Anti-torsion layering control cable

Abstract

The invention provides an anti-torsion layering control cable, and belongs to the technical field of wires and cables. The anti-torsion layered control cable sequentially comprises a wire core, an insulating layer, a shielding layer, an armor layer, a buffer layer and a sheath layer from inside to outside, the buffer layer contains carboxylated nitrile rubber, the sheath layer contains epoxy resin and a dicyandiamide curing agent, the solid-liquid phase change characteristic of dicyandiamide is utilized, the curing agent is dispersed in a solid state in the granulation stage, and the anti-torsion layered control cable is formed. In the extrusion stage, the curing agent is melted to trigger epoxy ring opening, meanwhile, epoxy groups and carboxyl on the surface of the buffer layer are subjected to interfacial esterification, and the torsion layering resistance of the control cable is improved.

Description

Technical Field

[0001] This invention relates to the field of wire and cable technology, and more particularly to a control cable with anti-torsion delamination. Background Technology

[0002] In fields such as industrial automation, rail transportation, robotics, and large machinery, control cables are key components for achieving precise signal transmission and stable control command delivery. They are commonly used in environments with complex dynamic conditions, including frequent reciprocating motion, small-radius bending, and high-frequency torsion. Under these harsh mechanical conditions, due to external torsional stress, the internal structural layers of the cable (such as between the insulation and shielding layers, between the shielding and armor layers, and especially between the armor layer and the outer sheath layer) are prone to relative slippage, interface separation, and even delamination. This delamination not only compromises the integrity of the cable structure, leading to a decrease in mechanical protection performance, but also causes electrical performance degradation, such as increased signal interference, impedance abrupt changes, and even short circuits or open circuits. This seriously threatens the reliability and safety of the entire control system and significantly shortens the cable's service life.

[0003] Currently, to improve the torsional resistance of control cables, the internal conductor structure of the cable is often optimized or flexible filler materials are added. However, there is a lack of systematic design for the overall cable structure. Although the buffer layer can disperse stress, it is not well bonded to the adjacent layers and is prone to debonding to form a new sliding surface. This makes it difficult to effectively dissipate torque, resulting in limited torsional resistance and anti-delamination effects, which is difficult to meet the long-term use requirements of high dynamic and high reliability applications. Summary of the Invention

[0004] The purpose of this invention is to provide a control cable with anti-torsion delamination capability. The control cable improves its anti-torsion delamination capability by introducing a buffer layer and a sheath layer of specific composition and forming interfacial covalent bonds between the buffer layer and the sheath layer.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a control cable with anti-torsion delamination, which includes, from the inside out, a conductor, an insulation layer, a shielding layer, an armor layer, a buffer layer, and a sheath layer; The method for preparing the anti-torsion delamination control cable includes the following steps: The alloy reinforcing wire and pure copper wire are twisted together to obtain the wire core; An insulation layer is wrapped around the outer layer of the conductor, a shielding layer is wrapped around the outer layer of the insulation layer, and an armor layer is wrapped around the outer layer of the shielding layer to obtain a cable core; Carboxylated nitrile rubber, tackifier, reinforcing filler, vulcanization activator, plasticizer, and antioxidant are mixed together. The resulting buffer layer material is then extruded onto the outer layer of the cable core and continuously vulcanized to form a buffer layer on the outer layer of the cable core. Ethylene-vinyl acetate copolymer, epoxy resin, dicyandiamide curing agent, flame retardant, lubricant and antioxidant are premixed, then melt-blended and granulated. The resulting sheath layer material is then extruded a second time on the outer layer of the buffer layer to form a sheath layer, thus obtaining a torsion-resistant delamination control cable. The temperature for melt blending and granulation is 160~170℃, and the time is 1.5~3min; The temperature of the second extrusion is 190~220℃, and the time is 2~5 minutes.

[0006] Preferably, the alloy reinforcing wire comprises a copper-zinc alloy, a copper-magnesium alloy, or a copper-tin alloy, and the tensile strength of the alloy reinforcing wire is ≥350MPa; The ratio of the alloy reinforcing wire to the pure copper wire is 1:6~12.

[0007] Preferably, the buffer layer comprises the following raw materials in parts by weight: 100 parts of carboxylated nitrile rubber, 2-4 parts of tackifier, 40-60 parts of reinforcing filler, 5-8 parts of vulcanization activator, 10-20 parts of plasticizer, and 1.5-2.5 parts of antioxidant.

[0008] Preferably, the carboxyl content of the carboxylated nitrile rubber is 3-7%, and the acrylonitrile content is 28-35%. The thickener is a resorcinol-acetaldehyde condensate; The reinforcing filler includes carbon black N550, carbon black N660 or carbon black N770; The sulfidation activator is zinc oxide and stearic acid; The plasticizer includes dioctyl phthalate or dioctyl adipate; The antioxidants include antioxidant RD, antioxidant 4010NA, or antioxidant 445.

[0009] Preferably, the sheath layer comprises the following raw materials in parts by weight: 100 parts of ethylene-vinyl acetate copolymer, 15-25 parts of epoxy resin, 2-8 parts of dicyandiamide curing agent, 30-50 parts of flame retardant, 1-2 parts of lubricant, and 0.5-1.5 parts of antioxidant.

[0010] Preferably, the vinyl acetate content of the ethylene-vinyl acetate copolymer is 18-28%, and the melt index is 2-10 g / 10 min; The epoxy resin is a bisphenol A type solid epoxy resin; The flame retardant includes one or more of magnesium hydroxide and aluminum hydroxide; The lubricant includes polyethylene wax or zinc stearate; The antioxidants include antioxidant 1010, antioxidant 1076, or antioxidant 168.

[0011] Preferably, the alloy reinforcing wire and the pure copper wire are twisted in opposite directions, and the pitch ratio of the double twist is 8 to 12 times.

[0012] Preferably, the mixing is carried out in an open mill, the front roll temperature of which is 45~55℃, the rear roll temperature is 40~50℃, and the time is 12~18min. The temperature of the first extrusion is 60~90℃, the time is 1~2min, and the pressure is 8~12MPa.

[0013] Preferably, the continuous vulcanization temperature is 150~160℃, the pressure is 1.2~1.6MPa, and the time is 5~15min.

[0014] Preferably, the premixing temperature is 80~95℃ and the time is 5~10min.

[0015] The beneficial effects of this invention are: This invention, based on the existing control cable structure which, from the inside out, includes a conductor, insulation layer, shielding layer, armor layer, and sheath layer, introduces a buffer layer between the armor layer and the sheath layer. The buffer layer is made of carboxylated nitrile rubber, whose surface carboxyl functional groups remain stable after vulcanization. The sheath layer uses an epoxy resin compounded with a latent dicyandiamide curing agent. Utilizing the solid-liquid phase transition properties of dicyandiamide (melting point 207~209℃), the dicyandiamide curing agent is in a solid dispersion during the granulation stage (160~170℃), while during the extrusion stage (190~220℃), the dicyandiamide curing agent melts, triggering epoxy ring-opening. Simultaneously, the epoxy groups undergo in-situ esterification with the carboxyl groups on the buffer layer surface, generating interfacial covalent bonds. The interfacial bonding force is upgraded from van der Waals forces to covalent bonds, achieving an interfacial peel strength of 28.9~32.6 N / cm, which is comparable to that of conventional physical bonding interfaces (6.8 N / cm). The N / cm) is 4.2 to 4.8 times that of the control cable, and no delamination or cracking was observed under the harsh dynamic torsion test of ±360° and 5000 cycles, which improves the anti-torsion delamination performance of the control cable. Detailed Implementation

[0016] This invention provides a control cable with anti-torsion delamination, which includes, from the inside out, a conductor, an insulation layer, a shielding layer, an armor layer, a buffer layer, and a sheath layer; The method for preparing the anti-torsion delamination control cable includes the following steps: The alloy reinforcing wire and pure copper wire are twisted together to obtain the wire core; An insulation layer is wrapped around the outer layer of the conductor, a shielding layer is wrapped around the outer layer of the insulation layer, and an armor layer is wrapped around the outer layer of the shielding layer to obtain a cable core; Carboxylated nitrile rubber, tackifier, reinforcing filler, vulcanization activator, plasticizer, and antioxidant are mixed together. The resulting buffer layer material is then extruded onto the outer layer of the cable core and continuously vulcanized to form a buffer layer on the outer layer of the cable core. Ethylene-vinyl acetate copolymer, epoxy resin, dicyandiamide curing agent, flame retardant, lubricant and antioxidant are premixed, then melt-blended and granulated. The resulting sheath layer material is then extruded a second time on the outer layer of the buffer layer to form a sheath layer, thus obtaining a torsion-resistant delamination control cable. The temperature for melt blending and granulation is 160~170℃, and the time is 1.5~3min; The temperature of the second extrusion is 190~220℃, and the time is 2~5 minutes.

[0017] In this invention, unless otherwise specified, all raw materials required for preparation are commercially available products well known to those skilled in the art.

[0018] In the anti-torsion delamination control cable provided by the present invention, the alloy reinforcing wire preferably includes a copper-zinc alloy, a copper-magnesium alloy, or a copper-tin alloy, and more preferably a copper-zinc alloy; the tensile strength of the alloy reinforcing wire is preferably ≥350MPa.

[0019] In this invention, the ratio of the alloy reinforcing wire to the pure copper wire is preferably 1:6 to 12, and more preferably 1:8 to 10.

[0020] The insulation layer of the anti-torsion delamination control cable provided by the present invention is preferably a cross-linked polyethylene or polyvinyl chloride insulation layer, and more preferably a cross-linked polyethylene insulation layer.

[0021] The shielding layer of the anti-torsion delamination control cable provided by the present invention is preferably a copper wire braided shielding layer, and the braiding density of the shielding layer is preferably 85~90%, more preferably 86~88%.

[0022] The armor layer of the anti-torsion delamination control cable provided by the present invention is preferably a galvanized steel wire braided or wrapped armor layer, and more preferably a galvanized steel wire braided layer; the braiding density of the armor layer is preferably 80~85%, and more preferably 82~84%.

[0023] The buffer layer of the anti-torsion delamination control cable provided by the present invention preferably comprises the following raw materials in parts by weight: 100 parts of carboxylated nitrile rubber, 2-4 parts of tackifier, 40-60 parts of reinforcing filler, 5-8 parts of vulcanization activator, 10-20 parts of plasticizer, and 1.5-2.5 parts of antioxidant.

[0024] In this invention, the carboxyl content of the carboxylated nitrile rubber is preferably 3-7%, more preferably 4-6%, and the acrylonitrile content is preferably 28-35%, more preferably 30-32%.

[0025] In this invention, the tackifier is preferably 2 to 4 parts by weight, more preferably 3 to 4 parts by weight; the tackifier is preferably a resorcinol-acetaldehyde condensate.

[0026] In this invention, the reinforcing filler is preferably 40-60 parts by weight, more preferably 50-60 parts by weight; the reinforcing filler preferably includes carbon black N550, carbon black N660 or carbon black N770, more preferably carbon black N550 or carbon black N660.

[0027] In this invention, the mass fraction of the sulfidation activator is preferably 5 to 8 parts, more preferably 6 to 7 parts; the sulfidation activator is preferably zinc oxide and stearic acid, and the mass ratio of zinc oxide to stearic acid is preferably 1:0.2 to 0.5.

[0028] In this invention, the plasticizer is preferably 10-20 parts by weight, more preferably 15-20 parts by weight; the plasticizer preferably includes dioctyl phthalate or dioctyl adipate, more preferably dioctyl phthalate.

[0029] In this invention, the antioxidant is preferably 1.5 to 2.5 parts by mass, more preferably 2 to 2.5 parts by mass; the antioxidant preferably includes antioxidant RD, antioxidant 4010NA or antioxidant 445, more preferably antioxidant 4010NA.

[0030] The sheath layer of the anti-torsion delamination control cable provided by the present invention preferably comprises the following raw materials in parts by weight: 100 parts of ethylene-vinyl acetate copolymer, 15-25 parts of epoxy resin, 2-8 parts of dicyandiamide curing agent, 30-50 parts of flame retardant, 1-2 parts of lubricant, and 0.5-1.5 parts of antioxidant.

[0031] In this invention, the ethylene-vinyl acetate copolymer is preferably 100 parts by mass; the vinyl acetate content of the ethylene-vinyl acetate copolymer is preferably 18-28%, more preferably 20-25%, and the melt index is preferably 2-10 g / 10 min, more preferably 5-8 g / 10 min.

[0032] In this invention, the epoxy resin is preferably 15-25 parts by weight, more preferably 20-25 parts by weight; the epoxy resin is preferably a bisphenol A type solid epoxy resin.

[0033] In this invention, the curing agent is preferably 2 to 8 parts by weight, more preferably 3 to 6 parts by weight; the curing agent preferably includes dicyandiamide.

[0034] In this invention, the flame retardant is preferably 30-50 parts by weight, more preferably 40-50 parts by weight; the flame retardant preferably includes one or more of magnesium hydroxide and aluminum hydroxide, more preferably magnesium hydroxide.

[0035] In this invention, the lubricant is preferably 1 to 2 parts by weight, more preferably 1.5 to 2 parts by weight; the lubricant preferably includes polyethylene wax or zinc stearate, more preferably polyethylene wax.

[0036] In this invention, the antioxidant is preferably 0.5 to 1.5 parts by weight, more preferably 1 to 1.5 parts by weight; the antioxidant preferably includes antioxidant 1010, antioxidant 1076 or antioxidant 168, more preferably antioxidant 1010.

[0037] In this invention, the method for preparing the anti-torsion delamination control cable preferably includes the following steps: The alloy reinforcing wire and pure copper wire are twisted together to obtain the wire core; An insulation layer is wrapped around the outer layer of the conductor, a shielding layer is wrapped around the outer layer of the insulation layer, and an armor layer is wrapped around the outer layer of the shielding layer to obtain a cable core; Carboxylated nitrile rubber, tackifier, reinforcing filler, vulcanization activator, plasticizer, and antioxidant are mixed together. The resulting buffer layer material is then extruded for the first time and coated onto the outer layer of the cable core. After continuous vulcanization, a buffer layer is formed on the outer layer of the cable core. Ethylene-vinyl acetate copolymer, epoxy resin, curing agent, flame retardant, lubricant and antioxidant are premixed, then melt-blended and granulated. The resulting sheath layer material is then extruded a second time to form a sheath layer on the outer layer of the buffer layer, resulting in a torsion-resistant delamination control cable. The temperature for melt blending and granulation is 160~170℃, and the time is 1.5~3min; The temperature of the second extrusion is 190~220℃, and the time is 2~5 minutes.

[0038] The present invention preferably selects alloy reinforcing wire and pure copper wire, and performs double twisting by surrounding the alloy reinforcing wire with pure copper wire to obtain the wire core.

[0039] In this invention, the alloy reinforcing wire and the pure copper wire are twisted in opposite directions, and the pitch ratio of the double twist is preferably 8 to 12 times, and more preferably 10 times.

[0040] The present invention preferably uses the conductor as the center, covers the conductor with an insulation layer on the outside of the conductor; covers the insulation layer with a shielding layer on the outside of the insulation layer; and covers the shielding layer with an armor layer on the outside of the shielding layer to obtain the cable core.

[0041] The present invention preferably involves mixing carboxylated nitrile rubber, tackifier, reinforcing filler, vulcanization activator, plasticizer and antioxidant in an open mill, extruding the resulting buffer layer material around the cable core to cover the outer layer of the cable core, and then continuously vulcanizing to form a buffer layer on the outer layer of the cable core.

[0042] In this invention, the front roll temperature of the open mill is preferably 45~55℃, more preferably 45~50℃, the rear roll temperature is preferably 40~50℃, more preferably 40~45℃, and the time is preferably 12~18min, more preferably 12~15min.

[0043] In this invention, the temperature of the first extrusion is preferably 60~90℃, more preferably 70~85℃, and specifically preferably controlled as follows: 65~70℃ in zone one, 75~80℃ in zone two, 75~80℃ in zone three, and 85~90℃ at the die head. The total time of the first extrusion is preferably 1~2 min, and the pressure of the first extrusion is preferably 8~12 MPa, more preferably 8~10 MPa.

[0044] In this invention, the temperature of continuous vulcanization is preferably 150~160℃, more preferably 155~160℃, the pressure is preferably 1.2~1.6MPa, more preferably 1.3~1.5MPa, and the time is preferably 5~15min, more preferably 10~15min.

[0045] The present invention preferably premixes ethylene-vinyl acetate copolymer, epoxy resin, curing agent, flame retardant, lubricant and antioxidant, then melt-blends and granulates them, and then extrudes the resulting sheath layer material with the buffer layer as the center to form a sheath layer on the outer layer of the buffer layer, thereby obtaining a control cable with anti-torsion delamination.

[0046] In this invention, the premixing temperature is preferably 80~95℃, more preferably 85~90℃, and the time is preferably 5~10min, more preferably 5~8min.

[0047] In this invention, the temperature of the melt blending granulation is preferably 160~170℃, and more preferably controlled as follows: Zone 1 160~165℃, Zone 2 165~168℃, Zone 3 165~170℃, and the die head 165~170℃. The total time of the melt blending granulation is preferably 1.5~3min.

[0048] In this invention, the temperature of the second extrusion is preferably 190~220℃, and more preferably controlled as follows: 190~195℃ in zone 1, 195~200℃ in zone 2, 200~210℃ in zone 3, and 210~220℃ at the die head. The total time of the second extrusion is preferably 2~4 minutes.

[0049] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0050] The copper-zinc alloys used in Examples 1-3 contain 62% copper, 23% zinc, and 15% nickel. The carboxylated nitrile rubber used has a carboxyl content of 5.2% and an acrylonitrile content of 32%.

[0051] Example 1

[0052] A copper-zinc alloy with a single wire diameter of 0.25 mm and a tensile strength of 420 MPa was selected as the alloy reinforcing wire. One alloy reinforcing wire was twisted with 12 pure copper wires with a pitch ratio of 10 to obtain the wire core. The core is coated with cross-linked polyethylene to form an insulation layer with an extrusion thickness of 1 mm; tinned copper wire is used to braid the shield with a braiding density of 88% and wrapped around the outside of the insulation layer to form a shielding layer; galvanized steel wire with a diameter of 0.3 mm is used to braid the armor with a braiding density of 82% and wrapped around the outside of the shielding layer to form an armor layer, thus obtaining the cable core. 100 parts of carboxylated nitrile rubber, 3.2 parts of resorcinol-acetaldehyde condensate, 50 parts of carbon black N550, 5 parts of zinc oxide, 1.5 parts of stearic acid, 15 parts of dioctyl phthalate, 2 parts of antioxidant RD, 1.8 parts of sulfur, and 1.2 parts of accelerator DM were placed in an open mill. The front roll temperature of the open mill was set to 50℃ and the rear roll temperature to 45℃. The total mixing time was controlled to be 15 minutes. During the mixing process, the mixture was subjected to a thin-pass treatment 4 times. After the mixing was completed, the first extrusion was carried out. The extruder barrel temperature was set to 65℃ in zone 1, 75℃ in zone 2, 80℃ in zone 3, and 85℃ at the die head. The total extrusion time was controlled to be 1.5 minutes. The extruded material was continuously vulcanized at 155℃ and a steam pressure of 1.4MPa for 10 minutes to form a buffer layer on the outer layer of the cable core. 100 parts of ethylene-vinyl acetate copolymer with a vinyl acetate content of 25%, 20 parts of bisphenol A type solid epoxy resin, 4.5 parts of dicyandiamide, 20 parts of aluminum hydroxide, 20 parts of magnesium hydroxide, 1.2 parts of polyethylene wax, 0.8 parts of antioxidant 1010, and 0.6 parts of antioxidant 168 were mixed at 90°C for 8 minutes. The resulting mixture was then fed into a twin-screw extruder, with the temperatures set to 165°C in zone one, 168°C in zone two, and 168°C in zone three. The temperature was set at ℃, the die head temperature at 167℃, and the total extrusion time was controlled at 2.2 minutes. Melt blending and granulation were carried out. After granulation, the mixture was fed into a single screw extruder. The temperature of the first zone of the single screw extruder was set at 190℃, the temperature of the second zone at 200℃, the temperature of the third zone at 210℃, and the die head temperature at 220℃. The second extrusion was carried out at 15MPa, and the total extrusion time was controlled at 2 minutes. A sheath layer was formed on the outer layer of the buffer layer. Finally, the mixture was cooled at 15℃ to obtain a control cable with an outer diameter of 24.8mm.

[0053] Example 2

[0054] The only difference from Example 1 is: The buffer layer comprises the following raw materials in parts by weight: 100 parts carboxylated nitrile rubber, 2.8 parts resorcinol-acetaldehyde condensate, 55 parts carbon black N660, 5 parts zinc oxide, 1.5 parts stearic acid, 15 parts dioctyl phthalate, 1.8 parts antioxidant 4010NA, 1.8 parts sulfur, and 1.2 parts accelerator DM; The sheath layer comprises the following raw materials in parts by weight: 100 parts ethylene-vinyl acetate copolymer, 18 parts bisphenol A type solid epoxy resin, 3.5 parts dicyandiamide, 15 parts aluminum hydroxide, 20 parts magnesium hydroxide, 1.2 parts polyethylene wax, 0.8 parts antioxidant 1010 and 0.6 parts antioxidant 168; With all other conditions remaining unchanged, the control cable is obtained.

[0055] Example 3

[0056] The only difference from Example 1 is: The buffer layer comprises the following raw materials in parts by weight: 100 parts carboxylated nitrile rubber, 3.8 parts resorcinol-acetaldehyde condensate, 45 parts carbon black N770, 5 parts zinc oxide, 1.5 parts stearic acid, 18 parts dioctyl adipate, 2.2 parts antioxidant 445, 1.8 parts sulfur, and 1.2 parts accelerator DM. The sheath layer comprises the following raw materials in parts by weight: 100 parts ethylene-vinyl acetate copolymer, 22 parts bisphenol A type solid epoxy resin, 5 parts dicyandiamide, 15 parts aluminum hydroxide, 20 parts magnesium hydroxide, 1.2 parts polyethylene wax, 0.8 parts antioxidant 1010 and 0.6 parts antioxidant 168; With all other conditions remaining unchanged, the control cable is obtained.

[0057] Comparative Example 1

[0058] The only difference from Example 1 is: Without a buffer layer, the sheath layer is directly wrapped around the outer layer of the cable core; With other conditions remaining unchanged, a control cable is obtained.

[0059] Comparative Example 2

[0060] The only difference from Example 1 is: No sheath layer is provided; With other conditions remaining unchanged, a control cable is obtained.

[0061] Comparative Example 3

[0062] The only difference from Example 1 is: No buffer layer or sheath layer is provided; With other conditions remaining unchanged, a control cable is obtained.

[0063] Comparative Example 4

[0064] The only difference from Example 1 is: When preparing the buffer layer, the carboxylated nitrile rubber was replaced with nitrile rubber; With other conditions remaining unchanged, a control cable is obtained.

[0065] Comparative Example 5

[0066] The only difference from Example 1 is: No epoxy resin is added during the preparation of the sheath layer; With other conditions remaining unchanged, a control cable is obtained.

[0067] Comparative Example 6

[0068] When preparing the sheath layer, after granulation, it is fed into a single screw extruder. The temperature of the single screw extruder is set to 170℃ in zone one, 175℃ in zone two, 175℃ in zone three, and 180℃ at the die head. With other conditions remaining unchanged, a control cable is obtained.

[0069] Performance testing

[0070] The control cables prepared in Examples 1-3 and Comparative Examples 1-6 were measured according to the following methods, and the results are shown in Table 1. 1. Mechanical properties: The tensile strength of the cable sheath layer in the examples and comparative examples was tested according to GB / T 1040.3-2006; 2. Interface peel strength: Refer to GB / T 2792-2014, peeling is carried out at a peeling speed of 50 mm / min and a peeling angle of 90°, and the average peeling force is recorded; 3. Torsional resistance: Twist the control cable clockwise by 480°, then return it to its natural state, then twist it counterclockwise by 480°, and then return it to its natural state again. This constitutes one cycle, and a total of 5000 cycles of testing are conducted. During this period, an 8-hour heating and 16-hour natural cooling thermal cycle test is performed. During the heating period, the conductor should be kept stable at 90°C. The heating and cooling process should be carried out throughout the entire test. After completing the tests specified in the above test procedure, the sample surface should be visually inspected for cracks and twisting. Then, the cable is dissected to determine whether there are any cracks in the internal parts of the cable. Table 1 Performance results of control cables in Examples 1-3 and Comparative Examples 1-6

[0071] As shown in Table 1, the tensile strength of the control cables prepared in Examples 1-3 is 29.8-32.1 MPa, significantly higher than that of Comparative Examples 1-3 (15.2-19.4 MPa). This indicates that the buffer layer and sheath layer of the present invention form an integral reinforcement structure through interfacial chemical bonding, avoiding stress concentration and premature fracture of the sheath layer due to interfacial debonding. Meanwhile, the interfacial peel strength of the control cables prepared in Examples 1-3 is as high as 28.9-32.6 N / cm, while the interfacial peel strength of Comparative Example 1 is only 6.8 N / cm. The N / cm ratio is due to the interfacial esterification reaction between the epoxy resin in the sheath layer and the carboxyl groups on the surface of the carboxylated nitrile rubber in the buffer layer, forming a covalently bonded chemical interface. In contrast, Comparative Example 1 relies solely on the clamping force generated by the cooling and shrinkage of the sheath layer, which is a physical adsorption and cannot resist dynamic torsional stress. Furthermore, after torsion tests at ±480° and 5000 cycles, the control cables prepared in Examples 1-3 showed intact cross-sections without any delamination, while the control cables in Comparative Examples 1 and 2 showed partial breakage, and the control cable in Comparative Example 3 showed large-area breakage. This indicates that the present invention, through the synergistic design of the raw material system of adding carboxylated nitrile rubber to the buffer layer and using epoxy resin compounded with a latent dicyandiamide curing agent in the sheath layer, achieves in-situ generation of chemical bond anchoring points at the interface, upgrading the interfacial bonding force from physical adsorption van der Waals forces to covalent bonds, fundamentally solving the interfacial delamination problem under dynamic torsion conditions.

[0072] In Comparative Example 4, a buffer layer was prepared using non-carboxylated nitrile rubber (0% carboxyl content). The interfacial peel strength plummeted to 8.1 N / cm, and the tensile strength was only 20.3 MPa. After torsion testing, significant delamination occurred at the interface between the buffer layer and the sheath layer. This indicates that carboxyl functional groups in the buffer layer are essential reaction sites for interfacial esterification. Without carboxyl groups, even if the sheath layer contains an epoxy / dicyandiamide system, covalent bonding cannot be formed, and the interfacial bonding remains at the level of physical adsorption. Furthermore, Comparative Example 5 used a pure EVA sheath layer without epoxy resin. In this system, the sheath layer cannot provide epoxy groups, even if… The buffer layer contains carboxyl groups, and the interface cannot undergo esterification reaction. The peel strength is only 6.2 N / cm. After the torsion test, the sheath layer and the buffer layer partially peel off. This further confirms the necessity of epoxy resin as the main body of covalent bond reaction. The EVA matrix alone cannot form a chemical bond with the carboxyl groups. In Comparative Example 6, the granulation temperature of the sheath layer was increased to 175℃, which caused the dicyandiamide to melt prematurely during the granulation stage. The epoxy resin underwent partial pre-crosslinking. After granulation, the material fluidity decreased, the number of active epoxy groups decreased during extrusion, and the degree of reaction with the carboxyl groups of the buffer layer was greatly reduced. The interfacial peel strength was only 6.9 N / cm.

[0073] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A control cable with anti-torsion delamination, characterized in that, From the inside out, it includes the conductor, insulation layer, shielding layer, armor layer, buffer layer, and sheath layer. The method for preparing the anti-torsion delamination control cable includes the following steps: The alloy reinforcing wire and pure copper wire are twisted together to obtain the wire core; An insulation layer is wrapped around the outer layer of the conductor, a shielding layer is wrapped around the outer layer of the insulation layer, and an armor layer is wrapped around the outer layer of the shielding layer to obtain a cable core; Carboxylated nitrile rubber, tackifier, reinforcing filler, vulcanization activator, plasticizer, and antioxidant are mixed together. The resulting buffer layer material is then extruded onto the outer layer of the cable core and continuously vulcanized to form a buffer layer on the outer layer of the cable core. Ethylene-vinyl acetate copolymer, epoxy resin, dicyandiamide curing agent, flame retardant, lubricant and antioxidant are premixed, then melt-blended and granulated. The resulting sheath layer material is then extruded a second time on the outer layer of the buffer layer to form a sheath layer, thus obtaining a torsion-resistant delamination control cable. The temperature for melt blending and granulation is 160~170℃, and the time is 1.5~3min; The temperature of the second extrusion is 190~220℃, and the time is 2~5 minutes.

2. The anti-torsion delamination control cable according to claim 1, characterized in that, The alloy reinforcing wire includes a copper-zinc alloy, a copper-magnesium alloy, or a copper-tin alloy, and the tensile strength of the alloy reinforcing wire is ≥350MPa; The ratio of the alloy reinforcing wire to the pure copper wire is 1:6~12.

3. The anti-torsion delamination control cable according to claim 1, characterized in that, The buffer layer comprises the following raw materials in parts by weight: 100 parts carboxylated nitrile rubber, 2-4 parts tackifier, 40-60 parts reinforcing filler, 5-8 parts vulcanization activator, 10-20 parts plasticizer, and 1.5-2.5 parts antioxidant.

4. The anti-torsion delamination control cable according to claim 3, characterized in that, The carboxylated nitrile butadiene rubber has a carboxyl content of 3-7% and an acrylonitrile content of 28-35%. The thickener is a resorcinol-acetaldehyde condensate; The reinforcing filler includes carbon black N550, carbon black N660 or carbon black N770; The sulfidation activator is zinc oxide and stearic acid; The plasticizer includes dioctyl phthalate or dioctyl adipate; The antioxidants include antioxidant RD, antioxidant 4010NA, or antioxidant 445.

5. The anti-torsion delamination control cable according to claim 1, characterized in that, The sheath layer comprises the following raw materials in parts by weight: 100 parts ethylene-vinyl acetate copolymer, 15-25 parts epoxy resin, 2-8 parts dicyandiamide curing agent, 30-50 parts flame retardant, 1-2 parts lubricant, and 0.5-1.5 parts antioxidant.

6. The anti-torsion delamination control cable according to claim 5, characterized in that, The ethylene-vinyl acetate copolymer has a vinyl acetate content of 18-28% and a melt index of 2-10 g / 10 min; The epoxy resin is a bisphenol A type solid epoxy resin; The flame retardant includes one or more of magnesium hydroxide and aluminum hydroxide; The lubricant includes polyethylene wax or zinc stearate; The antioxidants include antioxidant 1010, antioxidant 1076, or antioxidant 168.

7. The anti-torsion delamination control cable according to claim 1, characterized in that, The alloy reinforcing wire and the pure copper wire are twisted in opposite directions, and the pitch ratio of the double twist is 8~12.

8. The anti-torsion delamination control cable according to claim 1, characterized in that, The mixing is carried out in an open mill, with the front roll temperature of the open mill being 45~55℃ and the rear roll temperature being 40~50℃, for a time of 12~18 minutes. The temperature of the first extrusion is 60~90℃, the time is 1~2min, and the pressure is 8~12MPa.

9. The anti-torsion delamination control cable according to claim 1, characterized in that, The continuous vulcanization process is carried out at a temperature of 150-160°C, a pressure of 1.2-1.6 MPa, and a time of 5-15 minutes.

10. The anti-torsion delamination control cable according to claim 1, characterized in that, The premixing temperature is 80~95℃, and the time is 5~10min.

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