A tensile-resistant composite cable for a robot and a method of manufacturing the same

Abstract

The application discloses a kind of tensile composite cable for robot and preparation method thereof, belong to the technical field of robot cable.The inside to outside includes successively: conductive core layer, insulating layer, tensile reinforcing layer, electromagnetic shielding layer and outer sheath layer, wherein the material of outer sheath layer includes the following weight parts of raw materials: 75-87 parts of ethylene-propylene-diene rubber, 11-17 parts of hydrophobic aluminum oxide, 3-9 parts of functional additives, 2-5 parts of processing aids and 0.05-0.15 parts of initiator.Hydrophobic aluminum oxide can reduce the risk of matrix cracking, and enhance the tensile properties of cable;The functional additives contain nitrogen, phosphorus and other flame-retardant groups and rigid benzene ring structure in the molecular structure, which can not only improve the flame retardance of the cable, but also improve the tensile properties and heat resistance of the cable;In summary, the cable prepared by the application has excellent tensile resistance, flame retardance and heat resistance, and can work in high temperature environment, and has important application value in the field of robot cable technology.

Description

Technical Field

[0001] This invention belongs to the field of robot cable technology, specifically, it relates to a tensile composite cable for robots and its preparation method. Background Technology

[0002] With the rapid development of robotics technology, robots are increasingly widely used in numerous industries such as industrial production, service sectors, healthcare, and the military. The normal operation of a robot depends on the coordinated work of various functional components. Among these, cables, as key components for transmitting electrical energy and signals within the robot, have a significant impact on the robot's stability, reliability, and lifespan. During the robot's operation, cables often need to bend, stretch, and twist continuously following the robot's joint movements, which places extremely high demands on the cables' tensile strength.

[0003] Traditional robot cables have many shortcomings in terms of tensile strength. Some ordinary cables consist of only a simple conductor and insulation layer. When subjected to tensile force, the conductor is prone to breakage and deformation, which affects the transmission of electrical energy and signals, causing robot malfunctions or even preventing normal operation. Even though some cables use filler materials to improve tensile strength, while ordinary filler materials can reduce the relative displacement of internal components under tension to some extent, the poor compatibility between the filler material and the cable substrate means that the effect is still not satisfactory.

[0004] Furthermore, robots often operate in complex environments, and in addition to tensile forces, cables may also be affected by high temperatures. Some existing tensile cables are prone to thermal aging at high temperatures. Therefore, it is urgent to solve these problems to meet the higher demands of the robot cable technology field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a tensile composite cable for robots and a method for preparing the same.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A tensile composite cable for robots comprises, from the inside out: a conductive core layer, an insulation layer, a tensile reinforcement layer, an electromagnetic shielding layer, and an outer sheath layer.

[0008] As a further technical solution, the conductive core layer is made of stranded copper wire with a single wire diameter of 0.08 mm and a stranding pitch ratio of 12-15 times.

[0009] As a further technical solution, the insulating layer is made of polypropylene.

[0010] As a further technical solution, the tensile reinforcement layer is made of ultra-high molecular weight polyethylene fiber.

[0011] As a further technical solution, the material of the electromagnetic shielding layer is a silver-plated copper wire braided mesh.

[0012] As a further technical solution, the material of the outer sheath layer includes the following raw materials in parts by weight: 75-87 parts EPDM rubber, 11-17 parts hydrophobic alumina, 3-9 parts functional additives, 2-5 parts processing aids, and 0.05-0.15 parts initiator.

[0013] As a further technical solution, the processing aid is one of stearic acid, glyceryl monostearate, polyethylene wax, and oleamide.

[0014] As a further technical solution, the initiator is one of benzoyl peroxide and dicumyl peroxide.

[0015] As a further technical solution, the hydrophobic alumina is prepared by the following steps:

[0016] A1. Dry the alumina powder at 100-150℃ for 2-4 hours to remove surface adsorbed water and enhance surface activity, thereby obtaining dried alumina powder.

[0017] A2. Dissolve isopropyl triisostearic acid titanate in anhydrous ethanol, stir evenly, then add the dry alumina powder obtained in step A1, and ultrasonically disperse at 40-70℃ for 0.5-2h to allow the titanate to be adsorbed on the surface. After the reaction is complete, filter and dry to obtain hydrophobic alumina.

[0018] As a further technical solution, the ratio of the alumina powder, isopropyl triisostearate titanate, and anhydrous ethanol is 10g:0.3-0.5g:100mL.

[0019] This invention uses a titanate coupling agent to modify alumina. The titanate coupling agent molecule contains inorganic-loving titanate groups and organic-loving long-chain alkyl groups, which combine with hydroxyl groups on the surface of alumina. The alkyl chains are arranged outward to form a hydrophobic layer. At the same time, it can entangle with the polymer matrix, which greatly enhances the compatibility between alumina and EPDM rubber matrix. Since alumina is a rigid filler, it disperses the tensile load to the filler particles through the "stress transfer effect", reducing the risk of matrix cracking. After hydrophobic modification, the tensile properties of the matrix can be greatly enhanced.

[0020] As a further technical solution, the functional additive is prepared through the following steps:

[0021] Step B1: In a four-necked flask equipped with a thermometer, a constant-pressure dropping funnel, a magnetic stirrer, and a reflux condenser, add 1,5-naphthyldiamine, triethylamine, and toluene. Stir magnetically for 10-20 min. Then, add allyl chloride dropwise to the flask through the constant-pressure dropping funnel. After stirring evenly, introduce nitrogen gas into the apparatus and place it in a 50°C water bath. Reflux the reaction for 6-8 h. After the reaction is complete, cool to room temperature, filter, distill under reduced pressure, and purify by column chromatography (petroleum ether / ethyl acetate = 3:1) to obtain reaction product A.

[0022] The reaction principle of step B1 is as follows: triethylamine acts as an acid-binding agent, catalyzing the nucleophilic substitution reaction between 1,5-naphthyldiamine and allyl chloride, with a slight excess of 1,5-naphthyldiamine to reduce the occurrence of side reactions in the production of the disubstituted product; the reaction formula is as follows:

[0023]

[0024] Step B2: In a four-necked flask equipped with a thermometer, magnetic stirrer, and condenser, add reaction product A, triethylamine, and toluene. Stir magnetically for 10-20 minutes. Then add phenylphosphine dichloride to the beaker and stir until well mixed. Purge nitrogen gas into the apparatus and place it in a water bath at 60°C. Keep the reaction at this temperature for 6-8 hours. After the reaction is complete, cool to room temperature, filter, remove some of the solvent by rotary evaporation, and purify by column chromatography (petroleum ether / ethyl acetate = 4:1) to obtain reaction product B.

[0025] The reaction principle in step B2 is as follows: Triethylamine acts as an acid-binding agent, catalyzing the nucleophilic substitution reaction between reaction product A and phenylphosphine dichloride, with a slight excess of phenylphosphine dichloride to reduce the occurrence of side reactions; the reaction formula is as follows:

[0026]

[0027] Step B3: In a four-necked flask equipped with a thermometer, magnetic stirrer, and condenser, add reaction product B, 3,5-diamino-1,2,4-triazole, triethylamine, and toluene. After mixing evenly with magnetic stirring, introduce nitrogen gas into the apparatus and place it in an oil bath at 70°C. Maintain the temperature for 8-12 hours. After the reaction is complete, cool to room temperature, filter, remove some solvent by rotary evaporation, and purify by column chromatography (petroleum ether / ethyl acetate = 5:1) to obtain the functional additive.

[0028] The reaction principle of step B3 is as follows: Triethylamine acts as an acid-binding agent, catalyzing the nucleophilic substitution reaction between reaction product B and 3,5-diamino-1,2,4-triazole, with a molar ratio of 2:1 (reaction product B is slightly in excess), ensuring that both amino groups in 3,5-diamino-1,2,4-triazole participate in the reaction; the structure of the functional adjuvant is shown below:

[0029]

[0030] This invention prepares functional additives through a simple and identical three-step nucleophilic substitution reaction. The functional additive molecules contain triazole, a benzene ring, unsaturated double bonds, and a PN flame-retardant component. Triazole is a five-membered heterocyclic structure containing three nitrogen atoms. These nitrogen atoms form a stable aromatic structure through a conjugated system. Furthermore, the CN and NN bonds in the triazole ring have high bond energies, making them difficult to break and improving the heat resistance of the matrix. In addition, the functional additive molecules contain a large number of benzene ring structures. Benzene rings are rigid structures that improve the tensile strength of the matrix, and their unique co-... The π-electron system and molecular structure stability make it less prone to breakage or decomposition at high temperatures, further improving the heat resistance of the matrix. Moreover, the unsaturated double bonds in the functional additive molecules can undergo cross-linking reactions with the unsaturated double bonds in the side chains of EPDM rubber under the action of the initiator, further improving the tensile strength of the matrix and enhancing the migration and exudation resistance of the small molecule functional additives. Finally, the functional additives contain multiple PN synergistic flame retardant components, which have better flame retardant performance than single phosphorus and nitrogen-based flame retardants, significantly improving the flame retardant performance of the matrix.

[0031] As a further technical solution, the ratio of the amounts of 1,5-naphthyldiamine, triethylamine, toluene, and allyl chloride in step B1 is 16.1-16.8g:10.1g:100mL:7.6g.

[0032] As a further technical solution, the ratio of reaction product A, triethylamine, toluene, and phenylphosphine dichloride in step B2 is 19.8g:10.1g:120mL:20.1-21.9g.

[0033] As a further technical solution, in step B3, the ratio of reaction product B, 3,5-diamino-1,2,4-triazole, triethylamine, and toluene is 68.3-69.7g:9.7g:20.2g:200mL.

[0034] This invention also proposes a method for preparing tensile composite cables for robots, comprising the following steps:

[0035] Copper wires are twisted together to form a conductive core layer. Polypropylene is then extruded through a twin-screw extruder to coat the conductive core layer, forming an insulating layer. Ultra-high molecular weight polyethylene fibers are woven into a mesh structure using a high-speed braiding machine to cover the insulating layer, forming a tensile reinforcement layer. Silver-plated copper wire is then used to weave a mesh around the tensile reinforcement layer, forming an electromagnetic shielding layer. Finally, the material of the outer sheath layer is extruded through a twin-screw extruder to coat the surface of the electromagnetic shielding layer. After vulcanization, a tensile composite cable for robots is obtained.

[0036] The beneficial effects of this invention are:

[0037] 1. This invention uses ultra-high molecular weight polyethylene fiber woven mesh as a tensile reinforcement layer, which significantly improves the tensile strength of the cable and enables it to withstand the complex motion requirements of frequent bending, stretching and twisting of the robot.

[0038] 2. Adding hydrophobic alumina as a filler to the outer sheath layer can reduce the risk of substrate cracking and further enhance the tensile strength of the cable;

[0039] 3. The outer sheath layer uses EPDM rubber as the base material, which has excellent high temperature resistance and can adapt to the robot's operation in high temperature environments;

[0040] 4. Functional additives synthesized through a three-step nucleophilic substitution reaction contain flame-retardant groups such as nitrogen and phosphorus and rigid benzene ring structures in their molecular structure, which can not only improve the flame retardancy of cables, but also improve the tensile strength and heat resistance of cables.

[0041] In summary, the cable produced by this invention has excellent tensile strength, flame retardancy, and heat resistance, and can adapt to working in high-temperature environments, thus possessing significant application value in the field of robot cable technology. Detailed Implementation

[0042] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0043] Example 1

[0044] Preparation of functional additives:

[0045] Step B1: In a four-necked flask equipped with a thermometer, a constant-pressure dropping funnel, a magnetic stirrer, and a reflux condenser, add 16.1 g of 1,5-naphthyldiamine, 10.1 g of triethylamine, and 100 mL of toluene. Stir magnetically for 10 min. Then, add 7.6 g of allyl chloride dropwise to the flask through the constant-pressure dropping funnel. After stirring evenly, purge the apparatus with nitrogen gas and place it in a water bath at 50 °C. Reflux the reaction for 6 h. After the reaction is complete, cool to room temperature, filter, distill under reduced pressure, and purify by column chromatography (petroleum ether / ethyl acetate = 3:1) to obtain reaction product A.

[0046] Step B2: In a four-necked flask equipped with a thermometer, magnetic stirrer, and condenser, add 39.6 g of reaction product A, 20.2 g of triethylamine, and 240 mL of toluene. Stir magnetically for 10 min. Then add 40.2 g of phenylphosphine dichloride to a beaker and stir until well mixed. Purge nitrogen gas into the apparatus and place it in a water bath at 60 °C. Keep the reaction at this temperature for 6 h. After the reaction is complete, cool to room temperature, filter, remove some of the solvent by rotary evaporation, and purify by column chromatography (petroleum ether / ethyl acetate = 4:1) to obtain reaction product B.

[0047] Step B3: In a four-necked flask equipped with a thermometer, magnetic stirrer, and condenser, add 68.3g of reaction product B, 9.7g of 3,5-diamino-1,2,4-triazole, 20.2g of triethylamine, and 200mL of toluene. After mixing thoroughly with magnetic stirring, introduce nitrogen gas into the apparatus and place it in an oil bath at 70℃. Maintain the temperature for 8 hours until the reaction is complete. After cooling to room temperature, filter, remove some of the solvent by rotary evaporation, and purify by column chromatography (petroleum ether / ethyl acetate = 5:1) to obtain the functional additive.

[0048] Example 2

[0049] Preparation of functional additives:

[0050] Step B1: In a four-necked flask equipped with a thermometer, a constant-pressure dropping funnel, a magnetic stirrer, and a reflux condenser, add 16.8 g of 1,5-naphthyldiamine, 10.1 g of triethylamine, and 100 mL of toluene. Stir magnetically for 20 min. Then, add 7.6 g of allyl chloride dropwise to the flask through the constant-pressure dropping funnel. After stirring evenly, purge the apparatus with nitrogen gas and place it in a 50°C water bath. Reflux the reaction for 6-8 h. After the reaction is complete, cool to room temperature, filter, distill under reduced pressure, and purify by column chromatography (petroleum ether / ethyl acetate = 3:1) to obtain reaction product A.

[0051] Step B2: In a four-necked flask equipped with a thermometer, magnetic stirrer, and condenser, add 39.6 g of reaction product A, 20.2 g of triethylamine, and 240 mL of toluene. Stir magnetically for 10 min. Then add 43.8 g of phenylphosphine dichloride to a beaker and stir until well mixed. Purge nitrogen gas into the apparatus and place it in a water bath at 60 °C. Keep the reaction at this temperature for 6 h. After the reaction is complete, cool to room temperature, filter, remove some of the solvent by rotary evaporation, and purify by column chromatography (petroleum ether / ethyl acetate = 4:1) to obtain reaction product B.

[0052] Step B3: In a four-necked flask equipped with a thermometer, magnetic stirrer, and condenser, add 69.7g of reaction product B, 9.7g of 3,5-diamino-1,2,4-triazole, 20.2g of triethylamine, and 200mL of toluene. After mixing thoroughly with magnetic stirring, introduce nitrogen gas into the apparatus and place it in an oil bath at 70℃. Maintain the temperature for 12 hours. After the reaction is complete, cool to room temperature, filter, remove some of the solvent by rotary evaporation, and purify by column chromatography (petroleum ether / ethyl acetate = 5:1) to obtain the functional additive.

[0053] Example 3

[0054] Preparation of hydrophobic alumina:

[0055] A1. Dry 10g of alumina powder at 100℃ for 2h to remove surface adsorbed water and enhance surface activity, thereby obtaining dried alumina powder.

[0056] A2. Dissolve 0.3g of isopropyl triisostearic acid titanate in 100mL of anhydrous ethanol, stir evenly, then add the dry alumina powder obtained in step A1, and ultrasonically disperse at 40℃ for 2h to allow the titanate to be adsorbed on the surface. After the reaction is complete, filter and dry to obtain hydrophobic alumina.

[0057] Example 4

[0058] Preparation of hydrophobic alumina:

[0059] A1. Dry 10g of alumina powder at 150℃ for 4h to remove surface adsorbed water and enhance surface activity, thereby obtaining dried alumina powder.

[0060] A2. Dissolve 0.3g of isopropyl triisostearic acid titanate in 100mL of anhydrous ethanol, stir evenly, then add the dry alumina powder obtained in step A1, and ultrasonically disperse at 70℃ for 0.5h to allow the titanate to adsorb onto the surface. After the reaction is complete, filter and dry to obtain hydrophobic alumina.

[0061] Example 5

[0062] Materials used to prepare the outer sheath layer:

[0063] 75g of EPDM rubber, 11g of hydrophobic alumina prepared in Example 3, 3g of functional additives prepared in Example 1, 2g of stearic acid and 0.05g of benzoyl peroxide were melt-blended in a torque rheometer, and the melt blend was vulcanized in a flat vulcanizing machine to obtain the material of the outer sheath layer.

[0064] Example 6

[0065] Materials used to prepare the outer sheath layer:

[0066] 81g of EPDM rubber, 14g of hydrophobic alumina prepared in Example 4, 6g of functional additives prepared in Example 2, 4g of glyceryl monostearate and 0.1g of dicumyl peroxide were melt-blended in a torque rheometer, and the melt blend was vulcanized in a flat vulcanizing machine to obtain the material of the outer sheath layer.

[0067] Example 7

[0068] Materials used to prepare the outer sheath layer:

[0069] 87g of EPDM rubber, 17g of hydrophobic alumina prepared in Example 4, 9g of functional additives prepared in Example 2, 5g of oleamide and 0.15g of dicumyl peroxide were melt-blended in a torque rheometer, and the melt blend was vulcanized in a flat vulcanizing machine to obtain the material of the outer sheath layer.

[0070] Example 8

[0071] Copper wires are twisted together to form a conductive core layer. Polypropylene is then extruded through a twin-screw extruder to coat the conductive core layer, forming an insulating layer. Ultra-high molecular weight polyethylene fibers are woven into a mesh structure using a high-speed braiding machine to cover the insulating layer, forming a tensile reinforcement layer. Silver-plated copper wire is then used to weave a mesh around the tensile reinforcement layer, forming an electromagnetic shielding layer. Finally, 87g of EPDM rubber, 17g of hydrophobic alumina prepared in Example 4, 9g of functional additives prepared in Example 2, 5g of oleamide, and 0.15g of dicumyl peroxide are fed into a twin-screw extruder and extruded to coat the surface of the electromagnetic shielding layer. After vulcanization, a tensile composite cable for robots is obtained.

[0072] Comparative Example 1

[0073] The material was prepared by replacing the functional additive in Example 7 with a commercially available high-temperature resistant additive of the same quality, while the remaining steps were the same as in Example 7.

[0074] Comparative Example 2

[0075] The material was prepared by replacing the functional additives in Example 7 with commercially available phosphorus-based flame retardants of the same quality, with the remaining steps being the same as in Example 7.

[0076] Comparative Example 3

[0077] Use commercially available EPDM cable material.

[0078] Performance tests were conducted on Examples 5, 6, and 7, and Comparative Examples 1, 2, and 3:

[0079] The tensile strength was determined according to the national standard GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber";

[0080] The tensile strength of the specimens was tested after being placed in a high-temperature oven (150℃×72h) according to the national standard GB / T 3512-2014 "Accelerated Aging and Heat Resistance Test of Vulcanized Rubber or Thermoplastic Rubber in Hot Air". The tensile strength retention rate was calculated as follows: Tensile strength retention rate = tensile strength after test / tensile strength before test × 100%.

[0081] The oxygen index of the samples was determined according to the national standard GB / T 2406-2008 "Test Method for Burning Performance of Plastics";

[0082] The measurement results are shown in the table below:

[0083]

[0084] As can be seen from the table above, the embodiments of the present invention, compared with the comparative examples, show that the tensile strength of the embodiments is improved after adding the self-made functional additives of the present invention. Furthermore, the improvement in heat resistance and flame retardancy is higher than that of commercially available additives. Therefore, using the outer sheath material of the present invention in cables can also improve their corresponding performance, and has important application value in the field of robot cable technology.

[0085] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0086] The above description is merely an example and illustration of the present invention. Any modifications or additions made by those skilled in the art to the specific embodiments described, or any substitutions made in a similar manner, should fall within the protection scope of the present invention.

Claims

1. A tensile composite cable for robots, comprising, from the inside out: The conductive core layer, insulating layer, tensile reinforcement layer, electromagnetic shielding layer, and outer sheath layer are characterized in that the material of the outer sheath layer comprises the following raw materials in parts by weight: 75-87 parts EPDM rubber, 11-17 parts hydrophobic alumina, 3-9 parts functional additives, 2-5 parts processing aids, and 0.05-0.15 parts initiator; The functional additive is prepared through the following steps: Step B1: In a flask, add 1,5-naphthyldiamine, triethylamine and toluene, stir, then add allyl chloride dropwise, stir until homogeneous, then purge with nitrogen gas and reflux at 50°C for 6-8 hours. Once the reaction is complete, product A is obtained. Step B2: In a flask, add reaction product A, triethylamine and toluene, stir, then add phenylphosphine dichloride, stir evenly, then purge with nitrogen gas and react at 60°C for 6-8 hours. The reaction is complete, and reaction product B is obtained. Step B3: In a flask, add reaction product B, 3,5-diamino-1,2,4-triazole, triethylamine and toluene, stir well, then introduce nitrogen gas and react at 70°C for 8-12 hours. Once the reaction is complete, the functional additive is obtained.

2. The tensile composite cable for robots according to claim 1, characterized in that, In step B1, the ratio of the amounts of 1,5-naphthyldiamine, triethylamine, toluene, and allyl chloride is 16.1-16.8 g: 10.1 g: 100 mL: 7.6 g.

3. The tensile composite cable for robots according to claim 1, characterized in that, In step B2, the ratio of reaction product A, triethylamine, toluene, and phenylphosphine dichloride is 19.8 g: 10.1 g: 120 mL: 20.1-21.9 g.

4. The tensile composite cable for robots according to claim 1, characterized in that, In step B3, the ratio of reaction product B, 3,5-diamino-1,2,4-triazole, triethylamine, and toluene is 68.3-69.7 g: 9.7 g: 20.2 g: 200 mL.

5. A tensile composite cable for robots according to claim 1, characterized in that, The hydrophobic alumina is prepared by the following steps: A1. Dry the alumina powder to obtain dried alumina powder; A2. Dissolve isopropyl triisostearate titanate in anhydrous ethanol, stir until homogeneous, then add the dried alumina powder obtained in step A1, and ultrasonically disperse at 40-70℃ for 0.5-2h. Once the reaction is complete, hydrophobic alumina is obtained.

6. A tensile composite cable for robots according to claim 5, characterized in that, The ratio of alumina powder, isopropyl triisostearate titanate, and anhydrous ethanol is 10g:0.3-0.5g:100mL.

7. A tensile composite cable for robots according to claim 1, characterized in that, The tensile reinforcement layer is made of ultra-high molecular weight polyethylene fiber.

8. A tensile composite cable for robots according to claim 1, characterized in that, The electromagnetic shielding layer is made of silver-plated copper wire mesh.

9. A method for preparing a tensile composite cable for a robot according to any one of claims 1-8, characterized in that, Includes the following steps: Copper wires are twisted together to form a conductive core layer. Polypropylene is then extruded through a twin-screw extruder to coat the conductive core layer, forming an insulating layer. Ultra-high molecular weight polyethylene fibers are woven into a mesh structure using a high-speed braiding machine to cover the insulating layer, forming a tensile reinforcement layer. Silver-plated copper wire is then used to weave a mesh around the tensile reinforcement layer, forming an electromagnetic shielding layer. Finally, the material of the outer sheath layer is extruded through a twin-screw extruder to coat the surface of the electromagnetic shielding layer, resulting in a tensile composite cable for robots.

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