High-strength rat-proof optical cable and preparation method thereof

Abstract

The invention discloses a high-strength rat-proof optical cable and a preparation method thereof. The high-strength rat-proof optical cable comprises at least one reinforcing piece, at least one cable core distributed outside the reinforcing piece, an inner protective layer wrapping the cable core, an armor layer wrapping the inner protective layer and a rat-proof outer sheath wrapping the armor layer, and the cable core is composed of at least one optical fiber and a loose tube; wherein the rat-proof outer sheath is prepared from the following raw materials in parts by weight: 70 to 80 parts of linear low-density polyethylene, 20 to 30 parts of nylon 12, 5 to 8 parts of compatilizer, 15 to 20 parts of modified composite filler, 1 to 3 parts of antioxidant and 0.5 to 1 part of lubricant. According to the high-strength rat-proof optical cable, the LLDPE / nylon 12 alloy matrix with a specific formula is adopted in the outer sheath, and the modified composite filler is introduced, so that the finally prepared optical cable outer sheath has excellent mechanical strength and wear resistance, and an efficient, long-acting and environment-friendly biological rat-proof effect is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of optical cables, and in particular relates to a high-strength rodent-proof optical cable and a preparation method thereof. Background Art

[0002] Optical fiber cable, the core infrastructure of the modern information society, utilizes optical fiber (or fiber) as the transmission medium, coated and protected through a series of sophisticated processes. With its unparalleled advantages, including high transmission capacity, low attenuation loss, strong resistance to electromagnetic interference, and excellent confidentiality, it has been widely used in various fields, including long-distance trunk communications, metropolitan area networks, data center interconnection, and even fiber-to-the-home (FTTH), forming the cornerstone of the global information superhighway. To ensure the long-term and stable operation of optical fiber in complex real-world environments, the optical cable structure typically includes multiple layers of protection, such as reinforcement members, loose tubes, fillers, and jackets, to resist external factors such as tension, lateral pressure, bending, and temperature fluctuations.

[0003] However, the protection capabilities of existing conventional optical cables still face significant challenges in actual deployment and long-term operation. This is especially true in rodent-prone environments, such as outdoors, pipelines, rural areas, and warehouses. Gnawing by rodents and other animals has become a major cause of damage to optical cables and communication interruptions. To address this issue, the industry has developed a variety of rodent-proof optical cable technologies. One common approach is to add chemical aversives, such as bittering agents, to the sheath material, leveraging their repulsive taste to deter rodents. However, this approach is limited by individual rodent tolerance, and its long-term effectiveness is questionable. Another approach involves physical protection, such as adding metal armor (such as steel tape or wire) to the cable structure or using extremely hard, specialized engineering plastics (such as nylon) as the sheath.

[0004] Chinese patent application CN104371191A discloses a special material for preventing insects and rodents from biting communication cables and a preparation method thereof. The material is made of the following raw materials in parts by weight: 52-76 parts of polypropylene, 31-43 parts of ethylene-chlorotrifluoroethylene copolymer, 3-6 parts of benzyl benzoate, 4-6 parts of allyl diglycol dicarbonate, 2-4 parts of cycloheximide, 3-5 parts of tetrabasic lead sulfate, 10-15 parts of dicyclohexyl phthalate, 16-22 parts of spherical quartz sand, 2-4 parts of triphenyltin acetate, 1.5-2.5 parts of m-chloroaniline, 5-10 parts of dibutyl azelaic acid, 2-3 parts of monoisodecyl phenyl phosphite, 4-8 parts of chlorinated paraffin, 8-14 parts of barium metatitanate, 5-10 parts of coated red phosphorus, 1-2 parts of phenylethyl resorcinol, and 4.5-6.5 parts of additives. The special material for the sheath pipe of the present invention contains substances such as benzyl benzoate, triphenyltin acetate, and m-chloroaniline, which can greatly improve the insect and rodent resistance of the sheath pipe, effectively prevent the invasion of insects and rodents on the sheath pipe, ensure the safety and normal operation of the optical cable, and at the same time has excellent wear resistance, weather resistance, corrosion resistance, and temperature resistance, a long service life, and a wide range of applications. Chinese patent application CN113793724A discloses a cross-linked polyethylene insulated, environment-friendly, rat-proof, ant-proof, flame-retardant control cable, belonging to the technical field of cables. The cable includes a copper conductor, the outer surface of the copper conductor is coated with a cross-linked polyethylene insulation layer, the copper conductor and the cross-linked polyethylene insulation layer form a cable core, and seven cable cores form a group. The outer layer of each cable core is wrapped with a polyester tape to form a wrapped polyester tape layer, the outer layer of the wrapped polyester tape layer is coated with a copper wire braided layer, and the outer surface of the copper wire braided layer is coated with a rat-proof, ant-proof, flame-retardant polyolefin sheath; the rat-proof, ant-proof, flame-retardant polyolefin sheath is made of a rat-proof, ant-proof, flame-retardant polyolefin material, and an anti-rat and ant agent is added during the preparation of the rat-proof, ant-proof, flame-retardant polyolefin material; the rat-proof and ant-proof component in the rat-proof and ant-proof agent prepared by the present invention is a nonanoic acid vanillylamide-type anti-rat and ant agent, which is a synthetic capsaicin. The difference from the prior art is that the rat-proof and ant-proof agent not only has a rat-proof and ant-proof effect, but also has a certain flame retardant effect. However, the above patents all directly add rodent repellents to the sheath material by a physical mixing method. However, with long-term use, the sheath material will age, the material performance will deteriorate, and it will be more easily damaged by rats; on the other hand, the rodent repellent may precipitate, thereby losing the rodent repellent effect.

[0005] Therefore, it is of great significance to develop an optical cable with high strength and long rodent-proofing time in this field. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention aims to provide a high-strength rodent-proof optical cable and a preparation method thereof.

[0007] To achieve the above object, the present invention provides the following technical solutions: A high-strength rodent-proof optical cable comprises at least one strength member, at least one cable core distributed outside the strength member, an inner sheath wrapped around the cable core, an armor layer wrapped around the inner sheath, and a rodent-proof outer sheath wrapped around the armor layer, wherein the cable core is composed of at least one optical fiber and a loose tube; The rodent-proof outer sheath is made of the following raw materials, calculated by weight: 70-80 parts of linear low-density polyethylene, 20-30 parts of nylon 12, 5-8 parts of a compatibilizer, 15-20 parts of a modified composite filler, 1-3 parts of an antioxidant, and 0.5-1 parts of a lubricant.

[0008] In the present invention, a specially formulated LLDPE / nylon 12 alloy matrix is ​​used in the outer sheath, and a modified composite filler is creatively introduced. As a result, the final optical cable outer sheath not only has excellent mechanical strength, abrasion resistance and processing fluidity, but also achieves a highly efficient, long-lasting and environmentally friendly biological rodent control effect through the chemical functionalization design of the filler.

[0009] Preferably, the method for preparing the modified composite filler comprises the following steps: S1, adding nano-silica to an ethanol aqueous solution, then adding γ-glycidyloxypropyltrimethoxysilane, stirring to react, filtering, washing, and drying after the reaction is completed to obtain pretreated silica; S2. Adding composite silica to deionized water, followed by adding hydroxypropyl-β-cyclodextrin and triethylamine, and heating to react. After the reaction is completed, filtering, washing, and drying to obtain a solid product. Subsequently, adding the solid product to DMF, followed by adding 6-mercaptopyridine-3-carboxylic acid, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine, and reacting at a constant temperature. After the reaction is completed, filtering, washing, and drying to obtain organic silica; S3, adding the organic silica in step S2 to toluene, and then adding erucamide and azobisisobutyronitrile to carry out a mercapto-ene reaction. After the reaction is completed, filtering, washing, and drying to obtain composite silica; S4, adding capsaicin to ethanol, stirring evenly, then adding the composite silica in step S3, stirring and adsorbing, filtering and drying after the adsorption is completed, to obtain a modified composite filler.

[0010] Preferably, in step S1, the mass ratio of nano-silica to γ-glycidyloxypropyltrimethoxysilane is 80-90:7-10, the stirring reaction temperature is 50-60° C., and the reaction time is 3-4 h.

[0011] In the present invention, the modified composite filler uses nano-silica as its skeleton, which has a huge specific surface area and can provide sufficient reaction sites and interaction area with the matrix at a relatively small addition amount. At the same time, its inherent high hardness and high modulus provide basic rigidity and strength for the sheath material. The nano-silica is reacted with γ-glycidyloxypropyltrimethoxysilane to introduce epoxy groups on the surface of the nano-silica, which not only facilitates subsequent reactions but also improves the interfacial compatibility between the filler and the sheath material substrate.

[0012] Preferably, in step S2, the mass ratio of the composite silica, hydroxypropyl-β-cyclodextrin, and triethylamine is 80-90:10-15:3-5, the temperature of the heating reaction is 60-70°C, and the time is 5-7h; the mass ratio of the solid product, 6-mercaptopyridine-3-carboxylic acid, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine is 90-100:8-12:10-15:1-2, the temperature of the constant temperature reaction is 60-70°C, and the time is 4-7h.

[0013] In the present invention, hydroxypropyl-β-cyclodextrin is introduced into the silica through the reaction of the epoxy groups on the composite silica with the hydroxyl groups on the hydroxypropyl-β-cyclodextrin, so that the rodent repellent (capsaicin) added subsequently can be included and slowly released. The introduction of hydroxypropyl-β-cyclodextrin by chemical bonding can ensure its uniform dispersion in the sheath material and reduce its subsequent precipitation, thereby achieving a long-term rodent-proofing effect of the sheath material. Subsequently, the silica introduced with hydroxypropyl-β-cyclodextrin is subjected to an esterification reaction with 6-mercaptopyridine-3-carboxylic acid. On the one hand, highly active thiol groups are introduced, which provides the possibility for the subsequent grafting of long-chain molecules. At the same time, due to the presence of the pyridine ring, the metal ions generated during the degradation process can be complexed, playing a role in assisting antioxidant and delaying the aging of the sheath material, thereby improving the weather resistance of the sheath, thereby extending the long-term rodent-proofing function of the optical cable.

[0014] Preferably, in step S3, the mass ratio of the organic silica, erucamide, and azobisisobutyronitrile is 90-100:7-10:0.5-0.8, and the temperature of the mercapto-ene reaction is 70-80° C., and the time is 1-2 h.

[0015] In the present invention, erucamide is introduced into the organic silica through a mercapto-ene reaction, thereby avoiding the problem of insufficient compatibility with LLDPE in the sheathing material due to the introduction of hydroxypropyl-β-cyclodextrin into the silica. Erucamide has a long hydrophobic fatty chain similar to the structure of polyethylene, which can be physically entangled and embedded in the molecular chain of LLDPE. Through the "physical anchoring" effect, the filler is firmly fixed in the matrix, greatly improving the interfacial bonding force, thereby significantly improving the impact strength and toughness of the sheathing material. At the same time, erucamide itself is also a lubricant, which can improve processing fluidity.

[0016] Preferably, the mass ratio of capsaicin, ethanol and composite silicon dioxide in step S4 is 7-10:600-700:90-100, the temperature of the stirring adsorption is 40-50° C., and the time is 3-4 h.

[0017] In the present invention, capsaicin, a natural and highly effective biostimulant, is introduced into the modified composite filler through the inclusion complexation of hydroxypropyl-β-cyclodextrin, thereby achieving a long-lasting, highly effective, low-migration, and environmentally friendly rodent-proofing effect on the optical cable.

[0018] Preferably, the compatibilizer is maleic anhydride grafted POE.

[0019] Preferably, the antioxidant is one or more of antioxidant 168, antioxidant 1098, and antioxidant 1010; and the lubricant is silicone masterbatch.

[0020] Preferably, the preparation method of the rodent-proof outer sheath comprises the following steps: linear low-density polyethylene, nylon 12, compatibilizer, modified composite filler, antioxidant, and lubricant are weighed according to the formula amount, added into a high-speed mixer, mixed evenly, and then the mixture is added into a twin-screw extruder, extruded and granulated at 190-240°C to obtain the product.

[0021] The present invention also protects a method for preparing the high-strength rodent-proof optical cable as described above, comprising the following steps: Step 1: Making colored optical fibers: coloring the bare optical fibers into colored optical fibers of different colors; Step 2: Making the cable core: Using a secondary coating extruder to form a loose tube, and placing colored optical fibers of different colors into the loose tube, and winding them to form a single cable core; Step 3: Cabling multiple cable cores: The strength members and multiple cable cores are cabled in a stranding machine so that the strength members are located in the center and the multiple cable cores are located outside the strength members; Step 4: Making an inner sheath and an armor layer: Extrusion-coating a low-density polyethylene, medium-density polyethylene, or high-density polyethylene material onto the cable cores formed in step 3 to form an inner sheath, and weaving an aluminum tape onto the outer portion of the inner sheath to form an armor layer; Step 5: Making a rodent-proof outer sheath: Extruding a rodent-proof outer sheath over the armor layer using an extruder to obtain the high-strength rodent-proof optical cable.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The high-strength rodent-proof optical cable provided by the present invention adopts a specially formulated LLDPE / nylon 12 alloy matrix in the outer sheath and creatively introduces a modified composite filler, so that the final optical cable outer sheath not only has excellent mechanical strength, wear resistance and processing fluidity, but also achieves a high-efficiency, long-lasting and environmentally friendly biological rodent-proofing effect through the chemical functionalization design of the filler; the filler is evenly dispersed in the matrix and has good interfacial compatibility with the polymer matrix, synergistically improving the strength and tear resistance of the material, while giving the outer sheath excellent weather resistance and service life, thereby ensuring the long-term, stable and reliable operation of the optical cable in complex outdoor environments.

[0023] (2) The high-strength rat-proof optical cable provided by the present invention has a modified composite filler added, which solves the difficult problems of traditional rat-proof agents that are easy to migrate, easy to lose effectiveness, and affect material properties through multi-step chemical reactions; with nano-silica as the core, cyclodextrin with inclusion ability and mercaptopyridine carboxylic acid for connecting subsequent functional groups are grafted in sequence, and then long-chain erucamide is connected through an efficient mercapto-ene click chemical reaction. This structure firmly anchors the functional components on the filler, and the rat-proof active substance is stored in the cyclodextrin cavity through inclusion action, thereby achieving the sustained release of the rat-proof agent, greatly extending the effective period of the rat-proof function, and ensuring that the active ingredients will not pollute the environment due to migration. Or affect other layer structures of the optical cable; and cleverly uses 6-mercaptopyridine-3-carboxylic acid as a bridge molecule, one end of which is connected to cyclodextrin through a stable ester bond, and the other end exposes a highly active thiol group, which enables the subsequent use of "thiol-ene click chemistry" with mild reaction conditions, high yield and no by-products to graft erucamide. The introduction of the long carbon chain of erucamide not only improves the interfacial compatibility between the filler and the LLDPE / nylon matrix as a lubricating and compatibilizing component, but more importantly, the amide structure at its end can form hydrogen bonds with the nylon 12 molecular chain, acting as a physical cross-linking point, further enhancing the toughness and interlayer bonding strength of the composite material.

[0024] (3) The high-strength rat-proof optical cable provided by the present invention adopts molecular inclusion technology to load the rat-proof active substance (capsaicin). Compared with traditional physical blending, the hydrophobic inner cavity and hydrophilic outer wall of cyclodextrin are utilized to efficiently include the hydrophobic small molecule capsaicin in its cavity. This inclusion effect not only greatly improves the dispersion stability of these active substances in aqueous and polar environments, but more importantly, forms a microscopic "molecular capsule". When the inclusion balance is destroyed by the gnawing of rats, the active substance will be slowly released, thereby achieving a sustained release effect of the active substance. While ensuring the rat-proof effect, the unnecessary loss of the active substance is minimized, thereby extending the rat-proof time of the optical cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1Schematic diagram of the structure of the high-strength rodent-proof optical cable of the present invention.

[0026] In the figure, 1. reinforcement; 2. cable core; 3. loose tube; 4. optical fiber; 5. inner sheath; 6. armor layer; 7. rodent-proof outer sheath. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] Unless otherwise specified, the chemical reagents and materials in the present invention are purchased from commercial sources or synthesized from commercially purchased raw materials.

[0029] The brand of the linear low-density polyethylene is ExxonMobil LL 7020YB; the brand of the nylon 12 is French Arkema 35R53 SP01; the particle size of the nano-silica is 200-300 nm; the brand of the maleic anhydride grafted POE is Mitsui MA8510, and the grafting rate is 1%.

[0030] Example 1

[0031] A high-strength rodent-proof optical cable, comprising at least one strength member 1, at least one cable core 2 distributed outside the strength member 1, an inner sheath 5 wrapped around the cable core, an armor layer 6 wrapped around the inner sheath, and a rodent-proof outer sheath 7 wrapped around the armor layer, wherein the cable core 2 is composed of at least one optical fiber 4 and a loose tube 3; Among them, the rodent-proof outer sheath is made of the following raw materials, calculated by weight: 75 parts of linear low-density polyethylene, 25 parts of nylon 12, 7 parts of maleic anhydride grafted POE, 18 parts of modified composite filler, 2 parts of antioxidant 1098, and 0.8 parts of silicone masterbatch.

[0032] The preparation method of the modified composite filler comprises the following steps: S1. Add 85 g of nano-silica to 1 L of ethanol-water solution (volume ratio of ethanol to water is 4:1), then add 9 g of γ-glycidyloxypropyltrimethoxysilane, and stir at 55°C for 3.5 h. After the reaction is completed, filter, wash, and dry to obtain pretreated silica; S2, 85g of pretreated silica was added to 1.3L of deionized water, followed by the addition of 13g of hydroxypropyl-β-cyclodextrin and 4g of triethylamine, and the reaction was carried out at 65°C for 6h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a solid product. Subsequently, 95g of the solid product was added to 1.5L of DMF, followed by the addition of 10g of 6-mercaptopyridine-3-carboxylic acid, 13g of N,N'-dicyclohexylcarbodiimide, and 1.5g of 4-dimethylaminopyridine. The mixture was kept at a constant temperature for 6h at 65°C. After the reaction was completed, the mixture was filtered, washed, and dried to obtain an organic silica; S3, adding 95g of the organic silica in step S2 to 1.5L of toluene, followed by adding 9g of erucamide and 0.7g of azobisisobutyronitrile, and reacting at 75°C for 1.5h. After the reaction is complete, filtering, washing, and drying to obtain composite silica; S4. Add 9 g of capsaicin to 650 g of ethanol, stir evenly, then add 95 g of composite silica in step S3, stir and adsorb at 45° C. for 3.5 h, filter and dry after adsorption to obtain a modified composite filler.

[0033] The preparation method of the rodent-proof outer sheath comprises the following steps: linear low-density polyethylene, nylon 12, maleic anhydride-grafted POE, modified composite filler, antioxidant 1098, and silicone masterbatch are weighed according to the formula, added into a high-speed mixer, and mixed evenly; then, the mixture is added into a twin-screw extruder, and extruded and granulated at 230° C. to obtain the rodent-proof outer sheath.

[0034] Example 2

[0035] A high-strength rodent-proof optical cable, comprising at least one strength member 1, at least one cable core 2 distributed outside the strength member 1, an inner sheath 5 wrapped around the cable core, an armor layer 6 wrapped around the inner sheath, and a rodent-proof outer sheath 7 wrapped around the armor layer, wherein the cable core 2 is composed of at least one optical fiber 4 and a loose tube 3; The rodent-proof outer sheath is made of the following raw materials, calculated by weight: 80 parts of linear low-density polyethylene, 20 parts of nylon 12, 5 parts of maleic anhydride grafted POE, 15 parts of modified composite filler, 1 part of antioxidant 1098, and 0.5 parts of silicone masterbatch.

[0036] The preparation method of the modified composite filler comprises the following steps: S1. Add 80 g of nano-silica to 1 L of ethanol-water solution (volume ratio of ethanol to water is 4:1), then add 7 g of γ-glycidyloxypropyltrimethoxysilane, and stir at 50°C for 4 h. After the reaction is completed, filter, wash, and dry to obtain pretreated silica; S2, 80g of pretreated silica was added to 1.3L of deionized water, followed by the addition of 10g of hydroxypropyl-β-cyclodextrin and 3g of triethylamine, and the mixture was reacted at 60°C for 7h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a solid product. Subsequently, 90g of the solid product was added to 1.5L of DMF, followed by the addition of 8g of 6-mercaptopyridine-3-carboxylic acid, 10g of N,N'-dicyclohexylcarbodiimide, and 1g of 4-dimethylaminopyridine. The mixture was reacted at a constant temperature of 60°C for 7h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain an organic silica; S3, adding 90g of the organic silica in step S2 to 1.5L of toluene, followed by adding 6g of erucamide and 0.5g of azobisisobutyronitrile, and reacting at 70°C for 2h. After the reaction is complete, filtering, washing, and drying to obtain composite silica; S4. Add 7 g of capsaicin to 600 g of ethanol, stir evenly, then add 90 g of composite silica in step S3, stir and adsorb at 40° C. for 4 h, filter and dry after adsorption to obtain a modified composite filler.

[0037] The preparation method of the rodent-proof outer sheath comprises the following steps: linear low-density polyethylene, nylon 12, maleic anhydride-grafted POE, modified composite filler, antioxidant 1098, and silicone masterbatch are weighed according to the formula, added into a high-speed mixer, and mixed evenly; then, the mixture is added into a twin-screw extruder, and extruded and granulated at 230° C. to obtain the rodent-proof outer sheath.

[0038] Example 3

[0039] A high-strength rodent-proof optical cable, comprising at least one strength member 1, at least one cable core 2 distributed outside the strength member 1, an inner sheath 5 wrapped around the cable core, an armor layer 6 wrapped around the inner sheath, and a rodent-proof outer sheath 7 wrapped around the armor layer, wherein the cable core 2 is composed of at least one optical fiber 4 and a loose tube 3; The rodent-proof outer sheath is made of the following raw materials, calculated by weight: 70 parts of linear low-density polyethylene, 30 parts of nylon 12, 8 parts of maleic anhydride grafted POE, 20 parts of modified composite filler, 3 parts of antioxidant 1098, and 1 part of silicone masterbatch.

[0040] The preparation method of the modified composite filler comprises the following steps: S1. Add 90 g of nano-silica to 1 L of ethanol-water solution (volume ratio of ethanol to water is 4:1), then add 10 g of γ-glycidyloxypropyltrimethoxysilane, and stir at 60° C. for 3 h. After the reaction is completed, filter, wash, and dry to obtain pretreated silica; S2, 90g of pretreated silica was added to 1.3L of deionized water, followed by the addition of 15g of hydroxypropyl-β-cyclodextrin and 5g of triethylamine, and the mixture was reacted at 70°C for 5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a solid product. Subsequently, 100g of the solid product was added to 1.5L of DMF, followed by the addition of 12g of 6-mercaptopyridine-3-carboxylic acid, 15g of N,N'-dicyclohexylcarbodiimide, and 2g of 4-dimethylaminopyridine. The mixture was reacted at a constant temperature of 70°C for 4h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain an organic silica; S3, adding 100g of the organic silica in step S2 to 1.5L of toluene, followed by adding 10g of erucamide and 0.8g of azobisisobutyronitrile, and reacting at 80°C for 1h. After the reaction is complete, filtering, washing, and drying to obtain composite silica; S4. Add 10 g of capsaicin to 700 g of ethanol, stir evenly, then add 100 g of composite silica in step S3, stir and adsorb at 50° C. for 3 h, filter and dry after adsorption to obtain a modified composite filler.

[0041] The preparation method of the rodent-proof outer sheath comprises the following steps: linear low-density polyethylene, nylon 12, maleic anhydride-grafted POE, modified composite filler, antioxidant 1098, and silicone masterbatch are weighed according to the formula, added into a high-speed mixer, and mixed evenly; then, the mixture is added into a twin-screw extruder, and extruded and granulated at 230° C. to obtain the rodent-proof outer sheath.

[0042] Comparative Example 1

[0043] A high-strength rodent-proof optical cable, comprising at least one strength member 1, at least one cable core 2 distributed outside the strength member 1, an inner sheath 5 wrapped around the cable core, an armor layer 6 wrapped around the inner sheath, and a rodent-proof outer sheath 7 wrapped around the armor layer, wherein the cable core 2 is composed of at least one optical fiber 4 and a loose tube 3; Among them, the rodent-proof outer sheath is made of the following raw materials, calculated by weight: 75 parts of linear low-density polyethylene, 25 parts of nylon 12, 7 parts of maleic anhydride grafted POE, 18 parts of modified composite filler, 2 parts of antioxidant 1098, and 0.8 parts of silicone masterbatch.

[0044] The preparation method of the modified composite filler comprises the following steps: S1. Add 85 g of nano-silica to 1 L of ethanol-water solution (volume ratio of ethanol to water is 4:1), then add 9 g of γ-glycidyloxypropyltrimethoxysilane, and stir at 55°C for 3.5 h. After the reaction is completed, filter, wash, and dry to obtain pretreated silica; S2. Add 85 g of pretreated silica to 1.3 L of deionized water, then add 13 g of hydroxypropyl-β-cyclodextrin and 4 g of triethylamine, and react at 65 ° C for 6 h. After the reaction is completed, filter, wash, and dry to obtain organic silica; S3, adding 95g of the organic silica in step S2 to 1.5L of toluene, followed by adding 9g of erucamide and 0.7g of azobisisobutyronitrile, and reacting at 75°C for 1.5h. After the reaction is complete, filtering, washing, and drying to obtain composite silica; S4. Add 9 g of capsaicin to 650 g of ethanol, stir evenly, then add 95 g of composite silica in step S3, stir and adsorb at 45° C. for 3.5 h, filter and dry after adsorption to obtain a modified composite filler.

[0045] The preparation method of the rodent-proof outer sheath comprises the following steps: linear low-density polyethylene, nylon 12, maleic anhydride-grafted POE, modified composite filler, antioxidant 1098, and silicone masterbatch are weighed according to the formula, added into a high-speed mixer, and mixed evenly; then, the mixture is added into a twin-screw extruder, and extruded and granulated at 230° C. to obtain the rodent-proof outer sheath.

[0046] Compared with Example 1, this comparative example does not introduce 6-mercaptopyridine-3-carboxylic acid into the modified composite filler.

[0047] Comparative Example 2

[0048] A high-strength rodent-proof optical cable, comprising at least one strength member 1, at least one cable core 2 distributed outside the strength member 1, an inner sheath 5 wrapped around the cable core, an armor layer 6 wrapped around the inner sheath, and a rodent-proof outer sheath 7 wrapped around the armor layer, wherein the cable core 2 is composed of at least one optical fiber 4 and a loose tube 3; Among them, the rodent-proof outer sheath is made of the following raw materials, calculated by weight: 75 parts of linear low-density polyethylene, 25 parts of nylon 12, 7 parts of maleic anhydride grafted POE, 18 parts of modified composite filler, 2 parts of antioxidant 1098, and 0.8 parts of silicone masterbatch.

[0049] The preparation method of the modified composite filler comprises the following steps: S1. Add 85 g of nano-silica to 1 L of ethanol-water solution (volume ratio of ethanol to water is 4:1), then add 9 g of γ-glycidyloxypropyltrimethoxysilane, and stir at 55°C for 3.5 h. After the reaction is completed, filter, wash, and dry to obtain pretreated silica; S2, 85g of pretreated silica was added to 1.3L of deionized water, followed by the addition of 13g of hydroxypropyl-β-cyclodextrin and 4g of triethylamine, and the reaction was carried out at 65°C for 6h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a solid product. Subsequently, 95g of the solid product was added to 1.5L of DMF, followed by the addition of 10g of 6-mercaptopyridine-3-carboxylic acid, 13g of N,N'-dicyclohexylcarbodiimide, and 1.5g of 4-dimethylaminopyridine. The mixture was kept at a constant temperature for 6h at 65°C. After the reaction was completed, the mixture was filtered, washed, and dried to obtain an organic silica; S3. Add 9 g of capsaicin to 650 g of ethanol, stir evenly, then add 95 g of the organic silica in step S2, stir and adsorb at 45° C. for 3.5 h, filter and dry after adsorption to obtain a modified composite filler.

[0050] The preparation method of the rodent-proof outer sheath comprises the following steps: linear low-density polyethylene, nylon 12, maleic anhydride-grafted POE, modified composite filler, antioxidant 1098, and silicone masterbatch are weighed according to the formula, added into a high-speed mixer, and mixed evenly; then, the mixture is added into a twin-screw extruder, and extruded and granulated at 230° C. to obtain the rodent-proof outer sheath.

[0051] Compared with Example 1, erucamide was not introduced into the modified composite particles in this comparative example.

[0052] The rodent-proof outer sheaths prepared in Examples 1-3 and Comparative Examples 1-2 were made into specimens for performance testing. The tensile strength and elongation at break were tested in accordance with GB / T 2951.11-2008 "General test methods for insulation and sheathing materials of electric and optical cables - Part 11: General test methods for thickness and dimensions - Mechanical properties test". The aging test was conducted in accordance with GB / T 2951.12-2008 "General test methods for insulation and sheathing materials of electric and optical cables - Part 12: General test methods for thermal aging test". The aging temperature was 100°C ± 2°C, the air exchange rate was 15 times per hour, and the test time was 240 hours. The rat bite test was conducted by drying the rat-proof outer sheath materials prepared in Examples 1-3 and Comparative Examples 1-2 in a 105°C forced air oven for 6 hours. The dried particles were injection molded into rectangular sheet samples of 150 mm × 30 mm on an injection molding machine. Twenty healthy test mice (half male and half female) (with no missing upper and lower incisors) were housed in cages, with one test mouse in each cage. The relevant requirements for test mice and cages were referred to GB / T The test was conducted in accordance with GB / T 29199-2012, "Test Method for Rodent Repellency of Optical Cables." Samples were placed in rat cages. After 7 days, the total number of tooth marks on the samples from 20 cages was recorded. These marks included both single and double tooth marks. The rats were fed normally during the test. Sample placement, tooth mark recording, and rat feeding procedures were performed in accordance with GB / T 29199-2012, "Test Method for Rodent Repellency of Optical Cables." Rodent repellency rating criteria are: Level 1, total number of tooth marks ≤ 5; Level 2, 5 < total number of tooth marks ≤ 10; Level 3, 10 < total number of tooth marks ≤ 20; Level 4, 20 < total number of tooth marks ≤ 30; Level 5, 30 < total number of tooth marks ≤ 50; and Level 6, total number of tooth marks > 50. The rat-resistant outer sheath was tested for its rodent-resistant performance before and after aging. The test results are shown in Table 1.

[0053] Table 1 Performance test results of each group of rodent-proof outer sheaths

[0054] As can be seen from the above table, the rodent-proof outer sheath prepared by the present invention has good mechanical properties and also has good long-term rodent-proof performance, thereby improving the strength and rodent-proof performance of the optical cable.

[0055] The above content is a further detailed description of the present invention in combination with specific implementation examples. It cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, they can make several simple deductions or substitutions without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

[0056] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-strength rodent-proof optical cable, characterized in that: The invention comprises at least one reinforcement member (1), at least one cable core (2) distributed outside the reinforcement member (1), an inner sheath (5) wrapped around the cable core, an armor layer (6) wrapped around the inner sheath, and a rodent-proof outer sheath (7) wrapped around the armor layer, wherein the cable core (2) is composed of at least one optical fiber (4) and a loose tube (3); The rodent-proof outer sheath is made of the following raw materials, calculated by weight: 70-80 parts of linear low-density polyethylene, 20-30 parts of nylon 12, 5-8 parts of a compatibilizer, 15-20 parts of a modified composite filler, 1-3 parts of an antioxidant, and 0.5-1 parts of a lubricant.

2. The high-strength rodent-proof optical cable according to claim 1, characterized in that: The preparation method of the modified composite filler comprises the following steps: S1, adding nano-silica to an ethanol aqueous solution, then adding γ-glycidyloxypropyltrimethoxysilane, stirring and reacting to obtain pretreated silica; S2. Add the pretreated silica to deionized water, then add hydroxypropyl-β-cyclodextrin and triethylamine, and heat to react. After the reaction is completed, filter, wash, and dry to obtain a solid product. Then, add the solid product to DMF, and then add 6-mercaptopyridine-3-carboxylic acid, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine to react at a constant temperature to obtain organic silica. S3, adding organic silica to toluene, and then adding erucamide and azobisisobutyronitrile to carry out a mercapto-ene reaction to obtain composite silica; S4. Add capsaicin to ethanol, stir evenly, then add composite silica, stir and adsorb, filter and dry after adsorption is completed to obtain a modified composite filler.

3. The high-strength rodent-proof optical cable according to claim 1, characterized in that: In step S1, the mass ratio of nano-silica to γ-glycidyloxypropyltrimethoxysilane is 80-90:7-10, the stirring reaction temperature is 50-60° C., and the time is 3-4 hours.

4. The high-strength rodent-proof optical cable according to claim 1, characterized in that: The mass ratio of the pretreated silica, hydroxypropyl-β-cyclodextrin, and triethylamine in step S2 is 80-90:10-15:3-5, the temperature of the heating reaction is 60-70°C, and the time is 5-7h; the mass ratio of the solid product, 6-mercaptopyridine-3-carboxylic acid, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine is 90-100:8-12:10-15:1-2, the temperature of the constant temperature reaction is 60-70°C, and the time is 4-7h.

5. The high-strength rodent-proof optical cable according to claim 1, characterized in that: In step S3, the mass ratio of the organic silica, erucamide, and azobisisobutyronitrile is 90-100:7-10:0.5-0.8, and the temperature of the mercapto-ene reaction is 70-80° C., and the time is 1-2 hours.

6. The high-strength rodent-proof optical cable according to claim 1, characterized in that: In step S4, the mass ratio of capsaicin, ethanol, and composite silicon dioxide is 7-10:600-700:90-100, the temperature of the stirring adsorption is 40-50° C., and the time is 3-4 hours.

7. The high-strength rodent-proof optical cable according to claim 1, characterized in that: The compatibilizer is maleic anhydride grafted POE.

8. The high-strength rodent-proof optical cable according to claim 1, characterized in that: The antioxidant is one or more of antioxidant 168, antioxidant 1098, and antioxidant 1010; and the lubricant is silicone masterbatch.

9. The high-strength rodent-proof optical cable according to claim 1, characterized in that: The preparation method of the rodent-proof outer sheath comprises the following steps: linear low-density polyethylene, nylon 12, a compatibilizer, a modified composite filler, an antioxidant, and a lubricant are weighed according to the formula, added into a high-speed mixer, and mixed evenly; then, the mixture is added into a twin-screw extruder, and extruded and granulated at 190-240° C. to obtain the rodent-proof outer sheath.

10. A method for preparing the high-strength rodent-proof optical cable according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Making colored optical fibers: coloring the bare optical fibers into colored optical fibers of different colors; Step 2: Making the cable core: Using a secondary coating extruder to form a loose tube, and placing colored optical fibers of different colors into the loose tube, and winding them to form a single cable core; Step 3: Cabling multiple cable cores: The strength members and multiple cable cores are cabled in a stranding machine so that the strength members are located in the center and the multiple cable cores are located outside the strength members; Step 4: Making an inner sheath and an armor layer: Extrusion-coating a low-density polyethylene, medium-density polyethylene, or high-density polyethylene material onto the cable cores formed in step 3 to form an inner sheath, and weaving an aluminum tape onto the outer portion of the inner sheath to form an armor layer; Step 5: Making a rodent-proof outer sheath: Extruding a rodent-proof outer sheath over the armor layer using an extruder to obtain the high-strength rodent-proof optical cable.

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