A large-core high-density temperature-resistant and flame-retardant communication optical cable and a preparation method thereof

Abstract

The application discloses a large-core high-density temperature-resistant flame-retardant communication optical cable and a preparation method thereof, and relates to the technical field of optical cables.The application discloses a large-core high-density temperature-resistant flame-retardant communication optical cable, which comprises a middle reinforcing member, an optical fiber transmission layer, a wrapping tape layer and a sheath layer; the optical fiber transmission layer and the wrapping tape layer are alternately wrapped around the outer periphery of the middle reinforcing member; and the sheath layer is wrapped around the outer periphery of the optical fiber transmission layer.The optical fiber transmission layer is composed of a plurality of optical fiber unit modules; and the optical fiber unit module is prepared by twisting a plurality of optical fiber bundles and then extruding an inner sheath layer on the surface of the optical fiber bundles.The temperature-resistant flame-retardant communication optical cable prepared by the application solves the problems of low core density, poor environmental adaptability and difficult construction and maintenance of traditional optical cables, has the advantages of high density, high reliability, easy deployment and full-scene adaptation, and is suitable for high-speed interconnection of data centers and computing clusters in intelligent computing parks.

Description

Technical Field

[0001] This invention relates to the field of optical cable technology, specifically to a high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable and its preparation method. Background Technology

[0002] With the rapid development of artificial intelligence, big data, cloud computing, and intelligent computing centers, the amount of data interaction within intelligent computing parks is growing exponentially, placing extremely high demands on the bandwidth, capacity, density, and deployment flexibility of optical transmission networks. Traditional outdoor optical cables typically have 144-288 cores, with a few reaching 576 cores, which is insufficient for high-density interconnection scenarios with over 1000 cores. Multiple laying operations are required during construction to meet the usage requirements of the computing center in the intelligent computing park. In terms of product structure, indoor optical cables prioritize flexibility and flame retardancy, while outdoor optical cables emphasize weather resistance, pressure resistance, and waterproofing. Traditional optical cables are difficult to use universally both indoors and outdoors, requiring frequent switching during cross-scenario laying, increasing link loss and potential failure points. Regarding performance assurance, optical cables within intelligent computing parks need to traverse various scenarios such as computer rooms, pipelines, outdoor trenches, and overhead installations. The pressure resistance, bending resistance, and tensile strength of traditional optical cables are insufficient to adapt to complex laying environments, easily leading to fiber breakage and excessive attenuation.

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an indoor and outdoor optical cable for interconnecting smart computing parks. This invention solves the problems of low core density, poor indoor and outdoor versatility, difficult construction and maintenance, and insufficient mechanical protection of traditional optical cables, and achieves high-density integration with ultra-large core count to meet the interconnection needs of complex scenarios in smart computing parks. Summary of the Invention

[0004] The purpose of this invention is to provide a high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable and its preparation method, thereby solving the following technical problems:

[0005] Existing optical cables cannot be adapted to high-density interconnection scenarios with more than 1,000 cores, and are difficult to be compatible with the needs of both indoor and outdoor use.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable, comprising:

[0008] Intermediate reinforcement;

[0009] An optical fiber transmission layer, with multiple optical fiber transmission layers sequentially wrapped around the outer periphery of the intermediate reinforcing member;

[0010] The wrapping layer is disposed between two adjacent optical fiber transmission layers;

[0011] Sheath layer, which covers the outermost optical fiber transmission layer;

[0012] The sheath layer comprises the following raw materials in parts by weight: 60-70 parts high-density polyethylene, 10-15 parts toughening agent, 28-40 parts flame retardant, 4-6 parts UV stabilizer, 0.5-0.8 parts antioxidant, 0.5-1 parts calcium stearate, and 0.5-1.5 parts boron-containing crosslinking agent.

[0013] The toughening agent is an ethylene-octene copolymer elastomer;

[0014] The flame retardant consists of 8-12 parts by weight of hyperbranched modified sepiolite and 20-28 parts by weight of core-shell microencapsulated phosphorus-nitrogen flame retardant;

[0015] Hyperbranched modified sepiolite is prepared by reacting sepiolite with aluminum dihydrogen phosphate and then with an amino-terminated hyperbranched polymer.

[0016] The core-shell microencapsulated phosphorus-nitrogen flame retardant consists of, from the inside out, a phosphorus-nitrogen flame retardant core, a borosilicate cross-linked intermediate layer, and a maleic anhydride-grafted polyethylene wax outer shell.

[0017] The UV stabilizer consists of a conductive carbon black core, a silica intermediate layer, and a KH570 silane coupling agent organic outer layer, from the inside out.

[0018] As a further aspect of the present invention: the thickness of the sheath layer is 1-3 mm.

[0019] As a further aspect of the present invention, the preparation method of hyperbranched modified sepiolite includes the following steps:

[0020] A1: Add acid-activated sepiolite, aluminum dihydrogen phosphate, and deionized water to a reaction flask, control the temperature at 80-90℃, and keep the reaction at this temperature for 3-6 hours under stirring. After centrifugation, washing, and drying, aluminum dihydrogen phosphate-modified sepiolite is obtained.

[0021] A2: Under a nitrogen atmosphere, aluminum dihydrogen phosphate modified sepiolite and xylene were added to a reaction flask and dispersed. Then, terminal amino hyperbranched polymer and p-toluenesulfonic acid were added. The temperature was controlled at 130-140℃ and the reaction was refluxed for 6-9 hours. Xylene was removed by vacuum distillation, and the mixture was washed with acetone and dried to obtain hyperbranched modified sepiolite.

[0022] The addition ratio of acid-activated sepiolite, aluminum dihydrogen phosphate, and deionized water in A1 is 100g: 15-25g: 300-500mL.

[0023] The addition ratio of aluminum dihydrogen phosphate modified sepiolite, xylene, terminal amino hyperbranched polymer, and p-toluenesulfonic acid in A2 is 100g: 300-500mL: 20-30g: 0.5-1g;

[0024] The amino-terminated hyperbranched polymers are hyperbranched polyamide-amine PAMAM or hyperbranched poly(hydroxymethylphosphonic oxide) phosphonate PHPOP.

[0025] The preparation method of core-shell microencapsulated phosphorus-nitrogen flame retardant includes the following steps:

[0026] B1: Disperse 3-6g of hexadecyltrimethylammonium bromide, 250-350mL of anhydrous ethanol, and 25-35mL of deionized water in a reaction flask. Add 100g of ammonium polyphosphate for dispersion and adjust the pH to 8.5-9.5. Add 20-30g of tetraethyl orthosilicate and 5-10g of tributyl borate to the reaction flask. Maintain the reaction temperature at 40-60℃ and stir for 4-8 hours. Centrifuge, wash, and dry to obtain a solid. Reflux the solid with acidified ethanol solution to remove hexadecyltrimethylammonium bromide. Wash and dry to obtain an intermediate.

[0027] B2: Under a nitrogen atmosphere, maleic anhydride-grafted polyethylene wax and xylene are added to a reaction flask. The temperature is controlled at 120-135℃, and the mixture is stirred and dissolved. An intermediate is added and dispersed. The mixture is kept at a constant temperature for 2-4 hours under stirring. After centrifugation, washing, and drying, a core-shell microencapsulated phosphorus-nitrogen flame retardant is obtained.

[0028] The addition ratio of hexadecyltrimethylammonium bromide, anhydrous ethanol, deionized water, ammonium polyphosphate, tetraethyl orthosilicate, and tributyl borate in B1 is 3-6g: 250-350mL: 25-35mL: 100g: 20-30g: 5-10g;

[0029] In B2, the addition ratio of maleic anhydride-grafted polyethylene wax, xylene, and intermediates is 10-18g: 200-300mL: 100g.

[0030] As a further embodiment of the present invention: the acidified ethanol solution in B1 is composed of 400-600 mL of anhydrous ethanol, 5-10 mL of 36-38 wt% concentrated hydrochloric acid, and 20-40 mL of deionized water.

[0031] As a further aspect of the present invention, the specific steps of reflux extraction in B1 are as follows: control the temperature at 75-85℃ and reflux extract for 4-6 hours.

[0032] As a further aspect of the present invention, the preparation method of acid-activated sepiolite includes the following steps: placing sepiolite in hydrochloric acid solution, controlling the temperature at 30-50℃, and keeping the reaction at this temperature for 1-3 hours under stirring conditions, filtering, washing, and drying to obtain acid-activated sepiolite;

[0033] The hydrochloric acid solution is a 1-2 mol / L aqueous solution; the addition ratio of sepiolite to hydrochloric acid solution is 100g: 500-800mL.

[0034] As a further aspect of the present invention, the particle size of sepiolite is 10-45 μm.

[0035] As a further aspect of the present invention, the method for preparing the UV stabilizer includes the following steps:

[0036] C1: Carbon black and anhydrous ethanol are added to a reaction flask and dispersed. Tetraethyl orthosilicate is added and dispersed. Deionized water is added and the pH is adjusted to 9-10. The temperature is controlled at 35-50℃ and the reaction is kept at this temperature for 6-12 hours under stirring. After centrifugation, washing and drying, silica-coated carbon black is obtained.

[0037] C2: Add anhydrous ethanol and deionized water to the reaction flask for dispersion, adjust the pH to 4-5, add KH570 for dispersion, add silica to coat carbon black, control the temperature at 60-75℃ and keep the reaction at this temperature for 3-6 hours, centrifuge, wash and dry to obtain the UV stabilizer.

[0038] The addition ratio of carbon black, anhydrous ethanol, tetraethyl orthosilicate, and deionized water in C1 is 100g: 400-600mL: 30-50g: 40-60mL;

[0039] The addition ratio of anhydrous ethanol, deionized water, KH570, and silica-coated carbon black in C2 is 300-400mL: 20-30mL: 8-12g: 100g.

[0040] As a further aspect of the present invention: the antioxidant is composed of hindered phenolic antioxidant and phosphite antioxidant in a mass ratio of 1:1; the boron-containing crosslinking agent is triethanolamine borate or glycerol borate.

[0041] As a further aspect of the present invention, the preparation method of the sheath layer includes the following steps: blending high-density polyethylene and ethylene-octene copolymer elastomer toughening agent, blending flame retardant and UV stabilizer, adding boron-containing crosslinker and blending, adding antioxidant and calcium stearate and blending, extruding with a twin-screw extruder to obtain sheath layer masterbatch; extruding the sheath layer masterbatch on the surface of the optical fiber transmission layer to form a sheath layer.

[0042] As a further embodiment of the present invention: the intermediate reinforcing member is any one of the following: FRP reinforcing material, FRP reinforcing material with PP material extruded and foamed on the surface, or FRP reinforcing material with a sheath layer extruded on the surface. The FRP reinforcing material with PP material extruded and foamed on the surface solves the problem of excessive loss in the optical fiber unit module caused by the sheath material of the central reinforcing member under pressure conditions.

[0043] As a further embodiment of the present invention: the optical fiber transmission layer is composed of multiple optical fiber unit modules;

[0044] The fiber optic unit module is made by twisting one or more fiber bundles together and then extruding an inner sheath layer on the surface; a single fiber optic unit module contains 1-24 fiber bundles; the thickness of the inner sheath layer is 0.1-0.4 mm.

[0045] As a further aspect of the invention: the optical fiber bundle consists of 8-core or 16-core multiples of optical fibers, and the surface of the optical fiber bundle is provided with arrayed ink dots or wrapped with water-blocking yarn; the water-blocking polyester yarn is wound around the optical fiber bundle at a pitch of 10-20mm, and the release tension of the water-blocking polyester yarn is 20-30g. The water-blocking polyester yarn has a slight fixing effect on the surface of the optical fiber, while ensuring that the shrinkage performance of the water-blocking polyester yarn at high temperatures will not affect the optical fiber unit product. This achieves full water blocking in both the longitudinal and radial directions, adapting to outdoor humid and rainy environments, and preventing the problem of water infiltration leading to optical fiber attenuation. Different arrayed ink dots are set on the surface of different optical fiber bundles, serving a distinguishing function.

[0046] As a further embodiment of the present invention, a wrapping layer with an embedded tear cord is provided between the sheath layer and the outermost optical fiber transmission layer.

[0047] As a further aspect of the present invention, an FRP reinforcement is also embedded in the sheath layer, which can be used in harsh pipeline conditions.

[0048] As a further aspect of the present invention: the inner sheath layer comprises the following raw materials in parts by weight: 70-80 parts by weight of thermoplastic polyurethane elastomer, 5.5-10 parts by weight of friction-reducing modifier component, 10-15 parts by weight of flame retardant, 3-5 parts by weight of compatibilizer, and 0.4-0.7 parts by weight of antioxidant.

[0049] The friction-reducing modifier consists of epoxy silane-modified PTFE micro powder in a ratio of 5-8:0.5-2 and carboxyl-terminated modified fatty acid ester internal lubricant dispersant.

[0050] The antioxidant is composed of hindered phenolic antioxidants and phosphite antioxidants in a mass ratio of 0.3-0.5:0.1-0.2.

[0051] The flame retardant is phosphate ester coupling agent modified APP.

[0052] As a further aspect of the present invention, the thermoplastic polyurethane elastomer has a Shore hardness of 85-90A.

[0053] As a further embodiment of the present invention, the preparation method of phosphate ester coupling agent modified APP includes the following steps: APP and anhydrous ethanol are added to a reaction flask and dispersed evenly, isopropyl tris(dioctylpyrophosphoryloxy) titanate is added and dispersed, deionized water is added and dispersed, the temperature is controlled at 60-70℃ and the reaction is kept at a constant temperature for 2-4 hours under stirring, centrifugation, washing and drying are performed to obtain phosphate ester coupling agent modified APP.

[0054] The addition ratio of APP, anhydrous ethanol, isopropyl tris(dioctylpyrophosphoryloxy)titanate, and deionized water is 100g: 300-400mL: 3-8g: 5-10mL.

[0055] As a further embodiment of the present invention, the preparation method of epoxy silane modified PTFE micro powder includes the following steps: anhydrous ethanol and deionized water are added to a reaction flask and dispersed evenly; glacial acetic acid is added to adjust the pH of the system to 4.5-5.5; KH560 is added for dispersion and hydrolysis; pre-activated PTFE micro powder is added; the temperature is controlled at 65-75℃; the reaction is carried out under stirring conditions for 3-6 hours; centrifugation, filtration, washing, and drying are performed to obtain epoxy silane modified PTFE micro powder.

[0056] The addition ratio of anhydrous ethanol, deionized water, KH560, and preactivated PTFE micro powder is 280-320mL: 30-40mL: 4-6g: 100g.

[0057] As a further aspect of the present invention, the preparation method of pre-activated PTFE micro powder includes the following steps: surface etching activation of PTFE micro powder surface using low-temperature air plasma, discharge power 150-200W, processing time 8-12min, to obtain pre-activated PTFE micro powder; a large number of hydroxyl active sites are introduced into the inert PTFE surface to provide an active basis for silane grafting reaction.

[0058] As a further aspect of the present invention: the PTFE micro powder has a particle size of 1-5 μm.

[0059] As a further embodiment of the present invention, the preparation method of the carboxyl-terminated modified fatty acid ester internal lubricating dispersant includes the following steps: under a nitrogen atmosphere, pentaerythritol oleate and xylene are added to a reactor equipped with a reflux condenser and stirred to dissolve. Maleic anhydride, p-toluenesulfonic acid, and dicumyl peroxide are added. The temperature is controlled at 135-145°C, the reflux condenser is turned on, and the reaction is kept at a constant temperature for 4-6 hours. The xylene solvent and trace amounts of water are removed by vacuum distillation. After cooling to 70-80°C, the impurities are removed by filtration to obtain the carboxyl-terminated modified high-temperature resistant fatty acid ester internal lubricating dispersant.

[0060] The addition ratio of pentaerythritol oleate, xylene, maleic anhydride, p-toluenesulfonic acid, and dicumyl peroxide is 100g: 150-250mL: 8-15g: 0.3-0.5g: 0.5-1g.

[0061] As a further aspect of the present invention: the extrusion temperature of the inner sheath layer is 170-190℃, and the dynamic friction coefficient of the inner sheath surface is less than 0.12. The modules will not stick together and can still be easily separated after long-term use. The thermoplastic polyurethane elasticity gives the material excellent flexibility and repeated bending performance, making it suitable for complex laying paths.

[0062] The method for preparing a temperature-resistant and flame-retardant communication optical cable includes the following steps: alternately wrapping an optical fiber transmission layer and a wrapping layer on the surface of an intermediate reinforcing member, and then wrapping a sheath layer on the surface of the outermost optical fiber transmission layer to obtain a temperature-resistant and flame-retardant communication optical cable.

[0063] The beneficial effects of this invention are:

[0064] (1) In this application, epoxy silane modified PTFE micro powder and carboxyl-terminated modified high temperature resistant fatty acid ester internal lubricating dispersant are added to the inner sheath layer as friction-reducing components, and phosphate ester coupling agent is used to modify APP flame retardant to achieve low friction, flexible flame retardant and easy peeling performance, which solves the problems of large micro-bending loss, high tube resistance, module adhesion and poor scene adaptability of traditional optical cable inner sheath layer.

[0065] This application first activates the surface of PTFE micropowder through low-temperature plasma etching to introduce hydroxyl active sites, and then performs a hydrolysis-condensation reaction with epoxy silane to graft stable epoxy active groups onto the PTFE surface, forming epoxy silane-modified PTFE micropowder with PTFE hard lubricant as the core and silane organic layer as the shell. This structure can not only form a high-strength chemical bond with the TPU matrix molecular chain, eliminating the problems of PTFE micropowder migration, precipitation, and agglomeration, but also the excess epoxy active groups on the surface can undergo bonding reactions with modified lubricant, providing a chemical basis for the synergistic effect of the two components, stably maintaining the dynamic friction coefficient ≤0.12, and achieving long-term friction reduction;

[0066] This application utilizes carboxyl-terminated functionalized high-temperature resistant fatty acid esters with a heat resistance temperature ≥210℃, perfectly compatible with extrusion processes at 170-190℃, exhibiting no volatility or decomposition failure. The carboxyl groups at the ends of the additive's molecular chain can undergo ring-opening esterification reactions with the epoxy groups on the surface of epoxy-modified PTFE, forming a chemically bonded organic-inorganic synergistic lubrication system, overcoming the limitations of traditional physical mixing. On one hand, it acts as an internal dispersing lubricant, reducing TPU melt viscosity, decreasing lateral extrusion pressure, lowering fiber microbending loss, and uniformly dispersing the powdered additives; on the other hand, it is firmly anchored to the surface of PTFE micropowder through chemical bonds, constructing a composite lubrication structure of a flexible lubricating coating layer and a hard, wear-resistant PTFE core.

[0067] This application also adds a hindered phenolic heat stabilizer, which is suitable for the extrusion temperature range of 170-190℃, effectively suppressing the risk of slight decomposition of epoxy silane modified PTFE micro powder at 170-190℃, stabilizing the molecular structure of the material, improving the long-term temperature resistance and anti-aging performance of the inner sheath layer, making it suitable for the high-temperature and closed operating environment of the intelligent computing park computer room, and extending the service life of the optical cable.

[0068] This application employs a phosphate ester coupling agent to surface-modify ammonium polyphosphate (APP). By introducing pyrophosphoryloxy functional groups onto the APP surface, the interfacial bonding and compatibility between APP and the TPU matrix are significantly improved, effectively preventing APP agglomeration and precipitation in the TPU matrix and fiber microbending loss caused by interfacial defects. Simultaneously, the phosphorus element in the phosphate ester coupling agent synergistically works with the phosphorus-nitrogen flame-retardant structure in the APP, fundamentally inhibiting the hydrolytic catalytic degradation effect of unmodified APP on the TPU ester groups under high temperature and high humidity environments, while maintaining the V-0 flame retardant rating and limiting oxygen index of the inner sheath layer of not less than 30%. This results in a tensile strength retention rate of ≥85% after 100℃×168h heat aging of the inner sheath layer, significantly improving the long-term service reliability of the inner sheath layer in the enclosed high-temperature computer room of a smart computing park. This solves the industry technical problem of mechanical property degradation and shortened aging life caused by interfacial incompatibility in traditional APP flame-retardant TPU systems.

[0069] (2) This application adds hyperbranched modified sepiolite, core-shell microencapsulated phosphorus and nitrogen flame retardant, anti-UV stabilizer and boron-containing crosslinking agent to the outer sheath layer, which solves the technical problems of low flame retardancy efficiency, poor weather resistance and deterioration of mechanical properties under high filling in traditional outdoor optical cable sheaths, and achieves a comprehensive performance balance of high flame retardancy, high weather resistance and high mechanical strength.

[0070] This application first introduces phosphorus and aluminum flame-retardant elements into the surface of sepiolite through a chemical reaction between aluminum dihydrogen phosphate and the silanol groups on the surface of sepiolite, forming chemical bonds. Then, it utilizes the amidation reaction between the terminal amino groups of the hyperbranched polymer and the residual hydroxyl and phosphate groups on the sepiolite surface to graft hyperbranched macromolecular chains onto the aluminum dihydrogen phosphate-modified sepiolite surface, thus preparing hyperbranched modified sepiolite. On the one hand, the chemical anchoring of aluminum dihydrogen phosphate introduces phosphorus-aluminum flame-retardant active sites; on the other hand, the three-dimensional dendritic structure of the hyperbranched polymer provides a large number of end-group functional groups, forming multi-point chemical bonds and physical entanglement with the HDPE matrix, effectively preventing the agglomeration of sepiolite. During combustion, the hyperbranched modified sepiolite, as a rigid char-forming skeleton, synergistically forms a dense char layer with the phosphorus and nitrogen flame retardants, significantly improving flame-retardant efficiency.

[0071] This application employs the CTAB template method to synthesize a boron-containing mesoporous silica shell in situ on the surface of ammonium polyphosphate, and further coats it with a maleic anhydride-grafted polyethylene wax outer layer to prepare a core-shell microencapsulated phosphorus-nitrogen flame retardant. During combustion, the mesoporous shell can confined and slowly release active species such as phosphoric acid generated from the decomposition of APP, achieving controlled release and long-lasting flame retardancy. The boron element introduced by the co-hydrolysis of tributyl borate forms a Si-OB crosslinking network with silicon, significantly enhancing the high-temperature thermal stability of the char layer. The MAH-g-PE shell achieves chemical bonding through the esterification reaction of maleic anhydride groups with the hydroxyl groups on the surface of the mesoporous SiO2 shell. Simultaneously, its polyethylene wax segments exhibit excellent compatibility with the HDPE matrix, achieving permanent anchoring and uniform dispersion of the flame retardant within the matrix.

[0072] This application incorporates triethanolamine borate as a boron-containing crosslinking agent in the outer sheath layer, forming a synergistic "inner and outer double boron" crosslinking network with the boron-containing siloxane in the core-shell microencapsulated phosphorus-nitrogen flame retardant intermediate layer. During combustion, triethanolamine borate promotes the crosslinking of HDPE / POE matrix resin into char, while the boron-containing siloxane shell layer enhances the high-temperature stability of the char layer. The synergistic effect of inner and outer boron constructs a phosphorus-boron-silicon-clay quaternary flame retardant network.

[0073] This application utilizes a sol-gel method to coat a dense SiO2 shell onto the surface of carbon black, achieving physical isolation and anchoring of the carbon black. Then, through a chemical grafting reaction between KH570 silane coupling agent and the hydroxyl groups on the SiO2 shell surface, reactive double-bonded functional groups are introduced. This forms a mechanism where carbon black absorbs ultraviolet light, the SiO2 shell physically blocks carbon black migration and reflects some ultraviolet light, and the KH570 outer layer is chemically bonded to the HDPE matrix, achieving reactive permanent anchoring of UV-resistant particles. This solves the problems of migration, agglomeration, precipitation, and detachment of traditional carbon black under long-term ultraviolet aging and high / low temperature alternating conditions, enabling the outer sheath to maintain excellent weather resistance and anti-aging performance under long-term outdoor exposure to sunlight and rain.

[0074] (3) The optical cable of this application meets the UL-OFNR and CPR-Cca flame retardant standards, is suitable for indoor computer rooms, cabinets and other scenarios, and avoids the generation of toxic and harmful gases in case of fire. The optical cable prepared by this application based on the above-mentioned sheath layer and inner sheath layer also meets the -40℃ anti-freezing test; the water blocking strip in the optical cable of this application adopts longitudinal overlapping, and water blocking yarn can also be set in the longitudinal direction to achieve full water blocking in the longitudinal and radial directions, which is suitable for outdoor humid and rainy environments and prevents water infiltration from causing the optical fiber attenuation to exceed the standard; the optical cable sheath layer adopts non-metallic reinforcement, and FRP reinforcement is embedded in the sheath layer, which can be used in harsh pipeline conditions.

[0075] The optical cable prepared in this application has an optical fiber transmission layer composed of multiple tightly arranged optical fiber unit modules. Each optical fiber unit module contains 1-24 fiber bundles, which are composed of multiples of 8 or 16 cores. The surface of the fiber bundles is distinguished by different array ink dots, and different colored polyester yarns can be wound and fixed in multiples. Through modular stacking, the number of cores can be covered from 876 to 13824. Furthermore, the inner and outer sheaths of the optical cable prepared in this application adopt a composite design with differentiated materials, taking into account both indoor flame retardancy and outdoor weather resistance. There is no need to distinguish between indoor and outdoor optical cables. A single optical cable can traverse all scenarios such as equipment rooms, ducts, and outdoor overhead installations, reducing switching nodes and lowering link loss and failure risk.

[0076] During use, the optical cable prepared in this application allows for direct extraction of individual fiber unit modules for high-density pre-connection connectors such as branch matching. The factory-prefabricated ends eliminate the need for on-site splicing, thus improving construction efficiency. Attached Figure Description

[0077] The invention will now be further described with reference to the accompanying drawings.

[0078] Figure 1 This is a cross-sectional view of the temperature-resistant and flame-retardant communication optical cable prepared in Example 4 of this application;

[0079] Figure 2 This is a cross-sectional view of the optical fiber unit module prepared in Embodiment 4 of this application;

[0080] Reference numerals: 1. Intermediate reinforcement; 2. Optical fiber; 3. Inner sheath layer; 4. Water-blocking polyester yarn; 5. Wrapping tape layer; 6. Sheath layer; 7. FRP reinforcement; 8. Tear cord. Detailed Implementation

[0081] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0082] Example 1: The preparation method of hyperbranched modified sepiolite includes the following steps:

[0083] A1: 100g of sepiolite with a particle size of 10μm was placed in 500mL of 1mol / L hydrochloric acid aqueous solution, and the reaction was carried out at 40℃ with stirring for 2h. After filtration, washing and drying, acid-activated sepiolite was obtained.

[0084] 100g of acid-activated sepiolite, 15g of aluminum dihydrogen phosphate, and 300mL of deionized water were added to a reaction flask. The reaction was carried out at 80℃ with stirring for 3 hours. After centrifugation, washing, and drying, aluminum dihydrogen phosphate-modified sepiolite was obtained.

[0085] A2: Add 10g of ethylenediamine and 40mL of methanol to a four-necked flask equipped with a reflux condenser, magnetic stir bar, and constant pressure dropping funnel. Stir until homogeneous under the protection of an ice-water bath and nitrogen. Add 80g of methyl acrylate dropwise over 2 hours. Maintain the temperature at 30℃ for 24 hours. Remove excess methanol and methyl acrylate by vacuum distillation to obtain a pale yellow oily liquid, which is the intermediate. Add 16g of the intermediate and 50mL of methanol to a four-necked flask equipped with a reflux condenser, magnetic stir bar, and constant pressure dropping funnel. Stir until homogeneous under the protection of an ice-water bath and nitrogen. Add 1g of ethylenediamine dropwise over 2 hours. Maintain the temperature at 25℃ for 24 hours. Remove excess methanol and ethylenediamine by vacuum distillation to obtain PAMAM.

[0086] Under a nitrogen atmosphere, 100g of aluminum dihydrogen phosphate-modified sepiolite and 300mL of xylene were added to a reaction flask for dispersion. 20g of PAMAM and 0.5g of p-toluenesulfonic acid were added, and the reaction was carried out at 130℃ under reflux for 6h. Xylene was removed by vacuum distillation, and the mixture was washed with acetone and dried to obtain hyperbranched modified sepiolite.

[0087] The preparation method of core-shell microencapsulated phosphorus-nitrogen flame retardant includes the following steps:

[0088] B1: 3g of hexadecyltrimethylammonium bromide, 250mL of anhydrous ethanol, and 25mL of deionized water were added to a reaction flask for dispersion. 100g of ammonium polyphosphate was added for dispersion. 28wt% ammonia was added to adjust the pH to 8.5. 20g of tetraethyl orthosilicate and 5g of tributyl borate were mixed and added to the reaction flask. The reaction was carried out at 40℃ with stirring for 4 hours. After centrifugation, washing, and drying, a solid was obtained.

[0089] An acidified ethanol solution was prepared by mixing 500 mL of anhydrous ethanol, 10 mL of 38 wt% concentrated hydrochloric acid, and 30 mL of deionized water. 100 g of solid was placed in the acidified ethanol solution and extracted under reflux at 75 °C for 4 h. After cooling and centrifugation, the extraction was repeated 3 times. The solid was washed and dried to obtain the intermediate.

[0090] B2: Under a nitrogen atmosphere, 10g of maleic anhydride-grafted polyethylene wax (purchased from CERONAS ADDIMER 630R) and 200mL of xylene were added to a reaction flask. The temperature was controlled at 120℃, and the mixture was stirred to dissolve. 100g of intermediate was added for dispersion, and the mixture was kept at the temperature for 2 hours under stirring. After centrifugation, washing, and drying, the core-shell microencapsulated phosphorus-nitrogen flame retardant was obtained.

[0091] The preparation method of the UV stabilizer includes the following steps:

[0092] C1: 100g carbon black and 400mL anhydrous ethanol were added to a reaction flask for dispersion, 30g tetraethyl orthosilicate was added for dispersion, 40mL deionized water was added, and 28wt% ammonia was added to adjust the pH to 9. The reaction was carried out at 35℃ with stirring for 6h. After centrifugation, washing and drying, silica-coated carbon black was obtained.

[0093] C2: Add 300 mL of anhydrous ethanol and 20 mL of deionized water to the reaction flask for dispersion, add glacial acetic acid to adjust the pH to 4, add 8 g of KH570 for dispersion, add 100 g of silica to coat carbon black, control the temperature at 60℃ and keep the reaction at this temperature for 3 h, centrifuge, wash and dry to obtain the UV stabilizer.

[0094] The preparation method of epoxy silane modified PTFE micro powder includes the following steps:

[0095] D1: Low-temperature air plasma was used to etch and activate the surface of PTFE micro powder with a particle size of 1μm. The discharge power was 200W and the processing time was 10min to obtain pre-activated PTFE micro powder.

[0096] D2: Add 280 mL of anhydrous ethanol and 30 mL of deionized water to the reaction flask and disperse evenly. Add glacial acetic acid to adjust the pH of the system to 4.5. Add 4 g of KH560 for dispersion and hydrolysis. Add 100 g of pre-activated PTFE micro powder. Control the temperature at 65℃ and keep the reaction at this temperature for 3 h under stirring. Centrifuge, filter, wash, and dry to obtain epoxy silane modified PTFE micro powder.

[0097] The preparation method of carboxyl-terminated modified fatty acid ester internal lubricant dispersant includes the following steps: Under a nitrogen atmosphere, 100g of pentaerythritol oleate and 150mL of xylene are added to a reactor equipped with a reflux condenser and stirred to dissolve. 8g of maleic anhydride, 0.3g of p-toluenesulfonic acid, and 0.5g of dicumyl peroxide are added. The temperature is controlled at 135℃, and the reflux condenser is turned on. The reaction is kept at a constant temperature for 4h. The temperature is controlled at 150℃ and the vacuum degree is 0.09MPa. The xylene solvent and trace amounts of water are removed by vacuum distillation. After cooling to 70℃, the mixture is filtered to remove impurities, and the carboxyl-terminated modified high-temperature resistant fatty acid ester internal lubricant dispersant is obtained.

[0098] The preparation method of phosphate ester coupling agent modified APP includes the following steps: 100g APP and 300mL anhydrous ethanol are added to a reaction flask and dispersed evenly. 3g isopropyl tris(dioctylpyrophosphoryloxy) titanate is added and dispersed. 5mL deionized water is added and dispersed. The reaction is carried out at 60℃ with stirring for 2h. After centrifugation, washing and drying, phosphate ester coupling agent modified APP is obtained.

[0099] The preparation method of the sheath layer masterbatch includes the following steps: 65 parts by weight of high-density polyethylene (melt index 0.5 g / 10 min), 12 parts by weight of ethylene-octene copolymer elastomer toughening agent (3300POE elastomer purchased from Dow), 10 parts by weight of hyperbranched modified sepiolite prepared in Example 1, 25 parts by weight of core-shell microencapsulated phosphorus-nitrogen flame retardant prepared in Example 1, 5 parts by weight of UV stabilizer prepared in Example 1, 1 part by weight of triethanolamine borate ester is added and blended, 0.3 parts by weight of antioxidant 1010, 0.3 parts by weight of antioxidant 168, and 0.7 parts by weight of calcium stearate are added and blended, and the sheath layer masterbatch is obtained by extrusion using a twin-screw extruder.

[0100] The preparation method of the inner sheath masterbatch includes the following steps: 75 parts by weight of thermoplastic polyurethane elastomer (Desmopan 385 purchased from Covestro), 6.5 parts by weight of epoxy silane modified PTFE micro powder prepared in Example 1, 1 part by weight of carboxyl-terminated modified fatty acid ester internal lubricant dispersant prepared in Example 1, 12.5 parts by weight of phosphate ester coupling agent modified APP prepared in Example 1, 4 parts by weight of compatibilizer (MD715 maleic anhydride grafted POE purchased from Mitsui Chemicals), 0.4 parts by weight of antioxidant 1010, and 0.2 parts by weight of antioxidant 168 are blended and extruded using a twin-screw extruder to obtain the inner sheath masterbatch.

[0101] Example 2: The preparation method of hyperbranched modified sepiolite includes the following steps:

[0102] A1: 100g of sepiolite with a particle size of 10μm was placed in 500mL of 1mol / L hydrochloric acid aqueous solution, and the reaction was carried out at 40℃ with stirring for 2h. After filtration, washing and drying, acid-activated sepiolite was obtained.

[0103] 100g of acid-activated sepiolite, 20g of aluminum dihydrogen phosphate, and 400mL of deionized water were added to a reaction flask. The reaction was carried out at 85℃ with stirring for 4.5h. After centrifugation, washing, and drying, aluminum dihydrogen phosphate-modified sepiolite was obtained.

[0104] A2: Add 10g of ethylenediamine and 40mL of methanol to a four-necked flask equipped with a reflux condenser, magnetic stir bar, and constant pressure dropping funnel. Stir until homogeneous under the protection of an ice-water bath and nitrogen. Add 80g of methyl acrylate dropwise over 2 hours. Maintain the temperature at 30℃ for 24 hours. Remove excess methanol and methyl acrylate by vacuum distillation to obtain a pale yellow oily liquid, which is the intermediate. Add 16g of the intermediate and 50mL of methanol to a four-necked flask equipped with a reflux condenser, magnetic stir bar, and constant pressure dropping funnel. Stir until homogeneous under the protection of an ice-water bath and nitrogen. Add 1g of ethylenediamine dropwise over 2 hours. Maintain the temperature at 25℃ for 24 hours. Remove excess methanol and ethylenediamine by vacuum distillation to obtain PAMAM.

[0105] Under a nitrogen atmosphere, 100g of aluminum dihydrogen phosphate modified sepiolite and 400mL of xylene were added to a reaction flask for dispersion. 25g of PAMAM and 0.5-1g of p-toluenesulfonic acid were added, and the reaction was carried out at 135℃ under reflux for 7.5h. Xylene was removed by vacuum distillation, and the mixture was washed with acetone and dried to obtain hyperbranched modified sepiolite.

[0106] The preparation method of core-shell microencapsulated phosphorus-nitrogen flame retardant includes the following steps:

[0107] B1: 4.5g of hexadecyltrimethylammonium bromide, 300mL of anhydrous ethanol, and 30mL of deionized water were added to a reaction flask for dispersion. 100g of ammonium polyphosphate was added for dispersion, and 28wt% ammonia was added to adjust the pH to 9. 25g of tetraethyl orthosilicate and 7.5g of tributyl borate were mixed and added to the reaction flask. The reaction was carried out at 50℃ with stirring for 6 hours. After centrifugation, washing, and drying, a solid was obtained.

[0108] An acidified ethanol solution was prepared by mixing 500 mL of anhydrous ethanol, 10 mL of 38 wt% concentrated hydrochloric acid, and 30 mL of deionized water. 100 g of solid was placed in the acidified ethanol solution and extracted under reflux at 80 °C for 4.5 h. After cooling and centrifugation, the extraction was repeated 3 times. The solid was washed and dried to obtain the intermediate.

[0109] B2: Under a nitrogen atmosphere, 14g of maleic anhydride-grafted polyethylene wax (purchased from CERONAS ADDIMER 630R) and 250mL of xylene were added to a reaction flask. The temperature was controlled at 130℃, and the mixture was stirred to dissolve. 100g of intermediate was added for dispersion, and the reaction was kept at the temperature for 3 hours under stirring. After centrifugation, washing, and drying, the core-shell microencapsulated phosphorus-nitrogen flame retardant was obtained.

[0110] The preparation method of the UV stabilizer includes the following steps:

[0111] C1: 100g carbon black and 500mL anhydrous ethanol were added to a reaction flask for dispersion, 40g tetraethyl orthosilicate was added for dispersion, 50mL deionized water was added, and 28wt% ammonia was added to adjust the pH to 10. The reaction was carried out at 45℃ with stirring for 9h. After centrifugation, washing and drying, silica-coated carbon black was obtained.

[0112] C2: Add 400 mL of anhydrous ethanol and 20 mL of deionized water to the reaction flask for dispersion, add glacial acetic acid to adjust the pH to 5, add 10 g of KH570 for dispersion, add 100 g of silica to coat carbon black, control the temperature at 70℃ and keep the reaction at this temperature for 4.5 h, centrifuge, wash and dry to obtain the UV stabilizer.

[0113] The preparation method of epoxy silane modified PTFE micro powder includes the following steps:

[0114] D1: Low-temperature air plasma was used to etch and activate the surface of PTFE micro powder with a particle size of 1μm. The discharge power was 200W and the processing time was 10min to obtain pre-activated PTFE micro powder.

[0115] D2: Add 300 mL of anhydrous ethanol and 30 mL of deionized water to the reaction flask and disperse evenly. Add glacial acetic acid to adjust the pH of the system to 5. Add 5 g of KH560 for dispersion and hydrolysis. Add 100 g of pre-activated PTFE micro powder. Control the temperature at 70℃ and keep the reaction at this temperature for 4.5 h under stirring. Centrifuge, filter, wash, and dry to obtain epoxy silane modified PTFE micro powder.

[0116] The preparation method of the carboxyl-terminated modified fatty acid ester internal lubricant dispersant includes the following steps: Under a nitrogen atmosphere, 100g of pentaerythritol oleate and 200mL of xylene are added to a reactor equipped with a reflux condenser and stirred to dissolve. Then, 11g of maleic anhydride, 0.4g of p-toluenesulfonic acid, and 0.7g of dicumyl peroxide are added. The temperature is controlled at 140℃, and the reflux condenser is turned on. The reaction is kept at a constant temperature for 5h. The xylene solvent and trace amounts of water are removed by vacuum distillation at 150℃ and a vacuum degree of 0.09MPa. After cooling to 75℃, the mixture is filtered to remove impurities, and the carboxyl-terminated modified high-temperature resistant fatty acid ester internal lubricant dispersant is obtained.

[0117] The preparation method of phosphate ester coupling agent modified APP includes the following steps: 100g APP and 350mL anhydrous ethanol are added to a reaction flask and dispersed evenly. 5g isopropyl tris(dioctylpyrophosphoryloxy) titanate is added for dispersion. 7mL deionized water is added for dispersion. The reaction is carried out at 65℃ with stirring for 3h. After centrifugation, washing, and drying, phosphate ester coupling agent modified APP is obtained.

[0118] The preparation method of the sheath layer masterbatch is the same as that of Example 1, except that the hyperbranched modified sepiolite, core-shell microencapsulated phosphorus and nitrogen flame retardant and UV stabilizer prepared in Example 1 are replaced in equal amounts with the hyperbranched modified sepiolite, core-shell microencapsulated phosphorus and nitrogen flame retardant and UV stabilizer prepared in Example 2. The remaining components and preparation methods are completely consistent with those of Example 1.

[0119] The preparation method of the inner sheath layer masterbatch is the same as that of Example 1, except that the epoxy silane modified PTFE micro powder, carboxyl-terminated modified fatty acid ester internal lubricant dispersant, and phosphate ester coupling agent modified APP prepared in Example 1 are replaced in equal amounts with the epoxy silane modified PTFE micro powder, carboxyl-terminated modified fatty acid ester internal lubricant dispersant, and phosphate ester coupling agent modified APP prepared in Example 2. The remaining components and preparation methods are completely consistent with those of Example 1.

[0120] Example 3: The preparation method of hyperbranched modified sepiolite includes the following steps:

[0121] A1: 100g of sepiolite with a particle size of 10μm was placed in 500mL of 1mol / L hydrochloric acid aqueous solution, and the reaction was carried out at 40℃ with stirring for 2h. After filtration, washing and drying, acid-activated sepiolite was obtained.

[0122] 100g of acid-activated sepiolite, 25g of aluminum dihydrogen phosphate, and 500mL of deionized water were added to a reaction flask. The reaction was carried out at 90℃ with stirring for 6 hours. After centrifugation, washing, and drying, aluminum dihydrogen phosphate-modified sepiolite was obtained.

[0123] A2: Add 10g of ethylenediamine and 40mL of methanol to a four-necked flask equipped with a reflux condenser, magnetic stir bar, and constant pressure dropping funnel. Stir until homogeneous under the protection of an ice-water bath and nitrogen. Add 80g of methyl acrylate dropwise over 2 hours. Maintain the temperature at 30℃ for 24 hours. Remove excess methanol and methyl acrylate by vacuum distillation to obtain a pale yellow oily liquid, which is the intermediate. Add 16g of the intermediate and 50mL of methanol to a four-necked flask equipped with a reflux condenser, magnetic stir bar, and constant pressure dropping funnel. Stir until homogeneous under the protection of an ice-water bath and nitrogen. Add 1g of ethylenediamine dropwise over 2 hours. Maintain the temperature at 25℃ for 24 hours. Remove excess methanol and ethylenediamine by vacuum distillation to obtain PAMAM.

[0124] Under a nitrogen atmosphere, 100g of aluminum dihydrogen phosphate modified sepiolite and 500mL of xylene were added to a reaction flask for dispersion. 30g of PAMAM and 1g of p-toluenesulfonic acid were added, and the reaction was carried out at 140℃ under reflux for 9h. Xylene was removed by vacuum distillation, and the mixture was washed with acetone and dried to obtain hyperbranched modified sepiolite.

[0125] The preparation method of core-shell microencapsulated phosphorus-nitrogen flame retardant includes the following steps:

[0126] B1: 6g of hexadecyltrimethylammonium bromide, 350mL of anhydrous ethanol, and 35mL of deionized water were added to a reaction flask for dispersion. 100g of ammonium polyphosphate was added for dispersion. 28wt% ammonia was added to adjust the pH to 9.5. 30g of tetraethyl orthosilicate and 10g of tributyl borate were mixed and added to the reaction flask. The reaction was carried out at 60℃ with stirring for 8 hours. After centrifugation, washing, and drying, a solid was obtained.

[0127] An acidified ethanol solution was prepared by mixing 500 mL of anhydrous ethanol, 10 mL of 38 wt% concentrated hydrochloric acid, and 30 mL of deionized water. 100 g of solid was placed in the acidified ethanol solution and extracted under reflux at 85 °C for 6 h. After cooling and centrifugation, the extraction was repeated 3 times. The solid was washed and dried to obtain the intermediate.

[0128] B2: Under a nitrogen atmosphere, 18g of maleic anhydride-grafted polyethylene wax (purchased from CERONAS ADDIMER 630R) and 300mL of xylene were added to a reaction flask. The temperature was controlled at 135℃, and the mixture was stirred to dissolve. 100g of intermediate was added for dispersion, and the reaction was carried out under stirring for 4 hours. The mixture was then centrifuged, washed, and dried to obtain a core-shell microencapsulated phosphorus-nitrogen flame retardant.

[0129] The preparation method of the UV stabilizer includes the following steps:

[0130] C1: 100g carbon black and 600mL anhydrous ethanol were added to a reaction flask for dispersion, 50g tetraethyl orthosilicate was added for dispersion, 60mL deionized water was added, and 28wt% ammonia was added to adjust the pH to 10. The reaction was carried out at 50℃ with stirring for 12h. After centrifugation, washing and drying, silica-coated carbon black was obtained.

[0131] C2: Add 400 mL of anhydrous ethanol and 30 mL of deionized water to the reaction flask for dispersion, add glacial acetic acid to adjust the pH to 5, add 12 g of KH570 for dispersion, add 100 g of silica to coat carbon black, control the temperature at 75℃ and keep the reaction at this temperature for 6 h, centrifuge, wash and dry to obtain the UV stabilizer.

[0132] The preparation method of epoxy silane modified PTFE micro powder includes the following steps:

[0133] D1: Low-temperature air plasma was used to etch and activate the surface of PTFE micro powder with a particle size of 1μm. The discharge power was 200W and the processing time was 10min to obtain pre-activated PTFE micro powder.

[0134] D2: Add 320 mL of anhydrous ethanol and 40 mL of deionized water to the reaction flask and disperse evenly. Add glacial acetic acid to adjust the pH of the system to 5.5. Add 6 g of KH560 for dispersion and hydrolysis. Add 100 g of pre-activated PTFE micro powder. Control the temperature at 75℃ and keep the reaction at this temperature for 6 h under stirring. Centrifuge, filter, wash, and dry to obtain epoxy silane modified PTFE micro powder.

[0135] The preparation method of the carboxyl-terminated modified fatty acid ester internal lubricant dispersant includes the following steps: Under a nitrogen atmosphere, 100g of pentaerythritol oleate and 250mL of xylene are added to a reactor equipped with a reflux condenser and stirred to dissolve. 15g of maleic anhydride, 0.5g of p-toluenesulfonic acid, and 1g of dicumyl peroxide are added. The temperature is controlled at 145℃, the reflux condenser is turned on, and the reaction is kept at a constant temperature for 6h. The xylene solvent and trace amounts of water are removed by vacuum distillation at 150℃ and a vacuum degree of 0.09MPa. After cooling to 70-80℃, the impurities are removed by filtration to obtain the carboxyl-terminated modified high-temperature resistant fatty acid ester internal lubricant dispersant.

[0136] The preparation method of phosphate ester coupling agent modified APP includes the following steps: 100g APP and 400mL anhydrous ethanol are added to a reaction flask and dispersed evenly. 8g isopropyl tris(dioctylpyrophosphoryloxy) titanate is added and dispersed. 10mL deionized water is added and dispersed. The reaction is carried out at 70℃ with stirring for 4h. After centrifugation, washing and drying, phosphate ester coupling agent modified APP is obtained.

[0137] The preparation method of the sheath layer masterbatch is the same as that of Example 1, except that the hyperbranched modified sepiolite, core-shell microencapsulated phosphorus and nitrogen flame retardant and UV stabilizer prepared in Example 1 are replaced in equal amounts with the hyperbranched modified sepiolite, core-shell microencapsulated phosphorus and nitrogen flame retardant and UV stabilizer prepared in Example 3. The remaining components and preparation methods are completely consistent with those of Example 1.

[0138] The preparation method of the inner sheath layer masterbatch is the same as that of Example 1, except that the epoxy silane modified PTFE micro powder, carboxyl-terminated modified fatty acid ester internal lubricant dispersant, and phosphate ester coupling agent modified APP prepared in Example 1 are replaced in equal amounts with the epoxy silane modified PTFE micro powder, carboxyl-terminated modified fatty acid ester internal lubricant dispersant, and phosphate ester coupling agent modified APP prepared in Example 3. The remaining components and preparation methods are completely consistent with those of Example 1.

[0139] Example 4 (Please refer to) Figure 1 , Figure 2 The method for preparing high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cables includes the following steps:

[0140] Intermediate reinforcing member 1 is made by extruding and foaming PP material onto the surface of FRP reinforcing material;

[0141] Water-blocking polyester yarn 4 is wound around the surface of 24 optical fibers 2 at a pitch of 15 mm, with a tension of 25 g, to form an optical fiber bundle; an inner sheath layer 3 with a thickness of 0.15 mm is extruded on the surface of a structure in which 12 optical fiber bundles are twisted together using the inner sheath layer masterbatch prepared in Example 1 to obtain an optical fiber unit module.

[0142] The fiber unit module is composed of a fiber transmission layer and wrapped around the intermediate reinforcement 1; a wrapping layer 5 is wrapped around the surface of the fiber transmission layer; the fiber transmission layer and the wrapping layer 5 are wrapped alternately, and finally 4 layers of fiber transmission layer and 3 layers of wrapping layer 5 are wrapped around the surface of the intermediate reinforcement 1.

[0143] A sheath layer with an embedded tear cord 8 is wrapped around the surface of the outermost optical fiber transmission layer. The sheath layer 6 with a thickness of 2 mm is obtained by extruding the sheath layer masterbatch prepared in Example 1 on the surface of the sheath layer 8. During the extrusion process of the sheath layer 6, an FRP reinforcement 7 is also set in the sheath layer 6 to obtain a temperature-resistant and flame-retardant communication optical cable.

[0144] Example 5 (Please refer to) Figure 1 The preparation method of high-density, high-temperature resistant and flame-retardant communication optical cable with large core count is the same as that of Example 4. The only difference is that the inner sheath masterbatch and sheath masterbatch prepared in Example 1 are replaced with the inner sheath masterbatch and sheath masterbatch prepared in Example 2 in equal amounts. The other components and preparation methods are completely the same as those of Example 4.

[0145] Example 6 (Please refer to) Figure 1 The preparation method of high-density, high-temperature resistant and flame-retardant communication optical cable with large core count is the same as that of Example 4. The only difference is that the inner sheath masterbatch and sheath masterbatch prepared in Example 1 are replaced in equal amounts with the inner sheath masterbatch and sheath masterbatch prepared in Example 3. The other components and preparation methods are completely the same as those of Example 4.

[0146] Comparative Example 1: The preparation method of the sheath layer masterbatch is the same as that of Example 2, except that the hyperbranched modified sepiolite prepared in Example 2 is replaced in equal amounts with aluminum dihydrogen phosphate modified sepiolite prepared in Example 2. The other components and preparation methods are completely consistent with those of Example 2.

[0147] The preparation method of high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable is the same as that of Example 5, except that the sheath layer masterbatch prepared in Example 2 is replaced in equal amounts with the sheath layer masterbatch prepared in Comparative Example 1. The remaining components and preparation methods are completely consistent with those of Example 5.

[0148] Comparative Example 2: The preparation method of the sheath layer masterbatch is the same as that of Example 2, except that the hyperbranched modified sepiolite prepared in Example 2 is removed. The remaining components and preparation methods are completely consistent with those of Example 2.

[0149] The preparation method of high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable is the same as that of Example 5, except that the sheath layer masterbatch prepared in Example 2 is replaced in equal amounts with the sheath layer masterbatch prepared in Comparative Example 2. The remaining components and preparation methods are completely consistent with those of Example 5.

[0150] Comparative Example 3: The preparation method of the core-shell microencapsulated phosphorus-nitrogen flame retardant includes the following steps:

[0151] 4.5 g of hexadecyltrimethylammonium bromide, 300 mL of anhydrous ethanol, and 30 mL of deionized water were added to a reaction flask for dispersion. 100 g of ammonium polyphosphate was added for dispersion, and 28 wt% ammonia was added to adjust the pH to 9. 25 g of tetraethyl orthosilicate and 7.5 g of tributyl borate were mixed and added to the reaction flask. The reaction was carried out at 50 °C with stirring for 6 h. After centrifugation, washing, and drying, a solid was obtained.

[0152] An acidified ethanol solution was prepared by mixing 500 mL of anhydrous ethanol, 10 mL of 38 wt% concentrated hydrochloric acid, and 30 mL of deionized water. 100 g of solid was placed in the acidified ethanol solution and extracted under reflux at 80 °C for 4.5 h. After cooling and centrifugation, the extraction was repeated 3 times. The solid was washed and dried to obtain a core-shell microencapsulated phosphorus-nitrogen flame retardant.

[0153] The preparation method of the sheath layer masterbatch is the same as that of Example 2, except that the core-shell microencapsulated phosphorus-nitrogen flame retardant prepared in Example 2 is replaced in equal amounts with the core-shell microencapsulated phosphorus-nitrogen flame retardant prepared in Comparative Example 3. The remaining components and preparation methods are completely consistent with those of Example 2.

[0154] The preparation method of high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable is the same as that of Example 5, except that the sheath layer masterbatch prepared in Example 2 is replaced in equal amounts with the sheath layer masterbatch prepared in Comparative Example 3. The other components and preparation methods are completely consistent with those of Example 5.

[0155] Comparative Example 4: The preparation method of the core-shell microencapsulated phosphorus-nitrogen flame retardant includes the following steps:

[0156] B1: Add 300 mL of anhydrous ethanol and 30 mL of deionized water to the reaction flask for dispersion, add 100 g of ammonium polyphosphate for dispersion, add 28 wt% ammonia water to adjust the pH to 9, add 25 g of tetraethyl orthosilicate and 7.5 g of tributyl borate to the reaction flask, keep the temperature at 50 ℃ and stir for 6 h, centrifuge, wash and dry to obtain solid;

[0157] B2: Under a nitrogen atmosphere, 14g of maleic anhydride-grafted polyethylene wax (purchased from CERONAS ADDIMER 630R) and 250mL of xylene were added to a reaction flask. The temperature was controlled at 130℃, and the mixture was stirred to dissolve. 100g of solid was added to disperse the mixture, and the reaction was carried out under stirring for 3 hours. The mixture was then centrifuged, washed, and dried to obtain a core-shell microencapsulated phosphorus-nitrogen flame retardant.

[0158] The preparation method of the sheath layer masterbatch is the same as that of Example 2, except that the core-shell microencapsulated phosphorus-nitrogen flame retardant prepared in Example 2 is replaced in equal amounts with the core-shell microencapsulated phosphorus-nitrogen flame retardant prepared in Comparative Example 4. The remaining components and preparation methods are completely consistent with those of Example 2.

[0159] The preparation method of high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable is the same as that of Example 5, except that the sheath layer masterbatch prepared in Example 2 is replaced in equal amounts with the sheath layer masterbatch prepared in Comparative Example 4. The remaining components and preparation methods are completely consistent with those of Example 5.

[0160] Comparative Example 5: The preparation method of the sheath layer masterbatch is the same as that of Example 2, except that the core-shell microencapsulated phosphorus-nitrogen flame retardant prepared in Example 2 is deleted. The remaining components and preparation methods are completely consistent with those of Example 2.

[0161] The preparation method of high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable is the same as that of Example 5, except that the sheath layer masterbatch prepared in Example 2 is replaced in equal amounts with the sheath layer masterbatch prepared in Comparative Example 5. The remaining components and preparation methods are completely consistent with those of Example 5.

[0162] Comparative Example 6 The preparation method of the UV stabilizer includes the following steps: 400 mL of anhydrous ethanol and 20 mL of deionized water are added to the reaction flask for dispersion, glacial acetic acid is added to adjust the pH to 5, 10 g of KH570 is added for dispersion, 100 g of carbon black is added, the temperature is controlled at 70℃ and the reaction is kept at this temperature for 4.5 h, centrifuged, washed and dried to obtain the UV stabilizer.

[0163] The preparation method of the sheath layer masterbatch is the same as that of Example 2, except that the UV stabilizer prepared in Example 2 is replaced in equal amounts with the UV stabilizer prepared in Comparative Example 6. The other components and preparation methods are completely consistent with those of Example 2.

[0164] The preparation method of high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable is the same as that of Example 5, except that the sheath layer masterbatch prepared in Example 2 is replaced in equal amounts with the sheath layer masterbatch prepared in Comparative Example 6. The remaining components and preparation methods are completely consistent with those of Example 5.

[0165] Comparative Example 7: The preparation method of the sheath layer masterbatch is the same as that of Example 2, except that the UV stabilizer prepared in Example 2 is removed. The remaining components and preparation methods are completely consistent with those of Example 2.

[0166] The preparation method of high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable is the same as that of Example 5, except that the sheath layer masterbatch prepared in Example 2 is replaced in equal amounts with the sheath layer masterbatch prepared in Comparative Example 7. The remaining components and preparation methods are completely consistent with those of Example 5.

[0167] Comparative Example 8: The preparation method of the inner sheath layer masterbatch is the same as that of Example 2, except that the epoxy silane modified PTFE micro powder prepared in Example 2 is replaced with pre-activated PTFE micro powder in an equal amount. The other components and preparation methods are completely consistent with those of Example 2.

[0168] The preparation method of high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable is the same as that of Example 5, except that the inner sheath layer masterbatch prepared in Example 2 is replaced in equal amounts with the inner sheath layer masterbatch prepared in Comparative Example 8. The remaining components and preparation methods are completely consistent with those of Example 5.

[0169] Comparative Example 9: The preparation method of the inner sheath layer masterbatch is the same as that of Example 2, except that the carboxyl-terminated modified fatty acid ester internal lubricant dispersant prepared in Example 2 is replaced with pentaerythritol oleate in equal amounts. The remaining components and preparation methods are completely consistent with those of Example 2.

[0170] The preparation method of high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable is the same as that of Example 5, except that the inner sheath layer masterbatch prepared in Example 2 is replaced in equal amounts with the inner sheath layer masterbatch prepared in Comparative Example 9. The other components and preparation methods are completely consistent with those of Example 5.

[0171] The preparation method of the inner sheath layer masterbatch in Comparative Example 10 is the same as that in Example 2, except that the phosphate ester coupling agent modified APP prepared in Example 2 is replaced with an equal amount of APP. The other components and preparation methods are completely consistent with those in Example 2.

[0172] The preparation method of high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable is the same as that of Example 5, except that the inner sheath layer masterbatch prepared in Example 2 is replaced in equal amounts with the inner sheath layer masterbatch prepared in Comparative Example 10. The remaining components and preparation methods are completely consistent with those of Example 5.

[0173] Comparative Example 11: The preparation method of the sheath layer masterbatch is the same as that of Example 2, except that the triethanolamine borate added in Example 2 is deleted. The remaining components and preparation methods are completely consistent with those of Example 2.

[0174] The preparation method of high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable is the same as that of Example 5, except that the sheath layer masterbatch prepared in Example 2 is replaced in equal amounts with the sheath layer masterbatch prepared in Comparative Example 11. The remaining components and preparation methods are completely consistent with those of Example 5.

[0175] Performance testing

[0176] 1. Sheath layer performance testing

[0177] 1.1 Mechanical properties of the sheath layer: The tensile strength and elongation at break of the sheath layer were tested according to GB / T 2951.11-2008. The test results are shown in Table 1.

[0178] 1.2 Heat aging resistance of sheath layer: The tensile strength and elongation at break of the sheath layer after heat aging at 100℃ for 168h were tested according to GB / T 2951.12-2008, and the tensile strength retention rate and elongation at break retention rate were calculated. The test results are shown in Table 1.

[0179] 1.3 UV aging resistance of the sheath layer: The tensile strength and elongation at break of the sheath layer after 720h of xenon lamp aging treatment were tested according to GB / T 16422.2-2022, and the tensile strength retention rate and elongation at break retention rate were calculated. The test results are shown in Table 1.

[0180] Table 1: Statistical Table of Mechanical Performance Test Data for Sheath Layer

[0181] As shown in Table 1, the sheath layer prepared in this application has excellent mechanical properties, as well as good resistance to heat oxidation and UV aging.

[0182] 1.4 Flame retardant performance of the sheath layer: Tested according to GB / T 2406.2-2009, the test results are shown in Table 2;

[0183] 1.5 Environmental stress resistance: Tested according to GB / T 1842-2008, the test results are shown in Table 2;

[0184] 1.6 Low-temperature bending performance: Tested according to GB / T 2951.14-2008, the test results are shown in Table 2;

[0185] 1.7 Sheath shrinkage rate: Tested according to GB / T 2951.13-2008, the test results are shown in Table 2;

[0186] Table 2: Statistical Table of Physical and Chemical Properties Test Data for Sheath Layer

[0187] As shown in Table 2, the sheath layer prepared in this application has excellent flame retardant properties and maintains good flexibility even at low temperatures.

[0188] 2. Inner sheath layer performance testing

[0189] 2.1 Coefficient of dynamic friction: Tested according to IEC 60794-1-130, the test results are shown in Table 3;

[0190] 2.2 Peel strength: Tested according to YD / T 901-2009, the test results are shown in Table 3;

[0191] 2.3 Limiting Oxygen Index: Tested according to GB / T 2406.2-2009, the test results are shown in Table 3;

[0192] 2.4. Tensile strength and elongation at break of the inner sheath: The test was conducted according to GB / T 1040.2-2022, and the tensile strength of the material was tested after environmental treatment at 100℃ for 168h according to GB / T2951.12-2008. The tensile strength retention rate after heat aging treatment was calculated. The test results are shown in Table 3.

[0193] Table 3: Statistical Table of Inner Sheath Layer Performance Test Data

[0194] As shown in Table 3, the inner sheath layer prepared in this application not only has excellent flame retardant and mechanical properties, but is also easy to peel off and has low resistance to pipe penetration, which can effectively prevent module adhesion and improve scene adaptability.

[0195] 3. Performance testing of finished optical cables

[0196] 3.1 Fiber attenuation coefficient: Tested according to GB / T 15972.40-2024, the test results are shown in Table 4;

[0197] 3.2 Bending-related attenuation: Tested according to GB / T 15972.47-2021, the test results are shown in Table 4;

[0198] 3.3. Repeated bending of optical cable: The test was carried out according to GB / T 7424.21-2021. After bending 100 times, the additional attenuation value of the optical fiber was measured. The test results are shown in Table 4.

[0199] Table 4: Statistical Table of Performance Test Data for Finished Optical Cables

[0200] As shown in Table 4, the optical fiber attenuation fluctuation of the optical cable prepared in this application is extremely small during long-term use, and it is suitable for 400G / 800G / 1.6T high-speed computing power optical transmission.

[0201] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable, characterized in that: The optical cable includes: Intermediate reinforcement; An optical fiber transmission layer, wherein multiple optical fiber transmission layers are sequentially wrapped around the outer periphery of the intermediate reinforcing member; A cladding layer is disposed between two adjacent optical fiber transmission layers; A sheath layer, which covers the outer periphery of the outermost optical fiber transmission layer; The sheath layer comprises the following raw materials in parts by weight: 60-70 parts high-density polyethylene, 10-15 parts toughening agent, 28-40 parts flame retardant, 4-6 parts UV stabilizer, 0.5-0.8 parts antioxidant, 0.5-1 parts calcium stearate, and 0.5-1.5 parts boron-containing crosslinking agent. The toughening agent is an ethylene-octene copolymer elastomer; The flame retardant is composed of 8-12 parts by weight of hyperbranched modified sepiolite and 20-28 parts by weight of core-shell microencapsulated phosphorus-nitrogen flame retardant. The hyperbranched modified sepiolite is prepared by reacting sepiolite with aluminum dihydrogen phosphate and then with an amino-terminated hyperbranched polymer. The core-shell microencapsulated phosphorus-nitrogen flame retardant consists of, from the inside out, a phosphorus-nitrogen flame retardant core, a borosilicate cross-linked intermediate layer, and a maleic anhydride-grafted polyethylene wax outer shell. The UV stabilizer consists of a conductive carbon black core, a silica intermediate layer, and a KH570 silane coupling agent organic outer layer, from the inside out. The optical fiber transmission layer is composed of multiple optical fiber unit modules; The fiber optic unit module is made by twisting one or more fiber bundles together and then extruding an inner sheath layer on the surface; a single fiber optic unit module contains 1-24 fiber bundles; the thickness of the inner sheath layer is 0.1-0.4 mm; The optical fiber bundle consists of 8-core or 16-core multiple optical fibers, and the surface of the optical fiber bundle is provided with array ink dots or wrapped with water-blocking yarn; the water-blocking polyester yarn is wound around the optical fiber bundle at a pitch of 10-20mm, and the release tension of the water-blocking polyester yarn is 20-30g.

2. The high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable according to claim 1, characterized in that, The intermediate reinforcement is any one of the following: FRP reinforcement material, FRP reinforcement material with PP material extruded and foamed on the surface, or FRP reinforcement material with a sheath layer extruded on the surface.

3. The high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable according to claim 1, characterized in that, An embedded tear cord wrapping layer is also provided between the sheath layer and the outermost optical fiber transmission layer.

4. The high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable according to claim 1, characterized in that, The sheath layer also contains embedded FRP reinforcement.

5. A high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable according to claim 1, characterized in that, The preparation method of the hyperbranched modified sepiolite includes the following steps: A1: Add acid-activated sepiolite, aluminum dihydrogen phosphate, and deionized water to a reaction flask, control the temperature at 80-90℃, and keep the reaction at this temperature for 3-6 hours under stirring. After centrifugation, washing, and drying, aluminum dihydrogen phosphate-modified sepiolite is obtained. A2: Under a nitrogen atmosphere, aluminum dihydrogen phosphate modified sepiolite and xylene were added to a reaction flask and dispersed. Then, terminal amino hyperbranched polymer and p-toluenesulfonic acid were added. The temperature was controlled at 130-140℃ and the reaction was refluxed for 6-9 hours. Xylene was removed by vacuum distillation, and the mixture was washed with acetone and dried to obtain hyperbranched modified sepiolite. The addition ratio of acid-activated sepiolite, aluminum dihydrogen phosphate, and deionized water in A1 is 100g: 15-25g: 300-500mL. The addition ratio of aluminum dihydrogen phosphate modified sepiolite, xylene, terminal amino hyperbranched polymer, and p-toluenesulfonic acid in A2 is 100g: 300-500mL: 20-30g: 0.5-1g; The preparation method of the core-shell microencapsulated phosphorus-nitrogen flame retardant includes the following steps: B1: Hexadecyltrimethylammonium bromide, anhydrous ethanol, and deionized water were added to a reaction flask for dispersion. Ammonium polyphosphate was added for dispersion, and the pH was adjusted to 8.5-9.

5. Tetraethyl orthosilicate and tributyl borate were mixed and added to the reaction flask. The reaction was carried out at a temperature of 40-60℃ with stirring for 4-8 hours. The mixture was then centrifuged, washed, and dried to obtain a solid. The solid was then refluxed in an acidified ethanol solution to remove hexadecyltrimethylammonium bromide. After washing and drying, an intermediate was obtained. B2: Under a nitrogen atmosphere, maleic anhydride-grafted polyethylene wax and xylene are added to a reaction flask. The temperature is controlled at 120-135℃, and the mixture is stirred and dissolved. An intermediate is added and dispersed. The mixture is kept at a constant temperature for 2-4 hours under stirring. After centrifugation, washing, and drying, a core-shell microencapsulated phosphorus-nitrogen flame retardant is obtained. The addition ratio of hexadecyltrimethylammonium bromide, anhydrous ethanol, deionized water, ammonium polyphosphate, tetraethyl orthosilicate, and tributyl borate in B1 is 3-6g: 250-350mL: 25-35mL: 100g: 20-30g: 5-10g; In B2, the addition ratio of maleic anhydride-grafted polyethylene wax, xylene, and intermediates is 10-18g: 200-300mL: 100g.

6. The high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable according to claim 1, characterized in that, The preparation method of the UV stabilizer includes the following steps: C1: Carbon black and anhydrous ethanol are added to a reaction flask and dispersed. Tetraethyl orthosilicate is added and dispersed. Deionized water is added and the pH is adjusted to 9-10. The temperature is controlled at 35-50℃ and the reaction is kept at this temperature for 6-12 hours under stirring. After centrifugation, washing and drying, silica-coated carbon black is obtained. C2: Add anhydrous ethanol and deionized water to the reaction flask for dispersion, adjust the pH to 4-5, add KH570 for dispersion, add silica to coat carbon black, control the temperature at 60-75℃ and keep the reaction at this temperature for 3-6 hours, centrifuge, wash and dry to obtain the UV stabilizer. The addition ratio of carbon black, anhydrous ethanol, tetraethyl orthosilicate, and deionized water in C1 is 100g: 400-600mL: 30-50g: 40-60mL; The addition ratio of anhydrous ethanol, deionized water, KH570, and silica-coated carbon black in C2 is 300-400mL: 20-30mL: 8-12g: 100g.

7. A high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable according to claim 1, characterized in that, The inner sheath layer comprises the following raw materials in parts by weight: 70-80 parts by weight of thermoplastic polyurethane elastomer, 5.5-10 parts by weight of friction-reducing modifier component, 10-15 parts by weight of flame retardant, 3-5 parts by weight of compatibilizer, and 0.4-0.7 parts by weight of antioxidant. The friction-reducing modifier consists of epoxy silane-modified PTFE micro powder and carboxyl-terminated fatty acid ester internal lubricant dispersant in a mass ratio of 5-8:0.5-2; the antioxidant consists of hindered phenolic antioxidant and phosphite antioxidant in a mass ratio of 0.3-0.5:0.1-0.2; and the flame retardant is phosphate ester coupling agent modified APP.

8. The method for preparing a high-core-count, high-density, temperature-resistant, and flame-retardant communication optical cable according to any one of claims 1-7, characterized in that, The process includes the following steps: alternately wrapping the surface of the intermediate reinforcing member with an optical fiber transmission layer and a wrapping layer, and then wrapping the surface of the outermost optical fiber transmission layer with a sheath layer to obtain a temperature-resistant and flame-retardant communication optical cable.

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