 200 r / min.

[0032] Comparative Example 5 A nylon composite material, whose raw materials and processing methods are basically the same as those in Example 2, with the only difference being: PA66 nylon resin is not used; its 15 parts by weight are entirely replaced by MXD6 nylon resin, meaning the total MXD6 content is 75 parts.

[0033] Test Example 1 Basic mechanical property comparison test Objective: To verify the comprehensive advantages of the composite material of the present invention in terms of strength, stiffness and toughness.

[0034] method: Sample preparation: The materials prepared in Examples 1-3 and Comparative Examples 1-5 were injection molded into standard ISO tensile specimens (Type 1A) and impact specimens (80mm x 10mm x 4mm). Five valid samples were obtained from each group, and the average value was taken.

[0035] Testing standards: Tensile properties: Tested according to ISO 527-1 / -2 on a universal testing machine (model: Instron 5967) at a tensile rate of 5 mm / min, and the tensile strength, tensile modulus and elongation at break were recorded.

[0036] Bending performance: Perform a three-point bending test according to ISO 178 standard, with a span of 64 mm and a test rate of 2 mm / min, and record the bending strength and bending modulus.

[0037] Impact performance: The notched specimen (Type A notch) was impacted using a cantilever beam impact testing machine (model: Ceast 9050) according to ISO 180 standard, and the notch impact strength was recorded.

[0038] The results are shown in Table 2 and Figure 1-6 .

[0039] Table 2: Comparison Test Results of Basic Mechanical Properties Conclusion: The samples in Examples 1-3 of this invention exhibited the best overall mechanical properties. The MXD6 / PA66 / carbon fiber system (examples) significantly outperformed the pure PA66 system (Comparative Example 1) and the glass fiber reinforced system (Comparative Example 2) in terms of strength, modulus, and toughness. Comparative Example 3 (without toughening agent) showed a sharp decrease in impact strength, demonstrating the crucial role of the toughening agent in ensuring material toughness. Comparative Example 4 (low-speed mixing) showed a comprehensive performance decline due to uneven filler dispersion. Comparative Example 5 (without PA66), while exhibiting good toughness, lacked sufficient rigidity and strength, failing to meet the requirements for structural components.

[0040] Test Example 2 Dimensional and performance stability testing under humid and hot conditions Objective: To verify the dimensional stability and performance retention of the material under high humidity and high temperature conditions, simulating the long-term operating conditions of a humanoid robot.

[0041] method: Sample preparation: The samples of Example 2, Comparative Example 1 (pure PA66) and Comparative Example 5 (pure MXD6) were placed in a constant temperature and humidity chamber.

[0042] Test conditions: Conditioning was performed at 70°C and 62% relative humidity, in accordance with ISO 62 (water absorption test) and ISO 1110 (accelerated moisture conditioning). Samples were taken after 0h, 24h, 168h (1 week), and 672h (4 weeks).

[0043] Test metrics: Weight and dimensional changes: Measure the water absorption rate of the sample and the rate of dimensional change along the flow direction and perpendicular to the flow direction.

[0044] Performance retention rate: After the moisture-absorbing sample is dried, its tensile strength and flexural strength are tested immediately, and the retention rate (%) relative to its initial dry strength is calculated.

[0045] The results are shown in Table 3.

[0046] Table 3: Performance Comparison After 672 hours of Damp Heat Aging Conclusion: The material of this invention (Example 2), due to the low water absorption of MXD6, is significantly superior to conventional PA66 (Comparative Example 1). Its water absorption rate and dimensional change rate are both much lower than those of Comparative Example 1, thus maintaining extremely high performance stability in humid and hot environments. Although pure MXD6 (Comparative Example 5) has even lower water absorption, its overall mechanical properties (see Test Example 1) are insufficient to meet the requirements. This invention successfully balances the dimensional stability resulting from low water absorption with excellent mechanical properties.

[0047] Test Example 3 Fatigue resistance test Objective: To verify the durability of the material under long-term alternating loads and evaluate its reliability for use in high-frequency motion joint components.

[0048] method: Sample preparation: Injection-molded specimens from Example 2, Comparative Example 1 (pure PA66+CF), Comparative Example 2 (PA66 / MXD6+GF), and Comparative Example 3 (without toughening agent) were used for testing.

[0049] Test standard: Perform tensile-tensile fatigue test according to ISO 13003-1.

[0050] Test conditions: Stress ratio R = 0.1, frequency 5 Hz, conducted at room temperature (23±2℃). Two stress levels were set: high stress (approximately 50% of the tensile strength of each material) and low stress (approximately 35% of the tensile strength of each material). The number of cycles to fracture (fatigue life) for each specimen under different stress levels was recorded, and the number of specimens that did not fracture after 10^7 cycles was observed.

[0051] The results are shown in Table 4.

[0052] Table 4: Fatigue life under different stress levels Conclusion: The material of this invention (Example 2) exhibited the longest average fatigue life under high stress levels, exceeding that of the comparative examples by more than 87%. In long-term cyclic testing at low stress levels, all samples from Example 2 successfully passed 10 million cycles without failure, demonstrating extremely high reliability. Comparative Example 3 (without toughening agent), due to its brittleness, showed the worst fatigue performance. This indicates that the formulation and process of this invention significantly improve the durability of the material under dynamic loads.

[0053] Test Example 4 Heat distortion temperature (HDT) test Objective: To verify the material's resistance to deformation at high temperatures and to evaluate its suitability for use in structural components near motors where temperature rise may occur.

[0054] method: Sample preparation: The injection-molded specimens of Example 2, Comparative Example 1, and Comparative Example 5 were tested.

[0055] Test Standard: Tested according to ISO 75-1 / -2 standard using a heat deflection temperature testing machine (model: Ceast HDT 3VICAT) under a bending load of 1.82 MPa. The heating rate was 120℃ / h. The temperature at which the specimen reached the standard deflection was recorded, i.e., the heat deflection temperature (HDT).

[0056] The results are shown in Table 5.

[0057] Table 5: Test results of heat distortion temperature (HDT @ 1.82 MPa) Conclusion: The heat distortion temperature (208°C) of the material of this invention (Example 2) is much higher than its melting point, fully meeting the usage requirements of humanoid robots in normal environments and under motor heating conditions. Although Comparative Example 1 (pure PA66) has a higher HDT due to its higher crystallinity, its high water absorption rate leads to dimensional instability, which is a fatal flaw (see Test Example 2). Comparative Example 5 (pure MXD6) has a relatively low HDT. This invention achieves optimal overall performance balance by utilizing the synergistic effect of MXD6 / PA66, ensuring low water absorption while obtaining sufficiently high heat resistance.

[0058] Test Example 5 Cyclic impact toughness test Objective: To evaluate the energy absorption capacity and crack propagation resistance of materials under multiple impact loads, simulating the working conditions of joint components subjected to accidental collisions or frequent start-stop cycles.

[0059] method: Sample preparation: Notched impact specimens from Example 2 and Comparative Example 1 were used.

[0060] Test Method: Following the Charpy impact test method, a pendulum impact testing machine was used. Multiple consecutive impacts were applied to the same notch location on a single specimen, with each impact energy set to 50% of its initial impact strength (see Test Example 1). The impact energy absorbed by the specimen after each impact was recorded until the specimen completely fractured. The number of impacts the specimen could withstand before fracture was counted.

[0061] The results are shown in Table 6.

[0062] Table 6: Results of multiple impact tests (Initial impact energy: Example 2 6.4 J, Comparative Example 1 4.1 J) Conclusion: The material of this invention (Example 2) can withstand more consecutive impacts before fracturing, and in the final impact, it can still absorb most of the energy (retaining 80% of its initial capacity), indicating that it has high damage tolerance, slow crack propagation rate, and excellent toughness. In contrast, Comparative Example 1 (pure PA66) fractured after fewer impacts, and its remaining energy absorption capacity decreased more significantly. This proves that the material of this invention can better withstand the repeated impact loads that humanoid robots may encounter in complex working environments, and has higher reliability.

[0063] Test Case Summary: The above test examples verify the excellent performance of the high-strength nylon described in this invention. The data is summarized as follows: 1. Basic mechanical properties: Tensile strength ≥185 MPa, flexural strength ≥255 MPa, flexural modulus ≥10.8 GPa, notched impact strength ≥11.5 kJ / m 2 The heat distortion temperature (1.82MPa) is ≥205℃, and its overall performance is superior to that of the comparative example.

[0064] 2. Environmental stability: After being treated in a 70℃ / 62%RH environment for 672 hours, the water absorption rate is only 0.75%, the dimensional change rate is only 0.12%, and the tensile and flexural strength retention rates are both higher than 94.5%, which is far superior to pure PA66 material (water absorption rate 1.65%, strength retention rate about 81%).

[0065] 3. Dynamic Durability: In fatigue testing, all sample examples passed 10 million cycles under 67 MPa stress without fracture; in multiple impact tests, they withstood an average of 5.8 impacts, with a final impact energy absorption retention rate as high as 80%, significantly better than comparative materials. All quantitative data fully demonstrate that the material of this invention possesses superior performance to meet the high-end applications of humanoid robots. The above are merely a few preferred embodiments of the present invention, described in a relatively specific and detailed manner, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for preparing high-strength nylon for use in humanoid robots, characterized in that, Includes the following steps: (1) Pre-drying of raw materials: The following raw materials are vacuum dried at 80-100℃ for 6-8 hours according to the following parts by weight, so that the moisture content is less than 0.05%: 50-70 parts of MXD6 nylon resin; 10-20 parts of PA66 nylon resin; 15-25 parts of short-cut carbon fiber; 3-8 parts toughening agent; Antioxidant 0.3-1.0 parts; 0.5-1.5 parts lubricant; Nucleating agent 0.2-0.8 parts; (2) Melt blending: All the dried raw materials are added to a twin-screw extruder and melt blended, extruded, cooled, drawn and pelletized to obtain nylon composite material particles; wherein, the processing temperature of the twin-screw extruder is: Zone 1 240-250℃, Zone 2 250-260℃, Zone 3 260-270℃, Zone 4 265-275℃, and the die head 270-275℃; the screw speed is 300-400r / min; (3) Injection molding: After drying the obtained nylon composite material particles at 100-120℃ for 4-6 hours, place them in an injection molding machine and injection mold them into humanoid robot structural parts under the process conditions of barrel temperature 265-285℃, injection pressure 70-100MPa, and mold temperature 80-100℃.

2. The preparation method according to claim 1, characterized in that: The intrinsic viscosity of the MXD6 nylon resin is 0.9-1.2 dL / g, and the melting point is 243-247℃.

3. The preparation method according to claim 1, characterized in that: The toughening agent is maleic anhydride-grafted polyolefin elastomer (POE-g-MAH) or maleic anhydride-grafted ethylene-acrylate copolymer.

4. The preparation method according to claim 1, characterized in that: The nucleating agent is one of sodium phenylphosphite, talc, or silicon dioxide.

5. The preparation method according to claim 1, characterized in that: The antioxidant is a compound of hindered phenolic antioxidant 1010 and phosphite antioxidant 168 in a mass ratio of 1:1 to 1:2; the lubricant is pentaerythritol stearate or ethylene bis-stearamide.

6. A high-strength nylon composite material, characterized in that: The composite material is prepared by the preparation method according to any one of claims 1-5, and is a multiphase system with MXD6 nylon resin and PA66 nylon resin as the matrix and short-cut carbon fiber as the reinforcing phase.

7. The high-strength nylon composite material according to claim 6, characterized in that: Its tensile strength ≥180 MPa, flexural strength ≥250 MPa, flexural modulus ≥11000 MPa, and cantilever beam notched impact strength ≥10 kJ / m 2 Heat distortion temperature ≥200℃.

8. The high-strength nylon composite material according to claim 7, characterized in that: Static tensile strength with a fatigue strength retention rate of ≥70% under 10^7 cycles of loading.

9. The application of the high-strength nylon composite material as described in claim 7 in humanoid robots, characterized in that: Structural components used to manufacture robots include joint bearing seats, leg support frames, arm links, or torso load-bearing frames.

10. The application according to claim 9, characterized in that: After the structural component is equilibrated at 23°C and 50% humidity, its water absorption rate is less than 2.5%, and its dimensional change rate after water absorption is less than 0.5%.

Images