Novel butterfly-shaped splayed optical cable

Abstract

The present application relates to the technical fields of communication cable, and discloses a new type of vehicle-mounted butterfly-shaped splayed optical cable, which has a butterfly-shaped splayed integrated flat structure in the overall cross section, and comprises two parallel outer sheaths (3), connecting sections (4) connected with the outer sheaths (3), reinforcing units (2) located inside each outer sheath (3), and transmission units (1) covered by the reinforcing units (2). The transmission unit (1) is composed of a bending-resistant multi-mode optical fiber (11) and a tight sleeve layer (12), and the tight sleeve layer (12) covers the TPU bending-resistant multi-mode optical fiber (11). The present application also discloses a preparation method. The present application has the following main beneficial effects: the high and low temperature storage performance is greatly improved, the bending resistance is better, the flame retardant performance and transmission reliability are greatly improved, the laying adaptability and comprehensive protection are better, the production is easier, the miniaturization and light weight are better, and the cost is lower.

Description

Technical Field

[0001] This invention relates to the field of optical fiber communication technology, and in particular to a novel vehicle-mounted butterfly-shaped figure-eight optical fiber cable. The product is an optical fiber communication cable adapted to automotive scenarios, mainly used in intelligent and connected vehicle systems to achieve high-speed and stable signal transmission between vehicle devices. It is required to have excellent environmental resistance, mechanical properties and laying adaptability to meet the complex operating conditions of vehicles. Background Technology

[0002] Existing technology discloses a figure-eight shaped optical cable with an overall cross-section resembling the number 8. It comprises two parallel optical units, a connecting rib linking the two units, and an outer sheath. Each optical unit consists of optical fiber, a loose tube, and internal water-blocking material. The sheath is made of ordinary polyethylene or polyvinyl chloride. An FRP (fiberglass reinforced plastic) reinforcement is installed within the connecting rib. The entire cable is integrally formed using an extrusion process and is primarily used in conventional communication scenarios such as indoor cabling and overhead access networks. The two optical units are independent and arranged in parallel, their relative positions fixed by the connecting rib. The sheath completely covers the optical units and the connecting rib, with the reinforcement embedded within the connecting rib to improve tensile strength. All parts are formed into an integrated structure through an extrusion process. The sheath is made of PE and PVC materials, which have poor high and low temperature resistance, and are only suitable for temperatures ranging from -20℃ to 85℃. It cannot withstand the extreme temperature changes in the automotive environment, from -40℃ to 125℃, or the requirements for long-term storage. The materials themselves have low bending fatigue strength, and are prone to cracking after frequent bending. They also have poor oil and aging resistance, and are susceptible to performance degradation from contact with automotive oil stains or prolonged exposure to vibration. The optical unit uses a loose tube and a filled structure, resulting in a large volume and poor flexibility. It does not employ a tight-buffered design, limiting its bending performance. The reinforcement structure is poorly designed, lacking matching reinforcement materials inside the tube, resulting in weak tensile and lateral compression resistance, making it difficult to adapt to the frequent bending and complex stress conditions in automotive environments. Product size and weight control are inadequate, leading to low space utilization. It also has poor scenario adaptability; the structure and material design are geared towards conventional communication scenarios, without considering the vibration and impact conditions in automotive environments. Long-term use in vehicles can easily lead to internal structural displacement, fiber damage, and excessive attenuation.

[0003] Existing technology discloses a vehicle-mounted optical cable with an overall circular single-tube structure containing multiple optical fibers. A tight-buffered layer, a buffer layer, and a reinforcing layer are sequentially arranged on the outer side of each fiber. The outermost layer uses a common thermoplastic polyurethane (TPU) material as a sheath. The reinforcing layer uses an aramid fiber braided structure. The sheath only provides basic protection, and the material formulation has not been specially modified, making it suitable for conventional vehicle communication environments. Each protective layer is coaxially wrapped from the inside out, with the reinforcing layer surrounding the buffer layer and the sheath layer covering the outermost layer, forming a coaxial circular structure. This multi-layered protection achieves protection for the optical fibers. However, the cable uses a common TPU formulation, a standard commercial grade, lacking precise component ratios and functional modification design. It does not feature molecular chain, hard and soft segment structure design, or synergistic modification specifically for vehicle operating conditions, failing to meet the stringent requirements of long-term storage at 125℃ and stable use at -40℃. Its bending resistance is generally poor, making it difficult to achieve tens of thousands of repeated bends at small radii, and it lacks flame-retardant design, resulting in insufficient safety. The circular single-tube structure requires the installation of two optical cables to meet the needs of dual-channel signal transmission, which occupies a large space and is difficult to lay and fix. It does not adopt a flat design with a butterfly shape, resulting in low space utilization. There is no independent reinforcement material inside the tube, resulting in insufficient protection and tensile strength. The product size and weight have not been carefully designed, resulting in poor adaptability. The additional attenuation control under various operating conditions is not good, resulting in insufficient signal transmission stability. Summary of the Invention

[0004] This invention aims to overcome the deficiencies in the aforementioned background technology, solving technical problems such as insufficient high and low temperature storage performance, weak bending resistance, inadequate oil resistance and flame retardancy, poor structural adaptability, unreasonable size and weight, and excessive additional attenuation in existing optical cables. It achieves superior performance by allowing the optical cable to be stored for 3000 hours at 125℃ and 96 hours at -40℃, and to withstand 10,000 repeated bends at a 20D bending radius, with additional attenuation less than 0.5dB under all test conditions. Simultaneously, through refined size and weight design, it adapts to the requirements of installation in confined vehicle spaces, ensuring the stability and reliability of vehicle communication signal transmission. This invention discloses a novel vehicle-mounted butterfly-shaped figure-eight optical cable, which is implemented using the following technical solution.

[0005] A novel vehicle-mounted butterfly-shaped optical cable is characterized by having an integrated flat structure with a butterfly-shaped cross-section, comprising two parallel outer sheaths, a connecting section connecting the outer sheaths, an enhancement unit located inside each outer sheath, and a transmission unit covered by the enhancement unit; the transmission unit consists of a bend-resistant multimode optical fiber and a tight-buffered layer, with the tight-buffered layer covering the TPU bend-resistant multimode optical fiber.

[0006] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the outer sheath is made of modified polyether TPU, which, by weight, is composed of the following raw materials: 70-85 parts of polyether TPU resin, 0.5-1 parts of antioxidant, 0.5-2 parts of lubricant, 10-15 parts of halogen-free flame retardant, and 5-10 parts of modifier.

[0007] The novel vehicle-mounted butterfly-shaped optical cable described in this application is characterized by its preparation method comprising the following steps: TPU tight-buffered fiber prefabrication: 90A polyether TPU of grade 1076S is fed into a special extruder and melted at 180℃~200℃. The tight-buffered layer is uniformly extruded on the outside of the bending-resistant multimode optical fiber, and the overall outer diameter is controlled to be about 0.9mm and the thickness of the tight-buffered layer is about 0.3mm. After cooling and shaping, it is wound up for later use. Preparation of modified outer sheath material: Weigh 70-85 parts of polyether TPU resin, 0.5-1 parts of composite antioxidant, 0.5-2 parts of lubricant, 10-15 parts of halogen-free flame retardant, and 5-10 parts of modifier according to the formula ratio. First, premix the mixture in a high-speed mixer at 60℃-80℃ for 5-10 minutes, then add it to a twin-screw extruder and melt-blend, extrude, and water-cool and pelletize it to produce a special modified polyether TPU material. The moisture content of the material is strictly controlled to be ≤500ppm throughout the process. Integrated extrusion molding: Two pre-made TPU tight-buffered fibers and 3-5 aramid fibers per group are simultaneously fed into a butterfly-shaped figure-eight special extrusion die. The aramid fibers are evenly distributed on the outside of the tight-buffered fibers, and the linear density is controlled at 800-1500 Dtex. The modified outer sheath material is melted by an extruder and injected into the die for one-time encapsulation molding. The outer diameter of a single outer sheath is controlled to not exceed 2.0 mm, the width of the entire cable is not more than 4.0 mm, the traction speed is 25-40 m / min, and after cooling and shaping, it is wound up to obtain a flat butterfly-shaped figure-eight finished optical cable with a nominal weight of 14 kg / km.

[0008] The present invention has the following main advantages: significantly improved high and low temperature storage performance, better bending resistance, significantly improved flame retardant performance and transmission reliability, better laying adaptability and comprehensive protection, easier production, smaller and lighter size, and lower cost. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the cross-sectional structure of the present invention. Detailed Implementation

[0010] To enable those skilled in the art to better understand and implement this patent, the markings in the accompanying drawings are explained in detail below.

[0011] In the diagram: 1—transmission unit, 2—enhancing unit, 3—outer sheath, 4—connector section, 11—bending-resistant multimode fiber, 12—tight-buffered layer.

[0012] Please see Figure 1 A novel vehicle-mounted butterfly-shaped figure-eight optical cable is characterized by having an integrated flat structure with a butterfly-shaped figure-eight cross-section, comprising two parallel outer sheaths 3, a connecting section 4 connecting the outer sheaths 3, an enhancement unit 2 located inside each outer sheath 3, and a transmission unit 1 covered by the enhancement unit 2; the transmission unit 1 is composed of a bending-resistant multimode optical fiber 11 and a tight-buffered layer 12, with the tight-buffered layer 12 covering the TPU bending-resistant multimode optical fiber 11.

[0013] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the transmission unit 1 is a TPU tight-buffered fiber.

[0014] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the tight-buffered layer 12 is made of 90A polyether TPU, grade 1076S.

[0015] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the nominal diameter of the tight-buffered layer 12 is 0.9 mm and the nominal thickness is 0.3 mm.

[0016] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the reinforcing unit 2 is made of aramid fiber.

[0017] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the number of aramid fibers is 3 to 5, and the linear density of the aramid fibers is 800 to 1500 Dtex.

[0018] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the outer sheath 3 is made of modified polyether TPU, which is composed of the following raw materials by weight: 70-85 parts of polyether TPU resin, 0.5-1 parts of antioxidant, 0.5-2 parts of lubricant, 10-15 parts of halogen-free flame retardant, and 5-10 parts of modifier.

[0019] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the antioxidant is composed of antioxidant of type 1010 and antioxidant of type 168, compounded in a weight ratio of 1:1 to 2:1.

[0020] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the lubricant is a fatty acid ester or a silicone; for example, DuPont's MULTIBASE™ MB50-004.

[0021] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the halogen-free flame retardant is of high phosphorus content; for example: Clariant Exolit® OP945.

[0022] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the modifier is an acrylate copolymer or a styrene copolymer; for example: SEPTON™ 8851.

[0023] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the connecting section 4 and the outer sheath 3 are an integral structure and are made of the same material.

[0024] The novel vehicle-mounted butterfly-shaped optical cable described above is characterized in that the outer diameter of a single outer sheath 3 does not exceed 2.0 mm; the width of the entire cable does not exceed 4.0 mm; and the nominal unit weight of the entire cable is 14 kg / km.

[0025] In this application, the outer sheath 3 is made of modified polyether TPU. The outer sheath and the connecting section are formed in one step by extrusion process to form a flat and integrated structure with regular contours. Each outer sheath unit is independently configured with transmission and enhancement components. The structural layers are closely matched to achieve precise protection and performance enhancement of the internal optical fiber.

[0026] In this application, aramid fibers are evenly distributed along the optical cable axis on the outer periphery of the TPU tight-buffered fiber, in close contact with the tight-buffered fiber, and are jointly covered by the outer sheath 3.

[0027] In this application, TPU tight-buffered fiber is directly wrapped around the outside of the optical fiber; the excellent flexibility and low temperature resistance of the TPU tight-buffered material itself provide direct protection for the optical fiber, while ensuring its adaptability when bending and controlling transmission attenuation.

[0028] In this application, aramid fiber possesses high strength, high toughness, and resistance to high and low temperatures, forming an internal reinforcing skeleton within the outer sheath. This significantly improves the tensile strength, lateral pressure resistance, and bending resistance of the single tube, forming a dual reinforcement system with the external protective structure. At the same time, the specifications are strictly controlled to fit the overall dimensions.

[0029] In this application, aramid fibers are uniformly arranged around the TPU tight-fitting fibers in the circumferential direction, with no gaps between them; the two outer sheath units are fixed in relative position by a connecting section, and the overall structure is free from looseness and relative displacement, with dimensional accuracy controlled within ±0.1mm.

[0030] In this application, the three formulation components of the outer sheath are precisely matched to achieve synergistic improvement in multiple performance aspects.

[0031] In this application, the polyether-type TPU resin in the outer sheath 3 uses high molecular weight polytetrahydrofuran ether (PTMEG) as the soft segment component. The ether bonds in this molecular chain have a low internal rotational energy barrier and high chain segment freedom, endowing the material with excellent low-temperature resistance from the molecular structure perspective. This allows the material to maintain good flexibility and elasticity even after long-term storage at -40℃, without cracking or hardening. Simultaneously, the high molecular weight soft segment improves the material's elongation at break and fatigue resistance, meeting the requirements for repeated bending up to 10,000 cycles. The hard segment uses a chain extension reaction with the introduction of high-rigidity aromatic isocyanate (MDI) combined with 1,4-butanediol (BDO) as a chain extender, forming highly crystalline urethane groups. These groups can form stable physical cross-linking points within the material, significantly improving the modulus retention and dimensional stability at high temperatures. It can withstand long-term storage at 125℃ for 3000 hours without softening or deformation, while also forming a dense molecular structure, giving the material excellent oil barrier properties and preventing oil molecule penetration. By precisely controlling the feeding ratio of soft and hard segments and the sequence structure distribution during the polymerization process, and with the addition of modifiers (acrylate copolymers or styrene copolymers), the hardness of the TPU outer sheath material is ultimately stably controlled within the range of 88±3A (i.e., 85A~91A). The addition of modifiers further optimizes the intermolecular forces, improves the processing fluidity and structural stability of the material. This hardness range is the optimal balance range, which retains sufficient flexibility to meet the needs of frequent bending, while also possessing sufficient structural strength and temperature resistance stability, achieving a synergistic balance between flexibility, temperature resistance and mechanical properties, and adapting to the mechanical properties of the butterfly-shaped flat structure.

[0032] In this application, among the composite antioxidants in the outer sheath 3, 1010 is a high molecular weight hindered phenolic antioxidant that provides long-term thermal stability protection; 168 is a phosphite antioxidant that decomposes hydrogen peroxide and synergistically inhibits the molecular chain degradation of the material under high temperature and high humidity conditions, ensuring the thermal stability of long-term storage and use.

[0033] In this application, a lubricant is added to the outer sheath 3 to reduce intermolecular friction and processing viscosity, improve material flowability and demolding properties, ensure dimensional accuracy and smooth surface during extrusion molding, and reduce performance loss during processing.

[0034] In this application, a halogen-free flame retardant with high phosphorus content is used, with the addition amount controlled at 10-15 parts. The compatibility with the matrix is ​​improved through surface treatment, and a continuous flame retardant layer is formed inside the material to achieve halogen-free flame retardancy. While meeting safety requirements, the low addition amount preserves the physical and mechanical properties of the material to the greatest extent.

[0035] In this application, a composite modifier (acrylate copolymer or styrene copolymer) is added to improve the toughness, weather resistance and structural uniformity of the material, further enhance its bending resistance and fatigue resistance, and optimize its bonding performance with internal components.

[0036] Testing revealed that the outer sheath of this application has a hardness of 85A to 91A; a long-term operating temperature range of -40℃ to 125℃; an elongation at break ≥600%; a bending resilience ≥92%; a flame retardant rating of UL94 V-0; and oil resistance meeting the requirements of GB / T 1690 standard. The outer sheath has a uniform thickness, ranging from 0.6 to 0.8 mm, forming a seamless, sealed protective layer with a smooth outer surface, suitable for snap-fit ​​installation.

[0037] The novel vehicle-mounted butterfly-shaped optical cable described in this application is characterized by its preparation method comprising the following steps: TPU tight-buffered fiber prefabrication: 90A polyether TPU of grade 1076S is fed into a special extruder and melted at 180℃~200℃. The tight-buffered layer is uniformly extruded on the outside of the bending-resistant multimode optical fiber, and the overall outer diameter is controlled to be about 0.9mm and the thickness of the tight-buffered layer is about 0.3mm. After cooling and shaping, it is wound up for later use. Preparation of modified outer sheath material: Weigh 70-85 parts of polyether TPU resin, 0.5-1 parts of composite antioxidant, 0.5-2 parts of lubricant, 10-15 parts of halogen-free flame retardant, and 5-10 parts of modifier according to the formula ratio. First, premix the mixture in a high-speed mixer at 60℃-80℃ for 5-10 minutes, then add it to a twin-screw extruder and melt-blend, extrude, and water-cool and pelletize it to produce a special modified polyether TPU material. The moisture content of the material is strictly controlled to be ≤500ppm throughout the process. Integrated extrusion molding: Two pre-made TPU tight-buffered fibers and 3-5 aramid fibers per group are simultaneously fed into a butterfly-shaped figure-eight special extrusion die. The aramid fibers are evenly distributed on the outside of the tight-buffered fibers, and the linear density is controlled at 800-1500 Dtex. The modified outer sheath material is melted by an extruder and injected into the die for one-time encapsulation molding. The outer diameter of a single outer sheath is controlled to not exceed 2.0 mm, the width of the entire cable is not more than 4.0 mm, the traction speed is 25-40 m / min, and after cooling and shaping, it is wound up to obtain a flat butterfly-shaped figure-eight finished optical cable with a nominal weight of 14 kg / km.

[0038] After testing, the overall performance indicators of the optical cable in this invention are as follows: Dimensions and weight: Overall cable width ≤ 4.0mm, single tube outer diameter ≤ 2.0mm; unit weight approximately 14kg / km; TPU tight-buffered fiber outer diameter approximately 0.9mm, tight-buffered layer thickness approximately 0.3mm; 3-5 aramid fibers per tube, linear density 800-1500Dtex.

[0039] High and low temperature storage performance: After 3000 hours of storage at 125℃ and 96 hours of storage at -40℃, there is no deformation or cracking in appearance, and the additional attenuation is less than 0.5dB.

[0040] Bending resistance: Bending radius 20D (D is the maximum diameter of the optical cable), 10,000 reciprocating bends, no cracking of the sheath, no damage to the outer sheath, no breakage of the aramid fiber, and additional attenuation less than 0.5dB.

[0041] Other properties: tensile strength ≥150N; vibration resistance up to 10g, vibration frequency 10~2000Hz, additional attenuation less than 0.5dB after 200h; oil resistance: after immersion in the test oil specified in GB / T 1690 standard for 72h, the change rate of tensile strength ≤8%; flame retardant performance: overall reaches halogen-free flame retardant UL94 V-0 level; additional attenuation is consistently less than 0.5dB under all test conditions.

[0042] In this invention, the soft segment of the outer sheath uses high molecular weight PTMEG, which, thanks to the molecular characteristics of low internal rotational energy barrier of ether bonds, ensures flexibility for long-term storage at -40℃ from the source; the hard segment uses an MDI+BDO system to form highly crystalline urethane physical cross-linking points, ensuring modulus and dimensional stability for 3000 hours of storage at 125℃, while also enhancing oil barrier properties; the addition of modifiers precisely controls the hardness to 88±3A, adapting to the mechanical properties of the flat structure, supporting 10,000 repeated bends at a radius of 20D, with an additional attenuation of less than 0.5dB under all operating conditions.

[0043] Key points of synergistic modification: Thermally stable system: 1010 and 168 are compounded to provide long-lasting antioxidant synergy and solve the degradation problem of polyether TPU; Processing system: Lubricant optimization improves molding precision and surface quality; Flame retardant system: Low addition amount of halogen-free flame retardant, meets safety standards and retains basic performance; Structural modification: Acrylic ester / styrene copolymers improve toughness and uniformity, ensuring long-term stability.

[0044] The present invention has the following beneficial effects: (a) Improvement of material properties: High and low temperature storage performance: Through precise formulation and molecular chain design, the soft segment PTMEG ensures low temperature and the hard segment crosslinking ensures high temperature. This invention can achieve long-term storage of 3000 hours at 125℃ and 96 hours at -40℃, with additional attenuation of less than 0.5dB. Existing technology 1 is applicable to temperatures of -20℃ to 85℃, softens after 500 hours of high-temperature storage and cracks after 24 hours of low-temperature storage, with excessive attenuation. Existing technology 2 is applicable to temperatures of -30℃ to 100℃, with performance degradation of ≥40% after 1000 hours. This invention achieves a qualitative breakthrough.

[0045] Test conditions: High and low temperature test chamber, accuracy ±2℃, after constant temperature placement, the appearance, mechanical properties and attenuation are tested.

[0046] Bending resistance: Through optimized formulation and structural reinforcement, this invention can withstand 10,000 repeated bends at a bending radius of 20D with an additional attenuation of less than 0.5dB. Existing technology 1 cracks after 2,800 bends at 30D with an attenuation of >1.0dB; Existing technology 2 cracks after 3,200 bends at 25D with an attenuation of <0.8dB. This invention has a smaller bending radius and more than doubles the number of bends, resulting in more stable transmission.

[0047] Test conditions: Bending test machine, ±90°, 60 times / min. After the test, the outer sheath, structure and attenuation were inspected.

[0048] Other performance characteristics: The precise formula of the outer sheath achieves halogen-free flame retardant UL94 V-0 rating, while existing technologies lack flame retardant design; the oil resistance test strength change rate is ≤8%, which is better than existing technology 1 (≥30%) and existing technology 2 (≥20%); the additional attenuation under all working conditions is stable at less than 0.5dB, which is far better than the attenuation level of the background technology, and the transmission reliability is greatly improved.

[0049] (II) Structural and Usage Advantages: Laying adaptability: The butterfly-shaped flat design has a total cable width of ≤4.0mm and a weight of about 14kg / km. The cross-sectional area is reduced by about 35% compared to the circular dual-core cable, and the weight is reduced by about 25%. It can be directly inserted into the flat cable channel of the vehicle body, improving installation efficiency by more than 40% and making it suitable for narrow spaces.

[0050] Comprehensive protective performance: The outer sheath is reinforced with 3-5 aramid fibers and modified, with a tensile strength of 150N, which is 50% and 25% higher than existing technologies 1 (100N) and 2 (120N) respectively; Vibration resistance 10g, additional attenuation after 200h <0.5dB, while existing technology attenuation >0.5dB; With its independent outer sheath design, damage to one circuit does not affect the other, resulting in higher reliability.

[0051] (III) Cost and process effect: Precise formulation and structural design increase raw material costs by ≤8%, but improve integrated extrusion efficiency by about 18%, making it compatible with existing production lines; miniaturization and lightweighting reduce transportation and construction costs, extend service life by about 50%, reduce total life cycle costs, and have value for large-scale promotion.

[0052] (iv) Analysis of theoretical effects: From the perspective of materials science and mechanics, this invention adopts a five-layer logic of "precise formulation - molecular design - synergistic modification - parameter refinement - structural innovation": ① precise formulation ratio to balance multiple properties; ② molecular structure to break through temperature resistance boundaries; ③ synergistic superposition of multiple additives; ④ parameter refinement to adapt to automotive requirements; ⑤ flat structure to optimize stress and installation; ultimately achieving an additional attenuation of less than 0.5dB under all working conditions, comprehensively surpassing existing technologies and perfectly adapting to the stringent requirements of automotive applications.

[0053] This application can also be used as a smart sensor or smart sensing element; since it can transmit voice and images, it can also be used as a physical sensor, such as a voice sensor or an image sensor; since it transmits light signals through the principle of total internal reflection, it can also be used as a distance sensor; the optical fiber in this application is itself an optical waveguide, so it can be used as an optical waveguide, such as an arrayed optical waveguide or a diffractive optical waveguide; this application can also be used in the field of optical computing, as part of optical chip computing, optical computing, optical network computing, and optical computing.

[0054] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A novel vehicle-mounted butterfly-shaped figure-eight optical cable, characterized in that, The overall cross section is a butterfly-shaped figure-eight integrated flat structure with two parallel outer sheaths (3), a connecting section (4) connecting the outer sheaths (3), an enhancement unit (2) located inside each outer sheath (3), and a transmission unit (1) covered by the enhancement unit (2). The transmission unit (1) is composed of a bending-resistant multimode fiber (11) and a tight-buffered layer (12), with the tight-buffered layer (12) covering the TPU bending-resistant multimode fiber (11).

2. The novel vehicle-mounted butterfly-shaped figure-eight optical cable according to claim 1, characterized in that, The transmission unit (1) is a TPU tight-buffered fiber.

3. A novel vehicle-mounted butterfly-shaped figure-eight optical cable according to claim 2, characterized in that, The material of the tight-fitting layer (12) is 90A polyether TPU, grade 1076S.

4. A novel vehicle-mounted butterfly-shaped figure-eight optical cable according to claim 3, characterized in that, The nominal diameter of the tight-fitting layer (12) is 0.9 mm and the nominal thickness is 0.3 mm.

5. A novel vehicle-mounted butterfly-shaped figure-eight optical cable according to claim 1, characterized in that, The material of the reinforcing unit (2) is aramid fiber.

6. A novel vehicle-mounted butterfly-shaped figure-eight optical cable according to claim 5, characterized in that, The number of aramid fibers is 3 to 5, and the linear density of aramid fibers is 800 to 1500 Dtex.

7. A novel vehicle-mounted butterfly-shaped figure-eight optical cable according to claim 1, characterized in that, The outer sheath (3) is made of modified polyether TPU, which is composed of the following raw materials by weight: 70-85 parts of polyether TPU resin, 0.5-1 parts of antioxidant, 0.5-2 parts of lubricant, 10-15 parts of halogen-free flame retardant, and 5-10 parts of modifier.

8. A novel vehicle-mounted butterfly-shaped figure-eight optical cable according to claim 1, characterized in that, The antioxidant is a mixture of antioxidant type 1010 and antioxidant type 168, in a weight ratio of 1:1 to 2:

1.

9. A novel vehicle-mounted butterfly-shaped figure-eight optical cable according to claim 8, characterized in that, The lubricant is a fatty acid ester or silicone; the halogen-free flame retardant is a high-phosphorus type; the modifier is an acrylate copolymer or a styrene copolymer.

10. A novel vehicle-mounted butterfly-shaped figure-eight optical cable according to claim 1, characterized in that, The preparation method includes the following steps: TPU tight-buffered fiber prefabrication: 90A polyether TPU of grade 1076S is fed into a special extruder and melted at 180℃~200℃. The tight-buffered layer is uniformly extruded on the outside of the bending-resistant multimode optical fiber, and the overall outer diameter is controlled to be about 0.9mm and the thickness of the tight-buffered layer is about 0.3mm. After cooling and shaping, it is wound up for later use. Preparation of modified outer sheath material: Weigh 70-85 parts of polyether TPU resin, 0.5-1 parts of composite antioxidant, 0.5-2 parts of lubricant, 10-15 parts of halogen-free flame retardant, and 5-10 parts of modifier according to the formula ratio. First, premix the mixture in a high-speed mixer at 60℃-80℃ for 5-10 minutes, then add it to a twin-screw extruder and melt-blend, extrude, and water-cool and pelletize it to produce a special modified polyether TPU material. The moisture content of the material is strictly controlled to be ≤500ppm throughout the process. Integrated extrusion molding: Two pre-made TPU tight-buffered fibers and 3-5 aramid fibers per group are simultaneously fed into a butterfly-shaped figure-eight special extrusion die. The aramid fibers are evenly distributed on the outside of the tight-buffered fibers, and the linear density is controlled at 800-1500 Dtex. The modified outer sheath material is melted by an extruder and injected into the die for one-time encapsulation molding. The outer diameter of a single outer sheath is controlled to not exceed 2.0 mm, the width of the entire cable is not more than 4.0 mm, the traction speed is 25-40 m / min, and after cooling and shaping, it is wound up to obtain a flat butterfly-shaped figure-eight finished optical cable with a nominal weight of 14 kg / km.

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