Self-repairing flexible cable and manufacturing method thereof

Abstract

The invention provides a self-repairing flexible cable and a manufacturing method thereof. The cable comprises two insulating wire cores, a belting layer, a filling layer, a shielding layer and a sheath layer, each insulating wire core is D-shaped, two insulating wire cores are arranged to form a circular cable core, the belting layer wraps the outside of the circular cable core, and the filling layer is filled in the circular cable core; the shielding layer wraps the belting layer, and the sheath layer wraps the shielding layer. The material of the sheath layer comprises self-repairing silicone rubber. The invention further provides a manufacturing method of the self-repairing flexible cable. The self-repairing flexible cable is light in weight, the flexibility is enhanced, the self-repairing flexible cable has real-time temperature monitoring and self-repairing functions, the safety and reliability of long-term operation of equipment can be improved, and the self-repairing flexible cable is convenient to pull to a tower for convenient radiation.

Description

Technical Field

[0001] The present invention relates to the technical field of cable manufacturing, and in particular to a self-repairing soft cable and a manufacturing method thereof. Background Art

[0002] Modern communication network construction places higher demands on base station density and antenna coverage. Cost reduction and energy saving are the key. Adopting the DC power supply method of the cables used for RRU equipment in the base station system for high-power long-distance power transmission is an effective way to reduce costs and save energy. The cables used for RRU power supply equipment should ensure that when there is voltage drop loss in long-distance transmission, the 48V DC power supply in the fixed network access point can still maintain a certain working voltage when it is led to the RRU end of the antenna, so as to ensure the normal operation of the RRU equipment and reduce the cost of base station construction.

[0003] As the power of RRU equipment increases and the height of antenna towers increases, the 400V transmission voltage needs to be increased to 600V, and the line loss increases. The existing round cables are insufficient in current carrying capacity, and cables with larger conductor cross-sections need to be used with RRU equipment. As the height increases, the outer diameter needs to be further reduced and the weight needs to be reduced, which does not meet the requirements of cost reduction and energy saving. The supporting RRU connection cables need to be upgraded urgently. At the same time, considering the long-term exposure of the outdoor power supply tower cable, the risk of external damage due to stress and electric shock, the existing RRU equipment cables cannot monitor the cable operation status in real time. In addition, if the cable sheath is damaged during long-term operation, the integrity of the cable is destroyed, affecting the long-term operation reliability. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a self-repairing flexible cable and a manufacturing method thereof. The self-repairing flexible cable is light in weight, has enhanced flexibility, has real-time temperature monitoring and self-repairing functions, can improve the safety and reliability of long-term operation of the equipment, and is convenient for remote tower radiation.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a self-repairing soft cable, which includes a tape layer, a filling layer, a shielding layer, a sheath layer, and two insulating cores; each insulating core is D-type, and the two insulating cores are arranged to form a circular cable core, the filling layer is filled in the circular cable core, and the tape layer wraps the outside of the circular cable core; the shielding layer wraps the outside of the tape layer, and the sheath layer wraps the outside of the shielding layer; wherein the material of the sheath layer includes self-repairing silicone rubber.

[0006] In the above self-repairing flexible cable, the ratio of the width to the height of the insulating core is generally controlled to be 1.9-2.1, so that the cable core formed by the two insulating cores is a perfect circle.

[0007] In the above self-repairing flexible cable, the insulating core includes an optoelectronic unit conductor and an insulating layer, and the insulating layer wraps the outside of the optoelectronic unit conductor.

[0008] In the above self-repairing flexible cable, the photoelectric unit conductor comprises an electrical conductor and an optical unit. The photoelectric unit conductor is a D-type conductor.

[0009] In some specific embodiments, the photoelectric unit conductor may be twisted around the photoelectric unit with the photoelectric unit as the center and the electrical conductors evenly distributed around the photoelectric unit in a (6+12+18) manner.

[0010] In the above self-repairing flexible cable, the cross-sectional area of ​​the photoelectric unit conductor is 0.5mm 2 -35 mm 2 .

[0011] In the above self-repairing flexible cable, the electrical conductor is formed by twisting monofilaments, and the diameter of each monofilament can be greater than 0.18 mm to prevent the monofilament from breaking and piercing the insulation layer, thereby ensuring the flexibility of the cable. Furthermore, the diameter of each monofilament can be 0.18 mm-0.5 mm.

[0012] In the self-repairing soft cable, the elongation at break of each monofilament is greater than or equal to 30%. By using monofilaments with higher elongation at break, the reliability of the cable can be improved under long-term swing, twisting and even impact conditions in outdoor environments.

[0013] In some specific embodiments, the monofilaments are twisted in a (1+6) manner to form an electrical conductor. The form of multiple strands of twisted wire allows the electrical conductor to have good bending properties.

[0014] In the above-mentioned photoconductor unit, the D-type conductor can significantly reduce the outer diameter of the cable. At the same time, the use of single filaments with higher elongation at break and twisting flexibility can greatly improve the reliability of the cable under long-term swaying, torsion and even impact conditions in outdoor environments.

[0015] In some specific embodiments, the monofilaments may include bare copper wires and / or metal-plated alloy wires. Accordingly, the electrical conductor formed by twisting the monofilaments may be bare copper stranded wires and / or metal-plated alloy stranded wires.

[0016] In the above self-repairing flexible cable, the diameter of the electrical conductor may be 0.54 mm-1.5 mm.

[0017] According to the power supply characteristics of the cable in a long-term outdoor environment, the cable has the risk of insulation temperature rising due to the heat generated by the conductor operation and the difficulty in dissipating heat due to external ultraviolet exposure, and further cracking, resulting in a short circuit failure. In this regard, the present invention adds an optical unit to the cable, which can realize real-time monitoring of the cable operating temperature based on the Raman scattering principle and adopts the technology of photoelectric composite cable (DTS) for sensing temperature, so as to facilitate the evaluation of the long-term operation reliability and remaining life of the cable. In some specific embodiments, the optical unit can be a temperature measuring cable, which can specifically include one of a G-layer-twisted fully dry optical transmission unit, a GX-central tube fully dry optical unit, a GT-layer-twisted filled optical unit and a GXT-central tube filled optical unit.

[0018] In the above self-repairing flexible cable, the material of the insulating layer includes PVC (polyvinyl chloride) and the insulating layer can withstand a temperature of 125°C.

[0019] In the above self-repairing flexible cable, the tape layer is formed by CPP tape (modified polypropylene tape) and / or Mylar aluminum foil wrapping.

[0020] In some specific embodiments, the wrapping overlap rate of the tape layer may be 15%-35%, and further may be 25%-35%.

[0021] In some specific embodiments, the thickness of the CPP tape may be 0.08 mm-0.1 mm.

[0022] In some specific embodiments, the thickness of the Mylar aluminum foil may be 0.03 mm-0.065 mm.

[0023] In the above self-repairing flexible cable, the filling layer includes flame retardant filling ropes and / or filling strips. The material of the filling layer may include PP (polypropylene) and / or PE (polyethylene), etc. Specifically, the filling layer may include one or a combination of two or more of the flame retardant PP rope, flame retardant PE rope, PP filling strip, and PE filling strip.

[0024] In the above self-repairing flexible cable, the shielding layer is a copper-clad copper metal braided layer. In some specific embodiments, the copper-clad copper metal braided layer can be formed by braiding copper-clad copper metal braided wires; more specifically, in the braiding process, the diameter of the copper-clad copper metal braided wires can be 0.11 mm, the braiding angle can be controlled to be 45°-60°, and the braiding density can be controlled to be greater than or equal to 80%.

[0025] In the above-mentioned self-repairing soft cable, the material of the sheath layer includes self-repairing silicone rubber. By adopting the method of extruding a self-repairing silicone rubber sheath to form a sheath layer on the outside of the shielding layer, it is prevented that the cable is damaged due to long-term swaying, twisting or even collision in the outdoor environment, resulting in cable failure, so that the cable has a self-repairing function. Specifically, the self-repairing silicone rubber modifies the methyl vinyl silicone rubber molecular chain and constructs a reversible coordination network (metal coordination bond), so that the chemical cross-linking structure destroyed after the sheath material is damaged or failed can be re-cross-linked, and multiple repairs can be achieved to ensure the integrity of the cable sheath, and prevent further damage to the insulation after the sheath is damaged, causing a cable short circuit, and equipment or system failure. In addition to the self-repairing ability, the sheath layer is also resistant to environmental corrosion and UV rays, which can ensure the reliability of the cable under normal working conditions.

[0026] According to a specific embodiment of the present invention, the raw materials of the self-healing silicone rubber may include the following ingredients in parts by weight: 100 parts of methyl vinyl silicone rubber, 0.5-2.5 parts of 2-isocyanatoethyl acrylate, 1-2 parts of a catalyst, 1-4 parts of dopamine-coated graphene DOPA-Graphene, 0.2-1.6 parts of trivalent iron salt, and 5-15 parts of a pH regulator.

[0027] Among the raw materials of the self-healing silicone rubber, the dopamine-coated graphene DOPA-Graphene, methyl vinyl silicone rubber, and 2-isocyanatoethyl acrylate can undergo a synthesis reaction; the trivalent iron salt can provide Fe 3+ ions, promoting the formation of metal coordination bonds (dopamine and Fe 3+ In addition, the graphene in the dopamine-coated graphene can improve the mechanical properties, electrical properties, etc. of the rubber.

[0028] In some specific embodiments, the preparation method of the graphene-coated dopamine can be: dopamine DOPA and graphene are stirred and mixed in a weight ratio of 1:1 to obtain dopamine-coated graphene DOPA-Graphene.

[0029] In the raw materials of the self-healing silicone rubber, the catalyst includes a Grubb catalyst, for example, the second-generation Grubb catalyst G-2.

[0030] In the raw materials of the self-healing silicone rubber, the pH regulator includes triethylamine.

[0031] In the raw materials of the self-healing silicone rubber, the ferric iron salt is generally a soluble ferric iron salt, for example, may include ferric chloride hexahydrate.

[0032] According to a specific embodiment of the present invention, the method for preparing the self-healing silicone rubber comprises:

[0033] Methyl vinyl silicone rubber, a catalyst, 2-isocyanatoethyl acrylate, and dopamine-coated graphene DOPA-Graphene are mixed and reacted to obtain an intermediate product;

[0034] The intermediate product is mixed with a trivalent iron salt and a pH adjuster (the pH adjuster can adjust the pH value of the system to 10), and dried to obtain a self-healing silicone rubber.

[0035] The present invention adopts the above-mentioned convenient and simple process to construct a reversible metal coordination bond in the self-healing silicone rubber at a low cost, which is conducive to industrial production.

[0036] The ratio of each raw material in the above preparation method is determined according to the ratio of each component in the raw material formula of the above self-healing silicone rubber.

[0037] In the above preparation method, the reaction time may be 3 h-5 h, further may be 3 h-4 h, and the reaction temperature may be room temperature.

[0038] According to a specific embodiment of the present invention, the structural dimensions of the tape layer, filling layer, shielding layer and sheath layer of the self-healing silicone rubber can be adjusted according to actual conditions and requirements, and the present invention does not impose any special restrictions on this.

[0039] According to a specific embodiment of the present invention, when the self-healing silicone rubber is stretched at a rate of 500 mm / min and treated at different temperatures (80°C, 100°C, 120°C) for 4 hours, the mechanical properties (tensile strength, elongation) retention rate of the healed sample can reach more than 80%, and it has a high self-healing ability.

[0040] According to a specific embodiment of the present invention, the self-repairing silicone rubber has a high temperature resistance and good flexibility, and the cable made of the self-repairing silicone rubber has higher flexibility. In some specific embodiments, the self-repairing silicone rubber can have a temperature resistance of up to 150°C and a flexibility of 40A to 70A (A is a Shore hardness unit).

[0041] According to a specific embodiment of the present invention, the self-repairing flexible cable can reduce weight by more than 20% compared with existing cables.

[0042] The present invention also provides a method for manufacturing a self-repairing flexible cable, which comprises wire drawing, annealing, conductor twisting, online conductor profiling and insulation extrusion, cabling and online wrapping, metal shielding braiding, extrusion and continuous vulcanization in sequence; wherein, the process of online conductor profiling and insulation extrusion comprises: profiling the photoelectric unit conductor online, then immediately extruding the insulation, cooling, and obtaining an insulated wire core.

[0043] In the above manufacturing method, online conductor profiling and insulation extrusion are the processes of producing the insulation layer. The conventional process of producing the insulation layer is that the conductor profiling and insulation extrusion are carried out separately in two steps, and the shaping is carried out after the online profiling. For the D-type structure insulation core in the present invention, the conventional method of step-by-step conductor profiling and insulation extrusion is used for processing, which not only leads to more processes, but also the shaping after online profiling will be easy to loose due to the softness of the conductor monofilament (such as bare copper wire, etc.), especially when moving between processes. The loosening problem is more obvious. In this regard, the online profiling and insulation extrusion process used in the present invention is a continuous production process and a step. After the online profiling, the insulation is extruded immediately and then cooled; wherein, the insulation extrusion process can play a role in preliminary shaping by coating the insulation layer on the surface of the cable core, and the cooling process can play a role in re-shaping. The present invention can effectively prevent the loosening of the profiling conductor and ensure the appearance of the D-type conductor (including D-type electrical conductor and D-type photoelectric unit conductor) by carrying out continuous production simultaneously with online profiling and insulation. In addition, the conductor is formed online and the insulation is extruded at the same time, which saves energy and improves production efficiency and circulation efficiency.

[0044] According to a specific embodiment of the present invention, the equipment used for online profiling and insulation extrusion can include a pay-off device, a profiling device, an extrusion device, a cooling water tank, a metering device, a traction device and a wire-receiving device connected in sequence. The profiling device is fixed between the pay-off device and the extruder head of the extrusion device. Before insulation extrusion, the conductor is profiling online, and then insulation extrusion is immediately performed. The online profiling and insulation extrusion are combined into a continuous process, which avoids the loose expansion of the secondary upper and lower plate bow conductors, reduces the process flow, and improves production efficiency.

[0045] According to a specific embodiment of the present invention, a constant pressure can be applied to the optoelectronic unit conductor during the online pressing process to maintain the consistency of the pressed conductor; by controlling the constant pressure range to be greater than 0N and 50N, the appearance, height, width, conductor cross-sectional area and 20°C DC resistance of the D-type conductor can be controlled, and the pressing process of conductors with different cross-sections can be solidified.

[0046] In the above manufacturing method, the mold used for the in-line conductor pressing can be an arcuate (approximately D-shaped) extrusion mold, which includes an arcuate mold core and an arcuate mold sleeve. Existing extrusion molds are usually circular extrusion molds (such as Figure 3 As shown in a of FIG. 1 , the insulated wire core of the present invention is a D-shaped structure. If a circular extrusion die is used, problems such as loose insulation layer coating and excessive stretching causing the D-shaped corner insulation layer to become thinner may occur. In this regard, the present invention adopts a bow-shaped extrusion die (such as Figure 3b), can adapt to the shape of the D-type conductor and match the insulation extrusion material flow, so that the insulation layer can tightly cover the photoelectric unit conductor, avoid excessive stretching causing the insulation layer to be too thin, and can be easily peeled off to facilitate construction and avoid shrinkage and copper exposure. In some specific embodiments, the size and shape of the bow-shaped extrusion die (including the size and shape of the bow-shaped mold core and the bow-shaped mold sleeve) can be designed according to the size and shape of the optical single unit conductor and the insulation layer.

[0047] According to a specific embodiment of the present invention, the above manufacturing method may specifically include:

[0048] S1, sequentially performing wire drawing, annealing, and conductor twisting processes to form an electrical conductor; twisting the electrical conductor with an optical unit to form a photoelectric unit conductor;

[0049] S2, performing online conductor profiling and insulation extrusion, profiling the photoelectric unit conductor online, and then immediately extruding the insulation, cooling, and obtaining an insulated wire core;

[0050] S3, cabling and online wrapping to form a tape layer;

[0051] S4, performing metal shielding braiding, and coating the outer surface of the tape layer to form a shielding layer;

[0052] S5. Perform extrusion and continuous vulcanization to form a sheath layer on the outside of the shielding layer; wherein the extruded raw material includes self-healing silicone rubber.

[0053] In the above manufacturing method, in S1, the temperature of the annealing treatment is generally controlled to be 580-600° C. During the annealing treatment at this temperature, the broken lattices inside the monofilament caused by wire drawing can be reassembled and arranged, and the elongation at break of the monofilament after the annealing treatment can reach more than 30%.

[0054] In the above manufacturing method, in S2, a constant pressure may be applied to the photoelectric unit conductor during the molding process, and the constant pressure is 50N or less.

[0055] In the above manufacturing method, S2 may further include irradiating and cross-linking the insulation layer after the insulation is extruded and cooled. The irradiation cross-linking treatment can improve the temperature resistance level of the insulation material and ensure the stability of the continuous vulcanization of the sheath.

[0056] In the above manufacturing method, the process of S3 may include: cabling the insulated wire cores to obtain a cable core, filling the gaps of the cable core with a filling layer material (PP filling rope, filling strip, etc.) to form a filling layer, and wrapping the material of the wrapping tape layer to form a wrapping tape layer.

[0057] In the above manufacturing process, in S3, the pitch diameter ratio of the cabling may be 25-35.

[0058] In the above manufacturing process, in S3, when the material of the tape layer is Mylar aluminum foil, the thickness of the Mylar aluminum foil may be 0.03-0.065 mm.

[0059] In the above manufacturing process, in S3, when the material of the tape layer is CPP tape, the thickness of the CPP tape can be 0.08 mm-0.1 mm.

[0060] In the above manufacturing process, in S3, the wrapping overlap rate may be 15%-35%, and further may be 25%-35%.

[0061] In the above manufacturing process, the process of S4 may include: using copper-clad copper metal braided wire to weave a metal shielding layer. In some specific embodiments, the diameter of the copper-clad copper metal braided wire may be 0.11 mm, the braiding angle may be 45-60°, and the braiding density may be not less than 80%.

[0062] In the above manufacturing method, in S5, the extrusion process can be carried out by using a rubber extruder. In some specific embodiments, in S5, the diameter of the screw of the rubber extruder can be ψ90mm-ψ150mm, and the type of the screw can be double-headed equidistant composite deepening.

[0063] In the manufacturing method, in S5, during the extrusion process, the temperature of each zone of the rubber extruder can be controlled by a mold temperature controller, and the temperature of the screw, the temperature of the body, and the temperature of the die are all no more than 15° C. By performing the above control, it is possible to avoid premature vulcanization of silicone rubber in the screw chamber and die due to excessively high temperatures due to low vulcanization temperature.

[0064] In the above manufacturing method, in S5, the continuous vulcanization process can be carried out in a vulcanization pipeline, that is, the sheath material enters the vulcanization pipeline immediately after being extruded from the die head for continuous vulcanization.

[0065] In the above manufacturing method, during the continuous vulcanization process of S5, the degree of vulcanization can be controlled by controlling the cable outlet speed, the water level in the vulcanization pipeline and the steam pressure to ensure that the cable has high mechanical properties and elongation at break after vulcanization. In some specific embodiments, the cable outlet speed can be controlled to be _3-12m / min, the water level in the vulcanization pipeline can be controlled to be _25%-40%, and the steam pressure in the vulcanization pipeline can be controlled to be _0.8-1.5MPa. The mechanical strength (tensile strength) of the sheath layer obtained by vulcanization is greater than or equal to 8.0MPa, and the elongation at break is greater than or equal to 200%.

[0066] The self-repairing flexible cable provided by the present invention can reduce the weight of the original cable (compared to the existing cables, the weight can be reduced by more than 20%), enhance the flexibility of the cable, add real-time temperature monitoring and self-repairing functions, improve the safety and reliability of long-term operation of the equipment, meet the rated voltage 0.6 / 1kV use requirements, and can be used as a self-repairing flexible cable for equipment.

[0067] The present invention also provides a RUU device (Remote Radio Unit), which includes the self-repairing flexible cable provided by the present invention. When the cable is applied to the RUU device, it can meet the requirements of the RUU device for cable current carrying capacity, light weight, and long-term operation.

[0068] The beneficial effects of the present invention include:

[0069] 1. The self-repairing flexible cable provided by the present invention utilizes the photoelectric composite cable (DTS) technology for temperature sensing, which can monitor the operating temperature of the cable in real time, making it easier to evaluate the long-term operating reliability and remaining life of the cable.

[0070] 2. The chemical cross-linking structure destroyed after the sheath material used in the above-mentioned self-repairing soft cable provided by the present invention is able to be re-cross-linked to achieve multiple repairs, thereby ensuring the integrity of the sheath and preventing further damage to the insulation after the sheath is damaged, causing cable short circuits and equipment or system failures.

[0071] 3. The self-repairing flexible cable provided by the present invention can meet the rated voltage, and can enhance the flexibility of the cable while reducing the weight of the original cable; and the cable has real-time temperature monitoring and self-repairing functions, which can improve the safety and reliability of the long-term operation of the equipment, and facilitate the remote tower radiation. The self-repairing flexible cable can provide power transmission, information transmission and temperature sensing functions for communication equipment, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 It is a schematic structural diagram of the self-repairing flexible cable of the present invention.

[0073] Figure 2 It is a schematic structural diagram of the photoelectric unit conductor of the present invention.

[0074] Figure 3 The following are photos of a conventional extrusion die and an extrusion die of the present invention.

[0075] Figure 4 It is a schematic structural diagram of the equipment used in the conductor online profiling and insulation string extrusion process of the present invention.

[0076] Explanation of symbols

[0077] Optoelectronic unit conductor 1 , insulating layer 2 , taping layer 3 , filling layer 4 , shielding layer 5 , sheath layer 6 , electrical conductor 11 , optical unit 12 .

[0078] A wire-releasing device 10, a molding device 20, an extruding device 30, a cooling water tank 40, a metering device 50, a traction device 60, and a wire-receiving device 70. DETAILED DESCRIPTION

[0079] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0080] Example 1

[0081] This embodiment provides a self-repairing flexible cable, such as Figure 1 As shown, the cable includes an insulating core, a tape layer 3, a filling layer, a shielding layer 5, and a sheath layer 6.

[0082] There are two insulating wire cores, and the two insulating wire cores have the same shape and size. Each insulating wire core includes a photoelectric unit conductor 1 and an insulating layer 2. The photoelectric unit conductor 1 is a D-type conductor and is covered by the insulating layer 2. Accordingly, the outer shape of each insulating wire core is D-shaped, with one straight side and one curved side.

[0083] The straight sides of the two insulating cores are close to each other, and the curved sides are arranged symmetrically with the straight sides as the center. The ratio of the width and height of each insulating core is 2.0±0.1, so that the two insulating cores are arranged in the above manner to form a complete circle, that is, a circular cable core.

[0084] The tape layer 3 wraps around the outside of the circular cable core (that is, the outside of the curved edge of the insulating core). The filling layer 4 is filled in the circular cable core. The shielding layer 5 wraps around the outside of the tape layer 3, and the sheath layer 6 wraps around the outside of the shielding layer 5.

[0085] like Figure 2 As shown, each photoelectric unit conductor 1 includes an electric conductor 11 and a light unit 12. The photoelectric unit conductor 1 is centered on the light unit 12, and the electric conductor 11 is evenly distributed around the light unit 12 in a (6+12+18) manner, and is twisted according to an outermost layer pitch ratio of 12-20 (specifically, 14). The cross-sectional area of ​​the photoelectric unit conductor 1 can be 0.5mm 2 -35mm 2 The photoelectric unit conductor 1 can be a bare copper stranded wire or a metal alloy-plated stranded wire.

[0086] The conductor 11 is a strand with a diameter of 0.54 mm to 1.5 mm. The conductor 11 is composed of a plurality of (more than two) monofilaments arranged and twisted in a (1+6) manner. The monofilament diameter is 0.18 mm to 0.5 mm, and the monofilament breaking elongation is not less than 30%.

[0087] The optical unit 12 can be one of a G-layer stranded full dry optical transmission unit, a GX-central tube full dry optical unit, a GT-layer stranded filling optical unit and a GXT-central tube filling optical unit. The optical unit can use the temperature measurement optical composite cable (DTS) technology based on the Raman scattering material to monitor the cable operating temperature in real time, so as to facilitate the evaluation of the long-term operating reliability and remaining life of the cable.

[0088] The material of the insulating layer 2 is PVC. The PVC material is soft and can withstand a temperature of 125°C.

[0089] The tape layer 3 is formed by wrapping the tape layer material, and the wrapping overlap rate is 15%-35%. The tape layer material can be CPP tape or Mylar aluminum foil. The thickness of the CPP tape is 0.08-0.1mm, and the thickness of the Mylar aluminum foil is 0.03-0.065mm.

[0090] The material of the filling layer 4 can be PP and / or PE, and the form can be a filling rope and / or a filling strip. In this embodiment, the filling layer 4 is a flame retardant PP filling rope.

[0091] The shielding layer 5 is a copper-clad copper metal braided layer, which is formed by braiding copper-clad copper metal braided wires with a diameter of 0.11 mm, with a braiding angle of 45°-60° and a braiding density of not less than 80%.

[0092] The material of the sheath layer 6 is self-healing silicone rubber. The self-healing silicone rubber used in the present invention is a methyl vinyl silicone rubber molecular chain modified self-healing silicone rubber sheath material, and its raw materials include, by weight (PHR): 100PHR methyl vinyl silicone rubber MVQ, 0.5-2.5PHR 2-isocyanatoethyl acrylate ICA, 1-2PHR catalyst (Grubb catalyst, such as the second generation Grubb catalyst G-2), 1-4PHR dopamine-coated graphene DOPA-Graphene, 0.2-1.6PHR ferric chloride hexahydrate, and 5-15PHR triethylamine TEA as a pH regulator.

[0093] Among the above raw materials, dopamine-coated graphene DOPA-Graphene can react with methyl vinyl silicone rubber and 2-isocyanatoethyl acrylate to form a synthetic reaction; ferric chloride can provide Fe 3+Ions form metal coordination bonds. The methyl vinyl silicone rubber molecular chain in the self-healing silicone rubber prepared using the above raw materials has been modified, and at the same time, the silicone rubber contains reversible metal coordination bonds and can construct a reversible coordination network. The above characteristics enable the sheath material to re-crosslink the destroyed chemical cross-linking structure after damage or failure, achieving multiple repairs, ensuring the integrity of the cable sheath, and preventing further damage to the insulation after the sheath is damaged, causing cable short circuits, and equipment or system failures.

[0094] The preparation method of the self-repairing silicone rubber is:

[0095] (1) Graphene is dispersed in deionized water and ultrasonicated for 1 hour to obtain a graphene suspension. Dopamine DOPA is then added in a weight ratio of graphene to dopamine of 1:1, and stirred for 24 hours to obtain dopamine-coated graphene DOPA-Graphene. In the product, dopamine is located on the surface of the graphene.

[0096] (2) weighing the raw material components in proportion, dissolving methyl vinyl silicone rubber MVQ in tetrahydrofuran solvent in a nitrogen atmosphere, stirring after dissolving for 24 hours, then adding the catalyst and 2-isocyanatoethyl acrylate ICA, stirring at room temperature for 4 hours, to obtain a first reaction system;

[0097] (3) dissolving dopamine-coated graphene DOPA-Graphene in a DMF solution, then adding the first reaction system and reacting for 3 hours to obtain a second reaction system;

[0098] (4) dissolving ferric chloride hexahydrate in THF and adding the solution to the second reaction system, and adjusting the pH value of the second reaction system to about 10 using triethylamine TEA as a pH adjuster to obtain a red-black third reaction system;

[0099] (5) The third reaction system was introduced into a Teflon culture dish and dried in an air circulation oven at 60° C. for 12 h to obtain a self-healing silicone rubber.

[0100] This embodiment also provides a method for manufacturing the self-repairing flexible cable, the method comprising:

[0101] 1. Wire drawing: A copper rod is used to produce a single wire through a wire drawing die with a gradually changing aperture in a small wire drawing machine. In some specific implementation schemes, a single wire as small as 0.1 mm in diameter can be produced.

[0102] 2. Annealing: The monofilament is annealed at 580-600°C in an annealing furnace. During the annealing process, the broken crystal lattices in the monofilament caused by wire drawing are reassembled and arranged. The elongation at break of the monofilament after annealing is greater than or equal to 30%.

[0103] 3. Twisting of the photoelectric unit conductor: Arrange the monofilaments with a diameter of 0.18 mm to 0.5 mm obtained in step 2 in a (1+6) manner to form strands with a diameter of 0.54 mm to 1.5 mm, which are electrical conductors;

[0104] With the optical unit as the center line, the conductors are evenly arranged around the optical unit in the manner of (6+12+18), and twisted into a cross-section of 0.5mm according to the outermost pitch ratio of 12-20 (specifically 14). 2 -35mm 2 The bare copper or metal alloy stranded wire is obtained to obtain the photoelectric unit conductor, which is a D-type conductor. The outer diameter, resistance, pitch and other parameters of the photoelectric unit conductor are tested and then flow to the next process.

[0105] 4. Online conductor profiling and insulation extrusion: A profiling device is fixed between the pay-off and the extruder head to perform online profiling on the photoelectric unit conductor, followed by immediate insulation extrusion (an insulating layer covering the outside of the photoelectric unit conductor is formed during this process), and then cooled and formed to obtain an insulated wire core.

[0106] In the process of online profiling, a constant pressure (greater than 0N and less than or equal to 50N) is applied to the photoelectric unit conductor to ensure the consistency of the profiling conductor, while ensuring the appearance, height, width and 20°C DC resistance of the conductor, and solidifying the profiling process of conductors with different cross-sections;

[0107] like Figure 3 As shown in b, the die used in the online pressing process is a bow-shaped extrusion die, which is composed of a bow-shaped die core and a bow-shaped die sleeve;

[0108] Furthermore, after cooling and forming, the formed insulating wire core can be irradiated and cross-linked to improve the temperature resistance level of the insulating layer and ensure the stability of continuous vulcanization.

[0109] 5. Cabling and online wrapping: Two insulated cable cores are cabled with a pitch-diameter ratio of 25-35. PP filling ropes, filling strips and other filling materials are filled in the gaps of the cable cores. At the same time, Mylar aluminum foil or CPP tape is wrapped to form a tape layer. The thickness of the Mylar aluminum foil is 0.03mm-0.065mm, and the thickness of the CPP tape is 0.08-0.1mm. The wrapping overlap rate is 15-35%, and can be further 25%-35%.

[0110] 6. Metal shielding braiding: The shielding layer is formed by braiding copper-clad copper metal braided wire with a diameter of 0.11mm. The shielding layer is covered on the outside of the tape layer. During the braiding process, the braiding angle is controlled at 45°-60° and the braiding density is not less than 80%.

[0111] 7. Modification of silicone rubber sheath material: Self-healing silicone rubber is prepared using methyl vinyl silicone rubber MVQ, 2-isocyanatoethyl acrylate ICA, a catalyst (Grubb catalyst), dopamine-coated graphene DOPA-Graphene, ferric chloride hexahydrate, a pH adjuster and other raw materials, which is the same as the preparation method of the above-mentioned self-healing silicone rubber.

[0112] 8. Extrusion and continuous vulcanization: Self-repairing silicone rubber is used as the raw material of the sheath layer, and a rubber extruder with a screw diameter of ψ90mm to ψ150mm and a double-head equidistant composite deepening screw type is used to produce the sheath layer:

[0113] During the production process, the temperature of each zone is precisely controlled by a mold temperature controller, and the temperature of the screw, the body and the head does not exceed 15°C; the sheath enters the vulcanization pipeline immediately after being extruded from the head, and the vulcanization degree is controlled by controlling the cable outlet speed, the water level in the vulcanization pipeline and the steam pressure. In this embodiment, the cable outlet speed can be controlled to 3-12m / min, the water level in the vulcanization pipeline can be controlled to 25%-40%, and the steam pressure in the vulcanization pipeline can be controlled to 0.8-1.5MPa.

[0114] In the above manufacturing method, the equipment used for the online conductor profiling and insulation extrusion in step 4 is as follows Figure 4 As shown: the equipment includes a pay-off device 10, a pressing device 20, an extrusion device 30, a cooling water tank 40, a metering device 50, a traction device 60, and a take-up device 70 which are connected in sequence.

[0115] The single insulated wire core (insulating layer + photoelectric unit conductor) prepared in this embodiment was tested, and the extraction force of the insulating layer wrapped around the outside of the photoelectric unit conductor was measured to be 20N-80N, which can achieve the effect of the insulating layer tightly covering the photoelectric unit conductor; and it is easy to peel off to avoid shrinkage and copper exposure.

[0116] The mechanical properties of the self-healing silicone rubber used in this embodiment were tested: the self-healing silicone rubber strips were cut into 30mm×15mm×2mm test strips, the strips were cut into two halves with a knife, and then the two halves of the sample were quickly butt-jointed. When the material was stretched at a rate of 500mm / min and treated at different temperatures (80°C, 100°C and 120°C) for 4h, the mechanical properties (tensile strength and elongation) of the healed strips were tested to have a retention rate of no less than 80%.

[0117] In addition, the temperature resistance of the self-repairing silicone rubber is measured to be 150°C, and the softness is 40A-70A. The tensile strength of the sheath layer obtained by vulcanization is greater than or equal to 8.0MPa, and the elongation at break is greater than or equal to 200%.

[0118] 2×6 (D-type insulated wire core quantity 2, each insulated wire core cross-sectional area 6mm2 ), the self-repairing soft cable with an insulation layer thickness of 0.85mm, a sheath layer thickness of 1.8mm, and an outer diameter of 12.2mm is taken as an example, and the performance test of the cable is carried out. The test method is as follows:

[0119] The long-term operating temperature of the conductor is characterized by the heat aging test recorded in GB / T 3512, the minimum operating temperature is characterized by the low-temperature test recorded in GB / T 1682, the withstand voltage test standard is GB / T 3048.8-2007, and the single-wire flame retardant test method is GB / T 18380.12-2008.

[0120] The main properties of the cable obtained by the above production process of the present invention are shown in Table 1.

[0121] Table 1

[0122]

[0123] It can be seen from Table 1 that the self-repairing flexible cable manufactured by the present invention can withstand a high temperature of 105° C., a low temperature of -40° C., and a voltage of 3.5 kV / 5 min for a long time.

[0124] In terms of photoelectric performance, according to the method of GB / T 3956-2008, the conductor DC resistance of the self-repairing flexible cable of the present invention at 20°C meets the requirements of the standard. The temperature measurement accuracy of the self-repairing flexible cable of the present invention can reach 0.5°C.

[0125] In terms of mechanical properties, the minimum bending radius of the above-mentioned self-repairing flexible cable is 3 times the outer diameter of the cable; the flame retardant performance is flame retardant in a single vertical direction; the tensile strength of the cable sheath layer is 10.3MPa and the elongation at break is 330%.

[0126] In terms of weight, the weight of the self-repairing flexible cable is reduced by more than 20% compared with conventional cables in the art.

[0127] The above results indicate that the self-repairing flexible cable provided by the present invention enhances the flexibility of the cable while reducing its weight, and at the same time has both real-time temperature monitoring and self-repairing functions, thereby improving the safety and reliability of the long-term operation of the equipment.

Claims

1. A self-repairing flexible cable, comprising two insulating cores, a tape layer, a filling layer, a shielding layer, and a sheath layer; Each insulating core is D-shaped, and two insulating cores are arranged to form a circular cable core, the filling layer is filled in the circular cable core, and the tape layer wraps the outside of the circular cable core; the shielding layer wraps the outside of the tape layer, and the sheath layer wraps the outside of the shielding layer; in, The material of the sheath layer includes self-repairing silicone rubber.

2. The self-repairing flexible cable according to claim 1, wherein: The ratio of the width to the height of the insulating core is 1.9-2.

1.

3. The self-repairing flexible cable according to claim 1, wherein: The insulated wire core comprises a photoelectric unit conductor and an insulating layer, wherein the insulating layer wraps the outside of the photoelectric unit conductor; Preferably, the material of the insulating layer includes PVC.

4. The self-repairing flexible cable according to claim 3, wherein: The photoelectric unit conductor comprises an electrical conductor and a light unit, and the photoelectric unit conductor is a D-type conductor; Preferably, the photoelectric unit conductor is twisted around the optical unit with the optical unit as the center and the electrical conductors are evenly distributed around the optical unit in a (6+12+18) manner; Preferably, the cross-sectional area of ​​the photoelectric unit conductor is 0.5 mm 2 -35 mm 2 .

5. The self-repairing flexible cable according to claim 4, wherein: The electrical conductor is formed by twisting monofilaments, the diameter of each monofilament is greater than 0.18 mm, and the elongation at break of each monofilament is greater than or equal to 30%; Preferably, the diameter of each monofilament is 0.18 mm-0.5 mm; Preferably, the monofilaments are twisted in a (1+6) manner to form an electrical conductor; Preferably, the diameter of the electrical conductor is 0.54 mm-1.5 mm.

6. The self-repairing flexible cable according to claim 4, wherein: The optical unit includes one of a G-layer-twisted full-dry optical transmission unit, a GX-central tube full-dry optical unit, a GT-layer-twisted filling optical unit and a GXT-central tube filling optical unit.

7. The self-repairing flexible cable according to claim 1, wherein: The wrapping layer is formed by wrapping CPP tape and / or Mylar aluminum foil; preferably, the wrapping overlap rate of the wrapping layer is 15%-35%; And / or, the material of the filling layer includes PP and / or PE.

8. The self-repairing flexible cable according to claim 1, wherein: The shielding layer is a copper-clad copper metal braided layer; Preferably, the copper-clad copper metal braided layer is formed by braiding copper-clad copper metal monofilaments, the diameter of the copper-clad copper metal monofilaments is preferably 0.11 mm, the braiding angle is preferably 45°-60°, and the braiding density is greater than or equal to 80%.

9. The self-repairing flexible cable according to claim 1, wherein: The raw materials of the self-healing silicone rubber include, by weight: 100 parts of methyl vinyl silicone rubber, 0.5-2.5 parts of 2-isocyanatoethyl acrylate, 1-2 parts of a catalyst, 1-4 parts of dopamine-coated graphene, 0.2-1.6 parts of a trivalent iron salt, and 5-15 parts of a pH regulator; Preferably, the catalyst comprises a Grubb catalyst; Preferably, the pH adjuster comprises triethylamine; Preferably, the ferric iron salt comprises ferric chloride hexahydrate.

10. The self-repairing flexible cable according to claim 9, wherein: The preparation method of the self-repairing silicone rubber comprises: Methyl vinyl silicone rubber, a catalyst, 2-isocyanatoethyl acrylate, and dopamine-coated graphene DOPA-Graphene are mixed and reacted to obtain an intermediate product; The intermediate product is mixed with trivalent iron salt and pH regulator, and dried to obtain self-healing silicone rubber.

11. The method for manufacturing a self-repairing flexible cable according to any one of claims 1 to 10, wherein: The manufacturing method includes wire drawing, annealing, conductor twisting, online conductor profiling and insulation extrusion, cabling and online wrapping, metal shielding braiding, extrusion and continuous vulcanization in sequence; The process of online conductor profiling and insulation extrusion comprises: profiling the photoelectric unit conductor online, then immediately extruding the insulation, and cooling to obtain an insulated wire core.

12. The manufacturing method according to claim 11, wherein: The manufacturing method comprises: S1, sequentially performing wire drawing, annealing, and conductor twisting processes to form an electrical conductor; twisting the electrical conductor with an optical unit to form a photoelectric unit conductor; S2, performing online conductor profiling and insulation extrusion, profiling the photoelectric unit conductor online, and then immediately extruding the insulation, cooling, and obtaining an insulated wire core; S3, cabling and online wrapping to form a tape layer; S4, performing metal shielding braiding, and coating the outer surface of the tape layer to form a shielding layer; S5. Perform extrusion and continuous vulcanization to form a sheath layer on the outside of the shielding layer; wherein the extruded raw material includes self-healing silicone rubber.

13. The manufacturing method according to claim 11 or 12, wherein: The process of in-line pressing includes applying a constant pressure to the photoelectric unit conductor, and the constant pressure is preferably less than 50N; And / or, the mold used in the online pressing process is a bow-shaped extrusion mold, and the bow-shaped extrusion mold includes a bow-shaped mold core and a bow-shaped mold sleeve.

14. The manufacturing method according to claim 12, wherein: In S1, the annealing temperature is 580-600°C; and / or, in S1, the electrical conductor and the optical unit are twisted at a pitch ratio of 12-20 to form an optoelectronic unit conductor; and / or, in S3, cabling is performed according to a pitch diameter ratio of 25-35; And / or, during the extrusion process of S5, the temperature of the screw, the temperature of the body, and the temperature of the die are all less than or equal to 15°C.

15. A RUU device, comprising the self-repairing flexible cable according to any one of claims 1 to 10.

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