Rubber material for humanoid robot protection application and preparation method thereof

Abstract

The invention relates to the technical field of rubber materials, in particular to a rubber material for humanoid robot protection application and a preparation method thereof.The rubber material takes ethylene propylene diene monomer, hydrogenated nitrile rubber and fluororubber as matrixes, modified nano silicon dioxide, carbon nanotubes and other fillers are compounded, and flame-retardant, antistatic and other functional auxiliaries are added; the uniform performance of the material is ensured through the processes of ultrasonic-assisted dispersion, segmented gradient vulcanization and the like; the protection assembly is of a multi-layer composite structure composed of a base cloth enhancement layer, a buffer layer and a functional surface layer, interlayer chemical bonding is achieved through plasma treatment, and the functional surface layer obtains the self-lubricating and lyophobic characteristics through laser micro-texture treatment. The tensile strength of the material is larger than or equal to 18 MPa, the flame retardance reaches the UL94V-0 level, the surface resistivity is smaller than or equal to 1 * 10 < 9 > ohm, and the material has excellent mechanical performance, environment tolerance and multifunctional integration and can be widely applied to humanoid robot protection in the fields of industry, medical treatment and the like, the reliability of a robot is effectively improved, and the service life of the robot is effectively prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of rubber materials, and in particular to a rubber material for humanoid robot protection applications and a preparation method thereof. Background Art

[0002] With the rapid development of artificial intelligence and intelligent manufacturing technologies, humanoid robots are increasingly used in industrial production, medical services, special operations and other fields. During actual operation, robots need to frequently come into contact with complex environments, such as oil pollution, high temperature, and mechanical collisions in industrial scenes, chemical reagents and bacterial contamination in medical scenes, and extreme temperatures and highly corrosive media in special operations, which puts extremely high demands on robot protective materials.

[0003] Rubber materials are a common choice for robot protective components due to their good flexibility, wear resistance, and processability. However, existing rubber protective materials have many limitations: Single performance: Traditional rubbers struggle to simultaneously meet multiple functional requirements, including high-temperature resistance, chemical corrosion resistance, flame retardancy, and antistatic properties. For example, while ordinary EPDM rubber offers good weather resistance, it lacks high-temperature and oil resistance. Fluororubber, while offering excellent high-temperature resistance, is expensive and difficult to process, making its single use inadequate for complex working conditions. Insufficient mechanical properties: When the robot joints move frequently or are subjected to external impact, conventional rubber materials have low tensile strength and tear strength, which can easily lead to damage and breakage, resulting in protection failure and shortening the robot's service life; Outdated preparation technology: The existing mixing process has poor dispersion effect on nanofillers, which is prone to agglomeration and affects the uniformity of material properties. The vulcanization process lacks precise control and the cross-linking structure is unstable, resulting in large fluctuations in product quality and difficulty meeting the needs of large-scale industrial production. Design defects of protective structure: Traditional protective components mostly adopt single-layer or simple composite structures, with weak interlayer bonding and easy stratification; the surface performance is single and cannot achieve self-lubrication, self-cleaning and other functions, which increases the robot's operating energy consumption and maintenance costs.

[0004] Therefore, in order to solve the above problems, a rubber material for humanoid robot protection application and a preparation method thereof are proposed. Summary of the Invention

[0005] The object of the present invention is to provide a rubber material for humanoid robot protection applications and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: A rubber material for humanoid robot protection applications, comprising the following components in parts by weight: 40-60 parts of EPDM, 20-35 parts of hydrogenated nitrile rubber HNBR, 10-20 parts of fluororubber FKM, 15-25 parts of modified nano-silica, 3-8 parts of carbon nanotubes, 2-5 parts of zinc oxide, 1-3 parts of stearic acid, 1-4 parts of antioxidant RD, 0.5-2 parts of di-tert-butyl peroxide BIPB, 5-10 parts of plasticizer dioctyl adipate DOA, 8-15 parts of flame retardant decabromodiphenyl ethane, 2-5 parts of antistatic agent quaternary ammonium salt compound; Modified nano-silica is nano-scale silica surface-modified with silane coupling agent KH-570, with a particle size of 20-50nm; The carbon nanotubes are multi-walled carbon nanotubes with an aspect ratio of ≥1000, and the surface is plasma treated to enhance dispersion.

[0007] As a preferred solution, the Mooney viscosity of EPDM rubber is 60-80, and the ethylene content is 50-60wt%; the acrylonitrile content of hydrogenated nitrile rubber is 34-38%, and the degree of hydrogenation is ≥95%; the fluororubber is a vinylidene fluoride-hexafluoropropylene copolymer, and the fluorine content is ≥65%.

[0008] As a preferred embodiment, the flame retardant further comprises a compound system of zinc borate and magnesium hydroxide in a mass ratio of 1:2, with a total addition amount of 5-10 parts; the antistatic agent is octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate, with a surface resistivity of ≤1×10 9 Ω.

[0009] As a preferred embodiment, functional additives are also included, including by weight: 0.5-2 parts of graphene, 0.3-1 parts of nano-cerium oxide, and 3-6 parts of polytetrafluoroethylene micropowder PTFE; Graphene is a product prepared by redox method with a monolayer rate of ≥95% and a specific surface area of ≥800m² / g.

[0010] A method for preparing a rubber material for humanoid robot protection applications comprises the following steps: S1. Pre-mixing: Mix EPDM rubber, hydrogenated nitrile rubber and fluororubber in an internal mixer at 80-100°C for 5-8 minutes at a speed of 40-60 r / min; S2. Filler dispersion: Add modified nano-silica, carbon nanotubes, zinc oxide, and stearic acid, heat to 110-120°C and mix for 10-15 minutes; S3. Adding functional additives: Add antioxidant RD, plasticizer DOA, flame retardant, and antistatic agent in sequence, and mix at 60-70°C for 5-8 minutes; S4. Dynamic vulcanization: Add vulcanizing agent BIPB and perform dynamic vulcanization in a twin-screw extruder at 160-180°C, with a screw speed of 200-300 r / min and a residence time of 2-4 minutes; S5. Post-treatment: After calendering, a segmented gradient vulcanization process is adopted, with the first stage at 160℃×10min, the second stage at 180℃×8min, and the third stage at 200℃×5min, and the pressure is 15-20MPa.

[0011] As a preferred solution, an ultrasonic-assisted dispersion process is adopted in step S2, with a frequency of 20-40 kHz, a power of 500-800 W, and a processing time of 20-30 minutes.

[0012] As a preferred solution, in step S4, functional additives are added before dynamic vulcanization and are uniformly injected into the rubber compound through microporous injection technology.

[0013] As a preferred solution, the rubber material is used to prepare the humanoid robot protective component, which includes a multi-layer composite structure, from the inside to the outside: The base fabric reinforcement layer is aramid fiber braid with a thickness of 0.2-0.5mm; Buffer layer, rubber material, thickness 1-2mm; Functional surface layer, rubber material containing functional additives, thickness 0.5-1mm; Chemical bonding is achieved between the base fabric reinforcement layer, buffer layer and functional surface layer through plasma treatment, and the interface peel strength is ≥15N / mm.

[0014] As a preferred solution, the surface of the functional surface layer is treated with laser micro-texturing to form honeycomb grooves with a depth of 50-100 μm, a friction coefficient of ≤0.3, and a contact angle of ≥150°.

[0015] It can be seen from the technical solutions provided by the present invention that the rubber material for humanoid robot protection and the preparation method thereof provided by the present invention have the following beneficial effects: 1. Comprehensive improvement of material performance: Excellent mechanical properties: Through the scientific ratio of EPDM rubber, hydrogenated nitrile rubber and fluororubber, combined with modified nano-silica and carbon nanotube reinforcement system, the rubber material of this invention has a tensile strength of ≥18MPa, elongation at break ≥450%, and tear strength ≥35kN / m. Compared with traditional rubber materials, the tensile strength is increased by more than 50%, which can effectively resist external force impact and wear during robot movement, significantly improving the durability of protective components. Strong environmental adaptability: The introduction of fluororubber gives the material excellent high-temperature resistance (can be used for long periods above 200°C), hydrogenated nitrile rubber ensures oil and chemical corrosion resistance, and EPDM rubber provides excellent weather resistance. At the same time, the material has a temperature resistance range of -40°C to 200°C, and its quality changes little after immersion in media such as engine oil, acids and alkalis. It can adapt to complex environments such as industry, medical care, and special operations, greatly expanding the application scenarios of humanoid robots. High functional integration: The unique flame retardant system enables the material to meet the UL94V-0 flame retardant standard, and the antistatic system controls the surface resistivity to ≤1×10 9 Ω, avoiding electrostatic interference and fire hazards; after adding functional additives, the material also has self-lubricating, heat dissipating, antibacterial and other properties, meeting the multi-dimensional protection needs of robots; 2. Innovative advantages of preparation technology: Precise dispersion and mixing: Temperature gradient control and shear force field optimization in the pre-mixing stage, combined with ultrasonic-assisted dispersion and microporous injection technology, ensure uniform dispersion of nanofillers and avoid agglomeration, thereby improving material performance uniformity by more than 30% and effectively enhancing product quality stability. Efficient vulcanization and molding: Twin-screw extrusion dynamic vulcanization and segmented gradient vulcanization processes precisely control the cross-linking network formation process, shortening the vulcanization time by 20%-30%, while improving the cross-linking density and mechanical properties, reducing production costs and improving production efficiency; Strong quality controllability: Multi-link detection and parameter regulation are set up in the preparation process, such as power curve monitoring during the mixing process, real-time detection and adjustment of mixing quality. Combined with the intermediate product quality certification system, precise control of product quality is achieved, and the defective product rate is reduced to below 5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a schematic flow chart of the steps of a method for preparing a rubber material for humanoid robot protection applications. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0018] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0019] An embodiment of the present invention provides a rubber material for humanoid robot protection applications, comprising the following components in parts by weight: 40-60 parts of EPDM, 20-35 parts of hydrogenated nitrile rubber HNBR, 10-20 parts of fluororubber FKM, 15-25 parts of modified nano-silica, 3-8 parts of carbon nanotubes, 2-5 parts of zinc oxide, 1-3 parts of stearic acid, 1-4 parts of antioxidant RD, 0.5-2 parts of di-tert-butyl peroxide BIPB, 5-10 parts of plasticizer dioctyl adipate DOA, 8-15 parts of flame retardant decabromodiphenyl ethane, 2-5 parts of antistatic agent quaternary ammonium salt compound; Modified nano-silica is nano-scale silica surface-modified with silane coupling agent KH-570, with a particle size of 20-50nm; The carbon nanotubes are multi-walled carbon nanotubes with an aspect ratio of ≥1000, and the surface is plasma treated to enhance dispersion.

[0020] In this embodiment, the Mooney viscosity of the EPDM rubber is 60-80, and the ethylene content is 50-60wt%; the acrylonitrile content of the hydrogenated nitrile rubber is 34-38%, and the degree of hydrogenation is ≥95%; the fluororubber is a vinylidene fluoride-hexafluoropropylene copolymer, and the fluorine content is ≥65%.

[0021] In this embodiment, the flame retardant further comprises a composite system of zinc borate and magnesium hydroxide in a mass ratio of 1:2, with a total addition amount of 5-10 parts; the antistatic agent is octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate, with a surface resistivity of ≤1×10 9 Ω.

[0022] In this embodiment, functional additives are also included, including by weight: 0.5-2 parts of graphene, 0.3-1 parts of nano-cerium oxide, and 3-6 parts of polytetrafluoroethylene micropowder PTFE; Graphene is a product prepared by redox method with a monolayer rate of ≥95% and a specific surface area of ≥800m² / g.

[0023] Furthermore, the rubber material formulation system is explained in detail including: 1. Main rubber system design: The present invention adopts a ternary blend system of ethylene propylene diene monomer (EPDM), hydrogenated nitrile butadiene rubber (HNBR) and fluororubber (FKM), achieving complementary performance through precise proportions: EPDM (40-60 parts): As a base rubber, its high ethylene content (50-60wt%) provides excellent aging resistance and low-temperature elasticity. A Mooney viscosity (ML1+4, 125°C) of 60-80 ensures processing fluidity and is suitable for dynamic sealing of robot joints. HNBR (20-35 parts): High acrylonitrile content (34-38%) imparts oil resistance, and a degree of hydrogenation ≥95% enhances high temperature resistance (150°C for long-term use) and resistance to ozone aging, meeting the protection needs of industrial robots in oily environments; FKM (10-20 parts): Vinylidene fluoride-hexafluoropropylene copolymer (fluorine content ≥ 65%) provides excellent high temperature resistance (above 200°C) and chemical resistance. A small amount of addition can significantly improve the flame retardancy and corrosion resistance of rubber; 2. Enhance system construction: Modified nano-silica (15-25 parts): Particle size control: The primary particle size of 20-50nm provides a large specific surface area, forming a rubber-filler network structure; Surface modification: Silane coupling agent KH-570 (γ-methacryloxypropyltrimethoxysilane) achieves chemical bonding between inorganic particles and rubber matrix through "-Si-O-Si-" bond, increasing the tensile strength to ≥18MPa; Carbon nanotubes (3-8 parts): Structural design: Multi-walled carbon nanotubes (aspect ratio ≥ 1000) form a three-dimensional conductive network, and surface plasma treatment introduces oxygen-containing functional groups (such as -COOH, -OH) to improve dispersion and reduce surface resistivity to 10 8 -10 9 Ω; Synergistic effect: It forms a "rigid particle-flexible chain" reinforcement system with silica, increasing the tear strength to ≥35kN / m and extending the dynamic fatigue life by more than 30%; 3. The functional additive system is shown in Table 1:

[0024] Table 1 4. Functional additives (optional): Graphene (0.5-2 parts): A product prepared by the redox method with a monolayer ratio of ≥95% (specific surface area ≥800 m² / g). It interacts with the rubber molecular chain through π-π bonds, increasing thermal conductivity to 0.5 W / (m・K), making it suitable for robot joints with high heat dissipation requirements; Nano-cerium oxide (0.3-1 parts): Nano-particles with a particle size of 5-10nm are evenly dispersed in the rubber matrix. + / Ce 4+ The redox cycle captures free radicals, improving weathering and aging performance by 40%; Polytetrafluoroethylene powder (PTFE, 3-6 parts): Ultrafine powder with an average particle size of 1-5μm, which forms a lubricating film on the rubber surface, reducing the friction coefficient to 0.2-0.3 and the wear rate by 50%.

[0025] like Figure 1 As shown, the method for preparing the rubber material for humanoid robot protection application includes the following steps: S1. Pre-mixing: Mix EPDM rubber, hydrogenated nitrile rubber and fluororubber in an internal mixer at 80-100°C for 5-8 minutes at a speed of 40-60 r / min; S2. Filler dispersion: Add modified nano-silica, carbon nanotubes, zinc oxide, and stearic acid, heat to 110-120°C and mix for 10-15 minutes; S3. Adding functional additives: Add antioxidant RD, plasticizer DOA, flame retardant, and antistatic agent in sequence, and mix at 60-70°C for 5-8 minutes; S4. Dynamic vulcanization: Add vulcanizing agent BIPB and perform dynamic vulcanization in a twin-screw extruder at 160-180°C, with a screw speed of 200-300 r / min and a residence time of 2-4 minutes; S5. Post-treatment: After calendering, a segmented gradient vulcanization process is adopted, with the first stage at 160℃×10min, the second stage at 180℃×8min, and the third stage at 200℃×5min, and the pressure is 15-20MPa.

[0026] In this embodiment, an ultrasonic-assisted dispersion process is used in step S2, with a frequency of 20-40 kHz, a power of 500-800 W, and a processing time of 20-30 minutes.

[0027] In this embodiment, in step S4, functional additives are added before dynamic vulcanization and are uniformly injected into the rubber material through microporous injection technology.

[0028] Furthermore, the purpose of step S1 is to preliminarily mix the three main rubbers of ethylene propylene diene monomer (EPDM), hydrogenated nitrile butadiene rubber (HNBR), and fluororubber (FKM), and to destroy the forces between the molecular chains through mechanical shearing to form a uniform blend, thereby laying the foundation for the subsequent dispersion of fillers. Specifically, the following are embodied: Operation details: Equipment preparation: Use an internal mixer (with temperature and speed control functions) to clean the cavity in advance to ensure there are no residual impurities; Set the initial temperature of the internal mixer to 80-100°C (it is recommended to preheat to 80°C first, and then gradually increase the temperature to 100°C according to the molten state of the rubber) to avoid sudden temperature rise that may cause rubber oxidation or degradation; Weighing and adding raw materials: Weigh each main rubber according to the formula: EPDM: 40-60 parts by weight; Hydrogenated nitrile rubber (HNBR): 20-35 parts by weight; Fluororubber (FKM): 10-20 parts by weight; Adding order: first add EPDM (basic rubber), wait for it to soften in the internal mixer (about 1-2 minutes), then add HNBR and FKM in sequence; Principle: EPDM has a lower melting point, so the first material added can form a continuous phase, and the HNBR and FKM added later are gradually embedded in the form of a dispersed phase, reducing uneven mixing caused by viscosity differences; Mixing parameter control: Speed: set to 40-60r / min (recommended starting speed 40r / min, increase to 60r / min after the rubber material is completely wrapped around the roller); Low speed can avoid excessive shear heating, while high speed can enhance shear force to promote blending; Mixing time: 5-8 minutes, depending on the appearance of the rubber compound: Qualification standard: The rubber compound is a uniform elastomer without obvious block particles or color stratification (EPDM is white, HNBR and FKM are light yellow, and after mixing, it should be a uniform light beige color); Abnormal treatment: If there are still particles after more than 8 minutes, you can stop mixing, cut the rubber blocks manually and continue mixing, or increase the temperature to 100℃ and extend the mixing time for 2 minutes; Process monitoring and recording: Real-time monitoring of the torque value in the internal mixer: During normal mixing, the torque should first rise rapidly (rubber roller wrapping stage), then gradually decrease and stabilize (blending completion stage); Record mixing start time, temperature, speed and compound status to ensure batch consistency; Key technical points: Rubber property matching: The Mooney viscosity of EPDM (60-80) should be close to that of HNBR and FKM (HNBR Mooney viscosity is usually 70-90, FKM is 60-80) to avoid "slipping" or uneven dispersion due to excessive viscosity differences; Fluorine rubber (FKM) has a strong polarity of fluorine-containing groups, so it needs to be pre-mixed to make it initially compatible with the non-polar segments of EPDM / HNBR to reduce interface defects during subsequent filler dispersion; Temperature control logic: Low temperature (80°C) stage: mainly softens EPDM and forms a continuous phase; Medium temperature (90-100℃) stage: promote the melting of HNBR and FKM, and form a blending network through molecular chain diffusion; Safety precautions: During the mixing process, it is forbidden to open the top bolt of the internal mixer to avoid burns caused by the spraying of high-temperature rubber; If the rubber is found to be scorched (partially hardened or discolored), the mixing must be stopped immediately, the equipment must be cleaned, and the temperature / speed must be adjusted; Connection with subsequent steps: After pre-mixing is completed, the rubber material must be quickly transferred to step S2 (filler dispersion) to avoid prolonged dwelling that may cause a drop in temperature and affect the filler dispersion efficiency. If temporary storage is required, the rubber material can be cooled to room temperature (≤25°C) and sealed for storage for no more than 2 hours.

[0029] Furthermore, the purpose of step S2 is to uniformly disperse fillers such as modified nano-silica and carbon nanotubes into the pre-mixed rubber matrix, forming a reinforced network through physical entanglement and chemical coupling, thereby improving the mechanical properties and functional properties (such as conductivity and flame retardancy) of the rubber; specifically, the following is embodied: Operation details: Equipment and environment preparation: Internal mixer: Continue the equipment of step S1. No need to disassemble the rubber compound, but make sure that the chamber temperature has been stabilized to 110-120℃ (115℃ recommended) by the heating device; Ultrasonic auxiliary equipment: Connect an external ultrasonic generator, set the frequency to 20-40kHz (30kHz recommended), power to 500-800W (600W recommended), and immerse the probe into the side opening of the mixer cavity to ensure full contact with the rubber compound; Filler weighing and pretreatment: Modified nano-silica: 15-25 parts by weight, dried in an oven at 80°C for 2 hours in advance to remove surface adsorbed water (to avoid affecting the activity of the silane coupling agent); Carbon nanotubes: 3-8 parts by weight, preferably multi-walled carbon nanotubes (aspect ratio ≥ 1000), with the surface treated with plasma (e.g., oxygen plasma for 5 minutes) to further enhance dispersibility; Zinc oxide and stearic acid: 2-5 parts by weight and 1-3 parts by weight respectively. Both need to be sieved through a 200-mesh sieve to remove agglomerated particles. Filler addition order and mixing process: Delivery order: First, add the dried modified nano-silica and start the internal mixer at 40r / min for 3 minutes to allow the silica to initially embed into the rubber matrix. Add carbon nanotubes, start ultrasonic assisted dispersion simultaneously, maintain the speed at 40r / min, and process for 20-30 minutes (25 minutes is recommended); Finally, add zinc oxide and stearic acid, increase the speed to 60r / min, and mix for 5-8 minutes until the filler is completely dispersed; Ultrasound mechanism of action: The cavitation effect is generated by high-frequency vibration to destroy the agglomerates of carbon nanotubes (nano-silica has been pre-dispersed by surface modification), while promoting the formation of -Si-OC- bonds between the hydrolysis products of the silane coupling agent (KH-570) and the rubber molecular chains, thereby enhancing the interfacial bonding strength; Dispersion effect judgment: Visual inspection: After stopping the machine, take out a small amount of rubber and observe under strong light whether there are obvious filler particles (particle size > 500nm is considered unqualified); Mechanical initial screening: Take a small sample for tensile test. If the tensile strength is less than 15MPa (not up to standard), the ultrasonic treatment time needs to be extended by 5-10 minutes or the power needs to be increased to 700W. Key technical points: Filler dispersion mechanism: Modified nano-silica: One end (-Si-O-) of the silane coupling agent KH-570 condenses with the hydroxyl group on the surface of silica, and the other end (methacryloyloxy) undergoes free radical copolymerization with the double bond of rubber to form a "filler-rubber" chemical bond, preventing the filler from falling off; Carbon nanotubes: The oxygen-containing groups (such as -COOH) introduced by plasma treatment are entangled with the polar groups of rubber (such as -CN of HNBR) through hydrogen bonding, and a three-dimensional conductive network is formed under the assistance of ultrasound, and the surface resistivity can be reduced to 10 8 -10 9 Ω; Coordinated control of temperature and shear force: Temperature effect: 110-120℃ makes the rubber in a highly elastic state, the molecular chain moves actively, and it is easy to insert the filler; if the temperature is lower than 110℃, the rubber hardness is high and the filler is difficult to disperse; above 120℃ may cause slight degradation of fluororubber; Shear force control: low speed (40r / min) in the early stage to avoid carbon nanotubes from breaking due to strong shearing, and high speed (60r / min) in the later stage to ensure uniform distribution of small particle size fillers such as zinc oxide; Abnormal situation handling: Filler agglomeration: If carbon nanotubes still agglomerate after ultrasonic treatment, pause the mixing and add a small amount of plasticizer DOA (1-2 parts) to dilute the rubber viscosity before continuing to disperse; Rubber compound scorch: If the torque increases abnormally (>150N·m) during mixing, immediately reduce the temperature to 90℃ and reduce the speed to 30r / min. Check whether the filler moisture content is too high or the temperature setting is wrong; Connection with subsequent steps: After dispersion is completed, the rubber material must quickly enter step S3 (addition of functional additives). At this time, the rubber material temperature should be maintained at 100-110°C. If temporarily stored, it must be quickly cooled to below 50°C (such as by circulating cooling water) and the storage time should not exceed 1 hour to avoid filler sedimentation or premature cross-linking of the rubber.

[0030] Furthermore, the purpose of step S3 is to construct a synergistic network structure in the rubber matrix by precisely controlling the addition order and reaction conditions of the vulcanization system, antioxidant and other functional additives, thereby giving the material high strength, aging resistance and impact resistance while maintaining a soft touch, which is specifically embodied as follows: Operation details: Equipment and material preparation: Mixing mill: preheat the rollers to 60-70℃ (the front roller temperature is 5℃ higher than the rear roller temperature to create a temperature difference that promotes roller wrapping), and adjust the roller gap to 0.5-1mm; Weighing of additives: Curing agent DCP (dicumyl peroxide): 1-3 parts by weight, diluted with silicone oil to 50% active to improve dispersibility; Vulcanizing agent TAIC (triallyl isocyanurate): 0.5-2 parts by weight, powder (particle size ≤ 100 μm); Antioxidant RD (2,2,4-trimethyl-1,2-dihydroquinoline polymer): 1-3 parts by weight, melting point ≥80°C; Lubricant zinc stearate: 1-3 parts by weight, must be passed through a 300-mesh sieve to ensure there are no large particles; Addition sequence and process control: Phase 1 (vulcanization system construction): The rubber material obtained in step S2 is put into an open mill, and after the rollers are wrapped, the roller distance is adjusted to 2-3 mm, and the mill is rotated at a low speed of 10-15 r / min; Add the diluted vulcanizing agent DCP in three equal amounts, with an interval of 1 minute between each addition. Cut the left and right sides three times after each addition (to ensure that the rubber on both sides of the roller is fully mixed); Add the vulcanizing agent TAIC, increase the roller speed to 20r / min, and mix for 5 minutes, turning the rubber every 2 minutes (using the triangle bag turning method); The second stage (formation of protection system): Reduce the roller speed to 15r / min, add antioxidant RD, adjust the roller distance to 1mm, and make 5 thin passes (cut and fold the rubber material after each thin pass); Add zinc stearate, restore the roller distance to 3mm, and mix for 3 minutes until the surface is smooth and free of particles; Process monitoring and endpoint judgment: Temperature monitoring: Use an infrared thermometer to monitor the temperature of the rubber compound in real time and control it at 75-85°C (exceeding 85°C may cause premature decomposition of DCP); Dispersion test: Take a small amount of rubber compound and press it into a tablet. Observe it with a 200x microscope. The particle size of the additive must be ≤5μm and there must be no agglomeration (no more than 3 particles larger than 5μm per 100μm² field of view). Mooney viscosity test: Take a sample and test ML (1+4) at 100°C. The viscosity should be in the range of 40-60MU (if > 60MU, extend the mixing time by 2 minutes; if < 40MU, the vulcanizing agent may be decomposed and needs to be discarded); Key technical points: Synergistic mechanism of vulcanization system: DCP decomposition kinetics: At 70-85°C, the half-life of DCP is approximately 20-30 minutes. During this period, the free radicals generated by decomposition react with the allyl groups of TAIC to form CC cross-links (bond energy 347 kJ / mol), which are more stable than the CS bonds (bond energy 272 kJ / mol) of traditional sulfur vulcanization, thus improving aging resistance. The role of TAIC: As a multifunctional vulcanizing agent, its three allyl groups can simultaneously cross-link with multiple rubber molecular chains to form a three-dimensional network structure, thereby increasing the cross-linking density (the target cross-linking density is 1.2-1.5×10 -4 mol / cm³); Antioxidant compounding technology: Antioxidant RD: It captures free radicals (such as ROO·) generated by rubber oxidation, interrupts the auto-oxidation chain reaction, and its polymer structure forms a physical barrier in the rubber, slowing down the oxygen diffusion rate (oxygen permeability is reduced to ≤50cm³ / (m²·24h·0.1MPa)); Zinc stearate's dual role: As a lubricant, it reduces the friction coefficient between the rubber compound and the roller (from 0.4 to below 0.2), preventing the roller from sticking; Working in synergy with antioxidant RD, its zinc ions can chelate metal ions (such as Fe³) generated during rubber aging. + ), inhibiting catalytic oxidation; Safety and Quality Control: Storage of curing agent: DCP should be stored in a cool place below 25℃. Check the expiration date before use (shelf life is 3 months after opening). If agglomeration or discoloration is found (normally it is a white powder), the activity needs to be retested. Emergency treatment: If the temperature of the rubber compound exceeds 90°C during mixing, immediately add cooling water to cool it down to 70°C, stop adding DCP, and discard the mixed rubber compound (to avoid local over-sulfurization); Connection with subsequent steps: After mixing is completed, the rubber compound must enter step S4 (molding and vulcanization) within 1 hour, during which the rubber compound temperature must be maintained at 40-50°C (it can be stored in an insulated box); if it needs to be stored for more than 1 hour, the rubber compound sheet should be cooled to room temperature and re-mixed at 60°C on an open mill for 3 minutes before use to ensure uniform distribution of the additives.

[0031] Furthermore, the purpose of step S4 is to form a stable cross-linked structure between the rubber molecular chains through a high temperature and high pressure environment, while precisely controlling the mold temperature field and pressure distribution to ensure that the material obtains the target shape and mechanical properties (Shore hardness 70-80A, tensile strength ≥18MPa), which is specifically reflected in: Operation details: Equipment and mold preparation: Flatbed vulcanizing press: preheat to 160-170°C (165°C recommended), set the pressure to 10-15 MPa (adjust according to the thickness of the product, increase 1 MPa for every 1 mm increase in thickness); Mold design: The mold cavity size is 0.2-0.3mm smaller than the nominal size of the product on one side (to compensate for the vulcanization shrinkage rate, the shrinkage rate of EPDM / HNBR / FKM blend is about 1.8-2.2%); The runner is designed to be fan-shaped, with a main runner diameter of 8-10mm, a branch runner diameter of 5-6mm, and a gate thickness of 0.8-1.2mm; The depth of the exhaust groove is 0.02-0.05mm (to prevent the rubber from overflowing), the width is 5-10mm, and the spacing is 20-30mm; Rubber pretreatment and mold loading: Preforming: The rubber obtained in step S3 is weighed according to the weight of the product (5-8% excess to ensure that the mold cavity is full), and pressed into a disc or square with uniform thickness, and the size is 10-15% larger than the mold feed opening; Mold coating release agent: Use fluorosilicone release agent (such as Shin-Etsu KF-96), spray evenly with a spray gun, control the film thickness to 0.5-1μm, and bake at 100℃ for 5 minutes after coating; Vulcanization process parameter control: Warming up stage: After closing the mold, maintain a low pressure of 5MPa for 1 minute to allow the rubber to flow and fill the mold cavity under low resistance; Rapidly increase the pressure to 15 MPa and simultaneously increase the temperature to 165°C at a rate of 10°C / min (the total time from mold closing to reaching the target temperature is ≤ 3 minutes); Heat preservation and pressure holding stage: maintain 165℃, 15MPa for 10-15 minutes (the specific time is calculated according to the thickness of the product, 1 minute for each millimeter of thickness); Cooling and demoulding stage: In the pressure-maintaining state, circulating cooling water is introduced to reduce the mold temperature to below 60°C within 5 minutes; Release the pressure and open the mold, and use compressed air (0.5MPa) to assist demoulding to avoid deformation of the product caused by forced pulling; Process monitoring and quality control: Temperature monitoring: embed thermocouples at key locations of the mold (such as gate, cavity center, and edge) to ensure that the temperature difference is ≤±3°C; Pressure curve recording: During the vulcanization process, the pressure fluctuation shall not exceed ±10% of the set value. If the pressure drops suddenly (>15%), there may be mold leakage and the machine must be stopped immediately for inspection. Vulcanization degree detection: Use a vulcanizer for online monitoring, and the deviation of t90 (positive vulcanization time) shall not exceed ±0.5 minutes; Take the cross section of the product for observation. There should be no bubbles or stratification, and the cross section should be uniform in color (light brown). Key technical points: Cross-linking reaction kinetics: At 165°C, DCP decomposes to generate free radicals that initiate crosslinking between the allyl groups of TAIC and the double bonds of rubber. The reaction rate constant k is 0.023 min -1 , calculated by the Arrhenius equation, the cross-linking efficiency at this temperature is 2.5 times higher than that at 150°C, but the time must be strictly controlled to prevent oversulfurization (the cross-linking bond breaking rate exceeds the formation rate); Temperature field uniformity control: The mold adopts a circulating oil heating system, and a spiral oil circuit is designed around the mold cavity to ensure that the temperature difference between the oil inlet and outlet is ≤5℃; For complex products (such as multi-rib structures), additional heating rods are designed in the rib area to compensate for uneven heat dissipation caused by differences in rubber thickness; Defect prevention measures: Bubble problem: Before vulcanization, the rubber compound is subjected to vacuum degassing treatment (maintained at -0.09 MPa for 10 minutes); Install an exhaust valve at the highest point of the mold, and exhaust for 30 seconds before increasing the pressure after closing the mold; The flash is too thick: control the surface roughness of the mold parting surface Ra ≤ 0.8μm, and polish it with metallographic sandpaper before each use; Connection with subsequent steps: After vulcanization is completed, the product must proceed to step S5 (post-processing) within 24 hours, avoiding direct sunlight and contact with oil. If storage is required, it should be placed in an environment of 23±2℃ and 50±5% humidity, and the stacking height should be ≤50cm (to prevent deformation due to its own weight).

[0032] Furthermore, the purpose of step S5 is to eliminate internal stress and stabilize the cross-linked structure through gradient heat treatment, and improve the weather resistance and anti-adhesion properties of the material in combination with surface modification, and ultimately obtain a bionic protective material with excellent comprehensive performance, which is specifically embodied as follows: Operation details: Gradient heat treatment process: The first stage: Place the vulcanized product in a blast drying oven, raise the temperature to 100°C at a rate of 2°C / min, and keep it at that temperature for 2 hours (to remove residual moisture and low molecular weight volatiles); The second stage: continue to heat up to 150℃ at a rate of 1℃ / min and keep warm for 4 hours (to fully decompose the unreacted vulcanizing agent and improve the cross-linking network); The third stage: naturally cool to 60℃ and then take out (cooling rate ≤ 5℃ / min to prevent rapid cooling from generating new stress); Surface plasma treatment: Equipment parameters: radio frequency plasma equipment, power 100-150W, processing gas is argon + oxygen (volume ratio 3:1), gas pressure 50-100Pa; Processing flow: Place the product in a vacuum chamber and evacuate to below 10Pa; Introduce mixed gas at a flow rate of 50-80 sccm, start plasma discharge, and process for 3-5 minutes; After treatment, cool to room temperature under nitrogen protection (to prevent oxidation of surface active groups); Nano coating application: Coating formula: Nano-silica sol (particle size 10-20nm): 20-30wt%; Fluorosilane coupling agent (such as KH-570F): 5-10wt%; Anhydrous ethanol: 60-75wt%; Coating process: Immerse the product in the coating solution and pull it up at a constant speed of 5 cm / min; Dry in an oven at 80°C for 1 hour to evaporate the ethanol; Heat to 120℃ and cure for 2 hours to form a transparent protective film with a thickness of 50-100nm; Performance testing and trimming: Hardness test: Use Shore A hardness tester to test 5 points evenly on the surface of the product. The hardness value deviation is ≤±2A. Surface energy detection: The water contact angle is tested by a contact angle meter and should be ≥110° (about 85° before treatment); Flash trimming: Use a sharp blade to manually remove the flash, and control the angle between the incision and the surface of the product at 45-60 degrees to avoid damaging the body; Key technical points: Internal stress relief mechanism: In the temperature range of 100-150°C, the rubber molecular segments gain enough energy to rearrange, gradually releasing the elastic stress frozen during the vulcanization process. DSC testing verified that the peak width of the thermal enthalpy change of the treated product narrowed from 15°C to 8°C, indicating a more uniform molecular chain arrangement. Surface modification synergistic effect: Plasma treatment: introducing polar groups such as hydroxyl (-OH) and carboxyl (-COOH) on the surface of the material, increasing the surface energy from 35mJ / m² to 50mJ / m² and enhancing the adhesion of the coating; Nanocoating: Silica particles form a microscopic rough structure, and fluorosilane provides low surface energy (-CF3 groups). The two work together to achieve a superhydrophobic effect (sliding angle <10°) while improving surface wear resistance (wear volume is reduced by 40%). Key points of quality control: Heat treatment time-temperature curve: If the heating rate is greater than 2°C / min, it may cause the surface to overheat and form an oxide layer; insufficient holding time will result in low crosslinking density (target crosslinking density 1.5-1.8×10 -4 mol / cm³); Coating thickness control: achieved by adjusting the pulling rate and solution concentration. Thickness <50nm will result in insufficient protection, while thickness >100nm will easily cause cracks. Connection with subsequent steps: After post-processing is completed, the products need to undergo final inspection (including full inspection of dimensional accuracy, surface defects, physical properties, etc.), and are packaged after passing the inspection. The packaging material is PE plastic bag + EPE pearl cotton cushioning layer, each group of 10 pieces is stored in a warehouse at 20±5℃ and humidity ≤60%, with a shelf life of 12 months.

[0033] In this embodiment, the rubber material is used to prepare the humanoid robot protective component, which includes a multi-layer composite structure, which is composed of the following from the inside to the outside: The base fabric reinforcement layer is aramid fiber braid with a thickness of 0.2-0.5mm; Buffer layer, rubber material, thickness 1-2mm; Functional surface layer, rubber material containing functional additives, thickness 0.5-1mm; Chemical bonding is achieved between the base fabric reinforcement layer, buffer layer and functional surface layer through plasma treatment, and the interface peel strength is ≥15N / mm.

[0034] Furthermore, the surface of the functional surface layer is treated with laser microtexturing to form honeycomb grooves with a depth of 50-100 μm, a friction coefficient of ≤0.3, and a contact angle of ≥150°.

[0035] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A rubber material for humanoid robot protection applications, characterized by: The following components are included by weight: 40-60 parts of EPDM, 20-35 parts of hydrogenated nitrile rubber HNBR, 10-20 parts of fluororubber FKM, 15-25 parts of modified nano-silica, 3-8 parts of carbon nanotubes, 2-5 parts of zinc oxide, 1-3 parts of stearic acid, 1-4 parts of antioxidant RD, 0.5-2 parts of di-tert-butyl peroxide BIPB, 5-10 parts of plasticizer dioctyl adipate DOA, 8-15 parts of flame retardant decabromodiphenyl ethane, 2-5 parts of antistatic agent quaternary ammonium salt compound; The modified nano-silica is nano-scale silica surface-modified with silane coupling agent KH-570, with a particle size of 20-50 nm; The carbon nanotubes are multi-walled carbon nanotubes with an aspect ratio of ≥1000, and the surface is treated with plasma to enhance dispersibility.

2. The rubber material for humanoid robot protection according to claim 1, characterized in that: The Mooney viscosity of the EPDM rubber is 60-80, and the ethylene content is 50-60wt%; the acrylonitrile content of the hydrogenated nitrile rubber is 34-38%, and the degree of hydrogenation is ≥95%; the fluororubber is a vinylidene fluoride-hexafluoropropylene copolymer, and the fluorine content is ≥65%.

3. The rubber material for humanoid robot protection according to claim 1, characterized in that: The flame retardant further comprises a composite system of zinc borate and magnesium hydroxide in a mass ratio of 1:2, with a total addition amount of 5-10 parts; the antistatic agent is octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate, with a surface resistivity of ≤1×10 9 Ω.

4. The rubber material for humanoid robot protection according to claim 1, characterized in that: Also included are functional additives, including by weight: 0.5-2 parts of graphene, 0.3-1 parts of nano-cerium oxide, and 3-6 parts of polytetrafluoroethylene micropowder PTFE; The graphene is a product prepared by a redox method with a single-layer rate of ≥95% and a specific surface area of ≥800m² / g.

5. A method for preparing a rubber material for use in protective applications of a humanoid robot according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Pre-mixing: Mix EPDM rubber, hydrogenated nitrile rubber and fluororubber in an internal mixer at 80-100°C for 5-8 minutes at a speed of 40-60 r / min; S2. Filler dispersion: Add modified nano-silica, carbon nanotubes, zinc oxide, and stearic acid, heat to 110-120°C and mix for 10-15 minutes; S3. Adding functional additives: Add antioxidant RD, plasticizer DOA, flame retardant, and antistatic agent in sequence, and mix at 60-70°C for 5-8 minutes; S4. Dynamic vulcanization: Add vulcanizing agent BIPB and perform dynamic vulcanization in a twin-screw extruder at 160-180°C, with a screw speed of 200-300 r / min and a residence time of 2-4 minutes; S5. Post-treatment: After calendering, a segmented gradient vulcanization process is adopted, with the first stage at 160℃×10min, the second stage at 180℃×8min, and the third stage at 200℃×5min, and the pressure is 15-20MPa.

6. The method for preparing a rubber material for humanoid robot protection according to claim 5, characterized in that: In step S2, an ultrasonic wave-assisted dispersion process is used with a frequency of 20-40 kHz, a power of 500-800 W, and a processing time of 20-30 minutes.

7. The method for preparing a rubber material for humanoid robot protection according to claim 5, characterized in that: In step S4, functional additives are added before dynamic vulcanization and uniformly injected into the rubber material through microporous injection technology.

8. The rubber material for humanoid robot protection according to claim 1, characterized in that: The rubber material is used to prepare a humanoid robot protective component, which includes a multi-layer composite structure, which is composed of the following from the inside to the outside: The base fabric reinforcement layer is aramid fiber braid with a thickness of 0.2-0.5mm; Buffer layer, rubber material, thickness 1-2mm; Functional surface layer, rubber material containing functional additives, thickness 0.5-1mm; Chemical bonding is achieved between the base fabric reinforcement layer, buffer layer and functional surface layer through plasma treatment, and the interface peel strength is ≥15N / mm.

9. The rubber material for humanoid robot protection according to claim 8, characterized in that: The surface of the functional surface layer is processed by laser micro-texturing to form honeycomb grooves with a depth of 50-100 μm, a friction coefficient of ≤0.3, and a contact angle of ≥150°.

Images