Composite material tendon rope for robot and ultra-high molecular rope core of composite material tendon rope

Abstract

The invention relates to the technical field of robots, in particular to a composite tendon rope for a robot and an ultra-high molecular rope core of the composite tendon rope. The rope core takes maleic anhydride grafted ultra-high molecular weight polyethylene, amino-terminated nylon 6 and a dynamic cross-linking agent as core raw materials, a stable chemical network is constructed through amido bond grafting and diselenide bond cross-linking of an anhydride group and an amino group, and the structural stability and the mechanical property are improved in cooperation with a three-stage hot stretching and alternate weaving process. The tendon rope is of a'ultra-high molecular rope core-outer metal wire 'core-shell structure, the metal wires are woven in a radial mode to evenly wrap the rope core, then shaping is conducted at the temperature of 80-120 DEG C to eliminate weaving stress, and a composite system with axial bearing and radial protection cooperating is formed. The problems that a traditional tendon rope is insufficient in strength, prone to creep deformation, poor in fatigue resistance and the like are solved, the low deformation, high abrasion resistance and low-temperature adaptability are achieved, and the requirements for heavy load, high-frequency motion and complex working conditions of a robot driving system can be stably met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of robots, and particularly relates to a composite tendon for robots and an ultrahigh molecular rope core thereof. BACKGROUND

[0002] As a core component of the driving and transmission system of robots, the robot tendon is widely used in humanoid robot dexterous hands, industrial robot arms and other scenes, and its performance directly determines the motion accuracy, carrying capacity and service life of the robot. The robot tendons on the market at present mainly rely on pure ultrahigh molecular weight polyethylene (UHMWPE) ropes, metal wire ropes or ordinary polymer-metal composite ropes, but all have obvious performance short boards: although the pure UHMWPE rope has the characteristics of lightweight and low friction, its molecular chain is easy to slip, the creep rate is high when bearing load for a long time, and the fatigue resistance is poor, and after high-frequency reciprocating stretching, the deformation is easy to exceed the tolerance, resulting in a decrease in the positioning accuracy of the robot. The metal wire rope has high strength and anti-creep, but has large density and transmission inertia, which does not meet the lightweight design requirements of the robot, and is easy to be corroded and broken after long-term use. In order to balance the strength and lightweight, the existing technology attempts to prepare the rope core by physically blending UHMWPE and nylon, but the polarity difference between the two is significant, there is no effective covalent connection, the blending system is easy to separate, the tensile strength and interfacial bonding force are greatly reduced, and it cannot meet the demand of heavy load scene; some schemes add static crosslinking agents such as peroxide to improve the anti-creep performance, but it leads to the decrease of the toughness and fatigue resistance of the rope core, and micro-cracks are easy to occur due to stress concentration during high-frequency motion. In addition, the existing dynamic crosslinking agent (such as a crosslinking agent containing a disulfide bond) has poor thermal stability and is easy to decompose at a melt processing temperature of 220-250 DEG C in a double screw extruder, so it is difficult to form a stable dynamic crosslinking network, and it cannot balance the anti-creep and fatigue resistance. In the aspect of external reinforcement, the existing technology mainly adopts simple coating of the rope core with metal wires, and only relies on the braiding process to realize preliminary fixation, the combination between the metal wires and the rope core is loose, and relative slip is easy to occur during the robot motion; some schemes add adhesives to improve the bonding force, but the adhesives are brittle after solidification, which will greatly reduce the overall toughness of the tendon, and cannot adapt to low temperature (below-20 DEG C) working conditions-the impact toughness of the existing rope core decreases sharply in low temperature environment, and is easy to break in complex scenes such as outdoor and cold chain, which cannot meet the multi-working condition adaptation requirements of the robot. SUMMARY

[0003] The present application aims at solving the problems in the prior art, and provides a composite tendon for robots and an ultrahigh molecular rope core thereof.

[0004] Based on the above purpose, the present application provides a kind of super high molecular rope core, including the following weight parts raw materials: maleic anhydride grafted super high molecular weight polyethylene: 60-70 parts, amino-nylon 6: 20-30 parts, dynamic crosslinking agent: 2-4 parts, silicon copper powder: 1-2 parts, antioxidant: 0.5-1.5 parts; The preparation method of the maleic anhydride grafted super high molecular weight polyethylene is as follows: The super high molecular weight polyethylene powder is ultrasonically cleaned with ethanol for 10-20 min, dried, then added into xylene and dibenzoyl peroxide, replaced with nitrogen three times, heated to 70-90 DEG C, added maleic anhydride under stirring, reacted for 4-6 h, removed xylene by suction filtration, the obtained solid was washed with ethanol, then extracted with acetone by soxhlet extraction for 24 h, dried to obtain maleic anhydride grafted super high molecular weight polyethylene; the chemical reaction schematic diagram is as follows: The preparation method of the dynamic crosslinking agent is as follows: (1) under nitrogen protection, selenium powder is added into deionized water, cooled to 0 DEG C, drop 1 mol / L sodium borohydride aqueous solution, drop control reaction temperature not more than 0 DEG C when drop, after drop, add tetrabutylammonium hydrogen sulfate, restore room temperature, stirring reaction 1-2 h, then add 4-chlorobutyryl chloride toluene solution, continue to react for 6-12 h, after reaction, wash with 5% sodium bicarbonate aqueous solution, separate organic phase and aqueous phase, dry organic phase with anhydrous sodium sulfate, filter, remove solvent by rotary evaporation, then distill under reduced pressure, collect 50 DEG C fraction to obtain gamma-selenobutyrolactone; the chemical reaction equation is as follows: In the reaction, selenium powder (Se) is first reacted with sodium borohydride (NaBH4) in aqueous solution: NaBH4 as reducing agent, Se is reduced to active selenium species, reaction control temperature is below 0 DEG C, to avoid side reactions, then add tetrabutylammonium hydrogen sulfate (phase transfer catalyst), which can transfer selenium active species in aqueous phase to organic phase, promote reaction with 4-chlorobutyryl chloride, acyl chloride group in 4-chlorobutyryl chloride has strong electrophilicity (carbonyl carbon is electrophilic site), attacked by selenium active species (nucleophile) in organic phase, nucleophilic substitution reaction (chlorine atom is replaced by selenium) occurs; at the same time, intramolecular cyclization reaction occurs, forming five-membered lactone ring structure of gamma-selenobutyrolactone; the product is characterized by H NMR; (2) under nitrogen protection, gamma-selenobutyrolactone and 6-amino-2-(aminomethyl)naphthalene are added into tetrahydrofuran, heated to 40-50 DEG C, reacted for 1-3 h, cooled to room temperature, then add deionized water, extract with ethyl acetate three times, dry the combined organic phase with anhydrous sodium sulfate, filter, remove solvent by rotary evaporation, the obtained crude product is purified by silica gel column chromatography, gradient elution to obtain dynamic crosslinking agent; the chemical reaction equation is as follows: The five-membered lactone ring of γ-selenobutyrolactone is reactive, and under the action of the primary amino group of 6-amino-2-(aminomethyl)naphthalene, a nucleophilic ring-opening reaction occurs: the amino group (a strong nucleophile) attacks the carbonyl carbon (an electrophilic site) of the lactone ring, the carbon-oxygen bond of the lactone ring is broken, and after ring opening, an amido group and a selenium-containing chain structure are formed. Due to the structural characteristics of the reactants, the ring-opening products of two molecules are further connected through the selenium atom, and finally a dynamic crosslinker containing a diselenide bond (-Se-Se-) and a terminal amino group is formed. The product is characterized by H NMR.

[0005] Preferably, the antioxidant is one of antioxidant 1010 or antioxidant 168.

[0006] Preferably, in the preparation method of the maleic anhydride grafted ultra-high molecular weight polyethylene, the average molecular weight of the ultra-high molecular weight polyethylene is greater than or equal to 10 6 .

[0007] Preferably, in the preparation method of the maleic anhydride grafted ultra-high molecular weight polyethylene, the weight ratio of the ultra-high molecular weight polyethylene powder, xylene, dibenzoyl peroxide and maleic anhydride is 1:4-6:0.01-0.02:0.3-0.5.

[0008] Preferably, in the (1), the molar ratio of selenium powder and 4-chlorobutyryl chloride is 1:1-1.2.

[0009] Preferably, in the (1), the weight ratio of selenium powder, deionized water, 1 mol / L sodium borohydride aqueous solution and tetrabutylammonium hydrogen sulfate is 1:8-12:0.9-1.1:0.1-0.3.

[0010] Preferably, in the (1), the concentration of the 4-chlorobutyryl chloride toluene solution is 1 mol / L.

[0011] Preferably, in the (2), the molar ratio of γ-selenobutyrolactone and 6-amino-2-(aminomethyl)naphthalene is 1:1.1-1.3.

[0012] Preferably, in the (2), the weight ratio of γ-selenobutyrolactone, tetrahydrofuran and deionized water is 1:8-12:15-25.

[0013] Preferably, in the (2), the gradient elution refers to the volume ratio of petroleum ether and ethyl acetate in each step eluent is 1:0, 10:1, 5:1 to 2:1 in turn.

[0014] Further, the present application also provides a preparation method of the above-mentioned ultra-high molecular rope core, comprising the following steps: S1. Maleic anhydride grafted ultra-high molecular weight polyethylene, amino-terminated nylon 6, silicon copper powder and antioxidant are added into a high-speed mixer, and high-speed mixing is carried out at room temperature for 10-20 min to obtain a premix, and the premix is added into a twin-screw extruder, and the temperature of the first zone is set to 130-150 DEG C, the temperature of the second zone is set to 170-190 DEG C, the temperature of the third zone is set to 220-240 DEG C, the temperature of the fourth zone is set to 230-250 DEG C, the temperature of the fifth zone is set to 220-230 DEG C, and the screw rotation speed is 70-90 rpm, and a dynamic crosslinking agent is added into the fifth zone of the extruder, and the extrudate is cooled by water and granulated to obtain a blending masterbatch; in the process, the maleic anhydride grafted ultra-high molecular weight polyethylene reacts with the amino-terminated nylon 6 and the dynamic crosslinking agent, the maleic anhydride groups in the maleic anhydride grafted ultra-high molecular weight polyethylene react with the amino groups in the amino-terminated nylon 6, so that the amino-terminated nylon 6 is grafted on the molecular chain of the ultra-high molecular weight polyethylene by chemical bonding, and a chemical reaction schematic diagram is as follows: ; meanwhile, the maleic anhydride groups in the maleic anhydride grafted ultra-high molecular weight polyethylene also react with the amino groups in the dynamic crosslinking agent molecules, so that different ultra-high molecular weight polyethylenes are crosslinked by diselenium bonds, and a chemical reaction schematic diagram is as follows: ; S2. The blending masterbatch is added into decalin, heated to 130-140 DEG C, stirred for 1.5-2.5 h, and subjected to defoaming treatment for 30 min to obtain a gel solution, and the gel solution is pumped into a spinneret by a spinning pump, pre-stretched by 2-4 times in air to form a nascent fiber, and then immersed in a 55-65 DEG C decalin coagulation bath for 5-10 min to cause the solvent to be precipitated, so that a solidified fiber is obtained, and then subjected to three-stage hot stretching, and the stretching temperature is set to 75-85 DEG C for the first stage, 115-125 DEG C for the second stage and 135-145 DEG C for the third stage, and the stretching multiples of the three stages are 2-3, 2-3 and 1.5-2 respectively, so that a core single yarn is obtained. S3. The core single yarn is knitted by using a knitting machine, and the Z twist direction and the S twist direction are alternately twisted, and the knitting density is 80-120 ends / inch, so that a core blank is obtained, and finally, the core blank is placed in a vacuum drying box for setting to eliminate the knitting internal stress, so that an ultra-high molecular core is obtained.

[0015] Preferably, the blending masterbatch and the decalin in S2 are in a weight ratio of 1:4-6.

[0016] Preferably, the spinneret hole diameter in S2 is 0.08-0.12 mm, and the hole number is 40-60.

[0017] Further, the application also provides a composite tendon for a robot, which is made of the above-mentioned ultra-high molecular core and comprises the following steps: The outer layer reinforcing fiber is uniformly coated outside the super high molecular rope core in a plurality of twisted strands, a plurality of fiber strands are radially woven around the central rope core to form a composite structure of the central rope core and the outer layer reinforcing layer; the woven tendon is placed in an environment of 80-120°C for 1-2h to be shaped and to eliminate weaving stress, and a composite material tendon for robots is obtained.

[0018] Preferably, the outer layer reinforcing fiber refers to a metal wire, including one of a steel wire or a tungsten wire.

[0019] Preferably, the action mechanism of the composite material tendon for robots is as follows: The chemical network of the rope core is the basis of the performance of the tendon, the anhydride groups in the maleic anhydride grafted ultra high molecular weight polyethylene undergo nucleophilic addition-elimination reaction with the primary amino groups of the amino-terminated nylon 6 in the melting environment of the twin-screw extruder to generate stable amide bonds, this covalent connection solves the compatibility problem of the non-polar UHMWPE and the polar nylon 6, avoids the phase separation and stress concentration of traditional physical blending, and makes the two polymers form a uniform and continuous matrix, the ultra high molecular weight polyethylene provides a flexible long chain skeleton, the nylon 6 provides a rigid crystalline segment, and the two cooperatively build the basic mechanical framework of the rope core; at the same time, the end amino groups of the dynamic crosslinking agent (containing diselenium bond) react with the anhydride groups of the maleic anhydride grafted ultra high molecular weight polyethylene to crosslink different ultra high molecular weight polyethylene molecular chains through diselenium bond (-Se-Se-) to form a reversible dynamic network; in addition, the silicone powder in the raw material plays a lubricating role when melting and blending, reduces the high melt viscosity of the ultra high molecular weight polyethylene, guarantees the uniformity of fiber forming in the spinning process, the antioxidant inhibits the oxidative degradation of PE and nylon 6 at high temperature, and ensures the stability of the molecular chain structure, thereby providing protection for the mechanical properties of the rope core; The ultra high molecular weight polyethylene itself has a ultra high molecular weight ≥10 6 After three-stage thermal stretching after spinning, a highly ordered fiber bundle is formed, which can efficiently bear the axial load of the robot tendon; the nylon 6 crystalline region connected by amide bonds can limit the slippage of the ultra high molecular weight polyethylene molecular chains through intermolecular forces, and further restricts the movement of the molecular chains in cooperation with the diselenium bond crosslinking network, thereby fundamentally improving the defect of pure ultra high molecular weight polyethylene that is prone to creep, reducing the deformation rate of the tendon after long-term stress, and guaranteeing the positioning accuracy of the robot; at the same time, the dynamic characteristics of the diselenium bond endow the tendon with excellent fatigue resistance and impact resistance: when the tendon bears high-frequency reciprocating stretching (such as the opening and closing of the fingers of a humanoid robot), the diselenium bond will reversibly break due to stress, absorb and dissipate impact energy, and reorganize in the stress relaxation stage to avoid the expansion of micro-cracks, so that the tendon still has a relatively high strength retention rate after multiple fatigue cycles; the flexible segment of the nylon 6 and the toughness of the ultra high molecular weight polyethylene also cooperatively enable the rope core to maintain relatively high impact toughness at low temperatures, adapt to complex working conditions such as outdoor and cold chain conditions; The composite structure of the outer metal wire and the rope core further enhances the engineering adaptability of the tendon chord and compensates for the performance shortcomings of the pure polymer rope core. The metal wire has high rigidity, high wear resistance, and excellent resistance to radial deformation. After being evenly wrapped around the rope core in a radial weave, it forms a dual function of physical protection and mechanical reinforcement: On the one hand, the metal wire can directly resist the frictional wear between the tendon chord and the robot joint components—during robot movement, the tendon chord needs to frequently come into contact with joint pulleys and grooves. The high hardness of the metal wire can prevent the direct exposure and wear of the rope core polymer, greatly extending the service life of the tendon chord; on the other hand, the high rigidity of the metal wire can... This reduces the radial load borne by the chords, minimizing stress concentration in the core during bending and torsion. Especially in heavy-duty robot scenarios, the metal wires can form an axial-radial all-around force-bearing system with the core. The core bears the main axial tensile load, while the metal wires resist radial compression and bending deformation, preventing the core from breaking due to excessive local stress. In addition, the metallic properties of the metal wires can improve the dimensional stability of the chords. Even at high temperatures, it can limit the thermal expansion of the core, ensuring that the transmission accuracy of the chords is not affected by temperature fluctuations. This perfectly meets the core requirements of robot drive systems: "high strength, wear resistance, and deformation resistance."

[0020] The beneficial effects of this invention are: 1. This invention addresses the performance limitations of traditional polymer-blended rope cores at the molecular level by constructing a chemical synergistic system of "maleic anhydride-grafted ultra-high molecular weight polyethylene (PE-g-MAH) - amino-terminated nylon 6 - diselenylene bond dynamic crosslinking agent". The anhydride groups of PE-g-MAH react fully with the primary amino groups of amino-terminated nylon 6 to form amide bonds, completely eliminating the compatibility issues between nonpolar UHMWPE and polar nylon 6 and avoiding stress concentration caused by phase separation. Simultaneously, the diselenylene bonds of the dynamic crosslinking agent further crosslink the UHMWPE molecular chains, forming a "amide bond-diselenylene bond" dual covalent network. This network not only restricts UHMWPE molecular chain slippage to reduce creep rate but also enhances overall tensile strength through synergistic force distribution among the molecular chains. This chemical network gives the rope core both high strength and low deformation characteristics, enabling it to stably withstand the axial loads of robot drive systems while ensuring positioning accuracy after long-term use, meeting the requirements of heavy-load and high-precision scenarios such as robotic arm grasping and finger opening / closing.

[0021] 2. The diselenylene bond dynamic crosslinking agent prepared in this invention achieves a balance between thermal stability and dynamic properties through molecular structure design, solving the problem of easy decomposition of existing dynamic crosslinking agents (such as disulfide bond-based agents) during high-temperature processing. The crosslinking agent uses 6-amino-2-(aminomethyl)naphthalene as raw material. Its naphthalene ring conjugated structure can stabilize the diselenylene bond through electron delocalization, ensuring structural stability of the diselenylene bond at a melt processing temperature of 220-250℃ in a twin-screw extruder, guaranteeing sufficient reaction with PE-g-MAH and terminal amino nylon 6 to form a complete crosslinking network. Simultaneously, the diselenylene bond possesses reversible breakage-recombination characteristics. When the robot tendon tract is subjected to high-frequency reciprocating tension, it can absorb fatigue stress through bond breakage and restore network integrity through bond recombination. This avoids creep caused by molecular chain slippage and prevents early failure caused by microcrack propagation, significantly extending the service life of the tendon tract in high-frequency motion scenarios (such as the high-frequency opening and closing of humanoid robot fingers).

[0022] 3. This invention employs a core-shell composite structure of "ultra-polymer rope core - outer metal wire," combined with specific weaving and shaping processes, significantly improving the engineering adaptability of the tendon chord. The rope core is woven by alternating Z-twist and S-twist twisting, combined with vacuum shaping to eliminate internal stress, forming a uniformly structured load-bearing skeleton. The outer metal wire uniformly covers the rope core in a radial weaving pattern and is tightly bonded to the rope core after shaping at 80-120℃. This structure allows the outer metal wire to directly resist frictional wear from robot joint pulleys and grooves, avoiding wear caused by direct exposure of the rope core polymer. At the same time, the high rigidity of the metal wire can distribute radial loads, reducing stress concentration during rope core bending and torsion. In addition, the metallic properties of the metal wire can limit the thermal expansion of the rope core in high-temperature environments (such as robot motor heat dissipation), ensuring that the tendon chord transmission accuracy is not affected by temperature fluctuations, adapting to the complex transmission conditions of robots.

[0023] 4. This invention, through synergistic raw material selection and process design, endows tendon ropes with excellent low-temperature adaptability and anti-aging capabilities, breaking the limitations of traditional tendon ropes on their operating environment. The flexible segments of nylon 6 in the rope core synergize with the toughness of UHMWPE, and combined with the dynamic energy dissipation effect of diselenyl bonds at low temperatures, it can still maintain good impact toughness even in a -20℃ environment, avoiding brittle fracture at low temperatures; the antioxidants added to the raw materials can inhibit the oxidative degradation of PE and nylon 6 under the high temperature of twin-screw extrusion, ensuring the long-term stability of the molecular chain structure; the silicone powder can reduce the high melt viscosity of UHMWPE, ensuring the uniformity of fiber formation during spinning and avoiding performance fluctuations caused by forming defects. These designs allow the tendon ropes to be stably applied in complex scenarios such as outdoor low temperatures and cold chain logistics, significantly expanding the operating range of robots. Attached Figure Description

[0024] Figure 1 The 1H NMR spectrum of γ-selenobutyrolactone prepared in Example 6 of this invention; Figure 2 The H NMR spectrum of the dynamic crosslinking agent prepared in Example 6 of this invention; Figure 3 This is a schematic diagram of the cross-sectional structure of the composite material tendon ligament for robots prepared according to the present invention.

[0025] Among them: 1. Ultra-high molecular weight rope core, 2. Metal wire. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0027] Preparation Example 1: A specific method for preparing maleic anhydride-grafted ultra-high molecular weight polyethylene includes the following steps: 1 kg of ultra-high molecular weight polyethylene powder was ultrasonically cleaned with ethanol for 10 min, dried, and then added to 4 kg of xylene along with 10 g of benzoyl peroxide. The mixture was purged with nitrogen three times, heated to 70 °C, and 300 g of maleic anhydride was added with stirring. The reaction was carried out for 4 h, and xylene was removed by filtration. The resulting solid was washed with ethanol, then extracted with acetone using a Soxhlet extractor for 24 h and dried to obtain maleic anhydride-grafted ultra-high molecular weight polyethylene.

[0028] Preparation Example 2: A specific method for preparing maleic anhydride-grafted ultra-high molecular weight polyethylene, including the following steps: 1 kg of ultra-high molecular weight polyethylene powder was ultrasonically cleaned with ethanol for 15 min, dried, and then added to 5 kg of xylene along with 15 g of benzoyl peroxide. The mixture was purged with nitrogen three times, heated to 80 °C, and 400 g of maleic anhydride was added with stirring. The reaction was carried out for 5 h, and xylene was removed by filtration. The resulting solid was washed with ethanol, then extracted with acetone using a Soxhlet extractor for 24 h and dried to obtain maleic anhydride-grafted ultra-high molecular weight polyethylene.

[0029] Preparation Example 3: A specific method for preparing maleic anhydride-grafted ultra-high molecular weight polyethylene, including the following steps: 1 kg of ultra-high molecular weight polyethylene powder was ultrasonically cleaned with ethanol for 20 min, dried, and then added to 6 kg of xylene along with 20 g of benzoyl peroxide. The mixture was purged with nitrogen three times, heated to 90 °C, and 500 g of maleic anhydride was added with stirring. The reaction was carried out for 6 h, and the xylene was removed by filtration. The resulting solid was washed with ethanol, then extracted with acetone using a Soxhlet extractor for 24 h and dried to obtain maleic anhydride-grafted ultra-high molecular weight polyethylene.

[0030] Preparation Example 4: The specific preparation method of the dynamic crosslinking agent includes the following steps: (1) Under nitrogen protection, 20g of selenium powder was added to 160g of deionized water, the temperature was lowered to 0℃, and 18g of sodium borohydride aqueous solution with a concentration of 1mol / L was added dropwise. The reaction temperature was controlled not to exceed 0℃ during the dropwise addition. After the dropwise addition was completed, 2g of tetrabutylammonium bisulfate was added, the temperature was restored to room temperature, and the reaction was stirred for 1h. Then, 253.29g of toluene solution of 4-chlorobutyryl chloride with a concentration of 1mol / L was added, and the reaction was continued for 6h. After the reaction was completed, the organic phase and the aqueous phase were separated by washing with 5% sodium bicarbonate aqueous solution. The organic phase was dried with anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation. Then, the fraction at 50℃ was collected by vacuum distillation to obtain γ-selenobutyrolactone. (2) Under nitrogen protection, 20g of γ-selenobutyrolactone and 25.42g of 6-amino-2-(aminomethyl)naphthalene were added to 160g of tetrahydrofuran, heated to 40℃, reacted for 1h, cooled to room temperature, and 300g of deionized water were added. The mixture was extracted three times with ethyl acetate, the organic phases were combined, dried with anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography using gradient elution. The volume ratio of petroleum ether to ethyl acetate in each eluent was 1:0, 10:1, 5:1 to 2:1, respectively, to obtain the dynamic crosslinking agent.

[0031] Preparation Example 5: The specific preparation method of the dynamic crosslinking agent includes the following steps: (1) Under nitrogen protection, 20g of selenium powder was added to 200g of deionized water, the temperature was lowered to 0℃, and 20g of sodium borohydride aqueous solution with a concentration of 1mol / L was added dropwise. The reaction temperature was controlled not to exceed 0℃ during the dropwise addition. After the dropwise addition was completed, 4g of tetrabutylammonium bisulfate was added, the room temperature was restored, and the reaction was stirred for 1.5h. Then, 278.62g of toluene solution of 4-chlorobutyryl chloride with a concentration of 1mol / L was added, and the reaction was continued for 9h. After the reaction was completed, the organic phase and the aqueous phase were separated by washing with sodium bicarbonate aqueous solution with a concentration of 5%. The organic phase was dried with anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation. Then, the fraction at 50℃ was collected by vacuum distillation to obtain γ-selenobutyrolactone. (2) Under nitrogen protection, 20g of γ-selenobutyrolactone and 27.73g of 6-amino-2-(aminomethyl)naphthalene were added to 200g of tetrahydrofuran, heated to 45℃, reacted for 2h, cooled to room temperature, and 400g of deionized water were added. The mixture was extracted three times with ethyl acetate, the organic phases were combined, dried with anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography using gradient elution. The volume ratio of petroleum ether to ethyl acetate in each eluent was 1:0, 10:1, 5:1 to 2:1, respectively, to obtain the dynamic crosslinking agent.

[0032] Preparation Example 6: A specific preparation method for a dynamic crosslinking agent, including the following steps: (1) Under nitrogen protection, 20g of selenium powder was added to 240g of deionized water, the temperature was lowered to 0℃, and 22g of sodium borohydride aqueous solution with a concentration of 1mol / L was added dropwise. The reaction temperature was controlled not to exceed 0℃ during the dropwise addition. After the dropwise addition was completed, 6g of tetrabutylammonium bisulfate was added, the room temperature was restored, and the reaction was stirred for 2h. Then, 303.95g of toluene solution of 4-chlorobutyryl chloride with a concentration of 1mol / L was added, and the reaction was continued for 12h. After the reaction was completed, the organic phase and the aqueous phase were separated by washing with 5% sodium bicarbonate aqueous solution. The organic phase was dried with anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation. Then, the fraction at 50℃ was collected by vacuum distillation to obtain γ-selenobutyrolactone. (2) Under nitrogen protection, 20g of γ-selenobutyrolactone and 30.04g of 6-amino-2-(aminomethyl)naphthalene were added to 240g of tetrahydrofuran, heated to 50℃, reacted for 3h, cooled to room temperature, and 500g of deionized water were added. The mixture was extracted three times with ethyl acetate, the organic phases were combined, dried with anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography using gradient elution. The volume ratio of petroleum ether to ethyl acetate in each eluent was 1:0, 10:1, 5:1 to 2:1, respectively, to obtain the dynamic crosslinking agent.

[0033] Comparative Preparation Example 1: The difference between Comparative Preparation Example 1 and Preparation Example 6 is that 6-amino-2-(aminomethyl)naphthalene is replaced with 4-aminobenzylamine.

[0034] Example 1: A specific preparation method of an ultra-high molecular weight polymer rope core: S1. Add 6 kg of maleic anhydride-grafted ultra-high molecular weight polyethylene prepared according to Preparation Example 1, 2 kg of amino-terminated nylon 6, 100 g of silicon copper powder and 50 g of antioxidant 1010 to a high-speed mixer and mix at high speed for 10 min at room temperature to obtain a premix. Add the premix to a twin-screw extruder and set the temperature as follows: Zone 1: 130°C, Zone 2: 170°C, Zone 3: 220°C, Zone 4: 230°C, Zone 5: 220°C, and screw speed: 70 rpm. In Zone 5 of the extruder, add 200 g of the dynamic crosslinking agent prepared according to Preparation Example 4. After water cooling and pelletizing, obtain blend masterbatch. S2. Add 5 kg of blending masterbatch to 20 kg of decahydronaphthalene, heat to 130℃, stir for 1.5 h, degas for 30 min to obtain a gel solution, and send the gel solution into a spinneret (spinneret orifice diameter 0.08 mm, number of orifices 40) via a spinning pump. Pre-stretch twice in air to form nascent fibers, and then put them into a decahydronaphthalene coagulation bath at 55℃ for 5 min to allow the solvent to precipitate, obtaining solidified fibers. Then pass them through a three-stage hot stretching machine with stretching temperatures set as follows: stage 1 75℃, stage 2 115℃, stage 3 135℃, with stretching ratios of 2 times, 2 times, and 1.5 times for each stage, to obtain rope core monofilaments; S3. The core monofilaments are braided using a braiding machine, with alternating twists in the Z and S directions, and a braiding density of 80 meshes / inch to obtain the core blank. Finally, it is placed in a vacuum drying oven for shaping to eliminate braiding internal stress and obtain the ultra-high molecular weight rope core.

[0035] Example 2: A specific preparation method for an ultra-high molecular weight polymer rope core: S1. Add 6.5 kg of maleic anhydride-grafted ultra-high molecular weight polyethylene prepared according to Preparation Example 2, 2.5 kg of amino-terminated nylon 6, 150 g of silicon copper powder and 100 g of antioxidant 1010 to a high-speed mixer and mix at high speed for 15 min at room temperature to obtain a premix. Add the premix to a twin-screw extruder and set the temperature as follows: Zone 1: 140°C, Zone 2: 180°C, Zone 3: 230°C, Zone 4: 240°C, Zone 5: 225°C, and screw speed: 80 rpm. In Zone 5 of the extruder, add 300 g of the dynamic crosslinking agent prepared according to Preparation Example 5. After water cooling and pelletizing, obtain blend masterbatch. S2. Add 5 kg of blending masterbatch to 25 kg of decahydronaphthalene, heat to 135℃, stir for 2 h, degas for 30 min to obtain a gel solution, and send the gel solution into a spinneret (1 mm orifice, 50 orifices) via a spinning pump. Pre-stretch 3 times in air to form nascent fibers, and then put them into a 60℃ decahydronaphthalene coagulation bath for 8 min to allow the solvent to precipitate, obtaining solidified fibers. Then, pass them through a three-stage hot stretching machine with stretching temperatures set as follows: stage 1 80℃, stage 2 120℃, stage 3 140℃, with stretching ratios of 2.5 times, 2.5 times, and 1.8 times for each stage, to obtain a total of rope core monofilaments. S3. The core monofilaments are braided using a braiding machine, with alternating twists in the Z and S directions, and a braiding density of 100 meshes / inch to obtain the core blank. Finally, it is placed in a vacuum drying oven for shaping to eliminate braiding internal stress and obtain the ultra-high molecular weight rope core.

[0036] Example 3: A specific preparation method for an ultra-high molecular weight polymer rope core: S1. Add 7 kg of maleic anhydride-grafted ultra-high molecular weight polyethylene prepared according to Preparation Example 3, 3 kg of amino-terminated nylon 6, 200 g of silicon copper powder and antioxidant 168 to a high-speed mixer and mix at high speed for 20 min at room temperature to obtain a premix. Add the premix to a twin-screw extruder and set the temperature as follows: Zone 1: 150°C, Zone 2: 190°C, Zone 3: 240°C, Zone 4: 250°C, Zone 5: 230°C, and screw speed: 90 rpm. In Zone 5 of the extruder, add 400 g of the dynamic crosslinking agent prepared according to Preparation Example 6. After water cooling and pelletizing, obtain blend masterbatch. S2. Add 5 kg of blending masterbatch to 30 kg of decahydronaphthalene, heat to 140℃, stir for 2.5 h, degas for 30 min to obtain a gel solution, and send the gel solution into a spinneret (0.12 mm orifice, 60 orifices) via a spinning pump. Pre-stretch 4 times in air to form nascent fibers, and then put them into a 65℃ decahydronaphthalene coagulation bath for 10 min to allow the solvent to precipitate, obtaining solidified fibers. Then, pass them through a three-stage hot stretching machine with stretching temperatures set as follows: stage 1 85℃, stage 2 125℃, stage 3 145℃, and stretching ratios of 3 times, 3 times, and 2 times for each stage, to obtain rope core monofilaments. S3. The core monofilaments are braided using a braiding machine, with alternating twists in the Z and S directions, and a braiding density of 120 meshes / inch to obtain the core blank. Finally, it is placed in a vacuum drying oven for shaping to eliminate braiding internal stress and obtain the ultra-high molecular weight rope core.

[0037] Comparative Example 1: The difference between Comparative Example 1 and Example 3 is that the dynamic crosslinking agent prepared according to Preparation Example 6 is replaced with the dynamic crosslinking agent prepared according to Comparative Preparation Example 1.

[0038] Comparative Example 2: The difference between Comparative Example 2 and Example 3 is that maleic anhydride-grafted ultra-high molecular weight polyethylene is replaced with ultra-high molecular weight polyethylene.

[0039] Comparative Example 3: The difference between Comparative Example 3 and Example 3 is that the terminal amino-terminated nylon 6 is replaced with nylon 6.

[0040] Comparative Example 4: The difference between Comparative Example 4 and Example 3 is that no dynamic crosslinking agent is added.

[0041] Performance testing: The ultra-high polymer rope cores prepared in Examples 1-3 and Comparative Examples 1-4 were used to prepare a composite material tendon rope for robots according to the following steps: Metal wires are evenly wrapped around the outside of the ultra-high molecular weight polymer rope core by twisting multiple strands. Multiple bundles of metal wires are radially woven around the central rope core to form a composite structure of a central rope core and an outer reinforcing layer. The woven tendon rope is placed in an environment of 80-120℃ for 1-2 hours to eliminate weaving stress, thus obtaining a composite material tendon rope for robots.

[0042] 1. Axial tensile strength test: Referring to GB / T 1447-2005 "Test Method for Tensile Properties of Fiber Reinforced Plastics", the ultra-high molecular weight rope cores (200 mm in length) prepared in Examples 1-3 and Comparative Examples 1-4 were selected as test samples. A universal testing machine was used, with the tensile speed set to 5 mm / min and the clamping distance to 100 mm. Axial tension was applied uniformly until the sample broke. The elongation at break was recorded, and the tensile strength was calculated (tensile strength = maximum load / sample cross-sectional area). The experimental results are shown in Table 1.

[0043] 2. Creep resistance test: Referring to GB / T 17604-2008 "Determination of tensile creep properties of plastics", the ultra-high molecular weight rope cores of Examples 1-3 and Comparative Examples 1-4 were used as test objects (sample length 150 mm, cross-sectional area calculated according to actual measurement). The test environment temperature was set to 50℃ (simulating the working temperature after heat dissipation of robot motor). A constant axial load (30% of the tensile strength of the sample) was applied. The deformation of the sample at 0h, 24h, 48h and 72h was recorded in real time using a displacement sensor. The creep rate was calculated (creep rate = (deformation at a certain time point - initial deformation) / initial length × 100%). The experimental results are shown in Table 1.

[0044] 3. Fatigue Resistance Test: Referring to GB / T 35465-2017 "Test Methods for Fatigue Properties of Plastics and Composite Materials", the finished robot tendon ropes (250mm in length) from Examples 1-3 and Comparative Examples 1-4 were selected as test samples. A fatigue testing machine was used, set to axial reciprocating tensile mode, with a loading frequency of 10Hz (simulating the high-frequency opening and closing condition of a humanoid robot finger). The maximum load was 20% of the sample's tensile strength, the minimum load was 5% of the maximum load, and the number of cycles was set to 10. 6 After each cycle, the tensile strength of the sample was tested again, and the strength retention rate was calculated (strength retention rate = tensile strength after fatigue / initial tensile strength × 100%). The experimental results are shown in Table 1.

[0045] 4. Interface compatibility test: The cross-sectional morphology of the ultra-high molecular weight rope cores of Examples 1-3 and Comparative Examples 1-4 after tensile fracture was observed under a microscope. The microstructure of the cross-section was observed and the fracture morphology was determined: ductile fracture was fiber pull-out and brittle fracture was a flat cross-section. The experimental results are shown in Table 1.

[0046] 5. Low-temperature impact toughness test: Referring to GB / T 1043.1-2008 "Determination of impact properties of simply supported beams of plastics - Part 1: Non-instrumental impact test", the ultra-high molecular weight rope cores of Examples 1-3 and Comparative Examples 1-4 were used as test samples. The samples were cut into standard strips with a length of 80 mm, a width of 10 mm, and a thickness of 2 mm. They were placed in a low-temperature environment of -20℃ for 2 hours (simulating outdoor or cold chain conditions). A simply supported beam impact testing machine was used, with the pendulum energy set to 2 J and the impact velocity to 3.5 m / s. The low-temperature strips were subjected to impact tests, and the impact absorption energy was recorded. The impact toughness was calculated (impact toughness = impact absorption energy / cross-sectional area of ​​the strip). The experimental results are shown in Table 1.

[0047] 6. Abrasion resistance test of finished tendon chords: Referring to GB / T 3960-2016 "Test Method for Sliding Friction and Wear of Plastics", the finished robot tendon chords (200mm in length) of Examples 1-3 and Comparative Examples 1-4 were used as test samples. A reciprocating abrasion tester was used, with 45# steel as the friction pair (simulating the metal pulley of the robot joint). The loading pressure was set to 5N, the reciprocating frequency to 2Hz, the reciprocating stroke to 50mm, and the total number of friction cycles to 1×10⁻⁶. 4 After the experiment, the mass of the sample before and after wear was weighed using an electronic balance (accuracy 0.1 mg), and the wear amount was calculated (wear amount = mass before wear - mass after wear). The experimental results are shown in Table 1.

[0048] Table 1 Performance Test Results

[0049] Performance Analysis: As can be seen from the experimental data in Table 1, the ultra-high molecular weight rope core and the composite tendon rope for robots prepared in the embodiments of the present invention, relying on the synergistic effect of maleic anhydride-grafted ultra-high molecular weight polyethylene (PE-g-MAH) and amino-terminated nylon 6, the crosslinking network containing diselenyl bond dynamic crosslinking agent, and the multi-strand alternating braiding structure, comprehensively outperforms the comparative examples in core properties such as axial tensile strength, creep resistance, and fatigue resistance; among them, Example 3 has the best comprehensive performance.

[0050] Example 3 exhibits the best axial tensile strength, primarily due to the synergistic effect of a triple mechanism: the molecular chain framework of PE-g-MAH, a highly cross-linked dynamic network, and dense weaving for stress transfer. At the molecular level, the PE-g-MAH used in Example 3, prepared with the longest reaction time (6 hours) and the highest amount of maleic anhydride, likely has a higher grafting rate of anhydride groups. This allows for a thorough reaction with the primary amino groups of terminal amino-terminated nylon 6 to generate stable amide bonds, tightly anchoring the non-polar high-molecular-weight polyethylene to polar nylon 6 and preventing slippage between molecular chains. Simultaneously, the dynamic cross-linking agent added in Example 3 contains diselenyl bonds, which can further cross-link different high-molecular-weight polyethylene molecular chains, forming a "amide bond-diselenyl bond" dual covalent network, significantly enhancing the bonding force between molecular chains. Structurally, Example 3 has the highest weaving density and the largest total elongation. Multiple strands of monofilament form a uniform stress transfer channel under alternating twisting, allowing axial loads to be evenly distributed through inter-filament friction and radial extrusion, preventing localized overload fracture. In comparison, all comparative examples show lower strength than Example 3: Comparative Example 1, due to the dynamic cross-linking... The crosslinking agent was replaced with 4-aminobenzylamine, which lacked the naphthalene ring conjugated structure of 6-amino-2-(aminomethyl)naphthalene. This reduced the stability of the diselenide bond, decreased the crosslinking density, and prevented the formation of a dense molecular chain crosslinking network, thus weakening the resistance to molecular chain slippage. In Comparative Example 2, pure high molecular weight polyethylene was used to replace PE-g-MAH. The lack of anhydride groups prevented the formation of amide bonds with the terminal amino nylon 6, resulting in severe phase separation between the two polymers. Under stress, interfacial delamination easily occurred, and they could not cooperate in bearing the load. In Comparative Example 3, ordinary nylon 6 was used to replace the terminal amino nylon 6. Due to the absence of primary amino groups, it could not undergo a grafting reaction with PE-g-MAH. The interfacial bonding force was extremely weak, and the load was borne only by the single chain of high molecular weight polyethylene, making it prone to monofilament breakage. In Comparative Example 4, no dynamic crosslinking agent was added, and the "molecular chain bridging" effect of the diselenide bond was missing. The constraint was only provided by the crystalline region of nylon 6, resulting in weak inter-chain bonding force and an inability to resist chain slippage under high loads.

[0051] Example 3 exhibits the best elongation at break, likely because it undergoes the highest degree of three-stage thermal stretching, resulting in an extremely high molecular weight polyethylene (MWPE) molecular chain orientation factor. This leads to a more regular axial alignment of the molecular chains and a significant reduction in lateral slip space. Simultaneously, the amide-bonded nylon 6 crystalline regions can "anchor" the MWPE flexible segments through intermolecular forces, while the diselenate crosslinking network further locks the molecular chain movement, preventing large deformations caused by free chain extension. Furthermore, the densest weave structure further restricts overall deformation through friction between filaments and radial compression, ultimately achieving a balance between low elongation and high stability. The elongation characteristics of all comparative examples cannot match the precision and strength synergy of Example 3: Comparative Example 1, due to dynamic crosslinking… The agent's stability is insufficient, and the locking effect of diselenide bonds on the molecular chain is weaker than in Example 3. The molecular chain slippage space is slightly larger, and the elongation is higher than in Example 3, which easily leads to deviations between the command and the actual position. Although the elongation of Comparative Examples 2 and 3 is lower than that of Example 3, it is due to the severe phase separation of the two polymers. The molecular chains cannot deform in synergy and exhibit brittle slippage characteristics upon fracture, accompanied by a significant decrease in strength. This is an ineffective optimization of "low elongation but low performance" and cannot meet the robot's dual requirements of "high precision + high strength". Comparative Example 4 lacks a dynamic crosslinking agent and relies only on the physical constraints of the braided structure. It lacks the chemical locking of diselenide bonds on the molecular chain, and the molecular chain is prone to slight slippage along the axial direction. The elongation is higher than that of Example 3, and long-term use is prone to precision drift.

[0052] Example 3 exhibits the best creep resistance, likely because, under simulated conditions at 50°C, the diselenylene bonds in Example 3 continuously lock the ultra-high molecular weight polyethylene (UHMWPE) molecular chains through their dynamic reversibility. When the molecular chains show a tendency to slip due to long-term load, the diselenylene bonds absorb stress through slight breakage, followed by rapid recombination to restore the cross-linked structure, preventing chain slip accumulation. Simultaneously, the nylon 6 crystalline region is structurally stable at this temperature, further restricting the movement of UHMWPE chain segments through intermolecular hydrogen bonds. The dense braided structure also prevents excessive deformation of local chain segments due to stress concentration through mutual compression between monofilaments. All comparative examples demonstrate superior creep resistance. The creep performance of Comparative Example 1 was far lower than that of Example 3. Due to the absence of the naphthalene ring conjugated structure in the dynamic crosslinking agent, the dynamic stability of the diselenide bond decreased, the recombination rate after breakage under stress slowed down, and the molecular chain slippage could not be locked in time, resulting in a higher creep degree than Example 3. Comparative Example 2 and Comparative Example 3 had weak interfacial bonding due to phase separation, and the molecular chain was prone to slippage along the interface. Without the constraint of a dense chemical network to accumulate slippage, the creep degree was significantly higher than that of Example 3. Comparative Example 4 did not add a dynamic crosslinking agent and lacked the dynamic locking effect of the diselenide bond. It relied only on the static constraint of the nylon 6 crystalline region. Under long-term load, the molecular chain slippage gradually accumulated, resulting in the highest creep degree.

[0053] Example 3 exhibits the best fatigue resistance, likely because when the tendon ligament is subjected to 10Hz high-frequency reciprocating tension, the diselenide bonds in Example 3 can undergo reversible fracture with stress changes, absorbing and dissipating localized stress concentrations generated during fatigue and preventing microcrack initiation. During the stress relaxation phase, the diselenide bonds rapidly recombine to restore the integrity of the cross-linked network, preventing microcrack propagation. Simultaneously, the continuous matrix and dense braided structure formed by the high grafting rate can evenly distribute fatigue stress to each filament, preventing premature fracture of filaments due to localized overload. The fatigue resistance of all comparative examples is lower than that of Example 3. Example 3: In Comparative Example 1, the diselenide bond stability of the dynamic crosslinking agent was insufficient, resulting in reduced recombination efficiency after breakage. This made it impossible to dissipate fatigue stress in a timely manner, and microcracks were prone to gradual propagation, leading to a lower strength retention rate than in Example 3. In Comparative Examples 2 and 3, due to interfacial defects in phase separation, fatigue stress tended to concentrate at the interface, causing rapid initiation and penetration of microcracks, resulting in a significantly lower strength retention rate than in Example 3. In Comparative Example 4, no dynamic crosslinking agent was added, and the stress dissipation effect of the diselenide bond was missing. Fatigue stress was absorbed solely by the deformation of the molecular chain itself, which easily led to chain breakage, resulting in a lower strength retention rate than in Example 3.

[0054] Example 3 exhibited the best interfacial compatibility, with fracture exhibiting typical ductile fracture (fiber pull-out). This is because PE-g-MAH and amino-terminated nylon 6 form a molecular-level blend system through amide bonds. In Example 3, PE-g-MAH acts as an interfacial compatibility agent; its anhydride groups react completely with the amino groups of amino-terminated nylon 6, eliminating the polarity difference between the two polymers and allowing nylon 6 to be uniformly dispersed in the ultra-high molecular weight polyethylene matrix, forming a continuous and defect-free interface. Upon fracture under stress, the covalent bonds and intermolecular forces between molecular chains must be overcome, leading to fiber pull-out and demonstrating excellent interfacial bonding. All comparative examples showed inferior interfacial compatibility compared to Example 3. In Comparative Example 1, due to the slightly poor stability of the dynamic crosslinking agent, although it did not affect the grafting of PE-g-MAH and amino-terminated nylon 6, the auxiliary stabilizing effect of the crosslinking network on the interface was weakened, resulting in a lower degree of fiber pull-out upon fracture compared to Example 3. Example 3 exhibits quasi-ductile fracture; Comparative Example 2 uses pure ultra-high molecular weight polyethylene instead of PE-g-MAH, without the reaction of acid anhydride groups with amino groups, the two polymers undergo severe phase separation due to polarity differences, and there is no effective bonding force at the interface, resulting in a brittle fracture with a flat fracture surface; Comparative Example 3 uses ordinary nylon 6 instead of terminal amino nylon 6, without the reaction of primary amino groups with the acid anhydride of PE-g-MAH, there is obvious phase separation at the interface, and it also exhibits a flat fracture surface; Comparative Example 4 does not add a dynamic crosslinking agent. Although PE-g-MAH and terminal amino nylon 6 can be grafted, the lack of a crosslinking network further stabilizes the interface, the interfacial bonding force is weaker than that of Example 3, and a flat fracture surface appears locally during fracture.

[0055] Example 3 exhibits the best low-temperature impact toughness, the mechanism of which lies in the effective preservation of flexible chain segment synergy, dynamic bond energy dissipation, and interfacial bonding stability at low temperatures. In a -20°C environment, the ultra-high molecular weight polyethylene flexible long chains in Example 3 still maintain a certain degree of chain segment mobility, and the flexible chains of nylon 6 can absorb impact energy through molecular torsion. Simultaneously, the diselenide bonds retain reversible fracture capability at low temperatures, dissipating impact stress through bond breakage and avoiding brittle fracture caused by stress concentration. Furthermore, the excellent interfacial bonding between PE-g-MAH and amino-terminated nylon 6 allows for efficient intermolecular transfer of impact energy, rather than concentration at interfacial defects, ultimately maintaining high impact toughness. All comparative examples show lower low-temperature impact toughness than Example 3. 3: Comparative Example 1 suffers from insufficient stability of diselenide bonds in the dynamic crosslinking agent, resulting in decreased efficiency of breakage and recombination at low temperatures, weakened energy dissipation capacity, and lower impact toughness than Example 3. Comparative Examples 2 and 3 suffer from phase separation, further deterioration of interfacial bonding at low temperatures, and inability to transfer impact energy between molecules, only absorption through local chain breakage, resulting in significantly lower impact toughness than Example 3. Comparative Example 4 does not contain a dynamic crosslinking agent, lacking the low-temperature energy dissipation effect of diselenide bonds, and relies solely on the segmental deformation of ultra-high molecular weight polyethylene and nylon 6 to absorb energy, resulting in weaker energy dissipation capacity and lower impact toughness than Example 3.

[0056] Example 3 shows the best abrasion resistance in the finished tendon rope. From the core perspective, the dense chemical network and highly oriented structure of the rope core in Example 3 result in extremely high dimensional stability, making it less prone to localized deformation during friction and preventing the polymer core from being exposed due to deformation and compression. From the outer layer perspective, the densely woven core of Example 3 provides uniform support for the metal wires. The metal wires are tightly woven radially around the core, forming a continuous physical protective layer that directly resists friction with the 45# steel pulley, reducing direct contact between the rope core and the metal. Simultaneously, the tight bond between the rope core and the metal wires prevents misalignment of the metal wires during friction, further reducing wear. All of these factors contribute to the superior abrasion resistance of the tendon rope. The wear resistance of the comparative examples was lower than that of Example 3: Comparative Example 1 had slightly poor dimensional stability due to insufficient cross-linking network stability of the rope core, and the rope core was prone to slight deformation during friction, resulting in loose adhesion of the metal wires in some areas, and the wear degree was higher than that of Example 3; Comparative Examples 2 and 3 had unstable dimensions due to phase separation of the rope core, and the rope core was prone to local indentation during friction, causing the metal wires to lose support and slide relative to the rope core, and the wear degree was significantly higher than that of Example 3; Comparative Example 4 had no cross-linking network in the rope core, and long-term friction easily caused creep, resulting in loosening of the metal wire coating, and the metal pulley directly contacting a local area of ​​the rope core, and the wear degree was the highest.

[0057] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A type of ultra-high molecular weight rope core, characterized in that, The raw materials include the following parts by weight: maleic anhydride-grafted ultra-high molecular weight polyethylene: 60-70 parts, amino-terminated nylon 6: 20-30 parts, dynamic crosslinking agent: 2-4 parts, silicon copper powder: 1-2 parts, antioxidant: 0.5-1.5 parts; The preparation method of the maleic anhydride-grafted ultra-high molecular weight polyethylene is as follows: Ultra-high molecular weight polyethylene powder was ultrasonically cleaned with ethanol for 10-20 min, dried, added to xylene and benzoyl peroxide, purged with nitrogen three times, heated to 70-90℃, and maleic anhydride was added under stirring. The reaction was carried out for 4-6 h, xylene was removed by filtration, the obtained solid was washed with ethanol, then extracted with acetone by Soxhlet for 24 h and dried to obtain maleic anhydride-grafted ultra-high molecular weight polyethylene. The preparation method of the dynamic crosslinking agent is as follows: (1) Under nitrogen protection, selenium powder was added to deionized water and cooled to 0°C. A 1 mol / L sodium borohydride aqueous solution was added dropwise, and the reaction temperature was controlled not to exceed 0°C during the dropwise addition. After the dropwise addition was completed, tetrabutylammonium bisulfate was added, the room temperature was restored, and the reaction was stirred for 1-2 h. Then, a toluene solution of 4-chlorobutyryl chloride was added, and the reaction was continued for 6-12 h. After the reaction was completed, the mixture was washed with a 5% sodium bicarbonate aqueous solution to separate the organic phase and the aqueous phase. The organic phase was dried with anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation. Then, the fraction at 50°C was collected by vacuum distillation to obtain γ-selenobutyrolactone. (2) Under nitrogen protection, γ-selenobutyrolactone and 6-amino-2-(aminomethyl)naphthalene were added to tetrahydrofuran, heated to 40-50℃, reacted for 1-3 h, cooled to room temperature, deionized water was added, and the mixture was extracted three times with ethyl acetate. The organic phases were combined, dried with anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography using gradient elution to obtain the dynamic crosslinking agent.

2. The ultra-high molecular weight polymer rope core according to claim 1, characterized in that, The antioxidant is one of antioxidant 1010 or antioxidant 168.

3. The ultra-high molecular weight polymer rope core according to claim 1, characterized in that, In the method for preparing maleic anhydride-grafted ultra-high molecular weight polyethylene, the average molecular weight of the ultra-high molecular weight polyethylene is greater than or equal to 10. 6 .

4. The ultra-high molecular weight polymer rope core according to claim 1, characterized in that, In the method for preparing maleic anhydride-grafted ultra-high molecular weight polyethylene, ultra-high molecular weight polyethylene powder, xylene, benzoyl peroxide and maleic anhydride are in a weight ratio of 1:4-6:0.01-0.02:0.3-0.

5.

5. The ultra-high molecular weight polymer rope core according to claim 1, characterized in that, In (1), the molar ratio of selenium powder and 4-chlorobutyryl chloride is 1:1-1.2; the weight ratio of selenium powder, deionized water, sodium borohydride aqueous solution with a concentration of 1 mol / L and tetrabutylammonium bisulfate is 1:8-12:0.9-1.1:0.1-0.3, and the concentration of toluene solution of 4-chlorobutyryl chloride is 1 mol / L.

6. The ultra-high molecular weight polymer rope core according to claim 1, characterized in that, In step (2), the molar ratio of γ-selenobutyrolactone and 6-amino-2-(aminomethyl)naphthalene is 1:1.1-1.3; the weight ratio of γ-selenobutyrolactone, tetrahydrofuran and deionized water is 1:8-12:15-25; gradient elution refers to the volume ratio of petroleum ether and ethyl acetate in each eluent step from 1:0, 10:1, 5:1 to 2:

1.

7. The method for preparing the ultra-high molecular weight polymer rope core according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Maleic anhydride-grafted ultra-high molecular weight polyethylene, amino-terminated nylon 6, silicon copper powder, and antioxidant are added to a high-speed mixer and mixed at high speed for 10-20 minutes at room temperature to obtain a premix. The premix is ​​then added to a twin-screw extruder, with the following settings: Zone 1: 130-150℃, Zone 2: 170-190℃, Zone 3: 220-240℃, Zone 4: 230-250℃, Zone 5: 220-230℃, and screw speed: 70-90 rpm. In Zone 5 of the extruder, a dynamic crosslinking agent is added. The extrudate is then water-cooled and pelletized to obtain blend masterbatch. S2. Add the blending masterbatch to decahydronaphthalene, heat to 130-140℃, stir for 1.5-2.5h, degas for 30min to obtain a gel solution, send the gel solution into the spinneret via a spinning pump, pre-stretch 2-4 times in air to form nascent fibers, then enter a decahydronaphthalene coagulation bath at 55-65℃, soak for 5-10min to allow solvent precipitation, obtain solidified fibers, then pass through a three-stage hot stretching machine, with stretching temperatures set as follows: stage 1 75-85℃, stage 2 115-125℃, stage 3 135-145℃, with stretching ratios of 2-3 times, 2-3 times, and 1.5-2 times for each stage, to obtain rope core monofilaments; S3. The core monofilaments are braided using a braiding machine, with alternating twists in the Z and S directions, and a braiding density of 80-120 meshes / inch to obtain the core blank. Finally, it is placed in a vacuum drying oven for shaping to eliminate braiding internal stress and obtain the ultra-high molecular weight rope core.

8. The method for preparing the ultra-high molecular weight rope core according to claim 7, characterized in that, The S2 co-blended masterbatch and decahydronaphthalene are in a weight ratio of 1:4-6; the spinneret has an orifice diameter of 0.08-0.12 mm and a number of orifices of 40-60.

9. A composite material tendon rope for robots, made from the ultra-high molecular weight polymer rope core as described in any one of claims 1-6, characterized in that, Includes the following steps: The outer reinforcing fiber is evenly wrapped around the outside of the ultra-high molecular weight rope core by twisting multiple strands. Multiple bundles of fibers are radially woven around the central rope core to form a composite structure of central rope core and outer reinforcing layer. The woven tendon rope is placed in an environment of 80-120℃ for 1-2 hours to eliminate weaving stress, thus obtaining a composite material tendon rope for robots.

10. The composite material tendon chord for robots according to claim 9, characterized in that, The outer reinforcing fiber refers to a metal wire, including either steel wire or tungsten wire.

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