Vehicle-mounted flame-retardant optical cable and preparation method thereof

Abstract

The invention discloses a vehicle-mounted flame-retardant optical cable and a preparation method thereof, and belongs to the technical field of optical communication, the vehicle-mounted flame-retardant optical cable comprises an optical unit and at least one reinforcer, the surface of the reinforcer is coated with a flame-retardant coating, and the flame-retardant coating at least comprises ammonium octamolybdate and a smoke suppressant; and the outer sheath wraps the periphery of the stranded structure of the plurality of reinforcing members and the optical unit. According to the vehicle-mounted flame-retardant optical cable, a compact carbon layer structure is formed through ammonium octamolybdate under high temperature and open fire, the reinforcer is prevented from making contact with external air, fire is prevented from spreading along the reinforcer, and the flame-retardant effect is achieved; meanwhile, the smoke suppressant can restrain the smoke generation amount, looseness of the compact carbon layer structure caused by smoke is avoided, and secondary combustion caused by falling of the compact carbon layer is avoided. According to the vehicle-mounted flame-retardant optical cable provided by the invention, the reinforcer in the optical cable is replaced by the flame-retardant structure, so that the situation that the optical cable is continuously burnt and damaged along the reinforcer is avoided, and the burning of the vehicle-mounted flame-retardant optical cable is slowed down.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical communication, and particularly relates to a vehicle-mounted flame-retardant optical cable and a preparation method thereof. BACKGROUND

[0002] In the past decade, the application of optical fiber cables in non-communication fields has been continuously expanding, and vehicle-mounted wiring harnesses have gradually shifted from traditional cable products to optical cable products with higher transmission capacity. At present, electrical wiring harnesses are still used as the main transmission connection product in vehicle-mounted wiring harnesses. With the gradual improvement of signal requirements for intelligent driving vehicles, the original electrical transmission wiring harnesses cannot meet the actual signal transmission requirements.

[0003] Vehicle-mounted optical cables are different from traditional optical cables. Traditional optical cables are mainly laid in buildings and pipelines, and their use and laying environments are relatively stable. In the vehicle-mounted environment, the vehicle-mounted optical cable moves with the vehicle, and the vehicle-mounted environment is relatively uncontrollable, and various special environmental conditions, such as high-cold and high-temperature environments, are often encountered. Secondly, compared with indoor environments, vehicle-mounted optical cables have higher requirements for communication stability. In order to avoid the disconnection of vehicle communication at the first time when the vehicle encounters a fire or an accident, the optical cable itself needs to have certain fireproof and flame-retardant capabilities to facilitate traffic accident rescue. However, the existing optical cables cannot meet the special requirements of vehicle-mounted environments, and they are easy to melt and drip under high-temperature open flames, causing secondary ignition. Moreover, the heat conduction effect of conventional reinforcing members is good, which can accelerate the spread of fire and cause the vehicle fire to be uncontrollable. SUMMARY

[0004] In view of one or more of the above defects or improvement needs of the prior art, the application provides a vehicle-mounted flame-retardant optical cable to solve the problem that the existing optical cable is easy to cause fire spread when applied to a vehicle-mounted environment.

[0005] To achieve the above-mentioned purpose, the application provides a vehicle-mounted flame-retardant optical cable, which comprises: an optical unit; at least one reinforcing member, the surface of the reinforcing member being coated with a flame-retardant coating, the flame-retardant coating comprising at least ammonium octamolybdate and a smoke suppressant; an outer sheath wrapped around the outer periphery of the twisted structure of the plurality of reinforcing members and the optical unit.

[0006] As a further improvement of the application, the reinforcing member is a plurality of reinforcing members, and the plurality of reinforcing members are twisted and coated around the outer periphery of the optical unit.

[0007] As a further improvement of the application, the smoke suppressant is one or more of basic copper carbonate, magnesium hydroxide, and aluminum hydroxide.

[0008] As a further improvement of the application, the reinforcing member is a phosphated steel wire, and the surface roughness Ra of the phosphated steel wire is 1.6-3.2 microns. Or, the reinforcing member is an FRP rod, and a surface roughness Ra of the FRP rod is 3.2-6.3 μm.

[0009] As a further improvement of the application, the reinforcing member is a phosphorized steel wire, and a surface of the phosphorized steel wire is coated with a silane coupling agent. Or, the reinforcing member is an FRP rod, and a surface of the FRP rod is coated with 0.05-0.1 mm of a flame-retardant epoxy resin.

[0010] As a further improvement of the application, the flame-retardant coating is formed on the surface of the reinforcing member by a flame-retardant solution, and the flame-retardant solution comprises, by weight component, 2%-8% of ammonium octamolybdate, 3%-5% of basic copper carbonate, and the balance of ammonia water.

[0011] As a further improvement of the application, the outer sheath is a ceramic sheath, and the ceramic sheath forms a ceramic skeleton structure at 500°C.

[0012] As a further improvement of the application, the ceramic sheath comprises, by component, base silicone rubber, zirconium silicate, magnesium hydroxide, red phosphorus master batch, and peroxide DCP.

[0013] The application further comprises a preparation method of the vehicle-mounted flame-retardant optical cable. S1, selecting a reinforcing member and performing surface treatment on the reinforcing member; S2, coating a flame-retardant coating on an outer periphery of the reinforcing member; S3, pulling an optical unit and twisting the reinforcing member in an axial direction of the optical unit; S4, extruding an outer sheath on an outer periphery of a twisted structure of the reinforcing member and the optical unit to obtain the vehicle-mounted flame-retardant optical cable.

[0014] As a further improvement of the application, step S2 comprises: selecting ammonium octamolybdate, basic copper carbonate and ammonia water according to a set ratio, and adding the ammonium octamolybdate, the basic copper carbonate and the ammonia water into a stirring device to stir and mix, so as to obtain a flame-retardant solution; adding the flame-retardant solution into an immersion tank, pulling the reinforcing member through the immersion tank, and immersing the reinforcing member in the immersion tank for 10-15 s; and blowing the surface of the reinforcing member by using a hot air gun to remove excess flame-retardant solution on the surface of the reinforcing member; sending the reinforcing member coated with the flame-retardant solution into a first heating cavity, heating at a temperature of 50-80°C for 1-3 h; sending the reinforcing member passing through the first heating cavity into a second heating cavity, heating at a temperature of 80-100°C for 1-3 h; naturally cooling the reinforcing member to room temperature to obtain the reinforcing member with the flame-retardant coating.

[0015] As a further improvement of the present application, step S4 comprises: The magnesium hydroxide and zirconium silicate are dried in an oven at 80-100 DEG C for 2-3 hours to remove the moisture in the magnesium hydroxide and zirconium silicate; the base silicone rubber is plasticized by a banbury mixer at a temperature of 60-80 DEG C for 3-5 minutes; the zirconium silicate and magnesium hydroxide are added into the banbury mixer in sequence and mixed for 5-8 minutes until the zirconium silicate and magnesium hydroxide are uniformly dispersed in the base silicone rubber; the red phosphorus master batch and peroxide DCP are added into the banbury mixer and mixed for 4-6 minutes to obtain a rubber mixing compound; the rubber mixing compound is pressed into a sheet and cut to obtain a ceramic sheath material; The ceramic sheath material is added into an extruder, the traction reinforcing member and the light unit twisted structure pass through an extrusion die, and the ceramic sheath is formed on the outer periphery of the traction reinforcing member and the light unit twisted structure; The formed ceramic sheath passes through a first section of a curing tank at a curing temperature of 160-180 DEG C to obtain a ceramic sheath with a set shape; The ceramic sheath passes through a drying device at a temperature of 200-220 DEG C to obtain a vehicle-mounted flame-retardant optical cable.

[0016] The present application also includes a vehicle-mounted flame-retardant optical cable, which comprises: a light unit; an outer sheath arranged on the outer periphery of the light unit, at least two reinforcing members being embedded in the outer sheath and symmetrically arranged in the outer sheath; the surface of the reinforcing member is coated with a flame-retardant coating, the flame-retardant coating comprising at least ammonium octamolybdate and a smoke suppressant.

[0017] The present application also includes a vehicle-mounted flame-retardant optical cable, which comprises: a reinforcing member, the surface of the reinforcing member being coated with a flame-retardant coating, the flame-retardant coating comprising at least ammonium octamolybdate and a smoke suppressant; a plurality of light units, the plurality of light units being twistedly arranged on the outer periphery of the reinforcing member; an outer sheath wrapped on the outer periphery of the twisted structure of the plurality of light units and the reinforcing member.

[0018] The above technical features can be combined with each other as long as they do not conflict with each other.

[0019] Overall, the above technical solutions conceived by the present application have the following beneficial effects compared with the prior art: (1) The vehicle-mounted flame-retardant optical cable of the present application, by coating the surface of the reinforcing member in the optical cable with a flame-retardant coating, the ammonium octamolybdate in the flame-retardant coating combines with the reinforcing member to form a dense carbon layer structure under high temperature and open flame conditions, the dense carbon layer structure avoids the internal reinforcing member from contacting air to prevent the continuous combustion of the reinforcing member, avoids the transmission of fire along the reinforcing member, and achieves the effect of flame retardation; at the same time, the smoke suppressant in the flame-retardant coating can suppress the generation of smoke, avoid the loosening of the dense carbon layer structure caused by smoke, avoid the secondary combustion caused by the shedding of the dense carbon layer, and ensure the flame-retardant effect of the flame-retardant coating. The vehicle-mounted flame-retardant optical cable in the present application replaces the reinforcing member in the optical cable with a flame-retardant reinforcing member, forms a flame-retardant structure around the optical unit through the reinforcing member, reduces the probability of the internal optical fiber being burned out, and can avoid the transmission of heat along the reinforcing member under high temperature or open flame environment, causing the burning and damage of the optical cable along the line.

[0020] (2) The vehicle-mounted flame-retardant optical cable of the present application, by the synergistic effect of ammonium octamolybdate and basic copper carbonate, both of which produce molybdenum trioxide and copper oxide under high temperature, both of which are Lewis acids, and form a double catalytic system, which can synergistically increase the carbonization rate of the reinforcing member, increase the density of the carbon layer, and inhibit combustion; at the same time, ammonium octamolybdate and basic copper carbonate are progressive combustion decomposition, which can continuously generate carbon layer structure during the combustion stage to ensure the flame-retardant effect of the carbon layer.

[0021] (3) The vehicle-mounted flame-retardant optical cable of the present application selects a reinforcing member with flame-retardant effect, uses low-smoke halogen-free flame-retardant polyolefin to prepare the loose tube, and uses ceramic sheath as the outer sheath to form an optical cable with internal and external flame-retardant structure, thereby greatly improving the flame-retardant performance of the vehicle-mounted flame-retardant optical cable and avoiding the problem of instantaneous failure of the internal network of the vehicle under high temperature or combustion environment. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic diagram of the overall structure of one of the vehicle-mounted flame-retardant optical cables in the embodiments of the present application; Figure 2 is a flowchart of the preparation method of the vehicle-mounted flame-retardant optical cable in the embodiments of the present application; Figure 3 is a schematic diagram of the overall structure of another vehicle-mounted flame-retardant optical cable in the embodiments of the present application; Figure 4 is a schematic diagram of the overall structure of another vehicle-mounted flame-retardant optical cable in the embodiments of the present application.

[0023] In all the drawings, the same reference signs represent the same technical features, specifically: 1, reinforcing member; 2, flame-retardant coating; 3, optical fiber unit; 4, loose tube; 5, outer sheath. DETAILED DESCRIPTION

[0024] In order to make the objects, technical solutions and advantages of the present application clearer, the following further describes the present application with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present application and not to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0025] In the description of the present application, it should be understood that, unless otherwise specified, the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is merely for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0026] In addition, unless otherwise specified, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0027] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0028] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0029] Embodiment 1: Please refer to Figure 1 、 Figure 2 The vehicle-mounted flame-retardant optical cable in the application comprises an optical unit, at least one reinforcing member 1, a flame-retardant coating 2 coated on the surface of the reinforcing member 1, and the flame-retardant coating 2 comprising at least ammonium octamolybdate and a smoke suppressant, and an outer sheath 5 wrapped around the outer periphery of the twisted structure of the plurality of reinforcing members 1 and the optical unit.

[0030] The vehicle-mounted flame-retardant optical cable in the application, by coating the flame-retardant coating 2 on the surface of the reinforcing member 1 in the optical cable, the ammonium octamolybdate in the flame-retardant coating 2 combines with the reinforcing member 1 to form a dense carbon layer structure under high temperature and open flame conditions, the dense carbon layer structure avoids the internal reinforcing member 1 from contacting air, so as to prevent the continuous combustion of the reinforcing member 1 and the spread of fire along the reinforcing member 1, thereby achieving the flame-retardant effect; at the same time, the smoke suppressant in the flame-retardant coating 2 can suppress the generation of smoke, avoid the loosening of the dense carbon layer structure caused by the smoke, avoid the secondary combustion caused by the shedding of the dense carbon layer, and ensure the flame-retardant effect of the flame-retardant coating 2. The vehicle-mounted flame-retardant optical cable in the application, by replacing the reinforcing member 1 in the optical cable with the flame-retardant reinforcing member 1, forms a ring-shaped flame-retardant structure around the optical unit through the reinforcing member 1, so as to protect the optical unit inside, reduce the probability of the internal optical fiber being burned out, and improve the flame-retardant performance of the optical cable.

[0031] Specifically, when encountering open flame and high temperature, the ammonium octamolybdate in the flame-retardant coating 2 decomposes to release ammonia and generate molybdenum trioxide, the molybdenum trioxide as a strong Lewis acid can catalyze the dehydrogenation and cyclization reaction of the reinforcing member 1 substrate, inhibit the pyrolysis of the reinforcing member 1 to generate combustible small molecules (alkanes, alkenes), and promote the formation of a dense and high-temperature-resistant carbon layer structure; the carbon layer structure can physically block the transfer of heat to the inside of the reinforcing member 1, inhibit the contact of oxygen with the substrate, and thus achieve flame retardation. In addition, the ammonia and molybdenum trioxide small molecules released by the decomposition of ammonium octamolybdate can enter the gas phase combustion zone, the ammonia can dilute the concentration of combustible substances and oxygen to reduce the combustion rate; the molybdenum trioxide small molecules can capture hydroxyl radicals, superoxide anions, etc., to terminate the combustion chain reaction cycle, so as to achieve the purpose of inhibiting fire.

[0032] Further, as an optional embodiment of the present application, the plurality of reinforcing members 1 are twisted and covered outside the optical unit; and the reinforcing member 1 has a space ratio of more than 60%, and the minimum distance from the optical unit to the outer sheath 5 is not less than 10% of the diameter of the flame-retardant optical cable. When the space ratio of the reinforcing member 1 in the flame-retardant optical cable is more than 60%, the main part of the flame-retardant optical cable is the reinforcing member 1, and the reinforcing member 1 with the flame-retardant coating 2 can form a physical flame-retardant structure at high temperature to inhibit the sustained combustion of the flame-retardant optical cable and effectively protect the internal optical fiber unit 3. In addition, the present application limits the minimum distance from the optical unit to the outer sheath 5 to slow down the transmission of external high temperature to the internal optical fiber unit 3, slow down the signal attenuation problem caused by high temperature, and avoid the problem of direct interruption of automobile internal communication when a fire occurs.

[0033] Further, as an optional embodiment of the present application, the smoke suppressant in the present application is one or more of basic copper carbonate, magnesium hydroxide, and aluminum hydroxide.

[0034] Optionally, when the smoke suppressant is basic copper carbonate, heating (200-300°C) of the basic copper carbonate releases carbon dioxide and water, and produces copper oxide. Copper oxide itself is a catalyst that can accelerate the breaking and rearrangement of the molecular chain of the reinforcing member 1 to generate a dense carbon layer structure rich in aromatic rings, facilitating the rapid formation of the dense carbon layer; at the same time, copper oxide itself has a high melting point (1326°C), which can be filled in the pores of the dense carbon layer to reduce the cracking of the carbon layer, further improve the heat and oxygen insulation performance of the dense carbon layer, and avoid secondary combustion caused by the falling of the carbon layer; in addition, the carbon dioxide and water produced by basic copper carbonate are both non-combustible components, which can form a non-combustible area on the surface of the reinforcing member 1, on the one hand to reduce the concentration of combustible components around the reinforcing member 1, and on the other hand to reduce the combustion temperature and inhibit the spread of flames and high temperature along the reinforcing member 1. Further, the molybdenum trioxide produced by ammonium octamolybdate and the copper oxide produced by basic copper carbonate are both Lewis acids, and the two form a dual-catalyst system to synergistically increase the carbonization rate of the reinforcing member 1, increase the density of the carbon layer, and inhibit combustion; and ammonium octamolybdate (decomposition temperature 250°C) and basic copper carbonate (decomposition temperature 280°C) are progressive combustion decomposition, which can continuously generate carbon layer structure during the combustion stage to ensure the flame-retardant effect of the carbon layer.

[0035] Optionally, when the smoke suppressant is magnesium hydroxide or aluminum hydroxide, the magnesium hydroxide is heated and decomposed at 340-490°C to produce water and magnesium oxide, the produced water can reduce the temperature around the reinforcing member 1 to achieve the fire-retardant effect, and the magnesium oxide can accumulate on the surface of the reinforcing member 1 to form an inorganic barrier structure to achieve the fire-retardant effect; the aluminum hydroxide is similar to the magnesium hydroxide, which is heated and decomposed at 200-300°C to produce water and aluminum oxide, the mechanism and effect of the aluminum oxide and the magnesium oxide are similar, and the difference between the two is that the magnesium oxide has a higher melting point and is more resistant to high temperature, and the fire-retardant mechanism of the aluminum oxide is not described herein.

[0036] Further, as an optional embodiment of the present application, the reinforcing member 1 in the present application is a phosphated steel wire, and the surface roughness Ra of the phosphated steel wire is 1.6-3.2 μm. When the phosphated steel wire is used as the reinforcing member 1, the surface of the phosphated steel wire needs to be treated to improve the adhesion of the fire-retardant coating 2 to the surface of the reinforcing member 1. Specifically, the surface of the phosphated steel wire can be sandblasted (the particle size of the sand is 50-100 μm) to form a uniform micro-pit structure on the surface of the reinforcing member 1, so that the fire-retardant coating 2 is embedded in the micro-pit to increase the bonding area of the reinforcing member 1 and the fire-retardant coating 2 and improve the adhesion of the fire-retardant coating 2. When the surface roughness of the phosphated steel wire is too high (Ra>3.2 μm), stress concentration may occur at the weak part to reduce the tensile strength of the reinforcing member 1. It is worth noting that the phosphated steel wire itself is not flammable, and the phosphated steel wire cannot form a dense carbon layer structure with ammonium octamolybdate. The phosphated steel wire mainly uses the non-flammable substances and water produced by ammonium octamolybdate and the smoke suppressant to suppress combustion and reduce the temperature of the reinforcing member 1 to avoid the transmission of high temperature along the reinforcing member 1.

[0037] Optionally, when the fire-retardant coating 2 is coated on the surface of the reinforcing member 1, a silane coupling agent can be sprayed on the surface of the reinforcing member 1 to form a chemical bonding layer on the surface of the phosphated steel wire to improve the adhesion of the phosphated steel wire and the fire-retardant coating 2.

[0038] Further, as an optional embodiment of the present application, the reinforcing member 1 in the present application is an FRP rod, and the surface roughness Ra of the FRP rod is 3.2-6.3 μm. When the FRP rod is used as the reinforcing member 1, the FRP rod can be polished by sandpaper to form a porous structure on the surface of the FRP rod to increase the interfacial bonding force of the fire-retardant coating 2 and the reinforcing member 1. Similarly, when the surface roughness of the FRP rod is too high (Ra>6.3 μm), the surface fibers of the FRP rod will be exposed to the outside, causing the local embrittlement of the reinforcing member 1 and affecting the minimum bending radius of the reinforcing member 1, which is not suitable for the complex bending environment of the vehicle-mounted optical cable.

[0039] Optionally, when the reinforcing member 1 in the present application is a phosphated steel wire, the diameter thereof is 0.2 mm-4 mm; and when the reinforcing member 1 is an FRP rod, the diameter thereof is 0.4 mm-4 mm.

[0040] Optionally, when the reinforcing member 1 is coated with the fire-retardant coating 2, the reinforcing member 1 can be treated with a sodium hydroxide solution having a concentration of 5% to 10% to etch the surface of the reinforcing member 1 for 10 to 15 minutes to remove the mold release agent on the surface of the reinforcing member 1 and to increase the number of hydroxyl groups, thereby improving the adhesion between the FRP rod and the fire-retardant coating 2.

[0041] Optionally, when the reinforcing member 1 is coated with the fire-retardant coating 2, a 0.05 to 0.1 mm thick fire-retardant epoxy resin can be coated on the surface layer of the FRP rod. The fire-retardant epoxy resin can fill the pores on the surface of the FRP rod, and cover part of the surface of the FRP rod with the epoxy resin to avoid the problem of local peeling of the fire-retardant coating due to uneven roughness during coating. Optionally, the fire-retardant epoxy resin refers to an epoxy resin to which an inorganic fire-retardant or an organic fire-retardant is added. The inorganic fire-retardant can be one of aluminum hydroxide, magnesium hydroxide, and antimony trioxide, and the organic fire-retardant can be one of decabromobiphenyl ether, red phosphorus pellets, and phosphate ester.

[0042] Further, as an optional embodiment of the present application, the fire-retardant coating 2 in the present application is formed by coating a fire-retardant solution on the outer periphery of the reinforcing member 1 and then drying. The fire-retardant solution includes 2% to 8% of ammonium octamolybdate, 3% to 5% of basic copper carbonate, and the rest of ammonia water in terms of weight components. Specifically, the fire-retardant coating 2 in the present application is mainly composed of a solution. The reinforcing member 1 is immersed in the solution for a set time and then dried to form the fire-retardant coating 2 on the surface of the reinforcing member 1. The ammonia water can react with the basic copper carbonate to form stable and soluble copper-ammonia complex ions. The ammonium ions in the ammonia water and the molybdate ions in the ammonium octamolybdate form a soluble salt, and the hydroxyl ions in the ammonia water can inhibit the polymerization of the molybdate ions, thereby achieving the dissociation and dissolution of the ammonium octamolybdate. When the fire-retardant solution is formed, the fire-retardant solution is coated on the surface of the reinforcing member, and then heated to evaporate the ammonia water. During the evaporation of the ammonia water, the copper-ammonia complex ions and the molybdate ions dissolved in the ammonia water correspond to the formation of basic copper carbonate, ammonium octamolybdate, and a small amount of copper molybdate, thereby achieving the coating of the ammonium octamolybdate and the basic copper carbonate on the surface of the reinforcing member 1.

[0043] Further, as an optional embodiment of the present application, the fire-retardant coating 2 comprises, by weight component, 2% to 8% of ammonium octamolybdate, 3% to 5% of basic copper carbonate, 40% to 50% of water-based acrylic resin, and 5% to 8% of silica sol. The water-based acrylic resin is in a flowable state at room temperature, facilitating the coating of the fire-retardant coating 2 on the surface of the reinforcing member 1; in addition, the water-based acrylic resin can serve as an adhesive and endow the fire-retardant coating 2 with certain flexibility, avoiding cracking caused by vehicle vibration. The silica sol can form an organic-inorganic interpenetrating network with the acrylic resin, improving the overall hardness and temperature resistance of the fire-retardant coating 2. Optionally, the fire-retardant coating 2 further comprises, by weight component, 0.5% to 1% of silane coupling agent, which can act on the surface of the reinforcing member 1 or also serve as a component of the fire-retardant coating 2 to improve the adhesion to the reinforcing member 1.

[0044] Further, as an optional embodiment of the present application, the optical unit comprises the loose tube 4 and at least one optical fiber unit 3 located in the loose tube 4, and the optical fiber unit 3 is preferably a bend-insensitive optical fiber. Water-blocking powder or water-blocking paste is filled between the optical fiber unit 3 and the loose tube 4.

[0045] Preferably, the loose tube 4 is made of low-smoke zero-halogen flame-retardant polyolefin (LSZH), which has a low smoke density when burned. At the same time, phosphorus-nitrogen flame retardants can be added during the preparation of the loose tube 4 to improve the flame-retardant performance of the loose tube 4.

[0046] Further, as an optional embodiment of the present application, the outer sheath 5 is a ceramic sheath that can form a ceramic framework structure above 500℃. Specifically, the ceramic sheath comprises, by weight, 100 to 110 parts of base silicone rubber, 30 to 40 parts of zirconium silicate, 10 to 15 parts of magnesium hydroxide, 5 to 8 parts of red phosphorus masterbatch, and 2 to 3 parts of peroxide DCP (dicumyl peroxide). The base silicone rubber is the basic material of the sheath, facilitating the molding, bending, and laying of the sheath; the magnesium hydroxide can decompose and absorb heat at high temperatures, achieving a flame-retardant effect; and the zirconium silicate can crosslink with the silicone rubber at high temperatures to form a ceramic framework structure of Si-O-Zr, achieving physical flame retardation at high temperatures.

[0047] Further, the present application further comprises a preparation method of the vehicle-mounted flame-retardant optical cable, comprising the following steps: S1, selecting the reinforcing member 1 and performing surface treatment on the reinforcing member 1; S2, coating the fire-retardant coating 2 on the outer periphery of the reinforcing member 1; S3, pulling the optical unit and twisting the reinforcing member 1 along the axial direction of the optical unit; S4, extruding the outer sheath 5 on the outer periphery of the twisted structure of the reinforcing member 1 and the optical unit, to obtain the vehicle-mounted flame-retardant optical cable.

[0048] Further, as an optional embodiment of the present application, step S1 specifically comprises: The steel wire is selected as the base of the reinforcing member 1, sand blasting is performed on the surface of the steel wire to form uniform micro-pits on the surface of the steel wire, a zinc phosphate process is used to treat the steel wire to form a 2-5 μm phosphating film on the outer surface of the steel wire, and the phosphated steel wire is obtained, and the silane coupling agent is sprayed on the surface of the phosphated steel wire.

[0049] Further, as an optional embodiment of the present application, step S1 specifically comprises: The FRP rod is selected as the base of the reinforcing member 1, sandpaper is used to polish the surface of the FRP rod to form a porous structure on the surface of the FRP rod, a 5%-10% NaOH solution is used to etch the FRP rod for 10-15 min, deionized water is used to rinse the surface of the FRP rod until the pH value is 7, the rinsed FRP rod is placed in a hot air drying oven and dried at 80-110°C for 5-10 min, and the FRP rod is cooled to room temperature, and the 0.05-0.1 mm thick flame-retardant epoxy resin primer is coated on the surface of the FRP rod.

[0050] Further, as an optional embodiment of the present application, step S2 specifically comprises: The ammonium octamolybdate, the basic copper carbonate and the ammonia water are selected according to the set ratio, the ammonium octamolybdate, the basic copper carbonate and the ammonia water are added into a stirring device for stirring and mixing until there is no obvious precipitate in the stirring device, and the flame-retardant solution is obtained; The flame-retardant solution is added into an impregnation tank, the reinforcing member 1 is pulled through the impregnation tank, and the reinforcing member 1 is impregnated in the impregnation tank for 10-15 s, and a hot air gun is used to blow the surface of the reinforcing member 1 to remove the excess flame-retardant solution on the surface of the reinforcing member 1; The reinforcing member 1 coated with the flame-retardant solution is sent into a first heating cavity, the heating temperature is 50-80°C, and the heating time is 1-3 h; The reinforcing member 1 passing through the first heating cavity is sent into a second heating cavity, the heating temperature is 80-100°C, and the heating time is 1-3 h; The reinforcing member 1 is naturally cooled to room temperature, and the reinforcing member 1 with the flame-retardant coating 2 is obtained.

[0051] Further, as an optional embodiment of the present application, step S2 specifically comprises: The ammonium octamolybdate, the basic copper carbonate and the ammonia water are selected according to the set ratio, the ammonium octamolybdate, the basic copper carbonate and the ammonia water are added into a stirring device for stirring and mixing until there is no obvious precipitate in the stirring device, and the flame-retardant solution is obtained; The fire-retardant solution is added into the dipping tank, the reinforcing member 1 is pulled through the dipping tank, and the reinforcing member 1 is dipped in the dipping tank for 10-15 s; the surface of the reinforcing member 1 is blown by a hot air gun to evaporate and remove ammonia and moisture in the fire-retardant solution, and the ammonium octamolybdate and basic copper carbonate in the fire-retardant solution are precipitated, so that the reinforcing member 1 with the fire-retardant coating 2 is obtained.

[0052] Further, as an optional embodiment of the present application, step S4 specifically comprises: The magnesium hydroxide and zirconium silicate are dried in an oven at 80-100°C for 2-3 h to remove moisture therefrom and are ready for use; the base silicone rubber is plasticated by using an internal mixer, the plasticating temperature is 60-80°C, and the plasticating time is 3-5 min; the zirconium silicate and the magnesium hydroxide are sequentially added into the internal mixer and are mixed for 5-8 min until the zirconium silicate and the magnesium hydroxide are uniformly dispersed in the base silicone rubber; the red phosphorus master batch and the peroxide DCP are added into the internal mixer and are continuously mixed for 4-6 min to obtain a rubber mixing compound; the rubber mixing compound is tabletted and cut to obtain a ceramic sheath material; The ceramic sheath material is added into an extruder, the reinforcing member 1 and the light unit stranded structure are pulled through an extrusion die, and the ceramic sheath is formed on the outer periphery of the reinforcing member 1 and the light unit stranded structure; The formed ceramic sheath is passed through a first-stage curing tank, and the curing temperature is 160-180°C to obtain a ceramic sheath with a set shape; the first-stage curing process can make the peroxide DCP decompose to generate free radicals, initiate crosslinking of the silicone rubber, and further preliminarily form the ceramic sheath structure; The ceramic sheath is passed through a drying device at 200-220°C to obtain the vehicle-mounted fire-retardant optical cable; the second-stage heating process can remove residual peroxide DCP to improve the aging resistance, fire-retardant property and mechanical property of the outer sheath 5. Preferably, the optical cable prepared by using the preparation method of the vehicle-mounted fire-retardant optical cable is tested according to GB / T31248-2014 “Test methods for fire characteristics of cables or optical cables under defined fire conditions”, GB / T17651.2-1998 “Determination of the smoke density of the burning of cables or optical cables under specified conditions Part 2: Test procedure and requirements” and GB / T 18380.12-2008 “Burning behaviour of cables and optical cables under fire conditions Part 12: Single insulated electrical wires and cables Flame propagation vertical test 1 kW premixed flame test method”, and the measured flame propagation FS is ≤1.5 m, the peak value of the heat release rate HRR peak is ≤30 kW, the total heat release THR within 1200 s of fire is ≤15 MJ, the fire growth rate index FIGRA is ≤150 W / s, the peak value of the smoke production rate SPR peak is ≤0.25 m / s, and the total smoke production TSP within 1200 s of fire is 1200 . 2 .1200 ≤50m 2 ; smoke density (minimum light transmittance) T≥60%; vertical flame spread H≤425mm. The preparation method of the vehicle-mounted flame-retardant optical cable prepared by the present application meets the B1 class combustion performance grade, has good flame-retardant effect, has low smoke density during combustion, is non-toxic, and is suitable for vehicle-mounted environment.

[0053] Example 2: Please refer to Figure 3 The vehicle-mounted flame-retardant optical cable in the present application comprises an optical unit, an outer sheath 5 arranged on the outer periphery of the optical unit, at least two reinforcing members 1 embedded in the outer sheath 5, and the reinforcing members 1 are symmetrically arranged in the outer sheath 5; wherein the surface of the reinforcing member 1 is coated with a flame-retardant coating 2, and the flame-retardant coating 2 at least comprises ammonium octamolybdate and a smoke suppressant.

[0054] The present application also comprises a central tube type optical cable structure, the reinforcing member 1 is embedded in the outer sheath 5, and the optical unit is arranged in the central area of the outer sheath 5. The flame-retardant coating 2 on the outer periphery of the reinforcing member 1 and the outer sheath 5 adopt the same scheme as in Example 1, only another vehicle-mounted flame-retardant optical cable structure is provided here, and the rest will not be repeated.

[0055] Example 3: Please refer to Figure 4 The vehicle-mounted flame-retardant optical cable in the present application comprises a reinforcing member 1, the surface of the reinforcing member 1 is coated with a flame-retardant coating 2, the flame-retardant coating 2 at least comprises ammonium octamolybdate and a smoke suppressant; a plurality of optical units, the plurality of optical units are twistedly arranged on the outer periphery of the reinforcing member 1; and an outer sheath 5, the outer sheath 5 is wrapped on the outer periphery of the twisted structure of the plurality of optical units and the reinforcing member. The materials and processes of the reinforcing member 1, the flame-retardant coating 2 and the outer sheath 5 are the same as in Example 1, only another vehicle-mounted flame-retardant optical cable structure is provided here, and the rest will not be repeated.

[0056] The vehicle-mounted flame-retardant optical cable in the present application replaces the reinforcing member 1 inside the optical cable with a flame-retardant structure, avoiding the heat transfer along the reinforcing member 1 in high temperature or open flame environment, causing the optical cable to burn and damage along the line.

[0057] Those skilled in the art will readily understand that the above description is only a preferred embodiment of the present application and is not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. Vehicle-mounted flame-retardant optical cable, characterized in that: include: Light unit; at least one reinforcement member, wherein a surface of the reinforcement member is coated with a flame retardant coating, wherein the flame retardant coating comprises at least ammonium octamolybdate and a smoke suppressant; An outer sheath is wrapped around the outer periphery of the twisted structure of the plurality of reinforcement members and the optical unit.

2. The vehicle-mounted flame-retardant optical cable according to claim 1, characterized in that: The smoke suppressant is one or more of basic copper carbonate, magnesium hydroxide, and aluminum hydroxide.

3. The vehicle-mounted flame-retardant optical cable according to claim 1, characterized in that: The reinforcement is a phosphated steel wire, and the surface roughness Ra of the phosphated steel wire is 1.6-3.2 μm; Alternatively, the reinforcement is an FRP rod, and the surface roughness Ra of the FRP rod is 3.2-6.3 μm.

4. The vehicle-mounted flame-retardant optical cable according to claim 1, characterized in that: The reinforcement is a phosphated steel wire, and the surface of the phosphated steel wire is coated with a silane coupling agent; Alternatively, the reinforcement is an FRP rod, and the surface of the FRP rod is coated with a flame retardant epoxy resin with a thickness of 0.05 to 0.1 mm.

5. The vehicle-mounted flame-retardant optical cable according to claim 1, characterized in that: The flame retardant coating is formed by coating a flame retardant solution on the surface of the reinforcement. The flame retardant solution comprises, by weight, 2% to 8% of ammonium octamolybdate, 3% to 5% of basic copper carbonate, and the balance being aqueous ammonia.

6. The vehicle-mounted flame-retardant optical cable according to claim 1, characterized in that: The outer sheath is a ceramic sheath, and the ceramic sheath forms a ceramic skeleton structure at 500°C.

7. The vehicle-mounted flame-retardant optical cable according to claim 6, characterized in that: The ceramic sheath comprises base silicone rubber, zirconium silicate, magnesium hydroxide, red phosphorus masterbatch and peroxide DCP.

8. A method for preparing a vehicle-mounted flame-retardant optical cable, for preparing the vehicle-mounted flame-retardant optical cable as claimed in any one of claims 1 to 7, characterized in that: The steps include: S1. Select reinforcement members and perform surface treatment on the reinforcement members; S2. Applying a flame retardant coating on the outer periphery of the reinforcement; S3, traction light unit, reinforcement member twisted along the axial direction of the light unit; S4. Extruding an outer sheath around the twisted structure of the reinforcement member and the optical unit to obtain a vehicle-mounted flame-retardant optical cable.

9. The method for preparing a vehicle-mounted flame-retardant optical cable according to claim 8, characterized in that: Step S2 includes: ammonium octamolybdate, basic copper carbonate and ammonia water are selected according to a set ratio, and the ammonium octamolybdate, basic copper carbonate and ammonia water are added into a stirring device for stirring and mixing to obtain a flame retardant solution; Add the flame retardant solution to the dipping tank and pull the reinforcement through the dipping tank. The reinforcement is immersed in the dipping tank for 10 to 15 seconds. Use a hot air gun to blow the surface of the reinforcement to remove excess flame retardant solution on the surface of the reinforcement. The reinforcement coated with the flame retardant solution is placed into the first heating chamber at a temperature of 50-80°C for 1-3 hours. The reinforcement member that has passed through the first heating chamber is sent to the second heating chamber, with a heating temperature of 80-100°C and a heating time of 1h-3h; The reinforcement is naturally cooled to room temperature to obtain a reinforcement with a flame retardant coating.

10. The method for preparing a vehicle-mounted flame-retardant optical cable according to claim 8, wherein: Step S4 includes: The magnesium hydroxide and zirconium silicate are placed in an oven at 80-100°C for 2-3 hours to remove moisture from the magnesium hydroxide and zirconium silicate, and the mixture is set aside; the base silicone rubber is plasticized using an internal mixer at a plasticizing temperature of 60-80°C and a plasticizing time of 3-5 minutes; the zirconium silicate and magnesium hydroxide are sequentially added to the internal mixer and mixed for 5-8 minutes until the zirconium silicate and magnesium hydroxide are evenly dispersed in the base silicone rubber; the red phosphorus masterbatch and peroxide DCP are added to the internal mixer and mixed for another 4-6 minutes to obtain a rubber compound; the rubber compound is sheeted and cut to obtain a ceramic sheath material; The ceramic sheath material is added to the extruder, and the reinforcing member and the optical unit twisted structure are pulled through the extrusion die, and the ceramic sheath is formed on the outer periphery of the reinforcing member and the optical unit twisted structure; The formed ceramic sheath passes through the first section of the vulcanization tank at a vulcanization temperature of 160-180°C to obtain a ceramic sheath of a set shape; The ceramic sheath is passed through a drying device at 200-220°C to obtain a vehicle-mounted flame-retardant optical cable.

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