A dedicated cable for high-torque robots

Abstract

The application discloses a special cable suitable for high-torque robots. The cable comprises a conductor, an insulating layer, a shielding layer and a sheath layer, the insulating layer is located outside the conductor, the shielding layer is located outside the insulating layer, and the sheath layer is located outside the shielding layer. The raw material of the sheath layer comprises the following components: 40-50 parts of linear low-density polyethylene, 30-40 parts of methyl vinyl silicone rubber, 1-2 parts of a crosslinking agent, 15-25 parts of modified silicon dioxide, 0.5-1 part of an antioxidant and 1-2 parts of a lubricant. The anti-torsion, wear resistance and flame resistance of the cable are improved by optimizing the material formula of the sheath layer, so that the cable can adapt to the frequent movement and complex working conditions of high-torque robots.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of cables, and in particular relates to a special cable suitable for high-torque robots. BACKGROUND

[0002] In the field of high-torque robots, cables, as key energy transmission and signal transmission components, have long been subjected to multiple challenges such as mechanical stress, frequent twisting, and high-temperature environment.

[0003] Traditional cable sheath materials usually adopt a single polymer system, such as polyethylene or rubber, which has certain flexibility and insulation performance, but is prone to problems such as stress concentration, surface wear, and fatigue fracture under high-torque working conditions. In the prior art, some improvement schemes add ordinary inorganic fillers (such as unmodified silicon dioxide) to improve mechanical strength, but due to poor interfacial compatibility between the fillers and the matrix material, the fillers are unevenly dispersed, which further aggravates local stress concentration and reduces the anti-twist performance of the material. In addition, traditional flame-retardant technologies mostly use physical blending of flame retardants, such as halogen or phosphorus compounds, which can short-term improve the flame-retardant effect, but are prone to migration and precipitation in long-term use, not only reducing the flame-retardant durability, but also possibly polluting the environment. More seriously, the poor compatibility of these flame retardants with the matrix material further deteriorates the mechanical properties of the cable. For example, the sheath layer of some commercial high-torque cables is prone to cracking in frequent twisting tests, with a tensile strength of less than 15 MPa and an oxygen index of less than 20%, which is difficult to meet the requirements of high strength, high durability, and high safety of industrial robots.

[0004] Therefore, it is urgent to develop a new cable material with excellent mechanical properties, wear resistance, and stable flame-retardant effect to solve the core defects of poor interfacial compatibility, single function, and insufficient durability in the prior art. SUMMARY

[0005] The present application aims to overcome the defects of the prior art and provides a special cable suitable for high-torque robots.

[0006] The object of the present application can be achieved by the following technical solutions:

[0007] A special cable suitable for high-torque robots, comprising a conductor, an insulation layer, a shielding layer, and a sheath layer, the insulation layer being located outside the conductor, the shielding layer being located outside the insulation layer, and the sheath layer being located outside the shielding layer; wherein the raw material of the sheath layer comprises the following components: 40-50 parts by weight of linear low-density polyethylene, 30-40 parts by weight of methyl vinyl silicone rubber, 1-2 parts by weight of a crosslinking agent, 15-25 parts by weight of modified silicon dioxide, 0.5-1 parts by weight of an antioxidant, and 1-2 parts by weight of a lubricant.

[0008] More preferably, the preparation process of the modified silicon dioxide is:

[0009] A1: Amino-functionalized nano-silica was dispersed in tetrahydrofuran, triethylamine was added, and 2-bromoisobutyryl bromide was added dropwise at 0-5°C. After the dropwise addition was completed, the temperature was raised to room temperature, and stirring was performed overnight. Centrifugation, washing, and drying were performed to obtain brominated silica;

[0010] A2: The brominated silica was mixed with methanol, 2-methacryloyloxyethyl phosphorylcholine, ascorbic acid, and tris(2-pyridylmethyl)amine were added, and argon was bubbled for 30-40 min. Subsequently, copper bromide methanol solution was added, and reaction was performed overnight at room temperature in an argon atmosphere. After the reaction was completed, centrifugation, washing, and drying were performed to obtain amphoteric silica;

[0011] A3: The amphoteric silica was added to a sodium azide methanol solution, and reaction was performed overnight at room temperature. Subsequently, the mixture was transferred to methanol, flame retardant monomers and ascorbic acid were added, and argon was bubbled for 30-40 min. Copper sulfate methanol solution was added, and stirring was performed overnight at room temperature. After the reaction was completed, centrifugation, washing, and drying were performed to obtain modified silica.

[0012] More preferably, the raw materials for preparing the brominated silica include the following components: 1-2 parts of amino-functionalized nano-silica, 50-60 parts of tetrahydrofuran, 9-10 parts of triethylamine, and 18-20 parts of 2-bromoisobutyryl bromide.

[0013] In the scheme, nucleophilic substitution reaction (acylation reaction) occurs between the amino group on the surface of the amino-functionalized nano-silica and 2-bromoisobutyryl bromide, so that the bromide initiator group is connected to the surface of the silica through an amide bond to obtain brominated silica;

[0014] Subsequently, the surface-introduced bromide group is used as an initiator, and an argon atmosphere is used to exclude oxygen interference. Through the catalytic system composed of copper bromide, tris(2-pyridylmethyl)amine ligand, and ascorbic acid, atom transfer radical polymerization (ATRP) is initiated to make the 2-methacryloyloxyethyl phosphorylcholine monomer form a polymer chain containing amphoteric ions on the surface. After overnight reaction at room temperature, centrifugation and washing, amphoteric silica is obtained;

[0015] Finally, the residual bromide group not involved in the polymerization is subjected to SN2 substitution reaction with sodium azide in methanol to generate an azido group. Under argon protection, copper sulfate and ascorbic acid are used to catalyze the copper-catalyzed azido-alkyne cycloaddition reaction between the azido group and the alkyne group in the flame retardant monomer. After overnight stirring at room temperature and post-processing, modified silica is finally obtained. The structure is as follows:

[0016]

[0017] More preferably, the preparation raw materials of the amphoteric silicon dioxide include the following components: 1-2 parts of brominated silicon dioxide, 60-70 parts of methanol, 10-12 parts of 2-methacryloyloxyethyl phosphorylcholine, 0.01-0.02 parts of ascorbic acid, 0.02-0.05 parts of tris(2-pyridylmethyl)amine, and 0.001-0.002 parts of copper bromide methanol solution, in terms of weight fraction.

[0018] More preferably, the preparation raw materials of the modified silicon dioxide include the following components: 1-2 parts of amphoteric silicon dioxide, 60-70 parts of sodium azide methanol solution, 40-50 parts of methanol, 0.08-0.09 parts of flame retardant monomer, 0.04-0.05 parts of ascorbic acid, and 0.01-0.02 parts of copper sulfate methanol solution, in terms of weight fraction; wherein the concentration of the sodium azide methanol solution is 6.5wt%; and the concentration of the copper sulfate methanol solution is 1wt%.

[0019] More preferably, the preparation process of the flame retardant monomer is as follows:

[0020] S1: 4-formaldehyde phenylboronic acid, p-aminobenzoic acid and methanol are fully mixed, heated to 60℃ and stirred for 4-5h, then 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is dissolved in methanol, and it is added to the reaction system within 30min, and the reaction is continued at 60℃ for 10-12h. After the reaction is completed, the methanol in the system is removed by rotary evaporation, washed, filtered and dried at 80℃ to obtain intermediate A;

[0021] S2: Intermediate A and potassium carbonate are added to N,N-dimethylformamide, stirred for 30-40min under nitrogen protection, then propargyl bromide is added dropwise, stirred at room temperature for 12h, and after the reaction is completed, the product is obtained after post-treatment.

[0022] In the scheme, the aldehyde group of 4-formaldehyde phenylboronic acid first reacts with the amino group of p-aminobenzoic acid in methanol solvent at 60℃ to form an intermediate containing an imine structure; then 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) attacks the carbon atom with partial positive charge in the imine group through the activity of its phosphorus-hydrogen bond (P-H) in a nucleophilic addition manner to obtain intermediate A. After that, the carboxyl group of intermediate A is deprotonated in N,N-dimethylformamide solvent with potassium carbonate as the base to form a nucleophilic carboxylate anion, which attacks the saturated carbon atom with partial positive charge in the propargyl bromide molecule to replace the bromine ion through a nucleophilic substitution reaction, so that the propargyl group is connected to the carboxyl group through an ester bond to obtain the flame retardant monomer; the specific synthesis process is as follows:

[0023]

[0024] More preferably, the raw materials for preparing the intermediate A include the following components: 15-16 parts of 4-formaldehyde phenylboronic acid, 13-14 parts of p-aminobenzoic acid, 50-60 parts of methanol, 21-22 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0025] More preferably, the raw materials for preparing the flame-retardant monomer include the following components: 20-25 parts of the intermediate A, 16-18 parts of potassium carbonate, 100-120 parts of N,N-dimethylformamide, 13-14 parts of propargyl bromide.

[0026] More preferably, the antioxidant includes antioxidant 1010 and antioxidant 168 at a mass ratio of 1:1.

[0027] More preferably, the lubricant is calcium stearate.

[0028] Advantages of the present application:

[0029] Firstly, in the scheme, the surface of the modified silica is grafted with amphiphilic polymer chains (2-methacryloyloxyethyl phosphorylcholine) through atom transfer radical polymerization (ATRP). Such amphiphilic chains have good polarity adjustment ability, can form stronger interfacial interaction with linear low-density polyethylene (non-polar) and methyl vinyl silicone rubber (weakly polar) in the sheath layer matrix, and reduce the interfacial defects between inorganic particles and organic matrix. The improvement of interfacial compatibility can effectively disperse the local load of the material under mechanical stress such as torsion and stretching, avoid cracks or fractures caused by stress concentration, thereby enhancing the torsional resistance, tensile strength and fatigue resistance of the sheath layer, adapting to the working condition requirements of frequent movement of high-torque robots; at the same time, the introduction of the amphiphilic chains reduces the surface agglomeration force of the nano-silica, making it more easily dispersed uniformly in the matrix. The uniformly distributed modified silica hinders the sliding of the matrix molecular chain and fills the micro-pores, further enhancing the anti-wear ability of the material surface, reducing the relative volume wear, and improving the wear resistance of the sheath layer.

[0030] Secondly, in the scheme, the phosphorus, boron and nitrogen elements in the flame-retardant monomer grafted on the surface of the modified silica synergistically play a flame-retardant role; the phosphorus element decomposes to generate phosphoric acid substances under heat, catalyzing the formation of a dense and expanded carbon layer and capturing active free radicals, the boron element reacts with the carbon layer to form a high-temperature-resistant structure to enhance the density and oxidation resistance of the carbon layer and suppress smoke, and the nitrogen element releases inert gas to dilute oxygen and synergistically promote the expansion of the carbon layer with the phosphorus, and improves the thermal stability of the flame-retardant monomer by stabilizing the structure; the three elements are fixed on the surface of the silica through covalent bonds to avoid migration, and realize functional complementation through uniform dispersion, thereby significantly improving the flame-retardant effect and safety of the sheath layer. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0032] Preparation: disperse nanosilica in 110 parts of tetrahydrofuran, add 2.5 parts of γ-aminopropyltriethoxysilane, under a protective atmosphere, raise the temperature to 75℃, react for 3.5 hours, then wash the product, vacuum dry, to obtain aminosilica.

[0033] Example 1

[0034] A special cable suitable for high-torque robots is provided, which is sequentially provided from the inside to the outside with a copper conductor, an insulating layer made of polyethylene material, a shielding layer made of chlorinated polyethylene rubber material, and a sheath layer; wherein the preparation method of the sheath layer is as follows:

[0035] After 40 parts of linear low-density polyethylene, 30 parts of methyl vinyl silicone rubber, 1 part of crosslinking agent (such as dicumyl peroxide), 15 parts of modified silica, 0.5 parts of antioxidant (antioxidant 1010 and antioxidant 168 mixed in a mass ratio of 1:1) and 1 part of calcium stearate (lubricant) are mixed by internal mixing (mixed at 120℃ and a rotation speed of 30r / min for 20min), sheeting by an open mill, and granulation by a granulator, the shielding layer is coated outside by an extrusion process, and then crosslinking treatment (reaction at 160℃ and 0.5MPa for 20min) is performed to form the final sheath layer;

[0036] The preparation process of the modified silica is as follows:

[0037] A1: disperse 1 part of aminated nanosilica in 50 parts of tetrahydrofuran, add 9 parts of triethylamine, drop 18 parts of 2-bromoisobutyryl bromide at 0℃, after the dropping is completed, raise the temperature to room temperature, stir overnight, centrifuge, wash, and dry to obtain brominated silica;

[0038] A2: mix 1 part of brominated silica with 60 parts of methanol, add 10 parts of 2-methacryloyloxyethyl phosphorylcholine, 0.01 parts of ascorbic acid, 0.02 parts of tris(2-pyridylmethyl)amine, bubble with argon for 30min, then add 0.001 parts of copper bromide methanol solution (concentration of 1wt%), react overnight at room temperature in an argon atmosphere, after the reaction is completed, centrifuge, wash, and dry to obtain amphoteric silica;

[0039] A3: 1 part of amphoteric silicon dioxide is added to 60 parts of sodium azide methanol solution (concentration of 6.5 wt%), and the reaction is carried out at room temperature overnight, then transferred to 40 parts of methanol, 0.08 parts of flame retardant monomer and 0.04 parts of ascorbic acid are added, and argon is bubbled for 30 min, 0.01 parts of copper sulfate methanol solution (concentration of 1 wt%) is added, and stirred at room temperature overnight, after the reaction is completed, centrifugation, washing, drying, to obtain modified silicon dioxide;

[0040] The preparation process of the flame retardant monomer is:

[0041] S1: 15 parts of 4-formaldehyde phenylboronic acid, 13 parts of p-aminobenzoic acid and 30 parts of methanol are fully mixed, heated to 60℃ and stirred for 4h, then 21 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is dissolved in 20 parts of methanol, which is added to the reaction system within 30 min, and the reaction is continued at 60℃ for 10h, after the reaction is completed, the methanol in the system is removed by rotary evaporation, washed, filtered and dried at 80℃ to obtain intermediate A;

[0042] S2: 20 parts of intermediate A and 16 parts of potassium carbonate are added to 100 parts of N,N-dimethylformamide, stirred for 30 min under nitrogen protection, then 13 parts of propargyl bromide is added dropwise, stirred at room temperature for 12h, after the reaction is completed, the post-treatment is carried out to obtain the flame retardant monomer.

[0043] Example two

[0044] A special cable suitable for high-torque robots is provided, which is provided with a copper conductor, an insulating layer made of polyethylene material, a shielding layer made of chlorinated polyethylene rubber material and a sheath layer from inside to outside; wherein the preparation method of the sheath layer is as follows:

[0045] After 50 parts of linear low density polyethylene, 40 parts of methyl vinyl silicone rubber, 2 parts of crosslinking agent (such as dicumyl peroxide), 25 parts of modified silicon dioxide, 1 part of antioxidant (antioxidant 1010 and antioxidant 168 are mixed in a mass ratio of 1:1) and 2 parts of calcium stearate (lubricant) are mixed by internal mixing (mixing at 130℃ and rotating speed of 40r / min for 30 min), sheeting by open mill and granulating by granulator, the shielding layer is coated outside by extrusion process, and then crosslinking treatment (reaction at 180℃ and 0.8MPa for 30 min) is carried out to form the final sheath layer;

[0046] The preparation process of the modified silicon dioxide is as follows:

[0047] A1: 2 parts of aminated nanosilica is dispersed in 60 parts of tetrahydrofuran, 10 parts of triethylamine is added, 20 parts of 2-bromoisobutyryl bromide is added dropwise at 5℃, after the dropwise addition is completed, the temperature is increased to room temperature, and the stirring is carried out overnight, then centrifugation, washing, drying, to obtain brominated silicon dioxide;

[0048] A2: 2 parts of brominated silica dioxide is mixed with 70 parts of methanol, 12 parts of 2-methacryloyloxyethyl phosphorylcholine, 0.02 parts of ascorbic acid, 0.05 parts of tris(2-pyridylmethyl)amine are added, and argon is bubbled for 40 min, then 0.002 parts of copper bromide methanol solution (concentration of 1 wt%) is added, and the reaction is carried out at room temperature overnight in an argon atmosphere, after the reaction is completed, centrifugation, washing, drying, to obtain amphoteric silica dioxide;

[0049] A3: 2 parts of amphoteric silica dioxide is added to 70 parts of sodium azide methanol solution (concentration of 6.5 wt%), and the reaction is carried out at room temperature overnight, then it is transferred to 50 parts of methanol, 0.09 parts of flame retardant monomer and 0.05 parts of ascorbic acid are added, argon is bubbled for 40 min, 0.02 parts of copper sulfate methanol solution (concentration of 1 wt%) is added, and the reaction is carried out at room temperature overnight, after the reaction is completed, centrifugation, washing, drying, to obtain modified silica dioxide;

[0050] The preparation process of the flame retardant monomer is as follows:

[0051] S1: 16 parts of 4-formaldehyde phenylboronic acid, 14 parts of p-aminobenzoic acid and 35 parts of methanol are fully mixed, heated to 60℃ and stirred for 5h, then 22 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is dissolved in 25 parts of methanol, which is added to the reaction system within 30 min, and the reaction is continued at 60℃ for 12h, after the reaction is completed, the methanol in the system is removed by rotary evaporation, washed, filtered and dried at 80℃ to obtain intermediate A;

[0052] S2: 25 parts of intermediate A and 18 parts of potassium carbonate are added to 120 parts of N,N-dimethylformamide, stirred for 40 min under nitrogen protection, then 14 parts of propargyl bromide is added dropwise, and stirred at room temperature for 12h, after the reaction is completed, the post-treatment is carried out to obtain the flame retardant monomer.

[0053] Example three

[0054] A special cable suitable for high-torque robots is provided, which is provided with a copper conductor, an insulating layer made of polyethylene material, a shielding layer made of chlorinated polyethylene rubber material and a sheath layer from inside to outside; wherein the preparation method of the sheath layer is as follows:

[0055] After mixing 45 parts of linear low-density polyethylene, 35 parts of methyl vinyl silicone rubber, 1.5 parts of a crosslinking agent (such as dicumyl peroxide), 20 parts of modified silica, 0.75 parts of an antioxidant (a mixture of antioxidant 1010 and antioxidant 168 at a mass ratio of 1:1), and 1.5 parts of calcium stearate (a lubricant) in a Banbury mixer (mixing at 125°C and a rotation speed of 35 r / min for 25 min), sheeting on a two-roll mill, and granulation in a granulator, the mixture is coated on the outside of the shielding layer through an extrusion process, and then subjected to crosslinking treatment (reaction at 170°C and 0.65 MPa for 25 min) to form a final sheath layer;

[0056] The preparation process of the modified silica is as follows:

[0057] A1: 1.5 parts of aminated nanosilica are dispersed in 55 parts of tetrahydrofuran, 9.5 parts of triethylamine are added, and 19 parts of 2-bromoisobutyryl bromide are added dropwise at 2.5°C. After the dropwise addition is completed, the temperature is raised to room temperature, and stirring is performed overnight. Centrifugation, washing, and drying are performed to obtain brominated silica;

[0058] A2: 1.5 parts of brominated silica are mixed with 65 parts of methanol, 11 parts of 2-methacryloyloxyethyl phosphorylcholine, 0.015 parts of ascorbic acid, and 0.035 parts of tris(2-pyridylmethyl)amine are added, argon is bubbled for 35 min, and then 0.0015 parts of copper bromide methanol solution (concentration of 1 wt%) is added. Reaction is performed overnight at room temperature in an argon atmosphere. After the reaction is completed, centrifugation, washing, and drying are performed to obtain amphoteric silica;

[0059] A3: 1.5 parts of amphoteric silica are added to 65 parts of sodium azide methanol solution (concentration of 6.5 wt%), and reaction is performed overnight at room temperature. Then, the mixture is transferred to 45 parts of methanol, 0.085 parts of a flame retardant monomer and 0.045 parts of ascorbic acid are added, argon is bubbled for 35 min, and 0.015 parts of copper sulfate methanol solution (concentration of 1 wt%) is added. Stirring is performed overnight at room temperature. After the reaction is completed, centrifugation, washing, and drying are performed to obtain modified silica;

[0060] The preparation process of the flame retardant monomer is as follows:

[0061] S1: 15.5 parts of 4-formaldehyde phenylboronic acid, 13.5 parts of p-aminobenzoic acid, and 32.5 parts of methanol are thoroughly mixed, the temperature is raised to 60°C, and stirring is performed for 4.5 h. Then, 21.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is dissolved in 22.5 parts of methanol, and the solution is added to the reaction system within 30 min. The reaction is continued at 60°C for 11 h. After the reaction is completed, the methanol in the system is removed by rotary evaporation, and the mixture is washed, filtered, and dried at 80°C to obtain intermediate A;

[0062] S2: 22.5 parts of intermediate A and 17 parts of potassium carbonate were added into 110 parts of N,N-dimethylformamide, stirred for 35 min under nitrogen protection, then 13.5 parts of propargyl bromide was added dropwise, stirred at room temperature for 12 h, after the reaction was completed, the post-treatment was performed to obtain the flame-retardant monomer.

[0063] In the preparation process of the modified silica, no flame-retardant monomer was added, and the specific process was as follows:

[0064] A special cable suitable for high-torque robots is provided, which is sequentially provided with a copper conductor, an insulating layer made of polyethylene material, a shielding layer made of chlorinated polyethylene rubber material and a sheath layer from inside to outside; wherein the preparation method of the sheath layer is as follows:

[0065] After 45 parts of linear low-density polyethylene, 35 parts of methyl vinyl silicone rubber, 1.5 parts of crosslinking agent (such as dicumyl peroxide), 20 parts of modified silica, 0.75 parts of antioxidant (antioxidant 1010 and antioxidant 168 mixed in a mass ratio of 1:1) and 1.5 parts of calcium stearate (lubricant) are mixed by internal mixing (mixed at 125℃ and a rotation speed of 35r / min for 25 min), sheeted by an open mill, and granulated by a granulator, the shielding layer is coated outside by an extrusion process, and then crosslinked (reacted at 170℃ and 0.65MPa for 25 min) to form the final sheath layer;

[0066] The preparation process of the modified silica is as follows:

[0067] A1: 1.5 parts of aminated nanosilica was dispersed in 55 parts of tetrahydrofuran, 9.5 parts of triethylamine was added, 19 parts of 2-bromoisobutyryl bromide was added dropwise at 2.5℃, after the dropwise addition was completed, the temperature was increased to room temperature, stirred overnight, centrifuged, washed and dried to obtain brominated silica;

[0068] A2: 1.5 parts of brominated silica was mixed with 65 parts of methanol, 11 parts of 2-methacryloyloxyethyl phosphorylcholine, 0.015 parts of ascorbic acid, 0.035 parts of tris(2-pyridylmethyl)amine were added, argon was bubbled for 35 min, then 0.0015 parts of copper bromide methanol solution (concentration of 1wt%) was added, and the reaction was carried out at room temperature overnight in an argon atmosphere, after the reaction was completed, centrifugation, washing and drying were carried out to obtain the modified silica.

[0069] In the preparation process of the modified silica, no flame-retardant monomer was added, and the specific process was as follows:

[0070] A special cable suitable for high-torque robots is provided, which is sequentially provided with a copper conductor, an insulating layer made of polyethylene material, a shielding layer made of chlorinated polyethylene rubber material and a sheath layer from inside to outside; wherein the preparation method of the sheath layer is as follows:

[0071] After mixing (mixing at 125 DEG C and 35 r / min for 25 min), sheeting on an open mill, and granulating, 45 parts of linear low-density polyethylene, 35 parts of methyl vinyl silicone rubber, 1.5 parts of a crosslinking agent (such as dicumyl peroxide), 0.75 parts of an antioxidant (a mixture of antioxidant 1010 and antioxidant 168 at a mass ratio of 1:1), and 1.5 parts of calcium stearate (a lubricant) are coated on the outside of the shielding layer through an extrusion process, and then crosslinked (reaction at 170 DEG C and 0.65 MPa for 25 min) to form the final sheath layer.

[0072] Test experiment:

[0073] (1) The cables of the examples and the comparative examples are subjected to a twist test at room temperature, and the test method refers to TICW / 01-2009 Appendix B, a total of 10,000 twists are performed, and after the test is completed, whether it passes is evaluated, and the evaluation standard is that there is no crack and distortion phenomenon on the surface of the sample;

[0074] (2) The tensile strength of the sheath layer of the cables of the examples and the comparative examples is tested according to the standard GB / T 1040.3-2006;

[0075] (3) The sheath layer of the cables of the examples and the comparative examples is subjected to a high temperature test according to the standard GB / T 2406.3-2022, and the oxygen index is determined;

[0076] (4) The relative volume abrasion amount of the sheath layer of the cables obtained in the examples and the comparative examples is tested according to the standard GB / T 9867-2008, and the data obtained are shown in the following table:

[0077]

[0078] Conclusion: The application provides a special cable suitable for high-torque robots, and the sheath layer is composed of linear low-density polyethylene, methyl vinyl silicone rubber, modified silicon dioxide and other materials, which significantly improves the mechanical properties and flame retardant properties of the cable.

[0079] Through comparison of the experimental data, the cables of examples one to three all exhibit excellent performance in terms of tensile strength, oxygen index, room temperature twist test and relative volume abrasion amount. Specifically, the tensile strength of the examples reaches 21.1-22.5 MPa, the oxygen index is 28.9%-29.8%, the room temperature twist test is passed, and the relative volume abrasion amount is only 0.81-1.05 mm 3 , which is much better than that of the comparative examples. Especially the performance of the second comparative example (without adding modified silicon dioxide) decreases significantly, the tensile strength is only 12.5 MPa, the oxygen index is 19.3%, and the twist test is not passed, and the relative volume abrasion amount is as high as 2.62 mm 3 ., fully proves that the modified silicon dioxide plays a key role in improving the cable resistance to torsion, wear resistance and flame retardancy. In addition, the oxygen index of Comparative Example 1 (without adding flame retardant monomer) is 21.5%, which is significantly lower than that of the examples, further verifying the importance of the flame retardant monomer.

[0080] In summary, the special cable of the present application realizes the demand of high torque robot for high strength, high wear resistance and high flame retardancy of the cable by optimizing the sheath layer material formula and the preparation process of modified silicon dioxide, and has significant technical advantages and practical application value.

[0081] In the description of the specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0082] The above is only an example and description of the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace, as long as it does not deviate from the invention or exceed the scope defined by the present claims, which shall belong to the protection scope of the present application.

Claims

1. A special cable suitable for high-torque robots, characterized in that, It includes a conductor, an insulating layer, a shielding layer, and a sheathing layer, wherein the insulating layer is located outside the conductor, the shielding layer is located outside the insulating layer, and the sheathing layer is located outside the shielding layer; wherein the raw material of the sheathing layer includes the following components: by weight, 40-50 parts linear low-density polyethylene, 30-40 parts methyl vinyl silicone rubber, 1-2 parts crosslinking agent, 15-25 parts modified silica, 0.5-1 parts antioxidant, and 1-2 parts lubricant; The preparation process of modified silica is as follows: A1: Aminated nano-silica was dispersed in tetrahydrofuran, triethylamine was added, and 2-bromoisobutyryl bromide was added dropwise at 0-5℃. After the addition was completed, the temperature was raised to room temperature, stirred overnight, centrifuged, washed, and dried to obtain brominated silica. A2: Mix silica bromide with methanol, add 2-methacryloyloxyethyl phosphorylcholine, ascorbic acid, and tris(2-pyridylmethyl)amine, bubble with argon for 30-40 min, then add copper bromide methanol solution, and react overnight at room temperature under an argon atmosphere. After the reaction is complete, centrifuge, wash, and dry to obtain amphoteric silica. A3: Add amphoteric silica to sodium azide methanol solution and react overnight at room temperature. Then transfer to methanol, add flame retardant monomer and ascorbic acid, bubble with argon for 30-40 min, add copper sulfate methanol solution, stir overnight at room temperature. After the reaction is complete, centrifuge, wash, and dry to obtain modified silica. The preparation process of the flame-retardant monomer is as follows: S1: Mix 4-formaldehyde phenylboronic acid, p-aminobenzoic acid and methanol thoroughly, heat to 60℃ and stir for 4-5 h. Then dissolve 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in methanol and add it to the reaction system within 30 min. Continue to react at 60℃ for 10-12 h. After the reaction is complete, remove methanol from the system by rotary evaporation, wash, filter and dry at 80℃ to obtain intermediate A. S2: Add intermediate A and potassium carbonate to N,N-dimethylformamide, stir for 30-40 min under nitrogen protection, then add propargyl bromide dropwise, stir at room temperature for 12 h, and after the reaction is complete, perform post-treatment to obtain the flame retardant monomer.

2. The special cable for high-torque robots according to claim 1, characterized in that, The raw materials for preparing the brominated silica include the following components: by weight, 1-2 parts of aminated nano silica, 50-60 parts of tetrahydrofuran, 9-10 parts of triethylamine, and 18-20 parts of 2-bromoisobutyryl bromide.

3. A special cable for high-torque robots according to claim 1, characterized in that, The raw materials for preparing the amphoteric silica include the following components: by weight, 1-2 parts of silica bromide, 60-70 parts of methanol, 10-12 parts of 2-methacryloyloxyethyl phosphorylcholine, 0.01-0.02 parts of ascorbic acid, 0.02-0.05 parts of tris(2-pyridylmethyl)amine, and 0.001-0.002 parts of copper bromide methanol solution; wherein the concentration of the copper bromide methanol solution is 1 wt%.

4. A special cable for high-torque robots according to claim 1, characterized in that, The raw materials for preparing the modified silica include the following components: by weight, 1-2 parts amphoteric silica, 60-70 parts sodium azide methanol solution, 40-50 parts methanol, 0.08-0.09 parts flame retardant monomer, 0.04-0.05 parts ascorbic acid, and 0.01-0.02 parts copper sulfate methanol solution; wherein the concentration of the sodium azide methanol solution is 6.5 wt% and the concentration of the copper sulfate methanol solution is 1 wt%.

5. A special cable for high-torque robots according to claim 1, characterized in that, The raw materials for preparing intermediate A include the following components: by weight, 15-16 parts of 4-formaldehyde phenylboronic acid, 13-14 parts of p-aminobenzoic acid, 50-60 parts of methanol, and 21-22 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

6. A special cable for high-torque robots according to claim 1, characterized in that, The raw materials for preparing the flame retardant monomer include the following components: by weight, 20-25 parts intermediate A, 16-18 parts potassium carbonate, 100-120 parts N,N-dimethylformamide, and 13-14 parts propargyl bromide.

7. A special cable for high-torque robots according to claim 1, characterized in that, The antioxidants include antioxidant 1010 and antioxidant 168 in a mass ratio of 1:

1.

8. A special cable for high-torque robots according to claim 1, characterized in that, The lubricant is calcium stearate.

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